Science.gov

Sample records for anagallis arvensis surface

  1. Participation of Photosynthesis in Floral Induction of the Long Day Plant Anagallis arvensis L. 1

    PubMed Central

    Quedado, Rosario M.; Friend, Douglas J.

    1978-01-01

    The saturating photon flux density (400 to 700 nanometers) for induction of flowering of the long day plant Anagallis arvensis L. was 1,900 micromoles per square meter per second (6,000 foot-candles) when an 8-hour daylength was extended to 24 hours by a single period of supplementary irradiation. The saturating photon flux density for photosynthetic CO2 uptake during the same single supplementary light period was lower, at about 1,000 to 650 micromoles per square meter per second (3,000 to 2,000 foot-candles). The per cent flowering and mean number of floral buds per plant were significantly reduced when the light extension treatment was given in CO2-free air, and glucose (10 kilograms per cubic meter in water) relieved this effect. Glucose solution also significantly increased flowering of plants given supplementary light treatment in atmospheric air under a photon flux density of 80 micromoles per square meter per second. Increasing the CO2 concentration to 1.27 grams per cubic meter of CO2 in air during the supplementary light period did not increase flowering. It is concluded that high photon flux densities promote flowering of Anagallis through both increased photosynthesis and the photomorphogenic action of high irradiance. PMID:16660610

  2. Effects of thermal power plant effluents on formation and senescence of reproductive parts of Anagallis arvensis L

    SciTech Connect

    Iqbal, M.; Khan, F.A.; Saquib, M.; Ahmad, Z.; Ghouse, A.K.M. )

    1989-04-01

    Oxides of sulfur, nitrogen and carbon and particulates are the major air pollutants emitted in huge amounts by the Thermal Power Plant Complex of Kasimpur (Aligarh, UP, India) running on 3192 MT of coal/day. These effluents significantly affect reproductive phase of Anagallis arvensis L. Samples of 10 plants each were randomly collected at monthly intervals at seedling to mature stage from 0.5, 2, 6, 12 and 20 km leeward from the power plant complex. Bud formation and flowering were delayed in the population thriving at 0.5 km from the pollution source. As a 2 month old stage, 60% of the population showed a decline in bud formation in the vicinity of the source compared to a heavy bud emergence in the whole population thriving 20 km away from it. Bud formation, flowering fruit set and seed set showed a correlation with multiple growth factors viz productivity, shoot length and distance from the source.

  3. Styryl-pyrones from Goniothalamus arvensis.

    PubMed

    Bermejo, A; Blázquez, M A; Rao, K S; Cortes, D

    1998-04-01

    Two novel styrl-pyrones, (+)-garvensintriol and (+)-etharvendiol, together with a known cytotoxic furano-furone, (+)-goniofufurone, have been isolated from the stem bark of Goniothalamus arvensis. A different relative configuration, cis-erythro-erythro for garvensintriol and cis-threo-erythro for etharvendiol, is established, and their absolute stereochemistry is discussed.

  4. [Phenotypic and phytochemical differences between Mentha arvensis L. and Mentha canadiensis L].

    PubMed

    Shelepova, O V; Voronkova, T V; Kondrat'eva, V V; Semenova, M V; Bidiukova, G F; Olekhnovich, L S

    2014-01-01

    A taxonomic study of anatomical, morphological, and phytochemical characteristics of Mentha arvensis L. and Mentha canadiensis L. using hierarchical cluster analysis has been conducted and the differences between the species studied have been revealed. The ratio between the lengths of the calyx tube and the calyx lobes, the number of secretory glands on the upper and lower surfaces of the leaf, and the composition of the essen- tial oil were shown to be the most appropriate parameters for classification.

  5. Metal Uptake Rates by Veronica anagallis aquatica at Pinal Creek near Globe, Arizona.

    NASA Astrophysics Data System (ADS)

    Robbins, E. A.; Conklin, M.; Harvey, J.; Corley, T.

    2002-12-01

    Pinal Creek, Globe, Arizona had elevated levels of dissolved manganese [Mn(II)] in the stream that has since been intercepted, due to recharge of contaminated ground water from numerous Cu mining operations. The focus of this study is to determine the distribution of metals on water speedwell and the rate of metal removal (Mn, Co, Ni, and Zn) from surface water by the aquatic plant `water speedwell', Veronica anagallis aquatica. Water speedwell grows in the central stream channel at Pinal Creek and is suspected to bio accumulate metals as well as provide surfaces for metal precipitation. Water speedwell was collected approximately monthly from Pinal Creek for one year. Roots and shoots were separated to determine external metal concentrations, and the plants were extracted using 0.03M EDTA and 0.03M ascorbic acid. Water speedwell accumulates substantial manganese in its root and shoot tissues with median values of 22,000 mg/kg dry root and 1,700 mg/kg dry shoot, respectively. The roots of water speedwell are capable of accumulating metals at concentrations well above sediment (7,000 mg/kg dry sediment) and surface water, with (1 mg/L) the majority of metals associated with the external plant surface. To determine metal uptake rates, a known mass of plants was placed in a container with artificial surface water that had been spiked with known metal concentrations and the change in metal concentration solution was monitored over time. Manganese, nickel, and cobalt followed similar trends of an initial rapid decrease in metal from solution followed by a slower uptake rate. As much as 50% of the manganese and nickel were removed from solution over a five-day period. Manganese was removed from surface water at an average rate of -0.0016 +/- 0.0007 (Log(mgMn)/hour). Removal of zinc from surface water was correlated with pH of the solution, which ranged from 6.0 to 7.5. The results indicate that water speedwell is effective in the removal of metals from surface water.

  6. Antioxidant and phytochemical analysis of Ranunculus arvensis L. extracts.

    PubMed

    Bhatti, Muhammad Zeeshan; Ali, Amjad; Ahmad, Ayaz; Saeed, Asma; Malik, Salman Akbar

    2015-06-30

    Ranunculus arvensis L. (R. arvensis) has long been used to treat a variety of medical conditions such as arthritis, asthma, hay fever, rheumatism, psoriasis, gut diseases and rheumatic pain. Here, we screened R. arvensis for antioxidant activity, phytochemical and high performance liquid chromatography (HPLC) analyses. The chloroform, chloroform:methanol, methanol, methanol:acetone, acetone, methanol:water and water extracts of R. arvensis were examined for DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging assay, hydrogen peroxide scavenging assay, phosphomolybdenum assay, reducing power assay, flavonoid content, phenolic content and high performance liquid chromatography analysis. Significant antioxidant activity was displayed by methanol extract (IC 50 34.71 ± 0.02) in DPPH free radical scavenging assay. Total flavonoids and phenolics ranged 0.96-6.0 mg/g of extract calculated as rutin equivalent and 0.48-1.43 mg/g of extract calculated as gallic acid equivalent respectively. Significant value of rutin and caffeic acid was observed via high performance liquid chromatography. These results showed that extracts of R. arvensis exhibited significant antioxidant activities. Moreover, R. arvensis is a rich source of rutin, flavonoids and phenolics.

  7. Evaluation of flavonoids and diverse antioxidant activities of Sonchus arvensis

    PubMed Central

    2012-01-01

    Background Sonchus arvensis is used in the treatment of various human aliments as a traditional medicine in Pakistan. In the study its various fractions are characterized for scavenging of diverse free radicals. Results Results of the present study revealed that various fractions of Sonchus arvensis significantly scavenged the free radicals (DPPH·, ABTS·+, ·OH, superoxide), however its methanolic fraction is more potent than other fractions. Significant correlation was found between DPPH·, ABTS·+, superoxide radical and total antioxidant activity with total flavonoids and phenolics contents. Phytochmical analysis revealed the presence kaempferol, quercetin, orientin, rutin, hyperoside, catechin and myricetin. Conclusion From the present data it is concluded that various fractions of Sonchus arvensis significantly scavenged the free radical, which might be due the presence of polyphenolic constituent. PMID:23107458

  8. Biological control studies on Convolvulus arvensis L. with fungal pathogens

    USDA-ARS?s Scientific Manuscript database

    Field bindweed (Convolvulus arvensis) is a perennial, noxious weed in Europe and in many agricultural areas of the world, including Turkey. Some pathogenic fungi were identified with potential to control bindweed and some of them could be used as mycoherbicide components. In the summers of 2008, 200...

  9. Selenium and its compounds in aquatic plant Veronica anagallis-aquatica.

    PubMed

    Kroflič, Ana; Germ, Mateja; Mechora, Špela; Stibilj, Vekoslava

    2016-05-01

    The uptake, distribution and determination of Se and its compounds in macrophyte Veronica anagallis-aquatica were investigated. V. anagallis-aquatica and sediments were sampled in years 2009-2011 and in 2013 in three Slovenian watercourses flowing through an agricultural area, where addition of Se in feedstuffs has been performed for about 25 years. Se content in sediments were up to 0.86 μg g(-1) and in whole plant varied from 0.186 to 1.535 μg g(-1), all on dry weight basis. Se content were measured also in different plant parts; highest content were found in roots and lowest in stems. Separation of extractable Se compounds was performed by ion exchange chromatography and for on-line detection inductively coupled plasma-mass spectrometry was used. The results showed that only approximately 24% of Se in the macrophyte was extracted using enzyme Protease XIV. Extractable Se in plant parts varied from 10.5% in roots to 29.6% in leaves. Identification of Se(IV) and Se(VI) was achieved but no Se-amino acids were detected even at highest Se content. According to our results, we assume that 25 years of Se addition in feedstuff shows minimal impact on Se content in the selected agricultural area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Crop-weed competition between sunflower (Helianthus annuus L.) and Convolvulus arvensis L. in substitutive experiments.

    PubMed

    Kazinczi, G; Takács, A; Horváth, J

    2006-01-01

    The main characteristics of a substitutive experiment is that the proportions of two species in the mixtures are varied while the overall density of the two species is maintained constant - a replacement series. In our experiments early competition between sunflower and field bindweed (Convolvulus arvensis) was studied in a replacement studies under glasshouse conditions. Pot experiments were set up with the following treatments: 1, sunflower 100% (6 plants pot(-1)); 2, sunflower 66.6% (4 plants pot(-1)) + C. arvensis 33.3% (2 plants pot(-1)); 3, sunflower 33.3% (2 plants pot(-1)) + C. arvensis 66.6% (4 plants pot(-1)); 4, C. arvensis 100% (6 plants pot(-1)). Sixty eight days after sowing dry weight of shoots and roots were measured and nitrogen (N), phosphorus (P) and potassium (K) content was also determined. Dry biomass production of sunflower was almost twice higher as compared to that of C. arvensis without interspecific competition. Dry weight of sunflower and C. arvensis shoots and roots for a plant continuously decreased by reducing their proportion in the mixtures. Higher biomass production of sunflower suggests, that its development is faster at the beginning of vegetation penod, therefore sunflower has better competitive ability in sunflower--C. arvensis mixtures in the early competition as compared to C. arvensis. Shoot:root ratio of plants did not change considerably in mixtures, but generally was ten times higher in sunflower plants, as compared to that of C. arvensis. Shoots generally contained macro elements at higher concentration as compared to those of roots. Total NPK content of sunflower was reduced by 53 and 82% for a pot, as its proportion decreased in the mixtures. More severe reduction in NPK content was observed in case of C. arvensis, which also proves stronger competitive ability of sunflower in the early vegetation.

  11. Aminocyclopyrachlor absorption, translocation and metabolism in field 1 bindweed (convolulus arvensis)

    USDA-ARS?s Scientific Manuscript database

    Field bindweed (Convolvulus arvensis L.) is extremely susceptible to aminocyclopyrachlor compared to other weed species. Laboratory studies were conducted to determine if absorption, translocation, and metabolism of aminocyclopyrachlor in field bindweed differs from other, less susceptible species....

  12. The reproductive strategies of the heterocarpic annual Calendula arvensis (Asteraceae)

    NASA Astrophysics Data System (ADS)

    Ruiz De Clavijo, E.

    2005-09-01

    Achene polymorphism and various aspects of the reproductive biology of the annual Calendula arvensis L. (Field marigold), were studied to determine the reproductive strategies of the plant. This species normally produces three types of achene: rostrate, cymbiform and annular. Rostrate and cymbiform achenes are larger and heavier than annular achenes, and are adapted to long-range dispersal (by epizoochory and anemochory, respectively). In contrast, annular achenes are smaller in size and weight, and are adapted to short-range dispersal. Achenes germinate over a broad range of temperatures (both in light and in darkness), exhibiting cymbiform achenes the highest germination percentages and annular achenes the lowest under all conditions tested. A fraction of the three types of achenes exhibit dormancy and presumably enter the soil seedbank. Achene types adapted for long-range dispersal (rostrate and cymbiform achenes) produce seedlings that are best able to emerge from deeper burial depths, and that are initially stronger and exhibit earlier flowering than the plants from the annular achenes (which are likely to disperse over shorter distances). These features, together with the fact that fruiting occurs even in the absence of pollinators (automatic geitonogamy), the different mechanisms for achene dispersal (zoochory, anemochory and myrmerochory), and the extended germination, flowering and fruiting periods, facilitate establishment and expansion of this species in unpredictable and disturbed habitats.

  13. Barriers to gene flow from oilseed rape (Brassica napus) into populations of Sinapis arvensis.

    PubMed

    Moyes, C L; Lilley, J M; Casais, C A; Cole, S G; Haeger, P D; Dale, P J

    2002-01-01

    One concern over growing herbicide-tolerant crops is that herbicide-tolerance genes may be transferred into the weeds they are designed to control. Brassica napus (oilseed rape) has a number of wild relatives that cause weed problems and the most widespread of these is Sinapis arvensis (charlock). Sinapis arvensis seed was collected from 102 populations across the UK, within and outside B. napus-growing areas. These populations were tested for sexual compatibility with B. napus and it was found that none of them hybridized readily in the glasshouse. In contrast to previous studies, we have found that hybrids can be formed naturally with S. arvensis as the maternal parent. Six diverse B. napus cultivars (Capricorn, Drakkar, Falcon, Galaxy, Hobson and Regent) were tested for their compatibility with S. arvensis but no cultivar hybridized readily in the glasshouse. We were unable to detect gene transfer from B. napus to S. arvensis in the field, confirming the extremely low probability of hybridization predicted from the glasshouse work.

  14. Mentha arvensis exhibit better adaptive characters in contrast to Mentha piperita when subjugated to sustained waterlogging stress.

    PubMed

    Phukan, Ujjal J; Mishra, Sonal; Timbre, Khilesh; Luqman, Suaib; Shukla, Rakesh Kumar

    2014-05-01

    Waterlogging is becoming a critical threat to plants growing in areas prone to flooding. Some plants adapt various morphological and biochemical alterations which are regulated transcriptionally to cope with the situation. A comparative study of waterlogging response in two different varieties of Mentha namely Mentha piperita and Mentha arvensis was performed. M. arvensis showed better response towards waterlogging in comparison to M. piperita. M. arvensis maintained a healthy posture by utilizing its carbohydrate content; also, it showed a flourished vegetative growth under waterlogged condition. Soluble protein, chlorophyll content, relative water content, and nitric oxide scavenging activity were comparatively more salient in M. arvensis during this hypoxia treatment. Lipid peroxidation was less in M. arvensis. M. arvensis also showed vigorous outgrowth of adventitious roots to assist waterlogging tolerance. To further investigate the possible gene transcripts involved in this response, we did cDNA subtraction of waterlogging treated M. piperita and M. arvensis seedlings. cDNA subtraction has identified thirty seven novel putative Expressed Sequence Tags which were further classified functionally. Functional classification revealed that maximum percentage of proteins belonged to hypothetical proteins followed by proteins involved in biosynthesis. Some of the identified ESTs were further quantified for their induced expression in M. arvensis in comparison to M. piperita through quantitative real-time PCR.

  15. Anticandidal, antibacterial, cytotoxic and antioxidant activities of Calendula arvensis flowers.

    PubMed

    Abudunia, A-M; Marmouzi, I; Faouzi, M E A; Ramli, Y; Taoufik, J; El Madani, N; Essassi, E M; Salama, A; Khedid, K; Ansar, M; Ibrahimi, A

    2017-03-01

    Calendula arvensis (CA) is one of the important plants used in traditional medicine in Morocco, due to its interesting chemical composition. The present study aimed to determine the anticandidal, antioxidant and antibacterial activities, and the effects of extracts of CA flowers on the growth of myeloid cancer cells. Also, to characterize the chemical composition of the plant. Flowers of CA were collected based on ethnopharmacological information from the villages around the region Rabat-Khemisset, Moroccco. The hexane and methanol extracts were obtained by soxhlet extraction, while aqueous extracts was obtained by maceration in cold water. CA extracts were assessed for antioxidant activity using four different methods (DPPH, FRAP, TEAC, β-carotene bleaching test). Furthermore, the phenolic and flavonoid contents were measured, also the antimicrobial activity has been evaluated by the well diffusion method using several bacterial and fungal strains. Finally, extracts cytotoxicity was assessed using MTT test. Phytochemical quantification of the methanolic and aqueous extracts revealed that they were rich with flavonoid and phenolic content and were found to possess considerable antioxidant activities. MIC values of methanolic extracts were 12.5-25μg/mL. While MIC values of hexanolic extracts were between 6.25-12.5μg/mL and were bacteriostatic for all bacteria while methanolic and aqueous extracts were bactericidal. In addition, the extracts exhibited no activity on Candida species except the methanolic extract, which showed antifungal activity onCandida tropicalis 1 and Candida famata 1. The methanolic and aqueous extracts also exhibited antimyeloid cancer activity (IC50 of 31μg/mL). In our study, we conclude that the methanolic and aqueous extracts were a promising source of antioxidant, antimicrobial and cytotoxic agents.

  16. Phytoremediation of lead-contaminated soil by Sinapis arvensis and Rapistrum rugosum.

    PubMed

    Saghi, Abolghasem; Rashed Mohassel, Mohammad Hassan; Parsa, Mehdi; Hammami, Hossein

    2016-01-01

    Nowadays, public concern relating to ecological deleterious effects of heavy metals is on the rise. To evaluate the potential of Rapistrum rugosum and Sinapis arvensis in lead- contaminate phytoremediate, a pot culture experiment was conducted. The pots were filled by soil treated with different rates of leadoxide (PbO) including 0 (control), 100, 200, 300, 400, and 500 mg Pb per 1 kg soil. Germinated seeds were sown. Surprisingly, with increasing concentration of Pb, dry weight of R. rugosum and S. arvensis did not decrease significantly. In both of species, the concentration of Pb was higher in roots than shoots. In general, S.arvensis was absorbed more Pb compared to R. rugosum. The results revealed high potential of R. rugosum and S. arvensis in withdrawing Pb from contaminated soil. For both species, a positive linear relation was observed between Pb concentration in soil and roots. However, linear relationship was not observed between Pb concentration in the soil and shoots. Although both species test had low ability in translocation Pb from roots to shoots but they showed high ability in uptake soil Pb by roots. Apparently, these plants are proper species for using in phytoremediation technology.

  17. Determination of the genotoxic effects of Convolvulus arvensis extracts on corn (Zea mays L.) seeds.

    PubMed

    Sunar, Serap; Yildirim, Nalan; Aksakal, Ozkan; Agar, Guleray

    2013-06-01

    In this research, the methanolic extracts of Convolvulus arvensis were tested for genotoxic and inhibitor activity on the total soluble protein content and the genomic template stability against corn Zea mays L. seed. The methanol extracts of leaf, stem and root of C. arvensis were diluted to 50, 75 and 100 μl concentrations and applied to corn seed. The total soluble protein and genomic template stability results were compared with the control. The results showed that especially 100 μl extracts of diluted leaf, stem and root had a strong inhibitory activity on the genomic template stability. The changes occurred in random amplification of polymorphic DNA (RAPD) profiles of C. arvensis extract treatment included variation in band intensity, loss of bands and appearance of new bands compared with control. Also, the results obtained from this study revealed that the increase in the concentrations of C. arvensis extract increased the total soluble protein content in maize. The results suggested that RAPD analysis and total protein analysis could be applied as a suitable biomarker assay for the detection of genotoxic effects of plant allelochemicals.

  18. Covalent immobilization of β-1,4-glucosidase from Agaricus arvensis onto functionalized silicon oxide nanoparticles.

    PubMed

    Singh, Raushan Kumar; Zhang, Ye-Wang; Nguyen, Ngoc-Phuong-Thao; Jeya, Marimuthu; Lee, Jung-Kul

    2011-01-01

    An efficient β-1,4-glucosidase (BGL) secreting strain, Agaricus arvensis, was isolated and identified. The relative molecular weight of the purified A. arvensis BGL was 98 kDa, as determined by sodium dodecylsulfate polyacrylamide gel electrophoresis, or 780 kDa by size exclusion chromatography, indicating that the enzyme is an octamer. Using a crude enzyme preparation, A. arvensis BGL was covalently immobilized onto functionalized silicon oxide nanoparticles with an immobilization efficiency of 158%. The apparent V (max) (k (cat)) values of free and immobilized BGL under standard assay conditions were 3,028 U mg protein(-1) (4,945 s(-1)) and 3,347 U mg protein(-1) (5,466 s(-1)), respectively. The immobilized BGL showed a higher optimum temperature and improved thermostability as compared to the free enzyme. The half-life at 65 °C showed a 288-fold improvement over the free BGL. After 25 cycles, the immobilized enzyme still retained 95% of the original activity, thus demonstrating its prospects for commercial applications. High specific activity, high immobilization efficiency, improved stability, and reusability of A. arvensis BGL make this enzyme of potential interest in a number of industrial applications.

  19. Genetic elaborations of glandular and non-glandular trichomes in Mentha arvensis genotypes: assessing genotypic and phenotypic correlations along with gene expressions.

    PubMed

    Mishra, Anand; Lal, R K; Chanotiya, C S; Dhawan, Sunita Singh

    2017-03-01

    Mentha arvensis (corn mint) is well known for the production of menthol, a widely used commodity in pharma and flavoring industries and provides natural fragrances and products. Glandular trichomes are specialized hairs found on the aerial surface of vascular plants species producing specific secondary metabolite chemistry. Correlations were established among trichomes, oil yield, and major secondary metabolites. Nine improved, elite cultivars representing different M. arvensis genotypes were used for analysis. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were estimated; results indicated the presence of considerable amount of genetic variability, thereby emphasizing wide scope of selection. Positive and significant associations were found among glandular trichomes, oil yield, essential oil constituents, and leaf morphology itself, whereas morphological parameters of leaf show positive and negative correlations to average number of trichome and essential oil constituents. Average number of glandular, non-glandular trichomes, their ratios, menthol content, and trichome number showed a good heritability. Trichomes were studied microscopically in leaf parts in all varieties for analyzing their distribution pattern. The trichome number variations showed significant correlation throughout the genotypes with essential oil yield and monoterpenoid constituents. Differential changes were analyzed for Glutathione S-transferases, Glutathione reductase, Malondialdehyde, phenolics, and chlorophyll content. Gene expressions were analyzed for biosynthesis genes and selected transcription factors TRANSPARENT TESTA GLABRA 1 (TTG1), ENOLASE 1, GLABRA 3, GTL 1, NUCLEAR TRANSCRIPTION FACTOR Y SUBUNIT B-6, WRKY transcription factor 22, putative WRKY 33, WRKY 17, WRKY 1, and WRKY 65-like for harnessing their relation with trichome development in M. arvensis genotypes.

  20. Effect of Sulfate on Selenium Uptake And Chemical Speciation in Convolvulus Arvensis L

    SciTech Connect

    Cruz-Jimenez, G.; Peralta-Video, J.R.; Rosa, G.de la; Meitzner, G.; Parson, J.G.; Gardea-Torresdey, J.L.

    2007-08-08

    Hydroponic experiments were performed to study several aspects of Se uptake by C. arvensis plants. Ten day old seedlings were exposed for eight days to different combinations of selenate (SeO{sub 4}{sup 2-}), sulfate (SO{sub 4}{sup 2-}), and selenite (SeO{sub 3}{sup 2-}). The results showed that in C. arvensis, SO{sub 4}{sup 2-} had a negative effect (P < 0.05) on SeO{sub 4}{sup 2-} uptake. However, a positive interaction produced a significant increase in SO{sub 4}{sup 2-} uptake when SeO{sub 4}{sup 2-} was at high concentration in the media. X-ray absorption spectroscopy studies showed that C. arvensis plants converted more than 70% of the supplied SeO{sub 3}{sup 2-} into organoselenium compounds. However, only approximately 50% of the supplied SeO{sub 4}{sup 2-} was converted into organoselenium species while the residual 50% remained in the inorganic form. Analysis using LC-XANES fittings confirmed that the S metabolic pathway was affected by the presence of Se. The main Se compounds that resembled those Se species identified in C. arvensis were Se-cystine, Se-cysteine, SeO{sub 3}{sup 2-}, and SeO{sub 4}{sup 2-}, whereas for S the main compounds were cysteine, cystine, oxidized glutathione, reduced glutathione, and SO{sub 4}{sup 2-}. The results of these studies indicated that C. arvensis could be considered as a possible option for the restoration of soil moderately contaminated with selenium even in the presence of sulfate.

  1. Preservation of pears in water in the presence of Sinapis arvensis seeds: a Greek tradition.

    PubMed

    Papatsaroucha, Eleni; Pavlidou, Sofia; Hatzikamari, Magdalini; Lazaridou, Athina; Torriani, Sandra; Gerasopoulos, Dimitris; Tzanetaki, Evanthia Litopoulou

    2012-10-15

    In this research, the microbiological and physicochemical changes during preservation of pears in water in the presence of Sinapis arvensis seeds (PWS FL) according to the traditional Greek home food manufacture were studied. Pears preserved in water served as control (PW FL). The growth of lactic acid bacteria (LAB) coming from the pear surface was enhanced in the presence of Sinapis seeds, while Enterobacteriaceae and Gram-negative bacteria declined coincidently with the lower (P<0.05) pH of the PWS FL. LAB predominated over the other microbial groups in the fermentation liquids (FLs) of both systems. All the 49 LAB isolates from one fermentation experiment were identified as Leuconostoc mesenteroides subsp. cremoris by the SDS-PAGE of whole-cell proteins, while RAPD-PCR fingerprinting and partial 16S rRNA sequence determination of selected isolates did not discriminate them at the subspecies level. Fruit preserved in PWS FL had higher titratable or volatile acidity, phenolic compounds or antioxidant capacity as well as lower pH and firmness than the control fruit. All physicochemical parameters of the FLs increased except of the pH which decreased. Coincidently with higher population of LAB in PWS FL the levels of citric, lactic and acetic acid were higher than in control. Oxalic acid and related unknown substances were found at higher levels in PWS FL than the control and may be the agent(s) enhancing the growth of LAB and/or contributing partially to the decline of Enterobacteriaceae. The organoleptic test showed that fruit preserved in PWS FL had better overall acceptance than the control, and that it retained most of the positive traits. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Enhanced phytoremediation of cadmium polluted water through two aquatic plants Veronica anagallis-aquatica and Epilobium laxum.

    PubMed

    Ahmad, Ayaz; Hadi, Fazal; Ali, Nasir; Jan, Amin Ullah

    2016-09-01

    Toxic metal-contaminated water is a major threat to sustainable agriculture and environment. Plants have the natural ability to absorb and concentrate essential elements in its tissues from water solution, and this ability of plants can be exploited to remove heavy/toxic metals from the contaminated water. For this purpose, two plants Veronica anagallis-aquatica and Epilobium laxum were hydroponically studied. The effect of different fertilizers (NPK) and plant growth regulators (GA3 and IAA) were evaluated on growth, biomass, free proline, phenolics, and chlorophyll contents, and their role in Cd phytoaccumulation was investigated. Results showed that in both plants, fertilizer addition to media (treatment T4) produced the highest significant increase in growth, biomass (fresh and dry), cadmium concentration, proline, phenolics, and chlorophyll concentrations. The significant effect of GA3 in combination with NPK foliar spray (treatment T12) was observed on most of the growth parameters, Cd concentration, and proline and phenolic contents of the plants. The free proline and total phenolics showed positive correlation with cadmium concentration within plant tissues. Proline showed significantly positive correlation with phenolic contents of root and shoot. Veronica plant demonstrated the hyperaccumulator potential for cadmium as bioconcentration factor (BCF >1) which was much higher than 1, while Epilobium plant showed non-hyperaccumulator potential. It is recommended for further study to investigate the role of Veronica plant for other metals and to study the role of phenolics and proline contents in heavy metal phytoextraction by various plant species.

  3. A rare chemical burn due to Ranunculus arvensis: three case reports.

    PubMed

    Kocak, Abdullah O; Saritemur, Murat; Atac, Kenan; Guclu, Sibel; Ozlu, Ibrahim

    2016-01-01

    Ranunculus arvensis, a plant that is a member of Ranunculaceae family, generally used for local treatment of joint pain, muscle pain, burns, lacerations, edema, abscess drainage, hemorrhoids, and warts among the population. In this case report, we presented three patients who developed chemical skin burns after using R. arvensis plant locally for knee pain. The destructive effect of the plant has been reported previously to be more in fresh plants and less in dried plants. Although protoanemonin, which is considered as the main toxic substance, was reported to be absent in dried or boiled plants, the plant was boiled, cooled, and wrapped over the region with pain in our cases. Therefore, we thought that protoanemonin may be considered to be heat resistant. Also, the burn management proceeded up to surgery by using the flap technique in one of our patients in contrast to the cases found in published reports who were treated by antibiotics and dressings.

  4. Vegetative reproduction and chemical control with post-emergent herbicides of field bindweed (Convolvulus arvensis L.).

    PubMed

    Gyenes, V; Béres, I; Lehoczky, E; Kazinczi, G; Nyári, A

    2005-01-01

    It is clearly seen from data that roots of Convolvulus arvensis L. have more and less intensive regenerative period during growing season. The more intensive period is in autumn, because in that time roots culminate nutrients, carbohydrate as starch and sugar. The less intensive regenerative or shoot-growing period is in spring, called "late spring bud dormancy". Experiments were conducted to get more information and further details about the regenerative capacity of roots close to and far from the collar of Convolvulus arvensis L. Root segments closer to collar have an intensive regenerative capacity than those ones further to collar. By data of Bakke et al. (1939) is well known, roots exhumed from deep soil layers are able to create shoots with low intensity. So finally we can exclaim that regenerative capacity is decreasing further to collar. Using mechanical weed control it is sufficient to till the upper layer of soil, but many times. Chemical treatments are most effective in the integrated weed control. It is clearly seen that auxin-type herbicide such as 2,4-D, fluroxipir, MCPA. dicamba give the best result. They gave 95% weed control effect used them separately or in combination with other herbicides. Combination of Banvel 480 S (dicamba) and Logran 75 WG (triasulfuron) introduced 95% weed control effect. Only one time got absolutely 100% weed control effect, in the case of Glyphosate active substance. Caused total plant destruction. Excellent result was given with the application of Pledge 50WP (flumioxazin). Herbicides mentioned above are absolutely allowed to take an important and significant part in chemical plant protection against Convolvulus arvensis L. Other herbicides like Granstar 75DF (tribenuron-methyl), Basis 75DF (rimsulfuron + tifensulfuron-methyl) and Huszár (jodosulfuron-methyl-sodium + mefenpir-diethyl) are not so effective against Convolvulus arvensis L., as compared to the previous ones.

  5. Phytocontact dermatitis due to Ranunculus arvensis mimicking burn injury: report of three cases and literature review

    PubMed Central

    2011-01-01

    Ranunculus arvensis (corn buttercup) is a plant species of the genus Ranunculus that is frequently used in the Far East to treat rheumatic diseases and several dermatological disorders. In Turkey, the plant is seen in the eastern and southeastern Anatolian highlands, which are underdeveloped areas of the country. Herein, we report three patients who used Ranunculus arvensis for the treatment of arthralgia and osteoarthritis. A distinctive phytodermatitis developed on the right thumb in one patient (48-year-old male), on the anterior aspect of both knees in another patient (70-year-old female) and all around both knees in a third (59-year-old female). The patients were treated with topical antibiotics and daily wound dressing, and none of them experienced any complications. Ranunculus arvensis was confirmed as the cause of the phytodermatitis in the three cases. Poultices of plants applied to the skin demonstrate beneficial effects on many dermatological and rheumatic diseases; however, they have several adverse effects that should not be ignored. In this study, we also present a review of 25 cases reported in the literature. PMID:21408003

  6. Seed Coat Microsculpturing Is Related to Genomic Components in Wild Brassica juncea and Sinapis arvensis

    PubMed Central

    Kang, Ding-ming; Ma, Ke-ping

    2013-01-01

    It has been reported that wild Brassica and related species are widely distributed across Xinjiang, China, and there has been an argument for species identification. Seed coat microsculpturing (SCM) is known to be an excellent character for taxonomic and evolutionary studies. By identifying collections from Xinjiang, China, and combining SCM pattern, flow cytometry, and genome-specific DNA markers as well as sexual compatibility with known species, this study aimed to detect potential relationships between SCM and genomic types in wild Brassica and related species. Three wild collections were found to be tetraploid with a SCM reticulate pattern similar to B. juncea, and containing A and B genome-specific loci, indicating relatively high sexual compatibility with B. juncea. The others were diploid, carrying S-genome-specific DNA markers, and having relatively high sexual compatibility with Sinapis arvensis. Moreover, their SCM was in a rugose pattern similar to that of S. arvensis. It was suggested that SCM, as a morphological characteristic, can reflect genomic type, and be used to distinguish B-genome species such as B. juncea from the related S. arvensis. The relationship between SCM and genomic type can support taxonomic studies of the wild Brassica species and related species. PMID:24386242

  7. Phytocontact dermatitis due to Ranunculus arvensis mimicking burn injury: report of three cases and literature review.

    PubMed

    Akbulut, Sami; Semur, Heybet; Kose, Ozkan; Ozhasenekler, Ayhan; Celiktas, Mustafa; Basbug, Murat; Yagmur, Yusuf

    2011-02-21

    Ranunculus arvensis (corn buttercup) is a plant species of the genus Ranunculus that is frequently used in the Far East to treat rheumatic diseases and several dermatological disorders. In Turkey, the plant is seen in the eastern and southeastern Anatolian highlands, which are underdeveloped areas of the country. Herein, we report three patients who used Ranunculus arvensis for the treatment of arthralgia and osteoarthritis. A distinctive phytodermatitis developed on the right thumb in one patient (48-year-old male), on the anterior aspect of both knees in another patient (70-year-old female) and all around both knees in a third (59-year-old female). The patients were treated with topical antibiotics and daily wound dressing, and none of them experienced any complications. Ranunculus arvensis was confirmed as the cause of the phytodermatitis in the three cases. Poultices of plants applied to the skin demonstrate beneficial effects on many dermatological and rheumatic diseases; however, they have several adverse effects that should not be ignored. In this study, we also present a review of 25 cases reported in the literature.

  8. Antimicrobial, antitumor and brine shrimp lethality assay of Ranunculus arvensis L. extracts.

    PubMed

    Bhatti, Muhammad Zeeshan; Ali, Amjad; Saeed, Asma; Saeed, Ahmad; Malik, Salman Akbar

    2015-05-01

    To investigate the antitumor activity, brine shrimp lethality assay, antibacterial and antifungal activity of Methanol Extract (ME), Water Extract (WE), Acetone Extract (AE), Chloroform Extract (CE), Methanol-Water Extract (MWE), Methanol-Acetone Extract (MAE), Methanol-Chloroform Extract (MCE) of Ranunculus arvensis (L.). Antitumor activity was evaluated with Agrobacterium tumefaciens (At10) induced potato disc assay. Cytotoxicity was evaluated with brine shrimp lethality assay. Antibacterial activity was evaluated with six bacterial strains including Escherichia coli, Enterobacter aerogenes, Bordetella bronchiseptica, Klebsiella pneumoniae, Micrococcus luteus and Streptococcus anginosus and antifungal screening was done against five fungal strains including Aspergillus niger, A. flavus, A. fumigates, Fusarium solani and Mucor species by using disc diffusion method. Best antitumor activity was obtained with ME and WE, having highest IC50 values 20.27 ± 1.62 and 93.01 ± 1.33μg/disc. Brine shrimp lethality assay showed LC50 values of AE, MAE and ME were obtained as 384.66 ± 9.42μg/ml, 724.11 ± 8.01μg/ml and 978.7 ±8.01 μg/ml respectively. WE of R. arvensis revealed weak antimicrobial result against the tested microorganisms. On the other hand, the antifungal activity of the plant extracts was found to be insignificant. These findings demonstrate that extracts of R. arvensis possesses significant antitumor activity. Further extensive study is necessary to assess the therapeutic potential of the plant.

  9. Conspecific flowers of Sinapis arvensis are stronger competitors for pollinators than those of the invasive weed Bunias orientalis.

    PubMed

    Hochkirch, Axel; Mertes, Tamara; Rautenberg, Julia

    2012-03-01

    Biological invasions can affect the structure and function of ecosystems and threaten native plant species. Since most weeds rely on mutualistic relationships in their new environment, they may act as new competitors for pollinators. Pollinator competition is likely to be density dependent, but it is often difficult to disentangle competition caused by flower quality from effects caused by flower quantity. In order to test the effects of the presence and number of flowers of the invasive weed Bunias orientalis on the insect visitation rates in a native species (Sinapis arvensis), we performed two replacement experiments using plants with standardised flower numbers. The visitation rates in S. arvensis were significantly higher than in B. orientalis and the number of insect visits dropped significantly with increasing density of S. arvensis flowers. These results suggest that intraspecific competition among flowers of S. arvensis is stronger than the competitive effect of alien flowers. As flowers of B. orientalis do not seem to distract visitors from S. arvensis, it is unlikely that pollinator competition between these two plant species plays a crucial role. However, it cannot be excluded that mass blossom stands of B. orientalis may distract flower visitors from nativespecies.

  10. Conspecific flowers of Sinapis arvensis are stronger competitors for pollinators than those of the invasive weed Bunias orientalis

    NASA Astrophysics Data System (ADS)

    Hochkirch, Axel; Mertes, Tamara; Rautenberg, Julia

    2012-03-01

    Biological invasions can affect the structure and function of ecosystems and threaten native plant species. Since most weeds rely on mutualistic relationships in their new environment, they may act as new competitors for pollinators. Pollinator competition is likely to be density dependent, but it is often difficult to disentangle competition caused by flower quality from effects caused by flower quantity. In order to test the effects of the presence and number of flowers of the invasive weed Bunias orientalis on the insect visitation rates in a native species ( Sinapis arvensis), we performed two replacement experiments using plants with standardised flower numbers. The visitation rates in S. arvensis were significantly higher than in B. orientalis and the number of insect visits dropped significantly with increasing density of S. arvensis flowers. These results suggest that intraspecific competition among flowers of S. arvensis is stronger than the competitive effect of alien flowers. As flowers of B. orientalis do not seem to distract visitors from S. arvensis, it is unlikely that pollinator competition between these two plant species plays a crucial role. However, it cannot be excluded that mass blossom stands of B. orientalis may distract flower visitors from native species.

  11. Alternethanoxins A and B, polycyclic ethanones produced by Alternaria sonchi , potential mycoherbicides for Sonchus arvensis biocontrol.

    PubMed

    Evidente, Antonio; Punzo, Biancavaleria; Andolfi, Anna; Berestetskiy, Alexander; Motta, Andrea

    2009-08-12

    Alternaria sonchi is a fungal pathogen isolated from Sonchus arvensis and proposed as a biocontrol agent of this noxious perennial weed. Different phytotoxic metabolites were isolated from solid culture of the fungus. Two new polycyclic ethanones, named alternethanoxins A and B, were characterized using essentially spectroscopic and chemical methods. Tested by leaf disk-puncture assay on the fungal host plant and a number of nonhost plants, alternethanoxins A and B were shown to be phytotoxic, whereas they did not possess antimicrobial activity tested at 100 microg/disk. Hence, alternethanoxins A and B have potential as nonselective natural herbicides. Some structure-activity relationship observations were also made.

  12. Nesting biology, morphological remarks, and description of the mature larva of Mellinus arvensis obscurus (Hymenoptera: Crabronidae) in Nepal

    SciTech Connect

    Boesi, R.; Polidori, C.; Andrietti, F.; Gayubo, S.F.; Tormos, J.; Asis, J.D.

