WorldWideScience

Sample records for chemical composition impact

  1. Impact of oil on groundwater chemical composition

    Science.gov (United States)

    Brakorenko, N. N.

    2015-11-01

    The objective of the paper is to characterize the chemical composition of groundwater samples from the monitoring wells drilled in the petrol station areas within the vicinity of Tomsk. The level of contamination has increased since many macro - and microcomponent concentrations (such as petroleum products, chlorine, sulphates, carbon dioxide and lead, etc.) in groundwater samples of the present study is higher than that in previous period samples.

  2. Areca Fiber Reinforced Epoxy Composites: Effect of Chemical Treatments on Impact Strength

    Directory of Open Access Journals (Sweden)

    S. Dhanalakshmi

    2015-06-01

    Full Text Available In this research work, impact strength of untreated, alkali treated, potassium permanganate treated, benzoyl chloride treated and acrylic acid treated areca fiber reinforced epoxy composites were studied under 40%, 50%, 60% and 70% fiber loadings. Impact strength increased with increase in fiber loading up to 60% and then showed a decline for all untreated and chemically treated areca fiber reinforced epoxy composites. The acrylic acid treated areca fiber reinforced epoxy composites with 60% fiber loading showed highest impact strength of 28.28 J/mm2 amongst all untreated and chemically treated areca/epoxy composites with same 60% fiber loading.

  3. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests

    Science.gov (United States)

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y. H.

    2016-07-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon’s index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems.

  4. Low temperature impact strength of heavy section ductile iron castings: effects of microstructure and chemical composition

    Directory of Open Access Journals (Sweden)

    C. Labrecque

    2011-02-01

    Full Text Available A foundry research project has been recently initiated at RTIT in order to better understand the fabrication of as-cast heavy section DI parts meeting high impact energy requirements at low temperatures. The experimental castings have the following dimensions 180 mm x 180 mm x 190 mm. The achieved as-cast Charpy impact strengths were as follows: 17 J (RT, 16 J (-20°C and 11 J (-40°C. The foundry process, the chemical composition and the microstructure of this experimental casting are compared to the ones of various examples in order to show the detrimental effects of residual elements, microshrinkage and microcarbide on the impact properties. Finally, quality index empirical models (based on casting chemical compositions are used to analyse the impact tests results. This paper illustrates that an adequate nodule count can contribute to reducing the detrimental effects of the residual elements and microsegregation.

  5. Biomass burning aerosol over the Amazon during SAMBBA: impact of chemical composition on radiative properties

    Science.gov (United States)

    Morgan, William; Allan, James; Flynn, Michael; Darbyshire, Eoghan; Hodgson, Amy; Liu, Dantong; O'shea, Sebastian; Bauguitte, Stephane; Szpek, Kate; Langridge, Justin; Johnson, Ben; Haywood, Jim; Longo, Karla; Artaxo, Paulo; Coe, Hugh

    2014-05-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect but with the uncertainty being 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, both in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated

  6. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    CERN Document Server

    Zellner, N E B

    2015-01-01

    Lunar impact glasses, quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. Based on the relationships presented in this paper, lunar impact glasses with compositions and sizes sufficient to have retained 90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integra...

  7. Wildfire Ash: Chemical Composition, Ash-Soil Interactions and Environmental Impacts

    Science.gov (United States)

    Brook, Anna; Hamzi, Seham; Wittenberg, Lea

    2015-04-01

    produced ash has significant and not always constructive pedological, ecological, hydrological and geomorphological effects and impacts (Shakesby, 2011). Abundant scientific information is assembled either from control fires by collecting samples before and after wildfire event, or conducting laboratory experiments exanimating data under truly isolated conditions (Lugassi et al., 2013). However, an integration and synthesis of the knowledge about ash including deeper understanding of inter-correlation between chemical, physical and morphological compounds in open post-burn environment and its possible interactions in soil formation or impact on soil composition are highly needed. The main aim of the presented study was to advance the science of soil-fire relationship by recognizing the remains ash as a new soil-forming factor, on par with the traditionally recognized factors: parent material, topography, time, climate, organisms, and recently recognized human activity as the sixth factor. This research was conducted to develop new methods to assess impacts and quantify the contributions/influences of post-fire products, mainly ash, on soil composition and soil properties in post-burned environment. We conducted several controlled experiments using 40 soil samples (typical Mediterranean Rendzina soil, pH 6.84, a grayish-brown, humus- and free calcium carbonate- rich, intra-zonal). The samples include bare soils and different types and loads of forest litter, were exposed to different temperatures (200° C, 400° C and 600° C) in a muffle furnace for 2 hours (Pereira et al. 2011) as fire temperature plays a key role in determining ash properties. The ash produced at a low temperatures (50% carbon and retains many of the structural characteristics of the parent material. At higher temperatures, the residue ash is greyish, consisted of very fine particles that preserve almost none of the original structural characteristics of the fuel (Woods and Balfour, 2008) creating

  8. Chemical composition of fennel essential oil and its impact on Staphylococcus aureus exotoxin production.

    Science.gov (United States)

    Qiu, Jiazhang; Li, Hongen; Su, Hongwei; Dong, Jing; Luo, Mingjing; Wang, Jianfeng; Leng, Bingfeng; Deng, Yanhong; Liu, Juxiong; Deng, Xuming

    2012-04-01

    In this study, fennel oil was isolated by hydrodistillation, and the chemical composition was determined by gas chromatography/mass spectral analysis. The antimicrobial activity of fennel oil against Staphylococcus aureus was evaluated by broth microdilution. A haemolysis assay, tumour necrosis factor (TNF) release assay, western blot, and real-time reverse transcription (RT)-PCR were applied to investigate the influence of fennel oil on the production of S. aureus virulence-related exoproteins. The data show that fennel oil, which contains a high level of trans-anethole, was active against S. aureus, with MICs ranging from 64 to 256 μg/ml. Furthermore, fennel oil, when used at subinhibitory concentrations, could dose-dependently decrease the expression of S. aureus exotoxins, including α-toxin, Staphylococcal enterotoxins (SEs) and toxic shock syndrome toxin 1 (TSST-1).

  9. Flood pulse influence and anthropic impact on the chemical composition and energy content of Oryza glumaepatula in an Amazonian lake.

    Science.gov (United States)

    Enrich-Prast, A; Esteves, F A

    2005-08-01

    The aim of this research was to study the flood pulse influence and the anthropic impact caused by bauxite tailings on the chemical composition of O. glumaepatula in Batata lake (PA, Brazil). Sampling was carried out in stands of O. glumaepatula in the low-water, filling, high-water, and drawdown periods in impacted and natural areas of Batata lake. During the low-water and drawdown periods the stands of O. glumaepatula were exposed, and in the filling and high-water periods the water depth was respectively 1.4 and 3.8 m. The collected material was dried at 70 degrees C, ground, and concentrations of total phosphorus, total nitrogen, organic carbon, and energy content were determined. The results indicate that the biomass increase, caused by the rise in water level, has a dilution effect on nitrogen and phosphorus concentrations in O. glumaepatula. The energy contents did not present significant differences in any of the studied periods. The results suggest that from the low water to filling period, nitrogen becomes more limiting to O. glumaepatula in the impacted area, whereas phosphorus becomes more limiting in the natural area. The population of O. glumaepatula contributes to the recovery of the impacted area of Batata lake as the detritus from this species accumulates over the sediment. This accumulation impedes future re-suspension of the bauxite tailings and increases the organic matter and nutrient concentrations in the impacted sediment.

  10. Chemical recycling of scrap composites

    Science.gov (United States)

    Allred, Ronald E.; Salas, Richard M.

    1994-01-01

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

  11. Impact of Dissolved Oxygen during UV-Irradiation on the Chemical Composition and Function of CHO Cell Culture Media.

    Directory of Open Access Journals (Sweden)

    Sarah M Meunier

    Full Text Available Ultraviolet (UV irradiation is advantageous as a sterilization technique in the biopharmaceutical industry since it is capable of targeting non-enveloped viruses that are typically challenging to destroy, as well as smaller viruses that can be difficult to remove via conventional separation techniques. In this work, we investigated the influence of oxygen in the media during UV irradiation and characterized the effect on chemical composition using NMR and LC-MS, as well as the ability of the irradiated media to support cell culture. Chemically defined Chinese hamster ovary cell growth media was irradiated at high fluences in a continuous-flow UV reactor. UV-irradiation caused the depletion of pyridoxamine, pyridoxine, pyruvate, riboflavin, tryptophan, and tyrosine; and accumulation of acetate, formate, kynurenine, lumichrome, and sarcosine. Pyridoxamine was the only compound to undergo complete degradation within the fluences considered; complete depletion of pyridoxamine was observed at 200 mJ/cm2. Although in both oxygen- and nitrogen-saturated media, the cell culture performance was affected at fluences above 200 mJ/cm2, there was less of an impact on cell culture performance in the nitrogen-saturated media. Based on these results, minimization of oxygen in cell culture media prior to UV treatment is recommended to minimize the negative impact on sensitive media.

  12. Modeling the Changing Chemical Composition of the Atmosphere: Impacts from the Stratosphere, Transport Modes and Climate Variability

    Science.gov (United States)

    Grewe, V.; Obermaier, K.; Ponater, M.; Matthes, S.

    2008-12-01

    The chemical composition of the atmosphere is permanently changing, driven by changes in emissions (natural and anthropogenic) as well as natural climate variability (e.g. El Nino, stratospheric variability). Here, an ensemble climate chemistry simulation for the period 1960 to 2020 is presented in which stratospheric and tropospheric chemistry are regarded consistently (Dameris et al., 2005; Grewe, 2007). Changes in chemistry and radiative forcing are analysed in detail. The results show: a reduced tropospheric ozone increase in the 90s caused by a decrease of stratospheric ozone influxes due to stratospheric ozone depletion. a reduced tropospheric ozone column in the equatorial pacific region due to El Nino (in agreement with observations), however an increase in lightning and related tropospheric ozone. a peak in ozone production efficiency due to NOx emission in around 1990 decrease in lightning NOx emissions over the whole period due to less (though stronger) convective events. differences between the radiative efficiency of tropospheric ozone changes contributed by individual sources changes of the radiative efficiency of the same source throughout the 60-yr period Grewe, V., Impact of climate variability on tropospheric ozone, Science of The Total Environment, 374, 167- 181, 2007. Dameris, M., Grewe, V., Ponater, M., "., Long-term changes and variability in a transient simulation with a chemistry-climate model employing realistic forcing, ACP 5, 2121-2145, 2005.

  13. Impact of chemical treatments on the mechanical and water absorption properties of coconut fibre (Cocos nucifera reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    Isiaka O. OLADELE

    2016-07-01

    Full Text Available In this work, chemically treated coconut fibres were used to reinforce Homopolymer Polypropylene in order to ascertain the effect of the treatments on the mechanical and water absorption properties of the composites produced. Coconut fibre was first extracted from its husk by soaking it in water and was dried before it was cut into 10 mm lengths. It was then chemically treated in alkali solution of sodium hydroxide (NaOH and potassium hydroxide (KOH in a shaker water bath. The treated coconut fibres were used as reinforcements in polypropylene matrix to produce composites of varied fibre weight contents; 2, 4, 6, 8 and 10 wt.%. Tensile and flexural properties were investigated using universal testing machine while water absorption test was carried out on the samples for 7 days. It was observed from the results that, NaOH treated samples gave the best tensile properties while KOH treated samples gave the best flexural and water repellent properties.

  14. Impact of chabazite SSZ-13 textural properties and chemical composition on CO 2 adsorption applications

    Energy Technology Data Exchange (ETDEWEB)

    Prodinger, Sebastian; Vemuri, Rama S.; Varga, Tamas; Peter McGrail, B.; Motkuri, Radha Kishan; Derewinski, Miroslaw A.

    2016-01-01

    Chabazite SSZ-13 samples with varying silica content (Si/Al from 6 to 35) were synthesized in both stirring and static conditions to obtain material with changing particle size and morphology and thoroughly analysed with various characterization techniques. The role of particle size and chemical compositions of SSZ-13 chabazite on CO2 and N2 adsorption measurements was investigated. The Si/Al ratio played a major role for CO2 adsorption with Al-rich SSZ-13 showing a higher CO2 uptake than Al-poor material. This was attributed to the high density of active charged species in the chabazite cage. Particle size also played an important role in the sorption capacities with smaller particles, obtained in stirring conditions, showing enhanced CO2 uptakes compared to larger particles of same chemical composition. This was associated with an increased density of surface active sites and shorter diffusion pathways.

  15. Method of forming a chemical composition

    Science.gov (United States)

    Bingham, Dennis N.; Wilding, Bruce M.; Klingler, Kerry M.; Zollinger, William T.; Wendt, Kraig M.

    2007-10-09

    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.

  16. The Impact of the South Asia High Bimodality on the Chemical Composition of the Upper Troposphere and Lower Stratosphere

    Institute of Scientific and Technical Information of China (English)

    YAN Ren-Chang; BIAN Jian-Chun; FAN Qiu-Jun

    2011-01-01

    The South Asia High (SAH) is the dominant feature of the circulation in the upper troposphere and lower stratosphere (UTLS) during the boreal summer, and the upper tropospheric anticyclonic circulation extends into the lower stratosphere. The preferred locations of the center of the SAH occur in two different regions, and the center can be located over the Iranian Plateau or over the Tibetan Plateau. This bimodality has an impact on the distribution of chemical constituents in the UTLS region. We analyzed water vapor (H20), carbon monoxide (CO), and ozone (03) data derived from the Aura Microwave Limb Sounder (MLS) and total column ozone data from the Ozone Monitoring Instrument (OMI). For the Iranian Plateau mode of the SAH, the tropospheric tracers exhibited a positive anomaly over the Iranian Plateau and a negative anomaly over the Tibetan Plateau, whereas the stratospheric tracer exhibited a negative and a positive anomaly over the Iranian Plateau and the Tibetan Plateau, respectively. For the Tibetan Plateau mode, however, the distribution of the anomaly was the reverse of that found for the chemical species in the UTLS region. Furthermore, the locations of the extrema within the anomaly seemed to differ across chemical species. The anomaly extrema for H20 occurred in the vicinity of the SAH ridgeline, whereas CO and O3 exhibited a northward shift of 4-8 degrees. These impacts of the variation in the SAH on the chemical constitutes in the UTLS region can be attributed in part to the dynamical structure delineated by the tropopause field and the temperature field at 100 hPa.

  17. [Chemical Compositions in PM2.5 and Its Impact on Visibility in Summer in Pearl River Delta, China].

    Science.gov (United States)

    Yang, Yi-hong; Qu, Qun; Liu, Sui-xin; Li, Xiong; Zhong, Pei-yi; Tau, Jun

    2015-08-01

    Aerosol samples of PM2.5 were collected simultaneously at 6 sites from five cities (Guangzhou urban, Conghua (suburban of Guangzhou), Foshan, Dongguan, Shenzhen and Zhubai) in Pearl River Delta region during the summer of 2010. The concentrations of organic carbon (OC), elemental carbon (EC) and water-soluble ions were determined by thermal/optical carbon analyzer and ion chromatography, respectively. The characteristics of PM2, OC, EC and ions, spatial distribution were discussed. Moreover, ambient light extinction coefficients were reconstructed by IMPROVE formula. The results showed that spatial distribution characteristics of PM2.5. and its chemical compositions were obviously different. The PM2.5 in Guangzhou, Foshan and Dongguan were higher than those in Zhuhai and Shenzhen. The contributions of (NH4)2SO4, OM, EC and NH4NO3 to ambient light extinction coefficient were 39%, 31%, 12% and 13%, respectively.

  18. The Chemical Composition of Honey

    Science.gov (United States)

    Ball, David W.

    2007-01-01

    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…

  19. The chemical composition of ultrafine particles and associated biological effects at an alpine town impacted by wood burning.

    Science.gov (United States)

    Corsini, Emanuela; Vecchi, Roberta; Marabini, Laura; Fermo, Paola; Becagli, Silvia; Bernardoni, Vera; Caruso, Donatella; Corbella, Lorenza; Dell'Acqua, Manuela; Galli, Corrado L; Lonati, Giovanni; Ozgen, Senem; Papale, Angela; Signorini, Stefano; Tardivo, Ruggero; Valli, Gianluigi; Marinovich, Marina

    2017-02-25

    This work is part of the TOBICUP (TOxicity of BIomass Combustion generated Ultrafine Particles) project which aimed at providing the composition of ultrafine particles (UFPs, i.e. particles with aerodynamic diameter, dae, lower than 100nm) emitted by wood combustion and elucidating the related toxicity. Results here reported are from two ambient monitoring campaigns carried out at an alpine town in Northern Italy, where wood burning is largely diffused for domestic heating in winter. Wintertime and summertime UFP samples were analyzed to assess their chemical composition (i.e. elements, ions, total carbon, anhydrosugars, and polycyclic aromatic hydrocarbons) and biological activity. The induction of the pro-inflammatory cytokine interleukin-8 (IL-8) by UFPs was investigated in two human cells lines (A549 and THP-1) and in human peripheral blood leukocytes. In addition, UFP-induced oxidative stress and genotoxicity were investigated in A549 cells. Ambient UFP-related effects were compared to those induced by traffic-emitted particles (DEP) taken from the NIES reference material "vehicle exhaust particulates". Ambient air UFPs induced a dose-related IL-8 release in both A549 and THP-1 cells; the effect was more relevant on summer samples and in general THP-1 cells were more sensitive than A549 cells. On a weight basis our data did not support a higher biological activity of ambient UFPs compared to DEP. The production of IL-8 in the whole blood assay indicated that UFPs reached systemic circulation and activated blood leukocytes. Comet assay and γ-H2AX evaluation showed a significant DNA damage especially in winter UFPs samples compared to control samples. Our study showed that ambient UFPs can evoke a pulmonary inflammatory response by inducing a dose-related IL-8 production and DNA damage, with different responses to UFP samples collected in the summer and winter periods.

  20. Major impact of volcanic gases on the chemical composition of precipitation in Iceland during the 2014-2015 Holuhraun eruption

    Science.gov (United States)

    Stefánsson, Andri; Stefánsson, Gerdur; Keller, Nicole S.; Barsotti, Sara; Sigurdsson, Árni; Thorláksdóttir, Svava Björk; Pfeffer, Melissa Anne; Eiríksdóttir, Eydís. S.; Jónasdóttir, Elín. Björk; Löwis, Sibylle; Gíslason, Sigurdur R.

    2017-02-01

    The Holuhraun eruption in 2014-2015 was the largest in Iceland for more than 200 years. It resulted in emissions of large quantities of volcanic gases into the atmosphere (11 megaton (Mt) SO2, 0.1 Mt HCl, and 0.05 Mt HF). During the eruption the volcanic gases had major effects on F, SO4 and to a lesser extent Cl concentrations in precipitaxtion throughout Iceland, effects not observed in recent decades. The concentrations of F, Cl, and SO4 (n = 705) reached values of 444 µm 12,270 µm, and 17,324 µm during the eruption and were on average 20 times higher for F and SO4 and much lower for Cl compared to preeruption times. The concentrations of major cations (Si, Na, K, Ca, Mg, Al, and Fe) (n = 151) in the precipitation were taken as having originated from seawater spray and dissolution of rock dust and aerosol. Based on the mixing model developed here, it is demonstrated that the source of the enrichment of F and SO4 was indeed the volcanic gas emissions with >60-100 mol % of SO4 and F in the precipitation originated from volcanic gas, whereas the Cl originated mostly from seawater spray, making the volcanic gas input of Cl relatively less important than for F and SO4. The results showed that large volcanic eruptions can have major effects on atmospheric chemistry and impact the composition of precipitation.

  1. Chemical composition of PM10 and its in vitro toxicological impacts on lung cells during the Middle Eastern Dust (MED) storms in Ahvaz, Iran.

    Science.gov (United States)

    Naimabadi, Abolfazl; Ghadiri, Ata; Idani, Esmaeil; Babaei, Ali Akbar; Alavi, Nadali; Shirmardi, Mohammad; Khodadadi, Ali; Marzouni, Mohammad Bagherian; Ankali, Kambiz Ahmadi; Rouhizadeh, Ahmad; Goudarzi, Gholamreza

    2016-04-01

    Reports on the effects of PM10 from dust storm on lung cells are limited. The main purpose of this study was to investigate the chemical composition and in vitro toxicological impacts of PM10 suspensions, its water-soluble fraction, and the solvent-extractable organics extracted from Middle Eastern Dust storms on the human lung epithelial cell (A549). Samples of dust storms and normal days (PM10 Iran. The chemical composition and cytotoxicity were analyzed by ICP- OES and Lactase Dehydrogenase (LDH) reduction assay, respectively. The results showed that PM10 suspensions, their water-soluble fraction and solvent-extractable organics from both dust storm and normal days caused a decrease in the cell viability and an increase in LDH in supernatant in a dose-response manner. Although samples of normal days showed higher cytotoxicity than those of dust storm at the highest treated dosage, T Test showed no significant difference in cytotoxicity between normal days and dust event days (P value > 0.05). These results led to the conclusions that dust storm PM10 as well as normal day PM10 could lead to cytotoxicity, and the organic compounds (PAHs) and the insoluble particle-core might be the main contributors to cytotoxicity. Our results showed that cytotoxicity and the risk of PM10 to human lung may be more severe during dust storm than normal days due to inhalation of a higher mass concentration of airborne particles. Further research on PM dangerous fractions and the most responsible components to make cytotoxicity in exposed cells is recommended.

  2. Chemical composition of interstellar dust

    Science.gov (United States)

    Das, Ankan; Chakrabarti, Sandip Kumar; Majumdar, Liton; Sahu, Dipen

    physical parameters of interstellar medium (ISM). To mimic exact interstellar condition, gas grain interactions via accretion from gas phase and desorption (thermal evaporation, photo-evaporation and non-thermal evaporation) from grain surface are considered. We find that chemical composition of interstellar grain mantle is highly dependent on physical parameters associated with a molecular cloud. Interstellar photons are seen to play an important role towards growth and structure of interstellar grain mantle. We consider effects of interstellar photons (photo-dissociation and photo-evaporation) in our simulation under various interstellar circumstances.

  3. Insights into a dust event transported through Beijing in spring 2012: Morphology, chemical composition and impact on surface aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Wei [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502 (Japan); Niu, Hongya [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Key Laboratory of Resource Exploration Research of Hebei Province, Hebei University of Engineering, Handan, Hebei 056038 (China); Zhang, Daizhou [Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502 (Japan); Wu, Zhijun [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Chen, Chen [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Beijing Municipal Environmental Monitoring Center, Beijing 100044 (China); Wu, Yusheng; Shang, Dongjie [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China); Hu, Min, E-mail: minhu@pku.edu.cn [State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871 (China)

    2016-09-15

    Multiple approaches were used to investigate the evolution of surface aerosols in Beijing during the passage of a dust event at high altitude, which was from the Gobi areas of southern Mongolia and covered a wide range of North China. Single particle analysis with electron microscope showed that the majority of coarse particles were mineral ones, and most of them were in the size range of 1–7 μm with a peak of number concentration at about 3.5 μm. Based on elemental composition and morphology, the mineral particles could be classified into several groups, including Si-rich (71%), Ca-rich (15%), Fe-rich (6%), and halite-rich (2%), etc., and they were the main contributors to the aerosol optical depth as the dust occurred. The size distributions of surface aerosols were significantly affected by the dust intrusion. The average number concentration of accumulation mode particles during the event was about 400 cm{sup −3}, which was much lower than that in heavily polluted days (6300 cm{sup −3}). At the stage of floating dust, the number concentration of accumulation mode particles decreased, and coarse particles contributed to total volume concentration of particulate matter as much as 90%. The accumulation mode particles collected in this stage were mostly in the size range of 0.2–0.5 μm, and were rectangular or spherical. They were considered to be particles consisting of ammonium sulfate. New particle formation (NPF) was observed around noon in the three days during the dust event, indicating that the passage of the dust was probably favorable for NPF. - Highlights: • A dust event transported at high altitude through Beijing was investigated. • The dust event caused high variation in surface aerosol number concentrations. • Fine particles in the floating dust period probably consisted of ammonium sulfate. • Passage of the dust induced a favorable condition for new particle formation.

  4. Graphene composites containing chemically bonded metal oxides

    Indian Academy of Sciences (India)

    K Pramoda; S Suresh; H S S Ramakrishna Matte; A Govindaraj

    2013-08-01

    Composites of graphene involving chemically bonded nano films of metal oxides have been prepared by reacting graphene containing surface oxygen functionalities with metal halide vapours followed by exposure to water vapour. The composites have been characterized by electron microscopy, atomic force microscopy and other techniques. Magnetite particles chemically bonded to graphene dispersible in various solvents have been prepared and they exhibit fairly high magnetization.

  5. Chemical composition of Earth-like planets

    CERN Document Server

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

    2015-01-01

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

  6. Impact of melt migration on the evolution of major and trace element composition in a crystalline mush: Implications for chemical differentiation in the continental crust

    Science.gov (United States)

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

    2013-12-01

    Migration of melt through a crystalline mush is common within the continental crust, occurring in magma chambers and lava flows. Mush formation and associated migration of the buoyant melt along grain boundaries is inevitable during melting of initially solid rock, or cooling and crystallisation of magma. Because there is efficient exchange of heat and mass between melt and solid phases, they remain in local thermal and chemical equilibrium. The composition of the melt therefore evolves as it migrates through the mush and, to properly capture this, models are required that include chemical reaction. However, although reactive transport models have been developed for the mantle, none have yet been presented that are applicable to the continental crust. Models developed for the mantle are not directly applicable to the crust, because the initial and boundary conditions are different. We present the first quantitative model of heat, mass and both major and trace element transport in a mush undergoing compaction which accounts for component transport and chemical reaction during melt migration and which is applicable to crustal systems. The model describes the phase behaviour of binary systems (both eutectic and solid solution), with melt and solid composition determined from phase diagrams using the local temperature and bulk composition. Trace element concentration is also determined. The results demonstrate that component transport and chemical reaction generates compositional variation in both major and trace elements that is not captured by existing geochemical models. Even for the simplest case of a homogenous, insulated column that is instantaneously melted then allowed to compact, we find that component transport and reaction leads to spatial variations in major element composition, and produces melt that is more enriched in incompatible elements than predicted by batch melting. In deep crustal hot zones (DCHZ), created by the repeated intrusion of hot, mantle

  7. Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

    Science.gov (United States)

    Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

  8. Chemical composition of Achatina fulica

    Directory of Open Access Journals (Sweden)

    Aboua, F.

    1990-01-01

    Full Text Available Proximate composition and mineral content were determined in snail without and with shell and shell atone from Achatina fulica. This snail has high protein (above 40 %, low fat (less than 3 % and is a relatively good source of macrominerals, including calcium, phosphorus, magnesium, potassium and sodium. Achatina fulica is an excellent source of iron but is poor in copper, zinc and manganese. The snail is very rich in calcium but very poor in phosphorus, potassium and magnesium.

  9. Binary stars: Mass transfer and chemical composition

    Science.gov (United States)

    Lambert, D. L.

    1982-01-01

    It is noted that mass exchange (and mass loss) within a binary system should produce observable changes in the surface chemical composition of both the mass losing and mass gaining stars as a stellar interior exposed to nucleosyntheses is uncovered. Three topics relating mass exchange and/or mass loss to nucleosynthesis are sketched: the chemical composition of Algol systems; the accretion disk of a cataclysmic variable fed by mass from a dwarf secondary star; and the hypothesis that classical Ba II giants result from mass transfer from a more evolved companion now present as a white dwarf.

  10. Impact resistance of fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1982-01-01

    Stress-strain curves are obtained for a variety of glass fiber and carbon fiber reinforced plastics in dynamic tension, over the stress-strain range of 0.00087-2070/sec. The test method is of the one-bar block-to-bar type, using a rotating disk or a pendulum as the loading apparatus and yielding accurate stress-strain curves up to the breaking strain. In the case of glass fiber reinforced plastic, the tensile strength, strain to peak impact stress, total strain and total absorbed energy all increase significantly as the strain rate increases. By contrast, carbon fiber reinforced plastics show lower rates of increase with strain rate. It is recommended that hybrid composites incorporating the high strength and rigidity of carbon fiber reinforced plastic with the high impact absorption of glass fiber reinforced plastics be developed for use in structures subjected to impact loading.

  11. Chemical Composition and Potential Environmental Impacts of Water-Soluble Polar Crude Oil Components Inferred from ESI FT-ICR MS.

    Science.gov (United States)

    Liu, Yina; Kujawinski, Elizabeth B

    2015-01-01

    Polar petroleum components enter marine environments through oil spills and natural seepages each year. Lately, they are receiving increased attention due to their potential toxicity to marine organisms and persistence in the environment. We conducted a laboratory experiment and employed state-of-the-art Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to characterize the polar petroleum components within two operationally-defined seawater fractions: the water-soluble fraction (WSF), which includes only water-soluble molecules, and the water-accommodated fraction (WAF), which includes WSF and microscopic oil droplets. Our results show that compounds with higher heteroatom (N, S, O) to carbon ratios (NSO:C) than the parent oil were selectively partitioned into seawater in both fractions, reflecting the influence of polarity on aqueous solubility. WAF and WSF were compositionally distinct, with unique distributions of compounds across a range of hydrophobicity. These compositional differences will likely result in disparate impacts on environmental health and organismal toxicity, and thus highlight the need to distinguish between these often-interchangeable terminologies in toxicology studies. We use an empirical model to estimate hydrophobicity character for individual molecules within these complex mixtures and provide an estimate of the potential environmental impacts of different crude oil components.

  12. Chemical Composition and Potential Environmental Impacts of Water-Soluble Polar Crude Oil Components Inferred from ESI FT-ICR MS.

    Directory of Open Access Journals (Sweden)

    Yina Liu

    Full Text Available Polar petroleum components enter marine environments through oil spills and natural seepages each year. Lately, they are receiving increased attention due to their potential toxicity to marine organisms and persistence in the environment. We conducted a laboratory experiment and employed state-of-the-art Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS to characterize the polar petroleum components within two operationally-defined seawater fractions: the water-soluble fraction (WSF, which includes only water-soluble molecules, and the water-accommodated fraction (WAF, which includes WSF and microscopic oil droplets. Our results show that compounds with higher heteroatom (N, S, O to carbon ratios (NSO:C than the parent oil were selectively partitioned into seawater in both fractions, reflecting the influence of polarity on aqueous solubility. WAF and WSF were compositionally distinct, with unique distributions of compounds across a range of hydrophobicity. These compositional differences will likely result in disparate impacts on environmental health and organismal toxicity, and thus highlight the need to distinguish between these often-interchangeable terminologies in toxicology studies. We use an empirical model to estimate hydrophobicity character for individual molecules within these complex mixtures and provide an estimate of the potential environmental impacts of different crude oil components.

  13. Chemical composition of selected Saudi medicinal plants

    Directory of Open Access Journals (Sweden)

    Ihsanullah Daur

    2015-05-01

    Full Text Available Medicinal plants are important in traditional medicine and modern pharmaceutical drugs; therefore, the interest in the analysis of their chemical composition is increasing. In this study, selected medicinal plants including Achillea fragrantissima (Forssk Sch., Amaranthus viridis L., Asteriscus graveolens (Forssk. Less., Chenopodium album L., and Conyza bonariensis (L. Cronquist were collected from the rangeland of western regions (Bahra and Hada areas of Saudi Arabia to study their chemical composition. Eight minerals (Mg, Ca, Cr, Mn, Fe, Co, Cu, and Zn, total phenolic contents, antioxidant activity, and free-radical scavenging ability were examined in order to evaluate the medicinal potential of these plants. All the plants were found to be rich sources of minerals and antioxidants, although there were significant differences (p < 0.05 in their chemical composition, which may provide a rationale for generating custom extracts from specific plants depending on the application. The findings of this study will thus facilitate herbalists in their efforts to incorporate these plants into various formulations based on their chemical composition.

  14. [Investigation of chemical composition of propolis extract].

    Science.gov (United States)

    Majiene, Daiva; Trumbeckaite, Sonata; Grūnoviene, Danguole; Ivanauskas, Liudas; Gendrolis, Antanas

    2004-01-01

    Propolis is a natural product, produced by bees and containing exudates from plants, mixed with bee wax. Propolis and its ethanolic extract are usually used for treatment and prevention of different diseases. Propolis has antibacterial, antiviral, antifungal, anti-inflammatory, anesthetic and immunomodulating properties. Till now there is no data about chemical composition of Lithuanian propolis. Thus, the aim of our work was to investigate the chemical composition of Lithuanian propolis and its ethanolic extract by using gas chromatography / mass spectrometry. We found, that the main structural types of compounds were terpenoids, aromatic and aliphatic acid esters. The most of terpenoids were mono- and sesquiterpens: azulene, alpha-bisabolol, citral, valerenol, etc. Thus, our data show, that the composition of propolis is various and depends on the origin of plants, from where propolis was collected.

  15. Toward a chemical reanalysis in a coupled chemistry-climate model: An evaluation of MOPITT CO assimilation and its impact on tropospheric composition

    Science.gov (United States)

    Gaubert, B.; Arellano, A. F.; Barré, J.; Worden, H. M.; Emmons, L. K.; Tilmes, S.; Buchholz, R. R.; Vitt, F.; Raeder, K.; Collins, N.; Anderson, J. L.; Wiedinmyer, C.; Martinez Alonso, S.; Edwards, D. P.; Andreae, M. O.; Hannigan, J. W.; Petri, C.; Strong, K.; Jones, N.

    2016-06-01

    We examine in detail a 1 year global reanalysis of carbon monoxide (CO) that is based on joint assimilation of conventional meteorological observations and Measurement of Pollution in The Troposphere (MOPITT) multispectral CO retrievals in the Community Earth System Model (CESM). Our focus is to assess the impact to the chemical system when CO distribution is constrained in a coupled full chemistry-climate model like CESM. To do this, we first evaluate the joint reanalysis (MOPITT Reanalysis) against four sets of independent observations and compare its performance against a reanalysis with no MOPITT assimilation (Control Run). We then investigate the CO burden and chemical response with the aid of tagged sectoral CO tracers. We estimate the total tropospheric CO burden in 2002 (from ensemble mean and spread) to be 371 ± 12% Tg for MOPITT Reanalysis and 291 ± 9% Tg for Control Run. Our multispecies analysis of this difference suggests that (a) direct emissions of CO and hydrocarbons are too low in the inventory used in this study and (b) chemical oxidation, transport, and deposition processes are not accurately and consistently represented in the model. Increases in CO led to net reduction of OH and subsequent longer lifetime of CH4 (Control Run: 8.7 years versus MOPITT Reanalysis: 9.3 years). Yet at the same time, this increase led to 5-10% enhancement of Northern Hemisphere O3 and overall photochemical activity via HOx recycling. Such nonlinear effects further complicate the attribution to uncertainties in direct emissions alone. This has implications to chemistry-climate modeling and inversion studies of longer-lived species.

  16. Impact of the chemical composition of poly-substituted hydroxyapatite particles on the in vitro pro-inflammatory response of macrophages.

    Science.gov (United States)

    Douard, Nathalie; Leclerc, Lara; Sarry, Gwendoline; Bin, Valérie; Marchat, David; Forest, Valérie; Pourchez, Jérémie

    2016-04-01

    To improve the biological properties of calcium phosphate (CaP) bone substitute, new chemical compositions are under development. In vivo such materials are subject to degradation that could lead to particles release and inflammatory reactions detrimental to the bone healing process. This study aimed at investigating the interactions between a murine macrophage cell line (RAW 264.7) and substituted hydroxyapatite particles presenting promising biological properties. Micron size particles of stoichiometric and substituted hydroxyapatites (CO3 substitution for PO4 and OH; SiO4 substitution for PO4; CO3 and SiO4 co-substitution) were obtained by aqueous precipitation followed by spray drying. Cells, incubated with four doses of particles ranging from 15 to 120 μg/mL, revealed no significant LDH release or ROS production, indicating no apparent cytotoxicity and no oxidative stress. TNF-α production was independent of the chemistry of the particles; however the particles elicited a significant dose-dependent pro-inflammatory response. As micron size particles of these hydroxyapatites could be at the origin of inflammation, attention must be paid to the degradation behavior of substituted hydroxyapatite bone substitute in order to limit, in vivo, the generation of particulate debris.

  17. In Chemico Evaluation of Tea Tree Essential Oils as Skin Sensitizers: Impact of the Chemical Composition on Aging and Generation of Reactive Species.

    Science.gov (United States)

    Avonto, Cristina; Chittiboyina, Amar G; Wang, Mei; Vasquez, Yelkaira; Rua, Diego; Khan, Ikhlas A

    2016-07-18

    Tea tree oil (TTO) is an essential oil obtained from the leaves of Melaleuca alternifolia, M. linariifolia, or M. dissitiflora. Because of the commercial importance of TTO, substitution or adulteration with other tea tree species (such as cajeput, niaouli, manuka, or kanuka oils) is common and may pose significant risks along with perceived health benefits. The distinctive nature, qualitative and quantitative compositional variation of these oils, is responsible for the various pharmacological as well as adverse effects. Authentic TTOs (especially aged ones) have been identified as potential skin sensitizers, while reports of adverse allergic reactions to the other tea trees essential oils are less frequent. Chemical sensitizers are usually electrophilic compounds, and in chemico methods have been developed to identify skin allergens in terms of their ability to bind to biological nucleophiles. However, little information is available on the assessment of sensitization potential of mixtures, such as essential oils, due to their complexity. In the present study, 10 "tea tree" oils and six major TTO constituents have been investigated for their sensitization potential using a fluorescence in chemico method. The reactivity of authentic TTOs was found to correlate with the age of the oils, while the majority of nonauthentic TTOs were less reactive, even after aging. Further thio-trapping experiments with DCYA and characterization by UHPLC-DAD-MS led to the identification of several possible DCYA-adducts which can be used to deduce the structure of the candidate reactive species. The major TTO components, terpinolene, α-terpinene, and terpinene-4-ol, were unstable under accelerated aging conditions, which led to the formation of several DCYA-adducts.

  18. Impact of emission control on PM2.5 and the chemical composition change in Beijing-Tianjin-Hebei during the APEC summit 2014.

    Science.gov (United States)

    Wen, Wei; Cheng, Shuiyuan; Chen, Xufeng; Wang, Gang; Li, Song; Wang, Xiaoqi; Liu, Xiaoyu

    2016-03-01

    The success of the emission reduction measures undertaken by authorities in the Asia-Pacific Economic Cooperation summit 2014 demonstrated that the Beijing-Tianjin-Hebei air quality can be improved by introducing integrated emission reduction measures. This paper combines observation data, emission reduction measures, and air quality simulations that were applied before, during, and after the emission control measure implement to analyze the chemical composition change and relationship between emissions and concentrations of pollutants in region. The 24-h PM2.5 samples were collected in the city Beijing, Shijiazhuang, and Tangshan during the period of 20 October to 25 November, 2014. The total PM2.5 mass was measured. PM2.5 samples were used for the analysis of inorganic elements, selected ions, and organic carbon (OC) and element carbon (EC). PM2.5 concentrations during the emission control period were decreased. Total PM2.5 concentrations were reduced by 54, 26, and 39 % when compared to non-emission control period in Beijing, Shijiazhuang, and Tangshan. The average element concentrations were reduced significantly by 75 % in Beijing, 37 % in Shijiazhuang, and 36 % in Tangshan. After the Asia-Pacific Economic Cooperation (APEC) conference, the average element concentration increased. At both cities, the concentration secondary water-soluble ions, primary carbon, and element carbon were reduced. However, the concentration of secondary carbon species increased in Beijing due to photochemical oxidants change. More stringent control of regional emissions will be needed for significant reductions of fine particulate pollution in the region to continue to improve air quality.

  19. The Chemical Composition of the Sun

    Science.gov (United States)

    Asplund, Martin; Grevesse, Nicolas; Sauval, A. Jacques; Scott, Pat

    2009-09-01

    The solar chemical composition is an important ingredient in our understanding of the formation, structure, and evolution of both the Sun and our Solar System. Furthermore, it is an essential reference standard against which the elemental contents of other astronomical objects are compared. In this review, we evaluate the current understanding of the solar photospheric composition. In particular, we present a redetermination of the abundances of nearly all available elements, using a realistic new three-dimensional (3D), time-dependent hydrodynamical model of the solar atmosphere. We have carefully considered the atomic input data and selection of spectral lines, and accounted for departures from local thermodynamic equilibrium (LTE) whenever possible. The end result is a comprehensive and homogeneous compilation of the solar elemental abundances. Particularly noteworthy findings are significantly lower abundances of C, N, O, and Ne compared to the widely used values of a decade ago. The new solar chemical composition is supported by a high degree of internal consistency between available abundance indicators, and by agreement with values obtained in the Solar Neighborhood and from the most pristine meteorites. There is, however, a stark conflict with standard models of the solar interior according to helioseismology, a discrepancy that has yet to find a satisfactory resolution.

  20. Chemical Composition of Different Varieties of Linseed

    Directory of Open Access Journals (Sweden)

    M. Laiq Khan*, M. Sharif, M. Sarwar, Sameea1 and M. Ameen

    2010-04-01

    Full Text Available The present study was conducted to investigate chemical composition of six varieties of linseed (Chandni, LS-29, LS-49, LS-70, LS-75 and LS-76. Proximate composition, mineral profile and cyanogenic glycosides (linamarin were determined. Average proximate composition values for linseed i.e. crude protein, ether extract, crude fiber, ash and nitrogen free extract were 24.18, 37.77, 4.78, 3.50 and 25.86%, respectively. Higher values of crude protein, ether extract, crude fiber and nitrogen free extract were observed in varieties LS-49, LS-70, LS-29 and Chandni, respectively. Average mineral contents in linseed i.e. Ca, Mg, K, Na, Cl, P, Cu, Fe, Mn and Zn were 0.39, 0.09, 1.41, 0.05, 0.08, 0.89, 4.67, 50.56, 8.29 and 13.55 ppm, respectively. Among micro minerals, varieties LS-29 and LS-70 were higher in Cu contents; LS-75 was higher in Fe content, while LS-49 was higher in Mn and Zn contents. Among macro minerals, level of Ca was higher in LS-70, levels of Mg, K and Na were higher in Chandni, while P was higher in LS-49. Average amount of linamarin in linseed was 31.05mg/100 gm DM. The variety LS-75 had the highest (35.22 mg/100 gm linamarin content, while variety LS-70 had least (26.22 mg/100 gm amount of linamarin. In conclusion, there is significant difference in chemical composition among linseed varieties. The varieties LS-49 showed higher crude protein content, LS-70 showed greater oil content, while LS-75 had higher content of linamarin.

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

    Science.gov (United States)

    Ashori, Alireza; Nourbakhsh, Amir

    2010-04-01

    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.

  2. Cometary Coma Chemical Composition (C4) Mission

    Science.gov (United States)

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

    1994-01-01

    Cometary exploration remains of great importance to virtually all of space science. Because comets are presumed to be remnants of the early solar nebula, they are expected to provide fundamental knowledge as to the origin and development of the solar system as well as to be key to understanding of the source of volatiles and even life itself in the inner solar system. Clearly the time for a detailed study of the composition of these apparent messages from the past has come. A comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, is now being studied as a candidate for the new Discovery program. This mission is a highly-focussed and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission. The C4 mission will concentrate on measurements that will produce an understanding of the composition and physical makeup of a cometary nucleus. The core science goals of the C4 mission are 1) to determine the chemical, elemental, and isotopic composition of a cometary nucleus and 2) to characterize the chemical and isotopic nature of its atmosphere. A related goal is to obtain temporal information about the development of the cometary coma as a function of time and orbital position. The four short-period comets -- Tempel 1, Tempel 2, Churyumov-Gerasimenko, and Wirtanen -which all appear to have acceptable dust production rates, were identified as candidate targets. Mission opportunities have been identified beginning as early as 1998. Tempel I with a launch in 1999, however, remains the baseline comet for studies of and planning the C4 mission. The C4 mission incorporates two science instruments and two engineering instruments in the payload to obtain the desired measurements. The science instruments include an advanced version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX with a sample collection system, an X-ray Fluorescence Spectrometer and a Pyrolysis-Gas Chromatograph, and a simplified version of the Neutral

  3. The impact of co-firing sunflower husk pellets with coal in a boiler on the chemical composition of flue gas

    Directory of Open Access Journals (Sweden)

    Zajemska Monika

    2017-01-01

    The calculations showed that the most important influence on the composition of the flue gas from the co-firing process of coal with sunflower husk has a composition of biomass. It should be emphasized that the results of computer simulations obtained by the authors have an useful aspect and can be applied in practice, especially to the analysis of the mechanism of chloride corrosion which is possible to occur due to the chlorine content in the biomass. They may also be useful for evaluating the unburned hydrocarbons produced by combustion of rich mixtures (λ < 1.0.

  4. Impact of Origin and Biological Source on Chemical Composition, Anticholinesterase and Antioxidant Properties of Some St. John’s Wort Species (Hypericum spp., Hypericaceae) from the Central Balkans

    OpenAIRE

    Biljana Božin; Nebojša Kladar; Nevena Grujić; Goran Anačkov; Isidora Samojlik; Neda Gavarić; Branislava Srđenović Čonić

    2013-01-01

    The study shows the influence of the origin of plant material and biological source on the in vitro antioxidant (neutralization of DPPH and OH radical, nitric oxide, and inhibition of lipid peroxidation) and anticholinesterase activity of chemically characterized and quantified ethanol extracts of ten St. John’s wort samples. The investigated samples were: five Hypericum perforatum species representatives collected at different localities, one commercial sample of Hyperici herba purchased at ...

  5. Rubber Impact on 3D Textile Composites

    Science.gov (United States)

    Heimbs, Sebastian; Van Den Broucke, Björn; Duplessis Kergomard, Yann; Dau, Frederic; Malherbe, Benoit

    2012-06-01

    A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools.

  6. Chemical Composition and Antibacterial Effects of

    Directory of Open Access Journals (Sweden)

    SS Saei Dehkordi

    2009-10-01

    Full Text Available Introduction & Objective: Rosmarinus officinalis L. as a member of the Lamiaceae family and lysozyme as a natural antibacterial agent is important in food microbiology, because of its characteristics. The aim of the present study was to determine the chemical composition and anti-listerial activity of Rosmarinus officinalis essential oil (REO alone and in combination with lysozyme for enhancement of anti-listerial activity of both substances. Materials & Methods: Rosmarinus officinalis L. was purchased from a local grocery store at Shahrekord and was identified by the Institute of Medicinal Plants, ACECR. The air-dried aerial parts were subjected to hydrodistillation using a Clevenger apparatus to obtain essential oil and yielded oil was analyzed by GC/MS. Antibacterial activity (on basis of Minimum Inhibitory Concentration (MIC of REO was studied separately and in combination with unheated lysozyme (L and heat-treated lysozyme (HTL on Listeria monocytogenes at different pH (5, 6 and 7 by a micro-broth dilution assay. The collected data were analyzed by SPSS software. Results: In the current study, 98.05% of constituents of the essential oil were identified. The major components were α-pinene (14.06%, 1,8-cineole (13.62%, verbenone (11.2%, camphor (10.51%, borneol (7.3%, 3-octanone (7.02%, camphene (5.46% and linalool (5.07%. The inhibitory action of REO was stronger at lower pH especially 5 (MIC=225 μg/mL. Inhibition by L at pH 5 was 640 μg/mL but no inhibition was seen at pH 7. HTL resulted in more effective inhibition than L, especially at pH 5 and heat-treatment 80˚C (MIC: 160 μg/mL. Conclusion: Combination of L + REO and particularly HTL + REO was led to enhancement of bacterial inhibition. It was concluded that REO by the identified chemical composition was effective alone or in combination with L or HTL on Listeria monocytogenes as a food-borne pathogen.

  7. On-line chemical composition analyzer development

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-02-01

    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.

  8. Mechanical and Chemical Properties of Bamboo/Glass Fibers Reinforced Polyester Composites

    Directory of Open Access Journals (Sweden)

    K.Sudha Madhuri,

    2016-01-01

    Full Text Available The chemical resistance of Bamboo/Glass reinforced Polyester hybrid composites to acetic acid, Nitric acid, Hydrochloric acid, Sodium hydroxide, Sodium carbonate, Benzene, Toluene, Carbon tetrachloride and Water was studied. The tensile and impact properties of these composites were also studied. The effect of alkali treatment of bamboo fibers on these properties was studied. It was observed that the tensile and impact properties of the hybrid composites increase with glass fiber content. The author investigated the interfacial bonding between Glsss/Bamboo fiber composites by SEM. These properties found to be higher when alkali treated bamboo fibers were used in hybrid composites. The hybrid fiber composites showed better resistance to the chemicals mentioned above. The elimination of amorphous hemi-cellulose with alkali treatment leading to higher crystallinity of the bamboo fibers with alkali treatment may be responsible for these observations.

  9. Chemical deinking of prints obtained by non-impact printing

    Directory of Open Access Journals (Sweden)

    Zdenka Bolanca

    2001-12-01

    Full Text Available The paper shows the results of efficiency investi-gation of chemical deinking of non-impact prints, where the principle of electrophotography is used for obtaining the latent image, on which the toner could adhere. The basis of scientific prepositions of deinking flotation and the mechanism for particle separation in the explanation of the results of experiment are given. The optical properties of hand-sheets in relation to the particle separation mechanism, their size, form and structure are discussed.The results obtained by deinking flotation of a mixed sample from the prints of non-impact printing and the conventional offset printing show clearly the influence of the specific characteristic of printing techniques and the chemical composition of toner, i.e. of printing inks on the quality of recycled fibers.

  10. Chemical Composition of Ceramic Tile Glazes

    Science.gov (United States)

    Anufrik, S. S.; Kurian, N. N.; Zhukova, I. I.; Znosko, K. F.; Belkov, M. V.

    2016-11-01

    We have carried out laser emission and x-ray fluorescence spectral analysis of glaze before and after its application to ceramic tile produced by Keramin JSC (Belarus). We have studied the internal microstructure of the ceramic samples. It was established that on the surface and within the bulk interior of all the samples, there are micropores of sizes ranging from a few micrometers to tens of micrometers and microcracks as long as several hundred micrometers. The presence of micropores on the surface of the ceramic tile leads to an increase in the water absorption level and a decrease in frost resistance. It was found that a decrease in the surface tension of ceramic tile coatings is promoted by substitution of sodium by potassium, silica by boric anhydride, magnesium and barium by calcium, CaO by sodium oxide, and SiO2 by chromium oxide. We carried out a comparative analysis of the chemical composition of glaze samples using S4 Pioneer and ElvaX x-ray fluorescence spectrometers and also an LIBS laser emission analyzer.

  11. Chemical compositions of four barium stars

    CERN Document Server

    Liang, Y C; Chen, Y Q; Qiu, H M; Zhang, B

    2003-01-01

    Chemical compositions of four barium stars HD 26886, HD 27271, HD 50082 and HD 98839 are studied based on high resolution, high signal-to-noise Echelle spectra. Results show that all of them are disk stars. Their \\alpha and iron peak elements are similar to the solar abundances. The neutron-capture process elements are overabundant relative to the Solar. The heavy-element abundances of the strong Ba star HD 50082 are higher than those of other three mild Ba stars. Its mass is 1.32Msun (+0.28,-0.22Msun), and is consistent with the average mass of strong Ba stars (1.5Msun). For mild Ba star HD 27271 and HD 26886, the derived masses are 1.90Msun (+0.25,-0.20Msun) and 2.78Msun (+0.75,-0.78M_sun), respectively, which are consistent with the average mass of mild Ba stars. We also calculate the theoretical abundances of Ba stars by combining the AGB stars nucleosynthesis and wind accretion formation scenario of Ba binary systems. The comparisons between the observed abundance patterns of the sample stars with the th...

  12. Impact of origin and biological source on chemical composition, anticholinesterase and antioxidant properties of some St. John's wort species (Hypericum spp., Hypericaceae) from the Central Balkans.

    Science.gov (United States)

    Božin, Biljana; Kladar, Nebojša; Grujić, Nevena; Anačkov, Goran; Samojlik, Isidora; Gavarić, Neda; Conić, Branislava Srđenović

    2013-09-25

    The study shows the influence of the origin of plant material and biological source on the in vitro antioxidant (neutralization of DPPH and OH radical, nitric oxide, and inhibition of lipid peroxidation) and anticholinesterase activity of chemically characterized and quantified ethanol extracts of ten St. John's wort samples. The investigated samples were: five Hypericum perforatum species representatives collected at different localities, one commercial sample of Hyperici herba purchased at a local market and four Hypericum species autochtonous to the Balkan Peninsula (H. maculatum subsp. immaculatum, H. olympicum, H. richeri subsp. grisebachii and H. barbatum). All the examined extracts exhibited notable antioxidant potential, but in most of the cases indigenous Hypericum species expressed stronger effects compared to the original source of the drug, H. perforatum. The changes in the content of phenolic compounds, especially flavonoids, hyperforin and hypericin, related to the source of the drug affected the investigated activities. Since all of the investigated species have shown prominent inhibition of acetylcholinesterase in vitro activity, they could be further investigated as potential substances in preventing of Alzheimer's disease.

  13. Measurement of cosmic ray chemical composition at Mt. Chacaltaya

    Energy Technology Data Exchange (ETDEWEB)

    Ogio, S.; Kakimoto, F.; Harada, D.; Tokunou, H.; Burgoa, O.; Tsunesada, Y. [Institute of Technology, Dept. of Physics, Tokuo (Japan); Shirasaki, Y. [National Space Development Agency of Japan, Tsukuba (Japan); Gotoh, E.; Nakatani, H.; Shimoda, S.; Nishi, K.; Tajima, N.; Yamada, Y. [The Institute of Physical and Chemical Research, Wako, Saitama (Japan); Kaneko, T. [Okayama University, Dept. of Physics, Oakayama (Japan); Matsubara, Y. [Nagoya University, Solar-Terrestrial Environment Laboratory, Nagoya, Aichi (Japan); Miranda, P.; Velarde, A. [Universidad Mayor de San Andres, Institute de Investigaciones Fisicas, La Paz (Bolivia); Mizumoto, T. [National Astronomical Observatory, Mitaka, Tokyo (Japan); Yoshii, H.; Morizawa, A. [Ehime University, Dept. of Physics, Matsuyama, Ehime (Japan); Murakami, K. [Nagoya University of Foreign Studies, Nissin, Aichi (Japan); Toyoda, Y. [Fukui University of Technology, Faculty of General Education, Fukui (Japan)

    2001-10-01

    BASJE group has measured the chemical composition of primary cosmic rays with energies around the knee with several methods. These measurements show that the averaged mass number of cosmic ray particles increases with energy up to the knee. In order to measure the chemical composition in much wider energy range, it was started a new experiment at Mt. Chacaltaya in 2000.

  14. Bio-inspired impact-resistant composites.

    Science.gov (United States)

    Grunenfelder, L K; Suksangpanya, N; Salinas, C; Milliron, G; Yaraghi, N; Herrera, S; Evans-Lutterodt, K; Nutt, S R; Zavattieri, P; Kisailus, D

    2014-09-01

    Through evolutionary processes, biological composites have been optimized to fulfil specific functions. This optimization is exemplified in the mineralized dactyl club of the smashing predator stomatopod (specifically, Odontodactylus scyllarus). This crustacean's club has been designed to withstand the thousands of high-velocity blows that it delivers to its prey. The endocuticle of this multiregional structure is characterized by a helicoidal arrangement of mineralized fiber layers, an architecture which results in impact resistance and energy absorbance. Here, we apply the helicoidal design strategy observed in the stomatopod club to the fabrication of high-performance carbon fiber-epoxy composites. Through experimental and computational methods, a helicoidal architecture is shown to reduce through-thickness damage propagation in a composite panel during an impact event and result in an increase in toughness. These findings have implications in the design of composite parts for aerospace, automotive and armor applications.

