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1

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

2

Chemical composition of patikaraparpam.  

PubMed

Patikaraparpam, a Siddha formulation in prepared by trituration of potash alum with egg albumin followed by calcinatin. The three authentic laboratories made parpams as well as six commercial samples have been examined for their chemical composition. The analytical data that emerged from the analysis of the above samples showed that seven parpams contained only aluminium sulphate and they did respond to tests for potassium. An inspection of the crude drugs patikaram' available in the market established that potash alum and ammonia alum are indiscriminateldy taken for use, according to literature, only potash alum should be used in Indian system of medicine. Patikarapparapam is indicated in urinary inflammations and obstructions and is a reputed diuretic. Potassium salts are established diuretic. These studies show that the raw drugs sellers, the pharamaceutists or manufacturers of medicine and the physician as well should make sure that only potash alum is used in Indian medicine. PMID:22556804

Saraswathy, A; Rani, M G; Susan, T; Purushothaman, K K

1997-04-01

3

CHAPTER XVII CHEMICAL COMPOSITION  

E-print Network

L___________________________________________ 382 Inorganic constltuents____________ __ __ ___ _ __ __ _ 383 Iodine the tissues and organs, exclusive of skeleton or shells, consists of three major groups of organic eompounds is blown through it to remove grit, pieces of broken shell, and mud. The pro- cedure affects the chemical

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

Chemical composition of Mars  

USGS Publications Warehouse

The composition of Mars has been calculated from the cosmochemical model of Ganapathy and Anders (1974) which assumes that planets and chondrites underwent the same 4 fractionation processes in the solar nebula. Because elements of similar volatility stay together in these processes, only 4 index elements (U, Fe, K and Tl or Ar36) are needed to calculate the abundances of all 83 elements in the planet. The values chosen are U = 28 ppb, K = 62 ppm (based on K U = 2200 from orbital ??-spectrometry and on thermal history calculations by Tokso??z and Hsui (1978) Fe = 26.72% (from geophysical data), and Tl = 0.14 ppb (from the Ar36 and Ar40 abundances measured by Viking). The mantle of Mars is an iron-rich [Mg/(Mg + Fe) = 0.77] garnet wehrlite (?? = 3.52-3.54 g/cm3), similar to McGetchin and Smyth's (1978) estimate but containing more Ca and Al. It is nearly identical to the bulk Moon composition of Morgan et al. (1978b). The core makes up 0.19 of the planet and contains 3.5% S-much less than estimated by other models. Volatiles have nearly Moon-like abundances, being depleted relative to the Earth by factors of 0.36 (K-group, Tcond = 600-1300 K) or 0.029 (Tl group, Tcond < 600 K). The water abundance corresponds to a 9 m layer, but could be higher by as much as a factor of 11. Comparison of model compositions for 5 differentiated planets (Earth, Venus, Mars, Moon, and eucrite parent body) suggests that volatile depletion correlates mainly with size rather than with radial distance from the Sun. However, the relatively high volatile content of shergottites and some chondrites shows that the correlation is not simple; other factors must also be involved. ?? 1979.

Morgan, J.W.; Anders, E.

1979-01-01

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

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

8

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

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 Modification of Nanotubes for Composites  

NASA Technical Reports Server (NTRS)

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

Samulski, Edward T.

2003-01-01

11

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

12

Chemical production of chondrule oxygen isotopic composition  

NASA Technical Reports Server (NTRS)

Defining the source of observed meteoritic O isotopic anomalies remains a fundamental challenge. The O isotopic composition of chondrules are particularly striking. There are at least three types of chemical processes that produce the isotopic compositions observed in chondrules and Ca-Al-rich inclusions (CAI's). The processes are rather general, viz, they require no specialized processes and the processes associated with chondrule production are likely to produce the observed compositions.

Thiemens, M. H.

1994-01-01

13

Chemical Composition of Soils of Texas.  

E-print Network

and semi-marshy soils, and (4) flat stream bottom soils. CHEMICAL COMPOSITION OF SOILS OF TEXAS 15 Outline description of series L-colored prairie soils: ke Charles soils: Black, dark-gray or brown, noncalcareous surface soils ? tight on drying... and semi-marshy soils, and (4) flat stream bottom soils. CHEMICAL COMPOSITION OF SOILS OF TEXAS 15 Outline description of series L-colored prairie soils: ke Charles soils: Black, dark-gray or brown, noncalcareous surface soils ? tight on drying...

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

1937-01-01

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

Original article Anatomy and chemical composition  

E-print Network

Original article Anatomy and chemical composition of Pinus pinea L. bark Elsa Nunesa Teresa Quilhób and axial and radial parenchyma, but no fibres. Resin ducts are present in fusiform rays. Styloid crystals-walled cells with inclu- sions and sometimes a layer of expanded cells. Ash content of P. pinea bark is low

Paris-Sud XI, Université de

16

Chemical composition of Galactic H II regions.  

NASA Astrophysics Data System (ADS)

A review of the chemical compositions of M8, M17 and M42 (Orion) is presented. Observational evidence on the presence of spatial temperature variations inside H II regions is presented; these variations can be explained by photoionization models of nebulae with uniform distributions of dust and chemical composition. Possible causes of these temperature variations are analyzed. Abundance tables with probable errors (1?) for Orion, M8 and M17 are presented. These abundances are compared with those of the Sun and B stars of the solar neighborhood. The abundances of Galactic H II regions are compared with those of extragalactic H II regions; the enrichment of the carbon abundance and the ?Y/?Z value are briefly discussed.

Peimbert, M.

1993-11-01

17

Systems With Variable Composition: The Chemical Potential Chemistry 223  

E-print Network

or 2) by changing the composition through chemical reaction. Nonetheless, as far as state functions, number of moles, etc.) and where µi,op is called the opposing chemical potential (and is analogous to the opposing pres- sure). For reversible processes, the opposing chemical potential equals the chemical

Ronis, David M.

18

Chemical composition of Texas surface waters, 1949  

USGS Publications Warehouse

This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, and nitrate are reported in parts per million. The quantity of dissolved solids is given in tons per acre-foot, tons per day (if discharge records are available), and parts per million. The total and non-carbonate hardness are reported as parts per million calcium carbonate (CaCO3). For those analyses where sodium and potassium are reported separately, "recent sodium" will include the equivalent quantity of sodium only. In analyses where sodium and potassium were calculated and reported as a combined value, the "percent sodium" will include the equivalent quantity of sodium and potassium. Weighted average analyses are given for most daily sampling stations. The weighted average analysis represent approximately the composition of water that would be found in a reservoir containing all the water passing a given station during the year after through mixing in the reservoir. Samples were analyzed according to method regularly used by the Geological Survey. These methods are essentially the same or are modifications of methods described in recognized authoritative publications for mineral analysis of water samples. These quality of water records have been collected as part of the cooperative investigations of the water resources of Texas conducted by the Geological Survey and the Texas Board of Water Engineers. Much of the work would have been impossible without the support of the following Federal State, and local agencies The United States Bureau of Reclamation, U. S. Corps of Engineers, Brazos River Conservation and Reclamation District, Lower Colorado River Authority, Red Bluff Water Power Control District, City of Amarillo, City of Abilene, and City of Forth Worth. The investigations were under the firection of Burdge Irelan, District Chemist, Austin, Texas. Analyses of water samples were made by Clara J. Carter, Lee J. Freeman, Homer D. Smith, Dorothy M. Suttle, DeForrest E. Weaver, and Clarence T. Welborn. Calculations of weighted averages were made by James R. Avrett, Burdge Irelan, Dorothy M. Suttle, and DeFor

Irelan, Burdge

1950-01-01

19

Globally convergent computation of chemical equilibrium composition.  

PubMed

We report the Newton-Raphson based globally convergent computational method for determination of chemical equilibrium composition. In the computation of chemical equilibrium composition, an appearance of nonpositive value of number of moles of any component leads to discrepancy. The process of conditional backtracking and adaptive set of refining factors for Newton-Raphson steps are employed to resolve the problem. The mathematical formulation proposed by Heuze et al. (J Chem Phys 1985, 83, 4734) has been solved using proposed computational method, instead of empirical iterative formulation, as proposed by them. Results for the same numerical example, used by Heuze et al. (J Chem Phys 1985, 83, 4734) and White et al. (J Chem Phys 1958, 28, 751) are presented in addition to decomposition of Cyclotrimethylenetrinitramine for fixed temperature and pressure. It is observed that the proposed method is efficient and globally convergent. An even noteworthy finding is that the set of refining factors can be chosen from the range 0.1 to eta, where eta may be greater than one depending on how smoothly system of nonlinear equations is dependant on corresponding variable. Related analysis and results are discussed. PMID:18161685

Patil, Sunil; Aiyer, R C; Sharma, K C

2008-05-01

20

Biological resistance of chemically modified aspen composites  

Microsoft Academic Search

Aspen wood (Populus tremula L.) was chemically modified by a two-step procedure consisting of esterification with maleic anhydride (MA) and subsequent oligoesterification with MA and glycidyl methacrylate (GMA) or allyl glycidyl ether (AGE). This chemical modification procedure was carried out on solid wood, veneers and sawdust. The modified wood showed thermoplastic properties and could be thermally formed by hot-pressing. As

M. C Timar; A Pitman; M. D Mihai

1999-01-01

21

Analysis of chemical compositions contributable to chemical oxygen demand (COD) of oilfield produced water  

Microsoft Academic Search

This work was to give a comprehensive estimation for the chemical compositions contributable to COD of the produced water treatment system. For this purpose, the wastewater samples were collected from an onshore wastewater treatment plant. The chemical compositions of the wastewater were investigated, and the COD contributed by each component was estimated. The results showed that the COD levels of

Jinren Lu; Xiulin Wang; Baotian Shan; Ximing Li; Weidong Wang

2006-01-01

22

Chemical Composition of Soils of Northwest and West Central Texas.  

E-print Network

.......................................................................................................... I BULLETIN No. 443 MARCH, 1932 et a Rc the : ture 0 CHEMICAL COMPOSITION OF SOILS OF NORTHWEST AND WEST CENTRAL TEXAS G. S. FRAPS The diatelj squarc w This Bulletin deals with the chemical composition and fertility of samples of typical... with the chemical composition of typical Texas soils. Detailed reports of the surveys with maps of the areas showing the location of the soil types have been published by the Bureau of Chemistry and Soils, United States Department of Agriculture. Description...

Fraps, G. S. (George Stronach)

1932-01-01

23

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

24

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

25

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

26

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

27

FUNDAMENTAL PARAMETERS AND CHEMICAL COMPOSITION OF ARCTURUS  

SciTech Connect

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

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

2011-12-20

28

Chemical Corrosion Effect on Wood and Wood–Plastic Composites  

Microsoft Academic Search

Effect of chemical corrosion on the tensile strengths of five types of Bangladeshi timbers (kadom, simul, koroi, mango, and debdaro) and their composites has been evaluated. Wood–plastic composites (WPC) formed by the gamma-radiation induction polymerization of butylmethacrylate (BMA) with those timbers show better resistance to chemical corrosion attack than the parent timbers. Enhanced mechanical properties such as tensile strength of

M. A. Khan; K. M. Idriss Ali; M. U. Ahmed

1993-01-01

29

The classification of ordinary chondrites according to chemical composition  

NASA Astrophysics Data System (ADS)

Recent data on the chemical classification of ordinary chondrites are examined. Graphs are presented which serve to separate these chondrites into types H, L, and LL according to bulk chemical composition and mineral composition (pyroxene, olivine, kamacite). Examples of ordinary chondrites of other types are indicated, along with anomalous meteorites that belong to this group of chondrites.

Iavnel, A. A.

30

Preparation and characterization of ceramic composites and coatings by chemical vapor deposition and chemical vapor infiltration  

Microsoft Academic Search

Chemical vapor deposition or chemical vapor infiltration is a deposition process in which a solid phase is produced and condensed onto a substrate via chemical reaction of gases. Ceramic composites, Si\\/SiC, as well as coatings, Ti, TiN, C, W were produced by using this technique. Several characterization methods, including SEM, XRD, AES, XPS, and optical microscopy, were employed to investigate

Hwan; Luchen

1990-01-01

31

Chemical compositions of large cluster IDPs  

SciTech Connect

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

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

2006-12-06

32

Ethylene vinylacetate copolymer and nanographite composite as chemical vapour sensor  

NASA Astrophysics Data System (ADS)

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

Stepina, Santa; Sakale, Gita; Knite, Maris

2013-12-01

33

Chemical composition of major ions in rainwater.  

PubMed

The present study investigated the chemical composition of rainwater at Kabir nagar, Nari, Nagpur, Maharashtra, India. The rainwater samples were collected on event basis during June-July-August-2006 and were analyzed for pH, major anions Cl, NO(3), SO(4)) and cations (Ca, Mg, Na, K, NH4). The pH value varied from 6.0 to 7.3 (avg. 6.3 +/- 0.3) indicating alkaline nature of rainwater. The pH of the rainwater was found well above the reference pH (5.6), showing alkalinity during the monsoon season. The average and standard deviation of ionic composition was found to be 98.1 +/- 10.6 micro eql(-1). The total anions contribute 45.1% and cations 54.9%, respectively to rainwater. Neutralization factors (NF) followed a sequence of NF(Ca) > NF(Mg) > NF(NH4) with factors of 1.1, 0.38 and 0.15 indicating the crustal components are responsible for neutralization of anions. The average ratio of (NO(3) + Cl)/SO(4) observed as 1.1 indicates that nitric and hydrochloric acid influences the acidity of rainwater. The ratio of NH(4)/NO(3) and NH(4)/SO(4) was observed as 0.68 and 0.34 indicate that the possible compounds which may predominate in the atmosphere are NH(4)NO(3) and (NH(4))(2)SO(4). Ionic correlation was established to identify sources of origin. A good correlation was seen between Ca and Mg (r = 0.95); suggesting the common occurrence of these ions from crustal origin. Similarly, the acidic ions SO(4) and NO(3) correlated well (r = 0.60) indicating their origin from similar sources. Other relatively significant correlations were observed between Ca and SO4 (r = 0.92), Mg and SO(4) (r = 0.83), Ca and NO(3) (r = 0.09), Ca and Cl (r = 0.34) and Mg and Cl (r = 0.31), and Mg and NO(3) (r = 0.71). The observed rainwater ratio of Cl/Na (1.1) is closer to that of seawater ratio (1.16) indicates fractionation of sea-salt and modifications by non-marine constituents as the site is 834 km away from the sea coast. The nss-Ca contribution was observed as 95.7% suggesting their crustal origin whereas nss-Mg and nss-K shows their contribution as 87.9% and 83.2% indicating influence of soil sources. The nss-SO(4) contributed as 87.4% shows anthropogenic origin. PMID:18196188

Salve, P R; Maurya, A; Wate, S R; Devotta, Sukumar

2008-03-01

34

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

35

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

E-print Network

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

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

2008-04-23

36

Chemically coupled hydroxyapatite-polyethylene composites: processing and characterisation  

Microsoft Academic Search

Hydroxyapatite (HA)-reinforced polyethylene was developed as a bone replacement material. In order to improve bonding between HA and polyethylene, and hence to increase mechanical properties of the composite, chemical treatments of HA and polyethylene were investigated and new composites manufactured. Two approaches were employed in this investigation: the use of silane-treated HA as the filler, and the application of polymer

M Wang; S Deb; W Bonfield

2000-01-01

37

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

38

Studies on surface composition and chemical states of calcium manganites  

Microsoft Academic Search

This paper describes investigations on atomic composition and chemical states of sintered calcium manganites discs in surface and near surface regions. The atomic composition was determined by 3.05MeV 16O(?,?)16O resonance elastic scattering while the chemical states by, X-ray photoelectron spectroscopy (XPS). The specimens examined included undoped and donor (Y3+, Bi3+) doped CaMnO3, and Ca-excess and Mn-excess manganites namely Ca2MnO4 and

Sanjiv Kumar; V. S. Raju; Santanu Bera; K. Vijaynandhini; T. R. N. Kutty

2005-01-01

39

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

40

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

41

Chemical composition of Hanford Tank SY-102  

SciTech Connect

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

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

1993-12-01

42

Major element chemical compositions of chondrules in unequilibrated chondrites  

NASA Technical Reports Server (NTRS)

The chemical compositions (except for metals and sulfides in chondrules) of more than 500 chondrules from unequilibrated E, H, L, LL, and C chondrites were measured using a broad beam of an electron-probe microanalyzer. The compositions of chondrules can be represented by various mixtures of normative compositions of olivine, low-Ca pyroxene, plagioclase, and high-Ca pyroxene with minor amounts of spinel, feldspathoid, SiO2-minerals, etc., indicating that the chondrule precursor materials consisted of aggregates of these minerals. The Al, Na, and K contents of most chondrules reflect the compositions of the ternary feldspar (An-Ab-Kf) of the chondrule precursor materials, and chemical types of chondrules (KF, SP, IP, and CP) are defined on the basis of the atomic proportion of Al, Na, and K.

Ikeda, Y.

1984-01-01

43

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

44

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

45

Chemical Composition of Variants of Aerobic Actinomycetes  

PubMed Central

It has been shown previously that aerobic actinomycetes can be separated into four main groups on the basis of their cell wall composition. Six representatives of aerobic actinomycetes (Nocardia asteroides and Micropolyspora brevicatena, cell wall type IV; N. madurae, Microbispora rosea, cell wall type III; Actinoplanes sp., cell wall type II; Streptomyces griseus, cell wall type I) were subjected to selecting agents which permitted the isolation of stable variants morphologically different from the parent strain. Whole cell analyses of 134 substrains from the six parents revealed no significant change in the isomeric form of diaminopimelic acid or in sugar constituents. Analyses of cell wall preparations from 52 of these did not reveal any change in the diagnostic constituents of their murein or polysaccharides. PMID:16349745

Suput, Jelena; Lechevalier, Mary P.; Lechevalier, H. A.

1967-01-01

46

Chemical composition and microstructure of Bauhinia grains.  

PubMed

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

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

2014-09-01

47

The Chemical Composition of the Cotton Plant.  

E-print Network

the degree of maturity of the bolls when the samples were collected. The feeding value is not nearly as high as that of the leaves. Table 10-Feeding Composition Cotton Leaves. Protein Ether Crude gen-free Water Ash 1 tract Fibre 1~::;itl 1 Table 10... Fibre Extract 3179 Cotton Bolls. .............. 23.94 43.75 5.33 .......... 6655 Mebane Triumph. ........ 1 1 z:;: 4 4. 5 : 6.94 3674 Long Staple Cotton. 7.35 3.05 42.49 35.08 6.34 5.69 ........... 6679 Mebane Cotton.. 7.58 4.07 43.99 32.24 8.85 3...

Fraps, G. S. (George Stronach)

1919-01-01

48

Chemical vapor infiltration of non-oxide ceramic matrix composites  

SciTech Connect

Continuous fiber ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being investigated, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide- based materials are, by far, the most mature, and are already being used in aerospace applications. This paper addresses the state-of-the-art of the technology and outlines current issues.

Besmann, T.M.; Stinton, D.P.; Lowden, R.A.

1993-12-31

49

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

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, 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

52

Influence of Chemical Composition on the Isothermal Cocoa Butter Crystallization  

Microsoft Academic Search

The influence of chemical composition on the isothermal cocoa butter crystallization was investigated quantitatively. Apart from the fatty acid and triacylglycerol profile, the amounts of some minor components (diacylglycerols, free fatty acids, phospholipids, soap, unsaponifiable matter, iron, and primary oxidation products) were determined. With the forward model selection technique, a multiple linear regression model was established, showing the influence of

I. Foubert; P. A. Vanrolleghem; O. Thas; K. Dewettinck

2006-01-01

53

Chemical composition, toxicity and mosquito repellency of Ocimum selloi oil  

Microsoft Academic Search

Ocimum spp. (Lamiaceae) and their essential oils have been traditionally used to kill or repel insects, and also to flavor foods and oral products, in fragrances, in folk medicine and as condiments. In Brazil, Ocimum selloi has been used to treat stomachaches and as an anti-inflammatory remedy. This study was performed to provide data on the chemical composition, acute toxicity,

Josiane Padilha de Paula; Maria Regina Gomes-Carneiro; Francisco J. R Paumgartten

2003-01-01

54

Chemical composition of Schiff's reagent crystals.  

PubMed

Crystals were prepared by adding 0.04 M sulfuric acid to a Schiff's reagent made with 2.5 g pararosaniline (PR) chloride dissolved in a saturated SO2 solution. Elemental analysis of the crystals gave the composition C19H21N3S2O7.4H2O which corresponds to the sulfate of pararosanilinesulfonic acid (PRSA) tetrahydrate. The moisture content was ca. 5%. A reagent reconstituted by dissolving 0.2 grams of crystals in HCl 0.1 N contains ca. 3.5 x 10(-3) M or 0.11% PR. A solution prepared with 2.5 g PR in 100 ml O.1 N HCl plus 0.04 M M K2S2O5 gave only a few crystals after 0.04 M sulfuric acid was added. The PR content, determined colorimetrically, was 0.25% compared with 1.35% in saturated SO2. The per cent dye loss during charcoal purification was also higher. The low concentration of PR, caused both by the lower solubility and by the larger loss during charcoal purification explains the poor yield of crystals of a reagent prepared in HCl/K2S2O5, compared to a reagent prepared in saturated SO2. After crystallization is complete, the crystals are in equilibrium with a concentration of 0.2% of PR in the supernatant: when the initial concentration is close to this value crystallization is negligible or completely fails. PMID:8835187

Galassi, L; De Napoli, F

1995-01-01

55

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

56

Effect of Chemical Composition on Texture Using Response Surface Methodology  

NASA Astrophysics Data System (ADS)

This study explores the effect of annealing temperature and chemical composition on crystallographic texture evolution of commercially pure aluminium alloy sheets using response surface methodology (RSM). The orientation of the crystal structure in Euler space using Bunge notation has been studied to know the behavior of the metal and estimate its volume fraction. The experimental procedure involves texture analysis with respect to annealing temperature and chemical composition in correlation with the results of formability and use of RSM. The effect of important input parameters, namely, annealing temperature and chemical composition (impurities) was used for predicting the numerical models using the volume fraction of texture output from the crystallographic study using Design Expert 8.0.7.1, trial software. Also this study explains the effect of individual chemical components, namely, iron, silicon, and copper in evolution of texture components. The volume fraction of Cube {1 0 0} <0 0 1>, Bs {1 1 0} <1 1 2>, and S {1 2 3} <6 3 4> components increase, whenever iron and copper content increase and silicon component decreases.

Velmanirajan, K.; Narayanasamy, R.; Anuradha, K.