    2007-03-15

    Recently re-named as a sub-species of Mellinus arvensis, Mellinus arvensis obscurus Handlirsch 1888 was investigated ecologically and morphologically in Nepal, in order to underline the most important differences with the well known M. arvensis arvensis. Mellinus arvensis obscurus females nested in clumped aggregations on inclined plains at high altitudes, both on sunny bare soil and on a shaded grassy one. Beginning of monsoon season probably interfered with wasp activity, and females performed few provisioning flights during the day. Prey consisted of a broad range of Diptera, except for one case of a spider. Many females were observed not provisioning a nest but floating on the nesting site, and many intraspecific interactions suggested a high degree of usurpation attempts. At least one species of flies and two of ants probably acted as natural enemies of the wasp. Morphological observations on females showed that the Nepal population shares more similarities (shape of tergite I, body punctation) with the European populations than with the closer Japanese population; melanization is strong, according to west-east and altitudinal cline. The mature larva of M. arvensis obscurus Handlirsch is described, illustrated, and compared with the other mature larva of the genus. The differences between both larvae mainly lie in the presence/absence, and number or differentiation of integumental structures. We conclude that morphological traits are more important than ecological and behavioral ones in distinguishing M. arvensis obscurus from M. arvensis arvensis. (author) [Spanish] En el presente articulo se aportan los resultados y conclusiones de un estudio, llevado a cabo en Nepal, en el que se abordaron aspectos ecologicos, comportamentales y morfologicos (tanto del ultimo estado de la fase larvaria como del adulto) de Mellinus arvensis obscurus Handlirsch 1888. El principal objetivo del estudio radicaba en mostrar las principales diferencias que separan a esta

  13. Corn mint (Mentha arvensis) extract diminishes acute Chlamydia pneumoniae infection in vitro and in vivo.

    PubMed

    Salin, Olli; Törmäkangas, Liisa; Leinonen, Maija; Saario, Elise; Hagström, Marja; Ketola, Raimo A; Saikku, Pekka; Vuorela, Heikki; Vuorela, Pia M

    2011-12-28

    Corn mint ( Mentha arvensis ) provides a good source of natural phenols such as flavone glycosides and caffeic acid derivatives, which may have prophylactic properties against inflammations. This study investigated whether corn mint extract would be beneficial against a universal respiratory tract pathogen, Chlamydia pneumoniae , infection. The extract inhibited the growth of C. pneumoniae CWL-029 in vitro in a dose-dependent manner. The inhibition was confirmed against a clinical isolate K7. The phenolic composition of the extract was analyzed by UPLC-ESI/Q-TOF/MS, the main components being linarin and rosmarinic acid. These compounds were active in vitro against C. pneumoniae. Linarin completely inhibited the growth at 100 μM. Inbred C57BL/6J mice were inoculated with C. pneumoniae K7. M. arvensis extract was given intraperitoneally once daily for 3 days prior to inoculation and continued for 10 days postinfection. The extract was able to diminish the inflammatory parameters related to C. pneumoniae infection and significantly (p = 0.019) lowered the number of C. pneumoniae genome equivalents detected by PCR at biologically relevant amounts.

  14. Transfer of Dicamba Tolerance from Sinapis arvensis to Brassica napus via Embryo Rescue and Recurrent Backcross Breeding.

    PubMed

    Jugulam, M; Ziauddin, Asma; So, Kenny K Y; Chen, Shu; Hall, J Christopher

    2015-01-01

    Auxinic herbicides (e.g. dicamba) are extensively used in agriculture to selectively control broadleaf weeds. Although cultivated species of Brassicaceae (e.g. Canola) are susceptible to auxinic herbicides, some biotypes of Sinapis arvensis (wild mustard) were found dicamba resistant in Canada. In this research, dicamba tolerance from wild mustard was introgressed into canola through embryo rescue followed by conventional breeding. Intergeneric hybrids between S. arvensis (2n = 18) and B. napus (2n = 38) were produced through embryo rescue. Embryo formation and hybrid plant regeneration was achieved. Transfer of dicamba tolerance from S. arvensis into the hybrid plants was determined by molecular analysis and at the whole plant level. Dicamba tolerance was introgressed into B. napus by backcrossing for seven generations. Homozygous dicamba-tolerant B. napus lines were identified. The ploidy of the hybrid progeny was assessed by flow cytometry. Finally, introgression of the piece of DNA possibly containing the dicamba tolerance gene into B. napus was confirmed using florescence in situ hybridization (FISH). This research demonstrates for the first time stable introgression of dicamba tolerance from S. arvensis into B. napus via in vitro embryo rescue followed by repeated backcross breeding. Creation of dicamba-tolerant B. napus varieties by this approach may have potential to provide options to growers to choose a desirable herbicide-tolerant technology. Furthermore, adoption of such technology facilitates effective weed control, less tillage, and possibly minimize evolution of herbicide resistant weeds.

  15. Seed dormancy is modulated in recently evolved chlorsulfuron-resistant Turkish biotypes of wild mustard (sinapis arvensis)

    USDA-ARS?s Scientific Manuscript database

    Biotypes of the broad-leaved wild mustard (Sinapis arvensis L.) found in wheat fields of the Aegean and Marmara regions of Turkey, were characterized and shown to have developed resistance to sulfonylurea (chlorsulfuron), an inhibitor of acetolactate synthase (ALS). DNA sequence analysis of the ALS...

  16. Ozone exposure of a weed community produces adaptive changes in seed populations of Spergula arvensis.

    PubMed

    Landesmann, Jennifer B; Gundel, Pedro E; Martínez-Ghersa, M Alejandra; Ghersa, Claudio M

    2013-01-01

    Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

  17. Ozone Exposure of a Weed Community Produces Adaptive Changes in Seed Populations of Spergula arvensis

    PubMed Central

    Landesmann, Jennifer B.; Gundel, Pedro E.; Martínez-Ghersa, M. Alejandra; Ghersa, Claudio M.

    2013-01-01

    Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production. PMID:24086640

  18. Genome-specific SCAR markers help solve taxonomy issues: a case study with Sinapis arvensis (Brassiceae, Brassicaceae).

    PubMed

    Pankin, Artem A; Khavkin, Emil E

    2011-03-01

    Traditional taxonomy and nomenclature of Brassiceae (Brassicaceae) species do not reflect their phylogeny. Revision of the species and generic limits supported by extensive molecular data seems crucial. Genome-specific polymorphisms extracted from non-coding and coding sequences were used to develop 14 sequence characterized amplified region (SCAR) markers specific for the Brassica B genome. These SCARs were verified against 77 accessions of six U-triangle Brassica species and used to screen 23 accessions of seven wild Brassiceae species to test for their cross-species amplification. SCARs were found in all B-genome Brassica species and also in Sinapis arvensis. SCAR markers can be employed for discerning B-genome chromosomes in Brassica species and S. arvensis to reliably identify B-genome species and their natural hybrids. The combined molecular evidence supports the suggestion to revise the generic limits of Brassica and Sinapis.

  19. Effect of plant density on competitiveness of Brassica napus, Sinapis alba and S. arvensis under water stress conditions.

    PubMed

    Maataoui, A; Talouizte, A; Benbella, M; Bouhache, M

    2005-01-01

    Under Mediterranean climate, oilseed rape is subjected especially to the competition of weeds with respect to water. Herbicides registered for this crop do not effectively control species of the same family, in particular Sinapis alba and Sinapis arvensis. Moreover, there are no results of the effect of plant density on the competitiveness of these species. The purpose of this experiment was to determine if the competitiveness of the species varies according to the total density. The experiment was carried out in pots under greenhouse conditions, according to a replacement series method. Plant densities tested were 2, 4 and 8 plants per pot. The results of the replacement series diagram and those of relative crowding coefficients showed that Brassica napus was the most competitive, whatever the density is. This classification is explained primarily by leaf area. Indeed, the intraspecific competition due to B. napus has affected more its leaf area than the interspecific competition. Conversely, the intraspecific competition due to S. arvensis has less affected its leaf area than the interspecific competition. Regarding S. alba, the intraspecific competition effect was less severe than the interspecific competition effect due to B. napus and more severe than the interspecific competition effect due to S. arvensis on S. alba

  20. Validation of endogenous reference genes in Buglossoides arvensis for normalizing RT-qPCR-based gene expression data.

    PubMed

    Gadkar, Vijay J; Filion, Martin

    2015-01-01

    Selection of a stably expressed reference gene (RG) is an important step for generating reliable and reproducible quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) gene expression data. We, in this study, have sought to validate RGs for Buglossoides arvensis, a high nutraceutical value plant whose refined seed oil is entering the market under the commercial trade name Ahiflower™. This weed plant has received attention for its natural ability to significantly accumulate the poly-unsaturated fatty acid (PUFA) stearidonic acid (SDA, C18:4n-3) in its seeds, which is uncommon for most plant species. Ten candidate RGs (β-Act, 18S rRNA, EF-1a, α-Tub, UBQ, α-actin, CAC, PP2a, RUBISCO, GAPDH) were isolated from B. arvensis and TaqMan™ compliant primers/probes were designed for RT-qPCR analysis. Abundance of these gene transcripts was analyzed across different tissues and growth regimes. Two of the most widely used algorithms, geNorm and NormFinder, showed variation in expression levels of these RGs. However, combinatorial analysis of the results clearly identified CAC and α-actin as the most stable and unstable RG candidates, respectively. This study has for the first time identified and validated RGs in the non-model system B. arvensis, a weed plant projected to become an important yet sustainable source of dietary omega-3 PUFA.

  1. The Effect of Convolvulus arvensis Dried Extract as a Potential Antioxidant in Food Models

    PubMed Central

    Mohd Azman, Nurul Aini; Gallego, Maria Gabriela; Juliá, Luis; Fajari, Lluis; Almajano, MaríaPilar

    2015-01-01

    In this study, the antioxidant activity of the Convolvulus arvensis Linn (CA) ethanol extract has been evaluated by different ways. The antioxidant activity of the extract assessed by 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation, the oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP) was 1.62 mmol Trolox equivalents (TE)/g DW, 1.71 mmol TE/g DW and 2.11 mmol TE/g DW, respectively. CA ethanol extract exhibited scavenging activity against the methoxy radical initiated by the Fenton reaction and measured by Electron Paramagnetic Resonance (EPR). The antioxidant effects of lyophilised CA measured in beef patties containing 0.1% and 0.3% (w/w) CA stored in modified atmosphere packaging (MAP) (80% O2 and 20% CO2) was determined. A preliminary study of gelatine based film containing CA showed a strong antioxidant effect in preventing the degradation of lipid in muscle food. Thus, the present results indicate that CA extract can be used as a natural food antioxidant. PMID:26785344

  2. The greater effectiveness of Glomus mosseae and Glomus intraradices in improving productivity, oil content and tolerance of salt-stressed menthol mint (Mentha arvensis).

    PubMed

    Bharti, Nidhi; Baghel, Savita; Barnawal, Deepti; Yadav, Anju; Kalra, Alok

    2013-07-01

    Mentha arvensis is cultivated in large parts of the world for its menthol-rich essential oil. The study investigates the potential of four mycorrhizal fungi, viz. Glomus mosseae (Gm), Glomus aggregatum (Ga), Glomus fasciculatum (Gf) and Glomus intraradices (Gi) in alleviating NaCl-induced salt stress in Mentha arvensis cv. Kosi and establishes the specificity of interaction between different mycorrhizal species and their effectiveness in mitigating salt stress in Mentha arvensis. Mycorrhizal and non-mycorrhizal Mentha plants were subjected to NaCl-induced salinity. Among the four Glomus species, Gm and Gi reduced salt-induced herb yield losses: a loss of 27.53% and 25.58% respectively under salt stress in comparison to 51.00% in non-mycorrhizal M. arvensis salt-stressed plants. Gm- and Gi-inoculated plants also recorded higher leaf:stem ratio, oil content, and oil yield and menthol concentration in essential oil under both saline and non-saline conditions. Better performance in terms of herb yield, and oil content and yield was observed in Gi- and Gm-inoculated M. arvensis plants, suggesting the capability of Gi and Gm in protecting plants from the detrimental effects of salt stress; beneficial effects of arbuscular mycorrhizal fungi, however, may vary with host and environment. © 2012 Society of Chemical Industry.

  3. Development of a novel Sinapis arvensis disomic addition line in Brassica napus containing the restorer gene for Nsa CMS and improved resistance to Sclerotinia sclerotiorum and pod shattering.

    PubMed

    Wei, Wenhui; Li, Yunchang; Wang, Lijun; Liu, Shengyi; Yan, Xiaohong; Mei, Desheng; Li, Yinde; Xu, Yusong; Peng, Pengfei; Hu, Qiong

    2010-04-01

    An allo-cytoplasmic male sterile line, which was developed through somatic hybridization between Brassica napus and Sinapis arvensis (thus designated as Nsa CMS line), possesses high potential for hybrid production of rapeseed. In order to select for restorer lines, fertile plants derived from the same somatic hybridization combination were self-pollinated and testcrossed with the parental Nsa CMS line for six generations. A novel disomic alien addition line, B. napus-S. arvensis, has been successfully developed. GISH analysis showed that it contains one pair of chromosomes from S. arvensis and 19 pairs from B. napus, and retains stable and regular mitotic and meiotic processes. The addition line displays very strong restoration ability to Nsa CMS line, high resistance to Sclerotinia sclerotiorum and a low incidence of pod shattering. Because the addition line shares these very important agricultural characters, it is a valuable restorer to Nsa CMS line, and is named NR1 here (Nsa restorer no. 1).

  4. Bringing Together Evolution on Serpentine and Polyploidy: Spatiotemporal History of the Diploid-Tetraploid Complex of Knautia arvensis (Dipsacaceae)

    PubMed Central

    Kolář, Filip; Fér, Tomáš; Štech, Milan; Trávníček, Pavel; Dušková, Eva; Schönswetter, Peter; Suda, Jan

    2012-01-01

    Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb Knautia arvensis (Dipsacaceae), a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of K. arvensis allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary ‘dead-ends’ but rather dynamic systems with a potential to further influence the surrounding populations, e

  5. Bringing together evolution on serpentine and polyploidy: spatiotemporal history of the diploid-tetraploid complex of Knautia arvensis (Dipsacaceae).

    PubMed

    Kolář, Filip; Fér, Tomáš; Štech, Milan; Trávníček, Pavel; Dušková, Eva; Schönswetter, Peter; Suda, Jan

    2012-01-01

    Polyploidization is one of the leading forces in the evolution of land plants, providing opportunities for instant speciation and rapid gain of evolutionary novelties. Highly selective conditions of serpentine environments act as an important evolutionary trigger that can be involved in various speciation processes. Whereas the significance of both edaphic speciation on serpentine and polyploidy is widely acknowledged in plant evolution, the links between polyploid evolution and serpentine differentiation have not yet been examined. To fill this gap, we investigated the evolutionary history of the perennial herb Knautia arvensis (Dipsacaceae), a diploid-tetraploid complex that exhibits an intriguing pattern of eco-geographic differentiation. Using plastid DNA sequencing and AFLP genotyping of 336 previously cytotyped individuals from 40 populations from central Europe, we unravelled the patterns of genetic variation among the cytotypes and the edaphic types. Diploids showed the highest levels of genetic differentiation, likely as a result of long term persistence of several lineages in ecologically distinct refugia and/or independent immigration. Recurrent polyploidization, recorded in one serpentine island, seems to have opened new possibilities for the local serpentine genotype. Unlike diploids, the serpentine tetraploids were able to escape from the serpentine refugium and spread further; this was also attributable to hybridization with the neighbouring non-serpentine tetraploid lineages. The spatiotemporal history of K. arvensis allows tracing the interplay of polyploid evolution and ecological divergence on serpentine, resulting in a complex evolutionary pattern. Isolated serpentine outcrops can act as evolutionary capacitors, preserving distinct karyological and genetic diversity. The serpentine lineages, however, may not represent evolutionary 'dead-ends' but rather dynamic systems with a potential to further influence the surrounding populations, e.g., via

  6. Seed dormancy is modulated in recently evolved chlorsulfuron-resistant Turkish biotypes of wild mustard (Sinapis arvensis)

    NASA Astrophysics Data System (ADS)

    Topuz, Muhamet; Nemli, Yildiz; Fatima, Tahira; Mattoo, Autar

    2015-07-01

    Biotypes of the broad-leaved wild mustard (Sinapis arvensis L.) found in wheat fields of Aegean and Marmara region of Turkey were characterized and shown to have developed resistance to sulfonylurea (chlorsulfuron), an inhibitor of acetolactate synthase (ALS). DNA sequence analysis of the ALS genes from two such resistant (‘R’) biotypes, KNF-R1 and KNF-R2, revealed point mutations, CCT (Pro 197) to TCT (Ser 197) in KNF-R1 and CCT (Pro 197) to ACT (Thr 197) in KNF-R2; these substitutions are consistent with the presence of chlorsulfuron-insensitive ALS enzyme activity in the ‘R’ S. arvensis biotypes. An additional phenotype of chlorsulfuron resistance in the Turkish S. arvensis ‘R’ biotypes was revealed in the form of an altered seed dormancy behavior over 4 to 48 months of dry storage (after-ripening) compared to the susceptible (‘S’) biotypes. Seeds of the ‘S’ biotypes dry stored for 4 months had a higher initial germination, which sharply decreased with storage time, while the seeds of the ‘R’ biotypes had lower germination after 4-months storage, rising sharply and peaking thereafter by 24 months’ of dry storage. The ‘R’ biotype seeds continued to maintain a higher germination percentage even after 48 months of after-ripening. The seed weight of ‘R’ and ‘S’ biotypes after-ripened for 4 months was similar but those after-ripened for 48 months differed, ‘R’ seeds were significantly heavier than those of the ‘S’ seeds. Differential seed germinability between ‘S’ and ‘R’ biotypes was found not a case of differential viability, temperature regimen or non-response to pro-germination hormone GA3. These studies are of relevance to ecological fitness of herbicide-resistant biotypes in terms of seed viability and germination.

  7. Studies on activity of various extracts of Mentha arvensis Linn against drug induced gastric ulcer in mammals

    PubMed Central

    Londonkar, Ramesh L; Poddar, Pramod V

    2009-01-01

    AIM: To examine the antiulcerogenic effects of various extracts of Mentha arvensis Linn on acid, ethanol and pylorus ligated ulcer models in rats and mice. METHODS: Various crude extracts of petroleum ether, chloroform, or aqueous at a dose of 2 g/kg po did not produce any signs or symptoms of toxicity in treated animals. In the pyloric ligation model oral administration of different extracts such as petroleum ether, chloroform and aqueous at 375 mg/kg po, standard drug ranitidine 60 mg/kg po and control group 1% Tween 80, 5 mL/kg po to separate groups of Wister rats of either sex (n = 6) was performed. Total acidity, ulcer number, scoring, incidence, area, and ulcer index were assessed. RESULTS: There was a decrease in gastric secretion and ulcer index among the treated groups i.e. petroleum ether (53.4%), chloroform (59.2%), aqueous (67.0%) and in standard drug (68.7%) when compared to the negative control. In the 0.6 mol/L HCl induced ulcer model in rats (n = 6) there was a reduction in ulcerative score in animals receiving petroleum ether (50.5%), chloroform (57.4%), aqueous (67.5%) and standard. drug (71.2%) when compared to the negative control. In the case of the 90% ethanol-induced ulceration model (n = 6) in mice, there was a decrease in ulcer score in test groups of petroleum ether (53.11%), chloroform (62.9%), aqueous (65.4%) and standard drug ranitidine (69.7%) when compared to the negative control. It was found that pre-treatment with various extracts of Mentha arvensis Linn in three rat/mice ulcer models ie ibuprofen plus pyloric ligation, 0.6 mol/L HCl and 90% ethanol produced significant action against acid secretion (49.3 ± 0.49 vs 12.0 ± 0.57, P < 0.001). Pre-treatment with various extracts of Mentha arvensis Linn showed highly -significant activity against gastric ulcers (37.1 ± 0.87 vs 12.0 ± 0.57, P < 0.001). CONCLUSION: Various extracts of Mentha arvensis Linn. 375 mg/kg body weight clearly shows a protective effect against acid secretion

  8. Do the effects of crops on skylark (Alauda arvensis) differ between the field and landscape scales?

    PubMed Central

    Barbottin, Aude; Jiguet, Frédéric; Martin, Philippe

    2015-01-01

    The promotion of biodiversity in agricultural areas involves actions at the landscape scale, and the management of cropping patterns is considered an important means of achieving this goal. However, most of the available knowledge about the impact of crops on biodiversity has been obtained at the field scale, and is generally grouped together under the umbrella term “crop suitability.” Can field-scale knowledge be used to predict the impact on populations across landscapes? We studied the impact of maize and rapeseed on the abundance of skylark (Alauda arvensis). Field-scale studies in Western Europe have reported diverse impacts on habitat selection and demography. We assessed the consistency between field-scale knowledge and landscape-scale observations, using high-resolution databases describing crops and other habitats for the 4 km2 grid scales analyzed in the French Breeding Bird Survey. We used generalized linear models to estimate the impact of each studied crop at the landscape scale. We stratified the squares according to the local and geographical contexts, to ensure that the conclusions drawn were valid in a wide range of contexts. Our results were not consistent with field knowledge for rapeseed, and were consistent for maize only in grassland contexts. However, the effect sizes were much smaller than those of structural landscape features. These results suggest that upscaling from the field scale to the landscape scale leads to an integration of new agronomic and ecological processes, making the objects studied more complex than simple “crop ∗ species” pairs. We conclude that the carrying capacity of agricultural landscapes cannot be deduced from the suitability of their components. PMID:26213656

  9. Bidirectional but asymmetrical sexual hybridization between Brassica carinata and Sinapis arvensis (Brassicaceae).

    PubMed

    Cheung, Kyle W; Razeq, Fakhria M; Sauder, Connie A; James, Tracey; Martin, Sara L

    2015-05-01

    With transgenic crop development it is important to evaluate the potential for transgenes to escape into populations of wild, weedy relatives. Ethiopian mustard (Brassica carinata, BBCC) is easily transformed and is being investigated for uses from biodiesel fuels to biopharmaceuticals. However, little work has been done evaluating its ability to cross with relatives such as wild mustard (Sinapsis arvensis, SrSr), an abundant, cosmopolitan weedy relative. Here we conducted bidirectional crosses with Ethiopian mustard as a maternal parent in 997 crosses and paternal parent in 1,109 crosses. Hybrids were confirmed using flow cytometry and species-specific ITS molecular markers and indicate a high hybridization rate of 6.43 % between Ethiopian mustard (♀) and wild mustard (♂) and a lower, but not insignificant, hybridization rate of 0.01 % in the reverse direction. The majority of the hybrids were homoploid (BCSr) with less than 1 % of pollen production of their parents and low seed production (0.26 seeds/pollination) in crosses and backcrosses indicating a potential for advanced generation hybrids. The accession used had a significant effect on hybrid seed production with different accessions of Ethopian mustard varying in their production of hybrid offspring from 2.69 to 16.34 % and one accession of wild mustard siring almost twice as many hybrid offspring per flower as the other. One pentaploid (BBCCSr) and one hexaploid (BBCCSrSr) hybrid were produced and had higher pollen viability, though no and low seed production, respectively. As wild mustard is self-incompatible and the outcrossing rate of Ethiopian mustard has been estimated as 30 % potential for hybrid production in the wild appears to be high, though the hybridization rate found here represents a worst case scenario as it does not incorporate pre-pollination barriers. Hybridization in the wild needs to be directly evaluated as does the propensity of Ethiopian mustard to volunteer.

  10. [Chemical composition and microstructural peculiarities of overground and underground vegetative organs of field restharrow (Ononis arvensis L.)].

    PubMed

    Sichinava, M B; Mchelidze, K Z; Churadze, M V; Alaniia, M D; Aneli, Dzh N

    2014-06-01

    The paper presents the results of the study of anatomy and chemical composition of Field Restharrow (Ononis arvensis L.). The existence of triterpene alcohol α-onocerin and isoflavons in the overground organs of the plant is established by chemical analysis. Oxycumarines - scopoletin and scopolin are isolated and identified. Morphological characterization of the whole plant is given. Anatomy of the vegetative organs of the species is examined. Among the main microstructural characteristics multilayer integumentary tissues, active periderm and sclerenchyma cells were specified in roots; and complex radial rays and structural units of wood, located radially, were observed in the central cylinder. Shoots are characterized with intensive pubescence. Mechanical tissues of different structures exist in the parenchime of crust and central cylinder of shoots. Vessels with spiral and spiro-annular thickened walls are located in the libriforms of wood. Leaves of Ononis arvensis are bifacial, mesophile is of dorsiventral structure; central conductive bunch is complex-collateral. Basal cells of upper and lower epidermis belong to of bent-walled type, where paracytal and anisocytal cells of stomatal apparatus are scattered chaotically.

  11. Impact assessment of mercury accumulation and biochemical and molecular response of Mentha arvensis: a potential hyperaccumulator plant.

    PubMed

    Manikandan, R; Sahi, S V; Venkatachalam, P

    2015-01-01

    The present study was focused on examining the effect of Hg oxidative stress induced physiochemical and genetic changes in M. arvensis seedlings. The growth rate of Hg treated seedlings was decreased to 56.1% and 41.5% in roots and shoots, respectively, compared to the control. Accumulation of Hg level in both roots and shoots was increased with increasing the concentration of Hg. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were found to be increased with increasing the Hg concentration up to 20 mg/L; however, it was decreased at 25 mg/L Hg concentration. The POX enzyme activity was positively correlated with Hg dose. The changes occurring in the random amplification of ploymorphic DNA (RAPD) profiles generated from Hg treated seedlings included variations in band intensity, disappearance of bands, and appearance of new bands compared with the control seedlings. It was concluded that DNA polymorphisms observed with RAPD profile could be used as molecular marker for the evaluation of heavy metal induced genotoxic effects in plant species. The present results strongly suggested that Mentha arvensis could be used as a potential phytoremediator plant in mercury polluted environment.

  12. Diverse and recombinant DNA betasatellites are associated with a begomovirus disease complex of Digera arvensis, a weed host.

    PubMed

    Mubin, M; Briddon, R W; Mansoor, S

    2009-06-01

    Weeds are considered as a source of new viruses and reservoirs of economically important viruses but are often neglected during diversity studies. Here, we report the complete nucleotide sequences and phylogenetic analyses of the components of a begomovirus disease complex associated with yellow vein disease of Digera arvensis, a common weed. The begomovirus associated with the disease showed 98% nucleotide sequence identity with Cotton leaf curl Rajasthan virus. Two species of betasatellite were identified. The first betasatellite species was an isolate of Ageratum yellow leaf curl betasatellite. The second was a recombinant consisting for the most part of sequence derived from a Tobacco leaf curl betasatellite but with the satellite conserved region (SCR) and some sequence between the SCR and adenine-rich (A-rich) region derived from a Cotton leaf curl Multan betasatellite. The alphasatellite isolated from this weed was near identical to an isolate recently characterized from potato. The presence of multiple and recombinant betasatellites in D. arvensis indicates that weeds can be important sources of multiple begomovirus components that affect crop plants. Furthermore, the presence of a recombinant betasatellite suggested that weeds are likely vessels for recombination and evolution of components of begomovirus complexes.

  13. Impact Assessment of Mercury Accumulation and Biochemical and Molecular Response of Mentha arvensis: A Potential Hyperaccumulator Plant

    PubMed Central

    Manikandan, R.; Sahi, S. V.; Venkatachalam, P.

    2015-01-01

    The present study was focused on examining the effect of Hg oxidative stress induced physiochemical and genetic changes in M. arvensis seedlings. The growth rate of Hg treated seedlings was decreased to 56.1% and 41.5% in roots and shoots, respectively, compared to the control. Accumulation of Hg level in both roots and shoots was increased with increasing the concentration of Hg. Superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were found to be increased with increasing the Hg concentration up to 20 mg/L; however, it was decreased at 25 mg/L Hg concentration. The POX enzyme activity was positively correlated with Hg dose. The changes occurring in the random amplification of ploymorphic DNA (RAPD) profiles generated from Hg treated seedlings included variations in band intensity, disappearance of bands, and appearance of new bands compared with the control seedlings. It was concluded that DNA polymorphisms observed with RAPD profile could be used as molecular marker for the evaluation of heavy metal induced genotoxic effects in plant species. The present results strongly suggested that Mentha arvensis could be used as a potential phytoremediator plant in mercury polluted environment. PMID:25654134

  14. Effect of Sclerotinia sclerotiorum on the disease development, growth, oil yield and biochemical changes in plants of Mentha arvensis

    PubMed Central

    Perveen, K.; Haseeb, A.; Shukla, P.K.

    2010-01-01

    Experiment was carried out to determine the effect of Sclerotinia sclerotiorum on the disease development, growth, oil yield and biochemical changes in the plants of Mentha arvensis. With the increase in initial inoculum levels of S. sclerotiorum a corresponding decrease in plant fresh and dry weights were recorded. The maximum reduction in the shoot-roots/suckers fresh weight and shoot-roots/suckers dry weights (39.8%, 43.6%, 40.3% and 42.9%), respectively, was observed at the highest initial inoculum level of 12 g fungal mycelium/5 kg soil as compared to uninoculated control. The infection of roots and suckers due to S. sclerotiorum increased with increasing initial inoculum levels. At the lowest initial inoculum (1.0 g mycelium/5 kg soil), infection was observed 18.0% and at the highest (12 g mycelium/5 kg soil), it was 80.2%. Significant (P ⩽ 0.01) reduction in oil yield, total chlorophyll, total phenol and total sugar content of M. arvensis plants was observed at the lowest inoculum level as compared to uninoculated control. PMID:23961091

  15. Nickel tolerance of serpentine and non-serpentine Knautia arvensis plants as affected by arbuscular mycorrhizal symbiosis.

    PubMed

    Doubková, Pavla; Sudová, Radka

    2014-04-01

    Serpentine soils have naturally elevated concentrations of certain heavy metals, including nickel. This study addressed the role of plant origin (serpentine vs. non-serpentine) and symbiosis with arbuscular mycorrhizal fungi (AMF) in plant Ni tolerance. A semi-hydroponic experiment involving three levels of Ni and serpentine and non-serpentine AMF isolates and populations of a model plant species (Knautia arvensis) revealed considerable negative effects of elevated Ni availability on both plant and fungal performance. Plant growth response to Ni was independent of edaphic origin; however, higher Ni tolerance of serpentine plants was indicated by a smaller decline in the concentrations of photosynthetic pigments and restricted root-to-shoot Ni translocation. Serpentine plants also retained relatively more Mg in their roots, resulting in a higher shoot Ca/Mg ratio. AMF inoculation, especially with the non-serpentine isolate, further aggravated Ni toxicity to host plants. Therefore, AMF do not appear to be involved in Ni tolerance of serpentine K. arvensis plants.

  16. Effect of water stress on the agressiveness of oilsseed rape (Brassica napus L.) and two mustards (Sinapis alba L. and S. arvensis L.).

    PubMed

    Maataoui, A; Talouizte, A; Benbella, M; Bouhache, M

    2003-01-01

    Oilseed rape (Brassica napus L.), a winter sown crop, may compete for water especially with Brassicaceae weeds. Investigating plant competition under water stress conditions is necessary for achieving a good yield in a Mediterranean climate characterized by a scarse water availability. This experiment was carried out to study the competiveness of oilseed rape (Brassica napus L.) with two brassicaceae weeds (Sinapis alba L. and S. arvensis L.). Species were grown at a density of two plants per bucket either in monoculture or as a binary mixture under water stress conditions in a greenhouse. Results of monoculture showed that B. napus had the highest shoot dry matter. Shoot dry matter of B. napus was more reduced by intraspecific competition than by interspecific competition due to S. arvensis. Shoot dry matter of S. alba in monoculture was higher than in mixture with S. arvensis, but more reduced in mixture with B. napus. In case of S. arvensis, shoot dry matter was more reduced by interspecific competition than by intraspecific competition. Agressivity based on grain yield showed, that B. napus was the most agressive species followed by S. alba. This agressivity did not change by the imposed water stress.

  17. Eriophyoid mites (Acari: Prostigmata: Eriophyoidea) from Hungary: a new species on Agrimonia eupatoria (Rosaceae) and new record on Convolvulus arvensis (Convolvulaceae).

    PubMed

    Ripka, Géza

    2014-12-22

    A new species of eriophyoid mite, Aculus castriferrei n. sp., associated with Agrimonia eupatoria (Rosaceae) is described and illustrated from Hungary. Morphological differences distinguishing this vagrant species from other rosaceous inhabiting congeners are discussed. Aceria malherbae Nuzzaci is a new record for the eriophyoid fauna of Hungary after it was found causing severe damage symptoms to Convolvulus arvensis L. (Convolvulaceae).

  18. CCl4 induced genotoxicity and DNA oxidative damages in rats: hepatoprotective effect of Sonchus arvensis.

    PubMed

    Alkreathy, Huda Mohammad; Khan, Rahmat Ali; Khan, Muhammad Rashid; Sahreen, Sumaira

    2014-11-21

    Sonchus arvesis is traditionally reported in various human ailments including hepatotoxicity in Pakistan. Presently we designed to assess the protective effects of methanolic extract of Sonchus arvesis against carbon tetrachloride induced genotoxicity and DNA oxidative damages in hepatic tissues of experimental rats. 36 male Sprague-Dawley rats were randomly divided into 6 groups to evaluate the hepatoprotective effects of Sonchus arvensis against CCl4 induced genotoxicity, DNA damages and antioxidant depletion. Rats of normal control group were given free access of food and water add labitum. Group II rats received 3 ml/kg of CCl4 (30% in olive oil v/v) via the intraperitoneal route twice a week for four weeks. Group III and IV received 1 ml of 100 mg/kg b.w. and 200 mg/kg b.w. SME via gavage after 48 h of CCl4 treatment whereas group V was given 1 ml of silymarin (100 mg/kg b.w.) after 48 h of CCl4 treatment. Group VI only received 200 mg/kg b.w. SME. Protective effects of SME were checked by measuring serum markers, activities of antioxidant enzymes, genotoxicity and DNA dmages. Results of the present study showed that treatment of SME reversed the activities of serum marker enzymes and cholesterol profile as depleted with CCl4 treatment. Activities of endogenous antioxidant enzymes of liver tissue homogenate; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSHpx), glutathione-S-transferase (GST) and glutathione reductase (GSR) were reduced with administration of CCl4, which were returned to the control level with SME treatment. CCl4-induced hepatic cirrhosis decreased hepatic glutathione (GSH) and increased lipid peroxidative products (TBARS), were normalized by treatment with SME. Moreover, administration of CCl4 caused genotoxicity and DNA fragmentation which were significantly restored towards the normal level with SME. These results reveal that treatment of SME may be useful in the prevention of hepatic stress.

  19. Evolutionary processes in a continental island system: molecular phylogeography of the Aegean Nigella arvensis alliance (Ranunculaceae) inferred from chloroplast DNA.

    PubMed

    Bittkau, C; Comes, H P

    2005-11-01

    Continental shelf island systems, created by rising sea levels, provide a premier setting for studying the effects of past fragmentation, dispersal, and genetic drift on taxon diversification. We used phylogeographical (nested clade) and population genetic analyses to elucidate the relative roles of these processes in the evolutionary history of the Aegean Nigella arvensis alliance (= 'coenospecies'). We surveyed chloroplast DNA (cpDNA) variation in 455 individuals from 47 populations (nine taxa) of the alliance throughout its core range in the Aegean Archipelago and surrounding mainland areas of Greece and Turkey. The study revealed the presence of three major lineages, with largely nonoverlapping distributions in the Western, Central, and Eastern Aegean. There is evidence supporting the idea that these major lineages evolved in situ from a widespread (pan-Aegean) ancestral stock as a result of multiple fragmentation events, possibly due to the influence of post-Messinian sea flooding, Pleistocene eustatic changes and corresponding climate fluctuations. Over-sea dispersal and founder events appear to have played a rather insignificant role in the group's history. Rather, all analytical approaches identified the alliance as an organism group with poor seed dispersal capabilities and a susceptibility to genetic drift. In particular, we inferred that the observed level of cpDNA differentiation between Kikladian island populations of Nigella degenii largely reflects population history, (viz. Holocene island fragmentation) and genetic drift in the near absence of seed flow since their time of common ancestry. Overall, our cpDNA data for the N. arvensis alliance in general, and N. degenii in particular, indicate that historical events were important in determining the phylogeographical patterns seen, and that genetic drift has historically been relatively more influential on population structure than has cytoplasmic gene flow.

  20. Do seed mass and family affect germination and juvenile performance in Knautia arvensis? A study using failure-time methods

    NASA Astrophysics Data System (ADS)

    Vange, Vibekke; Heuch, Ivar; Vandvik, Vigdis

    2004-05-01

    Germination and seedling establishment are vulnerable stages in the plant life cycle. We investigated how seed mass and family (progeny origin) affect germination and juvenile performance in the grassland herb Knautia arvensis. Seeds were produced by cross-pollination by hand. The fate of 15 individually weighed seeds from each of 15 plants was followed during a 3-month growth chamber experiment. Progeny origin affected germination, both through seed mass and as an independent factor. Two groups of progenies could be distinguished by having rapid or delayed germination. The two groups had similar mean seed masses, but a positive relationship between seed mass and germination rate could be established only among the rapidly germinating progenies. These biologically relevant patterns were revealed because timing of germination was taken into account in the analyses, not only frequencies. Time-to-event data were analysed with failure-time methods, which gave more stable estimates for the relation between germination and seed mass than the commonly applied logistic regression. Progeny origin and seed mass exerted less impact on later characters like juvenile survival, juvenile biomass, and rosette number. These characters were not affected by the timing of germination under the competition-free study conditions. The decrease in the effect of progeny origin from the seed and germination to the juvenile stages suggests that parental effects other than those contributing to the offspring genotype strongly influenced the offspring phenotype at the earliest life stages. Further, the division of progeny germination patterns into two fairly distinct groups indicates that there was a genetic basis for the variation in stratification requirements among parental plants. Field studies are needed to elucidate effects of different timing of germination in the seasonal grasslands that K. arvensis inhabits.

  1. Comparative genomic in situ hybridization (cGISH) analysis of the genomic relationships among Sinapis arvensis, Brassica rapa and Brassica nigra.

    PubMed

    Mao, Shufang; Han, Yonghua; Wu, Xiaoming; An, Tingting; Tang, Jiali; Shen, Junjun; Li, Zongyun

    2012-06-01

    To further understand the relationships between the SS genome of Sinapis arvensis and the AA, BB genomes in Brassica, genomic DNA of Sinapis arvensis was hybridized to the metaphase chromosomes of Brassica nigra (BB genome), and the metaphase chromosomes and interphase nucleus of Brassica rapa (AA genome) by comparative genomic in situ hybridization (cGISH). As a result, every chromosome of B. nigra had signals along the whole chromosomal length. However, only half of the condensed heterochromatic areas in the interphase nucleus and the chromosomes showed rich signals in Brassica rapa. Interphase nucleus and the metaphase chromosomes of S. arvensis were simultaneously hybridized with digoxigenin-labeled genomic DNA of B. nigra and biotin-labeled genomic DNA of B. rapa. Signals of genomic DNA of B. nigra hybridized throughout the length of all chromosomes and all the condensed heterochromatic areas in the interphase nucleus, except chromosome 4, of which signals were weak in centromeric regions. Signals of the genomic DNA of B. rapa patterned the most areas of ten chromosomes and ten condensed heterochromatic areas, others had less signals. The results showed that the SS genome had homology with AA and BB genomes, but the homology between SS genome and AA genome was clearly lower than that between the SS genome and BB genome.

  2. Soil nutritional status, not inoculum identity, primarily determines the effect of arbuscular mycorrhizal fungi on the growth of Knautia arvensis plants.

    PubMed

    Doubková, Pavla; Kohout, Petr; Sudová, Radka

    2013-10-01

    Arbuscular mycorrhizal (AM) symbiosis is among the factors contributing to plant survival in serpentine soils characterised by unfavourable physicochemical properties. However, AM fungi show a considerable functional diversity, which is further modified by host plant identity and edaphic conditions. To determine the variability among serpentine AM fungal isolates in their effects on plant growth and nutrition, a greenhouse experiment was conducted involving two serpentine and two non-serpentine populations of Knautia arvensis plants grown in their native substrates. The plants were inoculated with one of the four serpentine AM fungal isolates or with a complex AM fungal community native to the respective plant population. At harvest after 6-month cultivation, intraradical fungal development was assessed, AM fungal taxa established from native fungal communities were determined and plant growth and element uptake evaluated. AM symbiosis significantly improved the performance of all the K. arvensis populations. The extent of mycorrhizal growth promotion was mainly governed by nutritional status of the substrate, while the effect of AM fungal identity was negligible. Inoculation with the native AM fungal communities was not more efficient than inoculation with single AM fungal isolates in any plant population. Contrary to the growth effects, a certain variation among AM fungal isolates was revealed in terms of their effects on plant nutrient uptake, especially P, Mg and Ca, with none of the AM fungi being generally superior in this respect. Regardless of AM symbiosis, K. arvensis populations significantly differed in their relative nutrient accumulation ratios, clearly showing the plant's ability to adapt to nutrient deficiency/excess.

