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1

Chemical Composition  

Microsoft Academic Search

Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and

Willie May; Richard Cavanagh; Gregory Turk; Michael Winchester; John Travis; Melody Smith; Paul Derose; Steven Choquette; Gary Kramer; John Sieber; Robert Greenberg; Richard Lindstrom; George Lamaze; Rolf Zeisler; Michele Schantz; Karen Phinney; Michael Welch; Thomas Vetter; Kenneth Pratt; John Scott; John Small; Scott Wight; Stephan Stranick

2006-01-01

2

Chemical Composition of Mish \\  

Microsoft Academic Search

This study was conducted to evaluate the chemical composition of mish during storage. Ninety samples of mish were collected on the day of manufacture (day one) from three different dairy plants (DP1, DP2, DP3), transported to the laboratory of the Department of Dairy Production, Faculty of Animal Production in ice box and stored at 7 C for 28 days. Samples

Mohamed Osman Mohamed Abdalla; Somaia Zonnoon; Abdel Nabi Ahmed

2010-01-01

3

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

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 grape canes  

Microsoft Academic Search

In this study, chemical composition of canes which were sampled from ten different grape cultivars was investigated. For the determination of total phenolics, total flavanols and total flavonol contents, canes were analyzed spectrophotometrically. The phenolic compositions of the canes, including caffeic acid, catechin, p-coumaric acid, epicatechin, gallic acid, luteolin and trans-resveratrol were detected by HPLC. The anthron method was used

Emine Sema Çetin; Duygu Altinöz; Ecehan Tarçan; Nilgün Göktürk Baydar

2011-01-01

6

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

7

Chemical degradation of composite restoratives.  

PubMed

The chemical environment is one aspect of the oral environment, which could have an appreciable influence on the in vivo degradation of composite restoratives. The effects of chemical media on surface hardness of four composite restoratives (Silux [SX], Z100 [ZO], Ariston [AR] and Surefil [SF]) were investigated. The relationship between hardness and the thickness of the degradation layer was also studied. Thirty six specimens (3 x 4 x 2 mm) were made for each material. Following polymerization, the specimens were stored in artificial saliva at 37 degrees C for 24 h. The specimens were then randomly divided into six groups of six, subjected to microhardness testing (load = 500 gf, dwell time = 15 s) and stored in the following chemicals for 1 week at 37 degrees C: artificial saliva (S), distilled water (W), 0.02 N citric acid (C), 0.02 N lactic acid (L), heptane (H) and 75-25% ethanol-water solution (E). After conditioning, the specimens were again subjected to hardness testing and sectioned. Change in hardness (DH) was computed and the thickness of the degradation layer (DL) was measured using a computerized image analysis system at 600x magnification. Results of statistical analysis (ANOVA/Scheffe's [P < 0.05]) of DH based on materials were as follows: SX - E > all other mediums; ZO - W > C; and AR - S, W, E > H (> indicates significantly greater hardness change). No significant difference in DH was observed between the different chemicals for SF. The effects of chemical media on DH were found to be material dependent. A significant but weak positive correlation (Pearson's correlation [P < 0.05]) exists between change in hardness and thickness of the degradation layer. PMID:11722717

Yap, A U; Tan, S H; Wee, S S; Lee, C W; Lim, E L; Zeng, K Y

2001-11-01

8

Chemical Composition of Martian Rocks  

NASA Astrophysics Data System (ADS)

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

Brueckner, J.

2007-05-01

9

Aerosol chemical composition over Istanbul.  

PubMed

This study examines the chemical composition of aerosols over the Greater Istanbul Area. To achieve this 325 (PM(10)) aerosol samples were collected over Bosphorus from November 2007 to June 2009 and were analysed for the main ions, trace metals, water-soluble organic carbon (WSOC), organic (OC) and elemental carbon (EC). PM(10) levels were found to be in good agreement with those measured by the Istanbul Municipality air quality network, indicating that the sampling site is representative of the Greater Istanbul Area. The main ions measured in the PM(10) samples were Na(+), Ca(2+) and non-sea-salt sulphates (nss-SO(4)(2-)). On average, 31% of Ca(2+) was found to be associated with carbonates. Trace elements related to human activities (as Pb, V, Cd and Ni) obtained peak values during winter due to domestic heating, whereas natural origin elements like Al, Fe and Mn peaked during the spring period due to dust transport from Northern Africa. Organic carbon was found to be mostly primary and elemental carbon was strongly linked to fuel oil combustion and traffic. Both OC and EC concentrations increased during winter due to domestic heating, while the higher WSOC to OC ratio during summer can be mostly attributed to the presence of secondary, oxidised and more soluble organics. Factor analysis identified six components/sources for aerosol species in PM(10), namely traffic/industrial, crustal, sea-salt, fuel-oil combustion, secondary and ammonium sulfate. PMID:20304466

Theodosi, C; Im, U; Bougiatioti, A; Zarmpas, P; Yenigun, O; Mihalopoulos, N

2010-03-21

10

Global Chemical Compositions Of Spiral Galaxies  

NASA Astrophysics Data System (ADS)

Understanding the chemical composition of a galaxy is vital to tracing its global evolution. However, characterizing overall abundances for spirals poses a challenge since these galaxies tend to possess gradients in their chemical compositions. Here, a recent proposal for determining global oxygen abundances for spirals is explored and extended. By separately integrating the absolute amounts of hydrogen and oxygen within circles of increasing radii, it is shown that the overall oxygen abundance generally approaches an asymptote. The asymptote is a viable measure of the overall chemical state of a spiral, and allows for comparisons of the chemical evolution with respect to other galaxies, such as dwarf irregulars, whose chemistry is better understood.

Dack, Stuart; McCall, M.

2011-05-01

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

The Chemical Composition of Maple Syrup  

ERIC Educational Resources Information Center

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

Ball, David W.

2007-01-01

13

Chemical Composition and Photometry of BE Lyncis  

Microsoft Academic Search

ABSTRACT.High-resolution spectroscopic observation was carried out to find the chemical composition of BE Lyn. The abundances of 25 chemical elements from carbon to neodymium were found. The deficiency of iron appeared to be equal to ?? log N(Fe) = -0.26 ± 0.08??logN(Fe)=-0.26±0.08 with respect to the solar metallicity, and the abundances of other elements were mainly undersolar. Only nitrogen, sodium,

Chulhee Kim; A. V. Yushchenko; S.-L. Kim; Y.-B. Jeon; Chun-Hwey Kim

2012-01-01

14

The Chemical Composition of iota Herculis, .  

National Technical Information Service (NTIS)

The chemical composition of the sharp-lined B3 V star iota Her has been determined by a model-atmosphere technique. All elements considered in this analysis seem to have solar-type abundances. The effective temperature determined for this star by the crit...

G. J. Peters L. H. Aller

1969-01-01

15

New Initiatives on RR Lyrae Chemical Compositions  

NASA Astrophysics Data System (ADS)

The serendipitous discovery by Preston and colleagues of the neutron-capture-enhanced RR Lyrae variable star TY Gru (a.k.a. CS 22881-071 in the ``HK'' survey of very metal-poor halo stars) has resulted in a growing set of initiatives on the chemical compositions of RR Lyrae stars and their application to broader topics in Galactic halo structure. Here we summarize the main aspects of our work on TY Gru, including a new discussion of our search for possible orbital motion of this star around a putative unseen companion. Then we describe a few of the results of a newly-completed intensive spectroscopic investigation of 10 additional field RR Lyr stars. We finish by outlining current projects that seek to contrast the atmospheres and chemical compositions of RRc stars with those of the RRab stars, and that employ a much larger RRab sample in a chemo-dynamical study of Galactic halo RR Lyr.

Sneden, Christopher; For, Bi-Qing; Preston, George W.

2011-08-01

16

Chemical Softening and Wear of Dental Composites  

Microsoft Academic Search

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

J. E. McKinney; W. Wu

1985-01-01

17

Chemical microsensors based on polymer fiber composites  

NASA Astrophysics Data System (ADS)

There is an urgent need for new chemical sensors for defense and security applications. In particular, sensors are required that can provide higher sensitivity and faster response in the field than existing baseline technologies. We have been developing a new solid-state chemical sensor technology based on microscale polymer composite fiber arrays. The fibers consist of an insulating polymer doped with conducting particles and are electrospun directly onto the surface of an interdigitated microelectrode. The concentration of the conducting particles within the fiber is controlled and is near the percolation threshold. Thus, the electrical resistance of the polymer fiber composite is very sensitive to volumetric changes produced in the polymer by vapor absorption. Preliminary results are presented on the fabrication and testing of the new microsensor. The objective is to take advantage of the very high surface to volume ratio, low thermal mass and linear geometry of the composite fibers to produce sensors exhibiting an extremely high vapor sensitivity and rapid response. The simplicity and low cost of a resistance-based chemical microsensor makes this sensing approach an attractive alternative to devices requiring RF electronics or time-of-flight analysis. Potential applications of this technology include battlespace awareness, homeland security, environmental surveillance, medical diagnostics and food process monitoring.

Kessick, Royal F.; Levit, Natalia; Tepper, Gary C.

2005-05-01

18

Titan's Interior Chemical Composition: A Thermochemical Assessment*  

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

19

Chemical composition of composted grape marc.  

PubMed

Composted grape marc, produced at the vineyard using different procedures, is generally returned into the vineyard. Information on the chemical composition of these grape marc composts is lacking, particularly the variability that may result from different composting practices. In this study, grape marc composts, varying in age from 3 months to 3 years, were collected from four different vineyards and subjected to detailed chemical analysis. The chemical analysis revealed that all the grape marc composts contained levels of free potassium, in the range of 2-3% w/w. Plant macronutrients such as Ca, S, Mg were present at low levels (<1% w/w), while phosphorus (0.1-0.3% w/w) and nitrogen (1-2% w/w) levels were not very high and mainly present in "plant unavailable" form. The levels of soluble salts, though not excessive, were elevated in all the composts. These salt levels could cause a problem in some soils. Heavy metals were not present in any significant levels. All the grape marc composts analysed provided some benefit in returning nutrients into the vineyard and all were significant potassium sources. PMID:19717914

Patti, Antonio F; Issa, G Jason; Smernik, Ron; Wilkinson, Kevin

2009-01-01

20

Chemical composition of selected edible nut seeds.  

PubMed

Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47-9.51%), protein (7.50-21.56%), lipid (42.88-66.71%), ash (1.16-3.28%), total soluble sugars (0.55-3.96%), tannins (0.01-0.88%), and phytate (0.15-0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16-44.54%) and acidic (27.95-33.17%) amino acids followed by basic (16.16-21.17%) and hydrophilic (8.48-11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (Aw range = 0.08-0.97) indicated a narrow range for monolayer water content (11-29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at Aw < 0.53 and 25 degrees C for 6 months. PMID:16787018

Venkatachalam, Mahesh; Sathe, Shridhar K

2006-06-28

21

Wood-plastic composites with reduced moisture : effects of chemical ...  

Treesearch

Title: Wood-plastic composites with reduced moisture : effects of chemical modification on ... Keywords: Ultraviolet radiation, weathering, polyethylene, wood flour, ... biodegradation, mechanical properties, wood-decaying fungi, deterioration, ...

22

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

23

Physical chemical properties of polyimide palladium nano - composite membranes  

Microsoft Academic Search

Polyimide polymer membranes posses' exceptional physical - chemical properties including excellent stability at relatively high temperatures (? 400°C), superior mechanical properties, and are highly resistant to various chemicals. Palladium is well known for its unique physical - chemical interactions with hydrogen. Interest in metal polymer composites can be attributed to the drive to produce a material with the savings in

Patrick Ndungu; Olushola Adeniyi; Leslie Petrik; Alexander Nechaev

2011-01-01

24

On-line chemical composition analyzer development  

SciTech Connect

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

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

1992-02-01

25

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

26

Chemical composition of French mimosa absolute oil.  

PubMed

Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound. PMID:20070087

Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

2010-02-10

27

Chemical composition of material fractions in Danish household waste  

Microsoft Academic Search

The chemical composition of Danish household waste was determined by two approaches: a direct method where the chemical composition (61 substances) of 48 material fractions was determined after hand sorting of about 20tonnes of waste collected from 2200 households; and an indirect method where batches of 80–1200tonnes of unsorted household waste was incinerated and the content of the waste determined

Christian Riber; Claus Petersen; Thomas H. Christensen

2009-01-01

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

Chemical composition of halo field stars and the chemical evolution of the halo  

Microsoft Academic Search

The chemical compositions of unevolved cool dwarfs of the halo and Population II and their implications for the chemical evolution of the Galactic halo are reviewed. The general metal-poorness of these stars is indicated, and the abundances of He; the light elements (H-2, H-3, Li, Be, and B); the C, N, O elements; Mg, Si, Ca and Ti; Na and

F. Spite

1983-01-01

30

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

31

On line chemical composition of analyzer development  

SciTech Connect

This status report details progress made on the development of an on-line chemical analyzer. Dynamic studies of the distillation column, approval of testing plans, installation of a sample cell and raman analyzer, design of computerized control systems are described. Information on seminars and published papers is also included. (GHH)

Not Available

1992-01-01

32

The Chemical Composition of the Hyades  

Microsoft Academic Search

The enrichment of various chemical elements with time in the Galaxy reveals the history of massive star formation and the production of supernovae. We have embarked on a study of elemental abundances in unevolved G stars in star clusters of a range in age to trace the evolution and mixing in the galactic disk. We have obtained Keck\\/HIRES spectra of

A. M. Boesgaard; J. L. Beard; J. R. King

2002-01-01

33

Analysis of the chemical composition of streamflow components  

Microsoft Academic Search

Although it is known that some water quality constituents are more closely related to storm flows than dry weather flow, there have been few attempts to explicitly study the chemical composition of individual components of flow. A computer program based upon quick flow and delayed flow separation has been adapted to estimate concentrations and total amounts of various chemical constituents

D. D. Huff; C. L. Begovich; G. S. Henderson

1978-01-01

34

Chemical composition of atmospheric aerosol in Dundee, UK  

Microsoft Academic Search

PM10 was sampled on weekdays and at weekends in Dundee, a coastal urban area in the UK, for 1 year. The chemical compositions of 59 PM10 samples were analysed by using wet chemical analysis methods. An atomic absorption spectrophotometer was used to analyse metal elements (Ca, Mg, Zn, Cu, Ni and Pb) while a high-performance liquid chromatography was used to

Y. Qin; K. Oduyemi

2003-01-01

35

Seasonal Changes in the Chemical Composition of Commingled Goat Milk  

Microsoft Academic Search

Production of goat milk cheese in North America has been growing rapidly during the past several years. However, information on chemical composition and its seasonal varia- tion of year-round bulk-collected goat milk is limited. The objective of this study was to analyze the chemical composi- tion of commercial goat milk shipments for an entire year to provide fundamental information for

Ming R. Guo; Peter H. Dixon; Young W. Park; James A. Gilmore; Paul S. Kindstedt

2001-01-01

36

Modeling chemical and physical body composition of the growing pig  

Microsoft Academic Search

In pig growth models, masses of body lipid (L) and body protein (P) are key state variables that can be related quantitatively to chemical and phys- ical body composition for predicting growth response and carcass characteristics. The main chemical constit- uents in the empty body weight (EBW) are water (Wa), L, P, and ash. Within pig genotypes, Wa is independent

C. F. M. de Lange; P. C. H. Morel; S. H. Birkett

2003-01-01

37

Chemical composition variations in shielded metal arc welds  

Microsoft Academic Search

The use of shielded metal arc (SMA) welding can result in chemical composition variations along the weld length. Manganese and silicon, commonly found in low-carbon steel welds, change in composition with weld position. This research was performed to better characterize the composition variations observed in structural steel welds and to understand the controlling factors that determine the extent of these

A. Q. Bracarense; S. Liu

1993-01-01

38

Composition Linear Control In Stirred Tank Chemical Reactors  

Microsoft Academic Search

This work studies loop control composition in continuous chemical reactors with simple structures, due to its large acceptance\\u000a in chemical industry. A linear cascade composition control (master\\/slave) is proposed, designed with basic control structures\\u000a based on Laplace tools. Two configurations are designed, which were evaluated in a dynamic model of continuous stirred tank. From a stability\\u000a analysis it is noted

A. Regalado Méndez; J. Álvarez Ramírez

39

Properties and Chemical Composition of Typical Coker Gas Oil  

Microsoft Academic Search

The coker gas oil from Daqing, Shengli, and Liaohe, which are three famous oil fields in China, are studied. The properties, chemical composition, and structural composition of coker gas oil from Daqing, Shengli, and Liaohe saturated hydrocarbon are analyzed. The results show that nitrogen and sulfur content in Daqing coker gas oil is the lowest, and saturated hydrocarbon content is

B. Hou; Z. Cao; W. Chen; J. Han

2007-01-01

40

The relationship of argon retentivity and chemical composition of hornblende  

SciTech Connect

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

Leake, B.E.; Farrow, C.M. (Univ. of Glasgow (Scotland)); Elias, E.M. (Univ. of Mosul (Iraq))

1988-08-01

41

"Chemical" composition of the Quark Gluon Plasma  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

42

Chemical composition of the galactic disk  

SciTech Connect

Metallicity indices delta/sub 0.6/, ..delta../sub R/-I(U-B), deltam/sub 1/(..beta..) are calculated for eight samples of main-sequence disk stars. The indices delta/sub 0.6/, ..delta..(U-B) are calibrated against the metallicity (Fe/H) for spectral types F, G, K separately; Sandage's method evidently does not fully take into account the effect of temperature on the ultraviolet excess. Together with the catalog of Morel et al., these data yield the distribution of stars with respect to metal abundance (the metallicity function). With high statistical confidence, stars having reliable metallicity determinations are subdivided by these distributions into two groups, separated by a dip in the metallicity function. The groups have mean metallicities (Fe/H)=-0.22 and +0.08, with a dispersion delta/sub / =0.10--0.11, and a normal random-error curve satisfactorily fits each group. Accordingly, the actual distribution of heavy elements among galactic-disk stars is essentially discrete. The kinematics and the color-magnitude diagram are considered for each metallicity group; the corresponding parameters differ, with the metal-poor stars being older. These results lend further support to the authors' previous findings that metal enrichment and star formation are discrete processes, associated with active phases in the evolution of the Galaxy. Evidence from U, B, V, and R, I photometry for F and K dwarfs indicates that the sun has the same metallicity as the Hyades, while the data for G dwarfs give the standard result that the sun is metal-deficient. The metal-abundance distributions as well show that the metal-rich group of F and K dwarfs have the same photometric metallicity as the Hyades, while the G dwarfs are poor in metals than the Hyades. The implications of the results for models of the chemical evolution of the Galaxy are discussed.

Marsakov, V.A.; Suchkov, A.A.

1980-01-01

43

Chemical Composition of the Essential Oils of Cupressus atlantica Gaussen  

Microsoft Academic Search

The chemical composition of essential oils obtained by hydrodistillation of the wood, leaves and cones of Cupressus atlantica Gaussen (Cupressaceae) was studied by GC and GC\\/MS. Oxygenated sesquiterpenes constituted the main chemical groups in the oil from wood, with cedrol (45.1%) as the major component. The oil from leaves contained higher amounts of sesquiterpenes with germacrene D (13.1%) and ?-muurolol

A. F. Barrero; M. M. Herrador; P. Arteaga; J. Quílez; M. Piedra; M. Akssira; M. Aitigri; A. Bennamara

2005-01-01

44

Chemical vapor composite silicon carbide for space telescopes  

Microsoft Academic Search

Components for space telescopes using high quality silicon carbide (SiC) produced via the chemical vapor composite (CVC) process are currently under development. This CVC process is a modification of chemical vapor deposition (CVD) and results in a dramatic reduction in residual stress of the SiC deposit. The resultant CVC SiC material has high modulus, high thermal conductivity and can be

C. T. Tanaka; K. Webb

2006-01-01

45

Chemical Composition of Wild2 Dust Collected by Stardust  

Microsoft Academic Search

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

G. J. Flynn

2006-01-01

46

The Relations of Chemical Composition and Physical Behavior of Some Asphalts Used in Pennsylvania.  

National Technical Information Service (NTIS)

The paper attempts to correlate chemical composition of asphalts with their physical behavior and to illustrate that changes in chemical composition parallel changes in physical behavior. The chemical analysis used was a modification of the precipitation ...

W. H. Gotolski J. M. Lucas S. K. Ciesielski

1966-01-01

47

Chemical composition of Cynara scolymus leaves  

Microsoft Academic Search

methionine. The amino-acid composition was studied in further detail as before [3]. The qualitative composition of amino acids was determined from retention times. The internal standard was a standard mixture of 18 amino acids. Colored complexes that were formed by reaction with ninhydrin were measured colorimetrically at 570 nm. Peak areas of identified acids were used for quantitative determination (automatically).

T. V. Orlovskaya; I. L. Luneva; V. A. Chelombit’ko

2007-01-01

48

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

49

Chemical constraints on fly ash glass compositions  

SciTech Connect

The major oxide content and mineralogy of 75 European fly ashes were examined, and the major element composition of the glass phase was obtained for each. Correlation of compositional trends with the glass content of the ash was explored. Alkali content was deduced to have a major influence on glass formation, and this in turn could be related to the probable chemistry of clay minerals in the source coals. Maximal glass content corresponded to high aluminum content in the glass, and this is in accordance with the theoretical mechanism of formation of aluminosilicate glasses, in which network-modifying oxides are required to promote tetrahedral coordination of aluminum in glass chain structures. Iron oxide was found to substitute for alkali oxides where the latter were deficient, and some indications of preferred eutectic compositions were found. The work suggests that the proportion of the glass phase in the ash can be predicted from the coal mineralogy and that the utility of a given ash for processing into geopolymers or zeolites is determined by its source. 23 refs., 7 figs., 1 tab.

John H. Brindle; Michael J. McCarthy [University of Dundee, Dundee (United Kingdom). Division of Civil Engineering

2006-12-15

50

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

51

Chemical Composition of Chlamydospores of Candida albicans  

PubMed Central

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

Jansons, Vilma K.; Nickerson, Walter J.

1970-01-01

52

Chemical Composition of Icy Satellite Surfaces  

NASA Astrophysics Data System (ADS)

Much of our knowledge of planetary surface composition is derived from remote sensing over the ultraviolet through infrared wavelength ranges. Telescopic observations and, in the past few decades, spacecraft mission observations have led to the discovery of many surface materials, from rock-forming minerals to water ice to exotic volatiles and organic compounds. Identifying surface materials and mapping their distributions allows us to constrain interior processes such as cryovolcanism and aqueous geochemistry. The recent progress in understanding of icy satellite surface composition has been aided by the evolving capabilities of spacecraft missions, advances in detector technology, and laboratory studies of candidate surface compounds. Pioneers 10 and 11, Voyagers I and II, Galileo, Cassini and the New Horizons mission have all made significant contributions. Dalton (Space Sci. Rev., 2010, this issue) summarizes the major constituents found or inferred to exist on the surfaces of the icy satellites (cf. Table 1 from Dalton, Space Sci. Rev., 2010, this issue), and the spectral coverage and resolution of many of the spacecraft instruments that have revolutionized our understanding (cf. Table 2 from Dalton, Space Sci. Rev., 2010, this issue). While much has been gained from these missions, telescopic observations also continue to provide important constraints on surface compositions, especially for those bodies that have not yet been visited by spacecraft, such as Kuiper Belt Objects (KBOs), trans-Neptunian Objects (TNOs), Centaurs, the classical planet Pluto and its moon, Charon. In this chapter, we will discuss the major satellites of the outer solar system, the materials believed to make up their surfaces, and the history of some of these discoveries. Formation scenarios and subsequent evolution will be described, with particular attention to the processes that drive surface chemistry and exchange with interiors. Major similarities and differences between the satellites are discussed, with an eye toward elucidating processes operating throughout the outer solar system. Finally we discuss the outermost satellites and other bodies, and summarize knowledge of their composition. Much of this review is likely to change in the near future with ongoing and planned outer planet missions, adding to the sense of excitement and discovery associated with our exploration of our planetary neighborhood.

Dalton, J. B.; Cruikshank, D. P.; Stephan, K.; McCord, T. B.; Coustenis, A.; Carlson, R. W.; Coradini, A.

2010-06-01

53

Chemical imaging of wood-polypropylene composites.  

PubMed

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

Harper, David P; Wolcott, Michael P

2006-08-01

54

Chemical Composition and Mineralogy of Marine Sediments  

NASA Astrophysics Data System (ADS)

The earliest reports on the composition of deep-sea sediments resulted from the Challenger Expedition (1873-1876) (e.g., Tizzard et al., 1885; Murray and Renard, 1891). Many review papers on marine sediment composition have subsequently been published, including the ones by Revelle (1944), El Wakeel and Riley (1961), Arrhenius (1963), Goldberg (1963), Chester and Aston (1976), Glasby (1977), Bischoff and Piper (1979), Baturin (1982, 1988), Notholt and Jarvis (1990), Nicholson et al. (1997), Glenn et al. (2000), and Li (2000). The constituents of a marine sediment are often classified according to their origin ( Table 1; after Goldberg, 1963). The detrital component is made up of cosmogenous and lithogenous materials. Cosmic spherules contain particles of FeNi that are formed by ablation of iron meteorites as they pass through Earth's atmosphere, as well as fragments of silicate chondrules ( Arrhenius, 1963). Lithogenous constituents of marine sediments are the minerals derived from weathering of rock on land or on the seafloor, or from the volcanic eruptions ( Goldberg, 1963; see review in Windom (1976)). The biogenous component is made up of the tests of planktic and benthic organisms, as well as biogenic apatite (see review in Berger (1976)). The hydrogenous fraction of marine sediment encompasses phases formed by inorganic precipitation from seawater. Elderfield (1976) and Piper and Heath (1989) provide comprehensive reviews of hydrogenous material in marine sediments.

Li, Y.-H.; Schoonmaker, J. E.

2003-12-01

55

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

56

The influence of inclusion chemical composition on weld metal microstructure  

Microsoft Academic Search

The effects of nonmetallic inclusions on weld metal microstructures were investigated. The inclusions were extracted from\\u000a niobium microalloyed steel weld metal specimens, and examined with light and electron microscopic techniques. An EDS (Energy\\u000a Dispensive Spectroscopy) system was used to determine the chemical composition of the inclusions. Correlation between weld\\u000a metal and inclusion composition was established. Aluminum, titanium, sulfur, and iron

S. Liu; D. L. Olson

1987-01-01

57

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

58

Chemical composition of Cystoseira crinita Bory from the Eastern Mediterranean.  

PubMed

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

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

59

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

60

The chemical and physical composition of water trees in XLPE  

Microsoft Academic Search

The arguments supporting a model of the composition of water trees are updated with additional information concerning inorganic salts in water trees. It is pointed out that water trees are in fact salt trees. Hydrophilic tracks (rather than channels) run through the amorphous phase of polyethylene. The hydrophilic groups are carboxylate salts chemically bonded to the polymer matrix and trapped

R. Ross; J. J. Smit

1991-01-01

61

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

62

Influence of the chemical composition on the machinability of brasses  

Microsoft Academic Search

Although brasses are essentially copper and zinc alloys, they also contain other alloying elements such as lead, silicon, aluminium, iron, tin, manganese, nickel or arsenic whose presence and content are responsible for the wide variety of properties inherent to these materials.In this article, the effect of the chemical composition of brasses, considering each alloying element and the effective copper content,

C. Vilarinho; J. P. Davim; D. Soares; F. Castro; J. Barbosa

2005-01-01

63

Chemical composition of throughfall and stemflow from citrus canopies  

Microsoft Academic Search

The main objective of this study was to examine the chemical composition of incident rainfall, throughfall, and stemflow from canopies of ‘Marsh’ grapefruit, and ‘Hamlin’ and ‘Temple’ orange trees. The concentrations of ammonium (NH4) and nitrate (NO3) were lower in the throughfall under the canopy or along the dripline as compared to those in the incident rainfall. This reduction is

Y. C. Li; A. K. Alva; D. V. Calvert; M. Zhang

1997-01-01

64

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

Microsoft Academic Search

The antimicrobial activity of the Centipeda minima L. (Asteraceae) extract was evaluated against seven microorganisms using the disc diffusion method. The extract showed a broad spectrum of antimicrobial activity against all the tested bacterial strains, especially Enterobacter aerogenes, Klebsiella pneumonia, Staphylococcus aureus and Yersinia enterocolitica. The chemical composition of the extract obtained fromCentipedaminima was analysed by GC-MS. Twenty - three

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

65

Categorizing rice cultivars based on differences in chemical composition  

Microsoft Academic Search

This research aimed to verify variations in chemical composition of rice cultivars after polishing and to evaluate the constancy between two cultivated years in order to categorize them into groups with distinct nutritional characteristics. The cultivation year only significantly affected the Ash values. Categorizing cultivars showed that some of them presented a standard pattern for some measures. The groups formed

Cátia Regina Storck; Leila Picolli da Silva; Carlos Alberto Alves Fagundes

2005-01-01

66

Multi-energy techniques for radiographic monitoring of chemical composition  

NASA Astrophysics Data System (ADS)

A theoretical model of multi-energy radiography (MER) is proposed. It is shown that, as distinct from the conventional radiography, MER allows identification of organic substances and control of their chemical composition. Broad prospects are noted for MER application, specifically, for detection of prohibited substances (explosives, drugs, etc.) during customs and anti-terrorist safety inspection.

Naydenov, S. V.; Ryzhikov, V. D.

2003-06-01

67

Fuel options from microalgae with representative chemical compositions  

Microsoft Academic Search

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

1984-01-01

68

Anisotropy vs chemical composition at ultra-high energies  

Microsoft Academic Search

This paper proposes and discusses a test of the chemical composition of ultra-high energy cosmic rays that relies on the anisotropy patterns measured as a function of energy. In particular, we show that if one records an anisotropy signal produced by heavy nuclei of charge Z above an energy Ethr, one should record an even stronger (possibly much stronger) anisotropy

Martin Lemoine; Eli Waxman

2009-01-01

69

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

Microsoft Academic Search

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

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

2000-01-01

70

[Chemical composition of Creole cattle meat].  