2013-11-01

57

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

58

Chemical Composition of Galactic Cosmic Rays with Space Experiments  

E-print Network

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

Mirko Boezio; Emiliano Mocchiutti

2012-08-07

59

The Chemical Composition of Citrus Hystrix DC (Swangi)  

Microsoft Academic Search

The chemical composition of the essential oils of Swangi (Citrus hystrix DC) were investigated by gas chromatography and gas chromatography-mass spectrometry. (?)-Citronellal was characterized as the main component (81%) of the leaf oil. It was also found as the main component of the twig oil (78.64%), and a major component of the peel oil (23.64%) in combination with ?-pinene (25.93%)

Akiyoshi Sato; Kenichi Asano; Toshiya Sato

1990-01-01

60

Chemical composition of Opuntia ficus-indica (L.) fruit  

Microsoft Academic Search

Chemical composition of pulp, skin and seeds of fruit of Opuntia ficus-indica was investigated. Results showed high amount of water in the pulp (84.14%) and skin (90.33%). Glucose and fructose (29 and 24%, respectively) in the pulp were greater than in the skin (14 and 2.29%, respectively), whereas saccharose was very low in the pulp (019%) than in the skin

Nebbache Salim; Chibani Abdelwaheb; Chadli Rabah; Bouznad Ahcene

61

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

62

Measurements of aerosol chemical composition in boreal forest summer conditions  

NASA Astrophysics Data System (ADS)

Boreal forests are an important biome, covering vast areas of the northern hemisphere and affecting the global climate change via various feedbacks [1]. Despite having relatively few anthropogenic primary aerosol sources, they always contain a non-negligible aerosol population [2]. This study describes aerosol chemical composition measurements using Aerodyne Aerosol Mass Spectrometer (C-ToF AMS, [3]), carried out at a boreal forest area in Hyytiälä, Southern Finland. The site, Helsinki University SMEAR II measurement station [4], is situated at a homogeneous Scots pine (Pinus sylvestris) forest stand. In addition to the station's permanent aerosol, gas phase and meteorological instruments, during the HUMPPA (Hyytiälä United Measurements of Photochemistry and Particles in Air) campaign in July 2010, a very comprehensive set of atmospheric chemistry measurement instrumentation was provided by the Max Planck Institute for chemistry, Johannes Gutenberg-University, University of California and the Finnish Meteorological institute. In this study aerosol chemical composition measurements from the campaign are presented. The dominant aerosol chemical species during the campaign were the organics, although periods with elevated amounts of particulate sulfates were also seen. The overall AMS measured particle mass concentrations varied from near zero to 27 ?g/m observed during a forest fire smoke episode. The AMS measured aerosol mass loadings were found to agree well with DMPS derived mass concentrations (r2=0.998). The AMS data was also compared with three other aerosol instruments. The Marga instrument [5] was used to provide a quantitative semi-online measurement of inorganic chemical compounds in particle phase. Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed on daily filter samples, enabling the identification and quantification of organic aerosol subspecies. Finally an Atmospheric Pressure Chemical Ionization Ion Trap Mass Spectrometer (APCI-IT-MS, [6]) was measuring gas and particle phase aerosol composition, offering additional information on molecular compositions. Overall, the availability of a variety of aerosol chemical characterization instruments provided a good opportunity for a comparison of the results obtained by these four very different measurement approaches. Overall the results were found to agree. The inorganic particulate masses measured with the AMS and Marga were found to correlate especially well for sulphates (r2=0.92) and ammonia compounds (r2=0.82). The organic mass seen by the AMS was correlated with the FTIR filter analysis (r2=0.87) and the APCI-IT-MS (r2=0.88).

?ijälä, M.; Junninen, H.; Ehn, M.; Petäjä, T.; Vogel, A.; Hoffmann, T.; Corrigan, A.; Russell, L.; Makkonen, U.; Virkkula, A.; Mäntykenttä, J.; Kulmala, M.; Worsnop, D.

2012-04-01

63

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

64

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

65

Predicting hygroscopic growth using single particle chemical composition estimates  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

66

Titan's Interior Chemical Composition: Possible Important Phase Transitions  

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 1/1000. We find that a significant amount of nitrogen is in the form of N2, rather than NH3. Moreover, above 12 kbars pressure, 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 performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Howard, Michael; Fried, L. E.; Khare, B. N.; McKay, C. P.

2008-09-01

67

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

68

Manufacture of ceramic composites by forced chemical vapor infiltration techniques  

SciTech Connect

Forced chemical vapor infiltration (FCVI) methods have been developed to fabricate ceramic composites. The FCVI techniques allow the rapid densification of fibrous preforms with ceramic matrices. Computer-based modeling was used to develop a multi-step forced chemical vapor infiltration process. In particular, a finite-volume computer model, GTCVI, developed specifically for the FCVI process was used to determine optimal processing schemes. The results indicate that in the first step, processing conditions should be tailored to uniformly infiltrate the fine pores within fiber bundles. Once bundles are filled, conditions should be changed to compensate for new transport conditions and surface-to-volume effects associated with the coarse porosity between fiber bundles and layers of fabrics. The model-derived conditions allow processing times for a 1.3 cm thick preform to be decreased from 24 hours to 11 hours while maintaining an average final density greater than 85%.

Matlin, W.M.; Liaw, P.K. [Univ. of Tennessee, Knoxville, TN (United States); Stinton, D.P.; Besmann, T.M. [Oak Ridge National Lab., TN (United States)

1995-12-31

69

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

70

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

71

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

72

The physical and chemical composition of the lower mantle.  

PubMed

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

Bovolo, C Isabella

2005-12-15

73

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

74

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

75

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

76

Modeling of chemical vapor infiltration for composite fabrication  

SciTech Connect

We describe our ongoing efforts to develop a general, validated, 3-D, finite-volume model for the chemical vapor infiltration (CVI) process. The model simulates preform densification for both isothermal (ICVI) and forced flow-thermal gradient (FCVI) variations of the process, but is most useful for FCVI where specification and control of flow rates and temperature profiles are critical to rapid, uniform densification. The model has been validated experimentally for both ICVI and FCVI fabrication of SiC/SiC composites.

Starr, T.L. [Georgia Inst. of Tech., Atlanta, GA (United States); Besmann, T.M. [Oak Ridge National Lab., TN (United States)

1993-12-31

77

Unusual chemical compositions of noctilucent-cloud particle nuclei  

NASA Technical Reports Server (NTRS)

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

Hemenway, C. L.

1973-01-01

78

Spartium junceum aromatic water: chemical composition and antitumor activity.  

PubMed

The purpose of this study was to analyse the chemical composition of Spartium junceum L. (also known as Spanish Broom) aromatic water and to evaluate its cytotoxic activity against a series of human cancer cell lines (melanoma: RPMI 7932; leukemia: K562; breast cancer cell: MCF7-Bart and MCF7-ICLC, colon adenocarcinoma: SW480). The results show that the aromatic water was cytotoxic toward the tumor cell lines analyzed (RPMI 7932, K562, MCF7-Bart, MCF7-ICLC, SW480), while it did not appreciably alter the viability of normal keratinocytes (NCTC 2544) suggesting its potential use as an antitumor agent for cancer treatment and/or prevention. PMID:22428268

Cerchiara, Teresa; Straface, Serafina V; Chidichimo, Giuseppe; Belsito, Emilia L; Liguori, Angelo; Luppi, Barbara; Bigucci, Federica; Zecchi, Vittorio

2012-01-01

79

Chemical composition of semi-regular variable giants. III.  

NASA Astrophysics Data System (ADS)

Aims: We derive the stellar atmosphere parameters and chemical element abundances of four stars classified as semi-regular variables of type "d" (SRd). These stars should presumably belong to the Galactic halo population. Methods: Elemental abundances are derived by applying both local thermodynamical equilibrium and non-local thermodynamical equilibrium analyses to high resolution (R ? 80 000) spectra obtained with the CFHT ESPaDOnS spectrograph. We determine the abundances of 27 chemical elements in VW Dra, FT Cnc, VV LMi, and MQ Hya. Results: The stars of our present program have a chemical composition that is inconsistent with their presumable status as metal-deficient halo giants. All studied SRd giants have relative-to-solar elemental abundances that are typical of the thick/thin Galactic disk stars. We find that all objects of this class for which spectroscopic follow up analyses have been completed show a dichotomy in the amplitudes of their photometric variations. Specifically, the disk objects have small amplitudes, while halo SRd stars have much larger amplitudes, which indicates that amplitude is obviously related to the metallicity of the star. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.Figures 2 and 3 are available in electronic form at http://www.aanda.org

Britavskiy, N. E.; Andrievsky, S. M.; Tsymbal, V. V.; Korotin, S. A.; Martin, P.; Andrievska, A. S.

2012-06-01

80

Systems With Variable Composition: The Chemical Potential Chemistry CHEM 213W  

E-print Network

or 2) by changing the composition through chemical reaction. Nonetheless, as far as state functions, number of moles, etc.) and where µi,op is called the opposing chemical potential (and is analogous to the opposing pres- sure). For reversible processes, the opposing chemical potential equals the chemical

Ronis, David M.

81

Chemical Composition of Organic Aerosol Particles over the Remote Ocean  

NASA Astrophysics Data System (ADS)

Marine aerosol particles play an important role in Earth's radiative balance, yet the composition of the organic fraction of these important particles remains largely unconstrained. The composition of marine aerosol particles was measured in remote marine regions on board the R/V Atlantis during the CalNex 2010 campaign in May and June 2010, on board the R/V Point Sur during the E-PEACE campaign in July 2011, and on board the R/V Ronald Brown during the WACS campaign in August 2012. To understand the factors that control this composition, we compared the organic components of these particles to models of primary marine aerosol - i.e. those generated from bubbled and atomized seawater. The organic chemical composition was characterized by Fourier Transform Infrared (FTIR) spectroscopy to determine the functional group composition and high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) to identify characteristic mass fragments. Cluster analysis of FTIR organic spectra was used to identify different spectral signatures associated with location, seawater composition, and ambient conditions. Typical submicron organic mass (OM) concentrations were less than 0.80 ?g m-3. The overall organic compositions of marine aerosol particles and generated seawater models were similar, with large fractions of organic hydroxyl functional groups in each. One cluster of FTIR spectra from the eastern Pacific showed the highest fraction of hydroxyl functional groups (77%) occurred during periods of high chlorophyll concentrations and high wind speeds (more than 10 m s-1). Detailed spectral comparisons revealed unique minor features that may be driven both by meteorology and regional differences in seawater composition for these and past studies.

Russell, L. M.; Frossard, A. A.; Keene, W. C.; Kieber, D. J.; Quinn, P.; Bates, T. S.

2012-12-01

82

Use of Cullet of Different Chemical Compositions in Foam Glass Production  

Microsoft Academic Search

The results of studying the possibility of using cullet of different chemical compositions accumulated at dumping grounds for foam glass production are described. It is established that sodium silicate introduced into cullet in the form of water glass partly destroys milled cullet and homogenizes the chemical composition of the batch and its most significant technological properties. Due to the chemical

K. K. Éidukyavichus; V. R. Matseikene; V. V. Balkyavichus; A. A. Shpokauskas; A. A. Laukaitis; L. Yu. Kunskaite

2004-01-01

83

Switchgrass biomass and chemical composition for biofuel in eastern Canada  

SciTech Connect

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

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

1999-08-01

84

Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites  

Microsoft Academic Search

Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated

Kmetz

1992-01-01

85

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

86

Chemical composition of precipitation and its sources in Hangzhou, China.  

PubMed

To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH??, Ca²?, Mg²?, Na?, K?, SO?²?, NO??, F?, and Cl?). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO?²?/NO?? ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO?²?, Ca²?, and Mg²? and 33.7% of K? were of non-sea origins, while all Na? and Cl? and 66.3% of K? originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources. PMID:21380918

Xu, Hong; Bi, Xiao-Hui; Feng, Yin-Chang; Lin, Feng-Mei; Jiao, Li; Hong, Sheng-Mao; Liu, Wen-Gao; Zhang, Xiao-Yong

2011-12-01

87

Epicuticular Wax Crystals of Wollemia nobilis: Morphology and Chemical Composition  

PubMed Central

Background and Aims The morphology of the epicuticular leaf waxes of Wollemia nobilis (Araucariaceae) was studied with special emphasis on the relationship between the microstructure of epicuticular wax crystals and their chemical composition. Wollemia nobilis is a unique coniferous tree of the family Araucariaceae and is of very high scientific value as it is the sole living representative of an ancient genus, which until 1994 was known only from fossils. Methods Scanning electron microscopy (SEM), gas chromatography (GC) combined with mass spectrometry (GC–MS) and nuclear magnetic resonance spectroscopy (NMR) were used for characterizing the morphology and the chemical structure of the epicuticular wax layer of W. nobilis needles. Key Results The main component of the leaf epicuticular wax of W. nobilis is nonacosan-10-ol. This secondary alcohol together with nonacosane diols is responsible for the tubular habit of the epicuticular wax crystals. Scanning electron micrographs revealed differences in the fine structure of adaxial and abaxial leaf surfaces that could be explained by gas chromatographic studies after selective mechanical removal of the waxes. Conclusions SEM investigations established the tubular crystalline microstructure of the epicuticular wax of W. nobilis leaves. GC–MS and NMR experiments showed that nonacosan-10-ol is the major constituent of the epicuticular wax of W. nobilis leaves. PMID:17611192

Dragota, Simona; Riederer, Markus

2007-01-01

88

Chemical Mechanical Planarization- Chemical  

NSDL National Science Digital Library

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

2012-12-07

89

Evolutionary changes in the chemical composition of /upsilon/Sgr  

SciTech Connect

An analysis is made of the chemical composition of the atmosphere of the bright component of the close binary system /upsilon/ Sgr, which lost a hydrogen envelope as a result of mass transfer. Besides the deficit of hydrogen, an excess of helium, and changes in the abundances of carbon, nitrogen, and oxygen due to hydrogen burning into helium through the CNO cycle and partly of helium into carbon through the triple /alpha/ process, excesses in the abundances of many other elements are found. The abundances of the elements from hydrogen to nickel are similar to those obtained for a number of other stars with extremely large helium excesses, although in the case of /upsilon/ Sgr there are some differences due to its binary nature. For elements with Z > 30 there is a tendency for the excess to increase with increasing atomic number, similar to what is observed for Am stars.

Leushin, V.V.; Topil'skaya, G.P.

1988-11-01

90

Rapid fabrication of ceramic composite tubes using chemical vapor infiltration  

SciTech Connect

Ceramic composite tubes can be fabricated with silicon carbide matrix and Nicalon fiber reinforcement using forced flow-thermal gradient chemical vapor infiltration (FCVI). The process model GTCVI is used to design the equipment configuration and to identify conditions for rapid, uniform densification. The initial injector and mandrel design produced radial and longitudinal temperature gradients too large for uniform densification. Improved designs have been evaluated with the model. The most favorable approach utilizes a free-standing preform and an insulated water-cooled gas injector. Selected process conditions are based on the temperature limit of the fiber, matrix stoichiometry and reagent utilization efficiency. Model runs for a tube 12 inches long, 4 inches OD and 1/4 inch wall thickness show uniform densification in approximately 15 hours.

Starr, T.L.; Chiang, D. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering; Besmann, T.M.; Stinton, D.P.; McLaughlin, J.C.; Matlin, W.M. [Oak Ridge National Lab., TN (United States)

1996-06-01

91

Chemical composition and biological activity of Salvia verbenaca essential oil.  

PubMed

Salvia verbenaca L. (syn. S. minore) is a perennial herb known in the traditional medicine of Sicily as "spaccapetri" and is used to resolve cases of kidney stones, chewing the fresh leaves or in decoction. The chemical composition of the essential oil obtained from aerial parts of S. verbenaca collected in Piano Battaglia (Sicily) on July 2009, was analyzed by GC and GC-MS. The oil was strongly characterized by fatty acids (39.5%) and carbonylic compounds (21.2%), with hexadecanoic acid (23.1%), (Z)-9-octadecenoic acid (11.1%) and benzaldehyde (7.3%) as the main constituents. The in vitro activity of the essential oil against some microorganisms in comparison with chloramphenicol by the broth dilution method was determined. The oil exhibited a good activity as inhibitor of growth of Gram + bacteria. PMID:21834249

Canzoneri, Marisa; Bruno, Maurizio; Rosselli, Sergio; Russo, Alessandra; Cardile, Venera; Formisano, Carmen; Rigano, Daniela; Senatore, Felice

2011-07-01

92

[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

93

Chemical composition of human and canine fascia lata.  

PubMed

The fascial system is an integral part of the musculoskeletal system. It is a three-dimensional network of connective tissue spreading ubiquitously throughout the body, surrounding muscles, bones, internal organs, nerves, vessels, and other structures. The basic biophysical properties of the fascial system are determined by its structure and chemical composition. This study aimed to determine the elemental composition of pathologically unchanged fascia lata of the thigh, collected during autopsies on humans and dogs. The wide spectrum of elements analysed included both macro and micro elements. The analyses were conducted using scanning electron microscopy with X-ray microanalysis (SEM-EDS). Concentrations of the following macro and micro elements were determined: C, N, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Fe Co, Ni, Cu, and Zn. The obtained results showed significant differences between human and canine fascia lata regarding the content of most of the examined elements (p < 0.05), except for N. These data may in future provide a starting point for the establishment of reference values for the content of various elements in normal fascial tissue and may also serve to verify the usefulness of experimental animal material as a substitute for human tissue. PMID:23173122

Maksymowicz, Krzysztof; Marycz, Krzysztof; Szotek, Sylwia; Kali?ski, Krzysztof; Serwa, Ewa; ?ukomski, Robert; Czoga?a, Joanna

2012-01-01

94

Dictyostelium Cells Migrate Similarly on Surfaces of Varying Chemical Composition  

PubMed Central

During cell migration, cell-substrate binding is required for pseudopod anchoring to move the cell forward, yet the interactions with the substrate must be sufficiently weak to allow parts of the cell to de-adhere in a controlled manner during typical protrusion/retraction cycles. Mammalian cells actively control cell-substrate binding and respond to extracellular conditions with localized integrin-containing focal adhesions mediating mechanotransduction. We asked whether mechanotransduction also occurs during non-integrin mediated migration by examining the motion of the social amoeba Dictyostelium discoideum, which is thought to bind non-specifically to surfaces. We discovered that Dictyostelium cells are able to regulate forces generated by the actomyosin cortex to maintain optimal cell-surface contact area and adhesion on surfaces of various chemical composition and that individual cells migrate with similar speed and contact area on the different surfaces. In contrast, during collective migration, as observed in wound healing and metastasis, the balance between surface forces and protrusive forces is altered. We found that Dictyostelium collective migration dynamics are strongly affected when cells are plated on different surfaces. These results suggest that the presence of cell-cell contacts, which appear as Dictyostelium cells enter development, alter the mechanism cells use to migrate on surfaces of varying composition. PMID:24516575

Wang, Chenlu; Losert, Wolfgang; Parent, Carole A.

2014-01-01

95

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

Microsoft Academic Search

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

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

96

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

Microsoft Academic Search

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,

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

2010-01-01

97

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...

98

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

99

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

100

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

101

Chemical Composition of Bottled Water in Saudi Arabia  

Microsoft Academic Search

Fourteen domestic and seven imported bottled water brands were analysed in Saudi Arabia for various physico-chemical water quality parameters. The results of the analysis were compared with the drinking water standards set by Saudi Arabia and World Health Organization. The levels of different physico-chemical parameters like TDS, Ca, Mg, Na, K, NO3, Cl and SO4 of all local and imported

Abdulrahman I. Alabdula'aly; Mujahid A. Khan

1999-01-01

102

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

Microsoft Academic Search

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

T. P. DeFelice

1998-01-01

103

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

104

particular incorporation improve interface biomaterial?bone chemical composition phosphocalcic ceramic (Ca P) generate covalent chemical bonds bone contacts whose cells proliferate multiply inside biomaterial 14  

EPA Pesticide Factsheets

Search instead for particular incorporation improve interface biomaterial?bone chemical composition phosphocalcic ceramic (Ca P) generate covalent chemical bonds bone contacts whose cells proliferate multiply inside biomaterial 14 ?

105

Carbonate cements in sandstones - mineralogy and chemical composition  

SciTech Connect

The chemical compositions of carbonate cements in sandstones were analyzed with an energy dispersive analyzer (KEVEX) and a scanning electron microscope in order to provide a baseline data base for one of the most common authigenic phases in sandstones. A total of 205 spectra was analyzed with respect to mineral standards using ZAF corrections. These spectra were acquired from 35 Cambrian to Cretaceous carbonate-cemented sandstones from our sedimentary rock collections. Only 19% of the analyses were pure calcite (i.e., no Mg, Mn, or Fe were detected). Impure calcites accounted for 54% of the analyses, and dolomites and ankerites accounted for 27%. When the calcites were treated as a single group, the distribution of the components was as follows: calcite 91.6-100%; magnesite, 0-8.4%; rhodochrosite, 0-2.3%;p and siderite, 0-4%. The dolomites and ankerites showed a larger range: calcite, 47.8-60.6%; magnesite, 20-52.2%; rhodochrosite, 0-12%; and siderite, 0-28.6%. The values of the calcite component in the dolomites that were significantly higher than 50% probably resulted from the beam (spot mode) encountering dolomite plus some calcite. In most cases, the calcite component was nearly 50%. Many of these compositions displayed a large variation within a sample, even at the micron-level scale. A series of closely spaced analyses - all within an area 200 x 100 ..mu..m - from a sample rich in dolomite and/or ankeite ranged between 20 and 43% magnesite and 6 and 29% siderite. The calcites normally only ranged a few percent for each component in analyses that were spaced at a similar scale.

Slow, E.S.; Anderhalt, R.

1985-02-01

106

Chemical composition and origin of nebulae around Luminous Blue Variables  

E-print Network

We use the analysis of the heavy element abundances (C, N, O, S) in circumstellar nebulae around Luminous Blue Variables to infer the evolutionary phase in which the material has been ejected. (1) We discuss the different effects that may have changed the gas composition of the nebula since it was ejected (2) We calculate the expected abundance changes at the stellar surface due to envelope convection in the red supergiant phase. If the observed LBV nebulae are ejected during the RSG phase, the abundances of the LBV nebulae require a significantly smaller amount of mass to be lost than assumed in evolutionary models. (3) We calculate the changes in the surface composition during the main sequence phase by rotation induced mixing. If the nebulae are ejected at the end of the MS-phase, the abundances in LBV nebulae are compatible with mixing times between 5 x 10^6 and 1 x 10^7 years. The existence of ON stars supports this scenario. (4) The predicted He/H ratio in the nebulae are significantly smaller than the current observed photospheric values of their central stars. Combining various arguments we show that the LBV nebulae are ejected during the blue SG phase and that the stars have not gone through a RSG phase. The chemical enhancements are due to rotation induced mixing, and the ejection is possibly triggered by near-critical rotation. During the ejection, the outflow was optically thick, which resulted in a large effective radius and a low effective temperature. This also explains the observed properties of LBV dust.

Henny J. G. L. M. Lamers; Antonella Nota; Nino Panagia; Linda J. Smith; Norbert Langer

2001-03-28

107

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

108

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

109

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

110

Chemical composition and antigenotoxic properties of Lippia alba essential oils  

PubMed Central

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-?-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds. PMID:21931523

Lopez, Molkary Andrea; Stashenko, Elena E.; Fuentes, Jorge Luis

2011-01-01

111

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

PubMed

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

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

2013-01-01

112

Chemical Composition and Antimicrobial Properties of Piper ovatum Vahl.  

PubMed

The chemical composition of the essential oil obtained from the leaves of Piperovatum Vahl by hydrodistillation was analyzed by GC-MS. The main constituents found were delta-amorphene (16.5 %), cis-muurola-4(14),5-diene (14.29 %) and gamma-muurolene(13.26%). The crude extracts and isolated compounds were screened for their antimicrobial activity. Hydroalcoholic extracts of different parts of Piper ovatum Vahl, essential oil andamides isolated from leaves were tested against Gram-positive and Gram-negative bacteria and Candida species. All extracts and amides were active against Bacillus subtilis andCandida tropicalis, including clinical strains. Essential oil was active against C. tropicalis.These amides showed an inhibitory effect on the adherence of C. tropicalis ATCC 28707 on cover glasses at 10 microg/mL, but did not show morphological alterations at the tested concentrations. Amides were identified as piperovatine and piperlonguminine, and showed MIC values of 15.6 and 31.2 microg/mL to B. subtilis and 3.9 microg/mL to C. tropicalis, and low toxic effects to Vero cells and macrophages. PMID:19325517

Silva, Daniel Rodrigues; Endo, Eliana Harue; Filho, Benedito Prado Dias; Nakamura, Celso Vataru; Svidzinski, Terezinha Inez Estivaleti; de Souza, Amanda; Young, Maria Claudia M; Ueda-Nakamura, Tânia; Cortez, Diógenes Aparício Garcia

2009-01-01

113

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

PubMed

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

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

1998-12-01

114

The chemical composition of the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

The Small Magellanic Cloud is a close, irregular galaxy that has experienced a complex star formation history due to the strong interactions occurred both with the Large Magellanic Cloud and the Galaxy. Despite its importance, the chemical composition of its stellar populations older than ˜ 1-2 Gyr is still poorly investigated. I present the first results of a spectroscopic survey of ˜ 200 Small Magellanic Cloud giant stars performed with FLAMES@VLT. The derived metallicity distribution peaks at [Fe/H] ˜ -0.9/-1.0 dex, with a secondary peak at [Fe/H] ˜ -0.6 dex. All these stars show [\\alpha/Fe] abundance ratios that are solar or mildly enhanced (˜ +0.1 dex). Also, three metal-poor stars (with [Fe/H] ˜ -2.5 dex and enhanced [\\alpha/Fe] ratios compatible with those of the Galactic Halo) have been detected in the outskirts of the SMC: These giants are the most metal-poor stars discovered so far in the Magellanic Clouds. Based on observations obtained at Paranal ESO Observatory with the FLAMES facility.

