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1

Chemical Compositions of Stars  

NASA Astrophysics Data System (ADS)

In 1835, in a famously inaccurate forecast, the French philosopher Auguste Comte wrote of stars that, `We understand the possibility of determining their shapes, their distances, their sizes and their movements; whereas we would never know how to study by any means their chemical composition…'. At the close of the 20th century the accurate measurement of the abundances of the chemical elements in...

Leckrone, D.; Murdin, P.

2000-11-01

2

The Chemical Composition of Honey  

ERIC Educational Resources Information Center

Honey is a supersaturated sugar solution, created by bees, and used by human beings as a sweetener. However, honey is more than just a supersaturated sugar solution; it also contains acids, minerals, vitamins, and amino acids in varying quantities. In this article, we will briefly explore the chemical composition of honey. (Contains 2 figures and…

Ball, David W.

2007-01-01

3

Minerals by Chemical Composition  

NSDL National Science Digital Library

This interactive periodic table displays a listing of minerals by element, sorted by percent of the element. Clicking on a symbol on the table leads users to information on the element (atomic mass and number, name origin, year of discovery, and a brief description), and to a table listing each mineral known to contain the element in decreasing order by percentage. Each mineral name in the table is linked to additional information on the mineral, such as formula and composition, images, crystallography, physical properties, and many others.

4

Chemical recycling of scrap composites  

NASA Technical Reports Server (NTRS)

There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials.

Allred, Ronald E.; Salas, Richard M.

1994-01-01

5

Chemical Modification of Nanotubes for Composites  

NASA Technical Reports Server (NTRS)

In the production of mesoscopically-engineered materials based on single-walled carbon nanotubes (SWNTs), monitoring the stages of chemical modification will be an important step in the fabrication of usable composite materials. In our research program we developed tools for studying high-temperature composites with a long-term goal of having such instrumentation available for SWNT composite analyses.

Samulski, Edward T.

2003-01-01

6

Original article Chemical composition and coagulation properties  

E-print Network

composition was the same in both breeds. The pH of the Mo milk was lower (­0.07), coagulation time and curd' milk Vincenzo CHIOFALOa, Roberta MALDONATOa, Bruno MARTINb*, Didier DUPONTc, Jean-Baptiste COULONb October 2000) Abstract -- The chemical composition and clotting properties of milk from 45 Modicana (Mo

Paris-Sud XI, Université de

7

Boron Nitride Composites By Chemical Vapor Deposition  

Microsoft Academic Search

Composites of boron nitride (BN) have been made by the chemical vapor deposition (CVD) of a BN matrix on a BN felt fiber substrate. Reactant gases were boron trifluoride and ammonia. The composites have a relatively high density (1.70 g\\/cm3), a crystallite size LC = 150 A and an interlayer spacing d002 = 3.35 A. Measurements of elastic modulus and

Hugh O. Pierson

1975-01-01

8

Original article Anatomy and chemical composition  

E-print Network

, starch granules and tannins occur inside sieve and parenchyma cells. The rhytidome of P. pinea bark has résinifères apparaissent dans les rayons fusiformes. Des cristaux styloïdes, des granules d'amidon et des. pinea has not previously been charac- terised, although the anatomy and chemical composition of its wood

Paris-Sud XI, Université de

9

Chemical Composition of Anthropogenically Influenced Groundwater  

E-print Network

Chemical Composition of Anthropogenically Influenced Groundwater Jacqueline Gordon Brandeis of Biology 1 #12;ABSTRACT I examined the oxygen and nitrogen components of groundwater. I looked at groundwater from a pristine site, a human impacted site, and Title V treated wastewater. All of the water

Vallino, Joseph J.

10

Chemical composition of cometary nuclei  

NASA Technical Reports Server (NTRS)

Observational evidence pertaining to the origin and composition of cometary material is reviewed. Arguments favoring the undifferentiated character of the icy conglomerate are summarized. Theoretical descriptions of the sublimation of a cometary nucleus and the velocity field of the expanding gas are presented and compared with observations. The nature of cometary dust and the atomic abundances of H, C, N, O, and S in the volatile fraction are examined, and data on the dust and volatile fractions are combined to derive elemental abundances. It is shown that O, N, and S in cometary nuclei appear to have essentially cosmic abundances but that both H and C are drastically depleted with respect to the cosmic abundances. The apparent depletion of C by a factor of more than three is discussed. It is suggested that the missing carbon might be hidden in the dust fraction in the form of heavy organic molecules or might have remained in either the primeval solar nebula or interstellar space.

Delsemme, A. H.

1982-01-01

11

Environmental effects of oilfield chemicals on composite  

SciTech Connect

This paper presents a feasibility study of the effects of oilfield chemicals on composite materials. In this initial study only hydrochloric acid is considered. Initial attempts were made to test stressed specimens, but results were very poor. Subsequent testing was performed to determine how the composite material constituents reacted to the hydrochloric acid. The initial testing was performed on tubular specimens with axial and essentially hoop wound fibers of different materials with different resins. The specimens were loaded in bending to induce representative strains in the tubing. All specimens failed. The second tests consisted of only an environmental soak to determine the amount of mass uptake as well as the reduction in strength. The strength reduction results will be presented at a later time. Testing was performed on S-2 glass, carbon and Kevlar 49 as well as three different resins.

Sorem, R.M. [Univ. of Kansas, Lawrence, KS (United States). Dept. of Mechanical Engineering

1998-12-31

12

CHEMICAL AND RADIOCHEMICAL COMPOSITION OF THE RONGELAPESE DIET  

Microsoft Academic Search

The gross chemical composition of the Rongelapese diet indicates that it ; is low in fat, protein, and ash but fairly high in carbohydrate. The variation ; in gross chemical composition of the diets examined may be accounted for hy the ; broad variability of the different diets. The habitat of the Rongelapese ; probably does not demand a high-energy

DIPTIMAN CHAKRAVARTI; EDWARD E. HELD

1963-01-01

13

On-line chemical composition analyzer development  

SciTech Connect

The energy consumed in distillation processes in the United States represents nearly three percent of the total national energy consumption. If effective control of distillation columns can be accomplished, it has been estimated that it would result in a reduction in the national energy consumption of 0.3%. Real-time control based on mixture composition could achieve these savings. However, the major distillation processes represent diverse applications and at present there does not exist a proven on-line chemical composition sensor technology which can be used to control these diverse processes in real-time. This report presents a summary of the findings of the second phase of a three phase effort undertaken to develop an on-line real-time measurement and control system utilizing Raman spectroscopy. A prototype instrument system has been constructed utilizing a Perkin Elmer 1700 Spectrometer, a diode pumped YAG laser, two three axis positioning systems, a process sample cell land a personal computer. This system has been successfully tested using industrially supplied process samples to establish its performance. Also, continued application development was undertaken during this Phase of the program using both the spontaneous Raman and Surface-enhanced Raman modes of operation. The study was performed for the US Department of Energy, Office of Industrial Technologies, whose mission is to conduct cost-shared R D for new high-risk, high-payoff industrial energy conservation technologies. Although this document contains references to individual manufacturers and their products, the opinions expressed on the products reported do not necessarily reflect the position of the Department of Energy.

Roberts, M.J.; Garrison, A.A.; Muly, E.C.; Moore, C.F.

1992-02-01

14

Chemical composition of Desulfovibrio desulfuricans lipid A  

PubMed Central

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica. PMID:20978743

Lodowska, Jolanta; Jaworska-Kik, Marzena; Kurkiewicz, S?awomir; W?glarz, Ludmi?a; Dzier?ewicz, Zofia

2010-01-01

15

Chemical composition analysis and authentication of whisky.  

PubMed

Whisky (whiskey) is one of the most popular spirit-based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV-Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k-NN and CA, as well as preparation techniques such SPME or SPE. © 2014 Society of Chemical Industry. PMID:25315338

Wi?niewska, Paulina; Dymerski, Tomasz; Wardencki, Waldemar; Namie?nik, Jacek

2014-10-15

16

FUNDAMENTAL PARAMETERS AND CHEMICAL COMPOSITION OF ARCTURUS  

SciTech Connect

We derive a self-consistent set of atmospheric parameters and abundances of 17 elements for the red giant star Arcturus: T{sub eff} = 4286 {+-} 30 K, log g = 1.66 {+-} 0.05, and [Fe/H] = -0.52 {+-} 0.04. The effective temperature was determined using model atmosphere fits to the observed spectral energy distribution from the blue to the mid-infrared (0.44 to 10 {mu}m). The surface gravity was calculated using the trigonometric parallax of the star and stellar evolution models. A differential abundance analysis relative to the solar spectrum allowed us to derive iron abundances from equivalent width measurements of 37 Fe I and 9 Fe II lines, unblended in the spectra of both Arcturus and the Sun; the [Fe/H] value adopted is derived from Fe I lines. We also determine the mass, radius, and age of Arcturus: M = 1.08 {+-} 0.06 M{sub Sun }, R = 25.4 {+-} 0.2 R{sub Sun }, and {tau} = 7.1{sup +1.5}{sub -1.2} Gyr. Finally, abundances of the following elements are measured from an equivalent width analysis of atomic features: C, O, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, and Zn. We find the chemical composition of Arcturus typical of that of a local thick-disk star, consistent with its kinematics.

Ramirez, I. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Allende Prieto, C., E-mail: ivan@obs.carnegiescience.edu, E-mail: callende@iac.es [Instituto de Astrofisica de Canarias, 38205 La Laguna, Tenerife (Spain)

2011-12-20

17

Chemical compositions of large cluster IDPs  

SciTech Connect

We performed X-ray fluorescence spectroscopy on two large cluster IDPs, which sample the IDP parent body at a mass scale two orders-of-magnitude larger than {approx}10 {micro}m IDPs, allowing proper incorporation of larger mineral grains into the bulk composition of the parent body. We previously determined that {approx}10 {micro}m interplanetary dust particles (IDPs) collected from the Earth's stratosphere are enriched in many moderately volatile elements by a factor of {approx}3 over the CI meteorites. However, these IDP measurements provide no direct constraint on the bulk chemical composition of the parent body (or parent bodies) of the IDPs. Collisions are believed to be the major mechanism for dust production by the asteroids, producing dust by surface erosion, cratering and catastrophic disruption. Hypervelocity impact experiments at {approx}5 km/sec, which is the mean collision velocity in the main belt, performed by Flynn and Durda on ordinary chondrite meteorites and the carbonaceous chondrite meteorite Allende show that the 10 {micro}m debris is dominated by matrix material while the debris larger than {approx}25 {micro}m is dominated by chondrule fragments. Thus, if the IDP parent body is similar in structure to the chondritic meteorites, it is likely that the {approx}10 {micro}m IDPs oversample the fine-grained component of the parent body. We have examined the matrix material from the few meteorites that are sufficiently fine-grained to be samples of potential IDP parent bodies. This search has, thus far, not produced a compositional and mineralogical match to either the hydrous or anhydrous IDPs. This result, coupled with our recent mapping of the element distributions, which indicates the enrichment of moderately volatile elements is not due to contamination on their surfaces, suggests the IDPs represent a new type of extraterrestrial material. Nonetheless, the meteorite fragmentation results suggest that compositional measurements on 10 {micro}m IDPs only provide a direct constraint on the bulk chemical composition of the IDP parent body if the size-scale of the grains in the parent body is <<10 {micro}m. The stratospheric collections include many nonchondritic, mono-mineralic grains, collected along with the fine-grained chondritic IDPs. Some of these grains, which include volatile-poor olivine and pyroxene as well as calcophile-rich sulfides, have fine-grained, chondritic material (i.e., small bits of typical IDPs) adhering to their surfaces. This indicates that at least some of the non-chondritic grains found on the stratospheric collectors are fragments from the same parent as the fine-grained IDPs. Thus, the bulk composition of the IDP parent body can only be reconstructed by adding to the fine-grained, chondritic IDPs the correct amount of this non-chondritic material. Qualitatively, the addition of olivines and pyroxenes will reduce the mean content of many moderately volatile elements while the addition of sulfides will increase the content of some of these elements. However, the quantitative task of adding these monomineralic grains to the fine-grained IDPs cannot be accomplished by simply adding the non-chondritic material in proportion to its occurrence on the stratospheric collectors because: (1) it is not clear that all of the olivines, pyroxenes, sulfides or other mineral grains found on the stratospheric collectors are extraterrestrial; (2) the settling rate of a particle depends on its density and shape, thus the concentration factor for these high-density, mono-mineralic grains is lower at the collection altitude than it is for the lower-density, fine-grained aggregate IDPs; and (3) the atmospheric entry survival of a particle is a function of density, so higher density grains (e.g., sulfides) are more likely to vaporize on entry, even if they enter with the same velocity as fine-grained, lower-density aggregates. The collection of 'cluster IDPs,' which enter the atmosphere as large particles, some larger than 50 {micro}m in diameter, containing both fine-grained aggregate material

Flynn, G.J.; Lanzirotti, A.; Sutton, S.R. (SUNYP); (UC)

2006-12-06

18

Ethylene vinylacetate copolymer and nanographite composite as chemical vapour sensor  

NASA Astrophysics Data System (ADS)

Polymer-nanostructured carbon composite as chemical vapour sensor is described, made by the dissolution method of a non-conductive polymer, ethylene vinylacetate copolymer, mixed with conductive nanographite particles (carbon black). Sensor exhibits relative electrical resistance change in chemical vapours, like ethanol and toluene. Since the sensor is relatively cheap, easy to fabricate, it can be used in air quality monitoring and at industries to control hazardous substance concentration in the air, for example, to protect workers from exposure to chemical spills.

Stepina, Santa; Sakale, Gita; Knite, Maris

2013-12-01

19

Characterization of Stem Growth and Chemical Composition in Sorghum Bicolor  

E-print Network

Sorghum bicolor is a subtropical grass grown throughout the world for human consumption, animal feed and for the growing biofuels industry. In this thesis I characterize sorghum stem growth and chemical composition, and identify QTL and candidate...

Anderson Jr, Robert Taylor

2014-03-31

20

Functional composite materials based on chemically converted graphene.  

PubMed

Graphene, a one-atom layer of graphite, possesses a unique two-dimensional structure and excellent mechanical, thermal, and electrical properties. Thus, it has been regarded as an important component for making various functional composite materials. Graphene can be prepared through physical, chemical and electrochemical approaches. Among them, chemical methods were tested to be effective for producing chemically converted graphene (CCG) from various precursors (such as graphite, carbon nanotubes, and polymers) in large scale and at low costs. Therefore, CCG is more suitable for synthesizing high-performance graphene based composites. In this progress report, we review the recent advancements in the studies of the composites of CCG and small molecules, polymers, inorganic nanoparticles or other carbon nanomaterials. The methodology for preparing CCG and its composites has been summarized. The applications of CCG-based functional composite materials are also discussed. PMID:21360763

Bai, Hua; Li, Chun; Shi, Gaoquan

2011-03-01

21

The Chemical Composition of Praesepe (M44)  

NASA Astrophysics Data System (ADS)

Star clusters have long been used to illuminate both stellar evolution and Galactic evolution. They also hold clues to the chemical and nucleosynthetic processes throughout the history of the Galaxy. We have taken high signal-to-noise (S/N), high-resolution spectra of 11 solar-type stars in the Praesepe open cluster to determine the chemical abundances of 16 elements: Li, C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, Y, and Ba. We have determined Fe from Fe I and Fe II lines and find [Fe/H] = +0.12 ±0.04. We find that Li decreases with temperature due to increasing Li depletion in cooler stars; it matches the Li-temperature pattern found in the Hyades. The [C/Fe] and [O/Fe] abundances are below solar and lower than the field star samples due to the younger age of Praesepe (0.7 Gyr) than the field stars. The alpha-elements, Mg, Si, Ca, and Ti, have solar ratios with respect to Fe, and are also lower than the field star samples. The Fe-peak elements, Cr and Ni, track Fe and have solar values. The neutron capture element [Y/Fe] is found to be solar, but [Ba/Fe] is enhanced relative to solar and to the field stars. Three Praesepe giants were studied by Carrera and Pancino; they are apparently enhanced in Na, Mg, and Ba relative to the Praesepe dwarfs. The Na enhancement may indicate proton-capture nucleosynthesis in the Ne ? Na cycling with dredge-up into the atmospheres of the red giants.

Boesgaard, Ann Merchant; Roper, Brian W.; Lum, Michael G.

2013-09-01

22

THE CHEMICAL COMPOSITION OF PRAESEPE (M44)  

SciTech Connect

Star clusters have long been used to illuminate both stellar evolution and Galactic evolution. They also hold clues to the chemical and nucleosynthetic processes throughout the history of the Galaxy. We have taken high signal-to-noise (S/N), high-resolution spectra of 11 solar-type stars in the Praesepe open cluster to determine the chemical abundances of 16 elements: Li, C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, Y, and Ba. We have determined Fe from Fe I and Fe II lines and find [Fe/H] = +0.12 ±0.04. We find that Li decreases with temperature due to increasing Li depletion in cooler stars; it matches the Li-temperature pattern found in the Hyades. The [C/Fe] and [O/Fe] abundances are below solar and lower than the field star samples due to the younger age of Praesepe (0.7 Gyr) than the field stars. The alpha-elements, Mg, Si, Ca, and Ti, have solar ratios with respect to Fe, and are also lower than the field star samples. The Fe-peak elements, Cr and Ni, track Fe and have solar values. The neutron capture element [Y/Fe] is found to be solar, but [Ba/Fe] is enhanced relative to solar and to the field stars. Three Praesepe giants were studied by Carrera and Pancino; they are apparently enhanced in Na, Mg, and Ba relative to the Praesepe dwarfs. The Na enhancement may indicate proton-capture nucleosynthesis in the Ne ? Na cycling with dredge-up into the atmospheres of the red giants.

Boesgaard, Ann Merchant; Roper, Brian W.; Lum, Michael G., E-mail: boes@ifa.hawaii.edu, E-mail: brianwroper@gmail.com, E-mail: mikelum@ifa.hawaii.edu [Visiting astronomer, W. M. Keck Observatory jointly operated by the California Institute of Technology and the University of California. (United States)

2013-09-20

23

Chemical evolution of galaxies. I. A composition-dependent SPH model for chemical evolution and cooling  

E-print Network

We describe an SPH model for chemical enrichment and radiative cooling in cosmological simulations of structure formation. This model includes: i) the delayed gas restitution from stars by means of a probabilistic approach designed to reduce the statistical noise and, hence, to allow for the study of the inner chemical structure of objects with moderately high numbers of particles; ii) the full dependence of metal production on the detailed chemical composition of stellar particles by using, for the first time in SPH codes, the Qij matrix formalism that relates each nucleosynthetic product to its sources; and iii) the full dependence of radiative cooling on the detailed chemical composition of gas particles, achieved through a fast algorithm using a new metallicity parameter zeta(T) that gives the weight of each element on the total cooling function. The resolution effects and the results obtained from this SPH chemical model have been tested by comparing its predictions in different problems with known theoretical solutions. We also present some preliminary results on the chemical properties of elliptical galaxies found in self-consistent cosmological simulations. Such simulations show that the above zeta-cooling method is important to prevent an overestimation of the metallicity-dependent cooling rate, whereas the Qij formalism is important to prevent a significant underestimation of the [alpha/Fe] ratio in simulated galaxy-like objects.

Francisco J. Martínez-Serrano; Arturo Serna; Rosa Domínguez-Tenreiro; Mercedes Mollá

2008-04-23

24

The relationship of argon retentivity and chemical composition of hornblende  

Microsoft Academic Search

K-Ar ages of 26 hornblende separates from Connemara, western Ireland do not show any correlation with the chemical composition of the hornblendes, including their iron contents. It is suggested that this is the usual pattern as there are only rare reports of compositional control of K-Ar ages.

Bernard E. Leake; Elias M. Elias; Colin M. Farrow

1988-01-01

25

Chemical analysis of a field-failed composite suspension insulator  

Microsoft Academic Search

The purpose of this research is to establish the type of corrosive environment responsible for brittle fracture of suspension composite insulators. A series of Fourier transform infrared spectroscopy (FTIR) experiments has been performed to identify chemical functionalities formed during the degradation process of composite insulators affected by brittle fracture. It has been shown that the brittle fracture process is caused

Abdul R. Chughtai; Dwight M. Smith; Maciej S. Kumosa

1998-01-01

26

Chemical composition in relation with biomass ash structure  

NASA Astrophysics Data System (ADS)

Biomass combustion can be more complicated like combustion of fossil fuels because it is necessary to solve problems with lower ash melting temperature. It can cause a lot of problems during combustion process. Chemical composition of biomass ash has great impact on sinters and slags creation in ash because it affects structure of heated ash. In this paper was solved relation between chemical composition and structure of heated ash from three types of biomass (spruce wood, miscanthus giganteus and wheat straw). Amount of SiO2, CaO, MgO, Al2O3 and K2O was determined. Structure of heated ash was optically determined after heating to 1000 °C or 1200 °C. Results demonstrated that chemical composition has strong effect on structure and color of heated ash.

Holubcik, Michal; Jandacka, Jozef

2014-08-01

27

Correlation between biogas yield and chemical composition of energy crops.  

PubMed

The scope of this study was to investigate the influence of the chemical composition of energy crops on biogas and methane yield. In total, 41 different plants were analyzed in batch test and their chemical composition was determined. For acid detergent lignin (ADL) content below 10% of total solids, a significant negative correlation for biogas and methane yields (r?-0.90) was observed. Based on a simple regression analysis, more than 80% of the sample variation can be explained through ADL. Based on a principal component analysis and multiple regression analysis, ADL and hemicellulose are suggested as suitable model variables for biogas yield potential predictions across plant species. PMID:25443623

Dandikas, V; Heuwinkel, H; Lichti, F; Drewes, J E; Koch, K

2014-12-01

28

Cyanobacterial chemical warfare affects zooplankton community composition  

Microsoft Academic Search

SUMMARY 1. Toxic algal blooms widely affect our use of water resources both with respect to drinking water and recreation. However, it is not only humans, but also organisms living in freshwater and marine ecosystems that may be affected by algal toxins. 2. In order to assess if cyanobacterial toxins affect the composition of natural zooplankton communities, we quantified the

LARS-ANDERS HANSSON; SUSANNE GUSTAFSSON; KARIN RENGEFORS; LINA BOMARK

2007-01-01

29

Energetic composites and method of providing chemical energy  

DOEpatents

A method is described for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application. 3 figs.

Danen, W.C.; Martin, J.A.

1997-02-25

30

Energetic composites and method of providing chemical energy  

DOEpatents

A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

Danen, Wayne C. (Los Alamos, NM); Martin, Joe A. (Espanola, NM)

1997-01-01

31

Chemical composition of Cystoseira crinita Bory from the Eastern Mediterranean.  

PubMed

The chemical composition of the brown alga Cystoseira crinita Bory from the Eastern Mediterranean was investigated. Fourteen sterols have been identified, five of them for the first time in algae. The structure of one new sterol was established. The origin of seven sterols with short side chains was discussed. In the volatile fraction 19 compounds and in the polar fraction 15 compounds were identified. The main lipid classes were isolated and their fatty acid composition was established. PMID:12240980

Kamenarska, Zornitsa; Yalçin, Funda N; Ersöz, Tayfun; Cali?, Ihsan; Stefanov, Kamen; Popov, Simeon

2002-01-01

32

Chemical composition of cottonseed affected by cropping management practices  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cottonseed is a valuable raw material for a range of food, animal feed, and industrial (such as adhesives) products. Chemical composition is one of the critical parameters to evaluate cottonseed's quality and potential end use. However, the information on the impacts of cropping management practices...

33

Regulating continent growth and composition by chemical weathering  

E-print Network

Regulating continent growth and composition by chemical weathering Cin-Ty Aeolus Lee* , Douglas M, and approved January 28, 2008 (received for review November 25, 2007) Continents ride high above the ocean, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during

Lee, Cin-Ty Aeolus

34

The Chemical Composition of Some Mediterranean Citrus Oils  

Microsoft Academic Search

To compare the regional variations of the quantitative chemical composition, some Mediterranean citrus oils (lemon, sweet orange, bitter orange, and mandarin) from Italy and Spain have been studied. Over 100 constituents were identified in the various oils, from which 80 components could be quantified.No significant differences were found in the concentrations of the main constituents of sweet orange oils from

Mans H. Boelens; Rafael Jimenez

1989-01-01

35

Chemical composition of acid rains in the Venezuelan savannah region  

Microsoft Academic Search

The chemical composition of rain events has been determined at 6 sites in the Venezuelan savannah region. The results indicate that precipitations are little affected by anthropogenic emissions and that rain concentrations of anions and cations are similar to those observed at \\

E. Sanhueza; M. C. Arias; L. Donoso; N. Graterol; M. Hermoso; I. Martí; J. Romero; A. Rondón; M. Santana

1992-01-01

36

Chemical composition, antifungal and insecticidal activities of Hedychium essential oils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The antimicrobial properties of essential oils have been documented, and their use as “biocides” is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and cultivars were ...

37

Chemical Composition of Albanian Myrtle Oil (Myrtus communis L.)  

Microsoft Academic Search

Chemical composition of the essential oils obtained by hydrodistillation from Albanian wild growing myrtle leaves, flowers and ripe fruits was examined by GC\\/MS. Over one 100 compounds were detected in the oils, from which more than 40 could be identified. Significant differences were found in the concentrations of the main constituents of the oils, from varoius parts of the plant,

Uran Asllani

2000-01-01

38

Chemical Composition of Chlamydospores of Candida albicans  

PubMed Central

A variety of analytical techniques was employed to study the composition of the chlamydospore of Candida albicans. The outer, thin, electron-transparent layer was found to be composed of glucan, together with a small amount of chitin. The inner, thick, electron-dense layer is proteinaceous. The central structure is composed largely of ribonucleic acid and lipid globules. In addition to being acid-fast, the chlamydospore was found to contain glycolipids and to lose the property of acid-fastness on extraction with ethanol-ether. Images PMID:4099099

Jansons, Vilma K.; Nickerson, Walter J.

1970-01-01

39

Chemical composition of Hanford Tank SY-102  

SciTech Connect

The US Department of Energy established the Tank Waste Remediation System (TWRS) to safely manage and dispose of the radioactive waste, both current and future, stored in double-shell and single-shell tanks at the Hanford sites. One major program element in TWRS is pretreatment which was established to process the waste prior to disposal using the Hanford Waste Vitrification Plant. In support of this program, Los Alamos National Laboratory has developed a conceptual process flow sheet which will remediate the entire contents of a selected double-shelled underground waste tank, including supernatant and sludge, into forms that allow storage and final disposal in a safe, cost-effective and environmentally sound manner. The specific tank selected for remediation is 241-SY-102 located in the 200 West Area. As part of the flow sheet development effort, the composition of the tank was defined and documented. This database was built by examining the history of liquid waste transfers to the tank and by performing careful analysis of all of the analytical data that have been gathered during the tank`s lifetime. In order to more completely understand the variances in analytical results, material and charge balances were done to help define the chemistry of the various components in the tank. This methodology of defining the tank composition and the final results are documented in this report.

Birnbaum, E.; Agnew, S.; Jarvinen, G.; Yarbro, S.

1993-12-01

40

Chemical imaging of wood-polypropylene composites.  

PubMed

Recent investigations of wood plastic composites have revealed a detrimental effect of using lubricant systems in production. This includes nullifying part or all of the mechanical benefit of using a polar compatibilizer, maleic anhydride polypropylene (MAPP), in the composite formulation. This investigation utilizes lubricants labeled with deuterium in conjunction with Fourier transform infrared (FT-IR) spectroscopy to allow for the separation of individual lubricants from all other material constituents. All of the deuterium labeled lubricants, used without MAPP, revealed their expulsion from the wood interface during crystallization. MAPP coupling agent was found to exist near the wood, but it is unclear if any covalent bonding with the hydroxyl functionality on the wood surface occurred. The addition of zinc stearate lubricants appears to nullify the activity of the anhydride functionality near the wood surface as evidenced by a shift in the FT-IR spectra to the hydrolyzed form of the coupling agent. Most of the additives collect at the edges of the spherulites in mostly amorphous regions of the material. The consequence of this morphology may be a weak interface between crystallites. PMID:16925926

Harper, David P; Wolcott, Michael P

2006-08-01

41

Chemical composition and microstructure of Bauhinia grains.  

PubMed

Bauhinia is a leguminous plant species found in almost every part of the world, including southern Africa. In this study, grain composition and protein body microstructure of two indigenous southern African Bauhinia species, B. galpinii and B. petersiana were determined. Protein (38 g/100 g) and fat (23 g/100 g) were the major constituents of Bauhinia. Bauhinia grains also contained substantial amounts of zinc (6 mg/100 g) and iron (3 mg/100 g) when compared to FAO/WHO standards. The parenchyma cells of Bauhinia showed spherical protein bodies with globoids inclusions and these were surrounded by lipids. However, the protein bodies of B. petersiana were smaller in size (7?±?3 ?m) than those of B. galpinii (13?±?4 ?m). The microstructure of protein bodies in Bauhinia is very similar to that of soya, suggesting that the processing technology developed for soya protein may be adopted for Bauhinia. PMID:25190895

Amonsou, Eric O; Siwela, Muthulisi; Dlamini, Nomusa

2014-09-01

42

Date fruit: chemical composition, nutritional and medicinal values, products.  

PubMed

Date fruit has served as a staple food in the Arab world for centuries. Worldwide production of date fruit has increased almost threefold over the last 40 years, reaching 7.68 million tons in 2010. Date fruit can provide many essential nutrients and potential health benefits to the consumer. Date fruit goes through four ripening stages named kimri, khalal, rutab and tamer. The main chemical components of date fruit include carbohydrates, dietary fibre, enzymes, protein, fat, minerals, vitamins, phenolic acids and carotenoids. The chemical composition of date fruit varies according to ripening stage, cultivar, growing environment, postharvest conditions, etc. The nutritional and medicinal activities of date fruit are related to its chemical composition. Many studies have shown that date fruit has antioxidant, antimutagenic, anti-inflammatory, gastroprotective, hepatoprotective, nephroprotective, anticancer and immunostimulant activities. Various date fruit-based products such as date syrup, date paste, date juice and their derived products are available. Date by-products can be used as raw materials for the production of value-added products such as organic acids, exopolysaccharides, antibiotics, date-flavoured probiotic-fermented dairy produce, bakery yeasts, etc. In this paper the chemical composition and nutritional and medicinal values of date fruit as well as date fruit-based products are reviewed. PMID:23553505

Tang, Zhen-Xing; Shi, Lu-E; Aleid, Salah M

2013-08-15

43

Chemical composition and antimicrobial activity of Polish herbhoneys.  

PubMed

The present study focuses on samples of Polish herbhoneys (HHs), their chemical composition and antimicrobial activity. A gas chromatography-mass spectrometry (GC-MS) method was used to analyse eight samples of herbal honeys and three samples of nectar honeys. Their antimicrobial activities were tested on selected Gram-positive (Bacillus cereus, Staphylococcus aureus, Staphylococcus schleiferi) and Gram-negative (Escherichia coli) bacteria, as well as on pathogenic fungi Candida albicans. Ether extracts of HHs showed significant differences in composition but the principal groups found in the extracts were phenolics and aliphatic hydroxy acids typical of royal jelly and unsaturated dicarboxylic acids. In spite of the differences in chemical composition, antimicrobial activity of the extracts of HHs against all the tested microorganisms except E. coli was observed. PMID:25308646

Isidorov, V A; Bagan, R; Bakier, S; Swiecicka, I

2015-03-15

44

Apparatus for rapid measurement of aerosol bulk chemical composition  

DOEpatents

An apparatus and method for continuous on-line measurement of chemical composition of aerosol particles with a fast time resolution are provided. The apparatus includes a modified particle size magnifier for producing activated aerosol particles and a collection device which collects the activated aerosol particles into a liquid stream for quantitative analysis by analytical methods. The method provided for on-line measurement of chemical composition of aerosol particles includes exposing aerosol carrying sample air to hot saturated steam thereby forming activated aerosol particles; collecting the activated aerosol particles by a collection device for delivery as a jet stream onto an impaction surface; flushing off the activated aerosol particles from the impaction surface into a liquid stream for delivery of the collected liquid stream to an analytical instrument for quantitative measurement.

Lee, Yin-Nan E. (East Setauket, NY); Weber, Rodney J. (Atlanta, GA)

2003-01-01

45

Lemon Balm ( Melissa officinalis ) Stalk: Chemical Composition and Fiber Morphology  

Microsoft Academic Search

This work investigates the potentials of lemon balm (Melissa officinalis L.) stalk (LBS), a massive waste part of medicinal plant, for pulp and papermaking by assessing its fiber characteristics\\u000a and chemical composition. In addition, LBS properties were compared with some important agro-residues such as bagasse stalk\\u000a (BS), cotton stalk (CS) and tobacco stalk (TS). There is no information about suitability

Yahya Hamzeh; Fatemeh Amani

2011-01-01

46

Chemical Composition of Galactic Cosmic Rays with Space Experiments  

E-print Network

The origin and properties of the cosmic radiation are one of the most intriguing question in modern astrophysics. The precise measurement of the chemical composition and energy spectra of the cosmic rays provides fundamental insight into these subjects. In this paper we will review the existing experimental data. Specifically, we will analyse results collected by space-born experiments discussing the experimental uncertainties and challenges with a focus on the PAMELA experiment.

Mirko Boezio; Emiliano Mocchiutti

2012-08-07

47

Chemical composition of essential oil from Calligonum polygonoides Linn  

Microsoft Academic Search

The essential oil from air dried buds and roots of Calligonum polygonoides Linn., has been extracted from dry steam distillation and analysed for chemical composition by gas chromatography–mass spectrometry. In total, 27 and 10 compounds were analysed qualitatively and quantitatively, accounting for 68.42% and 82.12% total contents of the essential oils of buds and roots, respectively. It contains a complex

Muhammad Qasim Samejo; Shahabuddin Memon; Muhammad Iqbal Bhanger; Khalid Mohammed Khan

2012-01-01

48

Carbon Nano Tube Composites with Chemically Functionalized Plant Oils  

NASA Astrophysics Data System (ADS)

Carbon Nano Tube Composites with Chemically Functionalized Plant Oil Wim Thielemans, R., P. Wool, V. Barron and W. Blau Multi-Wall Carbon Nano Tubes (MWCNT) made by the Kratchmer-Huffman CCVD process were found to interact and solubilize by slow mechanical stirring, with chemically functionalized plant oils, such as acrylated, epoxidized and maleinated triglycerides (TG) derived from plant oils. The chemical functionality on the TG imparted amphiphilic properties to the oils which allows them to self-assemble on the nanotubes, promoting both dissolution and the ability to make nanocomposites with unusual properties. Once in solution, the MWCT can be processed in a variety of methods, in particular to make composites with enhanced mechanical, fracture and thermal properties. Since the tensile modulus of MWs is about 1 TPa and a vector percolation analysis indicated tensile strengths of 50-100 GPa, we obtain significantly improved properties with even small amounts (1-3the glass transition temperature of the composite by about 20 oC, and the tensile modulus by about 11significant effects on the fracture stress can be obtained due to the both the influence of the strength and length of the MWNT at the crack tip. The ability of the oils to self-assemble on the carbon nanotube surfaces also makes them ideal candidates for self-healing materials. The properties with different functionalized oils will be reported. Supported by EPA, DoE and ISF

Thielemans, Wim; Wool, Richard P.; Blau, Werner; Barron, Valerie

2003-03-01

49

The density of volatile bearing melts in the Earth's deep mantle: The role of chemical composition  

E-print Network

The density of volatile bearing melts in the Earth's deep mantle: The role of chemical composition 2009 Keywords: Silicate melts Chemical composition Water Mg# Density Equation of state Density in the mantle. We study the role of chemical composition on melt density based on the ideal-mixing model

50

Development of chemical vapor composites, CVC materials. Final report  

SciTech Connect

Industry has a critical need for high-temperature operable ceramic composites that are strong, non-brittle, light weight, and corrosion resistant. Improvements in energy efficiency, reduced emissions and increased productivity can be achieved in many industrial processes with ceramic composites if the reaction temperature and pressure are increased. Ceramic composites offer the potential to meet these material requirements in a variety of industrial applications. However, their use is often restricted by high cost. The Chemical Vapor composite, CVC, process can reduce the high costs and multiple fabrication steps presently required for ceramic fabrication. CVC deposition has the potential to eliminate many difficult processing problems and greatly increase fabrication rates for composites. With CVC, the manufacturing process can control the composites` density, microstructure and composition during growth. The CVC process: can grow or deposit material 100 times faster than conventional techniques; does not require an expensive woven preform to infiltrate; can use high modulus fibers that cannot be woven into a preform; can deposit composites to tolerances of less than 0.025 mm on one surface without further machining.

NONE

1998-10-05

51

Hospital Admissions and Chemical Composition of Fine Particle Air Pollution  

PubMed Central

Rationale: There are unexplained geographical and seasonal differences in the short-term effects of fine particulate matter (PM2.5) on human health. The hypothesis has been advanced to include the possibility that such differences might be due to variations in the PM2.5 chemical composition, but evidence supporting this hypothesis is lacking. Objectives: To examine whether variation in the relative risks (RR) of hospitalization associated with ambient exposure to PM2.5 total mass reflects differences in PM2.5 chemical composition. Methods: We linked two national datasets by county and by season: (1) long-term average concentrations of PM2.5 chemical components for 2000–2005 and (2) RRs of cardiovascular and respiratory hospitalizations for persons 65 years or older associated with a 10-?g/m3 increase in PM2.5 total mass on the same day for 106 U.S. counties for 1999 through 2005. Measurements and Main Results: We found a positive and statistically significant association between county-specific estimates of the short-term effects of PM2.5 on cardiovascular and respiratory hospitalizations and county-specific levels of vanadium, elemental carbon, or nickel PM2.5 content. Conclusions: Communities with higher PM2.5 content of nickel, vanadium, and elemental carbon and/or their related sources were found to have higher risk of hospitalizations associated with short-term exposure to PM2.5. PMID:19299499

Bell, Michelle L.; Ebisu, Keita; Peng, Roger D.; Samet, Jonathan M.; Dominici, Francesca

2009-01-01

52

Predicting hygroscopic growth using single particle chemical composition estimates  

NASA Astrophysics Data System (ADS)

particle mass spectral data, collected in Paris, France, have been used to predict hygroscopic growth at the single particle level. The mass fractions of black carbon, organic aerosol, ammonium, nitrate, and sulphate present in each particle were estimated using a combination of single particle mass spectrometer and bulk aerosol chemical composition measurements. The Zdanovskii-Stokes-Robinson (ZSR) approach was then applied to predict hygroscopic growth factors based on these mass fraction estimates. Smaller particles with high black carbon mass fractions and low inorganic ion mass fractions exhibited the lowest predicted growth factors, while larger particles with high inorganic ion mass fractions exhibited the highest growth factors. Growth factors were calculated for subsaturated relative humidity (90%) to enable comparison with hygroscopic tandem differential mobility analyzer measurements. Mean predicted and measured hygroscopic growth factors for 110, 165, and 265 nm particles were found to agree within 6%. Single particle-based ZSR hygroscopicity estimates offer an advantage over bulk aerosol composition-based hygroscopicity estimates by providing additional chemical mixing state information. External mixing can be determined for particles of a given diameter through examination of the predicted hygroscopic growth factor distributions. Using this approach, 110 nm and 265 nm particles were found to be predominantly internally mixed; however, external mixing of 165 nm particles was observed periodically when thinly coated and thickly coated black carbon particles were simultaneously detected. Single particle-resolved chemical information will be useful for modeling efforts aimed at constraining cloud condensation nuclei activity and hygroscopic growth.

Healy, Robert M.; Evans, Greg J.; Murphy, Michael; Jurányi, Zsófia; Tritscher, Torsten; Laborde, Marie; Weingartner, Ernest; Gysel, Martin; Poulain, Laurent; Kamilli, Katharina A.; Wiedensohler, Alfred; O'Connor, Ian P.; McGillicuddy, Eoin; Sodeau, John R.; Wenger, John C.

2014-08-01

53

Chemical geodynamics  

Microsoft Academic Search

Consideration is given to the following three principal boundary conditions relating to the nature and development of chemical structure in the earth's mantle: (1) inferred scale lengths for mantle chemical heterogeneities, (2) interrelationships of the various isotopic tracers, and (3) the bulk composition of the earth. These boundary conditions are integrated with geophysical constraints in order to evaluate models for

A. Zindler; S. R. Hart

1986-01-01

54

On the chemical composition of Titan's dry lakebed evaporites  

E-print Network

Titan, the main satellite of Saturn, has an active cycle of methane in its troposphere. Among other evidence for a mechanism of evaporation at work on the ground, dry lakebeds have been discovered. Recent Cassini infrared observations of these empty lakes have revealed a surface composition poor in water ice compared to that of the surrounding terrains --- suggesting the existence of organic evaporites deposits. The chemical composition of these possible evaporites is unknown. In this paper, we study evaporite composition using a model that treats both organic solids dissolution and solvent evaporation. Our results suggest the possibility of large abundances of butane and acetylene in the lake evaporites. However, due to uncertainties of the employed theory, these determinations have to be confirmed by laboratory experiments.

Cordier, Daniel; Ferreira, Abel

2013-01-01

55

Chem I Supplement: The Chemical Composition of the Cell.  

ERIC Educational Resources Information Center

Describes the principal chemical substances which occur in most cells. These chemicals are the lipids, carbohydrates, proteins, and nucleic acids. Suggests that the structures of these substances be taught first since structure determines function. (JN)

Holum, John R.

1984-01-01

56

The physical and chemical composition of the lower mantle.  

PubMed

This article reviews some of the recent advances made within the field of mineral physics. In order to link the observed seismic and density structures of the lower mantle with a particular mineral composition, knowledge of the thermodynamic properties of the candidate materials is required. Determining which compositional model best matches the observed data is difficult because of the wide variety of possible mineral structures and compositions. State-of-the-art experimental and analytical techniques have pushed forward our knowledge of mineral physics, yet certain properties, such as the elastic properties of lower mantle minerals at high pressures and temperatures, are difficult to determine experimentally and remain elusive. Fortunately, computational techniques are now sufficiently advanced to enable the prediction of these properties in a self-consistent manner, but more results are required.A fundamental question is whether or not the upper and lower mantles are mixing. Traditional models that involve chemically separate upper and lower mantles cannot yet be ruled out despite recent conflicting seismological evidence showing that subducting slabs penetrate deep into the lower mantle and that chemically distinct layers are, therefore, unlikely.Recent seismic tomography studies giving three-dimensional models of the seismic wave velocities in the Earth also base their interpretations on the thermodynamic properties of minerals. These studies reveal heterogeneous velocity and density anomalies in the lower mantle, which are difficult to reconcile with mineral physics data. PMID:16286292

Bovolo, C Isabella

2005-12-15

57

Values below detection limit in compositional chemical data.  

PubMed

Samples representing part of a whole, usually called compositional data in statistics, are commonplace in analytical chemistry--say chemical data in percentage, ppm, or ?g g(-1). Their distinctive feature is that there is an inherent relationship between all the analytes constituting a chemical sample as they only convey relative information. Some compositional data analysis principles and the log-ratio based methodology are outlined here in practical terms. Besides, one often finds that some analytes are not present in sufficient concentration in a sample to allow the measuring instruments to effectively detect them. These non-detects are usually labelled as "compositional data determines any data analysis and demands for a specialised treatment of less-thans that, unfortunately, is not usually covered in chemometrics. Some well-founded statistical methods are revisited in this paper aiming to prevent practitioners from relying on popular but untrustworthy approaches. A new proposal to estimate less-thans combining a log-normal probability model and a multiplicative modification of the samples is also introduced. Their performance is illustrated and compared on a real data set, and guidelines are provided for practitioners. Matlab and R code implementing the methods are made available for the reader. PMID:23374212

Palarea-Albaladejo, J; Martín-Fernández, J A

2013-02-18

58

Unusual chemical compositions of noctilucent-cloud particle nuclei  

NASA Technical Reports Server (NTRS)

Two sounding rocket payloads were launched from the ESRO range in Sweden during a noctilucent cloud display. Large numbers of submicron particles were collected, most of which appear to be made up of a high density material coated with a low density material. Typical electron micrographs are shown. Particle chemical compositions have been measured by use of dispersive X-ray analysis equipment attached to an electron microscope and have revealed that most of the high density particle nuclei have atomic weights greater than iron.

Hemenway, C. L.

1973-01-01

59

Chemical composition and thermal property of cuttlefish ( Sepia pharaonis) muscle  

Microsoft Academic Search

The chemical composition and thermal property of cuttlefish (Sepia pharaonis) muscle were studied. The head and mantle contained 11.9–14.9% protein, 0.5% fat, 1.2–1.3% ash, and 0.6–1.8% collagen. Lipids from the head and mantle contained phospholipid as the major component (78.6–87.8% of total lipid), with 10.6–19.5% diglyceride. Polyunsaturated fatty acids constituted 50.3–54.9% of fatty acids with a high content of DHA

Amonrat Thanonkaew; Soottawat Benjakul; Wonnop Visessanguan

2006-01-01

60

VEGA Mission results and chemical composition of Venusian clouds  

NASA Astrophysics Data System (ADS)

Physical and chemical analyses of the clouds and atmosphere of Venus on the basis of Vega payload data have yielded a cloud-particle composition in which the presence of phosphoric acid straightforwardly accounts for the fact that the clouds extend down to the 33-km limit of Vega's spectrometric, nephelometric, and photometric instrumentation. Attention is given to the problem posed by the inconsistency of these results with the much lower or entirely absent phosphorus at other Venera and Pioneer Venus landing probe sites. P4O6 is the main phosphorus-bearing gas.

Krasnopolsky, V. A.

1989-07-01

61

Measurements of the Chemical Composition of Atmospheric Nanoparticles  

NASA Astrophysics Data System (ADS)

The Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) is an instrument that is capable of measuring the chemical composition of particles as small as 4 nm. It accomplishes this with a sensitivity that makes it possible to measure the molecular composition of nanoparticles at ambient concentrations in the atmosphere. For the past five years, the TDCIMS has been performing measurements of the smallest particles in the atmosphere in order to determine the chemical species and mechanisms responsible for the growth of aerosols formed by nucleation. In this talk I will summarize what we've learned from these measurements, which took place in urban areas (Atlanta and Mexico City), a remote location (the boreal forests of Finland), and regions that are combinations of both (Boulder). With the exception of one study in urban Atlanta, in which sulfur species were seen to dominate, most measurements indicate a crucial role played by organic species in the growth of atmospheric nanoparticles. Positive ion TDCIMS measurements in a variety of locations show the presence of methyl and dimethyl amines in particles as small as 8 nm. Other oxidized organics detected in positive ion TDCIMS measurements are presumed to be alcohols, aldehydes, or ketones. Negative ion TDCIMS measurements show the presence of multifunctional organics with carboxylic acid moieties. Laboratory studies using pure and multi-component aerosols are assisting us in identifying the many ions that were observed during our campaigns. Our measurements suggest that reactions of organic acids and organic bases on particle surfaces or within particles may form organic ions and/or salts in particles. Based on these measurements, we hypothesize that the organic salt formation mechanism may be the dominant mechanism by which nanoparticles grow in the atmosphere.

Smith, Jim

2008-03-01

62

Chemical composition of Titan's lakes and noble gases sequestration  

NASA Astrophysics Data System (ADS)

Titan is one of the most enigmatic objects in the Solar System. The presence of hydrocarbon lakes and even a global ocean have been suspected for decades. The dark features discovered by the CASSINI spacecraft are good candidates for these expected lakes (see McEwen et al. 2005 and Stofan et al. 2007). Their chemical composition has still not been measured but numerical models can give relatively accurate predictions. In the present work, we use the recent model of Titan's lakes chemical composition elaborated by Cordier et al. (2009) in light of the recent Cassini-Huygens measurements in order to investigate the possibility of sequestration of large quantities of noble gases in these liquids. Indeed, the noble gas abundances have been found to be largely in subsolar abundances in the atmosphere of Titan and the origin of this impoverishment is still poorly understood. Our preliminary results show that, under specific circumstances, at least the atmospheric depletion in krypton could be caused by its dissolution in the Titan's surface hydrocarbon liquid phase.

Cordier, D.; Mousis, O.; Lunine, J.-I.; Lavvas, P.; Lobo, L.; Ferreira, A.

2010-04-01

63

Switchgrass biomass and chemical composition for biofuel in eastern Canada  

SciTech Connect

Switchgrass (Panicum virgatum L.) is one of several warm-season grasses that have been identified as potential biomass crops in North America. A two-year field study was conducted, on a free-draining sandy clay loam (St. Bernard, Typic Hapludalf), to characterize the growth and evaluate changes in biomass accumulation and composition of switchgrass at Montreal, QC. Three cultivars, Cave-in-Rock, Pathfinder, and Sunburst, were grown in solid stands in a randomized complete block design. Canopy height, dry matter (DM) accumulation and chemical composition were monitored biweekly throughout the growing season. Average maximum canopy heights were 192.5 cm for Cave-in-Rock, 169.9 for Pathfinder, and 177.8 for Sunburst. The respective end-of-season DM yields were 12.2, 11.5, and 10.6 Mg/ha. Biomass production among cultivars appeared to be related to time of maturation. Nitrogen concentration of DM decreased curvilinearly from 25 g/kg at the beginning of the season to 5 g/kg DM at season's end. Both acid-detergent fiber (ADF) and neutral-detergent fiber (NDF) concentrations increased to a maximum early in the season, after which no changes were detected. The average maximum values of ADF and NDF were, respectively, 647.6 and 849.0 g/kg DM for Cave-in-Rock, 669.1 and 865.2 for Pathfinder, and 661.8 and 860.9 for Sunburst. Changes in canopy height, DM accumulation, and chemical composition could all be described by predictive regression equations. These results indicate that switchgrass has potential as a biomass crop in a short-season environment.

Madakadze, I.C.; Stewart, K.; Peterson, P.R.; Coulman, B.E.; Smith, D.L.

1999-08-01

64

Vector diagram of the chemical compositions of tektites and earth lavas  

NASA Technical Reports Server (NTRS)

The chemical compositions of tektites and various volcanic glasses, similar in composition to tektites are compared by a petrochemical method. The advantage of the method is that a large number of chemical analyses of igneous rocks can be graphically compared with the help of vectors, plotted in relation to six parameters. These parameters, calculated from ratios of the main oxides given by silicate analysis, reflect the chief characteristics of igneous rock. Material for the study was suppled by data from chemical analysis characterizing tektites of all known locations and data from chemical analyses of obsidians similar in chemical composition to tektites of various petrographical provinces.

Kvasha, L. G.; Gorshkov, G. S.

1978-01-01

65

Determining the chemical composition of cloud condensation nuclei  

SciTech Connect

This third progress report describes the status of our efforts to develop the instrumentation to collect cloud condensation nuclei (CCN) in amounts sufficient for chemical analysis. During the fall of 1992 we started collecting filter samples of CCN with the laboratory version of the apparatus at Rolla -MO. The mobile version of the apparatus is in the latter stages of construction. This report includes a fairly rigorous discussion of the operation of the CCN sampling system. A statistical model of the operation of the system is presented to show the ability of the system to collect CCN in the two different size ranges for which we plan to determine the chemical composition. A question is raised by the model results about the operation of one of the virtual impactors. It appears to pass a small percent of particles larger than its cut-point that has the potential of contaminating the smallest CCN sample with larger CCN material. Further tests are necessary, but it may be necessary to redesign that impactor. The appendices of the report show pictures of both the laboratory version and the mobile version of the CCN sampling system. The major hardware has been completed, and the mobile version will be in operation within a few weeks.

Williams, A.L.; Rothert, J.E.; McClure, K.E. (Illinois State Water Survey, Champaign, IL (United States)); Alofs, D.J.; Hagen, D.E.; Schmitt, J.; White, D.R.; Hopkins, A.R.; Trueblood, M.B. (Missouri Univ., Rolla, MO (United States). Cloud and Aerosol Science Lab.)

1992-12-01

66

Relation of sensory perception with chemical composition of bioprocessed lingonberry.  