PubMed

Proximal composition was determined in meat's Creole cattle (CGBC). For this purpose, four raw cuts of CGBC were analyzed: buttock, flank, loin blade steak, and shoulder blade steak. The mentioned names of the meat cuts come from the National Meat Bureau from the Republic of Argentina. These cuts were taken from an experimental lot of Creole cattle (n = 11) in Jujuy province. Comparisons were made with data extracted from Argentine Table of Food Composition, edited by National Nutrition Institute, Buenos Aires, Argentina (1942). The results show that the level of protein is slightly inferior (in the case of CGBC varies between 18.44 +/- 0.30 and 21.06 +/- 0.11 g/100 g, while in the CTE varies between 20 and 23.8 g/100 g). The content of lipids in the cuts without visible fat is variable (1.06 +/- 0.01 to 2.74 +/- 0.61 g/100 g in the cuts of CGBC and 1.4 to 8.4 for the cuts of CTE). The content of minerals is similar (Fe 2.26 +/- 0.18 to 2.35 +/- 0.23 mg/100 g in CGBC, while in the CTE varies between 3.15 and 3.46 mg/100 g; Phosphorous varies between 142 +/- 10 and 170 +/- 11 mg/100 g in CGBC and 186 to 213 mg/100 g in CTE). These outcomes allow to affirm that the quality of CGBC beef is very similar to CTE beef with regard to principal nutrients. PMID:11464673

Farfán, N; Juarez, D; Rossi, A; Sammán, N

2000-12-01

71

The Chemical Composition of Mercury's Exosphere  

NASA Astrophysics Data System (ADS)

Mercury does not have a dense atmosphere whose altitude dependence is described by a single scale height. The Ultraviolet Spectrometer (UVS) instrument on Mariner 10 discovered a tenuous exosphere with gaseous species H, He, and O. Since the Mariner 10 flybys, ground-based telescopes have been used to observe the exosphere of Mercury in the Na and K spectroscopic D lines. Calcium has been observed primarily in the polar and anti-sunward exosphere. Radar-bright regions have been discovered at the poles, attributed to volatile deposits (water or sulfur) in permanently shadowed craters. Recently, Mg was discovered during MESSENGER's second flyby of Mercury. Many more species are predicted to exist in Mercury's exosphere, and they are a diagnostic of the surface composition. In many cases, orders-of magnitude differences exist in the predictions of abundances from different models because of our current lack of understanding of Mercury's surface composition and source processes. The small amount of O at the base of the exosphere (n[O] < 4 × 104 particles/cm-3) relative to the surface abundance (~50%) is surprising. This may indicate that the exospheric O is bound in molecules, is inefficiently desorbed, or efficiently escapes. Elements such as Na, Ca, Ar, Ne and S are expected to yield critical information about Mercury's surface. To fully characterize the temporal and spatial variability of Mercury's exosphere, correlated in situ and ground-based observations are essential. Measurements of Na will enable these correlations. Calcium is a refractory element and may be considered a tracer of ion sputtering processes. Both 36Ar and Ne are not expected to be endogenic to Mercury, but implanted by the solar wind. The S content in Mercury's crust and interior is highly diagnostic of the planet's origin.

Ho, George; Livi, Stefano; Kasper, Justin; Desai, Mihir; Wurz, Peter; Orsini, Stefano; Milillo, Anna

2010-05-01

72

Fast, Contactless Monitoring of the Chemical Composition of Raw Materials  

NASA Astrophysics Data System (ADS)

A technique to monitor chemical composition of materials during manufacturing of ceramic products, in particular - of bricks, is investigated. The technique of monitoring is likely to offset environmental pollution and save energy. For this purpose, we use the Surface photo charge effect, which is generated for each solid body interacting with electromagnetic field. The measurement is express and can be performed in-situ in production conditions. The experimental work has shown that different samples of the investigated materials with different compositions produce different signals specific to each sample. For the same material, the signal varies with the change in chemical composition. More specifically, it is shown that for the material from which the bricks are fired, the signal is a function of the percentage of coal sludge. The results indicate that the characterization technique as a viable technique for control of incoming raw materials.

Ivanov, O.; Stoyanov, Zh.; Stoyanov, B.; Nadoliisky, M.; Vaseashta, Ashok

73

Chemical Composition of Globulars of the Sagittarius System  

NASA Astrophysics Data System (ADS)

We will present results about the abundances of iron, alpha-elements, and the r-process element Eu of six red giant stars belonging to Sagittarius globular clusters Terzan 8 and Arp 2. The Sagittarius dwarf galaxy (Sgr) offers an opportunity to study the chemical evolution of a galaxy very different from the Milky Way. Detailed chemical composition measurements of the Sgr globular clusters (GCs) will permit us to define the differences between this dwarf galaxy and the Milky Way, that would provide a check on current ideas in the chemical evolution, place constraints on the star formation rate and IMF in the Sgr, and set limits on the accretion of objects similar to Sgr in the construction of the Galactic halo. Thus, it is particularly important to have a complete census of the handful of GCs (M54, Terzan 7, Pal 12, Terzan 8, and Arp 2) associated with the Sgr galaxy. Well determined chemical composition for the most metal-poor Sgr GCs would be very useful, as currently there is data only for M54. Photometric estimates suggest that Ter 8 and Arp 2 have metallicities near -1.6 and -2.0 dex respectively. Thus, these two GCs are vital to our knowledge of the metal-poor Sgr GC population and they are also thought to be among the oldest GCs in the Sgr system, so their measured abundances would significantly clarify the age-composition relation of the Sgr dwarf galaxy. With the scenario described above in mind, we have collected high-resolution spectra of six red giant stars to undertake the first detailed chemical abundance analysis of globular clusters Terzan 8 and Arp 2. Spectra with resolving power of 40,000 and spectral range between 3400 and 9400 A were obtained with the echelle spectrograph MIKE mounted on the 6.5m telescope at Las Campanas Observatory.

Mottini, Marta; Wallerstein, G.; McWilliam, A.

2006-12-01

74

Leaching Properties and Chemical Compositions of Calcines Produced at the Idaho Chemical Processing Plant.  

National Technical Information Service (NTIS)

No significant chemical differences were determined between retrieved and fresh calcine based on chemical and spectrochemical analyses. Little can be derived from the amounts of the radioisotopes present in the retrieved calcine samples other than the rat...

B. A. Staples B. E. Paige D. W. Rhodes M. W. Wilding

1980-01-01

75

Chemical composition and antibacterial activity of Gongronema latifolium  

Microsoft Academic Search

Chemical composition of Gongronema latifolium leaves was determined using standard methods. Aqueous and methanol G. latifolium extracts were tested against thirteen pathogenic bacterial isolates. Crude protein, lipid extract, ash, crude fibre and nitrogen\\u000a free extractives obtained are: 27.2%, 6.07%, 11.6%, 10.8% and 44.3% dry matter respectively. Potassium, sodium, calcium, phosphorus\\u000a and cobalt contents are 332, 110, 115, 125 and 116

Afolabi F. Eleyinmi

2007-01-01

76

Chemical composition and immunological properties of glycoproteins of Sporothrix species  

Microsoft Academic Search

Glycoproteins of 11Sporothrix species were purified from their respective culture filtrates by use of DEAE-Sephadex A-50 and QAE-Sephadex A-25 column chromatography\\u000a and investigated for their chemical and immunological properties. On the basis of sugar composition, the glycoproteins of\\u000a the 11Sporothrix species could be divided into two groups, i.e., rhamnose containing (i.e., Rha+), and non rhamnose containing (i.e., Rha?) groups. The

Y. Kurata

1981-01-01

77

Tropospheric chemical composition - Overview of experimental methods in measurement  

NASA Astrophysics Data System (ADS)

Methods used to measure various aspects of tropospheric chemical composition are discussed. Particular attention is given to the determination of trace species at levels which can be below 1 part in 10 to the 12th in the gas, aqueous, and aerosol phases. It is shown that the precision of a measurement tends to be an inverse function of the atmospheric mixing ratio and species reactivity.

Ayers, G. P.; Gillett, R. W.

1990-08-01

78

Chemical composition and biological activities of Arachis species.  

PubMed

Arachis hypogaea , known as the peanut, is native to South America. Peanut contains several active components including flavonoids, phenolic acids, phytosterols, alkaloids, and stilbenes. Some therapeutic effects have been reported for peanut seed extracts, such as antioxidative, antibacterial, antifungal, and anti-inflammatory activities. This paper aims to give an overview of the chemical composition, focusing on secondary metabolites, and of the biological activity of A. hypogaea, to stimulate new studies about species of the Arachis genus. PMID:21425852

Lopes, Renata Miranda; Agostini-Costa, Tânia da Silveira; Gimenes, Marcos Aparecido; Silveira, Dâmaris

2011-04-14

79

Effect of chemical compositions on temperature susceptibility of bitumens  

Microsoft Academic Search

The viscosity of five bitumens was measured at different temperatures and the viscosity- temperature relationship was developed\\u000a to evaluate the temperature susceptibility of different bitumens. The generic fractions (i e, saturates, aromatics, resins and asphaltenes) of the bitumens were separated and tested by thin-layer chromatography with\\u000a flame ionization detection (TLC-FID) and the effect of chemical compositions on temperature susceptibility of

Yongsheng Liang; Zhengang Feng; Jianying Yu

2010-01-01

80

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

81

The chemical composition of the halo and evolutionary problems  

Microsoft Academic Search

The chemical composition of the Milky-Way halo is studied on the basis of a sample of metal-poor (logarithmic metallicity\\u000a less than –1) globular clusters. The histogram obtained may be interpreted in the terms of the classical galaxy formation\\u000a theory of Eggen, Lynden-Bell and Sandage. Interestingly enough, this is in a rough agreement with the data on metallicity\\u000a of high-redshift damped

S. Ninkovic; M. ?irkovi?

2003-01-01

82

Chemical composition and in vitro antibacterial activity of Seseli libanotis  

Microsoft Academic Search

Summary  The antibacterial efficacy of the methanol extract of the aerial parts of Seseli libanotis by using disc diffusion assay against 107 strains from 52 bacterial species and the chemical composition of the essential\\u000a oil using GC\\/MS analysis were studied for the first time. The minimum inhibitory concentrations (MIC) of single compounds\\u000a were determined by the microbroth dilution method. Gas chromatography–mass

Suzan Ozturk; Sezai Ercisli

2006-01-01

83

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

84

Chemical composition of an unusual xenolith of the Allende meteorite.  

NASA Astrophysics Data System (ADS)

The chemical composition of an unusual xenolith (All-AF) from the Allende meteorite was determined by neutron activation and X-ray fluorescence analyses. The xenolith is similar in bulk composition to Allende, but has large excesses in some moderately volatile trace elements, such as Na, K, Au, Sb etc. Some of these elements show considerable variations in other components of Allende, suggesting inhomogeneous distribution in Allende. However, elements of higher volatility, such as Zn and Se have concentrations typical of bulk Allende and other type 3 carbonaceous chondrites. Therefore, All-AF must have formed from the same reservoir as bulk Allende.

Palme, H.; Kurat, G.; Spettel, B.; Burghele, A.

1989-10-01

85

Changes in Body Chemical Composition of Rats after Spaceflight as Determined with Negatively Charged Muons.  

National Technical Information Service (NTIS)

The body chemical composition of three white rats of the ''Wistar'' line was investigated by the muonic x-ray spectroscopy technique, following three weeks in spaceflight on earth satellites ''Cosmos-605'' and ''Cosmos-690''. The chemical composition of t...

R. D. Arlt V. S. Evseev H. G. Ortlepp B. M. Sabirov H. Haupt

1978-01-01

86

The chemical composition of ionized gas in galaxies  

NASA Astrophysics Data System (ADS)

Active star formation in galaxies takes place in HII regions harbouring young massive stars within an extended ionized gaseous component. Their relative structural simplicity andcharacteristic emission line spectrum make them ideal laboratories to study the physical properties and chemical composition of gas and stars in galaxies. Chemical abundancescan be derived for Galactic and relatively nearby extragalactic HII regions, as well as for distant galaxies, applying different techniques. In this talk an overview of the derivation of chemical abundances for HII regions in galaxies is presented, with an emphasis on the different domains of spatial resolution covered by the data, from spatially resolved integral field spectra of HII regions in the Milky Way and nearby galaxies to integrated spectra of more distant galaxies.With the upcome of the new integral field spectrographs a wide coverage at good spatial sampling of galaxies and HII complexes is now possible. This new 2D spectroscopy provides us more realistic information and useful constrains to study the chemical enrichment process of the interstellar medium and some of the fundamental relations governing galaxy evolution.

Vilchez, J. M.

2011-11-01

87

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

88

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

89

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

90

On the chemical composition of Titan's dry lakebed evaporites  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

91

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

92

Dynamics of the chemical composition of rainwater throughout Hurricane Irene  

NASA Astrophysics Data System (ADS)

Sequential sampling of rainwater from Hurricane Irene was carried out in Wilmington, NC, USA on 26 and 27 August 2011. Eleven samples were analyzed for pH, major ions (Cl-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+, NH4+), dissolved organic carbon (DOC) and hydrogen peroxide (H2O2). Hurricane Irene contributed 16% of the total rainwater and 18% of the total chloride wet deposition received in Wilmington NC during all of 2011. This work highlights the main physical factors influencing the chemical composition of tropical storm rainwater: wind speed, wind direction, air mass back trajectory and vertical mixing, time of day and total rain volume. Samples collected early in the storm, when winds blew out of the east, contained dissolved components indicative of marine sources (salts from sea spray and low DOC). The seasalt components in the samples had two maxima in concentration during the storm the first of which occurred before the volume of rain had sufficiently washed out seasalt from the atmosphere and the second when the air mass dipped to low elevations over the Atlantic Ocean followed by rapid vertical mixing. As the storm progressed and winds shifted to a westerly direction, the chemical composition of the rainwater became characteristic of terrestrial storms (high DOC and NH4+ and low seasalt). This work demonstrates that tropical storms are not only responsible for significant wet deposition of marine components to land, but terrestrial components can also become entrained in rainwater, which can then be delivered to coastal waters via wet deposition. This study also underscores why analysis of one composite sample can lead to an incomplete interpretation of the factors that influence the chemically divergent analytes in rainwater during extreme weather events.

Mullaugh, K. M.; Willey, J. D.; Kieber, R. J.; Mead, R. N.; Avery, G. B., Jr.

2012-10-01

93

Dynamics of the chemical composition of rainwater throughout Hurricane Irene  

NASA Astrophysics Data System (ADS)

Sequential sampling of rainwater from Hurricane Irene was carried out in Wilmington, NC, USA on 26 and 27 August 2011. Eleven samples were analyzed for pH, major ions (Cl-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+, NH4+), dissolved organic carbon (DOC) and hydrogen peroxide (H2O2). Hurricane Irene contributed 16% of the total rainwater and 18% of the total chloride wet deposition received in Wilmington NC during all of 2011. This work highlights the main physical factors influencing the chemical composition of tropical storm rainwater: wind speed, wind direction, back trajectory and vertical mixing, time of day and total rain volume. Samples collected early in the storm, when winds blew out of the east, contained dissolved components indicative of marine sources (salts from sea spray and low DOC). The sea-salt components in the samples had two maxima in concentration during the storm the first of which occurred before the volume of rain had sufficiently washed out sea salt from the atmosphere and the second when back trajectories showed large volumes of marine surface air were lifted. As the storm progressed and winds shifted to a westerly direction, the chemical composition of the rainwater became characteristic of terrestrial storms (high DOC and NH4+ and low sea salt). This work demonstrates that tropical storms are not only responsible for significant wet deposition of marine components to land, but terrestrial components can also become entrained in rainwater, which can then be delivered to coastal waters via wet deposition. This study also underscores why analysis of one composite sample can lead to an incomplete interpretation of the factors that influence the chemically divergent analytes in rainwater during extreme weather events.

Mullaugh, K. M.; Willey, J. D.; Kieber, R. J.; Mead, R. N.; Avery, G. B., Jr.

2013-03-01

94

[Changes in chemical composition of tomatoes during processing].  

PubMed

The influences of processing conditions and composition on chemical changes during thermal processing of tomatoes were investigated. During the Cold and Hot Break process pectin is degraded to different extents. Due to the thermal impact at first cyclization of glutamine to pyroglutamic acid takes place. At higher dry weight contents and during drying processes Amadori compounds and browning can be detected. The reaction products formed during thermal processing can be analysed by amino acid analysis and-after proper derivatization-by capillary gas chromatography. PMID:8711954

Schräder, I; Eichner, K

1996-06-01

95

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

96

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

97

Supercapacitance of chemically converted graphene with composite pores  

NASA Astrophysics Data System (ADS)

We report the synthesis and characterization of chemically converted graphene (CCG) with composite pores that has exhibited high specific capacitance (up to 350 F g?1). The porous CCG was obtained by photocatalytic reaction aided by ZnO quantum dots and it has both macropores (>50 nm) and meso/micro-pores (<10 nm). The introduction of macropores allowed penetration of electrolyte into the inter-layer space of CCG while the meso/micro-pores increased the adsorption of charges. The supercapacitor made from such porous CCG also exhibited excellent rate performance and cyclic stability.

Zhou, Ming; Tian, Tian; Li, Xuanfu; Sun, Xudong; Zhang, Juan; Chen, Youhu; Cui, Ping; Tang, Jie; Qin, Lu-Chang

2013-08-01

98

Chemical composition of essential oil from Calligonum polygonoides Linn.  

PubMed

The essential oil from air dried buds and roots of Calligonum polygonoides Linn., has been extracted from dry steam distillation and analysed for chemical composition by gas chromatography-mass spectrometry. In total, 27 and 10 compounds were analysed qualitatively and quantitatively, accounting for 68.42% and 82.12% total contents of the essential oils of buds and roots, respectively. It contains a complex mixture of terpenoids, hydrocarbons, phenolic compounds, acid derivatives and ketones. The main component of essential oil was ethyl homovanillate (11.79%) in buds and drimenol (29.42%) in roots. PMID:22574752

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

2012-05-11

99

IR spectroscopic study of the chemical composition of epiphytic lichens  

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

100

Design of an artificial skin. II. Control of chemical composition.  

PubMed

Detailed methodology is described for the reproducible preparation of collagen--glycosaminoglycan (GAG) membranes with known chemical composition. These membranes have been used to cover satisfactorily large experimental full-thickness skin wounds in guinea pigs over the past few years. Such membranes have effectively protected these wounds from infection and fluid loss for over 25 days without rejection and without requiring change or other invasive manipulation. When appropriately designed for the purpose, the membranes have also strongly retarded wound contraction and have become replaced by newly synthesized, stable connective tissue. In our work, purified, fully native collagen from two mammalian sources is precipitated from acid dispersion by addition of chondroitin 6-sulfate. The relative amount of GAG in the coprecipitate varies with the amount of GAG added and with the pH. Since coprecipitated GAG is generally eluted from collagen fibers by physiological fluids, control of the chemical composition of membranes is arrived at by crosslinking the collagen--GAG ionic complex with glutaraldehyde, or, alternately, by use of high-temperature vacuum dehydration. Appropriate use of the crosslinking treatment allows separate study of changes in membrane composition due to elution of GAG by extracellular fluid in animal studies from changes in composition due to enzymatic degradation of the grafted or implanted membrane in these studies. Exhaustive in vitro elution studies extending up to 20 days showed that these crosslinking treatments insolubilize in an apparently permanent manner a fraction of the ionically complexed GAG, although it could not be directly confirmed that glutaraldehyde treatment covalently crosslinks GAG to collagen. By contrast, the available evidence suggests strongly that high-temperature vacuum dehydration leads to formation of chemical bonds between collagen and GAG. Procedures are described for control of insolubilized and "free" GAG in these membranes as well as for control of the molecular weight between crosslinks (Mc). The insolubilized GAG can be controlled in the range 0.5--10 wt. % while "free" GAG can be independently controlled up to at least 25 wt. %; Mc can be controlled in the range 2500--40,000. Studies by infrared spectroscopy have shown that treatment of collagen--GAG membranes by glutaraldehyde or under high-temperature vacuum does not alter the configuration of the collagen triple helix in the membranes. Neither do these treatments modify the native banding pattern of collagen as viewed by electron microscopy. Collagen--GAG membranes appear to be useful as chemically well-characterized, solid macromolecular probes of biomaterial--tissue interactions. PMID:7358747

Yannas, I V; Burke, J F; Gordon, P L; Huang, C; Rubenstein, R H

1980-03-01

101

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

NASA Astrophysics Data System (ADS)

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

Hawthorne, Frank C.

2012-11-01

102

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

Microsoft Academic Search

We describe an SPH model for chemical enrichment and radiative cooling in cosmo- logical 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;

F. J. Mart; A. Serna; R. Dom ´ õnguez-Tenreiro; M. Molla

103

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

Microsoft Academic Search

We describe an smooth particle hydrodynamics (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

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

2008-01-01

104

Chemical Compositions of Stars in Globular Cluster NGC 2419  

NASA Astrophysics Data System (ADS)

We determine the chemical abundances of 19 red giant branch stars in the Galactic globular cluster NGC 2419. Lying at a distance of 84.2 kpc and a galactocentric distance of 91.5 kpc, NGC 2419 is the fourth brightest globular cluster in the Milky Way with a total magnitude of M_V = -9.6 mag, which is significantly brighter than M_V = -7.5 mag, the typical peak of the globular cluster luminosity functions in external galaxies. Our results will give an insight of whether NGC 2419 is in fact a globular cluster or a core of a disrupted galaxy that merged with the Milky Way. We have used IRAF to reduce spectra we have taken with the DEIMOS spectrograph on the the Keck I 10-meter telescope. Using the strengths of the Ca II triplet absorption lines at approximately 8600 Angstrom, we will determine the chemical abundance of each star. If the chemical abundances differ by significantly more than the observational errors would predict then we can conclude the cluster is a remnant of the core of a galaxy that merged with the Milky Way and not a normal globular cluster, because most globular clusters formed quickly from a well mixed gas cloud, and thus their stars have nearly identical ages and chemical compositions. We gratefully acknowledge financial support from a UROP grant to SK and NSF grant AST-0307863 to TSH. These data were obtained at the Keck Observatory, operated by the California Inst. of Technology, Univ. of California and NASA and made possible by generous financial support from the W.M. Keck Foundation.

Kadakia, Shimonee; Smecker-Hane, T.; Bosler, T.

2007-05-01

105

Reinforced polypropylene composites: effects of chemical compositions and particle size.  

PubMed

In this work, the effects of wood species, particle sizes and hot-water treatment on some physical and mechanical properties of wood-plastic composites were studied. Composites of thermoplastic reinforced with oak (Quercus castaneifolia) and pine (Pinus eldarica) wood were prepared. Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were used as the polymer matrix and coupling agent, respectively. The results showed that pine fiber had significant effect on the mechanical properties considered in this study. This effect is explained by the higher fiber length and aspect ratio of pine compared to the oak fiber. The hot-water treated (extractive-free) samples, in both wood species, improved the tensile, flexural and impact properties, but increased the water absorption for 24h. This work clearly showed that lignocellulosic materials in both forms of fiber and flour could be effectively used as reinforcing elements in PP matrix. Furthermore, extractives have marked effects on the mechanical and physical properties. PMID:19948401

Ashori, Alireza; Nourbakhsh, Amir

2009-11-30

106

Measurements of the Chemical Composition of Atmospheric Nanoparticles  

NASA Astrophysics Data System (ADS)

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

Smith, Jim

2008-03-01

107

Chemical composition of caesium plasma with simple molecular gas impurities  

NASA Astrophysics Data System (ADS)

The chemical composition of the interelectrode medium of a TEC (thermionic energy converter) with impurities containing carbon, oxygen, and hydrogen was studied using the thermodynamic approach. Condensed cesium carbonate and carbon as well as carbon compounds with the electrode materials W and Mo were shown to be possible within the range of temperatures corresponding to the collector temperatures. Hydrogen effects on the upper limit of the temperature range in which condensed compounds can exist were studied. Hydrogen was shown to affect this limit in a number of ways, depending on the amount of oxygen present in the gap. At high temperatures, the negative ions WO3- or MoO3- may be present in the gap in current-affecting amounts. If a niobium collector is used, it can add carbon and oxygen to form compounds which exist up to emitter temperatures. The compound type is determined by the relative amounts of niobium, carbon, and oxygen. The presence of hydrogen has practically no effect on the system's chemical composition.

Zherebtsov, V. A.; Lebedev, M. A.; Luk'ianov, A. A.; Sobolev, A. A.

108

Chemical Changes  

NSDL National Science Digital Library

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

Jolley, Mr.

2005-10-25

109

Chemical Composition of Titan's lakes: estimates and uncertainties  

NASA Astrophysics Data System (ADS)

Between 2004 and 2007 [?] the instruments of the CASSINI spacecraft, orbiting within the Saturn system, discovered dark patches in the polar regions of Titan. These features are interpreted as hydrocarbon lakes and seas with ethane and methane identified as the main compounds. In this context, we have developed a lake-atmosphere equilibrium model allowing the determination of the chemical composition of these liquid areas present on Titan (see Table 1 for the nominal composition). Elaborated in the frame of the theory of regular solutions, this model is based on uncertain thermodynamic data and precipitation rates of organic species predicted to be present in the lakes and seas that are subject to spatial and temporal variations. Here we explore and discuss the influence of these uncertainties and variations. The errors and uncertainties relevant to thermodynamic data are simulated viaMonte-Carlo simulations. Global Circulation Models (GCM) are also employed in order to investigate the possibility of chemical asymmetry between the south and the north poles, due to differences in precipitation rates. We find that mole fractions of compounds in the liquid phase have a high sensitivity to thermodynamic data used as inputs, in particular molar volumes and enthalpies of vaporization. When we combine all considered uncertainties, the ranges of obtained mole fractions are rather large (up to ! 8500%) but the distributions of values are narrow. The relative standard deviations remain between 10% and ! 300% depending on the compound considered. Compared to other sources of uncertainties and variability, deviation caused by surface pressure variations are clearly negligible, remaining of the order of a few percent up to ! 20%. Moreover no significant difference is found between the composition of lakes located in north and south poles. Because the theory of regular solutions employed here is sensitive to thermodynamic data and is not suitable for polar molecules such as HCN and CH3CN, our work strongly underlines the need for experimental simulations and the improvement of Titan's atmospheric models.

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

2012-09-01

110

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

111

The exotic chemical composition of the Sagittarius dwarf spheroidal galaxy  

NASA Astrophysics Data System (ADS)

Context: The Sagittarius dwarf spheroidal galaxy is the nearest neighbor of the Milky Way. Moving along a short period quasi-polar orbit within the Halo, it is being destroyed by the tidal interaction with our Galaxy, losing its stellar content along a huge stellar stream. Aims: We study the detailed chemical composition of 12 giant stars in the Sagittarius dwarf Spheroidal main body, together with 5 more in the associated globular cluster Terzan 7, by means of high resolution VLT-UVES spectra. Methods: Abundances are derived for up to 21 elements from O to Nd, by fitting lines EW or line profiles against ATLAS 9 model atmospheres and SYNTHE spectral syntheses calculated ad-hoc. Temperatures are derived from (V-I)0 or (B-V)0 colors and gravities from Fe I - Fe II ionization equilibrium. Results: The metallicity of the observed stars is between [Fe/H] = -0.9 and 0. We detected a highly peculiar "chemical signature", with undersolar ? elements, Na, Al, Sc, V, Co, Ni, Cu, and Zn, among others, and overabundant La, Ce, and Nd. Many of these abundance ratios (in particular light-odd elements and iron peak ones) are strongly at odds with what is observed within the Milky Way, so they may be a very useful tool for recognizing populations originating within the Sagittarius dwarf. This can be clearly seen in the case of the globular Palomar 12, which is believed to have been stripped from Sagittarius: the cluster shows precisely the same chemical "oddities", thus finally confirming its extragalactic origin.

Sbordone, L.; Bonifacio, P.; Buonanno, R.; Marconi, G.; Monaco, L.; Zaggia, S.

2007-04-01

112

Chemical compositions and glycemic responses to banana varieties.  

PubMed

Chemical compositions and glycemic indices of four varieties of banana (Musa spp.) (kolikuttu-Silk AAB, embul-Mysore AAB, anamalu-Gros Michel AAA, seeni kesel-Pisang Awak ABB) were determined. Silk, Gros Michel, Pisang Awak and Mysore contained the highest percentages of starch (14%), sucrose (38%), free glucose (29%) and fructose (58%) as a percentage of the total available carbohydrate content respectively. Total dietary fiber contents of four varieties ranged from 2.7 to 5.3%. Glycemic indices of Silk, Mysore, Gros Michel and Pisang Awak were 61 ± 5, 61 ± 6, 67 ± 7, 69 ± 9 and can be categorized as low against white bread as the standard. A single banana of the four varieties elicited a low glycemic load. Thus, consumption of a banana from any of these varieties can be recommended as a snack for healthy or diabetic patients who are under dietary management or pharmacological drugs to regulate blood glucose responses in between meals. PMID:21250902

Hettiaratchi, U P K; Ekanayake, S; Welihinda, J

2011-01-20

113

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

114

Optimum conditions for composites fiber coating by chemical vapor infiltration  

SciTech Connect

A combined analytical and numerical method is employed to optimize process conditions for composites fiber coating by chemical vapor infiltration (CVI). For a first-order deposition reaction, the optimum pressure yielding the maximum deposition rate at a preform center is obtained in closed form and is found to depend only on the activation energy of the deposition reaction, the characteristic pore size, and properties of the reactant and product gases. It does not depend on the preform specific surface area, effective diffusivity or preform thickness, nor on the gas-phase yield of the deposition reaction. Further, this optimum pressure is unaltered by the additional constraint of a prescribed deposition uniformity. Optimum temperatures are obtained using an analytical expression for the optimum value along with numerical solutions to the governing transport equations. These solutions account for both diffusive and advective transport, as well as both ordinary and Knudsen diffusion. Sample calculations are presented for coating preform fibers with boron nitride.

Griffiths, S.K.; Nilson, R.H.