  15. THE STUDY OF CHEMICAL COMPOSITION FOR ANIMAL FATS DURING STORAGE

    OpenAIRE

    Flavia Pop; Cornel Laslo

    2009-01-01

    In this article the chemical composition for 3 types of animal fats (pork fat, beef tallow and buffalo tallow), following the variation of saturated and unsaturated fatty acids proportion during freezing storage was studied. Determination of chemical composition of animal fats is important in establishing organoleptic and physico-chemical parameters, the variation of them in time, nature and proportion of fatty acids conferring specific characteristics to them. For pork fat was determined the...

  16. Compositional, physical and chemical modification of polylactide

    Directory of Open Access Journals (Sweden)

    M. Żenkiewicz

    2010-11-01

    Full Text Available Purpose: The purpose of this article was to review some of the modification methods applied to improve mechanical, barrier and/or surface properties of polylactide (PLA.Design/methodology/approach: The presented modification methods were classified into three groups due to the dominant role of compositional, physical or chemical factor effecting the most PLA properties.Findings: It was found that incorporation of small amounts of montmorillonite up to 5% leads to formation of a nanocomposite with enhanced tensile strength and improved barrier properties. Corona treatment of pure PLA and PLA contained MMT nanofiller causes a significant decrease in the water contact angle and does not essentially affect the diiodomethane contact angle. This treatment leads to an increase in surface free energy that is much more significant for pure PLA than for PLA containing MMT nanofiller. It was also found that with increasing number up to 1000 of laser pulses of energies 5 mJ/cm2 an increase in surface free energy was observed, while the next laser pulses caused decrease of this energy. The determination and comparison of the influence of 3 wt.% of trimethylopropane trimethacylate (TMPTA and 3 wt.% of trially isocyanurate (TAIC crosslinking agents on the thermomechanical properties of electron beam irradiated PLA was reported.Research limitations/implications: A number of various modification methods are widely reported in literature. In this article a review of only such modification methods is presented, which are in line with the newest trends in polymer industry and science.Practical implications: There are a number of PLA properties, which need to be improved to satisfy specific application conditions. For that reasons researches are leading to find suitable modification methods to improve selected properties of PLA.Originality/value: This article presents some of modification methods, which are in line with the newest trends in polymer industry and

  17. Post-impact performance of composites; Predicting Compression after Impact (CAI) in composite laminates

    NARCIS (Netherlands)

    Esrall, F.

    2013-01-01

    Impact damage has been known to seriously limit the performance of composite aircraft structures. In the preliminary design phase, tens of thousands of subparts need to be analyzed for impact. Over the years, many approaches have been proposed to study the creation of impact damage and to determine

  18. Propolis chemical composition and honeybee resistance against Varroa destructor.

    Science.gov (United States)

    Popova, M; Reyes, M; Le Conte, Y; Bankova, V

    2014-01-01

    Propolis is known as honeybee chemical defence against infections and parasites. Its chemical composition is variable and depends on the specificity of the local flora. However, there are no data concerning the relationship between propolis chemical composition and honeybee colony health. We tried to answer this question, studying the chemical composition of propolis of bee colonies from an apiary near Avignon, which are tolerant to Varroa destructor, comparing it with colonies from the same apiary which are non-tolerant to the mites. The results indicated that non-tolerant colonies collected more resin than the tolerant ones. The percentage of four biologically active compounds - caffeic acid and pentenyl caffeates - was higher in propolis from tolerant colonies. The results of this study pave the way to understanding the effect of propolis in individual and social immunity of the honeybees. Further studies are needed to clarify the relationship between propolis chemical composition and honeybee colony health.

  19. Influence of Breed, Parity and Food Intake on Chemical Composition of First Colostrum in Cow

    Directory of Open Access Journals (Sweden)

    Simona Zarcula

    2010-05-01

    Full Text Available The aim of this research was to establish the influence of breed, parity and food intake on chemical composition of first colostrum. We observed that fat, proteins, lactose and dry matter were higher in cows from second and third lactation compared to those in fourth lactation. Cow's breed also influenced the colostrum composition, superior quality being obtained in case of Romanian White and Black comparing Holstein Friesian cows. The unbalanced energo-proteic ratio had a negative impact on chemical composition of first colostrum.

  20. Ultrasonic Imaging of Ballistically Impacted Composite Armour

    Directory of Open Access Journals (Sweden)

    S.S. Samant

    2013-12-01

    Full Text Available The ability of Kevlar-Polypropylene composite armour to withstand the impact of projectile (calibre 7.62 mm is investigated using immersion type ultrasonic c- scan method. The Kevlar polypropylene composite laminate is made of 36 Kevlar and 74 polypropylene layers having thickness 20 mm and are subjected to bullet impact with different striking velocities. At each location of the probe ultrasonic features peak amplitude and signal amplitude are extracted from digitized data and stored in controlling PC. Using UPGMA clustering technique, c-scan images of impacted zones of Kevlar polypropylene composite plate has been generated. The extent of core damage zone in the laminates correlated to the impact velocities of projectile. It is observed that areas of core damage zone are found to increase with the energy loss of the bullet. The area of core damage zone increases rapidly in case of shot lodging. Also peak amplitude and signal energy features are more reliable and sensitive for evaluation of damage in composite laminates.

  1. Predicting chemical impacts on vertebrate endocrine systems.

    Science.gov (United States)

    Nichols, John W; Breen, Miyuki; Denver, Robert J; Distefano, Joseph J; Edwards, Jeremy S; Hoke, Robert A; Volz, David C; Zhang, Xiaowei

    2011-01-01

    Animals have evolved diverse protective mechanisms for responding to toxic chemicals of both natural and anthropogenic origin. From a governmental regulatory perspective, these protective responses complicate efforts to establish acceptable levels of chemical exposure. To explore this issue, we considered vertebrate endocrine systems as potential targets for environmental contaminants. Using the hypothalamic-pituitary-thyroid (HPT), hypothalamic-pituitary-gonad (HPG), and hypothalamic-pituitary-adrenal (HPA) axes as case examples, we identified features of these systems that allow them to accommodate and recover from chemical insults. In doing so, a distinction was made between effects on adults and those on developing organisms. This distinction was required because endocrine system disruption in early life stages may alter development of organs and organ systems, resulting in permanent changes in phenotypic expression later in life. Risk assessments of chemicals that impact highly regulated systems must consider the dynamics of these systems in relation to complex environmental exposures. A largely unanswered question is whether successful accommodation to a toxic insult exerts a fitness cost on individual animals, resulting in adverse consequences for populations. Mechanistically based mathematical models of endocrine systems provide a means for better understanding accommodation and recovery. In the short term, these models can be used to design experiments and interpret study findings. Over the long term, a set of validated models could be used to extrapolate limited in vitro and in vivo testing data to a broader range of untested chemicals, species, and exposure scenarios. With appropriate modification, Tier 2 assays developed in support of the U.S. Environmental Protection Agency's Endocrine Disruptor Screening Program could be used to assess the potential for accommodation and recovery and inform the development of mechanistically based models.

  2. Analysis of changes in the chemical composition of the blast furnace coke at high temperatures

    Directory of Open Access Journals (Sweden)

    A. Konstanciak

    2012-12-01

    Full Text Available Purpose: The main purpose of this paper was to analyze the behavior of coke in the blast furnace. The analysis of changes in chemical composition of coke due to impact of inert gas and air at different temperatures was made. The impact of the application of the thermoabrasion coefficient on the porosity of coke was also analyzed.Design/methodology/approach: By applying the Computer Thermochemical Database of the TERMO system (REAKTOR1 and REAKTOR3 three groups of substances can be distinguished. The chemical composition of blast furnace coke and the results of calculations of changes of chemical composition of coke heat treated under certain conditions were compared. The structural studies of these materials were presented.Findings: The results of the analysis of ash produced from one of Polish cokes was taken for consideration. This is not the average composition of Polish coke ashes, nevertheless it is representative of most commonly occurring chemical compositions.Practical implications: Thanks to the thermochemical calculations it is possible to predict ash composition after the treatment in a blast furnace. Those information was crucial and had an actual impact on determining the coke quality.Originality/value: Presentation of the analytical methods which, according to author, can be very useful to evaluate and identify the heat treatment for blast furnaces cokes. The research pursued represents part of a larger project carried out within the framework of Department Extraction and Recycling of Metals, Czestochowa University of Technology.

  3. Chemical composition of upper crust in eastern China

    Institute of Scientific and Technical Information of China (English)

    鄢明才; 迟清华; 顾铁新; 王春书

    1997-01-01

    In an area of 3. 3 ×106 km" within eastern China, 28 253 rock samples were collected systematically and combined into 2 718 composite samples which were analyzed by 15 reliable methods using national preliminary certified reference materials (CRMs) for data quality monitoring. The average chemical compositions of the exposed crust, the sedimentary cover and the exposed basement as well as the upper crust for 76 chemical elements in eastern China are given.

  4. Honey: Chemical composition, stability and authenticity.

    Science.gov (United States)

    da Silva, Priscila Missio; Gauche, Cony; Gonzaga, Luciano Valdemiro; Costa, Ana Carolina Oliveira; Fett, Roseane

    2016-04-01

    The aim of this review is to describe the chemical characteristics of compounds present in honey, their stability when heated or stored for long periods of time and the parameters of identity and quality. Therefore, the chemical characteristics of these compounds were examined, such as sugars, proteins, amino acids, enzymes, organic acids, vitamins, minerals, phenolic and volatile compounds present in honey. The stability of these compounds in relation to the chemical reactions that occur by heating or prolonged storage were also discussed, with increased understanding of the behavior regarding the common processing of honey that may compromise its quality. In addition, the identity and quality standards were described, such as sugars, moisture, acidity, ash and electrical conductivity, color, 5-HMF and diastase activity, along with the minimum and maximum limits established by the Codex Alimentarius.

  5. The chemical composition of the Galileian satellites

    CERN Document Server

    Celebonovic, V

    1998-01-01

    Using the semiclassical theory of dense matter proposed by P.Savic and R.Kasanin,the mean molecular masses of the Galilean satellites of Jupiter are determined.The calculated values are fitted by plausible combinations of chemical elements,and the results are in good agreement with the observations by "Galileo".Possible cosmogonical explanations are briefly discussed.

  6. Impact of the changes in the chemical composition of pore water on chemical and physical stability of natural clays. A review of natural cases and related laboratory experiments and the ideas on natural analogues for bentonite erosion/non-erosion

    Energy Technology Data Exchange (ETDEWEB)

    Puura, Erik (Eridicon OUe, Tartu (Estonia)); Kirsimaee, Kalle (Univ. of Tartu, Inst. of Ecology and Earth Sciences, Tartu (Estonia))

    2010-01-15

    A scientific literature survey was compiled with the specific objective to find information for smectite mobilization and/or retention in natural clay formations caused by contact with water with low ionic concentrations such as can be expected during and after an ice age. Evidence was sought if smectite particles are lost from the clay to the water and if accessory minerals that remain could form a growing filter slowing down or stopping further loss of smectite. Bentonites are present in geological layers for hundreds of millions of years. There is limited exchange with surrounding layers, eg K transported into the bentonite layer from surrounding shale layers leading to the increased illite % in smectite-illite of the bentonite. Another process is silicification of surrounding layers leading to lowered permeability of surrounding rocks. Geological literature data on historical bentonites do not consider colloid formation in low ionic strength water as relevant mechanism for smectite mobilization. However there are no studied cases where this could be a relevant mechanism (as proposed by colloid release scenario). Soil researchers have studied the mechanism of colloid release in laboratory experiments and have found that there has to be an abrupt change in infiltrating water quality leading to 'osmotic explosion'. Clogging the pores in the lower part of the soil column has followed, leading to dramatic decrease of hydraulic conductivity in vertical profile and increased surface runoff. So, although limited, there are literature evidences of clay colloids release from bentonites/smectites caused by low-ionic circumneutral water. The geological settings to look for natural analogue studies include (1) Bentonite/smectite similar to what is used in repository. (2) Water similar to the composition of glacial meltwater. (3) Scenario similar to what is proposed in the bentonite erosion project. The problem related to the study of historical bentonite profiles

  7. Differential effects of conifer and broadleaf litter inputs on soil organic carbon chemical composition through altered soil microbial community composition

    Science.gov (United States)

    Wang, Hui; Liu, Shi-Rong; Wang, Jing-Xin; Shi, Zuo-Min; Xu, Jia; Hong, Pi-Zheng; Ming, An-Gang; Yu, Hao-Long; Chen, Lin; Lu, Li-Hua; Cai, Dao-Xiong

    2016-06-01

    A strategic selection of tree species will shift the type and quality of litter input, and subsequently magnitude and composition of the soil organic carbon (SOC) through soil microbial community. We conducted a manipulative experiment in randomized block design with leaf litter inputs of four native subtropical tree species in a Pinus massoniana plantation in southern China and found that the chemical composition of SOC did not differ significantly among treatments until after 28 months of the experiment. Contrasting leaf litter inputs had significant impacts on the amounts of total microbial, Gram-positive bacterial, and actinomycic PLFAs, but not on the amounts of total bacterial, Gram-negative bacterial, and fungal PLFAs. There were significant differences in alkyl/O-alkyl C in soils among the leaf litter input treatments, but no apparent differences in the proportions of chemical compositions (alkyl, O-alkyl, aromatic, and carbonyl C) in SOC. Soil alkyl/O-alkyl C was significantly related to the amounts of total microbial, and Gram-positive bacterial PLFAs, but not to the chemical compositions of leaf litter. Our findings suggest that changes in forest leaf litter inputs could result in changes in chemical stability of SOC through the altered microbial community composition.

  8. Chemical Analysis of Emu Feather Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    V.Chandra sekhar

    2015-07-01

    Full Text Available A composite is usually made up of at least two materials out of which one is binding material called as matrix and other is a reinforcement material known as fiber. For the past ten years research is going on to explore possible composites with natural fiber like plant fibers and animal fibers. The important characteristics of composites are their strength, hardness light in weight. It is also necessary to study about the resistance of the composites for deferent chemicals. In the present work, composites prepared with epoxy (Araldite LY-556 as resin and „emu‟ bird feathers as fiber have been tested for chemical resistance. The composites were prepared by varying fiber loading (P of „emu‟ feathers ranging from 1 to 5 and length (L of feather fibers from 1 to 5 cm. The composites thus prepared were subjected to various chemicals (Acids, Alkalis, solvents etc.. Observations were plotted and studied. The results reveal that there will be weight gain for the composite samples after three days, when treated with Hydrochloric acid, Sodium carbonate, Acetic acid, Sodium hydroxide, Nitric acid and Ammonium hydroxide. Weight loss was observed for all the samples including pure epoxy when treated with Benzene, Carbon tetra chloride and Toluene.

  9. Chemical composition of Hanford Tank SY-102

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-01

    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.

  10. Impact and damage of an armour composite

    Science.gov (United States)

    Resnyansky, A. D.; Parry, S.; Bourne, N. K.; Townsend, D.; James, B.

    2017-01-01

    The current study assesses the application of the Taylor Test to validate hydrocode modelling of composite materials. 0° in-plane and through-thickness rods were cut from a 25 mm thick composite panel, made from autoclave cured 0°, 90° uni-directional carbon/epoxy prepreg. The rods were fired against a semi-infinite steel anvil and high-speed video imaging was used to capture the difference in rod shape and damage patterns during the experiments. Results of simulation with a rate sensitive, transversely isotropic composite material model implemented in the CTH hydrocode were compared with the present experiments. The model showed good correlation with global deformation of the rods, and was used to qualitatively assess some of the asymmetric deformation features in the material. As the present model implementation did not account for damage at this stage, it did not predict inter-ply delamination normal to the impact face for the in-plane 0° rods and that parallel to the impact face in the through-thickness samples.

  11. Porosity prediction of calcium phosphate cements based on chemical composition.

    Science.gov (United States)

    Öhman, Caroline; Unosson, Johanna; Carlsson, Elin; Ginebra, Maria Pau; Persson, Cecilia; Engqvist, Håkan

    2015-07-01

    The porosity of calcium phosphate cements has an impact on several important parameters, such as strength, resorbability and bioactivity. A model to predict the porosity for biomedical cements would hence be a useful tool. At the moment such a model only exists for Portland cements. The aim of this study was to develop and validate a first porosity prediction model for calcium phosphate cements. On the basis of chemical reaction, molar weight and density of components, a volume-based model was developed and validated using calcium phosphate cement as model material. 60 mol% β-tricalcium phosphate and 40 mol% monocalcium phosphate monohydrate were mixed with deionized water, at different liquid-to-powder ratios. Samples were set for 24 h at 37°C and 100% relative humidity. Thereafter, samples were dried either under vacuum at room temperature for 24 h or in air at 37 °C for 7 days. Porosity and phase composition were determined. It was found that the two drying protocols led to the formation of brushite and monetite, respectively. The model was found to predict well the experimental values and also data reported in the literature for apatite cements, as deduced from the small absolute average residual errors (brushite, monetite and apatite cements. The model gives a good estimate of the final porosity and has the potential to be used as a porosity prediction tool in the biomedical cement field.

  12. Sensory properties and chemical composition of Sharri cheese from Kosovo

    Directory of Open Access Journals (Sweden)

    Agim Rysha

    2014-11-01

    Full Text Available Food sensory properties, analyses and chemical composition are very important because they provide information about product quality and end-user acceptance or preferences. An assessment of sensory characteristics and chemical composition of mountain sheep and cow’s-milk cheese from shepherd’s huts and industrial manufacturers in Kosovo was carried out. Consumer-oriented tests using a 9 point hedonic scale were conducted in order to determine Sharri cheese acceptability. Chemical parameters (fat content, fat content of dry matter, acidity, protein, dry matter, mineral and water content and sodium chloride content of 45-day brine cheese samples were also analyzed. Chemical and sensory assessment demonstrated large property differences. A recommendation stems from the results showing that the standardization of both artisanal and industrial production of Sharri cheese is required.

  13. Chemical composition analysis and authentication of whisky.

    Science.gov (United States)

    Wiśniewska, Paulina; Dymerski, Tomasz; Wardencki, Waldemar; Namieśnik, Jacek

    2015-08-30

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

  14. Fuel options from microalgae with representative chemical compositions

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D. A.

    1984-07-01

    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.

  15. Characterization of Impact in Composite Laminates

    Science.gov (United States)

    Minnaar, Karel; Zhou, Min

    2002-07-01

    A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displacement, and velocity of impacted specimens to be recorded and analyzed. Numerical simulations are conducted using a cohesive finite element method. The method employs a cohesive zone model to simulate in-ply cracking and interlaminar delamination and a transversely isotropic, elastic model to characterize the bulk behavior of each ply. The simulations provide time-resolved characterization of damage during the impact loading. The time at which delamination is detected decreases as the impact velocity is increased, and delamination is detected at similar surface displacements. The progression of damage changes as the bonding strength between plies is increased. The speed of delamination decreases as the bonding strength is increased.

  16. An investigation into the chemical composition of alternative invertebrate prey

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Dierenfeld, E.S.

    2012-01-01

    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 (Grompha

  17. Probabilistic thermo-chemical analysis of a pultruded composite rod

    DEFF Research Database (Denmark)

    Baran, Ismet; Tutum, Cem Celal; Hattel, Jesper Henri

    2012-01-01

    In the present study the deterministic thermo-chemical pultrusion simulation of a composite rod taken from the literature [7] is used as a validation case. The predicted centerline temperature and cure degree profiles of the rod match well with those in the literature [7]. Following the validation...

  18. Probabilistic thermo-chemical analysis of a pultruded composite rod

    NARCIS (Netherlands)

    Baran, Ismet; Tutum, Cem C.; Hattel, Jesper H.

    2012-01-01

    In the present study the deterministic thermo-chemical pultrusion simulation of a composite rod taken from the literature [7] is used as a validation case. The predicted centerline temperature and cure degree profiles of the rod match well with those in the literature [7]. Following the validation c

  19. Chemical fractionation resulting from the hypervelocity impact process on metallic targets

    Science.gov (United States)

    Libourel, Guy; Ganino, Clément; Michel, Patrick; Nakamura, Akiko

    2016-10-01

    In a regime of hypervelocity impact cratering, the internal energy deposited in target + projectile region is large enough to melt and/or vaporize part of the material involved, which expands rapidly away from the impact site. Fast and energetic impact processes have therefore important chemical consequences on the projectile and target rock transformations during major impact events. Several physical and chemical processes occurred indeed in the short duration of the impact, e.g., melting, coating, mixing, condensation, crystallization, redox reactions, quenching, etc., all concurring to alter both projectile and target composition on the irreversible way.In order to document such hypervelocity impact chemical fractionation, we have started a program of impact experiments by shooting doped (27 trace elements) millimeter–sized basalt projectiles on metallic target using a two stages light gas gun. With impact velocity in the range from 0.25 to 7 km.s-1, these experiments are aimed i) to characterize chemically and texturally all the post-mortem materials (e.g., target, crater, impact melt, condensates, and ejectas), in order ii) to make a chemical mass balance budget of the process, and iii) to relate it to the kinetic energy involved in the hypervelocity impacts for scaling law purpose. Irrespective of the incident velocities, our preliminary results show the importance of redox processes, the significant changes in the ejecta composition (e.g., iron enrichment) and the systematic coating of the crater by the impact melt [1]. On the target side, characterizations of the microstructure of the shocked iron alloys to better constrain the shielding processes. We also show how these results have great implications in our understanding on the current surface properties of small bodies, and chiefly in the case of M-type asteroids. [1] Ganino C, Libourel G, Nakamura AM & Michel P (2015) Goldschmidt Abstracts, 2015 990.

  20. Interpreting chemical compositions of small scale basaltic systems: A review

    Science.gov (United States)

    McGee, Lucy E.; Smith, Ian E. M.

    2016-10-01

    Small scale basaltic magmatic systems occur in all of the major tectonic environments of planet Earth and are characteristically expressed at the Earth's surface as fields of small monogenetic cones. The chemical compositions of the materials that make up these cones reflect processes of magma generation and differentiation that occur in their plumbing system. The volumes of magmas involved are very small and significantly their compositional ranges reveal remarkably complex processes which are overwhelmed or homogenized in larger scale systems. Commonly, compositions are basaltic, alkalic and enriched in light rare earth elements and large ion lithophile elements, although the spectrum extends from highly enriched nephelinites to subalkalic and tholeiitic basalts. Isotopic analyses of rocks from volcanic fields almost always display compositions which can only be explained by the interaction of two or more mantle sources. Ultimately their basaltic magmas originate by small scale melting of mantle sources. Compositional variety is testament to melting processes at different depths, a range of melting proportions, a heterogeneous source and fractionation, magma mixing and assimilation within the plumbing system that brings magmas to the surface. The fact that such a variety of compositions is preserved in a single field shows that isolation of individual melting events and their ascent is an important and possibly defining feature of monogenetic volcanism, as well as the window their chemical behavior provides into the complex process of melt generation and extraction in the Earth's upper mantle.

  1. Design and control of chemical compositions for high-performance austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Gong Wenbang

    2012-05-01

    Full Text Available This paper presents the effects of chemical compositions of austempered ductile iron (ADI on casting quality, heat treatment process parameters and mechanical properties of final products. Through experiment and production practice, the impacts of carbon equivalent on ADI and its mechanical properties have been studied. Proper content ranges for carbon and silicon have been obtained to avoid ADI casting shrinkage and graphite floatation, as well as to achieve the optimal mechanical properties. According to the impact of silicon content on austenite phase transformation, the existing form of carbon in ADI has been analyzed, and also the formula and diagram showing the relationship between austenitizing temperature and carbon content in austenite have been deduced. The chemical composition range for high performance ADI and its control points have been recommended, to serve as a reference for production process.

  2. Surface chemical composition analysis of heat-treated bamboo

    Science.gov (United States)

    Meng, Fan-dan; Yu, Yang-lun; Zhang, Ya-mei; Yu, Wen-ji; Gao, Jian-min

    2016-05-01

    In this study, the effect of heat treatment on the chemical composition of bamboo slivers was studied. The chemical properties of the samples were examined by chemical analysis. Results showed a decrease in the contents of holocellulose and α-cellulose, as well as an increase in the contents of lignin and extractives. Changes in the chemical structure of bamboo components were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR spectroscopy results indicated that hemicellulose contents decrease, whereas lignin contents increase after heat treatment. Ester formation linked to lignin decreased the hygroscopicity of the bamboo samples and consequently improved their dimensional stability and durability. XPS spectroscopy results showed that hemicelluloses and celluloses are relatively more sensitive to the heating process than lignin. As a consequence, hemicellulose and cellulose contents decreased, whereas lignin contents increased during heat treatment. The results obtained in this study provide useful information for the future utilization of heat-treated bamboo.

  3. Composition and placement process for oil field chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Cantu, L.A.; Yost, M.E.

    1991-01-22

    This patent describes a process for the continuous release of an oil field chemical within a subterranean hydrocarbon bearing formation or wellbore penetrating such formation. It comprises placing the oil field chemical in a polymeric microcapsule; dispersing such polymeric microcapsules; introducing the wellbore fluid containing the microcapsules into a well bore or subterranean formation through a wellbore; then allowing water and temperature at formation conditions to degrade; continuously releasing the chemical from the degraded microcapsules. This patent describes a composition comprising an oil field chemical incorporated in a polymeric microcapsule comprising the condensation product of hydroxyacetic acid monomer or hydroxyacetic acid co-condensed with up to 15 percent by weight of other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid- containing moieties. The product has a number average molecular weight of from about 200 to about 4000.

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

    Science.gov (United States)

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

    2013-08-15

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

  5. Features of a chemical composition of dry leaves of Steviavebaudiana

    Directory of Open Access Journals (Sweden)

    Irina Borisovna Krasina

    2016-05-01

    Full Text Available This work is dedicated to the study of a chemical composition of dry leaves of Stevia. Dry leaves of Stevia contain diterpene glycosides that contribute to their sweet taste, which makes possible the use of Stevia as a sugar substitute in a production of flour confectionery products. The evaluation of amino acid composition of dried leaves of Stevia showed that their composition includes 7 essential amino acids, among them the limiting amino acid is valine.During experimental researches it was established that they are containing in a sufficient quantity water-soluble and fat-soluble vitamins in their composition. We have studied the effect of processing conditions on the degree of milling of dry leaves of Stevia. It was revealed that the pressure of 5 MPa in the contact zone of the working elements do not guarantee a product with a desired degree of milling. Milling of dried leaves of Stevia at a pressure equal to 10 MPa, allows achieving a high degree of size reduction with a simultaneous formation of the main physical and chemical characteristics of amilledproduct. It was established that granulometric composition of dry leaves of Stevia, obtained by milling in a rotor-roller disintegrator, presents the highest content of particles with a size from 5 to 30 μm, ensuring high consumer properties of the obtained biologically active additives (BAA.

  6. Surface chemical composition analysis of heat-treated bamboo

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fan-dan, E-mail: fandan_meng@163.com [MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083 (China); Yu, Yang-lun, E-mail: yuyanglun@caf.ac.cn [Research Institute of Wood Industry, Chinese Academy of Forestry, No 1 Dongxiaofu, Haidian District, Beijing 100091 (China); Zhang, Ya-mei, E-mail: zhangyamei@caf.ac.cn [Research Institute of Wood Industry, Chinese Academy of Forestry, No 1 Dongxiaofu, Haidian District, Beijing 100091 (China); Yu, Wen-ji, E-mail: yuwenji@caf.ac.cn [Research Institute of Wood Industry, Chinese Academy of Forestry, No 1 Dongxiaofu, Haidian District, Beijing 100091 (China); Gao, Jian-min, E-mail: gaojm@bjfu.edu.cn [MOE Key Laboratory of Wooden Material Science and Application, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083 (China)

    2016-05-15

    Highlights: • Investigate the detailed chemical components contents change of bamboo due to heating. • Chemical analysis of bamboo main components during heating. • Identify the connection between the oxygen to carbon atomic ratio changes and chemical degradation. - Abstract: In this study, the effect of heat treatment on the chemical composition of bamboo slivers was studied. The chemical properties of the samples were examined by chemical analysis. Results showed a decrease in the contents of holocellulose and α-cellulose, as well as an increase in the contents of lignin and extractives. Changes in the chemical structure of bamboo components were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). FTIR spectroscopy results indicated that hemicellulose contents decrease, whereas lignin contents increase after heat treatment. Ester formation linked to lignin decreased the hygroscopicity of the bamboo samples and consequently improved their dimensional stability and durability. XPS spectroscopy results showed that hemicelluloses and celluloses are relatively more sensitive to the heating process than lignin. As a consequence, hemicellulose and cellulose contents decreased, whereas lignin contents increased during heat treatment. The results obtained in this study provide useful information for the future utilization of heat-treated bamboo.

  7. Chemical composition of material fractions in Danish household waste

    DEFF Research Database (Denmark)

    Riber, Christian; Petersen, Claus; Christensen, Thomas Højlund

    2009-01-01

    method, because of the larger quantities included and the more homogenous material to sample from. Differences between the direct and the direct methods led to corrections in the of heavy metal concentration of a few fractions. The majority of the energy content of the waste originates from organic waste......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 20 tonnes of waste collected from 2200 households; and an indirect method where...... batches of 80-1200 tonnes of unsorted household waste was incinerated and the content of the waste determined from the content of the outputs from the incinerator. The indirect method is believed to better represent the small but highly contaminated material fractions (e,g., batteries) than the direct...

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

    Science.gov (United States)

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

    2002-08-01

    In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid-base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system.

  9. Chemical Composition of Essential Oil from Marrubium Vulgare L. Leaves

    OpenAIRE

    Bayir, Burcu; Gündüz, Hatice; Usta, Tuba; Şahin, Esma; Özdemir, Zeynep; Kayır, Ömer; Sen, Özkan; Akşit, Hüseyin; Elmastaş, Mahfuz; Erenler, Ramazan

    2014-01-01

    – The essential oils are significant for pharmaceutical, food and cosmetic industries. Marrubium vulgare L. has been used as a traditional medicine to treat the various illnesses. The chemical composition of the essential oil from leaves of Marrubium vulgare L.was obtained by steam distillation using the Clevenger apparatus. The oil was analyzed by gas chromatography and mass spectrometry (GC-MS). The main constituent of the oil was α-pinene (28.85%)

  10. Chemical composition and biological activity of the plum seed extract

    OpenAIRE

    Savić, Ivan M.; Nikolić, Vesna D.; Savić-Gajić, Ivana M.; Kundaković, Tatjana D.; Stanojković, Tatjana P.; Najman, Stevo J.; id_orcid 0000-0002-2411-9802

    2016-01-01

    The aim of this paper was to estimate the biological activity of the plum seed extract and to define the chemical composition by using the ESI-MS method. During the investigation of the antioxidant activity, the extract showed a better ability to inhibit DPPH radicals compared with amygdalin standard. The results of the antimicrobial study indicate that the extract has a greater effect on Gram-negative bacteria compared with amygdalin. Gram-positive bacteria and fungi remained resistant in bo...

  11. The chemical composition at a galactocentric distance of 13 KPC

    Science.gov (United States)

    Rolleston, W. R. J.; Dufton, P. L.; Fitzsimmons, A.

    1994-04-01

    High-resolution observations of two very sharp-lined, main-sequence B-type stars, associated with the H II region S 285, have been obtained using the ISIS spectrograph on the William Herschel Telescope. The spectroscopic data have been analysed using local thermodynamic equilibrium (LTE) model-atmosphere techniques to derive the stellar atmospheric parameters, chemical compositions and a mean distance of 4.3 kpc. As the lifetimes for these stars were calculated to be less than 6 Myrs, their photospheric abundances should reflect that of their natal interstellar material. Individual element abundances deduced for both stars were generally in excellent agreement (differing on average by less than 0.1 dex), although there is some evidence to suggest that the stars formed from material which had different nitrogen abundances. Both stars appear to have chemical compositions similar to that found in the solar neighborhood, which is consistent with a zero abundance gradient over these galactocentric distances. The chemical compositions of the stars associated with S 285 have also been compared with three other clusters at similar galactocentric distances (Bochum 1, NGC 1893 and Dolidze 25). From a differential analysis, Dolidze 25 appears to have a mean metal deficiency of approximately 0.7 dex, with oxygen being less underabundant, while the other two clusters have similar abundances to S 285. We conclude that these results are inconsistent with the concept of a linear galactic abundance gradient, that the chemical composition is not unique and that there are significant abundance variations over distance scales of 1 kpc at these large galactocentric distances.

  12. Chemical composition of silica-based biocidal modifier

    Directory of Open Access Journals (Sweden)

    Grishina Anna Nikolaevna

    2016-11-01

    Full Text Available Increase of the amount of fungi spores and micotixines causes the increase in the number of different diseases. Because of this, ensuring the biological safety in buildings is becoming more and more important today. The preferred way to guarantee the biological safety of a building is to employ modern building materials that prevent the settlement of the fungi colonies on the inner surfaces of walls. Such building materials can be produced using novel biocidal modifiers that allow controlling the number of microorganisms on the surface and in the bulk of a composite construction. The precipitation product of zinc hydrosilicates and sodium sulfate is one of the mentioned modifiers. Till now, the exact chemical composition of such precipitation product is controversial; it is obvious, though, that the efficacy of the biocidal modifier is mostly determined by the type of the copper compounds. In the present work an integrated approach is used for the investigation of the chemical composition of the biocidal modifier. Such an approach consists in the examination of the modifier’s composition by means of different, yet complementary, research methods: X-ray diffraction, infrared spectroscopy and DTA. It is shown that the chemical composition of the modifier mainly depends on the amount of precipitant. X-ray diffraction reveals that the major part of the modifier is represented by amorphous phase. Along with the increase of the precipitant’s amount the crystalline phase Zn4SO4(OH6•xH2O formation takes place. Such a crystalline phase is not appropriate as a component of the biocidal modifier. Another two methods - DTA and IR spectroscopy - reveal that the amorphous phase consists essentially of zinc hydrosilicates.

  13. Interfacial studies of chemical-vapor-infiltrated ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, J.J. (United Technologies Research Center, East Hartford, CT (USA))

    1990-06-15

    The objective of this program was to investigate the fiber-matrix interfacial chemistry in chemical-vapor-infiltrated SiC matrix composites utilizing NICALON SiC and Nextel 400 mullite fibers and how this interface influences composite properties such as strength, toughness and environmental stability. The SiC matrix was deposited using three different reactants: methyldichlorosilane, methyltrichlorosilane and dimethyldichlorosilane. It was found that by varying the reactant gas flow rates, the ratio of carrier gas to reactant gas, the type of carrier gas (hydrogen or argon), the flushing gas used in the reactor prior to deposition (hydrogen or argon) or the type of silane reactant gas used, the composition of the deposited SiC could be varied from very silicon rich (75 at.%) to carbon rich (60%) to almost pure carbon. Stoichiometric SiC was found to bond very strongly to both NICALON and Nextel fibers, resulting in a weak and brittle composite. A thin carbon interfacial layer deposited either deliberately by the decomposition of methane or inadvertently by the introduction of argon into the reactor prior to silane flow resulted in a weakly bonded fiber-matrix interface and strong and tough composites. However, composites with this type of interface were not oxidatively stable. Preliminary results point ot the use of a carbon-rich SiC (mixture of carbon plus SiC) interfacial zone to achieve a relatively weak, crack-deflecting fiber-matrix bond but also exhibiting oxidative stability. (orig.).

  14. Chemical composition of the clays as indicator raw material sources

    Directory of Open Access Journals (Sweden)

    Khramchenkova Rezida Kh

    2014-06-01

    Full Text Available The paper presents the results of study on the chemical composition of unglazed pottery from the excavations of the Bulgar fortified settlement site and the clay, selected from the modern deposits of ceramic raw materials located near the medieval settlement sites. Significant differences in macro- and microelement composition of different groups of ceramics have been revealed. The difference in the macroelemental composition is largely determined by the ceramic fabric recipe. Thus, the high calcium content corresponds to the addition of river shells, the high content of silicon results from sand addition. A more interesting picture has been revealed in the course of studies of the so-called “trace elements” (microelements. Nine groups of ceramics with different elemental set have been distinguished. The first two groups consist of imported ceramics; other groups have demonstrated a rather pronounced elemental composition. The most notable variations are observed in chromium, vanadium and nickel content. Similar microelement composition variety has been observed in clays from deposits of different localization, while the concentration of the mentioned elements in a variety of clays also differs considerably. Therefore, marker elements typical of different clays have been identified. A comparative analysis of the data obtained for clay raw materials and ceramics has been conducted. The results demonstrate the potential of studying the elemental composition in order to determine the localization of the raw material sources for ceramic production.

  15. Chemical composition and surface charge properties of montmorillonite

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-wen; HU Min; HU Yue-hua

    2008-01-01

    The effects of the cell parameter and chemical composition on the surface charge properties of five kinds of different colour montmorillonites were studied. The results indicate that the surface isoelectric point(IEP) of the montmorillonite shows positive correlation with the mass fractions of Fe2O3 and K20, but it has little relation to the mass fractions of other chemical compositions. At around pH=6.8, the surface zeta potential of the montmorillonite shows the negative relationship with the mass fractions of Fe2O3 and MgO, but it does not linearly correlate to the mass fractions of other chemical compositions. Cell parameter(b0) of the montmofillonite expresses negative linear relationship with mass fractions of K2O and Na2O, so does c0sinβ with mass fractions of SiO2 and Fe2O3. And there is no specific relationship between bo and IEP of different montmori Uonites, but there is positive correlation between c0sinβ and IEP of different montmorillonite samples.

  16. On the chemical composition of Titan's dry lakebed evaporites

    CERN Document Server

    Cordier, Daniel; Ferreira, Abel

    2013-01-01

    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.

  17. Dust as interstellar catalyst - II. How chemical desorption impacts the gas

    CERN Document Server

    Cazaux, S; Dulieu, F; Hocuk, S

    2015-01-01

    Context. Interstellar dust particles, which represent 1% of the total mass, are recognized to be very powerful interstellar catalysts in star-forming regions. The presence of dust can have a strong impact on the chemical composition of molecular clouds. While observations show that many species that formed onto dust grains populate the gas phase, the process that transforms solid state into gas phase remains unclear. Aims. The aim of this paper is to consider the chemical desorption process, i.e. the process that releases solid species into the gas phase, in astrochemical models. These models allow determining the chemical composition of star-forming environments with an accurate treatment of the solid-phase chemistry. Methods. In paper I we derived a formula based on experimental studies with which we quantified the efficiencies of the chemical desorption process. Here we extend these results to astrophysical conditions. Results. The simulations of astrophysical environments show that the abundances of gas-p...

  18. Investigation on low velocity impact resistance of SMA composite material

    Science.gov (United States)

    Hu, Dianyin; Zhang, Long; Wang, Rongqiao; Zhang, Xiaoyong

    2016-04-01

    A method to improve low velocity impact resistance of aeroengine composite casing using shape memory alloy's properties of shape memory(SM) and super-elasticity(SE) is proposed in this study. Firstly, a numerical modeling of SMA reinforced composite laminate under low velocity impact load with impact velocity of 10 m/s is established based on its constitutive model implemented by the VUMAT subroutine of commercial software ABAQUS. Secondly, the responses of SMA composite laminate including stress and deflection distributions were achieved through transient analysis under low velocity impact load. Numerical results show that both peak stress and deflection values of SMA composite laminate are less than that without SMA, which proves that embedding SMA into the composite structure can effectively improve the low velocity impact performance of composite structure. Finally, the influence of SM and SE on low velocity impact resistance is quantitatively investigated. The values of peak stress and deflection of SMA composite based on SM property decrease by 18.28% and 9.43% respectively, compared with those without SMA, instead of 12.87% and 5.19% based on SE. In conclusion, this proposed model described the impact damage of SMA composite structure and turned to be a more beneficial method to enhance the impact resistance by utilizing SM effect.

  19. Preliminary study of chemical compositional data from Amazon ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Toyota, Rosimeiri G.; Munita, Casimiro S.; Luz, Fabio A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rosimeiritoy@yahoo.com.br; Neves, Eduardo G. [Museu de Arqueologia e Etnolgia, Sao Paulo, SP (Brazil)]. E-mail: egneves@usp.br; Oliveira, Paulo M.S. [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Inst. de Matematica e Estatistica]. E-mail: poliver@usp.br

    2005-07-01

    Eighty seven ceramic samples from Acutuba, Lago Grande and Osvaldo archaeological sites located in the confluence of the rivers Negro and Solimoes were submitted to chemical analysis using instrumental neutron activation analysis to determine As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Rb, Na, Nd, Sb, Sc, Sm, Ta, Tb, Th, Yb, Zn, and U. The database were studied using the Mahalanobis distance, and discriminant analysis. The results showed that the ceramics of each site differ from each other in chemical composition and that they form three different groups. Chemical classification of the ceramics suggests that vessels were made locally, as only ceramics from the same area show homogeneity of data. (author)

  20. Peculiarities of chemical composition of sainfoin seeds powder

    Directory of Open Access Journals (Sweden)

    Natalia Aleksandrovna Tarasenko

    2015-09-01

    Full Text Available This paper is devoted to studying chemical composition of the powder of the seeds of non-traditional legume, sainfoin. The experimental studies showed that crushed seeds of sainfoin make a flowing fine powder of light brown color with a pleasant unpronounced specific smell with floral notes. The taste is grassy with the after-taste typical for legumes. The chemical composition of sainfoin seeds is dominated by proteins and fiber, and fat content does not exceed 8%. The total content of amino-acids is 26.94/100 g of the product, with the share of indispensable ones being 37.85%. The limiting amino acid is tryptophan (48.0 %. By the composition of essential amino acids, proteins of sainfoin seeds are slightly inferior to the proteins of soybean seeds, but are better than the proteins of peanut seeds. The composition of fatty acid of the lipid complex of sainfoin seeds is dominated by (over 40% of the total linolenic ω-3 acid with sufficiently low (less than 20% of the total content of linoleic ω-6 acid. The lipid composition of sainfoin seeds, along with triacylglycerols, contains about 40% of related lipids, which are dominated by sterols, aliphatic alcohols, phospholipids and tocopherols. All this makes the lipid complex of sainfoin seed a promising means of adjusting fatty acids composition in food products of functional and specialized purpose, dietary supplements, and a valuable raw material for creating pharmaceutical substances and preparations. Adding sainfoin seeds powder into the nutritive medium has no inhibitory effect on development of the tested organism. At the same time, 58% of the organism's physiological need for protein is satifsied, as compared to caseine.

  1. Endocrine Disrupting Chemical Impacts on Aquatic Systems

    Science.gov (United States)

    Jobling, Susan

    2014-07-01

    We often talk about the importance of water, but one area that's often overlooked is the safety of our water supply. How many people actually think about the purity of their water when they turn on the tap? We may have real reason to be concerned because our water delivery systems and treatment technology seem to be stuck in the past, relying on old water treatment and water delivery systems. While these systems still do a great job filtering out particles, parasites and bacteria, they usually fail to remove 21st century contaminants like pesticides, industrial chemicals, lead, pharmaceuticals and arsenic. Indeed our water contains already a whole plethora of things in daily commerce and pharmaceuticals are increasingly showing up in the water supply, including antibiotics, anti-convulsants, mood altering medications and sex hormones. As the world's dependence on chemicals grows, our water supplies will continue to feel the effects, which inevitably will touch every person on this planet...

  2. Temperature Effects on Hybrid Composite Plates Under Impact Loads

    Directory of Open Access Journals (Sweden)

    Metin SAYER

    2009-03-01

    Full Text Available In this work, impact responses of carbon-glass fiber/epoxy (hybrid composites were investigated under various temperatures and increasing impact energies. The increasing impact energies were applied to the specimens at various temperatures as -20, 0, 20 and 40 oC until perforation took place of specimens. Those specimens are composed by two types of fiber orientation with eight laminates hybrid composites. An Energy profiling diagram, used for showing the relationship between impact and absorbed energy, has been used to obtain penetration and perforation thresholds of hybrid composites. Beside those, temperature effects on impact characteristics such as maximum contact force (Fmax, total deflection (d and maximum contact duration (t were also presented in figures. Finally, glass and carbon fibers exhibited more brittle characteristics at -20 oC according to other temperatures. So, perforation threshold of each hybrid composites at -20 oC was found higher than other temperatures. Keywords : Hybrid composite

  3. Analysis of high velocity impact on hybrid composite fan blades

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1979-01-01

    This paper describes recent developments in the analysis of high velocity impact of composite blades using a computerized capability which consists of coupling a composites mechanics code with the direct-time integration features of NASTRAN. The application of the capability to determine the linear dynamic response of an intraply hybrid composite aircraft engine fan blade is described in detail. The predicted results agree with measured data. The results also show that the impact stresses reach sufficiently high magnitudes to cause failures in the impact region at early times of the impact event.

  4. Towards the regulation of aerosol emissions by their potential health impact: Assessing adverse effects of aerosols from wood combustion and ship diesel engine emissions by combining comprehensive data on the chemical composition and their toxicological effects on human lung cells

    Science.gov (United States)

    Zimmermann, R.; Streibel, T.; Dittmar, G.; Kanashova, T.; Buters, J.; Öder, S.; Paur, H. R.; Dilger, M.; Weiss, C.; Harndorf, H.; Stengel, B.; Hirvonen, M. R.; Jokiniemi, J.; Hiller, K.; Sapcariu, S.; Sippula, O.; Orasche, J.; Müller, L.; Rheda, A.; Passig, J.; Radischat, C.; Czech, H.; Tiita, P.; Jalava, P.; Kasurinen, S.; Schwemer, T.; Yli-Prilä, P.; Tissari, J.; Lamberg, H.; Schnelle-Kreis, J.

    2014-12-01

    Ship engine emissions are important regarding lung and cardiovascular diseases in coastal regions worldwide. Bio mass burning is made responsible for adverse health effects in many cities and rural regions. The Virtual Helmholtz Institute-HICE (www.hice-vi.eu) addresses chemical & physical properties and health effects of anthropogenic combustion emissions. Typical lung cell responses to combustion aerosols include inflammation and apoptosis, but a molecular link with the specific chemical composition in particular of ship emissions has not been established. Through an air-liquid interface exposure system (ALI), we exposed human lung cells at-site to exhaust fumes from a ship engine running on common heavy fuel oil (HFO) and cleaner-burning diesel fuel (DF) as well as to emissions of wood combustion compliances. A special field deployable ALI-exposition system and a mobile S2-biological laboratory were developed for this study. Human alveolar basal epithelial cells (A549 etc.) are ALI-exposed to fresh, diluted (1:40-1:100) combustion aerosols and subsequently were toxicologically and molecular-biologically characterized. Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling to characterise the cellular responses. The HFO ship emissions contained high concentrations of toxic compounds (transition metals, organic toxicants) and particle masses. The cellular responses included inflammation and oxidative stress. Surprisingly, the DF ship emissions, which predominantly contain rather "pure" carbonaceous soot and much less known toxicants, induced significantly broader biological effects, affecting essential cellular pathways (e.g., mitochondrial function and intracellular transport). Therefore the use of distillate fuels for shipping (this is the current emission reduction strategy of the IMO) appears insufficient for diminishing health effects. The study suggests rather reducing the particle emissions

  5. Chemical Composition of Ground Pearl (Eurhizococcus colombianus Cysts

    Directory of Open Access Journals (Sweden)

    Fernando Echeverri

    2008-01-01

    Full Text Available Ground pearl (Eurhizococcus colombianus is a crop pest in Colombia, withspecial impact on fig, grass, rubus and tomato plants. The insect is resistant to externalinsecticide application because it produces a thick waxy shell that isolates it from theenvironment. The composition of this shell was determined by NMR and MS as atriglyceride, whose fatty acid is transformed into other products with the metamorphosis ofthe insect. Additionally, several enzymatic inhibitors were assayed to control the insectwith negative results.

  6. Impact Damage of 3D Orthogonal Woven Composite Circular Plates

    Science.gov (United States)

    Ji, Changgan; Sun, Baozhong; Qiu, Yiping; Gu, Bohong

    2007-11-01

    The damages of 3D orthogonal woven composite circular plate under quasi-static indentation and transverse impact were tested with Materials Test System (MTS) and modified split Hopkinson bar (SHPB) apparatus. The load vs. displacement curves during quasi-static penetration and impact were obtained to study the energy absorption of the composite plate. The fluctuation of the impact stress waves has been unveiled. Differences of the load-displacement curves between the quasi-static and impact loading are discussed. This work also aims at establishing a unit-cell model to analyze the damage of composites. A user material subroutine which named VUMAT for characterizing the constitutive relationship of the 3-D orthogonal woven composite and the damage evolution is incorporated with a finite element code ABAQUS/Explicit to simulate the impact damage process of the composite plates. From the comparison of the load-displacement curves and energy absorption curves of the composite plate between experimental and FEM simulation, it is shown that the unit-cell model of the 3D woven composite and the VUMAT combined with the ABAQUS/Explicit can calculate the impact responses of the circular plate precisely. Furthermore, the model can also be extended to simulate the impact behavior of the 3D woven composite structures.

  7. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H2SO4 and CaCl2. Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H2SO4 and CaCl2; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites.

  8. Numerical analysis of impact behaviour on aeronautical composite protections

    OpenAIRE

    Portilla Bullido, Alberto

    2011-01-01

    In this project, a complete study of impacts against protection composite materials is presented, taking into account all parameters involved in the process: from the organic fibre that is part of the composite, to the projectile impacting on the protection panels. The project was done during an internship in the department of Structural Dynamics and Aeroelasticity at Airbus Military (EADS-CASA), therefore most of the impacts studied here are typical from aeronautics industry. During the impa...

  9. Analytical Scanning and Transmission Electron Microscopy of Laboratory Impacts on Stardust Aluminium Foils: Interpreting Impact Crater Morphology and the Composition of Impact Residues.

    Energy Technology Data Exchange (ETDEWEB)

    Kearsley, A T; Graham, G A; Burchell, M J; Cole, M J; Dai, Z R; Teslich, N; Chater, R; Wozniakiewicz, P A; Spratt, J; Jones, G

    2006-10-19

    The known encounter velocity (6.1kms{sup -1}) between the Stardust spacecraft and the dust emanating from the nucleus of comet Wild 2 has allowed realistic simulation of dust collection in laboratory experiments designed to validate analytical methods for the interpretation of dust impacts on the aluminium foil components of the Stardust collector. In this report we present information on crater gross morphology, the pre-existing major and trace element composition of the foil, geometrical issues for energy dispersive X-ray analysis of the impact residues in scanning electron microscopes, and the modification of dust chemical composition during creation of impact craters as revealed by analytical transmission electron microscopy. Together, these observations help to underpin the interpretation of size, density and composition for particles impacted upon the Stardust aluminium foils.

  10. Impact of maritime transport on particulate matter concentrations and chemical compositions in four port-cities of the Adriatic/Ionian area: an overview of the results of POSEIDON project

    Science.gov (United States)

    Contini, Daniele; Gambaro, Andrea; Argiriou, Athanasios; Alebic-Juretic, Ana; Barbaro, Elena; Cesari, Daniela; Dimopoulos, Spiros; Dinoi, Adelaide; Donateo, Antonio; Gregoris, Elena; Karagiannidis, Athanasios; Ivosevic, Tatjana; Liora, Natalia; Melas, Dimitrios; Merico, Eva; Mifka, Boris; Orlic, Ivo; Poupkou, Anastasia; Sarovic, Kristina

    2015-04-01

    Pollutant emissions from ships and harbour activities constitute an important source of pollution of coastal areas with potential influences on the climate and the health of their inhabitants. A recent review (Viana et al., 2014) shows that these emissions could have an important impact on the Mediterranean and that there is a lack of data for the Eastern and South-Eastern part of this area. This work presents an analysis of the impact of ship emissions to atmospheric particle concentrations (PM) in four important port-cities (Patras Greece, Brindisi and Venice Italy, and Rijeka Croatia) of the Adriatic/Ionian area. The study was performed within the POSEIDON project (Pollution monitoring of ship emissions: an integrated approach for harbours of the Adriatic basin, funded within the MED Programme 2007-2013). The study uses an integrated approach using emission inventories, dispersion modelling and measurements taken at high temporal resolution (1 min) and low temporal resolution for chemical characterization of PM. The emission inventories of the four port-cities show that ships contribute between 11.7% and 31.0% of the total PM emissions being a source locally comparable with road traffic (ranging between 11.8% and 26.6%). The source apportionment using the receptor model PMF showed an oil combustion source (that includes ship emissions), characterized by V and Ni, in Brindisi, Venice and Rijeka with V/Ni ratio ranging between 1.4 and 4.2 indicating local differences in chemical profiles of the emissions. The V concentrations were used to evaluate the contributions of primary ship emissions to PM (Agrawal et al., 2009) that resulted between 1.3% and 2.8%. The contribution to secondary sulphate was 11% of PM2.5 in Brindisi (Cesari et al., 2014). The analysis of high-temporal resolution measurements taken near the harbour areas of Venice, Patras and Brindisi showed a contribution of ship emissions to PM2.5 varying between 3.5% and 7.4%. The relative contribution to

  11. A bootstrap estimation scheme for chemical compositional data with nondetects

    Science.gov (United States)

    Palarea-Albaladejo, J; Martín-Fernández, J.A; Olea, Ricardo A.

    2014-01-01

    The bootstrap method is commonly used to estimate the distribution of estimators and their associated uncertainty when explicit analytic expressions are not available or are difficult to obtain. It has been widely applied in environmental and geochemical studies, where the data generated often represent parts of whole, typically chemical concentrations. This kind of constrained data is generically called compositional data, and they require specialised statistical methods to properly account for their particular covariance structure. On the other hand, it is not unusual in practice that those data contain labels denoting nondetects, that is, concentrations falling below detection limits. Nondetects impede the implementation of the bootstrap and represent an additional source of uncertainty that must be taken into account. In this work, a bootstrap scheme is devised that handles nondetects by adding an imputation step within the resampling process and conveniently propagates their associated uncertainly. In doing so, it considers the constrained relationships between chemical concentrations originated from their compositional nature. Bootstrap estimates using a range of imputation methods, including new stochastic proposals, are compared across scenarios of increasing difficulty. They are formulated to meet compositional principles following the log-ratio approach, and an adjustment is introduced in the multivariate case to deal with nonclosed samples. Results suggest that nondetect bootstrap based on model-based imputation is generally preferable. A robust approach based on isometric log-ratio transformations appears to be particularly suited in this context. Computer routines in the R statistical programming language are provided. 

  12. INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

    Directory of Open Access Journals (Sweden)

    Saman GHAHRI

    2014-03-01

    Full Text Available In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP composites was investigated. The PP (virgin and recycled polypropylene and wood flour (WF were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA and ethylene/propylene/diene terpolymer (EPDM, to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier. The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites

  13. Chemical composition of the sediment from Lake 20 (Antarctica

    Directory of Open Access Journals (Sweden)

    Daria ROSSI

    2000-02-01

    Full Text Available Lake 20 (19,000 m2 is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention of using this information to contribute to a better understanding of the processes involved in the long range transport of pollutants and their role in global changes. A sediment core from Lake 20 (Antarctica, 18 cm long, was collected in 1994, sliced into 2 cm sections and analysed using X Ray fluorescence spectrometry for 17 elements (Si, Al, Ca, K, Fe, Mg, Ti, S, P, Pb, Zn, Cu, Ni, Mn, Cr, Na, Cl, by CHN Elemental Analyser for C and N, by Flameless Atomic Absorption Spectrometry for As, and by Cold Vapour Atomic Absorption Spectrometry for Hg. The chemical composition of the sediments is consistent with the known geochemical characteristics of the drainage basin. While the chemical analyses reveal that sedimentation in Lake 20 has changed through time, the variations along the core are most probably related to the climatic evolution of the area, to the consequent changes in weathering processes, and possibly to an increase in the primary productivity of the lake, rather than to anthropogenic influences on the biogeochemical cycles of the elements.