  3. Chemical Variability, Antioxidant and Antifungal Activities of Essential Oils and Hydrosol Extract of Calendula arvensis L. from Western Algeria.

    PubMed

    Belabbes, Rania; Dib, Mohammed El Amine; Djabou, Nassim; Ilias, Faiza; Tabti, Boufeldja; Costa, Jean; Muselli, Alain

    2017-05-01

    The chemical composition of the essential oils and hydrosol extract from aerial parts of Calendula arvensis L. was investigated using GC-FID and GC/MS. Intra-species variations of the chemical compositions of essential oils from 18 Algerian sample locations were investigated using statistical analysis. Chemical analysis allowed the identification of 53 compounds amounting to 92.3 - 98.5% with yields varied of 0.09 - 0.36% and the main compounds were zingiberenol 1 (8.7 - 29.8%), eremoligenol (4.2 - 12.5%), β-curcumene (2.1 - 12.5%), zingiberenol 2 (4.6 - 19.8%) and (E,Z)-farnesol (3.5 - 23.4%). The study of the chemical variability of essential oils allowed the discrimination of two main clusters confirming that there is a relation between the essential oil compositions and the harvest locations. Different concentrations of essential oil and hydrosol extract were prepared and their antioxidant activity were assessed using three methods (2,2-diphenyl-1-picrylhydrazyl, Ferric-Reducing Antioxidant Power Assay and β-carotene). The results showed that hydrosol extract presented an interesting antioxidant activity. The in vitro antifungal activity of hydrosol extract produced the best antifungal inhibition against Penicillium expansum and Aspergillus niger, while, essential oil was inhibitory at relatively higher concentrations. Results showed that the treatments of pear fruits with essential oil and hydrosol extract presented a very interesting protective activity on disease severity of pears caused by P. expansum. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  4. Distribution of hydrogen-metabolizing bacteria in alfalfa field soil. [Medicago sativa L. ; Convolvulus arvensis L. ; Rhizobium meliloti

    SciTech Connect

    Cunningham, S.D.; Kapulnik, Y.; Phillips, D.A.

    1986-11-01

    H/sub 2/ evolved by alfalfa root nodules during the process of N/sub 2/ fixation may be an important factor influencing the distribution of soil bacteria. To test this hypothesis under field conditions, over 700 bacterial isolates were obtained from fallow soil or from the 3-mm layer of soil surrounding alfalfa (Medicago sativa L.) root nodules, alfalfa roots, or bindweed (Convolvulus arvensis L.) roots. Bacteria were isolated under either aerobic or microaerophilic conditions and were tested for their capacity to metabolize H/sub 2/. Isolates showing net H/sub 2/ uptake and /sup 3/H/sub 2/ incorporation activity under laboratory conditions were assigned a Hup/sup +/ phenotype, whereas organisms with significant H/sub 2/ output capacity were designated as a Hout/sup +/ phenotype. Under aerobic isolation conditions two Hup/sup +/ isolates were obtained, whereas under microaerophilic conditions five Hup/sup +/ and two Hout/sup +/ isolates were found. The nine isolates differed on the basis of 24 standard bacteriological characteristics or fatty acid composition. Five of the nine organisms were isolated from soil around root nodules, whereas the other four were found distributed among the other three soil environments. On the basis of the microaerophilic isolations, 4.8% of the total procaryotic isolates from soil around root nodules were capable of oxidizing H/sub 2/, and 1.2% could produce H/sub 2/. Two of the Hup/sup +/ isolates were identified as Rhizobium meliloti by root nodulation tests, but the fact that none of the isolates reduced C/sub 2/H/sub 2/ under the assay conditions suggested that the H/sub 2/ metabolism traits were associated with various hydrogenase systems rather than with nitrogenase activity.

  5. How to identify dear enemies: the group signature in the complex song of the skylark Alauda arvensis.

    PubMed

    Briefer, Elodie; Aubin, Thierry; Lehongre, Katia; Rybak, Fanny

    2008-02-01

    Song geographic variation and Neighbour-Stranger (N-S) discrimination have been intensively but separately studied in bird species, especially in those with small- to medium-sized repertoires. Here, we establish a link between the two phenomena by showing that dialect features are used for N-S recognition in a territorial species with a large repertoire, the skylark Alauda arvensis. In this species, during the breeding season, many pairs settle in stable and adjoining territories gathered in locations spaced by a few kilometres. In a first step, songs produced by males established in different locations were recorded, analyzed and compared to identify possible microgeographic variation at the syntax level. Particular common sequences of syllables (phrases) were found in the songs of all males established in the same location (neighbours), whereas males of different locations (strangers) shared only few syllables and no sequences. In a second step, playback experiments were conducted and provided evidence for N-S discrimination consistent with the dear-enemy effect, i.e. reduced aggression from territorial birds towards neighbours than towards strangers. In addition, a similar response was observed when a ;chimeric' signal (shared phrases of the location artificially inserted in the song of a stranger) and a neighbour song were broadcast, indicating that shared sequences were recognized and identified as markers of the group identity. We thus show experimentally that the shared phrases found in the songs of neighbouring birds constitute a group signature used by birds for N-S discrimination, and serve as a basis for the dear-enemy effect.

  6. Comparative study of biological activities and phytochemical composition of two rose hips and their preserves: Rosa canina L. and Rosa arvensis Huds.

    PubMed

    Nađpal, Jelena D; Lesjak, Marija M; Šibul, Filip S; Anačkov, Goran T; Četojević-Simin, Dragana D; Mimica-Dukić, Neda M; Beara, Ivana N

    2016-02-01

    The aim of this study was to compare phenolic profile, vitamin C content, antioxidant, anti-inflammatory and cytotoxic activity of rose hips and the preserves (purée and jam) of two Rosa species: renowned Rosa canina L. and unexplored Rosa arvensis Huds. The liquid chromatography-tandem mass spectrometry analysis of 45 phenolics resulted in quantification of 14 compounds, with quercitrin, gallic and protocatechuic acids as the most dominant. High antioxidant potential of R. canina and a moderate activity of R. arvensis extracts were determined through several assays. Purée of both species and methanol extract of air-dried R. canina hips showed some anti-inflammatory (cyclooxygenase-1 and 12-lipooxygense inhibition potency) activity. Purée of R. canina exerted cytotoxic activity only against the HeLa cell line among several others (HeLa, MCF7, HT-29 and MRC-5). The presented results support traditional use of rose hips and their fruit preserves as food with health and nutritional benefits.

  7. Mentha arvensis (Linn.)-mediated green silver nanoparticles trigger caspase 9-dependent cell death in MCF7 and MDA-MB-231 cells

    PubMed Central

    Banerjee, Prajna Paramita; Bandyopadhyay, Arindam; Harsha, Singapura Nagesh; Policegoudra, Rudragoud S; Bhattacharya, Shelley; Karak, Niranjan; Chattopadhyay, Ansuman

    2017-01-01

    Introduction Leaf extract of Mentha arvensis or mint plant was used as reducing agent for the synthesis of green silver nanoparticles (GSNPs) as a cost-effective, eco-friendly process compared to that of chemical synthesis. The existence of nanoparticles was characterized by ultraviolet–visible spectrophotometry, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, atomic-force microscopy and transmission electron microscopy analyses, which ascertained the formation of spherical GSNPs with a size range of 3–9 nm. Anticancer activities against breast cancer cell lines (MCF7 and MDA-MB-231) were studied and compared with those of chemically synthesized (sodium borohydride [NaBH4]-mediated) silver nanoparticles (CSNPs). Materials and methods Cell survival of nanoparticle-treated and untreated cells was studied by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell-cycle analyses were carried out using fluorescence-activated cell sorting. Cell morphology was observed by fluorescence microscopy. Expression patterns of PARP1, P53, P21, Bcl2, Bax and cleaved caspase 9 as well as caspase 3 proteins in treated and untreated MCF7 and MDA-MB-231 cells were studied by Western blot method. Results MTT assay results showed that Mentha arvensis-mediated GSNPs exhibited significant cytotoxicity toward breast cancer cells (MCF7 and MDA-MB-231), which were at par with that of CSNPs. Cell cycle analyses of MCF7 cells revealed a significant increase in sub-G1 cell population, indicating cytotoxicity of GSNPs. On the other hand, human peripheral blood lymphocytes showed significantly less cytotoxicity compared with MCF7 and MDA-MB-231 cells when treated with the same dose. Expression patterns of proteins suggested that GSNPs triggered caspase 9-dependent cell death in both cell lines. The Ames test showed that GSNPs were nonmutagenic in nature. Conclusion GSNPs synthesized using Mentha

  8. Mentha arvensis (Linn.)-mediated green silver nanoparticles trigger caspase 9-dependent cell death in MCF7 and MDA-MB-231 cells.

    PubMed

    Banerjee, Prajna Paramita; Bandyopadhyay, Arindam; Harsha, Singapura Nagesh; Policegoudra, Rudragoud S; Bhattacharya, Shelley; Karak, Niranjan; Chattopadhyay, Ansuman

    2017-01-01

    Leaf extract of Mentha arvensis or mint plant was used as reducing agent for the synthesis of green silver nanoparticles (GSNPs) as a cost-effective, eco-friendly process compared to that of chemical synthesis. The existence of nanoparticles was characterized by ultraviolet-visible spectrophotometry, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, atomic-force microscopy and transmission electron microscopy analyses, which ascertained the formation of spherical GSNPs with a size range of 3-9 nm. Anticancer activities against breast cancer cell lines (MCF7 and MDA-MB-231) were studied and compared with those of chemically synthesized (sodium borohydride [NaBH4]-mediated) silver nanoparticles (CSNPs). Cell survival of nanoparticle-treated and untreated cells was studied by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell-cycle analyses were carried out using fluorescence-activated cell sorting. Cell morphology was observed by fluorescence microscopy. Expression patterns of PARP1, P53, P21, Bcl2, Bax and cleaved caspase 9 as well as caspase 3 proteins in treated and untreated MCF7 and MDA-MB-231 cells were studied by Western blot method. MTT assay results showed that Mentha arvensis-mediated GSNPs exhibited significant cytotoxicity toward breast cancer cells (MCF7 and MDA-MB-231), which were at par with that of CSNPs. Cell cycle analyses of MCF7 cells revealed a significant increase in sub-G1 cell population, indicating cytotoxicity of GSNPs. On the other hand, human peripheral blood lymphocytes showed significantly less cytotoxicity compared with MCF7 and MDA-MB-231 cells when treated with the same dose. Expression patterns of proteins suggested that GSNPs triggered caspase 9-dependent cell death in both cell lines. The Ames test showed that GSNPs were nonmutagenic in nature. GSNPs synthesized using Mentha arvensis may be considered as a promising anticancer agent in

  9. Effect of aqueous extracts of Mentha arvensis (mint) and Piper betle (betel) on growth and citrinin production from toxigenic Penicillium citrinum.

    PubMed

    Panda, Pragyanshree; Aiko, Visenuo; Mehta, Alka

    2015-06-01

    Due to growing concern of consumers about chemical residues in food products, the demand for safe and natural food is increasing greatly. The use of natural additives such as spices and herbal oil as seasoning agents for their antimicrobial activity has been extensively investigated. This paper discusses the efficacy of the aqueous extract of mint (Mentha arvensis) and betel (Piper betle) on the mycelial growth and citrinin production of Penicillium citrinum. The present investigation revealed that mint extract inhibited citrinin production up to 73 % without inhibiting the mycelium growth. The citrinin production decreased with increase in the concentration of mint extract as observed from the data obtained from High pressure liquid chromatography. The samples also showed reduced cytotoxicity on HeLa cells. On the other hand betel extract resulted in stimulatory effect on citrinin production and mycelial growth. The study showed that mint extract has the potential to be used safely for restraining citrinin contamination.

  10. Susceptibility of herpes simplex virus type 1 to monoterpenes thymol, carvacrol, p-cymene and essential oils of Sinapis arvensis L., Lallemantia royleana Benth. and Pulicaria vulgaris Gaertn.

    PubMed

    Sharifi-Rad, J; Salehi, B; Schnitzler, P; Ayatollahi, S A; Kobarfard, F; Fathi, M; Eisazadeh, M; Sharifi-Rad, M

    2017-08-30

    In recent years, with increased the prevalence of viral infections and having no specific for  their treatment  and also the continuous appearance of resistant viral strains, the finding of novel antiviral agents is necessary. In this study, monoterpenes of thymol, carvacrol, p-cymene and essential oils from Sinapis arvensis L., Lallemantia royleana Benth. and Pulicaria vulgaris Gaertn. were screened for their inhibitory effect against herpes simplex virus type 1 (HSV-1) in vitro on Vero cell line CCL-81-ATCC using a plaque reduction assay. The antiviral activity of three monoterpenes (thymol, carvacrol and p-cymene) and three essential oils were evaluated by cytotoxicity assay, direct plaque test. In addition, the modes of antiviral action of these compounds were investigated during the viral infection cycle. Results showed that the inhibitory concentrations (IC50) were determined at 0.002%, 0.037%, >0.1%, 0.035%, 0.018% and 0.001% for thymol, carvacrol, p-cymene, S. arvensis oil, L. royleana oil and P. vulgaris oil, respectively. A manifestly dose-dependent virucidal activity against HSV-1 could be exhibited for compounds tested. In order to determine the mode of the inhibitory effect, compounds were added at different stages during the viral infection cycle. At maximum noncytotoxic concentrations of the compounds, plaque formation was significantly reduced by more than 80% when HSV-1 was preincubated with p-cymene. However, no inhibitory effect could be observed when the compounds were added to the cells prior to infection with HSV-1 or after the adsorption period. These results indicate that compounds affected HSV-1 mostly before adsorption and might interact with the viral envelope. Thymol exhibited a high selectivity index and seems to be a promising candidate for topical therapeutic application as antiviral agent for treatment of herpetic infections.

  11. Towards resolving the Knautia arvensis agg. (Dipsacaceae) puzzle: primary and secondary contact zones and ploidy segregation at landscape and microgeographic scales

    PubMed Central

    Kolář, Filip; Štech, Milan; Trávníček, Pavel; Rauchová, Jana; Urfus, Tomáš; Vít, Petr; Kubešová, Magdalena; Suda, Jan

    2009-01-01

    Background and Aims Detailed knowledge of variations in ploidy levels and their geographic distributions is one of the key tasks faced in polyploid research in natural systems. Flow cytometry has greatly facilitated the field of cytogeography by allowing characterization of ploidy levels at both the regional and population scale, and at multiple stages of the life cycle. In the present study, flow cytometry was employed to investigate the patterns and dynamics of ploidy variation in the taxonomically challenging complex Knautia arvensis (Dipsacaceae) and some of its allies (K. dipsacifolia, K. slovaca) in Central Europe. Methods DNA ploidy levels were estimated by DAPI flow cytometry in 5205 adult plants, 228 seedlings and 400 seeds collected from 292 Knautia populations in seven European countries. The flow cytometric data were supplemented with conventional chromosome counts. A subset of 79 accessions was subjected to estimation of the absolute genome size using propidium iodide flow cytometry. Key Results and Conclusions Five different ploidy levels (from 2x to 6x) were found, with triploids of K. arvensis being recorded for the first time. The species also exhibited variation in the monoploid genome size, corresponding to the types of habitats occupied (grassland diploid populations had larger genome sizes than relict and subalpine diploid populations). Disregarding relict populations, the distribution of 2x and 4x cytotypes was largely parapatric, with a diffuse secondary contact zone running along the north-west margin of the Pannonian basin. Spatial segregation of the cytotypes was also observed on regional and microgeographic scales. The newly detected sympatric growth of diploids and tetraploids in isolated relict habitats most likely represents the primary zone of cytotype contact. Ploidy level was found to be a major determinant of the strength of inter-cytotype reproductive barriers. While mixed 2x + 4x populations virtually lacked the intermediate

  12. Influence of the leaf extract of Mentha arvensis Linn. (mint) on the survival of mice exposed to different doses of gamma radiation.

    PubMed

    Jagetia, Ganesh Chandra; Baliga, Manjeshwar Shrinath

    2002-02-01

    The aim of the present study was to evaluate the radioprotective effect of Mentha arvensis (mint) on the survival of mice exposed to various doses of whole-body gamma radiation. The radioprotective effect of various doses (0, 2.5, 5, 10, 20, 40 and 80 mg/kg body weight) of chloroform extract of mint (Mentha arvensis Linn.) was studied in mice exposed to 10 Gy gamma radiation. The 10 mg/kg of mint extract was found to afford best protection as evidenced by the highest number of survivors in this group at 30 days post-irradiation, and further experiments were carried out using this dose of mint extract. The mice treated with 10 mg/kg body weight mint extract or oil were exposed to 6, 7, 8, 9 and 10 Gy of gamma radiation and observed for the induction of radiation-sickness and mortality up to 30 days post-irradiation. The mint extract pretreatment was found to reduce the severity of symptoms of radiation sickness and mortality at all exposure doses and a significant increase in the animal survival was observed when compared with the oil + irradiation group. All of the animals that were treated with 10 mg/kg mint extract and then exposed to 7 Gy irradiation were protected against the radiation-induced mortality when compared with the concurrent oil + irradiation group, in which 20% animals died by 30 days post-irradiation. The mint extract treatment protected the mice against the gastrointestinal death as well as bone marrow deaths. The DRF was found to be 1.2. The drug was non-toxic up to a dose of 1,000 mg/kg body weight, the highest drug dose that could be tested for acute toxicity. From our study it is clear that mint extract provides protection against the radiation-induced sickness and mortality and the optimum protective dose of 10 mg/kg is safe from the point of drug-induced toxicity.

  13. Medicinal and aromatic plant materials as nitrification inhibitors for augmenting yield and nitrogen uptake of Japanese mint (Mentha arvensis L. Var. Piperascens).

    PubMed

    Kiran, Usha; Patra, D D

    2003-02-01

    Pot experiments were conducted to evaluate the relative performance of medicinal and aromatic plant materials and dicyandiamide (DCD) as nitrification inhibitors to regulate transformation of N from urea. Their effect on the efficiencies of use of N by Japanese mint (Mentha arvensis cv. Hy 77) was tested. Urea was coated with these materials viz., Mentha spicata, Artemisia annua or DCD at the rate of 5% (w/w) of fertilizer urea using an appropriate coating technique. Nimin (tetranortriterpenoids, an ethanol extract of neem (Azadirachta indica Juss) coating was done at the rate of 1% w/w of urea. Fertilizer nitrogen was applied at 100 and 200 mg kg(-1) soil. These natural coating materials significantly increased the herb and essential oil yields of the crop at both rates of fertilizer nitrogen compared to urea alone and were found to be as effective as DCD in retarding NO3- formation in soil. Herb yield increased by 6-81% when compared to uncoated urea. The increase in essential oil yield ranged between 3% and 68% due to coating. The effectiveness of the nitrification-inhibitor--coated urea, however, varied with the soils used and the rate of fertilizer nitrogen applied. The results suggest that the natural products could be potential nitrification inhibitors for increasing fertilizer N use efficiency.

  14. Bioactive Polyphenols from the Methanol Extract of Cnicus arvensis (L.) Roth Demonstrated Antinociceptive and Central Nervous System Depressant Activities in Mice.

    PubMed

    Rahman, Mahmudur; Khatun, Amina; Nesa, Mst Luthfun; Hossain, Hemayet; Jahan, Ismet Ara

    2015-01-01

    Cnicus arvensis is used by many ethnic groups for inflammation, pain, and other ailments. In this study, reducing sugar, carbohydrate, alkaloid, steroid, tannin, flavonoid, and saponin groups were identified using standard chromogenic method. In high-performance liquid chromatography, vanillic acid and epicatechin were identified in the extract. Antinociceptive test by acetic acid induced writhing inhibition resulted 43.17 and 95.08% inhibition for 100 and 200 mg/kg body weight, comparing with standard diclofenac Na with 74.86% inhibition for 25 mg/kg body weight. In formalin induced paw licking test for antinociceptive activity, the extract inhibited 69.87 and 75.55% licking for 150 and 300 mg/kg body weight comparing with the inhibition (68.56%) of diclofenac Na for 10 mg/kg body weight at first phase. At late phase, the extract showed 73.12 and 87.46% licking comparing with licking inhibition (71.69%) by diclofenac Na at the same dose. In open field test for CNS depressant activity, the extract showed depression of locomotor activity for 150 and 300 mg/kg body weight comparing with diazepam for 10 mg/kg body weight. All results were statistically significant (P < 0.01). The identified polyphenols are reputed for antinociceptive and CNS depressant activity. The present findings support the use of this plant in pain.

  15. Bioactive Polyphenols from the Methanol Extract of Cnicus arvensis (L.) Roth Demonstrated Antinociceptive and Central Nervous System Depressant Activities in Mice

    PubMed Central

    Nesa, Mst. Luthfun; Jahan, Ismet Ara

    2015-01-01

    Cnicus arvensis is used by many ethnic groups for inflammation, pain, and other ailments. In this study, reducing sugar, carbohydrate, alkaloid, steroid, tannin, flavonoid, and saponin groups were identified using standard chromogenic method. In high-performance liquid chromatography, vanillic acid and epicatechin were identified in the extract. Antinociceptive test by acetic acid induced writhing inhibition resulted 43.17 and 95.08% inhibition for 100 and 200 mg/kg body weight, comparing with standard diclofenac Na with 74.86% inhibition for 25 mg/kg body weight. In formalin induced paw licking test for antinociceptive activity, the extract inhibited 69.87 and 75.55% licking for 150 and 300 mg/kg body weight comparing with the inhibition (68.56%) of diclofenac Na for 10 mg/kg body weight at first phase. At late phase, the extract showed 73.12 and 87.46% licking comparing with licking inhibition (71.69%) by diclofenac Na at the same dose. In open field test for CNS depressant activity, the extract showed depression of locomotor activity for 150 and 300 mg/kg body weight comparing with diazepam for 10 mg/kg body weight. All results were statistically significant (P < 0.01). The identified polyphenols are reputed for antinociceptive and CNS depressant activity. The present findings support the use of this plant in pain. PMID:25648520

  16. Productivity and quality of volatile oil extracted from Mentha spicata and M. arvensis var. piperascens grown by a hydroponic system using the deep flow technique.

    PubMed

    Vimolmangkang, Sornkanok; Sitthithaworn, Worapan; Vannavanich, Danai; Keattikunpairoj, Sunisa; Chittasupho, Chuda

    2010-01-01

    The purpose of this study was to determine the differences between spearmint (Mentha spicata L.) and Japanese mint (M. arvensis L. var. piperascens Malinv.) cultivated in either soil or nutrient solution using the deep flow technique (DFT). The differences were measured in terms of harvest period (full bloom period) and quantity and chemical components of volatile oils. The spearmint and Japanese mint were cultivated in four different nutrient formulas: plant standard nutrient, plant standard nutrient with an amino acid mixture, plant standard nutrient with a sulphur compound, and a combination of plant standard nutrient with an amino acid mixture and a sulphur compound. We observed that cultivation of spearmint and Japanese mint in nutrient solution using DFT is an effective method to provide high production of volatile oil, since it results in an earlier harvest period and higher quantity of volatile oil. We determined that for spearmint an amino acid mixture is an appropriate nutrient supplement to enhance production of volatile oil with optimum carvone content. Finally, we observed high menthol content in Japanese mint grown in all four nutrient formulas; however, supplementation with a combination of sulphur fertilisation and amino acid mixture yields the highest quantity of volatile oil.

  17. Efficacy of mint (Mentha arvensis) leaf and citrus (Citrus aurantium) peel extracts as natural preservatives for shelf life extension of chill stored Indian mackerel.

    PubMed

    Viji, Pankyamma; Binsi, Puthanpurakkal Kizhakkathil; Visnuvinayagam, Sivam; Bindu, Jaganath; Ravishankar, Chandragiri Nagarajarao; Srinivasa Gopal, Teralandur Krishnaswamy

    2015-10-01

    Efficacy of mint (Mentha arvensis) leaf and citrus (Citrus aurantium) peel extracts in retarding the quality changes in Indian mackerel during chilled storage was investigated. Mint leaf extract showed higher quantity of phenolics and superior in-vitro antioxidant activities than citrus peel extract. Gutted mackerel were given a dip treatment in mint extract (0.5 %, w/v) and citrus extract (1 % w/v), packed in LDPE pouches and stored at 0-2 °C. The biochemical quality indices viz. total volatile base nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), free fattyacids (FFA) were significantly (p < 0.05) lower in mint extract (ME) treated fishes compared to citrus extract (CE) treated and control fishes (C) without any treatment. Plant extract treatment significantly inhibited lipid oxidation in mackerel as indicated by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Aerobic plate count (APC) was markedly higher in C group followed by CE group throughout the storage period. As per sensory evaluation, shelf life of Indian mackerel was determined to be 11-13 days for C group, 13-15 days for CE group and 16-17 days for ME group, during storage at 0-2 °C.

  18. Burial and seed survival in Brassica napus subsp. oleifera and Sinapis arvensis including a comparison of transgenic and non-transgenic lines of the crop.

    PubMed Central

    Hails, R S; Rees, M; Kohn, D D; Crawley, M J

    1997-01-01

    The creation of transgenic plants through genetic engineering has focused interest on how the fitness of a plant species may be altered by small changes in its genome. This study concentrates on a key component of fitness: persistence of seeds overwinter. Seeds of three lines of oilseed rape (Brassica napus subsp. oleifera DC Metzger) and of charlock (Sinapis arvensis L.) were buried in nylon mesh bags at two depths in four habitats in each of three geographically separated sites: Cornwall, Berkshire and Sutherland. Seeds were recovered after 12 and 24 months. Charlock exhibited much greater seed survival (average 60% surviving the first year and 32.5% surviving the second year) than oilseed rape (1.5% surviving the first year and 0.2% surviving the second) at all sites. Charlock showed higher survival at 15 cm burial than 2 cm burial at certain sites, but oilseed rape showed no depth effect. Different genetic lines of oilseed rape displayed different rates of seed survival; non-transgenic rape showed greater survival (2%) than the two transgenic lines, one developed for tolerance to the antibiotic kanamycin (0.3%) and one for tolerance to both kanamycin and the herbicide glufosinate (0.25%). The absolute and relative performances of the different genetic lines of oilseed rape were context specific, illustrating the need to test hypotheses in a wide range of ecological settings. PMID:9061957

  19. Effect of gibberellic acid and calliterpenone on plant growth attributes, trichomes, essential oil biosynthesis and pathway gene expression in differential manner in Mentha arvensis L.

    PubMed

    Bose, Subir K; Yadav, Ritesh Kumar; Mishra, Smrati; Sangwan, Rajender S; Singh, A K; Mishra, B; Srivastava, A K; Sangwan, Neelam S

    2013-05-01

    Extensive research is going on throughout the world to find out new molecules from natural sources to be used as plant growth promoter. Mentha arvensis L. is the main source of menthol rich essential oil used commercially in various food, pharmaceutical and other preparations. Experiments were conducted on field grown plants for understanding the effect of calliterpenone (CA), a stereo-isomer of abbeokutone, in comparison to gibberellic acid (GA3) on growth attributes, trichomes, essential oil biosynthesis and expression of some oil biosynthetic pathway genes. The exogenous application of CA (1 μM, 10 μM and 100 μM) was found to be better in improving plant biomass and stolon yield, leaf area, branching and leaf stem ratio than with counterpart GA3 at the same concentrations. CA treated plants showed higher glandular trichome number, density and diameter and also correlated with enhanced oil biogenetic capacity as revealed by feeding labeled (14)C-sucrose for 72 h to excised shoots. Semi-quantitative PCR analysis of key pathway genes revealed differential up regulation under CA treatments. Transcript level of menthol dehydrogenase/menthone reductase was found highly up regulated in CA treated plants with increased content of menthone and menthol in oil. These findings demonstrate that CA positively regulated the yields by enhanced branching and higher density of trichomes resulting into higher accumulation of essential oil. The results suggest CA as a novel plant derived diterpenoid with growth promoting action and opens up new possibilities for improving the crop yields and essential oil biosynthesis in qualitative and quantitative manner. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. Modelling Skylarks (Alauda arvensis) to Predict Impacts of Changes in Land Management and Policy: Development and Testing of an Agent-Based Model

    PubMed Central

    Topping, Christopher J.; Odderskær, Peter; Kahlert, Johnny

    2013-01-01

    Agent-based simulation models provide a viable approach for developing applied models of species and systems for predictive management. However, there has been some reluctance to use these models for policy applications due to complexity and the need for improved testing and communication of the models. We present the development and testing of a comprehensive model for Skylark (Alauda arvensis) in Danish agricultural landscapes. The model is part of the ALMaSS system, which considers not only individual skylarks, but also the detailed dynamic environment from which they obtain the information necessary to simulate their behaviour. Population responses emerge from individuals interacting with each other and the environment. Model development and testing was carried out using pattern-oriented modelling. The testing procedure was based on the model's ability to represent detailed real world patterns of distribution and density, reproductive performance and seasonal changes in territory numbers. Data to support this was collected over a 13-year period and comprised detailed field observations of breeding birds and intensive surveys. The model was able to recreate the real world data patterns accurately; it was also able to simultaneously fit a number of other secondary system properties which were not formally a part of the testing procedure. The correspondence of model output to real world data and sensitivity analysis are presented and discussed, and the model's description is provided in ODdox format (a formal description inter-linked to the program code). Detailed and stringent tests for model performance were carried out, and standardised model description and open access to the source code were provided to open development of the skylark model to others. Over and above documenting the utility of the model, this open process is essential to engender the user trust and ensure continued development of these comprehensive systems for applied purposes. PMID:23762430

  1. A natural formula containing lactoferrin, Equisetum arvensis, soy isoflavones and vitamin D3 modulates bone remodeling and inflammatory markers in young and aged rats.

    PubMed

    Menghini, L; Ferrante, C; Leporini, L; Recinella, L; Chiavaroli, A; Leone, S; Pintore, G; Vacca, M; Orlando, G; Brunetti, L

    2016-01-01

    A pivotal role in osteoporosis development is played by radical oxygen species (ROS), the increased production of which is related to inhibited osteoblastic activity and bone formation. A new field of research could involve medicinal plants with antioxidant and protective effects in osteoporosis. Furthermore, considering the multifactorial metabolic aspects of osteoporosis, the pharmacological association of multiple medicinal plants could improve patient response. The aim of the present study is to evaluate in vitro and in vivo the protective effects of a natural formula containing lactoferrin 12%, Equisetum arvensis ES 54%, soy isoflavones 34% and vitamin D3 0.002%, in PBMC and C2C12 cells and in the bone matrix of young (3-month-old) and aged (12-month-old) female Sprague-Dawley rats, following chronic (21 days) administration. In this context, we assayed the activities of several inflammation and bone homeostasis mediators, such as IL-6, TNFα, PGE2, osteoprotegerin, RANK, RANKL and NFkB. In vitro studies showed that natural formula (5-1000μg/ml) was able to significantly inhibit ROS and PGE2 production. In the same concentration range, the natural formula inhibited both TNFα and IL-6 gene expression. In the in vivo studies, we administered to young and aged female rats the natural formula at 5mg/rat for 21 days, finding a significant reduction in inflammatory PGE2 and NFkB activity. Nevertheless, we observed a significant increase in osteoprotegerin/RANKL ratio only in aged rats, compared to the respective control group. In conclusion, our findings corroborate the rational use of natural formula in the prevention and management of osteoporotic disease.

  2. Modelling Skylarks (Alauda arvensis) to predict impacts of changes in land management and policy: development and testing of an agent-based model.

    PubMed

    Topping, Christopher J; Odderskær, Peter; Kahlert, Johnny

    2013-01-01

    Agent-based simulation models provide a viable approach for developing applied models of species and systems for predictive management. However, there has been some reluctance to use these models for policy applications due to complexity and the need for improved testing and communication of the models. We present the development and testing of a comprehensive model for Skylark (Alauda arvensis) in Danish agricultural landscapes. The model is part of the ALMaSS system, which considers not only individual skylarks, but also the detailed dynamic environment from which they obtain the information necessary to simulate their behaviour. Population responses emerge from individuals interacting with each other and the environment. Model development and testing was carried out using pattern-oriented modelling. The testing procedure was based on the model's ability to represent detailed real world patterns of distribution and density, reproductive performance and seasonal changes in territory numbers. Data to support this was collected over a 13-year period and comprised detailed field observations of breeding birds and intensive surveys. The model was able to recreate the real world data patterns accurately; it was also able to simultaneously fit a number of other secondary system properties which were not formally a part of the testing procedure. The correspondence of model output to real world data and sensitivity analysis are presented and discussed, and the model's description is provided in ODdox format (a formal description inter-linked to the program code). Detailed and stringent tests for model performance were carried out, and standardised model description and open access to the source code were provided to open development of the skylark model to others. Over and above documenting the utility of the model, this open process is essential to engender the user trust and ensure continued development of these comprehensive systems for applied purposes.

  3. The efficacy of Mentha arvensis L. and M. piperita L. essential oils in reducing pathogenic bacteria and maintaining quality characteristics in cashew, guava, mango, and pineapple juices.

    PubMed

    de Sousa Guedes, Jossana Pereira; da Costa Medeiros, José Alberto; de Souza E Silva, Richard Sidney; de Sousa, Janaína Maria Batista; da Conceição, Maria Lúcia; de Souza, Evandro Leite

    2016-12-05

    This study evaluated the ability of the essential oil from Mentha arvensis L. (MAEO) and M. piperita L. (MPEO) to induce ≥5-log reductions in counts (CFU/mL) of E. coli, L. monocytogenes, and Salmonella enterica serovar Enteritidis in Brain-Heart Infusion broth (BHIB) and cashew, guava, mango, and pineapple juices during refrigerated storage (4±0.5°C). The effects of the incorporation of these essential oils on some physicochemical and sensory parameters of juices were also evaluated. The incorporation of 5, 2.5, 1.25, or 0.625μL/mL of MAEO in BHIB caused a ≥5-log reduction in counts of E. coli and Salmonella Enteritidis after 24h of storage; but only 5μL/mL was able to cause the same reduction in counts of L.monocytogenes. The incorporation of 10μL/mL of MPEO in BHIB caused a ≥5-log reduction in counts of E. coli, Salmonella Enteritidis, and L. monocytogenes after 24h of storage; smaller reductions were observed in BHIB containing 5, 2.5, and 1.25μL/mL of MPEO. Similar reductions were observed when the MAEO or MPEO was incorporated at the same concentrations in mango juice. The incorporation of MAEO or MPEO at all tested concentrations in cashew, guava, and pineapple juices resulted in a ≥5-log reduction in pathogen counts within 1h. The incorporation of MAEO and MPEO (0.625 and 1.25μL/mL, respectively) in fruit juices did not induce alterations in °Brix, pH, and acidity, but negatively affected the taste, aftertaste, and overall acceptance. The use of MAEO or MPEO at low concentrations could constitute an interesting tool to achieve the required 5-log reduction of pathogenic bacteria in cashew, guava, mango, and pineapple fruit juices. However, new methods combining the use of MAEO or MPEO with other technologies are necessary to reduce their negative impacts on specific sensory properties of these juices.

  4. Effect of the vesicular-arbuscular mycorrhizal (VAM) fungus Glomus fasciculatum on the essential oil yield related characters and nutrient acquisition in the crops of different cultivars of menthol mint (Mentha arvensis) under field conditions.

    PubMed

    Gupta, M L; Prasad, Arun; Ram, Muni; Kumar, Sushil

    2002-01-01

    The effects of inoculation with vesicular-arbuscular mycorrhizal (VAM) fungus Glomusfasciculatum on the root colonization, growth, essential oil yield and nutrient acquisition of three cultivars of menthol mint (Mentha arvensis); Kalka, Shivalik and Gomti, were studied under field conditions. The VAM inoculation significantly increased the root colonization, plant height, fresh herbage and dry matter yield. oil content and oil yield as compared to non-inoculated cultivars. The effect of VAM inoculation on the root colonization, growth and yield of mint was more pronounced with the cv Shivalik than the cvs Kalka and Gomati, indicating Shivalik as a highly mycorrhizal dependent genotype. VAM inoculation significantly increased the uptake of N, P and K by shoot tissues of mint, but most markedly increased the uptake of P. The VAM-inoculated mint plants depleted the available N, P and K in the rhizosphere soil as compared to non-inoculated control plants, however the extent of nutrient depletion was greater for P than N and K. We conclude that the VAM inoculation could significantly increase the root colonization, growth, essential oil yield and nutrient acquisition of mint for obtaining economic production under field conditions.

  5. Consumption of Buglossoides arvensis seed oil is safe and increases tissue long-chain n-3 fatty acid content more than flax seed oil - results of a phase I randomised clinical trial.

    PubMed

    Lefort, Natalie; LeBlanc, Rémi; Giroux, Marie-Andrée; Surette, Marc E

    2016-01-01

    Enrichment of tissues with ≥20-carbon n-3 PUFA like EPA is associated with positive cardiovascular outcomes. Stearidonic acid (SDA; 18 : 4n-3) and α-linolenic acid (ALA; 18 : 3n-3) are plant-derived dietary n-3 PUFA; however, direct comparisons of their impact on tissue n-3 PUFA content are lacking. Ahiflower(®) oil extracted from Buglossoides arvensis seeds is the richest known non-genetically modified source of dietary SDA. To investigate the safety and efficacy of dietary Ahiflower oil, a parallel-group, randomised, double-blind, comparator-controlled phase I clinical trial was performed. Diets of healthy subjects (n 40) were supplemented for 28 d with 9·1 g/d of Ahiflower (46 % ALA, 20 % SDA) or flax seed oil (59 % ALA). Blood and urine chemistries, blood lipid profiles, hepatic and renal function tests and haematology were measured as safety parameters. The fatty acid composition of fasting plasma, erythrocytes, polymorphonuclear cells and mononuclear cells were measured at baseline and after 14 and 28 d of supplementation. No clinically significant changes in safety parameters were measured in either group. Tissue ALA and EPA content increased in both groups compared with baseline, but EPA accrual in plasma and in all cell types was greater in the Ahiflower group (time × treatment interactions, P ≤ 0·01). Plasma and mononuclear cell eicosatetraenoic acid (20 : 4n-3) and docosapentaenoic acid (22 : 5n-3) content also increased significantly in the Ahiflower group compared with the flax group. In conclusion, the consumption of Ahiflower oil is safe and is more effective for the enrichment of tissues with 20- and 22-carbon n-3 PUFA than flax seed oil.

  6. Dietary Buglossoides Arvensis Oil Increases Circulating n-3 Polyunsaturated Fatty Acids in a Dose-Dependent Manner and Enhances Lipopolysaccharide-Stimulated Whole Blood Interleukin-10—A Randomized Placebo-Controlled Trial

    PubMed Central

    Lefort, Natalie; LeBlanc, Rémi; Surette, Marc E.

    2017-01-01

    Buglossoides arvensis (Ahiflower) oil is a dietary oil rich in stearidonic acid (20% SDA; 18:4 n-3). The present randomized, double blind, placebo-controlled clinical trial investigated the effects of three Ahiflower oil dosages on omega-3 polyunsaturated fatty acid (PUFA) content of plasma and mononuclear cells (MCs) and of the highest Ahiflower dosage on stimulated cytokine production in blood. Healthy subjects (n = 88) consumed 9.7 mL per day for 28 days of 100% high oleic sunflower oil (HOSO); 30% Ahiflower oil (Ahi) + 70% HOSO; 60% Ahi + 40% HOSO; and 100% Ahi. No clinically significant changes in blood and urine chemistries, blood lipid profiles, hepatic and renal function tests nor hematology were measured. Linear mixed models (repeated measures design) probed for differences in time, and time × treatment interactions. Amongst significant changes, plasma and MC eicosapentaenoic acid (EPA, 20:5 n-3) levels increased from baseline at day 28 in all Ahiflower groups (p < 0.05) and the increase was greater in all Ahiflower groups compared to the HOSO control (time × treatment interactions; p < 0.05). Similar results were obtained for α-linolenic acid (ALA, 18:3 n-3), eicosatetraenoic acid (ETA, 20:4 n-3), and docosapentaenoic acid (DPA, 22:5 n-3) content; but not docosahexaenoic acid (DHA, 22:6 n-3). Production of interleukin-10 (IL-10) was increased in the 100% Ahiflower oil group compared to 100% HOSO group (p < 0.05). IL-10 production was also increased in lipopolysaccharide (LPS)-stimulated M2-differentiated THP-1 macrophage-like cells in the presence of 20:4 n-3 or EPA (p < 0.05). Overall; this indicates that the consumption of Ahiflower oil is associated with an anti-inflammatory phenotype in healthy subjects. PMID:28287415

  7. Dietary Buglossoides Arvensis Oil Increases Circulating n-3 Polyunsaturated Fatty Acids in a Dose-Dependent Manner and Enhances Lipopolysaccharide-Stimulated Whole Blood Interleukin-10-A Randomized Placebo-Controlled Trial.