1997-04-01

115

Quantification of aerosol chemical composition using continuous single particle measurements  

NASA Astrophysics Data System (ADS)

Mass concentrations of sulphate, nitrate, ammonium, organic carbon (OC), elemental carbon (EC) were determined from real time single particle data in the size range 0.1-3.0 ?m measured by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) at urban and rural sites in Canada. To quantify chemical species within individual particles measured by an ATOFMS, ion peak intensity of m/z -97 for sulphate, -62 for nitrate, +18 for ammonium, +43 for OC, and +36 for EC were scaled using the number and size distribution data by an Aerodynamic Particle Sizer (APS) and a Fast Mobility Particle Sizer (FMPS). Hourly quantified chemical species from ATOFMS single-particle analysis were compared with collocated fine particulate matter (aerodynamic diameter < 2.5 ?m, PM2.5) chemical composition measurements by an Aerosol Mass Spectrometer (AMS) at a rural site, a Gas-Particle Ion Chromatograph (GPIC) at an urban site, and a Sunset Lab field OCEC analyzer at both sites. The highest correlation was found for nitrate, with correlation coefficients (Pearson r) of 0.89 (ATOFMS vs. GPIC) and 0.85 (ATOFMS vs. AMS). ATOFMS mass calibration factors, determined for the urban site, were used to calculate mass concentrations of the major PM2.5 chemical components at the rural site near the US border in southern Ontario. Mass reconstruction using the ATOFMS mass calibration factors agreed very well with the PM2.5 mass concentrations measured by a Tapered Element Oscillating Microbalance (TEOM, r = 0.86) at the urban site and a light scattering monitor (DustTrak, r = 0.87) at the rural site. In the urban area nitrate was the largest contributor to PM2.5 mass in the winter, while organics and sulphate contributed ~64 % of the summer PM2.5 in the rural area, suggesting a strong influence of regional/trans-boundary pollution. The mass concentrations of five major species in ten size-resolved particle-types and aerosol acidity of each particle-type were determined for the rural site. On a mass basis sulphate and OC rich particle-types (OC-S and OC-S-N) accounted for up to 59 % of the particles characterized and aerosols were weakly acidic in the rural area. This is the first study to estimate hourly quantitative data of sulphate, nitrate, ammonium, OC and EC in ambient particles from scaled ATOFMS single particle analysis; these were closely comparable with collocated high time resolution data of sulphate, nitrate and ammonium detected by AMS and GPIC.

Jeong, C.-H.; McGuire, M. L.; Godri, K. J.; Slowik, J. G.; Rehbein, P. J. G.; Evans, G. J.

2011-07-01

116

Chemical Composition of Titan's lakes: estimates and uncertainties  

NASA Astrophysics Data System (ADS)

Between 2004 and 2007 the instruments of the CASSINI spacecraft, orbiting within the Saturn system, discovered dark patches in the polar regions of Titan. These features are interpreted as hydrocarbon lakes and seas with ethane and methane identified as the main compounds. In this context, we have developed a lake-atmosphere equilibrium model allowing the determination of the chemical composition of these liquid areas present on Titan. The model is based on uncertain thermodynamic data and precipitation rates of organic species predicted to be present in the lakes and seas that are subject to spatial and temporal variations. Here we explore and discuss the influence of these uncertainties and variations. The errors and uncertainties relevant to thermodynamic data are simulated viaMonte-Carlo simulations. Global Circulation Models (GCM) are also employed in order to investigate the possibility of chemical asymmetry between the south and the north poles, due to differences in precipitation rates. We find that mole fractions of compounds in the liquid phase have a high sensitivity to thermodynamic data used as inputs, in particular molar volumes and enthalpies of vaporization. When we combine all considered uncertainties, the ranges of obtained mole fractions are rather large (up to ? 8500%) but the distributions of values are narrow. The relative standard deviations remain between 10% and ? 300% depending on the compound considered. Compared to other sources of uncertainties and variability, deviation caused by surface pressure variations are clearly negligible, remaining of the order of a few percent up to ? 20%. Moreover no significant difference is found between the composition of lakes located in north and south poles. Because the theory of regular solutions employed here is sensitive to thermodynamic data and is not suitable for polar molecules such as HCN and CH3CN, our work strongly underlines the need for experimental simulations and the improvement of Titan's atmospheric models.

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

2012-09-01

117

Chemical composition of precipitation at Long Island, NY  

Microsoft Academic Search

Chemical analyses were performed on 387 sequential precipitation samples, both rain and snow, collected at Brookhaven National Laboratory, Long Island, New York, on 96 different days during the period from October 1983 to June 1985. The collection time for each individual sample was typically 30 min. The chemical species determined and the volume-weighted average and maximum concentrations (in parentheses) in

Yin-Nan Lee; Ji Shen; Paul J. Klotz

1986-01-01

118

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

PubMed

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

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

2011-02-15

119

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

120

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

121

The chemical composition of main sequence stars. [Milky way  

Microsoft Academic Search

This review examines some recent observational enquires into the chemical evolution of the Galaxy. After brief discussions of the galactic abundance gradient and the age-metallicity relationship, the major part of the review is devoted to a compilation and discussion of the variation of the abundances of the chemical elements in disk and halo stars; i.e., the run of (el\\/Fe) vs

1989-01-01

122

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

123

To measure the chemical composition of a Near Earth Object  

NASA Astrophysics Data System (ADS)

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

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

124

Physical Morphology and Quantitative Characterization of Chemical Changes of Weathered PVC/Pine Composites.  

National Technical Information Service (NTIS)

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifi...

A. G. McDonald J. S. Fabiyi

2009-01-01

125

Rainwater chemical composition at two sites in Central Mexico  

NASA Astrophysics Data System (ADS)

Chemical analyses were performed on rainwater samples collected at the National Autonomous University of Mexico (UNAM) in Mexico City and at a wooded site, Rancho Viejo (RV) in the State of Mexico, for the periods 1994 2000 and 1994 1999, respectively. At UNAM, rainwater was collected for the entire rainy season period each year, while at RV, technical considerations limited collection to weekends only. The results showed large variations in rainwater chemical composition in most years, mainly because of the variability of meteorological conditions and also because of changes in source emissions. Sulfates and NH4+ showed higher annual volume-weighted mean concentrations (VWMC) in both sites. At UNAM, the maximum annual VWMC for SO42- occurred in March and the minimum in July and August. Lower concentrations of almost all ions were found at RV; however, the H+ concentration was higher at this site. The pH in Mexico City, calculated from the annual VWMC of H+, was 4.95, which is a little higher than pH values reported in some other countries. Despite the fact that sulfate and NO3- concentrations were lower at RV, the pH was lower. Air-mass back trajectories were calculated for individual concentrations of SO42-, H+, NH4+, Ca2+, and Mg2+, observed at each sampling site for weekend data. At RV, sulfate concentrations were higher when air-mass back trajectories indicated a wind flow from Mexico City and Toluca at 1000 MAGL (meters above ground level) and 3000 MAGL. The hydrogen ion exhibited the same behavior. Calcium and Mg2+ concentrations were also higher when the wind blew from urban areas at 1000 and 3000 MAGL. At UNAM, H+ concentration was lower and Ca2+ and Mg2+ were higher when wind blew from the northern sector of the city at 1000 and 3000 MAGL. In UNAM, the NO3-/SO42- and NH4+/SO42- ratios were 0.5 and 1.09 in 1994 and 0.86 and 1.64 in 2000, respectively, indicating a decrease in SO2 emissions resulting from the change of fuel oil to gas fuel. The SO42-/Ca2+ ratio was significantly lower at the UNAM site (1.82) compared to RV (5.36), and the SO42-/H+ ratio was significantly higher at the UNAM site (6.77) compared to RV (2.01). The Spearman's rho correlation between ionic concentrations indicated a positive correlation in most cases (p < 0.05) for data from UNAM and RV. The multiple regression correlation analysis to predict H+ concentration in Mexico City showed that NO3-, NH4+, SO42-, and Ca2+ contributed 23.2%, 20.9%, 8.0%, and 6.1%, respectively, to the H+ prediction, while Cl- plus Na+ plus K+ only contributed 2.2%, and Mg2+ did not contribute. Sea-salt contribution to rainwater chemical composition was negligible with any wind direction at both levels. Excess sulfate (non-sea-salt sulfate) represented 98.7% of the total sulfate in rainwater collected during weekends at RV and 98.6% for weekend and annual rain samples at UNAM.

Báez, A. P.; Belmont, R. D.; García, R. M.; Torres, M. C. B.; Padilla, H. G.

2006-04-01

126

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

2011-03-25

127

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.

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

2012-01-01

128

Chemical composition of some seaweed from Mediterranean Sea coast, Egypt.  

PubMed

This study pointed to the assessment of the chemical composition (F, Ca, Mg, Na, K, Fe, Mn, Zn, Cu, Ni, Co, Cr, Cd, and carbohydrate) of different marine seaweeds (red, green, and brown) from the Egyptian Mediterranean Sea coast. The results showed that green seaweeds supplied better calcium sources than the red and brown ones. Also, red and brown seaweeds showed higher averages of Na and K than that in green species and these seaweeds could play an important role in the electrolyte balance in humans. On the other hand, green seaweeds gave the highest average carbohydrate concentration; thus, these green species could be used as a source of polysaccharides. Ion quotient values for almost seaweed species were between 1.4 and 4.0, so they can reduce hypertension, preeclampsia, and heart disease in human beings. Interestingly, the calculated hazard quotient of elements was below 1. Accordingly, these seaweed species were of high quality and safety and might be used in the field of nutrition. PMID:23212555

El-Said, Ghada F; El-Sikaily, Amany

2012-12-05

129

Chemical vapor infiltration of TiB[sub 2] composites  

SciTech Connect

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

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

1993-01-01

130

Chemical vapor infiltration of TiB{sub 2} composites  

SciTech Connect

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

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

1993-01-01

131

Chemical composition and antibacterial activity of Gongronema latifolium.  

PubMed

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

Eleyinmi, Afolabi F

2007-05-01

132

Chemical and radioactive composition of bulk deposition in Málaga (Spain)  

NASA Astrophysics Data System (ADS)

Chemical and radioactive composition of bulk deposition samples, which were collected monthly over a 5 year period (January 2007 until 31 December 2011) at a site located 30 m.a.l. in Málaga (4°28? 8?W; 36°43? 40?N) have been analysed. All samples were analysed for pH, major ions and gamma radionuclides. The average pH of bulk deposition was 6.4. Cl- and SO were the main anions, while Ca+ and Na+ were the main cations. Significant correlations were found in soil-derived species among Ca2+, Mg2+ and K+ and sea-salt species between Na+ and Cl-. Other relatively good correlations were also observed between acidic anions (SOandNO) and crustal-derived cations (Ca2+, Na+, K+). Sources of the major ions were assessed based on the enrichment factor method. The radionuclides present in all samples are 7Be and 210Pb and 40K appears in 50% of the samples. Relatively poor correlations were observed between the specific activities of gamma radionuclides and the major ions. The temporal variations of major ions and radionuclides exhibit similar seasonal behaviour with low values in winter-autumn months and maximum values in spring-summer months. The fluxes of major ions and gamma radionuclides have been discussed with meteorological factors controlling depositions.

Dueñas, C.; Fernández, M. C.; Gordo, E.; Cañete, S.; Pérez, M.

2012-12-01

133

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.

Magalhaes, Karina Teixeira; de Melo Pereira, Gilberto Vinicius; Campos, Cassia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-01-01

134

The modeling of the chemical composition and structural transformations in electrode pitches  

SciTech Connect

A new method is proposed for studying the composition and physicochemical transformations in pitches - chemical modeling. Correlation relationships have been found between thermochemical properties and composition. A chemical classification of electrode pitches on statistical models is given. The structural transformations taking place on the thermostating of medium-temperature pitches have been shown.

Turenko, F.P.; Bochkareva, N.N.

1984-01-01

135

Chemical composition and antioxidant activities of the essential oil and methanol extracts of Psammogeton canescens  

Microsoft Academic Search

This study is outlined to probe the chemical composition of essential oil and in vitro antioxidant activity of the essential oil and methanol extracts of Psammogeton canescens. The chemical composition of the hydrodistilled essential oil of the aerial parts of P. canescens was analyzed by GC and GC\\/MS. The main constituents of the oil were found to be ?-bisabolene (33.35%),

Mohammad Bagher Gholivand; Mehdi Rahimi-Nasrabadi; Hossein Batooli; Abdolrasoul H. Ebrahimabadi

2010-01-01

136

The role of aerosol composition in the chemical processes in the atmosphere  

Microsoft Academic Search

The importance of airborne particles and their composition in chemical processes in the atmosphere is discussed briefly in the first part of the paper. In the second part, the results of the study of chemical composition and reactivity of aerosols in heterogeneous aqueous systems (laboratory and field) obtained by our research group are presented. The kinetics of oxidation of S(IV)

Mirko Bizjak; Irena Grgi?; Vida Hudnik

1999-01-01

137

ACCURATE DETERMINATION OF CHEMICAL COMPOSITION OF URINARY CALCULI BY SPIRAL COMPUTERIZED TOMOGRAPHY  

Microsoft Academic Search

PurposeChoice of efficacious clinical management of symptomatic renal calculi can be facilitated by ascertaining the precise chemical composition of the calculus. Spiral computerized tomography (CT) is becoming a frequently used radiographic examination to establish the diagnosis and severity of calculus disease. Our objective for this study was to determine the precision of spiral CT in identifying the chemical composition of

MOHAMMAD R. MOSTAFAVI; RANDY D. ERNST; BRIAN SALTZMAN

1998-01-01

138

Changes in chemical wax composition of three different apple ( Malus domestica Borkh.) cultivars during storage  

Microsoft Academic Search

The effects of year, picking date and storage conditions on the chemical composition of the wax layer of three apple cultivars (‘Jonagold’, ‘Jonagored’ and ‘Elstar’) were investigated by means of GCMS and multivariate statistical techniques. Wax of apples with different surface characteristics also differed in chemical composition. Controlled atmosphere (CA) storage and subsequent shelf life affected wax properties and caused

Els A. Veraverbeke; Jeroen Lammertyn; Stijn Saevels

2001-01-01

139

Chemical composition and nutritional value of Mexican varieties of chickpea ( Cicer arietinum L.)  

Microsoft Academic Search

Chemical composition and protein quality of the main chickpea varieties cultivated in Mexico were determined. The raw and cooked chickpeas analyzed were: Surutato, Surutato 77, Sonora, Sonora 80, Porquero, Macarena, Breve Duro and a mixture of broken seeds used mainly for animal feeding. The chemical composition of the raw chickpea studied was very similar; the average values of the nutrients

Angela Sotelo; Fernando Flores; Miguel Hernández

1987-01-01

140

Lunar clinopyroxenes: chemical composition, structural state, and texture.  

PubMed

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) augitepigeonite 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 Ti(4+) + 2Ai and 2Si. Our evidence suggests that a chemically inhomogeneous subcalcic C2/c augite was the only primary pyroxene from which pigeonite later exsolved. PMID:17781523

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

1970-01-30

141

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

Microsoft Academic Search

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

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

2010-01-01

142

Brazilian Propolis: Correlation Between Chemical Composition and Antimicrobial Activity  

PubMed Central

The chemical composition of ethanol extracts from samples of Brazilian propolis (EEPs) determined by HPLC and their activity against Trypanosoma cruzi, Staphylococcus aureus, Streptococcus pneumoniae, Klebisiella pneumoniae, Candida albicans, Sporothrix schenckii and Paracoccidioides brasiliensis were determined. Based on the predominant botanical origin in the region of samples' collection, the 10 extracts were separated into three groups: A (B. dracunculifolia + Auraucaria spp), B (B. dracunculifolia) and C (Araucaria spp). Analysis by the multiple regression of all the extracts together showed a positive correlation, higher concentrations leading to higher biological effect, of S. aureus with p-coumaric acid (PCUM) and 3-(4-hydroxy-3-(oxo-butenyl)-phenylacrylic acid (DHCA1) and of trypomastigotes of T. cruzi with 3,5-diprenyl-4-hydroxycinnamic acid derivative 4 (DHCA4) and 2,2-dimethyl-6-carboxyethenyl-2H-1-benzopyran (DCBEN). When the same approach was employed for each group, due to the small number of observations, the statistical test gave unreliable results. However, an overall analysis revealed for group A an association of S. aureus with caffeic acid (CAF) and dicaffeoylquinic acid 3 (CAFQ3), of S. pneumoniae with CAFQ3 and monocaffeoylquinic acid 2 (CAFQ2) and of T. cruzi also with CAFQ3. For group B, a higher activity against S. pneumoniae was associated DCBEN and for T. cruzi with CAF. For group C no association was observed between the anitmicrobial effect and any component of the extracts. The present study reinforces the relevance of PCUM and derivatives, especially prenylated ones and also of caffeolyquinic acids, on the biological activity of Brazilian propolis.

Salomao, Kelly; Pereira, Paulo Roberto S.; Campos, Leila C.; Borba, Cintia M.; Cabello, Pedro H.; Marcucci, Maria Cristina

2008-01-01

143

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

144

Chemical composition and origin of the Acapulco meteorite  

Microsoft Academic Search

New chemical data for both whole-rock and individual mineral samples from the Acapulco meteorite are reported. Results of instrumental neutron activation analysis (INAA) of bulk samples show large variation in La, Cr, Se, and Fe contents reflecting inhomogeneous distribution of the corresponding host phases: phosphate, chromite, sulfide, and FeNi metal. In contrast, Mn, Sc, and Na contents are uniformly distributed

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

1995-01-01

145

Chemical composition of Monsoon deposition in the Everest region  

Microsoft Academic Search

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

S Valsecchi; C Smiraglia; G Tartari; S Polesello

1999-01-01

146

Elemental composition method for computation and analysis of simultaneous chemical and phase equilibrium  

Microsoft Academic Search

An elemental composition method for computation and analysis of simultaneous chemical and phase equilibrium (CPE) of non-ideal\\u000a mixtures is proposed. The concept of element is defined, the relationship between component composition and elemental composition\\u000a is derived, and the concept of elemental potential and its physical meaning are further cleared from the view point of thermodynamics.\\u000a The relationship between chemical potential

Jinqing Lin; Haoran Li; Shijun Han

2000-01-01

147

Effect of chemical composition of intergranular glass on superplastic compressive deformation of ?-silicon nitride  

Microsoft Academic Search

The effect of chemical composition of Y2O3–Al2O3–SiO2-based intergranular glass on superplastic deformation of ?-Si3N4 was studied by compression tests at 1873K. All hot isostatically pressed Si3N4 materials had essentially the same microstructure and the same amount of glass phase, which was different in composition only. The relation between flow stress and glass composition qualitatively corresponded to the effect of chemical

E. Narimatsu; Y. Shinoda; T. Akatsu; F. Wakai

2006-01-01

148

Quantification of aerosol chemical composition using continuous single particle measurements  

Microsoft Academic Search

Mass concentrations of sulphate, nitrate, ammonium, organic carbon (OC), elemental carbon (EC) were determined from real time single particle data in the size range 0.1-3.0 mum measured by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) at urban and rural sites in Canada. To quantify chemical species within individual particles measured by an ATOFMS, ion peak intensity of m\\/z -97 for sulphate,

C.-H. Jeong; M. L. McGuire; K. J. Godri; J. G. Slowik; P. J. G. Rehbein; G. J. Evans

2011-01-01

149

Quantification of aerosol chemical composition using continuous single particle measurements  

Microsoft Academic Search

Mass concentrations of particulate matter (PM) chemical components were determined from data for 0.3 to 3.0 mum particles measured by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) data at an urban and rural site. Hourly-averaged concentrations of nitrate, sulphate, ammonium, organic carbon, and elemental carbon, estimated based on scaled ATOFMS peak intensities of corresponding ion marker species, were compared with collocated

C.-H. Jeong; M. L. McGuire; K. J. Godri; J. G. Slowik; P. J. G. Rehbein; G. J. Evans

2011-01-01

150

Regulating continent growth and composition by chemical weathering  

Microsoft Academic Search

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

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

2008-01-01

151

Regulating continent growth and composition by chemical weathering.  

PubMed

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

2008-03-24

152

Regulating continent growth and composition by chemical weathering  

USGS Publications Warehouse

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

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

2008-01-01

153

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

154

Fog water chemical composition in different geographic regions of Poland  

NASA Astrophysics Data System (ADS)

The fog water samples were collected with the use of both passive and active fog collectors during 2005-2006 at 3 sites: lowland in northern Poland (Borucino; 186 m a.s.l.), valley basin in southern Poland (Zakopane; 911 m a.s.l.) and mountain top (Szrenica Mt.; 1330 m a.s.l.) in south-western Poland. For all daily samples (Borucino—25; Zakopane—4 and Szrenica—155), electric conductivity, pH, and concentrations of some anions: Cl -, F -, Br -, NO 2-, NO 3-, SO 42-, PO 43-and cations: NH 4+, Ca 2+, K +, Na + and Mg 2+ were measured. The selected ions were determined using ion suppressed chromatography (IC). Fog consists of a specific type of atmospheric phenomena. Results obtained on the basis of analysis of suitable fog samples can be treated as a source of valuable information on the chemistry of the atmosphere. Statistical analysis revealed significant differences depending on region, altitude, local morphology and, last but not least, fog origin. A distinct contrast is evident in the concentration and chemical composition between lowland radiation fog (represents lower layers of the atmosphere which are more influenced by continental emissions) versus orographic slope fog represented by a summit station, Mt Szrenica. It is partly induced by a distinction in weather conditions favouring fog existence, height of fog formation and its microphysical parameters. Acidity was associated with high concentrations of excess sulphate and nitrate in the fog water samples. Ammonium and calcium concentrations represent the most important neutralizing inputs. Collected cloud water at Szrenica Mt. includes solute contributions from emission sources located at much larger upwind distances. The fact that 95% of fog/cloud deposition is concentrated during SW-W-NW-N-NE, atmospheric circulation exerts an influence on the environmental quality of montane forests in the Sudety Mts. At numerous conspicuous convex landforms, where fog/cloud deposition becomes at least as important as wet deposition via atmospheric precipitation, a distinct difference in the health of coniferous forests is clearly visible, with the areas of the NW aspect being the worst affected, contrary to SE slopes with relatively healthy forest stands.

B?a?, Marek; Polkowska, ?aneta; Sobik, Mieczys?aw; Klimaszewska, Kamila; Nowi?ski, Kamil; Namie?nik, Jacek

2010-03-01

155

Chemical Composition of Polymer Surfaces Imaged by Atomic Force Microscopy and Complementary Approaches  

Microsoft Academic Search

In this article we review the recent developments in the field of high resolution lateral mapping\\u000a of the surface chemical composition of polymers by atomic force microscopy (AFM) and other complementary\\u000a imaging techniques. The different AFM approaches toward nanometer scale mapping with chemical sensitivity\\u000a based on chemical force microscopy (CFM) are discussed as a means to unravel, for instance, the\\u000a lateral

G. Julius Vancso; Henrik Hillborg; Holger Schönherr

2005-01-01

156

Chemical composition of landfill leachate in a karst area with a Mediterranean climate (Marbella, southern Spain)  

Microsoft Academic Search

Between March 1994 and April 1997, the physical and chemical parameters and chemical composition of the urban solid waste\\u000a leachate of the Marbella landfill (southern Spain) were determined. The data obtained show an ammonium and sodium chloride\\u000a and bicarbonate type, a pH>7 and high mineralization, effectively described by the following parameters: Na+, K+, NH4\\u000a +, Cl– and alkalinity. The chemical

I. Vadillo; F. Carrasco; B. Andreo; A. García de Torres; C. Bosch

1999-01-01

157

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

Microsoft Academic Search

Frost flowers have been proposed to be the major source of sea-salt aerosol to the atmosphere during polar winter and a source of reactive bromine during polar springtime. However little is known about their bulk chemical composition or microstructure, two important factors that may affect their ability to produce aerosols and provide chemically reactive surfaces for exchange with the atmosphere.

Laura Alvarez-Aviles; William R. Simpson; Thomas A. Douglas; Matthew Sturm; Donald Perovich; Florent Domine

2008-01-01

158

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

Microsoft Academic Search

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

Terry Plank; Charles H. Langmuir

1998-01-01

159

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

Microsoft Academic Search

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

Andrea Versari; Giuseppina Paola Parpinello; Sergio Galassi

2002-01-01

160

Proposals for VIRA (Venus International Reference Atmosphere): Chemical composition of atmosphere below 100 KM  

Microsoft Academic Search

Tables of data indicating the chemical composition of the Venus' atmosphere are given. The data came from mass-spectroscopy, gas chromatography, optical spectroscopy in the deep layers of the atmosphere, and gas analysis by mean of specific chemical reactions. Measurements from the Venera and Pioneer probes are given.

V. I. Moroz; V. G. Istomin; L. M. Mukhin

1983-01-01

161

Simulation of composite fatigue resulting from chemical attack of bridging fibers  

Microsoft Academic Search

A numerical simulation that predicted fatigue-like behavior resulting from chemical attack of bridging fibers in a cracked composite was developed. Chemical attack of bridging fibers led to mechanical failure of bridging fibers, and a corresponding reduction in the closure stress. As the closure stress decreased, the crack grew to form new bridging fibers. Crack growth rates were predicted to increase

D. N. Coon; A. S. Motkur

2000-01-01

162

Dependence of the burning rate of a composite propellant on the chemical structure of the fuel  

Microsoft Academic Search

The question of the relationship between burning rate and chemical structure has received almost no attention, although there are qualitative indications that the burning does depend on the chemical structure of the fuel [2]. We have investigated the burning rates of composite propellants based on ammonium perchlorate (AP) and fuels containing various functional groupings. The calorific value has been experimentally

L. D. Romodanova; V. I. Pepekin; A. Ya. Apin; P. F. Pokhil

1970-01-01

163

Effects of Chemical Weathering on TIR-Derived Bulk Compositions From Deconvolution Models of Mineral Mixtures  

Microsoft Academic Search

The Martian surface may be chemically altered on regional scales. Thermal infrared (TIR) spectroscopy and spectral deconvolution are commonly used to determine mineral abundances of the surface. Chemically weathered surfaces tend to be intimate mixtures of igneous minerals and fine-grained alteration products. To understand how alteration products affect deconvolution models of TIR spectra and model-derived bulk compositions, we measured TIR

E. B. Rampe; M. D. Kraft; T. G. Sharp; A. D. Rogers

2007-01-01

164

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

Microsoft Academic Search

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

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

2010-01-01

165

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

Microsoft Academic Search

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

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

2000-01-01

166

Salinity Variations and Chemical Compositions of Waters in the Frio Formation, Texas Gulf Coast. Annual Report.  

National Technical Information Service (NTIS)

Waters produced from sandstone reservoirs of the deep Frio Formation exhibit spatial variations in chemical composition that roughly coincide with the major tectonic elements (Houston and Rio Grande Embayments, San Marcos Arch) and corresponding depositio...

R. A. Morton C. M. Garrett J. S. Posey J. H. Han L. A. Jirik

1981-01-01

167

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...

168

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...

169

The effects of drying temperature on chemical composition and nutritive value of some tropical fodder shrubs  

Microsoft Academic Search

The effects of drying temperature on chemical composition and nutritive value of leaves of the shrub legumes Acacia angustissima (Miller) Kuntze, Calliandra calothyrsus Meissn and Leucaena leucocephala (Lam.) de Wit were determined in two studies in Zimbabwe. In the first study, the effects of shade-, sun- and oven-drying\\u000a leaves on chemical composition and protein precipitation capacity of tannin extracts were

L. Hove; L. R. Ndlovu; S. Sibanda

2003-01-01

170

The chemical composition of throughfall beneath oak, birch and pine canopies in Northwest Germany  

Microsoft Academic Search

The chemical composition of rainwater is altered upon its passage through tree canopies. In order to investigate how rainwater\\u000a chemistry is affected by canopy-dependent processes in characteristic forest types of Northwest German sandy lowland regions\\u000a – oak–birch-forests, Betula pubescens Ehrh. swamp forests, and stands of Pinus sylvestris L. – comparative studies on the chemical composition of throughfall were carried out

Martina Herrmann; Jürgen Pust; Richard Pott

2006-01-01

171

Correlation between dielectric properties and chemical composition of the tourmaline single crystals  

NASA Astrophysics Data System (ADS)

Dielectric responses were studied on piezoelectric tourmaline single crystals of widely varying chemical composition from different geological origins. The dielectric constants at constants stress, and dissipation factor were measured as a function of frequency (100-1000 kHz) using method of substitution. A correlation between two independent dielectric constants (along and perpendicular to crystallographic c-axis) is observed, and dependence of dielectric constants on chemical composition is presented.

Shekhar Pandey, Chandra; Jodlauk, Sven; Schreuer, Jürgen

2011-10-01

172

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

Microsoft Academic Search

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

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

1994-01-01

173

Sisal\\/Carbon Fibre Reinforced Hybrid Composites: Tensile, Flexural and Chemical Resistance Properties  

Microsoft Academic Search

The variation of mechanical properties such as tensile and flexural properties of randomly oriented unsaturated polyester\\u000a based sisal\\/carbon fibre reinforced hybrid composites with different fibre weight ratios have been studied. The chemical resistance\\u000a test of these hybrid composites to various solvents, acids and alkalies were studied. The effect of NaOH treatment of sisal\\u000a fibres on the tensile, flexural and chemical

P. Noorunnisa Khanam; H. P. S. Abdul Khalil; M. Jawaid; G. Ramachandra Reddy; C. Surya Narayana; S. Venkata Naidu

2010-01-01

174

Chemical Biology\\/ Chemical Genetics\\/ Chemical Genomics: Importance of Chemical Library  

Microsoft Academic Search

A new field of science, chemical biology\\/ chemical genetics\\/ chemical genomics (cb\\/cg\\/cg) has emerged since the late 1990's, especially in the United States. The NIH Roadmap agenda, Molecular Libraries Screening Center Network (MLSCN), became a drive force to push cb\\/cg\\/cg forward. Cb\\/cg\\/cg studies consist of three methodologies, chemical libraries with small molecules, high-throughput screenings, and computational databases. In this review,

Fumihiko Kugawa; Masaru Watanabe; Fuyuhiko Tamanoi

2007-01-01

175

Chemical Composition of Stars with Extrasolar Planetary Systems  

NASA Astrophysics Data System (ADS)

In this article we review surface abundances in stars which host planetary systems. Recent spectroscopic studies of stars with and without planetary systems have concluded that stars which host giant planets are more metal-rich than those without planets. We discover more subtle trends of different chemical elements as the number of detected exoplanets continues to grow. In particular, Li seems to be depleted in planet host stars. Knowledge of precise abundances of oxygen and carbon may help to understand the structure of extrasolar planets. However, in most cases, the abundance trends of planet-host stars are very similar to those of the comparison sample. Possible explanations for the abundance anomalies or the correlation between [Fe/H] and the presence of giant planets have certain implications for planetary formation and evolution theory, Galactic chemical evolution, and astrobiology. The latest results indicate that some metals other than iron may also have an important contribution to planet formation if the amount of iron is low. Stars that host terrestrial planets, that can be found at low-iron regime, are mostly enhanced by ?-elements.