PubMed

The impact of bioprocessing on lingonberry flavour was studied by sensory evaluation and chemical analysis (organic acids, mannitol, phenolic compounds, sugars and volatile compounds). Bioprocessing of lingonberries with enzymes, lactic acid bacteria (LAB) or yeast, or their combination (excluding pure LAB fermentation) affected their perceived flavour and chemical composition. Sweetness was associated especially with enzyme treatment but also with enzyme+LAB treatment. Yeast fermentation caused significant changes in volatile aroma compounds and perceived flavour, whereas minor changes were detected in LAB or enzyme-treated berries. Increased concentration of organic acids, ethanol and some phenolic acids correlated with perceived fermented odour/flavour in yeast fermentations, in which increase in benzoic acid level was significant. In enzymatic treatment decreasing anthocyanins correlated well with decreased perceived colour intensity. Enzyme treatment is a potential tool to decrease naturally acidic flavour of lingonberry. Fermentation, especially with yeast, could be an interesting new approach to increase the content of natural preservatives, such as antimicrobial benzoic acid. PMID:24679764

Viljanen, Kaarina; Heiniö, Raija-Liisa; Juvonen, Riikka; Kössö, Tuija; Puupponen-Pimiä, Riitta

2014-08-15

67

Chemical composition of rainwater in western Amazonia — Brazil  

NASA Astrophysics Data System (ADS)

An extensive sample study in western Amazonia, Brazil was performed over the course of one year to i) establish the natural influence of the forest, ii) determine the contribution of the vegetation and fossil fuel burning and iii) detect the geographical and temporal influences on the rainwater composition. Six sampling stations were chosen on two 1000 km-long orthogonal axes. Parintins, Itapiranga, Manaus, Tabatinga were the stations from East to West, and Boa Vista, Manaus, and Apui were the stations from North to South. The results indicate a complex control of the chemical composition of the rainwater and a rather high heterogeneity among the stations. This heterogeneity can be explained by the influence of biogenic, terrestrial dust, agriculture activities and biomass-burning aerosols, and the urban development of Manaus City with its rapid increase in the use of fossil fuel. The isotopic composition of the rainwater indicates that from the north and west sides to the south and east sides, a slight geographical and temporal gradient exists, and more ?180 enriched rainwater tends to be present in the west (Tabatinga) and in the North (Boa Vista). During the dry season a more negative ?180 rainwater was observed in Manaus and Boa Vista stations, as compared to others stations. This observation indicates the more intense evaporative contribution of rainwater as a consequence of a rapid deforestation (savannization) process in the Manaus region.

Honório, B. A. D.; Horbe, A. M. C.; Seyler, P.

2010-11-01

68

Morphology and chemical composition of Ag/Sn/Ag interconnections.  

PubMed

The main goal of the present contribution was to describe morphology and chemical composition of the intermetallic phases, which were formed during diffusion soldering process of the silver using tin. The Ag(3)Sn intermetallics is the main constituent of the joint after diffusion soldering at 235 degrees C and 265 degrees C. A closer inspection of the Ag/Ag(3)Sn interface revealed also the small crystallites of the second intermetallic phase, Ag(5)Sn, which was not previously observed using scanning electron microscope. Both phases are characterized by high melting temperatures: 480 degrees C and 724 degrees C, respectively. Therefore, their presence guarantees high thermal stability of the interconnection, which can be even three times higher than the temperature used for soldering. PMID:20500402

Skrzyniarz, P; Wojewoda-Budka, J; Wierzbicka-Miernik, A; Zieba, P

2010-03-01

69

Chemical Mechanical Planarization- Chemical  

NSDL National Science Digital Library

This website includes an animation which illustrates the chemical action of slurry in the chemical-mechanical planarization process. Objective: Explain the mechanical and chemical steps in the CMP process. This simulation is from Module 068 of the Process & Equipment III Cluster of the MATEC Module Library (MML). Find this animation under the section "Process & Equipment III." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey Phrase: MATEC Animation

2012-12-07

70

Chemical composition and structural features of the macromolecular components of Hibiscus cannabinus grown in Portugal  

Microsoft Academic Search

Different morphological regions of Hibiscus cannabinus plants grown in Portugal were submitted to chemical composition studies. General chemical composition was determined by established methods. The polysaccharides were fractionated by successive extractions of holocellulose with aqueous KOH solutions. The sugar composition was determined by hydrolysis of polysaccharides followed by gas chromatography (GC) analysis of neutral sugars and spectrophotometric determination of uronic

C. Pascoal Neto; A. Seca; D. Fradinho; M. A. Coimbra; F. Domingues; D. Evtuguin; A. Silvestre; J. A. S. Cavaleiro

1996-01-01

71

The chemical composition of the young, Inter-Cloud population  

NASA Astrophysics Data System (ADS)

High-resolution AAT spectroscopy and lower resolution spectrophotometry are presented for three early B-type stars that are members of the young, Inter-Cloud population between the Magellanic Clouds. These spectra have been analyzed using LTE model-atmosphere techniques, to derive the stellar atmospheric parameters and photospheric chemical compositions. The latter should reflect that of the present-day interstellar medium (ISM) within the Inter-Cloud Region (ICR). From a differential analysis, the three ICR stars appear to have a mean metal abundance of ~ 1.1 dex lower than their Population i Galactic analogues, and 0.5 dex lower than the SMC star (AV 304). Hence, the ICR gas does not reflect the present-day composition of either the SMC (or LMC) ISM. Age (and distance) estimates were obtained using the theoretical isochrones of Bertelli et al. (\\cite{ber94}); these imply that the young, Inter-Cloud population has an age dispersion of at least 10-40 Myr, and provide evidence for a distance gradient across the ICR. We discuss our results within the context of recent numerical simulations of the gravitational interactions between the Galaxy-LMC-SMC, that predict that the ICR was tidally disrupted from the SMC some 200 Myr ago. If the SMC was chemically homogeneous, a comparison of the ICR abundance determinations with the SMC age-metallicity relationship would then imply that the formation of the ICR must have occurred ~ 8.5 Gyr ago. Alternatively and more plausible, we postulate that the ICR gas formed from a mixture of SMC gas and an unenriched component. This is consistent with model-predictions that both a halo and disc component should have contributed to the material within the ICR during the tidal disruption.

Rolleston, W. R. J.; Dufton, P. L.; McErlean, N. D.; Venn, K. A.

1999-08-01

72

Chemical Threats  

MedlinePLUS

... indicate a chemical agent release. Before Before a Chemical Threat What you should do to prepare for ... and on the highest level. During During a Chemical Threat What you should do in a chemical ...

73

Chemical Emergencies  

MedlinePLUS

When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

74

Sensing of repair in chemically self-repairing composites  

NASA Astrophysics Data System (ADS)

The question to be answered in this paper is how "does a user determine if a chemical self repair system has succeeded in self repairing damage". Three sensing methods indicated that chemical has been released into damage areas, another four methods were used to indicate that the container or encapsulator had been broken to release repair chemical, but only one method is known to indicate that the chemical reaction of the repair chemical has been accomplished. Many other methods were used to assess the structural or dynamic efficacy of the repairs. These methods of sensing of repair action are detailed with experimental data and results. The novel and ground breaking method of determining repair efficacy receives most emphasis.

Dry, Carolyn

2014-04-01

75

XPS analysis of combustion aerosols for chemical composition, surface chemistry, and carbon chemical state.  

PubMed

Carbonaceous aerosols can vary in elemental content, surface chemistry, and carbon nano-structure. Each of these properties is related to the details of soot formation. Fuel source, combustion process (affecting formation and growth conditions), and postcombustion exhaust where oxidation occurs all contribute to the physical structure and surface chemistry of soot. Traditionally such physical and chemical parameters have been measured separately by various techniques. Presented here is the unified measurement of these characteristics using X-ray photoelectron spectroscopy (XPS). In the present study, XPS is applied to combustion soot collected from a diesel engine (running biodiesel and pump-grade fuels); jet engine; and institutional, plant, and residential oil-fired boilers. Elemental composition is mapped by a survey scan over a broad energy range. Surface chemistry and carbon nanostructure are quantified by deconvolution of high-resolution scans over the C1s region. This combination of parameters forms a distinct matrix of identifiers for the soots from these sources. PMID:21322576

Vander Wal, Randy L; Bryg, Vicky M; Hays, Michael D

2011-03-15

76

RIVER TRANSPORT - INDUCED CHANGES IN CHEMICAL COMPOSITION OF ALLUVIAL GOLD (DOCUMENTED ON LOCALITIES THE WESTERN CARPATHIANS)  

Microsoft Academic Search

Alluvial gold is influenced by various physical, chemical and biological factors. As type- localities for study of changes in chemical composition of alluvial gold we chose Pukanec (Central Slovakia Neovolcanic Field) and Magurka and Ni?ná Boca (Nízke Tatry Mts). The most distinctive are morphological and chemical changes (dissolution and precipitation), the latter is most commonly represented by the formation of

B. BAHNA; A. SMIRNOV; M. CHOVAN; F. BAKOS

77

Chemical composition of bioactive pressurized extracts of Romanian aromatic plants.  

PubMed

In this contribution, pressurized liquid extraction (PLE) has been employed to isolate bioactive compounds from three native Romanian plants, oregano (Origanum vulgare), tarragon (Artemisia dracunculus) and wild thyme (Thymus serpyllum). Different PLE conditions have been tested including extraction with water, ethanol and their mixtures in a wide range of extraction temperatures (50-200°C), and the antioxidant capacity of the extracts was measured using different assays (DPPH radical scavenging, TEAC assay and Folin-Ciocalteau assay to measure total phenols). Moreover, a complete chemical characterization by using LC-MS/MS was carried out to be able to correlate the bioactivity with the particular chemical composition of each extract and plant. The use of PLE with water as a solvent at the highest temperature tested (200°C) always provided the highest extraction yields for the three studied plants, being maximum for oregano (>60%). Besides, oregano's pressurized water extracts at lower temperatures (50°C) presented the highest content on total phenols (184.9 mg gallic acid/g extract) and the best antioxidant activities (EC(50) 6.98 ?g/ml). In general, oregano extracts were the most active, followed by wild thyme extracts. The antioxidant capacity measured by DPPH assay was highly correlated with the amount of total phenols. Moreover, the use of a LC-MS/MS method allowed the identification of 30 different phenolic compounds in the different extracts, including phenolic acids, flavones, flavanones and flavonols, which have an important influence on the total antioxidant capacity of the different extracts. PMID:21163488

Miron, T L; Plaza, M; Bahrim, G; Ibáñez, E; Herrero, M

2011-07-29

78

Simulating Organic Aerosol over Europe: Concentration, Chemical Composition and Sources  

NASA Astrophysics Data System (ADS)

A 3-D Chemical Transport Model was applied over Europe to simulate the concentration and chemical composition of organic aerosol during the months of May 2008, March 2009, July 2009 and January 2010. PMCAMx-2008 includes the recently developed volatility basis set framework to describe OA absorptive partitioning by organizing the total OA mass into surrogates along an axis of volatility. We evaluate the performance of the model against AMS measurements taken during the above periods from various sites in Europe. The model predictions are also compared against the Positive Matrix Factorization analysis of AMS observations. The model predicts that fresh primary OA is a small contributor to organic PM concentrations in Europe, and that oxygenated species (oxidized primary and biogenic secondary) dominate the ambient OA. The Mediterranean region is the only area in Europe where sulfate concentrations are predicted to be much higher than the OA during the late spring period. The model performance against the high time resolution AMS measurements is encouraging. The model tends to predict relatively flat diurnal profiles for PM1 OA in many areas, both rural and urban in agreement with the available measurements. During the winter the model performs reasonably well at most sites, however both the model results and the measurements point towards missing wood-burning emissions in the inventories used, mostly in Scandinavia and East Germany. During the July 2009 and January 2010 periods, we applied the two-way nesting of PMCAMx-2008 with special focus over 4 Megacities in Europe in which a higher grid resolution was used. The importance of horizontal grid resolution for the description of chemical transformations in Megacities was analyzed. The improvement in the reproduction of the observations at the urban scale of the PM1 OC and EC during the summer is modest. During the winter the improvement is more significant, although the major reasons of the differences between the model predictions and observations in both seasons are not due to the modelling scale used, but to other problems (meteorology, emissions, process description, etc.).

Fountoukis, C.; Megaritis, A.; Charalampidis, P. E.; van der Gon, H. D.; Pilinis, C.; Pandis, S. N.

2012-04-01

79

Chemical composition of sedimentary rocks in California and Hawaii  

USGS Publications Warehouse

A compilation of published chemical analyses of sedimentary rocks of the United States was undertaken by the U.S. Geological Survey in 1952 to make available scattered data that are needed for a wide range of economic and scientific uses. About 20,000-25,000 chemical analyses of sedimentary rocks in the United States have been published. This report brings together 2,312 of these analyses from California and Hawaii. The samples are arranged by general lithologic characteristics and locality. Indexes of stratigraphy, rock name, commercial uses, and minor elements are provided. The sedimentary rocks are classified into groups and into categories according to the chemical analyses. The groups (A through F2) are defined by a system similar to that proposed by Brian Mason in 1952, in which the main parameters are the three major components of sedimentary rocks: (1) uncombined silica, (2) clay (R203 ? 3Si02 ? nH20), and (3) calcium-magnesium carbonate. The categories are based on the degree of admixture of these three major components with other components, such as sulfate, phos- phate, and iron oxide. Common-rock, mixed-rock, and special-rock categories apply to rocks consisting of 85 percent or more, 50-84 percent, and less than 49 percent, respectively, of the three major components combined. Maps show distribution of sample localities by States; triangular diagrams show the lithologic characteristics and classification groups. Cumulative-frequency curves of each constituent in each classification group of the common-rock and mixed-rock categories are also included. The numerous analyses may not adequately represent the geochemical nature of the rock types and formations of the region because of sampling bias. Maps showing distribution of sample localities indicate that many of the localities are in areas where, for economic or other reasons, special problems attracted interest. Most of the analyzed rocks tended to be fairly simple in composition - mainly mixtures of just two of the three major components or a mixture of these and a fourth component such as phosphate, gypsum, or iron oxide.

Hill, Thelma P., (compiler)

1981-01-01

80

Exploring the chemical composition of water in the Kandalaksha Bay  

NASA Astrophysics Data System (ADS)

Oil films were noted at the head of the Kandalaksha Bay as far back as in 1971, as soon as the first stage of the oil tank farm had been commissioned (the autumn of 1970). In 1997-1998 there were accidental oil spills posing a real threat to the Kandalaksha Reserve biota. In May 2011, oil spills from the Belomorsk oil tank farm resulted in a local environmental emergency. In this work we have traced the evolution of polluted water by means of hydrogeochemical monitoring and reconstructing the chemical composition of surface and near-bottom water of the Kandalaksha Bay by using physical-chemical modeling (Selector software package, Chudnenko, 2010). The surface and near-bottom water was sampled in the summer of 2012 and 2013 at the following sites: under the numbers 3 (N 67.2.673, E 32.23.753); 4 (N 67.3.349, E 32.28.152); 1 (N 67.5.907, E 32.29.779), and 2 (N 67.6.429, E 32.30.539). The monitored objects and sampling time were sensitive to both the effects of the White Sea water (high tide), fresh water, and water affected by human impact (the oil tank farm). At each site, three samples were taken. The next stage involved reconstructing of the sea water ion composition by modeling within the Al-B-Br-Ar-He-Ne-C-Ca-Cl-F-K-Mg-Mn-N-Na-P-S-Si-Sr-Cu-Zn-H-O-e system, where e is an electron. Modeling of the chemical composition of near-bottom water (site 3) has revealed high contents of carbon dioxide, hydrogen disulphide, hydrocarbonates, and no oxygen (Eh<0). All this suggests a transformation of hydrocarbons that might have got to the sampling area in May 2011, or as the result of constant leakage of petroleum hydrocarbons from the oil tank farm. Sampling at site 4 in 2013 has revealed petroleum hydrocarbons both in surface (0.09 mg/l) and near-bottom (0.1 mg/l) water. Both monitoring and modeling have demonstrated that hydrobionts on areas adjoining the oil tank farm are far from prospering. Monitoring should be accompanied by express analysis of oxidizing conditions in both the soil and near-bottom water. Since the water contamination in the White Sea has lasted for decades, it is necessary to examine the near-bottom water, in particular in its deeper areas, to reveal the possible accumulation and destruction of organic substances at the sea floor. It is evident that an unbiased assessment of the environmental situation can be obtained by involving all kinds of information processing technologies.

Mazukhina, Svetlana; Masloboev, Vladimir; Chudnenko, Konstantin; Khaitov, Vadim; Maksimova, Victoria; Belkina, Natalia

2014-05-01

81

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

Microsoft Academic Search

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46?S, 64°05?W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium,

T. P. DeFelice

1998-01-01

82

Chemical Composition and Insecticidal Properties of Thymus numidicus (Poiret) Essential Oil from Algeria  

E-print Network

Chemical Composition and Insecticidal Properties of Thymus numidicus (Poiret) Essential Oil from-Industrielles'', 17042 La Rochelle, France Abstract: Essential oils of thyme (Thymus numidicus (Poiret)) from Algeria of linalool and thymol. Key Words: Thyme oil, Thymus numidicus (Poiret), chemical composition, insecticidal

Paris-Sud XI, Université de

83

Chemical Composition and Antioxidant Activities of Broussonetia papyrifera Fruits  

PubMed Central

Fruits of Broussonetia papyrifera from South China were analyzed for their total chemical composition, and antioxidant activities in ethanol and aqueous extracts. In the fruit of this plant, the crude protein, crude fat and carbohydrates was 7.08%, 3.72% and 64.73% of dry weight, respectively. The crude protein, crude fat and carbohydrates were 15.71%, 20.51% and 36.09% of dry weight, respectively. Fatty acid and amino acid composition of the fruit were analyzed. Unsaturated fatty acid concentration was 70.6% of the total fatty acids. The percentage of the essential amino acids (EAAs) was 40.60% of the total amino acids. Furthermore, B. papyrifera fruit are rich in many mineral elements and vitamins. Total phenolic content was assessed using the Folin-Ciocalteau assay, whereas antioxidant activities were assessed by measuring the ability of the two extracts to scavenge DPPH radicals, inhibit peroxidation, and chelate ferric ions. Their reducing power was also assessed. Results indicated that the aqueous extract of B. papyrifera was a more potent reducing agent and radical-scavenger than the ethanol extract. GC–MS analysis of the ethanol extract showed the presence of some acid-containing compounds. The changes in total phenolic content and antioxidant capacity in B. papyrifera from four different regions grown under normal conditions were assessed. The antioxidant activity of different extracts was positively associated with their total phenolic content. These results suggest that the fruit of B. papyrifera could be used in dietary supplement preparations, or as a food additive, for nutritional gain, or to prevent oxidation in food products. PMID:22389678

Sun, Jie; Liu, Shao-fang; Zhang, Chu-shu; Yu, Li-na; Bi, Jie; Zhu, Feng; Yang, Qing-li

2012-01-01

84

The chemical composition and distribution of interstellar grains  

NASA Technical Reports Server (NTRS)

The chemical composition of interstellar grains is derived here on the basis of (1) the cosmic abundance of the elements; (2) the wavelength dependence of extinction and polarization; (3) the average total extinction; (4) the ratio of polarization to extinction; (5) the predominantly dielectric character of grains in the visible spectral region; and (6) infrared spectral characteristics of grains. Inferences of the core-mantle model with respect to spatial distribution are consistent with the proposition that growth of the mantles occurs in the galactic shock region predicted by the density-wave theory. Estimates of the total visual extinction toward the galactic center and the consequent estimates of the total amount of far infrared radiation are shown to depend critically on the grain model. Variations of the ratio of far ultraviolet to visual extinction are correlated with the conditions for growth of mantles on the bare small particles which are generally prevented from accreting mantles primarily because of their extreme temperature fluctuations produced by the ultraviolet photons in the radiation field.

Greenberg, J. M.; Hong, S.-S.

1974-01-01

85

[Chemical composition of three Mexican strains of mushrooms (Pleurotus ostratus)].  

PubMed

The chemical composition of three Mexican strains of Pleurotus ostreatus (INIREB-8, CDBB-H-896 and CDBB-H-897), were determined. The mushrooms were cultivated on wheat straw in a greenhouse (22-28 degrees C temperature and 80 +/- 5% of relative humidity). Fruits bodies of P. ostreatus contained (all values are expressed in g/100 g dry wt.), protein (N x 6.25): 24.64 +/- 0.21-28.50 +/- 0.26; lipids: 1.10 +/- 0.16-1.85 +/- 0.22; mineral matter: 7.66 +/- 0.23-8.79 +/- 0.25; dietary fibre: 32.14 +/- 0.14-36.81 +/- 0.40; and available carbohydrates: 26.33 +/- 1.04-30.46 +/- 0.21. They contain vitamins (mg/100 g dry wt): riboflavin: 3.31-3.7, thiamin: 1.92-1.96, niacin: 35.98-36.56 and ascorbic acid: 28-35. The main fatty acid was linoleic (0.70-1.19 g/100 g dry wt), it was also reported a low calcium and phosphorus content. Concluding the Pleurotus ostreatus could be a source of some of the complex B vitamins, dietary fiber, protein and linoleic acid. PMID:10347703

Bautista Justo, M; Alanís Guzmán, M G; González de Mejía, E; García Díaz, C L

1998-12-01

86

Chemical Composition and Biological Activity of the Centipeda minima (Asteraceae).  

PubMed

The antimicrobial activity of the Centipeda minima L. (Asteraceae) extract was evaluated against seven microorganisms using the disc diffusion method. The extract showed a broad spectrum of antimicrobial activity against all the tested bacterial strains, especially Enterobacter aerogenes, Klebsiella pneumonia, Staphylococcus aureus and Yersinia enterocolitica. The chemical composition of the extract obtained from Centipeda minima was analysed by GC-MS. Twentythree compounds, constituting about 84.75 % of the total extract, were identified. The main constituents were palmitic acid (7.47%), (Z,Z)-9-,12-octadecatrienoic acid (6.52%), (Z,Z,Z)-9-,12-octadecatrienoic acid (7.01%), phytol (7.01%), naptho[2.3-b]furan-2-(3H)-on (6.21%), 1-(1,2,3,4,7,7a-hexahydro-1,4,4,5-tetramethyl-1,3a-ethano-3aH-inden-6-yl)etanon (7.95%), 1,3,5-tri-tertbutyl- benzene (4.52%), (3Z)-2-methyl-3-octen-2-ol (5.95%) and artemisia ketone (4.98%). The extract was also tested against brine shrimp for toxicity. There was no significant toxicity as it only recorded a LC50 value of 4.92 mg/ml. The study shows that the extract is a good antimicrobial agent with potential applications in public health against diseases. PMID:22692191

Soetardjo, Surjani; Jong, Poh Chan; Ahmad, Mohamad Noor; Lachimanan, Yoga Latha; Sreenivasan, Sasidharan

2007-03-01

87

Chemical composition, antifungal and insecticidal activities of Hedychium essential oils.  

PubMed

The antimicrobial properties of essential oils have been documented, and their use as "biocides" is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and cultivars were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. The antifungal and insecticidal activities of these oils were tested against Colletotrichum acutatum, C. fragariae, and C. gloeosporioides, and three insects, the azalea lace bug (Stephanitis pyrioides), the yellow fever mosquito (Aedes aegypti), and the red imported fire ant (Solenopsis invicta). Hedychium oils were rich in monoterpenes and sesquiterpenes, especially 1,8-cineole (0.1%-42%), linalool (<0.1%-56%), a-pinene (3%-17%), b-pinene (4%-31%), and (E)-nerolidol (0.1%-20%). Hedychium oils had no antifungal effect on C. gloeosporioides, C. fragariae, and C. acutatum, but most Hedychium oils effectively killed azalea lace bugs. The oils also show promise as an adult mosquito repellent, but they would make rather poor larvicides or adulticides for mosquito control. Hedychium oils acted either as a fire ant repellent or attractant, depending on plant genotype and oil concentration. PMID:23579997

Sakhanokho, Hamidou F; Sampson, Blair J; Tabanca, Nurhayat; Wedge, David E; Demirci, Betul; Baser, Kemal Husnu Can; Bernier, Ulrich R; Tsikolia, Maia; Agramonte, Natasha M; Becnel, James J; Chen, Jian; Rajasekaran, Kanniah; Spiers, James M

2013-01-01

88

Chemical composition of acid rains in the Venezuelan savannah region  

NASA Astrophysics Data System (ADS)

The chemical composition of rain events has been determined at 6 sites in the Venezuelan savannah region. The results indicate that precipitations are little affected by anthropogenic emissions and that rain concentrations of anions and cations are similar to those observed at "remote" continental sites. At each location, the rain is acidic with average pHs ranging from 4.4 to 5.4. Over 50% of the free acidity may be due to formic and acetic acids. HNO3 and H2SO4 contribute only less than 36%. NH3 plays a significant role as neutralizing compound; Ca and Mg carbonates may also, in some cases, reduce the acidity of the rain solution. A complete evaluation of the ions that take part in the acid-base equilibrium is given. The participation of organic acid is discussed in detail. The first rains of the season, during biomass burning periods, are heavily loaded with several compounds, showing that emissions and/or atmospheric production are enhanced during vegetation fires. No significant variation in rain acidity was observed; it is likely that the larger atmospheric photochemical formation of organic and inorganic acids during burning is neutralized by a large primary emission of NH3. The study of these "particular" rains is useful in searching for pollutants emitted by fires and/or possible atmospheric processes that may occur in the associated haze layer.

Sanhueza, E.; Arias, M. C.; Donoso, L.; Graterol, N.; Hermoso, M.; Martí, I.; Romero, J.; Rondón, A.; Santana, M.

1992-02-01

89

Comparing Chemical Compositions of Dwarf Elliptical Galaxies and Globular Clusters  

NASA Astrophysics Data System (ADS)

Because of their abundance in cluster environments and fragility due to their low mass, dwarf elliptical galaxies (dEs) are excellent specimens for studying the physical processes that occur inside galaxy clusters. These studies can be used to expand our understanding of the process of galaxy (specifically dE) formation and the role of dark matter in the Universe. To move closer to better understanding these topics, we present a study of the relationship between dEs and globular clusters (GCs) by using the largest sample of dEs and GC satellites to date. We focus on comparing the ages and chemical compositions of dE nuclei with those of satellite GCs by analyzing absorption lines in their spectra. To better view the spectral features of these relatively dim objects, we employ a spectral co-addition process, where we add the fluxes of several objects to produce a single spectrum with high signal-to-noise ratio. Our finding that dE nuclei are younger and more metal rich than globular clusters establishes important benchmarks that future dE formation theories will consider. We also establish a means to identify GCs whose parent galaxies are uncertain, which allows us to make comparisons between this GC group and the satellite GCs.

Chu, Jason; Sparkman, Lea; Toloba, Elisa; Guhathakurta, Puragra

2015-01-01

90

Brazilian kefir: structure, microbial communities and chemical composition  

PubMed Central

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml. PMID:24031681

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-01-01

91

The Chemical Composition of Fogs and Clouds in Southern California.  

NASA Astrophysics Data System (ADS)

Fog and clouds are frequent occurrences in Southern California. Their chemical composition is of interest due to their potential role in the transformation of sulfur and nitrogen oxides to sulfuric and nitric acid and in the subsequent deposition of those acids. In addition, cloud and fog droplets may be involved in the chemistry of low-molecular-weight carboxylic acids and carbonyl compounds. The major inorganic species in cloud and fogwater samples were NH_4^+, H ^+, NO_3^-, and SO_4^{2-}. Concentrations in fogwater samples were 1-10 times 10^ {-3} M; pH values ranged from ~eq2 to 6. Nitrate usually exceeded sulfate. Acidity depended on the availability of of NH_3 from agricultural operations. Stratus cloudwater had somewhat lower concentrations; pH values were in the range 3-4. The major factors accounting for variation in fog- or cloudwater composition were the preexisting aerosol and gas concentrations and variations in liquid water content. Deposition and entrainment or advection of different air masses were also important during extended cloud or fog episodes. The droplet size dependence of cloudwater composition was investigated on one occasion in an intercepted coastal stratus clouds. The observations were consistent with the hypothesis that small droplets form on small secondary aerosol composed of H_2SO _4, HNO_3, and their NH_4^+ salts, while large droplets form on large sea-salt and soil-dust aerosol. Species that can exist in the gas phase, such as HCl and HNO _3, may be found in either droplet-size fraction. Concentrations of S(IV) and CH_2 O in the range 100-1000 ?m were observed in fogwater from urban sites in Southern California. Lower concentrations were observed in stratus clouds. The high levels of S(IV) and CH_2 O were attributed to the formation of hydroxymethanesulfonate (HMSA), the S(IV) adduct of CH_2O. Direct measurement of HMSA in fogwater samples from Bakersfield, CA were made by ion-pairing chromatography. Glyoxal and methylglyoxal were observed at concentrations comparable to CH_2O in fogwater samples from Riverside, CA and in stratus cloudwater samples from sites along the Santa Barbara Channel.

Munger, James William

92

Chemical Equations  

NSDL National Science Digital Library

It discusses the process of equation writing and balancing chemical equations in perspective of the chemical changes that take place during a reaction. This module is the third in a series on chemical reactions.

Carpi, Anthony

2003-03-27

93

Chemical composition of Antrim shale in the Michigan basin  

SciTech Connect

During the period between March 1977 and July 1980 core samples from 28 different wells at various locations in the Antrim shale deposit in the Michigan Basin were analyzed for Al, SiO/sub 2/, Fe, Mg, Ca, Na, S, Pb, Hg, Ba, Sb, Sn, Cd, Ag, Mo, Sr, Br, As, Zn, Cu, Ni, Co, Mn, Cr, V, Sc, Cl, P, F, B, Be, and Li. The geochemical analysis revealed that the sulfur content of the shale varied proportionately with that of carbon. On the other hand, calcium values vary inversely with organic carbon (lowest calcite in shale with highest organic carbon). Iron values do not vary greatly within a core and show no tendency to follow organic carbon or sulfur. It seems that the relationships that exist between the chemical species are controlled by the geological events that resulted in the formation of the shale. The kerogen was found to be a crosslinked polymeric structure consisting of roughly equal amounts of aromatic and aliphatic carbons. Functional groups are few, mainly hydroxy and olefinic double bonds. The bitumen (toluene extractable material) was fractionated and the fractions identified. The paraffins in the samples had the same constituents in differing concentrations while the aromatic fractions appear to have significant differences in composition. The distribution of the n-alkanes indicates the shale is more mature than the Green River shales. The amount of vanadyl porphyrin is greater than the amount of nickel and the ratio increases with depth. The concentration of petroporphyrins ranged from one-tenth to one-third the amount extracted from western oil shales.

Leddy, D.G.; Sandel, V.R.; Swartz, G.L.; Kenny, D.H.; Gulick, W.M.; El Khadem, H.S.

1980-08-01

94

Chemical composition of atmospheric precipitation in the northwestern United States  

Microsoft Academic Search

Data from sampling stations in the Northeastern United States show that atmosperic precipitation in this region is composed of a dilute calcium-hydrogen sulfate water having additional sodium and chloride near the coast. In the inland and coastal sections, excepting only the highly industrialized areas, variations among the precipitation chemical loads measured at various sites show no systematic differences that suggest

F. J. Jr. Pearson; D. W. Fisher

1971-01-01

95

The Chemical Composition of Local Group Dwarf Spheroidals  

E-print Network

I will review the progress of VLT spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies. This spectroscopy has allowed us to obtain detailed insights into the chemical and dynamical properties of the resolved stellar population in these nearby systems.

Eline Tolstoy

2005-06-21

96

Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse  

USGS Publications Warehouse

Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions with rain water or water used in street washing and fire fighting. Chemical leach tests using deionized water as the extraction fluid show the dust samples can be quite alkaline, due primarily to reactions with calcium hydroxide in concrete particles. Calcium and sulfate are the most soluble components in the dust, but many other elements are also readily leached, including metals such as Al, Sb, Mo Cr, Cu, and Zn. Indoor dust samples produce leachates with higher pH, alkalinity, and dissolved solids than outdoor dust samples, suggesting most outdoor dust had reacted with water and atmospheric carbon dioxide prior to sample collection. Leach tests using simulated lung fluids as the extracting fluid suggest that the dust might also be quite reactive in fluids lining the respiratory tract, resulting in dissolution of some particles and possible precipitation of new phases such as phosphates, carbonates, and silicates. Results of these chemical characterization studies can be used by health scientists as they continue to track and interpret health effects resulting from the short-term exposure to the initial dust cloud and the longer-term exposure to dusts resuspended during cleanup.

Plumlee, Geoffrey S.; Hageman, Philip L.; Lamothe, Paul J.; Ziegler, Thomas L.; Meeker, Gregory P.; Theodorakos, Peter M.; Brownfield, Isabelle; Adams, Monique G.; Swayze, Gregg A.; Hoefen, Todd M.; Taggart, Joseph E.; Clark, Roger N.; Wilson, S.; Sutley, Stephen J.

2009-01-01

97

Frost flower chemical composition during growth and its implications for aerosol production  

E-print Network

Frost flower chemical composition during growth and its implications for aerosol production; published 5 November 2008. [1] Frost flowers have been proposed to be the major source of sea-salt aerosol. Therefore, we chemically analyzed 28 samples of frost flowers and parts of frost flowers collected from sea

Douglas, Thomas A.

98

Chemometric Survey of Italian Bottled Mineral Waters by Means of their Labelled Physicochemical and Chemical Composition  

Microsoft Academic Search

Bottled mineral waters (132 samples) from 19 districts of Italy were characterized by means of the physico-chemical and chemical composition (30 parameters) reported on their label by using statistical analysis. Bottled waters showed a lack of homogeneity in the type of parameters reported in the label, the level of aluminium being reported by only five brands. The relationships among 12

Andrea Versari; Giuseppina Paola Parpinello; Sergio Galassi

2002-01-01

99

Polarity parameters and dynamic mechanical behaviour of chemically modified banana fiber reinforced polyester composites  

Microsoft Academic Search

Natural fibers are replacing synthetic fibers as reinforcement in various matrices. The composites so prepared can effectively be used as a substitute for wood and also in various other technical fields like automobile parts. However, to improve the adhesion between the fiber and matrix, chemical modification is suggested. The effect of chemical modification on the dynamic mechanical properties of banana

Laly A. Pothan; Sabu Thomas

2003-01-01

100

Chemical composition and origin of the Acapulco meteorite  

NASA Astrophysics Data System (ADS)

New chemical data for both whole-rock and individual mineral samples from the Acapulco meteorite are reported. Results of instrumental neutron activation analysis (INAA) of bulk samples show large variation in La, Cr, Se, and Fe contents reflecting inhomogeneous distribution of the corresponding host phases: phosphate, chromite, sulfide, and FeNi metal. In contrast, Mn, Sc, and Na contents are uniformly distributed reflecting constant fractions of orthopyroxene, olivine, and plagioclase in bulk samples. INAA data were obtained on single olivine and orthopyroxene grains with numerous tiny metal inclusions. The siderophile elements in these inclusions, in particular the low Ir contents, suggest that the inclusions formed by partial melting of matrix metal. The composition of the metal inclusions and the absence of such inclusions in clinopyroxene suggests an upper limit of about 20% partial melting of Acapulco at around 1200°C. During melting and closed-system crystallization the inhomogeneous distribution of metal, chromite, sulfide, and phosphates was established. Acapulco phosphates are of igneous origin. Most of them were not formed by oxidation of metal. The uniform K contents of bulk Acapulco samples and the comparatively high contents of volatiles (including rare gases) in bulk samples demonstrate a closed-system behavior. Neither loss nor gain of volatile elements has occurred. Ion microprobe data of rare earth elements (REEs) in Acapulco minerals show an equilibrium distribution for heavy REEs and nonequilibrium for light REEs. Bulk Acapulco samples have large excesses of light REEs and U with phosphates being the major carrier. Absolute REE contents of phosphates are variable. The observed enrichments of REEs and U in bulk Acapulco samples cannot be explained by the addition of phosphates, since the approximately chondritic ratios of Ca/Mg and P/Mg exclude major gains of Ca and P through the addition of phosphates. It is suggested that a fluid phase rich in incompatible elements infiltrated Acapulco and that REEs and U were extracted by phosphates. The remaining fluid phase subsequently must have drained away. From temperatures determined by two-pyroxene equilibria, spinel-olivine and Ca zonation in olivine, a thermal history of Acapulco is constructed. Cooling rates at 900°C of about 100 K/Ma are estimated. The concentration profiles of Ca in olivine, showing constant Ca throughout grain interiors and sharp decreases at the rims, are difficult to explain. If the Ca zonation in olivine exclusively reflects cooling, slow cooling must have been followed by fast cooling at temperatures below 650°C. Alternatively, the low Ca contents of olivine rims may reflect other processes, such as, for example, formation of phosphates. A model for the evolution of Acapulco is presented: The parent body of Acapulco accreted earlier than that of the ordinary chondrites (OC), thus more 26Al was available for heating, leading to higher peak temperatures than in OC. Extensive solid state equilibration at 900°C completely erased the 26Mg signature in plagioclase. Acapulco is, despite the absence of chondrules, essentially a chondritic meteorite, attesting to the variety of planetesimals of chondritic composition in the asteroid belt.

Zipfel, J.; Palme, H.; Kennedy, A. K.; Hutcheon, I. D.

1995-09-01

101

Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods - slides  

EPA Science Inventory

Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

102

Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods  

EPA Science Inventory

Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

103

Absolute parameters and chemical composition of the binary star OU Gem  

NASA Astrophysics Data System (ADS)

The absolute parameters and chemical composition of the BY Dra-type spectroscopic binary OU Gem (HD 45088) were determined on the basis of 10 high-resolution spectra. A new orbital solution of the binary system was determined, the binary ephemerides were specified, and the main physical and atmospheric parameters of the binary components were obtained. The chemical composition of both components was estimated for the first time for the stars of such type.

Glazunova, L. V.; Mishenina, T. V.; Soubiran, C.; Kovtyukh, V. V.

2014-10-01

104

Rapid, Contactless and Non-Destructive Testing of Chemical Composition of Samples  

NASA Astrophysics Data System (ADS)

Our results demonstrate that a new effect can be induced in each solid in a wide spectral range of electromagnetic irradiation. In the present manuscript we prove experimentally that one of the possible applications of this effect is for an express contactless control of the chemical composition of a series of samples, in this case, coins. The method has wide applicability ranging from defense and homeland security to several applications requiring rapid and nondestructive identification of chemical composition.

Ivanov, O.; Vaseashta, A.; Stoychev, L.

105

Willow leaf and periphyton chemical composition, and the feeding preferences of Olinga feredayi (Trichoptera: Conoesucidae)  

Microsoft Academic Search

The chemical composition of autumn?shed willow (Salix fragilis) leaves was examined over a 56?day period of immersion in a stream, and compared with the chemical composition of periphyton. Much of the carbohydrates, phenolic compounds, and tannins were leached from the leaves within the first week. Nitrogen and chlorophyll a concentrations increased as a percentage of ash?free dry mass throughout the

Philip J. Lester; Stuart F. Mitchell; D. Scott

1994-01-01

106

Chemical and fatty acid composition of Cyperus esculentus  

Microsoft Academic Search

The physical and chemical properties of chufa tubers are given in Table 1. The nuts were found to be rich in oil (21.57%), fiber (22.13%), and protein (8.11%). Previous studied reported 932.8 g\\/kg dry matter, 245 g\\/kg crude lipid, 256.8 g\\/kg starch, 14.3 g\\/kg ash, 50.5 g\\/kg protein, 89.1 g\\/kg crude fibre, and 154.3 g\\/kg total sugar [3]. The fatty

M. M. Ozcan; A. Gumuscu; F. Er; D. Arslan; B. Ozkalp

2010-01-01

107

The Chemical Composition of Carbon C(N) stars  

E-print Network

A chemical study of normal Galactic C(N) carbon stars is presented. Abundances of Li, CNO isotopes and s-elements are derived. The derived abundances of s-elements nicely agree with theoretical s-process nucleosynthesis predictions during the AGB phase. However, the figures obtained for Li and the 12C/13C ratios might imply the existence of a non-standard mixing process during the AGB phase operating preferentially in low mass stars. The intrinsic or extrinsic nature of C(N) stars is also discussed.

C. Abia; I. Dominguez; R. Gallino; S. Masera; M. Busso; O. Straniero; P. de Laverny; B. Plez

2003-02-14

108

Chemical Composition of Atmospheric Aerosols in Iowa City  

NASA Astrophysics Data System (ADS)

In this study, the seasonal and spatial variability of chemical components in atmospheric PM2.5 were investigated in Iowa City, Iowa for the first time. Daily PM samples were collected from 25 August to 10 November 2011 at two sites in Iowa City (West and East) that were separated by approximately four miles. During this time, daily average PM2.5 mass concentrations ranged from 3 - 26 ?g m-3, within attainment of EPA National Ambient Air Quality Standard of 35 ?g m-3. The average PM2.5 concentration was 11.2×4.9 ?g m-3 (arithmetic mean × one standard deviation for n = 72). Carbonaceous aerosol (elemental carbon and organic matter) was the dominant component of PM2.5, contributing 40% of PM2.5 mass. Another 30% was due to water soluble inorganic ions (SO42-, NO3-, Cl-, Na+, NH4+, K+, Mg2+, Ca2+) with major contributions from SO42- (13%), NO3- (6%), NH4+ (6%) and Ca2+ (3%). Among the inorganic ions, SO42- exhibited the highest individual ion concentration at both sites with an average concentration of 1.5×1.2 ?g m-3 at West Site and 1.5×1.3 ?g m-3 at East Site. The average NO3- concentrations for this period were 0.5×0.4 ?g m-3 and 0.7×0.5 ?g m-3 at West and East Sites, respectively. Comparison of aerosol composition data from the two sites indicated that concentrations of SO42-, NO3-, NH4+ and organic carbon were not statistically different at the 95% confidence interval, indicating that these species were primarily influenced by regional atmospheric processes. Meanwhile, Ca2+ and elemental carbon concentrations were statistically different across the two study sites, indicating the influence of local PM sources. Unlike other ions, Ca2+ concentrations were significantly elevated at both sites in October, during the agricultural harvest, showing that re-suspended soil dust is a temporally-variable source of fine particles that peaks during the agricultural harvest season. Several episodes of elevated PM2.5 occurred in late August to early October, with elevated levels of SO42-, NH4+, and organic carbon; these episodes occurred during periods of high temperature, dry atmospheric conditions, and southerly air masses that contributed to high secondary aerosol concentrations. NO3- concentrations increased from August to November, consistent with enhanced formation of NH4NO3 under colder temperatures. With the majority of PM2.5 attributed to secondary sources, we conclude that significant reductions in PM2.5 concentrations in Iowa City will require addressing secondary aerosol sources on a regional scale.

Jayarathne, T. S.; Stone, E.

2013-12-01

109

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

NASA Astrophysics Data System (ADS)

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46'S, 64°05'W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium, sulfate, magnesium, calcium, potassium, fluoride, ammonium, and nitrate, excluding hydrogen and hydroxide. The pH of these samples ranged between 4.0-6.2. The relatively low nitrate and relatively high sulfate concentrations found in our samples are consistent with the results of other studies for this region of Antarctica. The ions and pH do not appear to favor a particular wind direction during this period. The total deposition of sulfate and flouride via snowfall between 10 January and 10 February is conservatively estimated to be 4.78 and 1.3 kg km -2, respectively.

DeFelice, T. P.

110

Chemical Composition of Nebulosities in the Magellanic Clouds  

PubMed Central

From photoelectric spectrophotometric data secured at Cerro Tololo Interamerican Observatory we have attempted to derive electron densities and temperatures, ionic concentrations, and chemical abundances of He, C, N, O, Ne, S, and Ar in nebulosities in the Magellanic Clouds. Although 10 distinct nebulosities were observed in the Small Cloud and 20 such objects in the Large Cloud, the most detailed observations were secured only for the brighter objects. Results for 30 Doradus are in harmony with those published previously and recent work by Peimbert and Torres-Peimbert. Nitrogen and heavier elements appear to be less abundant in the Small Cloud than in the Large Cloud, in accordance with the conclusions of Dufour. A comparison with the Orion nebula suggests He, N, Ne, O, and S may all be less abundant in the Megellanic Clouds, although adequate evaluations will require construction of detailed models. For example, if we postulate that the [NII], [OII], and [SII] radiations originate primarily in regions with electron temperatures near 8000°K, while the [OIII], [NeIII], [ArIII], and H radiations are produced primarily in regions with T? = 10,000° K, the derived chemical abundances in the clouds are enhanced. PMID:16592199

Aller, L. H.; Czyzak, S. J.; Keyes, C. D.; Boeshaar, G.

1974-01-01

111

Chemical Communication  

NSDL National Science Digital Library

A concise lesson about chemical communication in insects covering both semio and info chemicals. The site includes a short video of grape root borer moths using sex pheromone. Further links on the take the user to visual and auditory communication.

0000-00-00

112

Calculations of the Chemical Composition of the Sacramento Urban Plume  

NASA Astrophysics Data System (ADS)

Recent measurements within the Sacramento urban plume have provided a detailed benchmark for testing our understanding of tropospheric chemistry. Available measurements include a wide suite of VOC and BVOC, NOy,i, O3, and CO at the source and at a receptor site five hours downwind. Further, the meteorology in the region is extremely regular making it possible to evaluate effects of temperature or day-of-week patterns with a single season of measurements. Here we use a Lagrangian model representing transport from Granite Bay, a suburb at the eastern edge of Sacramento, to the University of California Blodgett Forest Research Station (UC- BFRS). The model represents chemistry based on MCM v3.1 along with mixing and dilution. The model is initiated with concentrations of NOx, peroxynitrates, alkyl and multifunctional nitrates, HNO3, VOCs and O3 based on measurements at the edge of the Sacramento suburban sprawl east of the city. Biogenic VOC emissions throughout the transect are included. The outputs of the model are compared with ozone measurements at Cool three hours downwind, and detailed measurements of VOC, the speciation of the nitrogen oxides and O3 at UC-BFRS, 5 hours downwind of the Sacramento suburbs in the center of the Mountain counties air basin. The comparisons indicate 1) O3 at UC-BFRS and Cool is largely driven by the combination of rural biogenic emissions and urban NOx emissions, 2) that OH is underestimated by standard chemical models, 3) that partitioning of NOy is dominated by peroxy and other multifunctional nitrates that are not represented in standard chemical models and which have a strong impact on how much NO2 is available for ozone production. We also investigate model representation of temperature and weekend/weekday effects.

Perez, I. M.; Cohen, R. C.

2007-12-01

113

The chemical composition of red giants in 47 Tucanae. I. Fundamental parameters and chemical abundance patterns  

NASA Astrophysics Data System (ADS)

Context. The study of chemical abundance patterns in globular clusters is key importance to constraining the different candidates for intracluster pollution of light elements. Aims: We aim at deriving accurate abundances for a wide range of elements in the globular cluster 47 Tucanae (NGC 104) to add new constraints to the pollution scenarios for this particular cluster, expanding the range of previously derived element abundances. Methods: Using tailored 1D local thermodynamic equilibrium (LTE) atmospheric models, together with a combination of equivalent width measurements, LTE, and NLTE synthesis, we derive stellar parameters and element abundances from high-resolution, high signal-to-noise spectra of 13 red giant stars near the tip of the RGB. Results: We derive abundances of a total 27 elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ru, Ba, La, Ce, Pr, Nd, Eu, Dy). Departures from LTE were taken into account for Na, Al, and Ba. We find a mean [Fe/H] = -0.78 ± 0.07 and [ ?/ Fe ] = 0.34 ± 0.03 in good agreement with previous studies. The remaining elements show good agreement with the literature, but including NLTE for Al has a significant impact on the behavior of this key element. Conclusions: We confirm the presence of an Na-O anti-correlation in 47 Tucanae found by several other works. Our NLTE analysis of Al shifts the [Al/Fe] to lower values, indicating that this may be overestimated in earlier works. No evidence of an intrinsic variation is found in any of the remaining elements. Based on observations made with the ESO Very Large Telescope at Paranal Observatory, Chile (Programmes 084.B-0810 and 086.B-0237).Full Tables 2, 5, and 9 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/572/A108Appendix A is available in electronic form at http://www.aanda.org

Thygesen, A. O.; Sbordone, L.; Andrievsky, S.; Korotin, S.; Yong, D.; Zaggia, S.; Ludwig, H.-G.; Collet, R.; Asplund, M.; Ventura, P.; D'Antona, F.; Meléndez, J.; D'Ercole, A.

2014-12-01

114

Chemical engineer  

NSDL National Science Digital Library

What do chemical engineers actually do? This is the introductory page for a set of materials about chemical engineering as a career. Here the job of a chemical engineer is defined and described. Chemical engineers often work with industrial manufacturing processes that involve a mix of chemistry and engineering. In the rest of the resource, students can examine a specialized job title associated with chemical engineering: process engineer. Students can view a five-minute video clip of the process engineer as he works in a fertilizer plant making ammonia and urea. Students follow the engineer around the plant as he checks pressure in chemical lines. Students get a glimpse of the inside of a furnace during the chemical-making process. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2002-01-01

115

Variations in Chemical Compositions of Rosa damascena Mill. and Rosa canina L. Fruits  

Microsoft Academic Search

Kazaz S., Baydar H., Erbas S. (2009): Variations in chemical compositions of Rosa damascena Mill. and Rosa canina L. frui ts . Czech J. Food Sci., 27: 178-184. In this study, fruits, fruit flesh and seeds of damask rose ( Rosa damascena Mill.) and rose hip ( Rosa canina L.) were assayed for the composition of fatty acids, ascorbic acid,

Soner Kazaz; Hasan BaydaR

116

ENERGY SPECTRUM AND CHEMICAL COMPOSITION OF ULTRAHIGH ENERGY COSMIC RAYS FROM SEMI-RELATIVISTIC HYPERNOVAE  

SciTech Connect

It has been suggested that hypernova remnants, with a substantial amount of energy in semi-relativistic ejecta, can accelerate intermediate mass or heavy nuclei to ultrahigh energies and provide a sufficient amount of energy in cosmic rays to account for the observed flux. We here calculate the expected energy spectrum and chemical composition of ultrahigh energy cosmic rays from such semi-relativistic hypernovae. With a chemical composition equal to that of the hypernova ejecta and a flat or hard spectrum for cosmic rays at the sources, the spectrum and composition of the propagated cosmic rays observed at the Earth can be compatible with the measurements by the Pierre Auger Observatory.

Liu Ruoyu; Wang Xiangyu [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

2012-02-10

117

Chemical composition of atmospheric aerosols between Moscow and Vladivostok  

NASA Astrophysics Data System (ADS)

The TROICA-9 expedition (Trans-Siberian Observations Into the Chemistry of the Atmosphere) was carried out at the Trans-Siberian railway between Moscow and Vladivostok in October 2005. Measurements of aerosol physical and chemical properties were made from an observatory carriage connected to a passenger train. Black carbon (BC) concentrations in fine particles (PM2.5, aerodynamic diameter <2.5 ?m) were measured with an aethalometer using a five-minute time resolution. Concentrations of inorganic ions and some organic compounds (Cl-, NO3-, SO42-, Na+, NH4+, K+, Ca2+, Mg2+, oxalate and methane sulphonate) were measured continuously by using an on-line system with a 15-min time resolution. In addition, particle volume size distributions were determined for particles in the diameter range 3-850 nm using a 10-min. time resolution. The continuous measurements were completed with 24-h. PM2.5 filter samples which were stored in a refrigerator and later analyzed in chemical laboratory. The analyses included mass concentrations of PM2.5, ions, monosaccharide anhydrides (levoglucosan, galactosan and mannosan) and trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, V and Zn). The mass concentrations of PM2.5 varied in the range of 4.3-34.8 ?g m-3 with an average of 21.6 ?g m-3. Fine particle mass consisted mainly of BC (average 27.6%), SO42- (13.0%), NH4+ (4.1%), and NO3- (1.4%). One of the major constituents was obviously also organic carbon which was not determined. The contribution of BC was high compared with other studies made in Europe and Asia. High concentrations of ions, BC and particle volume were observed between Moscow and roughly 4000 km east of it, as well as close to Vladivostok, primarily due to local anthropogenic sources. In the natural background area between 4000 and 7200 km distance from Moscow, observed concentrations were low, even though there were local particle sources, such as forest fires, that increased occasionally concentrations. The measurements indicated that during forest fire episodes, most of the aerosol mass consisted of organic particulate matter. Concentrations of biomass burning tracers levoglucosan, oxalate and potassium were elevated close to the forest fire areas observed by the MODIS satellite. The polluted air masses from Asia seem to have significant influences on the concentration levels of fine particles over south-eastern Russia.

Kuokka, S.; Teinilä, K.; Saarnio, K.; Aurela, M.; Sillanpää, M.; Hillamo, R.; Kerminen, V.-M.; Vartiainen, E.; Kulmala, M.; Skorokhod, A. I.; Elansky, N. F.; Belikov, I. B.

2007-05-01

118

The Effect of Chemical Functionalization on Mechanical Properties of Nanotube/Polymer Composites  

NASA Technical Reports Server (NTRS)

The effects of the chemical functionalization of a carbon nanotube embedded in a nanotube/polyethylene composite on the bulk elastic properties are presented. Constitutive equations are established for both functionalized and non-functionalized nanotube composites systems by using an equivalent-continuum modeling technique. The elastic properties of both composites systems are predicted for various nanotube lengths, volume fractions, and orientations. The results indicate that for the specific composite material considered in this study, most of the elastic stiffness constants of the functionalized composite are either less than or equal to those of the non-functionalized composite.

Odegard, G. M.; Frankland, S. J. V.; Gates, T. S.

2003-01-01

119

Chemical composition and biological activities of Gerbera anandria.  