Mucciarelli, A.

2014-01-01

115

Chemical composition of sediments from White Sea, Russian Arctic  

NASA Astrophysics Data System (ADS)

The White Sea, the only Russian inland sea, is located on the north of outlying districts of the European part of Russia, belongs to Arctic Ocean. Area of water of sea occupies about 90 tousend square kilometers. The sea can be divided into some general parts: neck, funnel, basin and 4 Bays: Dvina Bay, Kandalaksha Bay, Mezen Bay and Onega Bay. The purpose of this work was geochemical mapping of the surface sediments of this area. The main tasks were: compilation data base of element composition of the surface sediments, geochemical mapping of each element, research of the anormal concentration of elements on the surface. To detect the content of chemical elements several methods were used: atomic absorption spectrometry (P.P. Shirshov Institute of Oceanology); neutron activation analysis (Vernadsky Institute of Geochemistry and Analytical Chemistry), total and organic carbon analysis, photometric method to detection Si, Al, P (P.P. Shirshov Institute of Oceanology). Bulk composition is one of the fundamental characteristics of sediments and bottom deposites of modern basins. Coarse-grained sediments with portion of pelitic component <50% is spread on the shallow area (Kandalaksha Bay), in areas with high hydrodynamic activity of near-bottom water. Under the conditions of their low activity, fine-grained facies are common(>80%). Character of elements distribution correlates with facial distribution of sediments from White Sea. According to litologic description, bottom surface of Dvina Bay is practically everywhere covered by layer of fine-grained sand. In the border area between Dvina Bay and White Sea basin on terraced subwater slope aleurite politic silts are abundant. They tend to exhange down the slope to clay silts. In Onega Bay fractions of non-deposition are observed. They are characterized by wide spread of thin blanket poorgraded sediments, which are likely to be relic. Relief of Kandalakscha Bay bottom is presented as alternation of abyssal fosses (near 300 m) with silles and elevations (<20 m), and also numerous islands. Thus variety of sediment composition is observed here - from rules and gravels to fine-grained clay silts [1]. The map of distribution of chemical elements was created by using bulk composition data with the help of program ArcView. Mn distribution in sedimentation mass is largely determed by influence of redox diagenesis. Reactive form of Mn dominates over less moving, litogenic form in sedimation mass of White Sea. Litogenic form remains in sediment, reactive form moves into silt near-bottom water, resulting Mn migration both in sediment and near-bottom layer of marine water. Mn oxidizes on the contact with oxygen of marine water and alters into insoluble form MnO2, causing Mn enrichment of surface layer of sediments. Highly movable silt deposit MnO2 and enriched by Mn suspension are moved by underflow and accumulate in bottom depressions and in central part of the sea, which is quite wide from both places of original sedimentation and run off sources [2]. Thus, the interrelation between granulometric composition of sediment and materials concentration can be shown by the example of Mn. Local conditions, leading to accumulation of clastic components, are: 1. Rise of content in sand owning to separation of heavy minerals 2. Rise of content in surface, mainly sandy clay sediments owning to presence of concretions 3. Rise of content in lower bunches roof owning to diagenetic contraction. Authors thank academic Lisitsyn for encourage, Andrey Apletalin for valuable help, and everybody, who helped in field and laboratory research of the White sea sediments. Work was being done under the auspices of Russian foundation of basic research (grants 09-05-10081, 09-05-00658 and 08-05-00860), RSA presidiums program of 17 fundamental researches (project 17.1). References: 1.Kuzmina T., Lein A., Lutchsheva L., Murdmaa I., Novigatsky A., Shevchenko V. Chemical composition of White Sea's sediments // Litology and mineral deposits . 2009. - ? 2. - P 115-132. 2.Nevessky E., Medvedev V. , Kalin

Gamza, Olga; Shevchenko, Vladimir; Novigatsky, Aleksandr

2010-05-01

116

Chemical Composition of Soils of Cass, Dickens, Falls, Hardeman, Polk, Scurry, and Wheeler Counties.  

E-print Network

LIBRARY, A & M COLLEGE. CAMPUS. A29-1239-6M-LIB6 TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION. BRAZOS COUNTY. TEXAS BULLETIN NO. 581 JANUARY 1940 DIVISION OF CHEMISTRY Chemical Composition Of The Soils... .................... ... Relation of chemical analysis to production .'. 15 ............................ Average composition of the soils studied 15 .................................... Fertilizers for the soils studied 19 Use of lime...

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

1940-01-01

117

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, Canada V2N 4Z9, e-mail: arocenaj@unbc.ca; and 2Department of Soil Science, University of British Columbia., Glowa, K. R., Massicotte, H. B. and Lavkulich, L. 1999. Chemical and mineral composition of ectomycorrhi

Massicotte, Hugues

118

Predicting the chemical composition of fibre and core fraction of hemp ( Cannabis sativa L.)  

Microsoft Academic Search

Summary  Fibre formation in hemp (Cannabis sativa L.) is a dynamic process. In order to follow this process, the chemical composition of the hemp stem was studied during plant development using the acid and neutral detergent fibre and lignin methods. Additionally, near infra-red spectroscopy was carried out. To predict the chemical composition of the stem samples partial least square (PLS) analysis

Marcel A. J. Toonen; Chris Maliepaard; Theo H. Reijmers; Hilko van der Voet; H. Dick Mastebroek; Hetty C. van den Broeck; Michel J. M. Ebskamp; Waltraud Kessler; Rudolf W. Kessler

2004-01-01

119

Changes in chemical composition in male turkeys during growth.  

PubMed

In growing animals, requirements for many nutrients (and energy) are determined by the retention of these nutrients. During growth, this retention changes in an absolute way and also between nutrients and energy, resulting in changing nutrient requirements. The objective of this study was to describe the changes in chemical composition in male growing turkeys. The serial slaughter technique was used to determine the composition of amino acids, lipid, ash, and water in feather-free body (FFB) and feathers in male turkeys offered feed ad libitum from 1 to 15 wk of age. Allometric relations were used to describe changes in body composition. The feather content in the body decreased from 6% at 1 wk of age to less than 3% at 15 wk of age. The water and protein content in FFB decreased with increasing FFB mass, with allometric scalars (b) of, respectively, 0.967 and 0.970, whereas the lipid content increased with increasing FFB mass (b = 1.388). The water, protein, and ash content in fat-free FFB was constant and represented, respectively, 71.6, 24.2, and 4.2% of the fat-free FFB mass. The amino acid content of FFB protein was relatively constant and only the Cys content decreased between 1 and 15 wk of age, whereas the Ile content increased. Feathers were mostly composed of protein, and the protein content did not change during growth. During growth, the Lys, Met, Trp, His, Tyr, Asp, and Glu contents in feather protein decreased, whereas the Cys, Val, and Ser contents increased. The contribution of feathers to whole-body amino acid retention ranged from 5% for His to 33% for Cys. On average, the weight gain of FFB contained 21.3% protein and 12.7% lipid, corresponding to an energy content of 10.1 kJ/g. The weight gain of feathers contained 87.4% protein, corresponding to an energy content of 20.4 kJ/g. The results of the present study can be used in a factorial approach to determine nutrient requirements in growing turkeys. PMID:21177445

Rivera-Torres, V; Noblet, J; van Milgen, J

2011-01-01

120

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

121

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

122

Chemical composition of ambient particulate matter and redox activity.  

PubMed

Exposure to ambient particulate matter (PM) has been associated with a number of adverse health effects. Increasing studies have suggested that such adverse health effects may derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. The study aimed to assess physical characteristics and chemical compositions of PM and to correlate the results to their redox activity. PM(2.5) (mass aerodynamic diameter < or =2.5 microm) and ultrafine particles (UFPs, mass media aerodynamic diameter <0.1 microm) were collected in an urban area, which had heavy traffic and represented ambient air pollution associated with vehicle exhaust. Background samples were collected in a rural area, with low traffic flow. Organic carbon (OC), elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), and metals were analyzed. The dithiothreitol activity assay was used to measure the redox activity of PM. Results showed that UFPs have higher concentrations of OC, EC, and PAHs than those of PM(2.5). Several metals, including Fe, Cu, Zn, Ti, Pb, and Mn, were detected. Among them, Cu had the highest concentrations, followed by Fe and Zn. Organic carbon constituted 22.8% to 59.7% of the content on the surface of PM(2.5) and UFPs. Our results showed higher redox activity on a per PM mass basis for UFPs as compared to PM(2.5). Linear multivariable regression analyses showed that redox activity highly correlated with PAH concentrations and organic compounds, and insignificantly correlated with EC and metals, except soluble Fe, which increased redox activity in particle suspension due to the presence of ROS. PMID:19902370

Jeng, Hueiwang Anna

2010-10-01

123

Chemical composition of phosphorites of the Phosphoria Formation  

USGS Publications Warehouse

The chemical composition, both major and minor constituents, of 60 samples of phosphorite from the Phosphoria Formation was determined. Major constituents of the average phosphorite are, by weight per cent: SiO2, 11??9; Al2O3, 1??7; Fe2O3,1??1; MgO, 0??3; CaO, 44??0; Na2O, 0??6; K2O, 0??5; total H2O, 2??2; H2O-, 0??6; TiO2, 0??1; P2O5, 30??5; CO2, 2??2; SO3, 1??8; F, 3??1; organic matter, 2??1; and oil, 0??2. Uranium averages 0??009 per cent. The phosphate mineral is basically apatite, Ca5(PO4)3F, with small but significant and variable substitutions-Na, Sr, U and Th for Ca, and CO3 and SO4 for PO4. Rare metals not associated with apatite are associated principally with the organic-matter component of the rocks. This group includes As, Ag, Cd, Cr, Cu, Mo, Ni, Sb, Se, V and Zn. Chromium is the most abundant, having a modal abundance of 0??1 per cent and a maximum concentration of 0??3 per cent. The average phosphorite is composed of approximately 80 per cent apatite, 10 per cent quartz, 5 per cent muscovite-illite, 2 per cent organic matter, 1 per cent dolomite-calcite, 1 per cent iron oxide, and 1 per cent other components. It is texturally a medium-grained pellet phosphorite. ?? 1966.

Gulbrandsen, R.A.

1966-01-01

124

The Chemical Composition of Local Group Dwarf Spheroidals  

E-print Network

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

Eline Tolstoy

2005-06-21

125

Adhesion at diamond-metal interfaces: a chemical composition perspective  

Microsoft Academic Search

Diamond films were chemically vapor deposited (CVD) on titanium, tungsten, molybdenum, copper and aluminum oxide substrates. In these studies, the interface formed between diamond and the substrate was exposed by mechanically deforming the metal substrate or diamond film to cause film delamination. The observed degree of adhesion for these interfaces can be ranked in the order: Ti » Al2O3 (thin

Scott S. Perry; Sean P. McGinnis; Gabor A. Somorjai

1995-01-01

126

Effect of Amine Activators on the Properties of Chemical Cured Dental Composites  

Microsoft Academic Search

The purpose of this study was to evaluate the reactivity and the effect of concentration of three tertiary amines upon the mechanical properties of a chemical curing dental composite. Chemical cured composite pastes were prepared by keeping peroxide concentration constant at 1 wt% (by weight of resin mixture) and by varying the amine\\/peroxide molar ratio from 0.25 to 1.5. Composite

Leny Mathew; Roy Joseph; V. Kalliyana Krishnan

1997-01-01

127

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

128

Chemical composition of the haze in Malaysia 2005  

NASA Astrophysics Data System (ADS)

A study of the chemical composition of the haze was conducted in two areas: Klang Valley and Malacca in Peninsular Malaysia, from July to September of 2005. The data is based on the reports of the air quality monitoring for particulate matter (PM10), pH of rainwater, anions (NO3-, SO42-, Cl-), cations (NH4+, Na2+, Ca2+, K+, Mg2+), heavy metals (Fe, Zn, Pb, Mn, Cu, Ni) and a meteorology parameter, the wind speed. The monthly concentrations of PM10 for the Klang Valley ranged from 35.90 to 104.46 ?g m-3 whilst in Malacca the concentration ranged from 35.80 to 54.30 ?g m-3 which was over the permitted level of 50 ?g m-3 for the time period of a month as stipulated by the Department of Environment Malaysia (DOE). The pH of rainwater collected in the Klang Valley ranged from 4.26 ± 0.12 to 5.45 ± 0.58, while in Malacca the pH varied from 4.35 ± 0.20 to 5.43 ± 0.12. The mean concentrations for NO3-, SO42-, Cl-, NH4+, Ca2+, Na2+, K+, Mg2+ for three months in the Klang Valley were 46.40 ± 11.16 ?eq L-1, 34.84 ± 9.82 ?eq L-1, 12.34 ± 4.13 ?eq L-1, 29.28 ± 11.02 ?eq L-1, 8.92 ± 0.88 ?eq L-1, 8.18 ± 1.00 ?eq L-1, 2.08 ± 0.34 ?eq L-1, 1.38 ± 0.24 ?eq L-1, respectively, whilst in Malacca, the mean concentrations were 24.46 ± 6.99 ?eq L-1, 28.4 ± 7.24 ?eq L-1, 27.32 ± 7.36 ?eq L-1, 30.92 ± 1.26 ?eq L-1, 4.10 ± 2.56 ?eq L-1, 21.44 ± 7.54 ?eq L-1, 3.18 ± 1.82 ?eq L-1 and 1.54 ± 1.66 ?eq L-1, respectively. These values were lower than the non haze period (January to March and April to June) except for the Cl- ion which recorded the highest anion in Malacca. However, the mean values were similar for the period from October to December. The mean concentrations of metals showed that Cu > Ni, whilst in Malacca, in descending order, were Fe > Zn > Cu > Mn > Pb > Ni.

Norela, S.; Saidah, M. S.; Mahmud, M.

2013-10-01

129

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

E-print Network

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

Douglas, Thomas A.

130

Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition  

Microsoft Academic Search

Sorption potential of waste short hemp fibers for Pb2+, Cd2+ and Zn2+ ions from aqueous media was explored. In order to assess the influence of hemp fiber chemical composition on their heavy metals sorption potential, lignin and hemicelluloses were removed selectively by chemical modification. The degree of fiber swelling and water retention value were determined in order to evaluate the

Biljana Pejic; Marija Vukcevic; Mirjana Kostic; Petar Skundric

2009-01-01

131

Fabrication of fiber-reinforced composites by chemical vapor infiltration  

SciTech Connect

A two-step forced chemical vapor infiltration process was developed that reduced infiltration times for 4.45 cm dia. by 1.27 cm thick Nicalon{sup +} fiber preforms by two thirds while maintaining final densities near 90 %. In the first stage of the process, micro-voids within fiber bundles in the cloth were uniformly infiltrated throughout the preform. In the second stage, the deposition rate was increased to more rapidly fill the macro-voids between bundles within the cloth and between layers of cloth. By varying the thermal gradient across the preform uniform infiltration rates were maintained and high final densities achieved.

Matlin, W.M. [Univ. of Tennessee, Knoxville, TN (United States); Stinton, D.P.; Besmann, T.M. [Oak Ridge National Lab., TN (United States)

1995-08-01

132

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

133

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

E-print Network

Context: The study of chemical abundance patterns in globular clusters is of key importance to constrain the different candidates for intra-cluster pollution of light elements. Aims: We aim at deriving accurate abundances for a large 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 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] = $-0.78\\pm0.07$ and $[\\alpha/{\\rm Fe}]=0.34\\pm0.03$ in...

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

2014-01-01

134

INTERACTION BETWEEN GAS DIFFUSION AND MULTISTABLE HETEROGENEOUS CHEMICAL KINETICS IN C=C COMPOSITE  

E-print Network

brakes are frequently made of carbon/carbon (C=C) compos- ites. To deposit the composite interphaseINTERACTION BETWEEN GAS DIFFUSION AND MULTISTABLE HETEROGENEOUS CHEMICAL KINETICS IN C=C COMPOSITE PROCESSING G#19;erard L. VIGNOLES Universit#19;e Bordeaux 1, Laboratoire des Composites ThermoStructuraux 3

Recanati, Catherine

135

Improved fiber-reinforced SiC composites fabricated by chemical vapor infiltration  

SciTech Connect

Fabrication of fiber-reinforced composites by a patented chemical vapor infiltration process has continued. Modifications to the process used for infiltration of unidirectional preforms resulted in more uniform matrix deposition throughout the preform and improved mechanical properties of the composites. Infiltration of improved cloth preforms containing more uniform porosity resulted in composites with fewer and smaller voids.

Stinton, D.P.; Caputo, A.J.; Lowden, R.A.; Besmann, T.M.

1986-01-01

136

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

137

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...

138

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...

139

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

NASA Astrophysics Data System (ADS)

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

DeFelice, T. P.

140

Chemical Composition and Temperature Fluctuations in M17  

NASA Astrophysics Data System (ADS)

We present echelle spectroscopy in the 3500 to 10300 Angstroms range for two positions of the galactic H ii region M17. The data have been obtained using the 2.1 m telescope at Observatorio Astronomico Nacional in San Pedro Martir, Baja California. We measure the intensities of 160 emission lines, in particular 36 permitted lines of C(+) , N(0) , N(+) , N(++) , O(0) , O(+) , Ne(0) , Si(0) , and Si(+) . We determine electron temperatures and densities using different line intensity ratios as well as abundances from collisionally excited lines for a large number of ions and elements. We derive the He(+) , C(++) and O(++) ionic abundances from recombination lines, these nebular values are almost independent of the temperature structure of the nebula. We determine accurate t(2) values by comparing the O(++) ionic abundance obtained from collisionally excited lines and recombination lines. A comparison of the chemical abundances of the Sun, M17, M8, and the Orion nebula is made. We present strong observational constraints based on abundance ratios and compare them with recent models of galactic chemical evolution.

Peimbert, M.; Esteban, C.; Torres-Peimbert, S.; Garcia-Rojas, J.

1999-05-01

141

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

142

Chemical Composition and Antifungal Activity of Essential Oil from Cymbopogon nardus (Citronella Grass)  

Microsoft Academic Search

The objective of this study was to elucidate the chemical composition of essential oil from Cymbo- pogon nardus (citronella oil) and its antifungal activity. Chemical composition of the citronella oil was determined by capillary gas chromatography (GC) and GC\\/ mass spectrometry. Major constituents of the oil were geraniol (35.7% of total volatiles), trans-citral (22.7%), cis-citral (14.2%), geranyl acetate (9.7%), citronellal

Kazuhiko NAKAHARA; Najeeb S. ALZOREKY; Tadashi YOSHIHASHI; T. T. NGUYEN

2003-01-01

143

Absolute parameters and chemical composition of the binary star OU Gem  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

144

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.

0002-11-30

145

Chemical composition, characterization, and differentiation of honey botanical and geographical origins.  

PubMed

Botanical and biographical origins of honey are an important issue in food quality and safety. This chapter focuses on use of chemical components to determine botanical and geographical origins of honey. The botanical and geographical origins of the nectar are related with the chemical composition of honey. Honey can originate from single and multiplant species. In general, the prices of honey from single plant species are much higher than those of common polyfloral honey because of consumer preferences. Single and multiple chemicals and components can well indicate the botanical and geographical origins of the honey. Marker chemicals and components include flavonoids, pollen, aroma compounds, oligosaccharides, trace elements, amino acids, and proteins. If multiple chemicals are used as markers, patterns of the chemicals are often used to detect the botanical and geographical origins of honey. Modern statistical software in combination with advanced analytical instrumentation provides high potential for the differentiation of the botanical and geographical origins of the honey. PMID:21504822

Wang, Jun; Li, Qing X

2011-01-01

146

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).

Fox, Chris

147

Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity  

USGS Publications Warehouse

The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomena or human-caused events. Chemical mixtures may also have ecological, industrial, geochemical, or toxicological effects. Chemical-mixture occurrences vary by analyte composition and concentration. Four related computer programs have been developed by the National Water-Quality Assessment Program of the U.S. Geological Survey for research of chemical-mixture compositions, occurrences, distributions, and possible toxicities. The compositions and occurrences are identified for the user-supplied data, and therefore the resultant counts are constrained by the user’s choices for the selection of chemicals, reporting limits for the analytical methods, spatial coverage, and time span for the data supplied. The distribution of chemical mixtures may be spatial, temporal, and (or) related to some other variable, such as chemical usage. Possible toxicities optionally are estimated from user-supplied benchmark data. The software for the analysis of chemical mixtures described in this report is designed to work with chemical-analysis data files retrieved from the U.S. Geological Survey National Water Information System but can also be used with appropriately formatted data from other sources. Installation and usage of the mixture software are documented. This mixture software was designed to function with minimal changes on a variety of computer-operating systems. To obtain the software described herein and other U.S. Geological Survey software, visit http://water.usgs.gov/software/.

Scott, Jonathon C.; Skach, Kenneth A.; Toccalino, Patricia L.

2013-01-01

148

Chemical sensor  

NASA Technical Reports Server (NTRS)

A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

Rauh, R. David (Inventor)

1990-01-01

149

Chemical microsensors  

NASA Astrophysics Data System (ADS)

Recent developments are discussed in the field of chemical microsensors that attempt to marry physical transducers based on microelectronic and optoelectronic technologies with thin films and coatings that serve as chemical transducers. Microelectronic silicon chemical sensors, acoustic wave sensors, microsensors based on optical fibers, and electrochemical microsensors are considered. Both technological achievements and problems that remain to be solved are addressed.

Hughes, R. C.; Ricco, A. J.; Butler, M. A.; Martin, S. J.

1991-10-01

150

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

151

Conical intersection seams in polyenes derived from their chemical composition  

SciTech Connect

The knowledge of conical intersection seams is important to predict and explain the outcome of ultrafast reactions in photochemistry and photobiology. They define the energetic low-lying reachable regions that allow for the ultrafast non-radiative transitions. In complex molecules it is not straightforward to locate them. We present a systematic approach to predict conical intersection seams in multifunctionalized polyenes and their sensitivity to substituent effects. Included are seams that facilitate the photoreaction of interest as well as seams that open competing loss channels. The method is based on the extended two-electron two-orbital method [A. Nenov and R. de Vivie-Riedle, J. Chem. Phys. 135, 034304 (2011)]. It allows to extract the low-lying regions for non-radiative transitions, which are then divided into small linear segments. Rules of thumb are introduced to find the support points for these segments, which are then used in a linear interpolation scheme for a first estimation of the intersection seams. Quantum chemical optimization of the linear interpolated structures yields the final energetic position. We demonstrate our method for the example of the electrocyclic isomerization of trifluoromethyl-pyrrolylfulgide.

Nenov, Artur; Vivie-Riedle, Regina de [Department Chemie, Ludwig-Maximilians-Univerisitaet, Muenchen Butenandtstr. 11, 81377 Muenchen (Germany)

2012-08-21

152

Chemical composition and larvicidal activity of Algerian Foeniculum vulgare seed essential oil  

Microsoft Academic Search

A laboratory study was conducted to determine the effect of three extraction parameters (soaking time, extraction time and the ratio of solid to liquid) on the yield and chemical composition of Foeniculum vulgare seeds essential oils. The bioactivity of the essential oil extracted for the optimum extraction parameters was assessed against Culex pipiens mosquito. F. vulgare essential oil composition included

Safia Zoubiri; Aoumeur Baaliouamer; Nabila Seba; Nesrine Chamouni

153

Survey of the chemical composition of 571 European bottled mineral waters  

Microsoft Academic Search

As part of the European TRACE project (Tracing Food commodities in Europe, VI FP, Contract N. 006942), this paper provides a wide-ranging survey of the chemical composition of 571 mineral waters bottled and marketed in 23 European countries, and discusses 39 compositional parameters (specific electric conductivity, pH, hardness, total alkalinity, ammonia, chloride, fluoride, nitrate, nitrite, sulphate, Ca, K, Mg, Na,

Daniela Bertoldi; Luana Bontempo; Roberto Larcher; Giorgio Nicolini; Susanne Voerkelius; Gesine D. Lorenz; Henriette Ueckermann; Heinz Froeschl; Malcolm J. Baxter; Jurian Hoogewerff; Paul Brereton

2011-01-01

154

Proximate Chemical Composition and Fatty Acids of Three Small Coastal Pelagic Species  

E-print Network

high level of 22:6w3, but in general the fatty acid profiles of the three species were similar and didProximate Chemical Composition and Fatty Acids of Three Small Coastal Pelagic Species MALCOLM B. HALE Introduction Information on the proximate chem- ical composition and fatty acid profiles

155

Influence of chemical composition of soils on the galanthamine content in Levcojum aestivum  

Microsoft Academic Search

The elemental composition of seven soils of the main geographical regions in Bulgaria for the growth of Leucojum aestivum L. was determined. It was found that a relationship exists between the galanthamine content of the plant and the chemical composition of the soil. These results indicate that galanthamine bio? synthesis could be controlled by the soil fertility level.