    PubMed

    Lefort, Natalie; LeBlanc, Rémi; Surette, Marc E

    2017-03-10

    Buglossoides arvensis (Ahiflower) oil is a dietary oil rich in stearidonic acid (20% SDA; 18:4 n-3). The present randomized, double blind, placebo-controlled clinical trial investigated the effects of three Ahiflower oil dosages on omega-3 polyunsaturated fatty acid (PUFA) content of plasma and mononuclear cells (MCs) and of the highest Ahiflower dosage on stimulated cytokine production in blood. Healthy subjects (n = 88) consumed 9.7 mL per day for 28 days of 100% high oleic sunflower oil (HOSO); 30% Ahiflower oil (Ahi) + 70% HOSO; 60% Ahi + 40% HOSO; and 100% Ahi. No clinically significant changes in blood and urine chemistries, blood lipid profiles, hepatic and renal function tests nor hematology were measured. Linear mixed models (repeated measures design) probed for differences in time, and time × treatment interactions. Amongst significant changes, plasma and MC eicosapentaenoic acid (EPA, 20:5 n-3) levels increased from baseline at day 28 in all Ahiflower groups (p < 0.05) and the increase was greater in all Ahiflower groups compared to the HOSO control (time × treatment interactions; p < 0.05). Similar results were obtained for α-linolenic acid (ALA, 18:3 n-3), eicosatetraenoic acid (ETA, 20:4 n-3), and docosapentaenoic acid (DPA, 22:5 n-3) content; but not docosahexaenoic acid (DHA, 22:6 n-3). Production of interleukin-10 (IL-10) was increased in the 100% Ahiflower oil group compared to 100% HOSO group (p < 0.05). IL-10 production was also increased in lipopolysaccharide (LPS)-stimulated M2-differentiated THP-1 macrophage-like cells in the presence of 20:4 n-3 or EPA (p < 0.05). Overall; this indicates that the consumption of Ahiflower oil is associated with an anti-inflammatory phenotype in healthy subjects.

  8. Surface Tension

    NASA Technical Reports Server (NTRS)

    Theissen, David B.; Man, Kin F.

    1996-01-01

    The effect of surface tension is observed inmany everyday situations. For example, a slowly leaking faucet drips because the force surface tension allows the water to cling to it until a sufficient mass of water is accumulated to break free.

  9. Surface Texture

    NASA Image and Video Library

    2005-11-09

    With all the frost gone, the south polar region is exhibiting more than just layering and surface markings. As this image from NASA 2001 Mars Odyssey spacecraft shows, the polar surface is not smooth at this resolution.

  10. Surface analysis.

    PubMed

    Kinsella, T

    2006-10-01

    Surface analysis techniques are important tools to use in the verification of surface cleanliness and medical device functionality. How these techniques can be employed and some example applications are described.

  11. Surface finishing

    NASA Technical Reports Server (NTRS)

    Kinzler, J. A.; Hefferman, J. T.; Fehrenkamp, L. G.; Lee, W. S. (Inventor)

    1980-01-01

    A surface of an article adapted for relative motion with a fluid environment is finished by coating the surface with a fluid adhesive, covering the adhesive with a sheet of flexible film material under tension on the film material whereby the tensioned film material is bonded to the surface by the adhesive.

  12. Surface mining

    Treesearch

    Robert Leopold; Bruce Rowland; Reed Stalder

    1979-01-01

    The surface mining process consists of four phases: (1) exploration; (2) development; (3) production; and (4) reclamation. A variety of surface mining methods has been developed, including strip mining, auger, area strip, open pit, dredging, and hydraulic. Sound planning and design techniques are essential to implement alternatives to meet the myriad of laws,...

  13. Surface characterization

    Treesearch

    Mandla A. Tshabalala

    2005-01-01

    Surface properties of wood play an important role when wood is used or processed into different commodities such as siding, joinery, textiles, paper, sorption media or wood composites. Thus, for example, the quality and durability of a wood coating are determined by the surface properties of the wood and the coating. The same is true for wood composites, as the...

  14. Superhydrophobic surfaces

    DOEpatents

    Wang, Evelyn N; McCarthy, Matthew; Enright, Ryan; Culver, James N; Gerasopoulos, Konstantinos; Ghodssi, Reza

    2015-03-24

    Surfaces having a hierarchical structure--having features of both microscale and nanoscale dimensions--can exhibit superhydrophobic properties and advantageous condensation and heat transfer properties. The hierarchical surfaces can be fabricated using biological nanostructures, such as viruses as a self-assembled nanoscale template.

  15. Surface Treatment

    NASA Technical Reports Server (NTRS)

    Park, Cheol (Inventor); Lowther, Sharon E. (Inventor); St.Clair, Terry L. (Inventor)

    2003-01-01

    A simple surface treatment process is provided which offers a high performance surface for a variety of applications at low cost. This novel surface treatment, which is particularly useful for Ti-6Al-4V alloys, is achieved by forming oxides on the surface with a two-step chemical process and without mechanical abrasion. First, after solvent degreasing, sulfuric acid is used to generate a fresh titanium surface. Next, an alkaline perborate solution is used to form an oxide on the surface. This acid-followed-by-base treatment is cost effective and relatively safe to use in commercial applications. In addition, it is chromium-free, and has been successfully used with a sol-gel coating to afford a strong adhesive bond that exhibits excellent durability after the bonded specimens have been subjected to a harsh 72 hour water boil immersion. Phenylethynyl containing adhesives were used to evaluate this surface treatment with a novel coupling agent containing both trialkoxysilane and phenylethynyl groups. 8 Claims, 16 Drawing Sheets

  16. Describing Surfaces.

    DTIC Science & Technology

    1985-01-01

    constant, then it is made explicit. For example, the asymptote that marks the smooth join of the bulb and the stem of the lightbulb in Figure 1, as...illustrates the representation we are aiming at. The stem of the lightbulb is determined to be cylindrical, because it is ruled and because it is a surface...and threaded end. This distinguishes the diameters of each that are collinear with the stem axis, showing ,4 that the lightbulb is a surface of

  17. Martian surface

    SciTech Connect

    Carr, M.H.

    1987-03-01

    The surface of Mars is characterized on the basis of reformatted Viking remote-sensing data, summarizing results published during the period 1983-1986. Topics examined include impact craters, ridges and faults, volcanic studies (modeling of surface effects on volcanic activity, description and interpretation of volcanic features, and calculations on lava-ice interactions), the role of liquid water on Mars, evidence for abundant ground ice at high latitudes, water-cycle modeling, and the composition and dynamics of Martian dust.

  18. Bioassay of Surface Quality/Chesapeake Bay, Maryland

    DTIC Science & Technology

    1995-02-01

    Lycopus rubellus 0.384c2 .8462 0.0 0P 62 Mentha spicata 0.38462 3.8462 0.0 063 Phryma leftostachya 0.38462 3.8462 0.0 0CP 64 * Potamogeton diversifolius...33.2 90 P 157 Commelina communis 6.769 11.538 9.7 50 a P 158 Mentha arvensis 7.038 19.231 1.5 10 CP2 .5 Nasturtium officianale 7.077 26 .923 0.0 0 p

  19. Surface Tension

    SciTech Connect

    2011-01-01

    Surface tension in the kitchen sink. At Berkeley Lab's Molecular Foundry, scientists study surface tension to understand how molecules "self-assemble." The coin trick in the video uses the re-arrangement of water molecules to seemingly create order out of disorder. The same principle can be used to create order in otherwise hard-to-handle nano materials. Scientists can then transfer these ordered materials onto surfaces by dipping them through the air-water interface, or (as we've recently shown) squeeze them so that they collapse into the water as two-molecule-thick nano sheets. http://newscenter.lbl.gov/feature-stories/2011/10/17/shaken-not-stirred/

  20. Ice Surfaces

    NASA Astrophysics Data System (ADS)

    Shultz, Mary Jane

    2017-05-01

    Ice is a fundamental solid with important environmental, biological, geological, and extraterrestrial impact. The stable form of ice at atmospheric pressure is hexagonal ice, Ih. Despite its prevalence, Ih remains an enigmatic solid, in part due to challenges in preparing samples for fundamental studies. Surfaces of ice present even greater challenges. Recently developed methods for preparation of large single-crystal samples make it possible to reproducibly prepare any chosen face to address numerous fundamental questions. This review describes preparation methods along with results that firmly establish the connection between the macroscopic structure (observed in snowflakes, microcrystallites, or etch pits) and the molecular-level configuration (detected with X-ray or electron scattering techniques). Selected results of probing interactions at the ice surface, including growth from the melt, surface vibrations, and characterization of the quasi-liquid layer, are discussed.

  1. Surface Diversity

    NASA Image and Video Library

    2016-03-17

    This enhanced color view of Pluto's surface diversity was created by merging Ralph/Multispectral Visible Imaging Camera (MVIC) color imagery (650 meters per pixel) with Long Range Reconnaissance Imager panchromatic imagery (230 meters per pixel). At lower right, ancient, heavily cratered terrain is coated with dark, reddish tholins. At upper right, volatile ices filling the informally named Sputnik Planum have modified the surface, creating a chaos-like array of blocky mountains. Volatile ice also occupies a few nearby deep craters, and in some areas the volatile ice is pocked with arrays of small sublimation pits. At left, and across the bottom of the scene, gray-white CH4 ice deposits modify tectonic ridges, the rims of craters, and north-facing slopes. The scene in this image is 260 miles (420 kilometers) wide and 140 miles (225 kilometers) from top to bottom; north is to the upper left. http://photojournal.jpl.nasa.gov/catalog/PIA20534

  2. Surface Structure and Surface Order

    DTIC Science & Technology

    1991-05-15

    dynamics simulations shown in fig. 6.22, show that surface melting is expected to be Figure 6.22. A molecular dynamics simulation for a two...to determine the critical exponents in Table II. Figure 6.22. A molecular dynamics simulation for a two-dimensional slab showing trajectories of the...Their calculations confirm that the relaxation should be oscillatory [7]. 6.1 b. Structures Due to Adsorption and Segregation When atoms or molecules

  3. Surface mining

    SciTech Connect

    Not Available

    1989-06-01

    This paper reports on a GAO study of attorney and expert witness fees awarded as a result of litigation brought under the Surface Mining Control and Reclamation Act. As of March 24, 1989, a total of about $1.4 million had been awarded in attorney fees and expenses - about $1.3 subject to the provisions of the Employee Retirement Income Security Act, a comparison of its features with provisions of ERISA showed that the plan differed from ERISA provisions in areas such as eligibility, funding, and contribution limits.

  4. Surface Dissection

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03290 Surface Dissection

    At the southern end of Echus Cansma this dissected surface and mega-gullies occur.

    Image information: VIS instrument. Latitude -1.1N, Longitude 278.8E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Oxide surfaces.

    PubMed

    Willmott, Phil

    2008-07-02

    Although the history of metal oxides and their surfaces goes back several decades to landmark studies, such as Mott and Peierls' explanation of electrical insulation in materials that are predicted in band theory to be conducting, or the observation by Morin of the superfast metal-to-insulator transition in vanadium dioxide, it is only in the last two decades that the world of condensed matter physics has become increasingly dominated by research into complex metal oxides. This has been driven most notably by an attempt to better understand and describe the fundamental physical processes behind their seemingly endless spectrum of properties, which in turn has also led to the discovery of novel phenomena, most prominently demonstrated by the discovery of high-temperature superconductivity in 1986, colossal magnetoresistance in 1994, and most recently, the formation of a two-dimensional conducting layer at the interface between two band insulators in 2004. One important reason why metal oxides, particularly in the form of thin films, have become such a popular subject for basic condensed matter research is that they offer a uniquely versatile materials base for the development of novel technologies. They owe this versatility both to the many different elemental combinations that lead to structurally similar forms, and also to the fact that in many cases, the strong interaction between the valence electrons means that there is a subtle interplay between structure and magnetic and electronic properties. This aspect has led in recent years to the birth or renaissance of research fields such as spintronics, orbital ordering, and multiferroics. Surfaces and interfaces are especially interesting in these strongly-correlated electron systems, where the rearrangement of electrical charge resulting from a minimization of surface or interfacial energy can have unexpected and often exciting consequences. Indeed, as the drive to miniaturize devices well below the micron size

  6. Generalized offset surfaces of cylindrical surfaces

    NASA Astrophysics Data System (ADS)

    Georgiev, Georgi Hristov

    2016-12-01

    Cylindrical surfaces play an important role in geometric modeling and architecture. In this paper, we describe a way for constructing a new cylindrical surface from a given cylindrical surface. Our approach is based on the differential geometry of cylindrical surfaces and a generalization of the notion of offset surface. We examine the case of a similarity offset of an arbitrary cylindrical surface which is closely related to direct similarities of Euclidean 3-space. Some illustrative examples are included.

  7. Unstructured surface grid generation

    NASA Technical Reports Server (NTRS)

    Samareh-Abolhassani, Jamshid

    1993-01-01

    Viewgraphs on unstructured surface grid generation are presented. Topics covered include: requirements for curves, surfaces, solids, and text; surface approximation; triangulation; advancing; projection; mapping; and parametric curves.

  8. Toroidal surfaces compared with spherocylindrical surfaces

    NASA Astrophysics Data System (ADS)

    Malacara-Doblado, Daniel; Malacara-Hernandez, Daniel; Garcia-Marquez, Jorge L.

    1995-08-01

    Toroidal and sphero-cylindrical optical surfaces are two different kinds of surfaces (Menchaca and Malacara, 1986), but they are almost identical in the vicinity of the optical axis. The separation between these two surfaces increases when the distance to the optical axis increases. In this work the separation between these two surfaces outside of the central region is analytically studied.

  9. Brain surface parameterization using Riemann surface structure.

    PubMed

    Wang, Yalin; Gu, Xianfeng; Hayashi, Kiralee M; Chan, Tony F; Thompson, Paul M; Yau, Shing-Tung

    2005-01-01

    We develop a general approach that uses holomorphic 1-forms to parameterize anatomical surfaces with complex (possibly branching) topology. Rather than evolve the surface geometry to a plane or sphere, we instead use the fact that all orientable surfaces are Riemann surfaces and admit conformal structures, which induce special curvilinear coordinate systems on the surfaces. Based on Riemann surface structure, we can then canonically partition the surface into patches. Each of these patches can be conformally mapped to a parallelogram. The resulting surface subdivision and the parameterizations of the components are intrinsic and stable. To illustrate the technique, we computed conformal structures for several types of anatomical surfaces in MRI scans of the brain, including the cortex, hippocampus, and lateral ventricles. We found that the resulting parameterizations were consistent across subjects, even for branching structures such as the ventricles, which are otherwise difficult to parameterize. Compared with other variational approaches based on surface inflation, our technique works on surfaces with arbitrary complexity while guaranteeing minimal distortion in the parameterization. It also offers a way to explicitly match landmark curves in anatomical surfaces such as the cortex, providing a surface-based framework to compare anatomy statistically and to generate grids on surfaces for PDE-based signal processing.

  10. Surface stress of stepped chiral metal surfaces.

    PubMed

    Blanco-Rey, M; Pratt, S J; Jenkins, S J

    2009-01-16

    The use of surface stress as a physical probe for examining chiral effects in surfaces is proposed. First-principles calculations of the surface stress in stepped achiral and chiral bcc metal surfaces (Fe, Mo, and W) are presented. When no mirror symmetry is present, principal stress orientations are unconstrained; nevertheless, we find that the stress is smoothly varying along a suitably chosen stereographic zone of surfaces. Stress ellipses for Fe differ qualitatively from those of Mo and W, suggesting that its surface stress has a distinct origin.

  11. Aerodynamic properties of wild mustard (Sinapis arvensis L.) seed for separation from canola.

    PubMed

    Shahbazi, Feizollah

    2013-04-01

    Wild mustard seed is similar in size and shape to canola seed and can be separated by pneumatic means if the aerodynamic properties of these two materials are well known. The objective of this study was evaluation of the aerodynamic properties of canola and wild mustard seeds as a function of moisture content from 5% to 20% (w.b). The results showed that the terminal velocity of canola seeds increased, following a polynomial relationship from 5.401 to 6.566 m s(-1), as the moisture content increased from 5% to 20%. Over this same moisture content range the terminal velocity of wild mustard seeds varied from 4.276 to 5.433 m s(-1). The drag coefficient of canola and wild mustard seeds decreased linearly from 1.062 to 0.646 and from 1.432 to 0.928, respectively, as moisture content increased from 5% to 20%. Analysis of variance showed that there was a significant difference between the terminal velocity and drag coefficient of canola and wild mustard seed at a 1% probability level. The results suggest that aerodynamic separation of wild mustard seed from canola is possible. Moisture content had a significant effect on the terminal velocity and drag coefficient of seeds. © 2012 Society of Chemical Industry.

  12. Effect of foliar treatments on distribution of /sup 14/C-glyphosate in Convolvulus arvensis L

    SciTech Connect

    Lauridson, T.C.

    1986-01-01

    Field bindweed is a perennial weed which produces shoots from buds on its roots. Herbicides, such as glyphosate (N-(phosphonomethyl)glycine) used for control of field bindweed usually do not kill all shoot buds on the roots, thus field bindweed often reinfests areas within 3 to 6 weeks of treatment. This dissertation deals with the development of a technique to change glyphosate distribution in field bindweed roots and could result in less shoot regrowth after glyphosate application. In field studies eight plant growth regulators were applied in September, 3 days before 2.24 kg/ha of 2.4-D((2,4-dichlorophenoxy) acetic acid) or 1.68 kg/ha of glyphosate. Eight months later, regrowth of shoots was least where glyphosate was applied at 0.028 kg/ha as a pretreatment, followed by a standard rate of 1.68 kg/ha. In subsequent greenhouse studies, typical patterns of shoot growth and /sup 14/C-glyphosate distribution in isolated root sections taken from 15-week-old intact plants were determined. In subsequent growth chamber studies, plants were decapitated to observe the effect of shoot apical dominance on /sup 14/C-glyphosate translocation. After /sup 14/C-glyphosate was applied, intact plants had about twice as much /sup 14/C in distal root sections as in proximal or middle root sections. Decapitated plants had more /sup 14/C in proximal and middle root sections than in distal sections, and about twice as much /sup 14/C was translocated to roots of decapitated plants than intact plants. Eight concentrations of 2,4,-D or glyphosate from 1 to 5000 ppm were applied in logarithmic series to 6-week old plants.

  13. Computer aided surface representation

    SciTech Connect

    Barnhill, R.E.

    1990-02-19

    The central research problem of this project is the effective representation, computation, and display of surfaces interpolating to information in three or more dimensions. If the given information is located on another surface, then the problem is to construct a surface defined on a surface''. Sometimes properties of an already defined surface are desired, which is geometry processing''. Visualization of multivariate surfaces is possible by means of contouring higher dimensional surfaces. These problems and more are discussed below. The broad sweep from constructive mathematics through computational algorithms to computer graphics illustrations is utilized in this research. The breadth and depth of this research activity makes this research project unique.

  14. Fast Disinfecting Antimicrobial Surfaces

    PubMed Central

    Madkour, Ahmad E.; Dabkowski, Jeffery M.; Nüsslein, Klaus; Tew, Gregory N.

    2013-01-01

    Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the “grafting from” technique. Surface initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied. PMID:19177651

  15. Fast disinfecting antimicrobial surfaces.

    PubMed

    Madkour, Ahmad E; Dabkowski, Jeffery M; Nusslein, Klaus; Tew, Gregory N

    2009-01-20

    Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the "grafting from" technique. Surface-initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied.

  16. Biocompatible implant surface treatments.

    PubMed

    Pattanaik, Bikash; Pawar, Sudhir; Pattanaik, Seema

    2012-01-01

    Surface plays a crucial role in biological interactions. Surface treatments have been applied to metallic biomaterials in order to improve their wear properties, corrosion resistance, and biocompatibility. A systematic review was performed on studies investigating the effects of implant surface treatments on biocompatibility. We searched the literature using PubMed, electronic databases from 1990 to 2009. Key words such as implant surface topography, surface roughness, surface treatment, surface characteristics, and surface coatings were used. The search was restricted to English language articles published from 1990 to December 2009. Additionally, a manual search in the major dental implant journals was performed. When considering studies, clinical studies were preferred followed by histological human studies, animal studies, and in vitro studies. A total of 115 articles were selected after elimination: clinical studies, 24; human histomorphometric studies, 11; animal histomorphometric studies, 46; in vitro studies, 34. The following observations were made in this review: · The focus has shifted from surface roughness to surface chemistry and a combination of chemical manipulations on the porous structure. More investigations are done regarding surface coatings. · Bone response to almost all the surface treatments was favorable. · Future trend is focused on the development of osteogenic implant surfaces. Limitation of this study is that we tried to give a broader overview related to implant surface treatments. It does not give any conclusion regarding the best biocompatible implant surface treatment investigated till date. Unfortunately, the eventually selected studies were too heterogeneous for inference of data.

  17. Designing Superoleophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Tuteja, Anish; Choi, Wonjae; Ma, Minglin; Mabry, Joseph M.; Mazzella, Sarah A.; Rutledge, Gregory C.; McKinley, Gareth H.; Cohen, Robert E.

    2007-12-01

    Understanding the complementary roles of surface energy and roughness on natural nonwetting surfaces has led to the development of a number of biomimetic superhydrophobic surfaces, which exhibit apparent contact angles with water greater than 150 degrees and low contact angle hysteresis. However, superoleophobic surfaces—those that display contact angles greater than 150 degrees with organic liquids having appreciably lower surface tensions than that of water—are extremely rare. Calculations suggest that creating such a surface would require a surface energy lower than that of any known material. We show how a third factor, re-entrant surface curvature, in conjunction with chemical composition and roughened texture, can be used to design surfaces that display extreme resistance to wetting from a number of liquids with low surface tension, including alkanes such as decane and octane.

  18. Nanofluids mediating surface forces.

    PubMed

    Pilkington, Georgia A; Briscoe, Wuge H

    2012-11-01

    Fluids containing nanostructures, known as nanofluids, are increasingly found in a wide array of applications due to their unique physical properties as compared with their base fluids and larger colloidal suspensions. With several tuneable parameters such as the size, shape and surface chemistry of nanostructures, as well as numerous base fluids available, nanofluids also offer a new paradigm for mediating surface forces. Other properties such as local surface plasmon resonance and size dependent magnetism of nanostructures also present novel mechanisms for imparting tuneable surface interactions. However, our fundamental understanding, experimentally and theoretically, of how these parameters might affect surface forces remains incomplete. Here we review recent results on equilibrium and dynamic surface forces between macroscopic surfaces in nanofluids, highlighting the overriding trends in the correlation between the physical parameters that characterise nanofluids and the surface forces they mediate. We also discuss the challenges that confront existing surface force knowledge as a result of this new paradigm.

  19. Mechanics of active surfaces

    NASA Astrophysics Data System (ADS)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  20. Computer aided surface representation

    SciTech Connect

    Barnhill, R E

    1987-11-01

    The aims of this research are the creation of new surface forms and the determination of geometric and physical properties of surfaces. The full sweep from constructive mathematics through the implementation of algorithms and the interactive computer graphics display of surfaces is utilized. Both three-dimensional and multi- dimensional surfaces are considered. Particular emphasis is given to the scientific computing solution of Department of Energy problems. The methods that we have developed and that we are proposing to develop allow applications such as: Producing smooth contour maps from measured data, such as weather maps. Modeling the heat distribution inside a furnace from sample measurements. Terrain modeling based on satellite pictures. The investigation of new surface forms includes the topics of triangular interpolants, multivariate interpolation, surfaces defined on surfaces and monotone and/or convex surfaces. The geometric and physical properties considered include contours, the intersection of surfaces, curvatures as a interrogation tool, and numerical integration.

  1. The Goldilocks Surface

    PubMed Central

    Vogler, Erwin A.

    2011-01-01

    A minimum in the biological response to materials that is observed to occur within a narrow surface energy range is related to the properties of water at these biology-contacting surfaces. Wetting energetics are calculated using a published theory from which it is further estimated that water molecules bind to these special surfaces through a single hydrogen bond, leaving three other hydrogen bonds to interact with proximal water molecules. It is concluded that, at this Goldilocks Surface, the local chemical environment of surface-bound water is nearly identical to that experienced in bulk water; neither deprived of hydrogen bond opportunities, as it is in contact with a more hydrophobic surface, nor excessively hydrogen bonded to a more hydrophilic surface. A minimum in the biological response occurs because water vicinal (near) to the Goldilocks Surface is not chemically different than bulk water. A more precise definition of the relative terms hydrophobic and hydrophilic for use in biomaterials becomes evident from calculations: > 1.3 kJ/mole-of-surface-sites is expended in wetting a hydrophilic surface whereas < 1.3 kJ/mole-of-surface-sites is expended in wetting hydrophobic surfaces; hydrophilic surfaces wet with > 1 hydrogen bond per water molecule whereas hydrophobic surfaces wet with < 1 hydrogen bond per water molecule. PMID:21684003

  2. Surface characteristics of thermally treated titanium surfaces

    PubMed Central

    Lee, Yang-Jin; Cui, De-Zhe; Jeon, Ha-Ra; Chung, Hyun-Ju; Park, Yeong-Joon; Kim, Ok-Su

    2012-01-01

    Purpose The characteristics of oxidized titanium (Ti) surfaces varied according to treatment conditions such as duration time and temperature. Thermal oxidation can change Ti surface characteristics, which affect many cellular responses such as cell adhesion, proliferation, and differentiation. Thus, this study was conducted to evaluate the surface characteristics and cell response of thermally treated Ti surfaces. Methods The samples were divided into 4 groups. Control: machined smooth titanium (Ti-S) was untreated. Group I: Ti-S was treated in a furnace at 300℃ for 30 minutes. Group II: Ti-S was treated at 500℃ for 30 minutes. Group III: Ti-S was treated at 750℃ for 30 minutes. A scanning electron microscope, atomic force microscope, and X-ray diffraction were used to assess surface characteristics and chemical composition. The water contact angle and surface energy were measured to assess physical properties. Results The titanium dioxide (TiO2) thickness increased as the treatment temperature increased. Additional peaks belonging to rutile TiO2 were only found in group III. The contact angle in group III was significantly lower than any of the other groups. The surface energy significantly increased as the treatment temperature increased, especially in group III. In the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, after 24 hours of incubation, the assessment of cell viability showed that the optical density of the control had a higher tendency than any other group, but there was no significant difference. However, the alkaline phosphatase activity increased as the temperature increased, especially in group III. Conclusions Consequently, the surface characteristics and biocompatibility increased as the temperature increased. This indicates that surface modification by thermal treatment could be another useful method for medical and dental implants. PMID:22803009

  3. Designing bioinspired superoleophobic surfaces

    NASA Astrophysics Data System (ADS)

    Brown, Philip S.; Bhushan, Bharat

    2016-01-01

    Nature provides a range of functional surfaces, for example, water-repellent or superhydrophobic surfaces, most common among them the lotus leaf. While water-repellency is widespread in nature, oil-repellency is typically limited to surfaces submerged in water, such as fish scales. To achieve oleophobicity in air, inspiration must be taken from natural structures and chemistries that are not readily available in nature need to be introduced. Researchers usually turn to fluorinated materials to provide the low surface energy that, when combined with bioinspired surface topography, is the key to unlocking oil-repellency. This review presents the state-of-the-art in the fabrication of superoleophobic surfaces.

  4. Fluorinated silica microchannel surfaces

    DOEpatents

    Kirby, Brian J.; Shepodd, Timothy Jon

    2005-03-15

    A method for surface modification of microchannels and capillaries. The method produces a chemically inert surface having a lowered surface free energy and improved frictional properties by attaching a fluorinated alkane group to the surface. The coating is produced by hydrolysis of a silane agent that is functionalized with either alkoxy or chloro ligands and an uncharged C.sub.3 -C.sub.10 fluorinated alkane chain. It has been found that the extent of surface coverage can be controlled by controlling the contact time from a minimum of about 2 minutes to a maximum of 120 minutes for complete surface coverage.

  5. Laser Surface Profiler

    SciTech Connect

    Butler, M.A.; Chu, A.

    1998-11-24

    By accurately measuring the angle of reflection of a laser beam incident on a reflective surface with a position sensitive detector, changes in the surface normal direction (slope of the surface) can be determined directly. An instrument has been built that makes repeated measurements over the surface, and uses this data to produce a grayscale image of the slope. The resolution of this system to changes in the surface normal direction is found to be better than 0.01 degrees. By focusing the Iaser beam to achieve a lateral resolution of 5 pm, the resolvable surface height change due to a variation in slope is estimated to be <1 nm.

  6. Extremal surface barriers

    NASA Astrophysics Data System (ADS)

    Engelhardt, Netta; Wall, Aron C.

    2014-03-01

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy.

  7. PREFACE: Vibrations at surfaces Vibrations at surfaces

    NASA Astrophysics Data System (ADS)

    Rahman, Talat S.

    2011-12-01

    This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of

  8. Anisotropic Artificial Impedance Surfaces

    NASA Astrophysics Data System (ADS)

    Quarfoth, Ryan Gordon

    Anisotropic artificial impedance surfaces are a group of planar materials that can be modeled by the tensor impedance boundary condition. This boundary condition relates the electric and magnetic field components on a surface using a 2x2 tensor. The advantage of using the tensor impedance boundary condition, and by extension anisotropic artificial impedance surfaces, is that the method allows large and complex structures to be modeled quickly and accurately using a planar boundary condition. This thesis presents the theory of anisotropic impedance surfaces and multiple applications. Anisotropic impedance surfaces are a generalization of scalar impedance surfaces. Unlike the scalar version, anisotropic impedance surfaces have material properties that are dependent on the polarization and wave vector of electromagnetic radiation that interacts with the surface. This allows anisotropic impedance surfaces to be used for applications that scalar surfaces cannot achieve. Three of these applications are presented in this thesis. The first is an anisotropic surface wave waveguide which allows propagation in one direction, but passes radiation in the orthogonal direction without reflection. The second application is a surface wave beam shifter which splits a surface wave beam in two directions and reduces the scattering from an object placed on the surface. The third application is a patterned surface which can alter the scattered radiation pattern of a rectangular shape. For each application, anisotropic impedance surfaces are constructed using periodic unit cells. These unit cells are designed to give the desired surface impedance characteristics by modifying a patterned metallic patch on a grounded dielectric substrate. Multiple unit cell geometries are analyzed in order to find the setup with the best performance in terms of impedance characteristics and frequency bandwidth.

  9. Durable low surface-energy surfaces

    NASA Technical Reports Server (NTRS)

    Willis, Paul B. (Inventor); McElroy, Paul M. (Inventor); Hickey, Gregory H. (Inventor)

    1993-01-01

    A formulation for forming a low surface-energy surface on a substrate having (i) a fluoroalkyl silane having a low surface energy part, (ii) a liquid crystal silane operable for enhancing the orientation of the molecules of the fluoroalkyl silane and for crosslinking with the fluoroalkyl silane, and, (iii) a transport medium for applying the fluoroalkyl silane and the liquid crystal silane to the surface of a substrate. In one embodiment the formulation can includes a crosslinking agent for crosslinking the fluoroalkyl silane. In another embodiment the formulation has a condensation catalyst for enhancing chemical bonding of the fluoroalkyl silane to the substrate. The transport medium can be an alcohol such as methanol or ethanol.

  10. Demonstration of Surface Tension.

    ERIC Educational Resources Information Center

    Rosenthal, Andrew J.

    2001-01-01

    Surface tension is a fundamental obstacle in the spontaneous formation of bubbles, droplets, and crystal nuclei in liquids. Describes a simple overhead projector demonstration that illustrates the power of surface tension that can prevent so many industrial processes. (ASK)

  11. On neutron surface waves

    SciTech Connect

    Ignatovich, V. K.

    2009-01-15

    It is shown that neutron surface waves do not exist. The difference between the neutron wave mechanics and the wave physics of electromagnetic and acoustic processes, which allows the existence of surface waves, is analyzed.

  12. EPA Permeable Surface Research

    EPA Science Inventory

    EPA recognizes permeable surfaces as an effective post-construction infiltration-based Best Management Practice to mitigate the adverse effects of stormwater runoff. The professional user community conceptually embraces permeable surfaces as a tool for making runoff more closely...

  13. Rilles on Vesta Surface

    NASA Image and Video Library

    2011-10-24

    This image from NASA Dawn spacecraft shows small rilles scars on asteroid Vesta surface, mostly concentrated in the right half image, presumably due to impacts throwing out boulders, which crash across the surface scouring the rilles as they go.

  14. Demonstration of Surface Tension.

    ERIC Educational Resources Information Center

    Rosenthal, Andrew J.

    2001-01-01

    Surface tension is a fundamental obstacle in the spontaneous formation of bubbles, droplets, and crystal nuclei in liquids. Describes a simple overhead projector demonstration that illustrates the power of surface tension that can prevent so many industrial processes. (ASK)

  15. Nonlinear thermal surface waves

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.; Stenflo, L.

    1984-09-01

    It is shown that density profile modifications near a plasma surface can survive at moving localized spots because of the radiation pressure of leaking wave field fluctuations. The properties of these luminous surface cavitons are studied.

  16. EPA Permeable Surface Research

    EPA Science Inventory

    EPA recognizes permeable surfaces as an effective post-construction infiltration-based Best Management Practice to mitigate the adverse effects of stormwater runoff. The professional user community conceptually embraces permeable surfaces as a tool for making runoff more closely...

  17. Surface flashover of insulators

    SciTech Connect

    Miller, H.C.

    1988-08-31

    This paper reviews surface flashover (i.e., voltage breakdown along the surfaces of insulators), primarily in vacuum, although some comments are made about surface/flashover in high pressure gases. Theories and models relating to surface flashover are discussed, along with pertinent experimental results. Also, some suggestions are made regarding how to choose the material, geometry, and processing when selecting an insulator for a particular application.

  18. Magnetically driven surface mixing

    NASA Astrophysics Data System (ADS)

    Belkin, M.; Snezhko, A.; Aranson, I. S.; Kwok, W.-K.

    2009-07-01

    Magnetic microparticles suspended on the surface of liquid and energized by vertical alternating magnetic field exhibit complex collective behavior. Various immobile and self-propelled self-assembled structures have been observed. Here, we report on experimental studies of mixing and surface diffusion processes in this system. We show that the pattern-induced surface flows have properties of quasi-two-dimensional turbulence. Correspondingly, the surface advection of tracer particle exhibits properties of Brownian diffusion.

  19. Surface Functionalized Polyethylene Film.

    DTIC Science & Technology

    1986-06-01

    functionality into this oxidized surface layer. 2) Explored new techniques for analyzing the surfaces of organic polymeric solids. Contact angle titration...the study of the contact angle of water on organic solids as a function of pH--has proved particularly useful and extremely surface sensitive. 3

  20. Triangular bubble spline surfaces

    PubMed Central

    Kapl, Mario; Byrtus, Marek; Jüttler, Bert

    2011-01-01

    We present a new method for generating a Gn-surface from a triangular network of compatible surface strips. The compatible surface strips are given by a network of polynomial curves with an associated implicitly defined surface, which fulfill certain compatibility conditions. Our construction is based on a new concept, called bubble patches, to represent the single surface patches. The compatible surface strips provide a simple Gn-condition between two neighboring bubble patches, which are used to construct surface patches, connected with Gn-continuity. For n≤2, we describe the obtained Gn-condition in detail. It can be generalized to any n≥3. The construction of a single surface patch is based on Gordon–Coons interpolation for triangles. Our method is a simple local construction scheme, which works uniformly for vertices of arbitrary valency. The resulting surface is a piecewise rational surface, which interpolates the given network of polynomial curves. Several examples of G0, G1 and G2-surfaces are presented, which have been generated by using our method. The obtained surfaces are visualized with reflection lines to demonstrate the order of smoothness. PMID:22267872

  1. Surface drip irrigation

    USDA-ARS?s Scientific Manuscript database

    For many years, surface drip irrigation has been used to irrigation high value vegetable crops. In recent years, surface drip of row crops has been increasing throughout the United States. Surface drip irrigation can precisely deliver water and nutrients to the crop root zone. This article provides ...

  2. Response Surface Methodology

    DTIC Science & Technology

    2004-10-01

    methods . All three of these topics are usually combined into Response Surface Methodology (RSM). Also the experimenter may encounter situations where...TITLE AND SUBTITLE Response Surface Methodology 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...18 Keywords: Response Surface Methodology (RSM), regression analysis, linear

  3. Minimal surfaces over stars

    NASA Astrophysics Data System (ADS)

    McDougall, Jane; Schaubroeck, Lisbeth

    2008-04-01

    A JS surface is a minimal graph over a polygonal domain that becomes infinite in magnitude at the domain boundary. Jenkins and Serrin characterized the existence of these minimal graphs in terms of the signs of the boundary values and the side-lengths of the polygon. For a convex polygon, there can be essentially only one JS surface, but a non-convex domain may admit several distinct JS surfaces. We consider two families of JS surfaces corresponding to different boundary values, namely JS0 and JS1, over domains in the form of regular stars. We give parameterizations for these surfaces as lifts of harmonic maps, and observe that all previously constructed JS surfaces have been of type JS0. We give an example of a JS1 surface that is a new complete embedded minimal surface generalizing Scherk's doubly periodic surface, and show also that the JS0 surface over a regular convex 2n-gon is the limit of JS1 surfaces over non-convex stars. Finally we consider the construction of other JS surfaces over stars that belong neither to JS0 nor to JS1.

  4. Surface Conductive Glass.

    ERIC Educational Resources Information Center

    Tanaka, John; Suib, Steven L.

    1984-01-01

    Discusses the properties of surface-conducting glass and the chemical nature of surface-conducting stannic (tin) oxide. Also provides the procedures necessary for the preparation of surface-conducting stannic oxide films on glass substrates. The experiment is suitable for the advanced inorganic chemistry laboratory. (JN)

  5. Sulfide Mineral Surfaces

    SciTech Connect

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

  6. The neutral surface layer above rough surfaces

    NASA Astrophysics Data System (ADS)

    Smedman, Ann-Sofi; Sahlee, Erik

    2014-05-01

    It is generally accepted that turbulent fluxes (momentum and scalar fluxes) are approx. constant with height above horizontal surfaces with low roughness. But what will happen when the roughness sub-layer is large as found over cities, forests and rough seas? In a study of the kinematic structure of the near neutral atmospheric surface layer, Högström, Hunt and Smedman, 2002, it was demonstrated that a model with detached eddies from above the surface layer impinging on to the surface (Hunt and Morison, 2000) could explain some of the observed features in the neutral atmospheric boundary layer. Thus the detached eddy model proved successful in explaining the dynamic structure of the near neutral atmospheric surface layer, especially the shape of the spectra of the wind components and scalars and corresponding fluxes. Here we make the hypothesis that the detached-eddy model can also be used to explain the experimental results related to the 3-dimensional turbulence structure above rough surfaces. Measurements are taken both over land (grass and forest) and over sea (Baltic Sea and hurricane Fabian in the Atlantic) above the roughness sub-layer. Analysis of the turbulence structure shows a striking similarity between the different sites. Hunt, J.C.R and Morrison, J.F., 2000: Eddy structure in turbulent boundary layers, Euro. J. Mech. B-Fluids, 19, 673-694. Högström, U., Hunt, J.C.R., and Smedman, A., 2002: Theory and measurements for turbulence spectra and variances in the atmospheric neutral surface layer, Bound.-Layer Meteorol., 103,101-124.

  7. Solitary surface waves

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.; Stenflo, L.