  14. The Impact of Price on Chemical Fertilizer Demand in China

    Institute of Scientific and Technical Information of China (English)

    John K.Dagsvik

    2012-01-01

    Since 1998,the national policies on chemical fertilizer in China have been concentrated in limiting price plus subsidizing,abolishing agricultural tax,giving direct subsidies to farmers,and other aspects.In order to analyze the impact of national policies on the consumption of chemical fertilizer,this article selects the consumption of chemical fertilizer per unit,chemical fertilizer price index and farmers’net income in different provinces during the period 1998-2007 as variables,to conduct regression analysis of chemical fertilizer expenditure function,and calculate the price elasticity and income elasticity of chemical fertilizer demand in different provinces over the decade based on the regression results.The results show that at present the basic consumption of chemical fertilizer for agricultural development in China is 0.35 t/hm 2 ,and the consumption of chemical fertilizer is excessive in some provinces;the chemical fertilizer market has not been really established,and the price has little impact on demand.This indicates that the chemical fertilizer is essential for agricultural economic development,and it increases along with the increase of farmers’income; the intervention of the national policy in chemical fertilizer price is a fundamental reason for the rising demand for chemical fertilizer.This also to some extent indicates that the policy effect of merely using environmental taxes to change farmers’consumption of chemical fertilizer is limited;there is a need to transform the existing policies purely promoting agricultural economic development,toward giving different subsidies in accordance with whether the farmers’fertilization pattern is beneficial to the environment.

  15. Impact Performance of 3D Integrated Cellular Woven Composite Panel

    Institute of Scientific and Technical Information of China (English)

    TIAN Wei; ZHU Cheng-yan

    2006-01-01

    This paper studied the impact resistance of 3D integrated cellular woven composite panel under persudo-static impact,comprised the test result with property of typical 3D woven composites, analyzed some parameters that maybe affect composites' impact resistance and at last used SEM to observe the damage process and mechanism of samples. The result shows that the impact resistance of 3D integrated cellular woven composites is much better than the performance of typical 3D woven composites; it is an active method to improve the impact resistance of composites that developing preform with cellular on the basis of typical 3D woven structure; for different 3D integrated cellular woven structure, the value of absorbed-energy is incrensing with the hollow percentage; tiny deformation will not emerge on samples until the acting force gets to 85% of the maximum;similar with typical 3D woven composites, the delaminated phenomenon of 3D integrated cellular woven composites is also unapparent during impact process.

  16. Dynamics of the chemical composition of rainwater throughout Hurricane Irene

    Directory of Open Access Journals (Sweden)

    K. M. Mullaugh

    2013-03-01

    Full Text Available 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.

  17. Assessment of kidney stone and prevalence of its chemical compositions.

    Science.gov (United States)

    Pandeya, A; Prajapati, R; Panta, P; Regmi, A

    2010-09-01

    Kidney stone analysis is the test done on the stone which cause problems when they block the flow of urine through or out of the kidneys. The stones cause severe pain and are also associated with morbidity and renal damage. There is also no clear understanding on the relative metabolic composition of renal calculi. Hence, the study is aimed to find out the chemical composition of it which can guide treatment and give information that may prevent more stones from forming. The study was carried out on the stones that had been sent to the department of Biochemistry (n = 99; M = 61; F = 38; Mean age: 33.6 +/- 14.4 years) Approximately 98.9% of stones were composed of oxalate, 95.9% of Calcium, 85.8% of phosphate, 62.6% of Urate, 46.4% of Ammonium and very few percentages of Carbonate.

  18. Chemical composition of lipophilic extractives from grey alder (Alnus incana

    Directory of Open Access Journals (Sweden)

    Oskars Bikovens

    2013-02-01

    Full Text Available The chemical composition of the lipophilic extractives in the hexane extracts from grey alder bark, knotwood, and cones has been investigated by gas chromatography and gas chromatography-mass spectrometry. The efficiency of two extraction methods was compared. The highest amount of lipophilic extractives (about 9% of o.d. material was observed in grey alder cone, while the lowest (about 3% was found in knotwood. The three different morphological parts of alder showed significant differences not only in the content but also in composition of extractives, namely fatty acids, triglycerides, and triterpenes. The main identified compounds were triterpenoids (lupen-3-one, lupeol, betulone, betulinol, and betulinic acid in bark, and triglycerides in cones. The major group in knotwood was free fatty acids (mainly linoleic acid, 18:2.

  19. Chemical composition and health effects of Tartary buckwheat.

    Science.gov (United States)

    Zhu, Fan

    2016-07-15

    Tartary buckwheat (Fagopyrum tataricum) contains a range of nutrients including bioactive carbohydrates and proteins, polyphenols, phytosterols, vitamins, carotenoids, and minerals. The unique composition of Tartary buckwheat contributes to their various health benefits such as anti-oxidative, anti-cancer, anti-hypertension, anti-diabetic, cholesterol-lowering, and cognition-improving. Compared with the more widely cultivated and utilised common buckwheat (F. esculentum), Tartary buckwheat tends to contain higher amounts of certain bioactive components such as rutin, therefore, showing higher efficiency in preventing/treating various disorders. This review summarises the current knowledge of the chemical composition of Tartary buckwheat, and their bio-functions as studied by both in vitro and in vivo models. Tartary buckwheat can be further developed as a sustainable crop for functional food production to improve human health.

  20. Analysis of chemical composition of high viscous oils

    Directory of Open Access Journals (Sweden)

    Irina Germanovna Yashchenko

    2014-07-01

    Full Text Available The spatial distribution of viscous oils which are considered as an important reserve for oil-production in future were studied on base of information from global database on oil physical and chemical properties. Changes in chemical composition of viscous oils in different basins and continents were analyzed as well. It is shown, on average, viscous oils are sulfur-bearing, low paraffin, highly resinous oils with an average content of asphaltenes and low content of the fraction boiling at 200 C. Study results of viscous oils peculiarities of Canada, Russia and Venezuela are given. The analysis results can be used to determine the optimal layouts and conditions of oil transportation, to improve the search methods of geochemical exploration, and to solve other problems in the oil chemistry.

  1. Nepheline structural and chemical dependence on melt composition

    Energy Technology Data Exchange (ETDEWEB)

    Marcial, José; Crum, Jarrod; Neill, Owen; McCloy, John

    2016-02-01

    Nepheline crystallizes upon slow-cooling in some melts concentrated in Na2O and Al2O3, which can result in a residual glass phase of low chemical durability. Nepheline can incorporate many components often found in high-level waste radioactive borosilicate glass, including glass network ions (e.g., Si, Al, Fe), alkali metals (e.g., Cs, K, Na, and possibly Li), alkaline-earth metals (e.g., Ba, Sr, Ca, Mg), and transition metals (e.g., Mn, and possibly Cr, Zn, Ni). When crystallized from melts of different compositions, nepheline chemistry varies as a function of starting glass composition. Five simulated high level nuclear waste borosilicate glasses shown to crystallize large fractions of nepheline on slow cooling, were selected for study. These melts constituted a range of Al2O3, B2O3, CaO, Na2O, K2O, Fe2O3, and SiO2 compositions. Compositional analyses of nepheline crystals in glass by electron probe micro-analysis (EPMA) indicate that boron is unlikely to be present in any significant concentration, if at all, in nepheline. Also, several models are presented for calculating the fraction of vacancies in the nepheline structure.

  2. Chemical composition and fatty acid contents in farmed freshwater prawns

    Directory of Open Access Journals (Sweden)

    Carolina de Gasperi Portella

    2013-08-01

    Full Text Available The objective of this work was to evaluate the chemical composition and fatty acid contents of Amazonian and giant river prawns. After four-month farming, with the same diet for both species, palmitic and stearic acids were the main saturated fatty acids. Oleic acid was the main monounsatured fatty acid, and the eicosapentaenoic and docosahexaenoic acids were the most abundant polyunsaturated acids. Amazonian prawn has higher levels of protein and polyunsaturated fatty acids than those of the giant river prawn, which shows its potential for aquaculture.

  3. Chemical composition and quality of sweet sorghum and maize silages

    OpenAIRE

    Zbigniew PODKÓWKA; Lucyna PODKÓWKA

    2011-01-01

    Sweet sorghum (Sorghum saccharatum) silage, maize (Zea mays) silage, and sorghum and maize (1:1) silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88%) in sorghum silage and the highest (37.45%) in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre an...

  4. Stevia rebaudiana Bertoni - chemical composition and functional properties.

    Science.gov (United States)

    Marcinek, Katarzyna; Krejpcio, Zbigniew

    2015-01-01

    Sweetleaf (Stevia rebaudiana Bertoni), currently investigated by many researchers, has been known and used for more than a thousand years indigenous tribes of South America, who called it "kaa-hee" ("sweet herb"). Thanks to its chemical composition and processability sweetleaf may be an alternative for synthetic sweeteners. Nutritional and health-promoting aspects of Stevia rebaudiana are presently being studied in many research centres. The aim of this study is to present nutritional and health-promoting value of the still-little known sweetleaf.

  5. Stevia rebaudiana Bertoni – chemical composition and functional properties

    Directory of Open Access Journals (Sweden)

    Katarzyna Marcinek

    2015-06-01

    Full Text Available Sweetleaf (Stevia rebaudiana Bertoni, currently investigated by many researchers, has been known and used for more than a thousand years indigenous tribes of South America, who called it “kaa-hee” (“sweet herb”. Thanks to its chemical composition and processability sweetleaf may be an alternative for synthetic sweeteners. Nutritional and health-promoting aspects of Stevia rebaudiana are presently being studied in many research centres. The aim of this study is to present nutritional and health-promoting value of the still-little known sweetleaf.

  6. Public Health Risk Conditioned by Chemical Composition of Ground Water

    Science.gov (United States)

    Yankovich, E.; Osipova, N.; Yankovich, K.; Matveenko, I.

    2016-03-01

    The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

  7. Chemical composition of water from roofs in Gdansk, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Tsakovski, Stefan, E-mail: stsakovski@chem.uni-sofia.b [Chair of Physical Chemistry, Faculty of Chemistry, University of Sofia, J Bourchier Blvd. 1, 1164 Sofia (Bulgaria); Tobiszewski, Marek [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Simeonov, Vasil, E-mail: vsimeonov@chem.uni-sofia.b [Chair of Analytical Chemistry, Faculty of Chemistry, University of Sofia, 1164 Sofia (Bulgaria); Polkowska, Zaneta [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Namiesnik, Jacek, E-mail: chemanal@pg.gda.p [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland)

    2010-01-15

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

  8. Chemical composition and larvicidal activity of Rollinia leptopetala (Annonaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, Edinilza M.A.; Arriaga, Angela M.C.; Lemos, Telma L.G.; Oliveira, M. Conceicao F. de; Vasnconcelos, Jackson Nunes e; Lima, Jefferson Q.; Malcher, Grazielle T. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: angelamcarriaga@yahoo.com.br; Santiago, Gilvandete M.P. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Farmacia; Nascimento, Ronaldo F. do [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Analitica e Fisico-Quimica; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacases, RJ (Brazil). Setor de Quimica de Produtos Naturais. Lab. de Ciencias Quimicas

    2009-07-01

    The aim of present study was to describe the chemical composition of the essential oils from the leaf and stem of Rollinia leptopetala R. E. Fries (Annonaceae) and to evaluate the larvicidal activities of these essential oils, of the methanol extract from roots of this plant and of the oxoaporphine alkaloid, liriodenine (1) against the third-instar of Aedes aegypti larvae. The methanol extract from the roots showed larvicidal activity with LC{sub 50} 64.6 {+-} 1.5 ppm. Higher activity was observed for the isolated alkaloid liriodenine (1), LC{sub 50} 3.6 {+-} 0.4 ppm. The essential oils from the leaves and stems, also exhibited larvicidal activity with LC{sub 50} 104.7 {+-} 0.2 and 34.7 {+-} 0.3 ppm, respectively. These results suggest R. leptopetala as a source of natural larvicidal compounds. This is the first report about the chemical composition and larvicidal activity of the leaf and stem essential oils of R. leptopetala. (author)

  9. Influence of Material Distribution on Impact Resistance of Hybrid Composites

    Science.gov (United States)

    Abatan, Ayu; Hu, Hurang

    1998-01-01

    Impact events occur in a wide variety of circumstances. A typical example is a bullet impacting a target made of composite material. These impact events produce time-varying loads on a structure that can result in damage. As a first step to understanding the damage resistance issue in composite laminates, an accurate prediction of the transient response during an impact event is necessary. The analysis of dynamic loadings on laminated composite plates has undergone considerable development recently. Rayleigh-Ritz energy method was used to determine the impact response of laminated plates. The impact response of composite plates using shear deformation plate theory was analyzed. In recent work a closed-form solution was obtained for a rectangular plate with four edges simply supported subjected to a center impact load using classical plate theory. The problem was further investigated and the analysis results compared of both classical plate theory and shear deformation theory, and found that classical plate theory predicts very accurate results for the range of small deformations considered. In this study, the influence of cross sectional material distribution on the comparative impact responses of hybrid metal laminates subjected to low and medium velocity impacts is investigated. A simple linear model to evaluate the magnitude of the impact load is proposed first, and it establishes a relation between the impact velocity and the impact force. Then a closed-form solution for impact problem is presented. The results were compared with the finite element analysis results. For an 11 layer-hybrid laminate, the impact response as a function of material distribution in cross-section is presented. With equal areal weight, the effect of the number of laminate layers on the impact resistance is also investigated. Finally, the significance of the presented results is discussed.

  10. Anthropogenic and impact spherules: Morphological similarity and chemical distinction – A case study from India and its implications

    Indian Academy of Sciences (India)

    Ambalika Niyogi; Jayanta K Pati; Suresh C Patel; Dipak Panda; Shiv K Patil

    2011-12-01

    This paper provides first report of silica-rich anthropogenic spherules of varying colour, shape, size, surface texture and chemical composition found in road-deposited sediments (RDS) of Allahabad city, Uttar Pradesh, India. Morphological details and lithophile elemental composition of the silica-rich spherules are compared to microtektites and impact spherules from India to demonstrate their striking morphological similarities and chemical variability. This study suggests the need to use spherule data carefully while assigning an impact origin to spherule-finds or spherule-bearing lithological horizons.

  11. Impact resistance of hybrid composite fan blade materials

    Science.gov (United States)

    Friedrich, L. A.

    1974-01-01

    Improved resistance to foreign object damage was demonstrated for hybrid composite simulated blade specimens. Transply metallic reinforcement offered additional improvement in resistance to gelatin projectile impacts. Metallic leading edge protection permitted equivalent-to-titanium performance of the hybrid composite simulated blade specimen for impacts with 1.27 cm and 2.54 cm (0.50 and 1.00 inch) diameter gelatin spheres.

  12. Impact of the electrochemical porosity and chemical composition on the lithium ion exchange behavior of polypyrroles (ClO4-, TOS-, TFSI-) prepared electrochemically in propylene carbonate. comparative EQCM, EIS and CV studies.

    Science.gov (United States)

    Dziewoński, Paweł Marek; Grzeszczuk, Maria

    2010-06-03

    Conditions of electrodeposition, i.e. a potential window of the process, addition of water, the current density, and morphology of substrate electrodes (Pt, Pt/TiO(2), Au), were shown to influence strongly ion-exchange properties of polypyrrole (PPy) synthesized in propylene carbonate (PC), doped with ClO(4)(-) or p-toluenesulfonate (TOS(-)). "Electrochemical porosity" and redox activity of PPy films were compared to the characteristics of poly(3,4-ethylenedioxythiophene) (PEDOT). A molecular indicator of the PPy film structure packing was bis(trifluoromethylsulfonyl)imide anion (TFSI(-)). Ion-exchange properties of PPy were found to be almost independent of chemical composition of the polymer, described in the literature as PPy(I), PPy(II), PPy(III). Instead, micro- and nanoscopic morphology of the polymer film and a molecular level packing of the polymer chains as well as the counterion nature are of the foremost importance. The polymer film structure/properties are shown to change upon prolonged redox/ionic stimulations. Lithium exchange between PPy films and contacting phases (PC electrolyte, TiO(2)) proceeds in addition to the anion exchange, the latter being a dominant process under conditions of the reversible electrochemical p-doping of PPy, although diffusion coefficients of PC solvated lithium ions in PPy are higher than diffusion coefficients of perchlorate, p-toluenesulfonate or bis(trifluoromethylsulfonyl)imide anions. The highest flux of Li(+) ions into/out of the PPy phase takes place about -1.0 V vs Ag/Ag(+) which is clearly evidenced by the cathodic/anodic CV peaks. Cation transport phenomena can be analyzed independently from anion transport when observed at a longer time scale (low values of potential scan rate) as each prevails at different redox states of the polymer. However, in a shorter time scale (v > or = 10 mV s(-1)), the opposite fluxes of cations and anions were observed to interfere. Furthermore, a net uptake of propylene carbonate by

  13. Chemical Composition of the Essential Oil from Chaerophyllum temulum (Apiaceae).

    Science.gov (United States)

    Stamenković, Jelena G; Stojanović, Gordana S; Radojković, Ivana R; Petrović, Goran M; Zlatković, Bojan K

    2015-08-01

    The present study reports the chemical composition on the essential oil obtained from fresh roots, stems, inflorescences and fruits of Chaerophyllum temulum. In all samples, except the roots, the most dominant components were sesquiterpene hydrocarbons. (Z)-Falcarinol was the principal constituent of the root essential oils (61.7% at the flowering stage and 62.3% at the fruiting stage). The blossom oil was dominated by (Z,E)-α-famesene (23.4%), (E)-β-farnesene (9.0%) and germacrene D-4-ol (9%), whereas the oil from the fruit had germacrene D-4-ol (27.6%) as its main compound, accompanied by (Z,E)-α-famesene (13.4%). Germacrene D was the most abundant component of the stem essential oil (38.4% at the flowering stage and 32.5% at the fruiting stage). The obtained results show that the qualitative composition of the oil depends on the part of the plant which is analyzed, while the quantitative composition of the main components depends on the growing stage of the plant.

  14. Transport composite fuselage technology: Impact dynamics and acoustic transmission

    Science.gov (United States)

    Jackson, A. C.; Balena, F. J.; Labarge, W. L.; Pei, G.; Pitman, W. A.; Wittlin, G.

    1986-01-01

    A program was performed to develop and demonstrate the impact dynamics and acoustic transmission technology for a composite fuselage which meets the design requirements of a 1990 large transport aircraft without substantial weight and cost penalties. The program developed the analytical methodology for the prediction of acoustic transmission behavior of advanced composite stiffened shell structures. The methodology predicted that the interior noise level in a composite fuselage due to turbulent boundary layer will be less than in a comparable aluminum fuselage. The verification of these analyses will be performed by NASA Langley Research Center using a composite fuselage shell fabricated by filament winding. The program also developed analytical methodology for the prediction of the impact dynamics behavior of lower fuselage structure constructed with composite materials. Development tests were performed to demonstrate that the composite structure designed to the same operating load requirement can have at least the same energy absorption capability as aluminum structure.

  15. Chemical composition of the circumstellar disk around AB Aurigae

    CERN Document Server

    Pacheco-Vázquez, S; Agúndez, M; Pinte, C; Alonso-Albi, T; Neri, R; Cernicharo, J; Goicoechea, J R; Berné, O; Wiesenfeld, L; Bachiller, R; Lefloch, B

    2015-01-01

    Aims. Our goal is to determine the molecular composition of the circumstellar disk around AB Aurigae (hereafter, AB Aur). AB Aur is a prototypical Herbig Ae star and the understanding of its disk chemistry is of paramount importance to understand the chemical evolution of the gas in warm disks. Methods. We used the IRAM 30-m telescope to perform a sensitive search for molecular lines in AB Aur as part of the IRAM Large program ASAI (A Chemical Survey of Sun-like Star-forming Regions). These data were complemented with interferometric observations of the HCO+ 1-0 and C17O 1-0 lines using the IRAM Plateau de Bure Interferometer (PdBI). Single-dish and interferometric data were used to constrain chemical models. Results. Throughout the survey, several lines of CO and its isotopologues, HCO+, H2CO, HCN, CN and CS, were detected. In addition, we detected the SO 54-33 and 56-45 lines, confirming the previous tentative detection. Comparing to other T Tauri's and Herbig Ae disks, AB Aur presents low HCN 3-2/HCO+ 3-2 ...

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

    Science.gov (United States)

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

    1980-01-01

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

  17. Laboratory analogues simulating Titan's atmospheric aerosols: Compared chemical compositions of grains and thin films

    Science.gov (United States)

    Carrasco, Nathalie; Jomard, François; Vigneron, Jackie; Etcheberry, Arnaud; Cernogora, Guy

    2016-09-01

    Two sorts of solid organic samples can be produced in laboratory experiments simulating Titan's atmospheric reactivity: grains in the volume and thin films on the reactor walls. We expect that grains are more representative of Titan's atmospheric aerosols, but films are used to provide optical indices for radiative models of Titan's atmosphere. The aim of the present study is to address if these two sorts of analogues are chemically equivalent or not, when produced in the same N2-CH4 plasma discharge. The chemical compositions of both these materials are measured by using elemental analysis, XPS analysis and Secondary Ion Mass Spectrometry. The main parameter probed is the CH4/N2 ratio to explore various possible chemical regimes. We find that films are homogeneous but significantly less rich in nitrogen and hydrogen than grains produced in the same experimental conditions. This surprising difference in their chemical compositions could be explained by the efficient etching occurring on the films, which stay in the discharge during the whole plasma duration, whereas the grains are ejected after a few minutes. The higher nitrogen content in the grains possibly involves a higher optical absorption than the one measured on the films, with a possible impact on Titan's radiative models.

  18. Effect of chemical composition of sheep’s milk on the chemical composition of Livno and Travnik cheese

    Directory of Open Access Journals (Sweden)

    Amina Hrković

    2011-06-01

    Full Text Available Bosnia and Herzegovina has a centuries-old tradition in the family dairy products, among which 2-3 types of cheeses dominate. Well known dairy products in BiH are indigenous Livno and Travnik cheese, a group of cheeses produced from thermally untreated raw sheep milk. The aim of this study was assessing the effects of certain parameters on the chemical composition of the milk composition of indigenous cheeses - Livno and Travnik. Two manufacturers within two different locations (Livno and Travnik during summer grazing of sheep, were selected for this research. The study included 117sheep (Livno 57 sheep, Travnik 60 sheep. The cheese milk was used for determination of fat, protein and lactose content. Six samples were taken from obtained cheeses: 3 samples of Livno and 3samples of Travnik cheese, which means one for each sampling period. In cheese dry matter content, water, fat, fat in dry matter and acidity (pH were determined, and then correlation between the constituents of milk and cheese ingredients content was set. The most common causes of such phenomenon is non-standard production, storage and ripening. On Travnik area, the content of fat and milk protein varied according to sampling period, which can be attributed to the already mentioned diet and stage of lactation. At the same time the protein content decreased mainly by the end of lactating period. Lactose content has proven to be the most stable parameter of milk. In both investigated cheese samples slightly higher water content was found compared to normal values for these two local cheese, while the proportion of fat and dry matter varied within the sampling period. Variation of certain parameters of the chemical composition of investigated samples of Livno and Travnik cheese, as well as their correlation with parameters of milk is primarily a consequence of changing the chemical composition of milk as the basic raw materials and/or significant variations in technology that could

  19. Low-Velocity Impact on Composite Sandwich Plates

    Science.gov (United States)

    1996-07-01

    plate and correct for this error. 3.4 One- and Two-Degree of Freedom Models A single degree of freedom system (figure 3-3a) was used by Caprino et al...Composite Materials, Vol. 26, No. 10: 1523-1535 (1992). 211) Caprino , G., and Teti, R. "Impact and post-impact behavior of foam core sandwich

  20. The Impact of Flow Injection on Modern Chemical Analysis

    DEFF Research Database (Denmark)

    Hansen, Elo Harald

    There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA-publications in i......There is no doubt that Flow Injection Analysis (FIA) has had a profound impact on the ways and means that modern analytical chemical procedures are performed. This is amply reflected in the voluminous scientific literature, which by the middle of 2004 passed more than 14,500 FIA...... and preconcentration procedures. In recent years, FIA has been supplemented by Sequential Injection Analysis (SIA) and the Lab-on-Valve (LOV) approach. Following a brief historic introduction and an account of the impact of FIA in academia, the lecture will describe these two new generations of FIA, accompanied...

  1. Antimicrobial activity of Iranian propolis and its chemical composition

    Directory of Open Access Journals (Sweden)

    Yaghoubi M.J.

    2007-04-01

    Full Text Available The objective of this study was to investigate the antimicrobial activity of ethanol extract of Iranian propolis on some microorganisms using disc diffusion method. The chemical composition of the propolis was also investigated using thin layer chromatography and spectrophotometric methods. Ethanol extract of propolis showed activity only against Gram-positives and fungi, whereas no activity was observed against Gram-negatives. Thin layer chromatography screening revealed the presence of pinocembrine, caffeic acid, kaempferol, phenethyl caffeate, chrysin, and galangin in Iranian propolis. The total flavonoid and phenolic contents were 7.3% and 36%, respectively, which suggests that the strong antimicrobial activity of Iranian propolis may be due to high levels of phenolic and flavonoid compounds.

  2. Chemical vapor infiltration of TiB{sub 2} composites

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    This program is designed to develop a Hall-Heroult aluminum smelting cathode with substantially improved properties. The carbon cathodes in current use require significant anode-to-cathode spacing in order to prevent shorting, causing significant electrical inefficiencies. This is due to the non-wettability of carbon by aluminum which causes instability in the cathodic aluminum pad. It is suggested that a fiber reinforced-TiB{sub 2} matrix composite would have the requisite wettability, strength, strain-to-failure, cost, and lifetime to solve this problem. The approach selected to fabricate such a cathode material is chemical vapor infiltration (CVI). This program is designed to evaluate potential fiber reinforcements, fabricate test specimens, and test the materials in a static bath and lab-scale Hall cell.

  3. Thymus vulgaris essential oil: chemical composition and antimicrobial activity.

    Science.gov (United States)

    Borugă, O; Jianu, C; Mişcă, C; Goleţ, I; Gruia, A T; Horhat, F G

    2014-01-01

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

  4. Chemical composition of Chenopodium botrys L. (Chenopodiaceae essential oil

    Directory of Open Access Journals (Sweden)

    Ljubica Adji Andov

    2014-08-01

    Full Text Available Chemical composition of essential oil isolated from aerial parts of Chenopodium botrys L. (Chenopodiaceae collected from five different locations in the Republic of Macedonia was analysed by GC/FID/MS. Seventy five compounds were identified representing 90.02- 91.24% of the oil. The analysis has shown that the oils were rich in sesquiterpenе components (83.18-87.54% comprising elemol acetat (9.88%-21.98%, seline-11-en-4α-ol (9.81%-13.5%, selina-3,11-dien-6α-ol (6.42%-9.71% and elemol (5.57%-9.49% as major oxygen containing sesquiterpenes, followed by lower content of α-eudesmol acetat (3.24%-4.11%, α-chenopodiol (2.42%-5.43%, botrydiol (1.87-5.73% and α-chenopodiol-6-acetat (1.9%-4.73%.

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

    Directory of Open Access Journals (Sweden)

    A. J. van Beelen

    2013-06-01

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

  6. Parametric studies on self-repairing approaches for resin infused composites subjected to low velocity impact

    Science.gov (United States)

    Motuku, M.; Vaidya, U. K.; Janowski, G. M.

    1999-10-01

    Low velocity impact response of glass reinforced polymer composites, which have the potential to self-repair both micro- and macro-damage, has been investigated. This class of material falls under the category of passive smart polymer composites. The self-repairing mechanism is achieved through the incorporation of hollow fibers in addition to the normal solid reinforcing fibers. The hollow fibers store the damage-repairing solution or chemicals that are released into the matrix or damaged zone upon fiber failure. Plain-weave S-2 glass fabric reinforcement, vinyl ester 411-C50 and EPON-862 epoxy resin systems were considered for this study. Different tubing materials were investigated for potential use as storage materials for the repairing chemicals instead of the actual hollow repair fibers and included borosilicate glass micro-capillary pipets, flint glass pasteur pipets, copper tubing and aluminum tubing. composite panels were fabricated by using a vacuum assisted resin transfer molding process. The present investigation addressed fabrication of self-repairing composite panels and some of the parameters that influence the response of self-repairing composites to impact loading. Specific issues addressed by this study include: the processing quality; the selection of storage material for the repairing solution; release and transportation of the repairing solution; the effect of the number, type and spatial distribution of the repairing tubes, specimen thickness, matrix material and impact energy level.

  7. Impact loading of an aluminum/alumina composite

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.N.; Hixson, R.S.; Gray, G.T. III

    1994-02-01

    The combined demands of increased strength and reduced weight in modern dynamic structural applications require improved understanding of composite materials subject to impact conditions. In order to isolate and identify individual contributions to composite material behavior under these conditions, an experimental and theoretical program was undertaken to examine dynamic behavior of an aluminum/alumina composite consisting of a 6061-T6 aluminum matrix containing elastic, spherical Al{sub 2}O{sub 3} inclusions (10 percent by volume, average diameter {approximately}25 microns). Parallel impact experiments are conducted on these composites and on pure 6061-T6 aluminum samples. This combination provides a direct and immediate qualitative picture of the effect of Al{sub 2}O{sub 3} inclusions the dynamic response of the composite in compression, release, and spallation. Additional experimental information is provided by post-shock reload tests of shock-recovered samples at quasi-static and intermediate strain rates.

  8. Chemical Composition of Iran's Pistacia atlantica Cold-Pressed Oil

    Directory of Open Access Journals (Sweden)

    M. Saber-Tehrani

    2013-01-01

    Full Text Available The lipid fraction of Pistacia atlantica seeds was extracted for the first time by means of cold-press technique and analyzed for its chemical composition. The fatty acids, sterols, triacylglycerols (TAG, tocopherols, polyphenols, and pigments were identified and their concentrations were determined by means of reversed-phase high-performance liquid chromatography (RP-HPLC and gas chromatography (GC. Because of its high content of unsaturated fatty acids, it might prove to be of value in diets and it may be used as edible cooking or salad oils or for margarine manufacture. Pistacia atlantica seed oil has the unique sterols and tocopherols content providing source of natural antioxidants. The main triacylglycerols were SLL + PLO, SOL + POO, OOLn + PLL, OOO, and SOO. This paper examined the phenolic fraction of Pistacia atlantica seed oil. Moreover, caffeic acid followed by cinnamic acid, pinoresinol, vanillin, p-Coumaric acid, ferulic acid, and o-Coumaric acid was also determined. This paper presents the first investigation of chlorophyll's and carotene's composition in Pistacia atlantica seed oil. Furthermore, pheophytin a was the major component, followed by luteoxanthin, neoxanthin, violaxanthin, lutein, lutein isomers, chlorophyll a, chlorophyll a′, and pheophytin a′ were also determined.

  9. Yield and chemical composition of fractions from fermented shrimp biowaste.

    Science.gov (United States)

    Narayan, Bhaskar; Velappan, Suresh Puthanveetil; Zituji, Sakhare Patiram; Manjabhatta, Sachindra Nakkerike; Gowda, Lalitha Ramakrishna

    2010-01-01

    Chemical composition of chitinous residue and fermentation liquor fractions, obtained from fermented shrimp biowaste, was evaluated in order to explore their potential for further utilization. Lyophilization of the liquor fraction obtained after fermentation resulted in a powder rich in both protein (30%) and carotenoids (217.18 +/- 2.89 microg/g). The yield of chitinous residue was 44% (w/w) whereas the yield of lyophilized powder was >25% (w/v). About 69% of total carotenoids were recovered by fermentation. Fermentation resulted in the removal of both protein as well as ash content from the shrimp biowaste, as indicated by approximately 92% deproteination and >76% demineralization, respectively. Post fermentation, the residue had a chitin content of >90%. The lyophilized liquor fraction had all the essential amino acids (except threonine) in quantities comparable to Food & Agriculture Organization/World Health Organization reference protein. The composition of fermentation liquor is indicative of its potential for application as an amino acid supplement in aquaculture feed formulations.

  10. Chemical Composition and Antioxidant Capacity of Three Plum Cultivars

    Directory of Open Access Journals (Sweden)

    Sandra Voća

    2009-12-01

    Full Text Available The aim of this study was to determine the chemical composition and antioxidants capacity of three plum cultivars, namely ‘Top’, ‘Elena’ and ‘Bistrica’. Fruits were harvested and following parameters were determined: dry matter, total acids (TA, total soluble solids (TSS, pH, vitamin C, total phenols, nonflavonoids and antioxidant capacity. Differences between cultivars for most of the chemical parameters were observed. The cultivar ‘Bistrica’ showed higher values of dry matter, TSS, vitamin C and pH value, while ‘Top’ had higher total acids value and lowest TSS, dry matter, vitamin C and pH. Total phenolics content varied from 157.70 mg in ‘Elena’ to 344.10 mg in ‘Bistrica’, expressed as gallic acid equivalents (GAE, on fresh weight basis. ‘Top’ contains the highest amount of non-flavonoids among cultivars studied. Therefore, ‘Bistrica’ and ‘Top’ show the highest antioxidant capacity, as well. There were significant differences between total phenolics and non-flavonoids content between ‘Elena’ and other two cultivars, while antioxidant capacity showed no significant difference (p ≤ 0.05. Total antioxidant capacity of fruits ranged from 3.10 mmol/kg in ‘Elena’ to 3.17 mmol/kg in ‘Top’ and ‘Bistrica’.

  11. SIMS chemical and isotopic analysis of impact features from LDEF experiments AO187-1 and AO187-2

    Science.gov (United States)

    Stadermann, Frank J.; Amari, Sachiko; Foote, John; Swan, Pat; Walker, Robert M.; Zinner, Ernst

    1995-01-01

    Previous secondary ion mass spectrometry (SIMS) studies of extended impact features from LDEF capture cell experiment AO187-2 showed that it is possible to distinguish natural and man-made particle impacts based on the chemical composition of projectile residues. The same measurement technique has now been applied to specially prepared gold target impacts from experiment AO187-1 in order to identify the origins of projectiles that left deposits too thin to be analyzed by conventional energy-dispersive x-ray (EDX) spectroscopy. The results indicate that SIMS may be the method of choice for the analysis of impact deposits on a variety of sample surfaces. SIMS was also used to determine the isotopic compositions of impact residues from several natural projectiles. Within the precision of the measurements all analyzed residues show isotopically normal compositions.

  12. Chemical Composition Measurements of LAWA44 Glass Samples

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-11-15

    The U.S. Department of Energy (DOE) Office of River Protection (ORP) has requested that the Savannah River National Laboratory (SRNL) provide expert evaluation and experimental work in support of the River Protection Project vitrification technology development. DOE is building the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is temporarily stored in 177 underground tanks. The low-activity waste (LAW) fraction will be partitioned from the high-level waste (HLW). Both the LAW and HLW will then be vitrified into borosilicate glass using Joule-heated ceramic melters. Efforts are being made to increase the loading of Hanford tank wastes in the glass while conforming to processing requirements and product quality regulations. DOE-ORP has requested that SRNL support the advancement of glass formulations and process control strategies in key technical areas, as defined in the Task Technical and Quality Assurance Plan (TTQAP). One of these areas is enhancing waste glass composition/property models and broadening the compositional regions over which those models are applicable. In this report, SRNL provides chemical analysis results for several samples of a simulated LAW glass, designated LAWA44, provided by Pacific Northwest National Laboratory (PNNL) as part of an ongoing development task. The objective of the PNNL task is to determine the durability of this glass using EPA Method 1313, which will include test participants at Vanderbilt University and the University of Sheffield. A report on the compositions of similar glasses (referred to as the EPA-series glasses) was issued in March 2016.

  13. A New Mathematical Formulation of the Governing Equations for the Chemical Compositional Simulation

    CERN Document Server

    Bekbauov, Bakhbergen E; Berdyshev, Abdumauvlen

    2015-01-01

    It is the purpose of this work to develop new approach for chemical compositional reservoir simulation, which may be regarded as a sequential method. The development process can be roughly divided into the following two stages: (1) development of a new mathematical formulation for the sequential chemical compositional reservoir simulation, (2) implementation of a sequential solution approach for chemical compositional reservoir simulation based on the formulation described in this paper. This paper addresses the first stage of the development process by presenting a new mathematical formulation of the chemical compositional reservoir flow equations for the sequential simulation. The newly developed mathematical formulation is extended from the model formulation used in existing chemical compositional simulators. During the model development process, it was discovered that the currently used chemical compositional model estimates the adsorption effect on the transport of a component reasonably well but it viol...

  14. Concept of REACH and impact on evaluation of chemicals.

    Science.gov (United States)

    Foth, H; Hayes, Aw

    2008-01-01

    Industrial chemicals have been in use for many decades and new products are regularly invented and introduced to the market. Also for decades, many different chemical laws have been introduced to regulate safe handling of chemicals in different use patterns. The patchwork of current regulation in the European Union is to be replaced by the new regulation on industrial chemical control, REACH. REACH stands for registration, evaluation, and authorization of chemicals. REACH entered force on June 1, 2007. REACH aims to overcome limitations in testing requirements of former regulation on industrial chemicals to enhance competitiveness and innovation with regard to manufacture safer substances and to promote the development of alternative testing methods. A main task of REACH is to address data gaps regarding the properties and uses of industrial chemicals. Producers, importers, and downstream users will have to compile and communicate standard information for all chemicals. Information sets to be prepared include safety data sheets (SDS), chemical safety reports (CSR), and chemical safety assessments (CSA). These are designed to guarantee adequate handling in the production chain, in transport and in use and to prevent the substances from being released to and distributed within the environment. Another important aim is to identify the most harmful chemicals and to set incentives to substitute them with safer alternatives. On one hand, REACH will have substantial impact on the basic understanding of the evaluation of chemicals. However, the toxicological sciences can also substantially influence the workability of REACH that supports the transformation of data to the information required to understand and manage acceptable and non acceptable risks in the use of industrial chemicals. The REACH regulation has been laid down in the main document and 17 Annexes of more than 849 pages. Even bigger technical guidance documents will follow and will inform about the rules for

  15. Chemical composition of olive oils of the cultivar Colombaia

    Directory of Open Access Journals (Sweden)

    Zunin, P.

    2005-12-01

    Full Text Available The chemical composition of monovarietal olive oils from the cultivar Colombaia was studied. Free acidity, peroxide value and UV absorbance attested to the good quality of the analyzed oils. Their fatty acid composition appeared to be quite different from the typical fatty acid profile of olive oils from Liguria but met the limits reported in the EC Regulations for olive oils. On the contrary, the amounts of Δ7-stigmastenol were often higher than the 0.5 % limit set by EC Regulations and total ß-sitosterol was below the minimum 93 % limit. The composition of polar compounds and of the volatile fraction was representative of the peculiar organoleptic character of these oils. Thus, the anomalous sterol composition of the monovarietal oils from the cultivar Colombaia calls for blending with other oils. Moreover, the use of these oils for the production of PDO oils “Riviera Ligure” must also be carefully controlled because it changes their nutritional and sensorial featuresEn este trabajo se ha estudiado la composición química de aceites de oliva mono-varietales de la variedad Colombaia. La acidez libre, el índice de peróxidos y la absorción UV confirmaron la buena calidad de los aceites analizados. Su composición en ácidos grasos resultó bastante diferente del perfil típico de ácidos grasos de los aceites de oliva virgen de la región de Liguria, pero se mantuvo dentro de los límites establecidos por los Reglamentos EC para aceites de oliva. Por otro lado, las cantidades de Δ7-estigmastenol resultaron normalmente superiores al 0.5 % del límite fijado por los Reglamentos EC y el ß-sitosterol total fue inferior al 93 % del límite mínimo. La composición en compuestos polares y de la fracción volátil confirmó las características organolépticas peculiares de estos aceites. Por tanto, la composición esterólica anómala de los aceites mono-varietales de la variedad Colombaia hace necesaria una mezcla con otros

  16. Chemical composition of the circumstellar disk around AB Aurigae

    Science.gov (United States)

    Pacheco-Vázquez, S.; Fuente, A.; Agúndez, M.; Pinte, C.; Alonso-Albi, T.; Neri, R.; Cernicharo, J.; Goicoechea, J. R.; Berné, O.; Wiesenfeld, L.; Bachiller, R.; Lefloch, B.

    2015-06-01

    Aims: Our goal is to determine the molecular composition of the circumstellar disk around AB Aurigae (hereafter, AB Aur). AB Aur is a prototypical Herbig Ae star and the understanding of its disk chemistry is paramount for understanding the chemical evolution of the gas in warm disks. Methods: We used the IRAM 30-m telescope to perform a sensitive search for molecular lines in AB Aur as part of the IRAM Large program ASAI (a chemical survey of Sun-like star-forming regions). These data were complemented with interferometric observations of the HCO+ 1→0 and C17O 1→0 lines using the IRAM Plateau de Bure Interferometer (PdBI). Single-dish and interferometric data were used to constrain chemical models. Results: Throughout the survey, several lines of CO and its isotopologues, HCO+, H2CO, HCN, CN, and CS, were detected. In addition, we detected the SO 54→33 and 56→45 lines, confirming the previously tentative detection. Compared to other T Tauri and Herbig Ae disks, AB Aur presents low HCN 3→2/HCO+ 3→2 and CN 2→1/HCN 3→2 line intensity ratios, similar to other transition disks. AB Aur is the only protoplanetary disk detected in SO thus far, and its detection is consistent with interpretation of this disk being younger than those associated with T Tauri stars. Conclusions: We modeled the line profiles using a chemical model and a radiative transfer 3D code. Our model assumes a flared disk in hydrostatic equilibrium. The best agreement with observations was obtained for a disk with a mass of 0.01 M⊙, Rin = 110 AU, Rout = 550 AU, a surface density radial index of 1.5, and an inclination of 27°. The intensities and line profiles were reproduced within a factor of ˜2 for most lines. This agreement is reasonable considering the simplicity of our model that neglects any structure within the disk. However, the HCN 3→2 and CN 2→1 line intensities were predicted to be more intense by a factor of >10. We discuss several scenarios to explain this

  17. The Relationship of Culture Media Composition and Chemical Composition on Spirulina sp for Metal Ion Adsorbent

    Directory of Open Access Journals (Sweden)

    Hilda Zulkifli

    2016-12-01

    Full Text Available The analysis relationship of Spirulina sp medium with chemical composition has been conducted. Chemical analysis was performed using X-Ray Fluorescence analysis. Furthermore, potention of Spirulina sp as adsorbent of metal ions was analyzed using FTIR spectroscopy. The results showed that metals such as Zn, Fe, Mn, Ca, Cu, and Mo were mainly metals in Spirulina sp. These metals were not correlated with cultivated medium of Spirulina sp. Analysis of potention Spirulina sp as metal ions adsorbent showed that Spirulina sp has functional groups –C=O and –OH as ligand. Intercation of metal ions Cu(II and Cr(III with Spirulina sp indicated that metal ions bond to –C=O functional group.

  18. Managing the impacts of endocrine disrupting chemicals in wastewater-impacted streams

    Science.gov (United States)

    Journey, Celeste A.; Bradley, Paul M.; Kolpin, Dana W.; Bradley, Paul M.

    2013-01-01

    A revolution in analytical instrumentation circa 1920 greatly improved the ability to characterize chemical substances [1]. This analytical foundation resulted in an unprecedented explosion in the design and production of synthetic chemicals during and post-World War II. What is now often referred to as the 2nd Chemical Revolution has provided substantial societal benefits; with modern chemical design and manufacturing supporting dramatic advances in medicine, increased food production, and expanding gross domestic products at the national and global scales as well as improved health, longevity, and lifestyle convenience at the individual scale [1, 2]. Presently, the chemical industry is the largest manufacturing sector in the United States (U.S.) and the second largest in Europe and Japan, representing approximately 5% of the Gross Domestic Product (GDP) in each of these countries [2]. At the turn of the 21st century, the chemical industry was estimated to be worth more than $1.6 trillion and to employ over 10 million people, globally [2]. During the first half of the 20th century, the chemical sector expanded rapidly, the chemical industry enjoyed a generally positive status in society, and chemicals were widely appreciated as fundamental to individual and societal quality of life. Starting in the 1960s, however, the environmental costs associated with the chemical industry increasingly became the focus, due in part to the impact of books like “Silent Spring” [3] and “Our Stolen Future” [4] and to a number of highly publicized environmental disasters. Galvanizing chemical industry disasters included the 1976 dioxin leak north of Milan, Italy, the Love Canal evacuations in Niagara, New York beginning in 1978, and the Union Carbide leak in Bhopal, India in 1984 [2]. Understanding the environmental impact of synthetic compounds is essential to any informed assessment of net societal benefit, for the simple reason that any chemical substance that is in

  19. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    CERN Document Server

    Côté, Benoit; Ritter, Christian; Herwig, Falk; Venn, Kim A

    2016-01-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of Type Ia supernovae and the strength of gal...

  20. Thermodynamic Branch in the Chemical System Response to External Impact

    CERN Document Server

    Zilbergleyt, B

    2012-01-01

    The paper gives an account of a detailed investigation of the thermodynamic branch as a path of the chemical system deviation from its isolated thermodynamic equilibrium under an external impact. For a combination of direct and reverse reactions in the same chemical system, full thermodynamic branch is presented by an S-shaped curve, whose ends asymptotically achieve appropriate initial states, which, in turn, are logistic ends of the opposite reactions. The slope tangents of the steepest parts of the curves, the areas of the maximum rate of the shift growth vs. the external thermodynamic force, occurred to be directly proportional to the force and, simultaneously, linearly proportional to the thermodynamic equivalent of chemical reaction, which is the ratio between the amount in moles of any reaction participant, transformed in an isolated system, along the reaction way from its initial state to thermodynamic equilibrium, to its stoichiometric coefficient. The found linearity is valid for arbitrary combinati...

  1. On the origin and composition of Theia: Constraints from new models of the Giant Impact

    CERN Document Server

    Meier, Matthias M M; Wieler, Rainer

    2014-01-01

    Knowing the isotopic composition of Theia, the proto-planet which collided with the Earth in the Giant Impact that formed the Moon, could provide interesting insights on the state of homogenization of the inner solar system at the late stages of terrestrial planet formation. We use the known isotopic and modeled chemical compositions of the bulk silicate mantles of Earth and Moon and combine them with different Giant Impact models, to calculate the possible ranges of isotopic composition of Theia in O, Si, Ti, Cr, Zr and W in each model. We compare these ranges to the isotopic composition of carbonaceous chondrites, Mars, and other solar system materials. In the absence of post-impact isotopic re-equilibration, the recently proposed high angular momentum models of the Giant Impact ("impact-fission", Cuk & Stewart, 2012; and "merger", Canup, 2012) allow - by a narrow margin - for a Theia similar to CI-chondrites, and Mars. The "hit-and-run" model (Reufer et al., 2012) allows for a Theia similar to enstatit...

  2. Wear and impact resistance of HVOF sprayedceramic matrix composites coating

    Science.gov (United States)

    Prawara, B.; Martides, E.; Priyono, B.; Ardy, H.; Rikardo, N.

    2016-02-01

    Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr3C2) base and ceramic-metal NiAl-Al2O3 with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr3C2 and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.

  3. Chemical reactions induced by high-velocity molecular impacts: challenges for closed-source mass spectrometry

    Science.gov (United States)

    Austin, Daniel

    2016-07-01

    Analysis of upper atmosphere composition using closed-source neutral mass spectrometers (e.g., Cassini INMS, MAVEN NGIMS) is subject to error due to chemical reactions caused by the high-velocity impacts of neutral molecules on the source surfaces. In addition to species traditionally considered "surface reactive" (e.g., O, N) it is likely that many or all impacting molecules are vibrationally excited to the point that chemical changes can occur. Dissociation, fragmentation, formation of radicals and ions, and other reactions likely obscure analysis of the native atmospheric composition, particularly of organic compounds. Existing techniques are not capable of recreating the relevant impact chemistry in the lab. We report on the development of a new capability allowing reactions of high-velocity neutrals impacting surfaces to be characterized directly. Molecules introduced into a vacuum chamber are impacted at several km/s by the surface of a high-speed rotor. These molecules subsequently impact multiple times on other surfaces within the vacuum chamber until they are thermalized, after which they are cryogenically collected and analyzed. Reaction pathways and thermodynamics for volatile compounds are then determined. We will present current results on this project, including data from low- and mid-range velocity experiments. This type of information is critical to clarify prior flight results and plan for future missions. Finally, we present a new type of inlet intended to significantly reduce fragmentation for impact velocities typical of a fly-by mission. Theoretical analysis indicates that this new inlet may reduce fragmentation by more than an order of magnitude for any encounter velocity.

  4. Chemical composition and antioxidant activities of Broussonetia papyrifera fruits.

    Directory of Open Access Journals (Sweden)

    Jie Sun

    Full Text Available 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.

  5. Chemical Composition of Urban Street Sediments and Its Sources

    Institute of Scientific and Technical Information of China (English)

    Cen Kuang; Hou Min; Thomas Neumann; Stefan Norra; Doris Stüben

    2004-01-01

    The distribution and the concentrations of various chemical elements in street sediments were investigated along a rural-urban boundary in Beijing, China. The statistical factor analysis of the data concerned identifies two anthropogenic sources responsible for the contamination of Beijing air. The first source is a steel factory in the western part of Beijing. From this source, Mn, Fe and Ti were emitted into the atmosphere through chimneys and by wind from coal heaps used as the primary energy source for the factory. The second source is a combination of traffic, domestic heating and some small factories in the center of Beijing urban area discharging Cu, Pb, Zn and Sn. Grain-size analyses show that most of the metals in the road dust have higher concentrations in the small grain-size fraction <0.125 mm, which is the severest case because these small particles with larger specific surface area and high heavy metal contents fly up easily and float in the air for a long time. Besides the anthropogenic contamination, such elements as Y, Zr, Nb, Ce and Rb are derived mainly both from natural soils and from the deserts. This is supported by mineral-phase analysis, which shows a clear imprint of materials in road dusts coming from the west China deserts. Our results clearly show that the chemical compositions of the urban road dusts can be used to identify distinctive sources responsible for the contamination mentioned above. The study shows that the chemistry of road dusts is an important monitor to assess the contamination in the urban environment.

  6. Fatigue Performance of Composite Laminates After Low-velocity Impact

    Directory of Open Access Journals (Sweden)

    LIANG Xiao-lin

    2016-12-01

    Full Text Available Compression-compression fatigue tests were carried out on T300/5405 composite laminates after low-velocity impact, compression performance of the laminates with different impact damages was studied together with its fatigue life and damage propagation under different stress levels, then the effects of impact energy, stress level and damage propagation on fatigue life of laminates were discussed. The results indicate that impact damage can greatly reduce the residual strength of laminates; under low fatigue load levels, the higher impact energy is, the shorter the fatigue life of laminates with impact damage will be; damage propagation undergoes two stages during the fatigue test, namely the steady propagation and the rapid propagation, accounting for 80% and 20% of the overall fatigue life, respectively; damage propagation rate decreases with the reduction of stress level.

  7. Soursop (Annona muricata) vinegar production and its chemical compositions

    Science.gov (United States)

    Ho, Chin Wai; Lazim, Azwan Mat; Fazry, Shazrul; Zaki, Umi Kalsum Hj Hussain; Lim, Seng Joe

    2016-11-01

    Vinegar is a liquid product that undergoes double fermentations, which are alcoholic and acetous fermentation. Sugar source was converted to ethanol in alcoholic fermentation, meanwhile ethanol was oxidised to acetic acid during acetous fermentation. Soursop (Annona muricata) was the starting material in this study, as it is easily available in Malaysia. Its highly aromatic, juicy and distinctive flavours enables the production of high quality vinegar. The objective of this research is to produce good quality soursop vinegar as an innovative method to preserve and utilise the soursop fruit in Malaysia and to determine its chemical compositions. It was found that the sugar content reduces over time, and it is inversely proportional to the ethanol concentration, due to the production of ethanol from sugar. Acetic acid was also found to increase with increasing fermentation time. pH showed no significant difference (p>0.05) in the reduction of sugar and the production of ethanol. However, significantly higher (p 0.05) in Vitamin C contents in all soursop vinegar samples produced using different treatments.

  8. Tea tree oil: contact allergy and chemical composition.

    Science.gov (United States)

    de Groot, Anton C; Schmidt, Erich

    2016-09-01

    In this article, contact allergy to, and the chemical composition of, tea tree oil (TTO) are reviewed. This essential oil is a popular remedy for many skin diseases, and may be used as neat oil or be present in cosmetics, topical pharmaceuticals and household products. Of all essential oils, TTO has caused most (published) allergic reactions since the first cases were reported in 1991. In routine testing, prevalences of positive patch test reactions have ranged from 0.1% to 3.5%. Nearly 100 allergic patients have been described in case reports and case series. The major constituents of commercial TTO are terpinen-4-ol, γ-terpinene, 1,8-cineole, α-terpinene, α-terpineol, p-cymene, and α-pinene. Fresh TTO is a weak to moderate sensitizer, but oxidation increases its allergenic potency. The major sensitizers appear to be ascaridole, terpinolene, α-terpinene, 1,2,4-trihydroxymenthane, α-phellandrene, and limonene. The clinical picture of allergic contact dermatitis caused by TTO depends on the products used. Most reactions are caused by the application of pure oil; cosmetics are the culprits in a minority of cases. Patch testing may be performed with 5% oxidized TTO. Co-reactivity to turpentine oil is frequent, and there is an overrepresentation of reactions to fragrance mix I, Myroxylon pereirae, colophonium, and other essential oils.

  9. Anisotropy vs chemical composition at ultra-high energies

    CERN Document Server

    Lemoine, Martin

    2009-01-01

    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 E_{thr}, one should record an even stronger (possibly much stronger) anisotropy at energies >E_{thr}/Z due to the proton component that is expected to be associated with the sources of the heavy nuclei. This conclusion remains robust with respect to the parameters characterizing the sources and it does not depend at all on the modelling of astrophysical magnetic fields. As a concrete example, we apply this test to the most recent data of the Pierre Auger Observatory. Assuming that the anisotropy reported above 55EeV is not a statistical accident, and that no significant anisotropy has been observed at energies 10^{45}Z^{-2}erg/s. Using this bound in conjunction with the above conclusions, we argue that the current PAO data...

  10. Study of Aerosol Chemical Composition Based on Aerosol Optical Properties

    Science.gov (United States)

    Berry, Austin; Aryal, Rudra

    2015-03-01

    We investigated the variation of aerosol absorption optical properties obtained from the CIMEL Sun-Photometer measurements over three years (2012-2014) at three AERONET sites GSFC; MD Science_Center and Tudor Hill, Bermuda. These sites were chosen based on the availability of data and locations that can receive different types of aerosols from land and ocean. These absorption properties, mainly the aerosol absorption angstrom exponent, were analyzed to examine the corresponding aerosol chemical composition. We observed that the retrieved absorption angstrom exponents over the two sites, GSFC and MD Science Center, are near 1 (the theoretical value for black carbon) and with low single scattering albedo values during summer seasons indicating presence of black carbon. Strong variability of aerosol absorption properties were observed over Tudor Hill and will be analyzed based on the air mass embedded from ocean side and land side. We will also present the seasonal variability of these properties based on long-range air mass sources at these three sites. Brent Holben, NASA GSFC, AERONET, Jon Rodriguez.

  11. Pereskia aculeata Muller (Cactaceae Leaves: Chemical Composition and Biological Activities

    Directory of Open Access Journals (Sweden)

    Lucèia Fàtima Souza

    2016-09-01

    Full Text Available The aims of this work were to study the chemical composition of the essential oil from the leaves of Pereskia aculeata and to evaluate some biological activities of three leaf extracts. The phenolic content, antioxidant activity, and in vitro antimicrobial and antifungal activities were determined. The methanol extract showed antioxidant activity (EC50 7.09 mg/mL and high polyphenols content (15.04 ± 0.31 mg gallic acid equivalents (GAE/g. The petroleum ether extract exhibited potent antibacterial activity against Escherichia coli, whereas the chloroform extract showed inhibitory activity against Bacillus cereus and Staphylococcus aureus. The petroleum ether and methanol extracts were more effective in inhibiting the growth of Aspergillus versicolor. The possible cytotoxicity of extracts on neuroblastoma SH-SY5Y cancer cell line and the influence on adenylate cyclase (ADCY expression was also studied. P. aculeata chloroform extract showed antiproliferative activity with an IC50 value of 262.83 µg/mL. Treatments of SH-SY5Y neuroblastoma cells with 100 µg/mL of methanol extract significantly reduced ADCY1 expression.

