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1

Computing Equilibrium Chemical Compositions  

NASA Technical Reports Server (NTRS)

Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

Mcbride, Bonnie J.; Gordon, Sanford

1995-01-01

2

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

3

Aqueous chemical wash compositions  

SciTech Connect

This patent describes an aqueous, substantially unfoamed chemical wash composition having properties making it suitable for use as a pre-flush in well cementing operations and/or for removal of drilling mud from a borehole at a temperature of from about 150/sup 0/F to about 270/sup 0/F, the wash a. being predominantly composed of water, b. containing an active surfactant component comprising a combination of (1) from about 0.1 to about 1.5 weight percent (total weight basis) of a water soluble anionic surfactant; (2) from about 0.1 to about 1.5 weight percent (total weight basis) of a nonionic surfactant; and (3) from about 0.05 to about 0.54 weight percent (total weight basis) of at least one water soluble amphoteric surfactant, and c. having dispersed therein a heterogeneous mixture of distinct particles comprising both a first particulate oil soluble resin which is friable and a second particulate oil soluble resin which is pliable and where the size of the friable resin particles ranges from about 0.5 to about 300 microns and the size of the pliable resin particles ranges from about 0.05 to about 30 microns. The amount of the friable-pliable resin mixture is sufficient to impart effective fluid loss control to the chemical wash composition.

Bannister, C.E.

1987-07-21

4

Method of forming a chemical composition  

DOEpatents

A method of forming a chemical composition such as a chemical hydride is described and which includes the steps of selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of hydrogen; and exposing the selected composition to an amount of ionizing radiation to encourage the changing of the chemical bonds of the selected composition, and chemically reacting the selected composition with the source of hydrogen to facilitate the formation of a chemical hydride.

Bingham, Dennis N. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID); Klingler, Kerry M. (Idaho Falls, ID); Zollinger, William T. (Idaho Falls, ID); Wendt, Kraig M. (Idaho Falls, ID)

2007-10-09

5

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

6

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.

7

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

8

Chemical Composition of Martian Rocks  

NASA Astrophysics Data System (ADS)

In situ analyses of martian surface rocks (and soils) provided data about the chemical composition of several landing sites. One of the used techniques is the alpha-induced x-ray emission applied by the Alpha Particle X-Ray Spectrometer (APXS) onboard the current Mars Exploration Rovers (MER) Spirit and Opportunity and onboard the preceding Mars Pathfinder Rover Sojourner (MPF Mission). These measurements encompass the determination of major, minor, and (for the MER APXS) trace elements, such as Ni, Zn, and Br, as well as Cu, Pb, Sr, Y, Ga, and Ge. The obtained data indicate a remarkable compositional difference between the rocks at the different landing sites, whereas most soils including those measured by the Viking landers are chemically similar. Initially, the only chemical data of Mars were obtained by the study of a class of meteorites that turned out to be martian, which was furthermore confirmed by the discovery of a rock (by rover Opportunity) that is chemically related to those meteorites. The rocks at the Pathfinder landing site turned out to be richer in Si and K than the martian meteorites and all rocks encountered at the MER sites. At Gusev crater (the first MER landing site), two geological regions were encountered along the rover Spirit's traverse: the plains and the hills. Rocks in the plains resemble primitive basalts, while rocks located in the Columbia Hills revealed different types. Several rock classes could be cataloged based on their chemical composition. Most of the hills rocks are significantly weathered and enriched in mobile elements, such as P, Zn, S, Cl, and Br. On the other hand, a suite of ultramafic rocks was discovered for the first time on Mars. The rocks at Meridiani Planum (the second MER landing site) are salt-rich siliciclastic sediments. All rocks showed much higher S contents than the soils. High concentrations of Cl and Br were also discovered at various samples. Huge quantities of spherules were found on top of soils and outcrops along the rover's traverse. APXS measurements revealed that these spherules contain high amounts of iron that is mainly present as the mineral hematite (determined by Mössbauer spectrometry). The formation of hematite is typically, but not exclusively, an indicator for aqueous activities under oxidizing conditions. The in situ measurements at both MER landing sites point to a variety of sedimentary processes and various types of alteration processes; hence, they show clear evidence of ancient aqueous environments that discontinued long time, ago. The combination of in situ measurements and element correlations obtained by the martian meteorites implies an ancient basaltic crust with high abundances of incompatible elements (K, Rb, Nd, U, and Th) and volatile elements (S, Cl). Compared to the Earth's mantle, the martian mantle contains about twice as much Fe, is richer in moderately volatile elements like K, and has a much higher abundance of phosphorus. In conjunction with chemical data obtained from orbit, such as gamma-ray spectrometry carried out by the Mars Odyssey spacecraft, a global estimation of the composition of the martian surface is obtained and, furthermore, crustal composition can be derived.

Brueckner, J.

2007-05-01

9

The Chemical Composition of Some Texas Soils.  

E-print Network

TEXAS AGRICULTURAL ESPERlMENT STATIONS. ______-_________- _-__---- - -. - _ _._ __ BULLETlN NO. 100. Chemical Section, Dec., 1907. The Chemical Composition of Some Texas Soils BY G. S. FRAPS, 'Ph. D., Chemist. POSTOFFICE COLLEGE STATION.... The postoffice address is College, Station, Texas. Reports and bulletins are sent free upon application to the Director. THE CHEMICAL COMPOSITION OF SOME TEXAS SOILS. BY G. S. FRAPS. This bulletin is a popular account of a study of a nnmber of Texas soils...

Fraps, G. S. (George Stronach)

1907-01-01

10

Chemical composition of Earth-like planets  

E-print Network

Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous phase. The results of the semi-analytical model (final distributions of embryos and planetesimals) are used as initial conditions to develope N-body simulations that compute the post-oligarchic formation of terrestrial-type planets. The results of our simulations show that the chemical composition of the planets that remain in the habitable zone has similar characteristics to the chemical composition of the Earth. However, exist differences that can be associated to the dynamical environment in which they were formed.

Ronco, M P; Marboeuf, U; Alibert, Y; de Elía, G C; Guilera, O M

2015-01-01

11

Original article Anatomy and chemical composition  

E-print Network

. echinata, P. taeda, P. palustris and P. rigida, have been made [7, 8] and data on pine bark chemicalOriginal article Anatomy and chemical composition of Pinus pinea L. bark Elsa Nunesa Teresa Quilhób 1998; accepted 23 March 1999) Abstract - The secondary phloem of Pinus pinea L. bark has sieve cells

Paris-Sud XI, Université de

12

The Chemical Composition of Maple Syrup  

ERIC Educational Resources Information Center

Maple syrup is one of several high-sugar liquids that humans consume. However, maple syrup is more than just a concentrated sugar solution. Here, we review the chemical composition of maple syrup. (Contains 4 tables and 1 figure.)

Ball, David W.

2007-01-01

13

Acceptability and chemical composition of bread from beniseed composite flour  

Microsoft Academic Search

Reports a study to determine the suitability of beniseed for bread making as well as the chemical composition and acceptability of the bread among Nigerian bread consuming population. Three bread samples were developed from wheat, beniseed, and cassava composite flour using the formulae 85:10:5, 80:15:5 and 75:25:5. Baking characteristics, chemical composition and acceptability tests were carried out on the samples

Wasiu A. O. Afolabi; Clara R. B. Oguntona; Bilkisu B. Fakunmoju

2001-01-01

14

Lunar Skylights and Their Chemical Compositions  

NASA Astrophysics Data System (ADS)

In 2009, the Japanese orbiter, SELenological and Engineering Explorer (SELENE) discovered a skylight on the near side of the moon. Skylights are collapsed ceilings of rilles, thought to be caused by moonquakes, meteoroids, or incomplete formation of these lava tube ceilings. Since then, NASA's Lunar Reconnaissance Orbiter has discovered two more skylights, also located on the near side of the moon. Previous research has shown that the physical characteristics of known rilles, can be used as indicators of the presence of yet undiscovered rille and lava dome locations across the lunar surface. We hypothesize that skylights have a signature chemical composition that is unique, and can be used to predict the location of additional skylights on the surface of the moon. For this study, we compared chemical composition data of the three mare sites containing skylights with the 21 mare sites without skylights. Using the software JMARS for the Moon, we compiled multiple datasets to measure the concentrations of 13 different chemical compounds including calcium, iron oxide, titanium dioxide, and thorium. We then conducted a two-tailed T-test of the data, which generated probability values for the mean differences across all 13 chemical compounds of the maria sites with skylights and the maria sites without skylights. Our results show that there is no statistical difference in chemical composition across all of the maria sites examined. Therefore, we conclude that chemical composition does not predict or indicate potential skylight locations on the moon. Further research on other skylight characteristics, for example depth and surrounding underground lava channels, may shed light on the relationships between mare and skylights locations. Three Skylight Locations Found on Lunar Surface 100m View of Mare Tranquilitatis Skylight

Wong, J.; Torres, J.; FitzHoward, S.; Luu, E.; Hua, J.; Irby, R.

2013-12-01

15

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

16

Aerogel composites using chemical vapor infiltration  

Microsoft Academic Search

A new method to produce novel composite materials based on the use of aerogels as a starting material is described. Using chemical vapor infiltration, a variety of solid materials were thermally deposited into the open pore structure of aerogel. The resulting materials possess new and unusual properties including photoluminescence, magnetism and altered optical properties. An important characteristic of this preparation

Arlon J. Hunt; Michael R. Ayers; Wanqing Cao

1995-01-01

17

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

18

Chemical Softening and Wear of Dental Composites  

Microsoft Academic Search

The purpose of this work was to determine the influence of chemical food-simulating liquids on the wear of various commercial dental composite restoratives. In many cases, pre-conditioning the restoratives in these liquids for one week produced swelling of the polymer matrix and considerable surface damage. The resulting degradation reduced the hardness and enhanced the wear as measured by a pin-and-disc

J. E. McKinney; W. Wu

1985-01-01

19

Titan's Interior Chemical Composition: A Thermochemical Assessment*  

NASA Astrophysics Data System (ADS)

We study the interior composition of Titan using thermal chemical equilibrium calculations that are valid to high pressures and temperatures. The equations of state are based on exponential-6 fluid theory and have been validated against experimental data up to a few Mbars in pressure and approximately 20000K in temperature. In addition to CHNO molecules, we account for multi-phases of carbon, water and a variety of metals such as Al and Fe, and their oxides. With these fluid equations of state, chemical equilibrium is calculated for a set of product species. As the temperature and pressure evolves for increasing depth in the interior, the chemical equilibrium shifts. We assume that Titan is initially composed of comet material, which we assume to be solar, except for hydrogen, which we take to be depleted by a factor 1/690. We find that a significant amount of nitrogen is in the form of n2, rather than nh3. Moreover, above 12 kbars, as is the interior pressure of Titan, a significant amount of the carbon is in the form of graphite, rather than co2 and ch4. We discuss the implications of these results for understanding the atmospheric and surface composition of Titan. • This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Howard, Michael; Zaug, J. M.; Khare, B. N.; McKay, C. P.

2007-10-01

20

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

21

Cometary Coma Chemical Composition (C4) Mission  

NASA Technical Reports Server (NTRS)

Cometary exploration remains of great importance to virtually all of space science. Because comets are presumed to be remnants of the early solar nebula, they are expected to provide fundamental knowledge as to the origin and development of the solar system as well as to be key to understanding of the source of volatiles and even life itself in the inner solar system. Clearly the time for a detailed study of the composition of these apparent messages from the past has come. A comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, is now being studied as a candidate for the new Discovery program. This mission is a highly-focussed and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission. The C4 mission will concentrate on measurements that will produce an understanding of the composition and physical makeup of a cometary nucleus. The core science goals of the C4 mission are 1) to determine the chemical, elemental, and isotopic composition of a cometary nucleus and 2) to characterize the chemical and isotopic nature of its atmosphere. A related goal is to obtain temporal information about the development of the cometary coma as a function of time and orbital position. The four short-period comets -- Tempel 1, Tempel 2, Churyumov-Gerasimenko, and Wirtanen -which all appear to have acceptable dust production rates, were identified as candidate targets. Mission opportunities have been identified beginning as early as 1998. Tempel I with a launch in 1999, however, remains the baseline comet for studies of and planning the C4 mission. The C4 mission incorporates two science instruments and two engineering instruments in the payload to obtain the desired measurements. The science instruments include an advanced version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX with a sample collection system, an X-ray Fluorescence Spectrometer and a Pyrolysis-Gas Chromatograph, and a simplified version of the Neutral Gas and Ion Mass Spectrometer (NIGMS). Both of these instruments have substantial heritage as they are based on those developed for the CRAF Mission. The engineering instruments include a simplified Comet Dust Environmental Monitor (SCODEM) and a navigational Camera, NAVCAM. While neither of the instruments will be permitted to establish science requirements, it is anticipated that significant science return will be accomplished Radio science will also be included.

Carle, Glenn C.; Clark, Benton C.; Knocke, Philip C.; OHara, Bonnie J.; Adams, Larry; Niemann, Hasso B.; Alexander, Merle; Veverka, Joseph; Goldstein, Raymond; Huebner, Walter; Morrison, David (Technical Monitor)

1994-01-01

22

Chemical composition of Pinus sibirica (Pinaceae).  

PubMed

Siberian pine (Pinus sibirica), also known as Siberian cedar pine and Siberian cedar, is an important plant that has been long used as a source of natural compounds and materials (wood, needles, soft resin, turpentine, colophony). Its chemical composition has been studied well enough; however, to our surprise, no articles that compile the phytochemical data have been published so far. Presumably, this is due to the fact that most of the studies were published in journals difficult to access and not indexed by search systems. This review, for the first time, presents a systematic compilation of available data of secondary metabolites occurring in the needles, shoots, bark, wood, seeds, and oleoresin of Pinus sibirica. PMID:25641836

Rogachev, Artem D; Salakhutdinov, Nariman F

2015-01-01

23

Establishing of chemical composition of printing ink.  

PubMed

The subject of the examinations was primarily court tax marks of 50 and 200 PLN, which were suspected not to be genuine. Both inks on the questioned marks as well as comparative genuine marks and inks sent by the manufacturer were analyzed. No information about their chemical composition was available from manufacturer. In the examinations, infrared (IR), visible, X-ray fluorescence, and Raman spectrometry were used. The examinations showed that inks and glue on the marks of both values were the same as samples of those sent by the manufacturer. Discrepancies in some results were observed probably due to contamination, that is, an accidental presence of the foreign substance on the surface (e.g., sweat, saliva while sticking the marks to the surface or physical handling of the documents). It was concluded that there are original (genuine) court tax marks. PMID:21361954

Zi?ba-Palus, Janina; Trzci?ska, Beata M

2011-05-01

24

Mechanical properties of polypropylene composites reinforced with chemically treated abaca  

Microsoft Academic Search

In the present study, abaca was chemically treated with benzene diazonium salt in order to improve in the mechanical properties of the abaca-PP composites. Both raw and treated abaca samples were utilized for the fabrication of the composites. The mechanical properties of the composites prepared from chemically treated abaca are found to increase substantially compared to those of untreated ones.

Mahbub Hasan

2009-01-01

25

Carbon Nano Tube Composites with Chemically Functionalized Plant Oils  

Microsoft Academic Search

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

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

2003-01-01

26

Glycemic Index and Chemical Composition of Traditional Omani Breads  

Microsoft Academic Search

This study evaluated the chemical composition and glycemic index (GI) of eight different types of traditional Omani breads made from wheat flour. Significant (P < 0.05) differences were observed in the proximate chemical composition, dietary fibre content, and gross energy value of these breads. The moisture, crude protein, total fat, ash, crude fibre and nitrogen free extract (NFE) contents ranged

Amanat Ali; Hussain Ali S Al-Nassri; Buthaina Al-Rasasi; Mohammad Shoaib Akhtar; Buthaina Saleh Al-Belushi

2010-01-01

27

Chemical composition and nature of the Tunguska cosmic body  

Microsoft Academic Search

The chemical composition of the mineral section of the Tunguska cosmic body (from the 1908 disaster) is studied using samples from a mass deposit cover in the central region of the fall area. It is found that the chemical composition is similar to that of comets, having a predominance of low-melting and volatile elements. The substance of this assumed comet,

S. P. Golenetskii; V. V. Stepanok; E. M. Kolesnikov; D. A. Murashov

1977-01-01

28

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

29

Origin and Bulk Chemical Composition of Mercury  

NASA Astrophysics Data System (ADS)

The planet Mercury is remarkable because its mean uncompressed density ˜5.3 g/cc implies a Fe-Ni mass content of ˜67%. This is more than twice the ˜32% metal fractions of Venus and Earth. This factor coupled with other marked chemical and isotopic differences between the four terrestrial planets points to the conclusion that each planet ?received the overwhelming majority of its mass from a narrow compositionally-distinct annulus of material around the Sun? (Drake & Righter 2002 Nature 416 39; Taylor & Scott 2001 in URL below). This situation finds an explanation within the Modern Laplacian theory of Solar system origin (Prentice 2001 Earth Moon & Planets 87 11; URL: www.lpi.usra.edu/meetings/mercury01). Here the planets condensed from a concentric family of circular gas rings shed by the proto-Solar cloud. The temperatures and mean orbit pressures of the gas rings scale with heliocentric distance r as T ~ 1/r0.9 and p ˜1/r4.0 respectively. At Mercury?s orbit T = 1640 K p= 0.16 bar and the three primary equilibrium condensates are Fe-Ni (67 %) gehlenite (26.1%) and spinel (4.1%). A simple 2-zone structural model of Mercury based on this mix has mean density 5.43 g/cc and axial moment-of-inertia coefficent C/MR2 = 0.325.

Prentice, Andrew J. R.; Jontof-Hutter, Daniel

2005-01-01

30

Mercury's Origin and Bulk Chemical Composition  

NASA Astrophysics Data System (ADS)

The planet Mercury is remarkable because its mean uncompressed density ~5.3 g/cc implies a Fe-Ni mass content of ~67%. This is more than twice the ~32% metal fractions of Venus and Earth. This factor coupled with other marked chemical and isotopic differences between the four terrestrial planets points to the conclusion that each planet ?received the overwhelming majority of its mass from a narrow compositionally-distinct annulus of material around the Sun? (Drake & Righter 2002 Nature 416 39; Taylor & Scott 2001 in URL below). This situation finds an explanation within the Modern Laplacian theory of Solar system origin (Prentice 2001 Earth Moon & Planets 87 11; URL: www.lpi.usra.edu/meetings/mercury01). Here the planets condensed from a concentric family of circular gas rings shed by the proto-Solar cloud. The temperatures and mean orbit pressures of the gas rings scale with heliocentric distance r as T ~ 1/r0.9 and p ~ 1/r4.0 respectively. At Mercury?s orbit T = 1640 K p= 0.16 bar and the three primary equilibrium condensates are Fe-Ni (67 %) gehlenite (26.1%) and spinel (4.1%). A simple 2-zone structural model of Mercury based on this mix has mean density 5.43 g/cc and axial moment-of-inertia coefficent C/MR2 = 0.325.

Prentice, Andrew J.; Jontof-Hutter, Daniel

31

Origin and Bulk Chemical Composition of Mercury  

NASA Astrophysics Data System (ADS)

The planet Mercury is remarkable because its mean uncompressed density ~5.3 g/cc implies a metal content of ~67% by mass. This is more than twice the ~32% metal contents of each of Venus and Earth. This factor coupled with other marked chemical and isotopic differences between the four terrestrial planets points to the conclusion that each planet received the overwhelming majority of its mass from narrow compositionally-distinct annuli of material around the Sun (Drake & Righter 2002 Nature 416 43; Taylor & Scott 2001 in URL below). This situation finds an explanation within the Modern Laplacian theory of Solar system origin (Prentice 2001 Earth Moon & Planets 87 11 URL: www.lpi.usra.edu/meetings/mercury01). Here the planets condensed from a concentric family of circular gas rings shed by the proto-Solar cloud. The temperatures and mean orbit pressures of the gas rings scale with heliocentric distance r as T ~ 1/r0.9 and p ~ 1/r4.0 respectively. At the orbit of Mercury T = 1640 K p = 0.16 bar and the 3 primary equilibrium condensates are Fe-Ni-Cr-Co-V (67.0%) gehlenite (26.1%) and spinel (4.1%). A simple 2-zone structural model of Mercury based on this mix has mean density 5.43 g/cc and axial moment-of-inertia coefficent 0.325

Prentice, Andrew J.; Jontof-Hutter, Daniel

32

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

33

Chemical composition and variability of cork from Quercus suber L  

Microsoft Academic Search

Summary The chemical composition of cork from Quercus suber L. was determined for virgin cork and for reproduction cork. Average chemical composition of virgin cork is: ash 0.7%, total extractives 15.3%, suberin 38.6%, lignin 21.7% and polysaccharides 18.2%. The carbohydrate composition shows that glucose represents 50.6% of all monosaccharides, xylose 35.0%, arabinose 7.0% and galactose and mannose, respectively, 3.6% and

H. Pereira

1988-01-01

34

Chemical composition of high resin petroleum tar  

Microsoft Academic Search

The data from physico-chemical methods (elemental analysis, IR, NMR spectroscopy, etc.) and integral structural analysis are used to calculate the average structural parameters and to determine structural-molecular models of compounds contained in commercial tar of West Siberian, Romashkino and Arlan petroleums. The high molar mass compounds of the petroleums examined were characterized by unique principles of structural-molecular organization of corresponding

O. G. Popov; I. A. Posadov; D. A. Rozental; L. A. Kornilova

1984-01-01

35

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

36

Conventional agro-composites from chemically modified fibres  

Microsoft Academic Search

The effect of chemical modification on the performance of agro-composites made from non-toxic chemically modified MDF fibres from oil palm empty fruit bunches and phenol formaldehyde as matrix were investigated. Four types of composite boards were produced (extracted; non-extracted; acetylated; propionylated) and mechanical and physical properties were compared accordingly. Evidence of modification was indicated by increased of weight and was

H. P. S. Abdul Khalil; A. M. Issam; M. T. Ahmad Shakri; R. Suriani; A. Y. Awang

2007-01-01

37

Chemical composition of high resin petroleum tar  

SciTech Connect

The data from physico-chemical methods (elemental analysis, IR, NMR spectroscopy, etc.) and integral structural analysis are used to calculate the average structural parameters and to determine structural-molecular models of compounds contained in commercial tar of West Siberian, Romashkino and Arlan petroleums. The high molar mass compounds of the petroleums examined were characterized by unique principles of structural-molecular organization of corresponding typical fragments, which include similar naphthene-aromatic condensed systems of five-to-six rings; the results explain the possibility of mutual transitions of high molar mass petroleum compounds as well as the katagenic transformations of petroleum during processing. 12 references, 8 tables.

Popov, O.G.; Posadov, I.A.; Rozental, D.A.; Kornilova, L.A.

1984-01-01

38

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

39

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

40

"Chemical" composition of the Quark Gluon Plasma  

NASA Astrophysics Data System (ADS)

In this article we discuss the issue of the quark to gluon ratio in the Quark Gluon Plasma (QGP). Our model to describe the QGP evolution is based on transport theory including the mean field dynamics described by a quasi-particle model.The last is able to take into account for the lattice QCD thermodynamics and implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as T approaches to the temperature of the phase transition Tc. We present first the tests performed in a fixed box to check that our code is able to reproduce the equilibrium ratio and then the results obtained for the simulations of ultra-Relativistic Heavy Ion Collisions (uRHIC's) at RHIC and LHC energies. We observe a rapid evolution from a gluon dominated initial state to a quark dominated plasma and we see that near Tc almost 80% of the particles composing the plasma are quarks. This has potentially a strong impact on several quantitative aspects of QGP probes and furnishes a justification to the coalescence hadronization model.

Scardina, Francesco; Colonna, Maria; Plumari, Salvatore; Greco, Vincenzo

2013-09-01

41

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

42

Fuel options from microalgae with representative chemical compositions  

SciTech Connect

Representative species of microalgae are examined with respect to their reported chemical compositions. Each species is analyzed under a variety of culture conditions, with the objective being to characterize an optimum mixture of fuel products (e.g., methane, ethanol, methylester) which should be produced by the particular species. Historically the emphasis has been on the entire algal cell mass. Using the reported chemical composition for the representative species under specific sets of growth conditions, some conclusions can be drawn about the preferred fuel product conversion routes that could be employed. 10 references, 7 figures, 12 tables.

Feinberg, D. A.

1984-07-01

43

The Chemical Composition of the Cotton Plant.  

E-print Network

collect at cotton gins are also fed. . A sunimarp of the chemistry of cotton up to 1896 is published in a book entitled "The Cotton Plant," published by the United States De- partment of Agricuiture. Analysis of cotton leaves, seeds. stems, and lint... in the experiments at the .substations on the plots from which the plants for analysis were taken. Table 2-Average percentage composition as dried for analysis. MINERAL COMPOSITION. Table 2 shows the average composition of the various parts of the cotton plant...

Fraps, G. S. (George Stronach)

1919-01-01

44

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

45

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

46

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

47

Chemical composition of Earth, Venus, and Mercury.  

PubMed

Model compositions of Earth, Venus, and Mercury are calculated from the premise that planets and chondrites underwent four identical fractionation processes in the solar nebula. Because elements of similar properties stay together in these processes, five constraints suffice to define the composition of a planet: mass of the core, abundance of U, and the ratios K/U, Tl/U, and FeO/(FeO + MgO). Complete abundance tables, and normative mineralogies, are given for all three planets. Review of available data shows only a few gross trends for the inner planets: FeO decreases with heliocentric distance, whereas volatiles are depleted and refractories are enriched in the smaller planets. PMID:16592930

Morgan, J W; Anders, E

1980-12-01

48

Chemical composition of Earth, Venus, and Mercury  

PubMed Central

Model compositions of Earth, Venus, and Mercury are calculated from the premise that planets and chondrites underwent four identical fractionation processes in the solar nebula. Because elements of similar properties stay together in these processes, five constraints suffice to define the composition of a planet: mass of the core, abundance of U, and the ratios K/U, Tl/U, and FeO/(FeO + MgO). Complete abundance tables, and normative mineralogies, are given for all three planets. Review of available data shows only a few gross trends for the inner planets: FeO decreases with heliocentric distance, whereas volatiles are depleted and refractories are enriched in the smaller planets. Images PMID:16592930

Morgan, John W.; Anders, Edward

1980-01-01

49

Cynara cardunculus L.: chemical composition and soda-anthraquinone cooking  

Microsoft Academic Search

This paper presents results about the determination of chemical composition of a new annual plant (Cynara cardunculus L. or Cardoon in English) growing in Portugal at experimental scale. Two raw materials were studied. The first one concerns over mature crops collected in 1996, whereas the second one was collected at the right time in 1997. The Klason lignin content of

A. Antunes; E. Amaral; M. N. Belgacem

2000-01-01

50

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

51

Chemical composition of some medicinal plant products of indigenous origin  

Microsoft Academic Search

Chemical compositions of leaves of neem (Azadirachta indica), sajna (Moringa oleifera), arjun (Terminalia arjuna), tulsi (Ocimum sanctum), turmeric (Curcuma longa); rhizomes of ginger (Zingiber officinale) and turmeric; fruits of amla (Emblica officinalis), haritaki (Terminalia chebula), bohera (Terminalia belerica) and bulbs of garlic (Allium sativum) of indigenous origin were determined. Proximate and mineral components (Calcium (Ca), Phosphorus (P), Sodium (Na), Potassium

S. Bhowmik; S. D. Chowdhury; M. H. Kabir; M. A. Ali

2008-01-01

52

Chemical composition, mineral content and cholesterol levels of some regular  

E-print Network

Note Chemical composition, mineral content and cholesterol levels of some regular and reduced from cow's milk, were analyzed for basic nutrients (water, protein, fat, ash and lactose), cholesterol-1 . Cholesterol strongly correlated with fat content and an increase in cholesterol/fat ratios

Boyer, Edmond

53

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

54

The chemical composition of the bark of Larix sibirica  

Microsoft Academic Search

In order to study the chemical composition of the bark of Larix sibirica Ldb. (Siberian larch), we ground 150 kg of the bark and took 2-kg samples, which were analyzed by known methods [1-2]. The content of ash materials, including sulfur and phosphorus, was determined by combustion, nitrogen by the Dumas method, and tannides, resins, and fats by aqueous ethanolic

N. D. Barabash; É. D. Levin

1970-01-01

55

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 ...

56

Chemical composition of sewage-grown Spirulina platensis  

Microsoft Academic Search

Summary Spirulina platensis has been grown in an outdoor pilot production unit, with an exposed surface area of 450 m2, on a medium consisting of raw domestic sewage supplemented with sodium bicarbonate and nitrate or urea fertilizer. The chemical composition and yield of the biomass grown on sewage-nitrate was comparable to that grown on synthetic medium. The protein content was

P. N. Saxena; M. R. Ahmad; R. Shyam; P. S. Misra

1982-01-01

57

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...

58

Chemical composition and bioactivity studies of Alpinia nigra essential oils  

Technology Transfer Automated Retrieval System (TEKTRAN)

Free radical scavenging, bactericidal and bitting deterrent properties of Alpinia nigra essential oils (EOs) were investigated in the present study. Chemical composition of the EOs were analyzed using GC-MS/GC-FID which revealed the presence of 63 constituents including ß-caryophyllene as major comp...

59

Composition and Thermodynamic Properties of Air in Chemical Equilibrium  

NASA Technical Reports Server (NTRS)

Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 degrees k and for pressures 10(-5) to 10 (plus 4) atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards. (author)

Moeckel, W E; Weston, Kenneth C

1958-01-01

60

Optimum conditions for composites fiber coating by chemical vapor infiltration  

Microsoft Academic Search

A combined analytical and numerical method is employed to optimize process conditions for composites fiber coating by chemical vapor infiltration. For a first-order deposition reaction, the optimum pressure yielding the maximum deposition rate at a preform center is obtained in closed form and is found to depend only on the activation energy of the deposition reaction, the characteristic pore size,

Stewart K. Griffiths; R. H. Nilson

1998-01-01

61

The chemical composition of luminous stars: problems or opportunities?  

NASA Astrophysics Data System (ADS)

The surface chemical composition of a luminous star changes as the star evolves. Spectroscopic definition of the changes may be used to test stellar evolutionary models. This essay discusses some of the observed and predicted changes in three different groups of luminous stars: hot massive stars, yellow supergiants, and luminous asymptotic giant branch stars.

Lambert, D. L.

62

The Chemical Composition of Texas Honey and Pecans  

E-print Network

TEXAS AGRICULTURAL EXPERIMENT STATION AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS W. B. BIZZELL, President BULLETIN NO. 272 JANUARY, 192 1 --- - DIVISION OF CHEMISTRY THE CHEMICAL COMPOSITION OF TEXAS HONEY AND PECANS *. - B. YOUNGBLOOD...~ted States Department of Agriculture. CONTENTS . PAGE Introduction ................................................ 5 .......................................... Methods of Analysis 5 ....................................... Flavor of Honey ........ : 5...

Fraps, G. S. (George Stronach)

1921-01-01

63

Increasing dissimilarity of water chemical compositions in a warmer climate  

E-print Network

showing an in-lake biological process­driven seasonality, such as nitrogen, pH, silica, and organic carbon strategies. Here a unique homogeneous data set of 1041 Swedish boreal lakes, sampled during three lake of the water chemical composition between lakes with increasing temperatures. The variability pattern

64

Physical and chemical composition of hospital waste.  

PubMed

For selecting the most efficient treatment method of hospital waste, the composition analysis is generally considered to be the fundamental information. Currently, there are few studies regarding the characteristics of hospital waste. This study evaluated the physical and elemental composition of the hospital waste at the National Taiwan University Hospital (NTUH). The results should help us design an incinerator for the treatment of infectious waste, plastic syringes, pathological waste, and kitchen waste. During the study period, the estimated daily waste generation rate at NTUH was 4,600 kg/day, which consisted of 4,100 kg/day noninfectious refuse, 340 kg/day infectious waste, 70 kg/day kitchen waste, 50 kg/day pathological waste, and 40 kg/day plastic syringes. The NTUH waste consisted of 99.02% combustible wastes and 0.97% noncombustible wastes by mass. The combustible wastes constituted paper (16.17%), textiles (9.77%), cardboard, wood, and leaves (1.12%), food waste (21.51%), and plastics (50.45%). The noncombustible waste included 0.40% metal and 0.57% glass. Furthermore, the analysis indicated that the wastes contained 38% moisture, 4% ashes, and 58% solid with an average heat value of 3,400 kcal/kg. From the elemental analysis, the dominant elements were found to be carbon (34%) and oxygen (15%). PMID:8478527

Li, C S; Jenq, F T

1993-03-01

65

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

66

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

67

The chemical composition of the pre-solar nebula  

NASA Technical Reports Server (NTRS)

The chemical composition of comets may reflect an origin in the molecular cloud which subsequently formed the solar nebula. The chemistry of different types of interstellar clouds is contrasted, including an inventory of molecular species detected in Orion and in TMC 1. The first astronomical detections of the J = (1-0) transition of HCS(+) and the J = (16-15) transition of HC5N and the first detection of SO2 in a cold dust cloud are reported.

Irvine, W. M.

1983-01-01

68

Fabrication of fiber reinforced ceramic composites by chemical vapor infiltration  

Microsoft Academic Search

Ceramic fiber-ceramic matrix composites were prepared using the chemical vapor deposition (CVD) process. Our major goal of significantly reducing the infiltration times was accomplished. We have conceived a process, fabricated hardware, and demonstrated on a laboratory scale a process which permits CVD infiltration of an SiC fibrous preform with either an SiâNâ or SiC matrix in 2 to 12 h.