Israelian, G.; Delgado-Mena, E.; Adibekyan, V.

2013-04-01

176

Chemical composition and biological activity of Citrus jambhiri Lush.  

PubMed

The fresh peel of Citrus jambhiri was extracted with aqueous methanol and the residue was fractionated using light petroleum, chloroform and ethyl acetate. The constituents of the extracts were separated by column chromatography employing solvents of different polarity. The chemical structure of the isolated compounds was then identified by MS and NMR. Column chromatography of the petroleum fraction resulted in the isolation of nobiletin, 5-O-demethylnobiletin, tangeretin, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, 3,5,6,7,8,3',4'-heptamethoxyflavone, and a mixture of ?-sitosterol and stigmasterol. The chloroform fraction afforded 6-demethoxynobiletin, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, limonin and nomilin. The flavonoid glycosides naringin, hesperidin and neohesperidin were isolated from the ethyl acetate fraction. The chemical structure of the isolated compounds was established by MS and NMR (APT, COSY, HSQC, HMBC, and NOESY). LC-ESI-MS analysis of the ethyl acetate fraction afforded eight flavonoid glycosides, while the dichloromethane fraction of the defatted seeds contained seven limonoid aglycones. The chloroform fraction exerted the strongest DPPH(?) free radical scavenging activity in comparison to other fractions. The petroleum fraction showed a significant inhibition of lipoxygenase indicating an anti-inflammatory action (IC(50) 29±1?g/mL). Some of the isolated polymethoxyflavones exhibited strong cytotoxicity against COS7, HeLa and Caco-2 cell lines. PMID:23140678

Hamdan, Dalia; El-Readi, Mahmoud Zaki; Tahrani, Ahmad; Herrmann, Florian; Kaufmann, Dorothea; Farrag, Nawal; El-Shazly, Assem; Wink, Michael

2011-01-08

177

Chemical separations using shell and tube composite polyphophazene membranes  

SciTech Connect

Several applications of modular shell and tube polyphosphazene coated membrane units are reported in this paper. These modules were used to measure the mixed-gas separation properties of poly(bis(phenoxy)phosphazene) based polymers on a larger scale. Transport behavior was determined using the variable volume technique. The test gas mixture was SO{sub 2}/N{sub 2} at temperatures between 80{degrees}C and 270{degrees}C. Transport of these gases was found to be a sorption controlled process. Several organic-aqueous and organic-organic separations have been performed using the polyphophazene coated shell and tube modules. The separations include: methylene chloride/water, acetic acid/water, isopropyl alcohol/water, glycerol/water, and hexane/soy oil. The membranes were prepared using slip casting techniques. The results of these studies show that polyphosphazene membranes can effectively be used to separate acid gases and organic chemicals from various waste streams in harsh, chemically aggressive environments.

Peterson, E.S.; Stone, M.L.; Orme, C.J. [Idaho National Engineering Laboratory, Idaho Falls, ID (United States)

1995-04-01

178

The Chemical Equilibrium Problem.  

National Technical Information Service (NTIS)

It has long been known that the problem of determining the equilibrium composition of a solution of chemically reacting species could be formulated as a constrained minimum problem. Previous methods for solving the chemical equilibrium problem in this for...

J. H. Bigelow

1968-01-01

179

Chemical Structural Aging Effects.  

National Technical Information Service (NTIS)

This program is determining the individual chemical rate processes that govern the aging of ANB-3066 propellant, and it is attempting to establish the effect of chemical (compositional) changes upon the system's mechanical response to enable better utiliz...

G. E. Myers A. B. Tipton

1972-01-01

180

Tunnelling conductivity in conducting polymer composites: a manifestation of chemical interaction  

NASA Astrophysics Data System (ADS)

Charge transport is studied in conducting composites of polyaniline and cis-1,4-polyisoprene (rubber). Films of different compositions are prepared by the solution route that are easily compressible under low pressure. Electrical conductivity is measured across the film thickness with the applied pressure. The results clearly indicate that conductivity is dominated by quantum tunnelling of charge carriers between conducting particles through an insulating barrier for all compositions. These findings are attributed to a strong chemical interaction between the conducting and non-conducting phases. It is demonstrated that such chemical interaction is a vital phenomenon in controlling charge transport of composites.

Kalasad, M N; Rabinal, M K

2009-03-01

181

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

182

Does forest fire effect chemical composition of surface water  

SciTech Connect

Chemical Data for stream drainages in Yellowstone National Park area have been examined for trends associated with the 1988 burn. Limited pre-fire data make assessment difficult. Data from the Snake River (at maximum recorded discharge) suggest that TDS decreases, total Nitrogen remains constant and total Phosphorus increases from pre-fire (and very dry conditions) to post-fire (and more normal conditions). To test these apparent trends post-fire data from adjacent valleys (Jones Creek, burned; Crow Creek, unburned) were compared. Each shows a decrease in TDS, similar nearly constant total Nitrogen and an increase in total Phosphorus. Although year to year changes in surface water seem greater from the burned valley, the data from the unburned valley show similar trends. Therefore these data do not clearly distinguish trends resulting solely from the burn.

Sanders, A.T. (Illinois State Univ., Normal, IL (United States). Dept. of Geography and Geology)

1992-01-01

183

Direct Monte Carlo simulation of the chemical equilibrium composition of detonation products  

SciTech Connect

A new Monte Carlo simulation method has been developed by the author which gives the equilibrium chemical composition of a molecular fluid directly. The usual NPT ensemble (isothermal-isobaric) is implemented with N being the number of atoms instead of molecules. Changes in chemical composition are treated as correlated spatial moves of atoms. Given the interaction potentials between molecular products, ``exact`` EOS points including the equilibrium chemical composition can be determined from the simulations. This method is applied to detonation products at conditions in the region near the Chapman- Jouget state. For the example of NO, it is shown that the CJ detonation velocity can be determined to a few meters per second. A rather small change in cross potentials is shown to shift the chemical equilibrium and the CJ conditions significantly.

Shaw, M.S.

1993-06-01

184

Calculations of the Chemical Composition of the Sacramento Urban Plume  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

185

Measurement of gas transport through fiber preforms and densified composites for chemical vapor infiltration  

Microsoft Academic Search

Gas transport via pressure-driven permeation or via concentration-driven diffusion is a key step in the chemical vapor infiltration (CVI) process. This paper describes methods for the measurement of these properties for CVI preforms and partially infiltrated composites. Results are presented for Nicalon-fiber cloth layup preforms and composites, Nextel-fiber braid preforms and composites, and a Nicalon-fiber three-dimensional (3-D) weave composite. The

T. L. Starr; N. Hablutzel

1998-01-01

186

Optical density and chemical composition of microfilled and microhybrid composite resins.  

PubMed

This study evaluated the optical density of two microfilled and two microhybrid resins, as well as the composition of these materials with regard to their optical density. Cavities prepared in 12 2-mm- or 4-mm-thick acrylic plastic plates were filled with Z250 (3M-ESPE), A110 (3M-ESPE), Charisma (Heraeus-Kulzer) and DurafillVS (Heraeus-Kulzer). The resin increments (2-mm-thick) were light-cured for 40 s. Three 0.12-s radiographic exposures were made of each #2 acrylic plastic plate. DenOptix system optical plates were used to obtain the digital images. Three readings of the composite resin surface were made in each radiograph, totalizing 216 readings. The mean of highest and lowest grey-scale values was obtained. Two specimens of each composite resin were prepared for SEM analysis of the chemical elements related to optical density, using energy dispersive x-ray analysis (EDX). The results were subjected to Shapiro-Wilk's test, ANOVA, Tukey's test at 1% level of significance and Pearson's correlation. The mean grey-scale values at 2 mm and 4 mm were: Z250 = 154.27a and 185.33w; A110 = 46.77b and 63.05y; Charisma = 163.40c and 200.46z; DurafillVS = 43.92b and 58.99x, respectively. Pearson's test did not show any positive correlation between optical density and percentage weight of optical density chemical elements. It was concluded that the microhybrid resins had higher optical density means than the microfilled resins; among the evaluated resins, Charisma had the highest optical density means. PMID:19089205

Braun, Ana Paula; Grassi Soares, Clarissa; Glüer Carracho, Helena; Pereira da Costa, Nilza; Bauer Veeck, Elaine

187

Chemical composition of atmospheric aerosols between Moscow and Vladivostok  

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

188

[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

189

Chemical Composition and Antigenic Structure of Cell Walls of Corynebacterium, Mycobacterium, Nocardia, Actinomyces and Arthrobacter  

Microsoft Academic Search

14 comparison has been made between the chemical composition of the cell walls of strains from the genera Corynebucterizcm, Alycobacterium, Nocardia, Actiwmycrs and Arthrobacter, and the antigenic composition of the same cell-wall fractions as judged by an agglutination test. ,4 common antigenic component was identified in all those strains of' corynchacteria, mycohacteria and nocardias which have arabinose and galactose as

C. S. Cummins; E. Lopidon

1962-01-01

190

Influence of Chemical Composition on the Physical Characteristics of Paving Asphalts  

Microsoft Academic Search

The simplest general compositional model considers asphalt to be made up of asphaltenes, heavy oils, and resins. In the present study the extent of similarity between the properties and composition of various types of asphalt obtained from different sources has been carefully explored. It shows how ductility, penetration, and softening point are related to the chemical nature of paving asphalts

L. O. Oyekunle

2007-01-01

191

Chemical composition of extracted dried olive pomaces containing two and three phases  

Microsoft Academic Search

The chemical composition of extracted dried olive pomaces, obtained from extraction of systems containing two and three phases, was similar. The main component was fibre, with values above 70% in both systems. Nitrogen values and extractability was low for both systems, although in vitro protein digestibility was high (75–80%). Amino acid composition was balanced except for lysine. The isoelectric point

A. Clemente; J. Vioque; J. Bautista; F. Millán

1997-01-01

192

Influence of riming on the chemical composition of snow in winter orographic storms  

Microsoft Academic Search

The chemical composition of surface snow and rime ice has been measured in a winter mountain setting for the purpose of identifying the principal scavenging mechanisms. The sitting permitted the results to be interpreted with minimal consideration of below-cloud scavenging processes and close comparison of the snow and rime ice compositions. The concentrations of all major ions in the snow

David L. Mitchell; Dennis Lamb

1989-01-01

193

Chemical composition of cometary ice and grain, and origin of comets  

Microsoft Academic Search

The chemical composition of the ice and grains in a cometary nucleus is discussed by applying the condensation theory. The equilibrium condensation theory of a gas having the elemental abundances in the solar system is briefly reviewed. The composition of solids predicted by the equilibrium condensation theory is compared with that of the ice and grains in the nucleus; the

Tetsuo Yamamoto

1987-01-01

194

Brassica carinata protein isolates: chemical composition, protein characterization and improvement of functional properties by protein hydrolysis  

Microsoft Academic Search

Brassica carinata defatted flour has been used to prepare protein isolates by alkaline extraction and precipitation at low pH. Different extraction parameters have been tested, and the chemical composition and functional properties of the resulting isolates have been analyzed. All the isolates had a protein content above 90% and a well balanced amino acid composition according to FAO standards except

J Pedroche; M. M Yust; H Lqari; J Girón-Calle; M Alaiz; J Vioque; F Millán

2004-01-01

195

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

Microsoft Academic Search

As the waste industry continues to move from a disposal-based system to one based on a combination of recovery options, the need for information on the composition of waste increases and this is reflected by the amount of information on the physical composition of municipal solid wastes that is now available. However, there is far less information on the chemical

S. J. Burnley

2007-01-01

196

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

PubMed

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

Herrmann, K

1981-01-01

197

Effect of chemical composition on the properties of burnished Cr18Ni9 steel  

Microsoft Academic Search

1.The deviation of the mechanical properties of burnished Cr18Ni9 steel from the specifications is due to the variation of the chemical composition within the limits prescribed by GOST 5632-61.2.The following chemical composition -0.09-0.11%C, 17–18% Cr, 8–9% Ni, up to 0.30% Ti—is recommended to obtain the required properties of Cr18Ni9 ribbons and sheets. This composition is within the limits prescribed by

N. P. Zhetvin; I. V. Gorbatenko; E. M. Kontsevaya

1963-01-01

198

Characterization of biomass burning particles: chemical composition and processing  

NASA Astrophysics Data System (ADS)

During the Intercontinental Transport and Chemical Transformation (ITCT) mission in April and May of 2002, a forest fire plume was intercepted over Utah on May 19. Gas phase species acetonitrile (CH3CN) (a biomass burning tracer) and carbon monoxide (CO) measured greater than five fold enhancements over background concentrations during this plume crossing. In the 100 sec plume crossing, the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument acquired 202 positive mass spectra of biomass burning particles. Many of these particles contained potassium in addition to organics, carbon, and NO+ (which is a signature for any nitrogen containing compound such as ammonium or nitrate). From characterization of the particle mass spectra obtained during the plume crossing, a qualitative signature has been determined for identifying biomass burning particles. By applying this analysis to the entire ITCT mission, several transport events of smoke plumes have been identified and were confirmed by gas phase measurements. Additional species, such as sulfate, found in the mass spectra of the transported particles indicated processing or aging of the biomass burning particles that had taken place. The analysis has been extended to other field missions (Crystal-Face, ACCENT, and WAM) to identify biomass burning particles without the added benefit of gas phase measurements.

Hudson, P. K.; Murphy, D. M.; Cziczo, D. J.; Thomson, D. S.; Degouw, J.; Warneke, C.

2003-12-01

199

Fine particulate chemical composition and light extinction at Meadview, AZ  

SciTech Connect

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

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

2006-12-15

200

Brazilian Red Propolis--Chemical Composition and Botanical Origin  

PubMed Central

Propolis contains resinous substances collected by honey bees from various plant sources and has been used as a traditional folk medicine since ca 300 BC. Nowadays, the use of evidence-based complementary and alternative medicine (CAM) is increasing rapidly and so is the use of propolis in order to treat or support the treatment of various diseases. Much attention has been focused on propolis from Populus sp. (Salicaceae) and Baccharis dracunculifolia (Asteracea), but scientific information about the numerous other types of propolis is still sparse. We gathered six samples of red propolis in five states of Northeastern Brazil. The beehives were located near woody perennial shrubs along the sea and river shores. The bees were observed to collect red resinous exudates on Dalbergia ecastophyllum (L) Taub. (Leguminosae) to make propolis. The flavonoids of propolis and red resinous exudates were investigated using reversed-phase high-performance liquid chromatography and reversed-phase high-performance thin-layer chromatography. We conclude that the botanical origin of the reddish propolis is D. ecastophyllum. In areas where this source (D. ecastophyllum) was scarce or missing, bees were collecting resinous material from other plants. Propolis, which contained the chemical constituents from the main botanical origin, showed higher antimicrobial activity.

Daugsch, Andreas; Moraes, Cleber S.; Fort, Patricia

2008-01-01

201

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

202

Chemical composition and vasodilatation induced by Cuphea carthagenensis preparations.  

PubMed

The aerial parts of Cuphea carthagenensis (Jacq.) J.F. Macbride (Lythraceae) are traditionally employed in Brazil to treat cardiovascular diseases. The aim of this study was to compare preparations of C. carthagenensis aerial parts (aqueous and ethanol extracts, together with derived fractions) with regard to their total phenolic contents and in vitro vasodilating activity. The main flavonoids found in the extracts were isolated and identified as quercetin derivatives. The extracts and fractions showed similar HPLC profiles with the presence of quercetin-5-O-?-glucopyranoside, quercetin-3-O-?-arabinofuranoside and quercetin-3-sulfate in all of them, but marked differences in the contents of flavonoids, proanthocyanidins, tannis and total phenolics. Excepting the aqueous extract, all assayed preparations elicited vasodilatation on pre-contracted rat aortic rings in the range of pIC(50) 4.53±0.03 to 4.98±0.06. Polynomial regression analysis demonstrated the relationship between vasodilating activity and the contents of flavonoids (r(2)=0.5190), proanthocyanidins (r(2)=0.8016), tannins (r(2)=0.8041) and total phenolics (r(2)=0.6226), suggesting the participation of these compounds in the pharmacological effect and their potential use as chemical markers for the species. PMID:22739415

Krepsky, Patricia Baier; Isidório, Raquel Geralda; de Souza Filho, José Dias; Côrtes, Steyner França; Braga, Fernão Castro

2012-06-26

203

Chemical microsensors  

DOEpatents

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

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

1995-01-01

204

Chemical Bonds  

NSDL National Science Digital Library

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

Consortium, The C.

2011-12-11

205

An Assessment of the Chemical Composition of Rain and Surface Water Samples Collected at Deep Creek Lake, Garrett County, Maryland.  

National Technical Information Service (NTIS)

This report presents the results of chemical analyses performed on rain and surface water samples collected at Deep Creek Lake, Maryland. Acidity and chemical composition of precipitation and surface waters were monitored to determine if acid rain and aci...

H. Scott S. Campbell M. Guiliano

1982-01-01

206

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

PubMed

Eleven samples of dromedary camel colostrum in Kazakhstan, which originated from one farm only, were collected to study the changes in the physico-chemical composition (total fat, total protein, iodine index, lactose, calcium, phosphorus, iron, vitamin C, urea, ammonia, density, Dornic acidity, pH, and skimmed dry matter) all along the first postpartum week. At that time, the fat matter decreased from 25.9% to 3.1% and protein from 17.2% to 4.2%, in contrast to vitamin C which increased. Minerals showed high variations with lower values the first day after parturition and variable changes up to the end of the week where the values were stabilized. The iron concentration decreased from the second day postpartum. No clear changes of the other parameters were observed, notably for the non-protein nitrogen (urea and ammonia). PMID:19763867

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

2009-09-08

207

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

208

Chemical Composition of the RS CVn-type Star Lambda Andromedae  

Microsoft Academic Search

Photospheric parameters and chemical composition are determined for the single-lined chromospherically active RS CVn-type star lambda And (HD 222107). From the high resolution spectra obtained on the Nordic Optical Telescope, abundances of 22 chemical elements and isotopes, including such key elements as 12C, 13C, N and O, were investigated. The differential line analysis with the MARCS model atmospheres gives T

G. Tautvaiÿsienúe; G. Barisevicius; S. Berdyugina; Y. Chorniy; I. Ilyin

2010-01-01

209

Chemotaxonomy of some Paleozoic vascular plants. Part I: Chemical compositions and preliminary cluster analyses  

Microsoft Academic Search

The chemical compositions of plant fossils having trimerophyte (Pertica,Psilophyton princeps, P. cf.jorbesii), rhyniophyte (Taeniocrada), and zosterophyll (Sawdonia) morphological characteristics are chemically analyzed and chemotaxonomically related to vascular ( ?Eohostimella, Renalia, Chahuria) and putative non-vascular plant fossils (Botryococcus, Parka, Pachytheca, Prototaxites,Nematothallus, Spongiophyton, Protosalvinia, Orestovia) whose taxonomic affinities are unknown or speculative. Separation of the material examined into clusters representing higher\\u000a taxa

Karl J. Niklas; Patricia G. Gensel

1976-01-01

210

CHEMICAL COMPOSITION OF OIL SHALE II. DEPENDENCE ON THE EXTRACTION PROCESS  

Microsoft Academic Search

Eastern and Western U.S. and Australian oil shales were retorted in a fixed-bed, bench-scale retorter, using nitrogen and carbon dioxide as sweep gases. The resulting shale oils were chemically characterized by GC\\/MS techniques. Shale oils extracted by nitrogen and carbon dioxide retorting processes were found to have different chemical compositions, even when applied to the same oil shale samples. The

Sunggyu Lee; Mark E. Polasky; Kathy L. Fullerton

1991-01-01

211

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

Microsoft Academic Search

Shale oils obtained by nitrogen retorting of North Carolina, Cleveland, Ohio, Colorado, Rundle, Stuart, and Condor oil shales have been chemically characterized by g.c.-m.s. techniques. After species identification, chemical compositions of the shale oils have been related to the geological origins of the parent shales. Based on the characteristics observed in the chromatograms, eight semi-quantitative parameters have been used to

Mark E. Polasky; Sunil Kesavan; Sunggyu Lee

1991-01-01

212

Liquefaction and product identification of main chemical compositions of wood in phenol  

Microsoft Academic Search

To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using\\u000a phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulose and lignin, were measured\\u000a and extracted according to GB methods. With Fourier transform infrared (FTIR), the product identification of reactant before\\u000a and after liquefaction in phenol was investigated.

Qiu-hui Zhang; Guang-jie Zhao; Shu-jun Jie

2005-01-01

213

Nucleosynthesis in Supernova Outbursts and the Chemical Composition of the Envelopes of Neutron Stars (In Russian)  

Microsoft Academic Search

The formation of chemical elements in the envelopes of neutron stars is considered at the densities varrho=107 to 1013 g cm-3. It is shown, that the compression of cold and hot matter leads to different chemical compositions. The compression of cold matter is accompanied by a decrease of atomic weightA, up to varrho≈3×1012 g cm-3. One may distinguish the following

G. S. Bisnovatyi-Kogan; V. M. Chechetkin

1974-01-01

214

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

Microsoft Academic Search

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

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

1999-01-01

215

Chemical reaction of SiCp\\/Al composites during multiple remelting  

Microsoft Academic Search

In the present study, the chemical reaction of SiCp\\/Al composites during multiple remelting above the liquidus was investigated using Differential Scanning Calorimetry and Transmission Electron Microscope. The experimental results indicated that the chemical reaction of SiC particles increased with increasing remelting temperature and the number of recycling runs. After reaching a certain degree of reaction, no further change occurred during

Tongxiang Fan; Di Zhang; Guang Yang; Toshiya Shibayanagi; Masaaki Naka; Takao Sakata; Hirotaro Mori

2003-01-01

216

Histopathology of Human Coronary Atherosclerosis by Quantifying Its Chemical Composition With Raman Spectroscopy  

Microsoft Academic Search

Background—Lesion composition, rather than size or volume, determines whether an atherosclerotic plaque will progress, regress, or rupture, but current techniques cannot provide precise quantitative information about lesion composition. We have developed a technique to assess the pathological state of human coronary artery samples by quantifying their chemical composition with near-infrared Raman spectroscopy. Methods and Results—Coronary artery samples (n5165) obtained from

Tjeerd J. Romer; James F. Brennan III; Maryann Fitzmaurice; Michael L. Feldstein; Geurt Deinum; Jonathan L. Myles; John R. Kramer; Robert S. Lees; Michael S. Feld

217

Chemical agents and chemical terrorism.  

PubMed

Chemical terrorism is a new threat to the security of mankind, which scale essentially exceeds the impact of use of the most modem firearms. At present time all over the world threats from different radical elements to use radioactive materials, potent poisonous substances and pathogenic microorganisms for terrorist purposes became more frequent. High-toxic chemical substances can fall in terrorist hands through wide range of sources. Potentially misused types of chemical compounds are discussed in this article. PMID:15141987

Patocka, J; Fusek, J

2004-03-01

218

Studies on the Chemical Composition of Bovine Blood  

Microsoft Academic Search

With the development of methods for the analysis of blood, a valuable tool has been placed in the hands of experimenters in physiology and nutrition and of physicians in the clinical labora- tory. At the present time a great deal of information is available on the abnormal composition of hHman blood in disease. A knowledge of the composition of normal

Arthur K. Anderson; Howard E. Gayley; Avery D. Pratt

1930-01-01

219

Isolation, purification and chemical composition of maize root cap slime  

Microsoft Academic Search

Summary The total root exudate isolated axenically from roots is shown to constitute an extremely heterogenous population of particulate and soluble material. Differences in protein and total sugars contents, and neutral sugar composition throughout stages of total root exudate purification are reported. The importance of controlled collection and purification conditions to ensure valid analysis and composition of purified maize root

Annie Chaboud

1983-01-01

220

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

221

Chemical spectroscopy  

Microsoft Academic Search

The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of

J. Eckert; T. O. Brun; A. J. Dianoux; J. Howard; J. J. Rush; J. W. White

1984-01-01

222

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

223

Chemical Name  

Cancer.gov

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

224

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

225

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

226

Elemental Composition and Chemical Classification of Sutter's Mill Chondrites  

NASA Astrophysics Data System (ADS)

The elemental composition of the SM2 fragment of Sutter's Mill is consistent with a CM chondrite. Based on the content of thermally labile elements, our fragment of SM2 did not experience heating over ~500°C.

Friedrich, J. M.; Ebel, D. S.; Jenniskens, P.

2012-09-01

227

Variations in chemical composition and structure of macromolecular components in different morphological regions and maturity stages of Arundo donax  

Microsoft Academic Search

Arundo donax plants were manually separated into fractions of different morphological regions (internodes, nodes and foliage) at different stages of maturity and submitted to chemical composition studies. General chemical composition was determined by established methods. The polysaccharides were fractionated by successive extractions of holocellulose with aqueous KOH solutions. The sugar composition was determined by hydrolysis of polysaccharides followed by GC

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

1997-01-01

228

Composite Chemical Sensors Based on Carbon-Filled Patterned Negative Resists  

NASA Astrophysics Data System (ADS)

Conductometric chemical sensors based on polymer composite films, synthesized by adding conductive fillers to the polymer solutions and deposited between two predefined electrodes, are well established. Deposition of the sensitive composites is usually applied to sensor devices by solvent casting methods such as spin coating, spray coating and drop casting. These methods lack in pattern precision and repeatability. In order to overcome pertinent problems the application of conventional patterning methods for the fabrication of the conductive sensing array is proposed. In this work, we present the deposition of two conductive polymer composites poly(dimethylsiloxane)/carbon black and epoxy polymer/carbon black on the same substrate. Each polymer composite is deposited onto two respective electrodes, effectively creating a conductive polymer chemical sensor pair. The two sensors performance is evaluated and considered as a first step towards the fabrication of a conductometric polymer composite array. Electrical vs dimensional sensitivity issues and the significance of electrode configuration are considered.

Chatzandroulis, Stavros; Andreadis, Nikolaos; Goustouridis, Dimitrios; Quercia, Luigi; Raptis, Ioannis; Beltsios, Konstantinos

2007-09-01

229

The chemical composition and biological properties of coconut (Cocos nucifera L.) water.  

PubMed

Coconut water (coconut liquid endosperm), with its many applications, is one of the world's most versatile natural product. This refreshing beverage is consumed worldwide as it is nutritious and beneficial for health. There is increasing scientific evidence that supports the role of coconut water in health and medicinal applications. Coconut water is traditionally used as a growth supplement in plant tissue culture/micropropagation. The wide applications of coconut water can be justified by its unique chemical composition of sugars, vitamins, minerals, amino acids and phytohormones. This review attempts to summarise and evaluate the chemical composition and biological properties of coconut water. PMID:20032881

Yong, Jean W H; Ge, Liya; Ng, Yan Fei; Tan, Swee Ngin

2009-12-09

230

The Chondrite Neagari: Petrography, Mineralogy, Chemical Compositions, and Cosmogenic Nuclides  

NASA Astrophysics Data System (ADS)

The Neagari meteorite fell on Feb. 18, 1995 at Neagari-machi, Nomi-gun, Ishikawa-ken, Japan (geographical coordinate: 36 degrees 26.9'N, 136 degrees 27.9'E). It was broken into several pieces when it hit a car upon falling. The largest piece weighing about 325 g and a small piece weighing 39 g were brought to the Kanazawa University for the measurements of gamma-rays emitted by cosmogenic nuclides only 2.7 days after the fall. Thereafter, the measurement was repeated several times. Other small pieces were used for petrographic, mineralogical and chemical studies. Noble gas mass spectrometry and AMS were also conducted. The Neagari meteorite shows a distinct, recrystallized structure under the microscopic observation of the thin section. Chondrules, 0.6 to 1.0 mm in diameter, are all present as relicts, buried in the well-recrystallized matrix. The chondrule-matrix boundaries are scarcely discernible in the granulated matrix. Olivine (Fa: 25.3 +/- 0.6 mole%) and orthopyroxene (Fs: 20.6 +/- 0.6 mole%) are the most abundant minerals both in matrix and in the chondrule relicts. Diopside is present as individual grains in the granular matrix. Interstitial feldspar crystal (Or(sub)6.3Ab (sub)88.0 An(sub)5.8) are common in the matrix and chondrule relicts, and often enclose minute pyroxene grains. Main opaque minerals are kamacite, taenite, troilite and chromite, and the metal phase is more abundant than the sulfide phase in the section. Both Fa and Fs values indicate that the Neagari meteorite is an L chondrite. The well-crystallized structure of the matrix, poorly defined outline of relict chondrules in the matrix, the prevalence of clear and well-developed plagioclase grains in the matrix and chondrule relicts and the absence of glass and monoclinic low-Ca pyroxene indicate the petrologic type to be 6. By the non-destructive gamma-ray measurement of the meteorite, eleven cosmogenic nuclides (^44mSc, ^52Mn, ^48V, ^51Cr, ^7Be, ^56Co, ^46Sc, ^57Co, ^54Mn, ^22Na, and ^26Al) have been identified and their contents were determined by using a mock sample having known amounts of natural radioactivities. Among these nuclides, ^44mSc has the shortest half life (2.44 d) and has also been measured in the Mihonoseki meteorite [1]. Cosmogenic components were also observed for ^3He, ^21Ne, and ^38Ar by noble gas mass spectrometry. Cosmic-ray exposure ages calculated from cosmogenic ^21Ne and ^38Ar contents coupled with production rates by Eugster [2] and Schultz et al. [3], respectively, seem to be consistent (about 45 Ma), but the age from ^3He is significantly lower. Considering the loss of radiogenic ^4He, the Neagari meteorite must have experienced a high temperature event in space. Cosmogenic radionuclides ^10Be, ^26Al, and ^36Cl were also measured in an aliquot (77 mg) of the Neagari meteorite using an AMS facility at Lawrence Livermore National Laboratory. The concentrations of these nuclides in conjunction with the noble gas data as well as data of elemental abundances provide better knowledge of the exposure history of this meteorite. References: [1] Shima M. et al. (1993) LPS XXIV, 1297-1298. [2] Eugster O. (1988) GCA, 52, 1649-1662. [3] Schultz L. et al. (1991) GCA, 55, 59-66.