  12. Pereskia aculeata Muller (Cactaceae) Leaves: Chemical Composition and Biological Activities.

    Science.gov (United States)

    Souza, Lucèia Fàtima; Caputo, Lucia; Inchausti De Barros, Ingrid Bergman; Fratianni, Florinda; Nazzaro, Filomena; De Feo, Vincenzo

    2016-09-03

    The aims of this work were to study the chemical composition of the essential oil from the leaves of Pereskia aculeata and to evaluate some biological activities of three leaf extracts. The phenolic content, antioxidant activity, and in vitro antimicrobial and antifungal activities were determined. The methanol extract showed antioxidant activity (EC50 7.09 mg/mL) and high polyphenols content (15.04 ± 0.31 mg gallic acid equivalents (GAE)/g). The petroleum ether extract exhibited potent antibacterial activity against Escherichia coli, whereas the chloroform extract showed inhibitory activity against Bacillus cereus and Staphylococcus aureus. The petroleum ether and methanol extracts were more effective in inhibiting the growth of Aspergillus versicolor. The possible cytotoxicity of extracts on neuroblastoma SH-SY5Y cancer cell line and the influence on adenylate cyclase (ADCY) expression was also studied. P. aculeata chloroform extract showed antiproliferative activity with an IC50 value of 262.83 µg/mL. Treatments of SH-SY5Y neuroblastoma cells with 100 µg/mL of methanol extract significantly reduced ADCY1 expression.

  13. Reducing chemical vapour infiltration time for ceramic matrix composites.

    Science.gov (United States)

    Timms, L. A.; Westby, W.; Prentice, C.; Jaglin, D.; Shatwell, R. A.; Binner, J. G. P.

    2001-02-01

    Conventional routes to producing ceramic matrix composites (CMCs) require the use of high temperatures to sinter the individual ceramic particles of the matrix together. Sintering temperatures are typically much higher than the upper temperature limits of the fibres. This paper details preliminary work carried out on producing a CMC via chemical vapour infiltration (CVI), a process that involves lower processing temperatures, thus avoiding fibre degradation. The CVI process has been modified and supplemented in an attempt to reduce the CVI process time and to lower the cost of this typically expensive process. To this end microwave-enhanced CVI (MECVI) has been chosen, along with two alternative pre-infiltration steps: electrophoretic infiltration and vacuum bagging. The system under investigation is based on silicon carbide fibres within a silicon carbide matrix (SiCf/SiC). The results demonstrate that both approaches result in an enhanced initial density and a consequent significant reduction in the time required for the MECVI processing step. Dual energy X-ray absorptiometry was used as a non-destructive, density evaluation technique. Initial results indicate that the presence of the SiC powder in the pre-form changes the deposition profile during the MECVI process.

  14. Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

    Directory of Open Access Journals (Sweden)

    Kanniah Rajasekaran

    2013-04-01

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

  15. Chemical compositions of two different Thymus species essential oils

    Directory of Open Access Journals (Sweden)

    Samira Jaberi

    2015-06-01

    Full Text Available Thymus is one of the most important members of Lamiaceae family. Aerial parts of the plant have been widely used in medicine. It has been reported that most of these effects are related to phenolic compounds especially thymol and carvacrol in Thymus essential oil. In this study, aerial parts of Thymus daenensis and Thymus lancifolius were collected from Kohgiluyeh and Boyer-Ahmad, Iran. Essential oils of aerial parts of these plants were gained by the hydrodistillation method and the chemical compositions were analyzed by gas chromatography/ Mass spectrometry (GC/MS. The major components of the essential oil of T. daenensis were thymol (39.91%, carvacrol (29.93%, linalool (5.55%, caryophyllene (3.5% and geraniol (3.09%, whereas the major components of the essential oil of T. lancifolius were: carvacrol (25.55%, thymol (20.79%, linalool (16.8%, α-terpineol (6.34%, borneol (4.00%, caryophyllene (3.98%, p-cymene (3.38% and cis-linalool oxide (3.21%. Linalool was reported as another major component in T. lancifolius

  16. Chemical composition and quality of sweet sorghum and maize silages

    Directory of Open Access Journals (Sweden)

    Zbigniew PODKÓWKA

    2011-10-01

    Full Text Available Sweet sorghum (Sorghum saccharatum silage, maize (Zea mays silage, and sorghum and maize (1:1 silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88% in sorghum silage and the highest (37.45% in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre and acid detergent fibre were the highest in sorghum silage and the lowest in maize silage. The silages were dominated by lactic acid, with trace amounts of butyric acid. Maize silage was higher lactic acid and higher total acids than others. All silages were of very good quality according to Flieg-Zimmer scale. Silage pH ranged from 4.20 to 4.31. Sorghum silage was characterized by higher aerobic stability (81h compared to the other silages from maize (74h and sorghum and maize 1:1 (69h.

  17. Chemical composition of biomass from tall perennial tropical grasses

    Energy Technology Data Exchange (ETDEWEB)

    Prine, G.M. [Univ. of Florida, Gainesville, FL (United States); Stricker, J.A. [Polk County Extension Office, Bartow, FL (United States); Anderson, D.L. [Everglades Research and Education Center, Belle Glade, FL (United States)] [and others

    1995-11-01

    The tall perennial tropical grasses, elephantgrass (Pennisetum purpureum Schum.), sugarcane and energycane (Saccharum sp.) and erianthus (Erianthus arundenaceum (Retz) Jesw.) have given very high oven dry biomass yields in Florida and the warm Lower South USA. No good complete analyses of the chemical composition of these grasses for planning potential energy use was available. We sampled treatments of several tall grass demonstrations and experiments containing high-biomass yielding genotypes of the above tall grass crops at several locations in Florida over the two growing seasons, 1992 and 1993. These samples were analyzed for crude protein, NDF, ADF, cellulose, hemicellulose, lignin, and IVDMD or IVOMD. The analysis for the above constituents are reported, along with biomass yields where available, for the tall grass accessions in the various demonstrations and experiments. Particular attention is given to values obtained from the high-yielding tall grasses grown on phosphatic clays in Polk County, FL, the area targeted by a NREL grant to help commercialize bioenergy use from these crops.

  18. Chemical composition and antigenotoxic properties of Lippia alba essential oils

    Directory of Open Access Journals (Sweden)

    Molkary Andrea López

    2011-01-01

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

  19. Brazilian kefir: structure, microbial communities and chemical composition

    Directory of Open Access Journals (Sweden)

    Karina Teixeira Magalhães

    2011-06-01

    Full Text Available 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.

  20. Chemical composition and antibacterial activity of Gongronema latifolium

    Institute of Scientific and Technical Information of China (English)

    ELEYINMI Afolabi F.

    2007-01-01

    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.

  1. Microbial population, chemical composition and silage fermentation of cassava residues.

    Science.gov (United States)

    Napasirth, Viengsakoun; Napasirth, Pattaya; Sulinthone, Tue; Phommachanh, Kham; Cai, Yimin

    2015-09-01

    In order to effectively use the cassava (Manihot esculenta Crantz) residues, including cassava leaves, peel and pulp for livestock diets, the chemical and microbiological composition, silage preparation and the effects of lactic acid bacteria (LAB) inoculants on silage fermentation of cassava residues were studied. These residues contained 10(4) to 10(5) LAB and yeasts, 10(3) to 10(4) coliform bacteria and 10(4) aerobic bacteria in colony forming units (cfu) on a fresh matter (FM) basis. The molds were consistently at or below the detectable level (10(2) cfu of FM) in three kinds of cassava residues. Dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) content of cassava residues were 17.50-30.95%, 1.30-16.41% and 25.40-52.90% on a DM basis, respectively. The silage treatments were designed as control silage without additive (CO) or with LAB inoculants Chikuso-1 (CH, Lactobacillus plantarum) and Snow Lacto (SN, Lactobacillus rhamnosus) at a rate of 5 mg/kg of FM basis. All silages were well preserved with a low pH (below 4.0) value and when cassava residues silage treated with inoculants CH and SN improved fermentation quality with a lower pH, butyric acid and higher lactic acid than control silage.

  2. Chemical compositions of precipitation and scavenging of particles in Beijing

    Institute of Scientific and Technical Information of China (English)

    HU Min; ZHANG Jing; WU Zhijun

    2005-01-01

    Totally 23 precipitation samples were collected in Beijing from May to November in 2003. In order to investigate the chemical composition of precipitation samples, pH, conductivity, concentrations of water-soluble ions and organic acids were analyzed. The average pH of precipitations is 6.18, belonging to the neutral range; the average conductivity is 52.23 (S/cm, which indicates that precipitations in Beijing are obviously polluted; are the most abundant anions with the average concentrations of 521 and 174 μeq·L-1, respectively; the average equivalent ratio is 3.1, which decreases by about 15% compared with the result of 1994; and Ca2+ are the most abundant cations with the average concentrations of 376 and 397 μeq·L-1, respectively; formic acid, acetic acid and oxalic acid are the main organic acids with the average concentrations of 4.62, 4.60 and 1.17 μeq·L-1, respectively, accounting for 2% of the overall anions. Obvious differences between concentrations before and after precipitation are also observed by SJAC (Steam Jet Aerosol Collector), which shows the removal of particles from the atmosphere by precipitation.

  3. Chemical composition and antigenotoxic properties of Lippia alba essential oils.

    Science.gov (United States)

    López, Molkary Andrea; Stashenko, Elena E; Fuentes, Jorge Luis

    2011-07-01

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

  4. INFLUENCE OF IMPACT MODIFIER AND COUPLING AGENT ON IMPACT STRENGTH OF WOOD FLOUR / RECYCLED PLASTIC COMPOSITES

    OpenAIRE

    Saman GHAHRI; Saeed KAZEMI NAJAFI; Mohebby, Behbood

    2014-01-01

    In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP) composites was investigated. The PP (virgin and recycled polypropylene) and wood flour (WF) were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA) and ethylene/propylene/diene terpolymer (EPDM)), to produce wood flour-PP composites specimen. The results showed t...

  5. Seminar for hydrocarbon detection with composite geophysical/geo-chemical techniques

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    “Seminar for hydrocarbon detection with composite geophy sical/geo-chemical techniques”,jointly organized by China petroleum Exploration & Production Company and Exploration Geophysical Committee of CGS and supported by the Composite Geophysical/geo-chemical Departement of Oriental Geophysical Company and China Exploration&Development Research Instiute,

  6. Chemical composition analysis of simulated waste glass T10-G-16A

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-01

    In this report, SRNL provides chemical composition analyses of a simulated LAW glass designated T10-G-16A.The measured chemical composition data are reported and compared with the targeted values for each component. No issues were identified in reviewing the analytical data.

  7. Boron carbide: Consistency of components, lattice parameters, fine structure and chemical composition makes the complex structure reasonable

    Science.gov (United States)

    Werheit, Helmut

    2016-10-01

    The complex, highly distorted structure of boron carbide is composed of B12 and B11C icosahedra and CBC, CBB and B□B linear elements, whose concentration depends on the chemical composition each. These concentrations are shown to be consistent with lattice parameters, fine structure data and chemical composition. The respective impacts on lattice parameters are estimated and discussed. Considering the contributions of the different structural components to the energy of the overall structure makes the structure and its variation within the homogeneity range reasonable; in particular that of B4.3C representing the carbon-rich limit of the homogeneity range. Replacing in B4.3C virtually the B□B components by CBC yields the hypothetical moderately distorted B4.0C (structure formula (B11C)CBC). The reduction of lattice parameters related is compatible with recently reported uncommonly prepared single crystals, whose compositions deviate from B4.3C.

  8. Impact test on natural fiber reinforced polymer composite materials

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2013-06-01

    Full Text Available In this research, natural fibers like Sisal (Agave sisalana, Banana (Musa sepientum & Roselle (Hibiscus sabdariffa , Sisal and banana (hybrid , Roselle and banana (hybrid and Roselle and sisal (hybrid are fabricated with bio epoxy resin using molding method. In this work, impact strength of Sisal and banana (hybrid, Roselle and banana (hybridand Roselle and sisal (hybrid composite at dry and wet conditions were studied. Impact test were conducted izod impact testing machine. In this work micro structure of the specimens are scanned by the Scanning Electron Microscope.

  9. Tensile & impact behaviour of natural fibre-reinforced composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B.C. [Victoria Univ. of Technology, Footscray (Australia). Dept. of Mechanical Engineering

    1993-12-31

    Short abaca fiber reinforced composite materials are fabricated and investigated for short term performance. Abaca plants which grow in abundance in Asia contain fibers that are inexpensive but underutilized. This study attempts to utilize the abaca fibers for composite material structure as a possible alternative to timber products in building applications. The composite material is fabricated using the hand lay-up method under varying fiber length and fiber volume fraction. The fibers are impregnated with a mixture of resins which cures at room temperature. A fabricating facility is designed to accommodate fabrication of lamina. Tensile and impact properties are determined in relation to the length and volume fraction of the fiber. For a given fiber length, the tensile and impact strength increase as the volume fraction increases up to a limiting value. And for a given fiber volume fraction, the tensile strength increases but the impact strength decreases as the fiber length increases. This behavior of abaca fiber-reinforced composite lamina will help in optimizing the design parameter in random composite panels.

  10. Low and high velocity impact response of thick hybrid composites

    Science.gov (United States)

    Hiel, Clement; Ishai, Ori

    1993-01-01

    The effects of low and high velocity impact on thick hybrid composites (THC's) were experimentally compared. Test Beams consisted of CFRP skins which were bonded onto an interleaved syntactic foam core and cured at 177 C (350 F). The impactor tip for both cases was a 16 mm (0.625 inch) steel hemisphere. In spite of the order of magnitude difference in velocity ranges and impactor weights, similar relationships between impact energy, damage size, and residual strength were found. The dependence of the skin compressive strength on damage size agree well with analytical open hole models for composite laminates and may enable the prediction of ultimate performance for the damaged composite, based on visual inspection.

  11. Structural Health Monitoring for Impact Damage in Composite Structures.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

    2014-08-01

    Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

  12. Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

    Science.gov (United States)

    Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

    2009-01-01

    The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

  13. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2007-04-01

    Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

  14. Chemical composition and leishmanicidal activity of Pulicaria gnaphalodes essential oil

    Directory of Open Access Journals (Sweden)

    G. Asghari

    2014-10-01

    Full Text Available Background and objectives: Several natural compounds have been identified for the treatment ofleishmaniasis. Due to a few safe drugs and the side effects caused by available chemotherapy, some new drugs for treatment of leishmaniasis are requested.  The genus Pulicaria (Asteraceae is represented in the flora of Iran by five species. Phytochemical studies on Pulicaria species have revealed some flavonoids and terpenoids with leishmanicidal activity. In the present investigation chemical composition and leishmanicidal activity of Pulicaria gnaphalodes essential oil have been studied. Methods: The essential oil of the aerial parts of the plant was obtained by Clevenger apparatus and was analyzed by GC/MS. Antileishmanil activity was assessed against promastigoes of Leishmania major. Results:The major components from P. gnaphalodes essential oil have been reported to be geraniol, 1,8-cineole, chrysanthenone, α-pinene, chrystanthenone, α-terpineol and filifolone. The alcohol monoterpenes with contribution of 25.04% constituted the major portion of the essential oil, while hydrocarbon monoterpenes and hydrocarbon sesquiterpenes with contribution of 7.08% and 2.38%, respectively occupied the next rates.In the present experiment the essential oil of P. gnaphalodes progressively inhibited Leishmania major growth in concentrations ranging from 0.125 to 50 µL/mL (parasite culture in 24 h. The essential oil at 50 µL/mL eliminated the promastigotes at the beginning of treatment. It showed antileishmanial activity in concentration of 1.06 µL/mL and destroyed all parasits in 24 h.  Conclusion: Pulicaria gnaphalodes antileishmanial activity, could suggest the species and constituents as possible lead structures for antileishmanial drug discovery.

  15. Chemical composition and antioxidant activity of berry fruits

    Directory of Open Access Journals (Sweden)

    Stajčić Slađana M.

    2012-01-01

    Full Text Available The main chemical composition, contents of total phenolic (TPh, total flavonoid (TF, and total monomeric anthocyianin (TMA, as well as the antioxidant activity of two raspberry cultivars (Meeker and Willamette, two blackberry cultivars (Čačanska bestrna and Thornfree and wild bilberry were studied. The raspberry cultivars had the highest total solids among fruits investigated. Bilberry fruits had the highest sugar-to-acid ratio. Blackberry fruits were richer in crude fibers (cellulose in comparison to raspberry and bilberry fruits. The content of pectic substances was highest in the bilberry. Also, bilberry had a highest content of TPh (808.12 mg GAE/100 g FW, TF (716.31 mg RE/100 g FW and TMA (447.83 mg CGE/100 g FW. The antioxidant activity was evaluated spectrophotometrically, using 2,2-diphenyl-1-picrylhydrazyl (DPPH radical scavenging activity assay. The DPPH free radical scavenging activity, expressed as the EC50 value (in mg of fresh weight of berry fruit per ml of the reaction mixture, of bilberry (0.3157 ± 0.0145 mg/ml was the highest. These results also showed that the antioxidant value of 100 g FW bilberry, raspberry - Willamette, raspberry - Meeker, blackberry - Čačanska bestrna and blackberry - Thornfree is equivalent to 576.50 mg, 282.74 mg, 191.58 mg, 222.28 mg and 272.01 mg of vitamin C, respectively. There was a significant positive correlation between the antioxidant activities and content of total phenolics (RTPh 2=0.9627, flavonoids (RTF 2=0.9598 and anthocyanins (RTMA 2=0.9496 in berry fruits. [Projekat Ministarstva nauke Republike Srbije, br. TR 31044

  16. Brazilian Propolis: Correlation between Chemical Composition and Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Kelly Salomão

    2008-01-01

    Full Text Available 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.

  17. Chemical composition of buckwheat plant parts and selected buckwheat products

    Directory of Open Access Journals (Sweden)

    Petra Vojtíšková

    2014-11-01

    Full Text Available Chemical composition plant parts (roots, stalks, leaves, blossoms of common buckwheat (Fagopyrum esculentum Moench and selected products made from its seeds (peels, whole seed, wholemeal flour, broken seeds, crunchy products Natural and Cocoa, flour, and pasta was determined. Samples were dried and ground to a fine powder. All analyses were performed according to the Commission Regulation no. 152/2009, while rutin concentration was determined by the modified HPLC method. The lowest content of moisture was found in roots (4.3% and in peels (almost 8% and the highest moisture (nearly 11% was discovered in seeds. The lowest amount of crude protein (3.5% was found in peels, the highest crude protein amount (>13% in both flours and leaves (23%. The starch content (>50% in dry matter differs from one sample to another. Only in peels the content of starch was about 3.5%. From all examined samples, the lowest content of fat was found in crunchy products Cocoa, 1.7%. The lowest amount of histidine was determined in all studied samples, except peels, the highest content of glutamic acid was determined in almost all samples, except peels. Whole-meal flour is very rich source of Ca and Fe. The content of these elements was 1172 mg.kg-1 and 45.9 mg.kg-1, respectively. On the other hand, the highest content of Pb (>1 mg.kg-1 was found in broken seeds. The greatest concentration of rutin was determined in blossoms and leaves (83.6 and 69.9 mg.g-1, respectively. On the other hand, the lowest concentrations of rutin were found in buckwheat products (generally less then 1 mg.g-1, i.e. in wholemeal flour, 702 μg.kg-1, the lowest almost 10 μg.kg-1 in pasta.

  18. RESEARCH REGARDING THE CHEMICAL COMPOSITION AT VINEGAR TYPES

    OpenAIRE

    Liviu Giurgiulescu; Olimpia Mihaela Hoban

    2009-01-01

    In this article are presented some physico-chemical applied vinegar, to see some chemical properties of vinegar suchas total acidity, volatile and fixed, by colorimetric determination of iron content in the vinegar, the extract andresidue determination dry.

  19. Computational modeling and impact analysis of textile composite structures

    Science.gov (United States)

    Hur, Hae-Kyu

    This study is devoted to the development of an integrated numerical modeling enabling one to investigate the static and the dynamic behaviors and failures of 2-D textile composite as well as 3-D orthogonal woven composite structures weakened by cracks and subjected to static-, impact- and ballistic-type loads. As more complicated modeling about textile composite structures is introduced, some of homogenization schemes, geometrical modeling and crack propagations become more difficult problems to solve. To overcome these problems, this study presents effective mesh-generation schemes, homogenization modeling based on a repeating unit cell and sinusoidal functions, and also a cohesive element to study micro-crack shapes. This proposed research has two: (1) studying behavior of textile composites under static loads, (2) studying dynamic responses of these textile composite structures subjected to the transient/ballistic loading. In the first part, efficient homogenization schemes are suggested to show the influence of textile architectures on mechanical characteristics considering the micro modeling of repeating unit cell. Furthermore, the structures of multi-layered or multi-phase composites combined with different laminar such as a sub-laminate, are considered to find the mechanical characteristics. A simple progressive failure mechanism for the textile composites is also presented. In the second part, this study focuses on three main phenomena to solve the dynamic problems: micro-crack shapes, textile architectures and textile effective moduli. To obtain a good solutions of the dynamic problems, this research attempts to use four approaches: (I) determination of governing equations via a three-level hierarchy: micro-mechanical unit cell analysis, layer-wise analysis accounting for transverse strains and stresses, and structural analysis based on anisotropic plate layers, (II) development of an efficient computational approach enabling one to perform transient

  20. Future changes of the atmospheric composition and the impact of climate change

    Energy Technology Data Exchange (ETDEWEB)

    Grewe, V.; Dameris, M.; Hein, R.; Sausen, R. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Steil, B. [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany). Abt. Chemie der Atmosphaere

    1999-05-01

    The development of the future atmospheric chemical composition, with respect of NO{sub y} and O{sub 3} is investigated by means of the off-line coupled dynamic-chemical general circulation model ECHAM3/CHEM. Two time slice experiments have been performed for the years 1992 and 2015, which include changes in sea surface temperatures, greenhouse gas concentrations, emissions of CFCs, NO{sub x} and other species, i.e., the 2015 simulation accounts for changes in chemically relevant emissions and for a climate change and its impact on air chemistry. The 2015 simulation clearly shows a global increase in ozone except for large areas of the lower stratosphere, where no significant changes or even decreases in the ozone concentration are found. For a better understanding of the importance of (A) emissions like NO{sub x} and CFCs, (B) future changes of air temperature and water vapour concentration, and (C) other dynamic parameters, like precipitation and changes in the circulation, i.e. wind speed, diabatic circulation, stratosphere-troposphere-exchange, the simulation of the future atmosphere has been performed stepwise. This method requires a climate-chemistry model without interactive coupling of chemical species. Model results show that the direct effect of emissions (A) plays a major role for the composition of the future atmosphere, but they also clearly show that climate change has a significant impact and strongly reduces the NO{sub y} and ozone concentration in the lower stratosphere. (orig.)

  1. Biogas crops grown in energy crop rotations: Linking chemical composition and methane production characteristics.

    Science.gov (United States)

    Herrmann, Christiane; Idler, Christine; Heiermann, Monika

    2016-04-01

    Methane production characteristics and chemical composition of 405 silages from 43 different crop species were examined using uniform laboratory methods, with the aim to characterise a wide range of crop feedstocks from energy crop rotations and to identify main parameters that influence biomass quality for biogas production. Methane formation was analysed from chopped and over 90 days ensiled crop biomass in batch anaerobic digestion tests without further pre-treatment. Lignin content of crop biomass was found to be the most significant explanatory variable for specific methane yields while the methane content and methane production rates were mainly affected by the content of nitrogen-free extracts and neutral detergent fibre, respectively. The accumulation of butyric acid and alcohols during the ensiling process had significant impact on specific methane yields and methane contents of crop silages. It is proposed that products of silage fermentation should be considered when evaluating crop silages for biogas production.

  2. Impact Resistance of Uncoated SiC/SiC Composites

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Choi, Sung R.; Cosgriff, Laura M.; Fox, Dennis S.; Lee, Kang N.

    2008-01-01

    Two-dimensional woven SiC/SiC composites fabricated by melt infiltration method were impact tested at room temperature and at 1316 C in air using 1.59-mm diameter steel-ball projectiles at velocities ranging from 115 to 400 m/s. The extent of substrate damage with increasing projectile velocity was imaged and analyzed using optical and scanning electron microscopy, and non-destructive evaluation (NDE) methods such as pulsed thermography, and computed tomography. The impacted specimens were tensile tested at room temperature to determine their residual mechanical properties. Results indicate that at 115 m/s projectile velocity, the composite showed no noticeable surface or internal damage and retained its as-fabricated mechanical properties. As the projectile velocity increased above this value, the internal damage increased and mechanical properties degraded: At velocities >300 m/s, the projectile penetrated through the composite, but the composite retained approx.50% of the ultimate tensile strength of the as-fabricated composite and exhibited non-brittle failure. Predominant internal damages are delamination of fiber plies, fiber fracture and matrix shearing.

  3. Impact of the nonvolatile wine matrix composition on the in vivo aroma release from wines.

    Science.gov (United States)

    Muñoz-González, Carolina; Martín-Álvarez, Pedro J; Moreno-Arribas, M Victoria; Pozo-Bayón, M Ángeles

    2014-01-08

    The impact of the nonvolatile wine matrix composition on the retronasal aroma release of four volatile compounds added to different types of wines has been evaluated. For this purpose, a tailor-made retronasal aroma trapping device (RATD) was used to entrap the exhaled breath of six panelists previously trained in a specific consumption procedure. Five wines of different composition (white wine, sparkling white wine, young red wine, aged red wine, and a sweet wine) were evaluated. Prior to the evaluation, with the exception of the sweet wine, the wines were adjusted to the same ethanol content and aromatized with a mixture of four target volatile compounds. Aroma release data were submitted to multivariate statistical analysis in order to relate wine chemical composition and aroma release during wine drinking. Results showed interindividual differences and a clustering of panelists among lower and higher aroma releasers, which was in agreement to the differences in their breathing capacity. A significant influence of the matrix composition in the low aroma releasers group during wine consumption was observed. The consumption of red wines provoked a significantly higher aroma release than the consumption of white and sweet wines. From the chemical composition determined in the wine samples (pH, total acidity, total polyphenols, neutral polysaccharides, residual sugar, and nitrogenous compounds), the amount of total polyphenols was better correlated with the observed effect.

  4. Mathematical modeling of chemical composition modification and etching of polymers under the atomic oxygen influence

    Science.gov (United States)

    Chirskaia, Natalia; Novikov, Lev; Voronina, Ekaterina

    2016-07-01

    Atomic oxygen (AO) of the upper atmosphere is one of the most important space factors that can cause degradation of spacecraft surface. In our previous mathematical model the Monte Carlo method and the "large particles" approximation were used for simulating processes of polymer etching under the influence of AO [1]. The interaction of enlarged AO particles with the polymer was described in terms of probabilities of reactions such as etching of polymer and specular and diffuse scattering of the AO particles on polymer. The effects of atomic oxygen on protected polymers and microfiller containing composites were simulated. The simulation results were in quite good agreement with the results of laboratory experiments on magnetoplasmadynamic accelerator of the oxygen plasma of SINP MSU [2]. In this paper we present a new model that describes the reactions of AO interactions with polymeric materials in more detail. Reactions of formation and further emission of chemical compounds such as CO, CO _{2}, H _{2}O, etc. cause the modification of the chemical composition of the polymer and change the probabilities of its consequent interaction with the AO. The simulation results are compared with the results of previous simulation and with the results of laboratory experiments. The reasons for the differences between the results of natural experiments on spacecraft, laboratory experiments and simulations are discussed. N. Chirskaya, M. Samokhina, Computer modeling of polymer structures degradation under the atomic oxygen exposure, WDS'12 Proceedings of Contributed Papers: Part III - Physics, Matfyzpress Prague, 2012, pp. 30-35. E. Voronina, L. Novikov, V. Chernik, N. Chirskaya, K. Vernigorov, G. Bondarenko, and A. Gaidar, Mathematical and experimental simulation of impact of atomic oxygen of the earth's upper atmosphere on nanostructures and polymer composites, Inorganic Materials: Applied Research, 2012, vol. 3, no. 2, pp. 95-101.

  5. Chemical composition and its origin in spring rainwater over Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    WANG Xuemei; YANG Longyuan; QIN Boqiang; JI Lingling

    2006-01-01

    Chemical compositions of rainwater collected in three stations in Taihu Lake in Jiangsu Province, China between March and May 2003 were analyzed through numerical simulations and field observation data. In terms of average ion deposition rate in spring at the air/water interface, of all anions,that of so2-4 was the largest followed by NO-3, whereas among all cations, Ca2+ concentration and the rate was the largest, and then NH4+ was the next. The correlation of ion concentration indicated that the catchment of the lake has been artificially polluted considerably. Using backward trajectory analysis, the raining water in the stations in Taihu Lake was classified. In spring, marine-originated rain is the main contribution to this area, counting for 92.7% of the total precipitation, in which SO2-4, NO-3 and NH+4 contributed 89.2%, 88.1%, and 88.3% respectively to the total spring-rain chemicals, whereas land-originated rains contributed in a small amount. However, the ion concentration in the land-originated rain was higher and acidic, causing considerable harm to local ecosystem. The analysis of backward trajectory analysis shows that three types of air masses influenced the chemical composition of the lake water, namely, air mass from NE direction, air mass from SW direct ion, and local air mass. Although the local air masses often produced small rainfall amount, but the nature of high ion concentration and high acidity impacted the local ecosystem remarkably. The ion concentration and rainfall from long-distance boreal air mass are clearly greater than those in austral air.

  6. Mineral and inorganic chemical composition of the Pernik coal, Bulgaria

    Energy Technology Data Exchange (ETDEWEB)

    Yossifova, Mariana G. [Geological Institute, Acad. G. Bonchev Str., Bl.24, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2007-11-22

    The mineral and inorganic chemical composition of five types of samples from the Pernik subbituminous coals and their products generated from the Pernik preparation plant were studied. They include feed coal, low-grade coal, high-grade coal, coal slime, and host rock. The mineral matter of the coals contains 44 species that belong mainly to silicates, carbonates, sulphates, sulphides, and oxides/hydroxides, and to a lesser extent, chlorides, biogenic minerals, and organic minerals. The detrital minerals are quartz, kaolinite, micas, feldspars, magnetite, cristobalite, spessartine, and amphibole. The authigenic minerals include various sulphides, silicates, oxihydroxides, sulphates, and carbonates. Several stages and substages of formation were identified during the syngenetic and epigenetic mineral precipitations of these coals. The authigenic minerals show the greatest diversity of mineral species as the epigenetic mineralization (mostly sulphides, carbonates, and sulphates) dominates qualitatively and quantitatively. The epigenetic mineralization was a result of complex processes occurring mostly during the late development of the Pernik basin. These processes indicate intensive tectonic, hydrothermal and volcanic activities accompanied by a change from fresh to marine sedimentation environment. Thermally altered organic matter due to some of the above processes was also identified in the basin. Most of the trace elements in the Pernik coals (Mo, Be, S, Zr, Y, Cl, Ba, Sc, Ga, Ag, V, P, Br, Ni, Co, Pb, Ca, and Ti) show an affinity to OM and phases intimately associated with OM. Some of the trace elements (Sr, Ti, Mn, Ba, Pb, Cu, Zn, Co, Cr, Ni, As, Ag, Yb, Sn, Ga, Ge, etc.) are impurities in authigenic and accessory minerals, while other trace elements (La, Ba, Cu, Ce, Sb, Bi, Zn, Pb, Cd, Nd, etc.) occur as discrete phases. Elements such as Sc, Be, Y, Ba, V, Zr, S, Mo, Ti, and Ga exceed Clarke concentrations in all of the coal types studied. It was also found that

  7. Impact Parameter Dependent Parton Distributions for a Composite Relativistic System

    CERN Document Server

    Chakraborty, D

    2004-01-01

    We investigate the impact parameter dependent parton distributions for a relativistic composite system in light-front framework. We take an effective two-body spin-1/2 state, namely an electron dressed with a photon in QED. We express the impact parameter dependent parton distributions in terms of overlaps of light-cone wave functions. We obtain the scale dependence of both fermion and gauge boson distributions and show the distortion of the pdfs in the transverse space for transverse polarization of the state at one loop level.

  8. Chemical composition and photochemical reactivity of exhaust from aircraft turbine engines

    Directory of Open Access Journals (Sweden)

    T. F. Lyon

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

  9. Fluid Structure Interaction Effects on Composites Under Low Velocity Impact

    Science.gov (United States)

    2012-06-01

    Interaction, FSI, low velocity impact, carbon fiber reinforced polymers, CFRP, carbon nanotubes, CNT, vacuum assisted resin transfer molding, VARTM . 16...Ethyl Ketone Peroxide MWCNT Multi-Walled Carbon Nanotube VARTM Vacuum-Assisted Resin Transfer Molding xiv THIS PAGE INTENTIONALLY LEFT BLANK...samples used in this research is known as vacuum assisted resin transfer molding ( VARTM ). VARTM is a very common method used in low pressure composite

  10. Impact Parameter Dependent Parton Distributions for a Relativistic Composite System

    CERN Document Server

    Chakraborty, D

    2004-01-01

    We investigate the impact parameter dependent parton distributions for a relativistic composite system in light-front framework. We express them in terms of overlaps of light-cone wave functions for a self consistent two-body spin-1/2 state, namely an electron dressed with a photon in QED. The pdfs are distorted in the transverse space for transverse polarization of the state at one loop level.

  11. Chemical composition of nanomodified composite binder with nano- and microsized barium silicate

    Directory of Open Access Journals (Sweden)

    KOROLEV Evgenij Valerjevich

    2014-08-01

    Full Text Available There are several possibilities to improve cement-based binders. In particular, many properties of cement stone can be enhanced by means of micro- and nanoscale modification. In a number of previous works we had shown that application of barium hydrosilicates leads to such improvement. The present article is devoted to the investigation of the chemical composition of the cement stone which is modified by means of addition of barium hydrosilicates. The modification was performed on different scales: micro- and nanoscale; the results of simultaneous multi-scale modification are also presented. The examination was carried out with help of different modern research techniques – FT IR spectroscopy, differential thermal analysis and X-ray phase analysis. Identification of the new phases and comparative quantitative assessment of their content are performed. It is found that the use of nano- and micro-sized barium hydrosilicates as additives leads to reduction of portlandite by 27...28%; by means of multi-scale modification it is possible to reduce the content of portlandite much more (by 83.3%. Due to addition of nano- and micro-sized barium-based modifiers both the amount of calcium hydrosilicates in reaction products is enlarged, and structure of the mentioned hydrosilicates is changed (the formation of a fine-grained structure of hydration products takes place. Micro-sized barium hydrosilicates are chemically active additives and promote the formation of an additional quantity of calcium hydrosilicates of type CSH (I. The use of nanoscale barium hydrosilicates promotes the formation of CSH (I and CSH (II calcium hydrosilicates, and also both riversidite and xonotlite. As a result of simultaneous application of nano- and micro-sized barium hydrosilicates the content of CSH (II increases. This can be confirmed by means of differential thermal and X-ray analysis. The amount of CSH (I, riversidite and various tobermorites is also increases. It is

  12. Composition of Plasma Formed from Hypervelocity Dust Impacts

    Science.gov (United States)

    Lee, N.; Close, S.; Rymer, A. M.; Mocker, A.

    2012-12-01

    Dust impacts can occur on all solar system bodies but are especially prevalent in the case of the Saturnian moons that are near or within the dust torus produced by Enceladus's plumes. Depending on the mass and charge on these plume particles, they will be influenced by both gravitational and electrodynamic forces, resulting in a range of possible impact speeds on the moons. The plasma formed upon impact can have very different characteristics depending on impact speed and on the electric field due to surface charging at the impact point. Through recent tests conducted at the Max Planck Institute for Nuclear Physics using a Van de Graaff dust accelerator, iron dust particles were electrostatically accelerated to speeds of 3-65 km/s and impacted on a variety of target materials including metallic and glassy surfaces. The target surfaces were connected to a biasing supply to represent surface charging effects. Because of the high specific kinetic energy of the dust particles, upon impact they vaporize along with part of the target surface and a fraction of this material is ionized forming a dense plasma. The impacts produced both positive and negative ions. We made measurements of the net current imparted by this expanding plasma at a distance of several centimeters from the impact point. By setting the bias of the target, we impose an electric field on the charge population, allowing a measurement of plasma composition through time of flight analysis. The figure shows representative measurements of the net current measured by a retarding potential analyzer (RPA) from separate 18 and 19 km/s impacts of 7 fg particles on a glassy surface that was negatively and positively biased, respectively. This target was an optical solar reflector donated by J. Likar of Lockheed Martin for these experiments. These results show that ions of both positive and negative charge can be formed through the mechanism of dust impacts, and has implications on the surface plasma environment

  13. Level and Chemical Composition of Cryoglobulins in Schizophrenia

    Science.gov (United States)

    Khoyetsyan, Aren; Boyajyan, Anna; Melkumova, Maya

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

  14. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    Science.gov (United States)

    Côté, Benoit; O’Shea, Brian W.; Ritter, Christian; Herwig, Falk; Venn, Kim A.

    2017-02-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. This provides a consistent framework for comparing the best-fit solutions generated by our different models. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. This result supports the similar conclusions originally claimed by Romano & Starkenburg for Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of SNe Ia and the strength of galactic outflows, are substantially different and in fact mutually exclusive from one model to another. For the purpose of understanding how a galaxy evolves, we conclude that only reproducing the evolution of a limited number of elements is insufficient and can lead to misleading conclusions. More elements or additional constraints such as the Galaxy’s star-formation efficiency and the gas fraction are needed in order to break the degeneracy between the different modeling assumptions. Our results show that the successes and failures of chemical evolution models are predominantly driven by the input stellar yields, rather than by the complexity of the Galaxy model itself. Simple models such as OMEGA are therefore sufficient to test and validate stellar yields. OMEGA

  15. Effects of chemical composition on the corrosion of dental alloys

    OpenAIRE

    GALO, Rodrigo; RIBEIRO, Ricardo Faria; RODRIGUES, Renata Cristina Silveira; Rocha, Luís Augusto; Mattos,Maria da Glória Chiarello de

    2012-01-01

    The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the g...

  16. Variation in size, morphology and chemical composition of polymetallic nodules from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Karisiddaiah, S.M.; Parthiban, G.

    Chemical composition of 613 polymetallic nodules from 150 stations in the Central Indian Ocean Basin (CIOB) are determined and variations in Mn, Fe, Cu, Ni, Co, Zn and moisture content are studied with respect to their size and surface texture...

  17. Chemical composition and antibacterial activity of essential oils against human pathogenic bacteria

    NARCIS (Netherlands)

    Sokovic, M.; Marin, P.D.; Brkic, D.; Griensven, van L.J.L.D.

    2008-01-01

    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. Anti

  18. Chemically and Thermally Stable High Energy Density Silicone Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal energy storage systems with 300 ? 1000 kJ/kg energy density through either phase changes or chemical heat absorption are sought by NASA. This proposed effort...

  19. Chemical composition and antibacterial activity of essential oils from the Tunisian Allium nigrum L.

    OpenAIRE

    Rouis-Soussi, Lamia Sakka; Ayeb-Zakhama, El Asma; Mahjoub, Aouni; Flamini, Guido; Jannet, Hichem Ben; Harzallah-Skhiri, Fethia

    2014-01-01

    The chemical composition of the essential oils of different Allium nigrum L. organs and the antibacterial activity were evaluated. The study is particularly interesting because hitherto there are no reports on the antibacterial screening of this species with specific chemical composition. Therefore, essential oils from different organs (flowers, stems, leaves and bulbs) obtained separately by hydrodistillation were analyzed using gas chromatography–mass spectrometry (GC–MS). The antibacterial...

  20. Changes to the chemical composition of soot from heterogeneous oxidation reactions.

    Science.gov (United States)

    Browne, Eleanor C; Franklin, Jonathan P; Canagaratna, Manjula R; Massoli, Paola; Kirchstetter, Thomas W; Worsnop, Douglas R; Wilson, Kevin R; Kroll, Jesse H

    2015-02-19

    The atmospheric aging of soot particles, in which various atmospheric processes alter the particles' chemical and physical properties, is poorly understood and consequently is not well-represented in models. In this work, soot aging via heterogeneous oxidation by OH and ozone is investigated using an aerosol flow reactor coupled to a new high-resolution aerosol mass spectrometric technique that utilizes infrared vaporization and single-photon vacuum ultraviolet ionization. This analytical technique simultaneously measures the elemental and organic carbon components of soot, allowing for the composition of both fractions to be monitored. At oxidant exposures relevant to the particles' atmospheric lifetimes (the equivalent of several days of oxidation), the elemental carbon portion of the soot, which makes up the majority of the particle mass, undergoes no discernible changes in mass or composition. In contrast, the organic carbon (which in the case of methane flame soot is dominated by aliphatic species) is highly reactive, undergoing first the addition of oxygen-containing functional groups and ultimately the loss of organic carbon mass from fragmentation reactions that form volatile products. These changes occur on time scales comparable to those of other nonoxidative aging processes such as condensation, suggesting that further research into the combined effects of heterogeneous and condensational aging is needed to improve our ability to accurately predict the climate and health impacts of soot particles.

  1. Influence of Impact Modifier and Coupling Agent on Impact Strength of Wood Flour/Recycled Plastic Composites

    Directory of Open Access Journals (Sweden)

    Saman GHAHRI

    2014-03-01

    Full Text Available In this research, the improvement of impact strength of wood flour/recycled polypropylene (PP composites was investigated. The PP (virgin and recycled polypropylene and wood flour (WF were compounded at 50% by weight wood flour loading in a counter-rotating twin-screw extruder in the presence MAPP and two types of impact modifiers (ethylene vinyl acetate (EVA and ethylene/propylene/diene terpolymer (EPDM, to produce wood flour-PP composites specimen. The results showed that the composites containing recycled PP exhibited significantly lower impact strength values than those of containing virgin PP. The addition of MAPP, EVA and EPDM in the specimens increased their impact strength. In the presence of MAPP, higher increase in impact strength of the recycled PP/WF composites was observed due to impact modifiers. Both impact modifiers increased the impact strength of the PP/WF composites but the addition of EVA gave the greatest improvements in impact strength. Although the addition of impact modifiers and MAPP increased the impact strength of composites containing recycled PP, such values were still significantly lower than those of containing virgin PP (not modified with MAPP or impact modifier. The use of impact modifiers decreased the flexural properties of the recycled PP/WF composites.

  2. Milk production and chemical composition of milk of Ukrainian mountain Carpathian sheep in pasture period

    OpenAIRE

    CHOKAN T.

    2011-01-01

    The comparative analysis of the milk chemical composition depending on milk productivity of Ukrainian Mountain Carpathian sheep during the pasture period were studied. It was found changes of milk composition (increasing of protein content, fat, dry matter and nutritive value) with a decrease of milk yield in the end period of lactation.

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

    NARCIS (Netherlands)

    Westerhout, J.; Borodin, D.; Al, R.S.; Brezinsek, S.; Hoen, Mhjt; 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.; Cardozo, N. J. L.; Rapp, J.; van Rooij, G. J.

    2009-01-01

    We have studied the chemical erosion of different carbon composites in Pilot-PSI at ITER-relevant hydrogen plasma fluxes (similar to 10(24) m(-2) s(-1)) and low electron temperatures (T-e similar to 1 eV). Optical emission spectroscopy on the CH A-X band was used to characterize the chemical sputter

  4. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  5. High Energy Wide Area Blunt Impact on Composite Aircraft Structures

    Science.gov (United States)

    DeFrancisci, Gabriela K.

    The largest source of damage to commercial aircraft is caused by accidental contact with ground service equipment (GSE). The cylindrical bumper typically found on GSE distributes the impact load over a large contact area, possibly spanning multiple internal structural elements (frame bays) of a stiffened-skin fuselage. This type of impact can lead to damage that is widespread and difficult to detect visually. To address this problem, monolithic composite panels of various size and complexity have been modeled and tested quasi-statically and dynamically. The experimental observations have established that detectability is dependent on the impact location and immediately-adjacent internal structure of the panel, as well as the impactor geometry and total deformation of the panel. A methodology to model and predict damage caused by wide area blunt impact events was established, which was then applied to more general cases that were not tested in order to better understand the nature of this type of impact event and how it relates to the final damage state and visual detectability.

  6. Recent Advances in the Chemical Composition of Propolis

    Directory of Open Access Journals (Sweden)

    Shuai Huang

    2014-11-01

    Full Text Available Propolis is a honeybee product with broad clinical applications. Current literature describes that propolis is collected from plant resins. From a systematic database search, 241 compounds were identified in propolis for the first time between 2000 and 2012; and they belong to such diverse chemical classes as flavonoids, phenylpropanoids, terpenenes, stilbenes, lignans, coumarins, and their prenylated derivatives, showing a pattern consistent with around 300 previously reported compounds. The chemical characteristics of propolis are linked to the diversity of geographical location, plant sources and bee species.

  7. Pasta added with chickpea flour: chemical composition, In vitro starchdigestibility and predicted glycemic index

    OpenAIRE

    2008-01-01

    Pasta was prepared with of durum wheat flour mixed with chickpea flour at two different levels and its chemical composition, in vitro starch digestibility and predicted glycemic index were assessed. Protein, ash, lipid, and dietary fiber content increased while total starch decreased with the chickpea flour level in the composite pasta, all in accordance to the composition of the legume flour. Potentially available starch decreased and resistant starch (RS) increased by adding chickpea flour ...

  8. Finite-element impact response of debonded composite turbine blades

    Science.gov (United States)

    Dey, Sudip; Karmakar, Amit

    2014-02-01

    This paper investigates on the transient behavior of debonded composite pretwisted rotating shallow conical shells which could be idealized as turbine blades subjected to low velocity normal impact using finite-element method. Lagrange's equation of motion is used to derive the dynamic equilibrium equation and the moderate rotational speeds are considered neglecting the Coriolis effect. An eight-noded isoparametric plate bending element is employed in the finite element formulation incorporating rotary inertia and effects of transverse shear deformation based on Mindlin's theory. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the impact parameters. The time-dependent equations are solved by using Newmark's time integration scheme. Parametric studies are performed to investigate the effects of triggering parameters like angle of twist, rotational speed, laminate configuration and location of debonding considering low velocity normal impact at the center of eight-layered graphite-epoxy composite cantilevered conical shells with bending stiff ([0o2/{±} 30o]s), torsion stiff ([45°/-45°/-45°/45°]s) and cross-ply ([0°/90°/0°/90°]s) laminate configurations.

  9. On the formation and chemical composition of super Earths

    Science.gov (United States)

    Alessi, Matthew; Pudritz, Ralph E.; Cridland, Alex J.

    2017-01-01

    Super Earths are the largest population of exoplanets and are seen to exhibit a rich diversity of compositions as inferred through their mean densities. Here we present a model that combines equilibrium chemistry in evolving discs with core accretion that tracks materials accreted on to planets during their formation. In doing so, we aim to explain why super Earths form so frequently and how they acquire such a diverse range of compositions. A key feature of our model is disc inhomogeneities, or planet traps, that act as barriers to rapid type-I migration. The traps we include are the dead zone, which can be caused by either cosmic ray or X-ray ionization, the ice line, and the heat transition. We find that in discs with sufficiently long lifetimes (≳4 Myr), all traps produce Jovian planets. In these discs, planet formation in the heat transition and X-ray dead zone produces hot Jupiters, while the ice line and cosmic ray dead zones produce Jupiters at roughly 1 au. Super Earth formation takes place within short-lived discs (≲2 Myr), whereby the discs are photoevaporated while planets are in a slow phase of gas accretion. We find that super Earth compositions range from dry and rocky (30 per cent ice by mass). The traps play a crucial role in our results, as they dictate where in the disc particular planets can accrete from, and what compositions they are able to acquire.

  10. On the Formation and Chemical Composition of Super Earths

    Science.gov (United States)

    Alessi, Matthew; Pudritz, Ralph E.; Cridland, Alex J.

    2016-09-01

    Super Earths are the largest population of exoplanets and are seen to exhibit a rich diversity of compositions as inferred through their mean densities. Here we present a model that combines equilibrium chemistry in evolving disks with core accretion that tracks materials accreted onto planets during their formation. In doing so, we aim to explain why super Earths form so frequently and how they acquire such a diverse range of compositions. A key feature of our model is disk inhomogeneities, or planet traps, that act as barriers to rapid type-I migration. The traps we include are the dead zone, which can be caused by either cosmic ray or X-ray ionization, the ice line, and the heat transition. We find that in disks with sufficiently long lifetimes (≳ 4 Myr), all traps produce Jovian planets. In these disks, planet formation in the heat transition and X-ray dead zone produces hot Jupiters while the ice line and cosmic ray dead zones produce Jupiters at roughly 1 AU. Super Earth formation takes place within short-lived disks (≲ 2 Myr), whereby the disks are photoevaporated while planets are in a slow phase of gas accretion. We find that super Earth compositions range from dry and rocky ( 30 % ice by mass). The traps play a crucial role in our results, as they dictate where in the disk particular planets can accrete from, and what compositions they are able to acquire.

  11. Chemical composition and in vitro dry matter digestibility of lichens

    Directory of Open Access Journals (Sweden)

    Torstein H. Garmo

    1986-06-01

    Full Text Available The chemical composition and in vitro dry matter digestibility of 45 samples of different species of lichen are reported. Mean content (g/100 g dry matter of the main nutrients was: crude protein 4.2, crude fat 3.2, crude fibre 16.6, ash 1.9, Ca 0.15, P 0.09, Mg 0.05, K 0.13, Na 0.035, S 0.07. The content of microminerals (mg/kg dry matter was: Cu 2.5, Mo 0.11, Zn 27.2, Se 0.12, Fe 898, Mn 154. The mean in vitro dry matter digestibility was 35%. However, the in vitro method do underestimate the dry matter digestibility of lichens. Stereocaulon spp. showed higher levels of crude protein, P, S, Cu and Mo than Cetraria spp. and Cladonia spp. Cetraria nivalis showed higher digestibility and contained more NFE, ash, Ca, Mg, but less crude fibre than Cladonia stellaris. Lichens contained less amounts of most nutrients compared with grasses (Fig. 1, exept for crude fat, NFE, Se and Fe.Kjemisk innhald og in vitro fordøyelsesgrad av lav.Abstract in Norwegian / Samandrag: Kjemisk innhald og in vitro fordøyelsesgrad av tørrstoffet er bestemt i 45 prøver av beitelav frå to stader i Sør-Noreg. Middel innhald (g/100g tørrstoff av følgjande næringsstoff var: protein 4.2, feitt 3.2, trevlar 16.6, oske 1.9, kalsium 0.15, fosfor 0.09, magnesium 0.05, kalium 0.13, natrium 0.035, svovel 0.07. Innhaldet (mg/kg tørrstoff av mikronæringsstoffa var: kopar 2.5, molybden 0.11, sink 27.2, selen 0.12, jern 898 og mangan 154. Den midlare fordøyelsesgraden av tørrstoffet i lav-prøvene var 35%, men in vitro fordøyelsesanalyser undervurderer fordøyelsesgraden av lav. Det var ein stor variasjon mellom dei ulike lavartane for dei fleste næringsstoffa og fordøyelsesgraden. Stereocaulon spp. inneheldt meir protein, fosfor, svovel, kopar og molybden enn Cetraria spp. og Cladonia spp. Gulskinn hadde høgare fordøyelsesgrad, og innehaldet av NFE, oske, kalsium og magnesium var høgre enn i kvitkrull, medan trevleinnhaldet var størst i kvitkrull. Lav inneheldt

  12. Optical transmission scanning for damage quantification in impacted GFRP composites

    Science.gov (United States)

    Khomenko, Anton; Karpenko, Oleksii; Koricho, Ermias G.; Haq, Mahmoodul; Cloud, Gary L.; Udpa, Lalita

    2016-04-01

    Glass fiber reinforced polymer (GFRP) composites constitute nearly 90% of the global composites market and are extensively used in aerospace, marine, automotive and construction industries. While their advantages of lightweight and superior mechanical properties are well explored, non-destructive evaluation (NDE) techniques that allow for damage/defect detection and assessment of its extent and severity are not fully developed. Some of the conventional NDE techniques for GFRPs include ultrasonics, X-ray, IR thermography, and a variety of optical techniques. Optical methods, specifically measuring the transmission properties (e.g. ballistic optical imaging) of specimens, provide noninvasive, safe, inexpensive, and compact solutions and are commonly used in biomedical applications. In this work, this technique is adapted for rapid NDE of GFRP composites. In its basic form, the system for optical transmission scanning (OTS) consists of a light source (laser diode), a photo detector and a 2D translation stage. The proposed technique provides high-resolution, rapid and non-contact OT (optical transmittance)-scans, and does not require any coupling. The OTS system was used for inspection of pristine and low-velocity impacted (damaged) GFRP samples. The OT-scans were compared with conventional ultrasonic C-scans and showed excellent agreement but with better resolution. Overall, the work presented lays the groundwork for cost-effective, non-contact, and rapid NDE of GFRP composite structures.

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

    Science.gov (United States)

    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...

  14. Structural Intensity Characterization of Composite Laminates Subjected to Impact Load

    Institute of Scientific and Technical Information of China (English)

    WANG Dong-fang; HE Peng-fei; LIU Zi-shun

    2008-01-01

    Structural intensity (SI) characterization of composite laminates subjected to impact load was dis-cussed. The SI pattern of the laminates which have different fiber orientations and boundary conditions wasanalyzed. The resultant forces and velocities of the laminates were calculated, and the structural intensity wasevaluated. The SI streamlines of carbon fiber reinforced epoxy composite laminates and the steel plates werediscussed. The results show that the SI streamlines of the graphite/epoxy laminates are different from that ofthe steel plates, and the SI streamlines are influenced by the boundaries, the stacking sequence of the compositelaminates. The change of the historical central displacement of the graphite/epoxy laminates is fasten thanthat of the steel plates.

  15. Low velocity impact response and damage evolution in unreinforced resin systems and self-repairing polymer matrix composites

    Science.gov (United States)

    Motuku, Molefi

    The low velocity impact response and damage evolution in unreinforced polymer matrices, conventional polymer matrix composites, and self-repairing polymer matrix composites was investigated. The impact response study of unreinforced matrices and conventional laminates was undertaken because the failure initiation energies, threshold energy levels, failure characteristics and damage evolution in both the matrix material (unreinforced resin plaques) and the composite are intrinsic to proper design of a self-repairing composite. The self-repairing concept was investigated due to its attractive potential to alleviate damage problems in polymer matrix composites. Self-repairing composites, which fall under the category of passive smart polymer composites, have the potential to self repair both micro- and macro-damage resulting from impacts as well as non-impact loading. The self-repairing mechanism is achieved through the incorporation of hollow fibers in addition to the normal solid reinforcing fibers. The hollow fibers store the damage-repairing solution or chemicals that are released into the matrix or damaged zone upon fiber failure to repair and/or arrest damage progression. The room temperature low velocity impact response and damage evolution in DERAKANE 411-350 and 411-C50 vinyl ester unreinforced resin systems was investigated as a function of impact energy level, sample thickness, matrix material and catalyst system. The low velocity impact response of conventional and self-repairing glass reinforced polymer composites was investigated by addressing the fabrication and some of the parameters that influence their response to low velocity impact loading. Specific issues addressed by this study include developing a process to fabricate self-repairing laminates, processing quality; selection of storage material for the repairing solution; release and transportation of repairing solution; the effect of the number, type and spatial distribution of the repairing

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

    Science.gov (United States)

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

    2014-11-01

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

  17. Transient impact responses of laminated composite cylindrical shells

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The generalized ray method(GRM) has been successfully used to study the transient elastic wave transmitting in the beams,planar trusses,space frames and infinite layered media.In this letter,the GRM is extended to investigate the early short time transient responses of laminated composite cylindrical shells under impact load.By using the Laplace transformation and referring to the boundary conditions,the ray groups transmitting in the finite laminated cylindrical shells under the shock load are obtained ...