A. J. Caputo; W. J. Lackey

1984-01-01

69

Chemical composition of a lipopolysaccharide from Legionella pneumophila  

Microsoft Academic Search

Lipopolysaccharide isolated from Legionella pneumophila (Phil. 1) was examined for chemical composition. The polysaccharide split off by mild acid hydrolysis contained rhamnose, mannose, glucose, quinovosamine, glucosamine and 2-keto-3-deoxyoctonate, in molar proportions 1.6:1.8:1.0:1.5:4.1:2.7. Heptoses were absent and glucose was probably mainly phosphorylated. The carbohydrate backbone of the lipid A part consisted of glucosamine, quinovosamine and glycerol, in the molar ratios 3.9:1.0:3.4,

Anders Sonesson; Erik Jantzen; Klaus Bryn; Lennart Larsson; Jan Eng

1989-01-01

70

Chemical Compositions of Oils from Several Wild Almond Species  

Microsoft Academic Search

Chemical compositions of oils extracted from three wild almond species [Amygdalus scoparia from Beyza, Iran (AZ); A. scoparia from Borazjan, Iran (AJ), and A. hausknechtii from the Firuzabad region, (AH)] and a domestic species, A. dulcis from Estahban, Iran (AD), as a reference, were investigated. Total oil content ranged from 44.4% in AJ to 51.4% in AD. Saponification\\u000a numbers were

Ali Moayedi; Karamatollah Rezaei; Sohrab Moini; Behnam Keshavarz

2011-01-01

71

Chemical composition of corals in Saudi Red Sea Coast  

Microsoft Academic Search

Three species of corals Stylophora pistillata, Lobophyllia corymbosa and Echinopora gemmacea were collected from Sharm Obhur to study their chemical composition. This information was important in the investigation of their metabolic pathways and their mode of feeding. The concentrations of amino acids in these species were 9.37, 21.35 and 3.09 mg·g?1 dry weight of coral respectively. Plant pigments were highest

Sultan S. Al-Lihaibi; Abdulmohsin A. Al-Sofyani; G. R. Niaz

1998-01-01

72

40 CFR 761.292 - Chemical extraction and analysis of individual samples and composite samples.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Chemical extraction and analysis of individual samples and composite samples. 761.292 ...6) § 761.292 Chemical extraction and analysis of individual samples and composite samples. Use...

2010-07-01

73

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

74

Application of near infrared spectroscopy to predict chemical composition and energy value  

E-print Network

Application of near infrared spectroscopy to predict chemical composition and energy value for determining the chemical composition and energy value of compound feeds for ruminants. We studied 80 samples equations were developed to determine chemical composition, gross energy (GE), dOM, energy digestibility (d

Paris-Sud XI, Université de

75

Chemical Composition of Rainwater in Córdoba City, Argentina  

NASA Astrophysics Data System (ADS)

Sampling and chemical analysis of rainwater has proved to be a useful technique for studying its chemical composition and provides a greater understanding of local and regional dispersion of pollutants and their potential impacts to ecosystems through deposition processes. Samples of rainwater were collected during 2009-2012, in Córdoba city, Argentina. Two kind of sampling were performed: event-specific and sequential. The objective of the first of these was to determine the chemical concentration of the total rain, while the objective of the second one was to analyze the variability of the chemical concentration during an individual rain event. The total volume of each sample was divided in halves. One half was filtered through 0.45 ?m membrane filter. After this, all the samples were reduced by evaporation to a final volume of 10 ml. The non-filtered samples were acidified and digested in accordance to the method 3050B of the Environmental Protection Agency (EPA) for acid digestion of sediments. Multi-elemental standard solutions in different concentrations were prepared by adequate dilutions. Gallium was added as an internal standard in all standard solutions and samples. Exactly 5 ?L of these solutions were deposited on acrylic supports. When these droplets were dried, Synchrotron Radiation Total Reflection X-Ray Fluorescence technique was used for determining the chemical elements. Spectra were analyzed with the AXIL package for spectrum analysis. Due to the intrinsic characteristics of the total reflection technique, the background of the measurements is significantly reduced and there are no matrix effects, therefore quantification can be obtained from the linear correlation between fluorescence intensity and the concentration of the element of interest. The elements quantified were S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, and Pb. For all of them a calibration curve was performed in order to quantify their concentrations on the samples. The results show that the average pH in city rainwater was pH=6.5; the elements found in the samples were S, Ca, Cu, Cr, Sr, P, Fe, Mn, Pb, K, Ti, V, Zn and the average concentrations of these elements were below the limits established by World Health Organization for drinking water, and show a high natural variability. The temporal evolution of inorganic ion concentration during rain events was analyzed and the scavenging coefficients were calculated and compared with data from literature. A comparison was made between the rainwater chemical composition and chemical composition in the aerosols scavenging during the rain. This study is the first in Córdoba city to analyze the chemical composition of rainwater and constitute a base for future comparison of variability in pH and elemental composition.

López, M. L.; Asar, M. L.; Ceppi, S.; Bürgesser, R. E.; Avila, E.

2013-05-01

76

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

77

Predicting hygroscopic growth using single particle chemical composition estimates  

NASA Astrophysics Data System (ADS)

Single 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

78

Chemical composition and temperature structure of Titan's stratosphere  

NASA Astrophysics Data System (ADS)

We have explored the thermal and chemical composition of Titan's atmosphere by combining Cassini CIRS recordings and the related ground - and space - based observations. The fulfillment of one Titanian year of space observations provides us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment. We find indication for a weakening of the temperature gradient with warming of the stratosphere and cooling of the lower mesosphere. In addition, we infer precise concentrations for the trace gases and their main isotopologues and find that the chemical composition in Titan's stratosphere varies significantly with latitude during the 6 years investigated here, with increased mixing ratios towards the northern latitudes. In particular, we monitor and quantify the amplitu de of a maximum enhancement of several gases observed at northern latitudes up to 50°N around mid-2009, at the time of the NSE. We find that this raise is followed by a rapid decrease in chemical inventory in 2010 probably due to a weakening north polar vortex with reduced lateral mixing across the vortex boundary. By comparing the Cassini/CIRS results from both the limb and the nadir observations with past V1 (1980) and ISO (1997)inferences we find indication for seasonal variations.

Coustenis, A.; Bampasidis, G.; Achterberg, R.; Lavvas, P.; Vinatier, S.; Nixon, C.; Jennings, D.; Teanby, N.; Flasar, F. M.; Orton, G.; Romani, P.; Carlson, R.; Guandique, E. A.

2013-09-01

79

Chemical composition of rocks and soils at Taurus-Littrow  

NASA Technical Reports Server (NTRS)

Seventeen soils and seven rock samples were analyzed for major elements, minor elements, and trace elements. Unlike the soils at previous Apollo sites, which showed little difference in composition at each collection area, the soils at Taurus-Littrow vary widely. Three soil types are evident, representative of (1) the light mantle at the South Massif, (2) the dark mantle in the valley, and (3) the surface material at the North Massif. The dark-mantle soils are chemically similar to those at Tranquillitatis. Basalt samples from the dark mantle are chemically similar although they range from fine to coarse grained. It is suggested that they originated from the same source but crystallized at varying depths from the surface.

Rose, H. J., Jr.; Cuttitta, F.; Berman, S.; Brown, F. W.; Carron, M. K.; Christian, R. P.; Dwornik, E. J.; Greenland, L. P.

1974-01-01

80

Chemical composition of HAL, an isotopically-unusual Allende inclusion  

NASA Technical Reports Server (NTRS)

Samples of hibonite, black rim, and portions of friable rim from an unusual Allende inclusion, named HAL, were analyzed by INAA and RNAA for 37 major, minor, and trace elements. An unusually low amount of Ce was found in HAL, although it otherwise was highly enriched in REE compared to C1 chondrites. HAL is also depleted in Sr, Ba, U, V, Ru, Os, and Ir relative to other refractory elements. It is concluded that the distribution of REE between hibonite and rims was established when hibonite and other refractory minerals were removed at slightly different temperatures from a hot, oxidizing gas in which they previously coexisted as separate grains. Possible locations for the chemical and mass dependent isotopic fractionation are considered to be in ejecta from the low temperature helium-burning zone of a supernova and in the locally oxidizing environment generated by evaporation of interstellar grains of near-chondritic chemical composition.

Davis, A. M.; Tanaka, T.; Grossman, L.; Lee, T.; Wasserburg, G. J.

1982-01-01

81

Titan's lakes chemical composition: sources of uncertainties and variability  

E-print Network

Between 2004 and 2007 the instruments of the CASSINI spacecraft discovered hydrocarbon lakes in the polar regions of Titan. We have developed a lake-atmosphere equilibrium model allowing the determination of the chemical composition of these liquid areas. The model is based on uncertain thermodynamic data and precipitation rates of organic species predicted to be present in the lakes and seas that are subject to spatial and temporal variations. Here we explore and discuss the influence of these uncertainties and variations. The errors and uncertainties relevant to thermodynamic data are simulated via Monte-Carlo simulations. Global Circulation Models (GCM) are also employed in order to investigate the possibility of chemical asymmetry between the south and the north poles, due to differences in precipitation rates. We find that mole fractions of compounds in the liquid phase have a high sensitivity to thermodynamic data used as inputs, in particular molar volumes and enthalpies of vaporization. When we combin...

Cordiera, D; Luninee, J I; Lebonnoisg, S; Rannouh, P; Lavvasf, P; Loboi, L Q; Ferreirai, A G M

2011-01-01

82

Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites  

SciTech Connect

This report documents experiments and analyses that have been done at the Idaho National Engineering and Environmental Laboratory (INEEL) to measure the steam chemical reactivity of two types of carbon fiber composites, NS31 and NB31, proposed for use at the divertor strike points in an ITER-like tokamak. These materials are 3D CFCs constituted by a NOVOLTEX preform and densified by pyrocarbon infiltration and heat treatment. NS31 differs from NB31 in that the final infiltration was done with liquid silicon to reduce the porosity and enhance the thermal conductivity of the CFC. Our approach in this work was twofold: (1) physical characterization measurements of the specimens and (2) measurements of the chemical reactivity of specimens exposed to steam.

Anderl, Robert Andrew; Pawelko, Robert James; Smolik, Galen Richard

2001-05-01

83

Chemical composition of HAL, an isotopically-unusual Allende inclusion  

NASA Astrophysics Data System (ADS)

Samples of hibonite, black rim, and portions of friable rim from an unusual Allende inclusion, named HAL, were analyzed by INAA and RNAA for 37 major, minor, and trace elements. An unusually low amount of Ce was found in HAL, although it otherwise was highly enriched in REE compared to C1 chondrites. HAL is also depleted in Sr, Ba, U, V, Ru, Os, and Ir relative to other refractory elements. It is concluded that the distribution of REE between hibonite and rims was established when hibonite and other refractory minerals were removed at slightly different temperatures from a hot, oxidizing gas in which they previously coexisted as separate grains. Possible locations for the chemical and mass dependent isotopic fractionation are considered to be in ejecta from the low temperature helium-burning zone of a supernova and in the locally oxidizing environment generated by evaporation of interstellar grains of near-chondritic chemical composition.

Davis, A. M.; Tanaka, T.; Grossman, L.; Lee, T.; Wasserburg, G. J.

1982-09-01

84

Determining the chemical composition of cloud condensation nuclei  

SciTech Connect

This second progress report describes the status of the project one and one-half years after the start. The goal of the project is to develop the instrumentation to collect cloud condensation nuclei (CCN) in sufficient amounts to determine their chemical composition, and to survey the CCN composition in different climates through a series of field measurements. Our approach to CCN collection is to first form droplets on the nuclei under simulated cloud humidity conditions, which is the only known method of identifying CCN from the background aerosol. Under cloud chamber conditions, the droplets formed become larger than the surrounding aerosol, and can then be removed by inertial impaction. The residue of the evaporated droplets represents the sample to be chemically analyzed. Two size functions of CCN particles are collected by first forming droplets on the large particles are collected by first forming droplets on the large CCN in a haze chamber at 100% relative humidity, and then activating the remaining CCN at 1% supersaturation in a cloud chamber. The experimental apparatus is a serious flow arrangement consisting of an impactor to remove the large aerosol particles, a haze chamber to form droplets on the remaining larger CCN, another impactor to remove the haze droplets containing the larger CCN particles for chemical analysis, a continuous flow diffusion (CFD) cloud chamber to form droplets on the remaining smaller CCN, and a third impactor to remove the droplets for the small CCN sample. Progress is documented here on the development of each of the major components of the flow system. Chemical results are reported on tests to determine suitable wicking material for the different plates. Results of computer modeling of various impactor flows are discussed.

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

1992-02-01

85

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

86

Chemical composition and antioxidant activity of Algerian propolis.  

PubMed

Chemical composition of propolis samples from north Algeria was characterized by chromatographic and spectroscopic analyses. High-performance liquid chromatorgaphy with diode-array detection (HPLC-DAD) fingerprint of the methanol extracts allowed the definition of two main types of Algerian propolis (AP) directly related to their secondary metabolite composition. Investigation of two representative types of AP by preparative chromatographic procedure and mass spectrometric (MS) and NMR techniques led to the identification of their main constituents: caffeate esters and flavonoids from an AP type rich in phenolic compounds (PAP) and labdane and clerodane diterpenes, together with a polymethoxyflavonol, from an AP type containing mainly diterpenes (DAP). Subsequently, two specific HPLC-MS/MS methods for detection of PAP and DAP markers were developed to study the chemical composition of propolis samples of different north Algerian regions. Antioxidant activity of AP samples was evaluated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay, and a significant free-radical scavenging effect was observed for propolis of the PAP series rich in polyphenols. PMID:23650897

Piccinelli, Anna Lisa; Mencherini, Teresa; Celano, Rita; Mouhoubi, Zina; Tamendjari, Azeddine; Aquino, Rita Patrizia; Rastrelli, Luca

2013-05-29

87

Chemical Composition of Wild-2 Dust Collected by Stardust  

NASA Astrophysics Data System (ADS)

The Stardust spacecraft collected dust from Comet Wild-2 in two forms: material distributed along tracks in aerogel capture cells and residue in impact craters. To analyze the chemical composition of these samples the tracks produced in the aerogel were extracted as keystones containing complete tracks. Twenty-six tracks were analyzed using an X-Ray Microprobe, providing x-ray fluorescence chemical analysis for elements having K-lines at energies high enough to permit escape from the overlying aerogel (S and the heavier elements, including the moderately-volatile trace elements Cu, Zn, and Ga). Two of these tracks were then split open, exposing the interior for analysis by TOF-SIMS (which allowed detection of the lighter elements, e.g., Mg and Al). Neither Si nor O could be determined for samples captured in the aerogel, since these are the major elements in the aerogel itself. The residue in craters in the Al-foil were analyzed by SEM-EDX and TOF-SIMS. The crater residues provide information on the important light elements (Mg and Si). By combining the results from the craters and the tracks, a comprehensive chemical analysis of the Wild-2 dust was possible. Preliminary Examination of the material indicates that: 1) For particles collected in the aerogel, a significant fraction of the incident mass is frequently deposited along the entry track, suggesting the individual Wild-2 dust particles that hit the aerogel were relatively weak aggregates. 2) The chemical composition of the terminal particle in the track is frequently significantly different from the composition of the material deposited along the track, 3) Most of the elements measured show variations in their Fe-normalized abundances of more than two orders-of-magnitude in both the terminal particles and the material deposited along track walls, indicating that the Wild-2 dust is compositionally heterogeneous at the size scale of the largest particles analyzed, not simply a well-mixed aggregate of sub-micron grains, 4) The mean content of the refractory, rock-forming elements (Mg, Ca, Si, Cr, Fe, and Ni) averaged over the whole tracks and/or the crater residues in the Wild-2 grains are approximately chondritic, and, 5) There is an apparent enrichment over CI in some of the moderately-volatile minor elements (Cu, Zn, and Ga) in the Wild-2 dust.

Flynn, G. J.

2006-12-01

88

IR spectroscopic study of the chemical composition of epiphytic lichens  

NASA Astrophysics Data System (ADS)

Changes in the chemical composition of lichens exposed to pollutants are investigated by means of FTIR spectroscopy. According to model experiments, alkyl nitrates, ammonium salts, amines, and sulfones develop in the lichen thallus through the action of ammonia and nitric and sulfuric acids. Spectroscopic data of modeling experiments enabled nitrogen- and sulfur-containing substances to be identified as the main air pollutants in the vicinity of a pig-breeding complex and information to be obtained on the content of the pollutants and their impact on the lichens.

Meysurova, A. F.; Khizhnyak, S. D.; Pakhomov, P. M.

2011-11-01

89

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

90

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

91

Chemical feasibility of lithium as a matrix for structural composites  

NASA Technical Reports Server (NTRS)

The chemical compatibility of lithium with tows of carbon and aramid fibers and silicon carbide and boron monofilaments was investigated by encapsulating the fibers in liquid lithium and also by sintering. The lithium did not readily wet the various fibers. In particular, very little lithium infiltration into the carbon and aramid tows was achieved and the strength of the tows was seriously degraded. The strength of the boron and silicon carbide monofilaments, however, was not affected by the liquid lithium. Therefore lithium is not feasible as a matrix for carbon and aramid fibers, but a composite containing boron or silicon carbide fibers in a lithium matrix may be feasible for specialized applications.

Swann, R. T.; Esterling, D. M.

1984-01-01

92

Chemical composition of Vernonia albicans essential oil from India.  

PubMed

The chemical composition of the hydro-distilled essential oil obtained from the flowering aerial parts of Vernonia albicans DC. (Asteraceae) was analyzed by gas chromatography equipped with a flame ionization detector (GC-FID) and gas chromatography coupled with a mass spectrometry (GC/MS). Thirty-nine compounds have been identified, representing 97.5% of the total oil. The major constituents were beta-caryophyllene (34.3%), gamma-amorphene (19.5%), 9-epi-beta-caryophyllene (6.9%), and a-pinene (6.9%). The oil was found to be rich in sesquiterpene hydrocarbons (73.9%). PMID:25230512

Joshi, Rajesh K

2014-07-01

93

Model atmospheres for cool stars. [varying chemical composition  

NASA Technical Reports Server (NTRS)

This report contains an extensive series of model atmospheres for cool stars having a wide range in chemical composition. Model atmospheres (temperature, pressure, density, etc.) are tabulated, along with emergent energy flux distributions, limb darkening, and information on convection for selected models. The models are calculated under the usual assumptions of hydrostatic equilibrium, constancy of total energy flux (including transport both by radiation and convection) and local thermodynamic equilibrium. Some molecular and atomic line opacity is accounted for as a straight mean. While cool star atmospheres are regimes of complicated physical conditions, and these atmospheres are necessarily approximate, they should be useful for a number of kinds of spectral and atmospheric analysis.

Johnson, H. R.

1974-01-01

94

Chemical Peels  

MedlinePLUS

... How to Choose the Best Skin Care Products Chemical Peels Uses for Chemical Peels Learn more about specific conditions where chemical ... damaged skin Sagging skin Wrinkles What is a chemical peel? A chemical peel is a technique used ...

95

A bond-topological approach to theoretical mineralogy: crystal structure, chemical composition and chemical reactions  

NASA Astrophysics Data System (ADS)

Here, I describe a theoretical approach to the structure and chemical composition of minerals based on their bond topology. This approach allows consideration of many aspects of minerals and mineral behaviour that cannot be addressed by current theoretical methods. It consists of combining the bond topology of the structure with aspects of graph theory and bond-valence theory (both long range and short range), and using the moments approach to the electronic energy density-of-states to interpret topological aspects of crystal structures. The structure hierarchy hypothesis states that higher bond-valence polyhedra polymerize to form the (usually anionic) structural unit, the excess charge of which is balanced by the interstitial complex (usually consisting of large low-valence cations and (H2O) groups). This hypothesis may be justified within the framework of bond topology and bond-valence theory, and may be used to hierarchically classify oxysalt minerals. It is the weak interaction between the structural unit and the interstitial complex that controls the stability of the structural arrangement. The principle of correspondence of Lewis acidity-basicity states that stable structures will form when the Lewis-acid strength of the interstitial complex closely matches the Lewis-base strength of the structural unit, and allows us to examine the factors that control the chemical composition and aspects of the structural arrangements of minerals. It also provides a connection between a structure, the speciation of its constituents in aqueous solution and its mechanism of crystallization. The moments approach to the electronic energy density-of-states provides a link between the bond topology of a structure and its thermodynamic properties, as indicated by correlations between average anion coordination number and reduced enthalpy of formation from the oxides for [6]Mg{/m [4]}Si n O( m+2 n) and MgSO4(H2O) n .

Hawthorne, Frank C.

2012-11-01

96

Long-term chemical composition and temperature variations on Titan  

NASA Astrophysics Data System (ADS)

Nine years after Cassini's Saturn orbit insertion, we look at the evolution of the thermal and chemical composition of Titan's atmosphere by combining Cassini CIRS recordings and the related ground- and space- based observations. The fulfillment of one Titanian year of space observations provides us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment. By comparing V1 (1980), ISO (1997) and Cassini (2010) we find that a reversal of composition near the equator from automnal equinox to vernal equinox (1996 min -2009 max), as well as some differences in polar enhancement at the same era as Voyager.

Coustenis, A.; Bampasidis, G.; Achterberg, R.; Lavvas, P.; Vinatier, S.; Nixon, C.; Jennings, D.; Teanby, N.; Flasar, F. M.; Orton, G.; Romani, P.; Carlson, R.; Guandique, E. A.

2013-09-01

97

Nanograined WC-Co Composite Powders by Chemical Vapor Synthesis  

NASA Astrophysics Data System (ADS)

Nanograined tungsten carbide (WC) Co composite powders were prepared by a chemical vapor synthesis (CVS) process that has previously been used for preparing the aluminides of titanium and nickel and other metallic and intermetallic powders at the University of Utah. To determine the optimum condition for producing nanograined WC-Co composite powders, the effects of carburization temperature, CH4 to WCl6 ratio, CH4 to H2 ratio, CoCl2 contents, and residence time of WC on the powder composition and particle size were investigated. The reduction and carburization of the vaporized chlorides by CH4-H2 mixtures produced nanograined WC and Co composite powder, which sometimes contained small levels of W2C, W, or the ? (Co3W3C) phase. The presence of these incompletely carburized phases can be tolerated because they can be fully carburized during the subsequent sintering process. These phases can also be fully carburized by a separate post-treatment. The products were characterized by using X-ray diffraction (XRD) and a transmission electron microscope (TEM). As a result, nanograined WC-Co composite with the particle size less than 30 nm was obtained.

Ryu, Taegong; Sohn, H. Y.; Han, Gilsoo; Kim, Young-Ugk; Hwang, Kyu Sup; Mena, M.; Fang, Zhigang Z.

2008-02-01

98

Medium resolution spectroscopy and chemical composition of Galactic globular clusters  

E-print Network

We used integrated-light medium-resolution spectra of six Galactic globular clusters and model stellar atmospheres to carry out population synthesis and to derive chemical composition and age of the clusters. We used medium-resolution spectra of globular clusters published by Schiavon et al. (2005), as well as our long-slit observations with the 1.93 m telescope of the Haute Provence Observatory. The observed spectra were fitted to the theoretical ones interactively. As an initial approach, we used masses, radii and log g of stars in the clusters corresponding to the best fitting isochrones in the observed color-magnitude diagrams. The computed synthetic blanketed spectra of stars were summed according to the Chabrier mass function. To improve the determination of age and helium content, the shape and depth of the Balmer absorption lines was analysed. The abundances of Mg, Ca, C and several other elements were derived. A reasonable agreement with the literature data both in chemical composition and in age of ...

Khamidullina, D A; Shimansky, V V; Davoust, E

2015-01-01

99

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

100

Chemical Changes  

NSDL National Science Digital Library

In this activity you will learn what a chemical change is. The first step to understanding chemical changes is to recognize the difference between chemical properties and physical properties. Click here for an example: Chemical and Physical Changes What are the signs of a chemical reaction occuring? Signs of Chemical Change What variables affect a chemical reaction? Variables ...

Mr. Jolley

2005-10-25

101

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

102

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

103

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

104

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

105

Photovoltaic Study of Chemically Derived Titanium-Doped Polythiophene Composites  

NASA Astrophysics Data System (ADS)

In the present work, titanium (Ti)-doped polythiophene (PTh) was synthesized by a chemical route using titanium chloride as oxidant. As-synthesized composites were further used for fabrication of photovoltaic (PV) cells with indium tin oxide/Ti-doped PTh/aluminum architecture. Structural, morphological, and optical analyses of as-synthesized composites were carried out through x-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence (PL) measurements. A broad peak was found in the PL spectra of the composites at around 480 nm, indicating high charge generation efficiency. Different PV parameters of the fabricated PV cells were measured at room temperature under incandescent light of 100 W/m2. The optimized PV cell exhibited short-circuit current (I sc) and open-circuit voltage (V oc) on the order of 176 ?A and 0.595 V, respectively. The values of I sc and V oc were used to compute the fill factor, which was found to be 0.521. The corresponding power conversion efficiency associated with the optimized cell was found to be 2.41%.

Takpire, S. R.; Waghuley, S. A.

2015-03-01

106

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

107

Thymus vulgaris essential oil: chemical composition and antimicrobial activity  

PubMed Central

The study was designed to determine the chemical composition and antimicrobial properties of the essential oil of Thymus vulgaris cultivated in Romania. The essential oil was isolated in a yield of 1.25% by steam distillation from the aerial part of the plant and subsequently analyzed by GC-MS. The major components were p-cymene (8.41%), ?-terpinene (30.90%) and thymol (47.59%). Its antimicrobial activity was evaluated on 7 common food-related bacteria and fungus by using the disk diffusion method. The results demonstrate that the Thymus vulgaris essential oil tested possesses strong antimicrobial properties, and may in the future represent a new source of natural antiseptics with applications in the pharmaceutical and food industry.

Borug?, O; Jianu, C; Mi?c?, C; Gole?, I; Gruia, AT; Horhat, FG

2014-01-01

108

Similarities in the chemical composition of carbonate groundwaters and seawater  

SciTech Connect

Fifty-four elements were quantified in spring waters emanating from carbonate rock in Ash Meadows, in southern Nevada, and in Death Valley, CA. The results show that the concentrations of many of the trace elements found in these groundwaters are remarkably close to those found in modern seawater. The concentrations of 26 of the elements in the spring waters and seawater are within a factor of 2; 14 more are within a factor of 10; 8 elements are enriched in the groundwater by more than a factor of 10; and 6 elements are depleted by more than a factor of 10. Similarities in the trace chemical composition of ancient seawater and modern seawater can be inferred from the fingerprint of trace elements found in these carbonate rock-source spring waters.

Hodge, V.F.; Stetzenbach, K.J.; Johannesson, K.H. [Univ. of Nevada, Las Vegas, NV (United States)] [Univ. of Nevada, Las Vegas, NV (United States)

1998-09-01

109

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

110

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 ...

111

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 ...

112

Trends in the chemical composition of lunar rocks and glasses  

Microsoft Academic Search

The paper presents a new method of multivariate statistics used to develop a new classification of the lunar glasses for each of eight soil samples using data from more than 2000 chemical analyses. The study of the homogeneous classes led to the determination of seven groups which were interpreted as the chemical equivalents of the seven main groups of lunar

A. I. Gavrishin; A. Coradini; M. Fulchignoni

1980-01-01

113

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

114

Flaxseed hull: Chemical composition and antioxidant activity during development.  

PubMed

Changes in the chemical composition and antioxidant activity of flaxseed hull during maturation were investigated. P129 hull variety was studied at four maturation stages (St1, St2, St3, and St4). Significant variation in proximate composition and flaxseed hull oil characteristics were observed. A significant increase in the carbohydrates content of the hull was observed during development. The main methyl esters were linolenic acid (48.95 - 51.52 %), oleic acid (20.27-23.41%) and linoleic acid (15.62-17.70%). The highest polyunsaturated fatty acids (PUFA) were found to be 67.14 % at the first stage of maturity (St1). Flaxseed hull oil was of good quality, containing an abundance of omega-3 essential fatty acids. The iodine value increased, while the saponification value of oil decreased during seed development. The decrease in ascorbic acid content was steady. The maximum level of total phenolic acid content (128.3 mg/100 g oil) was reached at 7 DAF. The antioxidant activity of oilseed was assessed by means of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Radical scavenging activity for green hull was 52.74% and mature hull was 69.32%. PMID:24919478

Herchi, Wahid; Al Hujaili, Abdullah D; Sakouhi, Faouzi; Sebei, Khaled; Trabelsi, Hajer; Kallel, Habib; Boukhchina, Sadok

2014-01-01

115

[Characteristics of chemical compositions of precipitation in Beijing].  

PubMed

Characteristics of chemical compositions of precipitation in Beijing were analyzed. The average value of pH was 5.19 from 2005 to 2009, showing stable characteristics of acidification with precipitation. The lowest annual average pH was 4. 87 in 2008 with the highest acidification frequency of 42% and 23% in Chegongzhuang and Daxing districts respectively. The inorganic ion concentrations declined in 5a, indicating an increasing improvement of air quality in Beijing. The concentrations of NH4+ and NO3- were found to increase and contributed to the high nitrogen amount in precipitation. Different seasons have influence on composition concentrations. Generally speaking, the ion concentrations in winter were higher that that in summer. SO4(2-) was the main factor responsible for the acidification of snow in winter, SO4(2-) and NO3- had similar contributions to the acidification of precipitation in summer. It was also found that the local pollutants of SO2, NO(x) and NH3 were major contributors to the acidification of precipitation in Beijing area, local geological conditions and long-distance transfers have important effects on the neutralization of the precipitation. PMID:21922802

Yang, Dong-Yan; Li, Xiu-Jinz; Chen, Yuan-Yuan; Zou, Ben-Dong; Lin, An-Guo

2011-07-01

116

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

117

CHEMICAL COMPOSITION OF EXHAUST PARTICLES FROM GAS TURBINE ENGINES  

EPA Science Inventory

A program was conducted to chemically characterize particulate emissions from a current technology, high population, gas turbine engine. Attention was focused on polynuclear aromatic compounds, phenols, nitrosamines and total organics. Polynuclear aromatic hydrocarbons (PAH) were...

118

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

119

Composite-Material Tanks with Chemically Resistant Liners  

NASA Technical Reports Server (NTRS)

Lightweight composite-material tanks with chemically resistant liners have been developed for storage of chemically reactive and/or unstable fluids . especially hydrogen peroxide. These tanks are similar, in some respects, to the ones described in gLightweight Composite-Material Tanks for Cryogenic Liquids h (MFS-31379), NASA Tech Briefs, Vol. 25, No. 1 (January, 2001), page 58; however, the present tanks are fabricated by a different procedure and they do not incorporate insulation that would be needed to prevent boil-off of cryogenic fluids. The manufacture of a tank of this type begins with the fabrication of a reusable multisegmented aluminum mandrel in the shape and size of the desired interior volume. One or more segments of the mandrel can be aluminum bosses that will be incorporated into the tank as end fittings. The mandrel is coated with a mold-release material. The mandrel is then heated to a temperature of about 400 F (approximately equal to 200 C) and coated with a thermoplastic liner material to the desired thickness [typically approxiamtely equal to 15 mils (approximately equal to 0.38 mm)] by thermal spraying. In the thermal-spraying process, the liner material in powder form is sprayed and heated to the melting temperature by a propane torch and the molten particles land on the mandrel. The sprayed liner and mandrel are allowed to cool, then the outer surface of the liner is chemically and/or mechanically etched to enhance bonding of a composite overwrap. The etched liner is wrapped with multiple layers of an epoxy resin reinforced with graphite fibers; the wrapping can be done either by manual application of epoxy-impregnated graphite cloth or by winding of epoxy-impregnated filaments. The entire assembly is heated in an autoclave to cure the epoxy. After the curing process, the multisegmented mandrel is disassembled and removed from inside, leaving the finished tank. If the tank is to be used for storing hydrogen peroxide, then the liner material should be fluorinated ethylene/propylene (FEP), and one or more FEP O ring(s) should be used in the aluminum end fitting(s). This choice of materials is dictated by experimental observations that pure aluminum and FEP are the only materials suitable for long-term storage of hydrogen peroxide and that other materials tend to catalyze the decomposition of hydrogen peroxide to oxygen and water. Other thermoplastic liner materials that are suitable for some applications include nylon 6 and polyethylene. The processing temperatures for nylon 6 are lower than those for FEP. Nylon 6 is compatible with propane, natural gas, and other petroleum-based fuels. Polyethylene is compatible with petroleum- based products and can be used for short-term storage of hydrogen peroxide.

DeLay, Thomas K.

2004-01-01

120

Chemical composition of inks of diverse marine molluscs suggests convergent chemical defenses.  

PubMed

Some marine molluscs, notably sea hares, cuttlefish, squid, and octopus, release ink when attacked by predators. The sea hare Aplysia californica releases secretions from the ink gland and opaline gland that protect individuals from injury or death from predatory spiny lobsters through a combination of mechanisms that include chemical deterrence, sensory disruption, and phagomimicry. The latter two mechanisms are facilitated by millimolar concentrations of free amino acids (FAA) in sea hare ink and opaline, which stimulate the chemosensory systems of predators, ultimately leading to escape by sea hares. We hypothesize that other inking molluscs use sensory disruption and/or phagomimicry as a chemical defense. To investigate this, we examined concentrations of 21 FAA and ammonium in the defensive secretions of nine species of inking molluscs: three sea hares (Aplysia californica, Aplysia dactylomela, Aplysia juliana) and six cephalopods (cuttlefish: Sepia officinalis; squid: Loligo pealei, Lolliguncula brevis, Dosidicus gigas; octopus: Octopus vulgaris, Octopus bimaculoides). We found millimolar levels of total FAA and ammonium in these secretions, and the FAA in highest concentration were taurine, aspartic acid, glutamic acid, alanine, and lysine. Crustaceans and fish, which are major predators of these molluscs, have specific receptor systems for these FAA. Our chemical analysis supports the hypothesis that inking molluscs have the potential to use sensory disruption and/or phagomimicry as a chemical defense. PMID:17393278

Derby, Charles D; Kicklighter, Cynthia E; Johnson, P M; Zhang, Xu

2007-05-01

121

Long-term chemical composition and temperature variations on Titan  

NASA Astrophysics Data System (ADS)

Nine years after Cassini's Saturn orbit insertion, we look at the evolution of the thermal and chemical composition of Titan’s atmosphere by combining Cassini CIRS recordings and the related ground- and space- based observations. In particular, we use Cassini/CIRS data from 2004-2013 to derive the temperature structure [1,2,7] and the neutral chemistry at latitudes between 50°S and 50°N [2]. The peak in abundance is observed around the northern spring equinox, with a rapid decrease after mid-2009, indicating that the vortex has shrunk. The fulfillment of one Titanian year of space observations provides us for the first time with the opportunity to evaluate the relative role of different physical processes in the long term evolution of this complex environment, as also reported by other studies [8-10]. By comparing V1 (1980), ISO (1997) and Cassini (2010) [2-6] data we find that a return to the 1980 abundance values is achieved for most molecules at all latitudes, indicative of the solar radiation being the dominating energy source at 10 AU, as for the Earth, in agreement with predictions by GCM and photochemical models. The few exceptions set important constraints. We show that wrt V1 the stratospheric chemical composition shows higher values near the northern fall equinox (near 1997) and lower ones at the spring equinox (near 2009). The cause could be spatial changes (due to Titan's inclination) in the energy input to Titan's atmosphere as a driver for changes in the advection patterns, circulation, etc which in turn provide a stronger variability in the latitudinal abundances of photochemical species after some time. References [1] Achterberg R., et al., Icarus, 211, 686-698, 2011. [2] Bampasidis et al., ApJ 760, 144, 8 p., 2012. [3] Coustenis, A., Bézard, B., Icarus,115, 126-140, 1995. [4] Coustenis, A., et al., Icarus, 161, 383-403, 2003. [5] Coustenis, A., et al., Icarus, 189, 35-62, 2007. [6] Coustenis, A., et al., Icarus, 207, 461-476, 2010. [7] Coustenis, A., et al., submitted. [8] Teanby, N., et al., Icarus, 193, 595-611, 2008. [9] Teanby, N., et al., Icarus, 193, 595-611, 2010. [10] Vinatier, S., et al., Icarus, 205, 559-570, 2010.