PubMed

Gerbera anandria (Compositae) was extracted with 75% ethanol and the residue was fractionated using light petroleum, chloroform and ethyl acetate. The constituents of the extracts were separated by column chromatography employing solvents of different polarity. Column chromatography of the light petroleum fraction resulted in the isolation of methyl hexadecanoate, while the chloroform fraction afforded xanthotoxin, 2-hydroxy-6-methylbenzoic acid, 7-hydroxy-1(3H)-isobenzofuranone, a mixture of ?-sitosterol and stigmasterol, and 8-methoxysmyrindiol and the ethyl acetate fraction gave gerberinside, apigenin-7-O-?-d-glucopyranoside and quercetin. A new coumarin, 8-methoxysmyrindiol, was found. The chemical structures of the isolated compounds were established by MS and NMR (HSQC, HMBC). Free radical scavenging and cytotoxic activities of crude extracts and 8-methoxysmyrindiol were further investigated. The ethyl acetate phase exerted the strongest DPPH free radical scavenging activity in comparison to the other fractions. The coumarin 8-methoxysmyrindiol demonstrated cytotoxicity against multiple human cancer cell lines, with the highest potency in HepG2 cells. PMID:24699147

He, Fa; Wang, Miao; Gao, Minghuan; Zhao, Min; Bai, Yuhua; Zhao, Chunjie

2014-01-01

120

Fine particulate chemical composition and light extinction at Meadview, AZ  

SciTech Connect

The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr daynight samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was {+-} 0.6 {mu}g/m{sup 3} organic material, {+-} 0.3 {mu}g/m{sup 3} ammonium sulfate, and {+-} 0.07 {mu}g/m{sup 3} ammonium nitrate. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides sources in the region indicate that the major anthropogenic contributors to light extinction were from the Los Angeles, CA, and Las Vegas, NV, urban areas. Mohave Power Project associated secondary sulfate was a negligible contributor to light extinction. 49 refs., 12 figs., 7 tabs.

Delbert J. Eatough; Wenxuan Cui; Jeffery Hull; Robert J. Farber [Brigham Young University, Provo, UT (United States). Department of Chemistry and Biochemistry

2006-12-15

121

Z .Chemical Geology 145 1998 325394 The chemical composition of subducting sediment and its  

E-print Network

­mantle recycling. Models of continental growth, continental composition, convergent margin magmatism and mantle to assess the importance of sediments to arc volcanism and crust­mantle recycling, and to re Science B.V. All rights reserved. Z .PII S0009-2541 97 00150-2 #12;( )T. Plank, C.H. Langmuirr

Langmuir, Charles H.

122

Chemical burns  

PubMed Central

Objectives To report a burn unit’s experience with chemical burns and to discuss the fundamental principles in managing chemical burns. Design A chart review. Setting A burn centre at a major university-affiliated hospital. Patients Twenty-four patients with chemical burns, representing 2.6% of all burn admissions over an 8-year period at the Ross Tilley Regional Adult Burn Centre. Seventy-five percent of the burn injuries were work-related accidents. Chemicals involved included hydrofluoric acid, sulfuric acid, black liquor, various lyes, potassium permanganate and phenol. Results Fourteen patients required excision and skin grafting. Complications were frequent and included ocular chemical contacts, wound infections, tendon exposures, toe amputation and systemic reactions from absorption of chemical. One patient died from a chemical scald burn to 98% of the body surface area. Conclusions The key principles in the management of chemical burns include removal of the chemical, copious irrigation, limited use of antidotes, correct estimation of the extent of injury, identification of systemic toxicity, treatment of ocular contacts and management of chemical inhalation injury. Individualized treatment is emphasized. PMID:8640619

Cartotto, Robert C.; Peters, Walter J.; Neligan, Peter C.; Douglas, Leith G.; Beeston, Jeff

1996-01-01

123

Chemical composition and 13C NMR spectroscopic characterisation of ulvans from Ulva (Ulvales, Chlorophyta)  

Microsoft Academic Search

The chemical composition and structures of several ulvan extracts isolated from various Ulva species were studied. They were\\u000a all composed mainly of rhamnose, glucuronic acid, xylose, glucose and sulphate with smaller amounts of iduronic acid and traces\\u000a of galactose. Proteins were also present, most likely as contaminants. Precise quantification of the uronic acid content by\\u000a chemical-enzymatic hydrolysis coupled to HPAEC-PAD

Marc Lahaye; Enrique Alvarez-Cabal Cimadevilla; Ralph Kuhlenkamp; Bernard Quemener; Vincent Lognoné; Patrick Dion

1999-01-01

124

Composition, microstructure, and thermal stability of silicon carbide chemical vapor deposited at low temperatures  

Microsoft Academic Search

In this paper, the authors have examined the chemical composition, microstructure, and thermal stability of silicon carbide chemical vapor deposited at relatively low temperatures ranging from 1000 to 1300°C. Within the present deposition-temperature range, pure silicon carbide was obtained that was composed mainly of cubic-type beta silicon carbide with a small amount of hexagonal-type silicon carbide. Neither free silicon nor

Yongdong Xu; Laifei Cheng; Litong Zhang

2000-01-01

125

Photochemical evolution of submicron aerosol chemical composition in the Tokyo megacity region in summer  

Microsoft Academic Search

We investigate the chemical transformation of submicron aerosol in the Tokyo megacity region in summer. An Aerodyne quadrupole aerosol mass spectrometer (AMS) was deployed both at an urban site in Tokyo (35°39?N, 139°40?E) and a suburban site (downwind site) in Saitama (36°05?N, 139°33?E) in the summer of 2004. The temporal evolution of size-resolved chemical compositions of submicron (PM1) aerosols during

T. Miyakawa; N. Takegawa; Y. Kondo

2008-01-01

126

Chemical engineers design, control and optimize large-scale chemical,  

E-print Network

advanced composites used in automotive and space-related industries to materials used in the biomedical Chemical Reactor Analysis (3, Fa) Basic concepts of chemical kinetics and chemical reactor design

Rohs, Remo

127

Chemical engineers design, control and optimize large-scale chemical,  

E-print Network

advanced composites used in automotive and space-related industries to materials used in the biomedical) CHE 442 Chemical Reactor Analysis (3, Fa) Basic concepts of chemical kinetics and chemical reactor

Rohs, Remo

128

Chemical microsensors  

DOEpatents

An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

Li, DeQuan (Los Alamos, NM); Swanson, Basil I. (Los Alamos, NM)

1995-01-01

129

Tunable shrink induced graphene composites for chemical sensors and microfluidics  

Microsoft Academic Search

The shrink induced graphene composites based on layer-by-layer (LbL) self-assembly technique reported in this paper demonstrates controllably tunable features different from the conventional graphene composites. By self-assembly of graphene nanoplatelets on a polyolefin (PO) shrink film substrate, the surface morphologies of the graphene composites were capable of turning through controlling the shrink temperature. SEM and AFM were used to analyze

B. Zhang; T. Cui

2012-01-01

130

[Chemical composition of earthworm (Eisenia fetida and Lumbricus rubellus) silages].  

PubMed

Earthworms (Eisenia fetida and Lumbricus rubellus) were ensiled with ground sorghum and molasses in the following proportions: 1) 60% earthworms, 40% sorghum; 2) 60% earthworms, 40% sorghum, adjusting pH to 4.0 with HCl; 3) 60% earthworms, 20% sorghum, 20% molasses; 4) 60% earthworms, 20% sorghum, 20% molasses, adjusting pH to 4.0 with HCl. These mixtures were allowed to ferment for 15 days at 18 degrees C. pH, proximate chemical analyses, digestible protein, true protein, ammonia nitrogen, acetic, propionic and butyric acid, lactic acid and gross energy were analyzed in the ensiled mixtures. Data were analyzed by ANOVA and orthogonal contrasts. No differences (P > 0.0001) were found in the percentage of moisture, ether extract, crude fiber and crude protein (52.22, 2.96, 1.15, 22.00, 51.76, 3.48, 1.28, 20.17; 53.89, 3.23, 0.95, 20.63; 54.87, 2.99, 1.03, 21.14, for treatments 1, 2, 3 and 4, respectively). Neither there was any difference (P > 0.0001) for true protein and gross energy (7.57, 4.37; 6.92, 4.41; 5.45, 4.37; 6.38, 4.30, for treatments 1, 2, 3 and 4, respectively). Ash content (P < 0.0001) and nitrogen free extract (p < 0.02) were different between treatments with sorghum and treatments with sorghum and molasses (3.80, 70.09; 3.60, 71.47; 6.08, 69.11; 6.63, 68.21, for treatments 1, 2, 3 and 4, respectively). Digestible protein was also different (P < 0.01) for treatment 1 (96.78) than 2 (94.34). pH values were lower (P < 0.03) for treatment 2 (3.80) and 4 (3.76), where HCl was added than for 1 (4.06) and 3 (4.16). Ammonia nitrogen values were very low for all treatments. Lactic:acetic acid ratio was large for all treatments (7.55, 14.83, 8.30, 7.63 for treatments 1, 2, 3 and 4, respectively). It is concluded that it is possible to preserve the earthworms E. fetida and L. rubellus by ensiling, adding a source of carbohydrates, such as sorghum or molasses. Not being necessary the addition of acids to have an adequate fermentation. PMID:9429616

Ortega Cerrilla, M E; Reyes Ortigoza, A L; Mendoza Martínez, G

1996-12-01

131

Chemical composition of rainwater at EMEP station in Ankara, Turkey  

NASA Astrophysics Data System (ADS)

The chemical characteristics of rainfall and its seasonal variation at the EMEP (The Cooperative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe) station located in Cubuk, Ankara were studied for the period between September 1994 and December 1996. The station is located in a rural area about 50 km north of Ankara and is considered as a background station for air pollution. The rainwater samples collected were analyzed for pH, major ions concentrations and conductivity. Seasonal variations for some major ions are pronounced. Generally, maximum concentrations appeared in winter or autumn, and minimum concentrations in spring or summer seasons. The average pH of rainwater samples is around 6.3 due to neutralization. Only about 4% of the rain samples had a pH below 5.0 and about 15% of the total rainwater samples had a pH below 5.6. This reflects strong inputs of alkaline species to rainwater samples in this location. The average pH of the samples higher than 5.6 observed in rural area of Ankara is due to a high loading of calcium ions in the form of CaCO 3 because of the alkaline nature of the soil. There is a strong relationship between pHs and other ions in summer. However, in winter, a weak relationship is found between SO 42-, NO 3-, Na + and Mg 2+. On the other hand, relationships between the conductivity and SO 42- concentration are stronger in summer than in winter. The low concentrations of H + found in rainwater samples from Cubuk suggests that an important portion of H 2SO 4 and HNO 3 have been neutralized by alkaline particles in the atmosphere. Weak correlations are found between the hydrogen ions and SO 42- or NO 3- ions for all seasons because of neutralization of these ions with alkaline particles. The dust-rich local and surrounding limestone environment might have caused the high concentration of Ca 2+ in Cubuk area. The relatively high concentration of NH 4+ observed at Cubuk is suspected to be due to surrounding agricultural activity. This agricultural activity has been found to be effective not only in spring, but also in autumn and winter to cause neutralization of the rainwater.

Topçu, Sema; Incecik, Selahattin; Atimtay, Aysel T.

132

Genetic significance of the chemical composition of tektites: A review  

Microsoft Academic Search

Evidence from internal compositional variations and ratios, selective vaporisation and impact glass analogies, bearing on the relationship of the present composition to that of the parent material indicates that concentration changes during melting have been minor, thus enabling the parent material to be identified. Terrestrial igneous rocks are not suitable source material, but terrestrial sandstones (greywackes-subgreywackes-arkoses) show strong similarities in

S. R. Taylor; Maureen Kaye

1969-01-01

133

Model nebulae and determination of the chemical composition of the Magellanic Clouds  

PubMed Central

An analysis of previously presented photoelectric spectrophotometry of HII regions (emission-line diffuse nebulae) in the two Magellanic Clouds is carried out with the aid of theoretical nebular models, which are used primarily as interpolation devices. Some advantages and limitations of such theoretical models are discussed. A comparison of the finally obtained chemical compositions with those found by other observers shows generally a good agreement, suggesting that it is possible to obtain reliable chemical compositions from low excitation gaseous nebulae in our own galaxy as well as in distant stellar systems. PMID:16592633

Aller, L. H.; Keyes, C. D.; Czyzak, S. J.

1979-01-01

134

Model nebulae and determination of the chemical composition of the Magellanic Clouds.  

PubMed

An analysis of previously presented photoelectric spectrophotometry of HII regions (emission-line diffuse nebulae) in the two Magellanic Clouds is carried out with the aid of theoretical nebular models, which are used primarily as interpolation devices. Some advantages and limitations of such theoretical models are discussed. A comparison of the finally obtained chemical compositions with those found by other observers shows generally a good agreement, suggesting that it is possible to obtain reliable chemical compositions from low excitation gaseous nebulae in our own galaxy as well as in distant stellar systems. PMID:16592633

Aller, L H; Keyes, C D; Czyzak, S J

1979-04-01

135

CHEMICAL ENGINEERING AND MANUFACTURING CHEMICAL ENGINEERING  

E-print Network

CHEMICAL ENGINEERING AND MANUFACTURING CHEMICAL ENGINEERING Objective Chemical Engineers of chemicals. This lesson introduces students to one component of chemical engineering: food processing, and a chemical engineer 2. How chemical engineers are involved in food production 3. That chemical engineers need

Provancher, William

136

Level and Chemical Composition of Cryoglobulins in Schizophrenia  

NASA Astrophysics Data System (ADS)

The blood samples of 40 schizophrenic patients were tested for the presence of cryoglobulins (Cgs) and composition of Cgs was examined. The elevated levels of type III Cgs, containing complement components, were detected in all study subjects.

Khoyetsyan, Aren; Boyajyan, Anna; Melkumova, Maya

137

Chemical Name  

Cancer.gov

Attachment III Chemical Quick Reference Chart for Minors Chemical Name Select Carcinogen Reproductive Toxin LD50 < 50 mg/kg (oral rat) LD50 < 200 mg/kg for 24 hours or less (dermal rabbit) LC50 < 200 ppm or 2 mg/L for one hour (inhalation rat)

138

Chemical sensors  

DOEpatents

Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising (a) a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, operatively coupled to (b) a transducer capable of directly converting said expansion or contraction to a measurable electrical response.

Lowell, Jr., James R. (Bend, OR); Edlund, David J. (Bend, OR); Friesen, Dwayne T. (Bend, OR); Rayfield, George W. (Bend, OR)

1991-01-01

139

Chemical sensors  

DOEpatents

Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

1991-07-02

140

Chemical Reactions  

NSDL National Science Digital Library

We don't often stop to think about it, but underlying many of our everyday activities are chemical reactions. From the cooking of an egg to the growth of a child, chemical reactions make things happen. Although many of the reactions that support our lives

National Science Teachers Association (NSTA)

2009-05-01

141

Chemical preconcentrator  

DOEpatents

A chemical preconcentrator is disclosed with applications to chemical sensing and analysis. The preconcentrator can be formed by depositing a resistive heating element (e.g. platinum) over a membrane (e.g. silicon nitride) suspended above a substrate. A coating of a sorptive material (e.g. a microporous hydrophobic sol-gel coating or a polymer coating) is formed on the suspended membrane proximate to the heating element to selective sorb one or more chemical species of interest over a time period, thereby concentrating the chemical species in the sorptive material. Upon heating the sorptive material with the resistive heating element, the sorbed chemical species are released for detection and analysis in a relatively high concentration and over a relatively short time period. The sorptive material can be made to selectively sorb particular chemical species of interest while not substantially sorbing other chemical species not of interest. The present invention has applications for use in forming high-sensitivity, rapid-response miniaturized chemical analysis systems (e.g. a "chem lab on a chip").

Manginell, Ronald P. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM)

2001-01-01

142

Chemical and mineral composition of dust and its effect on the dielectric constant  

SciTech Connect

Chemical analysis is carried out for dust sample collected from central Sudan and the dust chemical constituents are obtained. The mineral composition of dust are identified by the X-ray diffraction techniques. The mineral quantities are obtained by a technique developed based on the chemical analytical methods. Analyses show that Quartz is the dominant mineral while the SiO{sub 2} is the dominant oxide. A simple model is derived for the dust chemical constituents. This model is used with models for predicting the mixture dielectric constant to estimate the dust dielectric constant; the results of which are seen to be in a good agreement with the measured values. The effects of the different constituents on the dust dielectric constant are studied and results are given.

Sharif, S. [Univ. of Khartoum (Sudan). Electrical Engineering Dept.] [Univ. of Khartoum (Sudan). Electrical Engineering Dept.

1995-03-01

143

Chemical Composition and Manufacturing Technology of a Collection of Various Types of Islamic Glazes Excavated from Jordan  

Microsoft Academic Search

A collection of Islamic glazed pottery shards that were excavated from the archaeological site of Dohaleh\\/Northern Jordan were chemically analysed. The glazes belong to three different decorative styles. The chemical analysis of the glazes was carried out using energy dispersive x-ray fluorescence. The chemical analysis results enable the classification of the glazes into the three distinct compositional groups with reference

Ziad Al-Saad

2002-01-01

144

MINEQL-EIR. Chemical Equilibrium Composition of Aqueous Systems  

SciTech Connect

MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C.

Westall, J.C.; Zachary, J.L.; Morel, F.M.M [Massachusetts Institute of Technology, Cambridge (United States); Schweingruber, M. [Eidgenoessisches Institut for Reaktorforschung, Wuerenlingen (Switzerland)

1986-11-21

145

Generation rates and chemical compositions of waste streams in a typical crewed space habitat  

NASA Technical Reports Server (NTRS)

A judicious compilation of generation rates and chemical compositions of potential waste feed streams in a typical crewed space habitat was made in connection with the waste-management aspect of NASA's Physical/Chemical Closed-Loop Life Support Program. Waste composition definitions are needed for the design of waste-processing technologies involved in closing major life support functions in future long-duration human space missions. Tables of data for the constituents and chemical formulas of the following waste streams are presented and discussed: human urine, feces, hygiene (laundry and shower) water, cleansing agents, trash, humidity condensate, dried sweat, and trace contaminants. Tables of data on dust generation and pH values of the different waste streams are also presented and discussed.

Wydeven, Theodore; Golub, Morton A.

1990-01-01

146

Chemical Composition of Soils of Northwest and West Central Texas.  

E-print Network

- , Washington, D. C. The Texas Agricultural Experiment Station has hies of the soil surveys for distribution. Northwest Texas Survey includes 22 counties in three tiers just south Panhandle region, comprising an area of 19,404 square miles. The es included... [ICAL COMPOSITION OF SOILS OF NORTHWEST AND WEST CENTRAL TEXAS fiGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON, President STATION STAFFt ~dministration : Veterinary Science: A. B. Conner, M. S.. Director *M. Francis D. V. M Chief R. E...

Fraps, G. S. (George Stronach)

1932-01-01

147

The effect of sulfate sulfur on the yield and chemical composition of oats, vetch, and turnips  

E-print Network

for the degree af ~ OF SCIEN;E Angust, 1959 Eager Snbgeot s Agronosy THE EFFECT OF SULFATE SULFUR ON THE IIELD AND CHEMICAL COMPOSITION OF OATS, VETCH~ AND TURNIPS A Thesis By JACK RCOERS GIPSON . j, ' / g / ~ / g/ g/ g/ / &e 8/ ~ / Approved... suggestions. CONTENTS Introduction. Review of Literature, . Methods and Materials. Results. (1) Yield effects. (2) Chemioal composition. Discussion. ~ 3 . , 16 Sugary' Appendix Bibliography. 4 33 ~ 35 LIST OF TABLES Page Table 1 Pounds...

Gipson, Jack Rogers

1959-01-01

148

Screening of chemical composition, antimicrobial and antioxidant activities of Artemisia essential oils  

Microsoft Academic Search

The chemical composition of essential oils isolated from aerial parts of seven wild sages from Western Canada –Artemisia absinthium L., Artemisia biennis Willd., Artemisia cana Pursh, Artemisia dracunculus L., Artemisia frigida Willd., Artemisia longifolia Nutt. and Artemisia ludoviciana Nutt., was investigated by GC–MS. A total of 110 components were identified accounting for 71.0–98.8% of the oil composition. High contents of

Daíse Lopes-Lutz; Daniela S. Alviano; Celuta S. Alviano; Paul P. Kolodziejczyk

2008-01-01

149

Effect of Chemical Treatment of Kevlar Fibers on Mechanical Interfacial Properties of Composites  

Microsoft Academic Search

In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid–base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (KIC), and specific

Soo-Jin Park; Min-Kang Seo; Tae-Jun Ma; Douk-Rae Lee

2002-01-01

150

Microstructural and chemical effects of wet\\/dry cycling on pulp fiber–cement composites  

Microsoft Academic Search

The microstructural and chemical mechanisms responsible for pulp fiber–cement composite degradation during wet\\/dry cycling are being investigated through environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), and mechanical testing. Based on these results, a three-part progressive degradation mechanism for cast-in-place kraft pulp fiber–cement composites is proposed, which involves: (1) initial fiber–cement or fiber interlayer debonding, (2) reprecipitation of needle-like

B. J.. Mohr; J. J. Biernacki; K. E. Kurtis

2006-01-01

151

Chemical composition and net energy content of alpine pasture species during the grazing season  

Microsoft Academic Search

The aim of this study was to investigate changes over time in chemical composition, digestibility and net energy for lactation (NEl) contents of 12 species of alpine pastures during the vegetative season (i.e., Agrostis tenuis, Anthoxanthum alpinum, Carex sempervirens, Festuca rubra, Nardus stricta, Phleum alpinum, Poa alpina, Poa violacea, Alchemilla vulgaris, Leontodon hispidus, Potentilla aurea, Trifolium repens). Wild seeds were

S. Bovolenta; M. Spanghero; S. Dovier; D. Orlandi; F. Clementel

2008-01-01

152

Dependence of ceramics physical–mechanical properties on chemical and mineralogical composition  

Microsoft Academic Search

To determine the dependence of physical–mechanical properties of ceramics on chemical and mineralogical composition, the appropriate raw materials have been tested and five batches of ceramic specimens have been formed. The aforementioned specimens have been made of the following components: fusible clay, quartz sand, chamotte, sawdust and crushed window glass. The specimens differed by the amount of the components (differences

Jurgita Malaiskiene; Romualdas Maciulaitis; Asta Kicaite

2011-01-01

153

The Chemical Composition of Forage Grasses of the East Texas Timber Country.  

E-print Network

the principal species is white clover (Trifolium repens). CHEMICAL COMPOSITION OF FORAGE GRASSES 7 Collection of samples Forage samples were collected at various times between April and November in 1936 and 1937 from several counties well distributed... .......................... Digitaria ssnguinnlis ........................... .Asonopus fii~catus .......................... Medjclgn arabica ........................... .Medlclgo hispida .......................... .Trifolium repens...

Fraps, G. S. (George Stronach); Fudge, J. F. (Joseph Franklin)

1940-01-01

154

The effect of chemical composition and molecular weight of polysaccharide depressants on the flotation of talc  

Microsoft Academic Search

Polysaccharide reagents are frequently used in the mineral processing industry to improve the grade of the concentrate by depressing the naturally floatable gangue. A microflotation study showed that at an ionic strength of 10?3 M KNO3, the dosage, molecular weight, and chemical composition of polysaccharide depressants affect their depressing action on talc. Viscosity readings for four carboxymethylcellulose (CMC) reagents and

P. G. Shortridge; P. J. Harris; D. J. Bradshaw; L. K. Koopal

2000-01-01

155

A snapshot in the effect of time of day on herbage toughness and chemical composition  

Technology Transfer Automated Retrieval System (TEKTRAN)

Herbage chemical composition varies diurnally; however, it is not known if this variation affects herbage biomechanical properties. The objective of this study was to evaluate potential changes in herbage toughness and particle size reduction index (PSR) in relation to diurnal fluctuations of herbag...

156

Visualizing Chemical Compositions and Kinetics of Sol-Gel by Near-Infrared Multispectral Imaging  

E-print Network

Visualizing Chemical Compositions and Kinetics of Sol-Gel by Near-Infrared Multispectral Imaging, Milwaukee, Wisconsin 53201 Kinetics of sol-gel formation were studied using the recently developed near-infrared been studied extensively by many different spectroscopic techniques.4-15 Among them, the near-infrared

Reid, Scott A.

157

Prediction of chemical contaminants and food compositions by near infrared spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Prediction of Food Adulteration by Infrared Spectroscopy H. Zhuang Quality and Safety Assessment Research Unit, ARS-USDA, 950 College Station Road, Athens, GA 30605 Food adulteration, including both chemical contamination and composition alternation, has been one of major quality and/or safety c...

158

Chemical and mineral composition of ectomycorrhizosphere soils of subalpine fir (Abies  

E-print Network

Chemical and mineral composition of ectomycorrhizosphere soils of subalpine fir (Abies lasiocarpa- zosphere soils of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in the Ae horizon of a Luvisol. Can. J'ectomycorhi- zosphère sous sapin subalpin (Abies lasiocarpa (Hook.) Nutt.) dans l'horizon Ae d'un luvisol. Can. J. Soil

Massicotte, Hugues

159

The atmosphere of Canopus. II. Chemical composition. Determination of the mass, radius, luminosity, and age  

Microsoft Academic Search

The model proposed by Liubimkov and Boiarchuk (1982) is used in determining the abundances of 21 elements in the atmosphere of Canopus. The analysis is based on relatively weak lines so that the influence of inaccuracies in the microturbulence and in the damping will be reduced. The chemical composition of the atmosphere is found to be similar to that of

L. S. Lyubimkov; A. A. Boiarchuk

1982-01-01

160

Spectroscopic characterization of the chemical composition of the potent sweetener Vartamil  

NASA Astrophysics Data System (ADS)

The chemical composition of the potent sweetener Vartamil was characterized using spectral methods. It was demonstrated that Vartamil is a mixture of saccharose chloro derivatives, the main one of which is 4,1',6'-trichloro-4,1',6'-trideoxygalactosaccharose (Sucralose).

Kolosova, T. E.; Prokhodchenko, L. K.; Pilipenko, V. V.; Suboch, V. P.

2008-03-01

161

Comparison of chemical compositions of Ilex latifolia Thumb and Camellia sinensis L  

Microsoft Academic Search

Chemical composition of two beverage plant species, i.e. Ilex latifolia and Camellia sinensis were investigated. Fifteen and sixteen amino acids were detected in I. latifiolia and C. sinensis, respectively. Major amino acids were histidine, aspartic acid and glutamic acid in I. latifolia but theanine, glutamic acid and histidin in C. sinensis. Ascorbic acid and polyphenols in I. latifiolia were 0.46

Yuerong Liang; Weiyang Ma; Jianliang Lu; Ying Wu

2001-01-01

162

Effect of the Chemical Composition on The Pyroplastic Deformation of Sanitaryware Porcelain Body  

Microsoft Academic Search

Pyroplastic deformation is the bending of a ceramic specimen caused by gravity during heat treatment. It can be defined as the loss of shape of product during its firing. Pyroplastic deformation is related to properties of liquid phases formed during firing. Therefore, the effect of the chemical composition on the pyroplastic deformation of sanitaryware porcelain was investigated in this study.

Derya Yesim Tunçel; Mustafa Kerim Kara; Emel Özel

2011-01-01

163

Chemical composition of single aerosol particles at Idaho Hill: Positive ion measurements  

Microsoft Academic Search

The chemical compositions of single aerosol particles larger than 0.3 gm optical diameter were measured at Idaho Hill using a laser ionization mass spectrometer. The mass spectrometer can analyze either positive or negative ions; this paper covers the negative ion results. Sulfate, nitrate, organics, O-, and OH- were the most common peaks observed in the negative ion spectra. Other species

D. M. Murphy; D. S. Thomson

1997-01-01

164

Chemical composition of suspended sediments in World Rivers: New insights from a new database  

Microsoft Academic Search

The aim of this paper is to present a new database on the chemical composition of suspended matter in World Rivers, together with the associated elemental fluxes. There is a lack of any recent attempt in the literature to update the pioneering work of Martin and Meybeck [Martin, J.-M., Meybeck, M., 1979. Elemental mass balance of material carried by major

Jérôme Viers; Bernard Dupré; Jérôme Gaillardet

2009-01-01

165

Composite reactants of calcium chloride combined with functional carbon materials for chemical heat pumps  

Microsoft Academic Search

Enhancement of heat transfer in the reactor bed is one of the most important subjects for developing gas–solid chemical heat pumps. This study deals with composite reactants combining calcium chloride with expanded graphite (EG) and activated carbon fiber (ACF) to promote the reaction between calcium chloride and working fluid of methanol. We measured variations of effective thermal conductivity as well

Keiko Fujioka; Kensuke Hatanaka; Yushi Hirata

2008-01-01

166

Phoenix dactylifera L. spathe essential oil: Chemical composition and repellent activity against the yellow fever mosquito  

Technology Transfer Automated Retrieval System (TEKTRAN)

Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dacty...

167

Numerical simulation of the middle atmosphere chemical composition and temperature under changing solar conditions  

NASA Technical Reports Server (NTRS)

There are given results of the numerical experiments on modelling the influence of solar activity on chemical composition and temperature of the middle atmosphere. The consideration is made for peculiarities of solar activity impact under different values of antropogenic pollution of the atmosphere with chlorofluorocarbons and other stuff.

Zadorozhny, A. M.; Dyominov, I. G.; Tuchkov, G. A.

1989-01-01

168

Effect of forage conservation (hay or silage) on chemical composition of milk  

E-print Network

Note Effect of forage conservation (hay or silage) on chemical composition of milk JB Coulon P rations isonitrogenous. The cows fed grass silage yielded 0.7 kg/day (P milk than those fed hay, but their milk was significantly poorer in fat (-1.2 g/kg), proteins (-1.0 g/kg) and caseins

Boyer, Edmond

169

Chemical composition and functional properties of flour produced from two varieties of tigernut (Cyperus esculentus)  

Microsoft Academic Search

The chemical composition and functional properties of flour produced from two varieties (yellow and brown) of tigernut (Cyperus esculentus) seeds were studied. The seeds were obtained in dried form, sorted, wet cleaned, dried, milled and sieved to produce flour. The flours were tagged YTF and BTF for yellow and brown varieties, respectively. The protein contents of YTF and BTF were

170

CHEMICAL COMPOSITION AND NUTRITIVE VALUE OF BEE-COLLECTED AND BEE-STORED POLLEN  

E-print Network

CHEMICAL COMPOSITION AND NUTRITIVE VALUE OF BEE-COLLECTED AND BEE-STORED POLLEN Elton W. HERBERT, Jr. H. SHIMANUKI Bioenvironmental Bee Gaboratory, Plant Protection Institute, ARS, USDA Beltsville, MD 20705 SUMMARY When fresh pollen and bee-stored pollen extracted from brood combs of free

Paris-Sud XI, Université de

171

Creation and Analysis of the Chemical Composition Map of Eros and Its Cosmochemical Interpretation  

NASA Technical Reports Server (NTRS)

The data was analyzed and two papers were written and published in the refereed journal: Meteoritics and Planetary Science. These paper describes the results of the study of the surface chemical composition of the asteroid Eros by the NEAR X-ray Fluorescence Spectrometer.

Gorenstein, Paul; Morgan, Thomas (Technical Monitor)

2003-01-01

172

Linkages among the bioreactivity, chemical composition, and diagenetic state of marine dissolved organic matter  

Microsoft Academic Search

Bacterial growth and the chemical composition of dissolved organic matter (DOM) were followed during a 10- d decomposition experiment with fresh, algal-derived DOM from an Arctic ice floe. During the experiment ;30% of the dissolved organic carbon (DOC) was used by bacteria, indicating the highly reactive nature of this fresh DOM. Over half of the DOC consumption was accounted for

Rainer M. W. Amon; Hans-Peter Fitznar; Ronald Benner

2001-01-01

173

One-step synthesis and chemical characterization of Pt-C nanowire composites by plasma sputtering  

E-print Network

-Tek® carbon porous layer (CPL) is achieved in a magnetron sputtering reactor. Two rectangular targets, one. 10 nm) is explained in terms of a shadowing effect in magnetron sputtering process.[20] IncreasingOne-step synthesis and chemical characterization of Pt-C nanowire composites by plasma sputtering

Boyer, Edmond

174

Chemical composition and in vitro dry matter digestibility of various utilization forms of grain sorghum residues  

Microsoft Academic Search

The chemical composition and in vitro dry matter digestibility (IVDMD) of various utilization forms of grain sorghum residues were investigated. Two grain sorghum cultivars, SNK 3640 (bitter tasting) and Pioneer 8564 (sweet tasting), were used. Each taste type was grown on two soil types, viz. Rensburg and Bainsvlei. The results indicate that energy availability as reflected by the IVDMD, acid

L. D. Snyman; H. W. Joubert

1995-01-01

175

Galileo Probe Mass Spectrometer Measurements of the Chemical Composition of the Atmosphere of Jupiter  

Microsoft Academic Search

The chemical and isotopic composition of the Jovian atmosphere was measured by the Galileo Probe Mass Spectrometer (GPMS). This data was obtained on December 7, 1995 over a time period of approximately 1 hour during the probe descent in the 0.5 to 20 bar pressure region and transmitted to Earth over a period of several weeks. The sampling was either

H. B. Niemann; J. A. Haberman; D. N. Harpold; R. E. Hartle; W. T. Kasprzak; P. R. Mahaffy; S. K. Atreya; G. R. Carignan; T. M. Donahue; D. M. Hunten; T. C. Owen; N. W. Spencer

1996-01-01

176

Chemical composition measurements of the atmosphere of jupiter with the galileo probe mass spectrometer  

Microsoft Academic Search

The Galileo Probe entered the atmosphere of Jupiter on December 7, 1995. Measurements of the chemical and isotopic composition of the Jovian atmosphere were obtained by the mass spectrometer during the descent over the 0.5 to 21 bar pressure region over a time period of approximately 1 hour. The sampling was either of atmospheric gases directly introduced into the ion

H. B. Niemann; S. K. Atreya; G. R. Carignan; T. M. Donahue; J. A. Haberman; D. N. Harpold; R. E. Hartle; D. M. Hunten; W. T. Kasprzak; P. R. Mahaffy; T. C. Owen; N. W. Spencer

1998-01-01

177

Global chemical composition of ambient fine particulate matter for exposure assessment.  

PubMed

Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004-2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 ?g/m(3)), secondary inorganic aerosol (11.1 ± 5.0 ?g/m(3)), and mineral dust (11.1 ± 7.9 ?g/m(3)). Secondary inorganic PM2.5 concentrations exceeded 30 ?g/m(3) over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 ?g/m(3)) could be almost as large as from fossil fuel combustion sources (17 ?g/m(3)). These estimates offer information about global population exposure to the chemical components and sources of PM2.5. PMID:25343705

Philip, Sajeev; Martin, Randall V; van Donkelaar, Aaron; Lo, Jason Wai-Ho; Wang, Yuxuan; Chen, Dan; Zhang, Lin; Kasibhatla, Prasad S; Wang, Siwen; Zhang, Qiang; Lu, Zifeng; Streets, David G; Bittman, Shabtai; Macdonald, Douglas J

2014-11-18

178

Nutrient and Chemical Composition of 13 Wild Plant Foods of Niger  

Microsoft Academic Search

Human populations of the western Sahel depend upon a number of wild plant foods to satisfy a substantial part of their nutritional requirements, and this dependency increases during times of drought. However, the database of the nutrient and chemical compositions of these wild plant foods is incomplete and fragmentary. Herein we report the lipid, fatty acid, amino acid, total protein

Julia A. Cook; Dorothy J. VanderJagt; Andrzej Pastuszyn; Garba Mounkaila; Robert S. Glew; Mark Millson; Robert H. Glew

2000-01-01

179

Discerning the Chemical Composition and Mutagenic Effects of Soy Biodiesel PM  

EPA Science Inventory

Discerning the Chemical Composition and Mutagenic Effects of Soy Biodiesel PM David G. Nashab, Esra Mutluc, William T. Prestond, Michael D. Haysb, Sarah H. Warrenc, Charly Kingc, William P. Linakb, M. lan Gilmourc, and David M. DeMarinic aOak Ridge Institute for Science and Ed...

180

In-situ aircraft observations of the 2000 Mt. Hekla volcanic cloud: Composition and chemical  

E-print Network

In-situ aircraft observations of the 2000 Mt. Hekla volcanic cloud: Composition and chemical An instrumented NASA aircraft made comprehensive, in-situ measurements of trace gas concentrations and aerosol stratosphere. Thirty-five hours after the initial, sub- Plinian explosion on February 26, 2000, the aircraft

Lee, Shan-Hu

181

Chemical composition and antispasmodic effect of Casimiroa pringlei essential oil on rat uterus.  

PubMed

The Casimiroa pringlei essential oil was analyzed to determine its chemical composition. Its effect on rat uterine smooth muscle was studied and compared with verapamil. Pure commercial piperitone, eucalyptol, and alpha-terpineol, the major constituents of C. pringlei essential oil, were tested on the uterine tonic contraction induced by high-potassium depolarizing solution (KCl 60 mM). PMID:18538506

Ponce-Monter, Héctor; Campos, María G; Pérez, Salud; Pérez, Cuauhtémoc; Zavala, Miguel; Macías, Arturo; Oropeza, Martha; Cárdenas, Norma

2008-09-01

182

Atmospheric aerosols: A literature summary of their physical characteristics and chemical composition  

NASA Technical Reports Server (NTRS)

This report contains a summary of 199 recent references on the characterization of atmospheric aerosols with respect to their composition, sources, size distribution, and time changes, and with particular reference to the chemical elements measured by modern techniques, especially activation analysis.

Harris, F. S., Jr.

1976-01-01

183

Effects of chemical composition on the corrosion of dental alloys.  

PubMed

The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys. PMID:22666772

Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Rocha, Luís Augusto; de Mattos, Maria da Glória Chiarello

2012-01-01

184

Chemical composition of Silene morganae Freyn volatile oil.  

PubMed

The essential oil composition of flowering aerial parts of Iranian Silene morganae Freyn (Caryophyllaceae) was analysed for the first time using gas chromatography and gas chromatography-mass spectrometry. Thirty-one compounds consisting of 90.3% of the volatile oil were detected. The major constituents were benzaldehyde (11.6%), (Z)-3-hexenyl acetate (9.6%), (E)-?-ocimene (8.2%) and linalool (7.4%). Terpenoids (43.5%), particularly monoterpene hydrocarbons (24.2%), had the highest contribution in S. morganae Freyn flowering aerial parts oil. PMID:25422069

Azadi, Boshra; Sohrabi, Yousef

2014-11-25

185

AN ESTIMATE OF THE CHEMICAL COMPOSITION OF TITAN's LAKES  

SciTech Connect

Hundreds of radar-dark patches interpreted as lakes have been discovered in the north and south polar regions of Titan. We have estimated the composition of these lakes by using the direct abundance measurements from the Gas Chromatograph Mass Spectrometer aboard the Huygens probe and recent photochemical models based on the vertical temperature profile derived by the Huygens Atmospheric Structure Instrument. Thermodynamic equilibrium is assumed between the atmosphere and the lakes, which are also considered nonideal solutions. We find that the main constituents of the lakes are ethane (C{sub 2}H{sub 6}) (approx76%-79%), propane (C{sub 3}H{sub 8}) (approx7%-8%), methane (CH{sub 4}) (approx5%-10%), hydrogen cyanide (HCN) (approx2%-3%), butene (C{sub 4}H{sub 8}) (approx1%), butane (C{sub 4}H{sub 10}) (approx1%), and acetylene (C{sub 2}H{sub 2}) (approx1%). The calculated composition of lakes is then substantially different from what has been expected from models elaborated prior to the exploration of Titan by the Cassini-Huygens spacecraft.

Cordier, Daniel [Ecole Nationale Superieure de Chimie de Rennes, CNRS, UMR 6226, Avenue du General Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Mousis, Olivier; Lunine, Jonathan I.; Lavvas, Panayotis [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ (United States); Vuitton, Veronique, E-mail: daniel.cordier@ensc-rennes.f [Universite Joseph Fourier, Laboratoire de Planetologie de Grenoble, CNRS/INSU (France)

2009-12-20

186

[Submerged cultivation and chemical composition of Hericium erinaceus mycelium].  

PubMed

Submerged cultivation of Hericium erinaceus in various media was studied. The yield of the biomass was shown to depend mainly on the carbon source, whereas the content of water soluble polysaccharides depended mainly on the nitrogen source. The optimal medium composition provided the biomass yield of 21-23 g/l in 7 days. The biomass was characterized by the content of total protein, lipids and carbohydrates. In addition, the amino acid composition of the biomass was determined and shown to meet all the requirements of FAO/WHO concerning the amounts of essential amino acids (with exception of tryptophane). Oleinic and linoleic acids were identified as the main components of the fatty acids. Two water soluble polysaccharide fractions differing in solubility in aqueous ethanol were isolated and shown to contain rhamnose, fucose, xylose, glucose and galactose in different proportions. Vitamins B1, B2, B6, PP and E, ergosterol and coenzyme Q were also detected in the biomass of H. erinaceus. PMID:23350189

Avtonomova, A V; Bakanov, A V; Shuktueva, M I; Vinokurov, V A; Popova, O V; Usov, A I; Krasnopol'skaia, L M

2012-01-01

187

Vitrified metal finishing wastes I. Composition, density and chemical durability.  

PubMed

Durable phosphate glasses were formed by vitrifying waste filter cakes from two metal finishing operations. Some melts formed crystalline components during cooling. Compositional analysis of dried, heat treated and vitrified samples was made using energy-dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, inductively-coupled plasma spectroscopy and Leco induction furnace combustion analysis. Hydrolytic dissolution, measured by an adapted product consistency test, was reduced by up to 3 orders of magnitude upon heat treatment or vitrification, surpassing the performance of borosilicate glass in some cases. This was attributed to the high levels of iron and zinc in the wastes, which greatly improve the durability of phosphate glasses. One of the wastes arose from a metal phosphating process and was particularly suitable for vitrification due to its high P2O5 content and favourable melting behaviour. The other waste, which arose from a number of processes, was less suitable as it had a low P2O5 content and during heating it emitted harmful corrosive gases and underwent violent reactions. Substantial volume reductions were obtained by heat treatment and vitrification of both wastes. Compositions and performances of some vitrified wastes were comparable with those of glasses which are under consideration for the immobilisation of toxic and nuclear wastes. PMID:15752857

Bingham, P A; Hand, R J

2005-03-17

188

Chemical composition of Eastern Black Sea aerosol--preliminary results.  

PubMed

Trace element composition of atmospheric particles collected at a high altitude site on the Eastern Black Sea coast of Turkey was investigated to understand atmospheric transport of pollutants to this semi-closed basin. Aerosol samples were collected at a timber-storage area, which is operated by the General Directorate of Forestry. The site is situated at a rural area and is approximately 50 km to the Black Sea coast and 200 km to the Georgia border of Turkey. Coarse (PM2.5-10) and fine (PM2.5) aerosol samples were collected between 2011 and 2013 using a "stacked filter unit". Collected samples were shipped to the Middle East Technical University in Ankara, where Na, Mg, Al, Si, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Ba, Pb were measured by Energy dispersive x-ray fluorescence technique (EDXRF). Comparison of measured concentrations of elements with corresponding data generated at other parts of Turkey demonstrated that concentrations of pollution derived elements are higher at Eastern Black Sea than their corresponding concentrations measured at other parts of Turkey, which is attributed to frequent transport of pollutants from north wind sector. Positive matric factorization revealed four factors including three anthropogenic and a crustal factor. Southeastern parts of Turkey, Georgia and Black Sea coast of Ukraine were identified as source regions affecting composition of particles at our site, using trajectory statistics, namely "potential source contribution function" (PSCF). PMID:24373640

Balc?lar, Ilker; Zarars?z, Abdullah; Kalayc?, Yakup; Do?an, Güray; Tuncel, Gürdal

2014-08-01

189

Chemical synthesis of proteins.  

PubMed

Proteins have become accessible targets for chemical synthesis. The basic strategy is to use native chemical ligation, Staudinger ligation, or other orthogonal chemical reactions to couple synthetic peptides. The ligation reactions are compatible with a variety of solvents and proceed in solution or on a solid support. Chemical synthesis enables a level of control on protein composition that greatly exceeds that attainable with ribosome-mediated biosynthesis. Accordingly, the chemical synthesis of proteins is providing previously unattainable insight into the structure and function of proteins. PMID:15869385

Nilsson, Bradley L; Soellner, Matthew B; Raines, Ronald T

2005-01-01

190

Chemical Synthesis of Proteins  

PubMed Central

Proteins have become accessible targets for chemical synthesis. The basic strategy is to use native chemical ligation, Staudinger ligation, or other orthogonal chemical reactions to couple synthetic peptides. The ligation reactions are compatible with a variety of solvents and proceed in solution or on a solid support. Chemical synthesis enables a level of control on protein composition that greatly exceeds that attainable with ribosome-mediated biosynthesis. Accordingly, the chemical synthesis of proteins is providing previously unattainable insight into the structure and function of proteins. PMID:15869385

Nilsson, Bradley L.; Soellner, Matthew B.; Raines, Ronald T.

2010-01-01

191

Investigation of the chemical composition-antibacterial activity relationship of essential oils by chemometric methods.  

PubMed

The antibacterial effects of Thymus vulgaris (Lamiaceae), Lavandula angustifolia (Lamiaceae), and Calamintha nepeta (Lamiaceae) Savi subsp. nepeta var. subisodonda (Borb.) Hayek essential oils on five different bacteria were estimated. Laboratory control strain and clinical isolates from different pathogenic media were researched by broth microdilution method, with an emphasis on a chemical composition-antibacterial activity relationship. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalool acetate (38.23%) and ?-linalool (35.01%) were main compounds in lavender oil. C. nepeta essential oil was characterized by a high percentage of piperitone oxide (59.07%) and limonene (9.05%). Essential oils have been found to have antimicrobial activity against all tested microorganisms. Classification and comparison of essential oils on the basis of their chemical composition and antibacterial activity were made by utilization of appropriate chemometric methods. The chemical principal component analysis (PCA) and hierachical cluster analysis (HCA) separated essential oils into two groups and two sub-groups. Thyme essential oil forms separate chemical HCA group and exhibits highest antibacterial activity, similar to tetracycline. Essential oils of lavender and C. nepeta in the same chemical HCA group were classified in different groups, within antibacterial PCA and HCA analyses. Lavender oil exhibits higher antibacterial ability in comparison with C. nepeta essential oil, probably based on the concept of synergistic activity of essential oil components. PMID:22389175

Miladinovi?, Dragoljub L; Ili?, Budimir S; Mihajilov-Krstev, Tatjana M; Nikoli?, Nikola D; Miladinovi?, Ljiljana C; Cvetkovi?, Olga G

2012-05-01

192

The chemical composition of fogs and clouds in Southern California  

SciTech Connect

The major inorganic species in cloud and fog water samples were NH{sub 4}{sup +}, H{sup +}, NO{sub 3}{sup {minus}}, and SO{sub 4}{sup 2{minus}}. Concentrations in fog water samples were 1 - 10 {times} 10{sup {minus}3} M; pH values ranged from {approx equal} 2 to 6. Nitrate usually exceeded sulfate. Acidity depended on the availability of NH{sub 3} from agricultural operations. Stratus cloudwater had somewhat lower concentrations; pH values were in the range 3-4. The major factors accounting for variation in fog- or cloudwater composition were the preexisting aerosol and gas concentrations and variations in liquid water content. Deposition and entrainment or advection of different air masses were also important during extended cloud or fog episodes. The droplet size dependence of cloudwater composition was investigated on one occasion in an intercepted coastal stratus clouds. Concentrations of S(IV) and CH{sub 2}O in the range 100-1000 {mu}M were observed in fogwater from urban sites in Southern California. Lower concentrations were observed in stratus clouds. The high levels of S(IV) and CH{sub 2}O were attributed to the formation of hydroxymethanesulfonate (HMSA), the S(IV) adduct of CH{sub 2}O. Direct measurements of HMSA in fogwater samples from Bakersfield, CA were made by ion-pairing chromatography. Glyoxal and methyglyoxal were observed at concentrations comparable to CH{sub 2}O in fogwater samples from Riverside, CA and in stratus cloudwater samples from sites along the Santa Barbara Channel.

Munger, J.W.

1989-01-01

193

Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning  

NASA Technical Reports Server (NTRS)

Recent modeling of atmospheric chemical processes (Logan et al, 1978; Hameed et al, 1979) suggests that tropospheric ozone and methane might significantly increase in the future as the result of increasing anthropogenic emissions of CO, NO(x), and CH4 due to fossil fuel burning. Since O3 and CH4 are both greenhouse gases, increases in their concentrations could augment global warming due to larger future amounts of atmospheric CO2. To test the possible climatic impact of changes in tropospheric chemical composition, a zonal energy-balance climate model has been combined with a vertically averaged tropospheric chemical model. The latter model includes all relevant chemical reactions which affect species derived from H2O, O2, CH4, and NO(x). The climate model correspondingly incorporates changes in the infrared heating of the surface-troposphere system resulting from chemically induced changes in tropospheric ozone and methane. This coupled climate-chemical model indicates that global climate is sensitive to changes in emissions of CO, NO(x) and CH4, and that future increases in these emissions could augment global warming due to increasing atmospheric CO2.

Hameed, S.; Cess, R. D.; Hogan, J. S.

1980-01-01

194

Chemical lasers  

NASA Astrophysics Data System (ADS)

Fundamental properties of chemical lasers are presented and principal systems described in the nonclassified literature are reviewed. The fundamentals of the production of inversion in molecular gases by chemical processes are discussed. Iodine, HF, and DF lasers are described. The chemical reaction in the pulsed chemical HF and DF lasers is introduced by a transverse electrical discharge. In spite of the high dissociation energy and the electronegative properties which are unfavorable for a stable discharge regime, SF6 is used as fluorine source for safety reasons. The pulse energies reach 26 J in agreement with estimated values. The advantage of the present system is that is can also operate as CO2 laser in the TEA mode. The radiation of DF lasers is particularly interesting for military near-Earth applications because of its good transmission properties in the atmosphere.

Hugenschmidt, M.; Wey, J.

1985-05-01

195

Chemical Peeling  

MedlinePLUS

... the skin heals can cause unwanted side effects ranging from infection to scarring. If you have any ... Tanzi EL and Alster TS. “Skin Resurfacing: Ablative Lasers, Chemical Peels, and Dermabrasion.” In: Wolff K, Goldsmith ...

196

Chemical Emergency  

MedlinePLUS

... can be recycled, which is better for our environment. If you have questions about how to dispose of a chemical, call the facility or the environmental or recycling agency to learn the proper method of disposal. ...

197

Unnecessary Chemicals  

ERIC Educational Resources Information Center

Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

Johnson, Anita

1978-01-01

198

Chemical sensors  

DOEpatents

Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material. 12 figs.

Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

1992-06-09

199

Chemical sensors  

DOEpatents

Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material.

Lowell, Jr., James R. (Bend, OR); Edlund, David J. (Bend, OR); Friesen, Dwayne T. (Bend, OR); Rayfield, George W. (Eugene, OR)

1992-01-01

200

Chemical Composition of Rocks and Soils at Gale Crater, Mars  

NASA Astrophysics Data System (ADS)

Gale crater was selected as the landing site for the Mars Science Laboratory rover for its 5 km tall sedimentary mound, which includes phyllosilicate-containing layers near its base. Gale (5.4°S 137.8°E) is located near the north-south dichotomy and is one of the deepest craters in the region (lowest elevation is -4674 m). The lower part of the crater, near the landing ellipse, features an alluvial fan descending from the rim and overlying a region of high thermal inertia which appears to be layered. In addition to the fan, inverted channels indicate that water flowed in this region prior to some deflation. Nearer to the mound lies a dune field, and water-carved canyons descend from the mound. The Curiosity rover is equipped with several instruments with broad elemental composition capabilities to investigate along the traverse the expected variations in rock and soil types representing different kinds of environments in early Martian history. The remote sensing instrument, ChemCam, determines semi-quantitative elemental compositions using laser induced breakdown spectroscopy (LIBS) to a distance of up to 7 m with an analysis footprint ? 0.5 mm in diameter, and also providing context images with better than 100 microradian resolution. ChemCam is capable of rapidly analyzing nearly all elements including light elements H through O, although atmospheric species can interfere with C and N observations. Using multiple laser pulses per analysis location allows dust to be removed from the analysis locations remotely, and facilitates depth profiles up to 1 mm in rocks and deeper in soils. For tactical operations, in addition to overall reconnaissance, ChemCam analyses will aid in determining placement for arm and sampling operations. Linescans and rasters provide information on sample heterogeneity, and facilitate rapid analysis of layered rock exposures. The arm-mounted APXS is an improved version of its predecessors on MER. The sensitivity is increased by a factor of ~ 3, allowing a rapid analysis in 15 minutes and a full analysis with low detection limits in 3 hours. About 20 elements from Na to Y are determined for typical Martian materials. Bound water or light elements in excess of ~ 5 wt% can be inferred by the scatter peaks of the primary x-ray radiation. Good quality spectra can be taken at temperatures of up to -10 degrees C using the built-in Peltier cooler. The APXS has a high accuracy, only limited by microscopic heterogeneity, and an unprecedented precision to identify elemental trends and local anomalies. The ~ 1.7 cm sample diameter is close to the drill diameter, producing bulk analysis to support powder analysis with SAM and Chemin. APXS sample preparation utilizes the dust removal tool, and analyses are also performed on the drill fines. The complementary analyses from ChemCam and APXS allow efficient selection of the most promising samples for extensive analysis with Chemin and SAM and provide a comparison of the unprocessed sample with the processed powder for these instruments. Both will be used to perform chemostratigraphy studies at Gale to understand Mars' climate and geological history. The talk will report the first Curiosity rover results on the compositions of rocks and soils at Gale crater.