  18. Rapid Characterization of Woody Biomass Digestibility and Chemical Composition Using Near-infrared Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Shen Hou; Laigeng Li

    2011-01-01

    Rapid determination of the properties of lignocellulosic material is highly desirable for biomass production and utilization. In the present study, measurements of woody biomass digestibility and chemical composition using near-infrared reflectance (NIR) spectroscopy were calibrated. Poplar and eucalyptus materials were recorded in NIR spectrum as well as determined for their chemical compositions of Klason lignin, α-celluiose, holocellulose, lignin syringyl/guaiacyl (S/G) ratio and enzymatic digestibility. Fitting of the NIR information with chemical properties and digestibility by partial least-squares (PLS) regression generated a group of trained NIR models that were able to be used for rapid biomass measurement. Applying the models for woody biomass measurements led to a reliable evaluation of the chemical composition and digestibility, suggesting the feasibility of using NIR spectroscopy in the rapid characterization of biomass properties.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, M.S.

    1993-06-01

    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.

  20. Mechanical behavior of chemically treated Jute/Polymer composites

    Directory of Open Access Journals (Sweden)

    Murali B

    2014-03-01

    Full Text Available Fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural past studies show that only artificial fibers such as glass, carbon etc., have been used in fiber reinforced plastics. Although glass and other synthetic fiber reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. In this connection, an investigation has been carried out to make use of jute , a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight but also relatively very cheap. In the present work, jute composites are developed and their mechanical properties are evaluated. Mechanical properties of jute/polymer and compared with glass fiber/epoxy. These results indicate that jute can be used as a potential reinforcing material for making low load bearing thermoplastic composites.

  1. IMPACTS OF SMALL COLUMN ION EXCHANGE STREAMS ON DWPF GLASS FORMULATION KT07-SERIES GLASS COMPOSITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Edwards, T.

    2011-01-12

    This report is the third in a series of studies of the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. MST from the Salt Waste Processing Facility is also considered in the study. The KT07-series glasses were selected to evaluate any potential impacts of noble metals on their properties and performance. The glasses characterized thus far for the SCIX study have not included noble metals since they are not typically tracked in sludge batch composition projections. However, noble metals can act as nucleation sites in glass melts, leading to enhanced crystallization. This crystallization can potentially influence the properties and performance of the glass, such as chemical durability, viscosity, and liquidus temperature. The noble metals Ag, Pd, Rh, and Ru were added to the KT07-series glasses in concentrations based on recent measurements of Sludge Batch 6, which was considered to contain a high concentration of noble metals. The KT04-series glasses were used as the baseline compositions. After fabrication, the glasses were characterized to determine their homogeneity, chemical composition, durability, and viscosity. Liquidus temperature measurements are also underway but were not complete at the time of this report. The liquidus temperature results for the KT07-series glasses, along with several of the earlier glasses in the SCIX study, will be documented separately. All of the KT07-series glasses, both quenched and slowly cooled, were found to be amorphous by X-ray diffraction. Chemical composition measurements showed that all of the glasses met their targeted compositions. The Product Consistency Test (PCT) results showed that all of the glasses had chemical durabilities that were far better than that of the Environmental Assessment benchmark glass

  2. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; Matlin, W.M.; Stinton, D.P.; Liaw, P.K.

    1996-06-01

    Processing equipment for the infiltration of fiber-reinforced composite tubes is being designed that incorporates improvements over the equipment used to infiltrate disks. A computer-controlled machine-man interface is being developed to allow for total control of all processing variables. Additionally, several improvements are being made to the furnace that will reduce the complexity and cost of the process. These improvements include the incorporation of free standing preforms, cast mandrels, and simpler graphite heating elements.

  3. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

    Processing equipment for the infiltration of fiber-reinforced composite tubes is being designed that incorporates improvements over the equipment used to infiltrate disks. A computer-controlled machine-man interface is being developed to allow for total control of all processing variables. Additionally, several improvements are being made to the furnace that will reduce the complexity and cost of the process. These improvements include the incorporation of free standing preforms, cast mandrels, and simpler graphite heating elements.

  4. Seasonality of new particle formation in Vienna, Austria - Influence of air mass origin and aerosol chemical composition

    Science.gov (United States)

    Wonaschütz, Anna; Demattio, Anselm; Wagner, Robert; Burkart, Julia; Zíková, Naděžda; Vodička, Petr; Ludwig, Wolfgang; Steiner, Gerhard; Schwarz, Jaroslav; Hitzenberger, Regina

    2015-10-01

    The impact of air mass origin and season on aerosol chemical composition and new particle formation and growth events (NPF events) in Vienna, Austria, is investigated using impactor samples from short-term campaigns and two long-term number size distribution datasets. The results suggest that air mass origin is most important for bulk PM concentrations, chemical composition of the coarse fraction (>1.5 μm) and the mass size distribution, and less important for chemical composition of the fine fraction (<1.5 μm). Continental air masses (crustal elements) were distinguished from air masses of marine origin (traces of sea salt). NPF events were most frequent in summer (22% of measurement days), and least frequent in winter (3% of measurement days). They were associated with above-average solar radiation and ozone concentrations, but were largely independent of PM2.5. Air mass origin was a secondary influence on NPF, largely through its association with meteorological conditions. Neither a strong dependence on the PM2.5 loading of the air masses, nor indications of a source area for NPF precursors outside the city were found.

  5. Regulating continent growth and composition by chemical weathering.

    Science.gov (United States)

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

    2008-04-01

    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.

  6. Chemical Composition of the Essential Oil, Total Phenolics, Total Flavonoids and Antioxidant Activity of Methanolic Extracts of Satureja montana L.

    Directory of Open Access Journals (Sweden)

    Avni Hajdari

    2016-05-01

    Full Text Available Aerial parts of Satureja montana L. (Lamiaceae were collected from seven growing wild populations (four populations in Kosovo, two in Albania and one in Montenegro in 2013 with the aim of assessing the natural variation in the chemical composition of the essential oils, total flavonoids, total phenolics and the antioxidant activity of their methanolic extracts. Essential oils were obtained by steam distillation and analysed using GC-FID and GC-MS, whereas total flavonoids, total phenolics and antioxidant activities were determined using spectrophotometric methods. Sixty-one volatile constituents were identified. The main constituents were myrcene, p-cymene, γ-terpinene, linalool, thymol, carvacrol and viridiflorol. Total phenolics ranged from 68.1 to 102.6 mg/g dry mass, the total flavonoid content ranged from 38.3 to 67.0 mg/g dm, and the antioxidant activity according to the DPPH assay ranged from 253.3 to 342.9 mg TE/g dm and according to the FRAP assay ranged from 8.9 to 11.4 mg TE/g dm. Hierarchical cluster analysis and principal component analyses were used to assess the geographical variations in the essential oil composition. Statistical analysis revealed that the analysed populations are grouped into four main clusters that appear to reflect the environmental impact on the chemical composition, which is influenced by differences in habitat composition, altitude and microclimatic conditions.

  7. Chemical Species in the Vapor Phase of Hanford Double-Shell Tanks: Potential Impacts on Waste Tank Corrosion Processes

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Qafoku, Odeta; Arey, Bruce W.; Boomer, Kayle D.

    2010-09-22

    The presence of corrosive and inhibiting chemicals on the tank walls in the vapor space, arising from the waste supernatant, dictate the type and degree of corrosion that occurs there. An understanding of how waste chemicals are transported to the walls and the affect on vapor species from changing supernatant chemistry (e.g., pH, etc.), are basic to the evaluation of risks and impacts of waste changes on vapor space corrosion (VSC). In order to address these issues the expert panel workshop on double-shell tank (DST) vapor space corrosion testing (RPP-RPT-31129) participants made several recommendations on the future data and modeling needs in the area of DST corrosion. In particular, the drying of vapor phase condensates or supernatants can form salt or other deposits at the carbon steel interface resulting in a chemical composition at the near surface substantially different from that observed directly in the condensates or the supernatants. As a result, over the past three years chemical modeling and experimental studies have been performed on DST supernatants and condensates to predict the changes in chemical composition that might occur as condensates or supernatants equilibrate with the vapor space species and dry at the carbon steel surface. The experimental studies included research on both the chemical changes that occurred as the supernatants dried as well as research on how these chemical changes impact the corrosion of tank steels. The chemical modeling and associated experimental studies were performed at the Pacific Northwest National Laboratory (PNNL) and the research on tank steel corrosion at the Savannah River National Laboratory (SRNL). This report presents a summary of the research conducted at PNNL with special emphasis on the most recent studies conducted in FY10. An overall summary of the project results as well as their broader implications for vapor space corrosion of the DST’s is given at the end of this report.

  8. Chemical composition of primary cosmic rays with IceCube

    Science.gov (United States)

    Xu, Chen

    Ground detector arrays have been used to measure high energy cosmic rays for decades to overcome their very low rate. IceCube is a special case with its 3D deployment and unique location---the South Pole. Although all 86 strings and 81 stations of IceCube were completed in 2011, IceCube began to take data in 2006, after the completion of the first 9 strings. In this thesis, experimental data taken in 2009 with 59 strings are used for composition analysis albeit some techniques are illustrated with the 40-string data. Simulation is essential in the composition work. Simulated data must be compared against the experimental data to find the right mix of cosmic ray components. However, because of limited computing resources and complexities of cosmic rays, the simulation in IceCube is well behind the experiment. The lower and upper bounds of primary energy in simulation for events that go through IceTop and the deep arrays of IceCube are 1014 eV and 1017 eV. However, since IceCube has a threshold energy about several hundred TeV, and an upper limit of 10 18 eV, the full energy range cannot be explored in this thesis. The approach taken to the composition problem in this thesis is a 2D Bayesian unfolding. It takes account of the measured IceTop and InIce energy spectrum and outputs the expected primary energy spectrum of different mass components. Studies of the uncertainties in the results are not complete because of limited simulation and understanding of the new detector and South Pole environment.

  9. Characterization of chemical composition of bee pollen in China.

    Science.gov (United States)

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

    2013-01-23

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

  10. Testing chemical composition of highest energy comic rays

    CERN Document Server

    Nosek, D; Noskova, J; Ebr, J

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

    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/.

  12. Simulation of aerosol chemical compositions in the Western Mediterranean Sea

    Science.gov (United States)

    Chrit, Mounir; Kata Sartelet, Karine; Sciare, Jean; Marchand, Nicolas; Pey, Jorge; Sellegri, Karine

    2016-04-01

    This work aims at evaluating the chemical transport model (CTM) Polair3d of the air-quality modelling platform Polyphemus during the ChArMex summer campaigns of 2013, using ground-based measurements performed at ERSA (Cape Corsica, France), and at determining the processes controlling organic aerosol concentrations at ERSA. Simulations are compared to measurements for concentrations of both organic and inorganic species, as well as the ratio of biogenic versus anthropogenic particles, and organic aerosol properties (oxidation state). For inorganics, the concentrations of sulphate, sodium, chloride, ammonium and nitrate are compared to measurements. Non-sea-salt sulphate and ammonium concentrations are well reproduced by the model. However, because of the geographic location of the measurement station at Cape Corsica which undergoes strong wind velocities and sea effects, sea-salt sulphate, sodium, chloride and nitrate concentrations are strongly influenced by the parameterizations used for sea-salt emissions. Different parameterizations are compared and a parameterization is chosen after comparison to sodium measurements. For organics, the concentrations are well modelled when compared to experimental values. Anthropogenic particles are influenced by emission of semi-volatile organic compounds (SVOC). Measurements allow us to refine the estimation of those emissions, which are currently missing in emission inventories. Although concentrations of biogenic particles are well simulated, the organic chemical compounds are not enough oxidised in the model. The observed oxidation state of organics shows that the oligomerisation of pinonaldehyde was over-estimated in Polyphemus. To improve the oxidation property of organics, the formation of extremely low volatile organic compounds from autoxidation of monoterpenes is added to Polyphemus, using recently published data from chamber experiments. These chemical compounds are highly oxygenated and are formed rapidly, as first

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

    Science.gov (United States)

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

    2001-01-01

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

  14. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

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

  15. Fabrication of fiber-reinforced composites by chemical vapor infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Besmann, T.M.; McLaughlin, J.C. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Probst, K.J.; Anderson, T.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Chemical Engineering; Starr, T.L. [Georgia Inst. of Tech., Atlanta, GA (United States). Dept. of Materials Science and Engineering

    1997-12-01

    Silicon carbide-based heat exchanger tubes are of interest to energy production and conversion systems due to their excellent high temperature properties. Fiber-reinforced SiC is of particular importance for these applications since it is substantially tougher than monolithic SiC, and therefore more damage and thermal shock tolerant. This paper reviews a program to develop a scaled-up system for the chemical vapor infiltration of tubular shapes of fiber-reinforced SiC. The efforts include producing a unique furnace design, extensive process and system modeling, and experimental efforts to demonstrate tube fabrication.

  16. Composite reweighting with Imaginary Chemical Potentials in SU(3)

    CERN Document Server

    Crompton, P R

    2002-01-01

    We review the overlap pathology of the Glasgow reweighting method for finite density QCD, and discuss the sampling bias that effects the determination of the ensemble-averaged fugacity polynomial expansion coefficients that form the Grand Canonical Partition function. The expectation of the difference in free energies between canonical partition functions generated with different measures is presented as an indicator of a systematic quark number dependent biasing in the reweighting approach. The advantages of building up an unbiased polynomial expansion for the Grand Canonical Partition function through a series of parallel ensembles generated by reweighting with imaginary chemical potentials are then contrasted with addressing the overlap pathology through a secondary reweighting.

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

    Science.gov (United States)

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

    2011-04-05

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

  18. Evaluation of Impact Damage Tolerance in Carbon Fabric/epoxy-matrix Composites by Electrical Resistance Measurement

    Institute of Scientific and Technical Information of China (English)

    LI Zhipeng; XIE Xiaolin; HONG Zhen; LU Chao; WANG Gaochao

    2012-01-01

    Impact damage tolerance is provided in intensity design on composites.The compression intensity of impacted composites requires more than 60% of its original intensity.The influence of impact on compressive intensity and electrical resistance of carbon fabric/epoxy-matrix composites was studied in this paper.The experimental results shows that impact can cause damage in composites,degenerate compressive intensity,and increase resistance.The electrical resistance change rate was used as an evaluation indicator of impact damage tolerance of composites.Impact damage,which results from the applying process of composites,can be identified in time by electrical resistance measurement.So,the safety performance of composites can also be improved.

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

    Science.gov (United States)

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

    2007-03-01

    For getting information about the distribution of chemical composition, several model polymers were prepared under different polymerization conditions and were measured by critical adsorption point-liquid chromatography (CAP-LC). In the copolymer system of 8- and 9- (4-oxatricyclo[5.2.1.0 2,6]decane-3-one) acrylate (OTDA) and 2-ethyl-2-adamantyl methacrylate (EAdMA), the peak shapes of the CAP-LC chromatogram varied according to the polymerization condition although they indicated same molecular weight and averaged chemical composition. The difference of the CAP-LC elution curves was related to the chemical composition distribution of copolymers for CAP-LC measurement combined with proton nuclear magnetic resonance (1H-NMR). The terpolymers consisted of α-hydroxy-γ-butyrolactone methacrylate (GBLMA), 2-methyl-2-adamantyl methacrylate (MAdMA) and 1-hydroxy-3-adamantyl methacrylate (HAdMA) were prepared under various polymerization conditions. In the terpolymer system that had same molecular weight and average chemical composition, the solubility parameter (δ) and the dissolution rate were measured. The δ value and the dissolution rate curve were different among these terpolymers. It was suggested that the δ value and the chemical composition distribution of these terpolymers have a significant influence on the lithographic performance.

  20. Higgs Discovery: Impact on Composite Dynamics [Thinking Fast and Slow

    CERN Document Server

    Sannino, Francesco

    2013-01-01

    I discuss the impact of the discovery of a Higgs-like state on composite dynamics starting by critically examining the reasons in favour of either an elementary or composite nature of this state. Accepting the standard model interpretation I re-address the standard model vacuum stability within a Weyl-consistent computation. I will carefully examine the fundamental reasons why what has been discovered might not be the standard model Higgs. Dynamical electroweak breaking naturally addresses a number of the fundamental issues unsolved by the standard model interpretation. However this paradigm has been challenged by the discovery of a not-so-heavy Higgs-like state. I will therefore review the recent discovery \\cite{Foadi:2012bb} that the standard model top-induced radiative corrections naturally reduce the intrinsic non-perturbative mass of the composite Higgs state towards the desired experimental value. Not only we have a natural and testable working framework but we have also suggested specific gauge theorie...

  1. On the Formation and Chemical Composition of Super Earths

    CERN Document Server

    Alessi, Matthew; Cridland, Alex J

    2016-01-01

    Super Earths are the largest population of exoplanets and are seen to exhibit a rich diversity of compositions as inferred through their mean densities. Here we present a model that combines equilibrium chemistry in evolving disks with core accretion that tracks materials accreted onto planets during their formation. In doing so, we aim to explain why super Earths form so frequently and how they acquire such a diverse range of compositions. A key feature of our model is disk inhomogeneities, or planet traps, that act as barriers to rapid type-I migration. The traps we include are the dead zone, which can be caused by either cosmic ray or X-ray ionization, the ice line, and the heat transition. We find that in disks with sufficiently long lifetimes ($\\gtrsim$ 4 Myr), all traps produce Jovian planets. In these disks, planet formation in the heat transition and X-ray dead zone produces hot Jupiters while the ice line and cosmic ray dead zones produce Jupiters at roughly 1 AU. Super Earth formation takes place wi...

  2. Nanoscale chemical interaction enhances the physical properties of bioglass composites.

    Science.gov (United States)

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

    2013-10-22

    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 (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.

  3. Chemical Composition and Antioxidant Capacity of Brazilian Passiflora Seed Oils.

    Science.gov (United States)

    de Santana, Fernanda Carvalho; Shinagawa, Fernanda Branco; Araujo, Elias da Silva; Costa, Ana Maria; Mancini-Filho, Jorge

    2015-12-01

    The seed oils of different varieties of 4 Passiflora species cultivated in Brazil were analyzed and compared regarding their physicochemical parameters, fatty acid composition and the presence of minor components, such as phytosterols, tocopherols, total carotenoids, and phenolic compounds. The antioxidant capacities of the oil extracts were determined using the 2,2'azinobis [3-ethylbenzothiazoline-6-sulfonic acid] and oxygen radical absorbance capacity methods. The results revealed that all studied Passiflora seed oils possessed similar physicochemical characteristics, except for color, and predominantly contained polyunsaturated fatty acids with a high percentage of linolenic acid (68.75% to 71.54%). Other than the total phytosterol content, the extracted oil from Passiflora setacea BRS Pérola do Cerrado seeds had higher quantities (% times higher than the average of all samples), of carotenoids (44%), phenolic compounds (282%) and vitamin E (215%, 56%, 398%, and 100% for the α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol isomers, respectively). The methanolic extracts from Passiflora setacea BRS Pérola do Cerrado seed oil also showed higher antioxidant activity, which was positively correlated with the total phenolic, δ-tocopherol, and vitamin E contents. For the first time, these results indicate that Passiflora species have strong potential regarding the use of their seeds for oil extraction. Due to their interesting composition, the seed oils may be used as a raw material in manufacturing industries in addition to other widely used vegetable oils.

  4. An estimate of the chemical composition of Titan's lakes

    CERN Document Server

    Cordier, D; Lunine, J -I; Lavvas, P; Vuitton, V

    2009-01-01

    Hundreds of radar-dark patches interpreted as lakes have been discovered in the north and south polar regions of Titan. We have estimated the composition of these lakes by using the direct abundance measurements from the Gas Chromatograph Mass Spectrometer (GCMS) aboard the Huygens probe and recent photochemical models based on the vertical temperature profile derived by the Huygens Atmospheric Structure Instrument (HASI). Thermodynamic equilibrium is assumed between the atmosphere and the lakes, which are also considered as nonideal solutions. We find that the main constituents of the lakes are ethane (C2H6) (~76-79%), propane (C3H8) (~7-8%), methane (CH4) (~5-10%), hydrogen cyanide (HCN) (~2-3%), butene (C4H8) (~1%), butane (C4H10) (~1%) and acetylene (C2H2) (~1%). The calculated composition of lakes is then substantially different from what has been expected from models elaborated prior to the exploration of Titan by the Cassini-Huygens spacecraft.

  5. Chemical Compositions of Kinematically Selected Outer Halo Stars

    CERN Document Server

    Zhang, Lan; Aoki, Wako; Zhao, Gang; Chiba, Masashi

    2009-01-01

    Chemical abundances of 26 metal-poor dwarfs and giants are determined from high-resolution and high signal-to-noise ratio spectra obtained with Subaru/HDS. The sample is selected so that most of the objects have outer-halo kinematics. Self-consistent atmospheric parameters were determined by an iterative procedure based on spectroscopic analysis. Abundances of 13 elements, including $\\alpha$-elements (Mg, Si, Ca, Ti), odd-Z light elements (Na, Sc), iron-peak elements (Cr, Mn, Fe, Ni, Zn) and neutron-capture elements (Y, Ba), are determined by two independent data reduction and LTE analysis procedures, confirming the consistency of the stellar parameters and abundances results. We find a decreasing trend of [$\\alpha$/Fe] with increasing [Fe/H] for the range of $-3.5 <$ [Fe/H]$ < -1$, as found by Stephens and Boesgaard (2002). [Zn/Fe] values of most objects in our sample are slightly lower than the bulk of halo stars previously studied. These results are discussed as possible chemical properties of the ou...

  6. Chemical composition of fresh snowfalls at Palmer Station, Antarctica

    Science.gov (United States)

    DeFelice, T. P.

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

  7. Chemical composition of meat in two cyprinid species

    Directory of Open Access Journals (Sweden)

    Valerica Macovei

    2009-06-01

    Full Text Available The biochemical analyses of the meat were determined in two species of carps, respectively Cyprinus carpio and Ctenopharyngodon idella. We worked on four groups of 10 fishes each (two groups for C. carpio and two groups for Ct. idella. One group from both species was fed with special fodder, and the other two groups were fed with clover (Trifolium pratense and reeds (Phragmites communis for C. carpio and Ct. idella respectively. The determination was made in the laboratory of chemical analyses of the Faculty of Animal Sciences, University of Agricultural Sciences and Veterinary Medicine Iaşi and we determined the content of the meat in proteins, fat, dry substance and minerals. The characteristic chemicals of the meat were determined on the extracted sample from the lateral musculature of the body. Biochemical analysis of meat from the four carp lots shows that protein content of meat is higher in groups which received combined feed compared to group which individuals were fed with natural food. Therefore, in case of feeding fish with combined fodder the protein content of meat increases, which proves a good recovery of protein in feed. Fat content and minerals in cyprinid meat are both higher in individuals fed with combined feed compared to those fed with natural components. When fat content in meat is higher, the dry matter content in meat is higher.

  8. Experimental Study on Impact-Induced Reaction Characteristics of PTFE/Ti Composites Enhanced by W Particles

    Directory of Open Access Journals (Sweden)

    Yan Li

    2017-02-01

    Full Text Available Metal/fluoropolymer composites are a category of energetic structural materials that release energy through exothermic chemical reactions initiated under highly dynamic loadings. In this paper, the chemical reaction mechanism of PTFE (polytetrafluoroethylene/Ti/W composites is investigated through thermal analysis and composition analysis. These composites undergo exothermic reactions at 510 °C to 600 °C, mainly producing TiFx. The tungsten significantly reduces the reaction heat due to its inertness. In addition, the dynamic compression properties and impact-induced reaction behaviors of PTFE/Ti/W composites with different W content prepared by pressing and sintering are studied using Split Hopkinson Pressure Bar and high speed photography. The results show that both the mechanical strength and the reaction degree are significantly improved with the increasing strain rate. Moreover, as W content increases, the mechanical strength is enhanced, but the elasticity/plasticity is decreased. The PTFE/Ti/W composites tend to become more inert with the increasing W content, which is reflected by the reduced reaction degree and the increased reaction threshold for the impact ignition.

  9. Investigation on Impact Strength Properties of Kevlar Fabric using Different Shear Thickening Fluid Composition

    Directory of Open Access Journals (Sweden)

    R. Joselin

    2014-05-01

    Full Text Available Great interest has aroused in developing high impact resistant fabrics based on the incorporation of a shear thickening fluid (STF into high performance fabrics (Kevlar. This work developed a shear thickening fluid enhanced fabrics and the influence of the shear thickening fluid types against spike impact and the impact resistance performance were investigated. Silica nano-particle impregnated Kevlar fabrics exhibit significantly enhanced ballistic performance while retaining flexibility. It was found that fabrics impregnated with functionalized nanoparticles offer multiple resistance to the penetration of a sharp impactor. The improvement in protection is traced by the formation of siloxane bonds during functionalization. It exhibits significant improvement in shear stiffness and aslight increase in tensile stiffness. The impact strength properties of all samples were tested using impact testingand quasi-static testing apparatuses. Chemical compositions and microscopic structures were analyzed with Fouriertransform infrared spectroscopy and scanning electron microscopy. The current study clearly displays a significant enhancement in penetration resistance of Kevlar fabric impregnated with different combination of STF’s.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 236-243, DOI:http://dx.doi.org /10.14429/dsj.64.7322

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

    Science.gov (United States)

    Voudrias, Evangelos; Goudakou, Lambrini; Kermenidou, Marianthi; Softa, Aikaterini

    2012-07-01

    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

  11. A New Reference Chemical Composition for TMC-1

    CERN Document Server

    Gratier, P; Ohishi, M; Roueff, E; Loison, J -C; Hickson, K M; Wakelam, V

    2016-01-01

    Recent detections of complex organic molecules in dark clouds have rekindled interest in the astrochemical modeling of these environments. Because of its relative closeness and rich molecular complexity, TMC-1 has been extensively observed to study the chemical processes taking place in dark clouds. We use local thermodynamical equilibrium radiative transfer modeling coupled with a Bayesian statistical method which takes into account outliers to analyze the data from the Nobeyama spectral survey of TMC-1 between 8 and 50 GHz. We compute the abundance relative to molecular hydrogen of 57 molecules, including 19 isotopologues in TMC-1 along with their associated uncertainty. The new results are in general agreement with previous abundance determination from Ohishi & Kaifu and the values reported in the review from Agundez & Wakelam. However, in some cases, large opacity and low signal to noise effects allow only upper or lower limits to be derived, respectively.

  12. Chemical composition of umbu (Spondias tuberosa Arr. Cam seeds

    Directory of Open Access Journals (Sweden)

    Soraia Vilela Borges

    2007-02-01

    Full Text Available The umbu tree (Spondias tuberosa Arr. Cam is an important fruit tree the economy of the semi-arid northeastern region of Brazil. With the objective of finding use for the seeds, physical and chemical characterizations of the seeds from 2 cultivars in 2 maturation stages were carried out and their fatty acid and mineral profiles determined. The results showed no differences between the seeds analyzed. The yield was about 10% and the dimensions as follows: length from 1.48 to 2.11 cm and width from 0.76 to 1.16 cm. The average lipid content was 55% of which 69% was unsaturated and the average protein content was 24%. The seeds were a good source of the following minerals: P, K, Mg, Fe and Cu. The overall results indicated that the oil or the seeds could be used for food stuffs if no toxic agents were found.

  13. A New Reference Chemical Composition for TMC-1

    Science.gov (United States)

    Gratier, P.; Majumdar, L.; Ohishi, M.; Roueff, E.; Loison, J. C.; Hickson, K. M.; Wakelam, V.

    2016-08-01

    Recent detections of complex organic molecules in dark clouds have rekindled interest in the astrochemical modeling of these environments. Because of its relative closeness and rich molecular complexity, TMC-1 has been extensively observed to study the chemical processes taking place in dark clouds. We use local thermodynamical equilibrium radiative transfer modeling coupled with a Bayesian statistical method which takes into account outliers to analyze the data from the Nobeyama spectral survey of TMC-1 between 8 and 50 GHz. We compute the abundance relative to molecular hydrogen of 57 molecules, including 19 isotopologues in TMC-1 along with their associated uncertainty. The new results are in general agreement with previous abundance determination from Ohishi & Kaifu and the values reported in the review from Agúndez & Wakelam. However, in some cases, large opacity and low signal to noise effects allow only upper or lower limits to be derived, respectively.

  14. CHEMICAL COMPOSITION AND ANTI-INFLAMMATORY ACTIVITY OF Roldana platanifolia

    Directory of Open Access Journals (Sweden)

    Amira Arciniegas

    2015-11-01

    Full Text Available The chemical study of Roldana platanifolia led to the isolation of β-caryophyllene, five eremophilanolides, chlorogenic acid, and a mixture of β-sitosterol-stigmasterol, β-sitosteryl glucopyranoside, and sucrose. The anti-inflammatory activities of the extracts and isolated products were tested using the 12-O-tetradecanoylphorbol-13-acetate (TPA model of induced acute inflammation. The acetone and methanol extracts showed dose dependent activities (ID50 0.21 and 0.32 mg/ear, respectively, while none of the isolated compounds exhibited relevant edema inhibition. The active extracts were also evaluated with the myeloperoxidase assay technique (MPO to determine their ability to prevent neutrophil infiltration. Results showed that the anti-inflammatory activity was related to the compound’s ability to inhibit pro-inflammatory mediators such as neutrophils.

  15. Pressure impact of autoclave treatment on water sorption and pectin composition of flax cellulosic-fibres.

    Science.gov (United States)

    Alix, S; Colasse, L; Morvan, C; Lebrun, L; Marais, S

    2014-02-15

    The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In order to reduce the water absorption of this non-woven technical fibres, an autoclave treatment was performed which was expected to remove the pectins and then to reduce the water sorption on their negative charges. The impact of autoclave pressure (0.5, 1 and 2 bars) on water sorption was investigated by using a gravimetric static equilibrium method. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. The lowest pressure treatments impacted only the Langmuir contribution while the 2 bar autoclave-treatment positively impacted the water resistance in the core of fibres by reducing Henry's absorption rate. This was shown to be related to the chemical modifications at the surface and in the core of fibres. A schematic model is presented relating the water sorption and the pectic composition of the fabric.

  16. Epigenome: A Biomarker or Screening Tool to Evaluate Health Impact of Cumulative Exposure to Chemical and Non-Chemical Stressors.

    Science.gov (United States)

    Olden, Kenneth; Lin, Yu-Sheng; Bussard, David

    2016-06-01

    Current risk assessment practices and toxicity information are hard to utilize for assessing the health impact of combined or cumulative exposure to multiple chemical and non-chemical stressors encountered in the "real world" environment. Non-chemical stressors such as heat, radiation, noise, humidity, bacterial and viral agents, and social factors, like stress related to violence and socioeconomic position generally cannot be currently incorporated into the risk assessment paradigm. The Science and Decisions report released by the National Research Council (NRC) in 2009 emphasized the need to characterize the effects of multiple stressors, both chemical and non-chemical exposures. One impediment to developing information relating such non-chemical stressors to health effects and incorporating them into cumulative assessment has been the lack of analytical tools to easily and quantitatively monitor the cumulative exposure to combined effects of stressors over the life course.

  17. Indirect Determination of Chemical Composition and Fuel Characteristics of Solid Waste

    DEFF Research Database (Denmark)

    Riber, Christian; Christensen, Thomas Højlund

    Determination of chemical composition of solid waste can be performed directly or indirectly by analysis of combustion products. The indirect methodology instrumented by a full scale incinerator is the only method that can conclude on elements in trace concentrations. These elements are of great...... interest in evaluating waste management options by for example LCA modeling. A methodology description of indirect determination of chemical composition and fuel properties of waste is provided and validated by examples. Indirect analysis of different waste types shows that the chemical composition...... of toxic elements is shown exemplified by Hg. The average concentration is evaluated to be affected by three occurrences; background, rare items and very rare items (1/800 tonnes), that are all important to the Hg average concentration....

  18. Tharsis Formation by Chemical Plume Due to Giant Impact Event

    Science.gov (United States)

    Fleck, J.; Weeraratne, D. S.; Olson, P.

    2014-12-01

    Tharsis formed early in the history of Mars, likely during the Noachian but later than the hemispheric crustal dichotomy that it partially overprints (Johnson and Phillips, 2005; Solomon et al., 2005; Wenzel et al., 2004). It has been suggested that the crustal dichotomy may have been formed by a giant impact (Andrews-Hanna et al., 2008; Marinova et al., 2008; Nimmo et al., 2008). Several models have been proposed to explain a localized orogeny, but predict multiple, evenly-spaced plumes or have instability growth and rise times which are longer than Tharsis formation. We use fluid dynamic experiments to model the differentiation process during Mars accretion using low viscosity glucose syrup solutions and an emulsion of liquid gallium for the metal-rich magma ocean and a high viscosity glucose syrup for the mantle. Our experiments demonstrate the formation of metal-silicate diapirs from metal emulsion drops that form a pond at the base of the magma ocean. The diapirs descend through the underlying mantle with trailing conduit of low viscosity silicate material. The silicate material is buoyant and eventually ascends back through the conduit. Remaining emulsion drops that do not adhere with the diapir fall through the conduit, forcing the buoyant molten silicate material to exit the conduit laterally and ascend along a new trajectory. The time elapsed between diapir formation and ascent of the chemical plume in experiments scales with the time between the formation of the crustal dichotomy on Mars and the formation of Tharsis. Our model offers an explanation for the rapid formation of Tharsis on the edge of the crustal dichotomy via a single large upwelling event followed by smaller upwellings producing and the late stages of effusive volcanism observed in the Tharsis region.

  19. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    OpenAIRE

    Ernstoff, Alexi; Trier, Xenia; JOLLIET Oliver; Fantke, Peter

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through migration of chemicals from the packaging into the food product. We build a framework based on a life cycle perspective to predict which chemicals may be in a package that are not intentionally added i...

  20. Comparison of different methods for extraction from Tetraclinis articulata: yield, chemical composition and antioxidant activity.

    Science.gov (United States)

    Herzi, Nejia; Bouajila, Jalloul; Camy, Séverine; Romdhane, Mehrez; Condoret, Jean-Stéphane

    2013-12-15

    In the present study, three techniques of extraction: hydrodistillation (HD), solvent extraction (conventional 'Soxhlet' technique) and an innovative technique, i.e., the supercritical fluid extraction (SFE), were applied to ground Tetraclinis articulata leaves and compared for extraction duration, extraction yield, and chemical composition of the extracts as well as their antioxidant activities. The extracts were analyzed by GC-FID and GC-MS. The antioxidant activity was measured using two methods: ABTS(•+) and DPPH(•). The yield obtained using HD, SFE, hexane and ethanol Soxhlet extractions were found to be 0.6, 1.6, 40.4 and 21.2-27.4 g/kg respectively. An original result of this study is that the best antioxidant activity was obtained with an SFE extract (41 mg/L). The SFE method offers some noteworthy advantages over traditional alternatives, such as shorter extraction times, low environmental impact, and a clean, non-thermally-degraded final product. Also, a good correlation between the phenolic contents and the antioxidant activity was observed with extracts obtained by SFE at 9 MPa.

  1. Gymnema sylvestre R. Br., an Indian medicinal herb: traditional uses, chemical composition, and biological activity.

    Science.gov (United States)

    Di Fabio, Giovanni; Romanucci, Valeria; Di Marino, Cinzia; Pisanti, Antonio; Zarrelli, Armando

    2015-01-01

    Gymnema sylvestre R. Br. is one of the most important medicinal plants that grows in tropical forests in India and South East Asia. Its active ingredients and extracts of leaves and roots are used in traditional medicine to treat various ailments and they are present in the market for pharmaceutical and parapharmaceutical products. Commercial products based on substances of plant origin that are generally connoted as natural have to be subjected to monitoring and evaluation by health authorities for their potential impacts on public health. The monitoring and evaluation of these products are critical because the boundary between a therapeutic action and a functional or healthy activity has not yet been defined in a clear and unambiguous way. Therefore, these products are considered borderline products, and they require careful and rigorous studies, in order to use them as complement and/or even replacement of synthetic drugs that are characterized by side effects and high economic costs. This review explores the traditional uses, chemical composition and biological activity of G. sylvestre extracts, providing a general framework on the most interesting extracts and what are the necessary studies for a complete definition of the range of activities.

  2. Chemical composition, fatty acid profile and bioactive compounds of guava seeds (Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Ana Maria Athayde Uchôa-thomaz

    2014-09-01

    Full Text Available This study aimed to characterize the chemical composition, determine the fatty acid profile, and quantify the bioactive compounds present in guava seed powder (Psidium guajava L.. The powder resulted from seeds obtained from guava pulp processing. The agro-industrial seeds from red guava cv. paluma were used, and they were donated by a frozen pulp fruit manufacturer. They contain varying amounts of macronutrients and micronutrients, with a high content of total dietary fiber (63.94 g/100g, protein (11.19 g/100g, iron (13.8 mg/100g, zinc (3.31 mg/100g, and reduced calorie content (182 kcal/100g. Their lipid profile showed a predominance of unsaturated fatty acids (87.06%, especially linoleic acid (n6 and oleic acid (n9. The powder obtained contained significant amounts of bioactive compounds such as ascorbic acid (87.44 mg/100g, total carotenoids (1.25 mg/100 g and insoluble dietary fiber (63.55 g/100g. With regard to their microbiological quality, the samples were found suitable for consumption. Based on these results, it can be concluded that the powder produced has favorable attributes for industrial use, and that use of these seeds would be a viable alternative to prevent various diseases and malnutrition in our country and to reduce the environmental impact of agricultural waste.

  3. Chemical compositions of fine particulate organic matter emitted from Chinese cooking.

    Science.gov (United States)

    Zhao, Yunliang; Hu, Min; Slanina, Sjaak; Zhang, Yuanhang

    2007-01-01

    Food cooking can be a significant source of atmospheric particulate organic matter. In this study, the chemical composition of particulate organic matter (POM) in PM2.5 emitted from four different Chinese cooking styles were examined by gas chromotography-mass spectrometry (GC-MS). The identified species are consistent in the emissions from different Chinese cooking styles and the quantified compounds account for 5-10% of total POM in PM2.5. The dominant homologue is fatty acids, constituting 73-85% of the quantified compounds. The pattern of n-alkanes and the presence of beta-sitosterol and levoglucosan indicate that vegetables are consumed during Chinese cooking operations. Furthermore, the emissions of different compounds are impacted significantly by the cooking ingredients. The candidates of organic tracers used to describe and distinguish emissions from Chinese cooking in Guangzhou are tetradecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, levoglucosan, mannosan, galactosan, nonanal, and lactones. During the sampling period, the relative contribution of Chinese cooking to the mass concentration of atmospheric hexadecanoic acid should be less than 1.3% in Guangzhou.

  4. Chemical composition and sources of particle pollution in affluent and poor neighborhoods of Accra, Ghana

    Science.gov (United States)

    Zhou, Zheng; Dionisio, Kathie L.; Verissimo, Thiago G.; Kerr, Americo S.; Coull, Brent; Arku, Raphael E.; Koutrakis, Petros; Spengler, John D.; Hughes, Allison F.; Vallarino, Jose; Agyei-Mensah, Samuel; Ezzati, Majid

    2013-12-01

    The highest levels of air pollution in the world now occur in developing country cities, where air pollution sources differ from high-income countries. We analyzed particulate matter (PM) chemical composition and estimated the contributions of various sources to particle pollution in poor and affluent neighborhoods of Accra, Ghana. Elements from earth’s crust were most abundant during the seasonal Harmattan period between late December and late January when Saharan dust is carried to coastal West Africa. During Harmattan, crustal particles accounted for 55 μg m-3 (37%) of fine particle (PM2.5) mass and 128 μg m-3 (42%) of PM10 mass. Outside Harmattan, biomass combustion, which was associated with higher black carbon, potassium, and sulfur, accounted for between 10.6 and 21.3 μg m-3 of fine particle mass in different neighborhoods, with its contribution largest in the poorest neighborhood. Other sources were sea salt, vehicle emissions, tire and brake wear, road dust, and solid waste burning. Reducing air pollution in African cities requires policies related to energy, transportation and urban planning, and forestry and agriculture, with explicit attention to impacts of each strategy in poor communities. Such cross-sectoral integration requires emphasis on urban environment and urban poverty in the post-2015 Development Agenda.

  5. Chemical Composition of Different Botanical Origin Honeys Produced by Sicilian Black Honeybees (Apis mellifera ssp. sicula).

    Science.gov (United States)

    Mannina, Luisa; Sobolev, Anatoly P; Di Lorenzo, Arianna; Vista, Silvia; Tenore, Gian Carlo; Daglia, Maria

    2015-07-01

    In 2008 a Slow Food Presidium was launched in Sicily (Italy) for an early warning of the risk of extinction of the Sicilian native breed of black honeybee (Apis mellifera L. ssp sicula). Today, the honey produced by these honeybees is the only Sicilian honey produced entirely by the black honeybees. In view of few available data regarding the chemical composition of A. mellifera ssp. sicula honeys, in the present investigation the chemical compositions of sulla honey (Hedysarum coronarium L.) and dill honey (Anethum graveolens L.) were studied with a multimethodological approach, which consists of HPLC-PDA-ESI-MSn and NMR spectroscopy. Moreover, three unifloral honeys (lemon honey (obtained from Citrus limon (L.) Osbeck), orange honey (Citrus arantium L.), and medlar honey (Eriobotrya japonica (Thunb.) Lindl)), with known phenol and polyphenol compositions, were studied with NMR spectroscopy to deepen the knowledge about sugar and amino acid compositions.

  6. Effects of the cooling rate on the shear behavior of continuous glass fiber/impact polypropylene composites (GF-IPP)

    KAUST Repository

    Wafai, Husam

    2016-09-20

    Fiber-reinforced composites with improved dissipation of energy during impact loading have recently been developed based on a polypropylene copolymer commonly called impact polypropylene (IPP). Composites made of IPP reinforced with glass fibers (GF) are particularly attractive to the automotive industry due to their low cost and good impact resistance. In such composites, the cooling rate varies depending on processing techniques and manufacturing choices. Here, we study the effects of the cooling rate of GF-IPP composites on shear behavior, which is critical in impact applications, using [±45]s monotonic and cyclic (load/unload) tensile specimens. The specimens were manufactured under a wide range of cooling rates (3 °C/min, 22 °C/min, 500–1000 °C/min). Mainly dominated by the properties of the matrix, the global shear behavior of GF-IPP composites differed considerably with respect to the cooling rate. However, the performance of the fiber-matrix interface (chemically modified) appeared to be unaffected by the range of cooling rates used in this study. We found that the cooling rate has a minor effect on the rate of damage accumulation, while it strongly modifies the shear-activated rate-dependant viscoelastic behavior. © 2016 Elsevier Ltd

  7. Chemical composition of a sample of bright solar-metallicity stars

    CERN Document Server

    Caffau, E; Steffen, M; Bonifacio, P; Strassmeier, K G; Gallagher, A; Faraggiana, R; Sbordone, L

    2015-01-01

    We present a detailed analysis of seven young stars observed with the spectrograph SOPHIE at the Observatoire de Haute-Provence for which the chemical composition was incomplete or absent in the literature. For five stars, we derived the stellar parameters and chemical compositions using our automatic pipeline optimized for F, G, and K stars, while for the other two stars with high rotational velocity, we derived the stellar parameters by using other information (parallax), and performed a line-by-line analysis. Chromospheric emission-line fluxes from CaII are obtained for all targets. The stellar parameters we derive are generally in good agreement with what is available in the literature. We provide a chemical analysis of two of the stars for the first time. The star HIP 80124 shows a strong Li feature at 670.8 nm implying a high lithium abundance. Its chemical pattern is not consistent with it being a solar sibling, as has been suggested.

  8. Inorganic Chemical Composition of Swimming Pools in Amman-Jordan

    Directory of Open Access Journals (Sweden)

    Bety Saqarat

    2012-10-01

    Full Text Available Monitoring was carried out during summer 2011 in three types of swimming pools in Amman-Jordan. Thirty six water samples, collected from three users type of swimming pools (adults, family and infants, were examined for its major ionic composition (HCO3-, Cl-, NO3-, SO4=, Ca+2, Mg+2, Na+, K+ and PO4+4 in addition to its BOD and COD content. All of the examined samples from the swimming pools water were acceptable according to the local and WHO standards. The type and number of users as well as the maintenance of the swimming pool water influenced the water quality. The results showed that there was a noticeable increase in NO3, PO4 and Cl than other ions. All of the examined samples from the swimming pools water were acceptable according to the local and WHO standards and although the water of the infant’s users changed frequently, it showed the highest concentration of most of the parameters and Adults’ pool showed the lowest.

  9. Disentangling Hot Jupiters formation location from their chemical composition

    CERN Document Server

    Ali-Dib, Mohamad

    2016-01-01

    We use a population synthesis model that includes pebbles and gas accretion, planetary migration, and simplified chemistry scheme to study the formation of hot-Jupiters. Models have proposed that these planets can either originate beyond the snowline and then move inward via disk migration, or form "in-situ" inside the snowline. The goal of this work is to verify which of these two scenarios is more compatible with pebbles accretion, and if can we distinguish observationally between them via the resulting planetary C/O ratios and core masses. Our results show that, for solar system composition, the C/O ratios will vary but weakly between the two populations, since a significant amount of carbon and oxygen are locked up in refractories. In this case, we find a strong correlation between the carbon abundance and core mass. The C/O ratio variations are more pronounced in the case where we assume that all carbon and oxygen are in volatiles. On average, Hot-Jupiters forming "in-situ" inside the snowline will have ...

  10. Brazilian Red Propolis—Chemical Composition and Botanical Origin

    Directory of Open Access Journals (Sweden)

    Andreas Daugsch

    2008-01-01

    Full Text Available 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.

  11. Characterization of biomass burning particles: chemical composition and processing

    Science.gov (United States)

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

    2003-12-01

    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.

  12. The chemical composition of Galactic ring nebulae around massive stars

    CERN Document Server

    Esteban, C; Morisset, C; Garcia-Rojas, J

    2016-01-01

    We present deep spectra of ring nebulae associated with Wolf-Rayet (WR) and O-type stars: NGC 6888, G2.4+1.4, RCW 58, S 308, NGC 7635 and RCW 52. The data have been taken with the 10m Gran Telescopio Canarias and the 6.5m Clay Telescope. We extract spectra of several apertures in some of the objects. We derive C$^{++}$ and O$^{++}$ abundances from faint recombination lines in NGC 6888 and NGC 7635, permitting to derive their C/H and C/O ratios and estimate the abundance discrepancy factor (ADF) of O$^{++}$. The ADFs are larger than the typical ones of normal HII regions but similar to those found in the ionised gas of star-forming dwarf galaxies. We find that chemical abundances are rather homogeneous in the nebulae where we have spectra of several apertures: NGC 6888, NGC 7635 and G2.4+1.4. We obtain very high values of electron temperature in a peripheral zone of NGC 6888, finding that shock excitation can reproduce its spectral properties. We find that all the objects associated with WR stars show N enrich...

  13. Application of chemical vapor composites (CVC) to terrestrial thermionics

    Science.gov (United States)

    Miskolczy, Gabor; Reagan, Peter

    1995-01-01

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

  14. Antimicrobial, antioxidant activities and chemical composition of selected Thai spices

    Directory of Open Access Journals (Sweden)

    Juraithip Wungsintaweekul

    2010-12-01

    Full Text Available Nine volatile oils and six methanol extracts from Ocimum americanum, O. basilicum, O. sanctum, Citrus hystrix,Alpinia galanga, Curcuma zedoaria, Kaempferia parviflora and Zingiber cassumunar were assessed for antimicrobial andantioxidant activities. The volatile oils and extracts were investigated against eight bacteria and three fungi. The resultsillustrated that O. americanum volatile oil exhibited broad spectrum activity against tested bacteria with the MICs ranging1.4-3.6 mg/ml and Candida spp. with the MICs ranging from 0.5-0.6 mg/ml. The O. sanctum volatile oil showed a considerableactivity against only Candida spp. with the MICs ranging from 0.8-1.4 mg/ml. Interestingly, growth of Mycobacteriumphlei was inhibited by the volatiles of O. americanum, C. hystrix peel, and C. zedoaria with MIC of 1.7, 3.5 and 1.2 mg/ml,respectively. For antioxidant activity evaluation, the methanol extracts of C. hystrix (leaf and peel and K. parviflora hadpotent antioxidant activity by the radical-scavenging DPPH method with IC50 of 24.6, 66.3 and 61.5 mg/ml, respectively.GC-MS analysis revealed the typical chemical profiles of the volatile oils. The major component showed the characteristicsof the volatile oils and was probably responsible for the antimicrobial effect.

  15. Conical intersection seams in polyenes derived from their chemical composition

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-21

    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.

  16. Conical intersection seams in polyenes derived from their chemical composition

    Science.gov (United States)

    Nenov, Artur; de Vivie-Riedle, Regina

    2012-08-01

    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)], 10.1063/1.3608924. 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.

  17. Structure of the chondrules and the chemical composition of olivine in meteorite Jesenice

    Directory of Open Access Journals (Sweden)

    Bojan Ambrožič

    2013-06-01

    Full Text Available This paper presents a mineralogical analysis of various chondrule types and chemical analysis of olivine indifferent parts of meteorite Jesenice. Quantitative energy-dispersive X-ray spectroscopy with a scanning electronmicroscope was used in the analyses. The results showed that the chemical composition of the olivine was homogeneousthroughout the meteorite with an average olivine composition of Fa 26.4 ± 0.6. The results of this study werein agreement with previous study of the meteorite, which showed that the meteorite Jesenice was an equilibratedL chondrite.

  18. Essential Oils from Thyme (Thymus vulgaris): Chemical Composition and Biological Effects in Mouse Model.

    Science.gov (United States)

    Vetvicka, Vaclav; Vetvickova, Jana

    2016-12-01

    Thymus species are popular spices and contain volatile oils as main chemical constituents. Recently, plant-derived essential oils are gaining significant attention due to their significant biological activities. Seven different thymus-derived essential oils were compared in our study. First, we focused on their chemical composition, which was followed up by testing their effects on phagocytosis, cytokine production, chemotaxis, edema inhibition, and liver protection. We found limited biological activities among tested oils, with no correlation between composition and biological effects. Similarly, no oils were effective in every reaction. Based on our data, the tested biological use of these essential oils is questionable.

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

    Science.gov (United States)

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

    2009-12-09

    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.

  20. Chemical Composition Variability of Essential Oils of Daucus gracilis Steinh. from Algeria.

    Science.gov (United States)

    Benyelles, Batoul; Allali, Hocine; El Amine Dib, Mohamed; Djabou, Nassim; Paolini, Julien; Costa, Jean

    2017-02-17

    The chemical compositions of 20 Algerian Daucus gracilis essential oils were investigated using GC-FID, GC/MS, and NMR analyses. Altogether, 47 compounds were identified, accounting for 90-99% of the total oil compositions. The main components were linalool (18; 12.5-22.6%), 2-methylbutyl 2-methylbutyrate (20; 9.2-20.2%), 2-methylbutyl isobutyrate (10; 4.2-12.2%), ammimajane (47; 2.6-37.1%), (E)-β-ocimene (15; 0.2-12.8%) and 3-methylbutyl isovalerate (19; 3.3-9.6%). The chemical composition of the essential oils obtained from separate organs was also studied. GC and GC/MS analysis of D. gracilis leaves and flowers allowed identifying 47 compounds, amounting to 92.3% and 94.1% of total oil composition, respectively. GC and GC/MS analysis of D. gracilis leaf and flower oils allowed identifying linalool (22.7%), 2-methylbutyl 2-methylbutyrate (18.9%), 2-methylbutyl isovalerate (13.6%), ammimajane (10.4%), 3-methylbutyl isovalerate (10.3%), (E)-β-ocimene (8.4%) and isopentyl 2-methylbutyrate (8.1%) as main components. The chemical variability of the Algerian oil samples was studied using statistical analysis, which allowed the discrimination of three main Groups. A direct correlation between the altitudes, nature of soils and the chemical compositions of the D. gracilis essential oils was evidenced. This article is protected by copyright. All rights reserved.

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

    Science.gov (United States)

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

    2007-05-01

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

  2. Milk yield and chemical composition of sheep milk in Srednostaroplaninska and Tetevenska breeds

    OpenAIRE

    Gerchev G.; Mihaylova G.

    2012-01-01

    The study was conducted from April to July on pastures located at different altitudes and of different sward composition during the milking period of Srednostaroplaninska and Tetevenska sheep. Morning bulk milk was sampled for analysis monthly between April and end of July. The purpose of the study was to establish the milk yield and to investigate the chemical composition of sheep milk obtained from Srednostaroplaninska and Tetevenska breeds reared on past...

  3. Physico-Chemical, Functional and Rheological Characterization of Biodegradable Pellets and Composite Sheets

    OpenAIRE

    Jan Kulsum; Jan Shumaila; Riar CS; Saxena DC

    2016-01-01

    Deoiled rice bran, paddy husk, cashew nut shell liquid and glycerol were extruded into pellets and further pressed into composites. Processing and plasticizer type had significant effect on physico-chemical, functional, rheological and morphological properties of pellets and composites. Specific mechanical energy of the pellets containing cashew nut shell liquid as plasticizer was higher than those containing glycerol. The maximum hardness and bulk density were obtained for pellets prepared f...

  4. Hanford enhanced waste glass characterization. Influence of composition on chemical durability

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-06-01

    This report provides a review of the complete high-level waste (HLW) and low-activity waste (LAW) data sets for the glasses recently fabricated at Pacific Northwest National Laboratory and characterized at Savannah River National Laboratory (SRNL). The review is from the perspective of relating the chemical durability performance to the compositions of these study glasses, since the characterization work at SRNL focused on chemical analysis and ASTM Product Consistency Test (PCT) performance.

  5. Antioxidant capacity and chemical composition in seeds rich in omega-3: chia, flax, and perilla

    OpenAIRE

    Sheisa Cyléia Sargi; Beatriz Costa Silva; Hevelyse Munise Celestino Santos; Paula Fernandes Montanher; Joana Schuelter Boeing; Oscar Oliveira Santos Júnior; Nilson Evelázio de Souza; Jesuí Vergílio Visentainer

    2013-01-01

    The chemical composition and antioxidant capacity of five seeds, chia, golden flax, brown flax, white perilla, and brown perilla, were determined. The chemical properties analyzed included moisture, ash, crude protein, carbohydrates, total lipids, fatty acids, and antioxidant capacity (ABTS•+, DPPH•, and FRAP). The results showed the highest amounts of protein and total lipids in brown and white perilla. Perilla and chia showed higher amounts of alpha-linolenic fatty acid than those of flaxse...

  6. Ballistic Impact on Glass/Epoxy Composite Laminates

    Directory of Open Access Journals (Sweden)

    R. Velmurugan

    2014-07-01

    Full Text Available Glass/epoxy composite laminates are subjected to impact loading and the energy absorbing capacity of the laminates is studied. In the present study, laminates with four different orientations and thickness values are considered. Analytical study is carried out based on energy method and results are compared with FE results obtained from Abaqus/Explicit software. Results obtained from the analytical methods are showing good agreement with the FE results. It is found that cross-ply laminates are most efficient in ballistic resistance when compared with the laminates of other orientations. It is also noticed that the energy absorbing capacity is decreasing with increase in velocity of the projectile for a given lay-up and thickness value.Defence Science Journal, Vol. 64, No. 4, July 2014, pp. 393-399, DOI:http://dx.doi.org/10.14429/dsj.64.3882 

  7. Impact of Binder Composition on Inkjet Printing Paper

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2015-01-01

    Full Text Available This article is focused on the impact of different binder mixtures on the performances of paper surface and printability. The coating properties were studied with the chosen silica pigment, and the binder consisted of vinyl acetate copolymer and polyvinyl alcohol with different ratios, followed by the measurement of smoothness, whiteness, and surface strength. The inkjet image quality was assessed using water-based inks. The print density, dot gain, and line quality were analyzed. The results showed that the surface performance and printability were affected by the composition of the binder. With the decrease of vinyl acetate copolymer and the increase of polyvinyl alcohol, the surface smoothness and strength decreased, and the penetration and diffusion of the ink changed as well. When the binder mixture was used with proper ratio, a larger solid density, smaller dot gain, and higher definition can be achieved, which were better than using either one of them alone.