N. I. Gorinova; A. I. Atanassov; D. V. Stojanov; J. Tencheva

1993-01-01

156

Studies on the chemical compositions and anti nutrients of some lesser known Nigeria fruits  

Microsoft Academic Search

Fruit samples of Cola millenii, Strychnos innocua, Bombax glabra, Artocarpus heterophyllus, Parkia biglobosa and Gardenia erubescens were collected from various locations in Oyo and Osun States of Nigeria. The chemical compositions of these fruits were analyzed with a view to evaluating their levels of nutrient and anti-nutrients. The nutrients compositions of the fruits showed that the amount of crude fat

M. O. Bello; O. S. Falade; S. R. A. Adewusi

157

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

158

[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

159

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

160

Influence of various chemical treatments on the composition and structure of hemp fibres  

Microsoft Academic Search

The impact of several chemical treatments, including NaOH, polyethyleneimine, ethylenediaminetetraacetic acid, Ca(OH)2 and CaCl2 onto the composition and structure of hemp fibres was evaluated using differential thermal analysis, scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Comparison of results obtained with the last two techniques allows us to quantify the impact of the chemical treatments onto the crystallinity

Marianne Le Troedec; David Sedan; Claire Peyratout; Jean Pierre Bonnet; Agnès Smith; René Guinebretiere; Vincent Gloaguen; Pierre Krausz

2008-01-01

161

Chemical Composition and Biological Evaluation of the Essential Oil of Commiphora opobalsamum L  

Microsoft Academic Search

The chemical composition of three essential oil samples (stored aerial parts, fresh aerial parts, and fresh flowering tops) of Commiphora opobalsamum L., obtained by hydrodistillation, was determined using GC-MS analysis. The identified constituents represented 69.5 to 84.4 percent of the total chemical compounds of the three samples. The major components were ?-cadinol in the stored aerial parts, ?-calacorene in the

Shaza M. Al-Massarany; Fawkeya A. Abbas; Betul Demirci; Kemal H. C. Baser; Shabana I. Khan; Adnan J. Al-Rehaily; Jaber S. Mossa; Ehab A. Abourashed

2008-01-01

162

Drop size-dependent chemical composition in clouds and fogs  

Microsoft Academic Search

Cloud drop composition can be size-dependent. Size-dependent drop composition is important because it impacts the fate of some atmospheric species. Two new cloud water collectors were developed to provide improved resolution of drop size-dependent composition. Both collectors are active, multi-stage, rectangular jet cascade impactors designed to separate drops into three or more fractions across the expected drop size spectrum. The

Katharine Foster Moore

2002-01-01

163

Structure and chemical composition of the dentin-enamel junction analyzed by Confocal Raman Microscopy  

NASA Astrophysics Data System (ADS)

The structure and chemical composition of the human dentin-enamel junction (DEJ) was studied using confocal Raman microscopy - a chemical imaging technique. Slices of non-fixed, sound teeth were prepared with an Isomet diamond saw and scanned with Witec Alpha300R system. The combination of different characteristics peaks of phosphate, carbonate and organic matrix (respectively 960, 1072 and 1545 cm-1), generates images representing the chemical composition of the DEJ area. Images are also calculated using peak ratios enabling precise determination of the chemical composition across the DEJ. Then, with two characterized peaks, different pictures are calculated to show the ratio of two components. The images of the spatial distribution of mineral phosphate (960cm-1) to organic matrix (1545 cm-1) ratios, mineral carbonates (1072cm-1) to mineral phosphate ratios; and mineral carbonates to organic matrix ratios were reconstructed. Cross sectional and calculated graphic profile show the variations of the different chemical component ratios through the enamel and the dentin. Phosphate to organic ratio shows an accumulation of organic material under the enamel surface. The cross sectional profile of these pictures shows a high phosphate content compared to enamel in the vicinity of the DEJ. The Confocal Raman imaging technique can be used to further provide full chemical imaging of tooth, particularly of the whole DEJ and to study enamel and dentin decay.

Desoutter, A.; Salehi, H.; Slimani, A.; Marquet, P.; Jacquot, B.; Tassery, H.; Cuisinier, F. J. G.

2014-02-01

164

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

165

Algorithm reliability of remote optical analysis of the chemical composition of mature lunar rock.  

NASA Astrophysics Data System (ADS)

The optical diagram of albedo ?(0.62 ?m) vs. the color-index C1(0.62/0.38 ?m) of the lunar surface and the chemical composition corresponding to it (FeO+TiO2)-TiO2 are used to extract zones occupying 18 out of the 23 species of magmatic lunar rocks, appearing in the classification developed by Bogatikov et al. (1985). Using the chemical compositions of nearly 920 samples of lunar rocks, graphical and analytic representations are obtained of the chemical components of separate rock species, making it possible to estimate from the optical parameters of ? and C1 of mature rocks their composition, representing six basic chemical oxides: SiO2, TiO2, Al2O3, FeO, MgO, and CaO. The reliability of this algorithm was analyzed by calculating the shape of lunar rocks and their chemical composition from the original contents of FeO and TiO2 in the catalog of rock samples mentioned. The algorithm reliability is found to be satisfactory for the overwhelming majority of rock species.

Evsyukov, N. N.

1994-06-01

166

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

167

Nextel{trademark}/SiC composites fabricated using forced chemical vapor infiltration  

SciTech Connect

Oxide fiber-reinforced silicon carbide matrix composites were fabricated employing the forced-flow, thermal gradient chemical vapor infiltration (FCVI) process. Composites using Nextel{sup TM} fibers of varying composition were prepared to investigate the effectiveness of each Nextel{sup TM} fiber as a reinforcement for the given matrix. A carbon interface coating was used for the baseline materials, however, alternate interlayers with improved oxidation resistance were also explored Room-temperature flexure strengths of as-fabricated composites and specimens heated in air at 1273 K were measured and compared to results for other SiC-matrix composites.

Weaver, B.L. [3M Co., St. Paul, MN (United States); Lowden, R.A.; McLaughlin, J.C.; Stinton, D.P.; Besmann, T.M.; Schwarz, O.J. [Oak Ridge National Lab., TN (United States)

1993-06-01

168

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

169

Chemical sensors  

DOEpatents

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

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

1991-01-01

170

Chemical sensors  

DOEpatents

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

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

1991-07-02

171

Investigation of the chemical composition of meteorites by an activation method using a microtron  

NASA Astrophysics Data System (ADS)

The feasibility of using bremsstrahlung and photoneutrons from a microtron to measure the chemical composition of stony and iron meteorites is demonstrated. Conditions are established for the activation determination of approximately 20 elements in meteorite samples without their destruction. The optimal geometry and mode of irradiation are established; the contribution of competing reactions is calculated; and the limits and errors of the measurements are assessed. The chemical composition of the following meteorites was determined: the chondrites Zhovtnevyi Khutor (H5), Tsarev (L5), Kunashak (L5), Allende (CV3); the achondrites Norton County (Au) and Chervonyi Kut (Eu); and the iron meteorite Sikhote-Alin.

Kolesov, G. M.; Ernandes, A.

172

Chemical peels.  

PubMed

Chemical peels are a method of resurfacing with a long-standing history of safety in the treatment of various skin conditions. This article reviews the classification of different chemical agents based on their depth of injury. The level of injury facilitates cell turnover, epidermal thickening, skin lightening, and new collagen formation. Preprocedural, periprocedural, and postprocedural skin care are briefly discussed. To select the appropriate chemical peel, the provider should evaluate the patient's expectations, medical history, skin type, and possible complications to determine the best chemical peel to achieve the desired results. Patients with Fitzpatrick skin types IV to VI have increased risk of dyspigmentation, hypertrophic, and keloid scarring. These individuals respond well to superficial and medium-depth chemical peels. Advances in the use of combination peels allow greater options for skin rejuvenation with less risk of complications. PMID:24488634

Jackson, Adrianna

2014-02-01

173

Chemical threats.  

PubMed

The use of chemical agents as military weapons has been recognized for many centuries but reached the most feared and publicized level during World War I. Considerable political effort has been exercised in the twentieth century to restrict military strategies with chemicals. However, considerable concern currently exists that chemical weapons may be used as agents in civilian terrorism. The distribution of acetaminophen tablets contaminated with potassium cyanide and the release of sarin in the Tokyo sub-way system show that larger-scale deployment of chemical agents can be a reality. This reality makes it necessary for civilian disaster-planning strategies to incorporate an understanding of chemical agents, their effects, and the necessary treatment. PMID:16781273

Fry, Donald E

2006-06-01

174

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

E-print Network

can be a useful diagnostic for investigations of the chemistry of chemical vapor deposition CVD are given for atmospheric-pressure radio-frequency plasma CVD of diamond, corresponding to experiments used to investigate the chemistry of a wide range of chemical vapor deposition CVD processes. Systems

Swihart, Mark T.

175

MINEQL-EIR. Chemical Equilibrium Composition of Aqueous Systems  

SciTech Connect

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

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

1986-11-21

176

Chemical strategies for template syntheses of composite micro- and nanostructures  

Microsoft Academic Search

The template method for preparing nanomaterials entails synthesis of monodisperse tubular and fibrillar nanostructures within the pores of a membrane or other nanoporous solid. Nanostructured materials of this type constitute one of the most important frontiers in materials science, and composite nanomaterials have been of particular recent interest. While the template method has been used to prepare segmented nanowires, where

Veronica M. Cepak; John C. Hulteen; Guangli Che; Kshama B. Jirage; Brinda B. Lakshmi; Ellen R. Fisher; Charles R. Martin; Hiroshi Yoneyama

1997-01-01

177

Chemical-garden formation, morphology, and composition. I. Effect of the nature of the cations.  

PubMed

We have grown chemical gardens in different sodium silicate solutions from several metal-ion salts--calcium chloride, manganese chloride, cobalt chloride, and nickel sulfate--with cations from period 4 of the periodic table. We have studied their formation process using photography, examined the morphologies produced using scanning electron microscopy (SEM), and analyzed chemical compositions using X-ray powder diffraction (XRD) and energy dispersive X-ray analysis (EDX) to understand better the physical and chemical processes involved in the chemical-garden reaction. We have identified different growth regimes in these salts that are dependent on the concentration of silicate solution and the nature of the cations involved. PMID:21391635

Cartwright, Julyan H E; Escribano, Bruno; Sainz-Daz, C Ignacio

2011-04-01

178

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

179

Chemical composition of the essential oil of Feronia elephantum Correa.  

PubMed

The essential oil composition of Feronia elephantum Correa (family: Rutaceae) was examined by capillary gas chromatography (GC) and gas chromatography-mass spectroscopy (GC-MS). The analysis revealed the presence of 24 constituents, of which 18 constituents were identified. Trans-anethole (57.73%) and methyl chavicol (37.48%) were the major compounds, while cis-anethole, p-anisaldehyde, (E)-jasmone, methyl eugenol, ?-caryophyllene, linalool and (E)-methyl isoeugenol were also present as the minor constituents. PMID:21104525

Pande, Chitra; Tewari, Geeta; Singh, Charu; Singh, Shalini; Padalia, R C

2010-11-01

180

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

181

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

182

An Estimate of the Chemical Composition of Titan's Lakes  

NASA Astrophysics Data System (ADS)

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 (C2H6) (~76%-79%), propane (C3H8) (~7%-8%), methane (CH4) (~5%-10%), hydrogen cyanide (HCN) (~2%-3%), butene (C4H8) (~1%), butane (C4H10) (~1%), and acetylene (C2H2) (~1%). 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; Mousis, Olivier; Lunine, Jonathan I.; Lavvas, Panayotis; Vuitton, Véronique

2009-12-01

183

Chemical composition of fine particles in the Tennessee Valley region.  

PubMed

Fine particles in the atmosphere have elicited new national ambient air quality standards (NAAQS) because of their potential role in health effects and visibility-reducing haze. Since April 1997, Tennessee Valley Authority (TVA) has measured fine particles (PM2.5) in the Tennessee Valley region using prototype Federal Reference Method (FRM) samplers, and results indicate that the new NAAQS annual standard will be difficult to meet in this region. The composition of many of these fine particle samples has been determined using analytical methods for elements, soluble ions, and organic and elemental carbon. The results indicate that about one-third of the measured mass is SO4(-2), one-third is organic aerosol, and the remainder is other materials. The fraction of SO4(-2) is highest at rural sites and during summer conditions, with greater proportions of organic aerosol in urban areas throughout the year. Additional measurements of fine particle mass and composition have been made to obtain the short-term variability of fine mass as it pertains to human exposure. Measurements to account for semi-volatile constituents of fine mass (nitrates, semi-volatile organics) indicate that the FRM may significantly under-measure organic constituents. The potentially controllable anthropogenic fraction of organic aerosols is still largely unknown. PMID:11002593

Tanner, R L; Parkhurst, W J

2000-08-01

184

Chemical composition and origin of nebulae around Luminous Blue Variables  

E-print Network

We use the analysis of the heavy element abundances (C, N, O, S) in circumstellar nebulae around Luminous Blue Variables to infer the evolutionary phase in which the material has been ejected. (1) We discuss the different effects that may have changed the gas composition of the nebula since it was ejected (2) We calculate the expected abundance changes at the stellar surface due to envelope convection in the red supergiant phase. If the observed LBV nebulae are ejected during the RSG phase, the abundances of the LBV nebulae require a significantly smaller amount of mass to be lost than assumed in evolutionary models. (3) We calculate the changes in the surface composition during the main sequence phase by rotation induced mixing. If the nebulae are ejected at the end of the MS-phase, the abundances in LBV nebulae are compatible with mixing times between 5 x 10^6 and 1 x 10^7 years. The existence of ON stars supports this scenario. (4) The predicted He/H ratio in the nebulae are significantly smaller than the ...

Lamers, Henny J G L M; Panagia, N; Smith, L J; Langer, N; Lamers, Henny J.G.L.M.; Nota, Antonella; Panagia, Nino; Smith, Linda J.; Langer, Norbert

2001-01-01

185

Effect of chemical composition on luminescence of thiol-stabilized  

E-print Network

Ó to the authors 2007 Abstract Judicious selection of the amount of surfactant during synthesis enables a drastic increase in the photoluminescence efficiency of aqueous CdTe nanocrystals (NCs) stabilized by thioglycolic acid (TGA). Elemental determination of the NCs was undertaken to identify the origin of this effect. The molar ratio of (Te + S) to Cd approached unity when the optimum amount of TGA was used during synthesis, whereas the number of S atoms originating from TGA molecules in one NC (2.6 nm of diameter) remained unchanged at 90 ± 3. This indicates that the core lattice composition at the beginning of synthesis, rather than the surface conditions, affects the photoluminescence efficiency of the NCs even after prolonged refluxing.

Cdte Nanocrystals; Norio Murase; Æ Nikolai Gaponik; Æ Horst Weller; N. Murase; H. Weller

2007-01-01

186

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

187

The chemical composition of fogs and clouds in Southern California  

SciTech Connect

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

Munger, J.W.

1989-01-01

188

Kr-81 terrestrial ages and grouping of Yamato eucrites based on noble gas and chemical compositions  

NASA Astrophysics Data System (ADS)

The ages of Yamato eucrites recovered in Antarctia, and terrestrial ages of nine Yamato eucrites (Y-75011, Y-791826, Y-792511, Y-793164, Y-793547, Y-793548, Y-793570, Y-794002, and Y-794043) were determined based on cosmic-ray produced Kr-81. Based on the terrestrial ages, cosmic-ray exposure ages, noble gas compositions, and chemical compositions, groupings of these Yamato eucrites were established.

Miura, Y.; Nagao, K.; Fujitani, T.

1993-04-01

189

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

190

Thermodynamics for the preparation of SiC-C nano-composites by chemical vapour deposition  

Microsoft Academic Search

SiC-C nano-composites covering every possible combination of carbon and SiC were prepared by chemical vapour deposition. The specific compositions of the deposits were controlled by changing the Si\\/C molar ratio in the source gases at deposition temperatures (Tdep) of 1673 to 1873 K and total gas pressures (Ptot) of 6.7 to 40 k Pa using the SiCl4-C3H8-H2 system. The prediction,

Y. Wang; M. Sasaki; T. Goto; T. Hirai

1990-01-01

191

Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse  

Microsoft Academic Search

Sediment cores were collected from seven lakes in the Subarctic Pasvik watercourse, polluted by sewage waters and air emissions from the Pechenganickel Metallurgical Company, in order to study chemical composition and estimate the intensity of pollution by taking into account background concentration of elements and the vertical and spatial distribution of their contents in cores and surficial layers of sediments.

Vladimir Dauvalter; Nikolay Kashulin; Sergey Sandimirov; Petr Terentjev; Dmitry Denisov; Per-Arne Amundsen

2011-01-01

192

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

193

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

194

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

195

Influence of heating on antioxidant activity and the chemical composition of some spice essential oils  

Microsoft Academic Search

Oxidation of lipids is one of the basic processes causing rancidity in food products. Since application of natural antioxidants may be one of the technically simplest ways of reducing fat oxidation, we studied the effect of heating on antioxidant effectiveness and the chemical composition of basil, cinnamon, clove, nutmeg, oregano and thyme essential oils. When maintained at room temperature, all

A. Tomaino; F. Cimino; V. Zimbalatti; V. Venuti; V. Sulfaro; A. De Pasquale; A. Saija

2005-01-01

196

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

E-print Network

to a thin film growth rate of ca. 4 nm min-1 . Electrodes loaded at 0.010 mg cm-2 Pt (Pt-CNW/CPL) with a PtOne-step synthesis and chemical characterization of Pt-C nanowire composites by plasma sputtering properties.[1-3] Nanomaterials have thus found numerous applications in chemistry, electronics, optics

Boyer, Edmond

197

Chemical composition and oxidative stability of Tunisian monovarietal virgin olive oils with regard to fruit ripening  

Microsoft Academic Search

The chemical composition of virgin olive oil may be influenced by genotype and different agronomic (i.e. fruit ripeness degree, water supply) and technological factors. This article reports the evaluation of the influence of the olive ripening stage on the quality indices, the major and the minor components and the oxidative stability of the two main monovarietal Tunisian cultivars (cvv. Chétoui

Olfa Baccouri; Mokhtar Guerfel; Bechir Baccouri; Lorenzo Cerretani; Alessandra Bendini; Giovanni Lercker; Mokhtar Zarrouk; Douja Daoud Ben Miled

2008-01-01

198

Chemical composition of Titan's haze: Are PAHs present? Melissa G. Trainer,1  

E-print Network

Chemical composition of Titan's haze: Are PAHs present? Melissa G. Trainer,1 Alexander A. Pavlov,2 laboratory studies of haze aerosols analogous to those in Titan's atmosphere have shown evidence particle formation and nitrogen incorporation. We have conducted new experiments simulating Titan haze

Jimenez, Jose-Luis

199

Atmospheric Environment 38 (2004) 805820 Arctic haze, mercury and the chemical composition of snow  

E-print Network

Atmospheric Environment 38 (2004) 805­820 Arctic haze, mercury and the chemical composition of snow in atmospheric aerosol loading (arctic haze) that develops as the Arctic polar front expands southward in March and April. Haze contaminant concentrations in the snow pack were as high south of the Brooks Range

Douglas, Thomas A.

200

Douglas and Sturm, Page 1 ARCTIC HAZE, MERCURY AND THE CHEMICAL COMPOSITION OF SNOW  

E-print Network

Douglas and Sturm, Page 1 ARCTIC HAZE, MERCURY AND THE CHEMICAL COMPOSITION OF SNOW ACROSS loading (arctic haze) that develops as the Arctic polar front expands southward in March and April. Haze contaminants in northwest Alaska is arctic haze. During late winter and early spring, when the Polar Front

Sturm, Matthew

201

Essential oils of Thymus pulegioides and Thymus glabrescens from Romania: Chemical composition and antimicrobial activity  

Microsoft Academic Search

The aim of this work was to analyse the chemical composition and antimicrobial properties of essential oils isolated from two wild-growing spe- cies of thyme (Thymus pulegioides L. and T. glabrescens Willd.) originating from different locations in Romania. The yield of essential oil was determined according to European Pharmacopoeia standards. Qualitative and quantitative analysis of the oils was performed using

Mariana Pavel; Mihailo Ristic; Tatjana Stevic

2010-01-01

202

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

203

Antibacterial activity of Turkish propolis and its qualitative and quantitative chemical composition  

Microsoft Academic Search

The antibacterial activity of propolis from different regions of Turkey was studied, accompanied by TLC and GC-MS analyses of its chemical composition and spectrophotometric quantification of the most important active principles. All six samples were active against the bacterial test strains used; however, samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) were more active than samples 4 (Adana), 5 (Erzurum)

M. Popova; S. Silici; O. Kaftanoglu; V. Bankova

2005-01-01

204

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...

205

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

206

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

E-print Network

Chemical Composition and Insecticidal Properties of Thymus numidicus (Poiret) Essential Oil from-Industrielles'', 17042 La Rochelle, France Abstract: Essential oils of thyme (Thymus numidicus (Poiret)) from Algeria.5 minutes of extraction were tested using the filter paper method. Analysis of the essential oil made

Paris-Sud XI, Université de

207

Construction costs, chemical composition and payback time of high- and low-irradiance leaves  

Microsoft Academic Search

The effect of irradiance on leaf construction costs, chemical composition, and on the payback time of leaves was investigated. To enable more generalized conclusions, three different systems were studied: top and the most-shaded leaves of 10 adult tree species in a European mixed forest, top leaves of sub-dominant trees of two evergreen species growing in small gaps or below the

Hendrik Poorter; Steeve Pepin; A. J. M. Rijkers; Yvonne de Jong; John R. Evans; C. Körner

2006-01-01

208

Radon in soil and chemical composition of spring water near Popocatépetl volcano, Mexico  

Microsoft Academic Search

Soil radon was monitored at two permanent stations on the northern flank of Popocatépetl volcano. Water samples from three springs around the cone were also studied for radon and chemical composition. Radon in soil was recorded using track detectors, and sporadic short-term measurements were obtained with a Clipperton probe. Radon in water samples was measured using a liquid scintillation method.