Wiens, R. C.; Gellert, R.; Maurice, S.

2012-12-01

201

Laboratory Inquiry for Determining the Chemical Composition of a Component in a Daily Use Detergent: Sodium Sesquicarbonate  

ERIC Educational Resources Information Center

An inquiry-based laboratory activity to determine the chemical composition of a component in alkaline detergents, sodium sesquicarbonate (SSC), is proposed. On the basis of introductory demonstrations by the instructor on the chemical properties and reactions of SSC, students propose the hypothetical composition of SSC and possible quantitative…

Koga, Nobuyoshi; Kimura, Tomoyasu; Shigedomi, Kana

2011-01-01

202

40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection...Subpart Z of Part 98—Default Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...

2011-07-01

203

40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection...Subpart Z of Part 98—Default Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...

2012-07-01

204

40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection...Subpart Z of Part 98—Default Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...

2013-07-01

205

40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin  

...2014-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection...Subpart Z of Part 98—Default Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...

2014-07-01

206

Study of Productive Capacities for Production of Forage, Crude Protein and Chemical Composition in Sorghum (Sorghum vulgare P. ) Hybrids  

Microsoft Academic Search

KERTIKOV, T., 2007. Study of productive capacities for production of forage, crude protein and chemical composition in Sorghum (Sorghum vulgare P.) hybrids.Bulg. J. Agric. Sci, 13: 281-289 The objective was to study the productive capacities for production of forage, crude protein and chemical composition in sorghum (Sorghum vulgare P.) hybrids. The trials were laid out in Second experimental field in

T. KERTIKOV

207

Huygens/ACP: an instrument for aerosols chemical composition measurements  

NASA Astrophysics Data System (ADS)

The Aerosol Collector Pyrolyzer (ACP) which will be used aboard the Huygens probe is introduced. The scientific objectives, scientific rationale, and a technical description of the ACP are given. The ACP will sample the aerosols of the Titan's atmosphere in two regions, 160 to 60 and 60 to 25 km, respectively. In the first region, it will collect aerosol particles absorbed by a complex core (organic polymers) coated with absorbed or condensed molecules. The second collect will sample larger aerosols and the N2-CH4 droplets. In each sampling, the particles are collected on a metallic filter through which the atmospheric gas is pumped. The filter is then inserted into an oven connected to the Gas Chromatograph Mass Spectrometer (GCMS) Experiment which analyzes the gases produced during the heating of the samples. For each sample it will be possible to bring information on the nature and abundance of the volatile components contained in the particles and/or the composition of the photochemical core.

Israel, Guy; Chassefiere, E.; Niemann, Hasso B.; Boon, Jaap J.; Mueller, Christian; Raulin, Francois; Cabane, M.; Sable, Claude

1992-04-01

208

Chemical composition and antioxidant activity of Strobilanthes crispus leaf extract.  

PubMed

This study investigated the components present in and the total antioxidant activity of leaves of Strobilanthes crispus (L.) Bremek or Saricocalyx crispus (L.) Bremek (Acanthacea). Proximate analyses and total antioxidant activity using ferric thiocyanate and thiobarbituric acid methods were employed. Minerals content was determined using the atomic absorption spectrophotometer, whereas the water-soluble vitamins were determined by means of the UV-VIS spectrophotometer (vitamin C) and fluorimeter (vitamins B(1) and B(2)). Catechin, tannin, caffeine, and alkaloid contents were also studied. All data were compared to the previously reported results of Yerbamate, green tea, black tea, and Indian tea. The dried leaves contained a high amount of total ash (21.6%) as a result of a high amount of minerals including potassium (51%), calcium (24%), sodium (13%), iron (1%), and phosphorus (1%). High content of water-soluble vitamins (C, B(1), and B(2)) contributed to the high antioxidant activity of the leaves. The leaves also contained a moderate amount of other proximate composition as well as other compounds such as catechins, alkaloids, caffeine, and tannin, contributing further to the total antioxidant activity. Catechins of Strobilanthes crispus leaves showed highest antioxidant activity when compared to Yerbamate and vitamin E. Consumption of the leafy extract daily (5 g/day) as an herbal tea could contribute to the additional nutrients and antioxidants needed in the body to enhance the defense system, especially toward the incidence of degenerative diseases. PMID:11137889

Ismail; Manickam; Danial; Rahmat; Yahaya

2000-11-01

209

Chemical compositions and classifica tion of five thermally altered carbonaceous chondrites  

NASA Astrophysics Data System (ADS)

To establish the chemical group provenance of the five thermally altered carbonaceous chondrites Asuka (A-) 881551, Asuka-882113, Elephant Moraine (EET) 96026, Mulga (west), and Northwest Africa (NWA) 3133, we quantified 44 trace elements in each of them. We also analyzed Larkman Nunatak (LAR) 04318 (CK4), Miller Range (MIL) 090001 (CR2), Roberts Massif (RBT) 03522 (CK5) as reference samples as their chemical group affinity is already recognized. We conclude that Asuka-881551, Asuka-882113, and Mulga (west) are thermally metamorphosed CK chondrites. Compositionally, Elephant Moraine 96026 most resembles the CV chondrites. NWA 3133 is the most significantly thermally altered carbonaceous chondrite in our suite of samples. It is completely recrystallized (no chondrules or matrix remain), but its bulk composition is consistent with a CV-CK clan provenance. The thermally labile element (e.g., Se, Te, Zn, and Bi) depletion in NWA 3133 indicates a chemically open system during the heating episode. It remains unclear if the heat necessary for its thermal alteration of NWA 3133 was due to the decay of 26Al or was impact related. Finally, we infer that MIL 090001, Mulga (west), and NWA 3133 show occasional compositional signatures indicative of terrestrial alteration. The alteration is especially evident within the elements Sr, Ba, La, Ce, Th, U, and possibly Sb. Despite the alteration, we can still confidently place each of the altered chondrites within an established chemical group or clan.

Noronha, Bianca A.; Friedrich, Jon M.

2014-08-01

210

Chemical Composition of Martian Soil and Rocks: Complex Mixing and Sedimentary Transport  

NASA Technical Reports Server (NTRS)

Chemical compositions of Martian soil and rocks indicate complex mixing relationships. Mixing of rock and soil clearly takes place and explains some of the chemical variation because sulfur, chlorine, magnesium, and perhaps iron are positively correlated due to their control from a secondary 'sedimentary' mineralogy (e.g., Mg- and possibly Fe-sulfate; Fe-oxides) that is present within the soils. Certain deviations from simple soil-rock mixing are consistent with mineralogical fractionation of detrital iron and titanium oxides during sedimentary transport.

McLennan, Scott M.

2000-01-01

211

Chemical composition of SF6 low-pressure plasma in magnetic field  

NASA Astrophysics Data System (ADS)

The chemical composition of a low-pressure SF6 plasma in a homogeneous magnetic field is studied using a one-dimensional fluid model. This model takes into account the magnetization of electrons and light negative ions F-. The influence of different parameters such as gas pressure, heating power and magnetic field strength is studied within a parameter range of interest for negative ion sources. The scheme of plasma chemical reactions is analysed in order to identify the main reactions responsible for the generation and decay of plasma species. This sensitivity analysis shows that the scheme of reactions can be significantly simplified.

Levko, D.; Garrigues, L.; Hagelaar, G. J. M.

2014-01-01

212

Simulating the evolution of the chemical composition of the 1988/89 winter vortex  

NASA Technical Reports Server (NTRS)

During the 1988/89 Airborne Arctic Stratospheric Expedition (AASE) observations of the chemical composition and aerosol characteristics of the winter vortex were obtained from a NASA ER-2 aircraft. In this paper we present interpretations of observations obtained on three ER-2 flights using a Lagrangian coupled photochemical-microphysical model. It is argued that observations obtained on Jaunary 16 and 19, and February 10, represent different stages of the chemical evolution of the vortex, from the early stages of chlorine release, the onset of denitrification and the intensively processed state.

Jones, R. L.; Mckenna, D. S.; Poole, L. R.; Solomon, S.

1990-01-01

213

Acetylcholinesterase inhibitory activity and chemical composition of commercial essential oils.  

PubMed

Commercially available essential oils extracted from Artemisia dracunculus L., Inula graveolens L., Lavandula officinalis Chaix, and Ocimum sanctum L. and the components of these oils were screened by the microplate assay method for determining their acetylcholinesterase (AChE) inhibitory activity. The composition profiles of the oils were characterized by gas chromatography-mass spectrometry (GC-MS) analysis, and the relationships between the oil components and the AChE inhibitory activity of the oils were outlined. The results showed that all of the oils, except that of A. dracunculus from Hungary, exhibited AChE inhibitory activity, and the A. dracunculus oil from France showed the most potent inhibitory activity [50% inhibition concentration (IC(50)) = 0.058 mg/mL]. The AChE inhibitory activity of I. graveolens oil has not been reported to date, and this study is the first to reveal this activity in the oil. Among the essential oil components, five components, namely, 1,8-cineole, ?-pinene, eugenol, ?-terpineol, and terpinen-4-ol, showed AChE inhibitory activity, with IC(50) values of 0.015, 0.022, 0.48, 1.3, and 3.2 mg/mL, respectively. Eugenol, in particular, was found to be a potent AChE inhibitor along with determination of the IC(50) value, a finding that has been reported for the first time in this study. However, the ratio of the contribution of the active components, including a novel AChE inhibitor, to the observed AChE inhibitory activity of the essential oils was not very high. The results of this study raise concerns about the AChE inhibitory activity of widely produced and readily accessible commercial essential oils. PMID:19358605

Dohi, Satomi; Terasaki, Masanori; Makino, Masakazu

2009-05-27

214

Chemical composition of urban airborne particulate matter in Ulaanbaatar  

NASA Astrophysics Data System (ADS)

Atmospheric pollution caused by airborne particulate matter in the winter season in Ulaanbaatar, Mongolia is a very serious problem. However, there is a complete lack of scientific observation data to define the situation prior to any remediation. PM10 and PM2.5 average monthly values obtained by continuous monitoring showed the concentrations of particles of both size categories exceeded 100 ?g m-3 during November to February (winter). PM10 particles were sampled with filters in January (i.e. during the heating period) and June (i.e.non-heating period) of 2008 in central Ulaanbaatar. To determine the composition of urban airborne particulate matter we analyzed a range of ionic components, multiple elements including heavy metals, and organic and inorganic carbon (soot). We also measured the stable carbon isotope ratio of the soot. Total carbon (sum of organic carbon and inorganic carbon) accounted for 47% of the mass of the PM10 during the heating period and 33% during the non-heating period, and was the largest component of urban airborne particulate matter in Ulaanbaatar. Stable isotope ratios (?13C) of soot generated during the heating period (-23.4 ± 0.2‰) approximated the ratios for coal used in Ulaanbaatar (-21.3 to -24.4‰), while the ratios during the non-heating period (-27.1 ± 0.4‰) were clearly different from the coal values. In the heating period, a very high correlation was observed between soot and organic carbon, SO42-, NO3-, F-, Zn, As, and Pb, and we concluded that they were derived from coal combustion along with soot. In addition, the concentrations and their ratios relative to each other of Al, Fe, Ca, K, Na, Mg, and Mn hardly differed between the heating period and the non-heating period, and it was concluded that they were derived from soil dust.

Nishikawa, Masataka; Matsui, Ichiro; Batdorj, Dashdondog; Jugder, Dulam; Mori, Ikuko; Shimizu, Atsushi; Sugimoto, Nobuo; Takahashi, Katsuyuki

2011-10-01

215

Chemical composition and liberation characterization of printed circuit board comminution fines for beneficiation investigations.  

PubMed

Chemical composition and liberation are critical attributes in characterizing a resource stock for beneficiation investigations. Though end-of-life printed circuit board is recognized as a valuable secondary resource stock, no procedural standard exists for the determination of its chemical composition, nor for the -75 microm fines generated during its comminution. The effect of the digestion procedure on the final assays in wet spectroscopic analyses was assessed in this work. Liberation was also explored against literature background. Determination of assays of all constituent elements in printed circuit board comminution fines was found to require comparison of data from more than one digestion condition, while composite particles still persist at the fines sizes, though very few. The discussion reflects how these impact the beneficiation investigations. PMID:19329293

Ogunniyi, I O; Vermaak, M K G; Groot, D R

2009-07-01

216

Chemical composition and antibacterial activity of Opuntia ficus-indica f. inermis (cactus pear) flowers.  

PubMed

Opuntia ficus-indica f. inermis (cactus pear) flowers have wide application in folk medicine. However, there are few reports focusing on their biological activity and were no reports on their chemical composition. The nutrient composition and hexane extracts of Opuntia flowers at 4 flowering stages and their antibacterial and antifungal activities were investigated. The chemical composition showed considerable amounts of fiber, protein, and minerals. Potassium (K) was the predominant mineral followed by calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), and zinc (Zn). The main compounds in the various hexane extracts were 9.12-octadecadienoic acid (29-44%) and hexadecanoic acid (8.6-32%). The antibacterial activity tests showed that O. inermis hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, making this botanical source a potential contender as a food preservative or food control additive. PMID:24650181

Ennouri, Monia; Ammar, Imene; Khemakhem, Bassem; Attia, Hamadi

2014-08-01

217

Composition and chemical variability of leaf oil of Myrtus communis from north-eastern Algeria.  

PubMed

The chemical composition of 27 oil samples of Myrtus communis isolated from leaves collected in three locations in north-eastern Algeria was investigated by GC(RI) and 13C NMR spectroscopy. Yields ranged between 0.2-1.2% (w/w). The chemical composition of the oils was largely dominated by monoterpene hydrocarbons, with alpha-pinene (40.5-64.0%), 1,8-cineole (10.9-29.1%) and limonene (6.7-8.2%) being the major compounds. In all the samples, 3,3,5,5,8,8-hexamethyl-7-oxabicyclo[4.3.0]non-1(6)-ene-2,4-dione was identified (0.8-1.5%). The composition is similar to that reported for myrtle oils from Corsica, Sardinia and Tunisia, but differed from that of Moroccan and Spanish myrtle oils. PMID:21121268

Bouzabata, Amel; Boussaha, Faffani; Casanova, Joseph; Tomi, Félix

2010-10-01

218

Chemical composition and antioxidant activity of certain Morus species  

PubMed Central

In the present work, the fruits of four Morus species, namely Morus alba (white mulberry), Morus nigra (black mulberry), Morus laevigata (large white fruit), and Morus laevigata (large black fruit), were analyzed for proximate composition, essential minerals, and antioxidant potentials. For this purpose, the ripe fruits were collected from the northern regions of Pakistan. The major nutritional components (moisture, ash, lipids, proteins, fibres, carbohydrates, and total sugar) were found to be in the suitable range along with good computed energy. Total dry weight, pH, and titratable acidity (percent citric acid) were (17.60±1.94)–(21.97±2.34) mg/100 g, (3.20±0.07)–(4.78±0.15), and (0.84±0.40)%–(2.00±0.08)%, respectively. Low riboflavin (vitamin B2) and niacin (vitamin B3) contents were recorded in all the fruits, while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW). The mulberry fruits were rich with regard to the total phenol and alkaloid contents, having values of (880±7.20)–(1650±12.25) mg/100 g FW and (390±.22)–(660±5.25) mg/100 g FW, respectively. Sufficient quantities of essential macro-(K, Ca, Mg, and Na) and micro-(Fe, Zn, and Ni) elements were found in all the fruits. K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g, while Ca, Na, and Mg contents were (440±3.21)–(576±7.37), (260±3.86)–(280±3.50), and (24±3.51)–(360±4.20) mg/100 g, respectivly. The decreasing order of micro-minerals was Fe>Zn>Ni. The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits. Based on the results obtained, mulberry fruits were found to serve as a potential source of food diet and natural antioxidants. PMID:21121077

Imran, Mohammad; Khan, Hamayun; Shah, Mohibullah; Khan, Rasool; Khan, Faridullah

2010-01-01

219

Chemical composition and antioxidant activity of certain Morus species.  

PubMed

In the present work, the fruits of four Morus species, namely Morus alba (white mulberry), Morus nigra (black mulberry), Morus laevigata (large white fruit), and Morus laevigata (large black fruit), were analyzed for proximate composition, essential minerals, and antioxidant potentials. For this purpose, the ripe fruits were collected from the northern regions of Pakistan. The major nutritional components (moisture, ash, lipids, proteins, fibres, carbohydrates, and total sugar) were found to be in the suitable range along with good computed energy. Total dry weight, pH, and titratable acidity (percent citric acid) were (17.60±1.94)-(21.97±2.34) mg/100 g, (3.20±0.07)-(4.78±0.15), and (0.84±0.40)%-(2.00±0.08)%, respectively. Low riboflavin (vitamin B(2)) and niacin (vitamin B(3)) contents were recorded in all the fruits, while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW). The mulberry fruits were rich with regard to the total phenol and alkaloid contents, having values of (880±7.20)-(1650±12.25) mg/100 g FW and (390±3.22)-(660±5.25) mg/100 g FW, respectively. Sufficient quantities of essential macro-(K, Ca, Mg, and Na) and micro-(Fe, Zn, and Ni) elements were found in all the fruits. K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g, while Ca, Na, and Mg contents were (440±3.21)-(576±7.37), (260±3.86)-(280±3.50), and (240±3.51)-(360±4.20) mg/100 g, respectivly. The decreasing order of micro-minerals was Fe>Zn>Ni. The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits. Based on the results obtained, mulberry fruits were found to serve as a potential source of food diet and natural antioxidants. PMID:21121077

Imran, Mohammad; Khan, Hamayun; Shah, Mohibullah; Khan, Rasool; Khan, Faridullah

2010-12-01

220

Mantle Metasomatism in Mars: Evidence from Bulk Chemical Compositions of Martian Basalts  

NASA Technical Reports Server (NTRS)

Bulk compositions of martian meteorite basalts suggest that they formed from a highly depleted mantle that was variably metasomatised and enriched in incompatible elements. These results are consistent with radio-isotope results. Bulk chemical compositions of basaltic rocks retain clues and tracers to their origins and histories. Interpretations of bulk compositions are not so straight-forward as once envisioned, because real-world magmatic processes can be far from theoretical simple models like one-stage partial melting or closed-system fractional crystallization. Yet, bulk chemistry can shed a broad (if dim) light on Martian basalt petrogenesis that complements the sharply focussed illumination of radio-isotope systematics.

Treiman, A. H.

2003-01-01

221

Physico-mechanical properties of chemically treated palm and coir fiber reinforced polypropylene composites.  

PubMed

In this work, palm and coir fiber reinforced polypropylene bio-composites were manufactured using a single extruder and injection molding machine. Raw palm and coir were chemically treated with benzene diazonium salt to increase their compatibility with the polypropylene matrix. Both raw and treated palm and coir fiber at five level of fiber loading (15, 20, 25, 30 and 35 wt.%) was utilized during composite manufacturing. Microstructural analysis and mechanical tests were conducted. Comparison has been made between the properties of the palm and coir fiber composites. Treated fiber reinforced specimens yielded better mechanical properties compared to the raw composites, while coir fiber composites had better mechanical properties than palm fiber ones. Based on fiber loading, 30% fiber reinforced composites had the optimum set of mechanical properties. PMID:19477124

Haque, Md Mominul; Hasan, Mahbub; Islam, Md Saiful; Ali, Md Ershad

2009-10-01

222

Influence of different parameters on the chemical composition of warm Neptunes  

NASA Astrophysics Data System (ADS)

We developed a 1D photo-thermochemical model to study the atmosphere of warm exoplanets. The chemical scheme used in this model is completely new in planetology and has been constructed in collaboration with specialists of combustion. It has been validated as a whole through experiments on a large range of temperature (300 - 2500 K) and pressure (1 mbar - 100 bar), allowing to study a wide variety of exoplanets. We have used this chemical model to study the atmosphere of two warm Neptunes, GJ3470b and GJ436b, and the influence of different parameters (vertical mixing, metallicity, temperature,...) on their chemical composition. We present here the results obtained in these studies.

Venot, O.; Ag´undez, M.; Selsis, F.; Tessenyi, M.; Decin, L.

2014-12-01

223

Expanding current knowledge on the chemical composition and antioxidant activity of the genus lactarius.  

PubMed

Despite the presence of toxic compounds in inedible mushrooms, the question whether the chemical nutrients and non-nutrients compositions in edible and inedible Lactarius species are similar remains unanswered. To answer this question, Lactarius citriolens Pouzar and Lactarius turpis (Weinm.) Fr., two inedible species, were studied in order to obtain information about their chemical composition and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. citriolens and L. turpis methanolic extracts were tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). The composition of macronutrients varied among the two species, but the profiles were similar between them and among other Lactarius species; L. citriolens gave the highest energy contribution, saturated fatty acids and organic acids, while the L. turpis sample was richer in free sugars, mono- and polyunsaturated fatty acids, tocopherols and phenolic compounds. L. turpis methanolic extract showed the highest antioxidant activity. The absence of hepatoxicity of the methanolic extracts was confirmed in porcine liver primary cells (in vitro conditions). The present study provided new information about wild L. citriolens and L. turpis, comparing their chemical composition and antioxidant properties with other Lactarius species, and expanding the knowledge about this genus. PMID:25514055

Vieira, Vanessa; Barros, Lillian; Martins, Anabela; Ferreira, Isabel C F R

2014-01-01

224

The use of chemical composition data in waste management planning - A case study  

SciTech Connect

As the waste industry continues to move from a disposal-based system to one based on a combination of recovery options, the need for information on the composition of waste increases and this is reflected by the amount of information on the physical composition of municipal solid wastes that is now available. However, there is far less information on the chemical composition of municipal solid waste. The results from a number of chemical surveys from Europe are compared and show a reasonable degree of agreement, but several problems were identified with the data. Chemical and physical compositional data are combined in a case study example to investigate the flow of key potential pollutants in an integrated solid waste management system that uses materials recycling, composting, incineration and landfilling. This case study has shown that an integrated waste management strategy diverts lead and cadmium away from composting and recycling to incineration, which effectively isolates these elements from the environment through efficient capture of the pollutants followed by secure landfilling or recycling of the residues. However, further work is needed to determine the distribution of mercury in incineration residues and its fate when the residues are landfilled.

Burnley, S.J. [Department of Environmental and Mechanical Engineering, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom)], E-mail: s.j.burnley@open.ac.uk

2007-07-01

225

Chemical composition of the volatile oil from Zanthoxylum avicennae and antimicrobial activities and cytotoxicity  

PubMed Central

Background: Through literature retrieval, there has been no report on the research of the chemical components in Zanthoxylum avicennae (Lam.) DC. This paper extracted and determined the chemical components of the volatile oil in Z. avicennae, and at the same time, measured and evaluated the bioactivity of the volatile oil in Z. avicennae. Materials and Methods: We extract the volatile oil in Z. avicennae by steam distillation method, determined the chemical composition of the volatile oil by GC-MS coupling technique, and adopt the peak area normalization method to measured the relative percentage of each chemical composition in the volatile oil. Meanwhile, we use the Lethal-to-prawn larva bioactivity experiment to screen the cytotoxicity activities of the volatile oil in Z. avicennae, and using the slanting test-tube experiment to determine and evaluate its antibacterial activities in vitro for the eight kinds of plant pathogenic fungi in the volatile oil of the Z. avicennae. Results: The results show that 68 kinds of compounds are determined from the volatile oil of Z. avicennae. The determined part takes up 97.89% of the total peak area. The main ingredients in the volatile oil of Z. avicennae are sesquiterpenoids and monoterpene. The test results show that the volatile oil in Z. avicennae has strong antibacterial activities and cytotoxicity, with the strongest antibacterial activity against the Rhizoctonia solani AG1-1A. Conclusion: This research results will provide reference data for understanding the chemical composition of the volatile oil in the aromatic plant of Z. avicennae and its bioactivity, and for its further development and application. PMID:24914299

Lin, Yin; Han, Wei; Ge, Wei-chen; Yuan, Ke

2014-01-01

226

Effect of chemical degradation followed by toothbrushing on the surface roughness of restorative composites  

PubMed Central

Objectives The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram). Material and methods Twenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly allocated to 4 groups (n=5), according to the food-simulating liquid in which they were immersed for 7 days at 37ºC: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra, µm) were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM). Results The statistical analysis (ANOVA with cofactor / Tukey's test, ?=5%) detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. Conclusions The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media. PMID:21308289

VOLTARELLI, Fernanda Regina; dos SANTOS-DAROZ, Claudia Batitucci; ALVES, Marcelo Corrêa; CAVALCANTI, Andrea Nóbrega; MARCHI, Giselle Maria

2010-01-01

227

Synthesis and physico-chemical characterization of a polysialate-hydroxyapatite composite for potential biomedical application  

NASA Astrophysics Data System (ADS)

New composite materials based on aluminosilicate materials were developed to be used in orthopaedic or maxillo-facial surgery. They are called geopolymers or polysialate-siloxo (PSS) and were studied alone or mixed with hydroxyapatite (HAP). The properties of these materials were investigated for potential use in biological or surgery applications. In this work, the chemistry involved in materials preparation was described. Samples were characterized by some physico-chemical methods like X-ray diffraction (XRD), infrared spectrometry (IR) and electron dispersion X-ray spectrometry (EDX). Results indicate that the mixing hydroxyapatite-geopolymer (PSS) leads to a neutral porous composite material with interesting physico-chemical properties. A preliminary evaluation of its cytotoxicity reveals an harmlessness towards fibroblasts. These properties allow to envisage this association as a potential biomaterial.

Zoulgami, M.; Lucas-Girot, A.; Michaud, V.; Briard, P.; Gaudé, J.; Oudadesse, H.

2002-09-01

228

Chemical compositions of Four B-type Supergiants in the SMC Wing  

E-print Network

High-resolution UCLES/AAT spectra of four B-type supergiants in the SMC South East Wing have been analysed using non-LTE model atmosphere techniques to determine their atmospheric parameters and chemical compositions. The principle aim of this analysis was to determine whether the very low metal abundances ($-$1.1 dex compared with Galactic value) previously found in the Magellanic Inter Cloud region (ICR) were also present in SMC Wing. The chemical compositions of the four targets are similar to those found in other SMC objects and appear to be incompatible with those deduced previously for the ICR. Given the close proximity of the Wing to the ICR, this is difficult to understand and some possible explanations are briefly discussed.

J. -K. Lee; W. R. J. Rolleston; P. L. Dufton; R. S. I. Ryan

2004-10-12

229

Expected gamma-ray emission spectra from the lunar surface as a function of chemical composition  

NASA Technical Reports Server (NTRS)

The gamma rays emitted from the moon or any similar body carry information on the chemical composition of the surface layer. The elements most easily measured are K, U, Th and major elements such as O, Si, Mg, and Fe. The expected fluxes of gamma ray lines were calculated for four lunar compositions and one chondritic chemistry from a consideration of the important emission mechanisms: natural radioactivity, inelastic scatter, neutron capture, and induced radioactivity. The models used for cosmic ray interactions were those of Reedy and Arnold and Lingenfelter. The areal resolution of the experiment was calculated to be around 70 to 140 km under the conditions of the Apollo 15 and 16 experiments. Finally, a method was described for recovering the chemical information from the observed scintillation spectra obtained in these experiments.

Reedy, R. C.; Arnold, J. R.; Trombka, J. I.

1973-01-01

230

Determination of Chemical Compositions on Adult Kidney Stones—A Spectroscopic Study  

NASA Astrophysics Data System (ADS)

The chemical compositions of the kidney stones of both the sexes of patients, aged from 40 to 70, living in and around Chidambaram town are determined by using FT-IR and X-RD technique. The kidney stone samples used in the present study were procured from the Rajah Muthiah Medical College and Hospital, Annamalai University. The FT-IR spectra of different kidney stone samples were recorded in the range of 4000-400 cm-1. By identifying the characteristic frequency, the chemical compositions of the samples are determined. The results analyzed by FTIR technique were confirmed by X-RD method, in which the recorded X-ray diffractogram are compared with JCPDS files using search match method. Further analysis of XRD pattern also reveals the same.

Raju, K.; Rakkappan, C.

2008-11-01

231

Effect of chemical treatment on electrical properties of coir fibre reinforced epoxy composites  

NASA Astrophysics Data System (ADS)

In this paper, the effect of chemical treatment on electrical properties of coir fibre- reinforced epoxy composites has been reported. For this purpose, epoxy composites reinforced with chemically treated coir fibre prepared by hand molding method. Samples were characterized for their electrical properties, such as dielectric constant (e0), and AC conductivity (?ac), at different temperatures and frequencies. It was observed that dielectric constant increases with increase in temperature and decreases with increase in frequency from 5 KHz to 30 kHz. The peak height at the transition temperature decreases with increasing frequency. Electrical characterization of the samples has been done by impedance analyzer. Morphology of the samples has been done by SEM technique. Crystalline nature of the sample has been done by XRD analysis.

Khan, A.; Joshi, S.

2014-09-01

232

Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils.  

PubMed

The aim of the present work was to study the impact of the chemical composition of precipitation on radiocaesium mobility in natural soil. This was done through column studies. Three types of precipitation regimes were studied, representing a natural range found in Norway: Acidic precipitation (southernmost part of the country); precipitation rich in marine cations (highly oceanic coastal areas); and low concentrations of sea salts (slightly continental inland areas). After 50 weeks and a total precipitation supply of ?10 000 L m(-2) per column, results indicate that acidic precipitation increased the mobility of (134)Cs added during the experiment. However, depth distribution of already present Chernobyl fallout (137)Cs was not significantly affected by the chemical composition of precipitation. PMID:24704765

Thørring, H; Skuterud, L; Steinnes, E

2014-08-01

233

Chemical composition and antibacterial activity of essential oil and extracts of Citharexylum spinosum flowers from Thailand.  

PubMed

The chemical composition and antibacterial and antioxidant activities of the essential oil and various solvent extracts of Citharexylum spinosum flowers are reported. The chemical compositions were determined by GC-MS with 151 volatile constituents identified. Methyl benzoate, piperitone, maltol, and maple furanone were the major constituents. All extracts were tested for their antibacterial activity against eight microorganisms. The flower oil had the greatest antibacterial activity against all bacterial strains (MIC values of 31.2 microg/mL), while the other solvent extracts had MIC values ranging from 31.2 to 1000 microg/mL. The essential oil had the highest antioxidant activity and total phenol content with IC50 values of 62.7 and 107.3 microg/mL, respectively. PMID:25026728

Mar, Ae; Pripdeevech, Patcharee

2014-05-01

234

THE EFFECT OF DEGREE OF CORN PROCESSING ON THE CHEMICAL COMPOSITION OF CORN  

Technology Transfer Automated Retrieval System (TEKTRAN)

An experiment was conducted to determine the effect of degree of processing on the chemical composition of corn. Corn was processed by dry rolling to a bulk density of 0.59 kg/L (46 pounds/bushel, DR46) or steam flaking to a bulk density of 0.36 or 0.28 kg/L (28 [SF28] and 22 [SF22] pounds/bushel, ...

235

Structure and chemical composition of layers adsorbed at interfaces with champagne.  

PubMed

The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces. PMID:19813745

Aguié-Béghin, V; Adriaensen, Y; Péron, N; Valade, M; Rouxhet, P; Douillard, R

2009-11-11

236

Comparative investigations of the morphology and chemical composition of the eggshells of Acanthocephala  

Microsoft Academic Search

Eggshells ofMacracanthorhynchus hirudinaceus (Archiacanthocephala) were investigated for their fine structure as well as their chemical composition. The acanthor larvae are surrounded by four eggshells (E1–4) separated by interstices of low electron density (G1–4). As these envelopes are secreted in different sequences and are reinforced to different degrees, their appearance varies throughout development. The outermost eggshell (E1) of this species has

W. Peters; H. Taraschewski; Inge Latka

1991-01-01

237

Temperature dependencies of sensitivity and surface chemical composition of SnO x gas sensors  

Microsoft Academic Search

The electrical resistivity response to CO gas exposure versus temperature has been measured for different types of SnOx-based gas sensors. The chemical composition of the sensor surfaces and the electronic structure of the valence band are investigated by X-ray photoelectron spectroscopy and scanning Auger microscopy technique, with the aim of explaining resistivity changes in terms of the surface oxidation\\/reduction mechanism.

G. Gaggiotti; A. Galdikas; G. Mattogno

1995-01-01

238

Chemical composition and leaching characteristics of granules made of wood ash and dolomite  

Microsoft Academic Search

In 1995, the central heating plant Draken in Kalmar, Sweden, started manufacturing a granular ash product for nutrient recycling\\u000a to forest soil, instead of dumping the ash in landfills. Chemical composition, leaching and dissolution characteristics were\\u000a determined for the Draken wood ash, the dolomite used in granule manufacturing and the final granule product. The heavy metal concentrations in fly\\u000a ash

S. L. Holmberg; B. B. Lind; T. Claesson

2000-01-01

239

Chemical Composition of Raw Milk and Heavy Metals Behavior During Processing of Milk Products  

Microsoft Academic Search

Whole buffalo's and cow's milk as well as dairy products manufactured from them were analyzed for chemical composition and metal contents. Buffalo's milk showed higher levels of fat (4.9%), total protein (3.6%), total solids (13.4%) and ash (0.76%) than cow's milk (3.2, 3.2, 12.1 and 0.65%, respectively). Also, higher levels were detected in pasteurized and sterilized buffalo's milk. However, lactose

A. En; M. A. Abou Donia; N. S. Abd-Rabou; A. A. K. Abou-Arab; M. H. El-Senait

240

Adverse surface interactions between one-bottle light-cured adhesives and chemical-cured composites  

Microsoft Academic Search

Objectives: This study examined the effect of one-bottle adhesives with different acidities on bonding to chemical-cured and light-cured resin composites.Methods: Twenty-four non-carious human third molars were divided into eight groups. A flat dentin surface was created for each tooth. Acid-conditioned dentin surfaces were bonded with Prime&Bond NT (Dentsply), OptiBond SOLO (Kerr), Single Bond (3M) or One-Step (Bisco). Each adhesive group

Anna Marie E Sanares; Anut Itthagarun; Nigel M King; Franklin R Tay; David H Pashley

2001-01-01

241

Chemical composition and antibacterial activity of Pinus halepensis Miller growing in West Northern of Algeria  

PubMed Central

Objective To find new bioactive natural products, the chemical composition and to sudy the antibacterial activity of essential oil components extracted from the aerial parts of the Algerian aromatic plant Pinus halepensis Miller (P. halepensis) (needles, twigs and buds). Methods The essential oil used in this study was isolated by hydrodistillation using a Clevenger-type apparatus according to the European Pharmacopoeia. The chemical composition was investigated using GC-retention indices (RI) and GC-MS. Results Forty-nine compounds, representing 97.9% of the total collective oil, were identified. Essential oil was dominated by hydrocarbon compounds (80.6%) especially monoterpenes (65.5%). The major compounds from ten oils stations were: myrcene (15.2%-32.0%), ?-pinene (12.2%-24.5%), E-?-caryophyllene (7.0%-17.1%), terpinolene (1.8%-13.3%), 2-phenyl ethyl isovalerate (4.8%-10.9%), terpinene-4-ol (1.0%-8.2 %) and sabinene (1.5%-6.3%). The intra-species variations of the chemical compositions of P. halepensis aerial parts essential oils from ten Algerian sample locations were investigated using statistical analysis. Essential oil samples were clustered in 2 groups by hierarchical cluster analysis, according to their chemical composition. The essential oil revealed an interesting antimicrobial effect against Lysteria monocytogenes, Enterococcus faecalis, Pseudomonas aeruginosa, Acinetobacter baumanii, Citrobacter freundii and Klebsiella pneumoniae. Conclusions These results suggest that the essential oil from P. halepensis may be a new potential source as natural antimicrobial applied in pharmaceutical and food industries.

Fekih, Nadia; Allali, Hocine; Merghache, Salima; Chaïb, Faïza; Merghache, Djamila; El Amine, Mohamed; Djabou, Nassim; Muselli, Alain; Tabti, Boufeldja; Costa, Jean

2014-01-01

242

In-vitro anti- Vibrio spp. activity and chemical composition of some Tunisian aromatic plants  

Microsoft Academic Search

The chemical composition of five aromatic plants (Mentha longifolia, M. pulegium, Eugenia caryophyllata, Thymus vulgaris and Rosmarinus officinalis) frequently used in food preparation in Tunisia was analysed by GC-MS. The antimicrobial effect of the essential oils obtained\\u000a from these plants was tested against Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio fluvialis strains. Thyme oil exhibited a high level of

Mejdi Snoussi; Hafedh Hajlaoui; Emira Noumi; Donatella Usai; Leonardo Antonio Sechi; Stefania Zanetti; Amina Bakhrouf

2008-01-01

243

Chemical composition distribution analysis of photoresist copolymers and influence on ArF lithographic performance  

Microsoft Academic Search

For getting information about the distribution of chemical composition, several model polymers were prepared under different polymerization conditions and were measured by critical adsorption point-liquid chromatography (CAP-LC). In the copolymer system of 8- and 9- (4-oxatricyclo[5.2.1.02,6]decane-3-one) acrylate (OTDA) and 2-ethyl-2-adamantyl methacrylate (EAdMA), the peak shapes of the CAP-LC chromatogram varied according to the polymerization condition although they indicated same molecular

Hikaru Momose; Atsushi Yasuda; Akifumi Ueda; Takayuki Iseki; Koichi Ute; Takashi Nishimura; Ryo Nakagawa; Tatsuki Kitayama

2007-01-01

244

The Effects of Daptomycin on Chemical Composition and Morphology of Staphylococcus aureus  

Microsoft Academic Search

The effects of daptomycin on Staphylococcus aureus morphology and chemical composition were studied by comparative analyses of susceptible and daptomycin-resistant strains. The resistant strains were developed from wild-type (WT) susceptible cells by stepwise selection to increasingly higher levels of daptomycin. The minimal inhibitory concentrations of penicillin, streptomycin, tetracycline, and erythromycin were similar among resistant and susceptible strains. Daptomycin-resistant strains were

Robert S. Conrad; Marsha J. Howard; Roger C. Garrison; Stacey Winters; David A. Henderson

1998-01-01

245

Effect of different technological processes on the chemical composition of myrtle ( Myrtus communis L.) alcoholic extracts  

Microsoft Academic Search

Several technological processes were applied to improve the extraction efficiency in the production of myrtle (Myrtus communis L.) liqueur. The variations in the chemical composition of myrtle hydroalcoholic extracts were monitored in a laboratory\\u000a scale for 40 days after the application of: double dose of berries; ultrasonic extraction; enzymes, to improve either the\\u000a color or aroma extraction; and atmosphere saturated with

Carlo I. G. Tuberoso; Andrea Barra; Paolo Cabras

2008-01-01

246

Chemical composition and antifungal activity of essential oil of Chrysactinia mexicana gray.  

PubMed

The chemical composition of the essential oil of Chysactinia mexicana was analyzed by gas chromatography-mass spectrometry. Seventeen compounds were characterized; eucalyptol (41.3%), piperitone (37.7%), and linalyl acetate (9.1%) were found as the major components. The essential oil of leaves and piperitone completely inhibited Aspergillus flavus growth at relatively low concentrations (1.25 and 0.6 mg/mL, respectively). PMID:15913293

Cárdenas-Ortega, Norma C; Zavala-Sánchez, Miguel A; Aguirre-Rivera, J Rogelio; Pérez-González, Cuauhtémoc; Pérez-Gutiérrez, Salud

2005-06-01

247

GC-MS studies of the chemical composition of two inedible mushrooms of the genus Agaricus  

PubMed Central

Background Mushrooms in the genus Agaricus have worldwide distribution and include the economically important species A. bisporus. Some Agaricus species are inedible, including A. placomyces and A. pseudopratensis, which are similar in appearance to certain edible species, yet are known to possess unpleasant odours and induce gastrointestinal problems if consumed. We have studied the chemical composition of these mushrooms using GC-MS. Results Our GC-MS studies on the volatile fractions and butanol extracts resulted in the identification of 44 and 34 compounds for A. placomyces and A. pseudopratensis, respectively, including fatty acids and their esters, amino acids, and sugar alcohols. The most abundant constituent in the volatiles and butanol were phenol and urea respectively. We also identified the presence of ergosterol and two ?7-sterols. In addition, 5?,8?-Epidioxi-24(?)-methylcholesta-6,22-diene-3?-ol was isolated for the first time from both mushrooms. Our study is therefore the first report on the chemical composition of these two species. Conclusion The results obtained contribute to the knowledge of the chemical composition of mushrooms belonging to the Agaricus genus, and provide some explanation for the reported mild toxicity of A. placomyces and A. pseudopratensis, a phenonomenon that can be explained by a high phenol content, similar to that found in other Xanthodermatei species. PMID:18096035

Petrova, Assya; Alipieva, Kalina; Kostadinova, Emanuela; Antonova, Daniela; Lacheva, Maria; Gjosheva, Melania; Popov, Simeon; Bankova, Vassya

2007-01-01

248

Chemical composition and antioxidant activity of a Lebanese plant Euphorbia macroclada schyzoceras  

PubMed Central

Objective To determine the chemical composition, total phenolic and total flavonoid contents of the crude extracts from leaves and stems of a Lebanese plant Euphorbia macroclada schyzoceras (E. macroclada), and to evaluate their antioxidant potential using DPPH, H2O2, and chelating of ferrous ions tests. Methods Quantification of the total phenolic and total flavonoid contents of the crude extracts from leaves and stems and the antioxidant activities were evaluated using spectrophotometric analyses. The chemical composition has been estimated using different techniques such as IR, LC/MS and NMR. Results Ethanolic extract from leaves of E. macroclada was better than aqueous extract and showed higher content in total phenolic and total flavonoid than found in the stems. On the other hand, using DPPH and H2O2 tests, this extract from leaves showed higher antioxidant capacity than aqueous extract. However, using the chelating of ferrous ions test, the antioxidant activity of the aqueous extract of both stems and leaves was stronger than that of ethanolic once. The chemical composition of the whole plant showed the presence of some aromatic compounds and fatty acids. Conclusions Both ethanolic and water extracts from both parts of this plant are effective and have good antioxidant power. So, this plant can be used in the prevention of a number of diseases related to oxidative stress. PMID:23836193

Farhan, Hussein; Rammal, Hassan; Hijazi, Akram; Daher, Ahmad; Reda, Mohamad; Annan, Hussein; Chokr, Ali; Bassal, Ali; Badran, Bassam; Ghaloub, Abdulameer Nasser

2013-01-01

249

Chemical composition and lipoxygenase activity in soybeans (Glycine max L. Merr.) submitted to gamma irradiation  

NASA Astrophysics Data System (ADS)

Soybeans are an important food due to their functional and nutritional characteristics. However, consumption by western populations is limited by the astringent taste of soybeans and their derivatives which results from the action of lipoxygenase, an enzyme activated during product processing. The aim of this study was to evaluate the effect of gamma irradiation on the chemical composition and specific activity of lipoxygenase in different soybean cultivars. Soybeans were stored in plastic bags and irradiated with doses of 2.5, 5 and 10 kGy. The chemical composition (moisture, protein, lipids, ashes, crude fiber, and carbohydrates) and lipoxygenase specific activity were determined for each sample. Gamma irradiation induced a small increase of protein and lipid content in some soybean cultivars, which did not exceed the highest content of 5% and 26%, respectively, when compared to control. Lipoxygenase specific activity decreased in the three cultivars with increasing gamma irradiation dose. In conclusion, the gamma irradiation doses used are suitable to inactivate part of lipoxygenase while not causing expressive changes in the chemical composition of the cultivars studied.

Barros, Érica Amanda de; Broetto, Fernando; Bressan, Dayanne F.; Sartori, Maria M. P.; Costa, Vladimir E.

2014-05-01

250

Delicious Chemicals.  

ERIC Educational Resources Information Center

This paper presents an approach to chemistry and nutrition that focuses on food items that people consider delicious. Information is organized according to three categories of food chemicals that provide energy to the human body: (1) fats and oils; (2) carbohydrates; and (3) proteins. Minerals, vitamins, and additives are also discussed along with…

Barry, Dana M.

251

Chemical Mahjong  

ERIC Educational Resources Information Center

An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

Cossairt, Travis J.; Grubbs, W. Tandy

2011-01-01

252

Chemical Evolution  

E-print Network

In this series of lectures we first describe the basic ingredients of galactic chemical evolution and discuss both analytical and numerical models. Then we compare model results for the Milky Way, Dwarf Irregulars, Quasars and the Intra-Cluster- Medium with abundances derived from emission lines. These comparisons allow us to put strong constraints on the stellar nucleosynthesis and the mechanisms of galaxy formation.

Francesca Matteucci

2007-04-05

253

An analysis of flow, temperature, and chemical composition distortion in gas sampling through an orifice during chemical vapor deposition  

E-print Network

an orifice during chemical vapor deposition Mark T. Swiharta) and Steven L. Girshick Department of Mechanical disturbance due to sampling causes the conditions at the mouth of the orifice to be different from those at the growth surface. Unless the orifice diameter is suffici- ently small, relative to the thickness

Swihart, Mark T.

254

Refinery piping fires resulting from variations in chemical composition of piping materials  

SciTech Connect

A number of refinery fires in recent years are traceable to variations in the chemical composition of piping materials. These fires are typically more destructive than those due to other causes and can take place without warning. Some, but not all, were the result of the inadvertent use of carbon steel in alloy steel piping systems. Others were the result of alloy welds in carbon steel systems while still others were due to variations in residual elements leading to anomalous corrosion behavior. Recommendations are given on areas of refinery units where the greatest need for close control of material composition exists.

Setterlund, R.B. [Metallurgical Consultants, Inc., Houston, TX (United States)

1996-07-01

255

Exploring the Chemical Sensitivity of a Carbon Nanotube/Green Tea Composite  

PubMed Central

Single-walled carbon nanotubes (SWNTs) possess unique electronic and physical properties, which make them very attractive for a wide range of applications. In particular, SWNTs and their composites have shown a great potential for chemical and biological sensing. Green tea, or more specifically its main antioxidant component, epigallocatechin gallate (EGCG), has been found to disperse SWNTs in water. However, the chemical sensitivity of this SWNT/green tea (SWNT/EGCG) composite remained unexplored. With EGCG present, this SWNT composite should have strong antioxidant properties and thus respond to reactive oxygen species (ROS). Here we report on fabrication and characterization of SWNT/EGCG thin films and the measurement of their relative conductance as a function of H2O2 concentrations. We further investigated the sensing mechanism by Fourier-transform infrared (FTIR) spectroscopy and field-effect transistor measurements (FET). We propose here that the response to H2O2 arises from the oxidation of EGCG in the composite. These findings suggest that SWNT/green tea composite has a great potential for developing simple resistivity-based sensors. PMID:21043457

Chen, Yanan; Lee, Yang Doo; Vedala, Harindra; Allen, Brett L.; Star, Alexander

2010-01-01

256

Chemical compositions of soluble aerosols around the last termination in the NEEM (Greenland) ice core  

NASA Astrophysics Data System (ADS)

The polar ice cores provide us with reconstruction of past atmospheric aerosols. Atmospheric aerosols such as dust and sea salt in both Arctic and Antarctic ice cores are well discussed by using the proxy of ion concentration/flux. Recently, studies on the chemical compositions of soluble aerosols in the ice cores have been carried out. The chemical compositions and transition of soluble aerosols in the Dome Fuji (Antarctica) has been revealed, however, there are few studies on those of soluble aerosols in Greenland ice cores. Using ice sublimation method #1, we analyzed the chemical compositions of soluble aerosols around the last termination in the NEEM (Greenland) ice core. A total of 43 samples were distributed from NEEM ice core section from 1280 to 1580 m. Soluble aerosols were extracted from the samples by sublimation system. Constituent elements and diameter of each non-volatile particle were measured by scanning electron micro scope (SEM) and energy dispersive X-ray spectroscopy (EDS). By using a method in our recent paper #2, we assumed that particles containing Ca and S are calcium sulfate and particles containing Na and S are sodium sulfate. We divided around the last termination into 4 stages by focusing on the temperature; Holocene, Younger Dryas (YD), Bølling-Allerød (B-A) and Last Glacial Period (LGP), and compared the mass ratio of sulfate and chloride aerosols in each stage. During the cold stage in YD and LGP, calcium sulfate accounted large percentage of soluble aerosols. On the other hand, during the warm stage in Holocene and B-A, sodium sulfate accounted large percentage of soluble aerosols. These relationships between chemical composition and temperature are probably related to non sea salt (nss)-calcium ion concentration. We will discuss the relationship between nss-calcium ion concentration and chemical compositions of soluble aerosols in the presentation. References #1 Iizuka et al., J. Glaciol., 55(191), 58-64, 2009. #2 Iizuka, Y. et al. J. Geophys. Res. 117, D04308, 2012.

Oyabu, Ikumi; Iizuka, Yoshinori; Karlin, Torbjorn; Fukui, Manabu; Hondoh, Takeo; Hansson, Margareta

2013-04-01

257

Wintertime chemical composition of aerosols at a rural location in the Indo-Gangetic Plains  

NASA Astrophysics Data System (ADS)

Systematic measurements of mass concentration and chemical composition of aerosols have been carried out at Kharagpur in the Indo-Gangetic Plains during winter to identify the major sources over the region and to examine the changes in aerosol characteristics during haze events. Aerosol concentration is significantly large at the site, more than two-fold that of the National Ambient Air Quality Standards for residential areas in India. The main sources of aerosols over the region are anthropogenic activities and mineral dust. Species like SO42-, NO3-, NH4+, BC, Cl-, etc. are associated with anthropogenic sources, while Al, Fe, Ca, Na, Ti, Mn, etc. originate mainly from crustal sources. Though the site is only ˜100 km away from the Bay of Bengal, oceanic contribution is insignificant (˜2%), mainly due to prevailing north/northeasterly winds. A mean chemical composition evolved for the location shows that the aerosol system is composed of 17% mineral dust, 18% water-soluble components, 6% black carbon and 23% particulate organic matter along with a residual fraction of 36%. This residual fraction is attributed to organic aerosols of natural or secondary origin and water content of aerosols. An uncertainty of the order of 6-45% is involved in these estimations. Nevertheless, this mean chemical composition can act as a realistic input chemical model in the estimation of aerosol radiative forcing for this region. Analysis indicates that anthropogenic influence can be comparable to or exceeds natural aerosols at the location. The total aerosol mass concentration as well as that of anthropogenic species revealed enhancement on hazy days.

George, Susan K.; Nair, Prabha R.; Parameswaran, K.; Jacob, Salu

2011-08-01

258

Effects of chemical fuel composition on energy generation from thermopower waves.  

PubMed

Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ?2 V and an average peak specific power as high as 15 kW kg(-1) were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s(-1) and 157 mV, while they were 2 cm s(-1) and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H(+) and Na(+) ions, as well as the formation of fiber-like structures, because of benzene ? stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source. PMID:25319506

Yeo, Taehan; Hwang, Hayoung; Jeong, Dong-Cheol; Lee, Kang Yeol; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

2014-11-01

259

Effects of chemical fuel composition on energy generation from thermopower waves  

NASA Astrophysics Data System (ADS)

Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ?2 V and an average peak specific power as high as 15 kW kg?1 were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s?1 and 157 mV, while they were 2 cm s?1 and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H+ and Na+ ions, as well as the formation of fiber-like structures, because of benzene ? stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source.

Yeo, Taehan; Hwang, Hayoung; Jeong, Dong-Cheol; Lee, Kang Yeol; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

2014-11-01

260

Phylogenetic or environmental control on the organo-chemical composition of Sphagnum mosses?  