  8. NGC 6388: Chemical Composition of Its Eight Cool Giants

    Science.gov (United States)

    Wallerstein, G.; Kovtyukh, V. V.; Andrievsky, S. M.

    2007-04-01

    Eight cool giants in the unusual globular cluster NGC 6388 have been investigated in order to derive their elemental abundances. Effective temperatures from 3500 to 3850 K were derived using the method of line-depth ratios. Surface gravities were derived in two ways. Spectroscopic gravities, derived by the requirement that the abundance of iron be the same from Fe I and Fe II lines, were rather low, ranging from -0.3 to 0.0. Photometric gravities, derived from the assumed stellar mass of 0.7 Modot and the luminosity and Teff of the stars, fell between +0.25 and +0.70. Mean [Fe/H] values were -0.8 for spectroscopic gravities and -0.6 for photometric gravities. A test using spectra of the same resolution of the two coolest red giants in the globular cluster M4 obtained at the Apache Point Observatory were analyzed for comparison with the definitive analysis of Ivans et al. (1999). The very cool metal-poor red giant HD 232078 was also analyzed for comparison with the analysis of Gonzalez & Wallerstein (1998). Both comparisons showed that our methods yield the same abundance scale as previous works. We have compared the composition of stars in NGC 6388 with those of K giants with similar [Fe/H] in 47 Tuc and the Galactic bulge. The observed value of [O/Fe] is near zero, which is less than in 47 Tuc and bulge stars of similar metallicity. The α-elements behave similarly to oxygen and show only small excesses at about the same level as do the α-elements in the globular clusters associated with the Sgr system. It is unclear whether these differences are responsible for the unusual color-magnitude diagram of NGC 6388.

  9. Chemical composition of nuts and seeds sold in Korea.

    Science.gov (United States)

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

    2013-04-01

    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.

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

    Science.gov (United States)

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

    2009-01-01

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

  11. Chemical composition of atmospheric aerosols between Moscow and Vladivostok

    Directory of Open Access Journals (Sweden)

    S. Kuokka

    2007-05-01

    Full Text Available 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 μm 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 μg m−3 with an average of 21.6 μg 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

  12. Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

    OpenAIRE

    Jaqueline Albano de Morais; Renan Gadioli; Marco-Aurelio De Paoli

    2016-01-01

    Abstract Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate), EVA, to recover the impact resistance of high density polyethylene, ...

  13. DAMAGE PROGRESSIVE MODEL OF COMPRESSION OF COMPOSITE LAMINATES AFTER LOW VELOCITY IMPACT

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiao-quan; LI Zheng-neng

    2005-01-01

    Compressive properties of composite laminates after low velocity impact are one of the most serious circumstances that must be taken into account in damage tolerance design of composite structures. In order to investigate compressive properties of composite laminates after low velocity impact, three dimensional dynamic finite element method (FEM) was used to simulate low-velocity impact damage of 2 kinds of composite laminates firstly. Damage distributions and projective damage areas of the laminates were predicted under two impact energy levels. The analyzed damage after impact was considered to be the initial damage of the laminates under compressive loads. Then three dimensional static FEM was used to simulate the compressive failure process and to calculate residual compressive strengths of the impact damaged laminates. It is achieved to simulate the whole process from initial low-velocity impact damage to final compressive failure of composite laminates. Compared with experimental results, it shows that the numerical predicting results agree with the test results fairly well.

  14. Decadal trends in aerosol chemical composition at Barrow, Alaska: 1976–2008

    Directory of Open Access Journals (Sweden)

    G. E. Shaw

    2009-11-01

    Full Text Available Aerosol measurements at Barrow, Alaska during the past 30 years have identified the long range transport of pollution associated with Arctic Haze as well as ocean-derived aerosols of more local origin. Here, we focus on measurements of aerosol chemical composition to assess (1 trends in Arctic Haze aerosol and implications for source regions, (2 the interaction between pollution-derived and ocean-derived aerosols and the resulting impacts on the chemistry of the Arctic boundary layer, and (3 the response of aerosols to a changing climate. Aerosol chemical composition measured at Barrow, AK during the Arctic haze season is compared for the years 1976–1977 and 1997–2008. Based on these two data sets, concentrations of non-sea salt (nss sulfate (SO4= and non-crustal (nc vanadium (V have decreased by about 60% over this 30 year period. Consistency in the ratios of nss SO4=/ncV and nc manganese (Mn/ncV between the two data sets indicates that, although emissions have decreased in the source regions, the source regions have remained the same over this time period. The measurements from 1997–2008 indicate that, during the haze season, the nss SO4= aerosol at Barrow is becoming less neutralized by ammonium (NH4+ yielding an increasing sea salt aerosol chloride (Cl deficit. The expected consequence is an increase in the release of Cl atoms to the atmosphere and a change in the lifetime of volatile organic compounds (VOCs including methane. In addition, summertime concentrations of biogenically-derived methanesulfonate (MSA and nss SO4= are increasing at a rate of 12 and 8% per year, respectively. Further research is required to assess the environmental factors behind the increasing concentrations of biogenic aerosol.

  15. Decadal trends in aerosol chemical composition at Barrow, AK: 1976–2008

    Directory of Open Access Journals (Sweden)

    P. K. Quinn

    2009-09-01

    Full Text Available Aerosol measurements at Barrow, AK during the past 30 years have identified the long range transport of pollution associated with Arctic Haze as well as ocean-derived aerosols of more local origin. Here, we focus on measurements of aerosol chemical composition to assess 1 trends in Arctic Haze aerosol and implications for source regions, 2 the interaction between pollution-derived and ocean-derived aerosols and the resulting impacts on the chemistry of the Arctic boundary layer, and 3 the response of aerosols to a changing climate. Aerosol chemical composition measured at Barrow, AK during the Arctic haze season is compared for the years 1976–1977 and 1997–2008. Based on these two data sets, concentrations of non-sea salt (nss sulfate (SO4= and non-crustal (nc vanadium (V have decreased by about 60% over this 30 year period. Consistency in the ratios of nss SO4=/ncV and nc manganese (Mn/ncV between the two data sets indicates that, although emissions have decreased in the source regions, the source regions have remained the same over this time period. The measurements from 1997–2008 indicate that, during the haze season, the nss SO4= aerosol at Barrow is becoming less neutralized by ammonium (NH4+ yielding an increasing sea salt aerosol chloride (Cl deficit. The expected consequence is an increase in the release of Cl atoms to the atmosphere and a change in the lifetime of volatile organic compounds (VOCs including methane. In addition, summertime concentrations of biogenically-derived methanesulfonate (MSA and nss SO4= are increasing at a rate of 12 and 8% per year, respectively. Further research is required to assess the environmental factors behind the increasing concentrations of biogenic aerosol.

  16. The Chemical Composition of Surface Waters of Technogenically Affected Geo-Systems in the Eastern Donbas Region

    Directory of Open Access Journals (Sweden)

    Olga S. Reshetnyak

    2014-11-01

    Full Text Available Based on an analysis of literary data and the author’s own research findings, the paper assesses the factors in the formation of the chemical composition of surface and subterranean waters and the variability of the chemical composition and quality of river waters in the eastern Donbas region. The author illustrates that the major negative effect of the impact of technogenic waters on river waters is salinization. The paper points up a high level of pollution in river waters with a broad spectrum of metal compounds, among which the biggest threat comes from Fegen, Al, Mn, Cu, and Sr, which is of a steady nature. The quality of water in the majority of rivers in the eastern Donbas region is evaluated as Quality Class 4 – dirty and/or very dirty. The findings can be used in resolving a whole array of scientific and applied objectives related to assessing the migration of chemical substances and the level of pollution in surface and subterranean waters and forecasting the condition of water sites and the quality of water, as well as in carrying out water-protection activities in the region.

  17. Compaction of an Oxisol and chemical composition of palisadegrass

    Directory of Open Access Journals (Sweden)

    Eurico Lucas de Sousa Neto

    2013-08-01

    Full Text Available Compaction is an important problem in soils under pastoral land use, and can make livestock systems unsustainable. The objective of this research was to study the impact of soil compaction on yield and quality of palisade (UROCHLOA BRIZANTHA cv. Marandu. The experiment was conducted on an Oxisol in the State of Mato Grosso, Brazil. Treatments consisted of four levels of soil compaction: no compaction (NC, slight compaction (SC, medium compaction (MC and high compaction (HC. The following soil properties were evaluated (layers 0-0.05 and 0.05-0.10 m: aggregate size distribution, bulk density (BD, macroporosity, microporosity, total porosity (TP, relative compaction (RC, and the characteristics of crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF and dry matter yield (DMY of the forage. Highly compacted soil had high BD and RC, and low TP (0-0.05 m. Both DMY and CP were affected by HC, and both were strongly related to BD. Higher DMY (6.96 Mg ha-1 and CP (7.8 % were observed in the MC treatment (BD 1.57 Mg m-3 and RC 0.91 Mg m-3, in 0-0.05 m. A high BD of 1.57 Mg m-3 (0-0.05 m did not inhibit plant growth. The N concentration in the palisade biomass differed significantly among compaction treatments, and was 8.72, 11.20, 12.48 and 10.98 g kg-1 in NC, SC, MC and HC treatments, respectively. Increase in DMY and CP at the MC level may be attributed to more absorption of N in this coarse-textured soil.

  18. [Application of near infrared reflectance spectroscopy to predict meat chemical compositions: a review].

    Science.gov (United States)

    Tao, Lin-Li; Yang, Xiu-Juan; Deng, Jun-Ming; Zhang, Xi

    2013-11-01

    In contrast to conventional methods for the determination of meat chemical composition, near infrared reflectance spectroscopy enables rapid, simple, secure and simultaneous assessment of numerous meat properties. The present review focuses on the use of near infrared reflectance spectroscopy to predict meat chemical compositions. The potential of near infrared reflectance spectroscopy to predict crude protein, intramuscular fat, fatty acid, moisture, ash, myoglobin and collagen of beef, pork, chicken and lamb is reviewed. This paper discusses existing questions and reasons in the current research. According to the published results, although published results vary considerably, they suggest that near-infrared reflectance spectroscopy shows a great potential to replace the expensive and time-consuming chemical analysis of meat composition. In particular, under commercial conditions where simultaneous measurements of different chemical components are required, near infrared reflectance spectroscopy is expected to be the method of choice. The majority of studies selected feature-related wavelengths using principal components regression, developed the calibration model using partial least squares and modified partial least squares, and estimated the prediction accuracy by means of cross-validation using the same sample set previously used for the calibration. Meat fatty acid composition predicted by near-infrared spectroscopy and non-destructive prediction and visualization of chemical composition in meat using near-infrared hyperspectral imaging and multivariate regression are the hot studying field now. On the other hand, near infrared reflectance spectroscopy shows great difference for predicting different attributes of meat quality which are closely related to the selection of calibration sample set, preprocessing of near-infrared spectroscopy and modeling approach. Sample preparation also has an important effect on the reliability of NIR prediction; in particular

  19. The Diversity of Chemical Composition and the Effects on Stellar Evolution and Planetary Habitability

    Science.gov (United States)

    Truitt, Amanda; Young, Patrick A.

    2017-01-01

    For my dissertation under the supervision of Dr. Young, I investigate how stars of different mass and composition evolve, and how stellar evolution impacts the location of the habitable zone around a star. Current research into habitability of exoplanets focuses mostly on the concept of the classical HZ - the range of distances from a star over which liquid water could exist on a planet's surface - determined primarily by the host star's luminosity and spectral characteristics. With the ever-accelerating discovery of new exoplanets, it is imperative to develop a more complete understanding of what factors play a role in creating the “habitable” conditions of a planet. I discuss how stellar evolution is integral to how we define a HZ, and how this work will apply to the search for habitable Earth-like planets in the future.I developed a catalog of stellar evolution models for Sun-like stars with variable compositions; masses range from 0.1-1.2 Msol (spectral types M4-F4) at scaled metallicities of 0.1-1.5 Zsol, and O/Fe, C/Fe, and Mg/Fe values of 0.44-2.28, 0.58-1.72, and 0.54-1.84, respectively. I use a spread in abundance values based on observations of variability in nearby stars. It is important to understand how specific elements (and not just total metallicity) can impact evolutionary lifetime. The time-dependent HZ boundaries have also been calculated for each stellar track. Additionally, I recently created a grid of models for M-dwarfs, and I am currently working to make preliminary estimates of stellar activity vs. age for each representative star in the catalog.My results indicate that to gauge the habitability potential of a given system, both the evolutionary history as well as the detailed chemical characterization of the host star must be considered. This work can be used to assess whether a planet discovered in the HZ of its star has had sufficient time to develop a biosphere capable of producing detectable biosignatures. The catalog is designed

  20. Effects and Signatures of Thermal and Compositional Mantle Anomalies Induced by Giant Impacts on Mars

    Science.gov (United States)

    Ruedas, T.; Breuer, D.

    2016-08-01

    Fully dynamical convection models coupled with a petrological model are combined with a parameterized formulation of impact effects to model how the thermal and compositional anomalies generated by impacts influence the evolution of Mars.

  1. On the life time prediction of repeatedly impacted thermoplastic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Mustafa Ozguer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey)], E-mail: ozgur_bora@yahoo.com; Coban, Onur [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Sinmazcelik, Tamer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); TUBITAK-MAM, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey); Cuerguel, Ismail [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Guenay, Volkan [TUBITAK-MAM, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey)

    2009-01-15

    Impact-fatigue properties of unidirectional carbon fibre reinforced polyetherimide (PEI) composites were investigated. Low velocity repeated impacts were performed by using pendulum type instrumented impact tester (Ceast, Resil 25) at energy levels ranging 0.54-0.94 J. Samples were prepared according to ISO 180 and subjected to repeated low velocity impacts up to fracture by the hammer. Results of repeated impact study are reported in terms of peak load (F{sub max}), absorbed energy (E{sub max}) and number of repeated impacts. An analytical model to describe the life time of composite materials subjected to repeated impact loadings was presented.

  2. Impact of aerosol composition on cloud condensation nuclei activity

    Directory of Open Access Journals (Sweden)

    Q. Zhang

    2012-04-01

    Full Text Available The impact of aerosol composition on cloud condensation nuclei (CCN activity were analyzed in this study based on field experiments carried out at downtown Tianjin, China in September 2010. In the experiments, the CCN measurements were performed at supersaturation (SS of 0.1%, 0.2% and 0.4% using a thermal-gradient diffusion chamber (DMT CCNC, whereas the aerosol size distribution and composition were simultaneously measured with a TSI SMPS and an Aerodyne Aerosol Mass Spectrometer (AMS, respectively. The results show that the influence of aerosol composition on CCN activity is notable under low SS (0.1%, and their influence decreased with increasing SS. For example, under SS of 0.1%, the CCN activity increases from 4.5±2.6% to 12.8±6.1% when organics fraction decrease from 30–40% to 10–20%. The rate of increase reached up to 184%. While under SS of 0.4%, the CCN activity increases only from 35.7±19.0% to 46.5±12.3% correspondingly. The calculated NCCN based on the size-resolved activation ratio and aerosol number size distribution correlated well with observed NCCN at high SS (0.4%, but this consistence decreased with the falling of SS. The slopes of linear fitted lines between calculated and observed NCCN are 0.708, 0.947, and 0.995 at SS of 0.1%, 0.2% and 0.4% respectively. Moreover, the stand deviation (SD of calculated NCCN increased with the decreasing of SS. A case study of CCN closure analyses indicated that the calculated error of NCCN could reach up to 34% at SS of 0.1% if aerosol composition were not included, and the calculated error decreased with the raising of SS. It is decreased to 9% at SS of 0.2%, and further decreased to 4% at SS of 0.4%.

  3. Impact of aerosol composition on cloud condensation nuclei activity

    Directory of Open Access Journals (Sweden)

    Q. Zhang

    2012-01-01

    Full Text Available The impact of aerosol composition on cloud condensation nuclei (CCN activity was analyzed in this study based on field experiments carried out at downtown Tianjin, China, in September 2010. In the experiments, the CCN measurements were performed at supersaturation (SS of 0.1%, 0.2% and 0.4% using a thermal-gradient diffusion chamber (DMT CCNC, whereas the aerosol size distribution and composition were simultaneously measured with a TSI SMPS and an Aerodyne Aerosol Mass Spectrometer (AMS, respectively. The results show that the influence of aerosol composition on CCN activity is notable under low SS (0.1%, and their influence decreased with increasing SS. For example, under SS of 0.1%, the CCN activity increases from 4.5 ± 2.6% to 12.8 ± 6.1% when organics fraction decrease from 30–40% to 10–20%. The rate of increase reaches up to 184%. While under SS of 0.4%, the CCN activity increases only from 35.7 ± 19.0% to 46.5 ± 12.3%, correspondingly. The calculated NCCN based on the size-resolved activation ratio and aerosol number size distribution correlates well with observed NCCN at high SS (0.4%, but this correlation decreases with the falling of SS. The slopes of linear fitted lines between calculated and observed NCCN are 0.708, 0.947, and 0.995 at SS of 0.1%, 0.2% and 0.4%, respectively. Moreover, the standard deviation (SD of calculated NCCN increases with the decreasing of SS. A case study of CCN closure analyses indicates that the calculated error of NCCN can reach up to 34% at SS of 0.1% if aerosol composition is not included, and the calculated error decreases with the raising of SS. It decreases to 9% at SS of 0.2%, and further decreases to 4% at SS of 0.4%.

  4. Lantana montevidensis Essential Oil: Chemical Composition and Mosquito Repellent Activity against Aedes aegypti

    Science.gov (United States)

    The essential oil (EO) of Lantana montevidensis (Spreng.) Briq. (L. sellowiana Link & Otto) was investigated for its chemical composition and mosquito repellent activity. The essential oil obtained by hydrodistillation of aerial plant parts was analyzed by GC-FID and GC-MS. The major constituents we...

  5. Discerning the Chemical Composition and Mutagenic Effects of Soy Biodiesel PM

    Science.gov (United States)

    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...

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

    Science.gov (United States)

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

  7. A survey on the microbiological and chemical composition of buffalo milk in China

    NARCIS (Netherlands)

    Han, B.Z.; Meng, Y.; Li, M.; Yang, Y.; Ren, F.; Zeng, Q.; Nout, M.J.R.

    2007-01-01

    One hundred and twelve samples of raw buffalo milk were collected at four locations in China, and their microbiological and chemical composition was analyzed. Average levels of major components were: fat 7.59% (v/v), crude protein 4.86% (w/w), lactose 4.74% (w/w), total solids 18.44% (w/w), ash 0.85

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

    Science.gov (United States)

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

    2007-03-01

    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.

  9. Thermo-chemical simulation of a composite offshore vertical axis wind turbine blade

    DEFF Research Database (Denmark)

    Baran, Ismet; Tutum, Cem Celal; Hattel, Jesper Henri

    2012-01-01

    In the present study three dimensional steady state thermo-chemical simulation of a pultrusion process is investigated by using the finite element/nodal control volume (FE/NCV) technique. Pultrusion simulation of a composite having a C-shaped cross section is performed as a validation case...

  10. Effects of diet on the chemical composition of migratory locusts (Locusta migratoria)

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Poel, van der A.F.B.

    2011-01-01

    An experiment was conducted to determine the effects of diet on the chemical composition of migratory locusts (Locusta migratoria L.). Fresh and dry weight and the contents of dry matter, ash, lipid, protein, Ca, K, Mg, Na, P, Cu, Fe, Zn, retinol, lutein, zeaxanthine, cryptoxanthin, carotenes, lycop

  11. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean-potential impacts

    NARCIS (Netherlands)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier Gon, H.A.C. van der

    2010-01-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size dis

  12. Chemically aged and mixed aerosols over the Central Atlantic Ocean - Potential impacts

    NARCIS (Netherlands)

    Astitha, M.; Kallos, G.; Spyrou, C.; O'Hirok, W.; Lelieveld, J.; Denier Gon, H.A.C. van der

    2010-01-01

    Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size dis

  13. Chemical composition, functional and sensory characteristics of wheat-taro composite flours and biscuits.

    Science.gov (United States)

    Himeda, Makhlouf; Njintang Yanou, Nicolas; Fombang, Edith; Facho, Balaam; Kitissou, Pierre; Mbofung, Carl M F; Scher, Joel

    2014-09-01

    The physicochemical, alveographic and sensory characteristics of precooked taro-wheat composite flours and their biscuits were investigated. A 2x7 factorial design consisting of two varieties of taro flour (Red Ibo Ngaoundere, RIN, and egg-like varieties) and 7 levels of wheat substitutions (0, 5, 10, 15, 20, 25 and 30 %) was used for this purpose. It was observed that water absorption capacity (range 95-152 g/100 g), water solubility index (range 18.8-29.5 g/100 g) and swelling capacity (range 125.4-204.6 mL/100 g) of composite flours significantly (p < 0.05) increased with increase in taro level. Conversely the dough elasticity index (range 59.8-0 %), extensibility (78-22 mm) and strength (range 281-139 × 10(-4) joules) significantly (p < 0.05) diminished with increase in wheat substitution. Up to 10 % substitution with RIN taro flour and 15 % with egg-like taro flour, the composite taro-wheat dough exhibited elasticity indices acceptable for the production of baking products, whereas at all levels of taro substitution, the composite biscuits samples were either acceptable as or better (5-10 % substitution with RIN flour) than 100 % wheat biscuit.

  14. Cuticle Structure in Relation to Chemical Composition: Re-assessing the Prevailing Model

    Science.gov (United States)

    Fernández, Victoria; Guzmán-Delgado, Paula; Graça, José; Santos, Sara; Gil, Luis

    2016-01-01

    The surface of most aerial plant organs is covered with a cuticle that provides protection against multiple stress factors including dehydration. Interest on the nature of this external layer dates back to the beginning of the 19th century and since then, several studies facilitated a better understanding of cuticular chemical composition and structure. The prevailing undertanding of the cuticle as a lipidic, hydrophobic layer which is independent from the epidermal cell wall underneath stems from the concept developed by Brongniart and von Mohl during the first half of the 19th century. Such early investigations on plant cuticles attempted to link chemical composition and structure with the existing technologies, and have not been directly challenged for decades. Beginning with a historical overview about the development of cuticular studies, this review is aimed at critically assessing the information available on cuticle chemical composition and structure, considering studies performed with cuticles and isolated cuticular chemical components. The concept of the cuticle as a lipid layer independent from the cell wall is subsequently challenged, based on the existing literature, and on new findings pointing toward the cell wall nature of this layer, also providing examples of different leaf cuticle structures. Finally, the need for a re-assessment of the chemical and structural nature of the plant cuticle is highlighted, considering its cell wall nature and variability among organs, species, developmental stages, and biotic and abiotic factors during plant growth. PMID:27066059

  15. CHEMICAL COMPOSITION VARIABILITY IN THE Uncaria tomentosa (cat’s claw WILD POPULATION

    Directory of Open Access Journals (Sweden)

    Evelyn Maribel Condori Peñaloza

    2015-03-01

    Full Text Available Uncaria tomentosa (cat's claw is a vine widely distributed throughout the South-American rainforest. Many studies investigating the chemical composition of cat's claw have focused on the pentacyclic (POA and tetracyclic oxindole alkaloids (TOA, quinovic acid glycosides (QAG, and polyphenols (PPH. Nevertheless, it is still uncertain how environmental factors affect chemical groups. The aim of this work was to better understand the influence of environmental factors (geographic origin, altitude, and season on cat's claw chemical composition. Stem bark, branches and leaf samples were extracted and analyzed by HPLC-PDA. The data obtained were explored by multivariate analysis (HCA and PCA. Higher amounts of oxindole alkaloids and PPH were found in leaves, followed by stem bark and branches. No clear relationship was verified among geographic origin or altitude and chemical composition, which remained unchanged regardless of season (dry or rainy. However, three oxindole alkaloid chemotypes were clearly recognized: chemotype I (POA with cis D/E ring junction; chemotype II (POA with trans D/E ring junction; and chemotype III (TOA. Thus, environmental factors appear to have only a minor influence on the chemical heterogeneity of the cat's claw wild population. Nevertheless, the occurrence of different chemotypes based on alkaloid profiles seems to be clear.

  16. EFFECT OF THERMAL TREATMENT ON THE CHEMICAL COMPOSITION AND MECHANICAL PROPERTIES OF BIRCH AND ASPEN

    Directory of Open Access Journals (Sweden)

    Duygu Kocaefe

    2008-05-01

    Full Text Available The high temperature treatment of wood is one of the alternatives to chemical treatment. During this process, the wood is heated to higher temperatures than those of conventional drying. The wood structure changes due to decomposition of hemicelluloses, ramification of lignin, and crystallization of cellulose. The wood becomes less hygroscopic. These changes improve the dimensional stability of wood, increase its resistance to micro-organisms, darken its color, and modify its hardness. However, wood also might loose some of its elasticity. Consequently, the heat treatment conditions have to be optimized. Therefore, it is important to understand the transformation of the chemical structure of wood caused by the treatment. In this study, the modification of the surface composition of the wood was followed with Fourier transform infrared spectroscopy (FTIR and inverse gas chromatography (IGC under different experimental conditions. The effect of maximum treatment temperatures on the chemical composition of Canadian birch and aspen as well as the correlations between their chemical transformation and different mechanical properties are presented. FTIR analysis results showed that the heat treatment affected the chemical composition of birch more compared to that of aspen. The results of IGC tests illustrated that the surfaces of the aspen and birch became more basic with heat treatment. The mechanical properties were affected by degradation of hemicellulose, ramification of lignin and cellulose crystallization.

  17. Cuticle structure in relation to chemical composition: re-assessing the prevailing model

    Directory of Open Access Journals (Sweden)

    Victoria eFernandez

    2016-03-01

    Full Text Available The surface of most aerial plant organs is covered with a cuticle that provides protection against multiple stress factors including dehydration. Interest on the nature of this external layer dates back to the beginning of the 19th century and since then, several studies facilitated a better understanding of cuticular chemical composition and structure. The prevailing undertanding of the cuticle as a lipidic, hydrophobic layer which is independent from the epidermal cell wall underneath stems from the concept developed by Brongniart and von Mohl during the first half of the 19th century. Such early investigations on plant cuticles attempted to link chemical composition and structure with the existing technologies, and have not been directly challenged for decades. Beginning with a historical overview about the development of cuticular studies, this review is aimed at critically assessing the information available on cuticle chemical composition and structure, considering studies performed with cuticles and isolated cuticular chemical components. The concept of the cuticle as a lipid layer independent from the cell wall is subsequently challenged, based on the existing literature, and on new findings pointing towards the cell wall nature of this layer, also providing examples of different leaf cuticle structures. Finally, the need for a re-assessment of the chemical and structural nature of the plant cuticle is highlighted, considering its cell wall nature and variability among organs, species, developmental stages, and biotic and abiotic factors during plant growth.

  18. The effect of biological and chemical additives on the chemical composition and fermentation process of Dactylis glomerata silage

    Energy Technology Data Exchange (ETDEWEB)

    Alba-Mejía, J.E.; Skladanka, J.; Hilger-Delgado, A.; Klíma, M.; Knot, P.; Doležal, P.; Horky, P.

    2016-11-01

    This study was carried out to determine the chemical composition, silage quality and ensilability of ten cocksfoot cultivars using biological and chemical silage additives. The plant material was harvested from the first and second cut, cultivated at the Research Station of Fodder Crops in Vatín, Czech Republic. Wilted forage was chopped and ensiled in mini-silos with 3 replicates per treatment. The treatments were: 1) without additives, used as a control; 2) with bacterial inoculants; and 3) with chemical preservatives. The results indicated that the year factor (2012-2013) influenced significantly the chemical composition of the silage in both cuts. The use of biological inoculants reduced the content of crude fibre and acid detergent fibre; but it did not influence the content of neutral detergent fibre, in comparison with the control silage in both cuts. Furthermore, the application of biological inoculants reduced the concentration of lactic acid (LA) and acetic acid (AA) in contrast to the control silage in the first cut. Moreover, in the second cut the same values tended to be the opposite. Interestingly, ‘Amera’ was the unique variety that presented a high concentration of butyric acid (0.2%) in comparison with other varieties in the first cut. In conclusion, the biological inoculants had a favourable effect on silage fermentation. Notably, only ‘Greenly’ and ‘Starly’ varieties from the first cut; and ‘Greenly’, ‘Sw-Luxor’, and ‘Otello’ varieties from the second cut were appropriate for ensiling because their pH-values; LA and AA concentrations were ideal according to the parameters of the fermentation process. (Author)

  19. The effect of biological and chemical additives on the chemical composition and fermentation process of Dactylis glomerata silage

    Directory of Open Access Journals (Sweden)

    Jhonny E. Alba-Mejía

    2016-06-01

    Full Text Available This study was carried out to determine the chemical composition, silage quality and ensilability of ten cocksfoot cultivars using biological and chemical silage additives. The plant material was harvested from the first and second cut, cultivated at the Research Station of Fodder Crops in Vatín, Czech Republic. Wilted forage was chopped and ensiled in mini-silos with 3 replicates per treatment. The treatments were: 1 without additives, used as a control; 2 with bacterial inoculants; and 3 with chemical preservatives. The results indicated that the year factor (2012-2013 influenced significantly the chemical composition of the silage in both cuts. The use of biological inoculants reduced the content of crude fibre and acid detergent fibre; but it did not influence the content of neutral detergent fibre, in comparison with the control silage in both cuts. Furthermore, the application of biological inoculants reduced the concentration of lactic acid (LA and acetic acid (AA in contrast to the control silage in the first cut. Moreover, in the second cut the same values tended to be the opposite. Interestingly, ‘Amera’ was the unique variety that presented a high concentration of butyric acid (0.2% in comparison with other varieties in the first cut. In conclusion, the biological inoculants had a favourable effect on silage fermentation. Notably, only ‘Greenly’ and ‘Starly’ varieties from the first cut; and ‘Greenly’, ‘Sw-Luxor’, and ‘Otello’ varieties from the second cut were appropriate for ensiling because their pH-values; LA and AA concentrations were ideal according to the parameters of the fermentation process.

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

    Science.gov (United States)

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

    2010-10-01

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

  1. IMPROVEMENTS IN WOOD THERMOPLASTIC MATRIX COMPOSITE MATERIALS PROPERTIES BY PHYSICAL AND CHEMICAL TREATMENTS

    Directory of Open Access Journals (Sweden)

    Irena Zivkovic

    2016-03-01

    Full Text Available This paper presents a short overview of the developments made in the field of wood thermoplastic composites in terms of surface treatment, flammability, matrix/reinforcement model, properties and application of recycled polymer matrices. The usage of lignocellulosic fibers as reinforcement in composite materials demands well formed interface between the fiber and the matrix. Because of the different nature of reinforcement and matrix components some physical and chemical treatment methods which improve the fiber matrix adhesion were introduced, as well as the improvements of lignocellulosic fibers and thermoplastic polymer matrix based composites flammability characteristics. These physical and chemical treatments influence the hydrophilic character of the lignocellulosic fibers, and therefore change their physical and mechanical properties.

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

    Science.gov (United States)

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

    2014-08-01

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

  3. Chemical synthesis of nanocrystalline ZrO2-SnO2 composite powders

    Institute of Scientific and Technical Information of China (English)

    YANG Huaming; ZHANG Xiangchao; YANG Wuguo; HUANG Chenghuan; QIU Guanzhou

    2004-01-01

    ZrO2-SnO2 composite nanoparticles were prepared by heating the hydrate precursors synthesized by the chemical co-precipitation reaction of ZrOCl2 and SnCl4. The precursors were examined by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The composite powder was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and desorption isotherm (Barrett-Joyner-Halenda method). The average crystal size of the nanoparticle ranges from 15 to 30 nm for the sample containing 5%-25% ZrO2 (mass fraction). Most of the pores in the ZrO2-SnO2 nanoparticles are about 10-20 nm in diameter. The composite powder is promising for chemical sensors.

  4. Chemical composition measurements of the low activity waste (LAW) EPA-Series glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-01

    In this report, the Savannah River National Laboratory provides chemical analysis results for a series of simulated low activity waste glasses provided by Pacific Northwest National Laboratory as part of an ongoing development task. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. A detailed review showed no indications of errors in the preparation or measurement of the study glasses. All of the measured sums of oxides for the study glasses fell within the interval of 100.2 to 100.8 wt %, indicating recovery of all components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %.

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

    CERN Document Server

    Tautvaišienė, G; Berdyugina, S; Ilyin, I; Chorniy, Y

    2012-01-01

    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.

  6. Chemical composition of glass and crystalline phases in coarse coal gasification ash

    Energy Technology Data Exchange (ETDEWEB)

    R.H. Matjie; Zhongsheng Li; Colin R. Ward; David French [Sasol Technology (Pty) Ltd., Sasolburg (South Africa)

    2008-05-15

    A procedure has been developed for determining the chemical composition and relative abundance of the amorphous or glassy material, as well as crystalline phases, present in coarse coal gasification ash, in order to assist in predicting the behaviour of the material in cement/brick/concrete applications. The procedure is based on a combination of quantitative X-ray diffraction (XRD), chemical analysis and electron microprobe studies. XRD analysis indicates that the clinker samples contain a number of crystalline high temperature phases, including anorthite, mullite, cristobalite, quartz and diopside. Quantitative evaluation using Rietveld-based techniques has been used to determine the percentages of both the individual crystalline phases and the glass component. These data were then combined with the chemistry of the crystalline phases and the overall chemical composition of the ash to estimate the chemical composition of the glass phase, which is typically the most abundant component present in the different materials. Although there is some degree of scatter, comparison between the inferred glass composition from XRD and bulk chemistry and actual data on the glass composition using electron microprobe techniques suggest that the two approaches are broadly consistent. The microprobe further indicates that a range of compositions are present in the glassy and crystalline components of the ashes, including Si-Al-rich glass, metakaolin and Fe-Ca-Mg-Ti phases, as well as quartz, anorthite and an aluminophosphate material. Electron microprobe and XRD studies also show that pyrrhotite (FeS), representing a high temperature transformation product of pyrite, is present in some clinker and partially burnt carbonaceous shale samples. 27 refs., 5 figs., 7 tabs.

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

    Science.gov (United States)

    Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

    2015-01-01

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

  8. Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

    Directory of Open Access Journals (Sweden)

    Jorge Reyes-Rivera

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

  9. Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

    Science.gov (United States)

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

    2015-01-01

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

  10. Differences in chemical composition of soil organic carbon resulting from long-term fertilization strategies.

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Fernanda Regina Voltarelli

    2010-12-01

    Full Text Available OBJECTIVES: The aim of the present study was to assess the effect of the exposure to food-simulating liquids prior to brushing simulation on the surface roughness of five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric Ceram. Material and METHODS: Twenty cylinders (5 mm diameter and 4 mm height of each composite were randomly allocated to 4 groups (n=5, according to the food-simulating liquid in which they were immersed for 7 days at 37°C: artificial saliva, heptane, citric acid, and ethanol. After this period, the top surface of composite cylinders was submitted to 7,500 brushing cycles (200 g load. Measurements of the surface roughness (Ra, ¼m were carried out before and after the exposure to the chemicals/brushing simulation. Changes on the morphology of composite surfaces were observed through scanning electron microscopy (SEM. RESULTS: The statistical analysis (ANOVA with cofactor / Tukey's test, α=5% detected a significant interaction between solutions and composite resins. Esthet-X, Filtek Z250 and Tetric Ceram were not affected by the food-simulating liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface roughness findings, demonstrating the negative effect from chemical solutions and mechanical abrasion. CONCLUSIONS: The surface roughness of composite resin materials are differently affected by the food-simulating solutions, depending on the immersion media.

  12. Chemical-garden formation, morphology, and composition. II. Chemical gardens in microgravity.

    Science.gov (United States)

    Cartwright, Julyan H E; Escribano, Bruno; Sainz-Díaz, C Ignacio; Stodieck, Louis S

    2011-04-05

    We studied the growth of metal-ion silicate chemical gardens under Earth gravity (1 g) and microgravity (μg) conditions. Identical sets of reaction chambers from an automated system (the Silicate Garden Habitat or SGHab) were used in both cases. The μg experiment was performed on board the International Space Station (ISS) within a temperature-controlled setup that provided still and video images of the experiment downlinked to the ground. Calcium chloride, manganese chloride, cobalt chloride, and nickel sulfate were used as seed salts in sodium silicate solutions of several concentrations. The formation and growth of osmotic envelopes and microtubes was much slower under μg conditions. In 1 g, buoyancy forces caused tubes to grow upward, whereas a random orientation for tube growth was found under μg conditions.

  13. Prediction of aged red wine aroma properties from aroma chemical composition. Partial least squares regression models.

    Science.gov (United States)

    Aznar, Margarita; López, Ricardo; Cacho, Juan; Ferreira, Vicente

    2003-04-23

    Partial least squares regression (PLSR) models able to predict some of the wine aroma nuances from its chemical composition have been developed. The aromatic sensory characteristics of 57 Spanish aged red wines were determined by 51 experts from the wine industry. The individual descriptions given by the experts were recorded, and the frequency with which a sensory term was used to define a given wine was taken as a measurement of its intensity. The aromatic chemical composition of the wines was determined by already published gas chromatography (GC)-flame ionization detector and GC-mass spectrometry methods. In the whole, 69 odorants were analyzed. Both matrixes, the sensory and chemical data, were simplified by grouping and rearranging correlated sensory terms or chemical compounds and by the exclusion of secondary aroma terms or of weak aroma chemicals. Finally, models were developed for 18 sensory terms and 27 chemicals or groups of chemicals. Satisfactory models, explaining more than 45% of the original variance, could be found for nine of the most important sensory terms (wood-vanillin-cinnamon, animal-leather-phenolic, toasted-coffee, old wood-reduction, vegetal-pepper, raisin-flowery, sweet-candy-cacao, fruity, and berry fruit). For this set of terms, the correlation coefficients between the measured and predicted Y (determined by cross-validation) ranged from 0.62 to 0.81. Models confirmed the existence of complex multivariate relationships between chemicals and odors. In general, pleasant descriptors were positively correlated to chemicals with pleasant aroma, such as vanillin, beta damascenone, or (E)-beta-methyl-gamma-octalactone, and negatively correlated to compounds showing less favorable odor properties, such as 4-ethyl and vinyl phenols, 3-(methylthio)-1-propanol, or phenylacetaldehyde.

  14. Behavior of composite and polycarbonate plate under impact

    Directory of Open Access Journals (Sweden)

    Viot P.

    2010-06-01

    Full Text Available The use of filled composite materials in passive safety structure has significantly increased recently because of their low specific mass, stiffness and energy absorption capacities. However those new light weight materials are supposed to exhibit equal or higher performances than classical ones. Therefore interesting applications by using those materials can be thought about like in the manufacturing of aeronautical helmets. Constituted of an outer shell and an inner foam structure, helmet must protect pilots from an impact by absorbing energy as much as possible and avoid contact between head and impactor. Nowadays different standards describe the minimum required performance for shock attenuation and penetration resistance of helmets [1]. These standards are based on acceleration time history measurements recorded from an accelerometer located at the headform center of mass. For aeronautical standard, acceleration peak value is the only one parameter concerning shock attenuation. Its value must not exceed 300 g, where g = 9.81 m.s-2. Concerning penetration resistance, no contact can be accepted between the penetrating striker and the headform. The outer shell of the helmet has to resist penetration in order to absorb and to extend the input energy over the foam. The most important part of energy is dissipated by polymeric foam through collapse processes under impact [2]. Nevertheless a significant part of energy (one third [3, 4] can be dissipated by the plastic deformation of the shell and the occurrence of damage mechanisms. To obtain different dissipative phenomena, various materials were studied: a Three different kinds of polycarbonate were used. This type of material is well known for its large viscoplastic deformations without any significant hardening. In other words it is a very good candidate for helmet application because of high specific energy dissipation and a stress cut-off effect. Moreover a larger affected zone is expected

  15. Raman spectra of Martian glass analogues: A tool to approximate their chemical composition

    Science.gov (United States)

    Di Genova, Danilo; Kolzenburg, Stephan; Vona, Alessandro; Chevrel, Magdalena Oryaëlle; Hess, Kai-Uwe; Neuville, Daniel R.; Ertel-Ingrisch, Werner; Romano, Claudia; Dingwell, Donald B.

    2016-05-01

    Raman spectrometers will form a key component of the analytical suite of future planetary rovers intended to investigate geological processes on Mars. In order to expand the applicability of these spectrometers and use them as analytical tools for the investigation of silicate glasses, a database correlating Raman spectra to glass composition is crucial. Here we investigate the effect of the chemical composition of reduced silicate glasses on their Raman spectra. A range of compositions was generated in a diffusion experiment between two distinct, iron-rich end-members (a basalt and a peralkaline rhyolite), which are representative of the anticipated compositions of Martian rocks. Our results show that for silica-poor (depolymerized) compositions the band intensity increases dramatically in the regions between 550-780 cm-1 and 820-980 cm-1. On the other hand, Raman spectra regions between 250-550 cm-1 and 1000-1250 cm-1 are well developed in silica-rich (highly polymerized) systems. Further, spectral intensity increases at ~965 cm-1 related to the high iron content of these glasses (~7-17 wt % of FeOtot). Based on the acquired Raman spectra and an ideal mixing equation between the two end-members we present an empirical parameterization that enables the estimation of the chemical compositions of silicate glasses within this range. The model is validated using external samples for which chemical composition and Raman spectra were characterized independently. Applications of this model range from microanalysis of dry and hydrous silicate glasses (e.g., melt inclusions) to in situ field investigations and studies under extreme conditions such as extraterrestrial (i.e., Mars) and submarine volcanic environments.

  16. Nanoscale Mineralogy and Composition of Experimental Regolith Agglutinates Produced under Asteroidal Impact Conditions

    Science.gov (United States)

    Christoffersen, Roy; Cintala, M. J.; Keller, L. P.; See, T. H.; Horz, F.

    2013-01-01

    On the Moon, the energetics of smaller impactors and the physical/chemical characteristics of the granular regolith target combine to form a key product of lunar space weathering: chemically reduced shock melts containing optically-active nanophase Fe metal grains (npFe0) [1]. In addition to forming the optically dark glassy matrix phase in lunar agglutinitic soil particles [1], these shock melts are becoming increasingly recognized for their contribution to optically active patina coatings on a wide range of exposed rock and grain surfaces in the lunar regolith [2]. In applying the lessons of lunar space weathering to asteroids, the potential similarities and differences in regolith-hosted shock melts on the Moon compared to those on asteroids has become a topic of increasing interest [3,4]. In a series of impact experiments performed at velocities applicable to the asteroid belt [5], Horz et al. [6] and See and Horz [7] have previously shown that repeated impacts into a gabbroic regolith analog target can produce melt-welded grain aggregates morphologically very similar to lunar agglutinates [6,7]. Although these agglutinate-like particles were extensively analyzed by electron microprobe and scanning electron microscopy (SEM) as part of the original study [7], a microstructural and compositional comparison of these aggregates to lunar soil agglutinates at sub-micron scales has yet to be made. To close this gap, we characterized a representative set of these aggregates using a JEOL 7600 field-emission scanning electron microscope (FE-SEM), and JEOL 2500SE field-emission scanning transmission electron microscope (FE-STEM) both optimized for energy dispersive X-ray spectroscopy (EDX) compositional spectrum imaging at respective analytical spatial resolutions of 0.5 to 1 micron, and 2 to 4 nm.

  17. Aerosol chemical composition at Cabauw, the Netherlands as observed in two intensive periods in May 2008 and March 2009

    NARCIS (Netherlands)

    Mensah, A.A.; Holzinger, R.; Otjes, R.; Trimborn, A.; Mentel, T.F.; Brink, H. ten; Henzing, B.; Kiendler-Scharr, A.

    2012-01-01

    Observations of aerosol chemical composition in Cabauw, the Netherlands, are presented for two intensive measurement periods in May 2008 and March 2009. Sub-micron aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and is compared to observations from aerosol si

  18. Application of Chemically Accelerated Biotreatment to Reduce Risk in Oil-Impacted Soils

    Energy Technology Data Exchange (ETDEWEB)

    Paterek, J.R.; Bogan, W.W.; Sirivedhin; Tanita

    2003-03-06

    Research was conducted in six major focus areas: (1) Evaluation of the process using 6 test soils with full chemical and physical characteristics to determine controlling factors for biodegradation and chemical oxidation; (2) Determination of the sequestration time on chemical treatment suspectability; (3) Risk factors, i.e. toxicity after chemical and biological treatment; (4) Impact of chemical treatment (Fenton's Reagent) on the agents of biodegradation; (5) Description of a new genus and its type species that degrades hydrocarbons; and (6) Intermediates generate from Fenton's reagent treatment of various polynuclear aromatic hydrocarbons.

  19. Physico-Chemical, Functional and Rheological Characterization of Biodegradable Pellets and Composite Sheets

    Directory of Open Access Journals (Sweden)

    Jan Kulsum

    2016-01-01

    Full Text Available Deoiled rice bran, paddy husk, cashew nut shell liquid and glycerol were extruded into pellets and further pressed into composites. Processing and plasticizer type had significant effect on physico-chemical, functional, rheological and morphological properties of pellets and composites. Specific mechanical energy of the pellets containing cashew nut shell liquid as plasticizer was higher than those containing glycerol. The maximum hardness and bulk density were obtained for pellets prepared from cashew nut shell liquid. Water binding capacity and water solubility index of both pellets and composites were highest for samples containing glycerol as plasticizer. A significant change in functional properties during processing was observed among raw materials, pellets and the final product (composite sheets.

  20. The chemical composition of organic nitrogen in marine rainwater and aerosols

    Science.gov (United States)

    Altieri, K. E.; Hastings, M. G.; Peters, A.; Sigman, D. M.

    2010-12-01

    The current state of knowledge on organic nitrogen in the atmosphere is very limited. Atmospheric water soluble organic nitrogen (WSON) is a subset of the complex water soluble organic matter measured in atmospheric aerosols and rainwater; as such, it impacts cloud condensation processes and aerosol chemical and optical properties. In marine and continental atmospheric deposition, the organic N fraction can be 20-80% of total N potentially influencing receiving ecosystems. Therefore, atmospheric WSON plays an important role in both atmospheric chemistry and the global biogeochemical N cycle. However, the sources (i.e., anthropogenic vs. terrestrial vs. marine), composition (e.g., reduced or oxidized N), potential connections to inorganic N (NO3- and NH4+), and spatio-temporal variability of atmospheric WSON are largely unknown. Samples were collected on or near the island of Bermuda (32.27°N, 64.87°W), which is located in the western North Atlantic and experiences seasonal changes in transport that allow for study of both anthropogenically and primarily marine influenced air masses. Rainwater samples (n=7) and aqueous extracted aerosol samples (n=4) were analyzed by positive ion ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to characterize the chemical composition of the water soluble organic N on a per compound level. We found ~ 800 N containing compounds in 8 compound classes. The CHON+ compound class contained the largest number of N compounds (~ 460). Compared to continental rainwater [Altieri et al., ES&T, 2009], the CHON+ compounds in the marine samples are as dominant in number, yet have less regular patterns and lower O:C ratios for comparable N:C ratios. In fact, average O:C ratios of all N containing compound classes were lower in the marine samples than in continental rainwater samples. No organosulfates or nitrooxy-organosulfates were detected in the marine samples, both of

  1. Influence of Aerosol Chemical Composition on Heterogeneous Ice Formation under Mid-Upper Troposphere Conditions

    Science.gov (United States)

    Kanji, Z. A.; Niemand, M.; Saathoff, H.; Möhler, O.; Chou, C.; Abbatt, J.; Stetzer, O.

    2011-12-01

    Aerosols are involved in cooling/warming the atmosphere directly via interaction with incoming solar radiation (aerosol direct effect), or via their ability to act as cloud condensation or ice nuclei (IN) and thus play a role in cloud formation (indirect effect). In particular, the physical properties of aerosols such as size and solubility and chemical composition can influence their behavior and fate in the atmosphere. Ice nucleation taking place via IN is termed as heterogeneous ice nucleation and can take place with via deposition (ice forming on IN directly from the vapor phase), condensation/immersion (freezing via formation of the liquid phase on IN) or condensation (IN colliding with supercooled liquid drops). This presentation shows how the chemical composition and surface area of various tropospherically relevant aerosols influence conditions of temperature (T) and relative humidity (RH) required for heterogeneous ice formation conditions in the mid-upper troposphere regime (253 - 220K)? Motivation for this comes first from, the importance of being able to predict ice formation accurately so as to understand the hydrological cycle since the ice is the primary initiator of precipitation forming clouds. Second, the tropospheric budget of water vapour, an especially active greenhouse gas is strongly influenced by ice nucleation and growth. Third, ice surfaces in the atmosphere act as heterogeneous surfaces for chemical reactions of trace gases (e.g., SO2, O3, NOx and therefore being able to accurately estimate ice formation rates and quantify ice surface concentrations will allow a more accurate calculation of trace gas budgets in the troposphere. Ice nucleation measurements were conducted using a self-developed continuous flow diffusion chamber and static chamber. A number of tropospherically relevant particulates with naturally-varying and laboratory-modified surface chemistry/structure were investigated for their ice formation efficiency based on highest

  2. Analysis of Particulate and Chemical Residue Resulting from Exposure to Burning and Abrading Composite Materials

    Science.gov (United States)

    2013-05-31

    glass-graphite, and boron -graphite hybrid composites due to combinations of burning and impact. The results were inconclusive regarding threats to...particulates produced in the fire. Physiologic tests were not performed as part of this study, so it cannot be confirmed that the rod-shaped

  3. Risk Assessment for Natural-Hazard Impact on Hazardous Chemical Installations: Workshop Outcome Report

    OpenAIRE

    2016-01-01

    The impact of natural hazards on hazardous installations can cause major chemical accidents. This so-called “Natech” risk is increasing due to industrialisation and climate change. Capacity building in EU Member States, Candidate Countries and EU Neighbourhood Countries on Natech risk required for Natech risk reduction. This report summarises the findings of a training workshop on risk assessment for natural-hazard impact on hazardous chemical installations which the JRC organised in the ...

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

    CERN Document Server

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

    2014-01-01

    Context: The study of chemical abundance patterns in globular clusters is of key importance to constrain the different candidates for intra-cluster pollution of light elements. Aims: We aim at deriving accurate abundances for a large range of elements in the globular cluster 47 Tucanae (NGC 104) to add new constraints to the pollution scenarios for this particular cluster, expanding the range of previously derived element abundances. Methods: Using tailored 1D LTE atmospheric models together with a combination of equivalent width measurements, LTE, and NLTE synthesis we derive stellar parameters and element abundances from high-resolution, high signal-to-noise spectra of 13 red giant stars near the tip of the RGB. Results: We derive abundances of a total 27 elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ru, Ba, La, Ce, Pr, Nd, Eu, Dy). Departures from LTE were taken into account for Na, Al and Ba. We find a mean [Fe/H] = $-0.78\\pm0.07$ and $[\\alpha/{\\rm Fe}]=0.34\\pm0.03$ in...

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

    Science.gov (United States)

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

    2014-12-10

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

  6. Texture Profile Analysis of Sliced Cheese in relation to Chemical Composition and Storage Temperature

    Directory of Open Access Journals (Sweden)

    Yuanrong Zheng

    2016-01-01

    Full Text Available The quantitative relationships among chemical composition, storage temperature, and texture of cheese were not fully understood. In this study, the effects of composition and temperature on textural properties of eight common varieties of sliced cheese were examined. The textural properties of sliced cheeses, including firmness, cohesiveness, adhesiveness, springiness, chewiness, and resilience, were measured by texture profile analysis after storage at 4 and 25°C for 4 h. Multivariate logistic regression models were established to describe the quantitative relationships of textural properties (dependent variables to chemical composition and storage temperature (independent variables of sliced cheeses. Results showed that protein, fat, moisture, and sodium chloride contents as well as storage temperature significantly affected the texture of sliced cheeses (P<0.05. In particular, fat in the dry matter and moisture in the nonfat substances were negatively correlated with firmness of sliced cheeses (P<0.05. As storage temperature rose from 4 to 25°C, the average values of firmness, chewiness, and resilience substantially declined by 42%, 45%, and 17%, respectively (P<0.05. This study provided reference data for adjusting chemical composition and storage temperature of common cheese products to obtain favorable texture for Chinese consumers, which thereby facilitated the localization of cheese industry in Chinese market.

  7. Composite resonances and their impact on the EW chiral Lagrangian

    CERN Document Server

    Sanz-Cillero, J J

    2015-01-01

    In this talk we study the low-energy effective couplings generated by strongly-coupled electroweak models that contain heavy composite resonances. Invariance under $SU(2)_L\\times SU(2)_R$ is a key ingredient in the construction of the resonance action. For simplicity, in these proceedings we focus our attention on the impact of a heavy colourless vector V, which transforms as a triplet under the custodial group. More precisely, we study the couplings that are relevant for the vector form-factors of the L+R current into two electroweak Goldstones and into two Standard Model fermions, which contribute to the oblique parameters S and T and the anomalous $Z\\to f\\bar{f}$ couplings, respectively. Our predictions are compatible with bounds from direct and indirect searches for Mv > 1.5 TeV. Finally, although we consider an antisymmetric tensor formalism to describe the vector resonance, we derive the equivalent action in the Proca four-vector representation and show that the predictions for low-energy couplings and ...

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

    Science.gov (United States)

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

    2014-10-01

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

  9. Electrical Conductivity and Chemical Composition of Soil Solution: Comparison of Solution Samplers in Tropical Soils

    Directory of Open Access Journals (Sweden)

    Davi Lopes do Carmo

    2016-01-01

    Full Text Available ABSTRACT Soil solution samplers may have the same working principle, but they differ in relation to chemical and physical characteristics, cost and handling, and these aspects exert influence on the chemical composition of the soil solution obtained. This study was carried out to evaluate, over time, the chemical composition of solutions extracted by Suolo Acqua, with the hydrophilic membrane (HM as a standard, using soils with contrasting characteristics, and to determine the relationship between electrical conductivity (EC and concentration of ions and pH of soil solution samples. This study was carried out under laboratory conditions, using three soils samples with different clay and organic matter (OM contents. Soil solution contents of F−, Cl−, NO−3, Br−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+, were analyzed, as well as inorganic, organic, and total C contents, pH, and EC, in four successive sampling times. Soil solution chemical composition extracted by the Suolo Acqua sampler is similar to that collected by the HM, but the Suolo Acqua extracted more Na+ and soluble organic C than the HM solution. Solution EC, cation and anion concentrations, and soluble C levels are higher in the soil with greater clay and OM contents (Latossolo and Cambissolo in this case. Soil solution composition varied over time, with considerable changes in pH, EC, and nutrient concentrations, especially associated with soil OM. Thus, single and isolated sampling of the soil solution must be avoided, otherwise composition of the soil solution may not be correctly evaluated. Soil solution EC was regulated by pH, as well as the sum of cation and anion concentrations, and the C contents determined in the soil liquid phase.

  10. Physico-chemical properties of Brazilian cocoa butter and industrial blends. Part I Chemical composition, solid fat content and consistency

    Directory of Open Access Journals (Sweden)

    Ribeiro, A. P. B.

    2012-03-01

    Full Text Available A comparative study of the primary properties of six cocoa butter samples, representative of industrial blends and cocoa butter extracted from fruits cultivated in different geographical areas in Brazil is presented. The samples were evaluated according to fatty acid composition, triacylglycerol composition, regiospecific distribution, melting point, solid fat content and consistency. The results allowed for differentiating the samples according to their chemical compositions, thermal resistance properties, hardness characteristics, as well as technological adequacies and potential use in regions with tropical climates.