Okada, A.; Komura, K.; Nagao, K.; Nishiizumi, K.; Miyamoto, Y.; Sakamoto, K.; Ebihara, M.; Shima, M.

1995-09-01

231

Chemical composition and antioxidant capacity of free volatile aglycones from basil ( Ocimum basilicum L.) compared with its essential oil  

Microsoft Academic Search

The present paper examines the chemical composition and antioxidant capacity of free volatile aglycones from basil compared to their essential oil. The comparison of chemical composition of volatile aglycones with the chemical composition of essential oil reveals four common compounds: eugenol, chavicol, linalool and ?-terpineol. For the evaluation of the mentioned antioxidant capacities, two different methods were performed: the 2,2?-diphenyl-1-picrylhydrazyl

O. Politeo; M. Jukic; M. Milos

2007-01-01

232

A universal bias in inorganic rainwater chemical composition data  

NASA Astrophysics Data System (ADS)

In the late 1970s, it was recognised that organic acids contributed to the acidity and ionic content of rainwater, but that these acids had not been detected because they were consumed biologically in the period between rainwater collection and subsequent laboratory analysis. Discussion of consequences for measured rainwater composition has been limited to assessment of pH gain that attends organic acid loss. We show that biological effects on rainwater ionic composition are not restricted to pH alone. Ammonium, potassium, nitrate, sulfate, methanesulfonate, and phosphate ions are also removed biologically, but remain in the rainwater in biomass, implying that most previous rainwater composition studies based on ionic analyses will have systematically underestimated nutrient deposition.

Ayers, Gregory P.; Gillett, Robert W.; Selleck, Paul W.

2003-07-01

233

Chemical composition and nutritional quality of Cleome dolichostyla seeds  

Microsoft Academic Search

Seeds ofCleome dolichostyla were analysed for proximate composition, mineral element contents and amino acid composition, in-vitro protein digestibility (IVPD) and calculated protein efficiency ratio (C-PER). The seeds (dry basis) were rich in oil (32.1%), protein (24.6%) and fiber (17.8%) content. The contents of various mineral elements mg\\/100 g) were: Ca=1970, P=493, Mg=127, Na=35, K=465, Fe=71.97, Zn=2.25, Cu=0.44 and Mn=1.45. Aspartic

Wajih N. Sawaya; Jehangir K. Khalil; Saboor Ahmad

1985-01-01

234

Guest Chemical Composition as a Significant Parameter for Hydrate Interpretation  

Microsoft Academic Search

Each guest in compound hydrate has both independent and co-dependent links to formation and dissociation processes. At the simplest level, compound hydrate can be modeled as a single entity that grows at a fixed composition, for example, the case where an infinite reservoir of gas is exposed to a limited quantity of water. In real systems, the rate at which

J. P. Osegovic; M. D. Max

2007-01-01

235

CHEMICAL COMPOSITION OF THE WALLS OF CERTAIN ALGAE  

Microsoft Academic Search

In spite of the fact that numerous investigations of the nature of cell walls of algae have been made, the recorded data are still far too incomplete to be of the greatest service to science. It is usually impossible to obtain from the literature a complete record of the composition of the walls of the most commonly occurring fresh water

MARY E. WURDACK

236

Chemical composition of camel skim milk concentrated by ultrafiltration  

Microsoft Academic Search

Camel skim milk was concentrated by ultrafiltration (UF) to volume concentration ratios (VCR) of 2, 3, 4 and 5. Gross composition and mineral contents of skim milk and retentates, as well as retention and recovery of components were studied. All fat, CN, WPN, 13–18% of NPN and about 1% of lactose were retained during UF of camel skim milk. Recovery

Mohamed A. Mehaia

1996-01-01

237

Chemical composition of antarctic zooplankton during austral fall and winter  

Microsoft Academic Search

Water level, ash content, proximate (protein, lipid, carbohydrate and chitin) and elemental (carbon and nitrogen) composition were analyzed in twentythree species of Antarctic Zooplankton collected during the austral fall (1986) and winter (1988) from the Scotia\\/Weddell Sea region. Extremes in water level, ash content and organic components were typified by copepods and gelatinous forms. Ostracods and polychaetes were generally similar

J. Donnelly; J. J. Torres; T. L. Hopkins; T. M. Lancraft

1994-01-01

238

To measure the chemical composition of a Near Earth Object  

Microsoft Academic Search

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

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

2006-01-01

239

The chemical composition of the RV Tauri variable IW Carinae  

NASA Astrophysics Data System (ADS)

Analysis of the RV Tauri star IW Carinae shows a photospheric composition unlike that reported previously for a few other RV Tau stars but resembling that of certain post-asymptotic giant branch stars (post-AGB) stars. IW Car is carbon-rich: several lines of C I are detected and suggest C/O greater than or = 1. The star is generally metal poor. The composition of (Fe/H) approximately -1.0, (Ca/H) approximately = -1.9 but (Zn/H) approximately 0.0 reflects that of gas of solar metallicity from which easily condensable elements have condensed into dust grains and been removed from the star's photosphere. Separation of gas and dust may have occurred in the present or recent stellar wind of IW Car. These characteristics also suggest that RV Tauri stars are post-AGB objects.

Giridhar, Sunetra; Rao, N. Kameswara; Lambert, David L.

1994-12-01

240

Chemical resistant lead-free glass frit compositions  

SciTech Connect

Glass frit compositions for use in glazes or enamels have a fiber softening point of 535/sup 0/ C. or more and are free of cadmium, lead and arsenic and consist essentially of Bi/sub 2/O/sub 3/-B/sub 2/O/sub 3/-SiO/sub 2/ with R/sub 3/O being 2-8% and RO being 0-9% by weight.

Francel, T.

1985-11-19

241

Chemical Composition of the Leaf Oil of Plectranthus neochilus Schltr  

Microsoft Academic Search

The composition of the essential oil of the leaves of Plectranthus neochilus was analyzed by GC and GC\\/MS. The oil of P. neochilus predominantly comprised monoterpenoids (77.5%) of which citronellol (29.0%), citronellyl formate (11.0%), linalool (9.8%) and isomethone (9.2%) were the major constituents. Furthermore, citronellyl propionate (3.4%) was the main sesquiterpene identified in the oil

O. A. Lawal; A. H. Hutchings; O. Oyedeji

2010-01-01

242

Chemical composition of the essential oil of Feronia elephantum Correa  

Microsoft Academic Search

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

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

2010-01-01

243

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

244

Studies on the chemical composition of kohl stone by X-ray diffractometer.  

PubMed

Use of Kohl (Surma) creates toxicity or protects eye, is one of the most controversial topic of modern medicines. However, modern researches show that kohl forms a thin film on the eye lens thus avoiding the direct contract of harmful UV radiation and glare of sun with lens. Black and shining particles of galena in kohl shield the eyes from glare and reflection of sun and thus protect them from harmful effect of UV radiation emerging from the sun. Based on these findings and other properties of kohl, it was decided to undertake this study to ascertain it's chemical composition and to correlate these properties scientifically. In the present study, kohl stone obtained from Madina (Saudi Arabia) was analyzed to ascertain it's chemical composition. The chemical analysis and X-ray diffractometer results obtained, showed that the main component of kohl stone is galena (PbS). PMID:20067866

Ullah, Pervaiz Habib; Mahmood, Zafar Alam; Sualeh, Mohammad; Zoha, S M S

2010-01-01

245

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

246

Chemical Agents  

Center for Drug Evaluation (CDER)

... FDA has cleared for use by the US military a liquid decontamination lotion intended to remove or neutralize chemical warfare agents and T-2 fungal ... More results from www.fda.gov/drugs/emergencypreparedness/bioterrorismanddrugpreparedness

247

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

248

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

249

Chemical Emergency  

MedlinePLUS

... Prepare Your Workplace Types of Emergency Chemical Emergency Drought Preparedness Earthquake Home Fire Flood Flu Food Safety ... you have been advised by medical professionals. Next Drought Preparedness & Water Conservation Be Red Cross Ready Are ...

250

Synthesis and characterization of SiC-reinforced silicon composites produced by chemical vapor deposition  

SciTech Connect

The goal of this study was to prepare SiC-reinforced silicon matrix composites. Chemical vapor deposition techniques were employed to deposit Si onto the surface of SiC fibers and to infiltrate silicon carbide fibers to form a cylindrical composite. A mixture of SiCl{sub 4} and H{sub 2} was reacted at 1,000{degree}C to produce the Si coating. The morphology of Si deposition was monitored by scanning electron microscopy. The structural properties of the composite were studied by powder x-ray diffraction methods. Surface studies of the composites were investigated with x-ray photoelectron spectroscopy.

Hwan, L.; Willis, W.S.; Suib, S.L. (Univ. of Connecticut, Storrs (USA)); Galasso, F. (United Technologies Research Center, Hartford, CT (USA))

1988-11-01

251

Chemical composition of certain tribal pulses in South India.  

PubMed

Raw seeds of tribal pulses Atylosia scarabaeoides, Canavalia gladiata, Lablab purpureus var. lignosus, Neonotonia wightii var. coimbatorensis, Rhynchosia filipes, Vigna trilobata and Vigna unguiculata subsp. unguiculata were investigated for their proximate composition, minerals, vitamins (niacin and ascorbic acid) and certain anti-nutritional substances. The seeds of L. purpureus var. lignosus and V. trilobata had a higher content of crude protein than the commonly consumed Indian pulses. The seeds were found to be a rich source of minerals like potassium when compared with recommended dietary allowance values. The total free phenolics, tannins, 3,4-dihydroxyphenylalanine and hydrogen cyanide were also analysed. PMID:12775370

Arinathan, V; Mohan, V R; John De Britto, A

2003-05-01

252

Chemical Kinetics  

Microsoft Academic Search

\\u000a While thermodynamics provides steady-state information of the combustion process, chemical kinetics describes the transient\\u000a states of the system during the combustion process. Particularly important is information related to the rate at which species\\u000a are consumed and produced, and the rate at which the heat is released. Combustion chemistry has two important characteristics\\u000a not commonly observed in other chemical systems. First,

Sara McAllister; Jyh-Yuan Chen; A. Carlos Fernandez-Pello

253

The composition of 433 Eros: A mineralogical-chemical synthesis  

NASA Astrophysics Data System (ADS)

The near-Earth asteroid rendezvous (NEAR) mission carried x-ray/gamma-ray spectrometers and multi-spectral imager/near-infrared spectrometer instrument packages which gave complementary information on the chemistry and mineralogy, respectively, of the target asteroid 433 Eros. Synthesis of these two data sets provides information not available from either alone, including the abundance of non-mafic silicates, metal and sulfide minerals. We have utilized four techniques to synthesize these data sets. Venn diagrams, which examine overlapping features in two data sets, suggest that the best match for 433 Eros is an ordinary chondrite, altered at the surface of the asteroid, or perhaps a primitive achondrite derived from material mineralogically similar to these chondrites. Normalized element distributions preclude FeO-rich pyroxenes and suggest that the x-ray and gamma-ray data can be reconciled with a common silicate mineralogy by inclusion of varying amounts of metal. Normative mineralogy cannot be applied to these data sets owing to uncertainties in oxygen abundance and lack of any constraints on the abundance of sodium. Matrix inversion for simultaneous solution of mineral abundances yields reasonable results for the x-ray-derived bulk composition, but seems to confirm the inconsistency between mineral compositions and orthopyroxene/clinopyroxene ratios. A unique solution does not seem possible in synthesizing these multiple data sets. Future missions including a lander to fully characterize regolith distribution and sample return would resolve the types of problems faced in synthesizing the NEAR data.

McCoy, T. J.; Burbine, T. H.; McFadden, L. A.; Starr, R. D.; Gaffey, M. J.; Nittler, L. R.; Evans, L. G.; Izenberg, N.; Lucey, P.; Trombka, J. I.; Bell, J. F., III; Clark, B. E.; Clark, P. E.; Squyres, S. W.; Chapman, C. R.; Boynton, W. V.; Veverka, J.

2001-12-01

254

Chemical Composition of Ultra-High Energy Cosmic Rays Observed by AGASA  

NASA Astrophysics Data System (ADS)

We have observed ultra-high energy cosmic rays above the Greisen-ZatsepinKuz'min cut-off energy by Akeno Giant Air Shower Array. Their chemical composition is a key discriminator of origin models. In the present work, we estimate the average composition by an analysis of muons in air showers with AIRES+QGSJET simulation. The data matches the prediction for light hadron primaries and no indication has been found for a gamma-ray dominance.

Shinozaki, K.; Chikawa, M.; Fukushima, M.; Hayashida, N.; Honda, K.; Inoue, N.; Kadota, K.; Kakimoto, F.; Kamata, K.; Kawaguchi, S.; Kawakami, S.; Kawasaki, Y.; Kawasumi, N.; Mase, K.; Mizobuchi, S.; Nagano, M.; Ohoka, H.; Osone, S.; Sakaki, N.; Sakurai, N.; Sasaki, M.; Sasano, M.; Shimizu, H. M.; Takeda, M.; Teshima, M.; Torii, R.; Tsushima, I.; Uchihori, Y.; Yamamoto, T.; Yoshida, S.; Yoshii, H.

2003-07-01

255

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

Microsoft Academic Search

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

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

2010-01-01

256

Synthesis of copper\\/chromium oxide composites by a chemical processing method  

Microsoft Academic Search

The aim of this paper is to synthesize a copper\\/chromium oxide composite material. The use of a chemical processing method\\u000a like the Pechini method is the best approach to control the chemistry and the microstructure. Nevertheless, the standard Pechini\\u000a method has to be modified to obtain this specific type of composite. In this work, we have adapted two steps. Firstly

Amélie Veillère; Jean-François Silvain; Joël Douin; Michel Lahaye; Namas Chandra; Jean-Marc Heintz

2011-01-01

257

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

Microsoft Academic Search

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

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

1993-01-01

258

Changes in Chemical Composition of Alxa Bactrian Camel Milk During Lactation  

Microsoft Academic Search

Changes in chemical composition of Alxa bactrian camels reared in Inner Mongolia (China) during lacta- tion were investigated. Colostrum and milk samples from 10 nomadic female camels in their first season of lactation were collected periodically from parturition until 90 d postpartum (PP). The average contents of gross composition were 14.23% protein, 4.44% lactose, 0.27% fat, 0.77% ash, and 20.16%

H. Zhang; J. Yao; D. Zhao; H. Liu; J. Li; M. Guo

2005-01-01

259

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis  

Microsoft Academic Search

Objective:This study was undertaken to validate the first quantitative nuclear magnetic resonance (QMR) instrument designed and built to assess body composition in children from birth to adulthood (up to 50 kg).Design:A total of 50 pigs weighing between 3.0 and 49.1 kg were studied. Each piglet's body composition was assessed by quantitative nuclear magnetic resonance (QMR, EchoMRI-AH small), whole-body chemical carcass

A Andres; A D Mitchell; T M Badger

2010-01-01

260

Chemical characterization of smoke from the production process of wood-plastic composites  

Microsoft Academic Search

The chemical composition of unpleasant smell, emitted from the production process of wood-plastic composites using Manchurian\\u000a ash sawdust (Fraxinus mandschurica Rupr.) and polypropylene powder as the raw material, was investigated. Wood sawdust and polypropylene powder were subjected\\u000a to heat treatment to 290C during 8 min (the conditions were similar to those employed on an industrial scale). The emitted\\u000a compounds were

Shi-fa Wang; Ai-jun Zhang

2007-01-01

261

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

Microsoft Academic Search

Density of silicate melts in the Earth's deep interior is important to understand the material circulations in the mantle. We study the role of chemical composition on melt density based on the ideal-mixing model and the third-order Birch–Murnaghan equation of state (EOS). Using this EOS, the role of composition can be understood through its effect on three EOS parameters: room-pressure

Zhicheng Jing; Shun-ichiro Karato

2009-01-01

262

Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites: A Review  

Microsoft Academic Search

Studies on the use of natural fibers as replacement to man-made fiber in fiber-reinforced composites have increased and opened\\u000a up further industrial possibilities. Natural fibers have the advantages of low density, low cost, and biodegradability. However,\\u000a the main disadvantages of natural fibers in composites are the poor compatibility between fiber and matrix and the relative\\u000a high moisture sorption. Therefore, chemical

Xue Li; Lope G. Tabil; Satyanarayan Panigrahi

2007-01-01

263

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

Microsoft Academic Search

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

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

2002-01-01

264

Chemical composition, intraspecies variation and seasonal variation in essential oils of Calendula arvensis L  

Microsoft Academic Search

The essential oil composition of Calendula arvensis was established for the first time using GC and GC\\/MS. Eighty-five essential oil components were identified, which accounted for 90.3g\\/100g of essential oil. The oil contained a high concentration of sesquiterpenes, of which ?-cadinene and ?-cadinol were the main components. The chemical composition of 25 Corsican C. arvensis oils was analyzed to determine

Julien Paolini; Toussaint Barboni; Jean-Marie Desjobert; Nassim Djabou; Alain Muselli; Jean Costa

2010-01-01

265

Mineralogy, Microstructure, and Chemical Composition of Goethites in Some Iron Ore Deposits of Orissa, India  

Microsoft Academic Search

The Joda–Barbil region of the Jamda–Koira valley is one of the most important sources of iron ores in India. The mineralogy, texture, and chemical composition of iron ore of the region have been analyzed to understand the presence of different types of goethite and their compositional variation with respect to Fe, Al2O3, SiO2, and P that are essential for upgrading

S. K. Das; B. Das; R. Sakthivel; B. K. Mishra

2010-01-01

266

The chemical composition of 80 pure maple syrup samples produced in North America  

Microsoft Academic Search

A total of 80 pure maple syrup samples received from primary producers in Canada and the United States were analyzed for their chemical composition, pH and oBrix. The major carbohydrates found in maple syrup (sucrose, glucose and fructose) were determined employing anion exchange high performance liquid chromatography (HPLC) with pulsed amperometric detection. The sucrose content was found to range from

Jackie G. Stuckel; Nicholas H. Low

1996-01-01

267

The chemical composition and membrane stability activity of some herbs used in local therapy for anemia  

Microsoft Academic Search

The chemical composition and the membrane stabilizing activity of the decoctions of the dry Hibiscus sabdariffa Linn. (Malvaceae) calyx (Sobo in a Nigerian language), Theobroma cacao Linn. (N.O. Sterculiaceae) root (cocoa) and the dry stalk of white and red cultivars of Sorghum bicolor (L.) Moench (Poaceae) were determined. These herbs are often used locally for the management of anemia. Ash

O. S. Falade; I. O. Otemuyiwa; A. Oladipo; O. O. Oyedapo; B. A. Akinpelu; S. R. A. Adewusi

2005-01-01

268

Plant response to drought stress simulated by ABA application: Changes in chemical composition of cuticular waxes  

Microsoft Academic Search

Plant cuticles form the interface between epidermal plant cells and the atmosphere. The cuticle creates an effective barrier against water loss, bacterial and fungal infection and also protects plant tissue from UV radiation. It is composed of the cutin matrix and embedded soluble lipids also called waxes. Chemical composition of cuticular waxes and physiological properties of cuticles are affected by

Jana Macková; Martina Vašková; Petr Macek; Marie Hronková; Lukas Schreiber; Ji?í Šantr??ek

2010-01-01

269

Chemical and isotopic compositions of the atmospheres of the giant planets (Review)  

Microsoft Academic Search

Data available on the chemical and isotopic compositions of the upper atmospheres of Jupiter, Saturn, Uranus, and Neptune are used to obtain ranges of variations and of the most probable abundance values of a number of elements and isotopic ratios in the atmospheres of these planets. On the basis of a comparison of these values with data on cosmic abundances

V. A. Dorofeeva; S. P. Borunov

1990-01-01

270

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

Microsoft Academic Search

The temporal variations in the chemical and isotopic compositions of urban stormwater under different land uses, and their dependence on physical parameters such as precipitation intensity, stormwater discharge, cumulative stormwater volumes and the size of the drainage area, were investigated in the coastal city of Ashdod, Israel. During 2000\\/2001 and 2001\\/2002, 46 stormwater events were intensively monitored for precipitation distribution

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

2004-01-01

271

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

Microsoft Academic Search

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

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

2003-01-01

272

[The comparative characteristics of chemically and light-hardened composite materials in vitro].  

PubMed

The strength and color stability of various composites of photo- and chemical consolidation is assessed by laboratory methods. The class of a material is the most essential factor affecting the above characteristics. The macrofilled and hybrid materials showed the best adhesive and bending strength. The method of consolidation does not notably affect the studied characteristics. PMID:10067404

Dedkova, L Iu; Poiurovskaia, I Ia; Peshkina, M G; Chechina, G N

1998-01-01

273

Chemical Composition and Antibacterial Activity of Essential Oils of Ten Aromatic Plants against Human Pathogenic Bacteria  

Microsoft Academic Search

The chemical composition and antibacterial activity of essential oils from 10 aromatic plants Matricaria chamommilla, Mentha piperita, M. spicata, Lavandula angustifolia, Ocimum basilicum, Thymus vulgaris, Origanum vulgare, Salvia officinalis, Citrus limon and C. aurantium have been determined. Antibacterial activity of these oils and their components; i.e. linalyl acetate, linalool, limonene, ?- pinene, ?-pinene, 1,8-cineole, camphor, carvacrol, thymol and menthol were

Petar D. Marin

274

Anatomy, Ultrastructure and Chemical Composition of Food Bodies of Hovenia dulcis (Rhamnaceae)  

Microsoft Academic Search

† Background and Aims Food bodies (FBs) are structures that promote mutualism between plants and ants, which help protect them against herbivores. The present study aims to describe the anatomical organization, ultrastructure and chemical composition of the FBs in Hovenia dulcis, which represent the first structures of this type described in Rhamnaceae. † Methods Leaves in various stages of development

RAFAEL A NDRADE; A L AIDE

275

Chemical composition associated with different particle size fractions in municipal, industrial, and agricultural wastewaters  

Microsoft Academic Search

A more detailed characterization of particulate organic matter in wastewater streams is needed to improve solid–liquid separation and biological processes for wastewater treatment. The objective of this paper was to evaluate particle size distributions and the associated chemical composition for municipal, industrial, and agricultural waste streams. Most of the organic matter in these wastewaters was larger than a molecular weight

Cholnatee Sophonsiri; Eberhard Morgenroth

2004-01-01

276

Effect of exchangeable sodium percentage on the growth, yield, and chemical composition of sunflower  

Microsoft Academic Search

The effect of exchangeable sodium percentage (ESP) on the yield and chemical composition of sunflower was studied in a field experiment with five replications. An ESP higher than 16 delayed the germination and decreased the plant height and stem-to-leaves ratio. Emergence of the flower heads was delayed, but maturity was enhanced at high ESP. The grain yield of sunflower was

R. Chhabra; S. B. Singh; I. P. Abrol

1979-01-01

277

Effect of soil sodicity on the growth, yield and chemical composition of groundnut ( Arachis hypogaea Linn.)  

Microsoft Academic Search

Summary A replicated field experiment was conducted to study the effect of exchangeable sodium percentage (ESP) on the yield, chemical composition, protein and oil content and uptake of nutrients by groundnut (Arachis hypogaea Linn.) variety M-13. ESP over 15 delayed germination and emergence of flowers. There was continuous decrease in dry matter yield at 30 and 60 days of growth,

S. B. Singh; I. P. Abrol

1985-01-01

278

Chemical composition and microbiological assays of marine algae Enteromorpha spp. as a potential food source  

Microsoft Academic Search

Enteromorpha spp. is a marine seaweed present almost year round. It often causes unsightly appearance and foul odor from decomposition by micro-organisms. This generates expenses in cleaning beaches. This work determines chemical and microbiological composition, toxicological evaluation of Enteromorpha spp., and recommends its use in human diets and promotion for commercial exploitation, and provides a solution to an ecological problem.

M. Aguilera-Morales; M. Casas-Valdez; S. Carrillo-Dom??nguez; B. González-Acosta; F. Pérez-Gil

2005-01-01

279

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

280

The chemical composition of the peculiar companion to the millisecond pulsar in NGC 6397  

Microsoft Academic Search

We present the chemical composition of the bright companion to the millisecond pulsar J1740-5340 in NGC 6397, based on high resolution spectra. Though the large rotation velocity of the star broadens the lines and complicates the analysis, the derived abundances are found fully compatible with those of normal unperturbed stars in NGC 6397, with the exception of a few elements

E. Sabbi; R. G. Gratton; A. Bragaglia; F. R. Ferraro; A. Possenti; F. Camilo; N. D'Amico

2003-01-01

281

Assimilation of trace elements by the mussel Mytilus edulis : effects of diatom chemical composition  

Microsoft Academic Search

Mussels have been widely used as bioindicators of coastal contamination, and recent reports have demonstrated that metals are accumulated from both the dissolved phase and from ingested food. In the winter and spring of 1995, we examined the influence of the chemical composition of food (protein content, trace element concentrations and ratios in the diatom Thalassiosira pseudomana) on the assimilation

Wang Wen-Xiong; N. S. Fisher

1996-01-01

282

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

Microsoft Academic Search

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

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

1979-01-01

283

Evolution of the standing hay chemical composition in natural and improved Mediterranean pastures3  

Microsoft Academic Search

Summary: A trial with dairy sheep was conducted in North Sardinia (Italy) to determine the availability and chemical composition trends of natural and improved pastures as standing hay. In winter, available and grazed dry matter yield was higher in the improved pasture (sod-seeding of annual ryegrass + subterranean clover), than in the natural fertilized one (dominated by the spontaneous annual

L. Sulas; S. Caredda; C. Porqueddu

284

Effect of Potassium on Yield, Fruit Quality, and Chemical Composition of Greenhouse-Grown Galia Melon  

Microsoft Academic Search

The effect of different potassium (K) rates on yield, fruit quality, and chemical composition of greenhouse-grown melon (Cucumis melo L., cv. Galia) was investigated. The experiment was carried out in a greenhouse similar to that used by farmers in the coastal Mediterranean region of Turkey. Control and three rates of potassium (0, 200, 400, 600 mg L) were applied to

Mehmet Ali Demiral; A. Turgut Köseoglu

2005-01-01

285

Using high-pressure gel permeation chromatography to evaluate the chemical composition of blended asphalts  

Microsoft Academic Search

One recent innovation in the asphalt industry is the production of asphalts from the products of residuum oil super critical extraction (ROSE) systems. The main purpose of this project was to evaluate such blended ROSE asphalts in order to determine the effects of chemical composition on asphalt properties, and to determine if blended asphalts are significantly different from asphalts produced

Garrick

1986-01-01

286

INFLUENCE OF MINERAL FERTILIZATION ON SELECTED PHYSICAL FEATURES AND CHEMICAL COMPOSITION OF ARONIA FRUIT  

Microsoft Academic Search

A b s t r a c t . Aronia melanocarpa (Michx) Elliot, called also black chokeberry, is a species with lower cultivation requirements within the Rosaceae family. The purpose of the study was to assess the influence of foliar fertilization with Mn, 'Alkalin' (N, K and S i) and Mn + 'Alkalin' on physical features and chemical composition of

Katarzyna Skupie?; Ireneusz Ochmian; Józef Grajkowski

287

The effects of chemical gradients and photoresist composition on lithographically generated line edge roughness  

Microsoft Academic Search

Previous work has demonstrated the dependence of photoresist line edge roughness (LER) on the image-log-slope of the aerial image over a wide range of conditions; however, this relationship does not describe the influence of other factors such as photoresist composition or processing conditions on LER. This work introduces the concept of chemical gradients in the photoresist film rather than gradients

Timothy B. Michaelson; Adam R. Pawloski; Alden Acheta; Yukio Nishimura; C. Grant Willson

2005-01-01

288

Comparison of chemical compositions and bioactive compounds of germinated rough rice and brown rice  

Microsoft Academic Search

The aim of the study was to compare changes in the chemical compositions and bioactive compounds of germinated rough rice and germinated brown rice. Ungerminated rice (brown rice) and germinated rice extract powder were also prepared, for comparison purposes. In general, the concentration of crude protein, total free amino acids, ?-tocopherol, ?-oryzanol, thiamine, niacin and pyridoxine, in the germinated rough

Anuchita Moongngarm; Nattawat Saetung

2010-01-01

289

Relation of optical parameters to the chemical and mineralogical composition of lunar rocks  

Microsoft Academic Search

Correlations are made of albedo with iron content and color index with titanium content, and a method is proposed for determining the approximate chemical composition of lunar rocks from their optical characteristics. Correlations with different minerals are plotted, rough approximations are made of their distributions in three areas of the moon, and the approximations for one area are compared with

N. N. Evsiukov

1975-01-01

290

Connection of optical characteristics with the chemical and mineralogical composition of lunar rocks  

Microsoft Academic Search

Correlations are made of albedo with iron content and color index with titanium content, and a method is proposed for determining the approximate chemical composition of lunar rocks from their optical characteristics. Correlations with different minerals are plotted, rough approximations are made of their distributions in three areas of the moon, and the approximations for one area are compared with

N. N. Evsiukov

1974-01-01

291

The study of the chemical compositions of the Ningqiang carbonaceous chondrite matrix and dark rim  

Microsoft Academic Search

The chemical compositions of the Ningqiang carbonaceous chondrite matrix and a dark rim are analyzed with the instrumental neutron activation method. The results indicate that there are more abundant light REE and chalcophile elements in the matrix of Ningqiang than in the whole rock sample of Ningqiang, and it roughly exhibits a similarity of REE model between the Ningqiang and

Hong Fang; Xi-Zhang Feng; Zhi-Fang Chai

1992-01-01

292

The study of the chemical compositions of the Ningqiang carbonaceous chondrite matrix and dark rim  

Microsoft Academic Search

The chemical compositions of the Ningqiang carbonaceous chondrite matrix and a dark rim are analysed with instrumental neutron activation method. The results indicate that there are more abundant light REE and chalcophile elements in the matrix of Ningqiang than in the whole rock sample of Ningqiang, and it roughly exhibits a similarity of REE model between the Ningqiang and Allende

Fang Hong; Xizhang Feng; Zhifang Chai

1992-01-01

293

Effect of Chemical treatment on Flexure Properties of Natural Fiber-reinforced Polyester Composite  

Microsoft Academic Search

This paper focuses on the study of the effect of chemical treatments of fibers by alkalization on the flexural properties of polyester matrix composite reinforced with natural fibers. The used reinforcement consists of Alfa fiber, extracted from the plant Stippa tenacissima from Hodna Region (Algeria). Alfa fibers are subjected to alkali treatments with NaOH at 1, 5 and 10% for

Mansour Rokbi; Hocine Osmani; Abdellatif Imad; Noureddine Benseddiq

2011-01-01

294

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

295

Comparison of the Chemical Composition and Nutritional Value of Amaranthus cruentus Flour and Its Protein Concentrate  

Microsoft Academic Search

Plants constitute an alternative source of proteins in the human diet, with advantages over animal proteins because of their low content of saturated fats and absence of cholesterol. Within the framework of a wider research project on the role of Amaranthus cruentus (Ac) in lipid metabolism, in this work the chemical composition and biological value of the Ac flour and

N. L. ESCUDERO; M. L. de ARELLANO; J. M. LUCO; M. S. GIMÉNEZ; S. I. MUCCIARELLI

2004-01-01

296

Compositional and structural properties of deuterated plasma enhanced chemical vapour deposited silicon-carbon alloys  

Microsoft Academic Search

Hydrogenated and deuterated amorphous silicon carbon films were prepared by plasma enhanced chemical vapour deposition (PECVD) starting from silane and deuterated methane gas mixtures. The gas percentages was varied in order to produce films with different carbon and silicon content. The elemental composition was determined by Rutherford backscattering and elastic recoil detection analysis and the bonding structure by infrared spectroscopy.