    1982-06-01

    Surface solitons excited at the edge of a plasma sheet can propagate across the sheet along its surface and, depending on the parameters chosen, collide with surface solitons at the edge. The strong electric field created in such a collision may produce a spot of light. Attention is given to surface solitons on a semi-infinite plasma, using cold electron plasma equations. Because all characteristic times of the processes in question are much smaller than the inverse ion plasma frequency, the ions may be regarded as immobile. This situation is relevant to a plasma bounded by a dielectric which prevents distortion of the surface.

  8. Surface cleanliness measurement procedure

    DOEpatents

    Schroder, Mark Stewart; Woodmansee, Donald Ernest; Beadie, Douglas Frank

    2002-01-01

    A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

  9. Visual Inspection of Surfaces

    NASA Technical Reports Server (NTRS)

    Hughes, David; Perez, Xavier

    2007-01-01

    This presentation evaluates the parameters that affect visual inspection of cleanliness. Factors tested include surface reflectance, surface roughness, size of the largest particle, exposure time, inspector and distance from sample surface. It is concluded that distance predictions were not great, particularly because the distance at which contamination is seen may depend on more variables than those tested. Most parameters estimates had confidence of 95% or better, except for exposure and reflectance. Additionally, the distance at which surface is visibly contaminated decreases with increasing reflectance, roughness, and exposure. The distance at which the surface is visually contaminated increased with the largest particle size. These variables were only slightly affected the observer.

  10. Surface freezing of water.

    PubMed

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

  11. Superenantioselective chiral surface explosions.

    PubMed

    Gellman, Andrew J; Huang, Ye; Feng, Xu; Pushkarev, Vladimir V; Holsclaw, Brian; Mhatre, Bharat S

    2013-12-26

    Chiral inorganic materials predated life on Earth, and their enantiospecific surface chemistry may have played a role in the origins of biomolecular homochirality. However, enantiospecific differences in the interaction energies of chiral molecules with chiral surfaces are small and typically lead to modest enantioselectivities in adsorption, catalysis, and chemistry on chiral surfaces. To yield high enantioselectivities, small energy differences must be amplified by reaction mechanisms such as autocatalytic surface explosions which have nonlinear kinetics. Herein, we report the first observations of superenantiospecificity resulting from an autocatalytic surface explosion reaction of a chiral molecule on a naturally chiral surface. R,R- and S,S-tartaric acid decompose via a vacancy-mediated surface explosion mechanism on Cu single crystal surfaces. When coupled with surface chirality, this leads to decomposition rates that exhibit extraordinarily high enantiospecificity. On the enantiomorphs of naturally chiral Cu(643)(R&S), Cu(17,5,1)(R&S), Cu(531)(R&S) and Cu(651)(R&S) single crystal surfaces, R,R- and S,S-tartaric acid exhibit enantiospecific decomposition rates that differ by as much as 2 orders of magnitude, despite the fact that the effective rates constants for decomposition differ by less than a factor of 2.

  12. Periodic minimal surfaces

    NASA Astrophysics Data System (ADS)

    Mackay, Alan L.

    1985-04-01

    A minimal surface is one for which, like a soap film with the same pressure on each side, the mean curvature is zero and, thus, is one where the two principal curvatures are equal and opposite at every point. For every closed circuit in the surface, the area is a minimum. Schwarz1 and Neovius2 showed that elements of such surfaces could be put together to give surfaces periodic in three dimensions. These periodic minimal surfaces are geometrical invariants, as are the regular polyhedra, but the former are curved. Minimal surfaces are appropriate for the description of various structures where internal surfaces are prominent and seek to adopt a minimum area or a zero mean curvature subject to their topology; thus they merit more complete numerical characterization. There seem to be at least 18 such surfaces3, with various symmetries and topologies, related to the crystallographic space groups. Recently, glyceryl mono-oleate (GMO) was shown by Longley and McIntosh4 to take the shape of the F-surface. The structure postulated is shown here to be in good agreement with an analysis of the fundamental geometry of periodic minimal surfaces.

  13. Laser Surface Treatment

    NASA Astrophysics Data System (ADS)

    Gnanamuthu, D. S.

    1980-10-01

    Experimental procedures and current state-of-the-art are presented for laser surface treating methods such as alloying, cladding, grain refining, and transformation hardening using a cw CO2 laser. Microstructural and x-ray analyses of the treated surfaces indicate that a laser beam can locally enhance surface properties. Laser alloying offers the possibility to selectively modify a low cost workpiece surface so that it has the desired high quality surface properties characteristic of high performance alloys. Laser cladding offers feasibility to apply high melting cladding alloys on low melting workpieces, to reduce the amount of dilution of cladding alloy with the workpieces, and the potential to apply dense ceramic claddings to metallic workpieces. Laser grain refining offers potential to either minimize or eliminate surface defects such as inclusions, intermetallic compounds, and pores, and to provide a refined grain structure. Laser transformation hardening provides the treated workpieces with a hard martensitic surface that has compressive stresses for enhanced fatigue life; in addition, reduction in wear rate of treated surfaces is achieved. This experimental study indicates that the use of lasers for surface treatment has several limitations. Further studies will provide better understanding for maximum utilization of laser surface treating processes.

  14. Positrons in surface physics

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, Christoph

    2016-12-01

    Within the last decade powerful methods have been developed to study surfaces using bright low-energy positron beams. These novel analysis tools exploit the unique properties of positron interaction with surfaces, which comprise the absence of exchange interaction, repulsive crystal potential and positron trapping in delocalized surface states at low energies. By applying reflection high-energy positron diffraction (RHEPD) one can benefit from the phenomenon of total reflection below a critical angle that is not present in electron surface diffraction. Therefore, RHEPD allows the determination of the atom positions of (reconstructed) surfaces with outstanding accuracy. The main advantages of positron annihilation induced Auger-electron spectroscopy (PAES) are the missing secondary electron background in the energy region of Auger-transitions and its topmost layer sensitivity for elemental analysis. In order to enable the investigation of the electron polarization at surfaces low-energy spin-polarized positrons are used to probe the outermost electrons of the surface. Furthermore, in fundamental research the preparation of well defined surfaces tailored for the production of bound leptonic systems plays an outstanding role. In this report, it is envisaged to cover both the fundamental aspects of positron surface interaction and the present status of surface studies using modern positron beam techniques.

  15. DNA ELECTROPHORESIS AT SURFACES

    SciTech Connect

    RAFAILOVICH, MIRIAM; SOKOLOV, JONATHAN; GERSAPPE, DILIP

    2003-09-01

    During this year we performed two major projects: I. We developed a detailed theoretical model which complements our experiments on surface DNA electrophoresis. We found that it was possible to enhance the separation of DNA chains by imposing a chemical nanoscale pattern on the surface. This approach utilized the surface interaction effect of the DNA chains with the substrate and is a refinement to our previous method in which DNA chains were separated on homogeneous flat surfaces. By introducing the nano-patterns on the surface, the conformational changes of DNA chains of different lengths can be amplified, which results in the different friction strengths with the substrate surface. Our results also show that, when compared to the DNA electrophoresis performed on homogeneous flat surfaces, nanopatterned surfaces offer a larger window in choosing different surface interactions to achieve separation. II. In collaboration with a large international manufacturer of skin care products we also embarked on a project involving photo toxicity of titanium dioxide nanoparticles, which are a key ingredient in sunscreen and cosmetic lotions. The results clearly implicated the nanoparticles in catalyzing damage to chromosomal DNA. We then used this knowledge to develop a polymer/anti-oxidant coating which prevented the photocatalytic reaction on DNA while still retaining the UV absorptive properties of the nanoparticles. The standard gel electrophoresis was not sufficient in determining the extent of the DNA damage. The conclusions of this study were based predominantly on analysis obtained with the surface electrophoresis method.

  16. On orbit surfacing of thermal control surfaces

    NASA Technical Reports Server (NTRS)

    Racette, G. W.

    1984-01-01

    Substrates to be contaminated and contamination source were prepared. Additional information on paint spray method apparatus was obtained. Silver teflon second surface mirror samples and S 13 GLO paint samples were mounted, photographed under the microscope and measured to establish baseline data. Atomic oxygen cleaning and spray painting are being considered. Electrostatic powder and plasma spray coating systems appear to have serious drawbacks.

  17. Bone Surface Mapping Method

    PubMed Central

    Fan, Yifang; Fan, Yubo; Li, Zhiyu; Lv, Changsheng; Zhang, Bo

    2012-01-01

    Bone shape is an important factor to determine the bone's structural function. For the asymmetrically shaped and anisotropically distributed bone in vivo, a surface mapping method is proposed on the bases of its geometric transformation invariance and its uniqueness of the principal axes of inertia. Using spiral CT scanning, we can make precise measurements to bone in vivo. The coordinate transformations lead to the principal axes of inertia, with which the prime meridian and the contour can be set. Methods such as tomographic reconstruction and boundary development are employed so that the surface of bone in vivo can be mapped. Experimental results show that the surface mapping method can reflect the shape features and help study the surface changes of bone in vivo. This method can be applied to research into the surface characteristics and changes of organ, tissue or cell whenever its digitalized surface is obtained. PMID:22412952

  18. Bone surface mapping method.

    PubMed

    Fan, Yifang; Fan, Yubo; Li, Zhiyu; Lv, Changsheng; Zhang, Bo

    2012-01-01

    Bone shape is an important factor to determine the bone's structural function. For the asymmetrically shaped and anisotropically distributed bone in vivo, a surface mapping method is proposed on the bases of its geometric transformation invariance and its uniqueness of the principal axes of inertia. Using spiral CT scanning, we can make precise measurements to bone in vivo. The coordinate transformations lead to the principal axes of inertia, with which the prime meridian and the contour can be set. Methods such as tomographic reconstruction and boundary development are employed so that the surface of bone in vivo can be mapped. Experimental results show that the surface mapping method can reflect the shape features and help study the surface changes of bone in vivo. This method can be applied to research into the surface characteristics and changes of organ, tissue or cell whenever its digitalized surface is obtained.

  19. Hydrodynamic Vortex on Surfaces

    NASA Astrophysics Data System (ADS)

    Ragazzo, Clodoaldo Grotta; de Barros Viglioni, Humberto Henrique

    2017-04-01

    The equations of motion for a system of point vortices on an oriented Riemannian surface of finite topological type are presented. The equations are obtained from a Green's function on the surface. The uniqueness of the Green's function is established under hydrodynamic conditions at the surface's boundaries and ends. The hydrodynamic force on a point vortex is computed using a new weak formulation of Euler's equation adapted to the point vortex context. An analogy between the hydrodynamic force on a massive point vortex and the electromagnetic force on a massive electric charge is presented as well as the equations of motion for massive vortices. Any noncompact Riemann surface admits a unique Riemannian metric such that a single vortex in the surface does not move ("Steady Vortex Metric"). Some examples of surfaces with steady vortex metric isometrically embedded in R^3 are presented.

  20. Surface texturing of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Mirtich, M. J.; Sovey, J. S. (Inventor)

    1982-01-01

    A method is disclosed for improving surface texture for adhesive bonding, metal bonding, substrate plating, decal substrate preparation, and biomedical implant applications. The surface to be bonded is dusted in a controlled fashion to produce a disbursed layer of fine mesh particles which serve as masks. The surface texture is produced by impinging gas ions on the masked surface. The textured surface takes the form of pillars or cones. The bonding material, such as a liquid epoxy, flows between the pillars which results in a bond having increased strength. For bonding metals a thin film of metal is vapor or sputter deposited onto the textured surface. Electroplating or electroless plating is then used to increase the metal thickness in the desired amount.

  1. Landsat surface reflectance data

    USGS Publications Warehouse

    ,

    2015-01-01

    Landsat satellite data have been produced, archived, and distributed by the U.S. Geological Survey since 1972. Users rely on these data for historical study of land surface change and require consistent radiometric data processed to the highest science standards. In support of the guidelines established through the Global Climate Observing System, the U.S. Geological Survey has embarked on production of higher-level Landsat data products to support land surface change studies. One such product is Landsat surface reflectance.

  2. Surface modification to waveguides

    DOEpatents

    Timberlake, J.R.; Ruzic, D.N.; Moore, R.L.; Cohen, S.A.; Manos, D.M.

    1982-06-16

    A method is described for treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1..mu.. to 5..mu.. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

  3. Impact of surface chemistry.

    PubMed

    Somorjai, Gabor A; Li, Yimin

    2011-01-18

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas-solid, liquid-solid, and solid-solid interfaces under reaction conditions are emphasized.

  4. Surface modification to waveguides

    DOEpatents

    Timberlake, John R.; Ruzic, David N.; Moore, Richard L.; Cohen, Samuel A.; Manos, Dennis M.

    1983-01-01

    A method of treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1.mu. to 5.mu. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

  5. Impact of surface chemistry

    PubMed Central

    Somorjai, Gabor A.; Li, Yimin

    2011-01-01

    The applications of molecular surface chemistry in heterogeneous catalyst technology, semiconductor-based technology, medical technology, anticorrosion and lubricant technology, and nanotechnology are highlighted in this perspective. The evolution of surface chemistry at the molecular level is reviewed, and the key roles of surface instrumentation developments for in situ studies of the gas–solid, liquid–solid, and solid–solid interfaces under reaction conditions are emphasized. PMID:20880833

  6. Diffusion on Cu surfaces

    NASA Technical Reports Server (NTRS)

    Karimi, Majid

    1993-01-01

    Understanding surface diffusion is essential in understanding surface phenomena, such as crystal growth, thin film growth, corrosion, physisorption, and chemisorption. Because of its importance, various experimental and theoretical efforts have been directed to understand this phenomena. The Field Ion Microscope (FIM) has been the major experimental tool for studying surface diffusion. FIM have been employed by various research groups to study surface diffusion of adatoms. Because of limitations of the FIM, such studies are only limited to a few surfaces: nickel, platinum, aluminum, iridium, tungsten, and rhodium. From the theoretical standpoint, various atomistic simulations are performed to study surface diffusion. In most of these calculations the Embedded Atom Method (EAM) along with the molecular static (MS) simulation are utilized. The EAM is a semi-empirical approach for modeling the interatomic interactions. The MS simulation is a technique for minimizing the total energy of a system of particles with respect to the positions of its particles. One of the objectives of this work is to develop the EAM functions for Cu and use them in conjunction with the molecular static (MS) simulation to study diffusion of a Cu atom on a perfect as well as stepped Cu(100) surfaces. This will provide a test of the validity of the EAM functions on Cu(100) surface and near the stepped environments. In particular, we construct a terrace-ledge-kink (TLK) model and calculate the migration energies of an atom on a terrace, near a ledge site, near a kink site, and going over a descending step. We have also calculated formation energies of an atom on the bare surface, a vacancy in the surface, a stepped surface, and a stepped-kink surface. Our results are compared with the available experimental and theoretical results.

  7. Surface nonlinear optics

    SciTech Connect

    Shen, Y.R.; Chen, C.K.; de Castro, A.R.B.

    1980-01-01

    Surface electromagnetic waves are waves propagating along the interface of two media. Their existence was predicted by Sommerfield in 1909. In recent years, interesting applications have been found in the study of overlayers and molecular adsorption on surfaces, in probing of phase transitions, and in measurements of refractive indices. In the laboratory, the nonlinear interaction of surface electromagnetic waves were studied. The preliminary results of this recent venture in this area are presented.

  8. Automated Surface Profilometer

    NASA Technical Reports Server (NTRS)

    Chern, E. James

    1993-01-01

    Computer-controlled system saves time and labor. Electromechanical scanning system automatically measures deviation of sheets and plates from flatness. Quickly measures surface profile and detects bumps, bulges, and indentations as small as 0.001 in. in height or depth. X-y table moves specimen to programmed locations under digital linear variable differential transformer (LVDT) while computer records surface-height readings of LVDT. Resulting graphical display shows surface contour.

  9. Electrochemistry of Metal Surfaces

    DTIC Science & Technology

    1990-06-30

    1-butene (BTE), 1-pentene (PTE), l-hexene (HXE), 1-- octene (OCE) and l--decene (DCE). Vibrational spectra of the adsorbed layers were obtained by use...Surface Sci., 92, 617 (1980). 39. Electrochemical Hydrogenation of Ethylene at Well-Defined Pt(100) and Pt(111) Surfaces. Arthur T. Hubbard, Mark A...Surf Sci., 147, 241 (1984). 75. A Comparison of Gas Phase and Electrochemical Hydrogenation of Ethylene at ** Platinum Surfaces. Andrzej Wieckowski

  10. Surface Tension Microscopy

    NASA Astrophysics Data System (ADS)

    Neumann, Burkhard; Engel, Horst; Schleifenbaum, Bernd

    1989-12-01

    A new microscopic technique will be presented for imaging surface topography and the locally varying surface tension of the object. With this technique it is possible to image the locally varying chemical composition of the specimen surface on a microscopic scale because the surface tension depends on the chemical composition. The imaging technique can be described as follows: By a simple preparation technique a thin (thickness several microns) liquid layer (e.g. immersion oil), is placed on the surface of the specimen. The resulting surface tension forces the boundary of the liquid layer to move. As the surface tension is a function of the location the boundary is modulated according to the magnitude of the surface tension at each place. Thus registering the shape of the moving boundary of the liquid layer at equidistant time intervals yields information on the specimen surface. The shape of the moving boundary is detected by a light microscope with differential interference contrast in combination with an image analysis system suited for real-time processing of image sequences in a threshold detection mode.

  11. Surface properties working group

    NASA Technical Reports Server (NTRS)

    Whitehead, A. B.; Cain, D. L.

    1973-01-01

    The objectives of the Mars surface properties working group are described. The objectives were: (1) determine a simple reference surface that would adequately represent the shape of the planet for cartographic purposes; (2) monitor the topographic results and to assess the relative calibration and accuracies of these techniques, thereby leading to a composite topographic map of the planet; and (3) facilitate the exchange of data in closely connected disciplines. The shape, topography, and isobaric surface are discussed along with the gravity field, and crustal density model. It was found that there is no simple reference figure for the planetary surface, although an offset, triaxial ellipsoid is adequate for most purposes.

  12. Peptide Amyloid Surface Display

    PubMed Central

    2015-01-01

    Homomeric self-assembly of peptides into amyloid fibers is a feature of many diseases. A central role has been suggested for the lateral fiber surface affecting gains of toxic function. To investigate this, a protein scaffold that presents a discrete, parallel β-sheet surface for amyloid subdomains up to eight residues in length has been designed. Scaffolds that present the fiber surface of islet amyloid polypeptide (IAPP) were prepared. The designs show sequence-specific surface effects apparent in that they gain the capacity to attenuate rates of IAPP self-assembly in solution and affect IAPP-induced toxicity in insulin-secreting cells. PMID:25541905

  13. Anodized dental implant surface.

    PubMed

    Mishra, Sunil Kumar; Kumar, Muktadar Anand; Chowdhary, Ramesh

    2017-01-01

    Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  14. Tribological properties of surfaces

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1978-01-01

    The real area of contact between two solid surfaces is only a small portion of the apparent area. Deformation of these areas can result in solid state contact through surface films. For clean solid to solid contact strong adhesive bonding occurs across the interface. Under these conditions many properties of the solid such as the metallurgical and chemical nature of metals can influence adhesion, friction, and wear behavior. The presence of gases, liquids, and solid films on the surface of solids alter markedly tribological characteristics. These surface films can also considerably change the mechanical effects of solid state contact on bulk material behavior.

  15. Surface nanobubbles and nanodroplets

    NASA Astrophysics Data System (ADS)

    Lohse, Detlef; Zhang, Xuehua

    2015-07-01

    Surface nanobubbles are nanoscopic gaseous domains on immersed substrates which can survive for days. They were first speculated to exist about 20 years ago, based on stepwise features in force curves between two hydrophobic surfaces, eventually leading to the first atomic force microscopy (AFM) image in 2000. While in the early years it was suspected that they may be an artifact caused by AFM, meanwhile their existence has been confirmed with various other methods, including through direct optical observation. Their existence seems to be paradoxical, as a simple classical estimate suggests that they should dissolve in microseconds, due to the large Laplace pressure inside these nanoscopic spherical-cap-shaped objects. Moreover, their contact angle (on the gas side) is much smaller than one would expect from macroscopic counterparts. This review will not only give an overview on surface nanobubbles, but also on surface nanodroplets, which are nanoscopic droplets (e.g., of oil) on (hydrophobic) substrates immersed in water, as they show similar properties and can easily be confused with surface nanobubbles and as they are produced in a similar way, namely, by a solvent exchange process, leading to local oversaturation of the water with gas or oil, respectively, and thus to nucleation. The review starts with how surface nanobubbles and nanodroplets can be made, how they can be observed (both individually and collectively), and what their properties are. Molecular dynamic simulations and theories to account for the long lifetime of the surface nanobubbles are then reported on. The crucial element contributing to the long lifetime of surface nanobubbles and nanodroplets is pinning of the three-phase contact line at chemical or geometric surface heterogeneities. The dynamical evolution of the surface nanobubbles then follows from the diffusion equation, Laplace's equation, and Henry's law. In particular, one obtains stable surface nanobubbles when the gas influx from

  16. Robust omniphobic surfaces

    PubMed Central

    Tuteja, Anish; Choi, Wonjae; Mabry, Joseph M.; McKinley, Gareth H.; Cohen, Robert E.

    2008-01-01

    Superhydrophobic surfaces display water contact angles greater than 150° in conjunction with low contact angle hysteresis. Microscopic pockets of air trapped beneath the water droplets placed on these surfaces lead to a composite solid-liquid-air interface in thermodynamic equilibrium. Previous experimental and theoretical studies suggest that it may not be possible to form similar fully-equilibrated, composite interfaces with drops of liquids, such as alkanes or alcohols, that possess significantly lower surface tension than water (γlv = 72.1 mN/m). In this work we develop surfaces possessing re-entrant texture that can support strongly metastable composite solid-liquid-air interfaces, even with very low surface tension liquids such as pentane (γlv = 15.7 mN/m). Furthermore, we propose four design parameters that predict the measured contact angles for a liquid droplet on a textured surface, as well as the robustness of the composite interface, based on the properties of the solid surface and the contacting liquid. These design parameters allow us to produce two different families of re-entrant surfaces— randomly-deposited electrospun fiber mats and precisely fabricated microhoodoo surfaces—that can each support a robust composite interface with essentially any liquid. These omniphobic surfaces display contact angles greater than 150° and low contact angle hysteresis with both polar and nonpolar liquids possessing a wide range of surface tensions. PMID:19001270

  17. Mars surface transportation options

    NASA Technical Reports Server (NTRS)

    Leitner, Jeffrey M.; Alred, John W.

    1986-01-01

    As the number of scientific experiments for the surface of Mars grows, the need for effective surface transportation becomes critical. Because of the diversity of the experiments proposed, as well as the desire to explore Mars from the equator to the poles, the optimum surface vehicle configuration is not obvious. Five candidate vehicles are described, with an estimate of their size and performance. In order to maximize the success of a manned Mars mission, it appears that two vehicles should be designed for surface transportation: an advanced long-range rover, and a remotely-piloted airplane.

  18. Surface breakdown of silicon

    NASA Astrophysics Data System (ADS)

    Feuerstein, R. J.; Senitzky, B.

    1991-07-01

    The surface electrical breakdown of n(+)nn(+) rectangular solid blocks of silicon was investigated. Studies were performed in air at pressures of 10 to the -6th torr and 1 atm, and in transformer oil, ethylene glycol, and deionized water, under pulsed electrical excitation. The breakdown voltage (BV) of these devices was found to increase as the dielectric constant of the ambient increased. Glow discharge cleaning of the surface in vacuum was found to have no effect on the BV. A theory of surface charging leading to field enhancement along the surface is developed on the basis of these findings.

  19. Martian surface simulations

    NASA Technical Reports Server (NTRS)

    Gaskell, R. W.

    1992-01-01

    Current scenarios for a Mars landing involve the extensive analysis of the surface near the landing site. Pinpoint landing, for example, requires a detailed mapping of the area from orbit for landmark identification and landing site selection, and the use by the lander of its own imaging data to recognize these landmarks and to guide itself safely to the surface. Hazard avoidance requires sufficient orbital imaging to ensure that safe landing sites exist, with the lander using its sensory data to find one of them. Once on the surface, a rover must be able to avoid or surmount obstacles, travel across surfaces with varying compositions and slopes, and navigate to a desired destination. Computer simulated Martian surfaces are being constructed to aid in the development of these exploration technologies. These surface simulations attempt to mimic the specific geologic episodes that built the surface, such as cratering, lava flows, and aeolian activity. Each episode takes a preexisting surface as a starting point, alters it in some way, and stores the new surface for further processing. This modular construction makes it possible for new processes to be included without altering existing software.

  20. THERMIONIC CONVERTER SURFACE CONDITIONS.

    DTIC Science & Technology

    THERMIONIC CONVERTERS , *THERMIONIC EMISSION, SURFACE PROPERTIES, MATERIALS, CESIUM, VAPORS, NIOBIUM COMPOUNDS, CARBIDES, MOLYBDENUM, TANTALUM, TUNGSTEN, NICKEL, RHENIUM, ELECTRODES, VOLTAGE, PERFORMANCE(ENGINEERING).

  1. Lunar Surface-to-Surface Power Transfer

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.

    2007-01-01

    A human lunar outpost, under NASA study for construction in the 2020's, has potential requirements to transfer electric power up to 50-kW across the lunar surface from 0.1 to 10-km distances. This power would be used to operate surface payloads located remotely from the outpost and/or outpost primary power grid. This paper describes concept designs for state-of-the-art technology power transfer subsystems including AC or DC power via cables, beamed radio frequency power and beamed laser power. Power transfer subsystem mass and performance are calculated and compared for each option. A simplified qualitative assessment of option operations, hazards, costs and technology needs is also described. Based on these concept designs and performance analyses, a DC power cabling subsystem is recommended to minimize subsystem mass and to minimize mission and programmatic costs and risks. Avenues for additional power transfer subsystem studies are recommended.

  2. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  3. Water surface is acidic

    PubMed Central

    Buch, Victoria; Milet, Anne; Vácha, Robert; Jungwirth, Pavel; Devlin, J. Paul

    2007-01-01

    Water autoionization reaction 2H2O → H3O− + OH− is a textbook process of basic importance, resulting in pH = 7 for pure water. However, pH of pure water surface is shown to be significantly lower, the reduction being caused by proton stabilization at the surface. The evidence presented here includes ab initio and classical molecular dynamics simulations of water slabs with solvated H3O+ and OH− ions, density functional studies of (H2O)48H+ clusters, and spectroscopic isotopic-exchange data for D2O substitutional impurities at the surface and in the interior of ice nanocrystals. Because H3O+ does, but OH− does not, display preference for surface sites, the H2O surface is predicted to be acidic with pH < 4.8. For similar reasons, the strength of some weak acids, such as carbonic acid, is expected to increase at the surface. Enhanced surface acidity can have a significant impact on aqueous surface chemistry, e.g., in the atmosphere. PMID:17452650

  4. Essentials of surface preparation

    SciTech Connect

    1995-12-31

    This book presents the latest and most effective surface preparation techniques through a compilation of 15 standards (including NACE/SSPC joint standards), articles, and reports. The book is conveniently sold in a looseleaf, tabbed binder so other material can be added. The four sections included cover Abrasive Blasting; Surface Contamination and Cleanliness; Profile, Finishing, Inspection, and Performance; and Concrete and Metallic Coatings.

  5. Chemical Reactions at Surfaces

    SciTech Connect

    Michael Henderson and Nancy Ryan Gray

    2010-04-14

    Chemical reactions at surfaces underlie some of the most important processes of today, including catalysis, energy conversion, microelectronics, human health and the environment. Understanding surface chemical reactions at a fundamental level is at the core of the field of surface science. The Gordon Research Conference on Chemical Reactions at Surfaces is one of the premiere meetings in the field. The program this year will cover a broad range of topics, including heterogeneous catalysis and surface chemistry, surfaces in environmental chemistry and energy conversion, reactions at the liquid-solid and liquid-gas interface, electronic materials growth and surface modification, biological interfaces, and electrons and photons at surfaces. An exciting program is planned, with contributions from outstanding speakers and discussion leaders from the international scientific community. The conference provides a dynamic environment with ample time for discussion and interaction. Attendees are encouraged to present posters; the poster sessions are historically well attended and stimulate additional discussions. The conference provides an excellent opportunity for junior researchers (e.g. graduate students or postdocs) to present their work and interact with established leaders in the field.

  6. Improving Surface Irrigation Performance

    USDA-ARS?s Scientific Manuscript database

    Surface irrigation systems often have a reputation for poor performance. One key feature of efficient surface irrigation systems is precision (e.g. laser-guided) land grading. Poor land grading can make other improvements ineffective. An important issue, related to land shaping, is developing the pr...

  7. Bacteria-surface interactions.

    PubMed

    Tuson, Hannah H; Weibel, Douglas B

    2013-05-14

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field.

  8. Protective Surfacing for Playgrounds.

    ERIC Educational Resources Information Center

    Frost, Joe L.

    Noting that 90 percent of serious playground injuries result from falls to hard surfaces, this paper reviews the advantages and disadvantages of various playground surfacing materials in terms of cost, climate, durability, aesthetics, and play value. Findings are based on the personal experience of the author, government documents, laboratory…

  9. Chapter 8:Surface Characterization

    Treesearch

    Mandla A. Tshabalala; Joseph Jakes; Mark R. VanLandingham; Shaoxia Wang; Jouko. Peltonen

    2013-01-01

    Surface properties of wood play an important role when wood is used or processed into different commodities such as siding, joinery, textiles, paper, sorption media, or wood composites. Thus, for example, the quality and durability of a wood coating are determined by the surface properties of the wood and the coating. The same is true for wood composites where the...

  10. Microbiological surface sampling cart

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.; Mills, S. M.

    1972-01-01

    Mobile sampling cart automatically swabs surfaces for the recovery of microorganisms. Unit operates without human involvement and provides for control of swabbing speed, rotation of cotton swab, and the pressure and angle applied to swab. Capability of reverse direction is also available. Sampling cart use is limited to flat surfaces.

  11. Discrete surface solitons.

    PubMed

    Makris, Konstantinos G; Suntsov, Sergiy; Christodoulides, Demetrios N; Stegeman, George I; Hache, Alain

    2005-09-15

    It is theoretically shown that discrete nonlinear surface waves are possible in waveguide lattices. These self-trapped states are located at the edge of the array and can exist only above a certain power threshold. The excitation characteristics and stability properties of these surface waves are systematically investigated.

  12. Bacteria-surface interactions

    PubMed Central

    Tuson, Hannah H.; Weibel, Douglas B.

    2013-01-01

    The interaction of bacteria with surfaces has important implications in a range of areas, including bioenergy, biofouling, biofilm formation, and the infection of plants and animals. Many of the interactions of bacteria with surfaces produce changes in the expression of genes that influence cell morphology and behavior, including genes essential for motility and surface attachment. Despite the attention that these phenotypes have garnered, the bacterial systems used for sensing and responding to surfaces are still not well understood. An understanding of these mechanisms will guide the development of new classes of materials that inhibit and promote cell growth, and complement studies of the physiology of bacteria in contact with surfaces. Recent studies from a range of fields in science and engineering are poised to guide future investigations in this area. This review summarizes recent studies on bacteria-surface interactions, discusses mechanisms of surface sensing and consequences of cell attachment, provides an overview of surfaces that have been used in bacterial studies, and highlights unanswered questions in this field. PMID:23930134

  13. Touching the Surface.

    ERIC Educational Resources Information Center

    Sussman, Beverly

    1992-01-01

    Author describes five self-developed activities that utilize readily available materials to help students understand surface tension in liquids. The hands-on activities allow students to see that strong bonds hold molecules together in a liquid and the molecules seem to stretch producing a "skin" at the surface of liquids. (PR)

  14. Superoleophobic Surface Formation on Fluoropolymer / Nanocomposite Surfaces

    DTIC Science & Technology

    2014-10-15

    Mabry J. M. “Superoleophobic surfaces through control of stochastic sprayed - on topography”, Langmuir, 28, 9834-9841 (2012). Campos, R.; Guenthner, A. J...DISTRIBUTION A: Approved for public release; distribution is unlimited. Spray Coating Process 4 • Silica Types • FF-Modified Hi-Sil233 • Unmodified Hi...CF-OCF3) and ethylene • Spray coating done via airbrush (Paasche, VLSTPRO) with a 1.06 mm diameter tip using compressed air (25 psi). The

  15. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  16. Surface and Near Surface Dynamics on Phobos

    NASA Astrophysics Data System (ADS)

    Hamelin, M.

    2008-12-01

    Phobos as a few small satellites in the solar system is orbiting around its primary inside the Roche limit. Therefore the surface material is loosely bounded and easily ejected by impactors. Whereas dynamics in the close vicinity of Phobos has been studied for both geophysical and navigation reasons, the dynamics on the surface itself has not been studied to the same extent. The gravitational field used here is the ellipsoidal model of Davis, 1981, that describes as well the past and future Phobos as it gets closer to Mars. We look at the trajectory of a test mass for any initial position and velocity. It can exhibit an unusual shape: for some initial positions a gliding test mass released with zero velocity can take off over some distance! Generally the trajectories are not 'down hill' as the motion is strongly dependent on the velocity. We discuss the consequences for material transport on or close to the surface, with in particular the possibility that some of the Phobos groves could have been dug out by rolling blocks.

  17. Workbench surface editor of brain cortical surface

    NASA Astrophysics Data System (ADS)

    Dow, Douglas E.; Nowinski, Wieslaw L.; Serra, Luis

    1996-04-01

    We have developed a 3D reach-in tool to manually reconstruct 3D cortical surface patches from 2D brain atlas images. The first application of our cortex editor is building 3D functional maps, specifically Brodmann's areas. This tool may also be useful in clinical practice to adjust incorrectly mapped atlas regions due to the deforming effect of lesions. The cortex editor allows a domain expert to control the correlation of control points across slices. Correct correlation has been difficult for 3D reconstruction algorithms because the atlas slices are far apart and because of the complex topology of the cortex which differs so much from slice to slice. Also, higher precision of the resulting surfaces is demanded since these define 3D brain atlas features upon which future stereotactic surgery may be based. The cortex editor described in this paper provides a tool suitable for a domain expert to use in defining the 3D surface of a Brodmann's area.

  18. Collapse of Surface Nanobubbles

    NASA Astrophysics Data System (ADS)

    Chan, Chon U.; Chen, Longquan; Arora, Manish; Ohl, Claus-Dieter

    2015-03-01

    Surface attached nanobubbles populate surfaces submerged in water. These nanobubbles have a much larger contact angle and longer lifetime than predicted by classical theory. Moreover, it is difficult to distinguish them from hydrophobic droplets, e.g., polymeric contamination, using standard atomic force microscopy. Here, we report fast dynamics of a three phase contact line moving over surface nanobubbles, polymeric droplets, and hydrophobic particles. The dynamics is distinct: across polymeric droplets the contact line quickly jumps and hydrophobic particles pin the contact line, while surface nanobubbles rapidly shrink once merging with the contact line, suggesting a method to differentiate nanoscopic gaseous, liquid, and solid structures. Although the collapse process of surface nanobubbles occurs within a few milliseconds, we show that it is dominated by microscopic dynamics rather than bulk hydrodynamics.

  19. Fractal surface finish

    SciTech Connect

    Church, E.L.

    1988-04-15

    Surface finish measurements are usually fitted to models of the finish correlation function which are parametrized in terms of root-mean-square roughnesses, sigma, and correlation lengths, l. Highly finished optical surfaces, however, are frequently better described by fractal models, which involve inverse power-law spectra and are parametrized by spectral strengths, K/sub n/, and spectral indices, n. Analyzing measurements of fractal surfaces in terms of sigma and l gives results which are not intrinsic surface parameters but which depend on the bandwidth parameters of the measurement process used. This paper derives expressions for these pseudoparameters and discusses the errors involved in using them for the characterization and specification of surface finish.

  20. Fractal surface finish

    SciTech Connect

    Church, E.L.

    1988-01-01

    Surface finish measurements are usually fitted to models of the finish correlation function which are parameterized in terms of root-mean-square roughness, sigma, and correlation lengths, l. Highly-finished optical surfaces, however, are frequently better described by fractal models, which involve inverse-power-law spectra and are parameterized by spectral strengths, K/sub n/, and spectral indices, n. Analyzing measurements of fractal surfaces in terms of sigma and l gives results which are not intrinsic surface parameters but which depend on the bandwidth parameters of the measurement process used. This paper derives expressions for these pseudo parameters and discusses the errors involved in using them for the characterization and specification of surface finish. 30 refs., 5 figs., 1 tab.

  1. Electrohydrodynamics near hydrophobic surfaces.

    PubMed

    Maduar, S R; Belyaev, A V; Lobaskin, V; Vinogradova, O I

    2015-03-20

    We show that an electro-osmotic flow near the slippery hydrophobic surface depends strongly on the mobility of surface charges, which are balanced by counterions of the electrostatic diffuse layer. For a hydrophobic surface with immobile charges, the fluid transport is considerably amplified by the existence of a hydrodynamic slippage. In contrast, near the hydrophobic surface with mobile adsorbed charges, it is also controlled by an additional electric force, which increases the shear stress at the slipping interface. To account for this, we formulate electrohydrodynamic boundary conditions at the slipping interface, which should be applied to quantify electro-osmotic flows instead of hydrodynamic boundary conditions. Our theoretical predictions are fully supported by dissipative particle dynamics simulations with explicit charges. These results lead to a new interpretation of zeta potential of hydrophobic surfaces.

  2. Surface functionalisation of polymers.

    PubMed

    Hetemi, Dardan; Pinson, Jean

    2017-10-02

    Many applications of polymers require the functionalisation of their surface for use in sensors, composite materials, membranes, microfluidic and biomedical devices and many others. Such surface modifications endow the surface with new properties independent of those of the bulk polymer. This tutorial review describes the different methods, based on very diverse principles, that are available to perform this surface functionalisation, including plasma and UV irradiation, atomic layer deposition, electrochemistry, oxidation, reduction, hydrolysis, the use of radicals and grafting "on" or "from" polymers. The principles of the different methods are briefly described and many examples are given to highlight the possibilities of the methods and the possible applications. A section is devoted to the surface modification of polymeric nanoparticles.

  3. Magnesium: Engineering the Surface

    NASA Astrophysics Data System (ADS)

    Chen, X. B.; Yang, H. Y.; Abbott, T. B.; Easton, M. A.; Birbilis, N.

    2012-06-01

    Magnesium (Mg) and its alloys provide numerous benefits as lightweight materials; however, industrial deployment of Mg in most instances requires anticorrosion coatings. Engineering the Mg surface is an area that has been undergoing intense research recently. Surface engineering commences with the "pretreatment" step, which can be used to modify the surface composition and morphology, resulting in surface enrichment or depletion of alloying elements. Following this, electrochemical plating (including electro- and electroless plating) and conversion coatings have emerged as common means of coating Mg. In this study, we present the key aspects relating to the science and technology associated with pretreatment, electrochemical plating, and conversion coatings. This is followed by experimental examples of engineered surfaces of industrial relevance.

  4. Surface Habitat Systems

    NASA Technical Reports Server (NTRS)

    Kennedy, Kriss J.