    En este trabajo se presenta un estudio comparativo de las propiedades primarias de mantecas de cacao, representativas de las mezclas industriales, y de la manteca de cacao original de diferentes zonas geográficas de Brasil. Las muestras fueron evaluadas de acuerdo a la composición de ácidos grasos, composición de triglicéridos, distribución de los ácidos grasos en las moléculas de triglicéridos, punto de fusión, contenido de grasa sólida y consistencia. Los resultados permitieron diferenciar las muestras por su composición química, propiedades de resistencia térmica, características de dureza, así como en materia de adecuaciones tecnológicas y los usos potenciales en las regiones de clima tropical.

  11. Fracture morphology and deformation characteristics of repeatedly impacted thermoplastic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Coban, Onur [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey)], E-mail: onur_coban@yahoo.com; Bora, Mustafa Ozguer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Sinmazcelik, Tamer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Tubitak-Mam, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey); Cuerguel, Ismail [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Guenay, Volkan [Tubitak-Mam, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey)

    2009-03-15

    Deformations of thermoplastic matrix composites during impact fatigue loading were investigated by instrumented impacts tester and scanning electron and optic microscopy (SEM). Curves of damage evolution against the number of repeated impacts to fracture the composites revealed three distinct zones: fibre micro buckling and shear fracture of fibres (1st region), initiation and propagation of delaminations and matrix deformations (2nd region), propagation of delaminations and fibre cracking and pull out especially in tensile area (3rd region). Intensive deformations observed primarily in compression region during impact-fatigue loading can be explained by lower compressive strength of composites compared to their tensile strength.

  12. Surface chemical composition of human maxillary first premolar as assessed by X-ray photoelectron spectroscopy (XPS)

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Leo [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada); Nelson, Alan E. [Department of Chemical and Materials Engineering, University of Alberta (Canada)], E-mail: aenelson@dow.com; Heo, Giseon [Department of Statistics, Department of Dentistry, University of Alberta (Canada); Major, Paul W. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada)

    2008-08-30

    The surface chemical composition of dental enamel has been postulated as a contributing factor in the variation of bond strength of brackets bonded to teeth, and hence, the probability of bracket failure during orthodontic treatment. This study systematically investigated the chemical composition of 98 bonding surfaces of human maxillary premolars using X-ray photoelectron spectroscopy (XPS) to ascertain compositional differences between right and left first premolars. The major elements detected in all samples were calcium, phosphorus, oxygen, nitrogen and carbon. Surface compositions were highly variable between samples and several elements were found to be highly correlated. No statistical significant difference in the chemical composition of the maxillary right and left first premolars was found (p > 0.05). Knowledge of the chemical composition of enamel surfaces will facilitate future studies that relate this information to the variations in dental enamel bond strength.

  13. The Influence and Impact of Textbooks on Chemical Education

    Science.gov (United States)

    Journal of Chemical Education, 1977

    1977-01-01

    Presents six papers that were presented at a one-day symposium dealing with the influence of textbooks on chemical education. Specific topics include textbooks in inorganic, organic, analytical, and physical chemistry, and the history of chemistry textbooks in the United States. (MLH)

  14. Numerical modeling of chemical spills and assessment of their environmental impacts

    Science.gov (United States)

    Chemical spills in surface water bodies often occur in modern societies, which cause significant impacts on water quality, eco-environment and drinking water safety. In this paper, chemical spill contamination in water resources was studied using a depth-integrated computational model, CCHE2D, for p...

  15. IMPACTS OF SMALL COLUMN ION EXCHANGE STREAMS ON DWPF GLASS FORMULATION: KT05- AND KT06-SERIES GLASS COMPOSITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Edwards, T.

    2011-01-03

    This report is the second in a series of studies of the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. The KT05-series glasses were selected, fabricated, and characterized to further study glass compositions where iron titanate crystals had been previously found to form. The intent was to better understand the mechanisms and compositions that favored the formation of crystals containing titanium. Formation of these crystalline phases was confirmed. Increased Na{sub 2}O concentrations had little if any impact on reducing the propensity for the formation of the iron titanate crystalline phases. Other physical properties of these glasses were not measured since the intent was to focus on crystallization. Additional studies are suggested to investigate the potential impacts of Al{sub 2}O{sub 3} and K{sub 2}O on crystallization in glasses with high TiO{sub 2} concentrations. The KT06-series glasses were selected, fabricated, and characterized to further study glass compositions that, while broader than the current projections for DWPF feeds with SCIX material, are potential candidates for future processing (i.e., the compositions are acceptable for processing by the Product Composition Control System (PCCS) with the exception of the current TiO{sub 2} concentration constraint). The chemical compositions of these glasses matched well with the target values. The chemical durabilities of all the glasses were acceptable relative to the Environmental Assessment (EA) benchmark. Minor crystallization was identified in some of the slowly cooled glasses, although this crystallization did not impact chemical durability. Several of the KT06-series compositions had durability values that, while acceptable, were not accurately predicted by the current durability models

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

    Directory of Open Access Journals (Sweden)

    Z. J. Wu

    2013-03-01

    Full Text Available 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, κ, 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 (κHTDMA and chemical composition-derived (κchem hygroscopicity parameters was performed based on the Zdanovskii–Stokes–Robinson (ZSR mixing rule. Using size-averaged chemical composition, the κ 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 κHTDMA and κchem 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, κorg is positively correlated with the O : C ratio (κorg =0.19 · (O : C−0.03. Such correlation is helpful to define the κorg value in the closure study. κ 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 κ 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 (κ

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

    Science.gov (United States)

    Miladinović, Dragoljub L; Ilić, Budimir S; Mihajilov-Krstev, Tatjana M; Nikolić, Nikola D; Miladinović, Ljiljana C; Cvetković, Olga G

    2012-05-01

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

  18. Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

    Directory of Open Access Journals (Sweden)

    Jaqueline Albano de Morais

    2016-01-01

    Full Text Available Abstract Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate, EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curauá fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

  19. Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

    Directory of Open Access Journals (Sweden)

    Jaqueline Albano de Morais

    Full Text Available Abstract Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate, EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curauá fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

  20. Diffusion in plasma: the Hall effect, compositional waves, and chemical spots

    CERN Document Server

    Urpin, Vadim

    2016-01-01

    We consider diffusion caused by a combined influence of the electric current and the Hall effect, and argue that such diffusion can form inhomogeneities of the chemical composition in plasma. The considered mechanism can be responsible for a formation of element spots in laboratory and astrophysical plasmas. This current-driven diffusion can be accompanied by propagation of a particular type waves in which the impurity number density oscillate alone. These compositional waves exist if the magnetic pressure in plasma is much greater than the gas pressure,

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

    Science.gov (United States)

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

    2014-11-01

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

  2. Chemical composition of volatile oils from leaves of Nectandra megapotamica Spreng. (Lauraceae)

    Energy Technology Data Exchange (ETDEWEB)

    Romoff, Paulete; Ferreira, Marcelo J.P., E-mail: romoff@mackenzie.b [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Centro de Ciencias e Humanidades; Padilla, Ricardo; Toyama, Daniela O.; Favero, Oriana A. [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Centro de Ciencias Biologicas e da Saude; Lago, Joao Henrique G. [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Dept. de Ciencias Exatas e da Terra

    2010-07-01

    The volatile oils from Nectandra megapotamica Spreng. leaves, collected in February and August of 2007 and at 7:00 and 12:00 h (samples A - D), were extracted by hydrodistillation and the chemical composition was analyzed by GC-FID and GC/MS. A total of nineteen compounds were identified with predominance of oxygenated sesquiterpenes, among them, a-bisabolol, was the main constituent (62.3-69.4 %). After chromatographic separation procedures, this compound was purified from crude oil and its structure was confirmed by analysis of NMR data. This paper describes for the first time the composition of the leaves volatile oil from N. megapotamica. (author)

  3. Processing–structure–property relations of chemically bonded phosphate ceramic composites

    Indian Academy of Sciences (India)

    H A Colorado; C Hiel; H T Hahn

    2011-07-01

    Mechanical properties and microstructures of a chemically bonded phosphate ceramic (CBPC) and its composite with 1.0 wt% graphite nanoplatelets (GNPs) reinforcement have been investigated. Microstructure was identified by using optical and scanning electron microscopes, X-ray tomography, and X-ray diffraction. In addition, weight loss of the resin at room temperature was studied. The microstructure characterization shows that CBPC is itself a composite with several crystalline (wollastonite and brushite) and amorphous phases. SEM and micro tomography show a homogeneous distribution of crystalline phases. Bending and compression strength of the CBPC was improved by reducing bubbles via preparation in vacuum.

  4. Is there a chemical interaction between calcium phosphates and organic compounds in the organic/inorganic composites?

    Energy Technology Data Exchange (ETDEWEB)

    Dorozhkin, S.V. [Research Inst. of Fertilisers, Moscow (Russian Federation)

    2001-07-01

    Solid composites of three biologically relevant calcium phosphates and hydroxypropylmethylcellulose (HPMC) were prepared at temperatures of 121 C. Properties of the composites obtained were studied by FTIR, X-ray diffraction, and SEM techniques. Special attention was devoted to seeking of a possible chemical interaction between the calcium phosphates and HPMC. No chemical interaction was found. Thus, HPMC was proven to have no influence on the chemical properties of calcium phosphates. (orig.)

  5. The chemical composition and fluxes of atmospheric wet deposition at four sites in South Africa

    Science.gov (United States)

    Conradie, E. H.; Van Zyl, P. G.; Pienaar, J. J.; Beukes, J. P.; Galy-Lacaux, C.; Venter, A. D.; Mkhatshwa, G. V.

    2016-12-01

    South Africa is the economic hub of southern Africa and is regarded as an important source region of atmospheric pollutants. A nitrogen dioxide (NO2) hotspot is clearly visible from space over the South African Mpumalanga Highveld, while South Africa is also regarded as the 9th largest anthropogenic sulphur (S) emitting country. Notwithstanding the importance of South Africa with regard to nitrogen (N) and S emissions, very limited data has been published on the chemical composition of wet deposition for this region. This paper presents the concentrations of sodium (Na+), ammonium (NH4+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), nitrate (NO3-), chloride (Cl-), sulphate (SO42-) and water-soluble organic acids (OA) in the wet deposition samples collected between 2009 and 2014 at four South African IDAF (IGAC DEBITS Africa) sites, which are regarded as regional representatives of the north-eastern interior. Also, wet deposition fluxes of the ten ions are calculated and presented in this paper. The results show that the total ionic concentrations and fluxes of wet deposition were much higher at the two sites closer to anthropogenic emissions, while the pH of wet deposition at these two sites were lower compared to that of the two sites that were less impacted by anthropogenic emissions. . The major sources of the ten ions included marine, terrigenous (crust), fossil fuel combustion, agriculture and biomass burning. Significant contributions from fossil fuel combustion were determined for the two sites in close proximity to anthropogenic source regions. The results of back trajectory analysis, however, did indicate that the two remote sites are also affected by air masses passing over the source region through anti-cyclonic recirculation. The largest contributions at the two sites distant from the anthropogenic source regions were marine sources, while the impact of biomass burning was also more significant at the remote sites. Comparison to previous wet

  6. Experimental impact testing and analysis of composite fan cases

    Science.gov (United States)

    Vander Klok, Andrew Joe

    ) diameter single stage gas gun was developed. A thermodynamic based relationship between the required gas pressure and targeted velocity was proposed. The predicted velocity was within +/-7%. Quantitative measurements of force and displacement were attempted. The transmitted impact force was measured with load cells. The out-of-plane deformation was measured with a projection grating profilometry method. The composite panels and fan cases used in this work were made of S2-glass plain weave fabrics with API SC-15 toughened epoxy resin using the vacuum assisted resin transfer molding (VARTM) method. Using the gas gun, the impact behavior of the composite was investigated at velocities ranging from 984ft/s to 1502ft/s (300m/s to 458m/s) following a draft ASTM testing standard. To compare the ballistic protection capability of different materials, a new parameter EBL, the projectile kinetic energy at the target ballistic limit normalized by the contact area of the projectile, was proposed. S2-glass/epoxy composite is ranked very high in EBL per areal weight. Finally, a testing method for replicating spin pit testing with a gas gun test was developed. Major differences between the two tests are the initial conditions of the blade upon contact with the target. In spin testing, the released blade has two velocity components, rotational and translational whereas in gas gun testing, the projectile has only the translational velocity. To account for the influence of the rotational velocity, three projectile designs were experimentally investigated. The results show that to generate similar damage modes in gas gun testing, it is critical to ensure the deformation of the projectile before testing is similar to that of a released blade. With the pre-bent blade, the gas gun experiment was able to replicate the damage modes of the fan case in FBO test on flat composite panels.

  7. Chemical Composition and Antimicrobial Activity of Echinophora spinosa L. (Apiaceae Essential Oil

    Directory of Open Access Journals (Sweden)

    Jasmina M. Glamočlija

    2011-01-01

    Full Text Available The present study was undertaken to investigate the chemical composition and effectiveness of the essential oil isolated from Echinophora spinosa on different bacterial and fungal species. Chemical analysis (GC/MS showed that δ³-carene (60,86 %, α-phellandrene (7,12%, p-cymene (6,22 %, myrcene (4,82 % and β-phellandrene (2,73 % were dominant components in this oil. Essential oil tested showed good antimicrobial activity. Antimicrobial potential of this oil was higher than potential of commercial antimicrobial drugs tested, streptomycin, bifonozole and ketoconazole.

  8. Planet signatures in the chemical composition of Sun-like stars

    CERN Document Server

    Melendez, Jorge

    2016-01-01

    There are two possible mechanisms to imprint planet signatures in the chemical composition of Sun-like stars: i) dust condensation at the early stages of planet formation, causing a depletion of refractory elements in the gas accreted by the star in the late stages of its formation; ii) planet engulfment, enriching the host star in lithium and refractory elements. We discuss both planet signatures, the influence of galactic chemical evolution, and the importance of binaries composed of stellar twins as laboratories to verify abundance anomalies imprinted by planets.

  9. Simulation of Gas Detonation Propagation in a Medium Having Variable Chemical Composition

    Science.gov (United States)

    Prokhorov, E. S.

    2017-01-01

    Within the framework of a quasi-one-dimensional approximation, a mathematical model of the propagation of a detonation wave in a tube filled with explosive gas mixture with spatially variable chemical composition has been formulated, and the respective problem has been solved numerically. The shift in the chemical equilibrium of detonation products as well as the friction and heat removal losses were taken into account. The proposed mathematical model allows one to describe steady-state (of Chapman-Jouguet) and over-compressed detonation regimes.

  10. Morphology tailoring of nano/micro-structured conductive polymers, composites and their applications in chemical sensors.

    Science.gov (United States)

    Ma, Xingfa; Gao, Mingjun; He, Xiaochun; Li, Guang

    2010-11-01

    Conductive polymer is one of the important multi-functional materials. It has many applications in light-emitting diodes, chemical sensors, biosensors, et al. This paper provides a relatively comprehensive review on the progress of conductive polymer and composite as sensitive film for sensors to chemical vapors including patents, papers and our preliminary research results. Especially, the feature of conjugated polymers, the processing technology, doping characteristics and some factors affecting gas responses are discussed. Otherwise, the developments of nanostructured conductive polymer and organic-inorganic hybrid film sensor with high sensitivity and rapid response to vapors are also described, and some suggestions are proposed.

  11. Chemical Composition and Dynamics of the Upper Troposphere and the Lower Stratosphere: Overview of the Project

    Science.gov (United States)

    Sofieva, V. F.; Liu, C.; Huang, F.; Kyrola, E.; Liu, Y.; Ialongo, I.; Hakkarainen, J.; Zhang, Y.

    2016-08-01

    The DRAGON-3 cooperation study on the upper troposphere and the lower stratosphere (UTLS) is based on new satellite data and modern atmospheric models. The objectives of the project are: (i) assessment of satellite data on chemical composition in UTLS, (ii) dynamical and chemical structures of the UTLS and its variability, (iii) multi-scale variability of stratospheric ozone, (iv) climatology of the stratospheric aerosol layer and its variability, and (v) updated ozone climatology and its relation to tropopause/multiple tropopauses.In this paper, we present the main results of the project.

  12. Low Velocity Impact Response Analysis of Shape Memory Alloy Reinforced Composite Beam

    Institute of Scientific and Technical Information of China (English)

    WU Yongdong; ZHONG Weifang; WU Guorong; ZOU Jing

    2005-01-01

    The low velocity impact responses of shape memory alloy ( SMA ) reinforced composite beams were analyzed by employing the finite element method. The finite element dynamic equation was solved by the Newmark direct integration method, the impact contact force was determined using the Hertzian contact law, and the influence of SMA fibers on stiffness matrix is studied. Numerical results show that the SMA fibers can effectively improve the low velocity impact response property of composite beam.

  13. Comparison of toxicological impacts of integrated and chemical pest management in Mediterranean greenhouses

    NARCIS (Netherlands)

    Anton, A.; Castells, F.; Montero, J.I.; Huijbregts, M.A.J.

    2004-01-01

    The goal of this paper is to assess the relative impacts of pest-control methods in greenhouses, based on current LCA tools. As a case study, the relative impacts of two tomato production methods, chemical pest management (CPM) and integrated pest management (IPM), are assessed. The amount of the ac

  14. EFFECTS OF CHEMICAL FOAMING AGENTS ON THE PHYSICO-MECHANICAL PROPERTIES AND RHEOLOGICAL BEHAVIOR OF BAMBOO POWDER-POLYPROPYLENE FOAMED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Xiaxing Zhou,

    2012-02-01

    Full Text Available To make full use of bamboo resources in China and explore the foaming mechanism of bamboo powder-polypropylene (PP foamed composites, a foamed composite of 54 wt% PP and 13 wt% HMSPP containing 33 wt% bamboo powder blends was prepared by injection moulding. Effects of chemical foaming agents (CFA on the mechanical properties and rheological behavior of foamed composites were investigated. The mechanical measurements and ESEM test results indicated that the composite with 1% modified exothermic FA had smaller cell size and better cell distribution compared with endothermic FA. It also had better physico-mechanical properties, with a decrease of 14.2% in density and an increase of 16.8% to 40.2% in the specific tensile, bending, and notched impact strength compared with the non-foamed composite. The frequency sweep results indicated that all composites had a shear- thinning behavior, and both the modulus and complex viscosity of composite with 1% exothermic FA decreased compared with those of the non-foamed composite. The shear rate scans revealed that the non-Newtonian fluid index increased with the increase of exothermic FA content. The viscous activation energy of the modified composite with 1% exothermic FA was 46.41KJ•mol-1. This was an increase of 8.9% compared with that of the non-foamed analogue.

  15. The impact of environmental chemicals on wildlife vertebrates.

    Science.gov (United States)

    Bernanke, Julia; Köhler, Heinz-R

    2009-01-01

    A plethora of papers have been published that address the affects of chemicals on wildlife vertebrates. Collectively, they support a connection between environmental pollution and effects on wildlife vertebrate populations; however, causal relationships between exposure, and reproduction or population structure effects have been established for only a few species. In a vast number of fish species, particularly in teleosts, it is accepted that EDCs affect the endocrine system of individuals and may alter sexual development and fertility. However, only few studies have demonstrated population-level consequences as a result of exposure to EDCs. The same applies to fish populations exposed to contaminants or contaminant mixtures with non-endocrine modes of action; few studies link EDCs directly to population affects. Amphibian populations are declining in many parts of the world. Although environmental chemicals have been shown to affect reproduction and development in single organism tests, the degree to which chemicals contribute to the decline of amphibians, either alone, or in concert with other factors (habitat loss, climate change, introduction of neozoa, UV-B irradiation, and direct exploitation) is still uncertain. Because reptilian endocrinology is so variable among species, EDC effects reported for individual species cannot easily be extrapolated to others. Nevertheless, for some species and locations (e.g., the Lake Popka alligators), there is considerable evidence that population declines are caused or triggered by chemical pollution. In birds, there is ample evidence for EDC effects on the reproductive system. In some bird species, effects can be linked to population declines (e.g., based on egg-shell thinning induced by DDT/DDE). In contrast, other bird species were shown to be rather insensitive to endocrine disruption. Oil spills, which also may exert endocrine effects, are usually regarded to cause only transient bird population effects, although long

  16. A Chemical Model of Micrometeorite Impact into Olivine

    Science.gov (United States)

    Sheffer, A. A.; Melosh, H. J.

    2005-01-01

    Laboratory simulations of space weathering using laser irradiation have been successful in reproducing space weathering characteristics such as the reduction of olivine to form nanophase iron particles. However, the chemistry of the reduction of Fe2+ in olivine to Fe metal has not been fully explored. We present a thermodynamic model of olivine undergoing post-impact cooling and decompression.

  17. Microfluidic encapsulation for self-healing material and investigation of its impacts on composite performance

    Science.gov (United States)

    Lemmens, Ryan J.

    Encapsulation is a key enabling technology of self-healing materials for which incorporation of reactive materials into a composite, without loss of functionality, is required for damage repair. The functionalized particles resulting from such processes must be readily incorporable into a composite and have minimal detrimental impact on its undamaged properties. At the same time, their morphology must preferentially promote the release of their content during a damage event. However, there is still a need for new techniques capable of fine tuning particle properties for the controlled design of composite performance. To introduce superior processing control, two microfluidics based encapsulation processes have been developed, one each for the individual components of a two-part chemical healing system, namely dicyclopentadiene and Grubb's catalyst. These processes have enabled significantly enhanced performance of self-healing epoxy composites by introducing unprecedented control over particle morphology. The microfluidics based encapsulation platform is first demonstrated by emulsification, using droplet microfluidics, and subsequent encapsulation of dicyclopentadiene. The reported approach allows for facile control of mean microcapsule diameter thru variation of fluid flow rates. The microcapsules exhibit coefficients of variation (CV) of diameter in the range 1-3 (i.e. monodisperse is typically defined as CV smaller than 5), an order of magnitude reduction when compared with conventional batch emulsification methods whose typical CV is 20-40. This control over microcapsule uniformity has led to significant improvement in self-healing composite performance as exemplified by ˜25% higher undamaged fracture toughness. A microfluidic solution spinning process is then developed to encapsulate Grubb's catalyst, the most expensive component of this particular material system, in a novel fibrous morphology. The continuous, on-chip fiber production allows for

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

    Science.gov (United States)

    Raju, K.; Rakkappan, C.

    2008-11-01

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

  19. Broadening Our Portfolio in the Genetic Improvement of Maize Chemical Composition.

    Science.gov (United States)

    Wen, Weiwei; Brotman, Yariv; Willmitzer, Lothar; Yan, Jianbing; Fernie, Alisdair R

    2016-08-01

    The adoption of recombinant inbred line and introgression line populations, as well as the study of association mapping panels, has greatly accelerated our ability to identify the genes underlying plant phenotypic variance. In tandem, the development of metabolomics approaches has greatly enhanced our ability to comprehensively define cellular chemical composition. As a consequence, breeding for chemical composition is being extended beyond our traditional targets of oil and protein to include components such as essential amino acids, vitamins, and antioxidant secondary metabolites with considerable purported consequences for human health. Here, we review the above-mentioned developments paying particular attention to the genetic architecture of metabolic traits as well as updating the perspective for utilizing metabolomics in maize improvement.

  20. Effect of Crossbreed on the Muscle Quality (Chemical Composition) in Yun-Ling Black Goats

    Institute of Scientific and Technical Information of China (English)

    JIA Jun-jing; TIAN Yun-bo; ZHANG Xi; HUANG Qi-chao; WEN Sheng-ping; GU Feng-ying; GE Chang-rong; CAO Zhen-hui; CHENG Zhi-bin; M. Jois

    2009-01-01

    Twenty castrated male goats, each of Yun-Ling Black goats (YLB goat), N×YLB hybrid goats (Nubian ♂×Yun-Ling Black goats ♀) and B×YLB hybrid goats (Boer ♂×Yun-Ling Black goats ♀), were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi (LD) and biceps femoris (BF) muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content (P0.05). The YLB goats had significantly higher (P0.05). In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower (P<0.05) than that in the hybrid goats.

  1. Chemical composition and antimicrobial activity of the essential oils of Pinus pinaster

    Directory of Open Access Journals (Sweden)

    Nouara Ait Mimoune

    2013-08-01

    Full Text Available Objective: To investigate the antimicrobial activity and chemical composition of essential oils of Pinus pinaster. Methods: Essential oils were extracted from the needles by hydrodistillation. The chemical composition of the obtained essential oils was analyzed using GC-MS technique. The antimicrobial potential has been tested against six microorganisms performing the disc diffusion assay. Results: Twenty-three components have been identified. β-caryophyllene (30.9% and β-selinene (13.45% were predominant compounds. The essential oil exhibited a moderate activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli, but did not affect the growth of Erwinia amylovora. Aspergillus flavus and Aspergillus niger were not inhibited by maritime pine essential oils. Conclusions: The essential oils from Pinus pinaster can be used as an antibacterial agent.

  2. Anionic markers for the forensic identification of Chemical Ignition Molotov Cocktail composition.

    Science.gov (United States)

    Martín-Alberca, C; Ferrando, J L; García-Ruiz, C

    2013-03-01

    An improved version of the famous Molotov cocktail is the Chemical Ignition Molotov Cocktail (CIMC). This incendiary device contains chemical reagents that enable its self-ignition. The analysis of anions from CIMC residues by capillary electrophoresis (CE) allows the identification of the reagents used to produce the device, and provides forensic analysts with valuable information. Although, sulfate, chlorate, chloride, and perchlorate anions have been recently proposed in the literature as target anions to determine the CIMC composition, the identification of some of them could be controversial due to their presence in the environment. Therefore, the purpose of this study was to identify highly reliable anions capable of indicating the components used to prepare these self-initiated devices. The relationship among the detected anions in CIMC residues and the reagents employed in their elaboration is discussed. Some anions have been proposed as anionic markers of CIMC as incendiary devices. Additionally, the viability of different CIMC compositions was studied.

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

    Science.gov (United States)

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

    2015-01-01

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

  4. Surge-Resistant Nanocomposite Enameled Wire Using Silica Nanoparticles with Binary Chemical Compositions on the Surface

    Directory of Open Access Journals (Sweden)

    Jeseung Yoo

    2015-01-01

    Full Text Available We developed polyesterimide (PEI nanocomposite enameled wires using surface-modified silica nanoparticles with binary chemical compositions on the surface. The modification was done using silanes assisted by ultrasound, which facilitated high density modification. Two different trimethoxysilanes were chosen for the modification on the basis of resemblance of chemical compositions on the silica surface to PEI varnish. The surface-modified silica was well dispersed in PEI varnish, which was confirmed by optical observation and viscosity measurement. The glass transition temperature of the silica-PEI nanocomposite increased with the silica content. The silica-dispersed PEI varnish was then used for enameled wire fabrication. The silica-PEI nanocomposite enameled wire exhibited a much longer lifetime compared to that of neat PEI enameled wire in partial discharge conditions.

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

    Science.gov (United States)

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

    2013-02-01

    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.

  6. Evaluation of the Chemical Composition of Brazilian Commercial Cymbopogon citratus (D.C. Stapf Samples

    Directory of Open Access Journals (Sweden)

    Evandro de Castro Melo

    2008-08-01

    Full Text Available Abstract: The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves, seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68% the essential oil content, as well as the percentage of myrcene in the oils.

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

    Science.gov (United States)

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

    2012-07-01

    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.

  8. Effect of enzyme addition to forage at ensiling on silage chemical composition and NDF degradation characteristics

    DEFF Research Database (Denmark)

    Dehghani, Mohammad Reza; Weisbjerg, Martin Riis; Hvelplund, Torben

    2012-01-01

    The effect of different exogenous fibrolytic enzymes added to forages at ensiling was examined for effect on chemical composition and in vitro NDF degradability characteristics of the resulting silage. Maize stover and lucerne were used to study effect on chemical composition in experiment 1...... digestibility decreased in treated maize stover silage. Potential NDF degradability decreased due to enzyme treatments but not for all maize stover treatments. Treatments with combination of enzymes with glucanase, β-glucanase and pectinase activity mostly resulted in increases in fermentation products compared......, and two varieties of maize stover, lucerne and grass clover were used to study NDF degradation characteristics in experiment 2. Forages were treated with enzymes (500 mg crude protein of the enzyme products/kg DM) and ensiled for 60 days in vacuum-sealed bags. Samples of forage (before ensiling...

  9. Qualitative and quantitative studies of chemical composition of sandarac resin by GC-MS.

    Science.gov (United States)

    Kononenko, I; de Viguerie, L; Rochut, S; Walter, Ph

    2017-01-01

    The chemical composition of sandarac resin was investigated qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS). Six compounds with labdane and pimarane skeletons were identified in the resin. The obtained mass spectra were interpreted and the mass spectrometric behaviour of these diterpenoids under EI conditions was described. Quantitative analysis by the method of internal standard revealed that identified diterpenoids represent only 10-30% of the analysed sample. The sandarac resin from different suppliers was analysed (from Kremer, Okhra, Color Rare, La Marchande de Couleurs, L'Atelier Montessori, Hevea). The analysis of different lumps of resins showed that the chemical composition differs from one lump to another, varying mainly in the relative distributions of the components.

  10. Chemical composition and in vitro antioxidative potential of essential oil isolated from Curcuma longa L. leaves

    Institute of Scientific and Technical Information of China (English)

    R. Priya; A. Prathapan; K.G Raghu; A. Nirmala Menon

    2012-01-01

    Objective: To determine the chemical composition and antioxidant potential of essential oil isolated from the leaves of Curcuma longa (turmeric). Methods: Chemical composition of the oil was analyzed using GC-MS. Antiperoxidative potential was evaluated using linoliec acid emulsion system. Free radical scavenging activity was evaluated using stable DPPH and ABTS free radicals. Results: GC-MS analyses showed that major compound present in the turmeric leaf oil is b-sesquiphellandrene (22.8%) followed by terpinolene (9.5%). Essential oil also exhibited reductive potential and antioxidant potential in linoleic acid emulsion system along with DPPH and ABTS free radical scavenging potential. Conclusions: The overall result suggests that turmeric leaf oil is capable of retarding oxidation reaction and free radical mediated damage and can be developed as a potent natural antioxidant.

  11. Chemical Composition and Fatty Acids of Glodok Fish by High Thermal Processing

    Directory of Open Access Journals (Sweden)

    Sri Purwaningsih

    2014-11-01

    Full Text Available Glodok is an economically underrated fish with a high nutrient content. The research aims to study the changes on chemical composition, fatty acids, omega-6 and omega-3 ratio in glodok muscle after processing with different methods of boiling, steaming, and boiling with addition of salt (3%. The results showed that the treatment (boiling, steaming, and boiling with addition of salt gives a significant effect (α=0.05 in water content, ash, lipid content, nervonat acid, linoleic acid, arachidonic acid, EPA, and DHA. The best processing method was steaming. The ratio of omega-3 and omega-6 in fresh glodok fish was 2,1:1, which is higher than WHO recommendation of 0,6:1,7.Keywords: chemical composition, fatty acid, glodok fish, processing

  12. Chemical Composition and Antibacterial Activity of Essential Oils of Two Species of Lamiaceae against Phytopathogenic Bacteria.

    Science.gov (United States)

    Gormez, Arzu; Bozari, Sedat; Yanmis, Derya; Gulluce, Medine; Sahin, Fikrettin; Agar, Guleray

    2015-01-01

    In this study, we aimed to determine chemical composition and antibacterial activities of Satureja hortensis and Calamintha nepeta against to 20 phytopathogenic bacteria causing serious crop loss. The essential oils of S. hortensis and C. nepeta were isolated by the hydrodistillation method and the chemical composition of the essential oils were analyzed by GC-MS. The antibacterial properties of the essential oils were evaluated against 20 phytopathogenic bacteria through Disc diffusion assay and micro dilution assay. The results revealed that the essential oils of S. hortensis and C. nepeta have significant antibacterial activity. Furthermore, the findings of the study are valuable for future investigations focusing on the alternative natural compounds to control plant diseases.

  13. Chemical composition and antimicrobial activity of the essential oils of Pinus pinaster

    Institute of Scientific and Technical Information of China (English)

    Nouara Ait Mimoune; Djouher Ait Mimoune; Aziza Yataghene

    2013-01-01

    Objective: To investigate the antimicrobial activity and chemical composition of essential oils ofPinus pinaster. Methods: Essential oils were extracted from the needles by hydrodistillation. The chemical composition of the obtained essential oils was analyzed using GC-MS technique. The antimicrobial potential has been tested against six microorganisms performing the disc diffusion assay.Results:Twenty-three components have been identified. β-caryophyllene (30.9%) and β-selinene (13.45%) were predominant compounds. The essential oil exhibited a moderate activity againstStaphylococcus aureus, Bacillus subtilis and Escherichia coli, but did not affect the growth of Erwinia amylovora. Aspergillus flavus and Aspergillus niger were not inhibited by maritime pine essential oils.Conclusions:The essential oils from Pinus pinaster can be used as an antibacterial agent.

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

    Science.gov (United States)

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

    2015-02-01

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

  15. Chemically Modified Ordered Mesoporous Carbon/Polyaniline Composites for Electrochemical Capacitors

    Institute of Scientific and Technical Information of China (English)

    KONG Ling-bin; ZHANG Jing; CAI Jian-jun; YANG Zhen-sheng; LUO Yong-chun; KANG Long

    2011-01-01

    Chemically modified ordered mesoporous carbon CMK-3 materials were prepared by means of an easy wet-oxidative method in 2 mol/L nitric acid aqueous solution. A large amount of oxygen-containing functional groups were introduced onto the CMK-3 surface. Modified CMK-3(m-CMK-3) and aniline monomer were polymerized via an in situ chemical oxidative polymerization method. Morphological characterizations of m-CMK-3/PANI (polyaniline) composites were carried out via field emission scanning electron microscopy(SEM). Their electrochemical properties were investigated with cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The m-CMK-3/PANI composites have excellent properties in capacitance, and the highest specific capacitance(SC) value was up to 489 F/g, suggesting their potential application in the electrode material for electrochemical capacitors.

  16. Combined use of meio- and macrobenthic indices to assess complex chemical impacts on a stream ecosystem

    Science.gov (United States)

    McKnight, Ursula S.; Sonne, Anne T.; Rasmussen, Jes J.; Traunspurger, Walter; Höss, Sebastian; Bjerg, Poul L.

    2016-04-01

    habitats for overall ecosystem health, many biological indices tend only to reflect the ecological quality of surface water, rather than of the sedimentary zones where the accumulation of pollutants is often highest. To address this issue, we monitored meiobenthic (i.e. nematodes) and macrobenthic invertebrate communities along a pollution gradient in order to assess the impact of multiple stressors on a groundwater-fed stream, and thus quantify the link between chemical and ecological status. The studied stressors included point source pollutants originating from contaminated groundwater and aquaculture, and diffuse source pollutants originating from conventional agriculture and urban areas. The use of macrofauna is now well-accepted for assessing ecological integrity in aquatic ecosystems, but less is known about the application of meiofaunal community indicators. High abundance and ubiquitous distribution are two potential advantages for including meiofaunal indicators, and notably - for the case of groundwater-surface water interactions - they are particularly suitable for identifying changes in environmental conditions over smaller spatial scales. The results indicate a change in community composition for both meio- and macrobenthic fauna, pointing towards the presence of a local impact resulting from the discharging contaminated groundwater, which extends downstream along a dilution gradient of the groundwater contaminants. Ecological impacts could be linked to xenobiotic compounds coming from groundwater (both chlorinated solvents and pharmaceuticals), as well as the presence of trace metals of diffuse and/or biogenic origin.

  17. Role of primary substrate composition and concentration on attenuation of trace organic chemicals in managed aquifer recharge systems

    KAUST Repository

    Alidina, Mazahirali

    2014-11-01

    This study was undertaken to investigate the role of primary substrate composition and concentration on the attenuation of biodegradable emerging trace organic chemicals (TOrCs) in simulated managed aquifer recharge (MAR) systems. Four sets of soil columns were established in the laboratory, each receiving synthetic feed solutions comprising different ratios and concentrations of peptone-yeast and humic acid as the primary substrate to investigate the effect on removal of six TOrCs (atenolol, caffeine, diclofenac, gemfibrozil, primidone, and trimethoprim). Based on abiotic control experiments, adsorption was not identified as a significant attenuation mechanism for primidone, gemfibrozil and diclofenac. Caffeine, atenolol and trimethoprim displayed initial adsorptive losses, however, adsorption coefficients derived from batch tests confirmed that adsorption was limited and in the long-term experiment, biodegradation was the dominant attenuation process. Within a travel time of 16h, caffeine - an easily degradable compound exhibited removal exceeding 75% regardless of composition or concentration of the primary substrate. Primidone - a poorly degradable compound, showed no removal in any column regardless of the nature of the primary substrate. The composition and concentration of the primary substrate, however, had an effect on attenuation of moderately degradable TOrCs, such as atenolol, gemfibrozil and diclofenac, with the primary substrate composition seeming to have a larger impact on TOrC attenuation than its concentration. When the primary substrate consisted mainly of refractory substrate (humic acid), higher removal of the moderately degradable TOrCs was observed. The microbial communities in the columns receiving more refractory carbon, were noted to be more diverse and hence likely able to express a wider range of enzymes, which were more suitable for TOrC transformation. The effect of the primary substrate on microbial community composition, diversity

  18. Quantifying impacts of coupled chemical and physical heterogeneity on water quality evolution during Aquifer Storage and Recovery

    Science.gov (United States)

    Deng, H.; Descourvieres, C.; Seibert, S.; Harris, B.; Atteia, O.; Siade, A. J.; Prommer, H.

    2014-12-01

    Aquifer storage and recovery (ASR) is an important water management option in water-scarce regions. During wet periods surplus water is injected into suitable aquifers for storage and later recovery. ASR sites are, however, also ideal natural laboratories that provide opportunities for studying coupled physical and geochemical processes and water quality evolution at field-scale under well-controlled hydrological conditions. In this study, we use reactive transport modelling to assess the impacts of physical and chemical heterogeneities on the water quality evolution during the injection of oxic surface water into the anoxic, pyrite-bearing Leederville aquifer in Perth, Western Australia. Physical heterogeneity was identified from geophysical well logs and time lapse temperature logs. Those data were used to define the spatial, depth-varying alternation of three lithofacies (sandstone, siltstone and clay). Chemical heterogeneity was incorporated through distinct chemical zones, based on data derived from a comprehensive pre-trial geochemical characterization and from dedicated laboratory respirometer experiments. Calibration of flow and conservative transport parameters was constrained by the spatially varying measured chloride breakthrough behavior. Subsequent reactive transport modeling discerned the key geochemical processes that affected the water quality evolution during ASR. Clearly identified processes included oxidation of pyrite, mineralization of sedimentary organic carbon, ion exchange, dissolution of calcite and precipitation of ferrihydrite and siderite. We use the calibrated model to analyze the individual and the combined effects of the physical and chemical heterogeneities on the chemical composition of the recovered water during ASR.

  19. Behaviour of -glass fibre reinforced vinylester resin composites under impact fatigue

    Indian Academy of Sciences (India)

    Rita Roy; B K Sarkar; N R Bose

    2001-04-01

    An impact fatigue study has been made for the first time on 63.5% glass fibre reinforced vinylester resin notched composites. The study was conducted in a pendulum type repeated impact apparatus especially designed and fabricated for determining single and repeated impact strengths. A well-defined impact fatigue (S–N) behaviour, having a progressive endurance below the threshold single cycle impact fracture stress with decreasing applied stress has been demonstrated. Fractographic analysis revealed fracture by primary debonding having fibre breakage and pullout at the tensile zone, but a shear fracture of fibre bundles at the compressive zone of the specimen. The residual strength, modulus and toughness showed retention of the properties at high impact stress levels up to 1000 impacts followed by a sharp drop. Cumulative residual stresses with each number of impacts not withstanding the static fatigue failure at long endurances have been ascribed for the composite failures under the repeated impact stresses.

  20. Assessment of chemical emissions in life cycle impact assessment - focus on low substance data availability and

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred

    2004-01-01

    chemical groups, high data availability combined with low data demand, data useable in characterisation, user friendliness and transparency. A mainly qualitative evaluation of the existing selection methods against these performance criteria shows that none of these score high on all criteria...... be significantly dependent on the inclusion of toxicity- or chemical-related impact categories. The two main reasons for poor coverage of potential toxic impacts from chemical emissions in LCA studies are lack of available data on upstream emissions (e.g. emissions during production of raw materials) and lack...... of substance data on known emissions. To be able to characterize the potential toxic impacts on humans and the environment of chemical emissions, substance data on fate and effect are needed. The second goal of this thesis is to investigate how to deal with low substance data availability on especially effect...

  1. Incorporating Health Impacts from Exposure to Chemicals in Food Packaging in LCA

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Trier, Xenia; Jolliet, Oliver

    2014-01-01

    Life cycle assessments (LCA) on the environmental and public health impacts of food and beverage packaging materials have found some advantages to plastic over glass. Entirely missing from these evaluations are the health impacts of possible chemical, e.g. endocrine dis-ruptor, exposure through...... within the CPCAT database related to food-contact materials; out of these 107 are potential endocrine disruptors according to the TEDX list of endocrine disruptors. We also build a framework in an effort to begin harmonizing LCA to include health impacts of chemical exposure related to food packaging...

  2. Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets

    OpenAIRE

    2016-01-01

    Euterpe oleracea (açaí) is a palm tree well known for the high antioxidant activity of its berries used as dietary supplements. Little is known about the biological activity and the composition of its vegetative organs. The objective of this study was to investigate the antioxidant activity of root and leaflet extracts of Euterpe oleracea (E. oleracea) and characterize their phytochemicals. E. oleracea roots and leaflets extracts were screened in different chemical antioxidant assays (DPPH—2,...

  3. A Study on Chemical Compositions and Fiber Characteristics of Two Sympodial Bamboos

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The chemical composition and fiber characteristics of two sympodial bamboos have been studied in this paper. Based on analysis results, it is shown that the Whangee (D. Membranaceus Munro) bamboo is better than Yunnanicus bamboo(D. yunnaicus Hsueh et D. Z. Li) in utilization because of its higher specific gravity, better fiber length and its distribution rule and higher wall/lumen ratio, and that the Whangee bamboo is more suitable for papermaking and panel processing used in house construction. In addi...

  4. Chemical composition and antibacterial activity of essential oil of Pulicaria odora L.

    Science.gov (United States)

    Hanbali, Fadwa E L; Akssira, Mohamed; Ezoubeiri, Aicha; Gadhi, Chems Eddoha A; Mellouki, Fouad; Benherraf, Ahmed; Blazquez, Amparo M; Boira, Herminio

    2005-07-14

    The chemical composition of the volatile oil constituent from Pulicaria odora L. roots has been analyzed by GC/MS. Twenty-seven components were identified, being thymol (47.83%) and its derivative isobutyrate (30.05%) the main constituents in the oil. Furthermore, the oil was tested against seven bacteria at different concentrations. Results showed that the oil exhibited a significant antibacterial activity.

  5. Chemical Composition and Biological Activities of Fragrant Mexican Copal (Bursera spp.).

    Science.gov (United States)

    Gigliarelli, Giulia; Becerra, Judith X; Curini, Massimo; Marcotullio, Maria Carla

    2015-12-12

    Copal is the Spanish word used to describe aromatic resins from several genera of plants. Mexican copal derives from several Bursera spp., Protium copal, some Pinus spp. (e.g., P. pseudostrobus) and a few Fabaceae spp. It has been used for centuries as incense for religious ceremonies, as a food preservative, and as a treatment for several illnesses. The aim of this review is to analyze the chemical composition and biological activity of commercial Mexican Bursera copal.

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

    Science.gov (United States)

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

    2012-07-01

    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.

  7. Progress of Chemical Composition and Pharmacological Effects of Meretrix meretrix Linnaeus

    Institute of Scientific and Technical Information of China (English)

    Du; Zhengcai; Hou; Xiaotao; Huang; Qing; Deng; Jiagang; Fanshi; Fangcao

    2014-01-01

    Meretrix meretrix Linnaeus is a traditional marine drug. There are more than two thousand years of history using clamshell as a component of medicine.After a review of relevant literature at home and abroad for nearly 20 years,the author summarized chemical composition and pharmacological effects of M. meretrix,in order to provide a scientific basis for further development and utilization of M. meretrix.

  8. Chemical Composition and Biological Activities of Fragrant Mexican Copal (Bursera spp.

    Directory of Open Access Journals (Sweden)

    Giulia Gigliarelli

    2015-12-01

    Full Text Available Copal is the Spanish word used to describe aromatic resins from several genera of plants. Mexican copal derives from several Bursera spp., Protium copal, some Pinus spp. (e.g., P. pseudostrobus and a few Fabaceae spp. It has been used for centuries as incense for religious ceremonies, as a food preservative, and as a treatment for several illnesses. The aim of this review is to analyze the chemical composition and biological activity of commercial Mexican Bursera copal.

  9. Biomass production, yield and chemical composition of peppermint essential oil using different organic fertilizer sources

    OpenAIRE

    Costa, Andressa Giovannini; Bertolucci,Suzan Kelly Vilela; Chagas,Jorge Henrique; Ferraz, Elza de Oliveira [UNESP; Pinto,José Eduardo Brasil Pereira

    2013-01-01

    Mentha x piperita L. is an aromatic and medicinal species belonging to the family Lamiaceae that is popularly known as peppermint. The aim of this study was to evaluate the effects of organic fertilizer sources on the biomass production, yield and chemical composition of peppermint (Mentha piperita L.) essential oil. The experiment was conducted using a completely randomized design (CRD) with a 2 x 5 factorial scheme, two sources of manure (cattle and poultry), five doses (0, 3, 6, 9 and 12 k...

  10. The Chemical Compositions of Thermal Waters at Ciarinem and Cilayu, Pameungpeuk, West Java - Indonesia

    Directory of Open Access Journals (Sweden)

    N.R. Herdianita

    2008-03-01

    Full Text Available Thermal waters at Ciarinem and Cilayu, Pameungpeuk, West Java, Indonesia have different characteristics: Ciarinem water is a steam heated sulfate type and occurs as hot springs, whereas Cilayu water discharges as hot pools and is a chloride water type. Their chemical compositions indicate that the thermal waters are outflows of a volcanic–magmatic associated geothermal system. The solute geothermometers calculate that the subsurface reservoir temperatures range from 150o to 200ºC.

  11. Chemical composition, antimicrobial, antioxidant and cytotoxic activity of Rosa centifolia L. essential oil

    OpenAIRE

    Nikolić, Miloš; Isabel C. F. R. Ferreira; Calhelha, Ricardo C.; Ângela FERNANDES; Marković, Dejan; Marković, Tatjana; Ćirić, Ana; Glamočlija, Jasmina; Soković, Marina

    2013-01-01

    The genus Rosa comprises more than 200 species appreciated for their use in perfume and cosmetic industry. The aim of this study was to investigate chemical composition, antimicrobial, antioxidant and cytotoxic activities of Rosa centifolia L. essential oil, in an attempt to contribute to the use of this plant as alternative product for microbial control and cancer therapy. The results of GC/MS analysis showed the presence of 12 components. The major constituents were: phenyl ethyl alcohol (5...

  12. Concentration of mycotoxins and chemical composition of corn silage: a farm survey using infrared thermography.

    Science.gov (United States)

    Schmidt, P; Novinski, C O; Junges, D; Almeida, R; de Souza, C M

    2015-09-01

    This work evaluated the chemical composition and mycotoxin incidence in corn silage from 5 Brazilian dairy-producing regions: Castro, in central-eastern Paraná State (n=32); Toledo, in southwestern Paraná (n=20); southeastern Goiás (n=14); southern Minas Gerais (n=23); and western Santa Catarina (n=20). On each dairy farm, an infrared thermography camera was used to identify 3 sampling sites that exhibited the highest temperature, a moderate temperature, and the lowest temperature on the silo face, and 1 sample was collected from each site. The chemical composition and concentrations of mycotoxins were evaluated, including the levels of aflatoxins B1, B2, G1, and G2; zearalenone; ochratoxin A; deoxynivalenol; and fumonisins B1 and B2. The corn silage showed a highly variable chemical composition, containing, on average, 7.1±1.1%, 52.5±5.4%, and 65.2±3.6% crude protein, neutral detergent fiber, and total digestible nutrients, respectively. Mycotoxins were found in more than 91% of the samples, with zearalenone being the most prevalent (72.8%). All samples from the Castro region contained zearalenone at a high average concentration (334±374µg/kg), even in well-preserved silage. The incidence of aflatoxin B1 was low (0.92%). Silage temperature and the presence of mycotoxins were not correlated; similarly, differences were not observed in the concentration or incidence of mycotoxins across silage locations with different temperatures. Infrared thermography is an accurate tool for identifying heat sites, but temperature cannot be used to predict the chemical composition or the incidence of mycotoxins that have been analyzed, within the silage. The pre-harvest phase of the ensiling process is most likely the main source of mycotoxins in silage.

  13. Chemical composition analysis of raw materials used in iron ore sinter plants in Poland

    Directory of Open Access Journals (Sweden)

    D. Burchart-Korol

    2014-07-01

    Full Text Available The main goal of the study was the analysis of the chemical compositions of raw materials used in iron ore sinter plants in Poland. The iron ore sintering process is the largest source of emissions of dust and gas pollution in the iron and steel industry. Hematite ores, magnetite concentrates, admixtures (dolomite, limestone and burnt lime, fuels (coke breeze, anthracite and by-products are used in Poland to produce the sinter mixture.

  14. Chemical composition of Kiscellian silty sediment (sivica from the Trobni Dol area, Eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Miha Mišič

    2003-06-01

    Full Text Available Kiscellian marine silt termed »sivica« is widely developed in Tertiary basins of Eastern Slovenia. Chemical composition is rather uniform and reflects the dominance of filosilicates (mainly illite/muscovite, chlorite and montmorillonite and carbonates. PAAS normalised REE and Y abundances are slightly depleted for La, Ce, Pr and Nd, very close to PAAS for Sm, Eu, Gd and Tb, and depleted for Y, Ho, Er, Tm, Yb and Lu.

  15. Chemical Composition and Antifungal Activity of Ocimum basilicum L. Essential Oil

    OpenAIRE

    Neveen Helmy Abou El-Soud; Mohamed Deabes; Lamia Abou El-Kassem; Mona Khalil

    2015-01-01

    BACKGROUND: The leaves of Ocimum basilicum L. (basil) are used in traditional cuisine as spices; its essential oil has found a wide application in perfumery, dental products as well as antifungal agents. AIM: To assess the chemical composition as well as the in vitro antifungal activity of O. basilicum L. essential oil against Aspergillus flavus fungal growth and aflatoxin B1 production. MATERIAL AND METHODS: The essential oil of O. basilicum was obtained by hydrodistillation and anal...

  16. Chemical composition and antimicrobial activity of the essential oils of Pistacia lentiscus var. chia.

    Science.gov (United States)

    Magiatis, P; Melliou, E; Skaltsounis, A L; Chinou, I B; Mitaku, S

    1999-12-01

    The chemical composition of the three essential oils obtained by steam distillation of the mastic gum, leaves and twigs of Pistacia lentiscus var. chia, was studied by GC/MS. Sixty nine constituents were identified from the oils. alpha-Pinene, myrcene, trans-caryophyllene and germacrene D were found to be the major components. The in vitro antimicrobial activity of the three essential oils and of the resin (total, acid and neutral fraction) against six bacteria and three fungi is reported.

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

    Science.gov (United States)

    Limpens, Juul; Nilsson, Mats

    2014-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Yin Lin

    2014-01-01

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

  19. Differential characteristics in the chemical composition of bananas from Tenerife (Canary Islands) and Ecuador.

    Science.gov (United States)

    Forster, Markus Paul; Rodríguez Rodríguez, Elena; Díaz Romero, Carlos

    2002-12-18

    The contents of moisture, protein, ash, ascorbic acid, glucose, fructose, total sugars, and total and insoluble fiber were determined in cultivars of bananas (Gran Enana and Pequeña Enana) harvested in Tenerife and in bananas (Gran Enana) from Ecuador. The chemical compositions in the bananas from Tenerife and from Ecuador were clearly different. The cultivar did not influence the chemical composition, except for insoluble fiber content. Variations of the chemical composition were observed in the bananas from Tenerife according to cultivation method (greenhouse and outdoors), farming style (conventional and organic), and region of production (north and south). A highly significant (r = 0.995) correlation between glucose and fructose was observed. Correlations of ash and protein contents tend to separate the banana samples according to origin. A higher content of protein, ash, and ascorbic acid was observed as the length of the banana decreased. Applying factor analysis, the bananas from Ecuador were well separated from the bananas produced in Tenerife. An almost total differentiation (91.7%) between bananas from Tenerife and bananas from Ecuador was obtained by selecting protein, ash, and ascorbic acid content and applying stepwise discriminant analysis. By selecting the bananas Pequeña Enana and using discriminant analysis, a clear separation of the samples according to the region of production and farming style was observed.

  20. Composition and Physico-Chemical Properties of Meat from Capons Fed Cereals

    Institute of Scientific and Technical Information of China (English)

    Olga Díaz; Luisana Rodríguez; Alexandr Torres; Ángel Cobos

    2013-01-01

    Chemical composition, physico-chemical properties and fatty acid composition of breast and drumstick meat from capons (castrated male cockerels) fed cereals were studied. Three groups of capons were reared. One group was fed ad libitum the same commercial diet until the 4th mon of life. The last month of its life, the capons of this group were fed corn. The second and third group of capons were fed the same diet from caponization. The second group was fed mixture of corn (50%) and wheat (50%). The third group of capons was fed 2/3 corn and 1/3 mixture of corn (50%) and barley (50%). Capons were reared under free-range conditions and slaughtered at 150 d of age. Caponization was performed at 48 d. No signiifcant effects of feeding in chemical composition, pH, water holding capacity, drip and cooking losses and texture of the meat were observed. The meat of the third group (capons fed 83%corn) was more yellow and showed higher content of C18:2 than that of the other capons.

  1. Chemical composition of crystalline rock fragments from Luna 16 and Luna 20 fines

    Science.gov (United States)

    Cimbalnikova, A.; Palivcova, M.; Frana, J.; Mastalka, A.

    1977-01-01

    The chemical composition (bulk, rare earth, and trace elements) of the Luna 16 mare regolith and luna 20 highland regolith is discussed. The rock samples considered are 14 basaltic rock fragments (Luna 16) and 13 rock fragments of the ANT suite (Luna 20). On the basis of bulk composition, two types of basaltic rocks have been differentiated and defined in the Luna 16 regolith: mare basalts (fundamental crystalline rocks of Mare Fecunditatis) and high-alumina basalts. The bulk analyses of rock fragments of the ANT suite also enabled distinction of two rock types: anorthositic norites and troctolites and/or spinal-troctolites (the most abundant crystalline rocks of the highland region, the landing site of luna 20), and anorthosites. The chemical compositions of Luna 16 and Luna 20 regolith samples are compared. Differences in the chemistry of the Luna 16 mare regolith and that of mare basalts are discussed. The chemical affinity between the Luna 20 highland regolith and (a) anorthositic norites and (b) troctolites and/or spinel-troctolites has been ascertained.

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

    Directory of Open Access Journals (Sweden)

    Gjosheva Melania

    2007-12-01

    Full Text Available Abstract 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 Δ7-sterols. In addition, 5α,8α-Epidioxi-24(ξ-methylcholesta-6,22-diene-3β-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.

  3. Application of infrared spectroscopy for assessing quality (chemical composition) of peatland plants, litter and soil

    Science.gov (United States)

    Straková, Petra; Laiho, Raija

    2016-04-01

    In this presentation, we assess the merits of using Fourier transform infrared (FTIR) spectra to estimate the organic matter composition in different plant biomass and peat soil samples. Infrared spectroscopy has a great potential in large-scale peatland studies that require low cost and high throughput techniques, as it gives a unique "chemical overview" of a sample, with all the chemical compounds present contributing to the spectrum produced. Our extensive sample sets include soil samples ranging from boreal to tropical peatlands, including sites under different environmental and/or land-use changes; above- and below-ground biomass of different peatland plant species; plant root mixtures. We mainly use FTIR to estimate (1) chemical composition of the samples (e.g., total C and N, C:N ratio, holocellulose, lignin and ash content), (2) proportion of each plant species in root mixtures, and (3) respiration of surface peat. The satisfactory results of our predictive models suggest that this experimental approach can, for example, be used as a screening tool in the evaluation of organic matter composition in peatlands during monitoring of their degradation and/or restoration success.