Coustenis, Athena; Bampasidis, G.; Achterberg, R.; Lavvas, P.; Nixon, C.; Jennings, D. E.; Teanby, N.; Michael, F. F.; Orton, G.; Vinatier, S.; Carlson, R. C.

2013-10-01

122

Effects of particle size distribution, surface area and chemical composition on Portland cement strength  

Microsoft Academic Search

The fineness of a Portland cement and its chemical composition are the key factors in determining cement strength characteristics. This paper describes a study of the relationship between cement particle size distribution and surface area, and the effects of size distribution, surface area and chemical composition on concrete strength. A new correlation between particle size distribution and surface area has

Y. M. Zhang; T. J. Napier-Munn

1995-01-01

123

Effect of chemical treatment on the tensile properties of short sisal fibre-reinforced polyethylene composites  

Microsoft Academic Search

The effect of chemical treatment on the tensile properties of sisal fibre-reinforced LDPE (low density polyethylene) composites was investigated. Treatments using chemicals such as sodium hydroxide, isocyanate, permanganate and peroxide were carried out to improve the bonding at the fibre polymer interface. The treatments enhanced the tensile properties of the composites considerably, but to varying degrees. The SEM (scanning electron

C. Pavithran

1996-01-01

124

Carbon\\/silicon carbide composites prepared by chemical vapor infiltration combined with silicon melt infiltration  

Microsoft Academic Search

In order to reduce processing costs and improve the thermal stability of three-dimensional carbon fiber-reinforced silicon carbide composites, a chemical vapor infiltration combined with silicon melt infiltration method was developed for fabricating composites. According to the size of the pores in the preform, chemical vapor infiltration (CVI) and silicon melt infiltration (SMI) were mainly used to infiltrate small pores between

Yongdong Xu; Laifei Cheng; Litong Zhang

1999-01-01

125

The Chemical Composition of Rainfall and Throughfall in Five Forest Communities: A Case Study  

E-print Network

Throughfall chemistry. Nutrient concentration . Nutrient flux . Enrichment ratio . Temperate forest . FortThe Chemical Composition of Rainfall and Throughfall in Five Forest Communities: A Case Study, comparative studies on the chemical composition of throughfall were carried out in five characteristic forest

126

The question about the chemical composition and nature of the Tunguska cosmic body  

Microsoft Academic Search

The chemical composition of the mineral section of the Tunguska cosmic body (from the 1908 disaster) is studied using samples from a mass deposit cover in the central region of the fall area. It is found that the chemical composition is similar to that of comets, having a predominance of low-melting and volatile elements. The substance of this assumed comet,

S. P. Golenetskii; V. V. Stepanok; E. M. Kolesnikov; D. A. Murashov

1978-01-01

127

To measure the chemical composition of a Near Earth Object  

NASA Astrophysics Data System (ADS)

Introduction. Scenarios for a Near Earth Object (NEO) rendezvous mission were discussed recently in Europe. Such a mission would address scientific questions about the initial conditions and evolutionary history of the solar nebula, as well as mitigation considerations to prevent impact with the Earth. In our opinion the measurement of the elemental composition and the distribution of volatiles in the shallow sub-surface are two of the key observations to be conducted, either from an orbiter or a lander. These measurements are also valuable for documentation (landing site candidates and sample context). This report is limited to the chemical composition, but we assume that remote and/or in-situ observations of physical characteristics, interior, morphology, mineralogy, and organic compounds will also be made as essential complements to achieve the mission scientific objectives. Scientific Interest. The analysis of the bulk composition addresses three fundamental aspects of the scientific mission: (1) the formation of the asteroid or the comet; (2) the evolution of the object; (3) the relation between the parent body and collected meteorites on Earth. Classification of an asteroid/comet can be based on its global composition (abundances of Mg, Si, Fe, Al, Ca, etc. along with its mineralogy), which bears the signature of the feeding zone where it formed. For example the K/U and K/Th ratios seem to increase with distance from the Sun (decreasing temperature). The hydrogen content is another measurable to study the distribution of volatiles in the Solar System. The surface composition is also the result of the degree of evolution of the object and of the interactions with its environment. Building a compositional map of the major elements is necessary to identify and characterize the processes that influenced the asteroid along its history. Finally, knowing the chemical composition will obviously help to relate the parent 1 body to meteorites. Ideally the measurement of specific isotopes, including O, C and those produced by the exposure to the cosmic rays, such as 38 Ar or 21 Ne, can pinpoint to the family of meteorites, but such measurements are challenging with restricted resources. Instrument Payload Options. To define the most appropriate instrument(s) in terms of scientific return and technical constraints, various solutions have been studied. For the orbiter this includes an X-ray spectrometer with a solar monitor, and a gamma-ray spectrometer with a neutron sensor. For a lander, it has been demonstrated that an active X-ray spectrometer gives outstanding results for very low resources. If mass is available in the frame of an ambitious mission, one can consider active experiments such as a laser-induced breakdown spectrometer, a mass spectrometer (needing sample manipulation, a laser ablation system, or an ion source), or evolved gas analyzers. It is very difficult however to baseline the use of active experiments from the orbiter (very close fly-bys) such as those on board the Phobos missions. On the one hand the main constraints on the lander are related to the resources (mass, power, volume) and possibly the need for target contact/manipulation. On the other hand the difficulties from the orbiter are the sensitivity to prioritized chemical elements and the mapping resolution (e.g. of the order of 1/10 of the altitude for X-rays, and equivalent to the altitude for gamma-rays). Remote-sensing experiments have been evaluated from that perspective; It is possible to estimate the accumulation time needed to reach enough precision: of the order of 1 h for X-rays and several hours for gamma-rays above each pixel (defined by the spatial resolution, see above). In a classical orbital mission scenario these numbers translate into several weeks of observations (more than 1 month). Lessons learned from previous missions (Apollo, Lunar Prospector, NEAR, Mars Odyssey, SMART-1) are also taken into account: the difficulty to monitor the solar activity for the X-rays, the low signal to noise ratio for the gamma-rays. Previous exper

Gasnault, 0.; Ball, A.; Biele, J.; D'Uston, C.; Forni, O.; Klingelhofer, G.; Maurice, S.; Ulamec, S.

128

Chemical milling  

Microsoft Academic Search

Chemical milling was used in removing excess material and reducing overall weight of metal parts. Chemical milling is discussed generally, describing the process, its applications, advantages and limitations, chemical milling solutions, maskants, and various other aspects of the chemical milling process. The effectiveness of chemical milling of specific materials such as aluminum, beryllium, magnesium, titanium, steel, and stainless steel alloys

J. W. Dini

1974-01-01

129

Chemical composition and antioxidant activities of Broussonetia papyrifera fruits.  

PubMed

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

130

An investigation into the chemical composition of alternative invertebrate prey.  

PubMed

The aim of this study was to determine the chemical composition of eight invertebrate species and evaluate their suitability as alternative prey. The species selected were rusty red cockroaches (Blatta lateralis), six-spotted cockroaches (Eublaberus distanti), Madagascar hissing cockroaches (Gromphadorhina portentosa), fruit flies (Drosophila melanogaster), false katydids (Microcentrum rhombifolium), beetles of the mealworm (Tenebrio molitor), and superworm beetles (Zophobas morio), as well as woodlice (Porcellio scaber). Dry matter (DM), crude protein, crude fat, neutral detergent fiber, acid detergent fiber, ash, macro and trace minerals, vitamins A and E, and carotenoid concentrations were quantified. Significant differences were found between species. Crude protein content ranged from 38 to 76% DM, fat from14 to 54% DM, and ash from 2 to 8% DM. In most species, calcium:phosphorus was low (0.08-0.30:1); however, P. scaber was an exception (12:1) and might prove useful as a dietary source of calcium for insectivores. Vitamin E content was low for most species (6-16?mg/kg DM), except for D. melanogaster and M. rhombifolium (112 and 110?mg/kg DM). The retinol content, as a measure of vitamin A activity, was low in all specimens, but varied greatly among samples (0.670-886?mg/kg DM). The data presented can be used to alter diets to better suit the estimated requirements of insectivores in captivity. Future research on the topic of composition of invertebrate prey species should focus on determination of nutrient differences owing to species, developmental stage, and diet. PMID:21442652

Oonincx, D G A B; Dierenfeld, E S

2012-01-01

131

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

132

Chemical composition and antibacterial activity of Gongronema latifolium  

PubMed Central

Chemical composition of Gongronema latifolium leaves was determined using standard methods. Aqueous and methanol G. latifolium extracts were tested against thirteen pathogenic bacterial isolates. Crude protein, lipid extract, ash, crude fibre and nitrogen free extractives obtained are: 27.2%, 6.07%, 11.6%, 10.8% and 44.3% dry matter respectively. Potassium, sodium, calcium, phosphorus and cobalt contents are 332, 110, 115, 125 and 116 mg/kg respectively. Dominant essential amino acids are leucine, valine and phenylalanine. Aspartic acid, glutamic acid and glycine are 13.8%, 11.9% and 10.3% respectively of total amino acid. Saturated and unsaturated fatty acids are 50.2% and 39.4% of the oil respectively. Palmitic acid makes up 36% of the total fatty acid. Extracts show no activity against E. faecalis, Y. enterolytica, E. aerogenes, B. cereus and E. agglomerans. Methanol extracts were active against S. enteritidis, S. cholerasius ser typhimurium and P. aeruginosa (minimum inhibitory concentration (MIC) 1 mg; zone of growth inhibition 7, 6.5 and 7 mm respectively). Aqueous extracts show activity against E. coli (MIC 5 mg) and P. aeruginosa (MIC 1 mg) while methanol extracts are active against P. aeruginosa and L. monocytogenes. G. latifolium has potential food and antibacterial uses. PMID:17542064

Eleyinmi, Afolabi F.

2007-01-01

133

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

134

The chemical composition of intercepted cloudwater in the Sierra Nevada  

NASA Astrophysics Data System (ADS)

The chemical composition of cloudwater in the Sierra Nevada is dominated by NO 3-, SO 42-, and NH 4+. Cloudwater pH is determined largely by the balance between the concentrations of these three species, although inputs of formic and acetic acid also are believed to be important, particularly when anthropogenic inputs are small. Cloudwater samples collected in Sequoia National Park (SNP) exhibited pH values ranging from 3.9 to 6.5; Yosemite National Park (YNP) cloudwater samples had pH values ranging from 3.8 to 5.2. Samples collected at YNP were more acidic than those collected at SNP. The difference in pH between the two regions appears to be due to relatively small differences in inputs of NO 3-, SO 42-, and NH 4+. In the absence of inputs of NH 3, cloudwater pH values in the Sierra may fall below 3. Over 250 h of cloud interception were observed during a 12 month period at a cloud monitoring site at 1856 m elevaton in SNP. Estimates of cloudwater deposition of NO 3-, SO 42-, and NH 4+ indicate that cloud interception contributes significantly to regional acid deposition for closed forest canopies. Cloud interception may be the dominant deposition mechanism for isolated conifers and ridgetop canopies, where wind speeds are higher and cloudy air parcels can impact directly on foliar surfaces.

Collett, Jeffrey L.; Daube, Bruce C.; Hoffmann, Michael R.

135

Chemical Compositions of Four Metal-poor Giants  

E-print Network

We present the chemical compositions of four K giants CS 22877-1, CS 22166-16, CS22169-35 and BS 16085 - 0050 that have [Fe/H] in the range -2.4 to -3.1. Metal-poor stars with [Fe/H] < -2.5 are known to exhibit considerable star - to - star variations of many elements. This quartet confirms this conclusion. CS 22877-1 and CS 22166-16 are carbon-rich. There is significant spread for [$\\alpha$/Fe] within our sample where [$\\alpha$/Fe] is computed from the mean of the [Mg/Fe], and [Ca/Fe] ratios. BS 16085 - 0050 is remarkably $\\alpha$ enriched with a mean [$\\alpha$/Fe] of $+$0.7 but CS 22169-35 is $\\alpha$-poor. The aluminium abundance also shows a significant variation over the sample. A parallel and unsuccessful search among high-velocity late-type stars for metal-poor stars is described.

Sunetra Giridhar; David L. Lambert; Guillermo Gonzalez; Gajendra Pandey

2001-02-18

136

Chemical vapor infiltration of TiB{sub 2} composites  

SciTech Connect

Efficiency of the Hall-Heroult electrolytic reduction of aluminum can be substantially improved by the use of a TiB{sub 2} cathode surface. The use of TiB{sub 2}, however, has been hampered by the brittle nature of the material and the grain-boundary attack of sintering-aid phases by molten aluminum. In the current work, TiB{sub 2} is toughened through the use of reinforcing fibers, with chemical vapor infiltration (CVI) used to produce pure TiB{sub 2}. It has been observed, however, that the formation of TiB{sub 2} from chloride precursors at fabrication temperatures below 900 to 1000{degrees}C alloys the retention of destructive levels of chlorine in the material. At higher fabrication temperatures and under appropriate infiltration conditions, as determined from the use of a process model, a TIB{sub 2}THORNEL P-25 fiber composite, 45 mm in diam and 6 mm thick, has been fabricated in 20 h. The material has been demonstrated to be stable in molten aluminum in short-duration tests.

Besmann, T.M.; Miller, J.H.; Cooley, K.C.; Lowden, R.A. [Oak Ridge National Lab., TN (United States); Starr, T.L. [Georgia Tech Research Inst., Atlanta, GA (United States)

1993-01-01

137

Chemical vapor infiltration of TiB[sub 2] composites  

SciTech Connect

Efficiency of the Hall-Heroult electrolytic reduction of aluminum can be substantially improved by the use of a TiB[sub 2] cathode surface. The use of TiB[sub 2], however, has been hampered by the brittle nature of the material and the grain-boundary attack of sintering-aid phases by molten aluminum. In the current work, TiB[sub 2] is toughened through the use of reinforcing fibers, with chemical vapor infiltration (CVI) used to produce pure TiB[sub 2]. It has been observed, however, that the formation of TiB[sub 2] from chloride precursors at fabrication temperatures below 900 to 1000[degrees]C alloys the retention of destructive levels of chlorine in the material. At higher fabrication temperatures and under appropriate infiltration conditions, as determined from the use of a process model, a TIB[sub 2]THORNEL P-25 fiber composite, 45 mm in diam and 6 mm thick, has been fabricated in 20 h. The material has been demonstrated to be stable in molten aluminum in short-duration tests.

Besmann, T.M.; Miller, J.H.; Cooley, K.C.; Lowden, R.A. (Oak Ridge National Lab., TN (United States)); Starr, T.L. (Georgia Tech Research Inst., Atlanta, GA (United States))

1993-01-01

138

Characterization of Indian beers: chemical composition and antioxidant potential.  

PubMed

Chemical composition, antioxidant potential and corresponding lipid preoxidation of Indian commercial beers were evaluated. The presence of polyphenolic compounds such as tannic acid, gallic acid, catechol, vanillin, caffeic acid, quercetin, p-coumaric acid and rutin was quantified using LC-MS while the organic acids including tartaric, malic, acetic, citric and succinic acids were analysed using HPLC. Beer sample B8 had the greatest concentration of phenolic and flavonoid components (0.620?±?0.084 mg/mL and 0.379?±?0.020 mg/mL respectively) among the beer samples studied. The DPPH radical scavenging activity was observed in the range of 68.34?±?0.85 % to 89.90?±?0.71 % and ABTS radical cation scavenging activity was in the range of 59.75?±?0.20 % to 76.22?±?0.50 %. Percent protection in lipid peroxidation was quantified to be maximum (54.45?±?3.39 %) in sample B5. Total phenolic content positively correlates with antioxidant assays, DPPH and ABTS (r?=?0.35 and r?=?0.58 respectively) with p?

Pai, Tapasya V; Sawant, Siddhi Y; Ghatak, Arindam A; Chaturvedi, Palak A; Gupte, Arpita M; Desai, Neetin S

2015-03-01

139

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

140

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

141

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.

Anthony Carpi

2003-03-27

142

Physiological change in camel milk composition ( Camelus dromedarius ) 2: physico-chemical composition of colostrum  

Microsoft Academic Search

Eleven samples of dromedary camel colostrum in Kazakhstan, which originated from one farm only, were collected to study the\\u000a changes in the physico-chemical composition (total fat, total protein, iodine index, lactose, calcium, phosphorus, iron, vitamin\\u000a C, urea, ammonia, density, Dornic acidity, pH, and skimmed dry matter) all along the first postpartum week. At that time,\\u000a the fat matter decreased from

G. Konuspayeva; B. Faye; G. Loiseau; M. Narmuratova; A. Ivashchenko; A. Meldebekova; S. Davletov

2010-01-01

143

Lunar clinopyroxenes: Chemical composition, structural state, and texture  

USGS Publications Warehouse

Single-crystal x-ray diffraction, microprobe, optical and electron optical examinations of clinopyroxenes from Apollo 11 lunar samples 10003, 10047, 10050, and 10084 show that generally the crystals are composed of (001) augite-pigeonite intergrowths in varying ratios. Transmission electron micrographs reveal abundant exsolution lamellae, many only 60 A?? thick. In addition to the phase inhomogeneities, primary chemical inhomogeneities are clearly demonstrated. There are reciprocal relationships between calcium and iron and between Ti4+ + 2Al and R2+ + 2Si. Our evidence suggests that a chemically inhomogeneous subcalcic C2/c augite was the only primary pyroxene from which pigeonite later exsolved.

Ross, M.; Bence, A.E.; Dwornik, E.J.; Clark, J.R.; Papike, J.J.

1970-01-01

144

Origin and Bulk Chemical Compositions of the Inner Planets  

NASA Astrophysics Data System (ADS)

The well-defined orbital gradation of the uncompressed mean densities /line?unc of the terrestrial planets attest to the existence of similar heliocentric gradations of temperature and pressure in the nebular gas from which these bodies condensed (Lewis, Science 186 440-443 1974). This trend of /line?unc, coupled with the very different chemical signatures of each planet, such as the almost zero state of Fe oxidisation in Mercury, the dryness of Venus' atmosphere, and the likely existence of liquid FeS in the Earth's core, suggest that each planet condensed within a narrow feeding zone, close to its present orbit. These features are explained by the modern Laplacian theory [MLT] of solar system origin (Earth, Moon & Planets 87 11-55 2001; Abstract # 8061 in Mercury 2001 Workshop - see URL below). According to the MLT, the planetary system condensed from a concentric family of orbiting gas rings which were shed by the contracting proto-solar cloud [PSC]. Discrete ring shedding occurs if there exists a steep density inversion at the cloud's photosurface, with the gas density ? rising ~ 35-fold. Previously it has been suggested that such an inversion comes about solely through the action of a large turbulent stress pt arising from supersonic convective motions within a uniformly superadiabatic interior (BAAS 23 1232 1991; Eos Trans. AGU 76 F332 1995). For a non-rotating cloud pt = ? ? GM(r)/r, where M(r) is the mass inside radius r and ? ~ 0.1 is a constant. This requires pt rising to ~ 35pgas, which seems unlikely. Here pgas = ? ? T/? , T is temperature and ? is molecular weight. I now report a new PSC model which incorporates the findings of a numerical simulation of supersonic thermal convection in a model atmospheric layer (BAAS 32 1102 2000). The new model has an adiabatic core of radius r1 in which ? = ? 1, a constant. This core is surrounded by a superadiabatic envelope of polytropic index n = -1 in which ? falls to 0 at the surface [s] according as ? = ? 1(? - ? s})/(? {1 - ? s). Here ? = ? cT(r)/? Tc, c means the centre, ? 1 = ? c}T(r{1})/?_{1 Tc, etc. If the controlling parameters ? 1, ? s, ? 1 stay constant, then the contracting cloud sheds gas rings whose mean orbital radii Rn (n=0,1,2, ...) form a closely geometric sequence. The choice ? = 0.1253, ? s = 0.00232 and ? 1 = 7.6 ? s leads to the detachment of a family of gas rings whose evolved radii Rn match the observed mean planetary spacings and whose condensate bulk chemical compositions yield densities in accord with the values /line?unc. The maximum value of pt}/p{gas in the PSC, occurring at radius r = r1, is now only 11.3. The initial mass of the PSC is 1.197M? . The loss of cloud mass during contraction to present solar size results in the orbital expansion of all gas rings and condensate material after ring detachment. Earth's gas ring was shed at 0.917 AU. Details of the gas ring temperatures, mean orbit pressures and condensate compositions are given in the URL below. Notably, Mercury formed at 1632 K and consists mostly of Fe-Ni-Cr-Co-V alloy (mass fraction: 0.670) and gehlenite (0.254). For Venus (911 K), the condensate contains metal alloy (0.326) and MgO-SiO2 (0.575). (Fe-Ni)S (0.087) and tremolite (0.102) first condense at Earth's orbit (674 K). FeO, as fayalite (0.180), first forms at Mars' (459 K). I thank Mr. David Warren [Tasmania], Dr. John D. Anderson [NASA/JPL] and the ARC for support.

Prentice, A. J.

2001-12-01

145

Giant squid skin gelatin: Chemical composition and biophysical characterization  

Microsoft Academic Search

Gelatin was extracted from the skin of giant squid (Dosidicus gigas) with a yield of 7.5% on a wet weight basis through a novel cold maturation process and it was chemical, physicochemical and structurally characterized. Squid skin gelatin (SSG) had high protein content (89%) with an amino acid profile similar to that of interstitial collagen. Infrared spectroscopy and circular dichroism

Mario H. Uriarte-Montoya; Hisila Santacruz-Ortega; Francisco J. Cinco-Moroyoqui; Ofelia Rouzaud-Sández; Maribel Plascencia-Jatomea; Josafat M. Ezquerra-Brauer

2011-01-01

146

Chemical composition of Monsoon deposition in the Everest region  

Microsoft Academic Search

Between 1990 and 1994 a campaign for sampling summer depositions was carried out in the Everest region (Khumbu Valley, Nepal) in order to understand the physical, chemical and transport processes responsible for the ion chemistry in the deposition of this region. Wet and bulk depositions at 5050 m a.s.l. and snow samples from 5515 to 7400 m altitude were collected.

S Valsecchi; C Smiraglia; G Tartari; S Polesello

1999-01-01

147

Chemical composition of pen surface layers of beef cattle feedyards  

Technology Transfer Automated Retrieval System (TEKTRAN)

The biological, physical, and chemical characteristics of beef cattle feedyard pen surfaces may affect nutrient transformations and losses to the atmosphere, ground water, or surface water. Feedyard pen surfaces can typically segregate into three or four layers. The purpose of this study was to dete...

148

Floral Scent in Wisteria: Chemical Composition, Emission Pattern and Regulation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Volatile chemicals emitted from the flowers of Chinese wisteria (Wisteria sinenesis) and Japanese wisteria (W. floribunda) were collected using a dynamic headspace technique and identified by a gas chromatography-mass spectrometry. About 30 and 22 compounds were detected from Chinese wisteria and Ja...

149

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

150

A study on chemical composition and detection of chemical adulteration in tetra pack milk samples commercially available in Multan.  

PubMed

The aim of this study was to analyze and compare the chemical composition of 8 tetra pack milk samples, Olpers (S1), Haleeb (S2), Good milk (S3), Everyday (S4), Milk Pack (S5), Dairy Queen (S6), Dairy Umang (S7), Nurpur (S8) available in local markets and to detect the presence of various chemical adulterants in tetra pack milk samples in Southern Punjab (Pakistan). Density, pH, solid not fat, total solids, lactometer reading, specific gravity and fat contents were analyzed to determine the chemical composition of milk samples. Our results revealed that all the studied parameters had statistically non significant differences (P>0.05) except total fat in milk samples which was significantly different (P=0.03) among the 8 studied milk samples. Presence of a number of chemical adulterants, formalin, cane sugar, starch, glucose, ammonium sulphate, salt, pulverized soap, detergents, skim milk powder, benzoic acid, salicylic acid, borax, boric acid and alkalinity were also detected in milk samples following standard procedures. Results indicated that formalin, cane sugar, glucose, alkalinity and benzoic acid were present in all samples while salt test was positive only for Olper milk. All other studied adulterants were not detected in 8 milk samples under study. % fat was the only significantly different feature among the studied milk quality parameters with S8 containing lowest while S5 having the maximum % fat. PMID:24374447

Awan, Adeela; Naseer, Misbah; Iqbal, Aasfa; Ali, Muhammad; Iqbal, Rehana; Iqbal, Furhan

2014-01-01

151

Growth of multi-component alloy films with controlled graded chemical composition on sub-nanometer scale  

DOEpatents

The chemical composition of thin films is modulated during their growth. A computer code has been developed to design specific processes for producing a desired chemical composition for various deposition geometries. Good agreement between theoretical and experimental results was achieved.

Bajt, Sasa; Vernon, Stephen P.

2005-03-15

152

On the chemical composition of L-chondrites  

NASA Technical Reports Server (NTRS)

Radiochemical neutron activation analysis of Ag, As, Au, Bi, Co, Cs, Ga, In, Rb, Sb, Te, Tl, and Zn and major element data in 14 L4-6 and 3 LL5 chondrites indicates that the L group is unusually variable and may represent at least 2 subgroups differing in formation history. Chemical trends in the S/Fe rich subgroup support textural evidence indicating late loss of a shock formed Fe-Ni-S melt; the S/Fe poor subgroup seemingly reflects nebular fractionation only. Highly mobile In and Zn apparently reflect shock induced loss from L chondrites. However, contrasting chemical trends in several L chondrite sample sets indicate that these meteorites constitute a more irregular sampling of, or more heterogeneous parent material than do carbonaceous or enstatite chondrites. Data for 15 chondrites suggest higher formation temperatures and/or degrees of shock than for LL5 chondrites.

Neal, C. W.; Dodd, R. T.; Jarosewich, E.; Lipschutz, M. E.

1980-01-01

153

Effect of weather damage on the chemical composition of soybeans  

Microsoft Academic Search

Summary  Soybean samples containing a large proportion of damaged seed were separated into sound and damaged portions and these portions\\u000a were then analyzed chemically.\\u000a \\u000a Analysis of these samples indicated that damage to the seed caused considerable variation in percentages of oil, protein,\\u000a ash, and in iodine number and acid of the oil. Sugars in the damaged portions of the soybean samples

Orland A. Krober; F. I. Collins

1948-01-01

154

Chemical vapor infiltration: Dispersed and graded depositions for ceramic composites  

Microsoft Academic Search

A structured-geometry model for dispersed and graded deposits was developed for chemical vapor infiltration of multiply-woven substrates of carbon filters. An earlier model was modified to allow for two reactants in the feed. The model predicts gas-phase concentration profiles in the voids of substrates and deposition amounts of two reactants as a function of time and location. Results are shown

G. Y. Chung; B. J. McCoy; J. M. Smith; Domenick E. Cagliostro

1993-01-01

155

Regulating continent growth and composition by chemical weathering  

PubMed Central

Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are possible solutions, but the relative magnitudes of each process have never been quantitatively constrained because of the lack of appropriate data. Here, we show that the relative contributions of these processes can be obtained by simultaneous examination of Mg and Li (an analog for Mg) on the regional and global scales in arcs, delaminated lower crust, and river waters. At least 20% of Mg is lost from continents by weathering, which translates into >20% of continental mass lost by weathering (40% by delamination). Chemical weathering leaves behind a more Si-rich and Mg-poor crust, which is less dense and hence decreases the probability of crustal recycling by subduction. Net continental growth is thus modulated by chemical weathering and likely influenced by secular changes in weathering mechanisms. PMID:18362343

Lee, Cin-Ty Aeolus; Morton, Douglas M.; Little, Mark G.; Kistler, Ronald; Horodyskyj, Ulyana N.; Leeman, William P.; Agranier, Arnaud

2008-01-01

156

Regulating continent growth and composition by chemical weathering  

USGS Publications Warehouse

Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are possible solutions, but the relative magnitudes of each process have never been quantitatively constrained because of the lack of appropriate data. Here, we show that the relative contributions of these processes can be obtained by simultaneous examination of Mg and Li (an analog for Mg) on the regional and global scales in arcs, delaminated lower crust, and river waters. At least 20% of Mg is lost from continents by weathering, which translates into >20% of continental mass lost by weathering (40% by delamination). Chemical weathering leaves behind a more Si-rich and Mg-poor crust, which is less dense and hence decreases the probability of crustal recycling by subduction. Net continental growth is thus modulated by chemical weathering and likely influenced by secular changes in weathering mechanisms. ?? 2008 by The National Academy of Sciences of the USA.

Lee, C.-T.A.; Morton, D.M.; Little, M.G.; Kistler, R.; Horodyskyj, U.N.; Leeman, W.P.; Agranier, A.

2008-01-01

157

The chemical composition of subducting sediment and its consequences for the crust and mantle  

Microsoft Academic Search

Subducted sediments play an important role in arc magmatism and crust–mantle recycling. Models of continental growth, continental composition, convergent margin magmatism and mantle heterogeneity all require a better understanding of the mass and chemical fluxes associated with subducting sediments. We have evaluated subducting sediments on a global basis in order to better define their chemical systematics and to determine both

Terry Plank; Charles H. Langmuir

1998-01-01

158

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

159

Rapid computation of chemical equilibrium composition - An application to hydrocarbon combustion  

NASA Technical Reports Server (NTRS)

A scheme for rapidly computing the chemical equilibrium composition of hydrocarbon combustion products is derived. A set of ten governing equations is reduced to a single equation that is solved by the Newton iteration method. Computation speeds are approximately 80 times faster than the often used free-energy minimization method. The general approach also has application to many other chemical systems.

Erickson, W. D.; Prabhu, R. K.

1986-01-01

160

Chemical composition and emission sources of South Asian fine particulate matter estimated from satellite observations and a chemical transport model  

NASA Astrophysics Data System (ADS)

Epidemiologic and health impact studies are inhibited by the paucity of long-term measurements of the chemical composition of fine particulate matter, especially over the rapidly developing South Asian region. We applied a novel approach of collecting information from satellite observations and chemical transport model simulations to estimate the chemical composition and emission sources of long-term average ground-level PM2.5. We developed speciated PM2.5 concentrations and emission sources at a spatial resolution of approximately 10x10 km2 for 2004-2008 from aerosol optical depth measured from satellite instruments (MODIS and MISR), and coincident aerosol vertical profile and composition information from a global chemical transport model (GEOS-Chem). Evaluation of the dataset with North American in situ measurements indicated a significant spatial agreement. In situ measurements agreed better with the satellite-based product than the GEOS-Chem simulation. We found that South Asian population-weighted concentrations are dominated by secondary inorganic species (14.3 ug/m3), mineral dust (7.8 ug/m3), and particulate organic matter (7.4 ug/m3) components. Secondary inorganic aerosol concentrations exceeded 30 ug/m3 over the Indo-Gangetic Plain. The population-weighted mean uncertainty (1 SD) is 2.9 ug/m3 for secondary inorganic, 4.7 ug/m3 for mineral dust, and 3.0 ug/m3 for particulate organic matter, as estimated from uncertainty in aerosol optical depth, accuracy of the simulated aerosol vertical profile and speciation, and sampling.

Philip, S.; Martin, R. V.; van Donkelaar, A.; Wang, Y.; CHEN, D.; Zhang, L.

2012-12-01

161

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

162

Influence of chemical surface modification on the properties of biodegradable jute fabrics—polyester amide composites  

Microsoft Academic Search

The chemical surface modifications of jute fabrics involving bleaching, dewaxing, alkali treatment, cyanoethylation and vinyl grafting are made in view of their use as reinforcing agents in composites based on a biodegradable polyester amide matrix, BAK 1095. The effect of different fibre surface treatments and fabric amounts on the performance of resulting composites are investigated. The mechanical properties of composites

A. K Mohanty; M. A Khan; G Hinrichsen

2000-01-01

163

Chemical composition of Earth's primitive mantle and its 1. Method and results  

E-print Network

Chemical composition of Earth's primitive mantle and its variance: 1. Method and results Tanya composition of Earth's primitive mantle along with its variance. Earth's primitive mantle is located, and this depleted nature is further amplified (up to 60%) in terms of predicted composition for the present-day

Mcdonough, William F.

164

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...

165

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...