    2009-01-01

    The Surface Habitat Systems (SHS) Focused Investment Group (FIG) is part of the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) effort to provide a focused direction and funding to the various projects that are working on human surface habitat designs and technologies for the planetary exploration missions. The overall SHS-FIG effort focuses on directing and guiding those projects that: 1) develop and demonstrate new surface habitat system concepts, innovations, and technologies to support human exploration missions, 2) improve environmental systems that interact with human habitats, 3) handle and emplace human surface habitats, and 4) focus on supporting humans living and working in habitats on planetary surfaces. The activity areas of the SHS FIG described herein are focused on the surface habitat project near-term objectives as described in this document. The SHS-FIG effort focuses on mitigating surface habitat risks (as identified by the Lunar Surface Systems Project Office (LSSPO) Surface Habitat Element Team; and concentrates on developing surface habitat technologies as identified in the FY08 gap analysis. The surface habitat gap assessment will be updated annually as the surface architecture and surface habitat definition continues to mature. These technologies are mapped to the SHS-FIG Strategic Development Roadmap. The Roadmap will bring to light the areas where additional innovative efforts are needed to support the development of habitat concepts and designs and the development of new technologies to support of the LSSPO Habitation Element development plan. Three specific areas of development that address Lunar Architecture Team (LAT)-2 and Constellation Architecture Team (CxAT) Lunar habitat design issues or risks will be focused on by the SHS-FIG. The SHS-FIG will establish four areas of development that will help the projects prepare in their planning for surface habitat systems development. Those development areas are

  5. Dynamics at Surfaces

    SciTech Connect

    Sylvia Ceyer, Nancy Ryan Gray

    2010-05-04

    The 2009 Gordon Conference on Dynamics at Surfaces is the 30th anniversary of a meeting held every two years that is attended by leading researchers in the area of experimental and theoretical dynamics at liquid and solid surfaces. The conference focuses on the dynamics of the interaction of molecules with either liquid or solid surfaces, the dynamics of the outermost layer of liquid and solid surfaces and the dynamics at the liquid-solid interface. Specific topics that are featured include state-to-state dynamics, non-adiabatic interactions in molecule-metal systems, photon induced desorption from semiconductor and metal surfaces, ultrafast x-ray and electron diffraction as probes of the dynamics of ablation, ultrafast vibrational spectroscopy of water surface dynamics, dynamics of a single adsorbate, growth at nano-scale mineral surfaces, dynamics of atom recombination on interstellar dust grains and the dynamics of the interaction of water with lipid bilayers. The conference brings together investigators from a variety of scientific disciplines including chemistry, physics, materials science, geology and biophysics.

  6. Resistance electroslag (RES) surfacing

    SciTech Connect

    Forsberg, S.G.

    1985-08-01

    RES-surfacing is an abbreviation of resistance electroslag surfacing. The ElectroSlag Welding (ESW) process is wellknown for the welding of heavy-walled materials. During the past few years, a RES-surfacing system has been developed, in which a strip electrode is used in an ESW process. This is a development of the submerged arc welding (SAW) surfacing process using strip electrodes, which has been used in industry for many years. The basic difference between the SAW- and RES-surfacing processes is in the way of obtaining penetration in the base metal, and in fusion of the strip electrode and flux. In the SAW process, the required heat is derived from an electric arc; in the RES-process, it is obtained by resistance heating (i.e., the Joule effect) as a result of current flowing through a shallow molten pool of electrically conductive slag. To satisfy the basic differences in the processes, specific combinations of strip electrodes and fluxes have been developed. The welding equipment used for RES-surfacing is basically the same as for SAW-surfacing, except for minor modifications of the welding head due to heat radiation from the visible molten slag pool, and the use of additional equipment for magnetic control of the molten pool. result of the magnetic control of the molten pool.

  7. Precision surface measurement.

    PubMed

    Jiang, X

    2012-08-28

    Surface size, geometry and texture are some of the most influential subjects in the fields of precision and ultra-precision engineering, defining the functional interface through which emerging products operate. Next-generation products demand super-smooth surfaces, freeform geometries or even deterministically introduced microstructures to provide functional performance. Technological progress using these surfaces types is possible only if the associated manufacturing processes are rigorously controlled and the surfaces are measurable. Metrology for advanced surfaces is not established. The current state of the art is challenged in respect to (i) surface characteristics, extremity of size, ultra precision, quality, geometric complexity, or combinations of these aspects, and (ii) measurement technology for the manufacturing environment, in particular, online, non-contact, high speed, ease of use, small footprint and robustness. This study addresses the challenges in this subject area and discusses some fundaments and principles derived from interdisciplinary research. The combination of these aspects is enabling the creation of manufacturing-environment-based measurement technology. This is expected to facilitate advanced surface manufacture over a wide range of sectors, including large science programmes and high-technology engineering.

  8. Progressive Response Surfaces

    NASA Technical Reports Server (NTRS)

    Romero, V. J.; Swiler, L. P.

    2004-01-01

    Response surface functions are often used as simple and inexpensive replacements for computationally expensive computer models that simulate the behavior of a complex system over some parameter space. Progressive response surfaces are ones that are built up progressively as global information is added from new sample points in the parameter space. As the response surfaces are globally upgraded based on new information, heuristic indications of the convergence of the response surface approximation to the exact (fitted) function can be inferred. Sampling points can be incrementally added in a structured fashion, or in an unstructured fashion. Whatever the approach, at least in early stages of sampling it is usually desirable to sample the entire parameter space uniformly. At later stages of sampling, depending on the nature of the quantity being resolved, it may be desirable to continue sampling uniformly over the entire parameter space (Progressive response surfaces), or to switch to a focusing/economizing strategy of preferentially sampling certain regions of the parameter space based on information gained in early stages of sampling (Adaptive response surfaces). Here we consider Progressive response surfaces where a balanced indication of global response over the parameter space is desired.We use a variant of Moving Least Squares to fit and interpolate structured and unstructured point sets over the parameter space. On a 2-D test problem we compare response surface accuracy for three incremental sampling methods: Progressive Lattice Sampling; Simple-Random Monte Carlo; and Halton Quasi-Monte-Carlo sequences. We are ultimately after a system for constructing efficiently upgradable response surface approximations with reliable error estimates.

  9. Vacuum probe surface sampler

    NASA Technical Reports Server (NTRS)

    Zahlava, B. A. (Inventor)

    1973-01-01

    A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

  10. Vortex pairs on surfaces

    SciTech Connect

    Koiller, Jair

    2009-05-06

    A pair of infinitesimally close opposite vortices moving on a curved surface moves along a geodesic, according to a conjecture by Kimura. We outline a proof. Numerical simulations are presented for a pair of opposite vortices at a close but nonzero distance on a surface of revolution, the catenoid. We conjecture that the vortex pair system on a triaxial ellipsoid is a KAM perturbation of Jacobi's geodesic problem. We outline some preliminary calculations required for this study. Finding the surfaces for which the vortex pair system is integrable is in order.

  11. Spectra of Surface Waves

    DTIC Science & Technology

    1989-03-22

    with a wave follower during Marsen. J. Gophysical Res. 88, 9844-9849. 11. Hughes, B.A., 1978. The effects on internal waves on surface waves : 2...Spectra of Surface Waves K. Watson March 1989 JSR-88-130 Approved for public release; distribution unlimited. DTIC SELECTE JUN0 11989 0 JASONE The...Arlington, VA 22209 8503Z 11. TITLE (hlde Secvfty Cof.kaftn) SPECTRA OF SURFACE WAVES (U) 12. PERSONAL AUTHOfRS) K. Watson 13a. TYPE OF REPORT 13b. TIME

  12. Planetary surface weathering

    NASA Technical Reports Server (NTRS)

    Gooding, J. L.

    1986-01-01

    The weathering of planetary surfaces is treated. Both physical and chemical weathering (reactions between minerals or mineraloids and planetary volatiles through oxidation, hydration, carbonation, or solution processes) are discussed. Venus, earth, and Mars all possess permanent atmospheres such that weathering should be expected to significantly affect their respective surfaces. In contrast, Mercury and the moon lack permanent atmospheres but conceivably could experience surface weathering in response to transient atmospheres generated by volcanic or impact cratering events. Weathering processes can be postulated for other rocky objects including Io, Titan, asteroids, and comets.

  13. Stability of capillary surfaces

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark

    1991-01-01

    An extensive data set quantifying the stability limits of capillary surfaces for a wide range of fluid properties, container geometry, and input disturbance and orientation does not currently exist. To begin to provide such a data set an experimental apparatus has been designed for which the dynamics and stability of fluid interfaces will be investigated. The apparatus consists primarily of a programmable shaker table and a high speed motion picture and video camera for viewing the fluid surface as drop tower tests will be performed to note the stability of a variety of surface/vessel configurations.

  14. Surface Phonons and Polaritons.

    DTIC Science & Technology

    1976-01-01

    for an impurity in the surface of a crystal could be observed in the one phonon cross section for the resonant absorption or e.ission of ,—rays by...localized at the surface. The w5 — dependence has a simple physical origin. It is well known that the cross section for scattering of bulk phonons by a...propagate. In Section II of the present Chapter we present the theory underlying the surface induced vibrational properties of crystals which we have

  15. Surface science with aerosols

    NASA Astrophysics Data System (ADS)

    Bluhm, H.; Siegmann, H. C.

    2009-06-01

    Experimental surface science with aerosol particles under atmospheric conditions is becoming a realistic possibility. The first part of this critical review focuses on nano-scopic aerosols generated in combustion of organic fuels at ambient pressures. The bizarre shape of soot agglomerates resists a simple definition of size and surface area. Yet a measure of the size known as the mobility diameter can be extracted from the mobility of the particles in their carrier gas. The total surface area must be divided into an active and a passive part. At the active surface, mass, energy, and momentum is exchanged with the molecules of the carrier gas. The active surface thus determines the dynamical properties of the particles. The passive surface is the surface enclosed in the interior as well as the surface in bays or cracks or, with larger particles, in the dead point of the laminar flow; it determines particle properties on a longer time scale. Simple automatic portable sensors measure the number density of airborne particles, their "size" and a characteristic fingerprint of the surface chemistry, making it possible to determine the source from which the particle was emitted. The response time of the sensors is ˜1 s, hence one can monitor dynamical changes of the particles such as adsorption of water in the atmosphere. In the second part we examine a number of surface science techniques that have been used to characterize surfaces important to atmospheric chemistry in more detail, in particular the uptake of water and the influence of surfactants. We illustrate the application of these techniques to the investigation of alkali halide surfaces as a function of relative humidity. Finally we give first examples on how infrared spectroscopy and synchrotron-based ambient pressure X-ray photoelectron spectroscopy have been used to study more realistic aerosol particles, under conditions of ambient humidity. These examples show that in situ chemical analysis of the particles

  16. Surface layers of bacteria.

    PubMed Central

    Beveridge, T J; Graham, L L

    1991-01-01

    Since bacteria are so small, microscopy has traditionally been used to study them as individual cells. To this end, electron microscopy has been a most powerful tool for studying bacterial surfaces; the viewing of macromolecular arrangements of some surfaces is now possible. This review compares older conventional electron-microscopic methods with new cryotechniques currently available and the results each has produced. Emphasis is not placed on the methodology but, rather, on the importance of the results in terms of our perception of the makeup and function of bacterial surfaces and their interaction with the surrounding environment. Images PMID:1723487

  17. Scattering of Light and Surface Plasmon Polaritons from Rough Surfaces

    DTIC Science & Technology

    2013-06-14

    AFRL-RV-PS- AFRL-RV-PS- TR-2013-0049 TR-2013-0049 SCATTERING OF LIGHT AND SURFACE PLASMON POLARITONS FROM ROUGH SURFACES Alexei A...2013 4. TITLE AND SUBTITLE Scattering of Light and Surface Plasmon Polaritons from Rough Surfaces 5a. CONTRACT NUMBER FA9453-08-C-0230 5b...of several properties of surface plasmon polaritons on structured surfaces are described, together with results for the scattering of surface plasmon

  18. Comet Surface Sampling Technologies

    NASA Astrophysics Data System (ADS)

    Zacny, K.; Chu, P.; Paulsen, G.; Indyk, S.

    2014-06-01

    The goal of the Comet Surface Sample Return (CSSR) is to acquire and return to Earth a ≥500 cc) sample. Honeybee developed several sampling technologies including a standalone CSSR Probe (CSSRP) and Pyramid Comet Sampler (PyCoS).

  19. Surface Protonics Promotes Catalysis

    NASA Astrophysics Data System (ADS)

    Manabe, R.; Okada, S.; Inagaki, R.; Oshima, K.; Ogo, S.; Sekine, Y.

    2016-12-01

    Catalytic steam reforming of methane for hydrogen production proceeds even at 473 K over 1 wt% Pd/CeO2 catalyst in an electric field, thanks to the surface protonics. Kinetic analyses demonstrated the synergetic effect between catalytic reaction and electric field, revealing strengthened water pressure dependence of the reaction rate when applying an electric field, with one-third the apparent activation energy at the lower reaction temperature range. Operando–IR measurements revealed that proton conduction via adsorbed water on the catalyst surface occurred during electric field application. Methane was activated by proton collision at the Pd–CeO2 interface, based on the inverse kinetic isotope effect. Proton conduction on the catalyst surface plays an important role in methane activation at low temperature. This report is the first describing promotion of the catalytic reaction by surface protonics.

  20. Analyzing earth's surface data

    NASA Technical Reports Server (NTRS)

    Barr, D. J.; Elifrits, C. D.

    1979-01-01

    Manual discusses simple inexpensive image analysis technique used to interpret photographs and scanner of data of Earth's surface. Manual is designed for those who have no need for sophisticated computer-automated analysis procedures.

  1. Focus: Surface Characterization.

    ERIC Educational Resources Information Center

    Winograd, Nicholas

    1985-01-01

    The 38th Annual Summer Symposium on Analytical Chemistry (June 18-20, 1985) focused on the surface characterization of catalytic and electronic materials. Highlights of the symposium are provided, including presentations that considered lasers and microscopy. (JN)

  2. Mars Surface Mission Workshop

    NASA Technical Reports Server (NTRS)

    Duke, M. B. (Editor)

    1997-01-01

    A workshop was held at the Lunar and Planetary Institute on September 4-5, 1997, to address the surface elements of the Mars Reference Mission now being reviewed by NASA. The workshop considered the current reference mission and addressed the types of activities that would be expected for science and resource exploration and facilities operations. A set of activities was defined that can be used to construct "vignettes" of the surface mission. These vignettes can form the basis for describing the importance of the surface mission, for illustrating aspects of the surface mission, and for allowing others to extend and revise these initial ideas. The topic is rich with opportunities for additional conceptualization. It is recommended that NASA consider supporting university design teams to conduct further analysis of the possibilities.

  3. Map of Pluto Surface

    NASA Image and Video Library

    1998-03-28

    This image-based surface map of Pluto was assembled by computer image processing software from four separate images of Pluto disk taken with the European Space Agency Faint Object Camera aboard NASA Hubble Space Telescope.

  4. Sea Surface Salinity

    NASA Image and Video Library

    The heat of the sun also forces evaporation at the ocean's surface, which puts water vapor into the atmosphere but leaves minerals and salts behind, keeping the ocean salty. The salinity of the oce...

  5. Morpheus Surface Approach

    NASA Image and Video Library

    This animation shows the Project Morpheus lander flying a kilometer-long simulated surface approach while avoiding hazards in a landing field. The approach takes place at the Shuttle Landing Facili...

  6. Microswimmers near surfaces

    NASA Astrophysics Data System (ADS)

    Elgeti, Jens; Gompper, Gerhard

    2016-11-01

    Both, in their natural environment and in a controlled experimental setup, microswimmers regularly interact with surfaces. These surfaces provide a steric boundary, both for the swimming motion and the hydrodynamic flow pattern. These effects typically imply a strong accumulation of microswimmers near surfaces. While some generic features can be derived, details of the swimmer shape and propulsion mechanism matter, which give rise to a broad range of adhesion phenomena and have to be taken into account to predict the surface accumulation for a given swimmer. We show in this minireview how numerical simulations and analytic theory can be used to predict the accumulation statistics for different systems, with an emphasis on swimmer shape, hydrodynamics interactions, and type of noisy dynamics.

  7. Surface superconductivity in lead

    SciTech Connect

    Khlyustikov, I. N.

    2016-02-15

    A transition to the surface superconducting state is detected in lead single crystals at a temperature approximately 0.25 mK higher than the bulk superconducting transition temperature. The (H, T) phase diagram of this state is analyzed.

  8. Surface Tension of Spacetime

    NASA Astrophysics Data System (ADS)

    Perko, Howard

    2017-01-01

    Concepts from physical chemistry and more specifically surface tension are introduced to spacetime. Lagrangian equations of motion for membranes of curved spacetime manifold are derived. The equations of motion in spatial directions are dispersion equations and can be rearranged to Schrodinger's equation where Plank's constant is related to membrane elastic modulus. The equation of motion in the time-direction has two immediately recognizable solutions: electromagnetic waves and corpuscles. The corpuscular membrane solution can assume different genus depending on quantized amounts of surface energy. A metric tensor that relates empty flat spacetime to energetic curved spacetime is found that satisfies general relativity. Application of the surface tension to quantum electrodynamics and implications for quantum chromodynamics are discussed. Although much work remains, it is suggested that spacetime surface tension may provide a classical explanation that combines general relativity with field theories in quantum mechanics and atomic particle physics.

  9. Flexible Polyhedral Surfaces.

    ERIC Educational Resources Information Center

    Alexandrov, V. A.

    1998-01-01

    Discusses some questions connected with Cauchy's theorem which states that two convex closed polyhedral surfaces whose corresponding faces are congruent and whose faces adjoin each other in the same way are congruent. Describes how to construct a flexible polyhedron. (ASK)

  10. Surface chemistry: Mussel power

    NASA Astrophysics Data System (ADS)

    Waite, J. Herbert

    2008-01-01

    The adhesive proteins secreted by mussels are the inspiration behind a versatile approach to the surface modification of a wide range of inorganic and organic materials, resulting in the fabrication of multifunctional coatings for a variety of applications.

  11. Surface composition of Hyperion.

    PubMed

    Cruikshank, D P; Dalton, J B; Dalle Ore, C M; Bauer, J; Stephan, K; Filacchione, G; Hendrix, A R; Hansen, C J; Coradini, A; Cerroni, P; Tosi, F; Capaccioni, F; Jaumann, R; Buratti, B J; Clark, R N; Brown, R H; Nelson, R M; McCord, T B; Baines, K H; Nicholson, P D; Sotin, C; Meyer, A W; Bellucci, G; Combes, M; Bibring, J-P; Langevin, Y; Sicardy, B; Matson, D L; Formisano, V; Drossart, P; Mennella, V

    2007-07-05

    Hyperion, Saturn's eighth largest icy satellite, is a body of irregular shape in a state of chaotic rotation. The surface is segregated into two distinct units. A spatially dominant high-albedo unit having the strong signature of H2O ice contrasts with a unit that is about a factor of four lower in albedo and is found mostly in the bottoms of cup-like craters. Here we report observations of Hyperion's surface in the ultraviolet and near-infrared spectral regions with two optical remote sensing instruments on the Cassini spacecraft at closest approach during a fly-by on 25-26 September 2005. The close fly-by afforded us the opportunity to obtain separate reflectance spectra of the high- and low-albedo surface components. The low-albedo material has spectral similarities and compositional signatures that link it with the surface of Phoebe and a hemisphere-wide superficial coating on Iapetus.

  12. Triangulation of NURBS Surfaces

    NASA Technical Reports Server (NTRS)

    Samareh-Abolhassani, Jamshid

    1994-01-01

    A technique is presented for triangulation of NURBS surfaces. This technique is built upon an advancing front technique combined with grid point projection. This combined approach has been successfully implemented for structured and unstructured grids.

  13. Surface Protonics Promotes Catalysis

    PubMed Central

    Manabe, R.; Okada, S.; Inagaki, R.; Oshima, K.; Ogo, S.; Sekine, Y.

    2016-01-01

    Catalytic steam reforming of methane for hydrogen production proceeds even at 473 K over 1 wt% Pd/CeO2 catalyst in an electric field, thanks to the surface protonics. Kinetic analyses demonstrated the synergetic effect between catalytic reaction and electric field, revealing strengthened water pressure dependence of the reaction rate when applying an electric field, with one-third the apparent activation energy at the lower reaction temperature range. Operando–IR measurements revealed that proton conduction via adsorbed water on the catalyst surface occurred during electric field application. Methane was activated by proton collision at the Pd–CeO2 interface, based on the inverse kinetic isotope effect. Proton conduction on the catalyst surface plays an important role in methane activation at low temperature. This report is the first describing promotion of the catalytic reaction by surface protonics. PMID:27905505

  14. Surface Plasmon Based Spectrometer

    NASA Astrophysics Data System (ADS)

    Wig, Andrew; Passian, Ali; Boudreaux, Philip; Ferrell, Tom

    2008-03-01

    A spectrometer that uses surface plasmon excitation in thin metal films to separate light into its component wavelengths is described. The use of surface plasmons as a dispersive medium sets this spectrometer apart from prism, grating, and interference based variants and allows for the miniaturization of this device. Theoretical and experimental results are presented for two different operation models. In the first case surface plasmon tunneling in the near field is used to provide transmission spectra of different broad band-pass, glass filters across the visible wavelength range with high stray-light rejection at low resolution as well as absorption spectra of chlorophyll extracted from a spinach leaf. The second model looks at the far field components of surface plasmon scattering.

  15. Surface and submicron physics

    SciTech Connect

    Wright, H. A.

    1982-01-01

    The following research projects are briefly described: resonance ionization mass spectroscopy, an extreme uv transmission grating monochrometers, electon attenuation lengths in solids, surface enhanced Raman spectroscopy, and easy events in irradiated liquid water. (WHK)

  16. Topography of Vesta Surface

    NASA Image and Video Library

    2011-08-26

    This view of the topography of asteroid Vesta surface is composed of several images obtained with the framing camera on NASA Dawn spacecraft on August 6, 2011. The image mosaic is shown superimposed on a digital terrain model.

  17. Designing biomimetic antifouling surfaces.

    PubMed

    Salta, Maria; Wharton, Julian A; Stoodley, Paul; Dennington, Simon P; Goodes, Liam R; Werwinski, Stéphane; Mart, Ugar; Wood, Robert J K; Stokes, Keith R

    2010-10-28

    Marine biofouling is the accumulation of biological material on underwater surfaces, which has plagued both commercial and naval fleets. Biomimetic approaches may well provide new insights into designing and developing alternative, non-toxic, surface-active antifouling (AF) technologies. In the marine environment, all submerged surfaces are affected by the attachment of fouling organisms, such as bacteria, diatoms, algae and invertebrates, causing increased hydrodynamic drag, resulting in increased fuel consumption, and decreased speed and operational range. There are also additional expenses of dry-docking, together with increased fuel costs and corrosion, which are all important economic factors that demand the prevention of biofouling. Past solutions to AF have generally used toxic paints or coatings that have had a detrimental effect on marine life worldwide. The prohibited use of these antifoulants has led to the search for biologically inspired AF strategies. This review will explore the natural and biomimetic AF surface strategies for marine systems.

  18. Biological surface science

    NASA Astrophysics Data System (ADS)

    Kasemo, Bengt

    2002-03-01

    Biological surface science (BioSS), as defined here is the broad interdisciplinary area where properties and processes at interfaces between synthetic materials and biological environments are investigated and biofunctional surfaces are fabricated. Six examples are used to introduce and discuss the subject: Medical implants in the human body, biosensors and biochips for diagnostics, tissue engineering, bioelectronics, artificial photosynthesis, and biomimetic materials. They are areas of varying maturity, together constituting a strong driving force for the current rapid development of BioSS. The second driving force is the purely scientific challenges and opportunities to explore the mutual interaction between biological components and surfaces. Model systems range from the unique water structures at solid surfaces and water shells around proteins and biomembranes, via amino and nucleic acids, proteins, DNA, phospholipid membranes, to cells and living tissue at surfaces. At one end of the spectrum the scientific challenge is to map out the structures, bonding, dynamics and kinetics of biomolecules at surfaces in a similar way as has been done for simple molecules during the past three decades in surface science. At the other end of the complexity spectrum one addresses how biofunctional surfaces participate in and can be designed to constructively participate in the total communication system of cells and tissue. Biofunctional surfaces call for advanced design and preparation in order to match the sophisticated (bio) recognition ability of biological systems. Specifically this requires combined topographic, chemical and visco-elastic patterns on surfaces to match proteins at the nm scale and cells at the micrometer scale. Essentially all methods of surface science are useful. High-resolution (e.g. scanning probe) microscopies, spatially resolved and high sensitivity, non-invasive optical spectroscopies, self-organizing monolayers, and nano- and microfabrication

  19. Surface Production of Ions

    DTIC Science & Technology

    1992-05-26

    restrictions present in most surface baffle . The base pressure was 3 .. 10 ’ Torr. The experimen- conversion sources operating at 1(X) eV bombarding...are described. These guns use a novel source of cesium ions that combine the advantages of porous metal ionizers with those of aluminosilicate...emitters. Ccx um ions are chemically stored in a solid electrolyte pellet and are thermionically emitted from a porous thin film of tungsten at the surface

  20. Triangulating Trimmed NURBS Surfaces

    DTIC Science & Technology

    2000-01-01

    Curve and Surface Design: Saint-Malo 1999 381 Pierre-Jean Laurent, Paul Sablonnibre, and Larry L. Schumaker ( eds .), pp. 381-388. Copyright 0 2000 by...the boundary of its neighboring surface. References 1. Baehmann, P. L., S. L. Wittchen , M. S. Shephard, K. R. Grice and M. A. Yerry, Robust...and D. Eppstein, Mesh generation and optimal triangulation, in Computing in Euclidean Geometry, 2nd ed ., D.-Z. Du and F. K. Hwang, ( eds .), World

  1. Surface Temperatures of Exoplanets

    NASA Astrophysics Data System (ADS)

    Weisfeiler, M.; Turcotte, D. L.; Kellogg, L. H.

    2015-12-01

    In the search for habitable exoplanets, the planet's surface temperature plays a crucial role. Unfortunately, direct measurements of surface temperature are not available at this time. Many physical processes influence the surface temperature distribution of a planet. However, the dominating influence is an energy balance between the stellar radiation input and the radiative surface loss of heat. With the further assumptions of a uniform planetary surface temperature, no filtering of the incoming radiation, and black body emission, the only variables are the stellar luminosity and the radial distance of the exoplanet from the star. For the solar system, agreement with observations is quite good except for Venus. The agreement is good for both the inner planets and the outer planets. In this paper we systematically look at methods of improving the zero order approach given above. We consider the filtering of the incoming radiation and the grey body emission. This accounts for the greenhouse effect and can explain the surface temperature of Venus. We systematically vary the filtering of incoming radiation and the emissivities of the daytime and nighttime surfaces. There is evidence that greenhouse heating on the Earth is primarily at nighttime. Different emissivities can explain this effect. It is straightforward to extend the energy balance analysis to include the latitude dependence of surface temperature. Good agreement is obtained at low latitudes but temperature buffering and heat transport by the oceans and atmosphere are clearly important at high latitudes. It is also straightforward to estimate the difference between the daytime and nighttime temperatures. The important parameter is the rotation rate of the exoplanet. The roles of the oceans and the atmosphere in moderating this difference on the Earth will be discussed. Some exoplanets are sufficiently close to their star to have temperatures above the melting temperatures and even the vaporization

  2. Multifunctional thin film surface

    DOEpatents

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  3. Lights illuminate surfaces superluminally

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.; Zhong, Qi; Lilleskov, Elias

    2016-07-01

    When a light bulb is turned on, light moves away from it at speed c, by definition. When light from this bulb illuminates a surface, however, this illumination front is not constrained to move at speed c. A simple proof is given that this illumination front always moves faster than c. Generalized, when any compact light source itself varies, this information spreads across all of the surfaces it illuminates at speeds faster than light.

  4. Surface modification of solids

    SciTech Connect

    Appleton, B.R.

    1984-05-01

    The use of ion beam and pulsed laser processing is reviewed for the near-surface modification of a wide range of materials. The techniques of ion implantation doping, ion beam and laser mixing, and pulsed-laser annealing are stressed with particular emphasis on the nonequilibrium aspects of these processing techniques and on new materials properties which can result. Examples are presented illustrating the utility of these techniques for fundamental materials research as well as practical surface modifications.

  5. Designing Superoleophobic Surfaces (Postprint)

    DTIC Science & Technology

    2007-12-07

    apparent contact angles with water greater than 150 degrees and low contact angle hysteresis. However, superoleophobic surfaces—those that display...contact angles greater than 150 degrees with organic liquids having appreciably lower surface tensions than that of water —are extremely rare. Calculations...surfaces, which exhibit apparent contact angles with water greater than 150 degrees and low contact angle hysteresis. However, superoleophobic

  6. Surface Deformation Image Analyzer

    DTIC Science & Technology

    2012-09-27

    such as MRI, positron emission tomography (PET) and ultrasound , provide Attorney Docket No. 101700 3 of 36 detailed images of abnormalities...the time frame and cost for treating non-healing wounds. SUMMARY OF THE INVENTION [0012] The present invention provides a device which includes...the surface of interest and the type of deformation anticipated; it may be helpful to treat the surface of interest with a heat source, such as

  7. Computer aided surface representation

    SciTech Connect

    Barnhill, R.E.

    1989-02-09

    The central research problem of this project is the effective representation and display of surfaces, interpolating to given information, in three or more dimensions. In a typical problem, we wish to create a surface from some discrete information. If this information is itself on another surface, the problem is to determine a surface defined on a surface,'' which is discussed below. Often, properties of an already constructed surface are desired: such geometry processing'' is described below. The Summary of Proposed Research from our original proposal describes the aims of this research project. This Summary and the Table of Contents from the original proposal are enclosed as an Appendix to this Progress Report. The broad sweep from constructive mathematics through algorithms and computer graphics displays is utilized in the research. The wide range of activity, directed in both theory and applications, makes this project unique. Last month in the first Ardent Titan delivered in the State of Arizona came to our group, funded by the DOE and Arizona State University. Although the Titan is a commercial product, its newness requires our close collaboration with Ardent to maximize results. During the past year, four faculty members and several graduate research assistants have worked on this DOE project. The gaining of new professionals is an important aspect of this project. A listing of the students and their topics is given in the Appendix. The most significant publication during the past year is the book, Curves and Surfaces for Computer Aided Geometric Design, by Dr. Gerald Farin. This 300 page volume helps fill a considerable gap in the subject and includes many new results on Bernstein-Bezier curves and surfaces.

  8. Surface roughness and runoff

    NASA Astrophysics Data System (ADS)

    Szabó, Judit Alexandra; Szabó, Boglárka; Centeri, Csaba; Józsa, Sándor; Szalai, Zoltán; Jakab, Gergely

    2017-04-01

    Soil surface conditions changes dynamically during a precipitation event. The changes involve compaction, aggregate detachment and of course transportation by runoff or drop erosion. Those processes together have an effect on the transport process of the soil particles and aggregates, and influences the roughness of the soil surface as well. How does surface roughness have an effect on the aggregate and particle size distribution of the sediment? How does the sediment connectivity change from precipitation event to precipitation event? Beside the previous questions on of the main aim of the present research is to apply rainfall simulators for the built-up of a complex approach, rather than to concentrate only on one of two factors. Hence four types of sample were collected during the simulation experiment sequences: 1) photos were taken about the surface before and after the rain, in order to build digital surface models; 2) all the runoff and eroded sediment was collected; 3) soil loss due to drop erosion was also sampled separately; and 4) undisturbed crust samples were collected for thin section analyses. Though the runoff ratio was smaller than what, the preliminary results suggest that the sediment connectivity covered bigger area on crusty surface, than on a rough one. These ambiguous data may be connected to the soil crust development. J. A. Szabó wish to acknowledge the support of NTP-NFTÖ-16-0203. G. Jakab wish to acknowledge the support of János Bolyai Fellowship.

  9. Surface Mediated Protein Disaggregation

    NASA Astrophysics Data System (ADS)

    Radhakrishna, Mithun; Kumar, Sanat K.

    2014-03-01

    Preventing protein aggregation is of both biological and industrial importance. Biologically these aggregates are known to cause amyloid type diseases like Alzheimer's and Parkinson's disease. Protein aggregation leads to reduced activity of the enzymes in industrial applications. Inter-protein interactions between the hydrophobic residues of the protein are known to be the major driving force for protein aggregation. In the current paper we show how surface chemistry and curvature can be tuned to mitigate these inter-protein interactions. Our results calculated in the framework of the Hydrophobic-Polar (HP) lattice model show that, inter-protein interactions can be drastically reduced by increasing the surface hydrophobicity to a critical value corresponding to the adsorption transition of the protein. At this value of surface hydrophobicity, proteins lose inter-protein contacts to gain surface contacts and thus the surface helps in reducing the inter-protein interactions. Further, we show that the adsorption of the proteins inside hydrophobic pores of optimal sizes are most efficient both in reducing inter-protein contacts and simultaneously retaining most of the native-contacts due to strong protein-surface interactions coupled with stabilization due to the confinement. Department of Energy (Grant No DE-FG02-11ER46811).

  10. Hydrogen at Polymer Surfaces

    SciTech Connect

    Zemek, J.; Houdkova, J.; Lesiak, B.

    2010-06-02

    We present a relatively simple method for analyzing H content on surfaces of selected commercially available polymers, i.e. polyethylene, polypropylene, polystyrene, and poly(methylphenylsilylene). The applied method, i.e. the Elastic Peak Electron Spectroscopy (EPES), is based on quasi-elastic scattering of primary beam electrons with atoms of solid sample constituents. Electron energy, scattering angle and difference between electron mass and atomic mass of sample constituents induces an electron recoil energy loss. Recoil effect results of splitting the elastic peak into components, by their energy shifting and broadening. For above-mentioned polymers, the EPES method indicates the surface H content close to the nominal composition. Sampling depth of the method does not exceed inelastic mean free path of electrons used in the scattering experiment. Therefore, the technique is useful to monitor H surface content during or after various surface modifications as UV, electron and ion beam modification of polymer surfaces or surface plasma treatments. Limitations of the technique are mentioned.

  11. Quantifying surface normal estimation

    NASA Astrophysics Data System (ADS)

    Reid, Robert B.; Oxley, Mark E.; Eismann, Michael T.; Goda, Matthew E.

    2006-05-01

    An inverse algorithm for surface normal estimation from thermal polarimetric imagery was developed and used to quantify the requirements on a priori information. Building on existing knowledge that calculates the degree of linear polarization (DOLP) and the angle of polarization (AOP) for a given surface normal in a forward model (from an object's characteristics to calculation of the DOLP and AOP), this research quantifies the impact of a priori information with the development of an inverse algorithm to estimate surface normals from thermal polarimetric emissions in long-wave infrared (LWIR). The inverse algorithm assumes a polarized infrared focal plane array capturing LWIR intensity images which are then converted to Stokes vectors. Next, the DOLP and AOP are calculated from the Stokes vectors. Last, the viewing angles, θ v, to the surface normals are estimated assuming perfect material information about the imaged scene. A sensitivity analysis is presented to quantitatively describe the a priori information's impact on the amount of error in the estimation of surface normals, and a bound is determined given perfect information about an object. Simulations explored the impact of surface roughness (σ) and the real component (n) of a dielectric's complex index of refraction across a range of viewing angles (θ v) for a given wavelength of observation.

  12. Lunar Surface Operations. Part 2; Surface Duration

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael

    2009-01-01

    The objectives of this slide presentation are to review the activities on the lunar surface during the stay. The objectives include (1) Summarize Lunar Module Basics emphasizing module layout and storage. (2) Identify the primary activities occurring during each of the lunar s urface timelines, (3) List the EVA Prep tasks, (4) Identify the EVA Objectives, (5) Identify the activities associated with Post EVA (6) Describe the lessons learned during both EVA and Non EVA activities. Included are overview drawings of the Lunar Roving Vehicle, pictures of the tools, and sample return containers. There are also time lines for the Apollo 11, and Apollo 12 through 14, Apollo 15, Apollo 16 and Apollo 17. Diagrams of the EVA suits are shown, including the Liquid Cooling Garment, and the Pressure Garment Assembly. The activity prior to the EVA are reviewed. The science mission assignments of each mission are viewed. The activities after the EVA are reviewed

  13. Surface plasma wave applications

    SciTech Connect

    Fontana, E.

    1989-01-01

    Surface plasma waves (SPWs) are electromagnetic oscillations that occur at the interface between a metal and a dielectric medium. The wave amplitude reaches a maximum at the interface and decays exponentially along the normal direction within each medium, with a decaying length on the order of a wavelength. Because SPW excitation is a resonant phenomenon which is strongly dependent on the boundary conditions, SPWs are sensitive probes of optical and structural properties of the interface, allowing, by means of visible light, the detection of changes of sub-angstrom dimensions in thin films covering a metal surface. The resonant nature of the excitation also leads to a wave intensity two to three orders of magnitude higher than the intensity produced by a conventional electromagnetic wave striking a metal surface. Therefore, light scattering from surface irregularities can be enhanced by the same factor under SPW excitation, and structural information can be obtained. Measurement of SPW basic parameters such as amplitude, velocity and damping is achieved using simple optical procedures. These procedures are described and applied in this thesis for the characterization of multilayer rough surfaces and for the simultaneous determination of coating thickness and substrate optical constants of dielectric-coated, metal mirrors. These applications are relevant in the diagnosis of optical and structural properties of thin films. We also use the high sensitivity of SPWs to the presence of very thin coatings to design a surface plasmon immunoassay (SPI) for monitoring immunochemical reactions occurring nearby a metal surface. In particular, the SPI can be used as a simple and rapid procedure to determine antibody levels in blood serum, which is of interest in the field of immunology.

  14. Mars Surface Environmental Issues

    NASA Technical Reports Server (NTRS)

    Charles, John

    2002-01-01

    Planetary exploration by astronauts will require extended periods of habitation on a planet's surface, under the influence of environmental factors that are different from those of Earth and the spacecraft that delivered the crew to the planet. Human exploration of Mars, a possible near-term planetary objective, can be considered a challenging scenario. Mission scenarios currently under consideration call for surface habitation periods of from 1 to 18 months on even the earliest expeditions. Methods: Environmental issues associated with Mars exploration have been investigated by NASA and the National Space Biomedical Research Institute (NSBRI) as part of the Bioastronautics Critical Path Roadmap Project (see http ://criticalpath.jsc.nasa.gov). Results: Arrival on Mars will immediately expose the crew to gravity only 38% of that at Earth's surface in possibly the first prolonged exposure to gravity other than the 1G of Earth's surface and the zero G of weightless space flight, with yet unknown effects on crew physiology. The radiation at Mars' surface is not well documented, although the planet's bulk and even its thin atmosphere may moderate the influx of galactic cosmic radiation and energetic protons from solar flares. Secondary radiation from activated components of the soil must also be considered. Ultrafine and larger respirable and nonrespirable particles in Martian dust introduced into the habitat after surface excursions may induce pulmonary inflammation exacerbated by the additive reactive and oxidizing nature of the dust. Stringent decontamination cannot eliminate mechanical and corrosive effects of the dust on pressure suits and exposed machinery. The biohazard potential of putative indigenous Martian microorganisms may be assessed by comparison with analog environments on Earth. Even in their absence, human microorganisms, if not properly controlled, can be a threat to the crew's health. Conclusions: Mars' surface offers a substantial challenge to the

  15. In Situ Surface Characterization

    NASA Technical Reports Server (NTRS)

    Deen, Robert G.; Leger, Patrick C.; Yanovsky, Igor

    2011-01-01

    Operation of in situ space assets, such as rovers and landers, requires operators to acquire a thorough understanding of the environment surrounding the spacecraft. The following programs help with that understanding by providing higher-level information characterizing the surface, which is not immediately obvious by just looking at the XYZ terrain data. This software suite covers three primary programs: marsuvw, marsrough, and marsslope, and two secondary programs, which together use XYZ data derived from in situ stereo imagery to characterize the surface by determining surface normal, surface roughness, and various aspects of local slope, respectively. These programs all use the Planetary Image Geometry (PIG) library to read mission-specific data files. The programs themselves are completely multimission; all mission dependencies are handled by PIG. The input data consists of images containing XYZ locations as derived by, e.g., marsxyz. The marsuvw program determines surface normals from XYZ data by gathering XYZ points from an area around each pixel and fitting a plane to those points. Outliers are rejected, and various consistency checks are applied. The result shows the orientation of the local surface at each point as a unit vector. The program can be run in two modes: standard, which is typically used for in situ arm work, and slope, which is typically used for rover mobility. The difference is primarily due to optimizations necessary for the larger patch sizes in the slope case. The marsrough program determines surface roughness in a small area around each pixel, which is defined as the maximum peak-to-peak deviation from the plane perpendicular to the surface normal at that pixel. The marsslope program takes a surface normal file as input and derives one of several slope-like outputs from it. The outputs include slope, slope rover direction (a measure of slope radially away from the rover), slope heading, slope magnitude, northerly tilt, and solar energy

  16. Asteroid Surface Geophysics

    NASA Astrophysics Data System (ADS)

    Murdoch, N.; Sánchez, P.; Schwartz, S. R.; Miyamoto, H.