N. Segovia; M. A. Armienta; J. L. Seidel; M. Monnin; P. Peña; M. B. E. López; M. Mena; C. Valdés; E. Tamez; R. N. López; P. Aranda

2002-01-01

209

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

E-print Network

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

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

1940-01-01

210

Location and chemical composition of microbially induced phosphorus precipitates in anaerobic and aerobic granular sludge  

E-print Network

Location and chemical composition of microbially induced phosphorus precipitates in anaerobic-strength wastewater effluents. Mineral precipitation is shown to occur in the core of microbial granules under will need further investigation as it is certainly due to local microbial activity. Keywords: anaerobic

Boyer, Edmond

211

Influence of Cultivar on Quality Parameters and Chemical Composition of Strawberry Fruits Grown in Brazil  

Microsoft Academic Search

Six strawberry cultivars grown on the same commercial plantation in Brazil were evaluated for their chemical composition and quality attributes at the ripe stage. The profiles of the main soluble sugars, ascorbic acid, and anthocyanins were also obtained during the developmental stages. Results showed significant differences among cultivars in all of the investigated parameters. Cv. Campineiro showed an average value

Beatriz Rosana Cordenunsi; João Roberto Oliveira do Nascimento; MARIA INE Ä S GENOVESE; Franco Maria Lajolo

2002-01-01

212

Chemical compositions and larvicidal activities of leaf essential oils from two eucalyptus species  

Microsoft Academic Search

In the current study, the mosquito larvicidal activity of leaf essential oils and their constituents from two eucalyptus species (Eucalyptus camaldulensis and Eucalyptus urophylla) against two mosquito species, Aedes aegypti and Aedes albopictus, was investigated. In addition, the chemical compositions of the leaf essential oils were analyzed using gas chromatography–mass spectrometry. Results from the larvicidal tests revealed that essential oil

Sen-Sung Cheng; Chin-Gi Huang; Ying-Ju Chen; Jane-Jane Yu; Wei-June Chen; Shang-Tzen Chang

2009-01-01

213

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

214

Improvement of Thermal and Mechanical Properties of Carbon Nanotube Composites through Chemical  

E-print Network

into a polymer matrix by in situ polymerization, to improve the transfer of mechanical load through a chemical-walled nanotubes (SWNTs) and multiwalled nanotubes (MWNTs) have outstanding high Young's modulus, stiffness, and flexibility.5-8 However, despite the many reports published in CN composites with a polymeric matrix,3

Fisher, Frank

215

Chemical composition of the essential oil of Salvia officinalis from Algeria  

Microsoft Academic Search

shown some interesting features of its chemical composition, which is determined by their volatile [10?19] and nonvolatile compounds [20], and their applications in antibacterial [14], antifungal [10], and antioxidant activities [8]. In Algeria flora there are 18 species [21]; however, there are no studies on sage oil of these species growing in Algeria. Here we report our findings on the

T. Dob; T. Berramdane; D. Dahmane; T. Benabdelkader; C. Chelghoum

2007-01-01

216

Chemical compositions and antimicrobial activities of four different Anatolian propolis samples  

Microsoft Academic Search

Propolis means a gum that is gathered by bees from various plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The aims of this study were to evaluate the antimicrobial activity of four different Anatolian propolis samples on different groups of microorganisms including some oral pathogens and comparison between their chemical compositions. Ethanol extracts of

Ataç Uzel; Özant Önça?; Dil?ah Ço?ulu; Ömür Gençay

2005-01-01

217

DETERMINATION OF CHEMICAL COMPOSITION AND GROSS ENERGY OF ALFALFA HAY IN EAST AZARBAIJAN OF IRAN  

Microsoft Academic Search

Considering of alfalfa cultivated area and production amount of its forage in East Azarbaijan is making essential to determine the chemical composition and gross energy. However, we used probability stratified random sampling method for dividing alfalfa-cultivated areas to 32 regions and selected randomly 9 villages from each region. In each village we selected many random samples from dry alfalfa forage

M. R. Asadpour; M. A. Moosavi; M. Ghayoor; A. Ayazi; H. Monirifar

218

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

219

Ice Nuclei, Rainwater Chemical Composition, and Static Cloud Seeding Effects in Israel  

Microsoft Academic Search

This study analyzed the temporal and spatial variation of natural ice nuclei (IN), total suspended particles (TSP), and rainwater chemical composition (RCC) in Israel. This research is complementary to the statistical analyses of cloud seeding, which have shown significant positive seeding effects only in northern Israel, together with detrimemtal effects of desert dust.It was observed that the concentration of continental

Yoav Levi; Daniel Rosenfeld

1996-01-01

220

Morphology and chemical composition of airborne Saharan dust during the AEROsol and Ocean Science Expeditions (AEROSE)  

Microsoft Academic Search

The morphology and chemical composition of aerosols associated with Saharan dust outbreaks between July 2006 and 2009 off-shore of the African continent above the tropical North Atlantic Ocean is investigated. Conducted aboard the NOAA research ship Ronald H. Brown (RHB). The trans-Atlantic AEROsol and Ocean Science Expeditions (AEROSE) are a series of intensive atmospheric field campaigns designed to investigate the

Esther B. Effiong; Vernon R. Morris; Nicholas R. Nalli

2011-01-01

221

Determination of Chemical Composition, Mineral Contents,and Protein Quality of Poultry By-Product Meal  

Microsoft Academic Search

2 Abstract: In order to study the chemical composition, mineral contents and protein quality of poultry by- product meal (PBPM), 10 composed samples of PBPM produced in Iran were provided during two months sampling period from rendering units of three industrial poultry slaughter-houses. The proximate analysis showed that the average dry matter (DM), ether extract (EE), crude protein (CP), crude

Hossein Jahanian Najafabadi; Hassan Nassiri Moghaddam; Javad Pourreza; Feridoon Eftekhar Shahroudi; Abolghasem Golian

2007-01-01

222

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

223

Chemical composition of Schinus molle essential oil and its cytotoxic activity on tumour cell lines  

Microsoft Academic Search

The leaf essential oil hydrodistilled from Schinus molle grown in Costa Rica was characterised in terms of its chemical composition, antioxidant activity, ability to induce cytotoxicity and the mechanism of cell death involved in the process. As a result, 42 constituents, accounting for 97.2% of the total oil, were identified. The major constituents of the oil were ?-pinene and ?-pinene.

Cecilia Díaz; Silvia Quesada; Oscar Brenes; Gilda Aguilar; José F. Cicció

2008-01-01

224

The Chemical Composition and Period Change Rate of the Anomalous Cepheid V19 in NGC 5466  

Microsoft Academic Search

A detailed model atmosphere and chemical composition analysis has been made of the brightest known anomalous Cepheid, V19 in the globular cluster NGC 5466. Our study is based on 30 minute CCD echelle spectrograms (4300 <= lambda <= 6630 A) acquired in 1995 and 1996 with the HIRES spectrograph on the 10 m Keck-I telescope. New CCD photometric observations from

James K. McCarthy; James M. Nemec

1997-01-01

225

Chemical composition and cytotoxic and antimicrobial activity of Calycotome villosa (Poiret) Link leaves  

Microsoft Academic Search

The chemical composition of the essential oil and methanol extract of Calycotome villosa (Poiret) Link leaves collected in Sardinia (Italy) has been studied by analytical and spectroscopic methods. Falcarinol and some alcohols, terpenes, furan derivatives, and paraffins have been isolated from the essential oil. Thirteen alkaloids and falcarinol have been identified in the chloroform fraction of the basic methanol extract.

Giuseppe Loy; Filippo Cottiglia; Donatella Garau; Delia Deidda; Raffaello Pompei; Leonardo Bonsignore

2001-01-01

226

Chemical composition and antimicrobial activity of the essential oils of Gentiana asclepiadea L  

Microsoft Academic Search

The present paper describes the chemical composition and antimicrobial activity of the essential oils of Gentiana asclepiadea L., collected in Serbia. The essential oils were obtained from the underground part (root and rhizome) and aerial part (stem, leaves and flowers) of the plant by hydrodistillation and analyzed by GC and GC-MS. The major compounds in the oil from the underground

Mihailovic Vladimir; Vukovic Nenad; Niciforovic Neda; Solujic Slavica; Sukdolak Slobodan

2010-01-01

227

Chemical composition and antimicrobial activity of the essential oil from Satureja horvatii Šili? (Lamiaceae)  

Microsoft Academic Search

The present paper describes the chemical composition and antimicro- bial activity of the essential oil of the endemic species Satureja horvatii Šili?, collected in Montenegro. The essential oil was obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC-MS. From the 34 com- pounds representing 100 % of the oil, the major compound was the phenolic

MIHAILO RISTI?; VIOLETA SLAVKOVSKA; Jelena Antic-Stankovic; Marina Milenkovic

2008-01-01

228

Grass Tetany Hazard of Cereal Forages Based upon Chemical Composition1  

Microsoft Academic Search

The occurrence of grass tetany in cattle grazing small grains pastures led us to examine the forage chemical composition and to suggest the relative risk of grass tetany to cattle grazing each forage. Early spring vegetative growth of wheat (Triticum aestivum L.) and crested wheatgrass (Agropyrots deser- torum (Fisch.) Schuh) was periodically sampled from 3 x 20 m plots established

H. F. Mayland; D. L. Grunes; V. A. Lazar

1976-01-01

229

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

230

Chemical Analyses.  

National Technical Information Service (NTIS)

As a preliminary study on the effects of chemical aging of polymer materials MERL and TRI have examined two polymeric materials that are typically used for offshore umbilical applications. These two materials were Tefzel, a copolymer of ethylene and tetra...

J. W. Bulluck, R. A. Rushing

1994-01-01

231

Chemical Composition of Rocks and Soils at Gale Crater, Mars  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

232

Chemical sensors  

DOEpatents

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

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

1992-01-01

233

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

234

Chemical composition of an exo-planetary debris disk  

NASA Astrophysics Data System (ADS)

In the recent years, four white dwarfs with gaseous planetary debris disk were discovered. It is thought that they were created by tidally disrupted planetary bodies. This offers the unique possibility to determine directly the composition of exo-planetary material by spectroscopic means. However, only very few bright emission lines from the optically thin gas disk are detectable because the white dwarf's photospheric flux in the near-IR to UV spectral band is rather strong. Here we propose to perform far-UV observations of one of these WDs shortward of 115 nm where the WD flux is effectively blocked by broad and deep photospheric hydrogen Lyman lines. We expect to detect disk emission lines from carbon and silicon. Together with optical and near-UV archival spectra that exhibit lines from Ca, Mg, and Fe, this enables us for the first time to determine the relative abundances of most of the abundant elements in the disk. In particular, we may decide whether the planetary debris was formed from chondritic or bulk-Earth like material.

Werner, Klaus

2012-10-01

235

Huygens/ACP: An instrument for aerosols chemical composition measurements  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

236

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

237

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

238

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

239

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

240

Chemical Synthesis of Proteins  

PubMed Central

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

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

2010-01-01

241

Chemical compositions and classifica tion of five thermally altered carbonaceous chondrites  

NASA Astrophysics Data System (ADS)

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

Noronha, Bianca A.; Friedrich, Jon M.

2014-08-01

242

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

243

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

244

Chemical composition of ? Scuti stars: 1. AO CVn, CP Boo, KW Aur  

NASA Astrophysics Data System (ADS)

We used high-resolution echelle spectra acquired with the 1.5-m Russian-Turkish Telescope to determine the fundamental atmospheric parameters and abundances of 30 chemical elements for three ? Scuti stars: AOCVn, CP Boo, and KWAur. The chemical compositions we find for these stars are similar to those for Am-star atmospheres, though some anomalies of up to 0.6-0.7 dex are observed for light and heavy elements. We consider the effect of the adopted stellar parameters (effective temperature, log g, microturbulent velocity) and the amplitude of pulsational variations on the derived elemental abundances.

Galeev, A. I.; Ivanova, D. V.; Shimansky, V. V.; Bikmaev, I. F.

2012-11-01

245

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

E-print Network

:~p$ne$$ 9 -FK~( Q9"y.a *e4*&; I * Relation of the occurrence of Cotton Root7*'. Rot to the Chemical Composition of Soils -- AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON, President Soils in which cotton root rot generally occurs... does not generally occur on these soils. This indicates the action of inhibitory factors in alluvial soils not usually operative to the same degree in heavy upland soils. The chemical colnposition of local areas of soil containing active root rot...

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

1935-01-01

246

Chemical composition and larvicidal activity of several essential oils from Hypericum species from Tunisia.  

PubMed

The chemical composition of the essential oils extracted from some Tunisian Hypericum species and their larvicidal activity against Culex pipiens larvae were evaluated. The chemical compositions of the essential oils from the aerial plant parts were analyzed using gas chromatography-mass spectrometry. One hundred and thirty-four compounds were identified, ranging between 85.1 and 95.4 % of the oil's composition. The components were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. The larvicidal activity of the essential oils was evaluated using a method recommended by WHO. Larvicidal tests revealed that essential oils from the Hypericum species have a significant larvicidal activity against C. pipiens, with LC(50) ranging between 102.82 and 194.70 ppm. The most powerful essential oils against these larvae were Hypericum tomentosum and Hypericum humifusum samples, followed by the essential oil of Hypericum perforatum. PMID:23180126

Rouis, Zyed; Laamari, Ali; Abid, Nabil; Elaissi, Ameur; Cioni, Pier Luigi; Flamini, Guido; Aouni, Mahjoub

2013-02-01

247

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

248

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

249

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

250

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

251

INFLUENCE OF THE CHEMICAL COMPOSITION ON THE BEHAVIOR OF AUSTENITIC STAINLESS STEEL IN FLUID LAYER NITRIDING PROCESS  

Microsoft Academic Search

The main factors that influence the stainless steel behavior to the nitriding process are: chemical composition, nitriding temperature, treatment time. Researches have revealed that, with low temperature nitriding, the chemical composition expressed directly by the alloying elements or indirectly by the austenite or ratio ECr\\/ENi stability index decisively influences the characteristics of the nitride layer. The high alloyed steels having

Ovidiu DIMA

252

Chemical Composition and Insecticidal Activity of Artemisia scoparia Essential Oil against Three Coleopteran Stored-Product Insects  

Microsoft Academic Search

Chemical composition of the essential oil from Artemisia scoparia Waldst et Kit, and its fumigant and repellent activity were investigated against three stored product insects, Callosobruchus maculatus (Fab.), Sitophilus oryzae (L.), and Tribolium castaneum (Herbst). Dry ground leaves were subjected to hydrodistillation using a modified clevenger-type apparatus and the chemical composition of the volatile oil was studied by GC-MS. Nineteen

Maryam Negahban; Saeid Moharramipour; Fatemeh Sefidkon

2006-01-01

253

Food availability as a selective factor on the chemical compositions of midwater fishes in the eastern North Pacific  

Microsoft Academic Search

In September and October 1980 we examined the relationships between food availability, depth, and chemical composition among 12 midwater fish species, from three adjacent areas of the eastern North Pacific: the eastern gyre, the California Current, and the transitional region between them. By comparing trends in chemical composition across a geographical productivity gradient, the influence of food availability could be

T. G. Bailey; B. H. Robison

1986-01-01

254

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...Waste and Porous Surfaces in Accordance With... § 761.292 Chemical extraction and analysis of individual samples...this part, for chemical extraction of...

2010-07-01

255

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

256

Chemical vapor infiltration of fiber-reinforced SiC matrix composites  

SciTech Connect

Continuous fiber-reinforced SiC matrix composites with different reinforcement geometries have been successfully fabricated by a chemical vapor infiltration technique. The density, pore distribution and microstructure development of the resulting composites at various processing stages were characterized. The mechanical properties, including tensile, flexural, fracture toughness, environmental resistance and deformation mechanisms were evaluated. The results indicate that a ceramic composite with high strength, fracture toughness and good environmental resistance can be produced through the optimization of preform geometry and CVI parameters. 13 refs.

Burkland, C.V.; Yang, J.M. (Amercom, Inc., Chatsworth, CA (USA); California Univ., Los Angeles (USA))

1989-10-01

257

Chemical sensors  

SciTech Connect

The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section.

Hubbard, C.W.; Gordon, R.L.

1987-05-01

258

Nest marking behavior and chemical composition of olfactory cues involved in nest recognition in Megachile rotundata.  

PubMed

In-nest observations of the solitary bee, Megachile rotundata (F.), revealed that nesting females apply olfactory cues to nests for nest recognition. On their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen. The removal of bee-marked sections of the nest resulted in hesitation and searching behavior by females, indicating the loss of olfactory cues used for nest recognition. Chemical analysis of female cuticles and the deposits inside marked nesting tubes revealed the presence of hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. Chemical compositions were similar across tube samples, but proportionally different from cuticular extracts. These findings reveal the importance of lipids as chemical signals for nest recognition and suggest that the nest-marking cues are derived from a source in addition to, or other than, the female cuticle. PMID:23905742

Guédot, Christelle; Buckner, James S; Hagen, Marcia M; Bosch, Jordi; Kemp, William P; Pitts-Singer, Theresa L

2013-08-01

259

Microbial and chemical composition of liquid-associated bacteria in goats' rumen and fermenters.  

PubMed

This study was undertaken to investigate the relationship between chemical composition and microbial profile of rumen liquid-associated bacteria (LAB) in vivo (Murciano-Granadina goats) and in a rumen simulation system (single-flow continuous-culture fermenters). To achieve this aim, analyses of purine bases along with some molecular techniques (quantitative PCR to assess abundance and DGGE to identify biodiversity and bacterial profile) were carried out. A control diet (AHC) based on alfalfa hay (AH) and concentrate (C) in a 1:1 ratio and two experimental diets (AHCBI and AHCBII), in which concentrate was partially replaced with multinutrient blocks, were used. Diets AHCBI and AHCBII included multinutrient blocks differing in the relative amount of two-stage olive cake and the source of protein (sunflower meal vs. fava beans). We aimed to investigate the effect of these blocks on rumen microbiota to evaluate their potential as safe substitutes of cereal-based concentrates. Similar patterns of response to diet were found for chemical composition, microbial abundances and diversity in LAB isolated from goat's rumen and fermenters. Whereas bacterial density (log10 gene copies/g FM: 11.6 and 9.4 for bacteria and methanogens, respectively, in rumen) and diversity indexes (Shannon index: 3.6) were not affected by diet, DGGE analyses showed that bacterial community profile was affected. The cluster analysis suggested differences in bacterial profile between LAB pellets isolated from the rumen of goat and fermenters. A relationship between chemical composition and bacterial community composition in LAB pellets seems to exist. Changes in the former were reflected in the bacterial community profile. Further research is needed to clarify the relationship between chemical and microbial composition of ruminal bacterial pellets with diets of different quality. PMID:24460876

Abecia, L; Soto, E C; Ramos-Morales, E; Molina-Alcaide, E

2014-10-01

260

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

261

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

262

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

263

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.

264

Chemical Evolution  

E-print Network

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

Francesca Matteucci

2007-04-05

265

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

266

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't tell- a science educator- not affiliated with any specific organization

2011-10-10

267

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

268

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

NASA Astrophysics Data System (ADS)

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

Khan, A.; Joshi, S.

2014-09-01

269

[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

270

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

NASA Astrophysics Data System (ADS)

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

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

2002-09-01

271

Microflora and chemical composition of dental plaque from subjects with hereditary fructose intolerance.  

PubMed Central

We compared the microbiological and chemical composition of dental plaque from subjects with hereditary fructose intolerance who restrict their dietary sugar intake with that of control subjects who do not. The two groups showed no significant differences in chemical composition of plaque: the mean protein, carbohydrate, calcium, magnesium, and phosphate contents were similar. Dental plaque from both groups contained similar numbers of total colony-forming units per microgram of plaque protein, and Streptococcus sanguis, an indigenous nonpathogen, was isolated with equal frequency from plaque samples of both groups. However, potentially odontopathic Streptococcus mutans and Lactobacillus were isolated three to four times more frequently from plaque samples of control subjects than from plaque samples of subjects with hereditary fructose intolerance. Clearly, diet (sucrose in particular) influences the colonization and multiplication of specific cariogenic organisms in dental plaque. PMID:7399699

Hoover, C I; Newbrun, E; Mettraux, G; Graf, H

1980-01-01

272

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

273

Spectrum and chemical composition of the remarkable planetary nebula NGC 6537  

NASA Technical Reports Server (NTRS)

The planetary nebula NGC 6537 appears to be an irregular bipolar object. Conventional procedures have been employed to observe the spectrum of NGC 6537 with the image dissector scanner at the Lick 3-m telescope. Both red- and green-sensitive tubes were employed in order to cover the spectrum from the practical UV limit near lambda 3300 A to the near-infrared limit near lambda 8600 A. The instrumental response function was determined on the basis of the observation of suitable comparison stars. On Oct. 23, 1984, observations with the International Ultraviolet Explorer (IUE) were obtained. A table containing the optical region spectrum of NGC 6537 is presented along with a table providing the UV fluxes, a table listing the ionic concentrations, and a table with data describing the chemical composition of NGC 6537. Attention is given to theoretical models and the determination of the nebular chemical composition, and aspects of plasma diagnostics.

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

1985-01-01

274

Microstructure and properties of ultrafine WC-10Co composites with chemically doped VC  

Microsoft Academic Search

Vanadium carbide is the most effective grain growth inhibitor for ultrafine WC-Co composites due to its high solubility and\\u000a mobility in the cobalt phase at relatively low temperatures; however, there are still some debates over the best way to introduce\\u000a it into the WC-Co formulation. In this paper, the differences between admixed and chemically doped grain growth inhibitors\\u000a on the

Cholsong Pang; Ji Luo; Zhimeng Guo

2011-01-01

275

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

Microsoft Academic Search

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

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

2000-01-01

276

Chemical composition and antimicrobial activities of essential oil and its components from Lebanese Origanum syriacum L  

Microsoft Academic Search

The chemical composition of essential oils isolated by hydrodistillation from the aerial parts of cultivated and wild Origanum syriacum were analyzed by gas chromatograph (GC) and GC\\/mass spectrometry (GC\\/MS). Regardless of growing habitat, both oils were characterized as carvacrol\\/?-terpinene chemotypes. High in vitro antimicrobial activities of essential oil were attributed to the high content of phenolic derivative such as carvacrol.

Ludmilla Ibrahim; Mohamad Karaky; Pascale Ayoub; Nawal El Ajouz; Said Ibrahim

2012-01-01

277

Water\\/rock interactions and changes in chemical composition during zeolite mineralization  

Microsoft Academic Search

Systematic analysis and comparative study of the chemical compositions of rocks and ores from the main types of zeolite deposits\\u000a in the surroundings of the Songliao Basin have shown that the process of formation of zeolite from volcanic and pyroclastic\\u000a rocks is generally characterized by the relative purification of SiO2, i.e., SiC2\\/Al2O3 ratios tend to increase, alkali earth elements (CaO

Shouting Zhang; Pengda Zhao; Zhanzhang Xu; Minghua Zheng

2001-01-01

278

The essential oil of Senecio graveolens ( Compositae): chemical composition and antimicrobial activity tests  

Microsoft Academic Search

The chemical composition of the essential oil obtained from Senecio graveolens (Compositae) was analyzed by GLC–MS and the components identified were: isovaleraldehyde, ?-pinene, ?-phellandrene, ?-terpinene, p-cymene, sabinene, ?-terpinene, 1-methyl-4-isopropenylbenzene, terpinolene, terpinen-4-ol, piperitenone, ?- and ?-eudesmol. The investigation by the agar-well diffusion method of the antimicrobial activity of the essential oil proved that it has antibacterial effects on Micrococcus luteus ATCC

Cristina Pérez; Alicia Mariel Agnese; José Luis Cabrera

1999-01-01

279

KEY COMPARISON: Final report on CCQM-K57: Chemical composition of clay  

Microsoft Academic Search

After the successful completion of the pilot study, CCQM-P65 [1], the Inorganic Analysis Working Group of CCQM agreed to conduct key comparison CCQM-K57, Chemical composition of clay, in Paris, April 2006. The natural mass fraction levels of five elements---Si, Ca, Fe, Al and Mg---were measured and reported as oxides in clay. Six national metrology institutes participated in CCQM K57, and

Antonio Salas; Estele Ramírez

2009-01-01

280

[Chemical composition of breast milk in females with preterm deliveries in the Primorsky Krai].  