L. Calcagno; F. Giorgis; A. Makthari; P. Musumeci; F. Pirri

1999-01-01

297

Chemical Composition of Insoluble Particles in Superimposed Ice on Storoeya, Svalbard (Sweden).  

National Technical Information Service (NTIS)

The chemical composition of the insoluble impurities in a seven meter long ice core of superimposed ice from the Storoeya ice cap is examined. The concentrations of fourteen elements were determined by PIXE (Particle Induced X-ray Emission) and soot photo...

M. E. Hansson H. Hansson S. Jonsson J. Heintzenberg

1993-01-01

298

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...

299

Introducing a traditional dairy product Ke?: Chemical, microbiological, and sensorial properties and fatty acid composition  

Microsoft Academic Search

In this study, it was aimed to determine the chemical, biochemical, microbiological and sensorial characteristics and fatty acid composition of Ke?, traditionally produced in Bolu province in Turkey. The information on production of 'Ke?' was collected from Bolu province in Turkey. Moreover, 20 samples were taken from the local bazaars in different periods in Bolu. These samples were taken to

Hayri Co?kun; T. Ako?lu; M. Fatih; Mustafa Kiralan; Ali Bayrak

2009-01-01

300

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

301

Influence of physiological effort of growth and chemical composition on antler bone mechanical properties  

Microsoft Academic Search

Antler is a good model to study bone biology both because it is accessible and because it grows and is shed every year. Previous studies have shown that chemical composition changes as the antler is grown, implying constraints in mineral availability and the physiological effort made to grow it. This study aimed at examining antler mechanical properties to assess whether

T. Landete-Castillejos; J. D. Currey; J. A. Estevez; E. Gaspar-López; A. Garcia; L. Gallego

2007-01-01

302

Effect of provenance on free amino acid and chemical composition of Scots pine needles  

Microsoft Academic Search

Free amino acid (16 amino acids) and chemical composition (N, P, K, Mg, Ca, S, Fe, Mn, Cu, Zn) of Scots pine (Pinus sylvestris L.) needles were compared between six provenances in three different experimental areas. The main free amino acids in the\\u000a needles were in the sequence of quantity; glutamic acid, glutamine, arginine and ?-aminobutyric acid. There were no

Hannu Raitio; Tytti Sarjala

2000-01-01

303

Period Change Rate and Chemical Composition 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 (AC), V19 in the globular cluster NGC 5466. The study is based on new CCD photometry and echelle spectrograms acquired at minimum light with the HIRES spectrograph on the 10-m Keck-I telescope. Atmospheric parameters and a new mass estimate are presented. EW measurements

J. Nemec; J. K. McCarthy

1998-01-01

304

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

Microsoft Academic Search

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

Jérôme Viers; Bernard Dupré; Jérôme Gaillardet

2009-01-01

305

Chemical composition controls residue decomposition in soils differing in initial pH  

Microsoft Academic Search

Laboratory incubation studies were conducted to determine the dynamics of low-molecular-weight aliphatic carboxylic acids and their anions (LACAs) and respiration in three soils incorporated with five types of plant residues differing in chemical composition. Concentrations of total and individual LACAs in soils decreased sharply with initial 3 days after addition of plant residues, and varied with types of plant residue

J. M. Xu; C. Tang; Z. L. Chen

2006-01-01

306

Forage evaluation, chemical composition, and in vitro digestibility of continuously grazed star grass  

Microsoft Academic Search

This study evaluated the chemical composition and dry matter (DM) digestibility of leaf, stem, and senescent fractions of star grass (Cynodon plectostachyus Pilger) in summer and winter in the south of Brazil. Four 17.6ha pastures grazed by growing steers in continuous grazing were used. The experiment was divided into two periods: (I) summer: February to June, when five cuts were

F. B Moreira; I. N Prado; U Cecato; F. Y Wada; I. Y Mizubuti

2004-01-01

307

Chemical Composition, Morphological Characteristics, and Cell Wall Structure of Malaysian Oil Palm Fibers  

Microsoft Academic Search

This article deals with the determination of chemical composition and the study of morphological and cell wall structure of oil palm fibers. Cellulose is the main constituent in oil palm fibers, and oil palm trunk (OPT) fiber exhibited the highest content of extractives and lignin. Fiber morphological determination also showed that OPT fibers have the highest fiber length, diameter, and

H. P. S. Abdul Khalil; M. Siti Alwani; R. Ridzuan; H. Kamarudin; A. Khairul

2008-01-01

308

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

309

Investigation of the detailed chemical composition of organic aerosol in a South East Asian Rainforest  

Microsoft Academic Search

The formation of secondary organic aerosol (SOA) in tropical regions is a key uncertainty in quantifying the effect of man made emissions on the climate. Large quantities of volatile organic compounds are emitted from natural biogenic sources in the tropics, including isoprene, monoterpenes and sequiterpenes. There are very few studies of the detailed chemical composition of organic aerosols in tropical

Jacqueline Hamilton; Martyn Ward; M. Rami Alfarra; Alastair Lewis; Gordon McFiggans; Niall Robinson

2010-01-01

310

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

Microsoft Academic Search

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

Philippe Colomban; Gwénael Gouadec

2005-01-01

311

Flash Point and Chemical Composition of Aviation Kerosene (Jet A). Revision.  

National Technical Information Service (NTIS)

The relationship between chemical composition, flash point, and ignition energy was examined for eight samples of aviation kerosene (Jet A) with flash points between 29 deg C (84 deg F) and 74 deg C (165 deg F). We report the results of liquid characteriz...

C. D. Nuyt J. E. Shepherd J. E. Woodrow J. J. Lee

2000-01-01

312

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

2013-09-09

313

Multiple regression modelling of mineral base oil biodegradability based on their physical properties and overall chemical composition  

Microsoft Academic Search

A set of 38 mineral base oils was characterized by a number of chemical (i.e., overall chemical composition) and physical parameters used routinely in industry. Their primary biodegradability was evaluated using the CEC L-33-A-93 test. Multiple (stepwise) linear regression (MLR) analyses were performed to describe the relationships between the biodegradability values and the chemical or physical properties of oils. Chemical,

Frédérique Haus; Olivier Boissel; Guy-Alain Junter

2003-01-01

314

The gross chemical composition and fatty acid composition of 18 species of tropical Australian microalgae for possible use in mariculture  

Microsoft Academic Search

The gross chemical composition and fatty acid composition of 18 species of tropical Australian microalgae (2 cryptomonads, 8 diatoms, 3 prasinophytes, 4 prymnesiophytes and a rhodophyte) grown under standard conditions (pH 8.3±0.2, temperature 25±1°C, photon flux density 80±2 ? mol m?2 s?1 and salinity 25±1‰ and harvested in late log phase of growth), were determined as part of a program

Susan M Renaud; Luong-Van Thinh; David L Parry

1999-01-01

315

Stress transfer from polymerization shrinkage of a chemical-cured composite bonded to a pre-cast composite substrate  

Microsoft Academic Search

Objectives: (1) To develop and test a strain gauge-based method for evaluating the strain transferred through a bonded interface to a deformable substrate; and (2) to develop and test a finite element (FE) model for evaluating the stress development in a chemical-cured composite during polymerization.Methods: A generic light-cured resin composite was used to fabricate a rectangular plate with an internal

Ronald L. Sakaguchi; Jack L. Ferracane

1998-01-01

316

Effect of chemical composition on corrosion and wear behaviour of the composite Ni–Fe–Al 2O 3 coatings  

Microsoft Academic Search

The nickel, metallic Ni–Fe and composite Ni–Fe–Al2O3 electrodeposited coatings have been investigated for mean iron content in metallic matrix up to 41wt.%, the mean size of aluminium oxide particles between 0.5 and 5?m, and mean content of Al2O3 particles in range 104–106mm?2. The various properties have been investigated: chemical composition of coatings, adhesion, thickness, hardness, roughness, corrosion properties and wear

R. Starosta; A. Zielinski

2004-01-01

317

Chemical composition of nuts and seeds sold in Korea  

PubMed Central

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

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

2013-01-01

318

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

319

Chemical composition of urban airborne particulate matter in Ulaanbaatar  

NASA Astrophysics Data System (ADS)

Atmospheric pollution caused by airborne particulate matter in the winter season in Ulaanbaatar, Mongolia is a very serious problem. However, there is a complete lack of scientific observation data to define the situation prior to any remediation. PM10 and PM2.5 average monthly values obtained by continuous monitoring showed the concentrations of particles of both size categories exceeded 100 ?g m -3 during November to February (winter). PM10 particles were sampled with filters in January (i.e. during the heating period) and June (i.e.non-heating period) of 2008 in central Ulaanbaatar. To determine the composition of urban airborne particulate matter we analyzed a range of ionic components, multiple elements including heavy metals, and organic and inorganic carbon (soot). We also measured the stable carbon isotope ratio of the soot. Total carbon (sum of organic carbon and inorganic carbon) accounted for 47% of the mass of the PM10 during the heating period and 33% during the non-heating period, and was the largest component of urban airborne particulate matter in Ulaanbaatar. Stable isotope ratios (? 13 C) of soot generated during the heating period (-23.4 ± 0.2‰) approximated the ratios for coal used in Ulaanbaatar (-21.3 to -24.4‰), while the ratios during the non-heating period (-27.1 ± 0.4‰) were clearly different from the coal values. In the heating period, a very high correlation was observed between soot and organic carbon, SO 4 2- , NO 3 - , F - , Zn, As, and Pb, and we concluded that they were derived from coal combustion along with soot. In addition, the concentrations and their ratios relative to each other of Al, Fe, Ca, K, Na, Mg, and Mn hardly differed between the heating period and the non-heating period, and it was concluded that they were derived from soil dust.

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

2011-10-01

320

Chemical Warfare and Chemical Disarmament.  

ERIC Educational Resources Information Center

|Described are some of the technical, military, and political considerations that bear most directly on the choices facing the United States and its NATO allies on modern lethal chemical weapons. (BT)|

Meselson, Matthew; Robinson, Julian Perry

1980-01-01

321

Annual Variation in the Chemical Composition of Sclerosponges  

NASA Astrophysics Data System (ADS)

Sclerosponges secrete hard calcareous skeletons and in the Caribbean typically have a growth rates of between 0.1 to 0.3 mm/yr. In contrast to scleractininan corals where the animal tissue occupies skeletal material which represents 25 per cent of the annual extension, the live tissue of certain species can occupy the upper 1 mm, equivalent to four years of growth. The question therefore arises as to whether intra-annual variations in the chemistry of the skeletons of sclerosponges exist and, if so, are they time averaged as a result of the large thickness of live sponge tissue. In order to address this question we microsampled the skeleton of a sclerosponge obtained from the Tongue of the Ocean in the Bahamas at a resolution every 0.032 mm for carbon and oxygen isotopes and used a laser ICP-MS to measure variations in concentrations of Sr, Mg, Ba, U, and Pb. This sample had been previously dated using U-Th. The age model was refined by comparing trends in the carbon isotopic composition of the skeleton with the C-13 Suess effect and changes in the Pb/Ca ratio to the well known variation of Pb in the atmosphere. Spectral analyses of the oxygen isotopic and Sr/Ca ratio from the specimen revealed a number of significant peaks corresponding to growth rates between 0.11 and 0.44 mm/yr which we interpret as reflecting the presence of a variable growth rate. By counting the number of cycles in the Sr/Ca ratio we can obtain an age which agrees within +/- 1 year of that measured using U/Th. The use of cycle counting offers an alternative dating method to U/Th in situations where age dating to an accuracy of 1 year is required. Questions as to whether the annual cyclicity in the skeleton of the sclerosponge reflects true intra-annual variability will addressed through rigorous calibration experiments currently underway.

Swart, P. K.; Rosenheim, B.; Thorrold, S.; Rubenstone, J.

2001-12-01

322

Chemical composition of Asian continental outflow over the western Pacific: Results from Transport and Chemical Evolution over the Pacific (TRACE-P)  

Microsoft Academic Search

We characterize the chemical composition of Asian continental outflow observed during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission during February–April 2001 in the western Pacific using data collected on the NASA DC-8 aircraft. A significant anthropogenic impact was present in the free troposphere and as far east as 150°E longitude reflecting rapid uplift and transport of

R. S. Russo; R. W. Talbot; J. E. Dibb; E. Scheuer; G. Seid; C. E. Jordan; H. E. Fuelberg; G. W. Sachse; M. A. Avery; S. A. Vay; D. R. Blake; N. J. Blake; E. Atlas; A. Fried; S. T. Sandholm; D. Tan; H. B. Singh; J. Snow; B. G. Heikes

2003-01-01

323

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

Microsoft Academic Search

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

R. O. Guo; P. K. Rohatgi

1998-01-01

324

Determination of the chemical composition distribution of copolymers of styrene and butadiene by gradient polymer elution chromatography  

Microsoft Academic Search

In order to determine the chemical composition distribution (CCD) of styrene-butadiene copolymers, gradient polymer elution chromatography has been performed. The separation is mainly based on differences in solubility among the copolymer molecules with different chemical composition. The solubility of a copolymer is dependent on the following parameters: temperature, type of solvent\\/non-solvent mixture, molecular mass of the polymer and the chemical

P. J. C. H. Cools; F. Maesen; B. Klumperman; A. M. van Herk; A. L. German

1996-01-01

325

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

326

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

327

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 98âDefault Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...

2013-07-01

328

Genetic and environmental effects on chemical composition related to sensory traits in common beans ( Phaseolus vulgaris L.)  

Microsoft Academic Search

The chemical composition determines plant-derived foods’ sensory traits; genetic and environmental effects and their interactions determine chemical composition. Understanding the importance of each factor should help characterise foodstuffs according to the variety and place of cultivation. We studied the effects of variety (five landraces+two checks) and environment (five locations and two years) on some molecules important for beans’ (Phaseolus vulgaris

Alexy Florez; Montserrat Pujolà; Jordi Valero; Enric Centelles; Antoni Almirall; Francesc Casañas

2009-01-01

329

Chemical Composition and Antioxidant Effect of Free Volatile Aglycones from Nutmeg (Myristica fragrans Houtt.) Compared to Its Essential Oil  

Microsoft Academic Search

The paper reports on the isolation of glycosidically bound volatiles from nutmeg, identification of free aglycones, and determination of the antioxidative power of free aglycones in compari- son with nutmeg essential oil. Comparison of the chemical composition of free volatiles with the chemical composition of free volatile compounds found in the essential oil reveals only two common compounds (eugenol, terpinen-4-ol).

Mila Juki; Olivera Politeo; Mladen Milo

330

Chemical erosion of different carbon composites under ITER-relevant plasma conditions  

NASA Astrophysics Data System (ADS)

We have studied the chemical erosion of different carbon composites in Pilot-PSI at ITER-relevant hydrogen plasma fluxes (~1024 m-2 s-1) and low electron temperatures (Te~1 eV). Optical emission spectroscopy on the CH A-X band was used to characterize the chemical sputtering. Fine grain graphite (R 6650, SGL Carbon Group), ITER-reference carbon fiber composite material (SNECMA NB31 and NB41; Dunlop 3D), nano- and micro-crystalline diamond coatings on molybdenum and SiC (Silit® SKD Reaction-Bonded, Saint-Gobain Ceramics) were compared. The chemical sputtering was similar for the different composites under comparable plasma conditions, except for SiC, which produced a ten times lower rate. The CH emission was constant at electron temperatures Te>1 eV and ion fluxes ranging between 1023 and 1024 m- 2 s-1, but decreased at lower temperatures. This decrease is possibly due to changes in the excitation of CH and not due to a change in the chemical erosion rate.

Westerhout, J.; Borodin, D.; Al, R. S.; Brezinsek, S.; 't Hoen, M. H. J.; Kirschner, A.; Lisgo, S.; van der Meiden, H. J.; Philipps, V.; van de Pol, M. J.; Shumack, A. E.; De Temmerman, G.; Vijvers, W. A. J.; Wright, G. M.; Lopes Cardozo, N. J.; Rapp, J.; van Rooij, G. J.

2009-12-01

331

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

2012-11-20

332

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

333

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

334

Corrosion protection of Al alloys and Al-based metal-matrix composites by chemical passivation  

SciTech Connect

Chemical passivation by immersion of aluminium alloys and aluminium 6061/ silicon carbide and aluminium 6061/graphite metal-matrix composites in cerium chloride solution produces very corrosion-resistant surfaces. Aluminium 6061 and aluminium 7075-T6 that had been immersed in 1000 ppm cerium chloride for one week did not suffer from pitting corrosion during immersion in acerated 0.5 N NaCl for three weeks. For aluminium 7075-T7l3 some improvement of the corrosion resistance was also achieved, but to a much lesser extent. Chemical passivation in cerium chloride was also successful for aluminium/silicon carbide and Allgraphite.

Mansfeld, F.; Lin, S.; Sim, S.; Shih, H.

1989-08-01

335

Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign  

NASA Astrophysics Data System (ADS)

Particle hygroscopic growth at RH =90%, cloud condensation nuclei (CCN) activity, and size-resolved chemical composition were concurrently measured in the Thüringer Wald mid-level mountain range in central Germany in fall season of 2010. The median hygroscopicity parameter values, ?, of 50, 75, 100, 150, 200, and 250 nm particles derived from hygroscopicity measurements are respectively 0.14, 0.14, 0.17, 0.21, 0.24, and 0.28 during the sampling period. The closure between HTDMA-measured (?HTDMA) and chemical composition-derived (?chem) hygroscopicity parameters was performed based on the Zdanovskii-Stokes-Robinson (ZSR) mixing rule. Using size-averaged chemical composition, the ? values are substantially overpredicted (30% and 40% for 150 and 100 nm particles). Introducing size-resolved chemical composition substantially improved closure, and the differences between ?HTDMA and ?chem are within 10%. We found that the evaporation of NH4NO3, which may happen in H-TDMA system, could lead to a discrepancy in predicted and measured particle hygroscopic growth. The hygroscopic parameter of the organic fraction, ?org is positively correlated with the O : C ratio (?org =0.19 · (O : C)-0.03). Such correlation is helpful to define the ?org value in the closure study. ? derived from CCN measurement was around 30% (varied with particle diameters) higher than that determined from particle hygroscopic growth measurements (here, hydrophilic mode is considered only). This difference might be explained by the surface tension effects, solution non-ideality, and the partial solubility of constituents or non-dissolved particle matter. However, due to these effects being included in HTDMA-derived ? calculations, we could not distinguish the specific roles of these effects in creating this gap. Therefore, extrapolating from HTDMA data to properties at the point of activation should be done with great care. Finally, closure study between CCNc-measured (?CCN) and chemical composition (?CCN,chem) was performed using CCNc-derived ? values for individual components. The results show that the ?CCN can be well predicted using particle size-resolved chemical composition and the ZSR mixing rule.

Wu, Z. J.; Poulain, L.; Henning, S.; Dieckmann, K.; Birmili, W.; Merkel, M.; van Pinxteren, D.; Spindler, G.; Müller, K.; Stratmann, F.; Herrmann, H.; Wiedensohler, A.

2013-03-01

336

Chemical profiles of switchgrass  

Microsoft Academic Search

Chemical analysis studies were conducted for four populations of switchgrass (Alamo, Kanlow, GA993, and GA992), Panicum virgatum L., which were partitioned into leaves, internodes, and nodes. The variations in carbohydrate compositions, lignin and extractives content, higher heating value (HHV), and the syringyl:guaiacyl ratio of switchgrass were determined. The experimental results indicated that bulk chemical profiles for the four populations of

Zhoujian Hu; Robert Sykes; Mark F. Davis; E. Charles Brummer; Arthur J. Ragauskas

2010-01-01

337

Chemical sensors  

SciTech Connect

This review of chemical sensors contains the following topics of interest: books and reviews; reviews of sensors by their type; fabrication and selectivity; data processing; thermal sensors; mass sensors (fabrication, gas sensors, and liquid sensors); electrochemical sensors (potentiometric sensors, amperometric sensors, and conductometric sensors); and optical sensors (fabrication, liquid sensors, biosensors, and gas sensors). 795 refs., 1 tab.

Janata, J.; Josowicz, M.; DeVaney, D.M. (Pacific Northwest Lab., Richland, WA (United States))

1994-06-15

338

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…

Barry, Dana M.

339

Chemical Ionization  

Microsoft Academic Search

\\u000a Mass spectrometrists have ever been searching for ionization methods softer than EI, because molecular weight determination\\u000a is key for structure elucidation. Chemical ionization (CI) is the first of the so-called soft ionization methods we are going to discuss (cf. Fig. 1.2).

Jürgen H. Gross; Mass Spectrometry

340

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

341

Chemical Indicators.  

ERIC Educational Resources Information Center

|This science sourcebook was written for intermediate grade teachers to provide guidance in teaching a specially developed unit on chemical indicators. Directions and suggestions for guiding student science activities are given. Some of the activities concern soil testing, crystals, and household powders such as sugar and salt. A list of necessary…

Prombain, Dorothy R.; And Others

342

Cloud Condensation Nuclei Activity Associated with Chemical Composition and Precipitation Events  

NASA Astrophysics Data System (ADS)

Measurements of ambient cloud condensation nuclei (CCN) concentrations can be improved by simultaneously collecting information on the activation size of the CCN along with chemical composition of the ambient aerosol. A size scanning CCN instrument developed at Scripps Institution of Oceanography was deployed as part of the Calwater project in the Sierra Nevada foothills of California during February and March of 2010. The instrument was capable of determining the critical diameter of activation for the ambient aerosol during a 20 minute scan. During the study period, the CCN activation size increased after each rain event and the activity slowly returned over the next few days. The critical diameter of the overall aerosol was largest (least active) immediately following precipitation events. The average critical diameter would typically decrease by 20% in the time between major precipitation events. This regeneration of the CCN activity can be partially attributed to the transport of sulfate and nitrate pollution to replace the particles that were washed out by the rain, but it may also be due to chemical changes via aging and oxidation mechanisms. Since CCN activity is determined by the particles size and chemical composition, the changes in critical diameter indicate a change in the chemical composition of the available CCN particles. By comparing the critical diameters with aerosol chemical data from a semi-real time aerosol ion chromatograph, the CCN activity was generally correlated with the mass loading of sulfate and nitrate. Deviations from the expected activity of sulfate and nitrate indicate the existence of other compounds that contribute to activity through additional dissolution and by reducing the surface tension. The contribution to CCN activity from additional compounds, including organic surfactants, can be estimated by observing the deviation of the measured critical diameters from values calculated using only the measured nitrate+sulfate mass fraction.

Corrigan, C.; Roberts, G. C.; Zauscher, M.; Suski, K.; Noblitts, S.; Sullivan, A. P.; Collett, J. L.

2010-12-01

343

Influence of oxygen-inhibited layer on dentin bond strength of chemical-cured resin composite.  

PubMed

This study evaluated the influence of an oxygen-inhibited layer on the surface free energies of three single-step self-etch adhesives and on the bond strength of chemical-cured resin. Adhesives were applied to bovine dentin and light irradiated, and the oxygen-inhibited layer was either retained or removed. Surface free energies were determined by measuring the contact angles of test liquids placed on the cured adhesives. Dentin bond strengths of chemical-cured resin with and without the oxygen-inhibited layer were measured. Ultrastructural observation of the restorative-dentin interface was made by scanning electron microscopy. For all surfaces, values of the estimated surface tension component, Lifshitz-Van der Waals force (?S (LW) ), were relatively constant. Values for the Lewis acid (?S (+) ) component increased slightly when the oxygen-inhibited layer was removed, whereas those of the Lewis base (?S (-) ) component decreased significantly. The bond strength of the chemical-cured resin composite was significantly higher in specimens without an oxygen-inhibited layer (7.6-8.0 MPa) than in those with an oxygen-inhibited layer (4.8-5.2 MPa). Small gaps between adhesive and resin composite were found for the group with an oxygen-inhibited layer. These results indicate that the absence of an oxygen-inhibited layer in single-step self-etch adhesives promotes higher dentin bond strength of the chemical-cured resin. PMID:24028599

Yamaji, Ayumi; Koga, Kensaku; Tsujimoto, Akimasa; Shimizu, Yusuke; Tsubota, Keishi; Takamizawa, Toshiki; Miyazaki, Masashi

2013-08-17

344

Chemical modification of wood  

Treesearch

Source: Handbook of wood chemistry and wood composites. ... deterioration, wood chemistry, chemical reactions, dimensional stability, modified wood ... this page and attach it to the printout of the article, to retain the full citation information .

345

Composited BCN/carbon fibers prepared by hot-filament chemical vapor deposition  

NASA Astrophysics Data System (ADS)

The combined BCN/carbon fibers with porous configuration have been successfully prepared by hot-filament chemical vapor deposition (HF-CVD). The composited materials consist of carbon fiber inside covered by the cylindrical BCN films. The differences in the surface morphology and the diameter of the composite fibers are related to the different reactant gases. It is demonstrated that the elements of B, C, and N are chemically bonded with atomic-level BCN hybrid in the composite fibers. The resistance of the composite fibers is about 300 ? which is 10 times higher than that of the isolated carbon fibers (27.5 ?). When the applying voltage increases up to 8-15 V, the BCN films have been broken down and the resistance of composite fibers decreases to the typical value of the carbon fibers. The composite fibers with porous configuration have the strongly capacity to adsorb oxygen. The findings suggest that the combined BCN/carbon fibers are favorable for achieving high performance nano-optoelectronic and sensor devices.

Lü, Jiannan; Li, Hongdong; Zhu, Pinwen; Lü, Xianyi; Li, Yingai

2011-03-01

346

FY98 Final Report Initial Interfacial Chemical Control for Enhancement of Composite Material Strength  

SciTech Connect

The U.S. Army Armament Research Development and Engineering Center (ARDEC) sponsored this research project to support the development of new self-assembled monolayer fiber coatings. These coatings can greatly increase the bond strength between the fiber and the resin matrix of a composite material. Composite ammunition components molded from such materials will exhibit higher strength than current materials, and will provide a major improvement in the performance of composites in military applications. Use of composite materials in military applications is desirable because of the lighter weight of the materials and their high strengths. The FY97 project investigated initial interfacial chemical control for enhancement of composite material strength. The core of the project was to modify the covalent interface of glass fibers (or other reinforcing fibers) to induce strong, uniform, defect-free adhesion between the fibers' surfaces and the polymer matrix. Installing a self-assembled monolayer tailored to the specific matrix resin accomplished this. Simply, the self-assembled monolayer modifies the fiber to make it appear to have the same chemical composition as the resin matrix. The self-assembled monolayer creates a receptive, hydrophobic interface that the thermoset resin (or polymer precursors) would wet more effectively, leading to a higher contact surface area and more efficient adhesion. The FY97 work phase demonstrated that it is possible to increase the adhesive strength, as well as increase the heat deflection temperature through the use of self-assembled monolayer.

GE Fryxell; KL Alford; KL Simmons; RD Voise; WD Samuels

1999-10-14

347

Chemical composition and moisture-absorption/retention ability of polysaccharides extracted from five algae.  

PubMed

In this study, we prepared seven polysaccharides extracted from five algae including one brown alga Saccharina japonica, one red alga Porphyra haitanensis and three green algae Codium fragile, Enteromorpha linza and Bryopsis plumose. The chemical composition and capability of moisture-absorption and moisture-retention were investigated in comparison with those of hyaluronic acid (HA). The low molecular weight polysaccharides extracted from brown seaweed exhibited the highest moisture-absorption and moisture-retention abilities of all of the polysaccharides studied and performed better than HA. The relationships between chemical composition (including sulfated groups, monosaccharide, and molecular weight) and the functions of polysaccharides were also studied. We found the sulfated group was a main active site for moisture-absorption and moisture-retention abilities. These abilities were also related to molecular weight; with the exception of the low molecular weight polysaccharide extracted from red seaweed, lower molecular weight improved moisture-absorption and moisture-retention abilities. PMID:23500437

Wang, Jing; Jin, Weihua; Hou, Yun; Niu, Xizhen; Zhang, Hong; Zhang, Quanbin

2013-03-13

348

SiC whisker/Si3N4 composites by a chemical mixing process  

SciTech Connect

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

Wang, Hongyu; Fischman, G.S.