    The regolith-covered surfaces of asteroids preserve records of geophysical processes that have occurred both at their surfaces and sometimes also in their interiors. As a result of the unique microgravity environment that these bodies possess, a complex and varied geophysics has given birth to fascinating features that we are just now beginning to understand. The processes that formed such features were first hypothesized through detailed spacecraft observations and have been further studied using theoretical, numerical, and experimental methods that often combine several scientific disciplines. These multiple approaches are now merging toward a further understanding of the geophysical states of the surfaces of asteroids. In this chapter we provide a concise summary of what the scientific community has learned so far about the surfaces of these small planetary bodies and the processes that have shaped them. We also discuss the state of the art in terms of experimental techniques and numerical simulations that are currently being used to investigate regolith processes occurring on small-body surfaces and that are contributing to the interpretation of observations and the design of future space missions.

  17. Stability of surface nanobubbles

    NASA Astrophysics Data System (ADS)

    Maheshwari, Shantanu; van der Hoef, Martin; Zhang, Xuehua; Lohse, Detlef

    2015-11-01

    We have studied the stability and dissolution of surface nanobubbles on the chemical heterogenous surface by performing Molecular Dynamics (MD) simulations of binary mixture consists of Lennard-Jones (LJ) particles. Recently our group has derived the exact expression for equilibrium contact angle of surface nanobubbles as a function of oversaturation of the gas concentration in bulk liquid and the lateral length of bubble. It has been showed that the contact line pinning and the oversaturation of gas concentration in bulk liquid is crucial in the stability of surface nanobubbles. Our simulations showed that how pinning of the three-phase contact line on the chemical heterogenous surface lead to the stability of the nanobubble. We have calculated the equilibrium contact angle by varying the gas concentration in bulk liquid and the lateral length of the bubble. Our results showed that the equilibrium contact angle follows the expression derived analytically by our group. We have also studied the bubble dissolution dynamics and showed the ''stick-jump'' mechanism which was also observed experimentally in case of dissolution of nanodrops.

  18. Defects at semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Henzler, Martin

    1985-04-01

    Low Energy Electron Diffraction (LEED) is widely used for detection of periodicity at the surface and of atom arrangement within the unit cell. Experiments and results, however, are increasing, which use the spot profile analysis (SPA-LEED) for the study of nonperiodic surfaces. Here the kinematical approximation provides a wider range of validity than expected. For semiconductors defects are especially important, since the surface states in the gap are determined or strongly influenced by almost any kind of defects at the surface. Atomic steps at the interface {Si}/{SiO2} have been shown to be correlated with many electronic properties of MOS devices like mobility, interface states and fixed charge. The epitaxy on Si and GaAs has been studied with LEED and RHEED, showing the density of the nuclei during formation of a layer and the layer-by-layer growth. The formation of metal suicides in the monolayer range is accompanied by many different superstructures and other rearrangements. It is demonstrated, that the new high resolution instruments provide additional qualitative and quantitative informations on any kind of surface defects.

  19. Surface inspection operator interface

    NASA Astrophysics Data System (ADS)

    Creek, Russell C.

    1992-03-01

    Surface inspection systems are widely used in many industries including steel, tin, aluminum, and paper. These systems generally use machine vision technology to detect defective surface regions and can generate very high data output rates which can be difficult for line operators to absorb and use. A graphical, windowing interface is described which provides the operators with an overview of the surface quality of the inspected web while still allowing them to select individual defective regions for display. A touch screen is used as the only operator input. This required alterations to some screen widgets due to subtle ergonomic differences of touch screen input over mouse input. The interface, although developed for inspecting coated steel, has been designed to be adaptable to other surface inspection applications. Facility is provided to allow the detection, classification, and display functions of the inspection system to be readily changed. Modifications can be implemented on two main levels; changes that reflect the configuration of the hardware system and control the detection and classification components of the surface inspection system are accessible only to authorized staff while those affecting the display and alarm settings of defect types may be changed by operators and this can generally be done dynamically.

  20. Surface treatments by laser

    NASA Astrophysics Data System (ADS)

    Thomann, A. L.; Benzerga, R.; Basillais, Armelle; Georges, Cecile; Fariaut, Francois; Semmar, Nadjib; Boulmer-Leborgne, Chantal

    2003-07-01

    Laser treatments of various metals are studying depending on the laser wavelength, pulse time duration and shape, and fluence (laser/metal interaction regime). Low fluence excimer UV laser melting process of gold layer is shown to improve the corrosion resistance of multilayer (Au/Ni/Cu alloy) electrical contacts. For this application the homogenity of the laser beam as well as the initial Cu substrate roughness are found to be limiting parameters of the process. Carburization of Al alloy, performed in C3H6 atmosphere with a KrF laser induces the incorporation of carbon atoms over about 4 μm depth. The crystalline Al4C3 synthesized at the surface leads to a strengthening of the light Al alloy, which is of great interest for application in car industry. The study shows that diffusion of C atom in the target is possible because of a plasma presence on the surface which supports the molten bath life time and induces dissociation of the ambient gas. In the last example of laser metal surface treatment presented in that paper, a commonly used steel is treated in air with different lasers at a fluence above the plasma formation threshold. It is seen that the machining oils covering the surface before the treatment can be efficiently removed and that new compounds (nitride, carbide and oxides) are formed at the surface.

  1. Surface roughness measurements

    NASA Astrophysics Data System (ADS)

    Howard, Thomas G.

    1994-10-01

    The Optics Division is currently in the research phase of producing grazing-incidence mirrors to be used in x-ray detector applications. The traditional method of construction involves labor-intensive glass grinding. This also culminates in a relatively heavy mirror. For lower resolution applications, the mirrors may be of a replicated design which involves milling a mandrel as a negative of the final shape and electroplating the cylindrical mirror onto it. The mirror is then separated from the mandrel by cooling. The mandrel will shrink more than the 'shell' (mirror) allowing it to be pulled from the mandrel. Ulmer (2) describes this technique and its variations in more detail. To date, several mirrors have been tested at MSFC by the Optical Fabrication Branch by focusing x-ray energy onto a detector with limited success. Little is known about the surface roughness of the actual mirror. Hence, the attempt to gather data on these surfaces. The test involves profiling the surface of a sample, replicating the surface as described above, and then profiling the replicated surface.

  2. Epidermal surface lipids.

    PubMed

    Pappas, Apostolos

    2009-03-01

    A layer of lipids, which are of both sebaceous and keratinocyte origin, covers the surface of the skin. The apparent composition of surface lipids varies depending on the selected method of sampling. Lipids produced by the epidermal cells are an insignificant fraction of the total extractable surface lipid on areas rich in sebaceous glands. Due to the holocrine activity of the sebaceous gland, its product of secretion (sebum) is eventually released to the surface of the skin and coats the fur as well. Lipids of epidermal origin fill the spaces between the cells, like mortar or cement. The sebaceous lipids are primarily non polar lipids as triglycerides, wax esters and squalene, while epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol. The composition of the sebaceous lipids is unique and intriguing and elevated sebum excretion is a major factor involved in the pathophysiology of acne. Recent studies have elucidated the roles that epidermal surface lipids have on normal skin functions and acne.

  3. Interstellar Grain Surface Chemistry

    NASA Technical Reports Server (NTRS)

    Tielens, Alexander G. G. M.; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    Chemistry on grain surfaces plays an Important role in the formation of interstellar Ices, It can also influence the composition of the gas phase through outgassing near luminous, newly formed stars. This paper reviews the chemical processes taking place on Interstellar grain surfaces with the emphasis on those transforming CO into other hydrocarbons. At low, molecular cloud temperatures (approximately equal to 10K), physisorption processes dominate interstellar grain surface chemistry and GO is largely hydrogenated through reactions with atomic H and oxidized through reactions with atomic O. The former will lead to the formation of H2CO and CH3OH ices, while the latter results in CO2 ice. The observational evidence for these ices in molecular clouds will be discussed. Very close to protostars, the gas and grain temperatures are much higher (approximately equal to 500K) and chemisorption processes, including catalytic surface reactions, becomes important. This will be illustrated based upon our studies of the Fischer-Tropsch Synthesis of CH4 from CO on metallic surfaces. Likely, this process has played an important role in the early solar nebula. Observational consequences will be pointed out.

  4. Anticipating land surface change

    PubMed Central

    Streeter, Richard; Dugmore, Andrew J.

    2013-01-01

    The interplay of human actions and natural processes over varied spatial and temporal scales can result in abrupt transitions between contrasting land surface states. Understanding these transitions is a key goal of sustainability science because they can represent abrupt losses of natural capital. This paper recognizes flickering between alternate land surface states in advance of threshold change and critical slowing down in advance of both threshold changes and noncritical transformation. The early warning signals we observe are rises in autocorrelation, variance, and skewness within millimeter-resolution thickness measurements of tephra layers deposited in A.D. 2010 and A.D. 2011. These signals reflect changing patterns of surface vegetation, which are known to provide early warning signals of critical transformations. They were observed toward migrating soil erosion fronts, cryoturbation limits, and expanding deflation zones, thus providing potential early warning signals of land surface change. The record of the spatial patterning of vegetation contained in contemporary tephra layers shows how proximity to land surface change could be assessed in the widespread regions affected by shallow layers of volcanic fallout (those that can be subsumed within the existing vegetation cover). This insight shows how we could use tephra layers in the stratigraphic record to identify “near misses,” close encounters with thresholds that did not lead to tipping points, and thus provide additional tools for archaeology, sustainability science, and contemporary land management. PMID:23530230

  5. Epidermal surface lipids

    PubMed Central

    2009-01-01

    A layer of lipids, which are of both sebaceous and keratinocyte origin, covers the surface of the skin. The apparent composition of surface lipids varies depending on the selected method of sampling. Lipids produced by the epidermal cells are an insignificant fraction of the total extractable surface lipid on areas rich in sebaceous glands. Due to the holocrine activity of the sebaceous gland, its product of secretion (sebum) is eventually released to the surface of the skin and coats the fur as well. Lipids of epidermal origin fill the spaces between the cells, like mortar or cement. The sebaceous lipids are primarily non polar lipids as triglycerides, wax esters and squalene, while epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol. The composition of the sebaceous lipids is unique and intriguing and elevated sebum excretion is a major factor involved in the pathophysiology of acne. Recent studies have elucidated the roles that epidermal surface lipids have on normal skin functions and acne. PMID:20224687

  6. Anticipating land surface change.

    PubMed

    Streeter, Richard; Dugmore, Andrew J

    2013-04-09

    The interplay of human actions and natural processes over varied spatial and temporal scales can result in abrupt transitions between contrasting land surface states. Understanding these transitions is a key goal of sustainability science because they can represent abrupt losses of natural capital. This paper recognizes flickering between alternate land surface states in advance of threshold change and critical slowing down in advance of both threshold changes and noncritical transformation. The early warning signals we observe are rises in autocorrelation, variance, and skewness within millimeter-resolution thickness measurements of tephra layers deposited in A.D. 2010 and A.D. 2011. These signals reflect changing patterns of surface vegetation, which are known to provide early warning signals of critical transformations. They were observed toward migrating soil erosion fronts, cryoturbation limits, and expanding deflation zones, thus providing potential early warning signals of land surface change. The record of the spatial patterning of vegetation contained in contemporary tephra layers shows how proximity to land surface change could be assessed in the widespread regions affected by shallow layers of volcanic fallout (those that can be subsumed within the existing vegetation cover). This insight shows how we could use tephra layers in the stratigraphic record to identify "near misses," close encounters with thresholds that did not lead to tipping points, and thus provide additional tools for archaeology, sustainability science, and contemporary land management.

  7. The generation of surface targets with specified surface statistics

    NASA Technical Reports Server (NTRS)

    Rochier, J. D.; Blanchard, A. J.; Chen, M. F.

    1989-01-01

    Results are presented from efforts to generate physical surfaces from known or desired surface statistical properties, proceeding from previous work on the generation of random surfaces for use in computer simulations. The known statistical surface is extended using a bicubic spline technique; these results are interfaced with a numerically controlled machine in order to generate the physical surface. A portion of a complete surface with Gaussian statistics was constructed and tested to measure conformity to the desired statistics.

  8. Host preferences of arbuscular mycorrhizal fungi colonizing annual herbaceous plant species in semiarid Mediterranean prairies.

    PubMed

    Torrecillas, E; Alguacil, M M; Roldán, A

    2012-09-01

    In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems.

  9. Assessment of the food habits of the Moroccan dorcas gazelle in M'Sabih Talaa, west central Morocco, using the trnL approach.

    PubMed

    Ait Baamrane, Moulay Abdeljalil; Shehzad, Wasim; Ouhammou, Ahmed; Abbad, Abdelaziz; Naimi, Mohamed; Coissac, Eric; Taberlet, Pierre; Znari, Mohammed

    2012-01-01

    Food habits of the Moroccan dorcas gazelle, Gazella dorcas massaesyla, previously investigated in the 1980s using microhistological fecal analysis, in the M'Sabih Talaa Reserve, west central Morocco, were re-evaluated over three seasons (spring, summer and autumn 2009) using the trnL approach to determine the diet composition and its seasonal variation from fecal samples. Taxonomic identification was carried out using the identification originating from the database built from EMBL and the list of plant species within the reserve. The total taxonomic richness in the reserve was 130 instead of 171 species in the 1980s. The diet composition revealed to be much more diversified (71 plant taxa belonging to 57 genus and 29 families) than it was 22 years ago (29 identified taxa). Thirty-four taxa were newly identified in the diet while 13 reported in 1986-87 were not found. Moroccan dorcas gazelle showed a high preference to Acacia gummifera, Anagallis arvensis, Glebionis coronaria, Cladanthus arabicus, Diplotaxis tenuisiliqua, Erodium salzmannii, Limonium thouini, Lotus arenarius and Zizyphus lotus. Seasonal variations occurred in both number (40-41 taxa in spring-summer and 49 taxa in autumn vs. respectively 23-22 and 26 in 1986-1987) and taxonomic type of eaten plant taxa. This dietary diversification could be attributed either to the difference in methods of analysis, trnL approach having a higher taxonomic resolution, or a potential change in nutritional quality of plants over time.

  10. Medicinal plants used for dermatological affections in Navarra and their pharmacological validation.

    PubMed

    Cavero, R Y; Akerreta, S; Calvo, M I

    2013-09-16

    This paper provides significant ethnopharmacological information on plant used in dermatological affections in Navarra. Information was collected using semi-structured ethnobotanical interviews with 667 informants (mean age 72; 55.47% women, 44.53% men) in 265 locations. In order to confirm the pharmacological validation of the uses reports, the European Scientific Cooperative on Phytotherapy (ESCOP), German Commission E, World Health Organization (WHO), European Medicines Agency (EMA), European Pharmacopoeia (Ph. Eur.) and Real Farmacopea Española (RFE) monographs have been revised. A literature review has been carried out with the plants without monograph and high frequency citations, using a new tool of the University of Navarra, UNIKA. A total of 982 pharmaceutical uses are reported from the informants, belonging to 91 plants and 42 families, mainly represented by Asteraceae, Lamiaceae, Euphorbiaceae and Crassulaceae. The most frequently used parts of the plants are aerial parts followed by leaves and inflorescences. Seventeen out of 91 plants (19%) and 148 of 982 popular uses (15%), have already been pharmacologically validated. The authors propose seven species for their validation (Allium cepa, Sambucus nigra, Hylotelephium maximum, Chelidonium majus, Ficus carica, Allium sativum and Anagallis arvensis). © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Host Preferences of Arbuscular Mycorrhizal Fungi Colonizing Annual Herbaceous Plant Species in Semiarid Mediterranean Prairies

    PubMed Central

    Torrecillas, E.; Roldán, A.

    2012-01-01

    In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems. PMID:22752164

  12. Assessment of the Food Habits of the Moroccan Dorcas Gazelle in M’Sabih Talaa, West Central Morocco, Using the trnL Approach

    PubMed Central

    Ait Baamrane, Moulay Abdeljalil; Shehzad, Wasim; Ouhammou, Ahmed; Abbad, Abdelaziz; Naimi, Mohamed; Coissac, Eric; Taberlet, Pierre; Znari, Mohammed

    2012-01-01

    Food habits of the Moroccan dorcas gazelle, Gazella dorcas massaesyla, previously investigated in the 1980s using microhistological fecal analysis, in the M’Sabih Talaa Reserve, west central Morocco, were re-evaluated over three seasons (spring, summer and autumn 2009) using the trnL approach to determine the diet composition and its seasonal variation from fecal samples. Taxonomic identification was carried out using the identification originating from the database built from EMBL and the list of plant species within the reserve. The total taxonomic richness in the reserve was 130 instead of 171 species in the 1980s. The diet composition revealed to be much more diversified (71 plant taxa belonging to 57 genus and 29 families) than it was 22 years ago (29 identified taxa). Thirty-four taxa were newly identified in the diet while 13 reported in 1986–87 were not found. Moroccan dorcas gazelle showed a high preference to Acacia gummifera, Anagallis arvensis, Glebionis coronaria, Cladanthus arabicus, Diplotaxis tenuisiliqua, Erodium salzmannii, Limonium thouini, Lotus arenarius and Zizyphus lotus. Seasonal variations occurred in both number (40–41 taxa in spring-summer and 49 taxa in autumn vs. respectively 23–22 and 26 in 1986–1987) and taxonomic type of eaten plant taxa. This dietary diversification could be attributed either to the difference in methods of analysis, trnL approach having a higher taxonomic resolution, or a potential change in nutritional quality of plants over time. PMID:22558187

  13. Iron oxide surfaces

    NASA Astrophysics Data System (ADS)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  14. Dual surface interferometer

    DOEpatents

    Pardue, R.M.; Williams, R.R.

    1980-09-12

    A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarterwave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

  15. Dual surface interferometer

    DOEpatents

    Pardue, Robert M.; Williams, Richard R.

    1982-01-01

    A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

  16. Surface-water surveillance

    SciTech Connect

    Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

  17. Uranus satellites - Surface properties

    NASA Astrophysics Data System (ADS)

    Veverka, J.; Brown, R. H.; Bell, Jeffrey F.

    The post-Voyager knowledge of the photometric, colorimetric, spectral, and thermal properties of the Uranian satellites is reviewed, focusing on such fundamental physical properties as albedo, color, and surface texture. While albedo variations of at least a factor of 2 exist, color differences are almost absent (Miranda) or subdued (Oberon). In the case of Titania, the strong opposition effect reported by ground-based observers was confirmed by Voyager. Voyager did not observe the opposition parts of the phase curves of the other satellites. Voyager thermal observations of Ariel and Miranda suggest that both have highly porous regoliths, thermophysically similar to those of Jupiter's icy satellites. At the time of the flyby (south pole facing the sun), maximum surface temperatures reached or exceeded 85 K, but nighttime polar temperatures are predicted to drop to 20 to 30 K because each pole spends about 40 yr in darkness. Ground-based spectroscopy identified water ice as an important surface constituent.

  18. Uranus satellites - Surface properties

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Brown, R. H.; Bell, Jeffrey F.

    1991-01-01

    The post-Voyager knowledge of the photometric, colorimetric, spectral, and thermal properties of the Uranian satellites is reviewed, focusing on such fundamental physical properties as albedo, color, and surface texture. While albedo variations of at least a factor of 2 exist, color differences are almost absent (Miranda) or subdued (Oberon). In the case of Titania, the strong opposition effect reported by ground-based observers was confirmed by Voyager. Voyager did not observe the opposition parts of the phase curves of the other satellites. Voyager thermal observations of Ariel and Miranda suggest that both have highly porous regoliths, thermophysically similar to those of Jupiter's icy satellites. At the time of the flyby (south pole facing the sun), maximum surface temperatures reached or exceeded 85 K, but nighttime polar temperatures are predicted to drop to 20 to 30 K because each pole spends about 40 yr in darkness. Ground-based spectroscopy identified water ice as an important surface constituent.

  19. Surface matching via currents.

    PubMed

    Vaillant, Marc; Glaunès, Joan

    2005-01-01

    We present a new method for computing an optimal deformation between two arbitrary surfaces embedded in Euclidean 3-dimensional space. Our main contribution is in building a norm on the space of surfaces via representation by currents of geometric measure theory. Currents are an appropriate choice for representations because they inherit natural transformation properties from differential forms. We impose a Hilbert space structure on currents, whose norm gives a convenient and practical way to define a matching functional. Using this Hilbert space norm, we also derive and implement a surface matching algorithm under the large deformation framework, guaranteeing that the optimal solution is a one-to-one regular map of the entire ambient space. We detail an implementation of this algorithm for triangular meshes and present results on 3D face and medical image data.

  20. Analytical caustic surfaces

    NASA Technical Reports Server (NTRS)

    Schmidt, R. F.

    1987-01-01

    This document discusses the determination of caustic surfaces in terms of rays, reflectors, and wavefronts. Analytical caustics are obtained as a family of lines, a set of points, and several types of equations for geometries encountered in optics and microwave applications. Standard methods of differential geometry are applied under different approaches: directly to reflector surfaces, and alternatively, to wavefronts, to obtain analytical caustics of two sheets or branches. Gauss/Seidel aberrations are introduced into the wavefront approach, forcing the retention of all three coefficients of both the first- and the second-fundamental forms of differential geometry. An existing method for obtaining caustic surfaces through exploitation of the singularities in flux density is examined, and several constant-intensity contour maps are developed using only the intrinsic Gaussian, mean, and normal curvatures of the reflector. Numerous references are provided for extending the material of the present document to the morphologies of caustics and their associated diffraction patterns.

  1. Solid surface luminescence analysis

    NASA Astrophysics Data System (ADS)

    Hurtubise, R. J.

    1984-04-01

    Several advances were made in understanding the interactions responsible for room-temperature phosphorescence. Infrared data showed strong room-temperature phosphorescence from compounds adsorbed on some surfaces which contained adsorbed water. A partial model for phosphor/solid-surface interactions was developed for nitrogen heterocycles and polycyclic aromatic hydrocarbons adsorbed on poly(acrylic acid)-salt mixtures. Hydroxyl aromatics behave as hydrogen donors, hydrogen accepting species, or as both hydrogen donors and hydrogen acceptors when adsorbed on solid-surfaces. Several new analytical methods and techniques were developed. Poly(acrylic acid)-phosphor solutions that were spotted on filter paper resulted in lower limits of detection and better reproducibility. Both qualitative and quantitative analysis of mixtures were achieved at the nanogram level by using room-temperature fluorescence and phosphorescence. In addition, the combined use of zeroth and second derivative room-temperature fluorescence and phosphorescence spectra was developed into a useful analytical approach.

  2. Controlled multibubble surface cavitation.

    PubMed

    Bremond, Nicolas; Arora, Manish; Ohl, Claus-Dieter; Lohse, Detlef

    2006-06-09

    Heterogeneous bubble nucleation at surfaces has been notorious because of its irreproducibility. Here controlled multibubble surface cavitation is achieved by using a hydrophobic surface patterned with microcavities. The expansion of the nuclei in the microcavities is triggered by a fast lowering of the liquid pressure. The procedure allows us to control and fix the bubble distance within the bubble cluster. We observe a perfect quantitative reproducibility of the cavitation events where the inner bubbles in the two-dimensional cluster are shielded by the outer ones, reflected by their later expansion and their delayed collapse. Apart from the final bubble collapse phase (when jetting flows directed towards the cluster's center develop), the bubble dynamics can be quantitatively described by an extended Rayleigh-Plesset equation, taking pressure modification through the surrounding bubbles into account.

  3. Controlled Multibubble Surface Cavitation

    NASA Astrophysics Data System (ADS)

    Bremond, Nicolas; Arora, Manish; Ohl, Claus-Dieter; Lohse, Detlef

    2006-06-01

    Heterogeneous bubble nucleation at surfaces has been notorious because of its irreproducibility. Here controlled multibubble surface cavitation is achieved by using a hydrophobic surface patterned with microcavities. The expansion of the nuclei in the microcavities is triggered by a fast lowering of the liquid pressure. The procedure allows us to control and fix the bubble distance within the bubble cluster. We observe a perfect quantitative reproducibility of the cavitation events where the inner bubbles in the two-dimensional cluster are shielded by the outer ones, reflected by their later expansion and their delayed collapse. Apart from the final bubble collapse phase (when jetting flows directed towards the cluster’s center develop), the bubble dynamics can be quantitatively described by an extended Rayleigh-Plesset equation, taking pressure modification through the surrounding bubbles into account.

  4. Neonatal Pial Surface Electroporation

    PubMed Central

    Levy, Rachelle; Molina, Jessica

    2014-01-01

    Over the past several years the pial surface has been identified as a germinal niche of importance during embryonic, perinatal and adult neuro- and gliogenesis, including after injury. However, methods for genetically interrogating these progenitor populations and tracking their lineages had been limited owing to a lack of specificity or time consuming production of viruses. Thus, progress in this region has been relatively slow with only a handful of investigations of this location. Electroporation has been used for over a decade to study neural stem cell properties in the embryo, and more recently in the postnatal brain. Here we describe an efficient, rapid, and simple technique for the genetic manipulation of pial surface progenitors based on an adapted electroporation approach. Pial surface electroporation allows for facile genetic labeling and manipulation of these progenitors, thus representing a time-saving and economical approach for studying these cells. PMID:24836046

  5. Neonatal pial surface electroporation.

    PubMed

    Levy, Rachelle; Molina, Jessica; Danielpour, Moise; Breunig, Joshua J

    2014-05-07

    Over the past several years the pial surface has been identified as a germinal niche of importance during embryonic, perinatal and adult neuro- and gliogenesis, including after injury. However, methods for genetically interrogating these progenitor populations and tracking their lineages had been limited owing to a lack of specificity or time consuming production of viruses. Thus, progress in this region has been relatively slow with only a handful of investigations of this location. Electroporation has been used for over a decade to study neural stem cell properties in the embryo, and more recently in the postnatal brain. Here we describe an efficient, rapid, and simple technique for the genetic manipulation of pial surface progenitors based on an adapted electroporation approach. Pial surface electroporation allows for facile genetic labeling and manipulation of these progenitors, thus representing a time-saving and economical approach for studying these cells.

  6. Uranus satellites - Surface properties

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Brown, R. H.; Bell, Jeffrey F.

    1991-01-01

    The post-Voyager knowledge of the photometric, colorimetric, spectral, and thermal properties of the Uranian satellites is reviewed, focusing on such fundamental physical properties as albedo, color, and surface texture. While albedo variations of at least a factor of 2 exist, color differences are almost absent (Miranda) or subdued (Oberon). In the case of Titania, the strong opposition effect reported by ground-based observers was confirmed by Voyager. Voyager did not observe the opposition parts of the phase curves of the other satellites. Voyager thermal observations of Ariel and Miranda suggest that both have highly porous regoliths, thermophysically similar to those of Jupiter's icy satellites. At the time of the flyby (south pole facing the sun), maximum surface temperatures reached or exceeded 85 K, but nighttime polar temperatures are predicted to drop to 20 to 30 K because each pole spends about 40 yr in darkness. Ground-based spectroscopy identified water ice as an important surface constituent.

  7. Hot Billet Surface Qualifier

    SciTech Connect

    Tzyy-Shuh Chang

    2007-04-30

    OG Technologies, Inc. (OGT), developed a prototype of a Hot Billet Surface Qualifier (“Qualifier”) based on OGT’s patented HotEye™ technology and other proprietary imaging and computing technologies. The Qualifier demonstrated its ability of imaging the cast billets in line with high definition pictures, pictures capable of supporting the detection of surface anomalies on the billets. The detection will add the ability to simplify the subsequent process and to correct the surface quality issues in a much more timely and efficient manner. This is challenging due to the continuous casting environment, in which corrosive water, temperature, vibration, humidity, EMI and other unbearable factors exist. Each installation has the potential of 249,000 MMBTU in energy savings per year. This represents a cost reduction, reduced emissions, reduced water usage and reduced mill scale.

  8. Unidirectional superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Prakash, Manu; Bush, John

    2007-11-01

    It has long been known that the hairy, waxy cuticle of water-walking insects renders them water-repellent; they thus exhibit high static contact angles. We have recently demonstrated that by the virtue of the geometry and flexibility of the hair, the integument is also directionally anisotropic and so plays a key propulsive role. We here report our attempts to design and implement an analogous synthetic surface that exhibits unidirectional adhesion. The surface effectively acts like a fluidic-diode; allowing contact lines to advance in only one direction. When vibrated randomly, drops suspended on the surface advance in only one direction. Applications in valve-less pumps and drop transport in microfluidic devices are discussed.

  9. Perspectives on surface nanobubbles

    PubMed Central

    Zhang, Xuehua; Lohse, Detlef

    2014-01-01

    Materials of nanoscale size exhibit properties that macroscopic materials often do not have. The same holds for bubbles on the nanoscale: nanoscale gaseous domains on a solid-liquid interface have surprising properties. These include the shape, the long life time, and even superstability. Such so-called surface nanobubbles may have wide applications. This prospective article covers the basic properties of surface nanobubbles and gives several examples of potential nanobubble applications in nanomaterials and nanodevices. For example, nanobubbles can be used as templates or nanostructures in surface functionalization. The nanobubbles produced in situ in a microfluidic system can even induce an autonomous motion of the nanoparticles on which they form. Their formation also has implications for the fluid transport in narrow channels in which they form. PMID:25379084

  10. Changes on Titan's surface

    NASA Astrophysics Data System (ADS)

    Solomonidou, A.; Lopes, R. M. C.; Coustenis, A.; Malaska, M. J.; Sotin, C.; Rodriguez, S.; Janssen, M. A.; Drossart, P.; Lawrence, K. J.; Matsoukas, C. K.; Hirtzig, M.; Le Mouelic, S.; Jaumann, R.; Brown, R. H.; Bratsolis, E.

    2015-12-01

    Cassini's Visual and Infrared Mapping Spectrometer (VIMS) and the Titan Radar Mapper have investigated Titan's surface since 2004, unveiling a complex, dynamic and Earth-like surface. Understanding the distribution and interplay of geologic processes is important for constraining models of its interior, surface-atmospheric interactions, and climate evolution. We focus on understanding the origin of the major geomorphological units identified by Lopes et al. (2010, 2015) [1,2], Malaska et al. (2015) [3] and regions we studied in Solomonidou et al. (2014; 2015) [4,5]. Here, we investigate the nature of: Undifferentiated Plains, Hummocky/Mountainous terrains, candidate cryovolcanic sites, Labyrinth, and Dunes in terms of surface albedo behavior and spectral evolution with time to identify possible changes. Using a radiative transfer code, we find that temporal variations of surface albedo occur for some areas. Tui Regio and Sotra Patera, both candidate cryovolcanic regions, change with time, becoming darker and brighter respectively in surface albedo. In contrast, we find that the Undifferentiated Plains and the suggested evaporitic areas [6] in the equatorial regions do not present any significant changes. We are able to report the differences and similarities among the various regions and provide constraints on their chemical composition and specific processes of origin. Our results support the hypothesis that both endogenic and exogenic processes have played important roles in shaping Titan's geologic evolution. Such a variety of geologic processes and their relationship to the methane cycle make Titan important for astrobiology and habitability studies and particularly significant in solar system studies. [1] Lopes, R.M.C., et al.: Icarus, 205, 540-588, 2010; [2] Lopes, R.M.C., et al.: JGR, 118, 416-435, 2013; [3] Malaska, M., et al : Icarus, submitted, 2015;[4] Solomonidou et al.: JGR, 119, 1729-1747, 2014; [5] Solomonidou, A., et al.: In press, 2015; [6] Barnes

  11. Surface modification of bioceramics

    NASA Astrophysics Data System (ADS)

    Monkawa, Akira

    Hydroxyapatite [Ca10(PO4)6(OH)2, HAp] is a major inorganic component of bone and teeth tissues and has the excellent biocompatibility and high osteoconductivity. The interactions between HAp and protein or cell have been studied. The HAp related bioceramics such as bone substitute, coating substance of metal implants, inorganic-polymer composites, and cell culture. We described two methods; (1) surface modification of HAp using organosilane; (2) fabrication of HAp ultra-thin layer on gold surface for protein adsorption analyzed with QCM-D technique. The interfacial interaction between collagen and HAp in a nano-region was controlled by depositing the organosilane of n-octadecyltrimethoxysilane (ODS: -CH3) or aminopropyltriethoxysilane (APTS: -NH2) with a chemical vapor deposition method. The morphologies of collagen adsorbed on the surfaces of HAp and HAp deposited with APTS were similar, however that of the surface with ODS was apparently different, due to the hydrophobic interaction between the organic head group of -CH3 and residual groups of collagen. We present a method for coating gold quartz crystal microbalance with dissipation (QCM-D) sensor with ultra-thin layer of hydroxyapatite nanocrystals evenly covering and tightly bound to the surface. The hydroxyapatite sensor operated in liquid with high stability and sensitivity. The in-situ adsorption mechanism and conformational change of fibrinogen on gold, titanium and hydroxyapatite surfaces were investigated by QCM-D technique and Fourier-transform infrared spectroscopy. The study indicates that the hydroxyapatite sensor is applicable for qualitative and conformational analysis of protein adsorption.

  12. Safety Play Surfaces Buying Guide.

    ERIC Educational Resources Information Center

    Morris, Susan

    1990-01-01

    Describes standards for playing surfaces and characteristics of play surfaces made of organic loose material, inorganic loose material, and compact materials. Necessary site preparation is discussed. An extensive, annotated list of manufacturers of surfaces is included. (DR)

  13. Low surface brightness galaxies

    NASA Technical Reports Server (NTRS)

    Vanderhulst, J. M.; Deblok, W. J. G.; Mcgaugh, S. S.; Bothun, G. D.

    1993-01-01

    A program to investigate the properties of low surface brightness (LSB) galaxies involving surface photometry in U, B, V, R, I, and H-alpha, HI imaging with the Westerbork Synthesis Radio Telescope (WSRT) and the very large array (VLA) and spectrophotometry of H2 regions in LSB galaxies is underway. The goal is to verify the idea that LSB galaxies have low star formation rates because the local gas density falls below the critical density for star formation, and to study the stellar population and abundances in LSB galaxies. Such information should help understanding the evolutionary history of LSB galaxies. Some preliminary results are reported.

  14. Ellipsometric surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Hsu, Wei-Liang; Lee, Shu-Sheng; Lee, Chih-Kung

    2009-03-01

    We develop a new multifunctional optical biochip system that integrates an ellipsometer with a surface plasmon resonance (SPR) feature. This newly developed biochip biosensor, which we call ESPR for an ellipsometric SPR, provides us with a system to retrieve detailed information such as the optical properties of immobilized biomolecular monolayers, surface concentration variations of biomedical reactions, and kinetic affinity between biomolecules required for further biotech analysis. Our ESPR can also serve as both a research and development tool and a manufacturing tool for various biomedical applications.

  15. NIMS Ganymede Surface Map

    NASA Image and Video Library

    1998-03-26

    Galileo has eyes that can see more than ours can. By looking at what we call the infrared wavelengths, the NIMS (Near Infrared Mapping Spectrometer) instrument can determine what type and size of material is on the surface of a moon. Here, 3 images of Ganymede are shown. Left: Voyager's camera. Middle: NIMS, showing water ice on the surface. Dark is less water, bright is more. Right: NIMS, showing the locations of minerals in red, and the size of ice grains in shades of blue. http://photojournal.jpl.nasa.gov/catalog/PIA00500

  16. Surface controlled blade stabilizer

    DOEpatents

    Russell, Larry R.

    1983-01-01

    Drill string stabilizer apparatus, controllable to expand and retract entirely from the surface by control of drill string pressure, wherein increase of drill string pressure from the surface closes a valve to create a piston means which is moved down by drill string pressure to expand the stabilizer blades, said valve being opened and the piston moving upward upon reduction of drill string pressure to retract the stabilizer blades. Upward and downward movements of the piston and an actuator sleeve therebelow are controlled by a barrel cam acting between the housing and the actuator sleeve.

  17. Compliant layer chucking surface

    DOEpatents

    Blaedel, Kenneth L.; Spence, Paul A.; Thompson, Samuel L.

    2004-12-28

    A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

  18. Quantitative Hydrocarbon Surface Analysis

    NASA Technical Reports Server (NTRS)

    Douglas, Vonnie M.

    2000-01-01

    The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.

  19. Solid Surface Combustion Experiment

    NASA Image and Video Library

    1994-09-12

    STS064-10-011 (12 Sept. 1994) --- The Solid Surface Combustion Experiment (SSCE), designed to supply information on flame spread over solid fuel surfaces in the reduced-gravity environment of space, is pictured during flight day four operations. The middeck experiment measured the rate of spreading, the solid-phase temperature, and the gas-phase temperature of flames spreading over rectangular fuel beds. STS-64 marked the seventh trip into space for the Lewis Research Center experiment. Photo credit: NASA or National Aeronautics and Space Administration

  20. Surface Aesthetics and Analysis.

    PubMed

    Çakır, Barış; Öreroğlu, Ali Rıza; Daniel, Rollin K

    2016-01-01

    Surface aesthetics of an attractive nose result from certain lines, shadows, and highlights with specific proportions and breakpoints. Analysis emphasizes geometric polygons as aesthetic subunits. Evaluation of the complete nasal surface aesthetics is achieved using geometric polygons to define the existing deformity and aesthetic goals. The relationship between the dome triangles, interdomal triangle, facet polygons, and infralobular polygon are integrated to form the "diamond shape" light reflection on the nasal tip. The principles of geometric polygons allow the surgeon to analyze the deformities of the nose, define an operative plan to achieve specific goals, and select the appropriate operative technique.

  1. Photometric Lunar Surface Reconstruction

    NASA Technical Reports Server (NTRS)

    Nefian, Ara V.; Alexandrov, Oleg; Morattlo, Zachary; Kim, Taemin; Beyer, Ross A.

    2013-01-01

    Accurate photometric reconstruction of the Lunar surface is important in the context of upcoming NASA robotic missions to the Moon and in giving a more accurate understanding of the Lunar soil composition. This paper describes a novel approach for joint estimation of Lunar albedo, camera exposure time, and photometric parameters that utilizes an accurate Lunar-Lambertian reflectance model and previously derived Lunar topography of the area visualized during the Apollo missions. The method introduced here is used in creating the largest Lunar albedo map (16% of the Lunar surface) at the resolution of 10 meters/pixel.

  2. Europa Stunning Surface

    NASA Image and Video Library

    2014-11-21

    The puzzling, fascinating surface of Jupiter icy moon Europa looms large in this newly-reprocessed [sic] color view, made from images taken by NASA Galileo spacecraft in the late 1990s. This is the color view of Europa from Galileo that shows the largest portion of the moon's surface at the highest resolution. The view was previously released as a mosaic with lower resolution and strongly enhanced color (see PIA02590). To create this new version, the images were assembled into a realistic color view of the surface that approximates how Europa would appear to the human eye. The scene shows the stunning diversity of Europa's surface geology. Long, linear cracks and ridges crisscross the surface, interrupted by regions of disrupted terrain where the surface ice crust has been broken up and re-frozen into new patterns. Color variations across the surface are associated with differences in geologic feature type and location. For example, areas that appear blue or white contain relatively pure water ice, while reddish and brownish areas include non-ice components in higher concentrations. The polar regions, visible at the left and right of this view, are noticeably bluer than the more equatorial latitudes, which look more white. This color variation is thought to be due to differences in ice grain size in the two locations. Images taken through near-infrared, green and violet filters have been combined to produce this view. The images have been corrected for light scattered outside of the image, to provide a color correction that is calibrated by wavelength. Gaps in the images have been filled with simulated color based on the color of nearby surface areas with similar terrain types. This global color view consists of images acquired by the Galileo Solid-State Imaging (SSI) experiment on the spacecraft's first and fourteenth orbits through the Jupiter system, in 1995 and 1998, respectively. Image scale is 1 mile (1.6 kilometers) per pixel. North on Europa is at right

  3. Quantitative Hydrocarbon Surface Analysis

    NASA Technical Reports Server (NTRS)

    Douglas, Vonnie M.

    2000-01-01

    The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.

  4. Ocular surface tumors

    PubMed Central

    Othman, Ihab Saad

    2009-01-01

    Tumors of the conjunctiva and cornea comprise a large and varied spectrum of conditions. These tumors are grouped into two major categories of congenital and acquired lesions. The acquired lesions are further subdivided based on origin of the mass into surface epithelial, mucoepidermoid, melanocytic, vascular, fibrous, neural, histiocytic, myxoid, myogenic, lipomatous, lymphoid, leukemic, metastatic and secondary tumors. Ocular surface tumors include a variety of neoplasms originating from squamous epithelium, melanocytic tumors and lymphocytic resident cells of the conjunctival stroma. In this review, we highlight clinical features of these lesions, important diagnostic and investigative tools and standard care of management. PMID:21234217

  5. A Thermochromic Superhydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Cataldi, Pietro; Bayer, Ilker S.; Cingolani, Roberto; Marras, Sergio; Chellali, Ryad; Athanassiou, Athanassia

    2016-06-01

    Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X-ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d-spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π-π interchain stacking in P3HT with uniform d-spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings.