166

Introduced forage species herbage dry matter production and chemical composition at two  

E-print Network

Introduced forage species herbage dry matter production and chemical composition at two moist of introduced forage species whose seed were provided by ILCA's gene bank were evaluated for adaptation and dry

Paris-Sud XI, Université de

167

Concentration and chemical composition of PM 2.5 in Shanghai for a 1-year period  

Microsoft Academic Search

Weekly PM2.5 samples were collected in Shanghai, China at two sites, Tongji University and Hainan Road. Sampling started in March 1999 and was conducted for 1 year. The ambient mass concentration and chemical composition of the PM2.5 were determined. Chemical analyses included elemental composition, water-soluble ions, and organic and elemental carbon. Weekly PM2.5 mass concentrations ranged from 21 to 147?g\\/m3,

Boming Ye; Xueli Ji; Haizhen Yang; Xiaohong Yao; Chak K. Chan; Steven H. Cadle; Tai Chan; Patricia A. Mulawa

2003-01-01

168

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

169

[Analysis of main chemical composition in hydrogenated rosin from Zhuzhou].  

PubMed

The acid fraction, the main part of the hydrogenated rosin produced by Zhuzhou Forest Chemicals Plant of China, was separated from neutral fraction by modified DEAE-Sephadex ion exchange chromatography and analyzed with GC-MS-DS technique by using DB-5 capillary column. Six dihydroabietic-type resin acids, four dihydropimaric/isopimaric-type resin acids and four tetrahydroabietic-type resin acids were identified. The hydrogenated rosin is composed mainly of 8-abietenoic acid, 18-abietanoic acid, 13-abietenoic acid, 8 alpha, 13 beta-abietanoic acid, 13 beta-8-abietenoic acid and 8-isopimarenoic acid etc. PMID:12541853

Duan, W G; Chen, X P; Wang, L L; Deng, S; Zhou, Y H; An, X N

2001-01-01

170

Variations in chemical composition of Apollo 15 mare basalts  

NASA Technical Reports Server (NTRS)

Chemical analyses of 30 different Apollo 15 mare basalts were examined to evaluate the effects of closure on the pearson moment correlation coefficient. It is shown possible to describe the Apollo 15 mare basalts in terms of an opaque, an olivine/pyroxene, an anorthite, and a KREEP component, if significant correlations are identified using the expected correlations as null values. Using Q-mode cluster analysis and nonlinear mapping, it is possible to recognize three groups of the mare basalts, groups 1 and 2 belonging to the olivine normative basalt cluster and group 3 to the quartz normative cluster.

Butler, J. C.

1976-01-01

171

A rapid method for the computation of equilibrium chemical composition of air to 15000 K  

NASA Technical Reports Server (NTRS)

A rapid computational method has been developed to determine the chemical composition of equilibrium air to 15000 K. Eleven chemically reacting species, i.e., O2, N2, O, NO, N, NO+, e-, N+, O+, Ar, and Ar+ are included. The method involves combining algebraically seven nonlinear equilibrium equations and four linear elemental mass balance and charge neutrality equations. Computational speeds for determining the equilibrium chemical composition are significantly faster than the often used free energy minimization procedure. Data are also included from which the thermodynamic properties of air can be computed. A listing of the computer program together with a set of sample results are included.

Prabhu, Ramadas K.; Erickson, Wayne D.

1988-01-01

172

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

173

Chemical composition of water from roofs in Gdansk, Poland.  

PubMed

This study deals with the assessment of roof runoff waters from the region of Gdansk collected during the winter season (2007/2008). The chemical analysis includes 16 chemical variables: major ions, PAHs and PCBs measured at 3 sampling sites for 6-14 rain events. Although the data set is of limited volume the statistical data treatment using self-organizing maps (SOM) reveals the main factors controlling roof runoff water quality even for a data set with small dimension. This effort for explanation of the identified factors by the possible emission sources of the urban environment and air-particulate formation seems to be very reliable. Additionally to the roof runoff water quality factors the rain events patterns are found: "background" group of events and groups formally named "PAHs", "PCBs" and "air-borne particles"--dominated events. The SOM classification results give an opportunity to uncover the role of roof "impact" on the runoff waters. Rain runoff water quality is described by four latent factors and the "roof" impact is uncovered. PMID:19695751

Tsakovski, Stefan; Tobiszewski, Marek; Simeonov, Vasil; Polkowska, Zaneta; Namie?nik, Jacek

2010-01-01

174

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

175

Chemical Oxidation  

Microsoft Academic Search

Chemical oxidation is a process involving the transfer of electrons from an oxidizing reagent to the chemical species being\\u000a oxidized. In water and wastewater engineering, chemical oxidation serves the purpose of converting putrescible pollutant substances\\u000a to innocuous or stabilized products. Chemical oxidation processes take place in natural waters and serve as an important mechanism\\u000a in the natural self-purification of surface

Nazih K. Shammas; John Y. Yang; Pao-Chiang Yuan; Yung-Tse Hung

176

Home Chemicals  

NSDL National Science Digital Library

This lesson provides an introduction to the occurrence and possible risks of household chemical products. Topics include some basic chemistry (how elements combine to form compounds), how chemicals are classified, and the idea of natural, as opposed to synthetic, chemicals. The lesson includes an activity in which students take an inventory of chemical products in their homes and research the possible hazards of some of them using an online resource developed by the National Institutes of Health (NIH).

Chris Fox

177

[Spectroscopic studies on different chemical composition between the shell and core of Radix Notoginseng].  

PubMed

Notoginseng (Sanqi) is one of the most important components of famous Chinese recipe (Yunan Baiyao) and possesses a wide variety of applications in clinical practice. It has been found that Sanqi of different size exhibits different curative effects. Such a phenomenon may be attributed to that the chemical constituent from shell region is different from that of core region. To prove the above-mentioned hypothesis, Ultraviolet-Visible (UV-Vis), FTIR, fluorescence spectroscopy, together with high performance liquid chromatography (HPLC) and electrospray ionization mass spectroscopy (ESI-MS) were utilized to study the variation of chemical compositions from shell and core regions of Sanqi. The results demonstrate that the chemical compositions of Sanqi from shell and core regions are different. In summary, differences in chemical composition between Sanqi shell and core were manifested from versatile aspects. Such differences shed a light on the different curative effects of Sanqi. PMID:16097691

Liu, Zhi; Li, Sai-jun; Tian, Hong-bo; Xu, Yi-zhuang; Wu, Jin-guang

2005-04-01

178

Relationship between chemical composition and in situ rumen degradation characteristics of maize silages in dairy cows.  

PubMed

Several in situ studies have been conducted on maize silages to determine the effect of individual factors such as maturity stage, chop length and ensiling of maize crop on the rumen degradation but the information on the relationship between chemical composition and in situ rumen degradation characteristics remains scarce. The objectives of this study were to determine and describe relationships between the chemical composition and the rumen degradation characteristics of dry matter (DM), organic matter (OM), CP, starch and aNDFom (NDF assayed with a heat stable amylase and expressed exclusive of residual ash) of maize silages. In all, 75 maize silage samples were selected, with a broad range in chemical composition and quality parameters. The samples were incubated in the rumen for 2, 4, 8, 16, 32, 72 and 336 h, using the nylon bag technique. Large range was found in the rumen degradable fractions of DM, OM, CP, starch and aNDFom because of the broad range in chemical composition and quality parameters. The new database with in situ rumen degradation characteristics of DM, OM, CP, starch and aNDFom of the maize silages was obtained under uniform experimental conditions; same cows, same incubation protocol and same chemical analysis procedures. Regression equations were developed with significant predictors (P<0.05) describing moderate and weak relationships between the chemical composition and the washout fraction, rumen undegradable fraction, potentially rumen degradable fraction, fractional degradation rate and effective rumen degradable fraction of DM, OM, CP, starch and aNDFom. PMID:25023203

Ali, M; van Duinkerken, G; Cone, J W; Klop, A; Blok, M C; Spek, J W; Bruinenberg, M H; Hendriks, W H

2014-11-01

179

Chemical Innovation  

NSDL National Science Digital Library

Free online through December 2000, Chemical Innovation is a monthly journal that explores topics in research and development in chemical industries, and features such departments as Patent Watch, Chemist at Large, Book Alert, and The Industrial Chemist. The journal also shows a lighter side by including chemistry-related cartoons and jokes. The online version is provided by the American Chemical Society.

180

Surface submicron aerosol chemical composition: What fraction is not sulfate?  

NASA Astrophysics Data System (ADS)

Measurements of submicron aerosol mass and the mass of major ionic components have been made over the past 5 years on cruises in the Pacific and Southern Oceans and at monitoring stations across North America (Barrow, Alaska; Cheeka Peak, Washington; Bondville, Illinois; and Sable Island, Nova Scotia). Reported here are submicron concentrations of aerosol mass, nonsea salt (nss) sulfate, sea salt, methanesulfonate, other nss inorganic ions, and residual, or chemically unanalyzed, mass. Residual mass concentrations are based on the difference between simultaneously measured aerosol mass and the mass of the major ionic components. A standardized sampling protocol was used for all measurements making the data from each location directly comparable. For the Pacific and Southern Oceans, concentrations of the chemical components are presented in zonally averaged 20° latitude bins. For the monitoring stations, mean concentrations are presented for distinct air mass types (marine, clean continental, and polluted based on air mass back trajectories). In addition, percentile information for each chemical component is given to indicate the variability in the measured concentrations. Mean nss sulfate submicron aerosol mass fractions for the different latitude bins of the Pacific ranged from 0.14±0.01 to 0.34±0.03 (arithmetic mean±absolute uncertainty at the 95% confidence level). The lowest average value occurred in the 40°-60°S latitude band where nss sulfate concentrations were low due to the remoteness from continental sources and sea salt concentrations were relatively high. Mean nss sulfate aerosol mass fractions were more variable at the monitoring stations ranging from 0.13±0.004 to 0.65±0.02. Highest values occurred in polluted air masses at Bondville and Sable Island. Sea salt mean mass fractions ranged between 0.20±0.02 and 0.53±0.03 at all latitude bands of the Pacific (except 20°-40°N where the residual mass fraction was relatively high) and at Barrow. The concentration of residual mass was significant at the 95% confidence level at all stations and all Pacific latitude bands (assuming that all errors were random and normally distributed and contamination of the samples did not occur beyond that accounted for by storage and transport uncertainties). Mean residual mass fractions ranged from 0.09±0.07 to 0.74±0.04.

Quinn, P. K.; Bates, T. S.; Miller, T. L.; Coffman, D. J.; Johnson, J. E.; Harris, J. M.; Ogren, J. A.; Forbes, G.; Anderson, T. L.; Covert, D. S.; Rood, M. J.

2000-03-01

181

Antiinflammatory activity and chemical composition of extracts of Verbena officinalis.  

PubMed

In an attempt to locate the biologically active fraction(s) of the plant Verbena officinalis Linn. (Verbenaceae), a preliminary screening of successive petroleum ether, chloroform and methanol extracts of aerial parts for antiinflammatory activity using carrageenan paw oedema model was carried out. All three extracts were found to exhibit antiinflammatory activity with the chloroform extract being the most active. Chemical investigations of petroleum ether and chloroform extracts led to the isolation of beta-sitosterol, ursolic acid, oleanolic acid, 3-epiursolic acid, 3-epioleanolic acid, and minor triterpenoids of derivatives of ursolic acid and oleanolic acids. Chromatographic purification of the methanol extract yielded two iridoid glucosides, verbenalin and hastatoside, a phenylpropanoid glycoside, verbascoside and beta-sitosterol-D-glucoside. PMID:10960904

Deepak, M; Handa, S S

2000-09-01

182

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

183

Composition changes in bombarded oxides and carbides: the distinction between ballistic, chemically guided, and chemically random behavior  

NASA Astrophysics Data System (ADS)

When oxides or carbides are bombarded it is commonly observed that new phases or compositions appear. Like ion beam mixing, the changes fall into categories which we term ballistic, chemically guided motion of defects, and chemically random motion of defects. An example of a ballistic change is a near-threshold process, as when O is lost from Ta 2O 5 or C is lost from TaC due to 1 keV He + impact. Chemically guided defects are inferred when the changes correlate with thermodynamics (i.e. with the enthalpy increase), volatility, Gibbsian segregation, or defect-induced transport. For example, O loss from transition metal oxides is conventionally taken as chemically guided by virtue of correlating with thermodynamics. Likewise, C loss from SiC in some cases correlates with the C being transported to the surface and then being subject to sputtering. Chemically random processes, in which thermodynamics, etc. are not relevant, are believed to occur when oxides are bombarded with N + or N 2+. A typical example is found with TiO 2, where O 2+ impact leads to TiO 2.00 and Ar + impact to TiO 1.66, the latter being equivalent to the Ti 2O 3 seen by electron diffraction. Finally, N 2+ impact leads to TiO 1.12N 0.60, and since the sum O+ N is similar to O alone after Ar + impact we infer a random replacement of O by N. A similar pattern is shown by B 2C 3, Al 2O 3, SiO 2, GeO 2, ZrO 2, V 2O 5, and Nb 2O 5. A somewhat different response is shown by SiC. Here N + impact leads to a replacement of C by N but the sum C + N significantly exceeds the initial C content. Evidently the replacement is not stoichiometric but it still constitutes a clear example of chemically random behavior.

Kelly, Roger; Bertóti, Imre; Miotello, Antonio

1993-06-01

184

The chemical composition of cork and phloem in the rhytidome of Quercus cerris bark  

Microsoft Academic Search

Quercus cerris is an important oak species in Eastern Europe and Minor Asia that has a thick bark with a substantial content of cork tissues in its rhytidome. The chemical composition of the cork and of the interspersed phloemic tissues in the rhytidome of Q. cerris var. cerris from mature trees from Turkey was investigated in relation to summative composition,

Ali ?en; Isabel Miranda; Sara Santos; José Graça; Helena Pereira

2010-01-01

185

Use of chemical fibre processing wastes for fabrication of thermoplastic composites  

Microsoft Academic Search

The behavior of the components of an inseparable mixture of processing wastes containing polyamide, polyacrylonitrile, and cellulose fibres was investigated. The possibility of using them in production of wood—polymer composites if cyclization in the structure of PAN and chemical reaction of basic and acid functional groups play the determining role in intensification of the interfacial interaction in the composite and

T. V. Nemilova; E. P. Romanova; T. V. Zosina; G. I. Tsarev

1996-01-01

186

[Review on chemical composition and constituents of some important exotic fruits (author's transl)].  

PubMed

In this paper the chemical composition and the known constituents of mango, pomegranate, passion fruits, papaya, guava, feijoa, litchi, cherimoya and other Annona-species, japanese persimmone, acerola, prickly pears, naranjilla, tamarillo and cape-gooseberry are reviewed. The composition of avocado and kiwi is shortly refered. PMID:7023094

Herrmann, K

1981-01-01

187

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

188

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

189

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

190

Application of chemical vapor composites (CVC) to terrestrial thermionics  

NASA Astrophysics Data System (ADS)

Terrestrial flame fired thermionics took a great leap forward in the earlier 1980's with the development of reliable long-lived hot shells. These results were presented by Goodale (1981). The hot shell protects the fractory emitter from oxidizing in the combustion environment. In earlier efforts with supralloys emitters it was found that superalloys were poor thermionic emitters since they operated at too low a temperature for practical and economical use as discussed by Huffman (1978). With the development of Chemical Vapor Deposited (CVD) silicon carbide and CVD tungsten, it became possible to fabricate long-lived thermionic converters. These results were shown by Goodale (1980). Further improvements were achieved with the use of oxygen additives on the electrodes. These developments made thermionics attractive for topping a power plant or as the energy conversion part of a cogeneration plant as described by Miskolczy (1982) and Goodale (1983). The feasibility of a thermonic steam boiler and a thermionic topped gas turbine plant become a possibility, as shown by Miskolczy (1980).

Miskolczy, Gabor; Reagan, Peter

1995-01-01

191

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

192

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

193

CHEMICAL COMPOSITION OF SHALE OIL I. DEPENDENCE ON OIL SHALE ORIGIN  

Microsoft Academic Search

Shale oils obtained by nitrogen retorting of North Carolina, Cleveland, Ohio, Colorado, Rundle, Stuart, and Condor oil shales 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

Mark E. Polasky; Sunil Kesavan; Sunggyu Lee

1991-01-01

194

[Chemical weapons and chemical terrorism].  

PubMed

Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary. PMID:16296384

Nakamura, Katsumi

2005-10-01

195

High toughness, 3D textile, SiC\\/SiC composites by chemical vapor infiltration  

Microsoft Academic Search

Three dimensional, textile, Hi-Nicalon, silicon carbide fiber-reinforced, silicon carbide composites with high toughness and reliability were fabricated by chemical vapor infiltration. The mechanical properties of the composite materials were investigated under bending, shear, and impact loading. The density of the composites was 2.5 g cm?3 after the three dimensional silicon carbide perform has been infiltrated for 30 h. The values

Yongdong Xu; Laifei Cheng; Litong Zhang; Hongfeng Yin; Xiaowei Yin

2001-01-01

196

Silicon carbide whisker reinforced silicon carbide composites by chemical vapor infiltration  

Microsoft Academic Search

Silicon carbide (SiC) whisker reinforced SiC ceramic matrix composites were prepared by chemical vapor infiltration. Microstructure and mechanical properties of the composites were investigated. The fracture toughness of the composites was improved to 5.65–7.21MPam1\\/2, and its flexural strength value was between 196MPa and 305MPa, depending on the relative density. The pullout of rough whisker, crack deflection and whisker bridging are

Yunfeng Hua; Litong Zhang; Laifei Cheng; Jing Wang

2006-01-01

197

X-ray Tomographic Study of Chemical Vapor Infiltration Processing of Ceramic Composites  

Microsoft Academic Search

The fabrication of improved ceramic-matrix composites will require a better understanding of processing variables and how they control the development of the composite microstructure. Noninvasive, high-resolution methods of x-ray tomography have been used to measure the growth of silicon carbide in a woven Nicalon-fiber composite during chemical vapor infiltration. The high spatial resolution allows one to measure the densification within

J. H. Kinney; T. M. Breunig; T. L. Starr; D. Haupt; M. C. Nichols; S. R. Stock; M. D. Butts; R. A. Saroyan

1993-01-01

198

Fine particulate chemical composition and light extinction at Meadview, AZ.  

PubMed

The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr day-night 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 microg/m3 organic material, +/- 0.3 microg/m3 ammonium sulfate, and +/- 0.07 microg/m3 ammonium nitrate. Data were also available on fine particulate crustal material, fine and coarse particulate mass from the Interagency Monitoring of Protected Visual Environments sampling system, and relative humidity (RH), light absorption, particle scattering, and light extinction measurements from Project MOHAVE. An extinction budget was obtained using mass scattering coefficients estimated from particle size distribution data. Literature data were used to estimate the change in the mass scattering coefficients for the measured species as a function of RH and for the absorption of light by elemental carbon. 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. During periods of highest light extinction, contributions from fine particulate organic material, sulfate, and light-absorbing carbon dominated the extinction of light by particles. 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. PMID:17195488

Eatough, Delbert J; Cui, Wenxuan; Hull, Jeffery; Farber, Robert J

2006-12-01

199

Chemical Bonds  

NSDL National Science Digital Library

Electrons are key to forming the two broad categories of chemical bonds: covalent and ionic. Atoms, which have a nucleus surrounded by electrons, are represented in several different ways. In the Chemical Bonds activity, students explore the different kinds of chemical bonds that can form, ranging from non-polar covalent to ionic. In the model depicted above students adjust the electronegativity of two atoms and see the effect it has on electron distribution and bond type.

The Concord Consortium

2011-12-11

200

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

201

Morphology, microstructure and chemical composition of single inhalable particles in Shanghai, China.  

PubMed

The morphology, microstructure, and chemical composition of a variety of particles emitted from coal-fired power plants, steel plants, and vehicle exhausts, which are possible sources of particulate matter (PM) in the atmosphere, were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and compared with particle samples collected from urban atmosphere to identify the best footprint or the suitable indicator relating the existence of studied particles and their possible emitters by the morphology, microstructure, and chemical composition of the particles. The investigation indicated that the particles from these three sources are different in morphology, microstructure, and chemical composition. Sphere aggregates were generally the most abundant components, with silicon and aluminum as major elements. The urban air particulate contained particles similar to those observed in the power plant, steel plant, and vehicle exhaust samples suggesting that all three sources are contributing to the pollution in the city. PMID:25252792

Akram, Waheed; Madhuku, Morgan; Ahmad, Ishaq; Xiaolin, Li; Zhang, Guilin; Yan, Li

2014-12-01

202

Effect of interfacial chemical bonding and surface topography on adhesion in carbon fiber/epoxy composites  

SciTech Connect

A series of PAN-based IM6 carbon fibers having varying amounts of surface treatment were, pretreated with compounds representing the constituents encountered in epoxy composites to pre-react any groups on the fiber surface before composite fabrication in order to determine the effect of chemical bonding on fiber-matrix adhesion. Chemical bonding was quantified using XPS. Chemical bonding between reactive groups in amine cured epoxy matrices and the surface groups present on IN46 carbon fibers as a result of commercial surface treatments has been detected although the absolute amount of chemical bonding is low (1-3%). It was found that reaction with monofunctional epoxy groups having hydrocarbon functionalities blocked the surface from further reaction and reduced the adhesion that could be attained to its lowest value. Prereaction with difunctional amines had little effect on adhesion when compared to normal composite fabrication procedures. Prereaction with difunctional epoxy groups did enhance adhesion levels over the level attained in normal composite fabrication methods. These results showed that chemical bonding between epoxy and the carbon fiber surface could increases the adhesion between fiber and matrix about 25% while between the amino group and the carbon fiber surface about 15%. Quantitative measurements of the fiber surface microtopography were made with scanning tunneling microscopy. An increase in roughness was detected with increasing surface treatment. It was concluded that surface roughness also accounted for a significant increase in fiber-matrix adhesion.

Drzal, L.T.; Sugiura, N.; Hook, D. [Michigan State Univ., East Lansing, MI (United States). Composite Materials and Structures Center; [Mitsubishi Rayon Co., Nagoya (Japan)

1994-12-31

203

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

204

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)

205

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

206

Chemical Linkage  

Microsoft Academic Search

IN the Research Items in NATURE of October 20, certain arguments are advanced in opposition to the views which we expressed in a recent paper published in the Journal of the Chemical Society, and without going into detail we wish to take the opportunity of pointing out that : (1) We cannot call to mind any evidence, chemical or physical,

R. F. Hunter; R. Samuel

1934-01-01

207

CHEMICAL COMPOSITION OF CROP BIOMASS IMPACTS ITS DECOMPOSITION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Understanding the interaction between plant components and their subsequent decomposition provides insights on how plant quality differences may influence carbon (C) sequestration within a given management system. Our hypothesis was that decomposition is a function of biochemical composition when al...

208

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

209

Chemical composition of Mount St. Helens volcanic ash  

Microsoft Academic Search

Volcanic ash samples from the May 18, 1980, Mount St. Helens eruption were analyzed for major, minor, and trace composition by a variety of analytical techniques. Results indicate that the basic composition of the ash consists of approximately 65% SiO2, 18% Al2O3, 5% FetO3, 2% MgO, 4% CaO, 4% Na2O, and 0.1% S. Thirty seven trace metals are reported including

H. E. Taylor; F. E. Lichte

1980-01-01

210

Estimation of Macronutrient Content in Kindergartens Meals: Food Composition Tables or Chemical Analysis?  

PubMed Central

Objective: The nutrition of children in kindergartens has a great significance for proper growth and development of children. In order to save time and money, the control of macronutrients content is performed by calculations using food composition tables instead of performing a chemical analysis. Methods: We examined the macronutrients content of 240 whole day meals using food composition tables and performed chemical analysis of meals to determine adequacy and validity of food composition tables in calculation of macronutrient contents in kindergarten meals. Findings: We established no correlation (P>0.05) between the value of proteins, fats and carbohydrates. Significant difference was established between the average content of proteins (t=2.57; P<0.05), and carbohydrates (t=3.20; P<0.01), but not with the content of fats in the meals (t=1.26; P>0.05) (food composition tables vs chemical analysis). Conclusion: Until we establish new food composition tables, chemical analysis remains the only valid method for assessment of macronutrients content and energy value of a meal in kindergarten.

Konstansa, Lazarevic; Dusica, Stojanovic; Dragan, Bogdanovic

2014-01-01

211

Predicting Chemical Fingerprints of Vadose Zone Soil Gas and Indoor Air from NonAqueous Phase Liquid Composition  

Microsoft Academic Search

Complex mixtures of volatile organic chemical (VOC) vapors can exist over subsurface accumulations of non-aqueous phase liquids (NAPLs) and contaminated soils. The ability to predict the relative soil gas chemical composition arising from such NAPLs is relevant to studies of the sources and fate of soil gas, and in assessing the possible intrusion of soil gas chemical constituents to indoor

Allen D. Uhler; Kevin J. McCarthy; Stephen D. Emsbo-Mattingly; Scott A. Stout; Gregory S. Douglas

2010-01-01

212

Chemical composition of black rockfish (Sebastes melanops) fillets and byproducts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Black rockfish are important in the near shore fishery of Southeast Alaska. They are the only species among the pelagic shelf rockfishes for which there is a directed fishery in state waters. The purpose of this study was to determine the composition black rockfish fillets and its major processing b...

213

To measure the chemical composition of a Near Earth Object  

Microsoft Academic Search

Introduction. Scenarios for a Near Earth Object (NEO) rendezvous mission were discussed recently in Europe. Such a mission would address scientific questions about the initial conditions and evolutionary history of the solar nebula, as well as mitigation considerations to prevent impact with the Earth. In our opinion the measurement of the elemental composition and the distribution of volatiles in the

Gasnault; A. Ball; J. Biele; C. D'Uston; O. Forni; G. Klingelhofer; S. Maurice; S. Ulamec

2006-01-01

214

Sensory assessment and chemical measurement of astringency of Greek wines: Correlations with analytical polyphenolic composition.  

PubMed

The purpose of this study was to measure the astringency of selected Greek red wines and to assess the relationship between sensory and chemical data. Nine red wines produced by three native Greek grape varieties (agiorgitiko, xinomavro and mavrodafni) were used and their astringency and bitterness was assessed by a trained panel. In addition, their astringency was estimated chemically employing the ovalbumin precipitation method. Their polyphenolic composition was also determined by High Performance Liquid Chromatography (HPLC). The sensory data showed that mandilaria was the most astringent variety whereas agiorgitiko was the least. Statistical analysis of the results indicated that the chemical data obtained for astringency significantly correlated with the sensory determinations. In addition, significant correlations were obtained between the sensory data and the wine polyphenolic composition. PMID:25213982

Kallithraka, S; Kim, D; Tsakiris, A; Paraskevopoulos, I; Soleas, G

2011-06-15

215

Chemical composition of AY Ceti: A flaring, spotted star with a white dwarf companion  

NASA Astrophysics Data System (ADS)

The detailed chemical composition of the atmosphere AY Cet (HD 7672) is determined from a high-resolution spectrum in the optical region. The main atmospheric parameters and the abundances of 22 chemical elements, including key species such as 12C, 13C, N, and O, are determined. A differential line analysis gives T_eff=5080 K, log g=3.0, [Fe/H]=-0.33, [C/Fe]=-0.17, [N/Fe]=0.17, [O/Fe]=0.05, C/N=1.58, and 12C/13C=21. Despite the high chromospheric activity, the optical spectrum of AY Cet provides a chemical composition typical for first ascent giants after the first dredge-up.

Tautvaišien?, G.; Barisevi?ius, G.; Berdyugina, S.; Ilyin, I.; Chorniy, Y.

2011-12-01

216

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

217

Chemical versus Electrochemical Synthesis of Carbon Nano-onion/Polypyrrole Composites for Supercapacitor Electrodes.  

PubMed

The development of high-surface-area carbon electrodes with a defined pore size distribution and the incorporation of pseudo-active materials to optimize the overall capacitance and conductivity without destroying the stability are at present important research areas. Composite electrodes of carbon nano-onions (CNOs) and polypyrrole (Ppy) were fabricated to improve the specific capacitance of a supercapacitor. The carbon nanostructures were uniformly coated with Ppy by chemical polymerization or by electrochemical potentiostatic deposition to form homogenous composites or bilayers. The materials were characterized by transmission- and scanning electron microscopy, differential thermogravimetric analyses, FTIR spectroscopy, piezoelectric microgravimetry, and cyclic voltammetry. The composites show higher mechanical and electrochemical stabilities, with high specific capacitances of up to about 800?F?g(-1) for the CNOs/SDS/Ppy composites (chemical synthesis) and about 1300?F?g(-1) for the CNOs/Ppy bilayer (electrochemical deposition). PMID:25736714

Mykhailiv, Olena; Imierska, Monika; Petelczyc, Martyna; Echegoyen, Luis; Plonska-Brzezinska, Marta E

2015-04-01

218

Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology  

PubMed Central

In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

2015-01-01

219

Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology.  

PubMed

In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

Reyes-Rivera, Jorge; Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos; Terrazas, Teresa

2015-01-01

220

Differences in Chemical Composition of Soil Organic Carbon Resulting From Long-Term Fertilization Strategies  

PubMed Central

Chemical composition of soil organic carbon (SOC) is central to soil fertility. We hypothesize that change in SOC content resulting from various long-term fertilization strategies accompanies the shift in SOC chemical structure. This study examined the effect of fertilization strategies along with the time of fertilizer application on the SOC composition by 13C nuclear magnetic resonance (NMR) spectroscopy. The soils (Aquic Inceptisol) subjected to seven fertilizer treatments were collected in 1989, 1999 and 2009, representing 0, 10 and 20 years of fertilization, respectively. The seven fertilizer treatments were (1–3) balanced fertilization with application of nitrogen (N), phosphorus (P) and potassium (K) including organic compost (OM), half organic compost plus half chemical fertilizer (1/2OM), and pure chemical NPK fertilizer (NPK); (4–6) unbalanced chemical fertilization without application of one of the major elements including NP fertilizer (NP), PK fertilizer (PK), and NK fertilizer (NK); and (7) an unamended control (CK). The SOC content in the balanced fertilization treatments were 2.3–52.6% and 9.4–64.6% higher than in the unbalanced fertilization/CK treatments in 1999 and 2009, respectively, indicating significant differences in SOC content with time of fertilizer application between the two treatment groups. There was a significantly greater proportion of O-alkyl C and a lower proportion of aromatic C in the balanced fertilization than in unbalanced fertilization/CK treatments in 1999, but not in 2009, because their proportions in the former treatments approached the latter in 2009. Principal component analysis further showed that the C functional groups from various fertilization strategies tended to become compositionally similar with time. The results suggest that a shift in SOC chemical composition may be firstly dominated by fertilization strategies, followed by fertilization duration. PMID:25884713

Li, Zengqiang; Zhao, Bingzi; Wang, Qingyun; Cao, Xiaoyan; Zhang, Jiabao

2015-01-01

221

Chemical composition of biodegradable dissolved organic matter in streamwater  

Microsoft Academic Search

Abstract Plug-flow biofilm reactors colonized,by microorganisms,in streamwater,were used to measure,the concentration and composition,of biodegradable,dissolved,organic C (BDOC) in White Clay Creek. During the 4-month study period, DOC ranged from 0.8 to 10.4 mg C liter-’ and was, on average, composed of 75% humic substances, 13% carbohydrates, 2% amino acids, and 18% > 100 kDa. The carbohydrates were predominantly polysaccharides, nearly all

Christian J. Volk; B. Volk; Louis A. Kaplan

222

Chemical Composition of Soils of Northwest and West Central Texas.  

E-print Network

[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... Grimes. M. S., Textiles lorticulture : Elizabeth D. Terrill, M. A., Nutrition S. H. Yarnell, Sc. D Chief Soil Survey: R. Hawthorn. M.'$., Horticulturist **W. T. Carter B. S Chief H. M. Reed, M. S., Horticulturist E. H. ~emplh, B. 'b., Soil Surveyor...