1991-10-01

349

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.

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

1980-01-01

350

Chemical composition and antibacterial activity of essential oils from Myrcia alagoensis (Myrtaceae).  

PubMed

The chemical composition and antibacterial activity of essential oils obtained from fresh and dried leaves of Myrcia alagoensis O. Berg, collected in a secondary forest remnant in north-eastern Brazil, was compared. The essential oils were obtained by hydrodistillation from fresh and dried leaves, and analysed by GC/FID and GC/MS. The antimicrobial properties of the oils were investigated against five bacteria by determination of the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The essential oils were rich in cyclic sesquiterpenes, such as germacrene B, with antibiotic action against Gram-positive and Gram-negative bacteria. The drying process after collection interfered with the chemical composition and antibacterial activity of the assessed samples. PMID:23513746

Silva, Aline do N; Uetanabaro, Ana Paula T; Lucchese, Angélica M

2013-02-01

351

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

352

Chemical compositions of four B-type supergiants in the SMC wing  

NASA Astrophysics Data System (ADS)

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

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

2005-01-01

353

Chemical composition of endemic Scorzonera sandrasica and studies on the antimicrobial activity against multiresistant bacteria.  

PubMed

The present study describes the antimicrobial activity and chemical composition of Scorzonera sandrasica Hartvig et Strid (Family Asteraceae), endemic to Turkey. The antimicrobial activity of the hexane, chloroform, ethyl acetate, and ethanol extracts of the aerial parts of S. sandrasica was evaluated against microorganisms, including multiresistant bacteria, using a paper disc diffusion method. The chemical composition of the chloroform extract of the plant was determined by gas chromatography and gas chromatography-mass spectrometry. The major compounds of the chloroform extract of the plant were caryophyllene oxide (19.7%), manoyl oxide (16.5%), and manool (11.3%), respectively. The extracts had antibacterial activity; however, no antifungal activity was observed against the two fungi. In particular, the ethanol and chloroform extracts exhibited significant activity against multiresistant strains of Stenotrophomonas maltophilia. PMID:20438328

Ugur, Aysel; Sarac, Nurdan; Ceylan, Ozgur; Duru, M Emin; Beyatli, Yavuz

2010-06-01

354

[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

355

Neem cake: chemical composition and larvicidal activity on Asian tiger mosquito.  

PubMed

New pesticides based on natural products are urgently needed, in consideration of their environmental care and lower collateral effects. Neem oil, the main product obtained from Azadiractha indica A. Juss, commonly known as neem tree, is mainly used in medical devices, cosmetics and soaps, as well as important insecticide. Manufacturing of neem oil first includes the collection of the neem seeds as raw material used for the extraction. Neem cake is the waste by-product remaining after extraction processes. The quality of the oil, as that of the cake, strictly depends from the quality of seeds as well as from the type of extraction processes used, which strongly influences the chemical composition of the product. Currently, the different types of commercial neem cake on the market are roughly identified as oiled and deoiled cake, but several other differences can be detected. The differences are relevant and must be determined, to obtain the necessary correlation between chemical constitution and larvicidal activities. Six different batches of neem cake, marketed by several Indian and European companies, were analyzed by HPLC and HPTLC, and their fingerprints compared, obtaining information about the different compositions, focusing in particular on nortriterpenes, considered as the main active components of neem oil. Therefore, the chemical composition of each cake was connected with the biological activitiy, i.e., the effects of the extracts of the six neem cakes were tested on eggs and larvae of Aedes albopictus (Stegomyia albopicta) (Diptera: Culicidae), commonly known as Asian tiger mosquito. The results confirmed the previously reported larvicide effects of neem cake that, however, can now be related to the chemical composition, in particular with nortriterpenes, allowing in that way to discriminate between the quality of the various marketed products, as potential domestic insecticides. PMID:22422292

Nicoletti, Marcello; Mariani, Susanna; Maccioni, Oliviero; Coccioletti, Tiziana; Murugan, Kardaray

2012-03-16

356

Chemical composition of xylem sap of tomato grown on bicarbonate containing medium  

Microsoft Academic Search

Incorporation of bicarbonate (HCO3 ) by the roots of tomato seedlings resulted in an increase in biomass production and changed the chemical composition of xylem sap. In the xylem sap of seedlings grown on a medium enriched with HCO3 (5.68 mM dm, series II) compared with the control (series I) the element content increased by about 27% and 33% for

J. Bialczyk; Z. Lechowsk

1995-01-01

357

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

Microsoft Academic Search

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

DEL RIÄO; ANA GUTIE Ä RREZ

358

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

359

Electrical conductivity of chemically modified multiwalled carbon nanotube\\/epoxy composites  

Microsoft Academic Search

The electrical conductivity of oxidized multiwalled carbon nanotubes (MWNT)\\/epoxy composites is investigated with respect to the chemical treatment of the MWNT. The oxidation is carried out by refluxing the as-received MWNT in concentrated HNO3 and H2O2\\/NH4OH solutions, respectively, under several different treatment conditions. The oxidized MWNT are negatively charged and functionalized with carboxylic groups by both solutions. The MWNT oxidized

Yoon Jin Kim; Taek Sun Shin; Hyung Do Choi; Jong Hwa Kwon; Yeon-Choon Chung; Ho Gyu Yoon

2005-01-01

360

Chemically and thermally conjugate synthesis of silicon nitride based compositions using ferrosilicon  

Microsoft Academic Search

The results of synthesis of composite materials based on silicon nitride, which have been discussed from the standpoint of\\u000a chemical and (or) thermal conjugation, are presented. Synthesis of silicon nitride via the interaction of ferrosilicon in\\u000a nitrogen in the combustion regime is examined as the inducing process. It is shown that the energy of self-propagating high-temperature\\u000a synthesis makes it possible

L. N. Chukhlomina

2009-01-01

361

Chemical Composition and Fatty Acid Profile of the Lipid Fractions of Selected Nigerian Indigenous Oilseeds  

Microsoft Academic Search

Seeds of Cucumeropsis edulis, Hevea brasiliensis, Hura crepitans, Jatropha curcas, Khaya ivorensis and Citrus sinensis were evaluated for their proximate composition, chemical properties and fatty acid profiles. The moisture contents of the seeds ranged from 5.3 to 9.0% while the oil content was between 32.5% for Cucumeropsis edulis and 48.3% for Khaya ivorensis. The ash content ranged between 3.6 and

J. A. O. Oyekunle; A. A. Omode

2008-01-01

362

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

Microsoft Academic Search

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

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

363

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

Microsoft Academic Search

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

U. E. Inyang; U. J. Abah

1997-01-01

364

Chemical composition of size-resolved atmospheric aerosols in the eastern Mediterranean during summer and winter  

Microsoft Academic Search

The chemical composition of aerosols has been determined in 30 size-resolved samples collected using a Berner low-pressure impactor during two campaigns conducted at a coastal site in the Eastern Mediterranean in July 2000 and in January 2001. Sulfate (SO42?) and ammonium (NH4+) have been identified as the main ionic components of the sub-micronic aerosol fraction, with SO42? accounting for up

H Bardouki; H Liakakou; C Economou; J Sciare; J Smol??k; V Žd??mal; K Eleftheriadis; M Lazaridis; C Dye; N Mihalopoulos

2003-01-01

365

Changes in chemical composition, physical properties and microstructure of duck egg as influenced by salting  

Microsoft Academic Search

Changes in chemical composition, physical properties and microstructure of duck egg, during salting for up to 14 days, were determined. Duck egg consisted of 10.87% shell, 54.73% egg white and 33.94% yolk. Salting resulted in an increase in weight proportion of egg white, but a decrease in yolk proportion. Moisture contents of both egg white and yolk decreased gradually with

Thammarat Kaewmanee; Soottawat Benjakul; Wonnop Visessanguan

2009-01-01

366

Antioxidant properties and chemical composition of technical Cashew Nut Shell Liquid (tCNSL)  

Microsoft Academic Search

The present study analysed the antioxidant activity of the technical Cashew Nut Shell Liquid (tCNSL) using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay and the xanthine oxidase assay, as well as in vivo evaluation by Saccharomycescerevisiae assay. Also, the chemical composition of tCNSL was determined by gas chromatography–mass spectrometry (GC–MS), revealing the presence of cardanols (40.26%), cardols (29.95%), phytosterol (10.68%), triacontanes (4.66%)

Teresinha de Jesus Aguiar dos Santos Andrade; Bruno Quirino Araújo; Antonia Maria das Graças Lopes Citó; Juliana da Silva; Jenifer Saffi; Marc François Richter; Alexandre de Barros Falcão Ferraz

2011-01-01

367

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.

Cosma, Constantin; Suciu, Ioan; Jantschi, Lorentz; Bolboaca, Sorana D.

2008-01-01

368

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

Microsoft Academic Search

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

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

2011-01-01

369

Botanical and chemical composition of rumen contents of Sika deer on Mt Goyo, northern Japan  

Microsoft Academic Search

Botanical and chemical compositions of the rumen contents of 58 Sika deer on Mt Goyo, northern Japan, collected from summer\\u000a of 1988 to spring of 1989, were analyzed.Sasa nipponica, a dwarf bamboo, was important in summer (35.0%) and winter (61.4%), but it decreased to 5.6% and was replaced by browse\\u000a leaves in fall, and to 28.0% and was replaced by

Seiki Takatsuki; Shoshichi Ikeda

1993-01-01

370

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

371

Chemical Composition and Nutritional Value of Unripe Banana Flour ( Musa acuminata , var. Nanicão)  

Microsoft Academic Search

Banana flour obtained from unripe banana (Musa acuminata, var. Nanicão) under specific drying conditions was evaluated regarding its chemical composition and nutritional value. Results\\u000a are expressed in dry weight (dw). The unripe banana flour (UBF) presented a high amount of total dietary fiber (DF) (56.24 g\\/100 g),\\u000a which consisted of resistant starch (RS) (48.99 g\\/100 g), fructans (0.05 g\\/100 g) and DF without RS or fructans

Elizabete Wenzel Menezes; Carmen Cecília Tadini; Tatiana Beatris Tribess; Angela Zuleta; Julieta Binaghi; Nelly Pak; Gloria Vera; Milana Cara Tanasov Dan; Andréa C. Bertolini; Beatriz Rosana Cordenunsi; Franco M. Lajolo

372

Structural, mechanical, and tribological studies of Cr–Ti–Al–N coating with different chemical compositions  

Microsoft Academic Search

In this paper, a multicomponent hard coating system of Cr–Ti–Al–N has been studied for its structural, mechanical and tribological properties under different chemical compositions. The coatings were deposited onto AISI M42 steel plates by closed-field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique in a gas mixture of Ar+N2. Three processing steps in deposition involved were plasma ion cleaning, buffer layer

P. L. Tam; Z. F. Zhou; P. W. Shum; K. Y. Li

2008-01-01

373

Chemical and mineralogical composition of Surveyor 3 scoop sample 12029,9  

Microsoft Academic Search

Lunar sample 12029,9 consists of soil particles collected from the inner surfaces of the anodized aluminum scoop removed from the Surveyor 3 spacecraft by the Apollo 12 astronauts. The sample was examined by microscopic, semi-micro chemical, X-ray fluorescence, optical emission, and electron-probe methods. Compositional data for the bulk sample and various lithic and mineral components are compared to data from

E. J. Dwornik; C. S. Annell; R. P. Christian; F. Cuttitta; R. B. Finkelman; D. T. Ligon Jr.; H. J. Rose Jr.

1974-01-01

374

Effects of cooking, germination and fermentation on the chemical composition of Nigerian Cowpea ( Vigna unguiculata )  

Microsoft Academic Search

The effects of cooking, germination, and fermentation on the chemical composition of cowpea were studied. There were noticeable trends in the protein, carbohydrate and crude fiber as a result of the different treatments. Both the germinated and fermented samples contained more ether extractable lipids than the raw and cooked samples. Untreated raw cowpea contained 5.9 mg\\/g phytic acid, 1.66 mg\\/g

M. A. Akpapunam; S. C. Achinewhu

1985-01-01

375

Chemical composition, antioxidant and antimicrobial activities of basil ( Ocimum basilicum) essential oils depends on seasonal variations  

Microsoft Academic Search

Chemical composition, antioxidant and antimicrobial activities of the essential oils from aerial parts of basil (Ocimum basilicum L.) as affected by four seasonal, namely summer, autumn, winter and spring growing variation were investigated. The hydro-distilled essential oils content ranged from 0.5% to 0.8%, the maximum amounts were observed in winter while minimum in summer. The essential oils consisted of linalool

Abdullah Ijaz Hussain; Farooq Anwar; Syed Tufail Hussain Sherazi; Roman Przybylski

2008-01-01

376

Compositional and electrical properties of zirconium dioxide thin films chemically deposited on silicon  

Microsoft Academic Search

High-k ZrO2 thin films are grown on p-type silicon by metal-organic chemical vapor deposition based on zirconiumtetrakistrifluoroacetylacetonate as single-source precursor system. Annealing of the as-grown films is performed to investigate the impact of oxidative and reductive atmospheres on thin film properties. The composition of the ultrathin films is examined by Auger spectroscopy, whereas metal-oxide-semiconductor (MOS) structures are employed to extract

S. Harasek; H. D. Wanzenboeck; E. Bertagnolli

2003-01-01

377

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

378

Effect of nanoscale topography and chemical composition of surfaces on their microfrictional behaviour  

Microsoft Academic Search

The influence of nanoscale topography and chemical composition on microfriction has been studied at different humidities. Structured surfaces exhibit lower friction than smooth ones. Among the structured surfaces, the crater-like morphologies show lower friction than pyramid-like morphologies. No significant differences in friction were observed when varying the roughness of the crater-like structures. On pyramid-like morphologies, friction increases with decreasing roughness.

Y. B. Gerbig; S. I.-U. Ahmed; D. G. Chetwynd; H. Haefke

2006-01-01

379

Chemical compositions and bioactivities of crude polysaccharides from tea leaves beyond their useful date  

Microsoft Academic Search

The chemical compositions and bioactivities of crude tea polysaccharides (TPS) from the out-of-date tea leaves (beyond their useful date), namely Xihu Longjing (XTPS), Anxi Tieguanyin (TTPS), Chawentianxia (CTPS) and Huizhoulvcha (HTPS), in market were investigated. These TPS showed similar neutral sugar content and different distribution of molecular weight (1–800kD). These crude TPS were mainly composed of rhamnose, arabinose, galactose, glucose,

Jianbo Xiao; Jianglei Huo; Huixian Jiang; Fan Yang

2011-01-01

380

Essential Oils of Qare-Qat (Vaccinium arctostaphylos) Shoots and Chemical Composition of Berries  

Microsoft Academic Search

Qare-Qat or Iranian Vaccinium (V.arctostaphylos L.) is a shrub that grows in the north of Iran. The fruits of Qare-Qat were collected from natural habitats and examined for chemical composition such as minerals. The results showed that the ripe fruit of V.arctostaphylos L. had 30.6% sugars, 15.5% protein, 1.5% total fat and 2% soluble solids. Dry matter, nitrogen and calcium

SHAHRAM SEDAGHATHOOR; A. K. KASHI; A. R. TALAEI; A. KHALIGHI

381

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

Microsoft Academic Search

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

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

2010-01-01

382

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

383

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

Microsoft Academic Search

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

Melak H. Mengesha

1966-01-01

384

Sucrose fatty acid sulphate esters as novel vaccine adjuvants: effect of the chemical composition  

Microsoft Academic Search

Adjuvant activity of novel, synthetic sucrose derivatives towards a recombinant glycoprotein was determined in large, non-rodent animal species. Compared to antigen alone, up to 3000-fold higher virus neutralizing antibody titres (VNTs) and 10-fold higher cellular responses against classical swine fever virus were observed in pigs after two immunizations with the sucrose derivatives combined with a squalane-in-water emulsion. The chemical composition

Anneke G. Blom; Luuk A. Th. Hilgers

2004-01-01

385

Chemical composition of rainwater and anthropogenic influences in Chengdu, Southwest China  

Microsoft Academic Search

A comprehensive study on the chemical compositions of rainwater was carried out from Jan. to Dec. in 2008 in Chengdu, a city located on the acid rain control zone of southwest China. All samples were analyzed for pH and major ions (F–, Cl?, NO3?, SO42?, K+, Na+, Ca2+, Mg2+, and NH4+). The pH increased due to the result of neutralization

Hua Wang; Guilin Han

2011-01-01

386

Chemical composition and antibacterial activity of the essential oil of Pinus caribaea from Nigeria  

Microsoft Academic Search

The chemical composition of the essential oil obtained from the needles of Pinus caribaea by hydrodistillation was analyzed by Gas Chromatography-Mass Spectrometry. A total of twenty nine compounds, representing 93.8% of the oil were identified. The major constituents of the essential oil were ?-phellandrene (67.9%), ?-caryophyllene (10.2%) and ?-pinene (5.4%). High concentration of ?- phellandrene in the oil suggests its

O. Oluwadayo Sonibare; K. Olakunle

2008-01-01

387

Preparation, chemical composition and storage studies of quamachil ( Pithecellobium dulce L.) aril powder  

Microsoft Academic Search

Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging\\u000a systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively.\\u000a The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril

Galla Narsing Rao; Allani Nagender; Akula Satyanarayana; Dubasi Govardhana Rao

2011-01-01

388

Nanotubules on plant surfaces: Chemical composition of epicuticular wax crystals on needles of Taxus baccata L  

Microsoft Academic Search

Needles of Taxus baccata L. were covered with tubular epicuticular wax crystals varying in diameters (100 and 250nm) and lengths (300–500 and 500–1000nm) on the abaxial and adaxial surfaces, respectively. Various sampling protocols were employed to study the chemical composition of the needle waxes on three different levels of spatial resolution. First, a dipping extraction of whole needles yielded the

Miao Wen; Christopher Buschhaus; Reinhard Jetter

2006-01-01

389

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

Microsoft Academic Search

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

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

1999-01-01

390

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

391

Effect of hexoestrol implantation and body size on the chemical composition and body components of chickens  

Microsoft Academic Search

Two groups of meat?type cockerels, 56 d of age, from the same hatch but of different mean live?weights (1135 g ± SD 96.2 and 544 g ± 72.0) due to differences in earlier nutritional treatments were implanted with hexoestrol to determine the effects on food consumption, live?weight gain, carcass gain, chemical composition of carcass and offal, and weight of some

J. W. Ryley; K. W. Moir; Patricia M. Pepper; H. W. Burton

1970-01-01

392

Chemical whole-body composition of the 20 kg liveweight growing pig  

Microsoft Academic Search

The chemical whole-body composition of 20 Landrace × (Landrace × Large White) pigs of 20 kg liveweight was determined. Mean (± SD) body protein, lipid, ash, and water contents (%) were 15.9 ± 1.47, 14.2 ± 2.72, 3.7 ± 0.43, and 65.6 ± 2.61, respectively. These values agreed closely with mean estimates derived from a review of the world literature.

C. H. M. Smits; P. J. Moughan; W. C. Smith

1988-01-01

393

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

394

Composition and Chemical Variation of the Essential Oil of Lepechinia salviaefolia (Kunth) Epl. from Venezuela  

Microsoft Academic Search

The chemical composition of the leaf oil of Lepechinia salviaefolia (Kunth) Epl. was determined by means of GC and GC\\/M S. Plant material from 60 individual plants was investigated and the quantitative oil data were analyzed by a multivariate statistical analysis revealing two chemotypes. The major constituents of the palustrol-type (28 samples) were (-)-palustrol (19.1%), ?-phellandrene (13.8%), borneol (11.8%) and

Maren D. Eggers; Giovannina Orsini; Elisabeth Stahl-Biskup

2001-01-01

395

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.

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

2007-01-01

396

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

397

Development of chemical vapor composite (CVC) ceramic materials. Status report, April 1995--June 1997  

SciTech Connect

The objective of the 94 DOE Chemical Vapor Composites (CVC) ceramics materials grant is to develop a reliable and flexible process to produce, in a single step, ceramic composites to final shape. This report is a brief summary of activities in the development of the CVC ceramics materials. Equipment has been designed and built to fabricate CVC silicon carbides with fibers such as Nextel, Nicalon, and carbon. Materials and shapes have been fabricated and characterized as to physical and mechanical properties and microstructure. Details will be given in the final report.

NONE

1997-07-25

398

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

399

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

2010-11-02

400

Chemical composition and bioactivity of different oregano (Origanum vulgare) extracts and essential oil.  

PubMed

BACKGROUND: There is a growing interest in industry to replace synthetic chemicals by natural products with bioactive properties. Aromatic plants are excellent sources of bioactive compounds that can be extracted using several processes. As far as oregano is concerned, studies are lacking addressing the effect of extraction processes in bioactivity of extracts. This study aimed to characterise the in vitro antioxidant and antibacterial properties of oregano (Origanum vulgare) essential oil and extracts (in hot and cold water, and ethanol), and the chemical composition of its essential oil. RESULTS: The major components of oregano essential oil were carvacrol, ?-fenchyl alcohol, thymol, and ?-terpinene. Hot water extract had the strongest antioxidant properties and the highest phenolic content. All extracts were ineffective in inhibiting the growth of the seven tested bacteria. In contrast, the essential oil inhibited the growth of all bacteria, causing greater reductions on both Listeria strains (L. monocytogenes and L. innocua). CONCLUSION: O. vulgare extracts and essential oil from Portuguese origin are strong candidates to replace synthetic chemicals used by the industry. © 2013 Society of Chemical Industry. PMID:23553824

Teixeira, Bárbara; Marques, António; Ramos, Cristina; Serrano, Carmo; Matos, Olívia; Neng, Nuno R; Nogueira, José M F; Saraiva, Jorge Alexandre; Nunes, Maria Leonor

2013-02-01

401

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

PubMed

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

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

2012-08-07

402

Chemical composition changes in eucalyptus and pinus woods submitted to heat treatment.  

PubMed

This study investigated the influence of heat treatment on the chemical composition of Eucalyptus saligna and Pinus caribaea var. hondurensis woods to understand its role in wood processing. E. saligna and P. caribaea var. hondurensis woods were treated in a laboratorial electric furnace at 120, 140, 160 and 180 degrees C to induce their heat treatment. The chemical composition of the resulting products and those from original wood were determined by gas chromatography. Eucalyptus and Pinus showed a significant reduction in arabinose, manose, galactose and xylose contents when submitted to increasing temperatures. No significant alteration in glucose content was observed. Lignin content, however, increased during the heat process. There was a significant reduction in extractive content for Eucalyptus. On the other hand, a slight increase in extractive content has been determined for the Pinus wood, and that only for the highest temperature. These different behaviors can be explained by differences in chemical constituents between softwoods and hardwoods. The results obtained in this study provide important information for future research and utilization of thermally modified wood. PMID:18586488

Brito, J O; Silva, F G; Leão, M M; Almeida, G

2008-06-30

403

Chemical composition of the attachment pad secretion of the locust Locusta migratoria.  

PubMed

This study is the first attempt to characterise the chemical composition of the secretion of the smooth pads of the locust Locusta migratoria and to relate this to the composition of the cuticle coverage of the pads and the wings. Gas-chromatography and mass-spectrometry (GC-MS) were the principal techniques used for the characterization of these materials. Secretion droplets were visualised and quantified with the aid of diverse microscopic techniques. The chemical composition of prints is shown to differ from the cuticle coverage, in particular, with respect to the fatty acid distribution: in the secretion, saturated and unsaturated fatty acids with chain lengths between C(16) and C(20) in both the free form and as glycerides predominate, whereas cuticle coverage contains waxes of long-chained fatty-acids bound to long-chain primary alcohols. The second important difference is the significant amount of glucose and other saccharides found in methanolyzates of the pad fluid. A considerable amount of the amino acids (up to 53%) was detected in the non-volatile portion of the fluid. Data obtained from the shock-freezing, carbon-platinum coating and replica preparation show that the secretory droplets contain nano-droplets on their surfaces. The results lead us to suggest that the pad secretion is an emulsion consisting of lipidic nano-droplets dispersed in an aqueous liquid. According to the chemical composition of the secretion, a high-viscosity of the fluid may be suggested. Presumably, the fluid is a kind of a coupling agent, promoting and strengthening adhesion between otherwise incompatible materials by providing the proximity of contact for intermolecular forces. PMID:12429112

Vötsch, W; Nicholson, G; Müller, R; Stierhof, Y-D; Gorb, S; Schwarz, U

2002-12-01

404

Body chemical composition of Nellore bulls with different residual feed intakes.  

PubMed

Empty body and carcass chemical compositions, expressed as content of water, ether extract, protein, minerals, and energy, were evaluated in Nellore bulls with different residual feed intakes (RFI). Forty-nine not castrated males, with 343 kg of average initial BW and 398 kg of average slaughter BW, were studied. Animals were divided in two subgroups: reference group (RG) and ad libitum feeding group. At the end of the adaptation period, animals of subgroup RG were slaughtered and the other animals were finished in individual pens for approximately 100 d, until they reached a subcutaneous fat thickness over the LM of 4 mm, and were slaughtered at an average age of 540 d. Body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Tissue deposition rates and chemical composition of gain were also measured based on gains estimated by comparative slaughter technique. No significant differences in slaughter BW (P = 0.8639), empty BW (P = 0.7288), HCW (P = 0.6563), or empty body and carcass rates of gain were observed between RFI groups, demonstrating that the low (-0.331 kg DM/d) and high (+0.325 kg DM/d) RFI animals presented similar body sizes and growth rates. No significant differences in empty body or carcass content of water, ether extract, protein, minerals, and energy were observed between the low and high RFI animals. And also there were no significant differences in empty BW or carcass gain, demonstrating that low and high RFI animals had a similar growth potential. More efficient animals (low RFI) consumed less feed than less efficient animals (high RFI) but presented similar body sizes, growth rates, and empty body and carcass chemical composition. PMID:23658334

Bonilha, E F M; Branco, R H; Bonilha, S F M; Araujo, F L; Magnani, E; Mercadante, M E Z

2013-05-08

405

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

406

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

407

Recent progress of propolis for its biological and chemical compositions and its botanical origin.  

PubMed

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

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

2013-04-30

408

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

PubMed

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

Sedda, Antioco Franco; Rossi, Gabriele

2010-07-01

409

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

410

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

SciTech Connect

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

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

2012-07-15

411

High-yield boron nitride nanosheets from 'chemical blowing': towards practical applications in polymer composites.  

PubMed

An improved 'chemical blowing' route presuming atmospheric-pressure pre-treatment and moderate heating rate of designated precursors was developed to synthesize ultra-thin boron nitride (BN) nanosheets with high yield and large lateral dimensions. The yield reached as high as 40 wt% with respect to raw materials (ammonia borane). The strong oxygen-related ultraviolet luminescence together with a blue emission of these BN nanosheets was then documented and analyzed. This implies potential applications in solid-state lighting, ultraviolet lasing and full-color luminescence. Mechanical strength of different polymeric composites with a small fraction of BN nanosheet fillers was dramatically increased by tens of per cent, while high transparency of composite materials was still maintained in the visible optical range. The increased yield and reduced cost of BN nanosheets should promote their wide practical applications in various composites. PMID:22820508

Wang, Xuebin; Pakdel, Amir; Zhi, Chunyi; Watanabe, Kentaro; Sekiguchi, Takashi; Golberg, Dmitri; Bando, Yoshio

2012-07-20

412

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

Microsoft Academic Search

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

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

413

Identification of 5-hydroxytryptamine 1A receptor agents using a composite pharmacophore analysis and chemical database screening  

Microsoft Academic Search

A composite pharmacophore analysis and computer-assisted chemical database screening were used to identify a previously unrecognized class of 5-hydroxytryptamine1A (5-HT1A) receptor active agents. An analysis of published data led to the identification of 20 different chemical structures which share nanomolar affinity for the 5-HT1A receptor. From a composite pharmacophore analysis of all 20 potent agents, we hypothesized that compounds containing

Andrew J. Sleight; Stephen J. Peroutka

1991-01-01

414

Relationship between surface morphology and chemical composition of spheroidal carbonaceous particles within sediment core samples recovered from Osaka Bay, Japan  

Microsoft Academic Search

Spheroidal carbonaceous particles (SCPs) are produced by the high-temperature combustion of fossil fuels and are emitted to\\u000a the atmosphere. Previous studies are divided regarding whether SCPs derived from the combustion of various fossil fuels can\\u000a be identified based on their surface morphologies and chemical compositions. In this study, we examined the surface morphology\\u000a and chemical composition of SCPs in sediment

Akiko Murakami-Kitase; Takamoto Okudaira; Jun Inoue

2010-01-01

415

Investigations of surface morphology and chemical composition of Ag\\/ZnS\\/glassceramic thin-film structure  

Microsoft Academic Search

The surface morphology and chemical composition of Ag\\/ZnS\\/glassceramic thin-film system obtained by close-spaced vacuum sublimation technique under different grow conditions were investigated. Examination of surface profile and morphology was performed by scanning electron and optical microscopy. Chemical composition was studied by Rutherford back scattering method. Results of morphology studies enabled to determine dependence of the growth mechanism, roughness Ra, grain

D. Kurbatov; A. Opanasyuk; V. Denisenko; A. Kramchenkov

416

Influence of a series of organic and chemical substances on the translucency of resin composites.  

PubMed

The objective of this study was to investigate the changes in the translucency of resin composites following a series of immersion treatments in organic and chemical substances. Color of resin composites was measured according to the CIELAB color scale relative to the standard illuminant D65 over a white and a black background. Translucency parameter (TP) of resin composites was calculated at baseline, and after sequential immersion: Step 1, porcine liver esterase (a substitute for a salivary esterase); Step 2, organic substances (mucin and serum) and phosphate-buffered saline (PBS) as a control; Step 3, chemical alteration agents [chlorhexidine (CH) and carbamide peroxide (CP)]; and Step 4, 2% methylene blue. Porcine liver esterase caused small changes in TP (DeltaTP = -0.5 to 0.2). After Step 2, DeltaTP values of three groups were similar in the range of -0.7 to 1.2. After Step 3, DeltaTP values of all groups were small in the range of -1.5 to 2.2. After Step 4, DeltaTP values were high and differences that varied by the resin composite and the immersion protocol were clearly observed (DeltaTP = -13.4 to -2.5). Changes in TP were mainly influenced by resin composite. After Step 4, mucin and serum groups showed generally small changes in TP compared to PBS group. It is a possibility that the high changes in TP after immersion in methylene blue is an indication of dye absorption which might be an indication of the degree of resin composite degradation. PMID:16184537

Kim, Ji-Hyung; Lee, Yong-Keun; Powers, John M

2006-04-01

417

Effect of season on heavy metal contents and chemical compositions of chub mackerel (Scomber japonicus) muscle.  