PubMed

In the article there are presented data on the chemical composition of breast milk in females with preterm labor in the Primorye Territory, who were in the Department of newborns for premature babies of the Municipal Institution of Health "Children's city clinical hospital" in Vladivostok during 2010-2011 to care for their newborn infants. Laboratory studies were performed in the Federal State Institution of Health "Center of Hygiene and Epidemiology in the Primorye Territory." PMID:24340586

Beniova, S N; Rudenko, N V; Maslov, D V; Anan'ev, V Iu

2013-01-01

281

Iron–iron oxide composite thin films prepared by chemical vapor deposition from iron pentacarbonyl  

Microsoft Academic Search

Iron–iron oxide (Fe–Fe3O4) composite thin films were prepared by an atmospheric-pressure chemical vapor deposition method. Iron pentacarbonyl and carbon dioxide gas were used as source materials. The effect of carbon dioxide mole fraction on the structure of the film is discussed. For both Fe–Fe3O4 and Fe–?-Fe2O3 films, the magnetic properties were obtained from the hysteresis curve of in-plane magnetization. The

Toshiro Maruyama; Yoshitaka Shinyashiki

1998-01-01

282

Acaricidal activity and chemical composition of the essential oil from three Piper species  

Microsoft Academic Search

The chemical composition of the essential oil obtained by hydrodistillation of the aerial parts of Piper amalago, Piper mikanianum, and Piper xylosteoides was elucidated by gas chromatography (GC) and GC\\/mass spectrometry analyses. P. mikanianum and P. xylosteoides essential oils presented phenylpropanoids as their main compounds (67.89% and 48.53%, respectively) whereas P. amalago was rich in monoterpene and sesquiterpene hydrocarbons (84.95%).

Alexandre de B. F. Ferraz; João Marcio Balbino; Claudia Alcaraz Zini; Vera Lucia S. Ribeiro; Sérgio A. L. Bordignon; Gilsane von Poser

2010-01-01

283

Chemical Composition of the Essential Oils of Achillea millefolium L. Isolated by Different Distillation Methods  

Microsoft Academic Search

The chemical composition of the essential oil from flowering tops of Achillea millefolium L. isolated by different distillation methods was studied. Samples were hydrodistilled with Clevenger-type (HD), simultaneous micro-distillation-extraction (SMDE), and microwave (MAHD) apparatus. The yields were 0.46% ± 0.03 for the HD and 0.48% ± 0.03 for the MAHD (v\\/w, volume\\/dry weight). The oils were analyzed by GC and

Carlo I. G. Tuberoso; Adam Kowalczyk

2009-01-01

284

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

285

Effect of Germination on the Chemical Composition and Nutritive Value of Amaranth Grain  

Microsoft Academic Search

Cereal Chem. 67(6):5 19-522 Changes in chemical composition and in nutritive value during germi- in protein, crude fiber, and ash content, whereas lipid and phytic acid nation of amaranth grain were studied. One variety each of Amaranthus content decreased with respect to germination time. Reducing sugars, hypochondriacus, A. cruentus, and A. caudatus was germinated for 0, total sugars, and damaged

A. S. COLMENARES DE RUIZ; R. BRESSANI

286

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

Microsoft Academic Search

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

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

2008-01-01

287

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

Microsoft Academic Search

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

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

2011-01-01

288

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

289

Anti-inflammation activity and chemical composition of flower essential oil from Hedychium coronarium  

Microsoft Academic Search

Hedychium coronarium Koen. (Family Zingiberaceae), popularly named butterfly ginger, is widely available in tropical and subtropical regions. It has been used in folk medicine for many conditions, such as contusion inflammation, anti-rheumatic and so on. In this study, chemical compositions and anti-inflammatory activity of this flowers' essential oil were investigated for the first time. Followed by GC-MS analysis, a total

Y. Lu; C. X. Zhong; L. Wang; C. Lu; X. L. Li; P. J. Wang

290

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; Chaib, Faiza; Merghache, Djamila; El Amine, Mohamed; Djabou, Nassim; Muselli, Alain; Tabti, Boufeldja; Costa, Jean

2014-01-01

291

Chemical composition and antimicrobial activity of Thymus pannonicus All. ( Lamiaceae ) essential oil  

Microsoft Academic Search

This paper presents the results of a study on chemical composition and antimicrobial activity of Thymus pannonicus All. (Lamiaceae) essential oil from Vojvodina province (north of Serbia). The investigated oil was hydrodistilled from a flowering plant\\u000a and analysed by GC and GC-MS. Fifty-three constituents were identified (>97% of total oil), with geranial (41.42%, w\\/w) and\\u000a neral (29.61%, w\\/w) as the

Zoran Maksimovi?; Marina Milenkovi?; Dragana Vu?i?evi?; Mihailo Risti?

2008-01-01

292

Chemical Composition and In-vitro Antimicrobial Activity of Barleria lupulina Essential Oil  

Microsoft Academic Search

The chemical composition by gas chromatography mass spectroscopy analysis and antibacterial property of Barleria lupulina essential oil were performed. The main components of the essential oil included cyclobutane,1,1-dimethyl- 2-octyl, 2-Hexyl-1-octanol, 1, 2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester and 1-hentetracontanol. B. lupulina essential oil exhibited activity against Bacillus pumilus and Staphylococcus aureus, but was inactive against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and

M. Sarmad; A. Mahalakshmipriya; K. Senthil

2012-01-01

293

Chemical Composition and Antimicrobial Variability of Satureja montana L. Essential Oils Produced During Ontogenesis  

Microsoft Academic Search

The essential oils obtained from Satureja montana L. harvested in central part of Dalmatia (Croatia) at three ontogenical stages were evaluated for their chemical composition and antimicrobial activity. GC\\/MS analyses revealed the presence of 33 compounds in the oils. Carvacrol (52.4>26.2>16.1%) was found to be the main constituent especially before flowering while p-cymene (3.8<15.2<25.6%) increased through flowering. The antimicrobial activity

Skoibuai? Mirjana; Bezi? Nada

2004-01-01

294

Chemical Composition and Antimicrobial Activity of the Essential Oil of Stachys milanii Petrovi?  

Microsoft Academic Search

The chemical composition and antimicrobial activity of the hydrodistilled essential oil isolated from the aerial parts of Stachys milanii Petrovi?, a species endemic to central and eastern regions of the Balkan Peninsula, were examined for the frst time. Fourteen compounds, predominantly monoterpenes, representing 92.2% of the total oil, were identifed, with borneol (49.5%) and terpinen-4-ol (13.2%) as major components. The

Radosav M. Pali?; Jelena S. Lazarevi?; Gordana S. Stojanovi?; Vladimir N. Ran?elovi?

2006-01-01

295

Novel thermal gradient chemical vapor infiltration process for carbon-carbon composites  

Microsoft Academic Search

Solid cylindrical carbon-carbon composites were processed using conventional thermal gradient chemical vapor infiltration. High thermal conductivity (55 W\\/m·°C) carbon fibers (48 k) were inserted in the center of a cylindrical low thermal conductivity (0.15 W\\/m·°C) needle punched carbon felt preform, to create a thermal gradient because of the difference in thermal conductivities. The hottest portion (900–1200 °C) was along the

Shameel Farhan; Ke-zhi LI; Ling-jun GUO

2007-01-01

296

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

297

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

Microsoft Academic Search

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

R. E. Hannigan; K. H. Johannesson

2001-01-01

298

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

299

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

300

Chemical Composition of Several Pulsating Variable Stars of the ? Boo and ? Sct Types  

NASA Astrophysics Data System (ADS)

Objects. We present investigation of four pulsating stars: ? Boo, HD210111, ? Pup and V2314 Oph. Observations. High resolution spectroscopic observations of these stars were made with the 2.7 meter telescope at the McDonald observatory, the VLT and the 2 meter telescope at the Terskol observatory. Photometric observations of V2314 Oph were secured using the 1.2- to 0.4-meter telescopes at five observatories, namely Bohyunsan & Sobak (Korea), Crimea (Ukraine), Maidanak (Uzbekistan), and Dushak-Erekdag (Turkmenistan). Methods. Chemical composition was investigated using a spectrum synthesis method for all elements except iron. A frequency analysis of photometric data of V2314 Oph was made. Results. ? Boo - We found the abundances of several light elements, which were not investigated earlier. HD210111 - upper limits of abundances of La, Ce, and Nd and the abundance of Dy and Yb are found for the first time. The profiles of lines in the spectrum are clearly disturbed by pulsation. V2314 Oph appears to be a new ? Boo type star. Its chemical composition is presented for the first time as also are the values of several frequencies of light variations. For ? Pup, we give a detailed chemical composition for 33 elements. The abundance pattern of this star is similar to that of ? Sct.

Gopka, V.; Yushchenko, A.; Kim, C.; Lambert, D.; Rostopchin, S.; Kim, S.-L.; Jeon, Y.-B.; Dorokhova, T.; Tarasov, A.; Chernyshova, I.

2007-06-01

301

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

302

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

303

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

304

The influence of Wickerhamomyces anomalus killer yeast on the fermentation and chemical composition of apple wines.  

PubMed

The aim of this study was to determine the influence of two different Wickerhamomyces anomalus strains, CBS 1982 and CBS 5759, on the chemical composition and sensory characteristics of Gloster apple wines. They were inoculated into unpasteurized as well as pasteurized apple musts together with a S. cerevisiae strain as a mixed culture. Fermentation kinetics, basic enological parameters, antioxidant properties as well as selected polyphenol, volatile compound, and organic acid contents were analyzed during the experiments. Apple wines obtained after spontaneous fermentation were characterized by high volatile acidity, increased concentrations of acetaldehyde, and volatile esters, as well as the lowest amounts of ethyl alcohol and higher alcohols compared with other samples. Addition of 0.05 g L(-1) W. anomalus killer strains to the unpasteurized must significantly changed the fermentation kinetics and chemical composition of apple wines. The value of volatile acidity was highly decreased, while the amount of higher alcohols and titratable acidity increased. Pasteurization of must improved the fermentation efficiency. Higher amounts of polyphenol compounds and lower amounts of malic acid were also detected. Application of W. anomalus strains together with S. cerevisiae yeast as a mixed culture positively influenced the chemical composition and sensory features of produced apple wines. PMID:24750993

Satora, Pawel; Tarko, Tomasz; Sroka, Pawel; Blaszczyk, Urszula

2014-08-01

305

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

306

Chemically produced tungsten-praseodymium oxide composite sintered by spark plasma sintering  

NASA Astrophysics Data System (ADS)

Pr2O3 doped W composite were synthesized by a novel wet chemical method and spark plasma sintering. The grain size, relative density and the Vicker hardness HV0.2 of Pr2O3/W samples were 4 ?m, 98.3% and 377.2, respectively. The tensile strength values of Pr2O3/W were higher than those of pure W. As the temperature rises from 25 °C to 800 °C, the conductivity of pure W and W-1 wt% Pr2O3 composites decreased with the same trend, was above 150 W/m K.

Ding, Xiao-Yu; Luo, Lai-Ma; Lu, Ze-Long; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

2014-11-01

307

Chemical composition of oils from recently discovered fields in West Lithuania  

NASA Astrophysics Data System (ADS)

Four minor oil discoveries have been made in West Lithuania in recent years. Studies of the oil composition show that its physical and chemical properties (density, viscosity, petrol content, etc.) and the group composition of hydrocarbons (content of saturated and aromatic hydrocarbons, tars and asphaltenes) mainly depend on the formation conditions and distances of migration between the kitchen and accumulation areas. According to the distribution patterns of n-alkanes and isoprenoids, the examined oils are comparable and generated from sapropel organic matter. There are certain differences in biomarker and carbon isotope data, indicating oil generation from different source rocks containing organic matter of different catagenesis.

Zdanavi?i?t?, Onyt?; Dakhnova, Marina; Kleinas, Ar?nas

2008-01-01

308

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

PubMed Central

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

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

2010-01-01

309

Exploring the chemical sensitivity of a carbon nanotube/green tea composite.  

PubMed

Single-walled carbon nanotubes (SWNTs) possess unique electronic and physical properties, which make them very attractive for a wide range of applications. In particular, SWNTs and their composites have shown a great potential for chemical and biological sensing. Green tea, or more specifically its main antioxidant component, epigallocatechin gallate (EGCG), has been found to disperse SWNTs in water. However, the chemical sensitivity of this SWNT/green tea (SWNT/EGCG) composite remained unexplored. With EGCG present, this SWNT composite should have strong antioxidant properties and thus respond to reactive oxygen species (ROS). Here we report on fabrication and characterization of SWNT/EGCG thin films and the measurement of their relative conductance as a function of H(2)O(2) concentrations. We further investigated the sensing mechanism by Fourier transform infrared (FTIR) spectroscopy and field-effect transistor measurements (FET). We propose here that the response to H(2)O(2) arises from the oxidation of EGCG in the composite. These findings suggest that SWNT/green tea composite has a great potential for developing simple resistivity-based sensors. PMID:21043457

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

2010-11-23

310

Impact of melt segregation on chemical composition with application to deep crustal hot zones  

NASA Astrophysics Data System (ADS)

Models of heat transfer during the emplacement of mantle-derived basaltic sills in the mid- to lower crust demonstrate that large volumes of evolved melt may be generated in deep crustal hot zones (DCHZ). These models consider only the thermal evolution of a DCHZ, yet melt must also segregate from along the grain boundaries where it initially resides to form a magma which leaves the DCHZ. However, models which include melt migration describe phase change using simple melt fraction-temperature relations, which do not capture the impact of melt segregation on the chemical evolution of melt and residual solid. We present a model of melting and buoyancy-driven melt segregation in which phase change is described using a phase diagram and the chemical evolution of the melt and residual solid is properly captured. Melt migration is assumed to occur along grain boundaries so local thermodynamic equilibrium is maintained. We begin by using a simple binary phase diagram and model a 1-D column with several different initial compositions and thermal boundary conditions. We investigate this simple case because it could be closely replicated in the laboratory, and allows aspects of the physics which hitherto have been poorly understood to be clearly observed and explained. It is trivial to extend our model to more complex systems. For an initially homogenous column, in which the fraction of component A is less than the eutectic composition, we find that the melt fraction at the base decreases and the bulk composition becomes enriched in component A, while the melt fraction at the top increases and the bulk composition tends towards the eutectic composition. Melt segregation provides a mechanism for accumulating melt of (or close to) the eutectic composition, but at much higher melt fractions than predicted by purely thermal models; for example, static melting to 10% may yield the eutectic composition, but melt segregation allows that composition to accumulate to 100%. For a heterogeneous column, in which layers at the top and base have different initial fractions of component A but lie on the same side of the eutectic composition, the behaviour is similar to the homogenous case. However, if the layers initially lie on different sides of the eutectic composition, mixing of the melt occurs at the interface between the layers so the melt composition can be very close to (or the same as) the eutectic composition. Consequently, very large melt fractions can be generated even though the temperature remains fixed. Our results suggest that chemical evolution in DCHZ occurs because the temperature varies both temporally and spatially. Temporal variations occur in response to heat transfer and are captured by purely thermal models. However, spatial variations are also important, because melt and residual solid migrate during segregation and locally equilibrate at different temperatures. This leads to phase change and chemical evolution which is not captured by purely thermal models, or simple melt fraction-temperature relations, yet can have a significant impact on chemical composition.

Solano, J.; Jackson, M.; Sparks, R. S.; Blundy, J. D.

2010-12-01

311

X-ray tomographic study of chemical vapor infiltration processing of ceramic composites  

SciTech Connect

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 individual fiber tows and to follow the closure of macroscopic pores in situ. The experiments provide a direct test of a recently proposed model that describes how the surface area available for matrix deposition changes during infiltration. The measurements indicate that this surface area is independent of the fiber architecture and location within the preform and is dominated by large-scale macroporosity during the final stages of composite consolidation. The measured surface areas are in good agreement with the theoretical model. 12 refs., 4 figs.

Kinney, J.H.; Haupt, D.; Saroyan, R.A. (Lawrence Livermore National Lab., CA (United States)); Breunig, T.M.; Nichols, M.C. (Sandia National Laboratories, Livermore, CA (United States)); Starr, T.L.; Stock, S.R.; Butts, M.D. (Georgia Inst. of Technology, Atlanta (United States))

1993-05-07

312

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

PubMed

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 individual fiber tows and to follow the closure of macroscopic pores in situ. The experiments provide a direct test of a recently proposed model that describes how the surface area available for matrix deposition changes during infiltration. The measurements indicate that this surface area is independent of the fiber architecture and location within the preform and is dominated by large-scale macroporosity during the final stages of composite consolidation. The measured surface areas are in good agreement with the theoretical model. PMID:17746112

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

1993-05-01

313

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

314

Chemical peel.  

PubMed

Chemical face peeling as described in this article produces gross and microscopic changes in the skin which are permanent. The most important aspect in assuring the success of this procedure is the proper selection of patients. The primary use of this procedure is for the purpose of eliminating wrinkles, whether as the primary or ancillary procedure, such as regional peeling. Chemical peeling of the face is a valuable adjunct in the treatment of the aging face and can produce some rather dramatic results with the careful selection of patients and meticulous attention to detail in carrying out the peel, as well as the exact adherence to the post peel instructions by the patient. PMID:639446

Mosienko, P; Baker, T J

1978-01-01

315

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

316

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 ...

Hicken, Mrs.

2009-05-04

317

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; Yeol Lee, Kang; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

2014-11-01

318

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

319

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

320

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

NASA Astrophysics Data System (ADS)

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

Limpens, Juul; Nilsson, Mats

2014-05-01

321

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

322

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

323

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

324

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

325

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

326

The Perils of Partition: Difficulties in Retrieving Magma Compositions from Chemically Equilibrated Basaltic Meteorites  

NASA Technical Reports Server (NTRS)

The chemical compositions of magmas can be derived from the compositions of their equilibrium minerals through mineral/magma partition coefficients. This method cannot be applied safely to basaltic rocks, either solidified lavas or cumulates, which have chemically equilibrated or partially equilibrated at subsolidus temperatures, i.e., in the absence of magma. Applying mineral/ melt partition coefficients to mineral compositions from such rocks will typically yield 'magma compositions' that are strongly fractionated and unreasonably enriched in incompatible elements (e.g., REE's). In the absence of magma, incompatible elements must go somewhere; they are forced into minerals (e.g., pyroxenes, plagioclase) at abundance levels far beyond those established during normal mineral/magma equilibria. Further, using mineral/magma partition coefficients with such rocks may suggest that different minerals equilibrated with different magmas, and the fractionation sequence of those melts (i.e., enrichment in incompatible elements) may not be consistent with independent constraints on the order of crystallization. Subsolidus equilibration is a reasonable cause for incompatible- element-enriched minerals in some eucrites, diogenites, and martian meteorites and offers a simple alternative to petrogenetic schemes involving highly fractionated magmas or magma infiltration metasomatism.

Treiman, Allan H.

1996-01-01

327

Chemical characterization of pyrolysis liquids of wood-based composites and evaluation of their bio-efficiency  

Microsoft Academic Search

Pyrolysis of wood and wood-based wastes is considered to be one of the promising methods of supplying charcoal as solid material and liquids containing a number of valuable chemicals. In this study, we characterized the chemical components in the liquids from pyrolysis of solid wood and wood-based composites such as particleboard, plywood and medium density fiberboard (MDF) with phenol or

Tasuku Nakai; S. Nami Kartal; Toshimitsu Hata; Yuji Imamura

2007-01-01

328

Effects of the stage of maturation and varieties on the chemical composition of banana and plantain peels  

Microsoft Academic Search

A study of the chemical composition of six varieties of fruit peels of the banana and plantain: dessert banana (Musa AAA), plantain (Musa AAB) cooking banana (Musa ABB) and hybrid (Musa AAAB) at three stages of ripeness, was carried out in order to explore their potential applications. The varieties did not affect chemical constituents in a consistent manner. Peel of

Thomas Happi Emaga; Rado Herinavalona Andrianaivo; Bernard Wathelet; Jean Tchango Tchango; Michel Paquot

2007-01-01

329

Chapter 9. Utilizing mineralogical and chemical information in PTFs (A. Bruand) Soil structure is known to reflect mineralogical composition of clay fraction and soil  

E-print Network

is known to reflect mineralogical composition of clay fraction and soil chemical composition. Because soil hydraulic properties are likely to depend on soil structure, chemical and mineralogical composition haveChapter 9. Utilizing mineralogical and chemical information in PTFs (A. Bruand) Soil structure

Paris-Sud XI, Université de

330

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

NASA Astrophysics Data System (ADS)

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

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

331

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

332

Chemical composition, stratigraphy, and depositional environments of the Black River Group (Middle Ordovician), southwestern Ohio.  

USGS Publications Warehouse

The chemical composition and stratigraphy of the Black River Group in southwestern Ohio were studied. Chemical analyses were done on two cores of the Black River from Adams and Brown Counties, Ohio. These studies show that substantial reserves of high-carbonate rock are present in the Black River at depths of less than 800 ft, in proximity to Cincinnati and the Ohio River. Stratigraphic studies show that the Black River Group has eight marker beds in its middle and upper portions and three distinct lithologic units in its lower portion; these marker beds and units are present throughout southwestern Ohio. The Black River Group correlates well with the High Bridge Group of Kentucky. Depositional environments of the Black River are similar to those of the High Bridge and to present-day tidal flats in the Bahamas.-Author

Smith, D.A.

1981-01-01

333

[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

334

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

335

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

336

Seasonal Changes in Chemical Composition and Nutritive Value of Native Forages in a Spruce-Hemlock Forest, Southeastern Alaska.  

National Technical Information Service (NTIS)

Twenty-two forages from Admirality Island, southeastern Alaska, were monitored bimonthly for one year to assess seasonal changes in their chemical composition: neutral detergent fiber, acid detergent fiber, cellulose, lignin/cutin, invitro-dry-matter dige...

T. A. Hanley, J. D. McKendrick

1983-01-01

337

Alumina fiber/alumina matrix composites prepared by a chemical vapor infiltration technique  

SciTech Connect

Ceramic/ceramic composites made of alumina fibers embedded in an alumina matrix were obtained from fibrous alumina preforms (fiber volume = 0.12 to 0.40) using a chemical vapor infiltration technique based on gaseous alumina precursors (AlCl3-H2-CO2). Low deposition temperatures (950 to 1000 C) and total pressures (2 to 3 kPa) must be used to preferentially deposit alumina within the pores rather than on the external surface of the preform. Different fiber orientations were studied: i.e. randomly oriented short fibers and one- and two-dimensional preforms. Densification was performed down to residual open porosity of the order of 10 to 15 percent. For a one-dimensional alpha-alumina fiber composite (residual porosity about 10 percent), flexural strengths of 250 MPa and about 100 MPa were obtained at room temperature and 1200 C, respectively. Most composites exhibited brittle failure at room temperature. 20 references.

Colmet, R.; Lhermitte-Sebire, I.; Naslain, R.

1986-04-01

338

Thermal expansion of laminated, woven, continuous ceramic fiber/chemical-vapor-infiltrated silicon carbide matrix composites  

NASA Technical Reports Server (NTRS)

Thermal expansions of three two-dimensional laminate, continuous fiber/chemical-vapor-infiltrated silicon carbide matrix composites reinforced with either FP-Alumina (alumina), Nextel (mullite), or Nicalon (Si-C-O-N) fibers are reported. Experimental thermal expansion coefficients parallel to a primary fiber orientation were comparable to values calculated by the conventional rule-of-mixtures formula, except for the alumina fiber composite. Hysteresis effects were also observed during repeated thermal cycling of that composite. Those features were attributed to reoccurring fiber/matrix separation related to the micromechanical stresses generated during temperature changes and caused by the large thermal expansion mismatch between the alumina fibers and the silicon carbide matrix.

Eckel, Andrew J.; Bradt, Richard C.

1990-01-01

339

Chemical lasers  

NASA Astrophysics Data System (ADS)

The application and the advances of quantum electronics, specifically, of optical quantum generators lasers is reviewed. Materials are cut, their surfaces are machined, chemical transformations of substances are carried out, surgical operations are performed, data are transmitted, three dimensional images are produced and the content of microimpurities, in the atmosphere, are analyzed by use of a beam. Laser technology is used in conducting investigations in the most diverse fields of the natural and technical sciences from controlled thermonuclear fusion to genetics. Many demands are placed on lasers as sources of light energy. The importance of low weight, compactness of the optical generator and the efficiency of energy conversion processes is emphasized.

Khariton, Y.

1984-08-01

340

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.