Fraps, G. S. (George Stronach)

1932-01-01

223

Chemical Composition and Physical Characteristics of Unpopped Popcorn Hybrids  

Microsoft Academic Search

Kernel number, individual kernel weight, individual kernel volume, crude fat, crude protein, reducing sugars, starch content, amylose\\/amylopectin ratio and fatty acid composition were determined for six popcorn hybrids, grown in Colorado or Nebraska and harvested in 1997. The popcorn hybrids were A358W, 353W, BKH, 019, 1601 and 5501. Also, popcorn hybrids were categorized based on their popped color and popped

Kenneth G. D. Allen; Frank R. Stermitz; Joseph A. Maga

2000-01-01

224

Composite chemical vapor deposition diamond anvils for high-pressure\\/high-temperature experiments  

Microsoft Academic Search

Composite diamond anvils have been developed for high-pressure\\/high-temperature measurements of diamond anvil cells. The anvils are fabricated using single-crystal chemical vapor deposition (CVD) from previously used and\\/or slightly damaged anvils made of natural or synthetic diamond. These composite anvils can be fabricated to possess optical characteristics at least comparable to conventional diamond anvils, whereas the single-crystal CVD portion is more

Chang-Sheng Zha; Szczesny Krasnicki; Yu-Fei Meng; Chih-Shiue Yan; Joseph Lai; Qi Liang; Ho-Kwang Mao; Russell J. Hemley

2009-01-01

225

Phase composition and morphology of TaC coating on carbon fibers by chemical vapor infiltration  

Microsoft Academic Search

Chemical vapor infiltration was applied to deposit TaC thin film on carbon fibers using TaCl5–Ar–C3H6–H2 source. The influence of temperature, pressure and addition of H2 on phase composition and morphology of the coating had been studied. The results showed that the composition of the coating changes with temperature. The films are mainly composed of TaC and C when deposited at

Zhao-ke Chen; Xiang Xiong; Bai-yun Huang; Guo-dong Li; Feng Zheng; Peng Xiao; Hong-bo Zhang; Jian Yin

2008-01-01

226

Chemical-vapor-infiltrated silicon nitride, boron nitride, and silicon carbide matrix composites  

Microsoft Academic Search

This paper reports composites of carbon\\/chemical-vapor-deposited (CVD) SiâNâ, carbon\\/CVD BN, mullite\\/CVD SiC, and SiC yarn\\/CVD SiC prepared to determine if there were inherent toughness in these systems. The matrices were deposited at high enough temperatures to ensure that they were crystalline, which should make them more stable at high temperatures. The fiber-matrix bonding in the C\\/SiâNâ composite appeared to be

R. D. Ventri; Francis S. Galasso

1990-01-01

227

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

228

Evaluation of hydroxylapatite\\/poly(l-lactide) composites: physico-chemical properties  

Microsoft Academic Search

The aim of this in vitro study was to examine the physico-chemical behaviour of hydroxylapatite\\/poly(l-lactide) (HA\\/PLLA) composites in solution tests. The polymer PLLA, the composites 30 wt% HA\\/PLLA (C30) and 50 wt% HA\\/PLLA (C50) and a one-side HA-coated PLLA (HAcP) were evaluated. Rectangular specimens were incubated in various acellular aqueous buffer solutions [citrate, Gomori's and phosphate-buffered saline (PBS)] up to

C. C. P. M. Verheyen; C. P. A. T. Klein; J. M. A. Blieck-Hogervorst; J. G. C. Wolke; C. A. Blitterswijn; K. Groot

1993-01-01

229

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

230

Chemically functionalized alumina nanoparticle effect on carbon fiber\\/epoxy composites  

Microsoft Academic Search

The effect of chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) on the performance of carbon fiber reinforced plastic (FRP) composite materials has been investigated. Lysine-alumoxane (L-alumoxane) and para-hydroxybenzoate-alumoxane (p-HB-alumoxane), formed from the reaction of boehmite with the appropriate carboxylic acid, can potentially react with epoxy resins to provide covalent bonding of the nanoparticles to the polymer lattice. Composite samples were prepared each

Naureen Shahid; Richard G. Villate; Andrew R. Barron

2005-01-01

231

Predicting the chemical composition and structure of Aspergillus nidulans hyphal wall surface by atomic force microscopy  

Microsoft Academic Search

In fungi, cell wall plays an important role in growth and development. Major macromolecular constituents of the aspergilli\\u000a cell wall are glucan, chitin, and protein. We examined the chemical composition and structure of the Aspergillus nidulans hyphal wall surface by an atomic force microscope (AFM). To determine the composition of the cell wall surface, the adhesion\\u000a forces of commercially available

Hyun-uk Lee; Jong Bae Park; Haeseong Lee; Keon-Sang Chae; Dong-Min Han; Kwang-Yeop Jahng

2010-01-01

232

The specific surface area and chemical composition of diamond dust near Barrow, Alaska  

E-print Network

mixing within the boundary layer can also lead to the formation of diamond dust [Curry et al., 1996; vanThe specific surface area and chemical composition of diamond dust near Barrow, Alaska Florent 2011; revised 22 September 2011; accepted 3 October 2011; published 14 December 2011. [1] Diamond dust

Douglas, Thomas A.

233

Improved interactions in chemically modified pineapple leaf fiber reinforced polyethylene composites  

Microsoft Academic Search

Mechanical properties of pineapple leaf fiber reinforced low density polyethylene composites have been studied with special reference to the effects of interface modifications. Various chemical treatments using reagents such as NaOH, PMPPIC, silane and peroxide were carried out to improve the interfacial bonding. Both infrared spectroscopy and SEM were used to characterize the interface and the modified fiber surface. It

Jayamol George; S. S. Bhagawan; Sabu Thomas

1997-01-01

234

Effects of temperature on the chemical composition and antioxidant activity of three strawberry cultivars  

Microsoft Academic Search

Three strawberry cultivars (Dover, Campineiro, and Oso Grande), grown in the same commercial plantation, were harvested at the ripe stage and stored at 6, 16 and 25 °C, for 6 days. During this period, chemical composition and antioxidant activity were evaluated. Results showed an increase in total soluble sugars, anthocyanin and vitamin C contents, indicating that a new biosynthesis had

Beatriz Rosana Cordenunsi; Maria Inés Genovese; João Roberto Oliveira do Nascimento; Neuza Mariko Aymoto Hassimotto; Ricardo José dos Santos; Franco Maria Lajolo

2005-01-01

235

IR spectral analysis of the chemical composition of the lichen Hypogymnia physodes to assess atmospheric pollution  

Microsoft Academic Search

We have studied the level of atmospheric pollution in different urban recreational areas using analysis of the chemical composition\\u000a of the lichen Hypogymnia physodes by Fourier transform IR (FTIR) spectroscopy. We have developed a procedure for determining the dominant pollutant, its concentration,\\u000a and the degree of its impact on the structure of the lichen.

A. F. Meisurova; S. D. Khizhnyak; P. M. Pakhomov

2009-01-01

236

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

237

Chemical composition of atmospheric aerosols over the Indian Ocean: impact of continental advection  

Microsoft Academic Search

The advection of continental aerosols over to the marine environments of Indian Ocean and Arabian Sea during northern hemispheric winter have been studied based on the chemical composition of aerosols collected from these regions. The aerosol samples collected on INDOEX cruise were analysed for anions like SO4, NO3 and Cl and cations of Na, K, Mg, Mn, Zn, Fe, Cu,

P. R Nair; K. Parameswaran; S. V. Sunilkumar; A. Abraham; S. Jacob

2004-01-01

238

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

239

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...

240

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...

241

Studies on the chemical composition–creep-rupture strength relation for heat-resistant nickel alloys  

Microsoft Academic Search

The results of creep-rupture data processing for heat-resistant nickel alloys by parametric methods, by the Trunin and base\\u000a diagram methods are presented. The line of investigations to establish the relation between the chemical composition and creep\\u000a rupture strength is considered.

V. V. Krivenyuk; R. I. Kuriat; G. V. Mukhopad; S. G. Kiselevskaya

2011-01-01

242

Chemically vapor deposited diamond-tipped one-dimensional nanostructures and nanodiamondsilicananotube composites  

E-print Network

with nanodiamond particles. SEM, Raman spectroscopy, and EDX were used to analyze the composite. Wet chemical-some years [1­3]. Various energy sources including hot metal surfaces, electrical discharges, combustion was found critical to preferentially depositing diamond phase of carbon. By enhancing the bombardment

Wilamowski, Bogdan Maciej

243

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

244

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

245

Chemical modification of poly(p-phenylene) for use in ablative compositions  

NASA Technical Reports Server (NTRS)

Development of ablative materials based on modification of polyphenylene compounds is discussed. Chemical and physical properties are analyzed for application as heat resistant materials. Synthesis of linear polyphenylenes is described. Effects of exposure to oxyacetylene flame and composition of resultant char layer are presented.

Parker, J. A.; Heimbuch, A. H.; Vincent, D. N.; Hammermesh, C. L.

1972-01-01

246

Author's personal copy Chemical and isotopic composition of high-molecular-weight dissolved organic  

E-print Network

Author's personal copy Chemical and isotopic composition of high-molecular-weight dissolved organic of high-molecular-weight dissolved organic matter (HMW-DOM) in the mixing zone of the Mississippi River and transported in the high-molecular-weight (HMW) or colloidal phase

Guo, Laodong

247

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

248

Hypertrophy of colonic smooth muscle: structural remodeling, chemical composition, and force output  

E-print Network

Hypertrophy of colonic smooth muscle: structural remodeling, chemical composition, and force output,) to longer lengths, and no change in force per square centimeter; 2) hypertrophy and hyperplasia of both of hollow organs can show remarkable plasticity, as exemplified by hypertrophy. Hypertrophy generally occurs

Trinkle-Mulcahy, Laura

249

Chemical compositions, fine structure and physicochemical properties of kudzu ( Pueraria lobata) starches from different regions  

Microsoft Academic Search

Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1%

Pham Van Hung; Naofumi Morita

2007-01-01

250

Influence of processing and chemical treatment of flax fibres on their composites  

Microsoft Academic Search

During the consecutive decortication stages of flax fibres (retting, scutching, hackling, …), the fibre properties change tremendously due to mechanical and chemical modifications. This study points out the influence of the flax processing parameters, and consequently of the fibre properties, on the mechanical properties of flax fibre reinforced epoxy composites. The better the retting degree of the fibres, the better

I. Van de Weyenberg; J. Ivens; A. De Coster; B. Kino; E. Baetens; I. Verpoest

2003-01-01

251

Plasma induced microstructural, compositional, and resistivity changes in ultrathin chemical vapor deposited titanium nitride films  

Microsoft Academic Search

Extremely thin titanium nitride (TiN) barrier layers for Cu based interconnects were deposited using metal organic chemical vapor deposition. The effect of the subsequently performed nitrogen\\/hydrogen plasma treatment on the microstructure, composition, and electrical properties of these films is studied using conventional and high resolution transmission electron microscopy, Auger electron spectroscopy, and four point probe resistivity measurements. In the studied

R. Kröger; M. Eizenberg; C. Marcadal; L. Chen

2002-01-01

252

The influence of chemical composition on vaporisation of LNG and LPG on unconfined water surfaces  

Microsoft Academic Search

A model is proposed for estimating the rate of vaporisation of LNG and LPG cryogen mixtures spreading on unconfined water surfaces. The model is used to examine the influence of chemical composition on the vaporisation rate of LNG and LPG during spreading. Calculations have been performed whereby the vaporisation rate of the LNG and LPG mixtures has been compared to

C. Conrado; V. Vesovic

2000-01-01

253

PhysicoChemical Properties, Composition and Oxidative Stability of Camelina sativa Oil  

Microsoft Academic Search

Summary Camelina sativa is a cruciferous oilseed plant. With the aim of describing the general characteristics of the oil obtained from the seeds of plants grown in Slovenia and of com- paring it to camelina oil from other countries we determined some physico-chemical pro- perties, fatty acid composition, iodine and saponification value and followed its oxidative stability under different storage

Veronika Abram

2005-01-01

254

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

255

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

256

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

257

Friction performance of C\\/C composites prepared using rapid directional diffused chemical vapor infiltration processes  

Microsoft Academic Search

A technology used to prepare C\\/C composites using a rapid directional diffused (RDD) chemical vapor infiltration process has been investigated. General RDD technologies were explored, and optimal parameters were determined. The friction and wear properties of this material were researched. The results showed that in the RDD process, propylene and nitrogen were rapidly and directionally diffused into the carbon preforms

Ruiying Luo

2002-01-01

258

Densification of unidirectional carbon–carbon composites by isothermal chemical vapor infiltration  

Microsoft Academic Search

The aim of this research was to investigate the densification of cylindrical unidirectional C–C composites by isothermal chemical vapor infiltration. Several different preforms with different fiber volume fractions were prepared, and it was found that the preforms with the lower fiber volume fraction have a more rapid rate of densification and the final density is higher. The problem of infiltrating

He-Jun Li; Xiang-Hui Hou; Yi-Xi Chen

2000-01-01

259

Atmospheric precipitation and chemical composition of an urban site, Guaíba hydrographic basin, Brazil  

Microsoft Academic Search

The purpose of the present work was to study the chemical composition of bulk and wet atmospheric precipitation in the Guaíba Hydrographic Basin, in South Brazil. The samples were analyzed from January to December 2002 at three different stations, i.e., 8° Distrito and CEASA stations in the city of Porto Alegre, and Charqueadas station, located in the city of same

D. Migliavacca; E. C. Teixeira; F. Wiegand; A. C. M. Machado; J. Sanchez

2005-01-01

260

Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical vapor deposition  

E-print Network

Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical of the surface was observed, N-polarity indium nitride is indicated. © 2006 American Institute of Physics. DOI: 10.1063/1.2187513 Research on the growth and characterization of indium nitride InN has increased

Dietz, Nikolaus

261

The ideal ceramic-fibre\\/oxide-matrix composite: how to reconcile antagonist physical and chemical requirements?  

Microsoft Academic Search

Starting with a short historical introduction, this paper deals with the search for the best materials to be used in ceramic composites. The reinforcement and oxide matrix must satisfy multiple - and often antagonist - requirements in terms of physical (failure resistance, damage tolerance) and chemical (thermal stability, corrosion resistance) properties. The best compromise is obtained by \\

Philippe Colomban; Gwénael Gouadec

2005-01-01

262

LETTER doi:10.1038/nature13000 Change in the chemical composition of infalling gas  

E-print Network

at the centrifugal barrier of the infalling gas (that is, half the centrifugal radius). In fact, the observed maximumLETTER doi:10.1038/nature13000 Change in the chemical composition of infalling gas forming a disk is expected to form7,8 . The interstellar gas, mainly con- sistingofhydrogenmolecules

Cai, Long

263

Antarctic saline lakes--stable isotopic ratios, chemical compositions and evolution  

Microsoft Academic Search

About 90 saline and fresh water lakes as well as glaciers and their melt waters from the ice-free areas of the Soya Coast, the Vestfold Hills and the Southern Victoria Land of Antarctica have been analyzed for hydrogen and oxygen isotopic ratios. These results and the chemical compositions so far published indicate four types of saline lakes. 1. (1) Three

Osamu Matsubaya; Hitoshi Sakai; Tetsuya Torii; Harry Burton; Knowles Kerry

1979-01-01

264

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

265

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...

266

Controlled way to prepare quasi-1D nanostructures with complex chemical composition in porous anodic alumina.  

PubMed

Herein we propose a novel approach to the preparation of quasi-1D nanostructures with various chemical compositions based on infiltration of colloidal solution into the asymmetric anodic alumina membrane. The proposed technique was successfully applied for the preparation of ordered arrays of the magnetically hard anisotropic hexaferrite nanostructures. PMID:21165480

Lukatskaya, Maria R; Trusov, Lev A; Eliseev, Andrey A; Lukashin, Alexey V; Jansen, Martin; Kazin, Pavel E; Napolskii, Kirill S

2011-02-28

267

Determination of the chemical composition of human renal stones with MDCT: influence of the surrounding media  

NASA Astrophysics Data System (ADS)

The selection of the optimal treatment method for urinary stones diseases depends on the chemical composition of the stone and its corresponding fragility. MDCT has become the most used modality to determine rapidly and accurately the presence of stones when evaluating urinary lithiasis treatment. That is why several studies have tempted to determine the chemical composition of the stones based on the stone X-ray attenuation in-vitro and invivo. However, in-vitro studies did not reproduce the normal abdominal wall and fat, making uncertain the standardization of the obtained values. The aim of this study is to obtain X-ray attenuation values (in Hounsfield Units) of the six more frequent types of human renal stones (n=217) and to analyze the influence of the surrounding media on these values. The stones were first placed in a jelly, which X-ray attenuation is similar to that of the human kidney (30 HU at 120 kV). They were then stuck on a grid, scanned in a water tank and finally scanned in the air. Significant differences in CT-attenuation values were obtained with the three different surrounding media (jelly, water, air). Furthermore there was an influence of the surrounding media and consequently discrepancies in determination of the chemical composition of the renal stones. Consequently, CT-attenuation values found in in-vitro studies cannot really be considered as a reference for the determination of the chemical composition except if the used phantom is an anthropomorphic one.

Grosjean, Romain; Sauer, Benoît; Guerra, Rui; Kermarrec, Isabelle; Ponvianne, Yannick; Winninger, Daniel; Daudon, Michel; Blum, Alain; Felblinger, Jacques; Hubert, Jacques

2007-03-01

268

Chemical composition and degradation characteristics of foliage of some African multipurpose trees  

Microsoft Academic Search

Samples of foliage from multipurpose leguminous trees (MPT) which had been selected as potential feed supplements for ruminants were examined for their chemical composition and in situ degradation characteristics, and were compared with alfalfa (Medicago sativa) hay and teff (Eragrostis abyssinica) straw. Organic matter (OM), acid detergent fibre (ADF), neutral detergent fibre (NDF), nitrogen, neutral detergent nitrogen, acid detergent lignin

S. M El hassan; A Lahlou Kassi; C. J Newbold; R. J Wallace

2000-01-01

269

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...

270

AGE, SIZE, GROWTH, AND CHEMICAL COMPOSITION OF ATLANTIC MENHADEN, BREVOORTIA TYRANNUS, FROM  

E-print Network

AGE, SIZE, GROWTH, AND CHEMICAL COMPOSITION OF ATLANTIC MENHADEN, BREVOORTIA TYRANNUS, FROM ABSTRACT Age and size were determined for 2,015 Atlantic menhaden caught in Narragansett Bay, R.I., during 1976. Atlantic menhaden were predominantly age 2 and age 3, and in all age groups were significantly

271

CCN closure study: Effects of aerosol chemical composition and mixing state  

NASA Astrophysics Data System (ADS)

This study presents a detailed cloud condensation nuclei (CCN) closure study that investigates the effects of chemical composition (bulk and size resolved) and mixing state (internal and external) on CCN activity of aerosols. Measurements of the chemical composition, aerosol size distribution, total number concentration, and CCN concentration at supersaturation (SS = 0.2-1.0%) were performed during the winter season in Kanpur, India. Among the two cases considered here, better closure results are obtained for case 1 (low total aerosol loading, 49.54 ± 26.42 ?g m-3, and high O:C ratio, 0.61 ±0.07) compared to case 2 (high total aerosol loading, 101.05 ± 18.73 ?g m-3, and low O:C ratio, 0.42 ±0.06), with a maximum reduction of 3-81% in CCN overprediction for all depleted SS values (0.18-0.60%). Including the assumption that less volatile oxidized organic aerosols represent the soluble organic fraction reduced the overprediction to at most 40% and 129% in the internal and external mixing scenarios, respectively. At higher depleted SS values (0.34-0.60%), size-resolved chemical composition with an internal mixing state performed well in CCN closure among all organic solubility scenarios. However, at a lower depleted SS value (0.18%), closure is found to be more sensitive to both the chemical composition and mixing state of aerosols. At higher SS values, information on the solubility of organics and size-resolved chemical composition is required for accurate CCN predictions, whereas at lower SS values, information on the mixing state in addition to the solubility of organics and size-resolved chemical composition is required. Overall, ?total values are observed to be independent of the O:C ratio [?total= (0.36 ±0.01) × O:C - (0.03 ± 0.01)] in the range of 0.2chemical composition of aerosols is not well represented by the changes in the O:C ratio alone.

Bhattu, Deepika; Tripathi, S. N.

2015-01-01

272

On the interpretation of age and chemical composition of composite stellar populations determined with line-strength indices  

E-print Network

We study the simple-stellar-population-equivalent (SSP-equivalent) age and chemical composition measured from the Lick/IDS line-strength indices of composite stellar populations (CSP). We build two sets of ~30000 CSP models using stellar populations synthesis models, combining an old population and a young population with a range of ages and chemical compositions representative of early-type galaxies. We investigate how the SSP-equivalent stellar parameters of the CSP's depend on the stellar parameters of the two input populations; how they depend on V-band luminosity-weighted stellar parameters; and how SSP-equivalent parameters derived from different Balmer-line indices can be used to reveal the presence of a young population on top of an old one. We find that the SSP-equivalent age depends primarily on the age of the young population and on the mass fraction of the two populations, and that the SSP-equivalent chemical composition depends mainly on the chemical composition of the old population. Furthermore, while the SSP-equivalent chemical composition tracks quite closely the V-band luminosity weighted one, the SSP-equivalent age does not and is strongly biased towards the age of the young population. In this bias the age of the young population and the mass fraction between old and young population are degenerate. Finally, assuming typical error bars, we find that a discrepancy between the SSP-equivalent parameters determined with different Balmer-line indices can reveal the presence of a young stellar population on top of an old one as long as the age of the young population is less than ~2.5 Gyr and the mass fraction of young to old population is between 1% and 10%. Such disrepancy is larger at supersolar metallicities.

Paolo Serra; Scott C. Trager

2006-10-11

273

Characterization of chemical composition of bee pollen in China.  

PubMed

Bee pollen has been praised for its good nutrition and therapeutic values. China is the largest producer in the world. Twelve common varieties of monofloral bee pollen collected from China's main producing regions were selected for nutritional composition analysis, including proximate contents, dietary fibers, amino acid distribution, fatty acid composition, and mineral elements. The proximate compositions mostly met the specifications regulating pollen load quality of China. Proline and glutamic acids were found to be the predominant amino acids in the form of both total amino and free amino acids. Lysine was the relative limiting amino acid. The percentage of total essential amino acids (TEAA) to total amino acids (TAA) reached the nutrition recommendation of the Food and Agricultural Organization (FAO). The major fatty acids, presented as mean values, were C18:3 (25.1%), C16:0 (19.6%), C18:1 (17.3%), C18:2 (8.78%), C22:0 (4.07%), and C18:0 (2.96%) acids. The proportions of C18:3 were generally higher than those of C18:2, and the ratio of total unsaturated fatty acids (TUS) to total saturated fatty acids (TS) was >1.0, except for Nelumbo nucifera Gaertn. pollen for the characteristic absence of C18:3 acids. High levels of beneficial elements such as K, Ca, Mg, Zn, Fe, Mn. and Cu were observed in pollen samples. The contents of detrimental trace elements of Cd, Pb, and Hg were primarily lower or not detected. However, more attention should be paid to a large amount of Al, with a concentration of >100 mg/kg DW in most samples. There were some significant differences between samples. On the whole, the Chinese bee pollen was evaluated as a good complement to diet. PMID:23265625

Yang, Kai; Wu, Dan; Ye, Xingqian; Liu, Donghong; Chen, Jianchu; Sun, Peilong

2013-01-23

274

Testing chemical composition of highest energy comic rays  

E-print Network

We study basic characteristics of distributions of the depths of shower maximum in air showers caused by cosmic rays with the highest energies. The consistency between their average values and widths, and their energy dependences are discussed within a simple phenomenological model of shower development independently of assumptions about detailed features of high--energy interactions. It is shown that reliable information on primary species can be derived within a partition method. We present examples demonstrating implications for the changes in mass composition of primary cosmic rays.

Nosek, D; Noskova, J; Ebr, J

2013-01-01

275

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

2015-05-01

276

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

277

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

278

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

279

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

280

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

281

Chemical Weathering  

NSDL National Science Digital Library

This tombstone weathering lab is designed to provide students with tangible understanding of chemical weathering and weathering rates. To prepare for this lab, students will have learned in previous labs to identify common minerals and rocks and will have attended lectures about the process of chemical weathering. During the first part of the lab we travel to the city cemetery to collect data on the age and extent of chemical weathering of tombstones that are made of limestone and igneous rocks. After collecting data for ~1 hour, we return to the computer lab where students use Microsoft Excel to analyze and interpret their data. Their task is to calculate a chemical weathering rate for limestone for our region and compare that rate to those from other regions. This activity gives students experience in the process of scientific inquiry: data collection, data analysis and data interpretation. Students develop Microsoft Excel skills: writing formulas, producing charts, understanding trendlines and R2 values.

Kira Lawrence

282

Chemical Emergency  

MedlinePLUS

... Landslide Pet Safety Poisoning Power Outage Terrorism Thunderstorm Tornado Tsunami Volcano Water Safety Wildfire Winter Storm Tools ... and your family is to be prepared. In Case of Poisoning The most common home chemical emergencies ...

283

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

284

Nanoscale chemical interaction enhances the physical properties of bioglass composites.  

PubMed

Bioglasses are favorable biomaterials for bone tissue engineering; however, their applications are limited due to their brittleness. In addition, the early failure in the interface is a common problem of composites of bioglass and a polymer with high mechanical strength. This effect is due to the phase separation, nonhomogeneous mixture, nonuniform mechanical strength, and different degradation properties of two compounds. To address these issues, in this study a nanoscale interaction between poly(methyl methacrylate) (PMMA) and bioactive glass was formed via silane coupling agent (3-trimethoxysilyl)propyl methacrylate (MPMA). A monolith was produced at optimum composition from this hybrid by the sol-gel method at 50 °C with a rapid gelation time (<50 min) that possessed superior physicochemical properties compared to pure bioglass and physical mixture. For instance, the Young's modulus of bioglass was decreased 40-fold and the dissolution rate of silica was retarded 1.5-fold by integration of PMMA. Prolonged dissolution of silica fosters bone integration due to the continuous dissolution of bioactive silica. The primary osteoblast cells were well anchored and cell migration was observed on the surface of the hybrid. The in vivo studies in mice demonstrated that the integrity of the hybrids was maintained in subcutaneous implantation. They induced mainly a mononuclear phagocytic tissue reaction with a low level of inflammation, while bioglass provoked a tissue reaction with TRAP-positive multinucleated giant cells. These results demonstrated that the presence of a nanoscale interaction between bioglass and PMMA affects the properties of bioglass and broadens its potential applications for bone replacement. PMID:24001050

Ravarian, Roya; Zhong, Xia; Barbeck, Mike; Ghanaati, Shahram; Kirkpatrick, Charles James; Murphy, Ciara M; Schindeler, Aaron; Chrzanowski, Wojciech; Dehghani, Fariba

2013-10-22

285

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

286

Chemical reactions between aluminum and fly ash during synthesis and reheating of Al-fly ash composite  

Microsoft Academic Search

Thermodynamic analysis indicates that there is the possibility of chemical reactions between aluminum melt and cenosphere\\u000a fly ash particles. These particles contain alumina, silica, and iron oxide, which, during solidification processing of aluminum-fly\\u000a ash composites or during holding of such composites at temperatures above the melting temperature of aluminum, are likely\\u000a to undergo chemical reduction. These chemical reactions between the

R. O. Guo; P. K. Rohatgi

1998-01-01

287

The chemical compositions of Galactic disc F and G dwarfs  

NASA Astrophysics Data System (ADS)

Photospheric abundances are presented for 27 elements from carbon to europium in 181 F and G dwarfs from a differential local thermodynamic equilibrium (LTE) analysis of high-resolution and high signal-to-noise ratio spectra. Stellar effective temperatures (Teff) were adopted from an infrared flux method calibration of Strömgren photometry. Stellar surface gravities (g) were calculated from Hipparcos parallaxes and stellar evolutionary tracks. Adopted Teff and g values are in good agreement with spectroscopic estimates. Stellar ages were determined from evolutionary tracks. Stellar space motions (U, V, W) and a Galactic potential were used to estimate Galactic orbital parameters. These show that the vast majority of the stars belong to the Galactic thin disc. Relative abundances expressed as [X/Fe] generally confirm previously published results. We give results for C, N, O, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd and Eu. The ? elements - O, Mg, Si, Ca and Ti - show [?/Fe] to increase slightly with decreasing [Fe/H]. Heavy elements with dominant contributions at solar metallicity from the s-process show [s/Fe] to decrease slightly with decreasing [Fe/H]. Scatter in [X/Fe] at a fixed [Fe/H] is entirely attributable to the small measurement errors, after excluding the few thick disc stars and the s-process-enriched CH subgiants. Tight limits are set on `cosmic' scatter. If a weak trend with [Fe/H] is taken into account, the composition of a thin disc star expressed as [X/Fe] is independent of the star's age and birthplace for elements contributed in different proportions by massive stars (Type II supernovae), exploding white dwarfs (Type Ia supernovae) and asymptotic red giant branch stars. By combining our sample with various published studies, comparisons between thin and thick disc stars are made. In this composite sample, thick disc stars are primarily identified by their VLSR in the range -40 to -100 km s-1. These are very old stars with origins in the inner Galaxy and metallicities [Fe/H]<=-0.4. At the same [Fe/H], the sampled thin disc stars have VLSR~ 0 km s-1, and are generally younger with a birthplace at about the Sun's Galactocentric distance. In the range -0.35 >=[Fe/H]>=-0.70, well represented by present thin and thick disc samples, [X/Fe] of the thick disc stars is greater than that of thin disc stars for Mg, Al, Si, Ca, Ti and Eu. [X/Fe] is very similar for the thin and thick disc for - notably - Na and iron-group elements. Barium ([Ba/Fe]) may be underabundant in thick relative to thin disc stars. These results extend previous ideas about composition differences between the thin and thick disc.

Reddy, Bacham E.; Tomkin, Jocelyn; Lambert, David L.; Allende Prieto, Carlos

2003-03-01

288

Non-destructive and rapid analysis of chemical compositions in Thai steamed pork sausages by near-infrared spectroscopy  

Microsoft Academic Search

The objective of the present study was to evaluate the ability of near-infrared (NIR) spectroscopy to predict chemical compositions of Thai steamed pork sausages in relation to different types of sample presentation forms of NIR measurements (with and without plastic casing). NIR spectra of sausages were scanned to predict the chemical compositions, protein, fat, ash and carbohydrate non-destructively. NIR spectrum

Pitiporn Ritthiruangdej; Ronnarit Ritthiron; Hideyuki Shinzawa; Yukihiro Ozaki

2011-01-01

289

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

290

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

291

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

Code of Federal Regulations, 2014 CFR

...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

292

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

293

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

294

Propagation and Chemical Composition of Ultra High Energy Cosmic Rays  

E-print Network

Extragalactic cosmic ray protons with an injection spectrum of the type $E^{-2.7}$ show a spectrum on earth with a dip due to the Bethe-Heitler pair production against the photons of the cosmic microwave background. The dip is produced in the energy region $10^{18} - 4\\times 10^{19}$ eV with position and shape that reproduce with high accuracy the spectrum observed experimentally. This interpretation of the observed data predicts the existence of an energy scale that signals a possible transition from galactic to extragalactic cosmic rays. In fact, at energies lower than a characteristic value $E_c\\approx 1\\times 10^{18}$ eV, determined by the equality between the rate of energy losses due to pair production and adiabatic losses, the spectrum of cosmic rays flattens in all cases of interest. In this model, the transition from galactic to extragalactic cosmic rays occurs at some energy below $E_c$, corresponding to the position of the so-called second knee. Another viable explanation of the observed data is based on a completely different approach assuming a mixed composition with protons and nuclei at energies $E\\ge 10^{19}$ eV. This scenario implies a transition from galactic to extragalactic cosmic rays at the ankle energies ($\\sim 10^{19}$ eV). In the present paper we will review the main features of the dip model comparing it with the model of transition at the ankle.

Roberto Aloisio

2007-01-22

295

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

296

Chemical composition of essential oils and aromatic waters from different Italian Anthemis maritima populations.  

PubMed

The chemical composition of the essential oils and aromatic waters isolated from six Italian Anthemis maritima populations was determined by GC-FID and GC/MS analyses. In total, 122 and 100 chemical compounds were identified in the essential oils and the aromatic waters, respectively. The main compound classes represented in the oils were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, and terpene esters. Multivariate chemometric techniques such as cluster analysis (CA) and principal coordinate analysis (PCO) were used to classify the samples according to the geographical origin. Statistical analysis allowed the attribution of the analyzed populations to different chemotype groups. PMID:24078600

Ciccarelli, Daniela; Noccioli, Cecilia; Pistelli, Luisa

2013-09-01

297

Effect of chemical treatment of Kevlar fibers on mechanical interfacial properties of composites.  

PubMed

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 (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system. PMID:16290785

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

2002-08-01

298

[Study on the chemical compositions of VOCs emitted by cooking oils based on GC-MS].  

PubMed

Volatile organic compounds (VOCs) are key precursors of ozone and secondary organic aerosols in air, and the differences in the compositions of VOCs lead to their different contribution to atmospheric reaction. Cooking oil fume is one of the important sources of atmospheric VOCs, and its chemical compositions are distinct under different conditions of oil types, food types, cooking methods and heating temperatures etc. In this study, the production of cooking oil fume was simulated by heating typical pure vegetable oils (peanut oil, sunflower oil, soybean oil, olive oil and blend oil) at different temperatures in beakers to investigate the chemical compositions of VOCs. The emitted VOCs were sampled with a Tenax adsorption tube and analyzed using GC-MS after thermal desorption. According to spectral library search and map analysis, using area normalized semi-quantitative method, preliminary qualitative and quantitative tests were conducted for the specific components of VOCs under different conditions. PMID:24640897

He, Wan-Qing; Nie, Lei; Tian, Gang; Li, Jing; Shao, Xia; Wang, Min-Yan

2013-12-01

299

Effect of chemical treatments on flax fibre reinforced polypropylene composites on tensile and dome forming behaviour.  

PubMed

Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

2015-01-01

300

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

301

Chemical composition of nuts and seeds sold in Korea.  