PubMed

Seasonal variations of heavy metals concentrations and overall chemical compositions were determined in chub mackerel caught in the Southern Sea of Korea. The average mercury and lead content varied between 0.04 and 0.08 mg/kg and between 0.01 and 0.02 mg/kg, respectively. Seasonal variations were not detected in lead, but mercury displayed maximal values in winter (P < 0.05). A distinct seasonal pattern was found in crude fat content with maximal values in December and minimal values in April. Fatty acid composition showed that monounsaturated fatty acids levels were the highest in August, while polyunsaturated fatty acids (PUFA) levels were the highest in April. The major contributing factors to the seasonal variation of PUFA amounted to 20:5n-3 and 22:6n-3. The total amino acids content varied from 180.6 to 187.7 mg/g. There were no significant seasonal variations in total amounts of amino acids. Practical Application:? Mackerel (Scomber japonicus) is one of the most important fishing resources in Korea. The effects of polyunsaturated fatty acids (PUFA) on the human body have been identified, and consequently, the intake of fish lipids has steadily increased among the human population. There have been few studies on safety and alterations in chemical composition of mackerel attributed to seasonal fluctuations. Therefore, the results presented in this study could be used to improve the safety and nutrition information available to consumers. PMID:22251075

Bae, J H; Lim, S Y

2012-01-17

418

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

PubMed

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

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

419

Formation of the chemical composition of transition metal dichalcogenide thin films at pulsed laser deposition  

NASA Astrophysics Data System (ADS)

The formation of the chemical composition of dichalcogenide films at pulsed laser deposition in vacuum and in rarefied gases (Ar, H2) is investigated with MoSe x thin-film coatings. It is found that deposition in gases increases the selenium concentration and somewhat flattens the composition over the substrate surface. To elucidate the mechanisms underlying the MoSe x film formation, a computer model is used that simulates the motion of a pulsed laser-initiated atomic flux through a rarefied gaseous medium. Using this model, the energy and angular parameters of atomic Mo and Se fluxes toward the substrate are calculated. It is shown that the expansion dynamics of laser plume components (Mo and Se) and the selective sputtering of selenium are the main factors governing the formation of the chemical composition and its distribution over the substrate. The influence of the sort of gas on the efficiency of atomic flux slowdown and scattering and on material losses during deposition is considered.

Fominski, V. Yu.; Romanov, R. I.; Gnedovets, A. G.; Nevolin, V. N.

2010-10-01

420

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

421

Ion-molecule reactions and chemical composition of emanated from herculane spa geothermal sources.  

PubMed

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 CH(4) (+) ions that appear under the action of radiation are the starting point of these reactions. The presence of hydrogen in the emanated gases may be also a result of these reactions. PMID:19325844

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

2008-06-20

422

Chemical composition and antibacterial activity of essential oil of Heracleum rechingeri Manden from Iran.  

PubMed

The chemical composition of the essential oil from Heracleum rechingeri was analysed using GC-MS. Twenty-seven compounds, accounting for 94.62% of the extracted essential oil, were identified. The main oil compounds were octyl acetate (29.49%), elemicine (23.06%), (E)-caryophyllene (9.26%), caryophyllene oxide (6.42%), terpinolene (6.12%) and (Z)-3-octenyl acetate (4.72%). The antimicrobial activity of the essential oil was tested against three different bacteria by disc diffusion method and showed maximum inhibitory activity against Gram-positive bacteria, especially Bacillus subtilis. PMID:20552523

Habibi, Zohreh; Eshaghi, Rasool; Mohammadi, Mehdi; Yousefi, Maryam

2010-07-01

423

Chemical composition and biological activities of the essential oils from Duguetia lanceolata St. Hil. barks.  

PubMed

Essential oils of Duguetia lanceolata barks, obtained at 2 (T2) and 4 h (T4), were identified by gas chromatography and gas chromatography/mass spectrometry. ?-elemene (12.7 and 14.9%), caryophyllene oxide (12.4 and 10.7%) and ?-selinene (8.4 and 10.4%) were the most abundant components in T2 and T4, respectively. The essential oils inhibited the growth of Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Candida albicans. The essential oils were cytotoxic against brine shrimp. The extraction time influenced the chemical composition and biological activities of essential oils obtained from the barks of D. lanceolata. PMID:22976469

Sousa, Orlando V; Del-Vechio-Vieira, Glauciemar; Alves, Maria S; Araújo, Aílson A L; Pinto, Míriam A O; Amaral, Maria P H; Rodarte, Mírian P; Kaplan, Maria A C

2012-09-13

424

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

Microsoft Academic Search

High-resolution UCLES\\/AAT spectra of four B-type supergiants in the SMC South\\u000aEast Wing have been analysed using non-LTE model atmosphere techniques to\\u000adetermine their atmospheric parameters and chemical compositions. The principle\\u000aaim of this analysis was to determine whether the very low metal abundances\\u000a($-$1.1 dex compared with Galactic value) previously found in the Magellanic\\u000aInter Cloud region (ICR) were

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

2004-01-01

425

Analysis of the chemical composition of essential oil from Algerian Inula viscosa (L.) Aiton  

Microsoft Academic Search

The chemical composition of the essential oil of Inula viscosa (L.) leaves, obtained by both hydrodistillation and steam distillation, was investigated by GC–MS. The major components for hydrodistillation were: 12-carboxyeudesma-3,11 (13) diene (28.88%); linolenic acid (7.80%); palmitic acid (5.38%); butyl hydroxy toluene (4.11%) and fokienol (3.37%), while for steam distillation were: 12-carboxyeudesma-3,11 (13) diene (56.81%); 2,3-didehydrocostic acid (3.25%); butyl hydroxy

Imad Eddine Haoui; Ratiba Derriche; Leila Madani; Zahia Oukali

426

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

Microsoft Academic Search

The effect of the 248-nm KrF and 355-nm YAG:Nd3+ laser radiation on the surface morphology and chemical composition of SrTiO3, Sr2RuO4, PbMoO4, LiNbO3, Y3Al5O12, and Al2O3 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

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

2011-01-01

427

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

Microsoft Academic Search

The effect of the 248-nm KrF and 355-nm YAG:Nd{sup 3+} laser radiation on the surface morphology and chemical composition of SrTiOâ, SrâRuOâ, PbMoOâ, LiNbOâ, YâAlâOââ, and AlâOâ 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

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

2011-01-01

428

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

2011-09-08

429

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

430

The chemical composition and manufacturing technology of pottery types at Udhruh, Southern Jordan  

NASA Astrophysics Data System (ADS)

This paper presents laboratory analyses of selected pottery sherds from the ancient site of Udhruh in southern Jordan. The site exhibits pottery sherds from Nabataean times up to the late Islamic period. However, in this study the samples were randomly chosen. The analyses were carried out using a scanning electron microscope equipped with specialist software. The paper establishes the historical context of Udhruh, the methodology employed, and the results of the study. The results reveal differences in the chemical composition of samples, and a variety of manufacturing techniques, only some of which appear to have been of local inspiration.

Shquiarat, M.; Abudanh, F.; Alnawafleh, H.

431

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

Microsoft Academic Search

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

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

432

Chemical composition and antimicrobial activity of the essential oils of Anthemis xylopoda O. Schwarz from Turkey.  

PubMed

The chemical composition and the antimicrobial activity of the essential oils isolated from the leaves (LEO) and flowers (FEO) of Anthemis xylopoda, an endemic taxon of Turkey, were investigated. Borneol was the major constituent of both the oils studied (30.15 and 31.85%, respectively). The antimicrobial activities of both oils were separately evaluated against 13 microorganisms. The disc diffusion method was used for the antimicrobial activity test. Results showed that both oils of Anthemis xylopoda exhibited a significant antimicrobial activity. PMID:15507328

Uzel, A; Guvensen, A; Cetin, E

2004-12-01

433

Chemically treated kindling and process  

SciTech Connect

A chemically treated kindling and process for the production thereof wherein the kindling is comprised of a pressed mixture of wood fibers, alum, and cornstarch, and is saturated with a prepared composition comprising a plurality of chemically distinct compositions, each of the compositions containing a different predetermined amount of refined petroleum wax and refined oil.

Earlywine, R.T.

1984-10-09

434

Correlation of transverse and rotational diffusion coefficient: a probe of chemical composition in hydrocarbon oils.  

PubMed

Measurements of relaxation time and diffusion coefficient by nuclear magnetic resonance are well-established techniques to study molecular motions in fluids. Diffusion measurements sense the translational diffusion coefficients of the molecules, whereas relaxation times measured at low magnetic fields probe predominantly the rotational diffusion of the molecules. Many complex fluids are composed of a mixture of molecules with a wide distribution of sizes and chemical properties. This results in correspondingly wide distributions of measured diffusion coefficients and relaxation times. To first order, these distributions are determined by the distribution of molecular sizes. Here we show that additional information can be obtained on the chemical composition by measuring two-dimensional diffusion-relaxation distribution functions, a quantity that depends also on the shape and chemical interactions of molecules. We illustrate this with experimental results of diffusion-relaxation distribution functions on a series of hydrocarbon mixtures. For oils without significant amounts of asphaltenes, the diffusion-relaxation distribution functions follow a power-law behavior with an exponent that depends on the relative abundance of saturates and aromatics. Oils with asphaltene deviate from this trend, as asphaltene molecules act as relaxation contrast agent for other molecules without affecting their diffusion coefficient significantly. In waxy oils below the wax appearance temperature a gel forms. This is reflected in the measured diffusion-relaxation distribution functions, where the restrictions due to the gel network reduce the diffusion coefficients without affecting the relaxation rates significantly. PMID:18335907

Mutina, Albina R; Hürlimann, Martin D

2008-03-12

435

Variation in chemical composition and acaricidal activity against Dermanyssus gallinae of four eucalyptus essential oils.  

PubMed

The results of this study suggest that certain eucalyptus essential oils may be of use as an alternative to synthetic acaricides in the management of the poultry red mite, Dermanyssus gallinae. At a level of 0.21 mg/cm(2), the essential oil from Eucalyptus citriodora achieved 85% mortality in D. gallinae over a 24 h exposure period in contact toxicity tests. A further two essential oils from different eucalyptus species, namely E. globulus and E. radiata, provided significantly (P < 0.05) lower mite mortality (11 and 19%, respectively). Notable differences were found between the eucalyptus essential oils regarding their chemical compositions. There appeared to be a trend whereby the essential oils that were composed of the fewer chemical components were the least lethal to D. gallinae. It may therefore be the case that the complexity of an essential oil's chemical make up plays an important role in dictating the toxicity of that oil to pests such as D. gallinae. PMID:19089590

George, David R; Masic, Dino; Sparagano, Olivier A E; Guy, Jonathan H

2008-12-17

436

Dissolved Organic Matter Discharge from the Six Largest Arctic Rivers: Chemical Composition and Seasonal Variability  

NASA Astrophysics Data System (ADS)

The vulnerability of the Arctic to climate change has been realized due to disproportionately large increases in surface air temperatures. Effects of this temperature shift are widespread in the Arctic but likely include changes to the hydrological cycle and permafrost thaw, which have implications for the transport of organic carbon from the watersheds into rivers. The focus of this research was to describe the seasonal variability of the chemical composition of dissolved organic matter (DOM) in the six largest Arctic rivers (Yukon, Mackenzie, Ob, Yenisei, Lena and Kolyma) using optical properties (UV-Vis Absorbance and Fluorescence) and lignin phenol analysis. We also investigated differences between rivers and how watershed characteristics influence DOM composition. Dissolved organic carbon (DOC) concentrations followed the hydrograph with highest concentrations measured during snowmelt. The six rivers studied here shared a similar seasonal pattern and chemical composition. There were, however, large differences between rivers in terms of total carbon discharge reflecting the differences in watershed characteristics such as climate, catchment size, river discharge, slope, elevation, soil types, and permafrost distribution. Carbon and lignin flux estimates were highest from the large Siberian rivers (Lena, Yenisei), with a large proportion of permafrost. Although the Kolyma and Mackenzie rivers had the smallest carbon and lignin flux estimates; the Kolyma exported about twice the amount of organic material annually. Multiple linear regressions of the carbon (kg DOC km2 yr-1) export indicate the most important predictors are maximum elevation, temperature and percentage of continuous permafrost (Adj R2=0.45, p=0.05). Similarly, the most important predictors of lignin (kg lignin km2 yr-1) export were slope, maximum elevation, temperature and percentage of continuous permafrost (Adj R2=0.89, p<<0.001). The chemical composition of DOM during peak flow indicates a dominance of freshly leached material with elevated aromaticity, larger molecular weight, and elevated lignin yields relative to baseflow DOM. The seasonal difference in DOM quality likely reflects increased microbial processing of soil and river organics during summer. Other factors influencing the concentration and composition of river DOM include flow path (surface run off versus percolation) and sorption to different mineral soils.

Rinehart, A. J.; Amon, R. M.; Louchourarn, P.; Duan, S.; Peterson, B. J.; McClelland, J. W.; Holmes, R. M.

2008-12-01

437

Interspecies differences in the empty body chemical composition of domestic animals.  

PubMed

Domestication of animals has resulted in phenotypic changes by means of natural and human-directed selection. Body composition is important for farm animals because it reflects the status of energy reserves. Thus, there is the possibility that farm animals as providers of food have been more affected by human-directed selection for body composition than laboratory animals. In this study, an analysis was conducted to determine what similarities and differences in body composition occur between farm and laboratory animals using literature data obtained from seven comparative slaughter studies (n = 136 observations). Farm animals from four species (cattle, goats, pigs and sheep) were all castrated males, whereas laboratory animals from three species (dogs, mice and rats) comprised males and/or females. All animals were fed ad libitum. The allometric equation, Y = aX b , was used to determine the influence of species on the accretion rates of chemical components (Y, kg) relative to the growth of the empty body, fat-free empty body or protein weights (X, kg). There were differences between farm and laboratory animals in terms of the allometric growth coefficients for chemical components relative to the empty BW and fat-free empty BW (P < 0.01); farm animals had more rapid accretion rates of fat (P < 0.01) but laboratory animals had more rapid accretion rates of protein, water and ash (P < 0.01). In contrast, there was no difference in terms of the allometric growth coefficients for protein and water within farm animals (P > 0.2). The allometric growth coefficients for ash weight relative to protein weight for six species except sheep were not different from a value of 1 (P > 0.1), whereas that of sheep was smaller than 1 (P < 0.01). When compared at the same fat content of the empty body, the rate of change in water content (%) per unit change in fat content (%) was not different (P > 0.05) across farm animal species and similar ash-to-protein ratios were obtained except for dogs. The fraction of empty body energy gain retained as fat increased in a curvilinear manner, and there was little variation among farm animals at the same fat content of the empty body. These findings may provide the opportunity to develop a general model to predict empty body composition across farm animal species. In contrast, there were considerable differences of chemical body composition between farm and laboratory animals. PMID:23438510

Maeno, H; Oishi, K; Hirooka, H

2013-02-26

438

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

2012-11-20

439

Compositional and electrical properties of zirconium dioxide thin films chemically deposited on silicon  

NASA Astrophysics Data System (ADS)

High-k ZrO2 thin films are grown on p-type silicon by metal-organic chemical vapor deposition based on zirconiumtetrakistrifluoroacetylacetonate as single-source precursor system. Annealing of the as-grown films is performed to investigate the impact of oxidative and reductive atmospheres on thin film properties. The composition of the ultrathin films is examined by Auger spectroscopy, whereas metal-oxide-semiconductor (MOS) structures are employed to extract electrical characteristics. Equivalent oxide thicknesses down to 2 nm and interface trap densities of 5×1011 cm-2 eV-1 at midgap are obtained. MOS capacitors show extremely low leakage currents, promising to reduce gate leakage by more than a factor of 103 compared to SiO2. The correlation between compositional and electrical properties is discussed on the basis of postdeposition annealing procedures resulting in a consistent explanation of the observed effects.

Harasek, S.; Wanzenboeck, H. D.; Bertagnolli, E.

2003-05-01

440

Chemical composition of heavy coker gasoil and products from its adsorptive treatment  

SciTech Connect

The expansion of electrode coke production by delayed coking has led to an increase in the amounts of light and heavy gasoils in the refinery balance. Uses chromatographic separation and mass spectrometry to investigate the hydrocarbon composition of the heavy gasoil from delayed coking of a thermally cracked distillate feed, produced from a mixture of medium-sulfur crudes. Examines the products obtained from this coker gasoil by adsorptive treatment to upgrade the material. Shows that delayed coker gasoils, with respect to chemical composition, are unique products from petroleum processing. Finds that by treatment in a moving bed by aluminosilica adsorbent, with proper adjustment of the ratio of adsorbent to feedstock, practically resin-free, highly aromatic oils can be obtained, differing in the contents of individual types of polycyclic aromatic hydrocarbons, with about 55% of such hydrocarbons in the desorbed oil and about 30% in the oil that is the principal product.

Alekhina, N.I.; Levinson, S.Z.; Mikhailov, I.A.

1983-03-01

441

Simple chemical solution coating and gas sensing properties of ?-Fe2O3/chrysotile fibrous composites  

NASA Astrophysics Data System (ADS)

?-Fe2O3/chrysotile fibrous composites were prepared by a simple chemical solution coating method for the gas sensitivity improvement of ?-Fe2O3. X-ray diffraction (XRD) and atomic force microscope (AFM) analyses indicate that corundum-type ?-Fe2O3 nanoparticles with a mean particle size ˜20 nm are dense and well-proportioned on the surface of chrysotile fibers due to the mechanism that positively charged Fe(OH)3 particles can be adsorbed onto the negatively charged chrysotile fibers in acidic liquids. The fabricated sensor devices were characterized for their electrical and gas sensing properties, it is found that the sensitivities of ?-Fe2O3/chrysotile fibrous composites to H2 and CH4 all increase by ˜35% than those of the single ?-Fe2O3 nanoparticles. Such simple coating treatment is an effective way in improving the continuities and gas sensing properties of nanogranular thick films.

Liu, Haifeng; Peng, Tongjiang; Ma, Guohua; Sun, Hongjuan; Hu, Hailong

2012-03-01

442

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

PubMed

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

Sharopov, Farukh S; Setzer, William N

2011-05-01

443

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

PubMed

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

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

2012-09-07

444

Composition control of manganite perovskites in metalorganic chemical vapor deposition with in situ spectroscopic monitoring  

NASA Astrophysics Data System (ADS)

Using in situ infrared absorption spectroscopy, the behavior of the film precursors, tris(dipivaloylmethanato)lanthanum [La(DPM)3], tris(dipivaloylmethanato)manganese [Mn(DPM)3], and bis(dipivaloylmethanato)strontium [Sr(DPM)2], in the gas phase was investigated under actual chemical vapor deposition conditions of manganite perovskites. The temperature dependence of the infrared absorption indicates that La(DPM)3, Mn(DPM)3, and Sr(DPM)2 differ significantly in the decomposition temperature. The atomic composition of the deposited film can be controlled on the basis of the precursor densities obtained by the in situ spectroscopic measurements. The composition control based on the in situ monitoring technique is expected to improve the reproducibility of the magnetic property of the deposited film.

Nakamura, Toshihiro; Tai, Ryusuke; Nishimura, Takuro; Tachibana, Kunihide

2005-05-01

445

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

446

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

447

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

448

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

NASA Astrophysics Data System (ADS)

We present a new statistical method to construct a model for the chemical composition of Earth's primitive mantle along with its variance. Earth's primitive mantle is located on the melting trend exhibited by the global compilation of mantle peridotites, using cosmochemical constraints on the relative abundances of refractory lithophile elements (RLE). This so-called pyrolite approach involves the least amount of assumptions, thereby being probably most satisfactory compared to other approaches. Its previous implementations, however, suffer from questionable statistical treatment of noisy geochemical data, leaving the uncertainty of model composition poorly quantified. In order to properly take into account how scatters in peridotite data affect this geochemical inference, we combine the following statistical techniques: (1) modeling a nonlinear melting trend in the multidimensional compositional space through the principal component analysis, (2) determining the primitive mantle composition on the melting trend by simultaneously imposing all of cosmochemical constraints with least squares, and (3) mapping scatters in original data into the variance of the final model through the bootstrap resampling technique. Whereas our model is similar to previous models in terms of Mg, Si, and Fe abundances, the RLE contents are at ˜2.16 ± 0.37 times the CI chondrite concentration, which is lower than most of previous estimates. The new model is depleted by >20% in a number of incompatible elements including heat-producing elements, U, Th, and K, and this depleted nature is further amplified (up to 60%) in terms of predicted composition for the present-day mantle.

Lyubetskaya, Tanya; Korenaga, Jun

2007-03-01

449

The chemical composition of nanoparticles formed from the oxidation of real plant emissions  

NASA Astrophysics Data System (ADS)

Organic vapors from biosphere emissions clearly participate in the formation of secondary organic aerosol (SOA). Thereby volatile organic compounds (VOCs) are transformed by photolytic reactions to low volatility organic compounds capable of condensing onto particles even in a size range where the strong curvature typically prevents vapor condensation by most other condensable vapors (Kelvin effect). However, the exact compounds responsible for nanoparticle formation and growth largely remain unknown. In this study we conducted chamber experiments under well-defined conditions to investigate chemical and physical properties of aerosol particles formed from oxidation products of real plant emissions. The chamber used comprises of a 10 m^3 Teflon FEP bag, operated at room temperature. Emissions from specific plants, e.g., a pine tree, can be added to the chamber and may produce aerosol particles after oxidation with ozone and/or OH. Gas chromatographs, trace gas analyzers, and aerosol sizing instruments provide a comprehensive set of instruments to analyze gas phase composition and aerosol size distribution. The chemical composition of nanoparticles at a pre-selected size is analyzed with the thermal desorption chemical ionization mass spectrometer (TDCIMS) (Smith & Rathbone, Int. J. Mass Spectrom. 274, 8 (2008)) providing positive and negative ion mass spectra with a time resolution of about 10 minutes. Here we present results from the emissions of ponderosa pine, the dominant tree species in the Rocky Mountains. These data are directly compared to measurements obtained by the TDCIMS during the BEACHON-SRM08 field campaign, which took place from 15 July - 15 August 2008 at the NCAR Manitou Forest Observatory near Woodland Park, CO. This comparison also gives insight into the ability of these chambers to simulate biogenic SOA formation.

Winkler, P. M.; Ortega, J.; Barsanti, K. C.; Friedli, H. R.; Smith, J. N.

2010-12-01

450

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

SciTech Connect

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

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

1995-12-01

451

Timing of malolactic fermentation inoculation in Shiraz grape must and wine: influence on chemical composition.  

PubMed

Malolactic fermentation (MLF) is an integral step in red winemaking, which in addition to deacidifying wine can also influence the composition of volatile fermentation-derived compounds with concomitant affects on wine sensory properties. Long-established winemaking protocols for MLF induction generally involve inoculation of bacteria starter cultures post alcoholic fermentation, however, more recently there has been a trend to introduce bacteria earlier in the fermentation process. For the first time, this study shows the impact of bacterial inoculation on wine quality parameters that define red wine, including wine colour and phenolics, and volatile fermentation-derived compounds. This study investigates the effects of inoculating Shiraz grape must with malolactic bacteria at various stages of alcoholic fermentation [beginning of alcoholic fermentation (co-inoculation, with yeast), mid-alcoholic fermentation, at pressing and post alcoholic fermentation] on the kinetics of MLF and wine chemical composition. Co-inoculation greatly reduced the overall fermentation time by up to 6 weeks, the rate of alcoholic fermentation was not affected by the presence of bacteria and the fermentation-derived wine volatiles profile was distinct from wines produced where bacteria were inoculated late or post alcoholic fermentation. An overall slight decrease in wine colour density observed following MLF was not influenced by the MLF inoculation regime. However, there were differences in anthocyanin and pigmented polymer composition, with co-inoculation exhibiting the most distinct profile. Differences in yeast and bacteria metabolism at various stages in fermentation are proposed as the drivers for differences in volatile chemical composition. This study demonstrates, with an in-depth analysis, that co-inoculation of yeast and bacteria in wine fermentation results in shorter total vinification time and produces sound wines, thus providing the opportunity to stabilise wines more rapidly than traditional inoculation regimes permit and thereby reducing potential for microbial spoilage. PMID:22806801

Abrahamse, Caroline E; Bartowsky, Eveline J

2011-06-23

452

Effects of fermented persimmon extract supplements on chemical composition and fermentation characteristics of barley silage.  

PubMed

This study was conducted to estimate the effect of fermented persimmon extract (FPE) supplementation levels on chemical composition and fermentation characteristics of barley silage. Barley forage was harvested at 25% dry matter and chopped to 5?cm lengths. The FPE was applied at 0, 0.4, 0.8 and 1.6?g/kg of barley forage (fresh weight basis). After sub-sampling of barley forages (0 day), a total of 64 laboratory mini silos (5?kg capacity) were ensiled to generate quadruplicate data from each of four treatments for four ensiling durations (2, 6, 40 and 120 days). The chemical compositions and in vitro digestibility of barley forage (0 day) were not affected by FPE supplementation. However, the content (L, P?=?0.035) and in vitro digestibility (L, P?=?0.041) of neutral detergent fiber on 120-day barley silage decreased by increasing FPE supplements. Acetate content of barley silage ensiled for 120 days increased (Q, P?=?0.004) by increasing FPE supplements, whereas pH (L, P?

Kim, Sang Bum; Kim, Dong Hyeon; Lee, Hyuk Jun; Amanullah, Sadar M; Kim, Sam Churl

2012-12-26

453

Cow's urine concoction: its chemical composition, pharmacological actions and mode of lethality.  

PubMed

A review of current information on the composition, pharmacological actions and mode of death from cow's urine concoction (CUC) toxicity is presented. The concoction is prepared from leaves of tobacco, garlic and basil; lemon juice, rock salt and bulbs of onion. The latter items are soaked in the urine from cows which acts as the vehicle in which the active principles in these constituents dissolve. Over fifty chemical compounds have been identified in CUC. The major compounds it contains are benzoic acid, phenylacetic acid, p-cresol, thymol and nicotine. The chemical composition and pharmacological cations of the individual components of CUC are also reviewed. Observations of CUC poisoning in man and experimental animals showed that the main effects of CUC are severe depression of respiration, cardiovascular system, the central nervous system and hypoglycaemia. These toxic effects acting singly or in combination are believed to be the cause(s) of death from CUC. Management is geared towards correcting these adverse effects. PMID:6314793

Oyebola, D D

1983-03-01

454

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

USGS Publications Warehouse

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

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

1985-01-01

455

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.

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

2010-01-01

456

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

2012-05-18

457

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

PubMed

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

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

2012-07-14

458

Chemical composition of essential oils of Litsea cubeba harvested from its distribution areas in China.  

PubMed

Litsea cubeba (Lour.) Pers. is a promising industrial crop with fruits rich in essential oils. The chemical composition of essential oils of L. cubeba (EOLC) were determined for fruits harvested from eight regions in China. The overall essential oil content, obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), ranged from 3.04% to 4.56%. In total, 59 compounds were identified, the dominant components being monoterpenes (94.4-98.4%), represented mainly by neral and geranial (78.7-87.4%). D-Limonene was unexpectedly a lesser constituent (0.7-5.3%) in fruits, which differed from previous reports (6.0-14.6%). Several components were only detected in certain regions and compounds such as o-cymene and eremophilene have never before been reported in EOLC. These results demonstrate significant regional variation in the chemical composition of EOLC. This investigation provides important information with regard to the bioactivity, breeding work and industrial applications of L. cubeba. PMID:22683894

Si, Linlin; Chen, Yicun; Han, Xiaojiao; Zhan, Zhiyong; Tian, Shengping; Cui, Qinqin; Wang, Yangdong

2012-06-08

459

Mechano-Chemical Preparation of Powder QUARTZ/TiO2 Composite Particles  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

460

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.

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

2005-01-01

461

CHEMICAL PACEMAKERS  

PubMed Central

1. Iron spicules found in the brains of general paretic patients are formed from endogenous brain iron normally present in another form. This supports our earlier view that the µ value of 16,000 obtained in advanced paretics for alpha brain wave frequencies as a measure of cortical respiration comes about from the slowing of an iron catalyzed link in cortical respiration such as would result from the reduction of available cytochrome and its oxidase, thus making this step a chemical pacemaker. 2. To test the basic theory of chemical pacemakers, a study was made of the succinate-fumarate enzyme system containing succino-dehydrogenase and cytochrome-cytochrome oxidase acting sequentially. 3. The µ value for the unpoisoned system is 11,200 ± 200 calories. 4. According to theory, the addition of a critical amount of cyanide known to be a specific poison of the cytochrome-cytochrome oxidase system (and not of the dehydrogenase) should shift the µ cleanly to 16,000 calories, and it does. 5. According to theory, selenite, a specific poison for the dehydrogenase, should stop all respiration without shifting the µ. This also is found to be the case. 6. The theory also predicts that if the µ is shifted from 11,000 ± to 16,000 ± by cyanide, the subsequent addition of a critical amount of selenite should shift the µ back again to 11,000 ± calories, and this is found to occur. 7. It is concluded that approximately 11,000 calories is the energy of activation of the succino-dehydrogenase-catalyzed step and 16,000 calories is that for the cytochrome-cytochrome oxidase-catalyzed step. These two values are encountered more frequently than any others in physiological systems. It is to be recalled that a shift of µ for alpha brain wave frequencies from 11,000 to 16,000 calories occurs in the course of advancing syphilitic brain infection and is accompanied by a change in form of brain iron.

Hadidian, Zareh; Hoagland, Hudson