2011-05-18

341

Chemical synthesis of poly(aniline-co-o\\/m-toluidine)\\/V 2O 5 nano composites and their characterizations  

Microsoft Academic Search

Chemical oxidative polymerization of aniline (ANI) and o\\/m-toluidine (OT or MT) and their nano composites at different experimental conditions were performed using peroxydisulfate (PDS) as a lone chemical initiator and V2O5 as a host material in an aqueous HCl medium at 45°C under nitrogen atmosphere. The nano composites were synthesized under different experimental conditions and were characterized by Fourier transform

J. Juliet Latha Jeyakumari; A. Yelilarasi; B. Sundaresan; V. Dhanalakshmi; R. Anbarasan

2010-01-01

342

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

343

Chemical composition and biological functions of Listeria monocytogenes cell wall preparations.  

PubMed Central

A crude Listeria cell wall fraction, a purified fraction (PF) with demonstrated biological activity, as well as a third fraction of base-hydrolyzed PF (BHPF) were analyzed for chemical composition and activities not previously described. Listeria cell wall fraction and PF contained significant quantities of lipid, whereas BHPF was lipid depleted. Fatty acid compositions were typical of gram-positive bacteria. PF and BHPF were depleted in protein. Alanine, glutamic acid, diaminopimelic acid, glucosamine, and muramic acid were found in all fractions, in enhanced concentration in PF and BHPF, and with molar ratios typical of bacterial peptidoglycans. Major neutral sugars were rhamnose, ribose, ribitol, and glucose. The concentrations of rhamnose, ribose, and glucose were increased in BHPF. Differences in chemical composition of the fractions reflected differences in their biological activities: Listeria cell wall fraction induced resistance to Listeria infection, whereas PF did not. Mitogenic and adjuvant activities were demonstrated for Listeria cell wall fraction and PF but were lost in BHPF. BHPF retained the ability to induce macrophage-mediated tumoricidal activity and decrease resistance to Listeria infection. PMID:6404818

Hether, N W; Campbell, P A; Baker, L A; Jackson, L L

1983-01-01

344

Change in the surface morphology and chemical composition of some oxide crystals under UV laser irradiation  

SciTech Connect

The effect of the 248-nm KrF and 355-nm YAG:Nd{sup 3+} laser radiation on the surface morphology and chemical composition of SrTiO{sub 3}, Sr{sub 2}RuO{sub 4}, PbMoO{sub 4}, LiNbO{sub 3}, Y{sub 3}Al{sub 5}O{sub 12}, and Al{sub 2}O{sub 3} crystals has been studied. A relationship between the laser energy density on the sample surface and the surface roughness caused by the irradiation is determined. A technique for determining exactly the geometric surface characteristics is proposed. The effect of the surface roughness on the results of energy-dispersive X-ray (EDX) microanalysis has been investigated. A method for correcting the EDX data for samples with a rough surface has been developed. It is shown that the small variation in the composition of PbMoO{sub 4}, LiNbO{sub 3}, Y{sub 3}Al{sub 5}O{sub 12}, and Al{sub 2}O{sub 3} samples after laser irradiation can be explained by the measurement error, related to the change in the surface roughness. At the same time, the irradiation of SrTiO{sub 3} and Sr{sub 2}RuO{sub 4} crystals by a YAG:Nd laser changes the chemical composition of their surface layers. (interaction of laser radiation with matter)

Kuzanyan, A S; Badalyan, G R; Kuzanyan, V S; Nikogosyan, V R; Pilosyan, S Kh; Nesterov, V M

2011-07-31

345

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

346

Adhesion and Wettability Characteristics of Chemically Modified Banana Fibre for Composite Manufacturing  

Microsoft Academic Search

In this work banana fibre was chemically modified using various chemical agents. The surface energy of the fibre is an important parameter and one which governs the interaction of fibre with polymeric matrices. This paper describes the influence of various chemical treatments on the surface energy of the banana fibre investigated by contact angle measurements, spectroscopic analysis and surface morphology

K. N. Indira; Y. Grohens; C. Baley; S. Thomas; K. Joseph; L. A. Pothen

2011-01-01

347

Chemical Composition Dependent Elastic Strain in AlGaN Epilayers  

NASA Astrophysics Data System (ADS)

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

Wang, Huan; Yao, Shu-De

2014-10-01

348

Effect of stainless steel chemical composition on brazing ability of filler metal  

NASA Astrophysics Data System (ADS)

Many kinds of stainless steel have been used in the engineering field. So it is necessary to investigate the effect of SUS chemical compositions on the brazing ability of filler metal. In this study, SUS315J containing Cr, Ni, Si, Cu, and Mo was employed as a base metal. Excellent spreading ability of the molten nickel-based brazing filler on SUS315J was obtained as compared with that on SUS316. Copper and silicon influenced the significant spreading ability of the filler.

Miyazawa, Yasuyuki; Ohta, Kei; Nishiyama, Akira

2014-08-01

349

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

PubMed

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

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

2011-01-01

350

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; Jantschi, Lorentz; Bolboaca, Sorana D.

2008-01-01

351

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

PubMed Central

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 13C 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

2009-01-01

352

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

353

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

354

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

NASA Astrophysics Data System (ADS)

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

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

355

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

E-print Network

for the degree af ~ OF SCIEN;E Angust, 1959 Eager Snbgeot s Agronosy THE EFFECT OF SULFATE SULFUR ON THE IIELD AND CHEMICAL COMPOSITION OF OATS, VETCH~ AND TURNIPS A Thesis By JACK RCOERS GIPSON . j, ' / g / ~ / g/ g/ g/ / &e 8/ ~ / Approved... of sulfate sulfur per acre in the top six inches of soil prior to planting. 7 Table 2 The pH and pounds per acre of F20~, K 0, and CaO as de- termined by the Texas Agricultural Extension Servioe Soil Testing Laboratory. 8 Table 3 Treatments used...

Gipson, Jack Rogers

2012-06-07

356

Tracing the evolution of NGC6397 through the chemical composition of its stellar populations  

Microsoft Academic Search

With the aim to constrain multiple populations in the metal-poor globular\\u000acluster NGC6397, we analyse and discuss the chemical compositions of a large\\u000anumber of elements in 21 red giant branch stars. High-resolution spectra were\\u000aobtained with the FLAMES\\/UVES spectrograph on VLT. We have determined non-LTE\\u000aabundances of Na and LTE abundances for the remaining 21 elements, including O,\\u000aMg,

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

2010-01-01

357

Morphological and photoluminescence study of chemically synthesized Al2O3 polythiophene composite  

NASA Astrophysics Data System (ADS)

Undoped and Al2O3 doped Polythiophene were synthesized by chemical route method. All the samples were characterized by fourier transform infra-red spectroscopy. Scanning electron microscopy shows the formation of spherical like particles for Al2O3 polythiophene composite and its size decreases continuously as Al2O3 doping percentage increases. Photoluminescence spectra were recorded at excitation wavelength 325 nm. All the samples have mainly two visible peaks at 462 and 490 nm respectively. The PL of present sample may have several optoelectronic applications like organic light emitting diodes (OLEDs), and photovoltaic cell etc.

Tripathi, Akhilesh; Bahadur, Indra; Shukla, R. K.

2014-04-01

358

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

359

Chemical composition and physicochemical properties of green banana (Musa acuminata x balbisiana Colla cv. Awak) flour.  

PubMed

Flour was prepared from peeled and unpeeled banana Awak ABB. Samples prepared were subjected to analysis for determination of chemical composition, mineral, dietary fibre, starch and total phenolics content, antioxidant activity and pasting properties. In general, flour prepared from unpeeled banana was found to show enhanced nutrition values with higher contents of mineral, dietary fibre and total phenolics. Hence, flour fortified with peel showed relatively higher antioxidant activity. On the other hand, better pasting properties were shown when banana flour was blended with peel. It was found that a relatively lower pasting temperature, peak viscosity, breakdown, final viscosity and setback were evident in a sample blended with peel. PMID:19449278

Haslinda, W H; Cheng, L H; Chong, L C; Noor Aziah, A A

2009-01-01

360

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

361

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

362

Chemical Analyses  

NASA Technical Reports Server (NTRS)

As a preliminary study on the effects of chemical aging of polymer materials MERL and TRI have examined two polymeric materials that are typically used for offshore umbilical applications. These two materials were Tefzel, a copolymer of ethylene and tetrafluoroethylene, and Coflon, polyvinylidene fluoride. The Coflon specimens were cut from pipe sections and exposed to H2S at various temperatures and pressures. One of these specimens was tested for methane permeation, and another for H2S permeation. The Tefzel specimens were cut from .05 mm sheet stock material and were exposed to methanol at elevated temperature and pressure. One of these specimens was exposed to methanol permeation for 2 days at 100 C and 2500 psi. An additional specimen was exposed to liquid methanol for 3 days at 150 C and 15 Bar. Virgin specimens of each material were similarly prepared and tested.

Bulluck, J. W.; Rushing, R. A.

1994-01-01

363

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

SciTech Connect

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

C. M. Frazee; J. D. Christian

2004-02-01

364

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

365

Chemical composition of boulder-2 rocks and soils, Apollo 17, Station 2  

NASA Technical Reports Server (NTRS)

The bulk and trace element composition of five small samples from four rocks is remarkably similar. This result indicates that the metaclastic rocks studied are relatively uniform in their chemical composition. The elemental abundances found in the study are presented in two tables and the implications of the data are considered, giving attention to siderophiles, atmophile elements, and questions of element correlations. The 'dark mantle' valley soil 75081 at Camelot Crater is low in siderophiles. Since the soil is low in alkalis, a derivation from low-alkali mare basalt is suggested. The identical volatile contents in the surface soil 72461 and the 4 cm depth soil 72441 under a 0.7 m boulder argue against any surficial volatization by galactic and solar particles.

Laul, J. C.; Schmitt, R. A.

1974-01-01

366

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

PubMed

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) (I(COM)), 1473 cm(-1) (I(COD)), 961 cm(-1) (I(HAP)) and 1282 cm(-1) (I(UA)) were used. PMID:23816485

Selvaraju, R; Raja, A; Thiruppathi, G

2013-10-01

367

Chemical composition, quality and histochemical characteristics of individual dromedary camel (Camelus dromedarius) muscles.  

PubMed

This study characterized the chemical composition, quality and histological traits of six muscles from 10 dromedary carcasses. There were significant differences in moisture, fat, protein, mineral, saturated and unsaturated fatty acid contents between muscles. The longissimus thoracis (LT) had the highest cooking loss (33.5%) and triceps brachii (TB) the lowest (29.2%). The shear force value of semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) were significantly higher than infraspinatus (IS), TB and LT. The LT had significantly higher values for L*, a*, b* than ST. The SM had the lowest MFI (65.3), while IS had the highest value (75.8). The ST significantly had the highest and lowest proportions of Type I and Type IIA muscle fibers, respectively than other muscles. This study indicated that composition, quality, and histochemical parameters varied among camel muscles and the knowledge of this variation allows for better marketing and processing of camel meat. PMID:23273465

Kadim, I T; Al-Karousi, A; Mahgoub, O; Al-Marzooqi, W; Khalaf, S K; Al-Maqbali, R S; Al-Sinani, S S H; Raiymbek, G

2013-03-01

368

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

369

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

370

Chemical composition and antimicrobial activity of essential oil of Heracleum rigens.  

PubMed

The essential oil was extracted from the seeds of Heracleum rigens by hydrodistillation and a total of twenty compounds accounting for 98.5% of the total oil composition were identified. Physicochemical properties and chemical composition of the oil was determined by a combination GC/FID and GC/MS analysis. The major compounds identified were bornyl acetate (51.2%), alpha-pinene (22.6%), limonene (9.62%), octyl acetate (3.94%), rho-cymene (2.85%) and gamma-terpinene (1.93%). The antimicrobial activity of the oil was screened by the disc diffusion method against nine pathogenic bacterial strains. Maximum antimicrobial activity was noted against Klebsiella pneumonia and Bacillus subtillis. This investigation corroborates the traditional claim of H. rigens as an effective antimicrobial agent. PMID:22908589

Jagannath, Nataraj; Ramakrishnaiah, Hanumanthaiah; Krishna, Venkatarangaiah; Gowda, Prameela Javarayi

2012-07-01

371

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

372

The chemical durability of glass and graphite-glass composite doped with cesium oxide  

NASA Astrophysics Data System (ADS)

The role of temperature in determining the chemical stability of a waste form, as well as its leach rate, is very complex. This is because the dissolution kinetics is dependent both on temperature and possibility of different rate-controlling mechanisms that appear at different temperature regions. The chemical durability of Alumina-Borosilicate Glass (ABG) and Glass-Graphite Composite (GGC), bearing Tristructural Isotropic (TRISO) fuel particles impregnated with cesium oxide, were compared using a static leach test. The purpose of this study is to examine the chemical durability of glass-graphite composite to encapsulate coated fuel particles, and as a possible alternative for recycling of irradiated graphite. The test was based on the ASTM C1220-98 methodology, where the leaching condition was set at a temperature varying from 298 K to 363 K for 28 days. The release of cesium from ABG was in the permissible limit and followed the Arrhenius's law of a surface controlled reaction; its activation energy (Ea) was 65.6 ± 0.5 kJ/mol. Similar values of Ea were obtained for Boron (64.3 ± 0.5) and Silicon (69.6 ± 0.5 kJ/mol) as the main glass network formers. In contrast, the dissolution mechanism of cesium from GGC was a rapid release, with increasing temperature, and the activation energy of Cs (91.0 ± 5 kJ/mol) did not follow any model related to carbon kinetic dissolution in water. Microstructure analysis confirmed the formation of Crystobalite SiO2 as a gel layer and Cs+1 valence state on the ABG surface.

Hamodi, Nasir H.; Abram, Timothy J.; Lowe, Tristan; Cernik, Robert J.; López-Honorato, Eddie

2013-01-01

373

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

374

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

375

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

PubMed Central

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

Teixeira, Erica Weinstein; Message, Dejair; Negri, Giuseppina; Stringheta, Paulo Cesar

2010-01-01

376

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

377

Chemical composition and starch digestibility in flours from Polish processed legume seeds.  

PubMed

The study was undertaken to determine the effect of various treatments, i.e. cooking after soaking, freezing after cooking and storage at a low temperature (-18°C, 21days), and autoclaving, of Polish cultivars of bean, pea and lentil seeds on the chemical composition and starch digestibility of the resultant flours. The cooking of seeds caused a significant decrease in contents of ash (by 11-48%), polyphenols (by 10-70%) and protein (to 19%) in flours made of bean. In addition, analyses demonstrated significantly decreased contents of resistant starch, RS (by 61-71%) and slowly digestible starch, SDS (by 56-84%). Storage of frozen seeds resulted in insignificant changes in the chemical composition, and in increased contents of both RS and SDS. The flours produced upon the autoclaving process were characterized by similar changes in the contents of ash and protein as in cooked seeds, yet losses of polyphenols were lower and, simultaneously, contents of RS and SDS were higher. All the analyzed flours were shown to be characterized by a reduced content of amylose in starch, which might have affected its digestibility. This was indicated by a strict negative correlation reported between the value of the starch digestion index (SDRI) and amylose content of starch (r=0.84, p>0.05). PMID:22953824

Piecyk, Ma?gorzata; Wo?osiak, Rafa?; Dru?ynska, Beata; Worobiej, Elwira

2012-12-01

378

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

379

On the Binary Helium Star DY Centauri: Chemical Composition and Evolutionary State  

NASA Astrophysics Data System (ADS)

DY Cen has shown a steady fading of its visual light by about one magnitude in the last 40 yr, suggesting a secular increase in its effective temperature. We have conducted non-local thermodynamic equilibrium (LTE) and LTE abundance analyses to determine the star's effective temperature, surface gravity, and chemical composition using high-resolution spectra obtained over two decades. The derived stellar parameters for three epochs suggest that DY Cen has evolved at a constant luminosity and has become hotter by about 5000 K in 23 yr. We show that the derived abundances remain unchanged for the three epochs. The derived abundances of the key elements, including F and Ne, are as observed for the extreme helium stars resulting from a merger of a He white dwarf with a C-O white dwarf. Thus DY Cen by chemical composition appears to also be a product of a merger of two white dwarfs. This appearance seems to be at odds with the recent suggestion that DY Cen is a single-lined spectroscopic binary.

Pandey, Gajendra; Kameswara Rao, N.; Jeffery, C. Simon; Lambert, David L.

2014-10-01

380

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

USGS Publications Warehouse

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

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

1977-01-01

381

On the binary helium star DY Centauri: Chemical composition and evolutionary state  

E-print Network

DY Cen has shown a steady fading of its visual light by about 1 magnitude in the last 40 years suggesting a secular increase in its effective temperature. We have conducted non-LTE and LTE abundance analyses to determine the star's effective temperature, surface gravity, and chemical composition using high-resolution spectra obtained over two decades. The derived stellar parameters for three epochs suggest that DY Cen has evolved at a constant luminosity and has become hotter by about 5000 K in 23 years. We show that the derived abundances remain unchanged for the three epochs. The derived abundances of the key elements, including F and Ne, are as observed for the extreme helium stars resulting from a merger of an He white dwarf with a C-O white dwarf. Thus, DY Cen by chemical composition appears to be also a product of a merger of two white dwarfs. This appearance seems to be at odds with the recent suggestion that DY Cen is a single-lined spectroscopic binary.

Pandey, Gajendra; Jeffery, C Simon; Lambert, David L

2014-01-01

382

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

PubMed Central

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

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

2005-01-01

383

Chemical composition of volatiles in Sardinian myrtle (Myrtus communis L.) alcoholic extracts and essential oils.  

PubMed

The chemical composition of the volatile fraction of myrtle (Myrtus communis L.) alcoholic extracts and essential oils from leaves and berries collected in different places in Sardinia (Italy) was studied. A simple and rapid liquid-liquid extraction method was used to isolate volatile compounds from myrtle alcoholic extracts followed by GC and GC-MS analysis allowing the detection of 24 compounds. The volatile fraction was characterized by the terpenes fraction corresponding to that of the essential oils and by a fatty acid ethyl esters fraction. The variation during extraction of the volatile fraction in alcoholic extracts of berries and leaves was evaluated. Essential oils were obtained by hydrodistillation, and the yields were on average 0.52 +/- 0.03% (v/w dried weight) and 0.02 +/- 0.00% for leaves and berries, respectively. The essential oils were analyzed by GC and GC-MS, and a total of 27 components were detected, accounting for 90.6-98.7% of the total essential oil composition. Strong chemical variability depending on the origin of the samples was observed. The major compounds in the essential oils were alpha-pinene (30.0 and 28.5%), 1,8-cineole (28.8 and 15.3%), and limonene (17.5 and 24.1%) in leaves and berries, respectively, and were characterized by the lack of myrtenyl acetate. PMID:16478269

Tuberoso, Carlo I G; Barra, Andrea; Angioni, Alberto; Sarritzu, Erika; Pirisi, Filippo M

2006-02-22

384

Chemical evolution of dense clouds  

NASA Technical Reports Server (NTRS)

Chemical processes that could determine the molecular composition of the cloud during the several stages of its evolution are considered. Reactions at the relatively interstellar densities are emphasized.

Chappelle, E. W.; Donn, B. D.; Payne, W. A., Jr.; Stief, L. J.

1972-01-01

385

Chemical Accelerators The phrase "chemical accelerators"  

E-print Network

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

Zare, Richard N.

386

Nature's chemicals and synthetic chemicals: Comparative toxicology  

Microsoft Academic Search

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

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

1990-01-01

387

Chemical composition and characterization of cellulose for Agave as a fast-growing, drought-tolerant biofuels feedstock  

E-print Network

Chemical composition and characterization of cellulose for Agave as a fast- growing, drought and feed supply. However, because agave offers high productivity with low water and nutrient demands lignocellulosic feedstock for biofuels production. Because agave composition will establish the maximum potential

California at Riverside, University of

388

The Chemical Composition of the Essential Oil and Alcoholic extract of Juniperus communis L. ssp. nana Syme  

Microsoft Academic Search

The chemical composition of the essential oil of Portuguese juniper berries (Juniperus communis L. ssp. nana Syme) was investigated by means of gas chromatography. This analysis was compared with that of an aqueous alcoholic extract of the juniper berries of similar origin. The qualitative composition of the oil and the alcoholic extract was found to be very similar. The major

A. Proença da Cunha; Odete L. R. Roque

1989-01-01

389

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

390

Predicting corn digestible and metabolizable energy content from its chemical composition in growing pigs  

PubMed Central

Background The nutrient composition of corn is variable. To prevent unforeseen reductions in growth performance, grading and analytical methods are used to minimize nutrient variability between calculated and analyzed values. This experiment was carried out to define the sources of variation in the energy content of corn and to develop a practical method to accurately estimate the digestible energy (DE) and metabolisable energy (ME) content of individual corn samples for growing pigs. Twenty samples were taken from each of five provinces in China (Jilin, Hebei, Shandong, Liaoning, and Henan) to obtain a range of quality. Results The DE and ME contents of the 100 corn samples were measured in 35.3?±?1.92 kg growing pigs (six pigs per corn sample). Sixty corn samples were used to build the prediction model; the remaining forty samples were used to test the suitability of these models. The chemical composition of each corn sample was determined, and the results were used to establish prediction equations for DE or ME content from chemical characteristics. The mean DE and ME content of the 100 samples were 4,053 and 3,923 kcal/kg (dry matter basis), respectively. The physical characteristics were determined, as well, and the results indicated that the bulk weight and 1,000-kernel weight were not associated with energy content. The DE and ME values could be accurately predicted from chemical characteristics. The best fit equations were as follows: DE, kcal/kg of DM?=?1062.68?+?(49.72?×?EE)?+?(0.54?×?GE)?+?(9.11?×?starch), with R2?=?0.62, residual standard deviation (RSD)?=?48 kcal/kg, and P?chemical measurements that may be used to predict the DE and ME content of individual corn samples. PMID:24521251

2014-01-01

391

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

NASA Astrophysics Data System (ADS)

The chemical composition of fine (PM 2.5) and coarse (PM 2.5-10) 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: Duisburg/Germany October-November 2002 (autumn), Prague/Czech Republic November 2002-January 2003 (winter), Amsterdam/Netherlands January-March 2003 (winter), Helsinki/Finland March-May 2003 (spring), Barcelona/Spain March-May 2003 (spring) and Athens/Greece June-July 2003 (summer). Aerosol samples were collected in 3+4-day periods per week ( N=14) using two identical virtual impactors (VI). All the filter samples were analysed with the same instruments to obtain particulate mass, inorganic ions, total and watersoluble elements, and elemental and organic carbon content. The campaign means of PM 2.5 and PM 2.5-10 ranged from 8.3 to 30 and 5.4 to 29 ?g m -3, respectively. The "wet and cool" seasons favoured a low coarse-to-fine particulate mass ratio (<1), whereas the ratio was high (>1) during the warmer and drier spring and summer campaigns. According to chemical mass closure, the major components in PM 2.5 were carbonaceous compounds (organic matter+elemental carbon), secondary inorganic ions and sea salt, whereas those in PM 2.5-10 were soil-derived compounds, carbonaceous compounds, sea salt and nitrate. The major and minor components together accounted for 79-106% and 77-96% of the gravimetrically measured PM 2.5 and PM 2.5-10 mass, respectively. In conclusion, the measured PM 2.5 and PM 2.5-10 in the campaigns could be reconstructed to a large extent with the help of harmonized particulate sampling and analysis of the selected chemical constituents. The health significance of the observed differences in chemical composition and emission sources between the size-segregated particulate samples will be investigated in toxicological cell and animal studies.

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

392

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

393

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

PubMed

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

Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun; Lee, Bog-Hieu

2012-02-01

394

The red alga Bonnemaisonia asparagoides regulates epiphytic bacterial abundance and community composition by chemical defence.  