PubMed

Eleven types of nuts and seeds were analyzed to determine their energy (326-733 mg), moisture (1.6-18.3 mg), carbohydrate (8.8-70.9 mg), protein (4.9-30.5 mg), lipid (2.5-69.8 mg), and ash (1.2-5.5 mg) contents per 100 g of sample. Energy content was highest in pine nuts (733 mg/100 g), carbohydrate level was highest in dried figs (70.9 mg/100 g) and protein was highest in peanuts (30.5 mg/100 g). The amino acid compositions of nuts and seeds were characterized by the dominance of hydrophobic (range = 1,348.6-10,284.6 mg), hydrophilic (range = 341.1-3,244.3 mg), acidic (range = 956.1-8,426.5 mg), and basic (range = 408.6-4,738.5 mg) amino acids. Monounsaturated fatty acids (MUFA) were highest in macadamia nuts (81.3%), whereas polyunsaturated fatty acids (PUFA) were highest in the walnuts (76.7%). Macadamia nuts did not contain any vitamin E, whereas sunflower seeds contained the highest level (60.3 mg/kg). Iron (Fe) content was highest in pumpkin seeds (95.85 ± 33.01 ppm), zinc (Zn) content was highest in pistachios (67.24 ± 30.25 ppm), copper (Cu) content was greatest in walnuts (25.45 ± 21.51 ppm), and lead (Pb) content was greatest in wheat nuts (25.49 ± 4.64 ppm), significantly (P < 0.05). In conclusion, current commercial nuts and seeds have no safety concerns, although further analysis of Pb contents is necessary to ensure safety. PMID:23610599

Chung, Keun Hee; Shin, Kyung Ok; Hwang, Hyo Jeong; Choi, Kyung-Soon

2013-04-01

302

Chemical composition of nuts and seeds sold in Korea  

PubMed Central

Eleven types of nuts and seeds were analyzed to determine their energy (326-733 mg), moisture (1.6-18.3 mg), carbohydrate (8.8-70.9 mg), protein (4.9-30.5 mg), lipid (2.5-69.8 mg), and ash (1.2-5.5 mg) contents per 100 g of sample. Energy content was highest in pine nuts (733 mg/100 g), carbohydrate level was highest in dried figs (70.9 mg/100 g) and protein was highest in peanuts (30.5 mg/100 g). The amino acid compositions of nuts and seeds were characterized by the dominance of hydrophobic (range = 1,348.6-10,284.6 mg), hydrophilic (range = 341.1-3,244.3 mg), acidic (range = 956.1-8,426.5 mg), and basic (range = 408.6-4,738.5 mg) amino acids. Monounsaturated fatty acids (MUFA) were highest in macadamia nuts (81.3%), whereas polyunsaturated fatty acids (PUFA) were highest in the walnuts (76.7%). Macadamia nuts did not contain any vitamin E, whereas sunflower seeds contained the highest level (60.3 mg/kg). Iron (Fe) content was highest in pumpkin seeds (95.85 ± 33.01 ppm), zinc (Zn) content was highest in pistachios (67.24 ± 30.25 ppm), copper (Cu) content was greatest in walnuts (25.45 ± 21.51 ppm), and lead (Pb) content was greatest in wheat nuts (25.49 ± 4.64 ppm), significantly (P < 0.05). In conclusion, current commercial nuts and seeds have no safety concerns, although further analysis of Pb contents is necessary to ensure safety. PMID:23610599

Shin, Kyung Ok; Hwang, Hyo Jeong; Choi, Kyung-Soon

2013-01-01

303

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

304

Effect of aerosol chemical composition on CCN concentration and aerosol first indirect radiative forcing  

NASA Astrophysics Data System (ADS)

Previous studies have shown that compared to chemical composition, aerosol size distribution is the more dominant parameter on CCN activation [Feingold, GRL 2003; Dusek et al, Science, 2006]. In this study, the effects of aerosol chemical composition on CCN concentration is first characterized using data collected at Point Reyes, California during the Marine Stratus Experiment (MASE) in July 2005. Using simultaneous aerosol size distribution and CCN concentration measurements, we derived the 50% cut off diameter Dp,50 (i.e. particle diameter at which 50% particles are activated), which ranged from 98 to 136 nm at 0.18% and 52 to 66 nm at 0.43% supersaturation. The variation of Dp,50 at a fixed supersaturation reflects the change of aerosol chemical composition during the MASE. To evaluate the effect of aerosol chemical composition on the CCN concentration (Nccn), we recalculated the Nccn using each measured aerosol size distribution and Dp,50 averaged over the campaign, and compared it to direct CCN measurements. It was found that neglecting the variation of chemical composition (i.e. Dp,50) at Point Reyes leads to an error of 20% on Nccn at 0.18% supersaturation. For assumed global distributions of marine stratus clouds, such an error in Nccn corresponds to an error of 0.4 Wm-2 in estimation of the aerosol first indirect effect on the radiation budget. The effect of aerosol chemical composition on Nccn was also studied by examining the sensitivity of Nccn to particle activation diameter, defined as dlnNccn/dlnDp,50. The sensitivity, which strongly depends on the shape of aerosol size distribution, was analyzed for major aerosol types including the marine background aerosol. Previous measurements have shown the size distribution of marine background aerosol often consists of an Aitkin mode and an accumulation mode, separated by a valley referred to as "Hoppel minimum". It is general agreed that the accumulation mode and the Hoppel minimum are result of cloud processing of aerosols. Marine background aerosol measured during previous studies exhibit a sensitivity that often reaches a local minimum at the Hoppel minimum, which approximates the particle activation diameter at the supersaturation in marine status clouds. As a result, the error in CCN concentration introduced by using the average chemical composition (i.e. neglecting the variation of chemical composition) is low for marine background aerosol, and the resulting error in the aerosol first indirect radiative forcing is mostly below 0.2 Wm-2. Compared to marine background aerosol, the sensitivities of other major aerosol types are often much higher, and the error in the aerosol first indirect radiative forcing introduced by neglecting the variation of aerosol chemical composition are larger, which are consistent with the results from MASE measurements.

Wang, J.

2006-12-01

305

Chemical composition and acute toxicity in the water after in situ burning--a laboratory experiment.  

PubMed

The chemical composition and toxicity of a water soluble fraction (WSF) of oil versus the underlying water after in situ burning (ISB), has been studied in a laboratory experiment. A system for allowing water sampling after ISB was developed. Seawater samples and oil were collected prior to and immediately after ISB, and chemical analysis was conducted. The chemical characterization of the water showed that the disappearance of water soluble oil components during ISB was insignificant. Acute toxicity tests with the marine copepod Calanus finmarchicus and Microtox® bioassay was performed to establish LC(50)/EC(50) values of the water. The results were compared with regular WAF systems with unburned weathered oil, and indicated no increase in toxicity in the underlying water after ISB. PMID:22112284

Faksness, Liv-Guri; Hansen, Bjørn Henrik; Altin, Dag; Brandvik, Per Johan

2012-01-01

306

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.; A´undez, M.; Selsis, F.; Tessenyi, M.; Decin, L.

2014-12-01

307

Influence of different parameters on the chemical composition of warm neptunes  

E-print Network

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.

Olivia, Venot; Franck, Selsis; Marcell, Tessenyi; Leen, Decin

2014-01-01

308

Multivariate Quantitative Chemical Analysis  

NASA Technical Reports Server (NTRS)

Technique of multivariate quantitative chemical analysis devised for use in determining relative proportions of two components mixed and sprayed together onto object to form thermally insulating foam. Potentially adaptable to other materials, especially in process-monitoring applications in which necessary to know and control critical properties of products via quantitative chemical analyses of products. In addition to chemical composition, also used to determine such physical properties as densities and strengths.

Kinchen, David G.; Capezza, Mary

1995-01-01

309

Enamels in stained glass windows: Preparation, chemical composition, microstructure and causes of deterioration  

NASA Astrophysics Data System (ADS)

Stained glass windows incorporating dark blue and purple enamel paint layers are in some cases subject to severe degradation while others from the same period survived the ravages of time. A series of dark blue, green-blue and purple enamel glass paints from the same region (Northwestern Europe) and from the same period (16-early 20th centuries) has been studied by means of a combination of microscopic X-ray fluorescence analysis, electron probe micro analysis and transmission electron microscopy with the aim of better understanding the causes of the degradation. The chemical composition of the enamels diverges from the average chemical composition of window glass. Some of the compositions appear to be unstable, for example those with a high concentration of K 2O and a low content of CaO and PbO. In other cases, the deterioration of the paint layers was caused by the less than optimal vitrification of the enamel during the firing process. Recipes and chemical compositions indicate that glassmakers of the 16-17th century had full control over the color of the enamel glass paints they made. They mainly used three types of coloring agents, based on Co (dark blue), Mn (purple) and Cu (light-blue or green-blue) as coloring elements. Blue-purple enamel paints were obtained by mixing two different coloring agents. The coloring agent for red-purple enamel, introduced during the 19th century, was colloidal gold embedded in grains of lead glass.

Schalm, O.; Van der Linden, V.; Frederickx, P.; Luyten, S.; Van der Snickt, G.; Caen, J.; Schryvers, D.; Janssens, K.; Cornelis, E.; Van Dyck, D.; Schreiner, M.

2009-08-01

310

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

311

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

312

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

313

Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L.  

NASA Astrophysics Data System (ADS)

The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

Tahir, D.; Halide, H.; Wahab, A. W.; Kurniawan, D.

2014-09-01

314

Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L  

SciTech Connect

The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

Tahir, D., E-mail: dtahir@fmipa.unhas.ac.id; Halide, H., E-mail: dtahir@fmipa.unhas.ac.id; Kurniawan, D. [Department of Physics, Hasanuddin University, Makassar 90245 (Indonesia); Wahab, A. W. [Department of Chemistry, Hasanuddin University, Makassar 90245 (Indonesia)

2014-09-25

315

An investigation of interurban variations in the chemical composition and mutagenic activity of airborne particulate organic matter using an integrated chemical class/bioassay system  

NASA Astrophysics Data System (ADS)

Previous investigations in this laboratory have demonstrated that the mutagenic activities of extractable particulate organic matter (EOM) from cities which differ in their principal fuels and meteorology can vary significantly. To gain a better understanding of these interurban variations, an Integrated Chemical Class/Biological Screening System was developed and used for a more detailed examination of differences in the chemical composition and mutagenic activity of EOM. The screening system involved coupling in situ Ames mutagenicity determinations on high performance thin layer chromatography (HPTLC) plates with class specific chemical analyses on a second set of plates. The system was used to screen for mutagenic activity and selected chemical classes (including PAH, nitro-PAH, phenols, carboxylic acids, carbonyls, aza-arenes and alkylating agents) in EOM from the following sites: New York City; Elizabeth, N.J.; Mexico City; Beijing, China; Philadelphia, PA; and the Caldecott Tunnel (CA). The results of this study demonstrated mutagenic activity and chemical compositional differences in HPTLC subfractions of particulate organic matter from these cities and from the Caldecott Tunnel. The greatest interurban differences in chemical classes were observed for the phenols, carbonyl compounds and alkylating agents. Interurban variations in mutagenic activities were greatest for EOM subfractions of intermediate polarity. These differences are probably related to interurban differences in the fuels used, types of sources and atmospheric conditions. The relationships between these variables are not well understood at present.

Butler, J. P.; Kneip, T. J.; Daisey, J. M.

316

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

317

SiC whisker/Si3N4 composites by a chemical mixing process  

SciTech Connect

A chemical mixing process has been developed for making SiC whisker/Si3N4 composites. The process involves in situ synthesis of SiC whiskers in Si3N4 powder by partial carbothermal reduction of silicon nitride in an argon atmosphere. The effects of reaction conditions and starting raw materials on the formation of SiC whiskers were studied. It has been demonstrated that the morphologies of the in situ synthesized whiskers can be modified by varying carbon-source materials and reaction conditions, and the amount of SiC formed in the product can be adjusted by changing the starting Si3N4-to-C ratio. The chemically mixed composite materials were densified by hot pressing with Y2O3 and Al2O3 as sintering aids. 12 refs.

Wang, Hongyu; Fischman, G.S.

1991-10-01

318

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

319

Chemical composition and anti-proliferative properties of Bursera graveolens essential oil.  

PubMed

Bursera graveolens is a wild tree of commercial importance native to the Neotropics, which has been widely used in folk medicine. In the present study, the chemical composition and anti-proliferative properties of the essential oil from B. graveolens were assayed. The chemical composition of the essential oil, determined by GC-MS, was complex and dominated by limonene (26.5%). Bursera oil inhibited the growth of MCF-7 breast tumor cells as well as amastigotes of L. amazonensis, with IC50 values of 48.9 +/- 4.3 and 36.7 +/- 4.7 microg/mL, respectively. In addition, the cytotoxicity of the oil was 103.9 +/- 7.2 microg/mL against peritoneal macrophages from BALB/c mice. These results demonstrate that the essential oil from B. graveolens is a promissory antiproliferative product. PMID:23285824

Monzote, Lianet; Hill, Gabrielle M; Cuellar, Armando; Scull, Ramón; Setzer, William N

2012-11-01

320

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

321

[Characteristics of chemical composition of glass finds from the Qiemo tomb sites on the Silk Road].  

PubMed

Qiemo was an ancient country on the south branch of the Silk Road. The Zagunluke tomb site is located at the Qiemo County of the Xinjiang Uygur Autonomous Region. Glass beads and only colourless glass cup were excavated from the 3rd cultural layer of the tomb site M133 and M49, dated between the 1st AD-6th AD. LA-ICP-AES was applied to analyse chemical composition of these glass finds with the corning glass as reference. According to the result, characteristics of chemical composition are very similar to typical soda-lime glass, which indicates the glasses were imported productions from the west. These soda-lime glasses were divided into two groups in terms of flux source: natron glass and plant ash glass. This analytical research indicates the history of glass trade and communication between the East and the West on the Silk Road. PMID:23016362

Cheng, Qian; Guo, Jin-Long; Wang, Bo; Cui, Jian-Feng

2012-07-01

322

Chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oil  

PubMed Central

Background and Objectives The aim of this study was to evaluate the chemical composition and antimicrobial activity of Satureja hortensis and Trachyspermum copticum essential oils against different kinds of microorganisms in vitro. Material and Methods The antimicrobial activity was evaluated by micro broth dilution assay and the chemical composition of essential oils was analyzed by GC and GC/MS. Results Thymol, p-cymene, ?-terpinene and carvacrol were the main components of S. hortensis oil while thymol, ?-terpinene, and o-cymene were the major components of T. copticum oil. Two essential oils exhibited strong antimicrobial activity but the antimicrobial activity of T. copticum oil was higher than that of S. hortensis oil. Conclusion Thymol as a main component of oils plays an important role in antimicrobial activity. PMID:22530088

Mahboubi, M; Kazempour, N

2011-01-01

323

Chemical composition, phytotoxic and antifungal properties of Ruta chalepensis L. essential oils.  

PubMed

The chemical composition, and phytotoxic and antifungal activities of the essential oils isolated by using hydrodistillation from the aerial parts of Tunisian rue were evaluated. Significant variations were observed among harvest periods. The analysis of the chemical composition by gas chromatography/mass spectrometry showed that 2-undecanone (33.4-49.8%), 2-heptanol acetate (13.5-15.4%) and ?-pinene (9.8-11.9%) were the main components. The antifungal ability of rue essential oils was tested by using disc agar diffusion against ten plant pathogenic fungi. A high antifungal activity was observed for the essential oil isolated at flowering developmental phase. Furthermore, rue essential oils showed high level of herbicidal activity against several weeds. PMID:25553803

Bouabidi, Wafa; Hanana, Mohsen; Gargouri, Samia; Amri, Ismail; Fezzani, Tarek; Ksontini, Mustapha; Jamoussi, Bassem; Hamrouni, Lamia

2015-05-01

324

Chemical compositions of essential oils from Xyloselinum vietnamense and X. selinum leonidii.  

PubMed

The chemical compositions of essential oils obtained by hydrodistillation from leaves and stems of Xyloselinum vietnamense and X. leonidii, two new species belonging to the family Apiaceae, were analyzed by GC-MS. The major components in both species were sabinene, alpha- and beta-pinene, myrcene, beta-phellandrene, (Z)-beta-ocimene, and terpinen-4-ol. The monoterpene sabinene was most abundant in the leaves of X. vietnamense (75.0%). These compounds might be considered as chemotaxonomic markers of Xyloselinum species. In the DPPH radical scavenging assay, all four essential oils showed moderate activity, while the water extracts exhibited stronger effects. The strong DPPH scavenging activity of the water residues of X. vietnamens and X. leonidii might be due to their phenolic components. This paper is the first report on the chemical compositions and antioxidant activity of X. vietnamens and X. leonidii. PMID:23162914

Tran, Huy Thai; Nguyen, Sinh Khang; Nguyen, Thi Hien; Tran, Minh Hoi; Nguyen, Tien Dat

2012-10-01

325

Antioxidant properties, physico-chemical characteristics and proximate composition of five wild fruits of Manipur, India.  

PubMed

Antioxidant properties, physico-chemical characteristics and proximate composition of five wild fruits viz., Garcinia pedunculata, Garcinia xanthochymus, Docynia indica, Rhus semialata and Averrhoa carambola grown in Manipur, India were presented in the current study. The order of the antioxidant activity and reducing power of the fruit samples was found as R. semialata?>?D. indica?>?G. xanthochymus?>?A. carambola?>?G. pedunculata. Good correlation coefficient (R(2)?>?0.99) was found among the three methods applied to determine antioxidant activity. Total phenolic content was positively correlated (R(2)?=?0.960) with the antioxidant activity however, total flavonoid content was not positively correlated with the antioxidant activity. Physico-chemical and proximate composition of these fruits is documented for the first time. PMID:25694698

Sharma, Ph Baleshwor; Handique, Pratap Jyoti; Devi, Huidrom Sunitibala

2015-02-01

326

Protein isolates from chickpea ( Cicer arietinum L.): chemical composition, functional properties and protein characterization  

Microsoft Academic Search

Two types of protein isolates were prepared from ground chickpea seeds by alkaline extraction, with (Isolate-B) and without (Isolate-A) sodium sulphite, and acid precipitation of the proteins at the isoelectric point (pI 4.3). The percentage of protein recovered from chickpea flour in the preparation of Isolates-A and B were 65.9 and 62.1%, respectively. Chemical composition, main functional properties and protein

R Sánchez-Vioque; A Clemente; J Vioque; J Bautista; F Millán

1999-01-01

327

Chemical composition and quality characteristics of chevon from goats fed three different post-weaning diets  

Microsoft Academic Search

Thirty-six Boer×Spanish intact male goats (BW=18±0.8kg; age 4 months) were used to determine the effects of dietary treatments on the chemical composition and quality characteristics of goat meat (chevon). Animals were allotted to three treatment groups (n=12\\/treatment) with three pens for each treatment. Each pen of four goats was fed one of three dietary treatments for 90 d: (1) a

J. H. Lee; B. Kouakou; G. Kannan

2008-01-01

328

Differences in the chemical composition of dissolved organic matter from waste material of different sources  

Microsoft Academic Search

The chemical composition of waste-material-derived dissolved organic matter (DOM) was characterized by chemolytic analyses and 1H, 13C and 31P nuclear magnetic resonance (NMR) spectroscopy. Dissolved organic matter was extracted by water from an aerobic fermented urban waste compost, a sewage sludge and a pig slurry and then fractionated using the XAD-8 method. The amount of water-extractable dissolved organic carbon (DOC)

Giovanni Gigliotti; Klaus Kaiser; Georg Guggenberger; Ludwig Haumaier

2002-01-01

329

The chemical composition and antibacterial activity of the leaf extract of Salvia repens Burch. Ex Benth  

Microsoft Academic Search

The chemical composition of the essential oil of S. repens contain the following major constituents: 1 - camphor (0.4%) para-cymene (34.1%), sabinene (23.9%), 1-? ? ? ?-pinene (16.9%),, myrcene (3.9%), ? - terpinene (1.8%), trans- ? ? ? ?-Ocimene (1.3%), terpinene-4-ol (0.7%), nopol (0.4%), ? ? ? ?-terpinolene (15.89%), ? ? ? ? - caryophllene (0.6%). The antibacterial activity of

Buyisile Mayekiso; Micheal L. Magwa; Roger M. Coopoosamy

330

Relative toxicity of pyrolysis gases from materials - Effects of chemical composition and test conditions  

NASA Technical Reports Server (NTRS)

Relative toxicity test data on 270 materials are presented, based on test procedures developed at the University of San Francisco. The effects of chemical composition, using data on 13 types of synthetic polymers and eight types of fabrics, are discussed. Selected materials were evaluated using nine test conditions with the USF method, and using methods developed at the FAA Civil Aeromedical Institute, Douglas Aircraft Company and San Jose State University.

Hilado, C. J.; Cumming, H. J.

1978-01-01

331

Antimicrobial activity and chemical composition of endemic Centaurea cariensis subsp. niveo-tomentosa  

Microsoft Academic Search

The antimicrobial activity of the n-hexane, chloroform, ethyl acetate and ethyl alcohol extracts of the aerial parts of Centaurea cariensis subsp. niveo-tomentosa was evaluated against microorganisms, including multi-antibiotic resistant bacteria, using the paper disc diffusion method. The chemical composition of the chloroform extract of this plant was determined by gas chromatography and gas chromatography-mass spectrometry. The chloroform extract exhibited significant

Aysel Ugur; Nurdan Sarac; Ozgur Ceylan; M. Emin Duru

2010-01-01

332

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

333

Chemical composition, antibacterial and antifungal activities of the essential oil of Haplophyllum tuberculatum from Oman  

Microsoft Academic Search

The chemical composition of the essential oil of Haplophyllum tuberculatum (Forsskal) A. Juss (Rutaceae) was analyzed by gas chromatography–mass spectral (GC–MS) and 13C NMR spectroscopy. Thirty compounds, constituting about 99.7% of the total oil, were identified. The most abundant oil components are ?-phellandrene (23.3%), limonene (12.6%), (Z)-?-ocimene (12.3%), ?-caryophyllene (11.6%), myrcene (11.3%), and ?-phellandrene (10.9%). Ten microlitres (25mg) of pure

Suad Khamis S. Al-Burtamani; Majekodunmi O. Fatope; Ruchi G. Marwah; Anthony K. Onifade; Salim H. Al-Saidi

2005-01-01

334

Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging  

Microsoft Academic Search

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to\\u000a its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as\\u000a well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by

Notburga Gierlinger; Lanny Sapei; Oskar Paris

2008-01-01

335

Chemical vapor infiltration (CVI)—Part I: a new technique to achieve diamond composites  

Microsoft Academic Search

Diamond\\/metal or diamond\\/ceramics penetration structures have a high potential as, e.g. heat sinks in the microelectronic industry and for tribological applications. To learn more about the basic principles in fabricating these new composites, we infiltrated porous structures of silicon carbide with diamond by chemical vapor infiltration (CVI). As a result we get a 3D penetration structures of diamond and substrate.

A. Glaser; S. M. Rosiwal; B. Freels; R. F. Singer

2004-01-01

336

Modeling of an improved chemical vapor infiltration process for ceramic composites fabrication  

Microsoft Academic Search

A quasi-steady-state approach is applied to model the pressure-driven, temperature-gradient chemical vapor infiltration (improved CVI process) for ceramic matrix composites fabrication. The deposited matrix in this study is SiC which is converted from the thermal decomposition of methyltrichlorosilane gas under excess hydrogen. A three-dimensional unit cell is adopted to simulate the spatial arrangements of reinforcements in discontinuous fiber mats and

Nyan-Hwa Tai; Tsu-Wei Chou

1990-01-01

337

Response of lime seedling growth and chemical composition to salinity stress  

Microsoft Academic Search

Responses of lime growth and chemical composition to salinity stress were evaluated on six?month?old lime seedlings raised under six salt levels with electrical conductivities (EC) ranging from 0.56–20 d?Sm together with Soba natural saline soil with an intrinsic salinity of 7.2 d?Sm. Plantheight, number of leaves and branches, moisture content, and chlorophyll and nitrogen (N) contents were progressively reduced by

El Agib B. El Hag; Osman A. Sidahmed

1997-01-01

338

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

339

The chemical composition of hexane extract from bark of Juniperus brevifolia  

Microsoft Academic Search

The phytochemical analysis of the bark of Juniperus brevifolia was undertaken for the first time. The GC–MS analysis of the hexane extract from bark of “cedro-do-mato” (J. brevifolia) allowed to identify three rare compounds for the first time in Juniperus genus: 6,7-dehydroferrugin-12-methyl ether, 11-hydroxy-6,7-dehydroferruginol and 6,7-dehydrohinokiol. The results also showed that the chemical composition of the extract were essentially abietane-type

A. M. L. Seca; A. M. S. Silva

2008-01-01

340

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

341

Evolution of pH and chemical composition of pore solution in carbonated concrete  

Microsoft Academic Search

An investigation of carbonation in concrete, the pH and chemical composition change of the pore solution in concrete with different degrees of carbonation, was presented. The concrete samples were manufactured using ordinary portland cement and fly ash with dimension of 100mm diameter by 3mm in height, and six different mix proportions. The concrete samples were exposed to the environment (CO2

Qi Pu; Linhua Jiang; Jinxia Xu; Hongqiang Chu; Yi Xu; Yan Zhang

342

Chemical Composition and Isotopic Characteristics of the Carbonate Cements in Sandstone Reservoir Layer of Dongying Sinking  

Microsoft Academic Search

The chemical composition of the carbonate cements in reservoir sandstones was determined by the EPMA. The generation sequence is: calcite, dolomite, ferrous calcite, ankerite, and the latest are coarse-grained and fine-grained calcites which are veined. In the MnO-FeO-MgO triangular diagram, the samples fall clearly on the four areas. The carbon and oxygen isotope data on the carbonate cements show that

Chengdong Liu; Shoupeng Zhang; Ting Liu; Zhaobin Yan; Guolin Guo; Liang Liang

2011-01-01

343

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

344

Chemical composition and mass closure of particulate matter at six urban sites in Europe  

Microsoft Academic Search

The chemical composition of fine (PM2.5) and coarse (PM2.5?10) particulate matter was investigated in 7-week field campaigns of contrasting air pollution at six urban background sites in Europe. The campaigns were scheduled to include seasons of local public health concern due to high particulate concentrations or findings in previously conducted epidemiological studies. The sampling campaigns were carried out as follows:

Markus Sillanpää; Risto Hillamo; Sanna Saarikoski; Anna Frey; Arto Pennanen; Ulla Makkonen; Zoya Spolnik; René Van Grieken; Martin Braniš; Bert Brunekreef; Marie-Cecile Chalbot; Thomas Kuhlbusch; Jordi Sunyer; Veli-Matti Kerminen; Markku Kulmala; Raimo O. Salonen

2006-01-01

345

Chemical composition of teff (Eragrostis tef) compared with that of wheat, barley and grain sorghum  

Microsoft Academic Search

The chemical composition of teff, analyzed from uncontaminated seeds, revealed the superiority of the species in mineral nutritive\\u000a value. Teff’s exceedingly high iron and calcium content was confirmed. The high iron content of teff reported by the Ethiopia\\u000a Nutrition Survey must have been due to certain inherent factors of the species, not only a result of contamination. The magnitude\\u000a of

Melak H. Mengesha

1966-01-01

346

Low-biodegradable composite chemical wastewater treatment by biofilm configured sequencing batch reactor (SBBR)  

Microsoft Academic Search

Biofilm configured system with sequencing\\/periodic discontinuous batch mode operation was evaluated for the treatment of low-biodegradable composite chemical wastewater (low BOD\\/COD ratio ?0.3, high sulfate content: 1.75g\\/l) in aerobic metabolic function. Reactor was operated under anoxic–aerobic–anoxic microenvironment conditions with a total cycle period of 24h [fill: 15min; reaction: 23h (aeration along with recirculation); settle: 30min; decant: 15min] and the performance

S. Venkata Mohan; N. Chandrasekhara Rao; P. N. Sarma

2007-01-01

347

Chemical Composition of Abaca (Musa textilis) Leaf Fibers Used for Manufacturing of High Quality Paper Pulps  

Microsoft Academic Search

The chemical composition of leaf fibers of abaca (Musa textilis), which are commonly used for high- quality paper pulp production, was thoroughly studied. The results revealed that the lignin content was 13.2% of the total fiber. The analysis of abaca fibers by pyrolysis coupled to gas chromatography- mass spectrometry (Py-GC\\/MS) released predominantly compounds arising from lignin and p- hydroxycinnamic acids,

DEL RIÄO; ANA GUTIE Ä RREZ

348

Factors affecting the microbial and chemical composition of silage. IV. Effect of wilting on maize silage.  

PubMed

The effect of wilting on the microbial and chemical composition of ensiled maize plants was studied. Wilting stimulated high densities of lactic acid bacteria, with the decrease in counts of undesirable flora, i.e., yeasts, moulds, proteolytic and saccharolytic anaerobes, causing spoilage of silage. Moreover, wilting decreased the losses of dry matter, total acidity, and butyric acid content of silage. Accordingly, wilting proved to be a favourable treatment for the production of good quality silage from maize plants. PMID:38606

Mahmoud, S A; Abdel-Hafez, A; Zaki, M M; Saleh, E A

1979-01-01

349

Chemical composition and organoleptic evaluation of juice from steamed cashew apple blended with orange juice  

Microsoft Academic Search

Fully riped cashew apples (yellow variety) were steamed for 7 minutes prior to juice extraction. The extracted juice was blended\\u000a with various proportions of sweet orange juice. Chemical composition and organoleptic evaluation were carried out on both\\u000a the blended and unblended juices. The ascorbic acid content of unsteamed cashew apple juice was 287 mg\\/100 ml. Steaming of\\u000a the cashew apple

U. E. Inyang; U. J. Abah

1997-01-01

350

Chemical Weathering of Black Shales and Rare Earth Element Composition of Surface Waters and Groundwater  

NASA Astrophysics Data System (ADS)

Weathering processes dominate the dissolved and suspended loads of most of the world's major rivers. Among sedimentary rocks, black shales are particularly sensitive to chemical weathering. Therefore, shale systems are useful for investigating the partitioning of chemical elements during chemical weathering. Recent studies, such as those by Peucker-Ehrenbrink, Ravizza and others, link chemical weathering of black shales to changes in marine isotopic composition. Rare earth elements (REE) have a unique chemistry and are ideal for such tracer studies. We explored the effect of modern chemical weathering of black shales on the hydrochemistry of surface and groundwaters in the Mohawk Valley of New York State. This region provides an ideal site for the investigation of trace element remobilization during the chemical weathering of black shales. In this region, surface and groundwaters, in intimate contact with black shales and have high dissolved metal concentrations presumably due to water-rock interactions. The extent to which the dissolved REE composition of the surface and ground waters retains the rock signature is, in someway related to the length of time that the water remains in contact with the rock. We compared the REE compositions of surface and groundwaters in areas draining black shale to those of waters draining regions of dolostone-limestone to explore the extent of metal release due to chemical weathering. Shale normalized REE patterns for stream waters exhibit slight heavy REE enrichments and, at some locations, LREE depletion. REE patterns of the waters normalized to their respective sediments show some LREE depletion. However, waters associated with the Little Falls dolomite show fractionation predominantly enriched in the heavy REEs. Differences between the black shale sites, recorded as light REE depletion and/or middle REE enrichment, may be related to the discharge of the streams and the total dissolved solids. The dissolved REE chemistry of rivers draining the limestone-dolostone facies to the north and west of the black shale facies is dominated by the Ln-carbonate species. REE speciation in the black shale sites when compared to the dolomitic sites show interesting features. For example, the "dolomite" lake exhibits a significant amount of free metal species as well as lanthanide-fluoride complexation. Our preliminary results indicate that the surface and groundwaters discretely record metal release from black shales. These data lend further credence to the hypothesis that black shale weathering may significantly contribute to the ocean metal budget.

Hannigan, R. E.; Johannesson, K. H.

2001-05-01

351

Chemical composition of fog and cloud water at the Erzgebirge summit, Germany  

NASA Astrophysics Data System (ADS)

The Erzgebirge as part of the former "Black Triangle" was one of the most polluted forested areas in Central Europe. The local climate is characterized by above-average stable air stratification leading to an above-average amount of inversions with advection fog. Thus, "acid fog" was thought to play an important role in the acidic deposition and in the forest decline on both sides of the Erzgebirge ridge (800 - 900 m a.s.l.). The last data on chemical composition and deposition of fog and cloud water were reported from the 1990's. This work determined the current chemical composition of fog and cloud water from the region in respect to the 1999 Gothenburg protocol. Chemical composition data of fog samples are reported from two sites: (1) Zinnwald, 877 m a.s.l., eastern Erzgebirge, and (2) Fichtelberg, 1214 m a.s.l. The latter results are the first data on the chemical composition of cloud water from that site. Passive fog collectors were used, and only exposed when fog occurred. Two collectors at Zinnwald (one for ion analysis and one for trace elements) and one collector at Fichtelberg were used. Electrical conductivity, pH-value, and the concentration of major ions and trace metals (Ba, Pb, Zn, Al, Mn, Ti, V, Ni, Cu, Sr, Cd, Sb, As, Cr) were determined. TOC was analysed in selected samples. Fog frequency in the investigation period (10.2009 - 12.2009) was comparable to long-term observations. Modelled liquid water contents (LWC) were in the range of typical values for German low elevation mountains. Minimum pH values, 3.5 for Zinnwald and 3.7 for Fichtelberg, were still of phytotoxic relevance. The chemical composition of fog and cloud water differed considerably between the sites. Zinnwald still is a polluted site with high concentrations of sulphate, nitrate, ammonium and organic compounds, while Fichtelberg is much less influenced by air pollution. There, sodium and chloride dominated the composition. At Zinnwald, Al, Zn, Pb, and Cu showed the highest trace metal concentrations, while As, Ni, Cr, and Cd were also detected. Sulphate concentrations were lower than in the late 1990s, while nitrate concentrations were considerably higher than before. This is surprising in the light of decreasing NOx emissions in Saxony and needs further investigations.

Schüttauf, S.; Zimmermann, F.; Matschullat, J.

2010-07-01

352

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

353

Chemical composition of the essential oils of serbian wild-growing Artemisia absinthium and Artemisia vulgaris.  

PubMed

The chemical composition of the aerial and root essential oils, hydrodistilled from Artemisia absinthium L. and Artemisia vulgaris L. (wild-growing populations from Serbia), were studied by gas chromatography, gas chromatography-mass spectrometry, and 13C nuclear magnetic resonance. During the storage of plant material under controlled conditions, a significant decrease of essential oil yields (isolated directly after drying and after 1 year of storage) and significant differences in their chemical compositions were observed. A possible mechanism for the observed oil component interconversion has been discussed. The noticeable differences in the chemical composition of the oils isolated from roots and aerial parts of A. absinthium and A. vulgaris were also correlated with the diverging biosynthetic pathways of volatiles in the respective plant organs. The antimicrobial activities against the common human pathogens of all of the isolated oils were tested according to National Committee on Clinical Laboratory Standards. The oils showed a broad spectrum of antimicrobial activity against the tested strains. Therefore, these oils can be used as flavor and fragrance ingredients. PMID:16787028

Blagojevi?, Polina; Radulovi?, Niko; Pali?, Radosav; Stojanovi?, Gordana

2006-06-28

354

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

355

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

356

Chemical Changes  

NSDL National Science Digital Library

This is an excellent resource for teachers and students. It offers countless lab ideas for teaching chemical and physical changes and is geared for fifth through eighth grade. It also gives interactive web addresses for students and includes PowerPoint presentations on this topic.

can& #39; t tell- a science educator- not affiliated with any specific organization

2011-10-10

357

Chemical separations  

SciTech Connect

This volume collects papers presented at a conference on chemical separation. Topics include: field-flow fractionation, chromatography, electrophoresis, solvent extraction in metals recovery, extraction of uranium and plutonium from nitric acid, modeling of flow fields in oscillating droplets, inclusion, and membrane processes.

King, J.C.; Navratil, J.D.

1986-01-01

358

Chemical Wonders  

NSDL National Science Digital Library

Students are introduced to chemical engineering and learn about its many different applications. They are provided with a basic introduction to matter and its different properties and states. An associated hands-on activity gives students a chance to test their knowledge of the states of matter and how to make observations using their five senses: touch, smell, sound, sight and taste.