NASA Astrophysics Data System (ADS)

Decomposition of organic material is one of the key processes that determines the size of the soil-feedback to global warming, but it is also a process surrounded with one of the largest uncertainties, making understanding its mechanistic drivers of crucial importance. In organic soils decomposition is closely determined by the organo-chemical composition of the litter entering the soil. But what, in turn drives the organo-chemical composition? Is it an emergent feature of the environment the species producing the litter grow in, or is it an evolutionary trait that can be tracked through the species' phylogeny? We set out to answer this question for one of the most import peat-forming plants on earth: the genus Sphagnum. We sampled 18 Sphagnum species, about equally distributed over 6 sites spanning a wide range of environmental conditions: most species were collected at multiple sites. For all species we characterised the chemical composition, focussing on three functional chemistry groups: (i) mineral elements, (ii) carbohydrate polymers (iii) non-carbohydrate polymers (aromatic and aliphatic compounds) . For each group of compounds we used multivariate statistical techniques to derive the degree of variation explained by environment: (site, position within site) and phylogeny (sections within genus Sphagnum). We found that the variation in mineral element concentrations was mostly explained by environment, with the biggest differences in the concentrations of basic cat-ions calcium and magnesium. In contrast, the variation in carbohydrates was mostly explained by phylogeny, with clear associations between sections and monosaccharides. The monosaccharide rhamnose was associated with species from the Acutifolia section known for their poor degradability, whereas xylose and galactose were closely associated with degradable species from the Cuspidata section. The composition non-carbohydrate polymers took an intermediate position: both environment and phylogeny explained a significant part of the variation. We conclude that organo-chemical composition a function of both environment and phylogeny, but that the relative importance of these drivers depends on the type of compounds studied. Environment mainly drives the mineral element composition and a large part of the non-carbohydrate polymer composition, whereas phylogeny drives the variation in carbohydrate polymers. In our presentation we discuss the implications of our findings for carbon accumulation in peatlands and decomposition processes in general.

Limpens, Juul; Nilsson, Mats

2014-05-01

261

Some General Laws of Chemical Elements Composition Dynamics in the Hydrosphere  

NASA Astrophysics Data System (ADS)

The biophysical oceanic composition is a result of substance migration and transformation on river-sea and ocean- atmosphere boundaries. Chemical composition of oceanic water is a fundamental multi-dimensional constant for our planet. Detailed studies revealed three types of chemical element distribution in the ocean: 1) Conservative: concentration normalized to salinity is constant in space and time; 2) Nutrient-type: element concentration in the surface waters decreases due to the biosphere consumption; and 3) Litho-generative: complex character of distribution of elements, which enter the ocean with the river runoff and interred almost entirely in sediments (Fig. 1). The correlation between the chemical compositions of the river and oceanic water is high (r = 0.94). We conclude that biogeochemical features of each element are determined by the relationship between its average concentration in the ocean and the intensity of its migration through hydrosphere boundary zones. In Fig.1 we show intensities of global migration and average concentrations in the ocean in the coordinates lgC - lg ?, where C is an average element concentration and ? is its residual time in the ocean. Fig. 1 shows a relationship between three main geochemical parameters of the dissolved forms of chemical elements in the hydrosphere: 1) average concentration in the ocean, 2) average concentration in the river runoff and 3) the type of distribution in oceanic water. Using knowledge of two of these parameters, it allows gaining theoretical knowledge of the third. The System covers all chemical elements for the entire range of observed concentrations. It even allows to predict the values of the annual river transport of dissolved Be, C, N, Ge, Tl, Re, to refine such estimates for P, V, Zn, Br, I, and to determine the character of distribution in the ocean for Au and U. Furthermore, the System allowed to estimate natural (unaffected by anthropogenic influence) mean concentrations of elements in the river runoff and use them as ecological reference data. Finally, due to the long response time of the ocean, the mean concentrations of elements and patterns of their distribution in the ocean can be used to determine pre-technogenic concentrations of elements in the river runoff. An example of such studies for the Northern Eurasia Arctic Rivers will be presented at the conference. References Korzh 1974: J. de Recher. Atmos, 8, 653-660. Korzh 2008: J. Ecol., 15, 13-21. Korzh 2012: Water: Chem. & Ecol., No. 1, 56-62; Fig.1. The System of chemical elements distribution in the hydrosphere. Types of distribution in the ocean: 1) conservative; 2) nutrient-type; 3) litho-generative.

Korzh, V.

2012-12-01

262

Distribution and decline of endangered herbaceous heathland species in relation to the chemical composition of the soil  

Microsoft Academic Search

High atmospheric deposition of ammonium affects the physical and chemical status of the soil, increasing nitrogen availability, soil acidity and the mobilization of toxic metal ions. To investigate whether and how the decline of several herbaceous plant species in Dutch heathlands is associated with these processes, the chemical composition of the soil on which these species grow has been compared

A. L. F. M. Houdijk; P. J. M. Verbeek; H. F. G. VAN DIJK; J. G. M. Roelofs

1993-01-01

263

Soft magnetic composite particles of reduced iron coated with poly(p-xylylene) via chemical vapor deposition polymerization  

Microsoft Academic Search

Soft magnetic composite particles of reduced iron coated with ultrathin films of poly(p-xylylene) (PPX) were prepared via chemical vapor deposition (CVD) polymerization. The structure, morphology, magnetic properties, and chemical stability of PPX encapsulated reduced iron particles were studied. It can be confirmed from FTIR spectrum that the polymer covered outside the reduced iron particles is PPX. The thickness of PPX

Hongting Pu; Fengjing Jiang; Yongxing Wang; Biao Yan

2010-01-01

264

Rapid analysis of the chemical composition of agricultural fibers using near infrared spectroscopy and pyrolysis molecular beam mass spectrometry  

Microsoft Academic Search

The chemical composition of a variety of agricultural biomass samples was analyzed with near infrared spectroscopy and pyrolysis molecular beam mass spectroscopy. These samples were selected from a wide array of agricultural residue samples and included residues that had been subjected to a variety of different treatments including solvent extractions and chemical modifications. This analysis showed that both spectroscopic tools,

Stephen S. Kelley; Roger M. Rowell; Mark Davisb; Cheryl K. Jurich; Rebecca Ibachb

2004-01-01

265

Monovarietal extra virgin olive oils. Correlation between thermal properties and chemical composition: heating thermograms.  

PubMed

Extra virgin olive oils from drupes of three Sicilian varieties (Biancolilla, Cerasuola, and Nocellara del Belice) collected at three different harvesting periods were analyzed upon heating by means of DSC, and thermal properties were related to the chemical composition of the samples. All thermograms exhibited multiple transitions with a minor exothermic peak, followed by a major endothermic event. Cerasuola samples showed higher overall enthalpy and narrower range of transition at all harvesting periods, as compared to the other oils. A more ordered crystal structure originating from a more uniform chemical composition, with higher triolein content, in Cerasuola may be hypothesized. At different harvesting periods, thermal transitions started at lower temperatures and developed over a narrower range in all cultivars, probably due to the insertion of molecules derived from triacylglycerol lysis (diacylglycerols and free fatty acids) and lipid oxidation products into the triacylglycerol crystal lattice. All heating thermograms were deconvoluted into one exothermic and five endothermic constituent peaks, and the effect of chemical components on thermal properties of the peaks was evaluated. DSC application upon heating appears to be very promising in discriminating among oil samples from olives of different cultivars and/or harvesting periods. PMID:18167077

Chiavaro, Emma; Vittadini, Elena; Rodriguez-Estrada, Maria Teresa; Cerretani, Lorenzo; Bendini, Alessandra

2008-01-23

266

Aerosol chemical composition in cloud events by high resolution time-of-flight aerosol mass spectrometry.  

PubMed

This study presents results of direct observations of aerosol chemical composition in clouds. A high-resolution time-of-flight aerosol mass spectrometer was used to make measurements of cloud interstitial particles (INT) and mixed cloud interstitial and droplet residual particles (TOT). The differences between these two are the cloud droplet residuals (RES). Positive matrix factorization analysis of high-resolution mass spectral data sets and theoretical calculations were performed to yield distributions of chemical composition of the INT and RES particles. We observed that less oxidized hydrocarbon-like organic aerosols (HOA) were mainly distributed into the INT particles, whereas more oxidized low-volatile oxygenated OA (LVOOA) mainly in the RES particles. Nitrates existed as organic nitrate and in chemical form of NH(4)NO(3). Organic nitrates accounted for 45% of total nitrates in the INT particles, in clear contrast to 26% in the RES particles. Meanwhile, sulfates coexist in forms of acidic NH(4)HSO(4) and neutralized (NH(4))(2)SO(4). Acidic sulfate made up 64.8% of total sulfates in the INT particles, much higher than 10.7% in the RES particles. The results indicate a possible joint effect of activation ability of aerosol particles, cloud processing, and particle size effects on cloud formation. PMID:23419193

Hao, Liqing; Romakkaniemi, Sami; Kortelainen, Aki; Jaatinen, Antti; Portin, Harri; Miettinen, Pasi; Komppula, Mika; Leskinen, Ari; Virtanen, Annele; Smith, James N; Sueper, Donna; Worsnop, Douglas R; Lehtinen, Kari E J; Laaksonen, Ari

2013-03-19

267

Chemical composition of odorous secretions in the Tasmanian short-beaked echidna (Tachyglossus aculeatus setosus).  

PubMed

The short-beaked echidna is believed to use olfactory cues from a cloacal scent gland to attract and locate mates during the breeding season. We investigated the chemical composition of echidna secretions, including cloacal swabs and solid, "waxy" exudates from the cloaca and spurs. Scent samples from 37 individuals were collected over a 1-year period and analyzed using a range of different analytical techniques. A total of 186 compounds were identified, including volatile carboxylic acids, aldehydes, ketones, fatty acids, methyl esters, ethyl esters, terpenes, nitrogen- and sulphur-containing compounds, alcohols, and aromatics. Long chain and very long chain monounsaturated fatty acids, sterols, and sterol esters were identified as the major constituents of solid exudates, some of which have not previously been described from any animal skin gland. There was a high degree of composition overlap between male and female cloaca swabs; however, there is significant variation, which could mediate echidna mating behavior. Many of the volatile and nonvolatile chemicals detected are used for communication in other species, suggesting that chemical signals have important and diverse functions in echidna social interactions. PMID:22871649

Harris, Rachel L; Davies, Noel W; Nicol, Stewart C

2012-11-01

268

Aging of Secondary Organic Aerosol from ?-Pinene: Changes in Chemical Composition, Density and Morphology  

NASA Astrophysics Data System (ADS)

Biogenic volatile organic compounds (VOC) are emitted in large quantities into the atmosphere. These VOC, which includes ?-pinene, can react to produce secondary organic aerosols (SOA), which contribute to a substantial fraction of ambient organic aerosols and are known to adversely affect visibility, climate and health. Despite this, the current knowledge regarding the SOA composition, their physical properties and the chemical aging processes they undergo in the atmosphere is limited. In this study, chemical aging of SOA generated from the photooxidation of ?-pinene was investigated in the York University smog chamber. The formation and aging of both gas and particle phase products were analyzed using an atmospheric pressure chemical ionization triple quadrupole mass spectrometer. The density of secondary organic matter was also simultaneously measured over the course of the aging experiments, allowing us to improve our understanding in changes in particle composition that may occur. In addition, particle phase and shape was investigated for generated particles from ?-pinene oxidation by scanning electron microscope (SEM). Results of this work, including particle density and morphology will be presented as well as comparisons of gas and particle phase products time profiles during aging.

Sarrafzadeh, M.; Hastie, D. R.

2013-12-01

269

Chemical composition, nutritional and antioxidant properties of the red edible seaweed Porphyra columbina.  

PubMed

Proximate composition, fatty acids and amino acid profiles and nutritional (chemical score, protein digestibility, PDCAAS and mineral dialyzability) and antioxidant properties (TEAC, DPPH and power reduction) from Porphyra columbina were evaluated. Total dietary fiber (48.02?±?1.13?g/100?g dry weight) and protein (24.61?±?0.21?g/100?g dry weight) were the two most abundant components in this seaweed. The main saturated and unsaturated fatty acids were C16:0 and C20:5 (n-3), respectively. The limiting amino acid was tryptophan with a chemical score of 57%. Protein digestibility was 74.33?±?3.0%. Porphyra columbina has high mineral content with good Na/K relationship and medium value of potential mineral accessibility (P, Ca and Zn dializability: 18.75?±?0.01, 17.62?±?0.16 and 16.70?±?0.44, respectively). The highest antioxidant properties were obtained with an acetone/water extraction system. This work provides important information about chemical composition and nutraceutical new properties of P. columbina. PMID:24219228

Cian, Raúl E; Fajardo, María A; Alaiz, Manuel; Vioque, Javier; González, Rolando J; Drago, Silvina R

2014-05-01

270

Crystal Structure and Chemical Composition of a Presolar Silicate from the Queen Elizabeth Range 99177 Meteorite  

NASA Technical Reports Server (NTRS)

Mineral characterization of presolar silicate grains, the most abundant stardust phase, has provided valuable information about the formation conditions in circumstellar environments and in super-nova (SN) outflows. Spectroscopic observations of dust around evolved stars suggest a majority of amor-phous, Mg-rich olivine grains, but crystalline silicates, most of which are pyroxene, have also been observed [1]. The chemical compositions of hundreds of presolar silicates have been determined by Auger spectroscopy and reveal high Fe contents and nonstoichiometric compositions intermediate to olivine and pyroxene [2-6]. The unexpectedly high Fe contents can partly be attributed to secondary alteration on the meteorite parent bodies, as some grains have Fe isotopic anomalies from their parent stellar source [7]. Only about 35 presolar silicates have been studied for their mineral structures and chemical compositions by transmission electron microscopy (TEM). These grains display a wide range of compositions and structures, including crystalline forsterite, crystalline pyroxene, nanocrystalline grains, and a majority of amorphous nonstoichiometric grains. Most of these grains were identified in the primitive Acfer 094 meteorite. Presolar silicates from this meteorite show a wide range of Fe-contents, suggestive of secondary processing on the meteorite parent body. The CR chondrite QUE 99177 has not suffered as much alteration [8] and displays the highest presolar silicate abundance to date among carbonaceous chondrites [3, 6]. However, no mineralogical studies of presolar silicates from this meteorite have been performed. Here we examine the mineralogy of a presolar silicate from QUE 99177.

Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S.

2013-01-01

271

Chemical composition and in vitro anti-inflammatory activity of apple phenolic extracts and of their sub-fractions.  

PubMed

Apple extract powders from three different manufacturers were investigated for their anti-inflammatory activity, their total phenolic content, and their chemical composition. The samples represented two production batches for two products and a single batch of a third. The samples showed similar, but clearly different, anti-inflammatory activities, and had substantially different total phenolic contents, and different chemical compositions. Differences in chemical composition for batches of the same product were significant, although not as great as differences between products. The samples were fractionated into chemical classes. The most active fractions were those that contained epicatechin, catechin with phloridzin and quercetin glycosides, or those that contained procyanidin polymers. It was not possible to link activity to the presence of individual components or combinations of these. If fruit extracts are to be reliably linked to validated health benefits, then the source materials, the extraction processes, and the final composition of such products need to be more clearly defined than at present. PMID:19391030

Lauren, Denis R; Smith, Wendy A; Adaim, Aselle; Cooney, Janine M; Wibisono, Reginald; Jensen, Dwayne J; Zhang, Jingli; Skinner, Margot A

2009-01-01

272

Inhable particulate matter from lime industries: Chemical composition and deposition in human respiratory tract  

NASA Astrophysics Data System (ADS)

Air pollution caused by the lime production industry has become a serious problem with potential effects to human health, especially in developing countries. Colombo is a city included in the Metropolitan Region of Curitiba (capital of Paraná State) in South Brazil. In Colombo city, a correlation has been shown between the lime production and the number of persons who need respiratory treatment in a local hospital, indicating that the lime industry can cause deleterious health effects in the exposed workers and population. This research was conducted to deal firstly with the characterization of the size distribution and chemical compositions of particles emitted from lime manufacturing and subsequently to assess the deposition rate of inhaled dolomitic lime aerosol particles in the human respiratory tract. The elemental chemical composition and particle size of individual atmospheric particles was quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis. Information concerning the bulk composition is provided by energy-dispersive X-ray detection. The majority of the respirable particulate matter identified was composed of aluminosilicates, Ca-Mg oxides, carbon-rich particles, mixtures of organic particles and Ca-Mg carbonates, soot and biogenic particles. In view of the chemical composition and size distribution of the aerosol particles, local deposition efficiencies in the human respiratory system were calculated, revealing the deposition of CaO·MgO at extrathoracic, tracheobronchial and pulmonary levels. The results of this study offer evidence to the threat of the fine and coarse particles emitted from dolomite lime manufacturing, allowing policy-makers to better focus their mitigation strategies in an effective way, as well as to the dolomite producers for the purpose of designing and/or implementing improved emission controls.

Godoi, Ricardo H. M.; Braga, Darci M.; Makarovska, Yaroslava; Alfoldy, Balint; Carvalho Filho, Marco A. S.; Van Grieken, Réne; Godoi, Ana Flavia L.

273

Bullets fragments identification by comparison of their chemical composition obtained using instrumental neutron activation analysis.  

PubMed

Bullets found in crime scenes are usually compared by examination of the rifling impressions produced in the barrel of the questioned firearm. When, however, a bullet is fragmented or highly deformed, the comparison of rifling micro striations cannot be performed, and the only way two compare two or more bullets is by a match of their chemical analysis. In spite of the limits of the chemical analysis methods, due to the frequent compositional lead variability of ammunition boxes, the technique still keeps its full value, both as trial element, and as an aid in the investigations. A case is reported in the present paper, in which some crushed and deformed bullets, recovered from a murder victim body, have been analyzed by Instrumental Neutron Activation Analysis. The analysis allowed the assignation of the bullets to one of the ammunitions lots owned by one of the murder suspect. PMID:20591591

Sedda, Antioco Franco; Rossi, Gabriele

2011-03-20

274

Chemically bonded ceramic matrix composites: Densification and conversion to diffusion bonding  

SciTech Connect

Chemically bonded ceramics appear to be a promising alternative route for near-net shape fabrication of multi-phase ceramic matrix composites (CMC`s). The hydraulic (and refractory) properties of fine mono-calcium aluminate (CaAl{sub 2}O{sub 4}) powders were used as the chemically bonding matrix phase, while calcia stabilized zirconia powders were the second phase material. Samples containing up to 70 wt% (55 vol%) zirconia have been successfully compacted and sintered. Various processing techniques were evaluated. Processing was optimized based on material properties, dilatometry and simultaneous thermal analysis (DTA/TGA). The physical characteristics of this novel CMC were characterized by hardness, density, and fracture toughness testing. Microstructures were evaluated by SEM and phase identification was verified using XRD.

Johnson, B.R.; Guelguen, M.A.; Kriven, W.M. [Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering

1995-10-01

275

Process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition  

DOEpatents

A chemical vapor deposition (CVD) process for preparing fiber-reinforced ceramic composites. A specially designed apparatus provides a steep thermal gradient across the thickness of a fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.

Lackey, Jr., Walter J. (Oak Ridge, TN); Caputo, Anthony J. (Knoxville, TN)

1986-01-01

276

Chemical composition of shale oil. 1; Dependence on oil shale origin  

SciTech Connect

This paper reports on shale oils obtained by nitrogen retorting of North Carolina, Cleveland, Ohio, Colorado, Rundle, Stuart, and Condor oil shales that have been chemically characterized by g.c.-m.s. techniques. After species identification, chemical compositions of the shale oils have been related to the geological origins of the parent shales. Based on the characteristics observed in the chromatograms, eight semi-quantitative parameters have been used to describe the chromatograms. Six of these parameters describe the chromatograms. Six of these parameters describe the relative abundance and distribution of straight chain alkanes and alkenes in the chromatograms. The other two parameters represent the abundance, relative to the total amount of volatiles in the oil, of alkylbenzenes and alkylphenols.

Kesavan, S.; Lee, S. (Dept. of Chemical Engineering, The Univ. of Akron, Akron, OH (US)); Polasky, M.E. (Dow Chemical Co., Freeport, TX (US))

1991-01-01

277

Recent Progress of Propolis for Its Biological and Chemical Compositions and Its Botanical Origin  

PubMed Central

Propolis is the generic name given to the product obtained from resinous substances, which is gummy and balsamic and which is collected by bees from flowers, buds, and exudates of plants. It is a popular folk medicine possessing a broad spectrum of biological activities. These biological properties are related to its chemical composition and more specifically to the phenolic compounds that vary in their structure and concentration depending on the region of production, availability of sources to collect plant resins, genetic variability of the queen bee, the technique used for production, and the season in which propolis is produced. Many scientific articles are published every year in different international journal, and several groups of researchers have focused their attention on the chemical compounds and biological activity of propolis. This paper presents a review on the publications on propolis and patents of applications and biological constituents of propolis. PMID:23737843

Toreti, Viviane Cristina; Sato, Helia Harumi; Pastore, Glaucia Maria; Park, Yong Kun

2013-01-01

278

Aspen defense chemicals influence midgut bacterial community composition of gypsy moth.  

PubMed

Microbial symbionts are becoming increasingly recognized as mediators of many aspects of plant - herbivore interactions. However, the influence of plant chemical defenses on gut associates of insect herbivores is less well understood. We used gypsy moth (Lymantria dispar L.), and differing trembling aspen (Populus tremuloides Michx.) genotypes that vary in chemical defenses, to assess the influence of foliar chemistry on bacterial communities of larval midguts. We evaluated the bacterial community composition of foliage, and of midguts of larvae feeding on those leaves, using next-generation high-throughput sequencing. Plant defense chemicals did not influence the composition of foliar communities. In contrast, both phenolic glycosides and condensed tannins affected the bacterial consortia of gypsy moth midguts. The two most abundant operational taxonomic units were classified as Ralstonia and Acinetobacter. The relative abundance of Ralstonia was higher in midguts than in foliage when phenolic glycoside concentrations were low, but lower in midguts when phenolic glycosides were high. In contrast, the relative abundance of Ralstonia was lower in midguts than in foliage when condensed tannin concentrations were low, but higher in midguts when condensed tannins were high. Acinetobacter showed a different relationship with host chemistry, being relatively more abundant in midguts than with foliage when condensed tannin concentrations were low, but lower in midguts when condensed tannins were high. Acinetobacter tended to have a greater relative abundance in midguts of insects feeding on genotypes with high phenolic glycoside concentrations. These results show that plant defense chemicals influence herbivore midgut communities, which may in turn influence host utilization. PMID:25475786

Mason, Charles J; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

2015-01-01

279

Chemical composition, nutritional value, and antioxidant activities of eight mulberry cultivars from China  

PubMed Central

Background: Mulberry (Morus, Moraceae) is widely distributed in the temperate, subtropical, or tropical regions of the world, while there are no conclusive reports on the chemical composition, nutritional value, and antioxidant properties of mulberry cultivars from China. Objective: To investigate chemical properties and to determine proximate nutritive compounds of the eight mulberry cultivars. Materials and Methods: Chemical properties (including moisture, ash, total dry matter, total soluble solids, pH, and total titratable acidity) of the eight mulberry cultivars were investigated. Proximate nutritive compounds (including crude protein, crude fat, mineral elements, total anthocyanins, total polyphenols, total flavonoids, and total sugars) were also determined. Results: The results indicated that the moisture contents were 70.0-87.4%, the crude protein contents 1.62-5.54%, and the crude fat contents from 1.23-2.23%. The major fatty acids in mulberry fruits were linoleic acid (C18:2) and palmitic acid (C16:0), 26.40-74.77% and 9.29-22.26%, respectively. Mulberry fruit is also a good source of minerals and the potassium content (521.37-1718.60 mg/100g DW) is especially higher than that of other elements. Compared with other species, the Morus atropurpurea Roxb. had relatively high total polyphenols content (189.67-246.00 mg GAE/100mg) and anthocyanins content (114.67-193.00 mg/100mg). There was a good linear correlation between antioxidant activity and total polyphenols content. Conclusion: Significant differences of the chemical composition, nutritional value, and antioxidant activities among the mulberry cultivars were observed, the Morus atropurpurea Roxb. showed considerable high nutritional value and antioxidant activity which could be developed for functional food that benefits human health. PMID:23060696

Liang, Linghong; Wu, Xiangyang; Zhu, Maomao; Zhao, Weiguo; Li, Fang; Zou, Ye; Yang, Liuqing

2012-01-01

280

Influence of a Passivated Nanodimensional Aluminum Powder on Physical and Chemical Characteristics of Combustion of Metal Compositions  

NASA Astrophysics Data System (ADS)

The influence of various nanodimensional metal powders on the linear combustion rate of metal compositions is analyzed. It is demonstrated that passivation of nanoaluminum with glycine not only provides its physical and chemical compatibility with other components of a high-energy material and its subsequent physical and chemical stability, but also does not influence the main integral combustion characteristic that opens possibilities for its application as a fuel in high-energy compositions.

Komarova, M. V.; Vorozhtsov, A. B.

2014-11-01

281

Composition and production rate of pharmaceutical and chemical waste from Xanthi General Hospital in Greece  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We studied pharmaceutical and chemical waste production in a Greek hospital. Black-Right-Pointing-Pointer Pharmaceutical waste comprised 3.9% w/w of total hazardous medical waste. Black-Right-Pointing-Pointer Unit production rate for total pharmaceutical waste was 12.4 {+-} 3.90 g/patient/d. Black-Right-Pointing-Pointer Chemical waste comprised 1.8% w/w of total hazardous medical waste. Black-Right-Pointing-Pointer Unit production rate for total chemical waste was 5.8 {+-} 2.2 g/patient/d. - Abstract: The objective of this work was to determine the composition and production rates of pharmaceutical and chemical waste produced by Xanthi General Hospital in Greece (XGH). This information is important to design and cost management systems for pharmaceutical and chemical waste, for safety and health considerations and for assessing environmental impact. A total of 233 kg pharmaceutical and 110 kg chemical waste was collected, manually separated and weighed over a period of five working weeks. The total production of pharmaceutical waste comprised 3.9% w/w of the total hazardous medical waste produced by the hospital. Total pharmaceutical waste was classified in three categories, vial waste comprising 51.1%, syringe waste with 11.4% and intravenous therapy (IV) waste with 37.5% w/w of the total. Vial pharmaceutical waste only was further classified in six major categories: antibiotics, digestive system drugs, analgesics, hormones, circulatory system drugs and 'other'. Production data below are presented as average (standard deviation in parenthesis). The unit production rates for total pharmaceutical waste for the hospital were 12.4 (3.90) g/patient/d and 24.6 (7.48) g/bed/d. The respective unit production rates were: (1) for vial waste 6.4 (1.6) g/patient/d and 13 (2.6) g/bed/d, (2) for syringe waste 1.4 (0.4) g/patient/d and 2.8 (0.8) g/bed/d and (3) for IV waste 4.6 (3.0) g/patient/d and 9.2 (5.9) g/bed/d. Total chemical waste was classified in four categories, chemical reagents comprising 18.2%, solvents with 52.3%, dyes and tracers with 18.2% and solid waste with 11.4% w/w of the total. The total production of chemical waste comprised 1.8% w/w of the total hazardous medical waste produced by the hospital. Thus, the sum of pharmaceutical and chemical waste was 5.7% w/w of the total hazardous medical waste produced by the hospital. The unit production rates for total chemical waste for the hospital were 5.8 (2.2) g/patient/d and 1.1 (0.4) g/exam/d. The respective unit production rates were: (1) for reagents 1.7 (2.4) g/patient/d and 0.3 (0.4) g/examination/d, (2) for solvents 248 (127) g/patient/d and 192 (101) g/examination/d, (3) for dyes and tracers 4.7 (1.4) g/patient/d and 2.5 (0.9) g/examination/d and (4) for solid waste 54 (28) g/patient/d and 42 (22) g/examination/d.

Voudrias, Evangelos, E-mail: voudrias@env.duth.gr [Department of Environmental Engineering, Democritus University of Thrace, GR-671 00 Xanthi (Greece); Goudakou, Lambrini; Kermenidou, Marianthi; Softa, Aikaterini [Department of Environmental Engineering, Democritus University of Thrace, GR-671 00 Xanthi (Greece)

2012-07-15

282

Aligned Carbon Nanotube/ Amorphous Carbon Composite Thin Films By Microwave Plasma Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Microwave plasma chemical vapor deposition (MPCVD) is used to produce ordered, aligned arrays of carbon nanotubes on Ti-6Al-4V alloy substrates that have been sputter coated with cobalt catalyst. The nanotube growth is carried out using a ammonia/acetylene plasma in a 2.45 GHz, 6 kW microwave plasma reactor at the University of Alabama at Birmingham. We explore several approaches to fill the space beween nanotubes with a matrix via plasma chemistries employing methane/hydrogen/nitrogen which deposit nanostructured carbon films. The composite thin films created by this method should be uniquely suited to coating curved or spherical surfaces with a wear resistant coating, as the nanotubes consistently grow normal to the metal substrate surface. Nanotube composite thin films are anlyzed by Raman spectroscopy and x-ray diffraction. Surface roughness and morphology will be investigated by AFM and SEM. Nanoindentation hardness and elastic modulus measurements on composite thin films will be presented.

Fries, Marc; Vohra, Yogesh

2001-03-01

283

Influence of the polymerization process on composite resistance to chemical degradation by food-simulating liquids.  

PubMed

This study determined the influence of curing lights and modes on composite resistance to chemical degradation by various food-simulating liquids. Two different types of curing light (Halogen [H]-Elipar Trilight, 3M-ESPE; LED [L]-Freelight, 3M-ESPE) and two curing modes (standard [S]; exponential [E) were evaluated in the study. Forty-five composite (Z100 [3M-ESPE]) specimens were made for each light-curing mode combination (HS, HE, LS and LE). The specimens were randomly divided into five groups of nine and exposed to the following food-simulating liquids (FSL) for one week at 37 degrees C: distilled water, 50% aqueous ethanol solution, heptane and citric acid. Specimens stored in air were used as control. After the one week conditioning period, hardness testing was conducted with a digital microhardness tester (load = 500 gf; dwell time = 15 seconds). Mean hardness (HK)/hardness deterioration (deltaHK) were subsequently computed and data was subjected to analysis using ANOVA/Scheffe's test (p < 0.05). The resistance of composite to chemical degradation by FSL was light/curing mode dependent. Significant differences in HK and deltaHK were observed among the four curing techniques after conditioning in some FSL and air. After conditioning in water and citric acid, specimens polymerized with HE underwent significantly more softening compared to specimens polymerized with HS, LS and LE. PMID:14653286

Yap, Adrian U J; Wattanapayungkul, P; Chung, S M

2003-01-01

284

Biomineralized porous composite scaffolds prepared by chemical synthesis for bone tissue regeneration.  

PubMed

Scaffold design is a key factor in the clinical success of bone tissue engineering grafts. To date, no existing single biomaterial used in bone repair and regeneration fulfils all the requirements for an ideal bone graft. In this study hydroxyapatite/polycaprolactone (HA/PCL) composite scaffolds were prepared by a wet chemical method at room temperature. The physico-chemical properties of the composite materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, while scaffold morphology was investigated by scanning electron microscopy (SEM) with energy-dispersive spectroscopy to validate the process used for synthesis. Finally, the response of bone marrow-derived human mesenchymal stem cells (hMSCs) in terms of cell proliferation and differentiation to the osteoblastic phenotype was evaluated using the Alamar blue assay, SEM and alkaline phosphatase activity. Microstructural analysis indicated that the HA particles were distributed homogeneously within the PCL matrix. The biological results revealed that the HA/PCL composite scaffolds are suitable for the proliferation and differentiation of MSCs in vitro, supporting osteogenesis after 15 days. All the results indicate that these scaffolds meet the requirements of materials for bone tissue engineering and could be used for many clinical applications in orthopaedic and maxillofacial surgery. PMID:20417736

Raucci, M G; D'Antò, V; Guarino, V; Sardella, E; Zeppetelli, S; Favia, P; Ambrosio, L

2010-10-01

285

Characterization of the chemical composition of polyisobutylene-based oil-soluble dispersants by fluorescence.  

PubMed

A novel methodology based on fluorescence quenching measurements is introduced to determine quantitatively the amine content of polyisobutylene succinimide (PIBSI) dispersants used as engine oil-additives. To this end, a series of five PIBSI dispersants were prepared by reacting 2 mol equiv of polyisobutylene succinic anhydride (PIBSA) with 1 mol equiv of hexamethylenediamine (HMDA), diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine to yield the corresponding b-PIBSI dispersants. After having demonstrated that the presence of hydrogen bonds between the polyamine linker and the succinimide carbonyls of the dispersants prevents the quantitative analysis of the (1)H NMR and FTIR spectra of the dispersants to determine their chemical composition, alternative procedures based on gel permeation chromatography (GPC) and fluorescence quenching were implemented to estimate the amine content of the b-PIBSI dispersants. Taking advantage of the doubling in size that occurs when 2 mol of PIBSA are reacted with 1 mol of HMDA, a combination of GPC and FTIR was employed to follow how the chemical composition and molecular weight distribution of the polymers produced evolved with the reaction of PIBSA and HMDA mixed at different molar ratios. These experiments provided the PIBSA-to-HMDA molar ratio yielding the largest b-PIBSI dispersants and this molar ratio was then selected to prepare the four other dispersants. Having prepared five b-PIBSI dispersants with well-defined secondary amine content, the fluorescence of the succinimide groups was found to decrease with increasing number of secondary amines present in the polyamine linker. This result suggests that fluorescence quenching provides a valid method to determine the chemical composition of b-PIBSI dispersants which is otherwise difficult to characterize by standard (1)H NMR and FTIR spectroscopies. PMID:24628080

Pirouz, Solmaz; Wang, Yulin; Chong, J Michael; Duhamel, Jean

2014-04-10

286

Chemical Separations  

NSDL National Science Digital Library

This site contains complete notes in a PowerPoint-like presentation for a chemical separations course. It covers a wide variety of topics, including distillation, extraction, gas chromatography, liquid chromatograpy, chromatography theory, instrumentation, electrophoresis, field flow fractionation, and affinity chromatography. It covers these topics thoroughly using a clear, consistent, and simple presentation style. Links to major topics like GC, LC, and electrophoresis provide specific information about the theory, instrumentation, and practice related to these techniques. The site also contains many annimations illustrating important separation processes.

287

Chemical Composition of Subway Particles in Seoul, Korea, Determined Using Quantitative Single Particle Analysis  

Microsoft Academic Search

\\u000a A novel single particle analytical technique, called low-Z particle electron probe X-ray microanalysis, was applied to characterize seasonal indoor aerosol samples collected at a subway\\u000a station in Seoul, Korea. Four major types of particles, based on their chemical compositions, are significantly encountered:\\u000a Fe-containing; soil-derived; carbonaceous; and secondary nitrate and\\/or sulfate particles. Fe-containing particles are present\\u000a in the greatest amounts, with

Hae-Jin Jung; Sunni Kang; Hye Kyeong Kim; Chul-Un Ro

288

Ion-Molecule Reactions and Chemical Composition of Emanated from Herculane Spa Geothermal Sources  

PubMed Central

The paper presents a chemical composition analysis of the gases emanated from geothermal sources in the Herculane Spa area (Romania). The upper homologues of methane have been identified in these gases. An ion-molecule reaction mechanism could be implicated in the formation of the upper homologues of methane. The CH4+ ions that appear under the action of radiation are the starting point of these reactions. The presence of hydrogen in the emanated gases may be also a result of these reactions. PMID:19325844

Cosma, Constantin; Suciu, Ioan; Jäntschi, Lorentz; Bolboac?, Sorana D.

2008-01-01

289

Relation of the Occurrence of Cotton Root Rot to the Chemical Composition of Soils.  

E-print Network

:~p$ne$$ 9 -FK~( Q9"y.a *e4*&; I * Relation of the occurrence of Cotton Root7*'. Rot to the Chemical Composition of Soils -- AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON, President Soils in which cotton root rot generally occurs.... It has been found in about 200 counties of Texas (16), including practically all of the State except the Panhandle and parts of the mountainous country near the New Mexico line. Cotton root rot affects not only cotton, but a large variety of other...

Fraps, G. S. (George Stronach); Fudge, J. F. (Joseph Franklin)

1935-01-01

290

LOAD TRANSFER AND MECHANICAL PROPERTIES OF CHEMICALLY DERIVED SINGLE LAYER GRAPHENE REINFORCEMENTS IN POLYMER COMPOSITES  

PubMed Central

We report load transfer and mechanical properties of chemically derived single layer graphene (SLG) as reinforcements in poly (dimethyl) siloxane (PDMS) composites. Mixing single layer graphene in polymers resulted in the marked decrease of the G’ or 2D band intensity due to doping and functionalization. A Raman G mode shift of 11.2 cm?1/% strain in compression and 4.2 cm?1/% strain in tension is reported. An increase in elastic modulus of PDMS by ~42%, toughness by ~39%, damping capability by ~673%, and strain energy density of ~43% by the addition of 1 wt. % SLG in PDMS is reported. PMID:23196792

Xu, Peng; Loomis, James; Panchapakesan, Balaji

2013-01-01

291

The purification procedure for human gastric juice FSA and its chemical composition.  

PubMed Central

A purification procedure for a gastric cancer-associated glycoprotein FSA is described. This substance was considered to be sulphated but is now found to derive its charge from carboxylic groups and has been renamed foetal sialoglycoprotein. The chemical composition is similar to blood group substances with differences which may reflect its origin from gastric cancer. The molecular size differs from that of the carcinoembryonic antigen. The calculation of the yield based on dry weight measurements is not possible until a radioimmunoassay technique becomes available and development of such an assay is now in progress in our laboratory. PMID:7460391

Häkkinen, I P

1980-01-01

292

Chemical composition and possible in vitro phytotoxic activity of Helichrsyum italicum (Roth) Don ssp. italicum.  

PubMed

The chemical composition of the essential oil of Helichrysum italicum (Roth) Don ssp. italicum, collected in the National Park of Cilento and Diano Valley, Southern Italy, was studied by means of GC and GC/MS. Forty four compounds of 45 constituents were identified in the oil, mainly oxygenated sesquiterpenes. The essential oil was evaluated for its potential in vitro phytotoxic activity against germination and early radicle elongation of radish and garden cress. The radicle elongation of radish was significantly inhibited at the highest doses tested, while germination of both seeds was not affected. PMID:21904272

Mancini, Emilia; De Martino, Laura; Marandino, Aurelio; Scognamiglio, Maria Rosa; De Feo, Vincenzo

2011-01-01

293

Influence of electropolishing and anodic oxidation on morphology, chemical composition and corrosion resistance of niobium.  

PubMed

The work presents results of the studies performed on electropolishing of pure niobium in a bath that contained: sulphuric acid, hydrofluoric acid, ethylene glycol and acetanilide. After the electropolishing, the specimens were subjected to anodic passivation in a 1moldm(-3) phosphoric acid solution at various voltages. The surface morphology, thickness, roughness and chemical composition of the resulting oxide layers were analysed. Thusly prepared niobium samples were additionally investigated in terms of their corrosion resistance in Ringer's solution. The electropolished niobium surface was determined to be smooth and lustrous. The anodisation led to the growth of barrier-like oxide layers, which were enriched in phosphorus species. PMID:25063150

Sowa, Maciej; Gre?, Katarzyna; Kukharenko, Andrey I; Korotin, Danila M; Michalska, Joanna; Szyk-Warszy?ska, Lilianna; Mosia?ek, Micha?; Zak, Jerzy; Pamu?a, El?bieta; Kurmaev, Ernst Z; Cholakh, Seif O; Simka, Wojciech

2014-09-01

294

Chemical Composition Dependent Elastic Strain in AlGaN Epilayers  

NASA Astrophysics Data System (ADS)

Systematic investigations are performed on a set of AlxGa1?xN/GaN heterostructures grown by metalorganic chemical vapor deposition on sapphire (0001). The Al composition x is determined by Rutherford backscattering. By using high resolution x-ray diffraction and the channeling scan around an off-normal <12¯13> axis in {101¯0} plane of the AlGaN layer, the tetragonal distortion eT caused by the elastic strain in the epilayer is determined. The results show that eT in the high-quality AlGaN layers is dramatically influenced by the Al content.

Wang, Huan; Yao, Shu-De

2014-10-01

295

Deuterium quadrupole echo NMR spectroscopy. I. Effects of chemical exchange during single and composite pulses  

NASA Astrophysics Data System (ADS)

The effects of chemical exchange during rf pulses on deuterium quadrupole echo spectra have been evaluated numerically for single pulses as well as for Levitt-Suter-Emst composite pulses. In principle, the inclusion of exchange effects during pulses of finite length requires lengthy calculations of the evolution of the full density matrix. Fortunately, exchanging lineshapes can be simulated accurately using only the smaller single-quantum transition subset of spin-density-matrix elements provided that the lengths of the pulse-echo intervals are properly adjusted.

Barbara, Thomas M.; Greenfield, Michael S.; Vold, Robert L.; Vold, Regitze R.

296

The biological activities and chemical composition of Pereskia species (Cactaceae)--a review.  

PubMed

The exploration of nature as a source of sustainable, novel bioactive substances continues to grow as natural products play a significant role in the search for new therapeutic and agricultural agents. In this context, plants of the genus Pereskia (Cactaceae) have been studied for their biological activities, and are evolving as an interesting subject in the search for new, bioactive compounds. These species are commonly used as human foodstuffs and in traditional medicine to treat a variety of diseases. This review focuses on the bioactivity and chemical composition of the genus Pereskia, and aims to stimulate further studies on the chemistry and biological potential of the genus. PMID:24862084

Pinto, Nícolas de Castro Campos; Scio, Elita

2014-09-01

297

Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite  

Microsoft Academic Search

Size-resolved aerosol mass and chemical composition were measured during the Pittsburgh Air Quality Study. Daily samples were collected for 12 months from July 2001 to June 2002. Micro-orifice uniform deposit impactors (MOUDIs) were used to collect aerosol samples of fine particulate matter smaller than 10?m. Measurements of PM0.056, PM0.10, PM0.18, PM0.32, PM0.56, PM1.0, PM1.8 and PM2.5 with the MOUDI are

Juan C. Cabada; Sarah Rees; Satoshi Takahama; Andrey Khlystov; Spyros N. Pandis; Cliff I. Davidson; Allen L. Robinson

2004-01-01

298

The preparation and economics of silicon carbide matrix composites by chemical vapor infiltration  

SciTech Connect

This paper describes a number of processing techniques that are currently in use for the development and production of continuous fiber reinforced ceramic composite materials. The limited number of available processing routes are compared with respect to the resulting material properties. As it appears the Chemical Vapor Infiltration technique is one of the most extensively developed methods. During the last decade, at least five different modifications of the isobaric isothermal CVI principle have been developed; each route having its own benefits. CVI techniques have now been developed to the extent that industrial commercialization is being realized. Projected cost aspects of the various CVI manufacturing techniques have been examined and compared.

Roman, Y.G. [Centre for Technical Ceramics-TNO, Eindhoven (Netherlands); Stinton, D.P. [Oak Ridge National Lab., TN (United States)

1995-10-01

299

Heparins: process-related physico-chemical and compositional characteristics, fingerprints and impurities.  

PubMed

During the past 25 years, heparin extraction and purification processes have changed. The results of these changes are reflected by the continuous increase in potency of the International Standard for heparin. This increase is due not only to a higher purity, but also to a number of changes in the physico-chemical characteristics of heparin. For long time, all these changes have been disregarded as non-critical by regulatory authorities. Heparin marketing authorisation was reviewed only two years ago and Pharmacopoeia monographs were reviewed just for the addition of new tests, mainly aimed at tackling the oversulfated chondroitin sulfate (OSCS) crisis. Currently, heparin monographs are again under revision. Such changes, different for each manufacturer, have caused a further increase in the heterogeneity of individual batches of heparin. This review aims at showing that chemical, physical and biological characteristics of heparin (such as disaccharide composition, amount of low sulfated and high sulfated sequences, molecular weight profiles [MW], activities, structural artifacts, fingerprints and glycosaminoglycans impurities) are all process-dependent and may significantly vary when different processes are used to minimise the content of dermatan sulfate. The wide heterogeneity of the physico-chemical characteristics of currently marketed heparin and the lack of suitable and shareable reference standards for the identification/quantification of process-related impurities caused, and are still causing, heated debates among scientific institutions, companies and authorities. PMID:19888518

Liverani, Lino; Mascellani, Giuseppe; Spelta, Franco

2009-11-01

300

CHEMICAL IMAGES OF LIQUIDS  

Microsoft Academic Search

Following the success of electronic noses in a variety of applications related to many areas such as industrial, medical,\\u000a environmental, spatial, etc. where the objective was to construct chemical images of volatile compounds including odors, here\\u000a we introduce another system able to perform chemical images of liquids of different origin, quality, and composition. In line\\u000a with mammalian senses such as

L. Lvova; P. Paolesse; C. Di Natale; E. Martinelli; E. Mazzone; A. Orsini

301

Thermodynamic Modeling of the Chemical Composition of Calcine at the Idaho Nuclear Technology and Engineering Center  

SciTech Connect

To send calcine produced at Idaho National Engineering and Environmental Laboratory to the Yucca Mountain Project for disposal, characterization information will be required. To sample calcine from its existing storage location would require extensive personnel exposure. Sufficient analyses of the chemical composition of the calcine would be extremely difficult and very expensive. In support of characterization development, the chemical composition of calcine from Bin 3 of Calcine Solid Storage Facility II was thermodynamic modeled. This calcine was produced in the Waste Calcination Facility during its second processing campaign, operating with indirect heating at 400 C and 0.744 bar (0.734 atm) during processing of aluminum high-level liquid waste (first cycle extraction raffinate from reprocessing aluminum-clad fuels) from tanks WM-180 and -182 from December 27, 1966 through August 26, 1967. The current modeling effort documents the input compositional data (liquid feed and calciner off-gas) for Batches 300 - 620 and a methodology for estimating the calcine chemical composition. The results, along with assumptions and limitations of the thermodynamic calculations, will serve as a basis for benchmarking subsequent calculations. This will be done by comparing the predictions against extensive analytical results that are currently being obtained on representative samples of the modeled calcine. A commercial free-energy minimization program and database, HSC 5.1, was used to perform the thermodynamic calculations. Currently available experimental data and process information on the calcine were used to make judgments about specific phases and compounds to include and eliminate in the thermodynamic calculations. Some off-gas species were eliminated based on kinetics restrictions evidenced by experimental data and other estimates, and some calcine components and off-gas compounds were eliminated as improbable species (unreliable thermodynamic data). The current Yucca Mountain Project level of concern is 0.1 wt % of individual cations in the waste package. Chemical composition of the individual calcine components was calculated down to 0.02 mol % and 0.09 wt % of metal components of the calcine. The results reproduce closely existing experimental information on calcine chemical and phase composition. This paper discusses specific conditions accepted for the final calculations. The major calcine components, exceeding 0.15 mol % and 0.65 wt %, are: amorphous Al2O3 (85.30 mol %, 81.20 wt %); amorphous NaNO3 (8.23 mol %, 6.53 wt %); dolomite – CaMg 0.9235 (CO3)1.9235 (1.66 mol %, 2.75 wt %); amorphous HgO (0.99 mol %, 2.00 wt %); CaSO4 (0.64 mol %, 0.82 wt %); amorphous KNO3 (0.63 mol %, 0.59 wt %); amorphous Al4B2O9 (0.54 mol %, 1.37 wt %); and amorphous Al18B4O33 (0.16 mol %, 1.57 wt %). Na is present 99.8 % as NaNO3, 99.9 % of K is present as KNO3, and 53 % NOx is NO2(g), showing that the kinetics limiting effects have been empirically accounted for in the modeling. Approximately 87 % of the mercury is in calcine.

C. M. Frazee; J. D. Christian

2004-02-01

302

CHEMICAL COMPOSITION AND PCT DATA FOR THE INITIAL SET OF HANFORD ENHANCED WASTE LOADING GLASSES  

SciTech Connect

In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test results for 20 simulated high level waste glasses fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation ranges of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. Two components of the study glasses, fluorine and silver, were not measured since each of these species would have required the use of an additional preparation method and their measured values were likely to be near or below analytical detection limits. Some of the glasses were difficult to prepare for chemical analysis. A sodium peroxide fusion dissolution method was successful in completely dissolving the glasses. Components present in the glasses in minor concentrations can be difficult to measure using this dissolution method due to dilution requirements. The use of a lithium metaborate preparation method for the minor components (planned for use since it is typically successful in digesting Defense Waste Processing Facility HLW glasses) resulted in an unacceptable amount of undissolved solids remaining in the sample solutions. An acid dissolution method was used instead, which provided more thorough dissolution of the glasses, although a small amount of undissolved material remained for some of the study glasses. The undissolved material was analyzed to determine those components of the glasses that did not fully dissolve. These components (e.g., calcium and chromium) were present in sufficient quantities to be reported from the measurements resulting from the sodium peroxide fusion preparation method, which did not leave undissolved material. Overall, the analyses resulted in sums of oxides that ranged from about 98 to 101.5 wt % for the study glasses, indicating excellent recovery of all the components in the chemical composition analyses. Comparisons of the targeted and measured chemical compositions indicated that, in general, the measured values for the glasses met the targeted concentrations. Exceptions were Cr{sub 2}O{sub 3}, MgO, and P{sub 2}O{sub 5}. The measured values for Cr{sub 2}O{sub 3} were somewhat low when compared to the targeted values for all of the study glasses targeting Cr{sub 2}O{sub 3} concentrations above 0.5 wt %. Many of the measured MgO and P{sub 2}O{sub 5} values were below the targeted values for those glasses that contained these components. Two of the study glasses exhibited differences from the targeted compositions that may indicate a batching error. Glasses EWG-HAI-Centroid-2 and EWG-OL-1672 had measured values for Al{sub 2}O{sub 3} and SiO{sub 2} that were lower than the targeted values, and measured values for B{sub 2}O{sub 3} that were higher than the targeted values. Glass EWG-HAI-Centroid-2 also had a measured value for Fe{sub 2}O{sub 3} that was lower than the targeted value. A review of the PCT data, including standards and blanks, revealed no issues with the performance of the tests. The PCT results were normalized to both the targeted and measured compositions of the study glasses. Comparisons of the normalized PCT results for both the quenched and Canister Centerline Cooled versions of the study glasses are made with the Environmental Assessment benchmark glass for reference.

Fox, K.; Edwards, T.

2014-06-02

303

A Methodology for the Prediction of the Chemical Composition of Secondary Organic Aerosol  

NASA Astrophysics Data System (ADS)

Atmospheric aerosols have been identified by the Intergovernmental Panel on Climate Change in their recent reports (IPCC, 2007) as a key influence on climate change, but as also an influence about which we have minimal understanding. Atmospheric aerosols can contain a wide range of components but most are believed to be mainly composed of an inorganic part, an organic part and associated water. The inorganic component is relatively well understood and is composed of a limited number of ionic species. However, the organic component is much more complex as any of the thousands of organic compounds found in the atmosphere can potentially condense into the aerosol. A major contributor to the organic aerosol is believed to be from chemicals formed by atmospheric processes. Volatile organic compounds (VOC's) from both anthropogenic and biogenic sources (primary emissions), undergo progressive oxidation in the atmosphere and the products of these atmospheric reactions may contribute to the formation of secondary organic aerosol (SOA) particles. The oxidation process leads to increased functionalization of the VOC with a resulting increase in polarity and decrease in volatility. The less volatile components in this mixture may condense to form SOA particles by nucleation or by condensation onto particles (such as involatile primary emissions, or polymerised water soluble material) already present in the atmosphere. There is much speculation about the composition of SOA particles as complete analyses are not available. One approach is to model the formation of SOA using an explicit atmospheric chemistry scheme coupled to a condensation/absorption model. We will report on the use the Master Chemical Mechanism (MCM:- see http://mcm.leeds.ac.uk/MCM/) with a modified version of the Pankow absorption model to predict the chemical composition of SOA particles formed under a range of conditions. The MCM provided the atmospheric abundances of 3700 non-radical atmospheric chemical species in a trajectory model of a heavily polluted air parcel that arrived at Writtle (Essex) in the south of England at 18:00 on August 6th 2003 during the TORCH campaign. A similar set of abundances were simulated for an air-parcel arriving on August 12th with high concentrations of VOC's from biological sources. These two sets of atmospheric concentrations formed the inputs for the calculation of the chemical composition of anthropogenically dominated and biogenically dominated SOA respectively. The condensation of the oxidised VOC's were modelled using the following methodology:- 1) The model used was a modified version of the Pankow absorption model. 2) Estimated vapour pressures were used for all components and liquid phase ideality was assumed. 3) It was assumed that water condensed into the SOA alongside the organic components. 4) As liquid phase water is expected to be present the acid anhydrides predicted to be present in the atmosphere are expected to hydrolyse to their corresponding acids. 5) The presence of an involatile core onto which the organics can condense is assumed. Formation of SOA by condensation was modelled for both the anthropogenic and biogenic case over a range of temperatures, relative humidity and target mass (=core mass+SOA mass). This provided a range of SOA masses- particularly for the anthropogenic case where it was clear that the chemical composition of the SOA was strongly affected by the mass of SOA predicted. The results showed that anthropogenic SOA contained significant dicarboxylic acids derived from the hydrolysis of cyclic anhydrides while the biogenic SOA contained pinic acid (another dicarboxylic acid) and a range of multifunctional compounds dominated by hydroxyl and hydroperoxide groups.