PubMed

Ecological research on algal-derived metabolites with antimicrobial activity has recently received increased attention and is no longer only aimed at identifying novel natural compounds with potential use in applied perspectives. Despite this progress, few studies have so far demonstrated ecologically relevant antimicrobial roles of algal metabolites, and even fewer have utilized molecular tools to investigate the effects of these metabolites on the natural community composition of bacteria. In this study, we investigated whether the red alga Bonnemaisonia asparagoides is chemically defended against bacterial colonization of its surface by extracting surface-associated secondary metabolites and testing their antibacterial effects. Furthermore, we compared the associated bacterial abundance and community composition between B. asparagoides and two coexisting macroalgae. Surface extracts tested at natural concentrations had broad-spectrum effects on the growth of ecologically relevant bacteria, and consistent with this antibacterial activity, natural populations of B. asparagoides had significantly lower densities of epibacteria compared with the coexisting algae. Terminal restriction fragment length polymorphism analysis further showed that B. asparagoides harboured surface-associated bacteria with a community composition that was significantly different from those on coexisting macroalgae. Altogether, these findings demonstrate that B. asparagoides produces surface-bound antibacterial compounds with a significant impact on the abundance and composition of the associated bacterial community. PMID:19878319

Nylund, Göran M; Persson, Frank; Lindegarth, Mats; Cervin, Gunnar; Hermansson, Malte; Pavia, Henrik

2010-01-01

395

Helioseismic calibration of the equation of state and chemical composition in the solar convective envelope  

NASA Astrophysics Data System (ADS)

Accurate and precise measurements of solar p-mode frequencies allow sensitive diagnostics of the adiabatic exponent ?1 = (?ln p/?ln ?)S as a function of depth in the adiabatically stratified part of the solar convective envelope. The profile of the adiabatic exponent contains information about the chemical composition of the partially ionized solar plasma, and allows the accuracy of different versions of the equation of state to be assessed. We address the diagnostic potential of solar p-mode frequencies inferred from Doppler velocity measurements in the SOHO MDI `medium-l' program, the almost uninterrupted measurements covering 15 years of SOHO's operational lifetime, by examining their agreement with the seismic stratification of solar envelope models constructed with various modern versions of the equation of state (two versions of OPAL, and two versions of the SAHA-S equation of state). We use two diagnostic techniques, which complement each other: (i) direct calibration using grids of envelope models that differ in chemical composition (parametrized by the helium abundance Y and the heavy element abundance Z) and in the specific entropy in the adiabatically stratified part of the solar convective envelope; and (ii) a constrained structural helioseismic inversion. The best agreement with seismic data is provided by the recently developed SAHA-S3 equation of state. The maximum-likelihood estimates of the composition parameters Y and Z depend on the particular version of the equation of state, and may also be distorted by systematic errors in solar frequency measurements. The estimates obtained in this study are in the range of Y = 0.240-0.255 and Z = 0.008-0.013. All our results provide strong evidence in favour of low Z values, as reported from recent spectroscopic measurements.

Vorontsov, S. V.; Baturin, V. A.; Ayukov, S. V.; Gryaznov, V. K.

2013-04-01

396

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

397

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

398

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

PubMed Central

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

2013-01-01

399

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

SciTech Connect

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

Aflaki, R.; Handy, L.L.

1992-12-01

400

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

SciTech Connect

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

Aflaki, R.; Handy, L.L.

1992-12-01

401

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

NASA Astrophysics Data System (ADS)

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

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

2003-04-01

402

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

NASA Astrophysics Data System (ADS)

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

Górny, S. K.

2014-10-01

403

Chemical composition and photochemical reactivity of exhaust from aircraft turbine engines  

NASA Astrophysics Data System (ADS)

Assessment of the environmental impact of aircraft emissions is required by planners and policy makers. Seveal areas of concern are: 1. exposure of airport workers and urban residents to toxic chemicals emitted when the engines operate at low power (idle and taxi) on the ground; 2. contributions to urban photochemical air pollution of aircraft volatile organic and nitrogen oxides emissions from operations around airports; and 3. emissions of nitrogen oxides and particles during high-altitude operation. The environmental impact of chemicals emitted from jet aircraft turbine engines has not been firmly established due to lack of data regarding emission rates and identities of the compounds emitted. This paper describes an experimental study of two different aircraft turbine engines designed to determine detailed organic emissions, as well as emissions of inorganic gases. Emissions were measured at several engine power settings. Measurements were made of detailed organic composition from C1 through C17, CO, CO2, NO, NOx, and polycyclic aromatic hydrocarbons. Measurements were made using a multi-port sampling pro be positioned directly behind the engine in the exhaust exit plane. The emission measurements have been used to determine the organic distribution by carbon number and the distribution by compound class at each engine power level. The sum of the organic species was compared with an independent measurement of total organic carbon to assess the carbon mass balance. A portion of the exhaust was captured and irradiated in outdoor smog chambers to assess the photochemical reactivity of the emissions with respect to ozone formation. The reactivity of emissions from the two engines was apportioned by chemical compound class.

Spicer, C. W.; Holdren, M. W.; Riggin, R. M.; Lyon, T. F.

1994-10-01

404

Chemical composition of hoarfrost, rime and snow during a winter inversion in Utah, U.S.A  

Microsoft Academic Search

We present data on the chemical composition of hoarfrost, rime, and snow grains that accumulated during an eighteen-day long temperature inversion event in Salt Lake City, Utah in December 1985 and January 1986. Chemical analyses show that the precipitation formed during this inversion event was acidic (as low as pH 3.85) and had nitrate and sulfate contents up to 1680

Thure E. Cerling; Amanda J. Alexander

1987-01-01

405

Effects of chemical–physical pre-treatment processes on hemp fibres for reinforcement of composites and for textiles  

Microsoft Academic Search

Retted hemp fibres were treated using chemical–physical pre-treatments and the material was characterised chemically in order to evaluate the effect of the pre-treatments, respectively, wet oxidation (WO), hydrothermal treatment (HT) and steam explosion (STEX). Process variables were addition of base and oxidant. These treatments were performed to make fibres that are useful as reinforcement in composite materials and for textiles.

Anne Belinda Thomsen; Anders Thygesen; Vibeke Bohn; Kristina Vad Nielsen; Bodil Pallesen; Michael Søgaard Jørgensen

2006-01-01

406

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

407

Essential oil of Indian propolis: chemical composition and repellency against the honeybee Apis florea.  

PubMed

Hitherto unknown biological properties and the chemical composition of the essential oil isolated from propolis of Indian origin were established. GC/MS Analysis of the essential oil revealed the presence of 32 constituents, of which ten were major compounds, nine had intermediate contents, and 13 were minor compounds. With the exception of six minor constituents, that could not be identified, their identification was based on the comparison of their mass spectra and Kovats retention indices with those listed in the NIST and Wiley mass spectral libraries. Their structural assignment was confirmed by GC/MS co-injection of the essential oil with authentic compounds. Quantification of the components was done by GC-FID analyses. Moreover, the essential oil was shown to possess repellent activity against the honeybee Apis florea. The activity was found to be dose dependent. The average repellency (?R) increased with increasing essential-oil concentration up to 24??g/ml and remained constant for the formulation with the higher concentration. These findings established the chemical constitution of the essential oil and might be useful to beekeepers for the improvement of the bee management. PMID:23576351

Naik, Dattatraya G; Vaidya, Harshada S; Namjoshi, Tejas P

2013-04-01

408

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

SciTech Connect

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

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

1992-12-01

409

Chemical composition and antioxidant, antimicrobial, and antifungal activities of the essential oil of Achillea ligustica all.  

PubMed

The chemical composition of the essential oil from flowering tops of Achillea ligustica All. was studied. Samples were collected in different localities of Sardinia (Italy) and hydrodistilled both with Clevenger-type and with simultaneous distillation-extraction apparatus. The yields ranged between 0.88 +/- 0.06 and 0.43 +/- 0.02% (vol/dry wt). The essential oils were analyzed by GC-MS, and a total of 96 components were detected. From a qualitative point of view, irrelevant differences between samples were observed. Strong chemical variability depending on the origin of the samples was observed. The major compounds found were santolina alcohol (6.7-21.8%, for the first time detected in A. ligustica), borneol (3.4-20.8%), sabinol (2.1-15.5%), trans-sabinyl acetate (0.9-17.6%), alpha-thujone (0.4-25.8%), and, among sesquiterpenes, viridiflorol (0.7-3.6%). No significant differences were detected between essential oils extracted by hydrodistillation and simultaneous distillation-extraction with CH2Cl2 and n-hexane. Antioxidant activity as DPPH radical scavenging activity was expressed in TEAC and ranged between 0.40 and 0.88 mmol/L. The antimicrobial and antifungal activities were investigated on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Penicillium commune, Fusarium oxysporum, Rizoctonia solani, and Aspergillus flavus, showing low activity. PMID:16366708

Tuberoso, Carlo I G; Kowalczyk, Adam; Coroneo, Valentina; Russo, Maria Teresa; Dessì, Sandro; Cabras, Paolo

2005-12-28

410

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

411

Chemical composition measurements of the atmosphere of Jupiter with the Galileo Probe mass spectrometer  

NASA Technical Reports Server (NTRS)

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 source of the mass spectrometer through capillary leaks or of gas, which had been chemically processed to enhance the sensitivity of the measurement to trace species or noble gases. The analysis of this data set continues to be refined based on supporting laboratory studies on an engineering unit. The mixing ratios of the major constituents of the atmosphere hydrogen and helium have been determined as well as mixing ratios or upper limits for several less abundant species including: methane, water, ammonia, ethane, ethylene, propane, hydrogen sulfide, neon, argon, krypton, and xenon. Analysis also suggests the presence of trace levels of other 3 and 4 carbon hydrocarbons, or carbon and nitrogen containing species, phosphine, hydrogen chloride, and of benzene. The data set also allows upper limits to be set for many species of interest which were not detected. Isotope ratios were measured for 3He/4He, D/H, 13C/12C, 20Ne/22Ne, 38Ar/36Ar and for isotopes of both Kr and Xe.

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

1998-01-01

412

Mumijo Traditional Medicine: Fossil Deposits from Antarctica (Chemical Composition and Beneficial Bioactivity)  

PubMed Central

Mumijo is a widely used traditional medicine, especially in Russia, Altai Mountains, Mongolia, Iran Kasachstan and in Kirgistan. Mumijo preparations have been successfully used for the prevention and treatment of infectious diseases; they display immune-stimulating and antiallergic activity as well. In the present study, we investigate the chemical composition and the biomedical potential of a Mumijo(-related) product collected from the Antarctica. The yellow material originates from the snow petrels, Pagodroma nivea. Extensive purification and chemical analysis revealed that the fossil samples are a mixture of glycerol derivatives. In vitro experiments showed that the Mumijo extract caused in cortical neurons a strong neuroprotective effect against the apoptosis-inducing amyloid peptide fragment ?-fragment 25–35 (A?25–35). In addition, the fraction rich in glycerol ethers/wax esters displayed a significant growth-promoting activity in permanent neuronal PC12 cells. It is concluded that this new Mumijo preparation has distinct and marked neuroprotective activity, very likely due to the content of glycerol ether derivatives. PMID:18996940

Aiello, Anna; Fattorusso, Ernesto; Menna, Marialuisa; Vitalone, Rocco; Schröder, Heinz C.; Müller, Werner E. G.

2011-01-01

413

Chemical composition of atmospheric precipitation on the south of Ukraine (Crimea)  

NASA Astrophysics Data System (ADS)

The data of long monitoring of volume and chemical content of atmospheric precipitation in steppe Crimea near to the large plantations of fruit orchards are given The purpose of researches was detection of acid deposits establishment of connection them dI with chemical structure for the operative tracking behind a condition of air It was established that the sum of precipitations for year was increased basically at the summer deposits The annual volume-weighted logarithmic range of dI values were 4 83-5 73 in precipitation There were more less values in a cold season than in warm one The absolute minimum was equal 3 82 For the researched period mean dI values of atmospheric precipitation in a cold season gradually raised and in warm - was reduced and has reached the minimum in 2000-2001 years It resulted in damages of fruit plants during long term rains in vegetation period The dominant anion in atmospheric precipitation was SO 4 2- which content basically determined of them acidification The important role in this process also belongs to ions NO 3 - and Cl - Mean seasons concentrations of these ions tend to increase It probably may be connected both to distant distribution of emission and with local anthropogenic activity In connection with an establishment of atmospheric precipitation acidification and also incidental and casual phenomenon there is a necessity of their composition monitoring for agricultural areas near to the large fruit plantations for big number years during whole year

Klymenko, O.; Klymenko, M.

414

The Chemical Composition of Comets—Emerging Taxonomies and Natal Heritage  

NASA Astrophysics Data System (ADS)

Cometary nuclei contain the least modified material from the formative epoch of our planetary system, and their compositions reflect a range of processes experienced by material prior to its incorporation in the cometary nucleus. Dynamical models suggest that icy bodies in the main cometary reservoirs (Kuiper Belt, Oort Cloud) formed in a range of environments in the protoplanetary disk, and (for the Oort Cloud) even in disks surrounding neighboring stars of the Sun's birth cluster. Photometric and spectroscopic surveys of more than 100 comets have enabled taxonomic groupings based on free radical species and on crystallinity of rocky grains. Since 1985, new surveys have provided emerging taxonomies based on the abundance ratios of primary volatiles. More than 20 primary chemical species are now detected in bright comets. Measurements of nuclear spin ratios (in water, ammonia, and methane) and of isotopic ratios (D/H in water and HCN; 14N/15N in CN and HCN) have provided critical insights on factors affecting formation of the primary species. The identification of an abundant product species (HNC) has provided clear evidence of chemical production in the inner coma. Parallel advances have occurred in astrochemistry of hot corinos, circumstellar disks, and dense cloud cores. In this review, we address the current state of cometary taxonomy and compare it with current astrochemical insights.

Mumma, Michael J.; Charnley, Steven B.

2011-09-01

415

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

SciTech Connect

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

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

2011-04-20

416

Chemical composition of Hypericum richeri subsp. grisebachii essential oil from Croatia.  

PubMed

The aerial parts of Hypericum richeri Vill. subsp. grisebachii (Boiss.) Nyman were collected from two different locations in Croatia and subjected to hydrodistillation. GC/FID and GC/MS analysis of the isolated essential oils revealed 64 compounds representing 94.7% and 98.2% of the total oils. Predominant constituents in both samples were: germacrene D (10.90%; 6.0%), bicyclogermacrene (4.7%; 3.5%), alpha-pinene (6.8%; 6.9%), beta-pinene (8.1%; 5.1%), decanoic acid (4.5%; 6.8%), beta-caryophyllene (3.3%; 7.5%), delta-cadinene (7.0%; 4.4%), spathulenol (6.0%; 9.5%) and tetracosane (3.1%; 5.8%). Comparison of both samples revealed similarity in the chemical composition with minor fluctuations of constituent percentages. The chemical profile of Croatian oils was in general similar to those reported for other geographic areas regarding major mono- and sesquiterpene constituents. However, spathulenol, delta-cadinene and bicyclogermacrene were more abundant in Croatian oils. The presence of decanoic acid (4.5%; 6.8%) in Croatian oils was the major difference between acids and fatty acids derivatives. Higher abundance of alkanes (particularly tetracosane and docosane) was also noticed. PMID:23513737

Jerkovi?, Igor; Marasovi?, Maja; Marijanovi?, Zvonimir; Pilepi?, Kroata Hazler; Males, Zeljan; Milos, Mladen

2013-02-01

417

Chemical modification of jute fibers for the production of green-composites.  

PubMed

Natural fiber reinforced composites is an emerging area in polymer science. Fibers derived from annual plants are considered a potential substitute for non-renewable synthetic fibers like glass and carbon fibers. The hydrophilic nature of natural fibers affects negatively its adhesion to hydrophobic polymeric matrices. To improve the compatibility between both components a surface modification has been proposed. The aim of the study is the chemical modification of jute fibers using a fatty acid derivate (oleoyl chloride) to confer hydrophobicity and resistance to biofibers. This reaction was applied in swelling and non-swelling solvents, pyridine and dichloromethane, respectively. The formation of ester groups, resulting from the reaction of oleoyl chloride with hydroxyl group of cellulose were studied by elemental analysis (EA) and Fourier Transform infrared spectroscopy (FTIR). The characterization methods applied has proved the chemical interaction between the cellulosic material and the coupling agent. The extent of the reactions evaluated by elemental analysis was calculated using two ratios. Finally electron microscopy was applied to evaluate the surface changes of cellulose fibers after modification process. PMID:17320283

Corrales, F; Vilaseca, F; Llop, M; Gironès, J; Méndez, J A; Mutjè, P

2007-06-18

418

Chemical composition and functional properties of native chestnut starch (Castanea sativa Mill).  

PubMed

Starch isolation methods can change their physico-chemical and functional characteristics hindering the establishment of a starch-food functionality relation. A simple high yield and soft isolation method was applied for chestnut (Castanea sativa Mill) starch consisting in steeping and fruit disintegration in a 25 mM sodium bisulfite solution and purification by sedimentation. Starch integrity, physico-chemical composition, morphology and functional properties were determined, being observed significant differences from previous described methods for chestnut starch isolation. The X-ray pattern was of B-type, with a degree of crystallinity ranging from 51% to 9%, dependent on the starch moisture content. The onset, peak, and conclusion gelatinization temperatures were 57.1°C, 61.9°C and 67.9°C, respectively. Total amylose content was 26.6%, and there was not found any evidence for lipid complexed amylose. Swelling power at 90°C was 19 g/g starch, and the amount of leached amylose was 78% of the total amylose content. Native chestnut starch presents a type B pasting profile similar to corn starch but with a lower gelatinization (56.1°C) and peak viscosity (79.5°C) temperatures, making native chestnut starch a potential technological alternative to corn starch, especially in application where lower processing temperatures are needed. PMID:23544579

Cruz, Bruno R; Abraão, Ana S; Lemos, André M; Nunes, Fernando M

2013-04-15

419

Physical, chemical and flavour quality of non-fat yogurt as affected by a ?-glucan hydrocolloidal composite during storage  

Microsoft Academic Search

In this study, a possible use of ?-glucan hydrocolloidal composite as a fat replacer in the manufacture of non-fat yogurts was investigated. The yogurts with added ?-glucan composite were compared with non-fat yogurt without addition of ?-glucan composite and the samples were analysed for physical, chemical and sensory attributes after 1, 7 or 15d of storage. Fat and protein contents

N. Sahan; K. Yasar; A. A. Hayaloglu

2008-01-01

420

Particle Emissions from a Marine Engine: Chemical Composition and Aromatic Emission Profiles under Various Operating Conditions.  

PubMed

The chemical composition of particulate matter (PM) emissions from a medium-speed four-stroke marine engine, operated on both heavy fuel oil (HFO) and distillate fuel (DF), was studied under various operating conditions. PM emission factors for organic matter, elemental carbon (soot), inorganic species and a variety of organic compounds were determined. In addition, the molecular composition of aromatic organic matter was analyzed using a novel coupling of a thermal-optical carbon analyzer with a resonance-enhanced multiphoton ionization (REMPI) mass spectrometer. The polycyclic aromatic hydrocarbons (PAHs) were predominantly present in an alkylated form, and the composition of the aromatic organic matter in emissions clearly resembled that of fuel. The emissions of species known to be hazardous to health (PAH, Oxy-PAH, N-PAH, transition metals) were significantly higher from HFO than from DF operation, at all engine loads. In contrast, DF usage generated higher elemental carbon emissions than HFO at typical load points (50% and 75%) for marine operation. Thus, according to this study, the sulfur emission regulations that force the usage of low-sulfur distillate fuels will also substantially decrease the emissions of currently unregulated hazardous species. However, the emissions of soot may even increase if the fuel injection system is optimized for HFO operation. PMID:25202837

Sippula, O; Stengel, B; Sklorz, M; Streibel, T; Rabe, R; Orasche, J; Lintelmann, J; Michalke, B; Abbaszade, G; Radischat, C; Gröger, T; Schnelle-Kreis, J; Harndorf, H; Zimmermann, R

2014-10-01

421

Fast Time Response Measurements of Aerosol Composition by Chemical Ionization Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Fast and accurate measurements of atmospheric aerosol composition is an important part of quantifying and understanding atmospheric pollution and its consequences. Such data can be used for studies of regional haze analysis, development of atmospheric models, atmospheric aerosol source apportionment and aerosol and gas interactions. This presentation describes the development of a new technique for the measurement of atmospheric aerosol composition. A negative ion Chemical Ionization Mass Spectrometry (CIMS) method has been used to perform 1 Hz aerosol composition measurements. A heated inlet is used to evaporate ambient aerosol with subsequent detection of the evolved gases. Two reagent ions, bromide and nitrate, have been used to selectively detect acidic components of the aerosols such as sulfate, nitrate, malonate, and oxalate. The CIMS sulfate measurements in ambient air were compared with a Particle into Liquid Sampler (PILS). These tests showed a high degree of correlation between the measurements and strongly suggest that the CIMS can measure sulfate with a high degree of selectivity and sensitivity. Further tests suggest that CIMS method may be able to also perform selective measurements of a few strong organic acids such as oxalic.

Hecobian, A.; Thompson, A.; Tanner, D.; Peltier, R.; Weber, R.; Huey, G.

2005-12-01

422

A model for studying the composition and chemical effects of stratospheric aerosols  

NASA Technical Reports Server (NTRS)

We developed polynomial expressions for the temperature dependence of the mean binary and water activity coefficients for H2SO4 and HNO3 solutions. These activities were used in an equilibrium model to predict the composition of stratospheric aerosols under a wide range of environmental conditions. For typical concentrations of H2O, H2SO4, HNO3, HCl, HBr, HF, and HOCl in the lower stratosphere, the aerosol composition is estimated as a function of the local temperature and the ambient relative humidity. For temperatures below 200 K, our results indicate that (1) HNO3 contributes a significant mass fraction to stratospheric aerosols, and (2) HCl solubility is considerably affected by HNO3 dissolution into sulfate aerosols. We also show that, in volcanically disturbed periods, changes in stratospheric aerosol composition can significantly alter the microphysics that leads to the formation of polar stratospheric clouds. The effects caused by HNO3 dissolution on the physical and chemical properties of stratospheric aerosols are discussed.

Tabazadeh, Azadeh; Turco, Richard P.; Jacobson, Mark Z.

1994-01-01

423

Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors  

NASA Technical Reports Server (NTRS)

Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.

Ryan, M. A.; Lewis, N. S.

2001-01-01

424

Chemical Composition of Comet C/2007 N3 (Lulin): Another ''Atypical'' Comet  

NASA Astrophysics Data System (ADS)

We measured the volatile chemical composition of comet C/2007 N3 (Lulin) on three dates from 2009 January 30 to February 1 using NIRSPEC, the high-resolution (?/?? ? 25,000), long-slit echelle spectrograph at Keck 2. We sampled nine primary (parent) volatile species (H2O, C2H6, CH3OH, H2CO, CH4, HCN, C2H2, NH3, CO) and two product species (OH* and NH2). We also report upper limits for HDO and CH3D. C/2007 N3 (Lulin) displayed an unusual composition when compared to other comets. Based on comets measured to date, CH4 and C2H6 exhibited "normal" abundances relative to water, CO and HCN were only moderately depleted, C2H2 and H2CO were more severely depleted, and CH3OH was significantly enriched. Comet C/2007 N3 (Lulin) is another important and unusual addition to the growing population of comets with measured parent volatile compositions, illustrating that these studies have not yet reached the level where new observations simply add another sample to a population with well-established statistics.

Gibb, Erika L.; Bonev, Boncho P.; Villanueva, Geronimo; DiSanti, Michael A.; Mumma, Michael J.; Sudholt, Emily; Radeva, Yana

2012-05-01

425

Chemical composition and biological activities of the essential oil from Anredera cordifolia grown in Brazil.  

PubMed

The chemical composition of the essential oil of Anredera cordifolia (Ten.) Steenis (Basellaceae), grown in Brazil, was studied by means of GC and GC-MS analysis. In all, 19 compounds were identified, accounting for 91.6% of the total oil; hydrocarbons were the main constituents (67.7%). The essential oil was evaluated for its in vitro potential phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Sinapis arvensis L., and Phalaris canariensis L. seeds. At 1.25 microg/mL and 0.625 microg/mL, the oil significantly promoted the germination of S. arvensis. Moreover, the antimicrobial activity of the essential oil was assayed against ten bacterial strains. The essential oil showed a weak inhibitory activity against the Gram-positive pathogens. PMID:25230514

Souza, Lucéia Fátima; de Barros, Ingrid Bergman Inchausti; Mancini, Emilia; De Martino, Laura; Scandolera, Elia; De Feo, Vincenzo

2014-07-01

426