Integrated Teaching and Learning Program,

359

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

360

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.

361

Chemical Composition of the essential oils from Vietnamese Clausena indica and C. anisum-olens.  

PubMed

The chemical composition of Vietnamese oil samples of the aerial parts of Clausena indica (Dalz.) Oliver and C. anisum-olens (Blanco) Merryll have been investigated using a combination of chromatographic and spectroscopic techniques. C. indica essential oil contained mainly terpinolene (53.9 and 56.1%), and myristicin (17.9 and 7.3%), whereas the major components of C. anisun-olens essential were citronellal (22.8%), geranial (21.4%) and neral (16.8%). The compositions of the investigated samples have been compared with those of essential oils from various origins. PMID:25522554

Thaia, Tran Huy; Bazzali, Ophélie; Hoi, Tran Minh; Hien, Nguyen Thi; Hung, Nguyen Viet; Félix Tomi; Casanova, Joseph; Bighelli, Ange

2014-10-01

362

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

363

Chemical synthesis of poly(lactic-co-glycolic acid)\\/hydroxyapatite composites for orthopaedic applications  

Microsoft Academic Search

Hydroxyapatite-biodegradable polymer composites were synthesized by a colloidal non-aqueous chemical precipitation technique at room temperature. The starting materials used for synthesizing hydroxyapatite (HA, Ca10(PO4)6(OH)2) were Ca(NO3)2·4H2O and H3PO4, resulting in single phase HA while poly(d,l-lactic-co-glycolic acid) (PLGA) was used as the biodegradable polymer component. The composites were prepared containing 10, 20, and 30wt.% HA in the presence of the dissolved

Sarah E. Petricca; Kacey G. Marra; Prashant N. Kumta

2006-01-01

364

Properties and chemical oxidation polymerization of polyaniline\\/neutral red\\/TiO 2 composite electrodes  

Microsoft Academic Search

Polyaniline\\/neutral red\\/TiO2 composite electrode materials (PANI\\/PNR\\/TiO2) are prepared by chemical oxidation polymerization. Structural and morphological characterizations of PANI\\/PNR and PANI\\/PNR\\/TiO2 are carried out by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results reveal a uniform dispersion of TiO2 nanoparticles in the netlike structure of PANI\\/PNR structure. Electrochemical performance of the composite electrodes is studied by cyclic voltammetry,

Haili Xu; Qi Cao; Xianyou Wang; Wenju Li; Xiaoyun Li; Huayang Deng

2010-01-01

365

Effect of chemical composition and superheat on macrostructure of high Cr white iron castings  

SciTech Connect

White cast irons are frequently used in applications requiring high wear resistance. High Cr white cast irons have a composite microstructure composed of hard (Fe,Cr)7C3 carbides in a steel matrix. Previous research has indicated that the equiaxed region of these high Cr white iron castings is much more wear resistant under high stress abrasive conditions than the columnar region, when the carbides are oriented perpendicular to the wear surface. In the present study, the effect of both the chemical composition, particularly carbon content, and the pouring superheat of the melt on the macrostructure of high Cr white iron castings is investigated.

Dogan, Omer N.

2005-08-01

366

Comparison surface characteristics and chemical composition of conventional metallic and nickel-free brackets.  

PubMed

This study aims at comparing conventional and nickel-free metal bracket surface characteristics with elemental composition by scanning electron microscopy (SEM), using energy dispersive spectroscopy (EDS). The sample consisted of 40 lower incisor brackets divided into four groups: ABZ = conventional brackets, Kirium Abzil 3M® (n = 10); RL = conventional brackets, Roth Light Morelli® (n = 10); NF = nickel-free brackets, Nickel-Free Morelli® (n = 10); and RM = nickel-free brackets, Roth Max Morelli® (n = 10). Qualitative evaluation of the bracket surface was performed using SEM, whereby surface features were described and compared. The elemental composition was analyzed by EDS. According to surface analysis, groups ABZ and RL showed a homogeneous surface, with better finishing, whereas the surfaces in groups NF and RM were rougher. The chemical components with the highest percentage were Fe, Cr and C. Groups NF and MR showed no nickel in their composition. In conclusion, the bracket surface of the ABZ and RL groups was more homogeneous, with grooves and pores, whereas the surfaces in groups NF and RM showed numerous flaws, cracks, pores and grooves. The chemical composition analysis confirmed that the nickel-free brackets had no Ni in their composition, as confirmed by the manufacturer's specifications, and were therefore safe to use in patients with a medical history of allergy to this metal. PMID:25590508

Shintcovsk, Ricardo Lima; Knop, Luegya Amorim Henriques; Gandini, Luiz Gonzaga; Martins, Lidia Parsekian; Pires, Aline Segatto

2015-01-01

367

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

368

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

369

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

370

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

371

Chemical Composition and Antioxidant Activities of Three Polysaccharide Fractions from Pine Cones  

PubMed Central

The traditional method of gas chromatography-mass spectrometry for monosaccharide component analysis with pretreatment of acetylation is described with slight modifications and verified in detail in this paper. It was then successfully applied to the quantitative analysis of component monosaccharides in polysaccharides extracted from the pine cones. The results demonstrated that the three pine cone polysaccharides all consisted of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose in different molar ratios. According to the recovery experiment, the described method was proved accurate and practical for the analysis of pine cone polysaccharides, meeting the need in the field of chemical analysis of Pinus plants. Furthermore; the chemical characteristics, such as neutral sugar, uronic acids, amino acids, molecular weights, and antioxidant activities of the polysaccharides were investigated by chemical and instrumental methods. The results showed that the chemical compositions of the polysaccharides differed from each other, especially in the content of neutral sugar and uronic acid. In the antioxidant assays, the polysaccharide fractions exhibited effective scavenging activities on ABTS radical and hydroxyl radical, with their antioxidant capabilities decreasing in the order of PKP > PAP > PSP. Therefore, although the polysaccharide fractions had little effect on superoxide radical scavenging, they still have potential to be developed as natural antioxidant agents in functional foods or medicine. PMID:23203063

Xu, Ren-Bo; Yang, Xin; Wang, Jing; Zhao, Hai-Tian; Lu, Wei-Hong; Cui, Jie; Cheng, Cui-Lin; Zou, Pan; Huang, Wei-Wei; Wang, Pu; Li, Wen-Jing; Hu, Xing-Long

2012-01-01

372

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

373

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

374

Lab 2: Mineral Lab notes. Minerals are inorganic, solid, naturally occurring substances that have a characteristic chemical compositions,  

E-print Network

Lab 2: Mineral Lab notes. Minerals are inorganic, solid, naturally occurring substances that have composition is the chemical elements that make up any given mineral. For instance, the mineral quartz is silicon dioxide SiO2; the mineral galena is an ore of lead, and its chemical formula is PbS, a lead

Li, X. Rong

375

Chemical Reactions  

NSDL National Science Digital Library

We are going go over a general view of reactions to prepare us for our unit on Chemical Reactions! Have fun learning! WARNING: If you are caught looking at ANY other site, without permission, you will be sent to the ALC, and you will not participate in any other computer activities for the rest of the year. Get your worksheet and begin! Overview Take this quiz and have me come over and sign off on your worksheet when you have completed the quiz! Overview Quiz Next let's take a look at what effect the rate of a chemical reaction. Rates of Reactions Another quiz, another check off by me! Rates of Reactions Quiz Now how do we measure how fast a ...

Mrs. Hicken

2009-05-04

376

Chemical warfare  

PubMed Central

Leaf-cutting ants are well known for their highly complex social organization, which provides them with a strong defense against parasites invading their colonies. Besides this attribute, these insects have morphological, physiological and structural characteristics further reinforcing the defense of their colonies. With the discovery of symbiotic bacteria present on the integument of leaf-cutting ants, a new line of defense was proposed and considered to be specific for the control of a specialized fungal parasite of the ants’ fungus gardens (Escovopsis). However, recent studies have questioned the specificity of the integumental bacteria, as they were also found to inhibit a range of fungi, including entomopathogens. The microbiota associated with the leaf-cutting ant gardens has also been proposed as another level of chemical defense, protecting the garden from parasite invasion. Here we review the chemical defense weaponry deployed by leaf-cutting ants against parasites of their fungus gardens and of the ants themselves. PMID:23795235

Samuels, Richard Ian; Mattoso, Thalles Cardoso; Moreira, Denise D.O.

2013-01-01

377

Chemical composition of high proper-motion stars based on short-wavelength optical spectra  

NASA Astrophysics Data System (ADS)

The results of spectroscopic observations made with the NES echelle spectrograph of the 6-m BTA telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in the wavelength interval of 3550-5100 Å with a spectral resolution of R?50000 are used to determine the fundamental parameters and atmospheric abundances of more than 20 chemical elements including heavy s- and r-process elements from Sr to Dy for a total of 14 metal-poor G-K-type stars. The abundances of Mg, Al, Sr, and Ba were calculated with non-LTE line-formation effects accounted for. The inferred overabundance of europium with respect to iron agrees with the results obtained for the stars of similar metallicity. The chemical composition of the star BD+80°245 located far from the Galactic plane is typical of stars of the accreted halo: this star exhibits, in addition to the over-deficiency of ?-process elements, also the over-deficiency of the ?-process element Ba: [Ba/Fe]= -1.46. The kinematical parameters and chemical composition imply that the stars studied belong to different Galactic populations. The abundance of the long-living element Th relative to that of the r-process element Eu is determined for six stars using the synthetic-spectrum method.

Klochkova, V. G.; Mishenina, T. V.; Panchuk, V. E.; Korotin, S. A.; Marsakov, V. A.; Usenko, I. A.; Tsymbal, V. V.

2011-01-01

378

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

379

Propolis from northern California and Oregon: chemical composition, botanical origin, and content of allergens.  

PubMed

Propolis is a beehive product that bees manufacture by mixing their own wax with vegetable resins collected from different species of trees and bushes. The chemical composition of propolis is very variable because it depends on the flora locally available, and specimens from different geographical and climatic areas display unique properties. In this paper, the results of the chemical characterization of some propolis specimens collected in northern California and in Oregon are presented. Their chemical compositions show that all specimens contain resins from poplars of the Tacamahaca section (balsam poplars)--characteristic of the western part of the North American continent. Nevertheless, some of the specimens are of mixed origin because they also contain resins from poplars of the Aigeiros section (cottonwoods)--also present in this part of the world. Propolis causes allergies in sensitive human individuals, which are due to the presence of certain esters. The contents of known propolis allergenic esters--phenylethyl caffeate, 1,1-dimethylallyl caffeate, benzyl cinnamate, and benzyl salicylate--have been investigated in these specimens and found to depend on the botanical origin. PMID:24772818

Aliboni, Andrea

2014-01-01

380

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

381

Chemical composition and thermal behavior of five brands of thermoplasticized gutta-percha  

PubMed Central

Objective: The aim of this study was determine the chemical composition and thermal behavior of Thermafil (TH), Microseal Cone (MC), Microseal Microflow (MF), Obtura (OB) and Obtura Flow (OF). In addition, their thermal behavior in response to temperature variations was studied by differential scanning calorimetry (DSC) to determine the temperature at which gutta-percha switches from the beta to alpha form, and from the alpha to the amorphous phase. Materials and Methods: The organic and inorganic fractions were separated by dissolution in chloroform. Gutta-percha (GP) was precipitated with acetone. The inorganic fraction was analyzed via Elemental Microanalysis. Energy Dispersive X-ray Microanalysis and X-ray Diffraction were used to identify the chemical elements and compounds (BaSO4 and ZnO). Thermal analysis was conducted using DSC. Results: The organic and inorganic fractions ranged from 21.3% and 26.9% of weights, respectively. MC and MF showed the highest percentages of organic compounds (P = 0.0125). All specimens exhibited two crystalline transformations when heated from ambient temperature to 130°C. MC presented the highest percentage of GP. Conclusions: No correlation was observed between chemical composition and thermal behavior. Each of the products showed thermal behavior that is typical of beta-phase gutta-percha. PMID:24883027

Maniglia-Ferreira, Claudio; Gurgel-Filho, Eduardo Diogo; de Araújo Silva, João Batista; de Paula, Regina Célia Monteiro; de Andrade Feitosa, Judith Pessoa; de Sousa-Filho, Francisco José

2013-01-01

382

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

383

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

384

High-Resolution Spectroscopy of Extremely Metal-Poor Stars from SDSS/SEGUE: I. Atmospheric Parameters and Chemical Compositions  

E-print Network

Chemical compositions are determined based on high-resolution spectroscopy for 137 candidate extremely metal-poor (EMP) stars selected from the Sloan Digital Sky Survey (SDSS) and its first stellar extension, the Sloan ...

Aoki, Wako

385

Chemical composition of seminal and ovarian fluids of chinook salmon (Oncorhynchus tshawytscha) and their effects on sperm motility traits  

E-print Network

Chemical composition of seminal and ovarian fluids of chinook salmon (Oncorhynchus tshawytscha- ), osmolality, and pH of ovarian and seminal fluid of sexually mature chinook salmon (Oncorhynchus tshawytscha

Montgomerie, Bob

386

Chemical composition and mechanisms underlying the spasmolytic and bronchodilatory properties of the essential oil of Nepeta cataria L  

Microsoft Academic Search

Aim of the studyThe study was aimed to investigate the chemical composition and pharmacological basis for traditional use of essential oil of Nepeta cataria L. (Limiaceae) (Nc.Oil) in gastrointestinal and respiratory disorders.

Anwar H. Gilani; Abdul J. Shah; Amina Zubair; Sana Khalid; Jawad Kiani; Amir Ahmed; Munawwer Rasheed; Viqar U. Ahmad

2009-01-01

387

Time-resolved fluorescence spectroscopic study of crude petroleum oils: influence of chemical composition.  

PubMed

The fluorescence of crude petroleum oils is sensitive to changes in chemical composition and many different fluorescence methods have been used to characterize crude oils. The use of fluorescence lifetimes to quantitatively characterize oil composition has practical advantages over steady-state measurements, but there have been comparatively few studies in which the lifetime behavior is correlated with gross chemical compositional data. In this study, the fluorescence lifetimes for a series of 23 crude petroleum oils with American Petroleum Institute (API) gravities of between 10 and 50 were measured at several emission wavelengths (450-785 nm) using a 380 nm light emitting diode (LED) excitation source. It was found that the intensity average fluorescence lifetime (tau) at any emission wave-length does not correlate well with either API gravity or aromatic concentration. However, it was found that tau is strongly negatively correlated with both the polar and sulfur concentrations and positively correlated with the corrected alkane concentration. This indicates that the fluorescence behavior of crude petroleum oils is governed primarily by the concentration of quenching species. All the strong lifetime-concentration correlations are nonlinear and show a high degree of scatter, especially for medium to light oils with API gravities of between 25 and 40. The degree of scatter is greatest for oils where the concentrations (wt %) of the polar fraction is approximately 10 +/- 4%, the asphaltene component is approximately 1 +/- 0.5%, and sulfur is 0.5 +/- 0.4%. This large degree of scatter precludes the use of average fluorescence lifetime data obtained with 380 nm excitation for the accurate prediction of the common chemical compositional parameters of crude petroleum oils. PMID:15165340

Ryder, Alan G

2004-05-01

388

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

389

Chemical composition and biological activities of essential oil from Salvia sclarea plants regenerated in vitro.  

PubMed

The essential oils obtained by hydrodistillation of dried aerial parts of Salvia sclarea L. plants, regenerated in vitro and reproduced from seeds, were analyzed by GC and GC-MS. The oils from in vitro and in vivo plants were compared in respect to their chemical composition as well as antimicrobial and cytotoxic activities. The chemical profiles of both oils were very similar, although the yield of essential oil from in vitro plants was lower (0.1%, v/w) than the oil yield isolated from in vivo S. sclarea plants (0.2%, v/w). Both oils showed antimicrobial and cytotoxic activity. The oil from in vitro regenerated plants of S. sclarea exhibited stronger cytotoxic action against NALM-6 cell lines in comparison with the essential oil from in vivo plants. PMID:19384275

Ku?ma, Lukasz; Kalemba, Danuta; Rózalski, Marek; Rózalska, Barbara; Wieckowska-Szakiel, Marzena; Krajewska, Urszula; Wysoki?ska, Halina

2009-01-01

390

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

391

[Comparison of green coffee beans volatiles chemical composition of Hainan main area].  

PubMed

Chemical component of Hainan green coffee beans was analyzed with solid phase microextraction-gas chromatography-mass spectrometry, and the discrepancy between two green coffee beans was differentiated through the spectrum database retrieval and retention index of compound characterization. The experimental results show that: the chemical composition of Wanning coffee beans and Chengmai coffee beans is basically the same. The quantity of analyzed compound in Wanning area coffee is 91, and in Chengmai area coffee is 106, the quantity of the same compound is 66, and the percent of the same component is 75.52%. The same compounds accounted for 89.86% of the total content of Wanning area coffee, and accounted for 85.70% of the total content of Chengmai area coffee. PMID:23697152

Hu, Rong-Suo; Chu, Zhong; Gu, Feng-Lin; Lu, Min-Quan; Lu, Shao-Fang; Wu, Gui-Ping; Tan, Le-He

2013-02-01

392

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

393

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

394

Chemical composition and physical quality characteristics of Ghanaian cocoa beans as affected by pulp pre-conditioning and fermentation  

Microsoft Academic Search

Investigations were conducted to evaluate the effects of pod storage (as a means of pulp preconditioning) and fermentation\\u000a on the chemical composition and physical characteristics of Ghanaian cocoa beans. A 4?×?2 full factorial design with factors\\u000a as pod storage (0, 7, 14, 21 days) and cocoa treatment (fermented and unfermented) were conducted. Samples were analyzed for\\u000a their chemical composition (moisture, crude

Emmanuel Ohene Afoakwa; Jennifer Quao; Jemmy Takrama; Agnes Simpson Budu; Firibu Kwesi Saalia

395

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

SciTech Connect

This second progress report describes the status of the project one and one-half years after the start. The goal of the project is to develop the instrumentation to collect cloud condensation nuclei (CCN) in sufficient amounts to determine their chemical composition, and to survey the CCN composition in different climates through a series of field measurements. Our approach to CCN collection is to first form droplets on the nuclei under simulated cloud humidity conditions, which is the only known method of identifying CCN from the background aerosol. Under cloud chamber conditions, the droplets formed become larger than the surrounding aerosol, and can then be removed by inertial impaction. The residue of the evaporated droplets represents the sample to be chemically analyzed. Two size functions of CCN particles are collected by first forming droplets on the large particles are collected by first forming droplets on the large CCN in a haze chamber at 100% relative humidity, and then activating the remaining CCN at 1% supersaturation in a cloud chamber. The experimental apparatus is a serious flow arrangement consisting of an impactor to remove the large aerosol particles, a haze chamber to form droplets on the remaining larger CCN, another impactor to remove the haze droplets containing the larger CCN particles for chemical analysis, a continuous flow diffusion (CFD) cloud chamber to form droplets on the remaining smaller CCN, and a third impactor to remove the droplets for the small CCN sample. Progress is documented here on the development of each of the major components of the flow system. Chemical results are reported on tests to determine suitable wicking material for the different plates. Results of computer modeling of various impactor flows are discussed.

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

1992-02-01

396

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

397

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

398

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

399

The Chemical Nature of the Fiber/resin Interface in Composite Materials  

NASA Technical Reports Server (NTRS)

Carbon fiber/epoxy resin composites are considered. The nature of the fiber structure and the interaction that occurs at the interface between fiber and matrix are emphasized. Composite toughness can be improved by increased axial tensile and compressive strengths in the fibers. The structure of carbon fibers indicates that the fiber itself can fail transversely, and different transverse microstructures could provide better transverse strengths. The higher surface roughness of lower modulus and surface-treated carbon fibers provides better mechanical interlocking between the fiber and matrix. The chemical nature of the fiber surface was determined, and adsorption of species on this surface can be used to promote wetting and adhesion. Finally, the magnitude of the interfacial bond strength should be controlled such that a range of composites can be made with properties varying from relatively brittle and high interlaminar shear strength to tougher but lower interlaminar shear strength.

Diefendorf, R. J.

1984-01-01

400

Chemical composition of essential oils from the vegetative and reproductive structures of Copaifera langsdorffii Desf.  

PubMed

GC/FID and GC-MS analysis revealed germacrene D, bicyclogermacrene, ?-cadinol and cubenol as major compounds from aril. Germacrene D, bicyclogermacrene, trans-caryophyllene and ?-elemene are major compounds in fruits. Germacrene D, spathulenol, trans-caryophyllene and caryophyllene oxide are major compounds in leaves. Furthermore, multivariate analysis revealed distinct groups between the composition of essential oils from aril and fruit, when compared with terpene production found in leaves. Lipid composition found in arils could be protected by the presence of non-oxygenated sesquiterpenes, as germacrene D and bicyclogermacrene. Chemical profiles of essential oils from the fruits, arils and leaves of Copaifera langsdorffii Desf. revealed different compositions, which could be related to environmental pressures. Thereby, non-oxygenated sesquiterpenes can also work against herbivory, pathogens and predator's attack, emphasising the importance of further studies among terpenes, ecology interactions and plant physiology. PMID:25588080

Portella, Roberto de Oliveira; Facanali, Roselaine; Marques, Márcia Ortiz Mayo; Rolim de Almeida, Luiz Fernando

2015-05-01

401

Wet chemically grown composite thin film for room temperature LPG sensor  

NASA Astrophysics Data System (ADS)

We have synthesized thin film of zinc oxide-polyaniline (ZnO/PANI) composite using a simple wet chemical approach. As-synthesized ZnO/PANI composite thin film studied using different characterization techniques. The optical study reveals the penetration and interaction of PANI molecules with ZnO thin film. Prominent blue shift in UV-vis due to interaction between ZnO and PANI indicate presence of zinc oxide in polyaniline matrix. It is observed that ZnO thin film is not sensitive to LPG (liquefied petroleum gas) at room temperature. On the other hand ZnO/PANI composite thin film shows good response and recovery behaviors at room temperature.

Birajadar, Ravikiran; Desale, Dipalee; Shaikh, Shaheed; Mahajan, Sandip; Upadhye, Deepak; Ghule, Anil; Sharma, Ramphal

2014-04-01

402

On the chemical composition of Titan’s dry lakebed evaporites  

NASA Astrophysics Data System (ADS)

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, D.; Barnes, J. W.; Ferreira, A. G.

2013-11-01

403

Chemical composition of the essential oil from Croton kimosorum, an endemic species to Madagascar.  

PubMed

Croton kimosorum Leandri is an endemic species to Madagascar. The chemical composition of aerial parts, leaf and stem oils is reported for the first time. Analysis was carried out by combination of chromatographic (CC, GC), spectroscopic and spectrometric (MS, 13C NMR) techniques. In total, 76 compounds have been identified. Essential oil isolated from aerial parts contained mainly linalool (21.6%), sabinene (10.4%), 1,8-cineole (6.3%), beta-pinene (6.2%), (E)-beta-caryophyllene (5.9%), terpinen-4-ol (4.8%), geraniol (4,5%) and germacrene D (2.3%). In comparison with the first sample, the composition of leaf and stem oils varied slightly, while essential oil isolated by vapor distillation from a semi-industrial still exhibited similar composition. PMID:24660481

Rabehaja, Delphin J R; Ihandriharison, Harilala; Ramanoelina, Panja A R; Benja, Rakotonirina; Ratsimamanga-Urverg, Suzanne; Bighelli, Ange; Casanova, Joseph; Tomi, Félix

2014-01-01

404

Evaluating the influence of chemical weathering on the composition of the continental crust using lithium and its isotopes  

NASA Astrophysics Data System (ADS)

The continental crust has an "intermediate" bulk composition that is distinct from primary melts of peridotitic mantle (basalt or picrite). This mismatch between the "building blocks" and the "edifice" of the continental crust points to the operation of processes that preferentially remove mafic to ultramafic material from the continents. Such processes include lower crustal recycling (via density foundering or lower crustal subduction - e.g., relamination, Hacker et al., 2011, EPSL), generation of evolved melts via slab melting, and/or chemical weathering. Stable isotope systems document the influence of chemical weathering on the bulk crust composition: the oxygen isotope composition of the bulk crust is distinctly heavier than that of primary, mantle-derived melts (Simon and Lecuyer, 2005, G-cubed) and the Li isotopic composition of the bulk crust is distinctly lighter than that of mantle-derive melts (Teng et al., 2004, GCA; 2008, Chem. Geol.). Both signatures mark the imprint of chemical weathering on the bulk crust composition. Here, we use a simple mass balance model for lithium inputs and outputs from the continental crust to quantify the mass lost due to chemical weathering. We find that a minimum of 15%, a maximum of 60%, and a best estimate of ~40% of the original juvenile rock mass may have been lost via chemical weathering. The accumulated percentage of mass loss due to chemical weathering leads to an average global chemical weathering rate (CWR) of ~ 8×10^9 to 2×10^10 t/yr since 3.5 Ga, which is about an order of magnitude higher than the minimum estimates based on modern rivers (Gaillardet et al., 1999, Chem. Geol.). While we cannot constrain the exact portion of crustal mass loss via chemical weathering, given the uncertainties of the calculation, we can demonstrate that the weathering flux is non-zero. Therefore, chemical weathering must play a role in the evolution of the composition and mass of the continental crust.

Rudnick, R. L.; Liu, X.

2011-12-01

405

Properties of thermo-chemically surface treated carbon fibers and of their epoxy and vinyl ester composites  

SciTech Connect

High strength carbon fibers were surface treated by a continuous gas phase thermo-chemical surface treatment. The surface and the mechanical properties of the fibers were investigated before and after treatment and compared to the properties obtained with a conventional industrial electro-chemical surface treatment. An increase of the oxygen atomic content from 3 % to 20 % with a preferential generation of carboxylic acid functionalities and hydroxyl groups was highlighted after the thermo-chemical surface treatment, compared to an oxygen atomic content of 7 % and a wide variety of oxygen moieties with the electro-chemical surface treatment. The tensile strength of the fibers increased slightly after the thermo-chemical surface treatment and remained the same after the electro-chemical surface treatment. Short beam shear and 90 flexural tests of composites revealed that the improvement of interfacial adhesion with a vinyl ester matrix was limited, revealing that oxidation of the carbon fiber surface alone cannot tremendously improve the mechanical properties of carbon fiber-vinyl ester composites. Atomic force microscopy showed that the creation of roughness with both surface treatments at a nanometric scale. Although the surface is slightly rougher after the electro-chemical surface treatment and is expected to lead to higher adhesion due to mechanical interlocking between the fiber surface and the matrix, the effect of covalent bonding coming from the high concentration of chemical groups on the surface results in higher adhesion strength, as obtained with the thermo-chemical surface treatment.

Vautard, Frederic [ORNL; Ozcan, Soydan [ORNL; Meyer III, Harry M [ORNL

2012-01-01

406

Estimation of aerosol water and chemical composition from AERONET at Cabauw, the Netherlands  

NASA Astrophysics Data System (ADS)

Remote sensing of aerosols provides important information on the atmospheric aerosol abundance. However, due to the hygroscopic nature of aerosol particles observed aerosol optical properties are influenced by atmospheric humidity, and the measurements do not unambiguously characterize the aerosol dry mass and composition which complicates the comparison with aerosol models. In this study we derive aerosol water and chemical composition by a modeling approach that combines individual measurements of remotely sensed aerosol properties (e.g. optical thickness, single scattering albedo, refractive index and size distribution) from an AERONET (Aerosol Robotic Network) sun-photometer with radiosonde measurements of relative humidity. The model simulates water uptake by aerosols based on the chemical composition and size distribution. A minimization method is used to calculate aerosol composition and concentration, which are then compared to in situ measurements from the Intensive Measurement Campaign At the Cabauw Tower (IMPACT, May 2008, the Netherlands). Computed concentrations show reasonable agreement with surface observations and follow the day-to-day variability in observations. Total dry mass (33 ± 12 ?g m-3) and black carbon concentrations (0.7 ± 0.3 ?g m-3) are generally accurately computed. The uncertainty in the AERONET (real) refractive index (0.025-0.05) introduces larger uncertainty in the modeled aerosol composition (e.g. sulfates, ammonium nitrate or organic matter) and leads to an uncertainty of 0.1-0.25 in aerosol water volume fraction. Water volume fraction is highly variable depending on composition, up to >0.5 at 70-80% and <0.1 at 40% relative humidity.

van Beelen, A. J.; Roelofs, G. J. H.; Hasekamp, O. P.; Henzing, J. S.; Röckmann, T.

2013-06-01

407

Effect of pedoclimatic conditions on the chemical composition of the Sigoise olive cultivar.  

PubMed

The present work focused on the quality and the chemical composition of monovarietal virgin olive oil from the Sigoise variety grown in two different locations in Tunisia, viz., a sub-humid zone (Béjaoua, Tunis) and an arid zone (Boughrara, Sfax). In addition to the quality characteristics (acidity, peroxide value, and the spectrophotometric indices K232 and K270) and the chemical composition (content of fatty acids, antioxidants, and volatile compounds) of the oil, the fruit characteristics of the olives were studied. Except for the content of the majority of the fatty acids, there were significant differences observed in the oil composition of olives that were cultivated in different locations. The content of total phenols and lipoxygenase (LOX) oxidation products was higher for olives grown at the higher altitude, whereas that of alpha-tocopherol, carotenes, and chlorophylls was higher for olives from the Boughrara region (lower altitude). Moreover, olives produced at the higher altitude showed a higher ripeness index and oil content than those cultivated at the lower altitude. PMID:20397230

Dabbou, Samia; Sifi, Samira; Rjiba, Imed; Esposto, Sonia; Taticchi, Agnese; Servili, Maurizio; Montedoro, Gian Francesco; Hammami, Mohamed

2010-04-01

408

Estimation of aerosol water and chemical composition from POLDER/PARASOL satellite retrievals of aerosol properties.  

NASA Astrophysics Data System (ADS)

Remote sensing of aerosols provides important information on the atmospheric aerosol abundance. Due to the hygroscopic nature of aerosol particles, their optical properties reflect not only the dry aerosol properties but are also influenced by atmospheric humidity. Remotely sensed aerosol optical properties are used to validate aerosol-climate models, but a more consistent validation requires knowledge of the actual aerosol dry chemical composition. We present results from a model that estimates the dry aerosol chemical composition and aerosol water, using remotely sensed aerosol properties from POLDER/PARASOL (e.g. optical thickness, single scattering albedo, refractive index and size distribution) and ECMWF relative humidity as input. The model applies a minimization technique to derive column-integrated quantities of sulfate, ammonium nitrate, sea salt, organic matter, black carbon and dust, for the aerosol fine and coarse modes. First, we compare POLDER data with data from AERONET to assess the accuracy and consistency of the input data, and discuss the influence of uncertainties in optical parameters (especially the refractive index) on the model results. Then, the model is applied to POLDER measurements at several near-oceanic sites. The results are used to investigate the monthly and seasonal variability of aerosol abundance and composition at these sites.

van Beelen, Arjan; Roelofs, Geert-Jan; Hasekamp, Otto; Röckmann, Thomas

2014-05-01

409

Mapping the nebular condensates and the chemical composition of the terrestrial planets  

NASA Astrophysics Data System (ADS)

We demonstrate that the condensation theory of planet formation yields solids of suitable compositions in the solar nebula that accrete to form the terrestrial planetary bodies. The mineral chemistry of the condensed objects provides definite criteria to establish the pressure and temperature of their formation. The solids condensing at a high nebular pressure of 0.01 to 0.001 bar and temperature of ?1530 K had the best chemical composition and density to form Mercury (64 wt% iron and 36 wt% oxides, density ?5.32 g cm). Solids that condensed around a pressure of 0.0001 bar or less and a temperature of ?700 K formed Earth and Venus (31 wt% iron, Ni and S and 69 wt% oxides, density ?4 g cm), and Mars (33.6 wt% Fe and S and 66.4 wt% oxides, density ?3.7 g cm). Iron sulfide provided S (3 wt%) for the core. Hydrous minerals forming in the lower temperature region provided water to the mantle. These results are highly significant because we have used only the chemical composition of the solar nebula, thermochemistry and astrophysical data on densities of the planets.

Saxena, Surendra K.; Hrubiak, Rostislav

2014-05-01

410

Antimicrobial Activity and Chemical Composition of Essential Oil From the Seeds of Artemisia aucheri Boiss  

PubMed Central

Background Artemisia aerial parts are well known for antimicrobial activities including anti malaria. Objectives This study was carried out to evaluate the antimicrobial activity and chemical composition of essential oil from the seeds of Artemisia aucheri Boiss (Asteraceae). Materials and Methods Essential oil was extracted from the powdered seeds of Artemisia aucheri by hydrodistillation. Antimicrobial activity against five bacterial species was tested using the disc diffusion method, and the chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Results The essential oil of Artemisia aucheri seed showed activity against Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes. The essential oil constituents identified by GC-MS were as follows: decane, ?-cymene, 1,8-cineole, linalool, ?-mentha-8-ol, triene, borneol, lavandulol, bornyl acetate, chrysanthenyl acetate, dehydro aromadenderene, and caryophyllene oxide. Most of these compounds are also found in the aerial parts of Artemisia aucheri. Conclusions Variation in the compositions of essential oils from Artemisia aucheri, and thus variation in the antimicrobial activity of these oils, may be due to the plant parts used for essential oil prepration. PMID:24624145

Asghari, Gholamreza; Jalali, Mohamad; Sadoughi, Ehsan

2012-01-01

411

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

412

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.

413

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

414

Biomass Production and Chemical Composition of Moringa oleifera under Different Management Regimes in Nicaragua  

Microsoft Academic Search

The effects of different planting densities (250,000, 500,000 and 750,000 plants ha?1) and cutting frequencies (45, 60 and 75 days) on the biomass production and chemical composition of Moringa oleifera was studied in a completely randomised split plot design with four blocks, in Managua, Nicaragua, located geographically\\u000a at 1208?15?? N and 8609?36?? E. The 75 day cutting frequency produced the highest fresh matter yield, 100.7 and

Nadir Reyes Sánchez; Stig Ledin; Inger Ledin

2006-01-01

415

Biological activity and chemical composition of the essential oil from Jamaican Hyptis verticillata Jacq.  