Barley, M.; Topping, D.; McFiggans, G.; Jenkin, M.

2009-04-01

304

Chemical composition and binary mixture of human urinary stones using FT-Raman spectroscopy method  

NASA Astrophysics Data System (ADS)

In the present study the human urinary stones were observed in their different chemical compositions of calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate, struvite (magnesium ammonium phosphate), uric acid, cystine, oxammite (ammonium oxalate monohydrate), natroxalate (sodium oxalate), glushinkite (magnesium oxalate dihydrate) and moolooite (copper oxalate) were analyzed using Fourier Transform-Raman (FT-Raman) spectroscopy. For the quantitative analysis, various human urinary stone samples are used for ratios calculation of binary mixtures compositions such as COM/COD, HAP/COD, HAP/COD, Uric acid/COM, uric acid/COD and uric acid/HAP. The calibration curve is used for further analysis of binary mixture of human urinary stones. For the binary mixture calculation the various intensities bands at 1462 cm-1 (ICOM), 1473 cm-1 (ICOD), 961 cm-1 (IHAP) and 1282 cm-1 (IUA) were used.

Selvaraju, R.; Raja, A.; Thiruppathi, G.

2013-10-01

305

Photothermal method for in situ microanalysis of the chemical composition of coal samples  

DOEpatents

Successive minute regions along a scan path on a coal sample are individually analyzed, at a series of different depths if desired, to determine chemical composition including the locations, sizes and distributions of different maceral inclusions. A sequence of infrared light pulses of progressively changing wavelengths is directed into each minute region and a probe light beam is directed along the sample surface adjacent the region. Infrared wavelengths at which strong absorption occurs in the region are identified by detecting the resulting deflections of the probe beam caused by thermally induced index of refraction changes in the air or other medium adjacent the region. The detected peak absorption wavelengths are correlated with known characteristic peak absorption wavelengths of specific coal constituents to identify the composition of each such minute region of the sample. The method enables rapid, convenient and non-destructive analyses of coal specimens to facilitate mining, processing and utilization of coals. 2 figures.

Amer, N.M.

1983-10-25

306

Composition and chemical changes during storage of fish meal from Capelin (Mallotus villosus).  

PubMed

The stability of fish meal depends on processing and storage conditions, but habitat and seasonal variations in composition and naturally occurring anti- and pro-oxidants may be equally important. Capelin meal from four different seasons was examined by measuring chemical composition and monitoring lipid oxidation during storage. The results revealed that lipid content was high in the summer but low in the spring. It was further demonstrated that among naturally occurring antioxidants, astaxanthin was high during summer, whereas alpha-tocopherol was highest in spring. Mineral content varied, with a high copper content in the summer, whereas iron, selenium, and zinc were highest in the winter. Measurements on the stability of capelin meal indicated a decrease in peroxide values, oxygen uptake, and thiobarbituric acid reactive compounds with storage, whereas browning and CO concentration increased with time. Rancidity was highest in autumn, but free fatty acids were highest during spring and summer. PMID:15030213

Bragadóttir, Margrét; Pálmadóttir, Heida; Kristbergsson, Kristberg

2004-03-24

307

Effect of cottonseed oilcake inclusion on ostrich growth performance and meat chemical composition.  

PubMed

This study investigated the effect of replacing dietary soybean oilcake meal with increasing levels of cottonseed oilcake meal (CSOCM) on the growth performance and meat (Iliofibularis muscle) chemical composition of ostriches in order to decrease total feed costs. A total of 105 ostriches were divided into five feeding groups according to the CSOCM inclusion level in the whole diet: Control (0% CSOCM), 3%, 6%, 9% and 12% CSOCM (of the whole diet), and fed with experimental diets from 6 to 13 months of age. As a result of feeding CSOCM, the final live weight and the average daily gain significantly increased in the 12% CSOCM group. The proximate composition, cholesterol content, mineral and fatty acid profile of the meat remained unaffected. Thus CSOCM may be used as an alternative protein source to the more expensive soybean oilcake meal in ostrich nutrition. PMID:22998999

Dalle Zotte, A; Brand, T S; Hoffman, L C; Schoon, K; Cullere, M; Swart, R

2013-02-01

308

Chemical diversity of Ziziphora clinopodioides: composition of the essential oil of Z. clinopodioides from Tajikistan.  

PubMed

The chemical composition of the essential oils of Ziziphora clinopodioides Lam. from the aerial flowering parts, collected during two different years, were obtained by hydrodistillation and analyzed by gas chromatography - mass spectrometry. Forty-five components representing 100% and 94.7% of the total oil were identified. The main constituents of the essential oils were pulegone (72.8 and 35.0%), neomenthol (6.5 and 23.1%), menthone (6.2 and 13.3%), p-menth-3-en-8-ol (1.7 and 3.5%), piperitenone (2.6 and 1.1%) and piperitone (0.7 and 1.2%). A cluster analysis was carried out on the essential oil compositions of Z. clinopodioides. PMID:21615034

Sharopov, Farukh S; Setzer, William N

2011-05-01

309

Effect of the Chemical Composition on The Pyroplastic Deformation of Sanitaryware Porcelain Body  

NASA Astrophysics Data System (ADS)

Pyroplastic deformation is the bending of a ceramic specimen caused by gravity during heat treatment. It can be defined as the loss of shape of product during its firing. Pyroplastic deformation is related to properties of liquid phases formed during firing. Therefore, the effect of the chemical composition on the pyroplastic deformation of sanitaryware porcelain was investigated in this study. Systematical compositional arrangements were made according to different combinations of (SiO2/Al2O3) and (Na2O/K2O) ratios by using Seger formula approach. Pyroplastic deformation behaviour of compositions within a controlled firing regime was investigated by using fleximeter. The bodies were also prepared in a special form by slip casting method at laboratory scale in order to determine the pyroplastic deformation of the samples. The experimental results showed that a definite combination at SiO2/Al2O3 ratio of 5 and Na2O/K2O ratio of 4 give the lowest pyroplastic deformation in the porcelain body formulations. The pyroplastic deformation value of this composition was determined as 25 mm which is 44% lower than that of the standard composition (45 mm).

Ye?im Tunçel, Derya; Kerim Kara, Mustafa; Özel, Emel

2011-10-01

310

Chemical composition of growing pigs and its relationship with body tissue composition assessed by X-ray-computed tomography.  

PubMed

Ninety hybrid (mainly Large White × Landrace) pigs from 2 experimental replicates were used to study the potential use of computed tomography (CT) as a nondestructive technology for estimating the chemical body composition of growing pigs. Body tissue components (lean, fat, and bone) of 6 live pigs from each sex (boars, gilts, and barrows) were assessed by CT imaging before slaughter at approximately 30, 60, 90, 120, and 150 kg of BW. After slaughter, the empty body components were ground and frozen until analyzed for protein, lipid, ash, and moisture content. Several growth functions were evaluated and the allometric function (Y = aBW(b)), which was evaluated as log(10)chemical component weight = b(0) + b(1)log(10)BW, provided the best fit to the data. For each sex, the allometric coefficient (b(1)) for protein (0.92 to 0.99) was close to but less than 1; for ash (1.03 to 1.12), it was close to but greater than 1; for moisture (0.82 to 0.86), it was less than 1, and for lipid (1.61 to 1.71), it was greater than 1. Deposition rates (change in component weight per unit change in BW) for each chemical component were predicted using derivatives of the function. The mean deposition rates for protein and lipid were 0.141 and 0.286 kg/kg of BW gain, respectively. The deposition rate for protein was generally stable across different BW, whereas that for lipid increased as BW increased. In addition, linear, quadratic, exponential, and logistic functions were fitted to the data to study the relationship between the CT data and chemical components. The linear function was assessed to be the best equation, based on the Bayesian information criterion. The prediction equation for protein (kg) = -1.64 + 0.28 × CT lean (kg), and for lipid (kg) = -0.69 + 1.09 × CT fat (kg), had R(2) values of 0.924 and 0.987, respectively. Sex had no effect (P > 0.05) on the prediction of protein and lipid. The effect of BW was not significant (P > 0.05) for the prediction of lipid, but it was significant (P > 0 0.05) for the prediction of protein. However, the addition of BW to the base prediction equation for protein resulted in an increase of only 0.013 in the R(2) value. It was concluded from this study that CT scanning has great potential as a nondestructive technology for estimating the physical and chemical body composition of pigs. Additional research is required to validate the utility and accuracy of the prediction equations. PMID:21821817

Arthur, P F; Barchia, I M; Giles, L R; Eamens, G J

2011-12-01

311

Recent laboratory and field observations of the chemical composition of atmospheric nanoparticles  

NASA Astrophysics Data System (ADS)

This presentation will focus on understanding the species and mechanisms that are responsible for the formation and growth of atmospheric nanoparticles. We report 10 - 40 nm diameter nanoparticle chemical composition measurements performed in two coastal sites (Mace Head, Ireland, and Lewes, Delaware USA) and two forested sites (Hyytiälä, Finland, and Manitou Forest, Colorado USA) with the recently-developed High Resolution Time-of-Flight Thermal Desorption Chemical Ionization Mass Spectrometer (HTOF-TDCIMS). These field measurements are supplemented by laboratory experiments of particle formation and growth performed at NCAR using a flow tube apparatus and a Teflon bag reaction chamber, and by thermodynamic modeling. Together, our field and laboratory observations point to crucial roles played in nanoparticle growth by two compounds: organic acids and organonitrates. The first, organic acids, are major contributors to the organic fraction in sub-20 nm diameter biogenic nanoparticles but appear to be less abundant in the organic fraction of larger particles, the latter of which are dominated by multifunctional carbonyl- and alcohol-containing compounds. The observed changes in chemical composition of the organic fraction as a function of particle size are supported by thermodynamic modeling results. The second, organonitrates, are commonly found in ambient nanoparticles as small as 10 nm in diameter. However unlike organic acids, organonitrates become increasingly more important in nanoparticle growth as particle size increases. Laboratory experiments suggest that organonitrates formed from the nitrate radical oxidation of biogenic organic compounds, a subset of total organonitrates, exhibit particularly low volatility and can thus partition into the smallest nanoparticles. This is confirmed by HTOF-TDCIMS measurements of 10 - 20 nm diameter particles, which show that particulate phase organonitrates peak in the morning, shortly following the period where organonitrates are believed to be formed by nitrate radical chemistry.

Smith, J. N.; Winkler, P.; Hildebrandt Ruiz, L.; Lawler, M. J.; Ortega, J.; Fry, J.; Barsanti, K. C.; McMurry, P. H.; Johnston, M. V.

2012-12-01

312

On the Morphology and Chemical Composition of the HR 4796A Debris Disk  

NASA Astrophysics Data System (ADS)

We present resolved images of the HR 4796A debris disk using the Magellan adaptive optics system paired with Clio-2 and VisAO. We detect the disk at 0.77 ?m, 0.91 ?m, 0.99 ?m, 2.15 ?m, 3.1 ?m, 3.3 ?m, and 3.8 ?m. We find that the deprojected center of the ring is offset from the star by 4.76 ± 1.6 AU and that the deprojected eccentricity is 0.06 ± 0.02, in general agreement with previous studies. We find that the average width of the ring is 14+3-2% (11.1+2.4-1.6 AU), also comparable to previous measurements. Combining our new scattered light data with archival Hubble Space Telescope images at ~0.5-2 ?m, along with previously unpublished Spitzer/MIPS thermal emission data and all other literature thermal data, we set out to constrain the chemical composition of the dust grains. After testing 19 individual root compositions and more than 8400 unique mixtures of these compositions, we find that good fits to the scattered light alone and thermal emission alone are discrepant, suggesting that caution should be exercised if fitting to only one or the other. When we fit to both data sets simultaneously, we find that silicates and organics are generally the most favored, while large abundances of water ice are usually not favored. These results suggest the HR 4796A dust grains are similar to interstellar dust and solar system comets, though improved modeling is necessary to place better constraints on the exact chemical composition of the dust. This paper includes data obtained at the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Rodigas, Timothy J.; Stark, Christopher C.; Weinberger, Alycia; Debes, John H.; Hinz, Philip M.; Close, Laird; Chen, Christine; Smith, Paul S.; Males, Jared R.; Skemer, Andrew J.; Puglisi, Alfio; Follette, Katherine B.; Morzinski, Katie; Wu, Ya-Lin; Briguglio, Runa; Esposito, Simone; Pinna, Enrico; Riccardi, Armando; Schneider, Glenn; Xompero, Marco

2015-01-01

313

Chemical vapor deposited diamond-on-diamond powder composites (LDRD final report)  

SciTech Connect

Densifying non-mined diamond powder precursors with diamond produced by chemical vapor infiltration (CVI) is an attractive approach for forming thick diamond deposits that avoids many potential manufacturability problems associated with predominantly chemical vapor deposition (CVD) processes. The authors developed techniques for forming diamond powder precursors and densified these precursors in a hot filament-assisted reactor and a microwave plasma-assisted reactor. Densification conditions were varied following a fractional factorial statistical design. A number of conclusions can be drawn as a result of this study. High density diamond powder green bodies that contain a mixture of particle sizes solidify more readily than more porous diamond powder green bodies with narrow distributions of particle sizes. No composite was completely densified although all of the deposits were densified to some degree. The hot filament-assisted reactor deposited more material below the exterior surface, in the interior of the powder deposits; in contrast, the microwave-assisted reactor tended to deposit a CVD diamond skin over the top of the powder precursors which inhibited vapor phase diamond growth in the interior of the powder deposits. There were subtle variations in diamond quality as a function of the CVI process parameters. Diamond and glassy carbon tended to form at the exterior surface of the composites directly exposed to either the hot filament or the microwave plasma. However, in the interior, e.g. the powder/substrate interface, diamond plus diamond-like-carbon formed. All of the diamond composites produced were grey and relatively opaque because they contained flawed diamond, diamond-like-carbon and glassy carbon. A large amount of flawed and non-diamond material could be removed by post-CVI oxygen heat treatments. Heat treatments in oxygen changed the color of the composites to white.

Panitz, J.K.; Hsu, W.L.; Tallant, D.R.; McMaster, M.; Fox, C.; Staley, D.

1995-12-01

314

What Do Microbes Encounter at the Plant Surface? Chemical Composition of Pea Leaf Cuticular Waxes1  

PubMed Central

In the cuticular wax mixtures from leaves of pea (Pisum sativum) cv Avanta, cv Lincoln, and cv Maiperle, more than 70 individual compounds were identified. The adaxial wax was characterized by very high amounts of primary alcohols (71%), while the abaxial wax consisted mainly of alkanes (73%). An aqueous adhesive of gum arabic was employed to selectively sample the epicuticular wax layer on pea leaves and hence to analyze the composition of epicuticular crystals exposed at the outermost surface of leaves. The epicuticular layer was found to contain 74% and 83% of the total wax on adaxial and abaxial surfaces, respectively. The platelet-shaped crystals on the adaxial leaf surface consisted of a mixture dominated by hexacosanol, accompanied by substantial amounts of octacosanol and hentriacontane. In contrast, the ribbon-shaped wax crystals on the abaxial surface consisted mainly of hentriacontane (63%), with approximately 5% each of hexacosanol and octacosanol being present. Based on this detailed chemical analysis of the wax exposed at the leaf surface, their importance for early events in the interaction with host-specific pathogenic fungi can now be evaluated. On adaxial surfaces, approximately 80% of Erysiphe pisi spores germinated and 70% differentiated appressoria. In contrast, significantly lower germination efficiencies (57%) and appressoria formation rates (49%) were found for abaxial surfaces. In conclusion, the influence of the physical structure and the chemical composition of the host surface, and especially of epicuticular leaf waxes, on the prepenetration processes of biotrophic fungi is discussed. PMID:16113231

Gniwotta, Franka; Vogg, Gerd; Gartmann, Vanessa; Carver, Tim L.W.; Riederer, Markus; Jetter, Reinhard

2005-01-01

315

Chemical, isotopic, and gas compositions of selected thermal springs in Arizona, New Mexico, and Utah  

USGS Publications Warehouse

Twenty-seven thermal springs in Arizona, New Mexico, and Utah were sampled for detailed chemical and isotopic analysis. The springs issue sodium chloride, sodium bicarbonate, or sodium mixed-anion waters of near neutral (6.2) to alkaline (9.2) pH. High concentrations of fluoride, more than 8 milligrams per liter, occur in Arizona in waters from Gillard Hot Springs, Castle Hot Springs, and the unnamed spring of Eagle Creek, and in New Mexico from springs along the Gila River. Deuterium compositions of the thermal waters cover the same range as those expected for meteoric waters in the respective areas. The chemical compositions of the thermal waters indicate that Thermo Hot Springs in Utah and Gillard Hot Springs in Arizona represent hydrothermal systems which are at temperatures higher than 125 deg C. Estimates of subsurface temperature based on the quartz and Na-K-Ca geothermometer differ by up to 60 deg C for Monroe, Joseph, Red Hill, and Crater hot springs in Utah. Similar conflicting estimates of aquifer temperature occur for Verde Hot Springs, the springs near Clifton and Coolidge Dam, in Arizona; and the warm springs near San Ysidro, Radium Hot Springs, and San Francisco Hot Springs, in New Mexico. Such disparities could result from mixing, precipitation of calcium carbonate, or perhaps appreciable concentrations of magnesium. (Woodard-USGS)

Mariner, R.H.; Presser, T.S.; Evans, W.C.

1977-01-01

316

Mechano-Chemical Preparation of Powder QUARTZ/TiO2 Composite Particles  

NASA Astrophysics Data System (ADS)

Titanium dioxide pigment is a white pigment of high performance. However, its production could cause severe environmental and resource problems. In this paper, powder quartz/TiO2 composite particles (PQ/TCP), a type of core (powder quartz)-shell(TiO2) composite powder, were prepared by a mechano-chemical method. The pigment properties of PQ/TCP and the mechanism of the mechano-chemical reaction between quartz and TiO2 were investigated. Orthogonal analyses of experimental vairables showed optimal pigment characteristics of PQ/TCP under the following conditions: 4 h of activation for powder quartz, mixing/grinding at 1000 rpm for 1 h, with a mixing slurry made of 50% powder quartz and 0.4% dispersant. Powder quartz was evenly coated by TiO2 and the Si-O-Ti bond was formed between powder quartz and TiO2 in PQ/TCP as revealed by FTIR analyses and confirmed by surface thermodynamic calculation.

Du, Gao-Xiang; He, Hao; Liao, Li-Bing; Wang, Li-Juan

2013-04-01

317

Seasonal Variation, Chemical Composition and Antioxidant activity of Brazilian Propolis Samples  

PubMed Central

Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin–Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being ?- and ?-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis. PMID:18955317

Teixeira, Érica Weinstein; Message, Dejair; Negri, Giuseppina; Stringheta, Paulo César

2010-01-01

318

Quantitative imaging of chemical composition using dual-energy, dual-source CT  

NASA Astrophysics Data System (ADS)

Dual-energy x-ray material decomposition has been proposed as a noninvasive quantitative imaging technique for more than 20 years. In this paper, we summarize previously developed dual-energy material decomposition methods and propose a simple yet accurate method for quantitatively measuring chemical composition in vivo. In order to take advantage of the newly developed dual-source CT, the proposed method is based upon post reconstruction (image space) data. Different from other post reconstruction methods, this method is designed to directly measure element composition (mass fraction) in a tissue by a simple table lookup procedure. The method has been tested in phantom studies and also applied to a clinical case. The results showed that this method is capable of accurately measuring elemental concentrations, such as iron in tissue, under low noise imaging conditions. The advantage of this method lies in its simplicity and fast processing times. We believe that this method can be applied clinically to measure the mass fraction of any chemical element in a two-material object, such as to quantify the iron overload in the liver (hemochromatosis). Further investigations on de-noising techniques, as well as clinical validation, are merited.

Liu, Xin; Primak, Andrew N.; Yu, Lifeng; McCollough, Cynthia H.; Morin, Richard L.

2008-03-01

319

Structure, chemical composition and mechanical properties of coronal cementum in human deciduous molars  

PubMed Central

Objectives It was hypothesized that the coronal cementum containing collagen forms a weak junction with enamel unlike the well integrated DEJ and CDJ. Methods The hypothesis was investigated in two parts: 1) Evaluate the structure, chemical composition and mechanical properties of coronal cementum and its junction with enamel using scanning electron microscopy, micro-X-ray computed tomography, and atomic force microscopy. The chemical composition and mechanical properties were determined by evaluating the spatial variations of inorganic (PO43? ?1 mode at 960 cm?1) and organic (C-H deformation at 1452 cm?1; C-H stretch at 2940 cm?1) contents using Raman microspectroscopy and elastic modulus and hardness values using nanoindentation. 2). Estimate the strength and evaluate the microstructure of coronal cementum interface with enamel using SEM and MicroXCT™. Results & Conclusions Coronal cementum is heterogeneous because it is a combination of laminar acellular afibrillar cementum and acellular extrinsic fiber cementum with relatively higher organic content. It integrates micromechanically via a scallop-like weak interface with enamel unlike the biomechanically efficient DEJ and CDJ and is continuous with primary root cementum. A single tooth could exhibit all three types of cementum enamel junctions; an overlap, butt and a gap depending on the sectioning plane. The elastic modulus of coronal cementum (11.0 ± 5.8 GPa) is significantly lower (p < 0.05; Student’s t-test with 95% confidence interval) than primary cementum (15.8 ± 5.3 GPa). PMID:19464049

Ho, Sunita P.; Senkyrikova, Pavla; Marshall, Grayson W.; Yun, Wenbing; Wang, Yong; Karan, Kunal; Li, Cheng; Marshall, Sally J.

2009-01-01

320

The influence of chemical composition of commercial lemon essential oils on the growth of Candida strains.  

PubMed

Candida yeasts are saprophytes naturally present in the environment and forming colonies on human mucous membranes and skin. They are opportunistic fungi that cause severe and even fatal infections in immunocompromised individuals. Several essential oils, including eucalyptus, pine, cinnamon and lemon, have been shown to be effective against Candida strains. This study addresses the chemical composition of some commercial lemon essential oils and their antifungal potential against selected Candida yeast strains. Antifungal potential and minimum inhibitory concentrations were determined for six commercial lemon essential oils against five Candida yeast strains (Candida albicans 31, Candida tropicalis 32, Candida glabrata 33, Candida glabrata 35 and Candida glabrata 38). On the basis of the GCMS analysis, it was found that the tested lemon essential oils had different chemical compositions, but mostly, they contained almost exclusively terpenes and oxygenated terpenes. The tests show that antifungal potential of lemon essential oils against Candida yeast strains was related to the high content of monoterpenoids and the type of Candida strains. From six tested commercial oils, only four (ETJA, Vera-Nord, Avicenna-Oil and Aromatic Art) shows antifungal potential against three Candida species (C. albicans, C. tropicalis and C. glabrata). Vera-Nord and Avicenna-Oil show the best activity and effectively inhibit the growth of the C. albicans strain across the full range of the concentrations used. Our study characterises lemon essential oils, which could be used as very effective natural remedies against candidiasis caused by C. albicans. PMID:24436010

Bia?o?, M; Krzy?ko-?upicka, T; Kosza?kowska, M; Wieczorek, P P

2014-02-01

321

Chemical composition, antibacterial, antifungal and antioxidant activities of Algerian Eryngium tricuspidatum L. essential oil.  

PubMed

This study describes the chemical composition and the antibacterial, antifungal and antioxidant activities of the essential oil extracted from aerial parts of the Algerian Eryngium tricuspidatum L., obtained by hydrodistillation and analysed by using the combination of gas chromatography (GC) and GC/mass spectrometry. A total of 63 compounds were identified accounting for 93.1% of the total oil. Chemical composition of oil was characterised by a high proportion of oxygenated sesquiterpenes (49.6%) among which ?-bisabolol (32.6%) was the predominant compound. The sesquiterpene hydrocarbons represent the second major fraction (31.9%) with ?-curcumene (6.5%) being the predominant one. Antibacterial and antifungal activities of the oil were tested using the micro-well determination of minimum inhibitory concentration (MIC) assay against eleven bacteria and two Candida species. It was found that the aerial parts of E. tricuspidatum exhibited interesting antibacterial and anticandidal activities (MIC = 9 ?g/mL against several strains of bacteria and MIC = 4.6 ?g/mL against Candida albicans). The antioxidant effect of this oil was evaluated using the 2,2-diphenyl-l-1-picrylhydrazil (DPPH) and ferric reducing antioxidant power (FRAP) assays. Results revealed significant activities (DPPH method: IC?? = 510 ?g/mL; FRAP assay: reducing power of oil increases from 0.0188 at 5 ?g/mL to 0.5016 at 1000 ?g/mL). PMID:24559136

Merghache, Djamila; Boucherit-Otmani, Zahia; Merghache, Salima; Chikhi, Ilyas; Selles, Chaouki; Boucherit, Kebir

2014-01-01

322

Effect of chemical composition and density of the pelvic structure in intracavitary brachytherapy dosimetry  

NASA Astrophysics Data System (ADS)

High dose rate (HDR) and low dose rate (LDR) intracavitary brachytherapies dosimetry in clinical practice are typically performed by commercial treatment planning systems. However, these systems do not fully consider the heterogeneities present in the real structure of the patient. The aim of this work is to obtain isodose curves and surfaces around the usual array of sources used in LDR ( 137Cs) and HDR ( 192Ir) intracavitary brachytherapy by Monte Carlo simulation, considering the real anatomic structure, density and chemical composition of media and tissues from the female pelvic region. The structural information was obtained from computed tomography images in the DICOM format. A voxel phantom (VP) was developed to perform ionizing radiation transport, considering the gamma spectrum of 137Cs and 192Ir. The absorbed dose was computed within each voxel of 2×2×3 mm 3. Four materials were considered in the VP—air, fat, muscle tissue and bone; however, one material per voxel was defined. Results show and quantify the effect of density and chemical composition of the medium on the absorbed dose distribution. According to them, the treatment planning systems underestimate the absorbed dose by 8% approximately for both radionuclides. In a heterogeneous medium, the absorbed dose distribution of 192Ir is more irregular than that of 137Cs but spatially better defined.

Chávez-Aguilera, N.; Torres-García, E.; Mitsoura, E.

2011-03-01

323

Larvicidal efficacies and chemical composition of essential oils of Pinus sylvestris and Syzygium aromaticum against mosquitoes  

PubMed Central

Objective To assess the chemical composition and mosquito larvicidal potentials of essential oils of locally sourced Pinus sylvestris (P. sylvestris) and Syzygium aromaticum (S. aromaticum) against Aedes aegypti (A. aegypti) and Culex quinquefasciatus (C. quinquefasciatus). Method The chemical composition of the essential oils of both plants was determined using GC-MS while the larvicidal bioassay was carried out using different concentrations of the oils against the larvae of A. aegypti and C. quinquefasciatus in accordance with the standard protocol. Results The results as determined by GC-MS showed that oil of S. aromaticum has eugenol (80.5%) as its principal constituent while P. sylvestris has 3-Cyclohexene-1-methanol, .alpha., .alpha.4-trimethyl (27.1%) as its dominant constituent. Both oils achieved over 85% larval mortality within 24 h. The larvae of A. aegypti were more susceptible to the oils [LC50 (S. aromaticum)=92.56 mg/L, LC50(P. sylvestris)=100.39 mg/L] than C. quinquefasciatus [LC50(S. aromaticum)=124.42 mg/L; LC50(P. sylvestris)=128.00 mg/L]. S. aromaticum oil was more toxic to the mosquito larvae than oil of P. sylvestris but the difference in lethal concentrations was insignificant (P>0.05). Conclusion The results justify the larvicidal potentials of both essential oils and the need to incorporate them in vector management and control. PMID:24144127

Fayemiwo, Kehinde Adenike; Adeleke, Monsuru Adebayo; Okoro, Ovie Princewill; Awojide, Shola Hezekiah; Awoniyi, Ilias Olufemi

2014-01-01

324

On the physical mechanism of fast variability in the chemical composition of the solar wind  

NASA Astrophysics Data System (ADS)

Considerable variations in the chemical composition of the solar wind (particularly, the helium-to-hydrogen ratio, [He (++) ]/[H (+) ]) is a well known phenomenon. Moreover, as was established recently by the ``Plasma-F'' experiment aboard Spektr-R satellite, such variations can be very fast (e.g., by 3-4 times during 10 s). Unfortunately, the FIP (First Ionization Potential) effect, often invoked for explanation of the minor-element abundance in the solar atmosphere, is hardly applicable here because of the high ionization potential of helium. Our alternative model attributes the above-mentioned variations in [He (++) ]/[H (+) ] to the intermittent outflow of the solar wind from the coronal magnetic flux tubes with substantially different lifetimes and, therefore, a different degree of gravitational separation of the plasma components. As follows from the solution of multi-fluid hydrodynamic equations, this effect can easily give a variation in the relative helium abundance by an order of magnitude between the short- and long-lived flux tubes. Besides, it can be conjectured that changes in the chemical composition should be associated with fluctuations in the direction of the solar wind and/or its magnetic field; but this subject requires a further investigation. In conclusion, we believe that the gravitational separation of plasma components in the magnetic tubes with different lifetimes is a robust and generic mechanism for explanation of the element abundance in the solar wind at all temporal scales.

Dumin, Yurii

325

Mineral and chemical composition of the Jezersko meteorite—A new chondrite from Slovenia  

NASA Astrophysics Data System (ADS)

The Jezersko meteorite is a newly confirmed stony meteorite found in 1992 in the Karavanke mountains, Slovenia. The meteorite is moderately weathered (W2), indicating short terrestrial residence time. Chondrules in partially recrystallized matrix are clearly discernible but often fragmented and have mean diameter of 0.73 mm. The meteorite consists of homogeneous olivine (Fa19.4) and low-Ca pyroxenes (Fs16.7Wo1.2), of which 34% are monoclinic, and minor plagioclase (Ab83An11Or6) and Ca-pyroxene (Fs6Wo45.8). Troilite, kamacite, zoned taenite, tetrataenite, chromite, and metallic copper comprise about 16.5 vol% of the meteorite. Phosphates are represented by merrillite and minor chlorapatite. Undulatory extinction in some olivine grains and other shock indicators suggests weak shock metamorphism between stages S2 and S3. The bulk chemical composition generally corresponds to the mean H chondrite composition. Low siderophile element contents indicate the oxidized character of the Jezersko parent body. The temperatures recorded by two-pyroxene, olivine-chromite, and olivine-orthopyroxene geothermometers are 854 °C, 737-787 °C, and 750 °C, respectively. Mg concentration profiles across orthopyroxenes and clinopyroxenes indicate relatively fast cooling at temperatures above 700 °C. A low cooling rate of 10 °C Myr-1 was obtained from metallographic data. Considering physical, chemical, and mineralogical properties, meteorite Jezersko was classified as an H4 S2(3) ordinary chondrite.

Miler, Miloš; Ambroži?, Bojan; Mirti?, Breda; Gosar, Mateja; Å turm, Sašo.; Dolenec, Matej; Jeršek, Miha

2014-10-01

326

Effect of chemical vapor infiltration on erosion and thermal properties of porous carbon\\/carbon composite thermal insulation  

Microsoft Academic Search

A highly porous carbon\\/carbon composite, known as carbon bonded carbon fiber (CBCF) and used as thermal insulation, was densified by chemical vapor infiltration (CVI). The erosion resistance, thermal conductivity and thermal expansion coefficient were measured with interest to utilization of the CVI densified composite as erosion protection in furnaces that employ inert gas quenching. It was found that the erosion

R. I Baxter; R. D Rawlings; N Iwashita; Y Sawada

2000-01-01

327

Combined effect of flux and welding parameters on chemical composition and mechanical properties of submerged arc weld metal  

Microsoft Academic Search

Rotatable designs based on statistical experiments for mixtures have been developed to predict the combined effect of flux mixture and welding parameters on submerged arc weld metal chemical composition and mechanical properties. Bead-on-plate weld deposits on low carbon steel plates were made at different flux composition and welding parameter combinations. The results show that flux mixture related variables based on

P. Kanjilal; T. K. Pal; S. K. Majumdar

2006-01-01

328

Chemical composition and complex refractive index of Saharan Mineral Dust at Izaña, Tenerife (Spain) derived by electron microscopy  

Microsoft Academic Search

Samples from two strong homogeneous dust plumes from the Saharan desert reaching Izaña (Tenerife, Spain) in July and August 2005 were taken with a miniature impactor system and filter samplers. Size, aspect ratio and chemical composition of more than 22,000 individual particles were studied by scanning electron microscopy. The mineralogical phase composition of about 200 particles was investigated by transmission

Konrad Kandler; Nathalie Benker; Ulrich Bundke; Emilio Cuevas; Martin Ebert; Peter Knippertz; Sergio Rodríguez; Lothar Schütz; Stephan Weinbruch

2007-01-01

329

Measurement of the chemical composition of the ultra-high-energy cosmic rays with the Pierre Auger Observatory  

E-print Network

The Pierre Auger Observatory infers the chemical composition of ultra-high-energy cosmic rays through two independent detection techniques. The Fluorescence Detector (FD) measures the longitudinal profile of high energy air showers and can determine the depth of the shower maximum $X_{max}$, which is sensitive to the chemical composition of the primary cosmic rays. Additionally, measurements by the Surface Detector (SD) provide independent experimental observables based on the muonic shower component to analyze the chemical composition. We present the results for the $X_{max}$ distributions and the mass composition results measured by the FD and the SD for the energies $E \\geq 10^{18}$\\,eV. The data will be compared with the expectations for proton and iron primaries according to different hadronic interaction models.

Plum, Matthias

2015-01-01

330

Nature's chemicals and synthetic chemicals: Comparative toxicology  

Microsoft Academic Search

The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural

B. N. Ames; M. Profet; L. S. Gold

1990-01-01

331

Chemical Accelerators The phrase "chemical accelerators"  

E-print Network

Meetings Chemical Accelerators The phrase "chemical accelerators" is scarcely older than for one or two dozen people grew to include nearly a hundred. Chemical accelerators is a name sug- gested by one of us for devices that produce beams of chemically interesting species at relative kinetic

Zare, Richard N.

332

Chemical information science coverage in Chemical Abstracts.  

PubMed

For many years Chemical Abstracts has included in its coverage publications on chemical documentation or chemical information science. Although the bulk of those publications can be found in section 20 of Chemical Abstracts, many relevant articles were found scattered among 39 other sections of CA in 1984-1985. In addition to the scattering of references in CA, the comprehensiveness of Chemical Abstracts as a secondary source for chemical information science is called into question. Data are provided on the journals that contributed the most references on chemical information science and on the languages of publication of relevant articles. PMID:3558505

Wiggins, G

1987-02-01

333

All year round chemical composition of aerosol reaching the inner Antarctic Plateau (Dome C - East Antarctica)  

NASA Astrophysics Data System (ADS)

Since 2005, continuous, all-year-round aerosol sampling was carried out at Dome C (Central East Antarctica, 3233 m a.s.l., about 1100 km far from the coast-line), in the framework of Station Concordia project. Size-segregated aerosol samples were collected in summer and winter period by using different low- and medium-volume systems, including pre-selected cut-off samplers (with PM10, PM2.5 and PM1 heads) and multi-stage (Andersen 8-stage and Dekati 4-stage) impactors. Sampling resolution and volume range from 1 day to 1 month and from 2.3 to 12 m3/h respectively. Aerosol study at Dome C aims to improve our knowledge on present day source intensity, transport efficiency and pathways (including stratosphere-to-troposphere interchanges) of particles reaching internal sites of Antarctica and to understand size- and chemical-fractionation effects occurring during the transport (by comparison with coastal aerosol composition). Besides, more information on atmosphere-snow interaction, including depositional and post depositional processes, as well as the effect of sublimation/condensation processes on snow surface, improves the reconstruction of past atmosphere composition from EPICA-DC deep ice core, drilled in the same site. Here we report some results of the chemical composition of the Antarctic background aerosol reaching Dome C, pointing out the seasonal pattern and the temporal trend of some ionic components used as tracers of sea spray, marine biogenic and crustal emissions. The atmospheric load in the summer is more than one order of magnitude lower than that measured in coastal sites and chemical composition is dominated by secondary aerosol, mainly originated by biological marine activity (S-cycle), and distributed in the finest aerosol fractions. H2SO4 from oxidation of biogenic DMS is the main component, while the contribution of HNO3 to the ionic budget is difficult to evaluate because of the re-emission into the atmosphere from the filter surface (acidic deposition). The ionic load was even lower in winter, when secondary biogenic aerosol decreases and larger particles from primary source (especially from sea spray) prevail. Sea spray plays a significant role in winter and spring aerosol, when more frequent and effective transport events from marine areas around Antarctica occur. In the same transport conditions, even relatively large dust content (as revealed by Ca2+ concentration) is measured in the Dome C aerosol. Longer observations performed with higher temporal resolutions, yield greater information about the relationship between atmospheric circulation patterns and the load and chemical composition of atmospheric aerosol reaching DC in different seasons. Fractionating effects leading to a reduction of sulphate/sodium ratio (used as marker of "frost flower" source) seem generally do not affect in a significant way the winter aerosol composition, even if few negative values of non-sea salt sulphate were calculated along the whole analyzed period. This evidence could show that sea spray aerosol from frost flower can reach the inner Antarctic plateau when particular transport processes occurs.

Udisti, R.; Becagli, S.; Castellano, E.; Cerri, O.; Marino, F.; Morganti, A.; Nava, S.; Rugi, F.; Severi, M.; Traversi, R.

2009-04-01

334

Chemical and isotope compositions of nitric thermal water of Baikal rift zone  

NASA Astrophysics Data System (ADS)

Three types of hydrotherms (nitric, carbonaceous and methane) are distinguished within the Baikal Rift Zone. The unloading sites of nitric therms are mostly located in the central and north-eastern parts of the Rift. Several chemical types are found among nitric therms (Pinneker, Pisarsky, Lomonosov, 1968; Lomonosov, 1974, etc.). The formation of terms being various in chemical compositions is associated with effect of several factors, i.e. various chemical, mineralogical compositions of rocks, various temperatures, extent of interaction in water-rock system, etc. The ratio data of water oxygen and hydrogen isotopes of the studied thermal springs indicate that water is largely of meteoric origin. All established ratios of oxygen (?18OSMOW = -19.5‰ - -17.5‰) and hydrogen (?DSMOW = -155‰ - - 130‰) isotopes are along the line of meteoric waters. Oxygen values from -20‰ to -5‰ are characteristic of the current meteoric and surface waters in the region. The average value equals -16.5‰ in Lake Baikal. By our data, a large group with oxygen lighter isotope composition that corresponds to isotope ratio being specific for glaciers is revealed in fissure-vein waters. Significant shift toward the oxygen getting heavier is observed in some springs. It is mostly observed in the springs that form chemical composition within the area of the intrusive and metamorphic rock distribution. As a result of hydrolysis reaction of alumosilicates, heavy isotope passes from rocks into water molecule, whereas oxygen heavy isotope passes from rocks into solutes during decomposition of carbonates. High contents of fluoride and sulfate-ions are specific feature of the Baikal Rift Zone most nitric therms. Water is tapped in one of the drill holes, where fluoride-ion dominates in its anion composition (46.7 mg/dm3) and pH reaches 10, 12. The sulphate sulphur isotope composition studies carried out allow to conclude that its heavy isotope (?34SCDT = +25‰ - +30‰) prevails in the therms. Sulphate-ion enters solution not as a result of sulfide oxidation, but dissolution of sulphate minerals of may be originally sedimentary and magmatic rocks. Microelement contents in waters depend on total mineralization. In particular, this regulation is clearly observed for rare alkaline and alkaline-earth elements. We established dependence of one microelement concentrations on temperature of solutions (Sc, Al, W) and that of the other ones - on extent of water - rock (Sr, Ba) interaction. Active use of thermal water for purposes of thermal energetic can contribute to inflow of highly mineralized solutions into water collecting reservoir and result in breakdowns of heat-net work. The study has been carried out with financial support of RFBR. Grant N09-05-00726, Integration Project N87 of SB RAS.

Plyusnin, A. M.; Chernyavsky, M. K.; Peryazeva, E. G.

2010-05-01

335

Comparison of the chemical compositions and nutritive values of various pumpkin (Cucurbitaceae) species and parts  

PubMed Central

Pumpkins have considerable variation in nutrient contents depending on the cultivation environment, species, or part. In this study, the general chemical compositions and some bioactive components, such as tocopherols, carotenoids, and ?-sitosterol, were analyzed in three major species of pumpkin (Cucurbitaceae pepo, C. moschata, and C. maxima) grown in Korea and also in three parts (peel, flesh, and seed) of each pumpkin species. C. maxima had significantly more carbohydrate, protein, fat, and fiber than C. pepo or C. moschata (P < 0.05). The moisture content as well as the amino acid and arginine contents in all parts of the pumpkin was highest in C. pepo. The major fatty acids in the seeds were palmitic, stearic, oleic, and linoleic acids. C. pepo and C. moschata seeds had significantly more ?-tocopherol than C. maxima, whose seeds had the highest ?-carotene content. C. pepo seeds had significantly more ?-sitosterol than the others. Nutrient compositions differed considerably among the pumpkin species and parts. These results will be useful in updating the nutrient compositions of pumpkin in the Korean food composition database. Additional analyses of various pumpkins grown in different years and in different areas of Korea are needed. PMID:22413037

Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun

2012-01-01

336

Fine Aerosol Chemical Composition at the ARM Southern Great Plains Site During the 2003 Aerosol IOP  

NASA Astrophysics Data System (ADS)

Key aerosol properties were characterized by a number of research groups during an Intensive Observation Period (IOP, May 2003) at the Southern Great Plains (SGP) site as part of the U.S. DOE Atmospheric Radiation Measurement (ARM) program. To compliment the goal of gaining an understanding of aerosol optical properties and their contributions to aerosol and cloud radiative effects, we measured fine (d < 1 ? m) aerosol chemical composition and mass concentrations at the SGP Central Facility surface site. Aerosol ionic components, including ammonium, sulfate, nitrate, potassium, calcium, magnesium, sodium, chloride, oxalate, formate, and acetate, were measured during the daytime using a particle-into-liquid sampler coupled to ion chromatography technique at a time resolution of 8 min and a limit of detection (LOD) of 0.1 ? g m-3. The results showed that ammonium and sulfate were the dominant ions with a typical molar ratio close to 2 to 1; potassium and nitrate were prominent only on a few days and were mostly below LOD; oxalate was present in nearly half of the samples but at a very low level; acetate and formate were observed occasionally but the LOD of these two species were significantly higher than the rest of the ions; sodium, chloride, calcium and magnesium were near their LOD for the entire period. We will report the measured aerosol ionic composition and the inferred organic contents derived from aerosol mass concentrations measured using a TEOM instrument. The relationships between chemical composition and aerosol properties such as light scattering and size dependence on relative humidity will be investigated.

Lee, Y.; Bowerman, L.; Song, Z.; Sheridan, P.; Ogren, J.

2003-12-01

337

Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.  

PubMed

Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor. PMID:22022778

Manovic, Vasilije; Anthony, Edward J

2011-12-15

338

Chemical Composition, and Antioxidant and Antimicrobial Activities of Essential Oil of Spearmint (Mentha spicata L.) From Pakistan  

Microsoft Academic Search

Chemical composition, and antioxidant and antimicrobial activities of the essential oil isolated from aerial parts of Mentha spicata L. (spearmint) were investigated. The oil content was found to be 1.2%. A total of 19 chemical constituents were identified in the spearmint oil using GC and GC\\/MS. The main components were carvone (51.7%) and cis-carveol (24.3%), followed by limonene (5.3%), 1,8

Abdullah I. Hussain; Farooq Anwar; Muhammad Shahid; Muhammad Ashraf; Roman Przybylski

2010-01-01

339

Controls on the chemical and isotopic compositions of urban stormwater in a semiarid zone  

NASA Astrophysics Data System (ADS)

The temporal variations in the chemical and isotopic compositions of urban stormwater under different land uses, and their dependence on physical parameters such as precipitation intensity, stormwater discharge, cumulative stormwater volumes and the size of the drainage area, were investigated in the coastal city of Ashdod, Israel. During 2000/2001 and 2001/2002, 39 stormwater events were intensively monitored for precipitation distribution and intensity at three stations across the city and for stormwater discharge at seven stations draining 85% of the city area. Thirty nine and 202 precipitation samples were collected and analyzed for chemical and isotopic compositions, respectively as were 149 stormwater samples, collected from the drains during 10 of the 39 events. Because the stormwater stations drained areas of different sizes and land uses, their impact on the stormwater chemistry could be evaluated. Land use had only a minor effect on the concentrations of major ions and trace elements. Conversely, the concentrations and variety of volatile and semi-volatile organic compounds were significantly higher in stormwater generated in the industrial area than in that draining from residential areas. Ion and trace-metal concentrations were very low (below drinking-water standards) in 97% of the stormwater samples collected from all drains. Stormwater concentrations were higher in stations draining a larger area, thereby linking concentrations to the length of stormwater flowpaths. A first-flush effect was documented on both a seasonal and an event basis for both ions and trace elements. The high concentrations of fecal coliform bacteria exceeded the drinking-water standards and displayed a random pattern. The isotopic ratios of oxygen and hydrogen in the stormwater suggest very little exposure to the atmosphere, resulting in very limited fractionation. The presence of fecal coliforms, ammonium in some samples, and specific ratios of oxygen and nitrogen isotopes, suggest that although the sewer and stormwater=collection systems are separated, wastewater, possibly from overflowing sewers, contributed to the drained stormwater. The chemical composition of stormwater collected from the residential areas in the city of Ashdod suggests that this water can be reused with little treatment (e.g. filtering and chlorination).

Asaf, L.; Nativ, R.; Shain, D.; Hassan, M.; Geyer, S.

2003-04-01

340

Impact of raized bogs on export of carbon and river water chemical composition in Western Siberia  

NASA Astrophysics Data System (ADS)

Bogs play an important role in functioning of the biosphere. Specific geochemical environment of the bogs results in formation of the special biogeochemical cycle of the elements. Processes of decay and transformation of organic material define the reductive conditions of bog water, form and migratory mobility of the chemical elements. Particular interest in recent years is aroused by the question of content and dynamics of the carbon in bog and river water according to indicated natural and climatic changes on the territory. The most important parts of the carbon balance in bog ecosystems together with processes of exhalation from deposit surface in the form of CO2 is its export with river water. The results of research carried out in scientific station "Vasyugansky" in south taiga subzone of Western Siberia showed that chemical composition of raised bog water includes high amounts of total iron (2,13 mg/l), ammonium ions (5,33 mg/l), humic and fulvic acids (5,21 mg/l and 45,8 mg/l), dissolved organic carbon (69,1 mg/l), COD (236,93 mgO/l), there are low mineralization and indicators of pH. Carbon comes in bog water in organic compounds: carboxylic acids, phenols, aromatic and paraffin hydrocarbons, organic phosphates, phthalates and other compounds. Formation of river waters composition in the Western Siberia takes place in the following context: high level of bogged river catchments (sometimes up to 70%), excess humidification and low heat provision. Basing on the results of study of hydrochemical runoff in small and medium rivers with different levels of bogged in river catchments (Chaya, Bakchar, Klyuch, Gavrilovka) it was noted that raised bog influence on river waters chemical composition shows in ion runoff decrease, organic substances runoff increase, increase of amounts of total iron, ammonium irons and water pH indicators decrease. Study of humic matters migration is very important in the context of formation of flexible complexes of humic and fulvic acids and heavy metals, which should be taken into account when in waterlogged regions constructing large industrial projects and in formation of water removing.

Voistinova, Elena

2010-05-01

341

Chemical composition profiles during alkaline flooding at different temperatures and extended residence times  

SciTech Connect

The objective of this work was to investigate whether or not caustic sweeps the major portion of the reservoir efficiently during an alkaline flood process. It was also the objective of this work to study the state of final equilibrium during a caustic flood through determination of the pH and chemical composition profiles along the porous medium. For this purpose, a long porous medium which provided extended residence times was required. It was necessary to set up the porous medium such that the changes in the pH and chemical composition of the solution could be monitored. Four Berea sandstone cores (8 in. length and1 in. diameter) placed in series provided the desired length and the opportunity for sampling in-between cores. This enabled establishment of pH and chemical composition profiles. The experiments were run at, temperatures up.to 180{degrees}C, and the flow rates varied from 4.8 to 0.2 ft/day. The samples were analyzed for pH and for Si and Al concentrations.The results show that caustic consumption is insignificant for temperatures up to 100{degrees}C. Above 100{degrees}C consumption increases and is accompanied by a significant decrease in pH. The sharp decline in pH also coincides with a sharp decline in concentration of silica in solution. The results also show that alumina is removed from the solution and solubility of alumina ultimately reaches zero. Sharp silica and pH declines take place even in the absence of any alumina in solution. As a result, removal of silica from solution is attributed to the irreversible caustic/rock interaction. This interaction is in the form of chemisorption reactions in which silica is adsorbed onto the rock surface consuming hydroxyl ion. Once these reactions were satisfied, caustic breakthrough occurs at a high pH. However, significant pore volumes of caustic must be injected for completion of the chemisorption.

Aflaki, R.; Handy, L.L.

1992-12-01

342

Chemical composition profiles during alkaline flooding at different temperatures and extended residence times  

SciTech Connect

The objective of this work was to investigate whether or not caustic sweeps the major portion of the reservoir efficiently during an alkaline flood process. It was also the objective of this work to study the state of final equilibrium during a caustic flood through determination of the pH and chemical composition profiles along the porous medium. For this purpose, a long porous medium which provided extended residence times was required. It was necessary to set up the porous medium such that the changes in the pH and chemical composition of the solution could be monitored. Four Berea sandstone cores (8 in. length and1 in. diameter) placed in series provided the desired length and the opportunity for sampling in-between cores. This enabled establishment of pH and chemical composition profiles. The experiments were run at, temperatures up.to 180[degrees]C, and the flow rates varied from 4.8 to 0.2 ft/day. The samples were analyzed for pH and for Si and Al concentrations.The results show that caustic consumption is insignificant for temperatures up to 100[degrees]C. Above 100[degrees]C consumption increases and is accompanied by a significant decrease in pH. The sharp decline in pH also coincides with a sharp decline in concentration of silica in solution. The results also show that alumina is removed from the solution and solubility of alumina ultimately reaches zero. Sharp silica and pH declines take place even in the absence of any alumina in solution. As a result, removal of silica from solution is attributed to the irreversible caustic/rock interaction. This interaction is in the form of chemisorption reactions in which silica is adsorbed onto the rock surface consuming hydroxyl ion. Once these reactions were satisfied, caustic breakthrough occurs at a high pH. However, significant pore volumes of caustic must be injected for completion of the chemisorption.

Aflaki, R.; Handy, L.L.

1992-12-01

343

Chemical composition and insecticidal activity of plant essential oils from Benin against Anopheles gambiae (Giles)  

PubMed Central

Background Insecticide resistance in sub-Saharan Africa and especially in Benin is a major public health issue hindering the control of the malaria vectors. Each Anopheles species has developed a resistance to one or several classes of the insecticides currently in use in the field. Therefore, it is urgent to find alternative compounds to conquer the vector. In this study, the efficacies of essential oils of nine plant species, which are traditionally used to avoid mosquito bites in Benin, were investigated. Methods Essential oils of nine plant species were extracted by hydrodistillation, and their chemical compositions were identified by GC-MS. These oils were tested on susceptible “kisumu” and resistant “ladji-Cotonou” strains of Anopheles gambiae, following WHO test procedures for insecticide resistance monitoring in malaria vector mosquitoes. Results Different chemical compositions were obtained from the essential oils of the plant species. The major constituents identified were as follows: neral and geranial for Cymbopogon citratus, Z-carveol, E-p-mentha-1(7),8-dien-2-ol and E-p-mentha-2,8-dienol for Cymbopogon giganteus, piperitone for Cymbopogon schoenanthus, citronellal and citronellol for Eucalyptus citriodora, p-cymene, caryophyllene oxide and spathulenol for Eucalyptus tereticornis, 3-tetradecanone for Cochlospermum tinctorium and Cochlospermum planchonii, methyl salicylate for Securidaca longepedunculata and ascaridole for Chenopodium ambrosioides. The diagnostic dose was 0.77% for C. citratus, 2.80% for E. tereticornis, 3.37% for E. citriodora, 4.26% for C. ambrosioides, 5.48% for C. schoenanthus and 7.36% for C. giganteus. The highest diagnostic doses were obtained with S. longepedunculata (9.84%), C. tinctorium (11.56%) and C. planchonii (15.22%), compared to permethrin 0.75%. A. gambiae cotonou, which is resistant to pyrethroids, showed significant tolerance to essential oils from C. tinctorium and S. longepedunculata as expected but was highly susceptible to all the other essential oils at the diagnostic dose. Conclusions C. citratus, E. tereticornis, E. citriodora, C. ambrosioides and C. schoenanthus are potential promising plant sources for alternative compounds to pyrethroids, for the control of the Anopheles malaria vector in Benin. The efficacy of their essential oils is possibly based on their chemical compositions in which major and/or minor compounds have reported insecticidal activities on various pests and disease vectors such as Anopheles. PMID:24298981

2013-01-01

344

Chemical Composition of Gas-Phase Oxidation Products from Biogenic Sources in the Southeast US during SOAS  

NASA Astrophysics Data System (ADS)

Reduced species emitted to the atmosphere are chemically transformed by atmospheric oxidants. The measurement of the large number of resulting oxidized compounds is crucial to understand and quantify these transformation processes. We analyzed datasets from four high-resolution time-of-flight chemical ionization mass spectrometers (HRToF-CIMS) during the Southern Oxidant and Aerosol Study (SOAS) in June and July 2013 at the Alabama Supersite in the Southeast U.S. These datasets allow specification and quantification of the multiple gas-phase compounds produced by chemical oxidation. The mass spectrometers used different reagent ions, nitrate (NO3-), acetate (CH3COO-), and iodide (I-). In this study, we will present the chemical composition of isoprene and terpene oxidation products as measured by the different techniques. When comparing the concentration and composition at different conditions (e.g., time of day, NOx levels, aerosol loading, RH), differences in gas-phase composition provide indications of both the changes in chemical processing arising from the different conditions as well as different sensitivities of the reagent ions. We will discuss these differences in terms of bulk chemical parameters such as carbon oxidation state, carbon number and oxygen-to-carbon ratio.