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  5. Electrical performance and chemical composition studies on original and falsified Ni-MH batteries

    Directory of Open Access Journals (Sweden)

    Alexandre Urbano

    2010-12-01

    Full Text Available We show in this paper that falsifications on technological products have hit even rechargeable nickel metal hydride batteries (Ni-MH. The electrical performance and the electrode chemical composition were investigated for authentic and falsified AAA Ni-MH batteries, purchased in the Londrina market, Paraná State. Battery charge capacities were measured at 0,2 C discharge rate and average electrical power was measured at 0.2 and 0.8 C discharge rate. To perform chemical composition analysis, the batteries were vacuum dismantled and their electrodes were characterized by Energy Dispersive X-Ray Fluorescence (EDXRF and X-Ray Diffraction (XRD techniques. It was observed that the charge capacities for the authentic and falsified batteries were 920 and 154 mAh, respectively. The average electrical powers were 210 mW for authentic and 41 mW for falsified batteries. The cathode chemical composition was nickel hydroxide, (Ni(OH2, for both kinds of batteries. However, the anodes of these batteries were not composed by the same materials. The alloy LaNi5 was identified as the electroactive compound in the anode of the authentic battery, while cadmium hydroxide compound, (Cd (OH2, was identified in the falsified battery anode. The authentic battery therefore presented six times more charge capacity, five times more power at 0.2 C discharge rate and 6 times at 0.8 C than the falsified battery, and are yet less dangerous to environment due cadmium absence.

  6. Sequential chemical extraction for a phosphogypsum environmental impact evaluation

    Science.gov (United States)

    Gennari, R. F.; Garcia, I.; Medina, N. H.; Silveira, M. A. G.

    2013-05-01

    Phosphogypsum (PG) is gypsum generated during phosphoric acid production. PG is stocked in large stacks or accumulated in lakes; it contains heavy metals and naturally occurring radioactive elements. The metal contamination may affect the functionality, sustainability and biodiversity of ecosystems. In this work, PG samples were analyzed by Plasma Spectrometry. Total metal content and in the extractable fraction of chemical elements were determined. For K, Ni, Zn, Cr, Cd, Ba, Pb and U, the results obtained are lower than those obtained in a Idaho plant are including and also lower than those found in the soil, indicating this PG sample analyzed probably will not cause any additional metal neither natural radiation contamination.

  7. Scaling of low-velocity impact for symmetric composite laminates

    Science.gov (United States)

    Sankar, Bhavani V.

    1992-01-01

    The equations governing the problem of low-velocity impact of a simply supported rectangular midplane-symmetric laminated plate are nondimensionalized such that the problem is defined in terms of five dimensionless parameters. A parametric study using the Graeco-Latin Factorial Plan is performed. Semi-empirical formulas for maximum impact force, impact duration, and maximum back surface strains are obtained. It is found that some of the simple impact models provide the bounds for the case of impact on a finite extent plate. A one parameter model is derived for impacts of short duration.

  8. Normal mode Rossby waves and their effects on chemical composition in the late summer stratosphere

    Directory of Open Access Journals (Sweden)

    D. Pendlebury

    2007-08-01

    Full Text Available During past MANTRA campaigns, ground-based measurements of several long-lived chemical species have revealed quasi-periodic fluctuations on time scales of several days. These fluctuations could confound efforts to detect long-term trends from MANTRA, and need to be understood and accounted for. Using the Canadian Middle Atmosphere Model, we investigate the role of dynamical variability in the late summer stratosphere due to normal mode Rossby waves and the impact of this variability on fluctuations in chemical species. Wavenumber~1, westward travelling waves are considered with average periods of 5, 10 and 16 days. Time-lagged correlations between the temperature and nitrous oxide, methane and ozone fields are calculated in order to assess the possible impact of these waves on the chemical species, although transport may be the dominant effect. Using Fourier-wavelet decomposition and correlating the fluctuations between the temperature and chemical fields, we determine that variations in the chemical species are well-correlated with the 5-day wave and the 10-day wave between 30 and 60 km. Interannual variability of the waves is also examined.

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

    Science.gov (United States)

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

    2014-01-01

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

  10. Morphology and properties of segregated-network chemically converted graphene-poly(vinyl chloride) composite.

    Science.gov (United States)

    Pham, Viet Hung; Dang, Thanh Truong; Hur, Seung Hyun; Kim, Eui Jung; Chung, Jin Suk

    2012-07-01

    The poly(vinyl chloride)-chemically converted graphene (PVC-CCG) composite prepared using colloidal blending, filtration and drying, and followed by compression molding at 175 degrees C, exhibited an electrical percolation threshold as low as 0.4 wt% and an electrical conductivity as high as 46.5 S/m corresponding to 4.0 wt% of CCG. The high electrical conductivity of the PVC-CCG composite was the result of minimizing the amount of surfactant using various methods. For example, the PVC latex was prepared using miniemulsion polymerization, and the CCG was synthesized via hydrazine reduction of graphene oxide at ambient temperature in order to diminish the irreversible agglomeration of CCG sheets during reduction. The morphology of the PVC-CCG composite, characterized using scanning electron microscopy in charge contrast mode, revealed that the CCG sheets created a segregated network in the PVC matrix.

  11. Marketing research in positioning and launching of yoghurt with a balanced chemical composition

    Directory of Open Access Journals (Sweden)

    M. Mardar

    2016-12-01

    Full Text Available Annotation. This article presents the analysis of marketing environment of the enterprises that produce yogurt products in Ukraine. In order to carry out a deeper analysis of the marketing environment of the new yoghurt drinks with a balanced composition of the major nutrients in food and increased probiotic properties, PEST and SWOT-analyses were conducted, they identified environmental factors that have favorable and adverse effects as well as internal strengths and weaknesses of the new product. Based on the results of marketing research of consumer preferences, the core audience of new yoghurt drink with a balanced chemical composition and the elevated concentration of Bifidobacteria were defined. The received results led to justification of the expediency of elaboration of new yoghurt drinks with probiotic properties and balanced composition of basic food nutrients as well as to formulation of a strategy of new product promotion on the consumer market of Ukraine.

  12. The chemical composition of the Sun from helioseismic and solar neutrino data

    CERN Document Server

    Villante, F L; Delahaye, F; Pinsonneault, M H

    2013-01-01

    We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseimic and solar neutrino data in an effective way. We include in our analysis the helioseismic determinations of the surface helium abundance and of the depth of the convective envelope, the measurements of the $^7{\\rm Be}$ and $^8{\\rm B}$ neutrino fluxes, the sound speed profile inferred from helioseismic frequencies. We provide all the ingredients to describe how these quantities depend on the solar surface composition and to evaluate the (correlated) uncertainties in solar model predictions. We include errors sources that are not traditionally considered such as those from inversion of helioseismic data. We, then, apply the proposed approach to infer the chemical composition of the Sun. We show that the opacity profile of the Sun is well constrained by the solar observational properties. In the context of a two parameter analysis in which elements a...

  13. Influence of Stellar Flares on the Chemical Composition of Exoplanets and Spectra

    CERN Document Server

    Venot, Olivia; Carl, Shaun; Hashim, Aysha; Decin, Leen

    2016-01-01

    More than 3000 exoplanets have been detected so far, and more and more spectroscopic observations of exoplanets are performed. Future instruments are eagerly awaited as they will be able to provide spectroscopic data with a greater accuracy and sensitivity than what is currently available. An important aspect to consider is temporal stellar atmospheric disturbances that can influence the planetary composition, and hence spectra, and potentially can lead to incorrect assumptions about the steady-state atmospheric composition of the planet. We focus on perturbations that come from the host star in the form of flare events that significantly increase the photon flux impingement on the exoplanet atmosphere. In some cases, and particularly for M stars, this sudden increase may last for several hours. We aim at answering the question to what extent a stellar flare is able to modify the chemical composition of the planetary atmosphere and, therefore influence the resulting spectra. We use a 1D thermo-photochemical m...

  14. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An elemental composition method for computation and analysis of simultaneous chemical and phase equilibrium (CPE) of non-ideal mixtures is proposed. The concept of element is defined, the relationship between component composition and elemental composition is derived, and the concept of elemental potential and its physical meaning are further cleared from the view point of thermodynamics. The relationship between chemical potential and elemental potential is derived in the thermodynamic principles, and the computation equations for CPE problem are obtained based on elemental potential. A simple form of necessary and sufficient condition in terms of elemental composition for reactive azeotropes is derived, which takes the same functional form as the condition for azeotropes in non-reactive systems. The element in this note may be atoms, molecules or group radicals. The presented method is applicable to CPE problem of non-ideal mixtures, and the computation can be simplified by the dimension reducing method. The presented method was supplied to compute and analyze CPE problem of several examples and it is found that it is a robust and efficient method.

  16. CHEMICAL COMPOSITION AND SOMATIC CELL EVOLUTION DURING LACTATION IN ROMANIAN BLACK AND WHITE COWS

    Directory of Open Access Journals (Sweden)

    L.T. CZISZTER

    2013-12-01

    Full Text Available The aim of the paper was to study the evolution of the chemical composition and somatic cell count during lactation in Romanian Black and White cows and effect of calving season on the shape of the lactation curve. Lactations form 125 multiparous cows were studied. Milk yield and sampling were carried out using the official performance control method A4. Milk was analyzed for composition in infrared spectrometry and for SCC using a viscosimeter. Results were modeled using Wood’s incomplete gamma function y=abxe(-cx, and season effect was assessed using ANOVA/MANOVA. A discussion was carried out regarding the shape of the lactation curves for milk yield, each milk component and SCC. The calving season had a significant effect (p<0.005 on the shape of the lactation curve for milk yield, milk chemical composition and milk somatic cell count. Summer calving cows had flatter lactation curves for milk yield and composition compared to winter calving cows. For somatic cell count spring calving cows had the flattest lactation curve while autumn calving cows has the steepest lactation curve.

  17. Dittrichia graveolens (L.) Greuter Essential Oil: Chemical Composition, Multivariate Analysis, and Antimicrobial Activity.

    Science.gov (United States)

    Mitic, Violeta; Stankov Jovanovic, Vesna; Ilic, Marija; Jovanovic, Olga; Djordjevic, Aleksandra; Stojanovic, Gordana

    2016-01-01

    The chemical composition and in vitro antimicrobial activities of Dittrichia graveolens (L.) Greuter essential oil was studied. Moreover, using agglomerative hierarchical cluster (AHC) and principal component analyses (PCA), the interrelationships of the D. graveolens essential-oil profiles characterized so far (including the sample from this study) were investigated. To evaluate the chemical composition of the essential oil, GC-FID and GC/MS analyses were performed. Altogether, 54 compounds were identified, accounting for 92.9% of the total oil composition. The D. graveolens oil belongs to the monoterpenoid chemotype, with monoterpenoids comprising 87.4% of the totally identified compounds. The major components were borneol (43.6%) and bornyl acetate (38.3%). Multivariate analysis showed that the compounds borneol and bornyl acetate exerted the greatest influence on the spatial differences in the composition of the reported oils. The antimicrobial activity against five bacterial and one fungal strain was determined using a disk-diffusion assay. The studied essential oil was active only against Gram-positive bacteria.

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

    Science.gov (United States)

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

    2013-01-01

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

  19. Analysis of Chemical Composition of Portland Cement in Ghana: A Key to Understand the Behavior of Cement

    Directory of Open Access Journals (Sweden)

    Mark Bediako

    2015-01-01

    Full Text Available The performance of Portland cement in concrete or mortar formation is very well influenced by chemical compositions among other factors. Many engineers usually have little information on the chemical compositions of cement in making decisions for the choice of commercially available Portland cement in Ghana. This work analyzed five different brands of Portland cement in Ghana, namely, Ghacem ordinary Portland cement (OPC and Portland limestone cement (PLC, CSIR-BRRI Pozzomix, Dangote OPC, and Diamond PLC. The chemical compositions were analyzed with X-Ray Fluorescence (XRF spectrometer. Student’s t-test was used to test the significance of the variation in chemical composition between standard literature values and each of the commercial cement brands. Analysis of variance (ANOVA was also used to establish the extent of variations between chemical compositions and brand name of the all commercial Portland cement brands. Student’s t-test results showed that there were no significant differences between standard chemical composition values and that of commercial Portland cement. The ANOVA results also indicated that each brand of commercial Portland cement varies in terms of chemical composition; however, the specific brands of cement had no significant differences. The study recommended that using any brand of cement in Ghana was good for any construction works be it concrete or mortar formation.

  20. Impact of the composition of polysaccharide composite gels on small molecules diffusion: A rheological and NMR study

    OpenAIRE

    2010-01-01

    The gelation mechanism of carrageenan depends on the amount and nature of the polysaccharide, and is cation sensitive. From a rheological approach, this specificity leads to different textural properties. In composite gels with carrageenans, starch and sucrose, the presence of κ/κ2-carrageenan, even at low levels, has an impact on textural and structural properties. In this study, rheological and diffusion NMR measurements were performed on composite gels to probe gel structure at the macro- ...

  1. KNOWLEDGE OF THE SOIL CHEMICAL COMPOSITION IN AREAS OF ECOLOGICAL SUCCESSION FOREST FIR (Abies guatemalensis REHDER

    Directory of Open Access Journals (Sweden)

    José Vicente Martínez-Arévalo

    2014-01-01

    Full Text Available The Chemical composition ( pH , elements major and minor , % S.B., CIC , % M.O. and N.T on soils in open areas and forest fir (Abies guatemalensis Rehder in a successional gradient was studied. These results were related to vegetation through correlation analysis and Canonical Correspondence analysis. The aim was to show the relationships present between vegetation and soil chemistry through ecological succession in areas of cold climate. The results indicate that the vegetation is composed of 82 species of which 20 are the lower herbaceous layer, 34 the herbaceous layer of the upper, 21 shrubs and seven trees. The chemical characteristics of the soil through five successional stages have only few significant differences and not show a clear tendency to increase according to the degree of ecosystem development. A low percentage of correlations between vegetation and soil chemical characteristics are presented. The correspondence canonical analysis shows that the features that correlate with sites through vegetation are the K, and % S.B. and CIC. One can conclude that the approach of the study of the chemical composition of soils in areas of ecological sequence is complex, especially in high regions where, besides other factors, the temperature and humidity play an important role on the soil-vegetation dynamic.

  2. GC-MS investigation of the chemical composition of honeybee drone and queen larvae homogenate

    Directory of Open Access Journals (Sweden)

    Isidorov Valery A.

    2016-06-01

    Full Text Available Honeybee larva homogenate appears to be underrated and insufficiently explored but this homogenate is an exceptionally valuable honeybee product. Drone larva homogenate is very nutritional due to its high content of proteins, free amino acids, lipids, and carbohydrates. Moreover, the biological characteristics of honeybee larvae indicate the presence of chemical substances that may be pharmacologically active. In spite of the above, the chemical composition of honeybee larva has not gained as much attention as that of other bee products. In this study, the chemical composition of honeybee brood homogenate has been investigated using gas chromatography/mass spectrometry. As a result, it was possible to isolate as many as 115 extractive organic compounds from 6 samples of crude queen and 9 samples of drone homogenate. The main groups of substances extracted from either type of homogenate were composed of free amino acids and carbohydrates. The relative content of amino acids in queen homogenate as well as the share of essential amino acids were found to be higher than in the drone homogenate. Disaccharide trehalose was the dominant sugar in the queen larvae, whilst glucose prevailed in the drone larvae. Comparative chemical analyses of honeybee queen and drone larva homogenates have allowed us to make a preliminary inference about a higher overall value of the former.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-25

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

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

    Science.gov (United States)

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

    2014-09-01

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

  5. Impact of the chemicals, essential for the purification process of strict Fe-hydrogenase, on the corrosion of mild steel.

    Science.gov (United States)

    Rouvre, Ingrid; Gauquelin, Charles; Meynial-Salles, Isabelle; Basseguy, Régine

    2016-06-01

    The influence of additional chemical molecules, necessary for the purification process of [Fe]-hydrogenase from Clostridium acetobutylicum, was studied on the anaerobic corrosion of mild steel. At the end of the purification process, the pure [Fe-Fe]-hydrogenase was recovered in a Tris-HCl medium containing three other chemicals at low concentration: DTT, dithionite and desthiobiotin. Firstly, mild steel coupons were exposed in parallel to a 0.1 M pH7 Tris-HCl medium with or without pure hydrogenase. The results showed that hydrogenase and the additional molecules were in competition, and the electrochemical response could not be attributed solely to hydrogenase. Then, solutions with additional chemicals of different compositions were studied electrochemically. DTT polluted the electrochemical signal by increasing the Eoc by 35 mV 24 h after the injection of 300 μL of control solutions with DTT, whereas it drastically decreased the corrosion rate by increasing the charge transfer resistance (Rct 10 times the initial value). Thus, DTT was shown to have a strong antagonistic effect on corrosion and was removed from the purification process. An optimal composition of the medium was selected (0.5 mM dithionite, 7.5 mM desthiobiotin) that simultaneously allowed a high activity of hydrogenase and a lower impact on the electrochemical response for corrosion tests.

  6. The impact of global aviation NOx emissions on tropospheric composition changes from 2005 to 2011

    Science.gov (United States)

    Wasiuk, D. K.; Khan, M. A. H.; Shallcross, D. E.; Lowenberg, M. H.

    2016-09-01

    The impact of aviation NOx emissions from 2005 to 2011 on the chemical composition of the atmosphere has been investigated on the basis of integrations of the 3-D global chemical and transport model, STOCHEM-CRI with the novel CRIv2-R5 chemistry scheme. A base case simulation without aircraft NOx emissions and integrations with NOx emissions from aircraft are inter-compared. The sensitivity of the global atmosphere to varying the quantity and the geographical distribution of the global annual aviation NOx emissions is assessed by performing, for the first time, a series of integrations based on changing the total mass and distribution of aircraft NOx emissions derived from air traffic movements recorded between 2005 and 2011. The emissions of NOx from the global fleet based on actual records of air traffic movements between 2005 and 2011 increased the global tropospheric annual mean burden of O3 by 1.0 Tg and decreased the global tropospheric annual mean burden of CH4 by 2.5 Tg. The net NOy and O3 production increases by 0.5% and 1%, respectively between 2005 and 2011 in total. At cruise altitude, the absolute increase in the modelled O3 mixing ratios is found to be up to 0.7 ppb between 2005 and 2011 at 25°N-50°N.

  7. The free radical chemistry of cloud droplets and its impact upon the composition of rain

    Science.gov (United States)

    Chameides, W. L.; Davis, D. D.

    1982-01-01

    Calculations are presented that simulate the free radical chemistries of the gas phase and aqueous phase within a warm cloud during midday. It is demonstrated that in the presence of midday solar fluxes, the heterogeneous scavenging of OH and HO2 from the gas phase by cloud droplets can represent a major source of free radicals to cloud water, provided the accommodation or sticking coefficient for these species impinging upon water droplets is not less than 0.0001. The aqueous-phase of HO2 radicals are found to be converted to H2O2 by aqueous-phase chemical reactions at a rate that suggests that this mechanism could produce a significant fraction of the H2O2 found in cloud droplets. The rapid oxidation of sulfur species dissolved in cloudwater by this free-radical-produced H2O2 as well as by aqueous-phase OH radicals could conceivably have a significant impact upon the chemical composition of rain.

  8. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites

    Science.gov (United States)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.

    2016-09-01

    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  9. The cryogenic bonding evaluation at the metallic-composite interface of a composite overwrapped pressure vessel with additional impact investigation

    Science.gov (United States)

    Clark, Eric A.

    A bonding evaluation that investigated the cryogenic tensile strength of several different adhesives/resins was performed. The test materials consisted of 606 aluminum test pieces adhered to a wet-wound graphite laminate in order to simulate the bond created at the liner-composite interface of an aluminum-lined composite overwrapped pressure vessel. It was found that for cryogenic applications, a flexible, low modulus resin system must be used. Additionally, the samples prepared with a thin layer of cured resin -- or prebond -- performed significantly better than those without. It was found that it is critical that the prebond surface must have sufficient surface roughness prior to the bonding application. Also, the aluminum test pieces that were prepared using a surface etchant slightly outperformed those that were prepared with a grit blast surface finish and performed significantly better than those that had been scored using sand paper to achieve the desired surface finish. An additional impact investigation studied the post impact tensile strength of composite rings in a cryogenic environment. The composite rings were filament wound with several combinations of graphite and aramid fibers and were prepared with different resin systems. The rings were subjected to varying levels of Charpy impact damage and then pulled to failure in tension. It was found that the addition of elastic aramid fibers with the carbon fibers mitigates the overall impact damage and drastically improves the post-impact strength of the structure in a cryogenic environment.

  10. Impact History on Vesta: Petrographic, Compositional and Future Chronological Studies of Melt Clasts in Howardites

    Science.gov (United States)

    Cartwright, J. A.; Mittlefehldt, D. W.; Hodges, K. V.; Wadhwa, M.

    2015-01-01

    Howardite meteorites are polymict breccias composed mainly of eucritic and diogenitic material that likely originate from the surface of the Asteroid 4 Vesta. They can be separated into two subtypes: Regolithic, which represent the lithified remains of the active vestan regolith; Fragmental, which represent simpler polymict breccias. Amongst the regolithic features observed in the former, melt clasts are particularly striking for their appearance and compositional variability. They range from glassy spherules to finely crystalline (i.e., devitrified) clasts, and clasts containing only relict mineral grains to those containing only phenocrysts. Glasses can be separated into compositional sub-types including those with low FeO/MgO ratios (less than 5) -low alkali glasses, K-rich (K2O greater than 0.2 wt.%), Na-rich (Na2O greater than 0.6 wt.%) and CaO-rich, and those with high FeO/MgO ratios (greater than 10). There is also a distinction to be made between primary volcanic melt clasts and those produced by impacts. While suggested that a lack of chemical homogeneity among their studied melt clasts ruled out a primary volcanic origin, the low siderophile element contents observed in such clasts suggest less compositional influence from impactors than commonly assumed. Studying the chronology of the impact melt clasts in howardites can help us to better determine the timing of impact events on Vesta and the asteroid belt. In this research, we are launching an investigation into the petrology, composition (major/trace element and noble gas) and chronology of melt clasts in howardites. We have selected a set of howardites known to contain large quantities of melt clasts, and have begun the petrological and compositional studies of these materials. Once the melt clasts have been fully classified, we aim to perform chronological studies of individual clasts using both the Ar-40/Ar-39 and Pb-Pb chronometers, as well as determine the noble gas components present. Of

  11. Influence of Stacking Sequence on the Impact and Postimpact Bending Behavior of Hybrid Sandwich Composites

    Science.gov (United States)

    Özen, M.

    2017-01-01

    A new hybrid sandwich structure was developed by using carbon, e-glass, and s-glass fabrics as reinforcement materials, an epoxy resin as the matrix material for face sheets, and a PVC foam as the core material. Six different configurations were prepared. Sandwich composites plates with different stacking sequences were subjected to low-speed impacts will energies of 7.5, 15, and 22.5 J. Their impact response is analyzed and reported in terms of the peak load as a function of impact energy. After impact tests, 3-point bending tests were conducted to determine the bending behavior of the sandwich composites after impacts in terms of their flexural strength. The results obtained showed that the use of carbon fabrics in the face sheets increased the peak loads for all the impact energies considered. The presence of carbon fibers in skin regions increased the flexural strength of the composites, but e-glass fibers decreased this strength.

  12. Impact behaviour of Napier/polyester composites under different energy levels

    Science.gov (United States)

    Fahmi, I.; Majid, M. S. Abdul; Afendi, M.; Haslan, M.; Helmi E., A.; M. Haameem J., A.

    2016-07-01

    The effects of different energy levels on the impact behaviour of Napier fibre/polyester reinforced composites were investigated. Napier fibre was extracted using traditional water retting process to be utilized as reinforcing materials in polyester composite laminates. 25% fibre loading composite laminates were prepared and impacted at three different energy levels; 2.5,5 and 7.5 J using an instrumented drop weight impact testing machine (IMATEK IM10). The outcomes show that peak force and contact time increase with increased impact load. The energy absorption was then calculated from the force displacement curve. The results indicated that the energy absorption decreases with increasing energy levels of the impact. Impacted specimens were observed visually for fragmentation fracture using an optical camera to identify the failure mechanisms. Fracture fragmentation pattern from permanent dent to perforation with radial and circumferential was observed.

  13. Managing the effects of endocrine disrupting chemicals in wastewater-impacted streams

    Science.gov (United States)

    Bradley, Paul M.; Kolpin, Dana W.

    2013-01-01

    A revolution in analytical instrumentation circa 1920 greatly improved the ability to characterize chemical substances. This analytical foundation resulted in an unprecedented explosion in the design and production of synthetic chemicals during and post-World War II. What is now often referred to as the 2nd Chemical Revolution has provided substantial societal benefits; with modern chemical design and manufacturing supporting dramatic advances in medicine, increased food production, and expanding gross domestic products at the national and global scales as well as improved health, longevity, and lifestyle convenience at the individual scale. Presently, the chemical industry is the largest manufacturing sector in the United States (U.S.) and the second largest in Europe and Japan, representing approximately 5% of the Gross Domestic Product (GDP) in each of these countries. At the turn of the 21st century, the chemical industry was estimated to be worth more than $1.6 trillion and to employ over 10 million people, globally. During the first half of the 20th century, the chemical sector expanded rapidly, the chemical industry enjoyed a generally positive status in society, and chemicals were widely appreciated as fundamental to individual and societal quality of life. Starting in the 1960s, however, the environmental costs associated with the chemical industry increasingly became the focus, due in part to the impact of books like “Silent Spring” and “Our Stolen Future” and to a number of highly publicized environmental disasters. Galvanizing chemical industry disasters included the 1976 dioxin leak north of Milan, Italy, the Love Canal evacuations in Niagara, New York beginning in 1978, and the Union Carbide leak in Bhopal, India in 1984. Understanding the environmental impact of synthetic compounds is essential to any informed assessment of net societal benefit, for the simple reason that any chemical substance that is in commercial production or use will

  14. Evaluation of the impact response of textile composites

    Science.gov (United States)

    Portanova, M. A.

    1995-01-01

    An evaluation of the impact damage resistance and impact damage tolerance of stitched and unstitched uniweaves, 2-D braids, and 3-D weaves was conducted. Uniweave laminates were tested at four thicknesses to determine the sensitivity of the tests to this parameter. Several braid and weave parameters were also varied to establish their velocity (large mass) impacts and then loaded in tension or compression to measure residual strength. Experimental results indicate that stitching significantly improves the uniweaves' damage resistance. The 2-D braids and 3-D weaves offered less damage resistance than the stitched materials. Stitching also improved the compression after impact (CAI) and tension after impact (TAI) strengths of the uniweave materials.

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

    Science.gov (United States)

    Yeşim Tunçel, Derya; Kerim Kara, Mustafa; Özel, Emel

    2011-10-01

    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).

  16. X-ray photoelectron spectroscopy for wheat powders: measurement of surface chemical composition.

    Science.gov (United States)

    Saad, Moustafa; Gaiani, Claire; Mullet, Martine; Scher, Joel; Cuq, Bernard

    2011-03-09

    The functional properties of wheat powders depend largely on the surface characteristics of their particles. X-ray photoelectron spectroscopy (XPS) has been considered to investigate the surface composition of wheat powders. The objective of the present study is to evaluate the ability of XPS to discriminate wheat components and to calculate the surface composition of wheat powders. First, XPS surveys for the main wheat isolated components (starch, proteins, arabinoxylans, and lipids) were determined. XPS results demonstrate that it is able to distinguish wheat proteins, polysaccharides, and lipids, but it is not able to distinguish starch and arabinoxylan because of their similarity in chemical structure. The XPS analyses of simple reconstituted wheat flours based on two components (starch and protein) or three components (by adding arabinoxylan) demonstrated the ability of XPS to measure the surface composition of the wheat flours. The surface composition of native wheat flour demonstrated an overrepresentation of protein (54%) and lipids (44%) and an underrepresentation of starch (2%) compared to the bulk composition. Results are discussed with regard to difficulties in discriminating arabinoxylans and starch components.

  17. Chemical composition of Pleurotus pulmonarius (Fr. Quél., substrates and residue after cultivation

    Directory of Open Access Journals (Sweden)

    Silva Sueli Oliveira

    2002-01-01

    Full Text Available The cultivation of Pleurotus pulmonarius was carried out on different substrate: cotton waste (A leaves of Cymbopogon citratus (B and leaves of Panicum maximum Jacq. (C. The mushroom had a varied chemical composition; nevertheless they contained a good composition for to be used as a good source of protein for human kind. The results showed the higher protein content (29.19% and fibre (9.0% for the mushroom that were cultivated on cotton peel. The substrate composition and the residue composition after the mushroom harvest were: Protein for the substrate "A" (10.63% and 9.35%, "B" (7.87% and 4.24% and "C" (7.55% and 5.90 %; Lipids "A" (4.17% and 2.03%, "B"(2.77% and 3.20% and "C" (0.91% and 2.05%; Fibres "A" (49.02% and 37.02%, "B" (28.40% and 23.26% and "C" (37.50% and 26.66% respectively. The substrate "A" showed 0.048% of iron and "C" 0.14% of magnesium, 0.31% of potassium and 0.26% of calcium. In the substrate "B" the quantity of the minerals were very low in comparison to the other substrates. The residues after the harvest of mushroom could be used as fertiliser or as complement in the composition for animal feed.

  18. Impact and dynamic mechanical thermal properties of textile silk reinforced epoxy resin composites

    Science.gov (United States)

    Yang, K.; Guan, J.

    2016-07-01

    Silk fabric reinforced epoxy resin composites (SFRPs) were prepared using simple techniques of hand lay-up, hot-press and vacuum treatment, and a series of volume fractions of silk reinforcements were achieved. The impact properties and dynamic mechanical properties of SFRPs were investigated using a pendulum impact testing method and dynamic mechanical thermal analysis (DMTA). The results suggest that silk reinforcement could greatly enhance the mechanical performances of SFRPs. The impact strength reached a maximum of 71 kJ/m2 for 60%-silk SFRP, which demonstrated a potential of silk composites for defence and impact- resistant materials.

  19. Chemical Mechanical Polishing of Glass Substrate with α-Alumina-g-Polystyrene Sulfonic Acid Composite Abrasive

    Institute of Scientific and Technical Information of China (English)

    LEI Hong; BU Naijing; ZHANG Zefang; CHEN Ruling

    2010-01-01

    Abrasive is the one of key influencing factors during chemical mechanical polishing(CMP) process. Currently, α-Alumina (α-Al2O3) particle, as a kind of abrasive, has been widely used in CMP slurries, but their high hardness and poor dispersion stability often lead to more surface defects. After being polished with composite particles, the surface defects of work pieces decrease obviously. So the composite particles as abrasives in slurry have been paid more attention. In order to reduce defect caused by pure α-Al2O3 abrasive, α-alumina-g-polystyrene sulfonic acid (α-Al2O3-g-PSS) composite abrasive was prepared by surface graft polymerization. The composition, structure and morphology of the product were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), time-of-flight secondary ion mass spectroscopy(TOF-SIMS), and scanning electron microscopy(SEM), respectively. The results show that polystyrene sulfonic acid grafts onto α-Al2O3, and has well dispersibility. Then, the chemical mechanical polishing performances of the composite abrasive on glass substrate were investigated with a SPEEDFAM-16B-4M CMP machine. Atomic force microscopy(AFM) images indicate that the average roughness of the polished glass substrate surface can be decreased from 0.835 nm for pure α-Al2O3 abrasive to 0.583 nm for prepared α-Al2O3-g-PSS core-shell abrasive. The research provides a new and effect way to improve the surface qualities during CMP.

  20. Control of environmental impact with modern chemical technology

    Science.gov (United States)

    Hocking, Martin B.

    1986-03-01

    Here are assembled representative excerpts from a new text in applied chemistry. They illustrate the well-referenced treatment of industrial processes that are here considered with their related emission control problems and solutions. A brief account of general aspects of the industry is followed by surveys of the significance and technical aspects of air and water pollution chemistry. Consideration is given to emission avoidance or containment, waste treatment, and waste disposal options as they relate to both of these environmental areas. Details of salt recovery and the products of brine electrolysis plus environmental aspects of these operations are treated as examples of some of the processes discussed. Also covered are fertilizer constituent preparation, formulation, and use with consideration of the large-scale effects of each of these activities. Detailed reference is made to the chemical technology and emission control aspects of the pulp and paper industry and refinery operations. Throughout, integral process changes and waste recycling practices are directly related to emission control aspects of each process in a way to be useful to the student and professional alike. These excerpts are extracted from one of the first, single volume accounts to take this unified approach to the subject.

  1. Impact and residual fatigue behavior of ARALL and AS6/5245 composite materials

    Science.gov (United States)

    Johnson, W. S.

    1986-01-01

    Aramide fiber reinforced aluminum laminates (ARALL) represent a cross between resin matrix composites and metals. The purpose of this study was to evaluate the impact sensitivity of this concept. Two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained) were tested through static indentation and the results compared to sheet 2024-T3 and 7075-T6 aluminum alloys. A state-of-the-art composite (AS6/5245) was also tested and compared to the ARALL. Further, the two types of ARALL material and the composite were dynamically impacted at two energy levels and fatigue tested to determine residual fatigue strength. Both forms of the ARALL material had worse impact resistance than monolithic sheet aluminum. The ARALL material made with 2024-T3 aluminum had better impact resistance than did the laminates made with 7075-T6 aluminum. The ARALL materials are at least equal to the composite material in impact damage resistance and are better for impact detection. The composite material has higher residual fatigue strength after impact than the ARALL material and is 25 percent lighter. The prestraining of the ARALL greatly reduces the fatigue growth of impact damage.

  2. How much information do extinction and backscattering measurements contain about the chemical composition of atmospheric aerosol?

    Science.gov (United States)

    Kahnert, Michael; Andersson, Emma

    2017-03-01

    We theoretically and numerically investigate the problem of assimilating multiwavelength lidar observations of extinction and backscattering coefficients of aerosols into a chemical transport model. More specifically, we consider the inverse problem of determining the chemical composition of aerosols from these observations. The main questions are how much information the observations contain to determine the particles' chemical composition, and how one can optimize a chemical data assimilation system to make maximum use of the available information. We first quantify the information content of the measurements by computing the singular values of the scaled observation operator. From the singular values we can compute the number of signal degrees of freedom, Ns, and the reduction in Shannon entropy, H. As expected, the information content as expressed by either Ns or H grows as one increases the number of observational parameters and/or wavelengths. However, the information content is strongly sensitive to the observation error. The larger the observation error variance, the lower the growth rate of Ns or H with increasing number of observations. The right singular vectors of the scaled observation operator can be employed to transform the model variables into a new basis in which the components of the state vector can be partitioned into signal-related and noise-related components. We incorporate these results in a chemical data assimilation algorithm by introducing weak constraints that restrict the assimilation algorithm to acting on the signal-related model variables only. This ensures that the information contained in the measurements is fully exploited, but not overused. Numerical tests show that the constrained data assimilation algorithm provides a solution to the inverse problem that is considerably less noisy than the corresponding unconstrained algorithm. This suggests that the restriction of the algorithm to the signal-related model variables suppresses

  3. The chemical compositions of solar twins in the open cluster M67

    Science.gov (United States)

    Liu, F.; Asplund, M.; Yong, D.; Meléndez, J.; Ramírez, I.; Karakas, A. I.; Carlos, M.; Marino, A. F.

    2016-11-01

    Stars in open clusters are expected to share an identical abundance pattern. Establishing the level of chemical homogeneity in a given open cluster deserves further study as it is the basis of the concept of chemical tagging to unravel the history of the Milky Way. M67 is particularly interesting given its solar metallicity and age as well as being a dense cluster environment. We conducted a strictly line-by-line differential chemical abundance analysis of two solar twins in M67: M67-1194 and M67-1315. Stellar atmospheric parameters and elemental abundances were obtained with high precision using Keck/High Resolution Echelle Spectrometer spectra. M67-1194 is essentially identical to the Sun in terms of its stellar parameters. M67-1315 is warmer than M67-1194 by ≈150 K as well as slightly more metal-poor than M67-1194 by ≈0.05 dex. M67-1194 is also found to have identical chemical composition to the Sun, confirming its solar-twin nature. The abundance ratios [X/Fe] of M67-1315 are similar to the solar abundances for elements with atomic number Z ≤ 30, while most neutron-capture elements are enriched by ≈0.05 dex, which might be attributed to enrichment from a mixture of asymptotic giant branch ejecta and r-process material. The distinct chemical abundances for the neutron-capture elements in M67-1315 and the lower metallicity of this star compared to M67-1194, indicate that the stars in M67 are likely not chemically homogeneous. This poses a challenge for the concept of chemical tagging since it is based on the assumption of stars forming in the same star-forming aggregate.

  4. Research on Mechanical Behaviors of Micro-crystal Muscovite/UHMWPE Composites to Impact Loading

    Directory of Open Access Journals (Sweden)

    Hu Huarong

    2016-01-01

    Full Text Available UHMWPE composites were prepared by hot pressing process with micro-crystal muscovite as reinforced particulates. The mechanical behaviors of composites to impact loading was evaluated by split Hopkinson bar. The results demonstrated that dynamic yield stress and failure stress of UHMWPE composites were gradually increased when the filling amount was less than 20%; when the filling content of muscovite was around 15%, the energy absorption efficiency of the composite reaches maximum value. It was also found that when strain rate within 3200/s, the dynamic yield stress, failure stress and energy absorption efficiency of UHMWPE composites increased with the increase of strain rate and display strain rate enhancement effect.

  5. Experimental Study of the Impact Damage of Composition B and Plastic Bonded Explosive

    Institute of Scientific and Technical Information of China (English)

    陈鹏万; 黄风雷; 丁雁生

    2003-01-01

    A long-pulse low-velocity gas gun with a gas buffer is used to induce impact damage in cast Composition B and hot pressed PBXN-5. To obtain different damage states, a range of projectile velocities are used by controlling the launching pressure of gas gun. The stress history during impact loading is recorded. Various methods are used to characterize the damage state of impacted explosive samples. The microstructure is examined by use of scanning electronic microscopy (SEM) and polarized light microscopy (PLM). The densities and ultrasonic attenuation are also measured. The results show that both Composition B and PBXN-5 exhibit some damage characteristics of brittle materials. However, due to the difference in compositions, PBXN-5 exhibits better resistance to impact loading than Composition B.

  6. Preliminary Study on Evaluation System of Capability of Composites to Withstand Impact

    Institute of Scientific and Technical Information of China (English)

    SHEN Zhen; CHEN Pu-hui; YANG Sheng-chun

    2006-01-01

    This paper summarizes the authors' experimental study on the characterization system of composite behavior to withstand impact. The content includes: (1)The dent depth is the best parameter describing the impact damage state. (2) There exists the knee point phenomenon for damage resistance behavior (i. e. the relationship between impact energy or contact force and dent depth) and damage tolerance behavior (i. e. the relationship between dent depth and compressive failure strain or stress) of composite laminates. (3) The physical meaning of the knee point phenomenon is that the failure mechanisms change of damaged composites to fiber breakage in the first front plies from matrix crack and delamination.Some suggestions on the characterization system of composite behavior to withstand impact were proposed.

  7. Chemical composition of aerosol in the atmospheric surface layer of the East Antarctica coastal zone

    Directory of Open Access Journals (Sweden)

    L. P. Golobokova

    2016-01-01

    Full Text Available Chemical composition of aerosol in the ground layer of the coastal zone in East Antarctica is analyzed in the article. The aerosol samples were taken in 2006–2015 during seasonal works of the Russian Antarctic Expeditions (RAE, namely, these were 52nd–53rd, 55th, and 58th–60th expeditions. Samples were taken in the 200‑km band of the sea-shore zone along routes of the research vessels (REV «Akademik Fedorov» and «Akademik Treshnikov» as well as on territories of the Russian stations Molodezhnaya and Mirny. Although the results obtained did show the wide range of the aerosol concentrations and a certain variability of their chemical composition, some common features of the variability were revealed. Thus, during the period from 2006 to 2014 a decrease of average values of the sums were noted. Spatially, a tendency of decreasing of the ion concentrations was found in the direction from the station Novolazarevskaya to the Molodezhnaya one, but the concentrations increased from the Molodezhnaya to the station Mirny. The sum of ions of the aerosol in the above mentioned coastal zone was, on the average, equal to 2.44 μg/m3, and it was larger than that on the territory of the Antarctic stations Molodezhnaya (0,29 μg/m3 and Mirny (0,50 ág / m3. The main part to the sum of the aerosol ions on the Antarctic stations was contributed by Na+, Ca2+, Cl−, SO4 2−. The main ions in aerosol composition in the coastal zone are ions Na+ and Cl−. The dominant contribution of the sea salt and SO4 2− can be traced in not only the composition of atmospheric aerosols, but also in the chemical composition of the fresh snow in the coastal areas of East Antarctica: at the Indian station Maitri, on the Larsemann Hills, and in a boring located in 55.3 km from the station Progress (K = 1.4÷6.1. It was noted that values of the coefficient of enrichment K of these ions decreases as someone moves from a shore to inland. Estimation of

  8. Chemical composition and amino acid profile of differently processed feather meal

    Directory of Open Access Journals (Sweden)

    Adejumo Oluseun Isaac

    2016-01-01

    Full Text Available Feather wastes represent potential alternative ingredients for animal feedstuffs which can ameliorate the protein shortage for food and feed. Previous attempts to provide information about the nutrient composition of feather meal are either too complicated for rural livestock farmers in developing countries or they provided incomplete information on chemical composition. Washed feathers were subjected to different processing techniques such as pre-soaking in distilled water, wood ash, 0.3M NaOH, a mixture of wood ash and 0.3M NaOH, incubated at 37°C and boiled at 150°C for 60 minutes. Treated feather meals were analysed for chemical composition and amino acid profile. The overall result showed that feather meal pre-soaked with wood ash for 24 hr boiled at 150oC for 60 minutes, those pre-soaked with 0.3M NaOH and wood ash incubated at 37°C for 24 hr boiled at 150°C for 60 minutes and raw feather meal pre-soaked in distilled water for 24 hr boiled at 150°C for 60 minutes gave better results. Wood ash and 0.3M NaOH and their mixture could enhance the nutritional value of feather meal.

  9. The Influence of Nanoadditives on the Biological Properties and Chemical Composition of Process Fluids

    Directory of Open Access Journals (Sweden)

    Borůvková K.

    2015-12-01

    Full Text Available In this study process fluids were tested after the addition of nanoparticles. Cooling and lubricating process fluids are used in machining to reduce wear on tools, to increase machine performance and to improve product quality. The use of process fluids leads to their pollution and contamination. Nanoparticles were added to the process fluids in order to increase their antibacterial activity. The selected nanoparticles were nanoparticles of metallic silver. The process fluids were modified by the addition of silver nitrate and ascorbic acid. Reduction of silver nanoparticles in the volume of the fluid was achieved using UV. The modified fluids were tested for their cytotoxicity and changes in chemical composition. The cytotoxicity of process fluids was tested for the purpose of verifying whether the process fluids, which are in direct contact with the skin of the operator, affect the health of the operator. The cytotoxicity of the process fluids was tested on human fibroblast cells. Fibroblasts are the basic cells of fibrous tissue. The cytotoxicity was tested by measuring the cell viability and using XTT. Analysis of chemical composition was performed for the purpose of determining the individual substances in the process fluids and their chemical stability. Qualitative analysis of the process fluids was performed using gas chromatography mass spectrometry (GC - MS.

  10. The Composition of the Sagittarius Dwarf Spheroidal Galaxy and Implications for Nucleosynthesis and Chemical Evolution

    CERN Document Server

    McWilliam, A; William, Andrew Mc; Smecker-Hane, Tammy A.

    2004-01-01

    We outline the results of a study of the chemical composition of 14 stars in the Sagittarius dwarf spheroidal galaxy (Sgr dSph). For the Sgr dSph stars with [Fe/H]>-1 the abundances are highly unusual, showing a striking enhancement in heavy s-process elements, increasing with [Fe/H], deficiencies of the alpha- elements (O, Si, Ca, and Ti), deficiencies of Al and Na, and deficiencies of the iron-peak elements Mn and Cu. Our abundances suggest that the composition of the metal-rich Sgr dSph stars is dominated by the ejecta of an old, metal-poor population, including products of AGB stars and type Ia supernovae (SN). We suggest two scenarios to explain the observations: Prolonged chemical evolution in a galaxy experiencing significant mass-loss, and chemical enrichment with episodic bursts of star formation. The Galactic globular cluster Omega Cen, and the Fornax dwarf galaxy show similar abundance patterns, which suggests that those systems evolved similar to the Sgr dSph.

  11. Chemical composition of essential oils of leaves, flowers and fruits of Hortia oreadica

    Directory of Open Access Journals (Sweden)

    Danillo L. Santos

    2016-02-01

    Full Text Available Abstract Hortia oreadica Groppo, Kallunki & Pirani, Rutaceae, known as “para-tudo”, “quina”, and “quina-do-campo”, is used in traditional medicine locally to treat stomach pain and fevers. The aims of this study were: analyze the chemical composition of essential oils from leaves, flowers and fruits of H. oreadica and verify the seasonal variation of the chemical components of essential oils from leaves. The essential oils were obtained by hydrodistillation using a Clevenger type apparatus and analyzed by GC/MS. The major components found in the samples of the essential oils were the amorpha-4,7(11-diene (29.27% – flowers, 20.26% – fruits, 27.66–37.89% – leaves, bicyclogermacrene (23.28% – flowers, 20.64% – fruits, 14.71% to 31.37% – leaves. This work represents the first study of the chemical composition of essential oils from leaves, flowers and fruits and seasonal variation in the essential oils from leaves of H. oreadica.

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

    Science.gov (United States)

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

    2008-12-01

    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.

  13. Organic and mineral fertilization and chemical composition of lemon balm (Melissa officinalis essential oil

    Directory of Open Access Journals (Sweden)

    Ana Carolina B. Sodré

    2012-02-01

    Full Text Available Melissa officinalis L., Lamiaceae, is an herb with great growth prospects in the cosmetic industry due to its essential oil. In order to improve its production, it is necessary to study related agricultural practices. This study evaluated the effect of organic and mineral fertilization on the chemical composition of lemon balm (Melissa officinalis L. essential oil. The assay was conducted at the "Fazenda Experimental do Glória" of the Federal University of Uberlândia, and essential oil extraction and GC/MS analyses were completed by the Centre for Research and Development on Plant Genetic Resources of the Campinas Agronomic Institute. The assay was conducted in a randomized complete block design with three replications. The tested treatments were six types of fertilization (0, 1, 2, 4, 8 kg.m-2 of cattle manure and mineral fertilizing with 60 g.m-2 of NPK 4-14-8 + 4 g.m-2 of boric acid with four replications. The essential oil was extracted by hydrodistillation in a modified Clevenger apparatus. The chemical composition was analyzed by GC/MS. The essential oil presented the same compounds for all treatments; however, the relative proportion of some chemical constituents was altered according to the treatment. Neral, geranial, and citronellal were the major constituents.

  14. Chemical Composition and Vasorelaxant and Antispasmodic Effects of Essential Oil from Rosa indica L. Petals

    Directory of Open Access Journals (Sweden)

    Hafiz Majid Rasheed

    2015-01-01

    Full Text Available Rosa indica L. belongs to the family Rosaceae and is locally known as gulaab. It has different traditional uses in cardiovascular and gastrointestinal disorders but there is no scientific data available in this regard. Therefore, the basic aim of this study was to explore the chemical composition and gastrointestinal and cardiovascular effects of the essential oil obtained from R. indica. The chemical composition of the essential oil was investigated using gas chromatography-mass spectrometry (GC-MS technique. The cardiovascular and gastrointestinal effects were investigated using electrophysiological measurements. The GC-MS analysis of the essential oil showed various chemical components including acetic acid, mercaptohexyl ester, butanoic acid, 2-methyl-5-oxo-1-cyclopentene-1-yl ester, artemiseole, methyl santonilate, isosteviol, caryophyllene oxide, pentyl phenyl acetate, dihydromyrcene, 1,5-octadecadien, octadecanoic acid, ethyl ester, palmitic acid (2-phenyl-1,3-dioxolan-4-yl methyl ester, santolina epoxide, and 9-farnesene. The electrophysiological measurements revealed that essential oil was more potent against K+ (80 mM than phenylephrine precontractions using isolated rabbit aorta preparations. In isolated rabbit jejunum preparations, it showed more potency against high K+ induced contractions than spontaneous contractions. Considering these evidences, it can be concluded that R. indica essential oil may work as a complementary and alternative medicine in gastrointestinal and cardiovascular diseases.

  15. Influence of Stellar Flares on the Chemical Composition of Exoplanets and Spectra

    Science.gov (United States)

    Venot, Olivia; Rocchetto, Marco; Carl, Shaun; Roshni Hashim, Aysha; Decin, Leen

    2016-10-01

    More than three thousand exoplanets have been detected so far, and more and more spectroscopic observations of exoplanets are performed. Future instruments (James Webb Space Telescope (JWST), E-ELT, PLATO, Ariel, etc.,) are eagerly awaited, as they will be able to provide spectroscopic data with greater accuracy and sensitivity than what is currently available. This will allow more accurate conclusions to be drawn regarding the chemistry and dynamics of exoplanetary atmospheres, provided that the observational data are carefully processed. One important aspect to consider is temporal stellar atmospheric disturbances that can influence the planetary composition, and hence spectra, and potentially can lead to incorrect assumptions about the steady-state atmospheric composition of the planet. In this paper, we focus on perturbations coming from the host star in the form of flare events that significantly increase photon flux impingement on the exoplanets atmosphere. In some cases, particularly for M stars, this sudden increase may last for several hours. We aim to discover to what extent a stellar flare is able to modify the chemical composition of the planetary atmosphere and, therefore, influence the resulting spectra. We use a one-dimensional thermo-photochemical model to study the neutral atmospheric composition of two hypothetical planets located around the star AD Leo. We place the two planets at different distances from the star, which results in effective atmospheric temperatures of 412 and 1303 K. AD Leo is an active star that has already been observed during a flare. Therefore, we use the spectroscopic data from this flare event to simulate the evolution of the chemical composition of the atmospheres of the two hypothetical planets. We compute synthetic spectra to evaluate the implications for observations. The increase in the incoming photon flux affects the chemical abundances of some important species (such as H and NH3), down to altitudes associated with

  16. Relationship between chemical composition and biological function of Pseudomonas aeruginosa lipopolysaccharide: effect on human neutrophil chemotaxis and oxidative burst

    DEFF Research Database (Denmark)

    Kharazmi, A; Fomsgaard, A; Conrad, R S;

    1991-01-01

    There are conflicting data on the effect of bacterial lipopolysaccharides (LPS) on the function of human neutrophils. The present study was designed to examine the relationship between chemical composition and the modulatory effect of LPS on human neutrophil function. LPS was extracted from five ...... composition of the LPS molecule may play an important role in biological activity of LPS.......There are conflicting data on the effect of bacterial lipopolysaccharides (LPS) on the function of human neutrophils. The present study was designed to examine the relationship between chemical composition and the modulatory effect of LPS on human neutrophil function. LPS was extracted from five...... no effect on neutrophil chemotaxis and a slight effect on chemiluminescence. The major differences in chemical composition of the LPS from these two strains are in the rhamnose and heptose content of the O side chain and in the alanine content of the core region. These data indicate that chemical...

  17. Chemical composition and biological activity of essential oils of Dracocephalum heterophyllum and Hyssopus officinalis from Western Himalaya

    Science.gov (United States)

    The essential oils of two representatives of the Lamiaceae-family, Dracocephalum heterophyllum Benth. and Hyssopus officinalis L., are described for their antifungal, antibacterial and larvicidal as well as biting deterrent activities. Additionally, the essential oils’ chemical compositions, analyze...

  18. Evaluation of progressive damage of nano-modified composite laminates under repeated impacts

    Science.gov (United States)

    Koricho, Ermias G.; Karpenko, Oleksii; Khomenko, Anton; Haq, Mahmoodul; Cloud, Gary L.; Udpa, Lalita

    2016-04-01

    However, studies on the effect of nano-reinforcements in repeated impact scenarios are relatively limited. This work investigates the effect of resin nanoclay modification on the impact resistance of glass-fiber reinforced polymer (GFRP) composites subjected to repeated impacts. Three impact energy levels were used in experiments with a minimum of four specimens per case for statistical significance. Each sample was subjected to 40 repeated impacts or was tested up to perforation, whichever happened first. The impact response was evaluated in terms of evolution of the peak force, bending stiffness, visual damage inspection and optical transmission scanning (OTS) at critical stages as a function of number of impacts. Also, the damage degree (DD) was calculated to monitor the evolution of damage in the laminates. As expected, the impact response of the GFRP composites varied based on the presence of nano-clay and the applied impact energy. The modification of the resin with nano-clay introduced novel phenomena that changed the damage progression mechanism under repetitive impacts, which was verified by visual observation and optical transmission scanning. A better understanding of these phenomena (e.g. crack-bridging, tortuosity) and their contributions to enhancements in the impact behavior and modifications of the types of damage propagation can lead to better design of novel structural composites.

  19. Ballistic Impact Properties of Zr-Based Amorphous Alloy Composites Reinforced with Woven Continuous Fibers

    Science.gov (United States)

    Kim, Gyeong Su; Son, Chang-Young; Lee, Sang-Bok; Lee, Sang-Kwan; Song, Young Buem; Lee, Sunghak

    2012-03-01

    This study aims at investigating ballistic impact properties of Zr-based amorphous alloy (LM1 alloy) matrix composites reinforced with woven stainless steel or glass continuous fibers. The fiber-reinforced composites with excellent fiber/matrix interfaces were fabricated without pores and misinfiltration by liquid pressing process, and contained 35 to 41 vol pct of woven continuous fibers homogeneously distributed in the amorphous matrix. The woven-STS-continuous-fiber-reinforced composite consisted of the LM1 alloy layer of 1.0 mm in thickness in the upper region and the fiber-reinforced composite layer in the lower region. The hard LM1 alloy layer absorbed the ballistic impact energy by forming many cracks, and the fiber-reinforced composite layer interrupted the crack propagation and blocked the impact and traveling of the projectile, thereby resulting in the improvement of ballistic performance by about 20 pct over the LM1 alloy. According to the ballistic impact test data of the woven-glass-continuous-fiber-reinforced composite, glass fibers were preferentially fragmented to form a number of cracks, and the amorphous matrix accelerated the fragmentation of glass fibers and the initiation of cracks. Because of the absorption process of ballistic impact energy by forming very large amounts of cracks, fragments, and debris, the glass-fiber-reinforced composite showed better ballistic performance than the LM1 alloy.

  20. Impact Responses of Composite Cushioning System considering Critical Component with Simply Supported Beam Type

    Directory of Open Access Journals (Sweden)

    Fu-de Lu

    2014-04-01

    Full Text Available In some microelectronic products, one or several components can be idealized as simply supported beam type and viewed as vulnerable elements or critical component due to the fact that they are destroyed easily under impact loadings. The composite cushioning structure made of expanded polyethylene (EPE, and expanded polystyrene (EPS was utilized to protect the vulnerable elements against impact loadings during transportation. The vibration equations of composite cushioning system were deducted and virtual mass method was applied to predict impact behavior of critical component. Numerical results indicate that virtual mass method is appropriate for computing impact response of composite cushioning system with vulnerable element of simply supported beam type, which is affirmed by the fact that the impact responses of structure element in terms of velocity- and displacement-time curves are almost unchanged when virtual mass is smaller than a certain value. The results in this paper make it possible for installation of packaging optimization design.