PubMed

The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Hyptis verticillata Jacq. was elucidated by a combination of GC and GC-MS analyses. The oil was dominated by the sesquiterpenoids cadina-4,10(15)-dien-3-one (15.1%) (1) and aromadendr-1(10)-en-9-one (squamulosone) (30.7%) (2). The oil exhibited chemosterilant activities against the cattle tick, Boophilus microplus Canest., and toxic action against adult Cylas formicarius elegantulus Summer, the most destructive pest of sweet potato (Ipomoea species). PMID:15941314

Facey, Petrea C; Porter, Roy B R; Reese, Paul B; Williams, Lawrence A D

2005-06-15

416

Chemical composition and antioxidant activities of Jeddah corniche algae, Saudi Arabia.  

PubMed

The increased use of natural product in the pharmaceutical industry has led to an increase in demand for screening for bioactive compounds in marine algae. An important economic algae, through chemical composition analysis and their antioxidant activities were investigated in this study. Chemical composition analysis of three algal samples from the Chlorophyta Ulva lactuca (U), Phaeophyta Sargassum crassifolia (S) and Rhodophyta Digenea simplex (D) was tested. Main components were sugars (57.40-185.13 mg/g dry weight), uronic acids (29.3-45.26 mg/g dry weight), sulfate (94.7-181.2 mg/g dry weight), amino acids (7.6-16.7 mg/g dry weight) and small amounts of betaines (2.38-8.47 mg/g dry weight). Hydrolyzed chemical composition analysis fractions of algal extract was shown a great proportion of sugars plus sulfate (as polysaccharide composed) ranges between 332 and 538.2 mg/g dry weight with trace amounts of uronic acids (?9%). All three algal extract showed antioxidant activities on lipoxygenase, DPPH and on Ames test. Two of aqueous extracts (U and D) inhibited lipoxygenase activity by less than 50%, where as the methanolic extract (S) caused 76% inhibition of the control. In all cases, the methanolic extract were more inhibitory than the aqueous extract. The (S) showed the highest antioxidant activity with DPPH (69%) in aqueous extract and in methanol extract with Ames test (85%). Both U and D showed antioxidant activity with DPPH in hexane by less of 25% where as in both aqueous and methanolic extracts by less than 50% of the control. Aqueous and methanolic extracts of U and D showed high inhibition by Ames test which caused 70% and 75% respectively. IR spectra of algal extracts (U; D and S) range from 1450 to 750 cm(-1) were very similar absorption band at 1430, 1370, 1250, 1130, 1110, 1050 and 1020 cm(-1). Absorption bands were due to uronic acids, glucosides and sulfate. The presence of sulfated polysaccharide material in the fractions UF2, DF2 and SF2 were found as cell wall storage of marine algae, confirmed by (13)C NMR spectroscopy. It is concluded that the algal species probably have a different components and can be used in the activities of antioxidant enzymes as reduced the risks of enzymes. But the correlation between the chemical composition and antioxidant activities of algal extracts needs further investigation. PMID:23961039

Al-Amoudi, Omar A; Mutawie, Hawazin H; Patel, Asmita V; Blunden, Gerald

2009-07-01

417

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

418

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

419

Chemical composition and biological activity of ripe pumpkin fruits (Cucurbita pepo L.) cultivated in Egyptian habitats.  

PubMed

The chemical composition and biological activity of three parts (rind, flesh and seeds) of pumpkin fruits (Cucurbita pepo L.) cultivated in Egypt were studied. Chemical analysis of fibre, protein, ?-carotene, carbohydrates, minerals and fatty acids present in the rind, flesh, seeds and defatted seeds meal was conducted. Chemical, GC-MS and biological assays of organic extracts of the main fruit parts, rind and flesh established their unique constituents. Chromatographic purification of the extracts afforded triglyceride fatty acid mixture (1), tetrahydro-thiophene (2), linoleic acid (3), calotropoleanly ester (4), cholesterol (5) and 13(18)-oleanen-3-ol (6). GC-MS analysis of the extract's unpolar fraction revealed the existence of dodecane and tetradecane. Structures of the isolated compounds (1-6) were confirmed by NMR and EI-MS spectrometry. Antimicrobial, antiviral and antitumour activities of the fruit parts were discussed. The promising combined extract of rind and flesh was biologically studied for microbial and cytotoxic activities in comparison with the whole isolated components. PMID:20603772

Badr, Sherif E A; Shaaban, Mohamed; Elkholy, Yehya M; Helal, Maher H; Hamza, Akila S; Masoud, Mohamed S; El Safty, Mounir M

2011-09-01

420

Influence of origin and extraction method on argan oil physico-chemical characteristics and composition.  

PubMed

Twenty one samples of argan oil of different geographical origin (Tidzi, Tamanar, Benaiznassen, Ait mzal, Ait Baha, Ighrem, Aoulouz) and/or prepared following a different process (traditional, mechanical, or industrial) were collected and their physico-chemical properties analyzed. Sample acidity was found between 0.14 and 1.40%, unsaponifiable matter between 0.34 and 0.79%, saponification value between 180.0 and 199.6, highest peroxide index was 5.72 meq/kg, refractive index (20 degrees C) between 1.4644 and 1.4705, and UV absorption at 270 nm between 0.228 and 0.605. This study, carried out on randomly selected samples, clearly demonstrates that press extraction does not alter either the chemical composition of argan oil or its physico-chemical characteristics. It also demonstrates that press extraction respects the critical factors reported for traditionally prepared oils and necessary to obtain a beneficial effect on human health (a specific fatty acid balance and high tocopherol and sterol levels). In addition, this study should be useful for the establishment of a national quality standard. PMID:15769139

Hilali, Miloudi; Charrouf, Zoubida; Soulhi, Abd El Aziz; Hachimi, Larbi; Guillaume, Dominique

2005-03-23

421

The impact of infield biomass burning on PM levels and its chemical composition.  

PubMed

In the South of Italy, it is common for farmers to burn pruning waste from olive trees in spring. In order to evaluate the impact of the biomass burning source on the physical and chemical characteristics of the particulate matter (PM) emitted by these fires, a PM monitoring campaign was carried out in an olive grove. Daily PM10 samples were collected for 1 week, when there were no open fires, and when biomass was being burned, and at two different distances from the fires. Moreover, an optical particle counter and a polycyclic aromatic hydrocarbon (PAH) analyzer were used to measure the high time-resolved dimensional distribution of particles emitted and total PAHs concentrations, respectively. Chemical analysis of PM10 samples identified organic and inorganic components such as PAHs, ions, elements, and carbonaceous fractions (OC, EC). Analysis of the collected data showed the usefulness of organic and inorganic tracer species and of PAH diagnostic ratios for interpreting the impact of biomass fires on PM levels and on its chemical composition. Finally, high time-resolved monitoring of particle numbers and PAH concentrations was performed before, during, and after biomass burning, and these concentrations were seen to be very dependent on factors such as weather conditions, combustion efficiency, and temperature (smoldering versus flaming conditions), and moisture content of the wood burned. PMID:24310905

Dambruoso, P; de Gennaro, G; Di Gilio, A; Palmisani, J; Tutino, M

2014-12-01

422

Microstructure and mechanical properties of three-dimensional carbon\\/silicon carbide composites fabricated by chemical vapor infiltration  

Microsoft Academic Search

Three-dimensional carbon\\/silicon carbide composites were fabricated by chemical vapor infiltration, and the microstructure and mechanical properties were investigated. For the composites (CSiC) with no pyrolytic carbon interfacial layer, the mechanical properties (flexural strength, flexural elastic modulus, shear strength and fracture toughness) are increased with density of the composites. High density (p = 2.1 g cm?3) CSiC composites exhibit high fracture

Yongdong Xu; Litong Zhang; Laifei Cheng; Dantao Yan

1998-01-01

423

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

424

The chemical composition and nitrogen distribution of Chinese yak (Maiwa) milk.  

PubMed

The paper surveyed the chemical composition and nitrogen distribution of Maiwa yak milk, and compared the results with reference composition of cow milk. Compared to cow milk, yak milk was richer in protein (especially whey protein), essential amino acids, fat, lactose and minerals (except phosphorus). The contents of some nutrients (total protein, lactose, essential amino acids and casein) were higher in the warm season than in the cold season. Higher ratios of total essential amino acids/total amino acids (TEAA/TAA) and total essential amino acids/total non essential amino acids (TEAA/TNEAA) were found in the yak milk from the warm season. However its annual average ratio of EAA/TAA and that of EAA/NEAA were similar to those of cow milk. Yak milk was rich in calcium and iron (p < 0.05), and thus may serve as a nutritional ingredient with a potential application in industrial processing. PMID:21954332

Li, Haimei; Ma, Ying; Li, Qiming; Wang, Jiaqi; Cheng, Jinju; Xue, Jun; Shi, John

2011-01-01

425

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

426

Chemical composition and biological activity of the essential oil from Jamaican Cleome serrata.  

PubMed

The chemical composition of the essential oil obtained from the aerial parts of Cleome serrata by hydrodistillation was analyzed by employing GC-FID, GC-MS and RI. Fourteen compounds comprising 90.4% of the total oil composition were characterized. The main components identified were (Z)-phytol (53.0%) and di(2-ethylhexyl)-phthalate (DEHP) (14.7%). The oil was evaluated for its in vitro antimicrobial activities against nine pathogenic microorganisms using the filter paper disc diffusion method. Moderate antimicrobial activity was observed against five of the pathogens assayed. In addition, the essential oil was tested against the sweet potato weevil, Cylas formicarius elegantulus. Strong knockdown insecticidal activity was observed. PMID:23074917

McNeil, Megil J; Porter, Roy B R; Williams, Lawrence A D

2012-09-01

427

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

428

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

429

Chemical Compositions and Antimicrobial Activities of Ocimum sanctum L. Essential Oils at Different Harvest Stages  

PubMed Central

Background: Essential Oils (EOs) possess antibacterial properties and represent a natural source to treat infections and prevent food spoilage. Their chemical composition might be affected by the environmental condition and the developmental growth stages of the plant. Objectives: The current study aimed to determine the variations in chemical compositions and antimicrobial activities of the EOs of Ocimum sanctum L. at different stages of harvesting. Materials and Methods: The oils constituents were analyzed by gas chromatography/mass spectrometry (GC/MS). The effects of three different harvest stages of O. sanctum EOs against most common causes of food-borne were evaluated by broth micro-dilution method as recommended by the Clinical and Laboratory Standards Institute (CLSI). Results: The analysis of the EOs indicated that eugenol was the major compound of the EOs at all developmental stages which reached its maximum level at the second stage. The results showed that the tested EOs exhibited antimicrobial activities against all of the examined pathogens at concentrations of 0.125-32 µL/mL, except Pseudomonas aeruginosa which was only inhibited by high concentrations of the floral budding and full flowering EOs. EO distilled from the second developmental growth stage (floral budding) of O. sanctum exhibited the strongest antibacterial activities against the food borne bacteria. Conclusions: Considering the wide range of antimicrobial activities of the examined EOs, they might have the potential to be used to manage infectious diseases or extend the shelf life of food products.

Saharkhiz, Mohammad Jamal; Kamyab, Amir Alam; Kazerani, Narges Khatoon; Zomorodian, Kamiar; Pakshir, Keyvan; Rahimi, Mohammad Javad

2014-01-01

430

Growth, chemical composition and soil properties of Tipuana speciosa (Benth.) Kuntze seedlings irrigated with sewage effluent  

NASA Astrophysics Data System (ADS)

This study was carried out at a greenhouse of Sabahia Horticulture Research Station, Alexandria, Egypt, to study the effect of sewage effluent on the growth and chemical composition of Tipuana speciosa (Benth.) Kuntze seedlings as well as on soil properties for three stages. The irrigation treatments were primary-treated wastewater and secondary-treated wastewater, in addition to tap water as control. Therefore, the treated wastewater was taken from oxidation ponds of New Borg El-Arab City. Results of these study revealed that the primary effluent treatment explored the highest significant values for vegetative growth and biomass, compared to the other treatments. In addition, the higher significant concentration and uptake of chemical composition in different plant parts were obtained from the primary effluent treatment during the three stages of irrigation. It was found that the concentration of heavy metals in either plant or soil was below as compared to the world-recommended levels. These findings suggested that the use of sewage effluent in irrigating T. speciosa seedlings grown in calcareous soil was beneficial for the improvement of soil properties and production of timber trees, and also important for the safe manner of disposal of wastewater.

Ali, Hayssam M.; Khamis, Mohamed H.; Hassan, Fatma A.

2012-06-01

431

Changes in chemical composition and antioxidative properties of rye ginger cakes during their shelf-life.  

PubMed

Changes in chemical composition and antioxidative properties of rye ginger cakes during their shelf-life were investigated in this study. In particular, the changes in antioxidants content, antioxidative and reducing capacity, and Maillard reaction development in rye ginger cakes after long-term storage were addressed. Ginger cakes produced according to the traditional and current recipe were stored for 5 years at room temperature in a dark place. The total phenolic compounds (TPC), inositol hexaphosphate (IP6), reduced (GSH) and oxidised glutathione (GSSG) contents, antioxidant and reducing capacity and Maillard reaction products (MRPs) were determined in ginger cakes after storage and then compared to those measured after baking. After long-term storage a decrease in TPC and IP6 contents in cakes was noted. In contrast, an increase in antioxidative and reducing capacity of stored cakes was observed. Long-term storage induced formation of furosine, advanced and final Maillard reaction products and caused changes in both reduced and oxidised forms of glutathione. After long-term storage the modest changes in furosine, FAST index and browning in ginger cake formulated with dark rye flour may suggest that this product is the healthiest among others. Therefore, traditional rye ginger cakes can be considered as an example of a healthy food that is also relatively stable during long term storage as noted by the small chemical changes observed in its composition. PMID:22980898

Zieli?ski, Henryk; del Castillo, Maria Dolores; Przygodzka, Ma?gorzata; Ciesarova, Zuzana; Kukurova, Kristina; Zieli?ska, Danuta

2012-12-15

432

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, William C.

1977-01-01

433

Chemical composition and Zn bioavailability of the soil solution extracted from Zn amended variable charge soils.  

PubMed

A study on variable charge soils (volcanic Italian and podzolic Scottish soils) was performed to investigate the influence of soil properties on the chemical composition of soil solution. Zinc speciation, bioavailability and toxicity in the soil solution were examined. The soils were spiked with increasing amounts of Zn (0, 100, 200, 400 and 1000 mg/kg) and the soil solutions were extracted using rhizon soil moisture samplers. The pH, total organic carbon (TOC), base cations, anions, total Zn and free Zn2+ in soil solution were analysed. A rapid bioassay with the luminescent bacterium Escherichia coli HB101 pUCD607 was performed to assess Zn toxicity. The influence of soil type and Zn treatments on the chemical composition of soil solution and on Zn toxicity was considered and discussed. Different trends of total and free Zn concentrations, base cations desorption and luminescence of E. coli HB101 pUCD607 were observed. The soil solution extracted from the volcanic soils had very low total and free Zn concentrations and showed specific Zn2+/Ca2+ exchange. The soil solution from the podzolic soil had much higher total and free Zn concentrations and showed no evidence of specific Zn2+/Ca2+ exchange. In comparison with the subalkaline volcanic soils, the acidic podzol showed enhanced levels of toxic free Zn2+ and consequently stronger effects on E. coli viability. PMID:21174971

Zampella, Mariavittoria; Adamo, Paola

2010-01-01

434

Chemical composition and antibacterial activity of Indian seagrasses against urinary tract pathogens.  

PubMed

Seagrasses have a long history of being used for a variety of remedial purposes, such as the fever, skin diseases, muscle pains, wounds and stomach problems. Hence it is essential to study their bioactive metabolites and medicinal properties when considering their food applications. The chemical composition of six seagrasses were determined and evaluated for their potential to urinary tract infection bacteria (UTI). The chemical composition determined by GC-MS yielded 24 compounds. For the first time 4H-Pyran-4-one-2,3-dihydro-3,5-dihydroxy-6-methyl- (6.68%), d-allose (3.67%) and 5-Caranol, trans,trans-(+)- (2.14%) were identified from Halodule pinifolia. d-Allose is a aldo-hexose (sugar) used as a potential inhibitor of glycosidases and low-calorie carbohydrate sweeteners. Among the six seagrasses tested, H. pinifolia and Cymodocea rotundata exhibited predominant growth inhibitory activity against all the UTI bacteria. This study shows the presence of various biological metabolites in tested seagrasses that can be used effectively in food and pharmacological industries. PMID:22980830

Ragupathi Raja Kannan, Rengasamy; Arumugam, Radjassegarin; Anantharaman, Perumal

2012-12-15

435

Dissolution of cerium(IV)-lanthanide(III) oxides: Comparative effect of chemical composition, temperature, and acidity  

SciTech Connect

The dissolution of Ce{sub 1-x}Ln{sub x}O{sub 2-x/2} solid solutions was undertaken in various acid media in order to evaluate the effects of several physicochemical parameters such as chemical composition, temperature, and acidity on the reaction kinetics. The normalized dissolution rates (R{sub L,0}) were found to be strongly modified by the trivalent lanthanide incorporation rate, due to the presence of oxygen vacancies decreasing the samples cohesion. Conversely, the nature of the trivalent cation considered only weakly impacted the R{sub L,0} values. The dependence of the normalized dissolution rates on the temperature then appeared to be of the same order of magnitude than that of chemical composition. Moreover, it allowed determining the corresponding activation energy (E{sub A} ? 60-85 kJ.mol{sup -1}) which accounts for a dissolution driven by surface-controlled reactions. A similar conclusion was made regarding the acidity of the solution: the partial order related to (H{sub 3}O{sup +}) reaching about 0.7. Finally, the prevailing effect of the incorporation of aliovalent cations in the fluorite-type CeO{sub 2} matrix on the dissolution kinetics precluded the observation of slight effects such as those linked to the complexing agents or to the crystal structure of the samples. (authors)

Horlait, D.; Clavier, N.; Szenknect, S.; Dacheux, N.; Dubois, V. [ICSM, CEA CNRS UM2 ENSCM, UMR 5257, F-30207 Bagnols Sur Ceze, (France)

2012-03-15

436

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

437

Chemical composition of ground water in the Yucca Mountain area, Nevada, 1971-84  

USGS Publications Warehouse

Fifteen wells in the Yucca Mountain area of southern Nevada have been sampled for chemical analysis. Samples were obtained by pumping water from the entire well bore (composite sample), and, in three instances, by pumping from one or more isolated intervals within a well bore. Sodium is the most abundant cation , and biocarbonate is the most abundant anion in all water samples. Samples from the Paleozoic carbonate aquifer penetrated by well UE-25p 1 contain higher relative concentrations of calcium and magnesium than samples from overlying volcanic tuffs. Values of the stable isotope concentrations of oxygen and hydrogen are relatively negative (light) and have deuterium excess values ranging from +5 to +10. The distribution of uncorrected radiocarbon ages of tuffaceous groundwater from samples within one kilometer of the exploratory block ranges from 12,000 to 18,500 years before present. Variation in the inorganic, stable, and radioactive isotope composition of samples indicates a significant degree of lateral and vertical chemical inhomogeneity in groundwater of the Yucca Mountain area. (USGS)

Benson, L.V.; McKinley, P.W.

1985-01-01

438

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

439

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

440

Effect of bio-regulator and foliar fertilizers on chemical composition and yield of soybean.  

PubMed

Current study evaluates the effects of bio-regulator associated with foliar fertilizers on the yield components, productivity and chemical composition of soybean. The experimental design was entirely randomized blocks, with four replications. The treatments consisted of: T1-absolute control, T2-application of 0.25 L h(-1) Stimulate in R1 stage of development, T3-application of 0.25 L h(-1) Stimulate and 3 L h(-1) Sett in R1, T4-application of 0.25 L h(-1) Stimulate and 3 L h(-1) Sett in R1 and 0.25 L h(-1) Stimulate and 2 L h(-1) Mover in R5.1; T5-application of 0.25 L h(-1) Stimulate and 3 L h(-1) Sett in R1 and 2 L h(-1) Mover in R5.1, T6-application of 3 L h(-1) Sett in R1 and 0.25 L h(-1) Stimulate and 2 L h(-1) Mover in R5.1 and T7-application of 0.25 L h(-1) Stimulate and 2 L h(-1) Mover in R1. Application of Sett and Mover is a potentially efficient handling as it favors the soybean agronomic performance in R1 stage. Chemical composition of processed grains has influence with applying bio-regulator and foliar fertilizers. PMID:24511692

Piccinin, Gleberson Guillen; Braccini, Alessandro Lucca; da Silva, Luiz Henrique; Mariucci, Giovanna Emanuêlle Gonçalves; Suzukawa, Andréia Kazumi; Dan, Lilian Gomes de Morais; Tonin, Telmo António

2013-11-15

441

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

442

Chemical Accelerators The phrase "chemical accelerators"  

E-print Network

that there is a wealth of important chemistry occurring only at higher energies (of the order of the strength of chemicalMeetings 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

Zare, Richard N.

443

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

444

The Chemical Composition of Fogs and Clouds in the United States  

NASA Astrophysics Data System (ADS)

Over the past 15 years we have investigated the chemical and physical properties of fogs and clouds at approximately twenty locations across the United States. Sampling sites have been located in the northeast, southeast, Rocky Mountain, west coast, Pacific Northwest, and Gulf Coast, and in the Pacific (airborne and in Hawaii). They include both pristine and heavily polluted locations. Frontal/orographic clouds (warm and supercooled), coastal and marine stratiform clouds and radiation fogs have all been examined. Measurements at these various locations include "bulk" and/or drop size-resolved cloud drop composition. A variety of single and multi-stage cloud/fog collectors have been developed and used for these studies. Measured species include inorganic ions, organic acids, S(IV), hydrogen peroxide, trace metals, total organic carbon and carbonyls. Observed cloud and fog pH values ranged from below 3 to above 7. Strong variations in composition as a function of drop size are seen at many locations. Because droplet deposition processes depend strongly on drop size, knowledge of drop size-dependent composition is important for understanding fog solute deposition fluxes. This presentation will review sampling approaches and highlight key features of fog and cloud composition and its variation between locations, with time, and as a function of droplet size.

Collett, J. L.; Bator, A.; Chang, H.; Demoz, B.; Herckes, P.; Hoag, K.; Lee, T.; Moore, K. F.; Raja, S.; Rao, X.; Reilly, J.; Rinehart, L.; Sherman, D. E.; Straub, D. J.; Xu, G.; Youngster, S.; Yu, X.; Ravikrishna, R.; Valsaraj, K.

2006-12-01

445

Silica-Titania Composite Aerogel Photocatalysts by Chemical Liquid Deposition of Titania onto Nanoporous Silica Scaffolds.  

PubMed

Silica-titania composite aerogels were synthesized by chemical liquid deposition of titania onto nanoporous silica scaffolds. This novel deposition process was based on chemisorption of partially hydrolyzed titanium alkoxides from solution onto silica nanoparticle surfaces and subsequent hydrolysis and condensation to afford titania nanoparticles on the silica surface. The titania is homogeneously distributed in the silica-titania composite aerogels, and the titania content can be effectively controlled by regulating the deposition cycles. The resultant composite aerogel with 15 deposition cycles possessed a high specific surface area (SSA) of 425 m(2)/g, a small particle size of 5-14 nm, and a large pore volume and pore size of 2.41 cm(3)/g and 18.1 nm, respectively, after heat treatment at 600 °C and showed high photocatalytic activity in the photodegradation of methylene blue under UV-light irradiation. Its photocatalytic activity highly depends on the deposition cycles and heat treatment. The combination of small particle size, high SSA, and enhanced crystallinity after heat treatment at 600 °C contributes to the excellent photocatalytic property of the silica-titania composite aerogel. The higher SSAs compared to those of the reported titania aerogels (<200 m(2)/g at 600 °C) at high temperatures combined with the simple method makes the silica-titania aerogels promising candidates as photocatalysts. PMID:25664480

Zu, Guoqing; Shen, Jun; Wang, Wenqin; Zou, Liping; Lian, Ya; Zhang, Zhihua

2015-03-11

446

Surface of Lactic Acid Bacteria: Relationships between Chemical Composition and Physicochemical Properties  

PubMed Central

The surface chemical composition and physicochemical properties (hydrophobicity and zeta potential) of two lactic acid bacteria, Lactococcus lactis subsp. lactis bv. diacetilactis and Lactobacillus helveticus, have been investigated using cells harvested in exponential or stationary growth phase. The surface composition determined by X-ray photoelectron spectroscopy (XPS) was converted into a molecular composition in terms of proteins, polysaccharides, and hydrocarbonlike compounds. The concentration of the last was always below 15% (wt/wt), which is related to the hydrophilic character revealed by water contact angles of less than 30°. The surfaces of L. lactis cells had a polysaccharide concentration about twice that of proteins. The S-layer of L. helveticus was either interrupted or crossed by polysaccharide-rich compounds; the concentration of the latter was higher in the stationary growth phase than in the exponential growth phase. Further progress was made in the interpretation of XPS data in terms of chemical functions by showing that the oxygen component at 531.2 eV contains a contribution of phosphate in addition to the main contribution of the peptide link. The isoelectric points were around 2 and 3, and the electrophoretic mobilities above pH 5 (ionic strength, 1 mM) were about ?3.0 × 10?8 and ?0.6 × 10?8 m2 s?1 V?1 for L. lactis and L. helveticus, respectively. The electrokinetic properties of the latter reveal the influence of carboxyl groups, while the difference between the two strains is related to a difference between N/P surface concentration ratios, reflecting the relative exposure of proteins and phosphate groups at the surface. PMID:10831437

Boonaert, Christophe J. P.; Rouxhet, Paul G.

2000-01-01

447

Effect of Chemical Structure and Composition of the Resin Phase on Vinyl Conversion of Amorphous Calcium Phosphate-filled Composites  

PubMed Central

The objective of this study was to elucidate the effect of chemical structure and composition of the polymer matrix on the degree of vinyl conversion (DC) of copolymers (unfilled resins) and their amorphous calcium phosphate (ACP) composites attained upon photo-polymerization. The DC can also be an indicator of the relative potential of these polymeric materials to leach out into the oral environment un-reacted monomers that could adversely affect their biocompatibility. The following resins were examined: 1) 2,2-bis[p-(2?-hydroxy-3?-methacryloxypropoxy)phenyl]propane (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (1:1 mass ratio; BT resin) combined with hydroxyethyl methacrylate (HEMA; BTH resin) and with HEMA and zirconyl dimethacrylate (BTHZ resin), 2) urethane dimethacrylate (UDMA)/HEMA resins, and 3) pyromellitic glycerol dimethacrylate (PMGDMA)/TEGDMA (PT resin). To make composite specimens, resins were mixed with a mass fraction of 40 % zirconia-hybridized ACP. Copolymers and their composites were evaluated by near infra-red spectroscopy for DC after 1 d and 28 d post-cure at 23 °C. Inclusion of HEMA into the BT and UDMA resins yielded copolymers and composites with the highest DCs. The significantly lower DCs of PT copolymers and their composites are attributed to the rigid aromatic core structure, tetra-vinyl functionality and limited methacrylate side-chain flexibility of the surface-active PMGDMA monomer. There was, however, an increase in the 28 d DC for the PT materials as there was for the BTHZ system. Surprisingly, the usual decrease observed in DC in going from unfilled polymer to composite was reversed for the PT system. PMID:18714369

Skrtic, D.; Antonucci, J.M.

2008-01-01

448

Transport-induced shifts in condensate dew-point and composition in multicomponent systems with chemical reaction  

NASA Technical Reports Server (NTRS)

Partial heterogeneous condensation phenomena in multicomponent reacting systems are analyzed taking into consideration the chemical element transport phenomena. It is demonstrated that the dew-point surface temperature in chemically reactive systems is not a purely thermodynamic quantity, but is influenced by the multicomponent diffusion and Soret-mass diffusion phenomena. Several distinct dew-points are shown to exist in such systems and, as a result of transport constraints, the 'sharp' locus between two chemically distinct condensates is systematically moved to a difference mainstream composition.

Rosner, D. E.; Nagarajan, R.

1985-01-01

449

Chemical vapor deposition of organosilicon composite thin films for porous low-k dielectrics  

E-print Network

Pulsed plasma enhanced chemical vapor deposition has produced organosilicon thin films with the potential use as low dielectric constant interconnect materials in microelectronic circuits. Both diethylsilane and ...

Ross, April Denise, 1977-

2005-01-01

450

Tracing the evolution of NGC 6397 through the chemical composition of its stellar populations  

NASA Astrophysics Data System (ADS)

Context. The chemical compositions of globular clusters provide important information on the star formation that occurred at very early times in the Galaxy. In particular the abundance patterns of elements with atomic number z ? 13 may shed light on the properties of stars that early on enriched parts of the star-forming gas with the rest-products of hydrogen-burning at high temperatures. Aims: We analyse and discuss the chemical compositions of a large number of elements in 21 red giant branch stars in the metal-poor globular cluster NGC 6397. We compare the derived abundance patterns with theoretical predictions in the framework of the "wind of fast rotating massive star"-scenario. Methods: High-resolution spectra were obtained with the FLAMES/UVES spectrograph on the VLT. We determined non-LTE abundances of Na, and LTE abundances for the remaining 21 elements, including O (from the [OI] line at 630 nm), Mg, Al, ?, iron-peak, and neutron-capture elements, many of which had not been previously analysed for this cluster. We also considered the influence of possible He enrichment in the analysis of stellar spectra. Results: We find that the Na abundances of evolved, as well as unevolved, stars in NGC 6397 show a distinct bimodality, which is indicative of two stellar populations: one primordial stellar generation of composition similar to field stars, and a second generation that is polluted with material processed during hydrogen-burning, i.e., enriched in Na and Al and depleted in O and Mg. The red giant branch exhibits a similar bimodal distribution in the Strömgren colour index cy = c1 - (b - y), implying that there are also large differences in the N abundance. The two populations have the same composition for all analysed elements heavier than Al, within the measurement uncertainty of the analysis, with the possible exception of [Y/Fe]. Using two stars with almost identical stellar parameters, one from each generation, we estimate the difference in He content, ?Y = 0.01 ± 0.06, given the assumption that the mass fraction of iron is the same for the stars. Conclusions: NGC 6397 hosts two stellar populations that have different chemical compositions of N, O, Na, Mg, and probably Al. The cluster is dominated (75%) by the second generation. We show that massive stars of the first generation can be held responsible for the abundance patterns observed in the second generation long-lived stars of NGC 6397. We estimate that the initial mass of this globular cluster is at least ten times higher than its present-day value. Based on data collected at European Southern Observatory (ESO), Paranal, Chile, under program IDs 077.A-0018(A) and 281.D-5028(A), as well as data collected with the Danish 1.54 m at European Southern Observatory (ESO), La Silla.Tables A.1 and A.2 are only available in electronic form at http://www.aanda.orgTwo tables with line equivalent widths, chemical abundances, and stellar parameters are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A148

Lind, K.; Charbonnel, C.; Decressin, T.; Primas, F.; Grundahl, F.; Asplund, M.

2011-03-01

451

Chemical composition of melanosomes, lipofuscin and melanolipofuscin granules of human RPE tissues.  

PubMed

Energy-filtered analytical transmission electron microscopy was used to image the ultrastructure and determine quantitatively the chemical composition of pigment granules of the choroid and retinal pigment epithelium of two healthy human donors, aged 68 and 85 years. The electron microscopy preparation procedure did not affect the autofluorescence of melanolipofuscin and lipofuscin granules, since staining was omitted during sample preparation. Oval melanosomes, melanolipofuscin and lipofuscin granules were observed, having sizes of about 1.5 ?m×0.5 ?m, and were analyzed using energy-dispersive X-ray microanalysis and electron energy loss spectroscopy. Up to now, these pigments could only be identified by scattering contrast in bright field images, with melanosomes having dark contrast and lipofuscin being much brighter. High-precision energy-dispersive X-ray microanalysis of pigment granules (>15,000 integrated counts in the oxygen K(?) peak) yielded minimum detectable mole fractions of about 0.02 at% for copper and zinc. For the first time, quantitative analytical electron microscopy yielded the chemical composition of the different pigments without prior isolation from the tissue. This is important to better understand physical and chemical properties of the pigments and their metabolism and turnover. The composition of melanosomes and lipofuscin can clearly be distinguished by the applied methods. Melanosomes were the pigments with largest oxygen (about 5 at%) and nitrogen (about 10 at%) mole fractions. The S/N ratio determination demonstrated a high pheomelanin content of the melanosomes. Lipofuscin had a significantly smaller oxygen mole fraction (about 4 at%) and nitrogen was found to be only slightly above the limit of detection (0.4 at%). For comparison, the cytoplasm contained oxygen and nitrogen mole fractions of 3 at% and 0.8 at%. Bright field images showed melanolipofuscin granules having a core-shell structure with a dark inner and a bright outer fraction. The dark fraction had a chemical composition close to the melanosomes and the composition of the bright fraction could be distinguished from that of lipofuscin due to a significantly increased nitrogen mole fraction in the melanolipofuscin granule. For all pigments observed the oxygen mole fraction yielded a positive correlation with the calcium mole fraction as previously established for melanosomes. Only lipofuscin contained measurable phosphorus mole fractions, which also correlated positively with oxygen. In lipofuscin, mole fractions of nitrogen were significantly smaller than in melanosomes and only indicated a small fraction of proteins. In contrast, the phosphorus mole fraction was significantly larger indicating the presence of significant amounts of phospholipids. Copper and zinc mole fractions were larger than 0.1at% in the melanosomes, but were below the detection limit in the lipofuscin granules. Compared to melanosomes of monkeys and rats analyzed beforehand, human retinal pigment epithelium melanosomes contained the highest amount of zinc, which even exceeded the calcium mole fraction. Trace elements like zinc are of great importance for metabolism and anti-oxidative mechanisms and also play a role in the progression of age related macular degeneration. They can now be investigated by quantitative analytical electron microscopy. PMID:21524648

Biesemeier, Antje; Schraermeyer, Ulrich; Eibl, Oliver

2011-07-01

452

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 remov