Stark, H.; Massoli, P.; Thompson, S.; Yatavelli, L. R.; Mohr, C.; Brophy, P.; Murschell, T.; Hu, W.; Canagaratna, M.; Krechmer, J.; Junninen, H.; Hakala, J. P.; Day, D. A.; Campuzano Jost, P.; Palm, B. B.; Ortega, A. M.; Kimmel, J.; Cubison, M.; Lopez-Hilfiker, F.; Thornton, J. A.; Baumann, K.; Edgerton, E.; Farmer, D.; Jimenez, J. L.; Jayne, J. T.; Worsnop, D. R.

2013-12-01

345

Chemical composition of snow in the northern Sierra Nevada and other areas  

USGS Publications Warehouse

Melting snow provides a large part of the water used throughout the western conterminous United States for agriculture, industry, and domestic supply. It is an active agent in chemical weathering, supplies moisture for forest growth, and sustains fish and wildlife. Despite its importance, virtually nothing has been known of the chemical character of snow in the western mountains until the present study. Analysis of more than 100 samples, most from the northern Sierra Nevada, but some from Utah, Denver, Colo., and scattered points, shows that melted snow is a dilute solution containing measurable amounts of some or all of the inorganic constituents commonly found in natural water. There are significant regional differences in chemical composition; the progressive increase in calcium content with increasing distance eastward from the west slope of the Sierra Nevada is the most pronounced. The chemical character of individual snowfalls is variable. Some show predominant influence of oceanic salt; others show strong effects of mineralization from continental sources, probably largely dust. Silica and boron were found in about half the samples analyzed for these constituents; precipitation is seldom analyzed for these substances. Results of the chemical analyses for major constituents in snow samples are summarized in the following table. The median and mean values for individual constituents are derived from 41-78 samples of Sierra Nevada snow, 6-18 samples of Utah snow, and 6-17 samples of Denver, Colo., snow. [Table] The sodium, chloride, and perhaps boron found in snow are probably incorporated in moisture-laden air masses as they move over the Pacific Ocean. Silica, although abundant in the silicate-mineral nuclei found in some snowflakes, may be derived in soluble form largely from dust. Calcium, magnesium, and some bicarbonate are probably added by dust of continental origin. The sources of the other constituents remain unknown. When snowmelt comes in contact with the lithosphere, the earlier diversity of chemical type largely disappears. The melt water rapidly increases its content of dissolved solids and becomes calcium magnesium bicarbonate in type. Silica, whose concentration increases more than tenfold, shows the largest gain; calcium and bicarbonate contents also increase markedly. Most of the additional mineral matter is from soft and weathered rock; bicarbonate, however, is largely from the soil atmosphere: Investigators, some reporting as much as a century ago, concentrated attention largely on nitrogen compounds and seldom reported other consituents except chloride and sulfate. The Northern European precipitation-sampling network provides the most comprehensive collection of data on precipitation chemistry, but it does not segregate snow from other forms of precipitation. The present study establishes with confidence the chemical character of snow in the Sierra Nevada, and suggests that the dissolved-solids content of precipitation increases with increasing distance inland from the Pacific Coast.

Feth, John Henry Frederick; Rogers, S.M.; Roberson, Charles Elmer

1964-01-01

346

Spectroscopy of southern Galactic disk planetary nebulae. Notes on chemical composition and emission-line stars  

NASA Astrophysics Data System (ADS)

Aims: We present low resolution spectroscopic observations for a sample of 53 planetary nebulae (PNe) located in the southern sky between Vela and Norma constellations and pertaining to the Galactic disk with expected Galactocentric distance range of 5 to 10 kpc. Methods: We derive nebular chemical composition and plasma parameters with the classical empirical method. For most of the observed objects, this has been done for the first time. We compare our results to published data for PNe of the Galactic bulge and PNe in the inner-disk region with expected typical Galactocentric distance of about 3 kpc. We use the spectra to search for emission-line central stars in the observed sample. Results: The distributions of the chemical abundances of the observed disk sample are generally indistinguishable from Galactic bulge and inner-disk PNe populations. The exceptions are possible differences in the He/H distribution, as compared to bulge PNe and Ne/Ar, as compared to the inner-disk PNe sample. The derived O/H ratios for the observed disk PNe fit to the concept of flattening of the chemical gradient in the inner parts of the Milky Way. Investigating the spectra, we found six new emission-line central stars comprising examples of all known types: WEL, VL, and [WR]. We confirm that these types represent three evolutionary unconnected forms of enhanced mass-loss in the central stars of PNe. We note on the problem of high ionisation PNe with nebular C IV emission that can mimic the presence of WEL central stars in 1D spectra. Based on observations made at the South African Astronomical Observatory.Appendices are available in electronic form at http://www.aanda.org

Górny, S. K.

2014-10-01

347

Using magnetic levitation to distinguish atomic-level differences in chemical composition of polymers, and to monitor chemical reactions on solid supports.  

PubMed

This communication describes a density-based method that uses magnetic levitation for monitoring solid-supported reactions and for distinguishing differences in chemical composition of polymers. The method is simple, rapid, and inexpensive and is similar to thin-layer chromatography (TLC; for solution-phase chemistry) in its potential for monitoring reactions in solid-phase chemistry. The technique involves levitating a sample of beads (taken from a reaction mixture) in a cuvette containing a paramagnetic solution (e.g., GdCl(3) dissolved in H(2)O) positioned between two NdFeB magnets. The vertical position at which the beads levitate corresponds to the density of the beads and correlates with the progress of a chemical reaction on a solid support. The method is particularly useful for monitoring the kinetics of reactions occurring on polymer beads. PMID:19063630

Mirica, Katherine A; Phillips, Scott T; Shevkoplyas, Sergey S; Whitesides, George M

2008-12-31

348

Morphology and Chemical composition of Atmospheric Particles over Semi-Arid region (Jaipur, Rajasthan) of India  

NASA Astrophysics Data System (ADS)

Uncertainties associated with the radiative forcing of atmospheric dust particles is highest, owing to lack of region-specific dust morphology (particle shape, size) and mineralogy (chemical composition) database, needed for modeling their optical properties (Mishra and Tripathi, 2008). To fill this gap for the Indian region, we collected atmospheric particles (with aerodynamic size <5um, PM5 and a few bulk particles; TSP) from seven sites of Jaipur and nearby locales (semi-arid region, in the vicinity of Thar Desert of Rajasthan) at varying altitude, during late winters of ca. 2012. PM5 particles were collected on Teflon filters (for bulk chemical analyses), while pure Tin substrates (~1×1 mm2) were used for investigating individual particle morphology. Using Scanning Electron Microscope equipped with Energy Dispersive X ray (SEM-EDX) facility at NPL, images of individual particles were recorded and the morphological parameters (e.g. Aspect ratio; AR, Circulatory parameter; CIR.) were retrieved following Okada et al. (2001), whereas chemical compositions of individual particles were determined by EDX and bulk samples by X ray fluorescence (XRF). The geometrical size distributions of atmospheric particles were generated for each site. Based on NIST (National Institute of Standard and Technology, USA) morphology database, the site-specific individual particle shapes reveal predominance of "Layered" (calcite and quartz rich), "Angular" structures (quartz rich) and "Flattened" particles over all the sites. Particles were found to be highly non-spherical with irregular shapes (CIR varying from 1 to 0.22 with median value ~0.76; AR varying from 1 to 5.4 with median value ~1.64). Noteworthy to mention, that unit values of AR and CIR represent spherical particles. Chemical analyses of PM5 particles revealed dominance of crustal elements e.g. Si, Al, Fe, Ca, Mg, in general. Particles over Kukas Hill (27.027° N, 75.919° E; ~800 MAGL) showed highest Fe mass fractions (~43%), i.e. a key element (in form of hematite; Fe2O3) for solar (visible) energy absorption and thus heating the atmosphere. The retrieved morphological parameters help to construct particle shape and number size distribution that are highly useful to reduce the uncertainty in radiative forcing of dust particles appreciably when combined with particle chemical composition as suggested by Kalashnikova and Sokolik (2004). References : Mishra, S. K., and S. N. Tripathi (2008), Modeling optical properties of mineral dust over the Indian Desert, J. Geophys. Res., 113, D23201, 19 PP., doi:10.1029/2008JD010048. Okada, K., J. Heintzenberg, K. Kai, and Y. Qin (2001), Shape of atmospheric mineral particles collected in three Chinese arid-regions, Geophys. Res. Lett., 28, 3123-3126 Kalashnikova OV, Sokolik IN. (2004) Modeling the radiative properties of nonspherical soil-derived mineral aerosols, J Quant Spectrosc Radiat Transfer, 87, 137-66.

Mishra, S. K.; Agnihotri, R.; Yadav, P.; Singh, S.; Tawale, J. S.; Rashmi, R.; Prasad, M.; Arya, B. C.; Mishra, N.

2012-12-01

349

Chemical composition of ferromanganese crusts in the world ocean: a review and comprehensive database  

USGS Publications Warehouse

A comprehensive database of chemical and mineralogical properties for ferromanganese crusts collected throughout the Atlantic, Pacific, and Indian Oceans, and has been assembled from published and unpublished sources which provide collection and analytical information for these samples. These crusts, their chemical compositions and natural distribution, have been a topic of interest to scientific research, as well as to industrial and military applications. Unlike abyssal ferromanganese nodules, which form in areas of low disturbance and high sediment accumulation, crusts have been found to contain three to five times more cobalt than these nodules, and can be found on harder, steeper substrates which can be too steep for permanent sediment accumulation. They have also been documented on seamounts and plateaus within the U.S. exclusive economic zone in both Pacific and Atlantic Oceans, and these are therefore of strategic importance to the United States Government, as well as to civilian mining and metallurgical industries. The data tables provided in this report have been digitized and previously uploaded to the National Oceanic and Atmospheric Administration National Geophysical Data Center in 1991 for online distribution, and were provided in plain text format. The 2014 update to the original U.S. Geological Survey open-file report published in 1989 provides these data tables in a slightly reformatted version to make them easier to ingest into geographic information system software, converted to shapefiles, and have completed metadata written and associated with them.

Manheim, Frank T.; Lane-Bostwick, Candice M.

1989-01-01

350

Effect of Chemical Composition on Enthalpy of Evaporation and Equilibrium Vapor Pressure  

E-print Network

Proceeding from the Clausius-Clapeyron equation, the relation is derived that establishes a correlation between the partial enthalpy of evaporation from binary solutions, concentrations of components, and equilibrium vapor pressures. The difference between enthalpies of evaporation of components from solutions and those from the pure liquids, D(DH), depends on the chemical nature and concentrations, X, of solutions. The effect of concentrations on D(DH) makes different appearances in ideal and non-ideal solutions, although, as a whole, D(DH) increases with the growth of concentration of the second component. A model is introduced, which considers D(DH) as the sum of energetic changes of three sequential stages: passage of molecules from the bulk liquid into the surface layer, exit of the molecules on the outer side of the interface, and the following desorption into the gas phase. In the framework of the model, the main contribution to enthalpy of evaporation comes from the processes in the surface layer. It is suggested that adsorption from solutions, which changes the chemical composition of the surface layer with respect to that of the bulk solution, determines, to great extent, the difference in the forms of the curves D(DH)=f(X) for ideal and non-ideal solutions.

Vladimir Kh. Dobruskin

2010-04-20

351

The effects of space radiation on a chemically modified graphite-epoxy composite material  

NASA Technical Reports Server (NTRS)

The effects of the space environment on the engineering properties and chemistry of a chemically modified T300/934 graphite-epoxy composite system are characterized. The material was subjected to 1.0 x 10 to the 10th power rads of 1.0 MeV electron irradiation under vacuum to simulate 30 years in geosynchronous earth orbit. Monotonic tension tests were performed at room temperature (75 F/24 C) and elevated temperature (250 F/121 C) on 4-ply unidirectional laminates. From these tests, inplane engineering and strength properties (E sub 1, E sub 2, Nu sub 12, G sub 12, X sub T, Y sub T) were determined. Cyclic tests were also performed to characterize energy dissipation changes due to irradiation and elevated temperature. Large diameter graphite fibers were tested to determine the effects of radiation on their stiffness and strength. No significant changes were observed. Dynamic-mechanical analysis demonstrated that the glass transition temperature was reduced by 50 F(28 C) after irradiation. Thermomechanical analysis showed the occurrence of volatile products generated upon heating of the irradiated material. The chemical modification of the epoxy did not aid in producing a material which was more radiation resistant than the standard T300/934 graphite-epoxy system. Irradiation was found to cause crosslinking and chain scission in the polymer. The latter produced low molecular weight products which plasticize the material at elevated temperatures and cause apparent material stiffening at low stresses at room temperature.

Reed, S. M.; Herakovich, C. T.; Sykes, G. F.

1986-01-01

352

Structure Chemical Composition And Reactivity Correlations during the In Situ Oxidation of 2-Propanol  

SciTech Connect

Unraveling the complex interaction between catalysts and reactants under operando conditions is a key step toward gaining fundamental insight in catalysis. We report the evolution of the structure and chemical composition of size-selected micellar Pt nanoparticles ({approx}1 nm) supported on nanocrystalline {gamma}-Al{sub 2}O{sub 3} during the catalytic oxidation of 2-propanol using X-ray absorption fine-structure spectroscopy. Platinum oxides were found to be the active species for the partial oxidation of 2-propanol (<140 C), while the complete oxidation (>140 C) is initially catalyzed by oxygen-covered metallic Pt nanoparticles, which were found to regrow a thin surface oxide layer above 200 C. The intermediate reaction regime, where the partial and complete oxidation pathways coexist, is characterized by the decomposition of the Pt oxide species due to the production of reducing intermediates and the blocking of O{sub 2} adsorption sites on the nanoparticle surface. The high catalytic activity and low onset reaction temperature displayed by our small Pt particles for the oxidation of 2-propanol is attributed to the large amount of edge and corner sites available, which facilitate the formation of reactive surface oxides. Our findings highlight the decisive role of the nanoparticle structure and chemical state in oxidation catalytic reactions.

K Paredis; L Ono; S Mostafa; L Li; Z Zhang; J Yang; L Barrio; A Frenkel; B Roldan Cuenya

2011-12-31

353

Aerosols near by a coal fired thermal power plant: chemical composition and toxic evaluation.  

PubMed

Industrial processes discharge fine particulates containing organic as well as inorganic compounds into the atmosphere which are known to induce damage to cell and DNA, both in vitro and in vivo. Source and area specific studies with respect to the chemical composition, size and shape of the particles, and toxicity evaluations are very much limited. This study aims to investigate the trace elements associated with the aerosol particles distributed near to a coal burning thermal power plant and to evaluate their toxicity through Comet assay. PM(10) (particles determined by mass passing an inlet with a 50% cut-off efficiency having a 10-microm aerodynamic diameter) samples were collected using respirable dust samplers. Twelve elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Se, Hg, and As) were analyzed using ICP-AES. Comet assay was done with the extracts of aerosols in phosphate buffered saline (PBS). Results show that Fe and Zn were found to be the predominant elements along with traces of other analyzed elements. Spherical shaped ultrafine particles of <1 microm aerodynamic diameter were detected through scanning electron microscope. PM(10) particles near to the coal burning power plant produced comets indicating their potential to induce DNA damage. DNA damage property is found to be depending upon the chemical characteristics of the components associated with the particles besides the physical properties such as size and shape. PMID:19264341

Jayasekher, T

2009-06-01

354

Chemical composition and in vitro antifungal activity screening of the Allium ursinum L. (Liliaceae).  

PubMed

The objective of the study was to summarize the methods for isolating and identifying natural sulfur compounds from Allium ursinum (ramson) and to discuss the active constituents with regard to antifungal action. Using chromatographic techniques, the active constituents were isolated and subsequently identified. Analyses by high-performance liquid chromatography (HPLC) suggested that these compounds were sulfur constituents, with a characteristic absorbance at 250 nm. Gas chromatography-mass spectrometry (GC-MS) analyses allowed the chemical structures of the isolated constituents to be postulated. We adopted the same methods to identify the health-giving profiling of ramsons and the effects are thought to be primarily derived from the presence and breakdown of the alk(en)ylcysteine sulphoxide, alliin and its subsequent breakdown to allicin (sulfur-compounds of ramson) in connection with antifungal action. The aim of the study was the characterization of the chemical composition of ramsons and the testing of the action of the in vitro extracts, on different strains of Candida albicans. The main goal was to highlight the most efficient extracts of Allium ursinum that can provide long-term antifungal activity without remissions. The extracts from Allium ursinum plants, inhibited growth of Candida spp. cells at concentrations ranging from 0.5 to 4.0 mg/mL, while that of adherent cells at concentrations ranging from 1.0 to > 4.0 mg/mL, depending on the yeast and plant species. PMID:22408399

Bagiu, Radu Vasile; Vlaicu, Brigitha; Butnariu, Monica

2012-01-01

355

Chemical composition of Eucalyptus spp. essential oils and their insecticidal effects on Lutzomyia longipalpis.  

PubMed

The chemical composition of essential oils from three species of plants belonging to the Eucalyptus genus was determined and, their insecticidal effects on egg, larva and adult phases of Lutzomyia longipalpis were assessed. The insects were collected in the municipality of Sobral in the State of Ceará, Brazil. Five treatments with different concentrations were performed along with two negative controls, distilled water and Tween 80 (3%), and a positive control, cypermethrin (0.196mg/ml). The tests were carried out in plastic pots internally coated with sterile plaster and filled with a substrate made of rabbit feces and crushed cassava leaves. The eggs, larvae and adults were sprayed with the oils. The hatched larvae were counted for 10 consecutive days and observed until pupation. Insect mortality was observed after 24, 48 and 72h. E. staigeriana oil was the most effective on all three phases of the insect, followed by E. citriodora and E. globulus oils, respectively. The major constituents of the oils were Z-citral and alpha-citral (E. staigeriana), citronellal (E. citriodora) and 1,8-cineole (E. globulus). The Eucalyptus essential oils constitute alternative natural products for the control of L. longipalpis since the median effective concentration (EC(50)) values revealed relevant action as compared with other natural products, some of their chemical constituents are already known for their insecticidal activity and these oils are produced in commercial scale in Brazil. PMID:19896276

Maciel, M V; Morais, S M; Bevilaqua, C M L; Silva, R A; Barros, R S; Sousa, R N; Sousa, L C; Brito, E S; Souza-Neto, M A

2010-01-20

356

Chemical Composition and in Vitro Antifungal Activity Screening of the Allium ursinum L. (Liliaceae)  

PubMed Central

The objective of the study was to summarize the methods for isolating and identifying natural sulfur compounds from Allium ursinum (ramson) and to discuss the active constituents with regard to antifungal action. Using chromatographic techniques, the active constituents were isolated and subsequently identified. Analyses by high-performance liquid chromatography (HPLC) suggested that these compounds were sulfur constituents, with a characteristic absorbance at 250 nm. Gas chromatography-mass spectrometry (GC-MS) analyses allowed the chemical structures of the isolated constituents to be postulated. We adopted the same methods to identify the health-giving profiling of ramsons and the effects are thought to be primarily derived from the presence and breakdown of the alk(en)ylcysteine sulphoxide, alliin and its subsequent breakdown to allicin (sulfur-compounds of ramson) in connection with antifungal action. The aim of the study was the characterization of the chemical composition of ramsons and the testing of the action of the in vitro extracts, on different strains of Candida albicans. The main goal was to highlight the most efficient extracts of Allium ursinum that can provide long-term antifungal activity without remissions. The extracts from Allium ursinum plants, inhibited growth of Candida spp. cells at concentrations ranging from 0.5 to 4.0 mg/mL, while that of adherent cells at concentrations ranging from 1.0 to > 4.0 mg/mL, depending on the yeast and plant species. PMID:22408399

Bagiu, Radu Vasile; Vlaicu, Brigitha; Butnariu, Monica

2012-01-01

357

New chemical determinations of zinc in basalts, and rocks of similar composition  

USGS Publications Warehouse

New determinations of zinc in 124 basalts by the chemical method described (Huff-Man et al. 1963) are reported. Average zinc values, in per cent, for basalts from diverse regions are as follows: Idaho, 28 samples, 0.013; Hawaii, 33 samples, 0.010; Connecticut, 27 samples, 0.0090; Oregon, 17 samples, 0.0081; California, 8 samples, 0.0071; and New Mexico, 11 samples, 0.0086; average, all samples, 0.0099 per cent zinc. A plot of differentiation indicator ratios calculated from the conventional rock analyses, CaO/(Na2O + K2O) as the ordinate and SiO2/MgO as the abscissa, was used to select, from different localities, samples essentially the same in chemical composition that were to be used for comparisons of zinc and other minor elements. Zinc correlates with MnO and with total iron as FeO. An inverse relationship found for zinc and manganese is related to the total iron content of the basalts. Thus for a given iron concentration as zinc increases, manganese decreases and vice versa. Ratios of zinc, the common denominator, to 11 other minor elements determined spectro-graphically show correlations with cobalt, gallium, scandium, yttrium, and zirconium. ?? 1963.

Rader, L.F.; Swadley, W.C.; Huffman, C., Jr.; Lipp, H.H.

1963-01-01

358

Determining the chemical composition of cloud condensation nuclei. Third progress report  

SciTech Connect

This third progress report describes the status of our efforts to develop the instrumentation to collect cloud condensation nuclei (CCN) in amounts sufficient for chemical analysis. During the fall of 1992 we started collecting filter samples of CCN with the laboratory version of the apparatus at Rolla -MO. The mobile version of the apparatus is in the latter stages of construction. This report includes a fairly rigorous discussion of the operation of the CCN sampling system. A statistical model of the operation of the system is presented to show the ability of the system to collect CCN in the two different size ranges for which we plan to determine the chemical composition. A question is raised by the model results about the operation of one of the virtual impactors. It appears to pass a small percent of particles larger than its cut-point that has the potential of contaminating the smallest CCN sample with larger CCN material. Further tests are necessary, but it may be necessary to redesign that impactor. The appendices of the report show pictures of both the laboratory version and the mobile version of the CCN sampling system. The major hardware has been completed, and the mobile version will be in operation within a few weeks.

Williams, A.L.; Rothert, J.E.; McClure, K.E. [Illinois State Water Survey, Champaign, IL (United States); Alofs, D.J.; Hagen, D.E.; Schmitt, J.; White, D.R.; Hopkins, A.R.; Trueblood, M.B. [Missouri Univ., Rolla, MO (United States). Cloud and Aerosol Science Lab.

1992-12-01

359

Chemical composition and antimicrobial activity of essential oils of Ocimum canum Sims. and Ocimum selloi Benth.  

PubMed

This work describes the chemical composition and antimicrobial activity of the volatile oils of Ocimum canum and Ocimum selloi, both occurring in Jequié/BA, northeastern Brazil. The plants were collected in the winter/2005 and summer/2006, the oils extracted by steam distillation and further analyzed by GC-MS. A total of 30 and 31 compounds was identified from the oils of O. selloi and O. canum, respectively. It was observed that the oil content of O. canum showed variation during the seasons, while the oils of O. selloi did not. Methylchavicol and linalool were the main chemical components found in the aerial parts and leaves of O. canum. This finding permitted to characterize this specimen as a new chemotype of O. canum. Regarding the aerial parts of O. selloi, eugenol, 1,8-cineole, transcaryophyllene and linalool were identified as their major components. All extracted oils from the aerial parts showed biological activity against gram-positive cocci – Staphylococcus aureus ATCC 25923 – but only the O. canum one showed activity against gram-negative bacilli – Escherichia coli ATCC 25922. PMID:21969960

Nascimento, Jeferson C; Barbosa, Luiz C A; Paula, Vanderlucia F; David, Jorge M; Fontana, Renato; Silva, Luiz A M; França, Robson S

2011-09-01

360

The surface chemical composition of lunar samples and its significance for optical properties  

NASA Technical Reports Server (NTRS)

The surface Fe, Ti, Ca, and Si concentrations in a variety of soil and rock samples from all the Apollo sites are determined using an Auger spectrometer plus a single-pass cylindrical-mirror analyzer with a standard 15-stage BeCu electron multiplier. It is found that there are no great differences between the surface and bulk concentrations of any of the four elements in the rock samples, but the surface Fe and Ti concentrations in soil samples are higher than the bulk concentrations. Results are also reported for solar-wind simulation experiments in which a pulverized rock sample was bombarded with 2-keV alpha-particles corresponding to about a 30,000-yr dose of the solar-wind proton component. These results indicate that the chemical change induced on the surface of a rock powder by positive-ion bombardment is similar to the change from bulk to surface chemical composition in lunar soil samples. A clear correlation is observed between the surface Fe concentration and albedo of the soil samples.

Gold, T.; Bilson, E.; Baron, R. L.

1976-01-01

361

Correlating Titania Morphology and Chemical Composition with Dye-sensitized Solar Cell Performance  

SciTech Connect

We have investigated the use of various morphologies, including nanoparticles, nanowires, and sea-urchins of TiO{sub 2} as the semiconducting material used as components of dye-sensitized solar cells (DSSCs). Analysis of the solar cells under AM 1.5 solar irradiation reveals the superior performance of hydrothermally derived nanoparticles, by comparison with two readily available commercial nanoparticle materials, within the DSSC architecture. The sub-structural morphology of films of these nanostructured materials has been directly characterized using SEM and indirectly probed using dye desorption. Furthermore, the surfaces of these nanomaterials were studied using TEM in order to visualize their structure, prior to their application within DSSCs. Surface areas of the materials have been quantitatively analyzed by collecting BET adsorption and dye desorption data. Additional investigation using open circuit voltage decay measurements reveals the efficiency of electron conduction through each TiO{sub 2} material. Moreover, the utilization of various chemically distinctive titanate materials within the DSSCs has also been investigated, demonstrating the deficiencies of using these particular chemical compositions within traditional DSSCs.

Santulli, A.C.; Wong, S.; Koenigsmann, C.; Tiano, A.L., DeRosa, D.

2011-04-20

362

Submicron NE Atlantic marine aerosol chemical composition and abundance: Seasonal trends and air mass categorization  

NASA Astrophysics Data System (ADS)

years of continuous Aerosol Mass Spectrometry measurements at the Mace Head Global Atmosphere Watch research station revealed seasonal patterns in the chemical composition of submicron NE Atlantic marine aerosol as well as distinct chemical signatures associated with marine air masses of different origin (i.e., polar, Arctic, or tropical). Concentrations of secondary inorganic aerosol species and both primary and secondary organic compounds were closely related to oceanic biological activity and ranged from low median mass concentrations during winter to high median values during summer as follows: 0.025-0.9 µg m-3 for nonsea-salt sulfate (nss-sulfate), 0.025-0.4 µg m-3 for organic matter, 0-0.09 µg m-3 for methanesulfonic acid (MSA). Sea-salt concentrations illustrated an opposite pattern with the highest median value being observed during winter (0.74 µg m-3) and lowest during summer (0.08 µg m-3). Maritime polar air masses typically featured the highest concentrations of sea salt and marine organics, particularly enhanced under primary organic plumes during periods of high biological activity. MSA and nss-sulfate were more prominent in tropical air masses. The oxidation of organic matter increased with increasing ozone concentration and wintertime (low biological activity) organic matter displayed a different fragmentation pattern from that of summertime organic compounds.

Ovadnevaite, Jurgita; Ceburnis, Darius; Leinert, Stephan; Dall'Osto, Manuel; Canagaratna, Manjula; O'Doherty, Simon; Berresheim, Harald; O'Dowd, Colin

2014-10-01

363

Chemically produced nanostructured ODS-lanthanum oxide-tungsten composites sintered by spark plasma  

NASA Astrophysics Data System (ADS)

High purity W and W-0.9La 2O 3 (wt.%) nanopowders were produced by a wet chemical route. The precursor was prepared by the reaction of ammonium paratungstate (APT) with lanthanum salt in aqueous solutions. High resolution electron microscopy investigations revealed that the tungstate particles were coated with oxide precipitates. The precursor powder was reduced to tungsten metal with dispersed lanthanum oxide. Powders were consolidated by spark plasma sintering (SPS) at 1300 and 1400 °C to suppress grain growth during sintering. The final grain size relates to the SPS conditions, i.e. temperature and heating rate, regardless of the starting powder particle size. Scanning electron microscopy revealed that oxide phases were mainly accumulated at grain boundaries while the tungsten matrix constituted of nanosized sub-grains. The transmission electron microscopy revealed that the tungsten grains consist of micron-scale grains and finer sub-grains. EDX analysis confirmed the presence of W in dispersed oxide phases with varying chemical composition, which evidenced the presence of complex oxide phases (W-O-La) in the sintered metals.

Yar, Mazher Ahmed; Wahlberg, Sverker; Bergqvist, Hans; Salem, Hanadi G.; Johnsson, Mats; Muhammed, Mamoun

2011-01-01

364

Dissolution of Th1-xUxO2: Effects of chemical composition and microstructure  

NASA Astrophysics Data System (ADS)

The dissolution of Th1-xUxO2 solid solutions was studied by varying independently several parameters such as chemical composition, leachate acidity, leaching temperature, firing temperature, and densification state. The chemical durability of the samples was significantly affected by the uranium mole loading probably due to the oxidation of tetravalent uranium into uranyl during the dissolution process. The influence of nitric acid concentration and temperature also showed that the behavior of Th1-xUxO2 solid solutions with higher uranium incorporation fractions (x = 0.52, 0.75 and 1) differed significantly from that of Th0.84U0.16O2. Strong modifications of the dissolution mechanism occurring at the solid/liquid interface for the higher uranium loadings could explain this difference. It could result in the existence of the fast oxidation of U(IV) to U(VI) at the solid/solution interface then of the detachment of activated complexes formed with U(VI). Furthermore, initial normalized dissolution rate slightly depended on the elimination of crystal defects for firing temperatures below 900 °C but was almost independent of the crystallite size (T ? 900 °C). Finally, dissolution tests on sintered Th0.84U0.16O2 samples showed that RL(Th) values decreased by an order of magnitude when the relative density increased from 79% to 89%.

Claparede, Laurent; Tocino, Florent; Szenknect, Stéphanie; Mesbah, Adel; Clavier, Nicolas; Moisy, Philippe; Dacheux, Nicolas

2015-02-01

365

Particle emissions from a marine engine: chemical composition and aromatic emission profiles under various operating conditions.  

PubMed

The chemical composition of particulate matter (PM) emissions from a medium-speed four-stroke marine engine, operated on both heavy fuel oil (HFO) and distillate fuel (DF), was studied under various operating conditions. PM emission factors for organic matter, elemental carbon (soot), inorganic species and a variety of organic compounds were determined. In addition, the molecular composition of aromatic organic matter was analyzed using a novel coupling of a thermal-optical carbon analyzer with a resonance-enhanced multiphoton ionization (REMPI) mass spectrometer. The polycyclic aromatic hydrocarbons (PAHs) were predominantly present in an alkylated form, and the composition of the aromatic organic matter in emissions clearly resembled that of fuel. The emissions of species known to be hazardous to health (PAH, Oxy-PAH, N-PAH, transition metals) were significantly higher from HFO than from DF operation, at all engine loads. In contrast, DF usage generated higher elemental carbon emissions than HFO at typical load points (50% and 75%) for marine operation. Thus, according to this study, the sulfur emission regulations that force the usage of low-sulfur distillate fuels will also substantially decrease the emissions of currently unregulated hazardous species. However, the emissions of soot may even increase if the fuel injection system is optimized for HFO operation. PMID:25202837

Sippula, O; Stengel, B; Sklorz, M; Streibel, T; Rabe, R; Orasche, J; Lintelmann, J; Michalke, B; Abbaszade, G; Radischat, C; Gröger, T; Schnelle-Kreis, J; Harndorf, H; Zimmermann, R

2014-10-01

366

Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors  

NASA Technical Reports Server (NTRS)

Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.

Ryan, M. A.; Lewis, N. S.

2001-01-01

367

CHEMICAL COMPOSITION OF COMET C/2007 N3 (LULIN): ANOTHER ''ATYPICAL'' COMET  

SciTech Connect

We measured the volatile chemical composition of comet C/2007 N3 (Lulin) on three dates from 2009 January 30 to February 1 using NIRSPEC, the high-resolution ({lambda}/{Delta}{lambda} Almost-Equal-To 25,000), long-slit echelle spectrograph at Keck 2. We sampled nine primary (parent) volatile species (H{sub 2}O, C{sub 2}H{sub 6}, CH{sub 3}OH, H{sub 2}CO, CH{sub 4}, HCN, C{sub 2}H{sub 2}, NH{sub 3}, CO) and two product species (OH* and NH{sub 2}). We also report upper limits for HDO and CH{sub 3}D. C/2007 N3 (Lulin) displayed an unusual composition when compared to other comets. Based on comets measured to date, CH{sub 4} and C{sub 2}H{sub 6} exhibited 'normal' abundances relative to water, CO and HCN were only moderately depleted, C{sub 2}H{sub 2} and H{sub 2}CO were more severely depleted, and CH{sub 3}OH was significantly enriched. Comet C/2007 N3 (Lulin) is another important and unusual addition to the growing population of comets with measured parent volatile compositions, illustrating that these studies have not yet reached the level where new observations simply add another sample to a population with well-established statistics.

Gibb, Erika L.; Sudholt, Emily [Department of Physics and Astronomy, University of Missouri-St. Louis, St. Louis, MO 63121 (United States); Bonev, Boncho P.; Villanueva, Geronimo; Radeva, Yana [Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); DiSanti, Michael A.; Mumma, Michael J., E-mail: gibbe@umsl.edu [Goddard Center for Astrobiology, Solar System Exploration Division, NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771 (United States)

2012-05-10

368

Formation of anodic layers on InAs (111)III. Study of the chemical composition  

SciTech Connect

The chemical composition of {approx}20-nm-thick anodic layers grown on InAs (111)III in alkaline and acid electrolytes containing or not containing NH{sub 4}F is studied by X-ray photoelectron spectroscopy. It is shown that the composition of fluorinated layers is controlled by the relation between the concentrations of fluorine and hydroxide ions in the electrolyte and by diffusion processes in the growing layer. Fluorine accumulates at the (anodic layer)/InAs interface. Oxidation of InAs in an acid electrolyte with a low oxygen content and a high NH{sub 4}F content brings about the formation of anodic layers with a high content of fluorine and elemental arsenic and the formation of an oxygen-free InF{sub x}/InAs interface. Fluorinated layers grown in an alkaline electrolyte with a high content of O{sup 2-} and/or OH{sup -} groups contain approximately three times less fluorine and consist of indium and arsenic oxyfluorides. No distinction between the compositions of the layers grown in both types of fluorine-free electrolytes is established.

Valisheva, N. A., E-mail: valisheva@thermo.isp.nsc.ru; Tereshchenko, O. E. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Prosvirin, I. P.; Kalinkin, A. V. [Russian Academy of Sciences, Boreskov Institute of Catalysis, Siberian Branch (Russian Federation); Goljashov, V. A. [Novosibirsk State University (Russian Federation); Levtzova, T. A. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Bukhtiyarov, V. I. [Russian Academy of Sciences, Boreskov Institute of Catalysis, Siberian Branch (Russian Federation)

2012-04-15

369

Chemical composition of 13 commercial soybean samples and their antioxidant and anti-inflammatory properties.  

PubMed

A total of 13 commercial soybean samples were investigated and compared for their tocopherol and carotenoid compositions, fatty acid profile, total phenolic content (TPC), isoflavone and sterol compositions, and free radical scavenging properties. Free radical scavenging activities were estimated against peroxyl, hydroxyl, and ABTS(•)?(+) radicals. The commercial soybean samples differed in their chemical compositions and health properties. Among the tested samples, CN-DB soybean showed the highest TPC and antioxidant activities and the greatest amount of total isoflavones and lutein and tocopherol contents. In addition, four of the soybean samples were further tested for their potential anti-inflammatory activity. The four samples behaved differently in suppressing the IL-1?, IL-6, and COX-2 mRNA expressions, suggesting their different potential of anti-inflammatory activities. The results from this study suggested a need of improved quality control and measurement system to better reflect the health properties of commercial soybeans for general consumers and food manufacturers to improve the use of this important food ingredient. PMID:22978480

Zhang, Xiaowei; Gao, Boyan; Shi, Haiming; Slavin, Margaret; Huang, Haiqiu; Whent, Monica; Sheng, Yi; Yu, Liangli Lucy

2012-10-10

370

Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors.  

PubMed

Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article. PMID:11570422

Ryan, M A; Lewis, N S

2001-01-01

371

Verification of Chemical Composition of Commercially Available Propolis Extracts by Gas Chromatography-Mass Spectrometry Analysis.  

PubMed

Abstract Propolis is a resin that is collected by honeybees from various plant sources. Due to its pharmacological properties, it is used in commercial production of nutritional supplements in pharmaceutical industry. In this study, gas chromatography-mass spectrometry was applied for quality control analysis of the three commercial specimens containing aqueous-alcoholic extracts of bee propolis. More than 230 constituents were detected in analyzed products, including flavonoids, chalcones, cinnamic acids and their esters, phenylpropenoid glycerides, and phenylpropenoid sesquiterpenoids. An allergenic benzyl cinnamate ester was also identified in all tested samples. This analytical method allows to evaluate biological activity and potential allergenic components of bee glue simultaneously. Studies on chemical composition of propolis samples may provide new approach to quality and safety control analysis in production of propolis supplementary specimens. PMID:25198412

Czy?ewska, Urszula; Kono?czuk, Joanna; Teul, Joanna; Dr?gowski, Pawe?; Pawlak-Morka, Renata; Sura?y?ski, Arkadiusz; Miltyk, Wojciech

2014-09-01

372

Amino acids content and basic chemical composition of roe deer (Capreolus capreolus L.) meat.  

PubMed

The aim of this study was to determine the chemical composition of roe deer meat considering the animals' sex and age and to estimate the content of amino acids in the meat from two selected groups of the animals, i.e. 2-3-year-old males and females. A further goal was to assess the biological value of proteins as compared to the FAO standard. The study has revealed that in proteins from the roe deer muscle tissue the content of exogenous amino acids (in g/100g) is higher by 20-30% on average comparing to the level of amino acids, in the FAO/WHO (1973) standard protein. Among the endogenous amino acids, the highest (in g/100 g of protein) and the lowest concentrations were found for glutamic acid and proline, respectively. The research has also shown that roe deer meat possesses a high content of protein and a relatively low content of fat. PMID:23390753

Cygan-Szczegielniak, D; Janicki, B

2012-01-01

373

How Soil Organic Matter Composition Controls Hexachlorobenzene-Soil-Interactions: Adsorption Isotherms and Quantum Chemical Modelling  

E-print Network

Hazardous persistent organic pollutants (POPs) interact in soil with the soil organic matter (SOM) but this interaction is insufficiently understood at the molecular level. We investigated the adsorption of hexachlorobenzene (HCB) on soil samples with systematically modified SOM. These samples included the original soil, the soil modified by adding a hot water extract (HWE) fraction (soil+3 HWE and soil+6 HWE), and the pyrolyzed soil. The SOM contents increased in the order pyrolyzed soil soil soil+3 HWE soil+6 HWE. For the latter three samples this order was also valid for the HCB adsorption. The pyrolyzed soil adsorbed more HCB than the other samples at low initial concentrations, but at higher concentrations the HCB adsorption became weaker than in the samples with HWE addition. This adsorption behaviour combined with the differences in the chemical composition between the soil samples suggested that alkylated aromatic, phenol, and lignin monomer compounds contributed most to the HC...

Ahmed, Ashour; Kühn, Oliver

2013-01-01

374

The essential oil of Populus balsamifera buds: its chemical composition and cytotoxic activity.  

PubMed

The chemical composition of Populus balsamifera essential oils obtained from spring buds, fall buds, and young leaves were determined by GC and GC-MS analyses. The major constituent, (+)-alpha-bisabolol, a rare sesquiterpene, was isolated from spring oil using reverse-phase preparative HPLC. The cytotoxic activity of balsam poplar oils and isolated (+)-alpha-bisabolol was assessed in vitro against human lung carcinoma (A549) and colorectal adenocarcinoma (DLD-1) cell lines. Essential oils were cytotoxic with IC50 ranging from 35 to 50 microg/mL. (+)-alpha-Bisabolol exhibited pronounced activity (IC50 14 microg/mL) against both cancer cell lines. It also exhibited interesting cytotoxic activity (IC50 23 microg/mL) against human glioma (U251), higher than the one observed for (-)-alpha-bisabolol (IC50 34 microg/mL), which is known for its apoptosis-inducing effect against glioma cells. PMID:24689304

Piochon-Gauthier, Marianne; Legault, Jean; Sylvestre, Muriel; Pichette, André

2014-02-01

375

Comparison of chemical composition and antibacterial activity of lavender varieties from Poland.  

PubMed

The aim of the study was comparing the chemical composition of the essential oils from five varieties of lavender (Lavandula angustifolia L.), and its biological activity against two pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. In the comparison we included the following varieties: 'Munstead', 'Munstead Strain', 'Lavender Lady', 'Ellegance Purple' and 'Blue River'. Selected varieties of lavender (L. angustifolia) are characterised by exactly the same main compounds with only variations in the percentage of content. The primary components of the essential oils were: linalool (23.9-15.8%), linalyl anthranilate (12.3-1.6%), 1-terpinen-4-ol (9.7-5.5%), p-menth-1-en-8-ol (7.9-4.0%) and linalool oxide (4.7-1.1%). From the essential oils that were tested, the 'Blue River' and 'Munstead' varieties have the greatest antibacterial activity against S. aureus and P. aeruginosa. PMID:22989360

Adaszy?ska, M; Swarcewicz, M; Dzi?cio?, M; Dobrowolska, A

2013-01-01

376

Spectral Analysis by XANES Reveals that GPNMB Influences the Chemical Composition of Intact Melanosomes  

SciTech Connect

GPNMB is a unique melanosomal protein. Unlike many melanosomal proteins, GPNMB has not been associated with any forms of albinism, and it is unclear whether GPNMB has any direct influence on melanosomes. Here, melanosomes from congenic strains of C57BL/6J mice mutant for Gpnmb are compared to strain-matched controls using standard transmission electron microscopy and synchrotron-based X-ray absorption near-edge structure analysis (XANES). Whereas electron microscopy did not detect any ultrastructural changes in melanosomes lacking functional GPNMB, XANES uncovered multiple spectral phenotypes. These results directly demonstrate that GPNMB influences the chemical composition of melanosomes and more broadly illustrate the potential for using genetic approaches in combination with nano-imaging technologies to study organelle biology.

T Haraszti; C Trantow; A Hedberg-Buenz; M Grunze; M Anderson

2011-12-31

377

[Chemical composition of fresh bee pollen collected in the Misintá páramo from the Venezuelan Andes].  

PubMed

Venezuelan bee pollen has not been characterized, and marketing is not regulated. Pollen is consumed for apitherapeutical purposes for its nutritional and medicinal properties. This product of the hive is the most popular after honey; therefore it is necessary to characterize and to value it to initiate a database to support the proposal of a norm for bee pollen quality control. Samples of bee pollen collected by bees in the Misintá páramo of Mérida state were characterized accoridng to the chemical composition (moisture, ash, fat, pH, proteins) of four color fractions (yellow, orange, ochre, green). Yellow pollen was the most frequent fraction, with 2.18 g ash/100 g, 5.37 g ether extract/100 g, 14.88 g moisture/100 g, and 37.32 g proteins/100 g. PMID:19368304

Vit, Patricia; Santiago, B

2008-12-01

378

Chemical composition of essential oils of Grindelia squarrosa and G. hirsutula.  

PubMed

The essential oils of Grindelia squarrosa (Pursh) Dunal and G. hirsutula Hook. & Am. cultivated in Romania were isolated by hydrodistillation. The essential oils were analyzed by a combination of GC-FID and GC-MS. The identification of the constituents was achieved from their retention indices and comparison of their MS data with computer library database and literature data. The fifty-six identified constituents accounted for 72.1-81.3% of the oils. The oils were found to contain a-pinene, beta-pinene, limonene, borneol, bornyl acetate and germacrene D as main constituents. The oils obtained from the two species showed small differences in chemical composition. However, menthol, menthone and pulegone were detected only in the essential oil of G. hirsutula. PMID:24868887

Veres, Katalin; Roza, Orsolya; Laczkó-Zöld, Eszter; Hohmann, Judit

2014-04-01

379

Ion Composition near Enceladus during Cassini Flybys: Measurements and Chemical Model  

NASA Astrophysics Data System (ADS)

The Cassini spacecraft has flown by Saturn’s moon Enceladus several times, with the most recent two during a few weeks prior to this meeting. The surprising discovery of the jets of water/ice from the southern hemisphere of this moon has stimulated considerable discussion regarding the possible nature and especially temperature of the internal reservoir for these jets. A possible explanation that has been suggested for the apparently liquid water internal to such a cold, icy body involves the possible presence of small amounts of species such as ammonia that would affect the melting point. Measurements during previous flybys have hinted at the existence of such species. We have been analyzing the ion composition data from the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer obtained during the recent Enceladus flybys and comparing the results with those of a chemical network model (Boice, this session). In addition to the ubiquitous water group ions we find nitrogen and some of its hydrides.

Goldstein, R.; Boice, D. C.; Reisenfeld, D. B.; Tokar, R. L.; Young, D. T.

2009-12-01

380

Ugba, the fermented African oilbean seeds; its production, chemical composition, preservation, safety and health benefits.  

PubMed

Ugba is the Ibo name of the fermented African Oilbean seeds (Pentaclethra macrophylla, Benth). It is a traditional food condiment generally produced by natural (local) fermentation in homes as a small family business. It is an important and cheap source of protein for people whose staple foods are deficient in proteins. It is also eaten as a delicacy and used as flavouring for soup. This write up aims to review all published studies on ugba in the direction of the various methods used in the production, the chemical composition of the seeds, the microorganisms involved and the biochemical changes that occur during fermentation and optimization of the fermentation. The nutritional and food values, toxicological properties, health promoting potentials, microbiological safety as well as the storage and preservation have also been highlighted. PMID:21848073

Ogueke, C C; Nwosu, J N; Owuamanam, C I; Iwouno, J N

2010-05-15

381

Chemical composition and biological activities of the essential oils from two Pereskia species grown in Brazil.  

PubMed

The chemical composition of the essential oils of Pereskia aculeata Mill. and P. grandifolia Haw. (Cactaceae), grown in Brazil, was studied by means of GC and GC-MS. In all, 37 compounds were identified, 30 for P. aculeata and 15 for P. grandifolia. Oxygenated diterpenes are the main constituents, both in the oil ofP. grandifolia (55.5%) and in that ofP. aculeata (29.4%). The essential oils were evaluated for their in vitro phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Sinapis arvensis L., and Phalaris canariensis L. seeds. The essential oil of P. grandifolia, at all doses tested, significantly inhibited the radicle elongation of R. sativus. Moreover, the antimicrobial activity of the essential oils was assayed against ten bacterial strains. The essential oils showed weak inhibitory activity against the Gram-positive pathogens. PMID:25632490

Souza, Lucéia Fatima; De Barros, Ingrid Bergman Inchausti; Mancini, Emilia; De Martino, Laura; Scandolera, Elia; De Feo, Vincenzo

2014-12-01

382

Chemical composition and biological activities of the essential oil from Anredera cordifolia grown in Brazil.  

PubMed

The chemical composition of the essential oil of Anredera cordifolia (Ten.) Steenis (Basellaceae), grown in Brazil, was studied by means of GC and GC-MS analysis. In all, 19 compounds were identified, accounting for 91.6% of the total oil; hydrocarbons were the main constituents (67.7%). The essential oil was evaluated for its in vitro potential phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Sinapis arvensis L., and Phalaris canariensis L. seeds. At 1.25 microg/mL and 0.625 microg/mL, the oil significantly promoted the germination of S. arvensis. Moreover, the antimicrobial activity of the essential oil was assayed against ten bacterial strains. The essential oil showed a weak inhibitory activity against the Gram-positive pathogens. PMID:25230514

Souza, Lucéia Fátima; de Barros, Ingrid Bergman Inchausti; Mancini, Emilia; De Martino, Laura; Scandolera, Elia; De Feo, Vincenzo

2014-07-01

383

Chemical composition of vegetation along urbanisation gradients in two European cities.  

PubMed

Accumulation of particulate matter (PM) and metals on leaves of three deciduous woody species was studied along urbanisation gradients in Stavanger and Warsaw. Differences between rural and urban sites explained most of the observed variation in leaf chemistry, followed by differences between regions. Highest leaf accumulation of elements was found in Warsaw, but also composition of elements differed between the cities. Overall, species showed similar patterns of element accumulation, but differed in accumulation of specific elements. These differences could in part be explained by differences in epicuticular waxes and PM accumulation. Expected source of elements and their chemical characteristics did not explain the observed accumulation patterns. A better differentiation between elements taken up from soil and air would be required for his. Species specific accumulation of elements has to be taken into consideration using leaf samples for biomonitoring. PMID:25590129

Sæbø, A; Hanslin, H M; Torp, T; Lierhagen, S; Gawronska, H; Dzierzanowski, K; Gawronski, S

2015-03-01

384

Chemical composition and in vitro cytotoxic, genotoxic effects of essential oil from Urtica dioica L.  

PubMed

The aim of this study was to determine the chemical composition of Urtica dioica essential oil, and to evaluate its cytotoxic and genotoxic effects, using cytogenetic tests such as the cytokinesis-block micronucleus assay and chromosomal aberration analysis in human lymphocyte cultures in vitro. GC-MS analysis of U. dioica essential oil identified 43 compounds, representing 95.8% of the oil. GC and GC-MS analysis of the essential oil of U. dioica revealed that carvacrol (38.2%), carvone (9.0%), naphthalene (8.9%), (E)-anethol (4.7%), hexahydrofarnesyl acetone (3.0%), (E)-geranyl acetone (2.9%), (E)-?-ionone (2.8%) and phytol (2.7%) are the main components, comprising 72.2% of the oil. A significant correlation was found between the concentration of essential oil and the following: chromosomal aberrations, micronuclei frequency, apoptotic cells, necrotic cells, and binucleated cells. PMID:22310841

Gül, Süleyman; Demirci, Betül; Ba?er, Kemal Hüsnü Can; Akpulat, H A?kin; Aksu, Pinar

2012-05-01

385

General method and thermodynamic tables for computation of equilibrium composition and temperature of chemical reactions  

NASA Technical Reports Server (NTRS)

A rapidly convergent successive approximation process is described that simultaneously determines both composition and temperature resulting from a chemical reaction. This method is suitable for use with any set of reactants over the complete range of mixture ratios as long as the products of reaction are ideal gases. An approximate treatment of limited amounts of liquids and solids is also included. This method is particularly suited to problems having a large number of products of reaction and to problems that require determination of such properties as specific heat or velocity of sound of a dissociating mixture. The method presented is applicable to a wide variety of problems that include (1) combustion at constant pressure or volume; and (2) isentropic expansion to an assigned pressure, temperature, or Mach number. Tables of thermodynamic functions needed with this method are included for 42 substances for convenience in numerical computations.

Huff, Vearl N; Gordon, Sanford; Morrell, Virginia E

1951-01-01

386

Formation of Lipid-Based Nanodiscs and Their Dependence of Temperature and Chemical Composition  

NASA Astrophysics Data System (ADS)

Phospholipid mixtures composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)(DPPG) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (ammonium salt) (PEGylated DSPE) and cholestrol were found to form nanodiscs (bicelles) in both non-ionic and phosphate buffer solutions . The structure of the aggregates is resolved using dynamic light scattering, transmission electron microscopy and small angle neutron scattering. The effects of temperature and chemical composition (e.g., PEGylated DSPE and cholesterol) on the structural variation and polydispersity will be discussed in this presentation. These nanodiscs have the potential of serving as a model delivery carrier for hydrophobic molecules for their biological compatibility and capability of incorporating with targeting molecules.

Liu, Ying; Yang, Yongkun; Nieh, Mu-Ping

2012-02-01

387

Chemical compositions of the essential oils of stems, leaves and flowers of Prangos acaulis (Dc) Bornm.  

PubMed

Chemical composition of the essential oils obtained of stems, leaves and flowers of the Prangos acaulis, at full flowering stage were isolated by hydrodistilation method and investigated by GC/MS. A total of 11 compounds constituting 100% of stems oil, eighteen compounds constituting 99.74% of leaves oil and 22 compounds constituting 98.18% of flowers oil have been identified and quantified. The major components of stems oil were 3-ethylidene-2-methyl-1-hexen-4-yne (56.8%) and alpha-pinene (34.2%). The major components of leaves oil were a-pinene (39.54%), 3-ethylidene-2-methyl-1-hexen-4-yne (37.94%) and alpha-terpinene (10.9%) and the major components of flowers oil were alpha-pinene (25.04%), 3-ethylidene-2-methyl-1-hexen-4-yne (23.51%), alpha-terpinene (17.26%) and limonene (13.64%). PMID:19070103

Meshkatalsadat, Mohammad Hadi; Mirzaei, Hossein Hadavand

2007-08-15

388

Influence of cluster zone leaf removal on Pinot noir grape chemical and volatile composition.  

PubMed

The influence of cluster-zone leaf removal on Pinot noir vine growth and fruit chemical and volatile composition was investigated in 3years. Different severities of leaf removal (0%, 50%, 100%) were imposed during the pea-size stage of development from the cluster zone. Results show that cluster-zone leaf removal had little influence on vine growth, crop load, or grape maturity in terms of total soluble solids (TSS), pH or titratable acidity (TA) at harvest. However, 100% leaf removal resulted in higher concentrations of quercetin glycoside in grapes compared to 0% leaf removal. The 100% leaf removal also increased concentrations of petunidin- and malvidin-3-monoglucoside anthocyanins in two out of 3years (2010 and 2012) by an average of 62% and 53%, respectively. In addition, 100% leaf removal resulted in higher concentrations of ?-damascenone, and some bound-form terpenoids. The increases in ?-damascenone were positively correlated to the increased sunlight exposure. PMID:25466040

Feng, Hui; Yuan, Fang; Skinkis, Patricia A; Qian, Michael C

2015-04-15

389

Stable isotope and chemical compositions of European and australasian ciders as a guide to authenticity.  

PubMed

This paper presents a data set derived from the analysis of bottled and canned ciders that may be used for comparison with suspected counterfeit or substitute products. Isotopic analysis of the solid residues from ciders (predominantly sugar) provided a means to determine the addition of C4 plant sugars. The added sugars were found to comprise cane sugar, high-fructose corn syrup, glucose, or combinations. The majority of ciders from Australia and New Zealand were found to contain significant amounts of added sugar, which provided a limited means to distinguish these ciders from European ciders. The hydrogen and oxygen isotopic compositions of the whole ciders (predominantly water) were shown to be controlled by two factors, the water available to the parent plant and evaporation. Analysis of data derived from both isotopic and chemical analysis of ciders provided a means to discriminate between regions and countries of manufacture. PMID:25536876

Carter, James F; Yates, Hans S A; Tinggi, Ujang

2015-01-28

390

Spectrum and chemical composition of the remarkable planetary nebula NGC 6537  

PubMed Central

Observations with the image tube scanner at the Shane 3-m telescope are combined with data obtained with the International Ultraviolet Explorer to assess the spectrum of the remarkable high-excitation planetary nebula NGC 6537. We have analyzed the spectrum of this nitrogen-rich object with the aid of the theoretical nebular models. The models permit one to estimate the fraction of unobservable ions of abundant elements. On the scale log N(H) = 12, the logarithmic abundance values for He, C, N, and O are as follows: [Table: see text] The abundances of Ne S, Cl, and Ar appear to be essentially solar to within a factor of 2. Our interpretation is that the progenitor of NGC 6537 had a chemical composition not differing greatly from that of the Sun. In the course of its prenebular evolution, C and probably O were converted to N and much H was converted to helium. PMID:16593550

Feibelman, Walter; Aller, Lawrence H.; Keyes, C. D.; Czyzak, S. J.

1985-01-01

391

Anticancer and antimicrobial activities and chemical composition of the birch mazegill mushroom Lenzites betulina (higher Basidiomycetes).  

PubMed

The anticancer properties, antibiotic activity, and chemical composition of Lenzites betulina ethanol extract (EE) were evaluated. Eight compounds including 5 sterols were isolated from L. betulina, and 7 compounds were isolated from L. betulina for the first time. The EE displayed strong anticancer activity against tumor cell line MDA-MB-231, with a half maximal inhibitory concentration of 51.46 ?g/mL, and there was 83.15% inhibition at a concentration of 200 ?g/mL (MTT assay). The antimicrobial activity of the EE was evaluated against 6 microorganisms-Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Fusarium graminearum, Gibberella zeae, and Cercosporella albo-maculans-and the EE showed moderate antibiotic activity. These results suggest that L. betulina could be a good anticancer and antibiotic agent. PMID:25271861

Liu, Kun; Wang, Jun-Li; Zhao, Le; Wang, Qian

2014-01-01

392

Chemical composition and antiphytoviral activity of essential oil of Micromeria graeca.  

PubMed

Phytochemical analysis of the essential oils of Micromeria graeca (L.) Rchb from Vis and Komiza on the island of Vis (Croatia) showed them to have a similar chemical composition. The oxygenated sesquiterpene alpha-bisabolol was a major component of both oils with percentages of 13.9% in the oil from Vis and 15.5% in the oil from Komiza. A comparison of the mean number of lesions on the essential oil-treated Chenopodium quinoa plants infected with satellite-associated cucumber mosaic virus (satCMV) with the corresponding control showed that the oil from Vis caused delay in the development and reduction of the number of lesions by 59.3%. The essential oil of M. graeca from Komiza was not effective in the reduction of satCMV infection. PMID:23074916

Vuko, Elma; Dunki?, Valerija; Bezi?, Nada; Rusci?, Mirko; Kremer, Dario

2012-09-01

393

Anisotropic Compositional Expansion and Chemical Potential for Amorphous Lithiated Silicon under Stress Tensor  

PubMed Central

Si is a promising anode material for Li-ion batteries, since it absorbs large amounts of Li. However, insertion of Li leads to 334% of volumetric expansion, huge stresses, and fracture; it can be suppressed by utilizing nanoscale anode structures. Continuum approaches to stress relaxation in LixSi, based on plasticity theory, are unrealistic, because the yield strength of LixSi is much higher than the generated stresses. Here, we suggest that stress relaxation is due to anisotropic (tensorial) compositional straining that occurs during insertion-extraction at any deviatoric stresses. Developed theory describes known experimental and atomistic simulation data. A method to reduce stresses is predicted and confirmed by known experiments. Chemical potential has an additional contribution due to deviatoric stresses, which leads to increases in the driving force both for insertion and extraction. The results have conceptual and general character and are applicable to any material systems. PMID:23563528

Levitas, Valery I.; Attariani, Hamed

2013-01-01

394

Heat, Moisture and Chemical Resistant Polyimide Compositions and Methods for Making and Using Them  

NASA Technical Reports Server (NTRS)

Polyimides having a desired combination of high thermo-oxidative stability, low moisture absorption and excellent chemical and corrosion resistance are prepared by reacting a mixture of compounds including (a) 3,3',4,4'- benzophenonetetracarboxylic dianhydride (BTDA), (b) 3,4'- oxydianiline (3,4'-ODA), and (c) 5-norbornene-2,3- dicarboxylic anhydride (NA) in a high boiling, aprotic solvent to give 5 to 35% by weight of polyamic acid solution. The ratio of (a), (b), and (c) is selected to afford a family of polyimides having different molecular weights and properties. The mixture first forms a polyamic acid precursor. Upon heating at or above 300 C, the polyamic acids form polyimides, which are particularly suitable for use as a high temperature coating, adhesive, thin film, or composite matrix resin.

Pater, Ruth H. (Inventor)

2004-01-01

395

Chemical Composition of the Epicuticular and Intracuticular Wax Layers on Adaxial Sides of Rosa canina Leaves  

PubMed Central

Background and Aims The waxy cuticle is the first point of contact for many herbivorous and pathogenic organisms on rose plants. Previous studies have reported the average composition of the combined wax extract from both sides of rose leaves. Recently, the compositions of the waxes on the adaxial and abaxial surfaces of Rosa canina leaves were determined separately. In this paper, a first report is made on the compositions of the epicuticular and intracuticular wax layers of Rosa canina leaves. The methods described enable the determination of which compounds are truly available at the surface for plant–organism interactions. METHOD An adhesive was used to mechanically strip the epicuticular wax from the adaxial leaf surface and the removal was visually confirmed using scanning electron microscopy. After the epicuticular wax had been removed, the intracuticular wax was then isolated using standard chemical extraction. Gas chromatography, flame ionization detection and mass spectrometry were used to identify and quantify compounds in the separated wax mixtures. Key Results The epicuticular wax contained higher concentrations of alkanes and alkyl esters but lower concentrations of primary alcohols and alkenols when compared to the intracuticular wax. In addition, the average chain lengths of these compound classes were higher in the epicuticular wax. Secondary alcohols were found only in the epicuticular layer while triterpenoids were restricted mainly to the intracuticular wax. Conclusions A gradient exists between the composition of the epi- and intracuticular wax layers of Rosa canina leaves. This gradient may result from polarity differences, in part caused by differences in chain lengths. The outer wax layer accessible to the phyllosphere showed a unique composition of wax compounds. The ecological consequences from such a gradient may now be probed. PMID:17933845

Buschhaus, Christopher; Herz, Hubert; Jetter, Reinhard

2007-01-01

396

Coatings with controlled porosity and chemical properties  

DOEpatents

Coatings and sensors are described having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.

Frye, G.C.; Brinker, C.J.; Doughty, D.H.; Bein, T.; Moller, K.

1993-07-06

397

Coatings with controlled porosity and chemical properties  

DOEpatents

Coatings and sensors having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.

Frye, Gregory C. (P.O. Box 763, Cedar Crest, NM 87008); Brinker, C. Jeffrey (14 Eagle Nest Dr., NE., Albuquerque, NM 87122); Doughty, Daniel H. (11724 Woodmar La., NE., Albuquerque, NM 87111); Bein, Thomas (1114 Princeton Dr., NE., Albuquerque, NM 87106); Moller, Karin (1114 Princeton Dr., NE., Albuquerque, NM 87106)

1993-01-01

398

Coatings with controlled porosity and chemical properties  

DOEpatents

Coatings and sensors having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.

Frye, Gregory C. (Bernalillo County, NM); Brinker, C. Jeffrey (Albuquerque, NM); Doughty, Daniel H. (Albuquerque, NM); Bein, Thomas (Albuquerque, NM); Moller, Karin (Albuquerque, NM)

1996-01-01

399

Controls on the chemical and isotopic compositions of urban stormwater in a semiarid zone  

NASA Astrophysics Data System (ADS)

The temporal variations in the chemical and isotopic compositions of urban stormwater under different land uses, and their dependence on physical parameters such as precipitation intensity, stormwater discharge, cumulative stormwater volumes and the size of the drainage area, were investigated in the coastal city of Ashdod, Israel. During 2000/2001 and 2001/2002, 46 stormwater events were intensively monitored for precipitation distribution and intensity at three stations across the city, and for stormwater discharge at seven stations draining 85% of the city area. Sixty-eight and 202 precipitation samples were collected and analyzed for chemical and isotopic compositions, respectively, as were 186 stormwater samples, collected from the drains during 15 of the 46 events. Land use had only a minor effect on the concentrations of major ions and trace elements. Conversely, the concentrations and variety of volatile and semi-volatile organic compounds were significantly higher in stormwater generated in the industrial area than in that draining from residential areas. Ion and trace-metal concentrations were very low (below drinking-water standards) in 97% of the stormwater samples collected from all drains. Stormwater concentrations were higher at stations draining a larger area, thereby linking concentrations to the length of the stormwater flow paths. A first-flush effect was documented on both a seasonal and event basis for both ions and trace elements. The high concentrations of fecal coliform bacteria exceeded the drinking-water standards and displayed a random pattern. The isotopic ratios of oxygen and hydrogen in the stormwater suggest very little exposure to the atmosphere, resulting in very limited fractionation. The presence of fecal coliforms, ammonium in some samples, and specific ratios of oxygen and nitrogen isotopes, suggest that although the sewer and stormwater-collection systems are separated, wastewater, possibly from overflowing sewers, contributed to the drained stormwater.

Asaf, L.; Nativ, R.; Shain, D.; Hassan, M.; Geyer, S.

2004-07-01

400

Chemical composition and RT[sub NDT] determinations for Midland weld WF-70  

SciTech Connect

The Heavy-Section Steal Irradiation Program Tenth Irradiation Series has the objective to investigate the affects of radiation on the fracture toughness of the low-upper-shelf submerged-arc welds (B W designation WF-70) in the reactor pressure vessel of the canceled Midland Unit 1 nuclear plant. This report discusses determination of variations in chemical composition And reference temperature (RT[sub NDT]) throughout the welds. Specimens were machined from different sections and through thickness locations in both the beltline and nozzle course welds. The nil-ductility transition temperatures ranged from [minus]40 to [minus]60[degrees]C ([minus]40 and [minus]76[degrees]F) while the RT[sub NDT]S, controlled by the Charpy behavior, varied from [minus]20 to 37[degrees]C ([minus]4 to 99[degrees]F). The upper-shelf energies varied from 77 to 108 J (57 to 80 ft-lb). The combined data revealed a mean 41-J (30-ft-lb) temperature of [minus]8[degrees]C (17[degrees]F) with a mean upper-shelf energy of 88 J (65 ft-lb). The copper contents range from 0.21 to 0.34 wt % in the beltline weld and from 0.37 to 0.46 wt % in the nozzle course weld. Atom probe field ion microscope analyses indicated substantial depletion of copper in the matrix but no evidence of copper clustering. Statistical analyses of the Charpy and chemical composition results as well as interpretation of the ASME procedures for RT[sub NDT] determination are discussed.

Nanstad, R.K.; McCabe, D.E.; Swain, R.L.; Miller, M.K. (Oak Ridge National Lab., TN (United States))

1992-12-01

401

Evaluation of variability in material properties and chemical composition for Midland reactor weld WF-70  

SciTech Connect

The Heavy-Section Steel Irradiation (HSSI) Program at Oak Ridge National Laboratory (ORNL) includes a task, the Tenth Irradiation Series, to investigate the effects of radiation on the fracture toughness of the low upper-shelf submerged-arc welds in the reactor pressure vessel (RPV) of the canceled Midland Unit 1 nuclear plant. The welds carry the Babcock and Wilcox Co. (B and W) designation WF-70, a weld which exists in many commercial pressurized-water reactors. Various sections of both the beltline weld and the nozzle course weld were studied. A major part of the study involved the determination of variations in chemical composition and reference temperature (RT{sub NDT}) throughout the as-received welds. The RT{sub NDT}s, all controlled by the Charpy behavior, varied from {minus}20 to 37 C ({minus}4 to 99 F) while the upper-shelf energies varied from 77 to 108 J (57 to 80 ft-lb). Even though all the welds carry the WF-70 designation, the bulk copper contents range from 0.21 to 0.34 wt % in the beltline weld and from 0.37 25 data sets of the Midland weld was 17 C and is comparable to that for the high upper-shelf HSSI weld 72W and that from 13 data sets for HSST Plate 01. Statistical analyses of the Charpy and chemical composition results are discussed. Although the NDT temperatures and CVN transition temperature ranges were similar for the two welds, the fracture toughness results indicated that the nozzle course weld had a 27 C (49 F) higher transition temperature than the beltline weld. Some postirradiation data are available and are presented in this paper, but the major part of the irradiation effects study will be reported subsequently.

Nanstad, R.K.; McCabe, D.E.; Swain, R.L. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1999-10-01

402

Phytotoxic Activity and Chemical Composition of Aqueous Volatile Fractions from Eucalyptus Species  

PubMed Central

The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph–mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

2014-01-01

403

Chemical composition and antimicrobial and antioxidant activities of Mentha (longifolia L. and viridis) essential oils.  

PubMed

The study was aimed to investigate essential oil chemical composition (gas chromatography/flame ionization detection [GC-FID] and gas chromatography/mass spectrometry [GC-MS]) and antioxidant (1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate [ABTS] assays) and antimicrobial (Gram-positive and Gram-negative bacteria, fungi, and yeast) activities of essential oils extracted from leaves of Mentha longifolia L. and Mentha viridis. GC-MS analysis revealed that M. longifolia was constituted by pulegone (54.41%) as a major component followed by isomenthone (12.02%), 1,8-cineole (7.41%), borneol (6.85%), and piperitenone oxide (3.19%). M. viridis was rich in carvone (50.47%), 1,8-cineole (9.14%), and limonene (4.87%). The antioxidant activity by ABTS assay showed IC(50) values of 476.3 +/- 11.7 and 195.1 +/- 4.2 mg/L for M. longifolia and M. viridis, respectively, the DPPH assays have resulted in a moderate IC(50) (>8000 mg/L and 3476.3 +/- 133 mg/L for M. longifolia and M. viridis, respectively). Antimicrobial activity showed that Listeria monocytogenes and Klebsiella pneumoniae bacteria were more inhibited by the 2 essential oils tested. Escherichia coli was least susceptible. A strong activity was also observed on fungi and yeasts. Carvone, thymol, and piperitone oxide have not been detected in Tunisian M. longifolia. Camphor is reported for the 1st time for M. viridis. Antioxidant and antibacterial activities were correlated to chemical composition. PMID:19895481

Mkaddem, Mounira; Bouajila, Jalloul; Ennajar, Monia; Lebrihi, Ahmed; Mathieu, Florence; Romdhane, Mehrez

2009-09-01

404

Phytotoxic activity and chemical composition of aqueous volatile fractions from Eucalyptus species.  

PubMed

The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

2014-01-01

405

Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export.  

PubMed

Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon (DOC) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2-3 g C m(-2) ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m(-2) ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and increasing catchment DOC export. PMID:24753046

Olefeldt, David; Roulet, Nigel T

2014-10-01

406

Characterization of anticancer, antimicrobial, antioxidant properties and chemical compositions of Peperomia pellucida leaf extract.  

PubMed

Peperomia pellucida leaf extract was characterized for its anticancer, antimicrobial, antioxidant activities, and chemical compositions. Anticancer activity of P. pellucida leaf extract was determined through Colorimetric MTT (tetrazolium) assay against human breast adenocarcinoma (MCF-7) cell line and the antimicrobial property of the plant extract was revealed by using two-fold broth micro-dilution method against 10 bacterial isolates. Antioxidant activity of the plant extract was then characterized using ?, ?-diphenyl-?-picrylhydrazyl (DPPH) radical scavenging method and the chemical compositions were screened and identified using gas chromatography-mass spectrometry (GC-MS). The results of present study indicated that P. pellucida leaf extract possessed anticancer activities with half maximal inhibitory concentration (IC(50)) of 10.4 ± 0.06 µg/ml. The minimum inhibitory concentration (MIC) values were ranged from 31.25 to 125 mg/l in which the plant extract was found to inhibit the growth of Edwardsiella tarda, Escherichia coli, Flavobacterium sp., Pseudomonas aeruginosa and Vibrio cholerae at 31.25 mg/l; Klebsiella sp., Aeromonas hydrophila and Vibrio alginolyticus at 62.5 mg/l; and it was able to control the growth of Salmonella sp. and Vibrio parahaemolyticus at 125 mg/l. At the concentration of 0.625 ppt, the plant extract was found to inhibit 30% of DPPH, free radical. Phytol (37.88%) was the major compound in the plant extract followed by 2-Naphthalenol, decahydro- (26.20%), Hexadecanoic acid, methyl ester (18.31%) and 9,12-Octadecadienoic acid (Z,Z)-, methyl ester (17.61%). Findings from this study indicated that methanol extract of P. pellucida leaf possessed vast potential as medicinal drug especially in breast cancer treatment. PMID:22071643

Wei, Lee Seong; Wee, Wendy; Siong, Julius Yong Fu; Syamsumir, Desy Fitrya

2011-01-01

407

Gradients in dust chemical composition in protoplanetary disks: analogies with the Solar System  

NASA Astrophysics Data System (ADS)

Clues to planet-forming processes are provided by the properties of the dust grains in protoplanetary disks and in cometary nuclei in our own Solar System. We present a compositional analysis of the 10µm and 20µm silicate emission features for young protoplanetary disks around FGKM stars. We find an increase in the crystallinity levels towards larger radii, such that the median crystalline mass fraction is higher in the outer cold disk region compared to the inner warm parts of the disk. For nearly 80% of the disks, the mass fraction of small ISM-like dust grains is negligible (< 5%) in the outer cold disk region. The median crystalline mass fraction in disks around late-type stars is found to be a factor of ~2 higher than the median for the higher mass FGK type stars. The relatively high abundance of crystalline silicates in the outer cold regions of protoplanetary disks provides an interesting analogy to comets. In this context, we will discuss the applicability of the various mechanisms that have been proposed for comets on the formation and the outward transport of high-temperature material. A (weak) anti-correlation between the X-ray emission strength and the extent of crystallinity in the disk is observed, suggesting X-rays to be an important dust amorphization agent in these disks. This work has highlighted the ubiquity of Solar System like chemical signatures in young protoplanetary disks, and suggests that protoplanets that form closer to a low-mass star can have a different chemical composition from those that formed farther away.

Riaz, Basmah; Kelley, M.; Campins, H.

2014-11-01

408

Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical vapor deposition  

E-print Network

grown by high-pressure chemical vapor deposition have been studied. Atomic hydrogen cleaning produced and heterostructures--which can be accomplished by low- pressure metalorganic chemical vapor deposition MOCVD --the- rium vapor pressure of nitrogen during growth. This requires different approaches in growing structures

Dietz, Nikolaus

409

Chemical oven technology and its application in AlN composites fabricated under microgravity condition  

Microsoft Academic Search

The microgravity experiments of fabrication materials by using TiC chemical ovens have been performed on the parabolic flight plane. The gravity behaviors in the combustion reactions of chemical ovens themselves during the aircraft parabolic flight were investigated. The results show that, the combustion temperatures and reactions vary with different gravity levels. These influences are related with the function of gravity

Guojian J. Jiang; Qingxue X. Zhang; Hanrui R. Zhuang; Wenlan L. Li; Maozi Z. Li

2003-01-01

410

Chemical composition, functional and sensory characteristics of wheat-taro composite flours and biscuits.  

PubMed

The physicochemical, alveographic and sensory characteristics of precooked taro-wheat composite flours and their biscuits were investigated. A 2x7 factorial design consisting of two varieties of taro flour (Red Ibo Ngaoundere, RIN, and egg-like varieties) and 7 levels of wheat substitutions (0, 5, 10, 15, 20, 25 and 30 %) was used for this purpose. It was observed that water absorption capacity (range 95-152 g/100 g), water solubility index (range 18.8-29.5 g/100 g) and swelling capacity (range 125.4-204.6 mL/100 g) of composite flours significantly (p?composite taro-wheat dough exhibited elasticity indices acceptable for the production of baking products, whereas at all levels of taro substitution, the composite biscuits samples were either acceptable as or better (5-10 % substitution with RIN flour) than 100 % wheat biscuit. PMID:25190844

Himeda, Makhlouf; Njintang Yanou, Nicolas; Fombang, Edith; Facho, Balaam; Kitissou, Pierre; Mbofung, Carl M F; Scher, Joel

2014-09-01

411

Genetic selection, sex and feeding treatment affect the whole-body chemical composition of sheep.  

PubMed

Hypotheses on total body chemical composition were tested using data from 350 Suffolk sheep grown to a wide range of live weights, and fed in a non-limiting way, or with reduced amounts of feed, or ad libitum on feeds of reduced protein content. The sheep were from an experiment where selection used an index designed to increase the lean deposition rate while restricting the fat deposition rate. Ultrasound muscle and fat depths were the only composition measurements in the index. The animals were males and females from a selection (S) line and its unselected control (C). The protein content of the lipid-free dry matter was unaffected by live weight, sex or feeding treatment with only a very small effect of genetic line (0.762 kg/kg in S and 0.753 kg/kg in C; P < 0.05). The form of the relationship between water and protein was not affected by any of the factors; in the different kinds of sheep it was consistent with no effect other than through differences in mature protein weight. The water : protein ratio at maturity was estimated as 3.45. Over the whole dataset, lipid weight (L) increased with protein weight (P) according to L = 0.3135 × P1.850. Allowing for this scaling, fatness increased on low-protein feeds, was greater in females than in males and in C than in S (P < 0.001). Lipid content (g/kg fleece-free empty body weight) was reduced by restricted feeding only in males at the highest slaughter weight (114 kg). The lines differed in lipid content (P < 0.001) with means of 265.1 g/kg for C and 237.3 g/kg for S. Importantly, there was no interaction between line and feeding treatments. A higher proportion of total body protein was in the carcass in S than in C (0.627 v. 0.610; P < 0.001). For lipid, the difference was reversed (0.736 v. 0.744; P < 0.05). The total energy content increased quadratically with slaughter weight. At a particular weight, the energy content of gain was higher in females than in males and in C than in S. Genetic selection affected body composition at a weight favouring the distribution of protein to the carcass and lipid to the non-carcass. Once allowing for effects of genetic selection, sex and feeding treatment on fatness, simple rules can be used to generate the chemical composition of sheep. PMID:22444916

Lewis, R M; Emmans, G C

2007-11-01

412

Extra-red transneptunian objects and Centaurs: Composition and chemical history  

NASA Astrophysics Data System (ADS)

We present the results of a systematic analysis of the surface composition of ten of the reddest transneptunian objects (TNOs). The goal of the analysis is to determine the current chemical compositions of these extra-red objects and investigate possible paths of chemical evolution since formation. The sample consists of six objects from the classical and resonant populations, one detached object, and three Centaurs. The classical and resonant objects are expected to be similar to each other in composition, while the surfaces of the three Centaurs could have been significantly modified as their orbits evolved. Furthermore, Brown et al. (Brown, M.E., Schaller, E.L., & Fraser, W.C., 2011. A Hypothesis for the Color Diversity of the Kuiper Belt. ApJL, 739, L60) propose that objects with red color are rich in methanol. The available data consist of broad-band photometric measurements in the wavelength range between 0.3 and 4.5 ? m. The photometric measurements are scaled to the albedo at 0.55 ? m to yield an approximation of the spectral shape of each object that is then compared to a library of synthetic spectra of mixtures of materials known to be present on the surfaces of TNOs. Errors as well as phase-angle differences are taken into account as part of the fitting uncertainty. For each object, we obtain a range of compositions that match their spectral distribution within the estimated errors. This yields the likelihood for the various materials to be present on the surface as well as a rough measure of the uncertainty of the estimate. All objects show presence of methanol and/or methane on their surface, supporting the Brown et al. (2011) hypothesis. To further analyze our results, ices are grouped into 'stable' (H_2O), 'partially stable' (CH_3OH, CO_2), and 'volatile' (CH_4, CO, N_2). Our results show some difference in the amount of 'volatile' and 'partially stable' ices among the classical and resonant objects. A trend in the sense of less ice present on closer and smaller objects is apparent, possibly related to the objects' ability to retain those ices and to the ices available in the solar nebula at those distances at the time of formation. Pholus, one of the Centaurs, exhibits a lower abundance of 'volatile' ices and enhancement of organic and carbonaceous material with respect to the other Centaurs. Since Centaurs are believed to originate from TNOs captured into fairly short-lived orbits closer to the Sun, our findings are consistent with the idea that Pholus has recently lost to sublimation some of its 'volatile' ice reservoir, exposing more of its native organic material. A similar behavior is visible for the classical and resonant objects, although the trend is very weak when the carbonaceous material is not taken into account. This hints at the possibility that irradiation weathering might be acting on the closer objects, actively transforming red organic into dark carbonaceous material. More distant objects, on the other hand, might still be pristine in their composition, suggesting that their organic component might have originated in the early stages of their accretion to planetesimals or even before as chemical changes in the solar nebula.

Dalle Ore, C. M.; Barucci, M. A.; Cruikshank, D. P.; Emery, J. P.

2014-07-01

413

The Regional Patterns of Chemical Composition in the Otolith Core of Larval Fish  

NASA Astrophysics Data System (ADS)

The elemental composition of fish otoliths can record the environmental information because once a trace element is deposited in the otolith; it presents a permanent record of the environmental conditions experienced by the fish at a particular time. The elemental signature of the otolith nucleus, the area lying within the first annual growth ring, is likely to be characteristic of the nursery areas of the species, and could be used as biological tracer for tracking origin and dispersal. However, ocean acidification may alter otolith growth and element incorporation, and it is important to establish baseline information about the sources of variation - both biotic and abiotic. The objectives of this study, as part of the wider CalMarO network, is to examine the regional differences in the otolith cores of selected fish species, contrast these differences with those measured between these same species in areas where their larvae co-exist and to find out the maternal effect to the chemical composition during the first forming of otoliths. The laboratory and field experiments were included to produce otolith material reflecting the maternal and regional patterns. Otolith composition was measured using laser-ablation ICPMS. For clarifying the regional patterns, juveniles from six locations and seven spawning groups along the west of the British Isles and larvae from the North Sea were sampled to distinguish the origin of spawning herring. There are three main nursery-ground groups, the Irish Sea, Scottish sea lochs and the Minch, contributing to the spawning herring in the west of the British Isles according to the otolith elemental composition data. However, the spawning origin of the North Sea herring larvae was still unclear. The otolith concentrations of Li, Na, Mg, Mn, Cu, Ru and Sr were significantly different among nursery-ground populations. Together with length-at-age data, at least two nursery-ground groups contributed to each spawning population. The juveniles from western Irish Sea and the Stanton Bank contributed most to the spawning populations. The otolith signature (without length-at-age information) indicated that the North Sea larvae contributed mostly to the spawning herring from the Dingle and the Cape Wrath. The results suggested that there might be different current systems, which drove the larval dispersal both northward and southward from the spawning ground to the North Sea. Although there might be mixtures and interconnections among the west coast herrings, which resulted in the similar otolith chemical signals, the otolith chemical composition still provided useful information of regional differences for tracing back the origin of spawning populations. The detailed current system may be needed to provide more inference for the larval dispersal and the linkage between nursery-ground and spawning populations. * present address: Biodiversity Research Center, Academia Sinica, Taiwan, R.O.C.

Chang, M. Y.; Geffen, A. J.; Nash, R. D. M.; Clemmesen, C.

2012-04-01

414

Aligned Carbon Nanotube Reinforced Silicon Carbide Composites by Chemical Vapor Infiltration  

SciTech Connect

Owing to their exceptional stiffness and strength1 4, carbon nanotubes (CNTs) have long been considered to be an ideal reinforcement for light-weight, high-strength, and high-temperature-resistant ceramic matrix composites (CMCs)5 10. However, the research and development in CNT-reinforced CMCs have been greatly hindered due to the challenges related to manufacturing including poor dispersion, damages during dispersion, surface modification, densification and sintering, weak tube/matrix interfaces, and agglomeration of tubes at the matrix grain boundaries5,11. Here we report the fabrication of high-quality aligned CNT/SiC composites by chemical vapor infiltration (CVI), a technique that is being widely used to fabricate commercial continuous-filament CMCs12 15. Using the CVI technique most of the challenges previously encountered in the fabrication of CNT composites were readily overcome. Nanotube pullouts, an important toughening mechanism for CMCs, were consistently observed on all fractured CNT/SiC samples. Indeed, three-point bending tests conducted on individual CNT/SiC nanowires (diameters: 50 200 nm) using an atomic force microscope show that the CNT-reinforced SiC nanowires are about an order of magnitude tougher than the bulk SiC. The tube/matrix interface is so intimate and the SiC matrix is so dense that a ~50-nm-thick SiC coating can effectively protect the inside nanotubes from being oxidized at 1600 C in air. The CVI method may be extended to produce nanotube composites from a variety of matrix

Gu, Zhan Jun [University of Georgia, Athens, GA; Yang, Ying Chao [University of South Carolina, Columbia; Li, Kai Yuan [University of Georgia, Athens, GA; Tao, Xin Yong [University of South Carolina, Columbia; Eres, Gyula [ORNL; Howe, Jane Y [ORNL; Zhang, Li Tong [Northwestern Polytechnical University, Xi'an, China; Li, Xiao Dong [University of South Carolina, Columbia; Pan, Zhengwei [ORNL

2011-01-01

415

Effect of chemical composition on superconductivity and magnetism in layered ruthenocuprates.  

PubMed

The ruthenium-based layered cuprates RuSr(2)GdCu(2)O(8) (RuGd1212) can be considered naturally occurring magnetic and superconducting multilayer systems. We have concentrated on the preparation of RuGd1212-type compounds with nominally stoichiometric composition under ambient pressure conditions. For small rare earth ions R  = Gd, Eu (and Sm), single phase compounds are obtained with the typical ordered layered structure and no significant changes of physical properties. With large rare earth ions (R  = Nd, Pr), multiphase samples are obtained. In these cases, no ordered layered structure was observed. The effect of substituting Sr(2+) with the smaller Ca(2+) and larger Ba(2+) is examined. A different number and different types of phases in equilibrium are found with different alkaline earths (A  = Ca, Sr, Ba) at the nominal RuA(2)NdCu(2)O(8) composition. The variation in the mismatch of the A/Nd size does not lead to the formation of an ordered layered RuA(2)NdCu(2)O(8) compound. Chemical transport in an open system was used to vary the Ru content in the RuGd1212 samples during the annealing step. With an increase of the Ru mass transport to the sample, the composition can be driven beyond the limit of the homogeneity range. Systematic changes in the phase composition of the resulting sample were observed. The magnetic and superconducting transition temperatures vary in a systematic way and are attributed to a variation of the Ru content in the RuR1212 phase. PMID:21828434

Casini, E; Kempf, M; Krämer, J; Braun, H F

2009-06-24

416

Thermo-chemical constraints on the interior structure and composition of the lunar mantle  

NASA Astrophysics Data System (ADS)

Based on a self-consistent thermodynamic-geophysical approach, we convert the recent seismic models of the lunar mantle to the temperature-depth profiles using Gibbs free energy minimization and petrological constraints in the Na2O-TiO2-CaO-FeO-MgO-Al2O3-SiO2 system. Our calculations are unable to explain the reasonable distribution of temperature for a single homogeneous composition throughout the entire lunar mantle with concentrations of CaO and Al2O3 in the range of 2-6.5%, and FeO content between 8.5% and 13%. The results lend support to the chemically stratified lunar mantle with a change in composition from predominantly pyroxenite upper mantle depleted in Ca and Al to predominantly fertile lower mantle enriched in Ca and Al with larger amounts of garnet. Such a zoned structure places significant constraints on any theory of lunar origin. Unlike the Earth’s mantle, compositional effects play a dominant role in determining the lunar mantle temperatures of the same observational model. Seismically derived temperatures allow us to constrain thermal structure of the lunar mantle and estimate the upper mantle heat flow (3.8-4.7 mW m-2), which is not consistent with that found from the Apollo heat flow and thorium abundance measurements. Lower mantle temperatures are well below the probable solidus condition and can be evaluated at the level of 1420-1550 °C at the core-mantle boundary without requiring a melt layer. We find that regardless of the composition, the positive S-wave velocity gradient in the lunar mantle leads to a negative temperature gradient, which has no physical basis. The resulting temperature profiles provide an effective independent tool that allows us to discriminate between the available seismic and petrological models.

Kuskov, Oleg L.; Kronrod, Victor A.; Kronrod, Ekaterina V.

2014-10-01

417

A Statistical Approach for Judging Stability of Whole Mixture Chemical Composition over Time for Highly Complex Disinfection By-Product Mixtures from EPA's Four Lab Study  

EPA Science Inventory

Chemical characterization of complex mixtures and assessment of stability over time of the characterized chemicals is crucial both to characterize exposure and to use data from one mixture as a surrogate for other similar mixtures. The chemical composition of test mixtures can va...

418

Aroma chemical composition of red wines from different price categories and its relationship to quality.  

PubMed

The aroma chemical composition of three sets of Spanish red wines belonging to three different price categories was studied by using an array of gas chromatographic methods. Significant differences were found in the levels of 72 aroma compounds. Expensive wines are richest in wood-related compounds, ethyl phenols, cysteinil-derived mercaptans, volatile sulfur compounds, ethyl esters of branched acids, methional, and phenylacetaldehyde and are poorest in linear and branched fatty acids, fusel alcohols, terpenols, norisoprenoids, fusel alcohol acetates, and ethyl esters of the linear fatty acids; inexpensive wines show exactly the opposite profile, being richest in E-2-nonenal, E-2-hexenal, Z-3-hexenol, acetoin, and ethyl lactate. Satisfactory models relating quality to odorant composition could be built exclusively for expensive and medium-price wines but not for the lower-price sample set in which in-mouth attributes had to be included. The models for quality reveal a common structure, but they are characteristic of a given sample set. PMID:22480297

Juan, Felipe San; Cacho, Juan; Ferreira, Vicente; Escudero, Ana

2012-05-23

419

Aerosol assisted chemical vapour deposition of Cu-ZnO composite from single source precursors.  

PubMed

Two heterobimetallic precursors [Zn(TFA)3(micro-OH)Cu3(dmae)3Cl].THF (1) and [Zn(TFA)4Cu3(dmae)4] (2) [dmae=N,N-dimethylaminoethanolate and TFA=trifluoroacetate], have been synthesized and characterized by their melting points, elemental analysis, FT-IR spectroscopy, mass spectrometry, TGA and single crystal X-ray diffraction methods. Both complexes were used to deposit thin films of Cu-ZnO composite on glass substrates by aerosol assisted chemical vapor deposition (AACVD) method. The films were characterized by "scotch tape" test for adhesion, thickness measurement as a function of temperature, EDX for composition, SEM for surface morphology and XRD for crystalline phases. Thin film deposition studies at 250, 325, 400, 475 degrees C indicated the increase in thickness with temperature reaching a maximum at 400 degrees C and then decreasing. EDX and PXRD results showed the uniform distribution of cubic metallic copper and hexagonal zinc oxide phases which make them useful for nanocatalysis on structured surfaces. PMID:19587992

Shahid, Muhammad; Mazhar, Muhammad; Hamid, Mazhar; O'Brien, Paul; Malik, Mohammad A; Helliwell, Madeleine; Raftery, James

2009-07-28

420

Chemical composition and antimicrobial activity of the essential oils from four Ruta species growing in Algeria.  

PubMed

Antimicrobial properties of plants essential oils have been investigated in order to suggest them as potential tools to overcome the microbial drug resistance and the increasing incidence of food borne diseases problems. The aim of this research is to study the antibacterial and antifungal effects of four traditional plants essential oils, Ruta angustifolia, Ruta chalepensis, Ruta graveolens and Ruta tuberculata, against standard bacterial and fungal strains. The chemical compounds of the oils were examined by GC/MS. Results revealed a powerful antifungal activity against filamentous fungi. Aspergillus fumigatus and Cladosporium herbarum are the most sensitive strains to these oils with MIC values less than 3.5 ?g ml(-1) for certain oils, reaching 7.8 ?g ml(-1) for other. GC/MS essay exhibited ketones as the most abundant constituent of these oils except for R. tuberculata essential oil which has a completely different composition, monoterpenes alcohols being the most abundant. These compositions explain their potential antifungal activity. PMID:23768355

Haddouchi, Farah; Chaouche, Tarik Mohammed; Zaouali, Yosr; Ksouri, Riadh; Attou, Amina; Benmansour, Abdelhafid

2013-11-01

421

Chemical and isotopic composition of water from thermal springs and mineral springs of Washington  

USGS Publications Warehouse

Water from thermal springs of Washington range in chemical composition from dilute NaHC03, to moderately saline C02-charged NaHC03-Cl waters. St. Martin 's Hot Spring which discharges a slightly saline NaCl water, is the notable exception. Mineral springs generally discharge a moderately saline C02-charged NaHC03-Cl water. The dilute Na-HC03 waters are generally associated with granite. The warm to hot waters charged with C02 issue on or near the large stratovolcanoes and many of the mineral springs also occur near the large volcanoes. The dilute waters have oxygen isotopic compositions which indicate relatively little water-rock exchange. The C02-charged waters are usually more enriched in oxygen-18 due to more extensive water-rock reaction. Carbon-13 in the C02-charged thermal waters is more depleted (-10 to -12 permil) than in the cold C02-charged soda springs (-2 to -8 permil) which are also scattered throughout the Cascades. The hot and cold C02-charged waters are supersaturated with respect to CaC03, but only the hot springs are actively depositing CaC03. Baker, Gamma, Sulphur , and Ohanapecosh seem to be associated with thermal aquifers of more than 100C. (USGS)

Mariner, R.H.; Presser, T.S.; Evans, W.C.

1982-01-01

422

Chemical compositional, biological, and safety studies of a novel maple syrup derived extract for nutraceutical applications.  

PubMed

Maple syrup has nutraceutical potential given the macronutrients (carbohydrates, primarily sucrose), micronutrients (minerals and vitamins), and phytochemicals (primarily phenolics) found in this natural sweetener. We conducted compositional (ash, fiber, carbohydrates, minerals, amino acids, organic acids, vitamins, phytochemicals), in vitro biological, and in vivo safety (animal toxicity) studies on maple syrup extracts (MSX-1 and MSX-2) derived from two declassified maple syrup samples. Along with macronutrient and micronutrient quantification, thirty-three phytochemicals were identified (by HPLC-DAD), and nine phytochemicals, including two new compounds, were isolated and identified (by NMR) from MSX. At doses of up to 1000 mg/kg/day, MSX was well tolerated with no signs of overt toxicity in rats. MSX showed antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay) and anti-inflammatory (in RAW 264.7 macrophages) effects and inhibited glucose consumption (by HepG2 cells) in vitro. Thus, MSX should be further investigated for potential nutraceutical applications given its similarity in chemical composition to pure maple syrup. PMID:24983789

Zhang, Yan; Yuan, Tao; Li, Liya; Nahar, Pragati; Slitt, Angela; Seeram, Navindra P

2014-07-16

423

Chemical composition of the essential oils of Rhodiola rosea L. of three different origins  

PubMed Central

Rhodiola rosea L. (Crassulaceae), or “rose root” is a perennial herbaceous plant, distributed in the Northern Hemisphere. Pharmacological studies have shown that R. rosea exhibits different biological activities – antioxidant, antidepressant, anticancer, etc. The aim of this study was to compare the chemical composition of essential oils from rhizomes of three commercial samples of R. rosea originated from Bulgaria (sample 1), China (sample 2) and India (sample 3). The oils were analyzed by GC and GC-MS. Thus, the main volatile component in the Bulgaria and Chinese R. rosea was geraniol, followed by myrthenol in sample 1 or octanol in sample 2. Phenethylalcohol was a principal constituent in the Indian oil. Myrtenol and octanol were in significant amounts too. Aliphatic hydrocarbons were characteristic of the latter sample. It is notable that cinnamyl alcohol, which was present in large concentration in Bulgarian sample, was not detected in the other two samples. The obtained results showed considerable differences in the composition of the studied three origins of R. rosea. PMID:21120024

Evstatieva, Ljuba; Todorova, Milka; Antonova, Daniela; Staneva, Jordanka

2010-01-01

424

Photothermal method for in situ microanalysis of the chemical composition of coal samples  

DOEpatents

Successive minute regions (13) along a scan path on a coal sample (11) are individually analyzed, at a series of different depths if desired, to determine chemical composition including the locations, sizes and distributions of different maceral inclusions (12). A sequence of infrared light pulses (17) of progressively changing wavelengths is directed into each minute region (13) and a probe light beam (22) is directed along the sample surface (21) adjacent the region (13). Infrared wavelengths at which strong absorption occurs in the region (13) are identified by detecting the resulting deflections (.phi.) of the probe beam (22) caused by thermally induced index of refraction changes in the air or other medium (19) adjacent the region (13). The detected peak absorption wavelengths are correlated with known characteristic peak absorption wavelengths of specific coal constituents to identify the composition of each such minute region (13) of the sample (11). The method enables rapid, convenient and non-destructive analyses of coal specimens to facilitate mining, processing and utilization of coals.

Amer, Nabil M. (Berkeley, CA)

1986-01-01

425

Chemical composition and biological activities of Tunisian Cupressus arizonica Greene essential oils.  

PubMed

The chemical composition of the essential oils obtained by hydrodistillation of leaves, stems, and female cones of Cupressus arizonica Greene, grown in Tunisia, was studied by GC-FID and GC/MS analyses. Altogether, 62 compounds were identified, 62 in the leaf oil, 19 in the cone oil, and 24 in the stem oil. The cone and stem oils were mainly composed by monoterpene hydrocarbons (96.6 and 85.2%, resp.). In the leaf oil, the total sesquiterpene fraction constituted 36.1% and that of the monoterpene hydrocarbons 33.8% of the total oil composition. The three oils were evaluated for their in vitro herbicidal activity by determining their influence on the germination and the shoot and root growth of the four weed species Sinapis arvensis L., Lolium rigidum Gaudin, Trifolium campestre Schreb., and Phalaris canariensis L. At the highest doses tested (0.8 and 1.0?mg/ml), the leaf essential oil inhibited either totally or almost completely the seed germination and the shoot and root growth of S. arvensis and T. campestre. The oils were also tested for their antifungal activity; however, their effects on the fungal growth were statistically not significant. PMID:24443435

Ismail, Amri; Mancini, Emilia; De Martino, Laura; Hamrouni, Lamia; Hanana, Mohsen; Jamoussi, Bassem; Gargouri, Samia; Scognamiglio, Mariarosa; De Feo, Vincenzo

2014-01-01

426

Interactive effects of chemical and biological controls on food-web composition in saline prairie lakes  

PubMed Central

Salinity is restricting habitatability for many biota in prairie lakes due to limited physiological abilities to cope with increasing osmotic stress. Yet, it remains unclear how salinity effects vary among major taxonomic groups and what role other environmental parameters play in shaping food-web composition. To answer these questions, we sampled fish, zooplankton and littoral macroinvertebrates in 20 prairie lakes (Saskatchewan, Canada) characterized by large gradients in water chemistry and lake morphometry. We showed that salinity thresholds differed among major taxonomic groups, as most fishes were absent above salinities of 2 g L-1, while littoral macroinvertebrates were ubiquitous. Zooplankton occurred over the whole salinity range, but changed taxonomic composition as salinity increased. Subsequently, the complexity of fish community (diversity) was associated with large changes in invertebrate communities. The directional changes in invertebrate communities to smaller taxa indicated that complex fish assemblages resulted in higher predation pressure. Most likely, as the complexity of fish community decreased, controls of invertebrate assemblages shifted from predation to competition and ultimately to productivity in hypersaline lakes. Surprisingly, invertebrate predators did not thrive in the absence of fishes in these systems. Furthermore, the here identified salinity threshold for fishes was too low to be a result of osmotic stress. Hence, winterkill was likely an important factor eliminating fishes in low salinity lakes that had high productivity and shallow water depth. Ultimately, while salinity was crucial, intricate combinations of chemical and biological mechanisms also played a major role in controlling the assemblages of major taxonomic groups in prairie lakes. PMID:23186395

2012-01-01

427

Spark plasma sintering of tungsten-yttrium oxide composites from chemically synthesized nanopowders and microstructural characterization  

NASA Astrophysics Data System (ADS)

Nano-crystalline W-1%Y 2O 3 (wt.%) powder was produced by a modified solution chemical reaction of ammonium paratungstate (APT) and yttrium nitrate. The precursor powder was found to consist of particles of bimodal morphology i.e. large APT-like particles up to 20 ?m and rectangular yttrium containing ultrafine plates. After thermal processing tungsten crystals were evolved from W-O-Y plate like particles. spark plasma sintering (SPS) was used to consolidate the powder at 1100 and 1200 °C for different holding times in order to optimize the sintering conditions to yield high density but with reduced grain growth. Dispersion of yttrium oxide enhanced the sinterability of W powder with respect to lanthanum oxide. W-1%Y 2O 3 composites with sub-micron grain size showed improved density and mechanical properties as compared to W-La 2O 3 composites. Sample sintered in two steps showed improved density, due to longer holding time at lower temperature (900 °C) and less grain growth due to shorter holding time at higher temperature i.e. 1 min at 1100 °C.

Yar, M. A.; Wahlberg, Sverker; Bergqvist, Hans; Salem, H. G.; Johnsson, Mats; Muhammed, Mamoun

2011-05-01

428

Some Chemical Compositional Changes in Miscanthus and White Oak Sawdust Samples During Torrefaction  

SciTech Connect

Torrefaction tests on miscanthus and white oak sawdust were carried out in a bubbling sand bed reactor to see the effect of temperature and residence time on the chemical composition. Process conditions for miscanthus and white oak saw dust are 250–350°C and 30–120 minutes, and 220 and 270°C and 30 minutes, respectively. Composition of the torrefied samples studied includes moisture content and moisture-free carbon (%), hydrogen (%), nitrogen (%), sulfur (%), and volatiles. Torrefaction at 250°C and a residence time of 30 minutes resulted in a significant decrease in moisture—about 82.68%—but the other components, C, H, N, S, and V, changed only marginally. Increasing the torrefaction temperature to 350°C and residence time to 120 minutes further reduced the moisture to a final value of 0.54% (a 93.2% reduction compared to the original) and also resulted in a significant decrease in the other components, H, N, and V, by 58.29%, 14.28%, and 70.45%, respectively. The carbon content at 350°C and 120 minutes increased by about 4% and sulfur values were below detection limits. The H/C ratio decreased with an increase in torrefaction temperature, where a minimum value of 0.6 was observed at 350°C and 120 minutes. The regression equations developed with respect to torrefaction temperature and times have adequately described the changes in chemical composition based on r2 value. The surface plots developed based on the regression equations indicate that torrefaction temperatures of 300–350°C and residence times of 30–120 minutes can help increase carbon content to >49.4% and reduce moisture, nitrogen, volatile, and the H/C ratio from 1.13 to 0.6 %, 0.27 to 0.23 %, 79 to 23 %, and 1.3 to 0.6%, respectively. Torrefaction studies on white oak sawdust (woody biomass) at 220 and 270°C for 30 minutes indicated a similar trend where moisture, volatiles, hydrogen, and nitrogen decreased with increased torrefaction temperature from initial values of 8.53%, 80.75%, 5.91% and 0.17% to 1.79%, 66.31%, 4.67%, 0.16%, respectively; carbon content increased from 50.28 to 53.10%.

Jaya Shankar Tumuluru; Richard D. Boardman; Christopher T. Wright; J. Richard Hess

2012-10-01

429

All-year-round aerosol chemical composition at Dome C, Antarctica  

NASA Astrophysics Data System (ADS)

Since 2005, continuous, all-year-round aerosol sampling was carried out at Dome C (Central East Antarctica, 3233 m a.s.l., about 1100 km far from the coastline), in the framework of "Station Concordia" project, an Italian PNRA - French IPEV joint program. Size-segregated aerosol samples were collected in summer and winter periods by using different low- and medium-volume systems, including pre-selected cut-off samplers (with PM10, PM2.5 and PM1 cut-off heads) and multi-stage (Andersen 8-stage and Dekati 4-stage) impactors. Sampling resolution and volumes ranged from 1 day to 1 month and from 2.3 to 12 m3/h, respectively. Aerosol study at Dome C is expected improving our knowledge on present-day source intensity, transport efficiency and pathways (including stratosphere-troposphere interchanges) of particles reaching internal sites of Antarctica. Besides, more detailed information on atmosphere-snow interactions, including depositional and post-depositional processes, as well as the effect of sublimation/condensation processes on snow surface, will be used for improving the reconstruction of past atmosphere composition from ice core chemical stratigraphies (EPICA Dome C ice core). Here we report major results from the chemical composition of the Antarctic background aerosol reaching Dome C, pointing out the seasonal pattern and the temporal trend of some ionic components used as tracers of sea spray, marine biogenic and crustal emissions. Oxidised sulfur compounds are assumed to affect the climate system by influencing the Earth's radiative budget, both directly (solar light scattering) and indirectly (acting as cloud condensation nuclei). Among these compounds, methanesulphonic acid (MSA) and H2SO4 (arising from the atmospheric oxidation of phytoplanktonic dimethylsulphide - DMS), are considered the best tracers of marine productivity. Their use as reliable markers of oceanic biogenic emissions is hindered by poorly known mechanisms (temperature and photochemistry induced) controlling the MSA-H2SO4 ratio from DMS. Since, in summer, DMS in route toward central Antarctica is subjected to larger atmospheric concentrations of OH (and/or BrO) radical, lower temperatures and lower humidity, all conditions promoting the preferential H2SO4 formation, non-sea-salt sulphate is assumed to be the most