  6. A Thermochromic Superhydrophobic Surface

    PubMed Central

    Cataldi, Pietro; Bayer, Ilker S.; Cingolani, Roberto; Marras, Sergio; Chellali, Ryad; Athanassiou, Athanassia

    2016-01-01

    Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X-ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d-spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π–π interchain stacking in P3HT with uniform d-spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings. PMID:27301422

  7. Surface Erosion and Flow

    NASA Image and Video Library

    2003-04-09

    The mottled surface texture and flow features observed in this NASA Mars Odyssey image suggest materials may be, or have been, mixed with ice. There is also evidence in some areas for infilling of sediments as crater rims and ridges appear covered.

  8. Planetary Surface Instruments Workshop

    NASA Technical Reports Server (NTRS)

    Meyer, Charles (Editor); Treiman, Allan H. (Editor); Kostiuk, Theodor (Editor)

    1996-01-01

    This report on planetary surface investigations and planetary landers covers: (1) the precise chemical analysis of solids; (2) isotopes and evolved gas analyses; (3) planetary interiors; planetary atmospheres from within as measured by landers; (4) mineralogical examination of extraterrestrial bodies; (5) regoliths; and (6) field geology/processes.

  9. Cratered Surface of Ceres

    NASA Image and Video Library

    2015-03-02

    The surface of Ceres is covered with craters of many shapes and sizes, as seen in this new mosaic of the dwarf planet comprised of images taken by NASA Dawn mission on Feb. 19, 2015 from a distance of nearly 29,000 miles 46,000 kilometers.

  10. Surface tension and microgravity

    NASA Astrophysics Data System (ADS)

    Meseguer, J.; Sanz-Andrés, A.; Pérez-Grande, I.; Pindado, S.; Franchini, S.; Alonso, G.

    2014-09-01

    The behaviour of confined liquids on board an orbiting spacecraft is mainly driven by surface tension phenomena, which cause an apparently anomalous response of the liquid when compared with the behaviour that can be observed on an Earth laboratory provided that the amount of liquid is high enough. The reason is that in an orbiting spacecraft the different inertial forces acting on the bulk of the liquid are almost zero, causing thus capillary forces to be the dominant ones. Of course, since gravity forces are proportional to the liquid volume, whereas surface tension forces are proportional to the liquid surface, there are situations on Earth where capillarity can be the dominant effect, as it happens when very small volume liquid samples are considered. However, work with small size samples may require the use of sophisticated optical devices. Leaving aside the neutral buoyancy technique, a way of handling large liquid interfaces is by using drop towers, where the sample falls subjected to the action of Earth’s gravity. This approach is suitable when the characteristic time of the problem under consideration is much smaller than the drop time. In this work the transformation of an out-of-use chimney into a drop tower is presented. Because of the miniaturization, hardiness and low cost of current electronic devices, a drop tower can be used as an inexpensive tool for undergraduate students to experimentally analyse a large variety of surface tension driven phenomena.

  11. Multiband frequency selective surface

    NASA Astrophysics Data System (ADS)

    Wu, Te-Kao

    1998-10-01

    This paper addresses the similarity of microwave/millimeter wave frequency selective surfaces (FSS) to optical filters. Specifically, the design approaches of the 4-band FSSs developed for NASA's CASSINI high gain antenna are described in detail. Representative RF test results are given to demonstrate the validity of these designs. These design approaches are very general and can be applied to multiband optical filters.

  12. Checking Surface Contours

    NASA Technical Reports Server (NTRS)

    Velega, D.

    1983-01-01

    Rubber impressions viewed with optical comparator. Simple mold constructed from aluminum sheet or any other easily shaped material compatible with silicone rubber ingredients. Mold placed over surface to be measured. Newly-mixed silicone rubber compound poured in mold and allowed to cure.

  13. Predictive Surface Complexation Modeling

    SciTech Connect

    Sverjensky, Dimitri A.

    2016-11-29

    Surface complexation plays an important role in the equilibria and kinetics of processes controlling the compositions of soilwaters and groundwaters, the fate of contaminants in groundwaters, and the subsurface storage of CO2 and nuclear waste. Over the last several decades, many dozens of individual experimental studies have addressed aspects of surface complexation that have contributed to an increased understanding of its role in natural systems. However, there has been no previous attempt to develop a model of surface complexation that can be used to link all the experimental studies in order to place them on a predictive basis. Overall, my research has successfully integrated the results of the work of many experimentalists published over several decades. For the first time in studies of the geochemistry of the mineral-water interface, a practical predictive capability for modeling has become available. The predictive correlations developed in my research now enable extrapolations of experimental studies to provide estimates of surface chemistry for systems not yet studied experimentally and for natural and anthropogenically perturbed systems.

  14. Decontaminating metal surfaces

    DOEpatents

    Childs, Everett L.

    1984-11-06

    Radioactively contaminated surfaces can be electrolytically decontaminated with greatly increased efficiencies by using electrolytes containing higher than heretofore conventional amounts of nitrate, e.g.,>600 g/l of NaNO.sub.3, or by using nitrate-containing electrolytes which are acidic, e.g., of a pH<6.

  15. Surface-Shading Program

    NASA Technical Reports Server (NTRS)

    Plessel, Todd

    1992-01-01

    Surface Shading program, SURF, developed to enable interactive input of grid and solution files from PLOT3D/AMES program; to use those files in interactive creation of wire-frame, shaded, and function-mapped images of parts to view; then to put out ARCGraph standard files animated by use of GAS (COSMIC Program ARC-12379). Written in C.

  16. Decontaminating metal surfaces

    DOEpatents

    Childs, E.L.

    1984-01-23

    Radioactively contaminated surfaces can be electrolytically decontaminated with greatly increased efficiencies by using electrolytes containing higher than heretofore conventional amounts of nitrate, e.g., >600 g/1 of NaNO/sub 3/, or by using nitrate-containing electrolytes which are acidic, e.g., of a pH < 6.

  17. Surface segregation during irradiation

    SciTech Connect

    Rehn, L.E.; Lam, N.Q.

    1985-10-01

    Gibbsian adsorption is known to alter the surface composition of many alloys. During irradiation, four additional processes that affect the near-surface alloy composition become operative: preferential sputtering, displacement mixing, radiation-enhanced diffusion and radiation-induced segregation. Because of the mutual competition of these five processes, near-surface compositional changes in an irradiation environment can be extremely complex. Although ion-beam induced surface compositional changes were noted as long as fifty years ago, it is only during the past several years that individual mechanisms have been clearly identified. In this paper, a simple physical description of each of the processes is given, and selected examples of recent important progress are discussed. With the notable exception of preferential sputtering, it is shown that a reasonable qualitative understanding of the relative contributions from the individual processes under various irradiation conditions has been attained. However, considerably more effort will be required before a quantitative, predictive capability can be achieved. 29 refs., 8 figs.

  18. Mercury Heavily Cratered Surface

    NASA Image and Video Library

    1999-10-07

    As NASA Mariner 10 approached Mercury at nearly seven miles per second on March 29, 1974, its TV camera took this picture from an altitude of 35,000 kilometers 21,700 miles The picture shows a heavily-cratered surface with many low hills

  19. Surface Electrochemistry of Metals

    DTIC Science & Technology

    1993-04-30

    171.** Auger Electron Angular Distributions from Underpotentially Deposited Ag Monolayers and Films at Pt(I 11) Pretreated with Iodine. Charles A...chemical vapor deposition (RTCVD), in which the heated Si(100) surface was carbonized with propane. Auger emission angular distributions were measured

  20. Effective Free Surfaces

    NASA Astrophysics Data System (ADS)

    Yapalparvi, Ramesh; Protas, Bartosz

    2010-11-01

    In this investigation we introduce the concept of an "effective free surface" arising as a solution of time--averaged equations in the presence of free boundaries. This work is motivated by applications of optimization theory to problems involving free surfaces, such as droplets impinging on the weld pool surface in welding processes. In such problems the time--dependent governing equations lead to technical difficulties, many of which are alleviated when methods of optimization are applied to a steady problem with effective free surfaces. The corresponding equations are obtained by performing the Reynolds decomposition and averaging of the time--dependent free--boundary equations based on the volume--of--fluid (VoF) formalism. We identify the terms representing the average effect of fluctuating free boundaries which, in analogy with the Reynolds stresses in classical turbulence models, need to be modelled and propose some simple algebraic closures for these terms. We argue that effective free boundaries can be computed using methods of shape optimization and present some results.

  1. Scraped surface heat exchangers.

    PubMed

    Rao, Chetan S; Hartel, Richard W

    2006-01-01

    Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

  2. Are Graphs Finally Surfacing?

    ERIC Educational Resources Information Center

    Beineke, Lowell W.

    1989-01-01

    Explored are various aspects of drawing graphs on surfaces. The Euler's formula, Kuratowski's theorem and the drawing of graphs in the plane with as few crossings as possible are discussed. Some applications including embedding of graphs and coloring of maps are included. (YP)

  3. Copernicus: Lunar surface mapper

    NASA Technical Reports Server (NTRS)

    Redd, Frank J.; Anderson, Shaun D.

    1992-01-01

    The Utah State University (USU) 1991-92 Space Systems Design Team has designed a Lunar Surface Mapper (LSM) to parallel the development of the NASA Office of Exploration lunar initiatives. USU students named the LSM 'Copernicus' after the 16th century Polish astronomer, for whom the large lunar crater on the face of the moon was also named. The top level requirements for the Copernicus LSM are to produce a digital map of the lunar surface with an overall resolution of 12 meters (39.4 ft). It will also identify specified local surface features/areas to be mapped at higher resolutions by follow-on missions. The mapping operation will be conducted from a 300 km (186 mi) lunar-polar orbit. Although the entire surface should be mapped within six months, the spacecraft design lifetime will exceed one year with sufficient propellant planned for orbit maintenance in the anomalous lunar gravity field. The Copernicus LSM is a small satellite capable of reaching lunar orbit following launch on a Conestoga launch vehicle which is capable of placing 410 kg (900 lb) into translunar orbit. Upon orbital insertion, the spacecraft will weigh approximately 233 kg (513 lb). This rather severe mass constraint has insured attention to component/subsystem size and mass, and prevented 'requirements creep.' Transmission of data will be via line-of-sight to an earth-based receiving system.

  4. Surface Chemistry Maps

    NASA Image and Video Library

    2015-03-13

    Maps of magnesium/silicon (left) and thermal neutron absorption (right) across Mercury's surface (red indicates high values, blue low) are shown. These maps, together with maps of other elemental abundances, reveal the presence of distinct geochemical terranes. Volcanic smooth plains deposits are outlined in white. Read the mission news story to learn more! http://photojournal.jpl.nasa.gov/catalog/PIA19242

  5. Laser surface cleaning

    SciTech Connect

    Freiwald, J.G.; Freiwald, D.A.

    1994-12-31

    The objective of this work is a laboratory demonstration that red-lead primer and two-part epoxy paints can be stripped from concrete and metal surfaces using surface cleaning systems based on pulsed-repetition CO{sub 2} lasers. The three goals are to: (1) demonstrate coatings removal, including surface pore cleaning; (2) demonstrate that there is negligible release of ablated contaminants to the environment; and (3) demonstrate that the process will generate negligible amounts of additional waste compared to competing technologies. Phase 1 involved site visits to RMI and Fernald to assess the cleaning issues for buildings and parts. In addition, Phase 1 included detailed designs of a more powerful system for industrial cleaning rates, including laser, articulating optics, ablated-material capture suction nozzle attached to a horizontal raster scanner for floor cleaning, and filtration system. Some concept development is also being done for using robots, and for parts cleaning. In Phase 2 a transportable 6 kW system will be built and tested, with a horizontal surface scanner for cleaning paint from floors. The laboratory tests will again be instrumented. Some concept development will continue for using robots, and for parts cleaning. This report describes Phase 1 results.

  6. Surface Traffic Management Research

    NASA Technical Reports Server (NTRS)

    Jung, Yoo Chul

    2012-01-01

    This presentation discusses an overview of the surface traffic management research conducted by NASA Ames. The concept and human-in-the-loop simulation of the Spot and Runway Departure Advisor (SARDA), an integrated decision support tool for the tower controllers and airline ramp operators, is also discussed.

  7. Advanced Surface Flux Parameterization

    DTIC Science & Technology

    2001-09-30

    within PE 0602435N are BE-35-2-18, for the Mesoscale Modeling of the Atmos- phere and Aerosols, BE-35-2-19, and for the Exploratory Data Assimilation ... Methods . Related project at NPS is N0001401WR20242 for Evaluating Surface Flux and Boundary Layer Parameterizations in Mesoscale Models Using

  8. Surface Radiation Budget

    NASA Technical Reports Server (NTRS)

    Stackhouse, Paul W. (Principal Investigator)

    The Surface Radiation Budget (SRB) data sets contain global 3-hourly, daily and monthly averages of surface longwave and shortwave radiative properties, cloud amount, and meteorological properties computed using models. The main input data for these models include cloud information, top-of-atmosphere radiances and profiles of atmospheric water vapor and temperature. Some of the input data include Earth Radiation Budget Energy (ERBE) top-of-atmosphere clear-sky albedo and International Satellite Cloud Climatology Project (ISCCP) radiances and cloud amount. SRB parameters derived for the renewable energy community are also available from the Surface meteorology and Solar Energy (SSE) data set. Other SRB data are available from Clouds and the Earth's Radiant Energy System (CERES) and Multi-angle Imaging SpectroRadiometer (MISR). [Mission Objectives] The objective of the SRB Project is to produce and archive a global data set of shortwave (SW) and longwave (LW) surface and top of the atmosphere parameters. The data generated in the SRB project may be used in conjunction with other data sets to facilitate the development of renewable energy resources and increase understanding of radiative properties within the meteorological community. [Temporal_Coverage: Start_Date=1983-07-01; Stop_Date=2005-06-30] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180].

  9. A Thermochromic Superhydrophobic Surface.

    PubMed

    Cataldi, Pietro; Bayer, Ilker S; Cingolani, Roberto; Marras, Sergio; Chellali, Ryad; Athanassiou, Athanassia

    2016-06-15

    Highly enhanced solid-state thermochromism is observed in regioregular poly(3-hexylthiophene), P3HT, when deposited on a superhydrophobic polymer-SiO2 nanocomposite coating. The conformal P3HT coating on the nanocomposite surface does not alter or reduce superhydrophicity while maintaining its reversible enhanced thermochromism. The polymeric matrix of the superhydrophobic surface is comprised of a blend of poly(vinylidene fluoride-co-hexafluoropropylene) copolymer and an acrylic adhesive. Based on detailed X-ray diffraction measurements, this long-lasting, repeatable and hysteresis-free thermochromic effect is attributed to the enhancement of the Bragg peak associated with the d-spacing of interchain directional packing (100) which remains unaltered during several heating-cooling cycles. We propose that the superhydrophobic surface confines π-π interchain stacking in P3HT with uniform d-spacing into its nanostructured texture resulting in better packing and reduction in face-on orientation. The rapid response of the system to sudden temperature changes is also demonstrated by water droplet impact and bounce back on heated surfaces. This effect can be exploited for embedded thin film temperature sensors for metal coatings.

  10. Experiments with Planing Surfaces

    NASA Technical Reports Server (NTRS)

    Sottorf, W

    1934-01-01

    A previous report discusses the experimental program of a systematic exploration of all questions connected with the planing problem as well as the first fundamental results of the investigation of a flat planing surface. The present report is limited to the conversion of the model test data to full scale.

  11. Titan's surface and atmosphere

    NASA Astrophysics Data System (ADS)

    Hayes, Alexander G.; Soderblom, Jason M.; Ádámkovics, Máté

    2016-05-01

    Since its arrival in late 2004, the NASA/ESA Cassini-Huygens mission to Saturn has revealed Titan to be a world that is both strange and familiar. Titan is the only extraterrestrial body known to support standing bodies of stable liquid on its surface and, along with Earth and early Mars, is one of three places in the Solar System known to have had an active hydrologic cycle. With atmospheric pressures of 1.5 bar and temperatures of 90-95 K at the surface, methane and ethane condense out of Titan's nitrogen-dominated atmosphere and flow as liquids on the surface. Despite vast differences in environmental conditions and materials from Earth, Titan's methane-based hydrologic cycle drives climatic and geologic processes which generate landforms that are strikingly similar to their terrestrial counterparts, including vast equatorial dunes, well-organized channel networks that route material through erosional and depositional landscapes, and lakes and seas of liquid hydrocarbons. These similarities make Titan a natural laboratory for studying the processes that shape terrestrial landscapes and drive climates, probing extreme conditions impossible to recreate in earthbound laboratories. Titan's exotic environment ensures that even rudimentary measurements of atmospheric/surface interactions, such as wind-wave generation or aeolian dune development, provide valuable data to anchor physical models.

  12. Surface Mesohighs and Mesolows.

    NASA Astrophysics Data System (ADS)

    Johnson, Richard H.

    2001-01-01

    Through detailed and remarkably insightful analyses of surface data, Tetsuya Theodore Fujita pioneered modern mesoanalysis, unraveling many of the mysteries of severe storms. In this paper Fujita's contributions to the analysis and description of surface pressure features accompanying tornadic storms and squall lines are reviewed.On the scale of individual thunderstorm cells Fujita identified pressure couplets: a mesolow associated with the tornado cyclone and a mesohigh in the adjacent heavy precipitation area to the north. On larger scales, he found that squall lines contain mesohighs associated with the convective line and wake depressions (now generally called wake lows) to the rear of storms. Fujita documented the structure and life cycles of these phenomena using time-to-space conversion of barograph data.Subsequent investigations have borne out many of Fujita's findings of nearly 50 years ago. His analyses of the surface pressure field accompanying tornadic supercells have been validated by later studies, in part because of the advent of mobile mesonetworks. The analyses of squall-line mesohighs and wake lows have been confirmed and extended, particularly by advances in radar observations. These surface pressure features appear to be linked to processes both in the convective line and attendant stratiform precipitation regions, as well as to rear-inflow jets, gravity currents, and gravity waves, but specific roles of each of these phenomena in the formation of mesohighs and wake lows have yet to be fully resolved.

  13. Surface Analysis and Tools

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2002-01-01

    This article is a chapter of the book entitled, "Tribology of Mechanical Systems," to be published by ASME Press, New York, NY. It describes selected analytical techniques, which are being used in understanding phenomena and mechanisms of oxidation, adhesion, bonding, friction, erosion, abrasion, and wear, and in defining the problems. The primary emphasis is on microanalytical approaches to engineering surfaces.

  14. Surface complexation modeling

    USDA-ARS?s Scientific Manuscript database

    Adsorption-desorption reactions are important processes that affect the transport of contaminants in the environment. Surface complexation models are chemical models that can account for the effects of variable chemical conditions, such as pH, on adsorption reactions. These models define specific ...

  15. Surface Water in Hawaii

    USGS Publications Warehouse

    Oki, Delwyn S.

    2003-01-01

    Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

  16. Computer aided surface representation

    SciTech Connect

    Barnhill, R.E.

    1991-04-02

    Modern computing resources permit the generation of large amounts of numerical data. These large data sets, if left in numerical form, can be overwhelming. Such large data sets are usually discrete points from some underlying physical phenomenon. Because we need to evaluate the phenomenon at places where we don't have data, a continuous representation (a surface'') is required. A simple example is a weather map obtained from a discrete set of weather stations. (For more examples including multi-dimensional ones, see the article by Dr. Rosemary Chang in the enclosed IRIS Universe). In order to create a scientific structure encompassing the data, we construct an interpolating mathematical surface which can evaluate at arbitrary locations. We can also display and analyze the results via interactive computer graphics. In our research we construct a very wide variety of surfaces for applied geometry problems that have sound theoretical foundations. However, our surfaces have the distinguishing feature that they are constructed to solve short or long term practical problems. This DOE-funded project has developed the premiere research team in the subject of constructing surfaces (3D and higher dimensional) that provide smooth representations of real scientific and engineering information, including state of the art computer graphics visualizations. However, our main contribution is in the development of fundamental constructive mathematical methods and visualization techniques which can be incorporated into a wide variety of applications. This project combines constructive mathematics, algorithms, and computer graphics, all applied to real problems. The project is a unique resource, considered by our peers to be a de facto national center for this type of research.

  17. On the temperature of surfaces

    NASA Technical Reports Server (NTRS)

    Mann, J. Adin, Jr.; Edwards, Robert V.

    1989-01-01

    The concept of the temperature of a surface is introduced from the viewpoint of the physical chemistry of surfaces. The surface, near surface and microlayer regions of the interface are defined. Most methods measure the temperature of the microlayer or at best the near surface region and may err in representing the surface temperature. Methods based on capillary ripples actually measure the surface temperature since surface tension (or surface tension tensor when a monolayer has been spread or absorbed at the interface) is the main restoring force that controls their propagation. Light scattering methods are described for determining the elevation of very small amplitude capillary waves through the computation of various correlation functions from which the surface tension can be estimated. Procedures for estimating the surface temperature are described.

  18. In-surface confinement of topological insulator nanowire surface states

    SciTech Connect

    Chen, Fan W.; Jauregui, Luis A.; Tan, Yaohua; Manfra, Michael; Klimeck, Gerhard; Chen, Yong P.; Kubis, Tillmann

    2015-09-21

    The bandstructures of [110] and [001] Bi{sub 2}Te{sub 3} nanowires are solved with the atomistic 20 band tight binding functionality of NEMO5. The theoretical results reveal: The popular assumption that all topological insulator (TI) wire surfaces are equivalent is inappropriate. The Fermi velocity of chemically distinct wire surfaces differs significantly which creates an effective in-surface confinement potential. As a result, topological insulator surface states prefer specific surfaces. Therefore, experiments have to be designed carefully not to probe surfaces unfavorable to the surface states (low density of states) and thereby be insensitive to the TI-effects.

  19. Surface-enhanced spectroscopy

    NASA Astrophysics Data System (ADS)

    Moskovits, Martin

    1985-07-01

    In 1978 it was discovered, largely through the work of Fleischmann, Van Duyne, Creighton, and their coworkers that molecules adsorbed on specially prepared silver surfaces produce a Raman spectrum that is at times a millionfold more intense than expected. This effect was dubbed surface-enhanced Raman scattering (SERS). Since then the effect has been demonstrated with many molecules and with a number of metals, including Cu, Ag, Au, Li, Na, K, In, Pt, and Rh. In addition, related phenomena such as surface-enhanced second-harmonic generation, four-wave mixing, absorption, and fluorescence have been observed. Although not all fine points of the enhancement mechanism have been clarified, the majority view is that the largest contributor to the intensity amplification results from the electric field enhancement that occurs in the vicinity of small, interacting metal particles that are illuminated with light resonant or near resonant with the localized surface-plasmon frequency of the metal structure. Small in this context is gauged in relation to the wavelength of light. The special preparations required to produce the effect, which include among other techniques electrochemical oxidation-reduction cycling, deposition of metal on very cold substrates, and the generation of metal-island films and colloids, is now understood to be necessary as a means of producing surfaces with appropriate electromagnetic resonances that may couple to electromagnetic fields either by generating rough films (as in the case of the former two examples) or by placing small metal particles in close proximity to one another (as in the case of the latter two). For molecules chemisorbed on SERS-active surface there exists a "chemical enhancement" in addition to the electromagnetic effect. Although difficult to measure accurately, the magnitude of this effect rarely exceeds a factor of 10 and is best thought to arise from the modification of the Raman polarizability tensor of the adsorbate

  20. Smart, passive sun facing surfaces

    DOEpatents

    Hively, L.M.

    1996-04-30

    An article adapted for selectively utilizing solar radiation comprises an absorptive surface and a reflective surface, the absorptive surface and the reflective surface oriented to absorb solar radiation when the sun is in a relatively low position, and to reflect solar radiation when the sun is in a relatively high position. 17 figs.

  1. Smart, passive sun facing surfaces

    DOEpatents

    Hively, Lee M.

    1996-01-01

    An article adapted for selectively utilizing solar radiation comprises an absorptive surface and a reflective surface, the absorptive surface and the reflective surface oriented to absorb solar radiation when the sun is in a relatively low position, and to reflect solar radiation when the sun is in a relatively high position.

  2. Surface decontamination compositions and methods

    DOEpatents

    Wright,; Karen, E [Idaho Falls, ID; Cooper, David C [Idaho Falls, ID; Peterman, Dean R [Idaho Falls, ID; Demmer, Ricky L [Idaho Falls, ID; Tripp, Julia L [Pocatello, ID; Hull, Laurence C [Idaho Falls, ID

    2011-03-29

    Clay-based compositions capable of absorbing contaminants from surfaces or objects having surface faces may be applied to a surface and later removed, the removed clay-based compositions absorbing at least a portion of the contaminant from the surface or object to which it was applied.

  3. Surface Enhanced Quantum Control

    NASA Astrophysics Data System (ADS)

    Rangan, Chitra

    2013-05-01

    Miniaturization of quantum technologies have led to physics that require the marriage of atomic physics and nanomaterials science. Some of the resulting areas of research are hybrid quantum devices, single-molecule spectroscopies, table-top intense field generators, etc. I will present an area of research that I dub ``Surface-enhanced quantum control'' that is an exciting way of controlling light and nanomatter. By combining the electromagnetic enhancement properties of plasmonic nanomaterials with the modification of the atomic properties, we can achieve an unprecedented level of control over quantum dynamics. I will present examples of surface-enhanced state purification, in which quantum states near metal nanostructures can be rapidly purified by the application of a weak near-resonant control field. We gratefully acknowledge support from the NSERC Discovery Grant Program and the NSERC Strategic Network for Bioplasmonic Systems.

  4. Integrated Airport Surface Operations

    NASA Technical Reports Server (NTRS)

    Koczo, S.

    1998-01-01

    The current air traffic environment in airport terminal areas experiences substantial delays when weather conditions deteriorate to Instrument Meteorological Conditions (IMC). Research activity at NASA has culminated in the development, flight test and demonstration of a prototype Low Visibility Landing and Surface Operations (LVLASO) system. A NASA led industry team and the FAA developed the system which integrated airport surface surveillance systems, aeronautical data links, DGPS navigation, automation systems, and controller and flight deck displays. The LVLASO system was demonstrated at the Hartsfield-Atlanta International Airport using a Boeing 757-200 aircraft during August, 1997. This report documents the contractors role in this testing particularly in the area of data link and DGPS navigation.

  5. Automated airplane surface generation

    SciTech Connect

    Smith, R.E.; Cordero, Y.; Jones, W.

    1996-12-31

    An efficient methodology and software axe presented for defining a class of airplane configurations. A small set of engineering design parameters and grid control parameters govern the process. The general airplane configuration has wing, fuselage, vertical tall, horizontal tail, and canard components. Wing, canard, and tail surface grids axe manifested by solving a fourth-order partial differential equation subject to Dirichlet and Neumann boundary conditions. The design variables are incorporated into the boundary conditions, and the solution is expressed as a Fourier series. The fuselage is described by an algebraic function with four design parameters. The computed surface grids are suitable for a wide range of Computational Fluid Dynamics simulation and configuration optimizations. Both batch and interactive software are discussed for applying the methodology.

  6. Antibacterial Metallic Touch Surfaces

    PubMed Central

    Villapún, Victor M.; Dover, Lynn G.; Cross, Andrew; González, Sergio

    2016-01-01

    Our aim is to present a comprehensive review of the development of modern antibacterial metallic materials as touch surfaces in healthcare settings. Initially we compare Japanese, European and US standards for the assessment of antimicrobial activity. The variations in methodologies defined in these standards are highlighted. Our review will also cover the most relevant factors that define the antimicrobial performance of metals, namely, the effect of humidity, material geometry, chemistry, physical properties and oxidation of the material. The state of the art in contact-killing materials will be described. Finally, the effect of cleaning products, including disinfectants, on the antimicrobial performance, either by direct contact or by altering the touch surface chemistry on which the microbes attach, will be discussed. We offer our outlook, identifying research areas that require further development and an overview of potential future directions of this exciting field. PMID:28773856

  7. Measurement of surface microtopography

    NASA Technical Reports Server (NTRS)

    Wall, S. D.; Farr, T. G.; Muller, J.-P.; Lewis, P.; Leberl, F. W.

    1991-01-01

    Acquisition of ground truth data for use in microwave interaction modeling requires measurement of surface roughness sampled at intervals comparable to a fraction of the microwave wavelength and extensive enough to adequately represent the statistics of a surface unit. Sub-centimetric measurement accuracy is thus required over large areas, and existing techniques are usually inadequate. A technique is discussed for acquiring the necessary photogrammetric data using twin film cameras mounted on a helicopter. In an attempt to eliminate tedious data reduction, an automated technique was applied to the helicopter photographs, and results were compared to those produced by conventional stereogrammetry. Derived root-mean-square (RMS) roughness for the same stereo-pair was 7.5 cm for the automated technique versus 6.5 cm for the manual method. The principal source of error is probably due to vegetation in the scene, which affects the automated technique but is ignored by a human operator.

  8. Pocked surface neutron detector

    DOEpatents

    McGregor, Douglas; Klann, Raymond

    2003-04-08

    The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

  9. Ion beam surface modification

    NASA Technical Reports Server (NTRS)

    Dwight, D. W.

    1982-01-01

    The essential details of a study on the practical applications and mechanisms of polymer sputtering via Argon ion impact are summarized. The potential to modify the properties of polymer surfaces to improve their adherence, durability, biocompatibility, or other desirable properties by ion beam sputtering was emphasized. Ion beam milling can be of benefit as an analytical tool to obtain composition versus depth information. Ion impact from a directed ion gun source specifically etches polymer structures according to their morphologies, therefore this technique may be useful to study unknown or new morphological features. Factors addressed were related to: (1) the texture that arises on a polymer target after ion impact; (2) the chemistry of the top surface after ion impact; (3) the chemistry of sputtered films of polymeric material deposited on substrates placed adjacent to targets during ion impact; and (4) practical properties of textured polymer targets, specifically the wettability and adhesive bonding properties.

  10. Remote surface inspection system

    NASA Technical Reports Server (NTRS)

    Hayati, S.; Balaram, J.; Seraji, H.; Kim, W. S.; Tso, K.; Prasad, V.

    1993-01-01

    This paper reports on an on-going research and development effort in remote surface inspection of space platforms such as the Space Station Freedom (SSF). It describes the space environment and identifies the types of damage for which to search. This paper provides an overview of the Remote Surface Inspection System that was developed to conduct proof-of-concept demonstrations and to perform experiments in a laboratory environment. Specifically, the paper describes three technology areas: (1) manipulator control for sensor placement; (2) automated non-contact inspection to detect and classify flaws; and (3) an operator interface to command the system interactively and receive raw or processed sensor data. Initial findings for the automated and human visual inspection tests are reported.

  11. Surface recombination in semiconductors

    SciTech Connect

    Langer, J.M.; Walukiewicz, W.

    1995-07-01

    We propose two general criteria for a surface defect state to act as an efficient, nonradiative recombination center. The first is that the thermal ionization energy should not deviate from the mid-gap energy by more than the relaxation energy of the defect, In this case the activation energy for the recombination is given by the barrier for the capture of the first carrier, whereas the second carrier is captured athermally. The second citerion is related to the position of the average dangling bond energy relative to the band edges. If, as in the cases of InP or InAs, it is located close to a band edge, a low surface recombination velocity is expected. However a much faster recombination is predicated and experimentally observed in the materials with the average dangling bond energy located close to the mid-gap. The relevance of these criteria for the novel wide-gap optoelectronic materials is discussed.

  12. Resolving stellar surface spots

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Carroll, T.; Rice, J. B.; Savanov, I. S.

    Doppler imaging of stellar surfaces is a novel technique with similarities to medical brain tomography (instead of a fixed brain and a rotating scanner, astronomers have a fixed spectrograph and a rotating brain, star of course). The number of free (internal) parameters is of the order of the number of surface grid points and only constrained by the number of input data points. This obviously ill-posed situation requires modern inversion algorithms with penalty functions of the form of maximum entropy or Tikhonov etc.. We present a brief status review of our Doppler imaging codes at AIP that span from temperature and spot-filling-factor mapping to full Stokes-based magnetic field mapping.

  13. Discrete Minimal Surface Algebras

    NASA Astrophysics Data System (ADS)

    Arnlind, Joakim; Hoppe, Jens

    2010-05-01

    We consider discrete minimal surface algebras (DMSA) as generalized noncommutative analogues of minimal surfaces in higher dimensional spheres. These algebras appear naturally in membrane theory, where sequences of their representations are used as a regularization. After showing that the defining relations of the algebra are consistent, and that one can compute a basis of the enveloping algebra, we give several explicit examples of DMSAs in terms of subsets of sln (any semi-simple Lie algebra providing a trivial example by itself). A special class of DMSAs are Yang-Mills algebras. The representation graph is introduced to study representations of DMSAs of dimension d ≤ 4, and properties of representations are related to properties of graphs. The representation graph of a tensor product is (generically) the Cartesian product of the corresponding graphs. We provide explicit examples of irreducible representations and, for coinciding eigenvalues, classify all the unitary representations of the corresponding algebras.

  14. Martian surface weathering studies

    NASA Technical Reports Server (NTRS)

    Calvin, M.

    1973-01-01

    The nature of the Martian surface was characterized by means of its reflectance properties. The Mariner 9 photography was used to establish terrain units which were crossed by the Mariner 6 and 7 paths. The IR reflectance measured by the IR spectrometers on these spacecraft was to be used to indicate the nature of the surface within these units. There is an indication of physical size and/or compositional variation between units but too many natural parameters can vary (size, shape, composition, adsorbed phases, reradiation, atmospheric absorbtion, temperature gradients, etc.) to be certain what effect is causing those variations observed. It is suggested that the characterization could be fruitfully pursued by a group which was dedicated to peeling back the layers of minutia affecting IR reflectance.

  15. Surface modifications of nitinol.

    PubMed

    Haider, Waseem; Munroe, N; Tek, V; Pulletikurthi, C; Gill, P K S; Pandya, S

    2009-01-01

    Nitinol (an acronym for the Nickel-Titanium Naval Ordnance Laboratory) has been extensively explored as an implant material for the medical industry. The potential problem with Nitinol implant devices is the release of Ni in the human body, which has stimulated a great deal of research on surface modifications and the application of coatings. This paper presents a comprehensive review of various treatments to modify the surface of Nitinol in an effort to inhibit Ni release and to render improved biocompatibility. We discuss the important in-service properties of Nitinol, such as biocompatibility, corrosion resistance, stability, uniformity, and the nature of passivating oxides produced by passivation, electropolishing, magnetoelectropolishing, ion beam implantation, sterilization, and artificial coatings.

  16. Parametric surface denoising

    NASA Astrophysics Data System (ADS)

    Kakadiaris, Ioannis A.; Konstantinidis, Ioannis; Papadakis, Manos; Ding, Wei; Shen, Lixin

    2005-08-01

    Three dimensional (3D) surfaces can be sampled parametrically in the form of range image data. Smoothing/denoising of such raw data is usually accomplished by adapting techniques developed for intensity image processing, since both range and intensity images comprise parametrically sampled geometry and appearance measurements, respectively. We present a transform-based algorithm for surface denoising, motivated by our previous work on intensity image denoising, which utilizes a non-separable Parseval frame and an ensemble thresholding scheme. The frame is constructed from separable (tensor) products of a piecewise linear spline tight frame and incorporates the weighted average operator and the Sobel operators in directions that are integer multiples of 45°. We compare the performance of this algorithm with other transform-based methods from the recent literature. Our results indicate that such transform methods are suited to the task of smoothing range images.

  17. Cryptosporidiosis and surface water.

    PubMed Central

    Gallaher, M M; Herndon, J L; Nims, L J; Sterling, C R; Grabowski, D J; Hull, H F

    1989-01-01

    In the period July through October, 1986, 78 laboratory-confirmed cases of cryptosporidiosis were identified in New Mexico. To determine possible risk factors for development of this disease, we conducted a case-control study; 24 case-patients and 46 neighborhood controls were interviewed. Seventeen (71 per cent) of the 24 case-patients were females, seven (29%) were males; their ages ranged from 4 months to 44 years, median 3 years. There was a strong association between drinking surface water and illness: five of the 24 case-patients, but none of the 46 controls drank untreated surface water. Among children, illness was also associated with attending a day care center where other children were ill (odds ratio = 13.1). PMID:2909180

  18. Surface Mediated Photocatalysis.

    DTIC Science & Technology

    1987-12-01

    tungsten atoms were compared in photocatalytic ability to semiconductor powders and single crystals of tungsten oxide . Evidence requiring...precomplexation of organic substrates for effective photoinduced oxidation was obtained, and a striking variation in photocatalytic activity was observed as the...Photosynthetic Reactions on Semiconductor Surfaces," M.A. Fox, New York Academy of Sciences, New York City, NY, November 1987. 4. " Photocatalytic Oxidation of

  19. Cryogenic Selective Surfaces

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert; Nurge, Mark

    2015-01-01

    Under our NASA Innovative Advanced Concepts (NIAC) project we have theoretically demonstrated a novel selective surface that reflects roughly 100 times more solar radiation than any other known coating. If this prediction holds up under experimental tests it will allow cryogenic temperatures to be reached in deep space even in the presence of the sun. It may allow LOX to be carried to the Moon and Mars. It may allow superconductors to be used in deep space without a refrigeration system.

  20. Riemann surface and quantization

    NASA Astrophysics Data System (ADS)

    Perepelkin, E. E.; Sadovnikov, B. I.; Inozemtseva, N. G.

    2017-01-01

    This paper proposes an approach of the unified consideration of classical and quantum mechanics from the standpoint of the complex analysis effects. It turns out that quantization can be interpreted in terms of the Riemann surface corresponding to the multivalent LnΨ function. A visual interpretation of "trajectories" of the quantum system and of the Feynman's path integral is presented. A magnetic dipole having a magnetic charge that satisfies the Dirac quantization rule was obtained.

  1. Charon's Surface in Detail

    NASA Image and Video Library

    2017-07-14

    On July 14, 2015, NASA's New Horizons spacecraft made its historic flight through the Pluto system. This detailed, high-quality global mosaic of Pluto's largest moon, Charon, was assembled from nearly all of the highest-resolution images obtained by the Long-Range Reconnaissance Imager (LORRI) and the Multispectral Visible Imaging Camera (MVIC) on New Horizons. The mosaic is the most detailed and comprehensive global view yet of Charon's surface using New Horizons data. It includes topography data of the hemisphere visible to New Horizons during the spacecraft's closest approach. The topography is derived from digital stereo-image mapping tools that measure the parallax -- or the difference in the apparent relative positions -- of features on the surface obtained at different viewing angles during the encounter. Scientists use these parallax displacements of high and low terrain to estimate landform heights. The global mosaic has been overlain with transparent, colorized topography data wherever on the surface stereo data is available. Terrain south of about 30°S was in darkness leading up to and during the flyby, so is shown in black. All feature names on Pluto and Charon are informal. The global mosaic has been overlain with transparent, colorized topography data wherever on their surfaces stereo data is available. Standing out on Charon is the Caleuche Chasma ("C") in the far north, an enormous trough at least 350 kilometers (nearly 220 miles) long, and reaching 14 kilometers (8.5 miles) deep -- more than seven times as deep as the Grand Canyon. https://photojournal.jpl.nasa.gov/catalog/PIA21860

  2. Applied Surface Analysis Workshop.

    DTIC Science & Technology

    1979-10-01

    field of surface analysis attended the Workshop. The list of participants follows. 5! A, I Charles Anderson Albert L. Botkin Case Western Reserve...Louis, MO 63166 University of Dayton 300 College Park Richard Chase Dayton, OH 45469 Case Western Reserve University University Circle Brian E. P...Dayton, OH 45469 300 College Park Dayton, OH 45469 Richard W. Hoffman Case Western Reserve University Martin Kordesch Cleveland, OH 44106 Case Western

  3. High Temperature Surface Interactions

    DTIC Science & Technology

    1989-11-01

    yttrium sulfide. Surface segregation studies were conducted employing Auger Electron Spectroscopy (AES) coupled with cyclic oxidation experiments...temperature (530*C) in air. The early stages of oxidation were studied by Auger electron spectroscopy (AES) with depth profiling using inert gas ion...basicity at 927 ’C are shown in Figure 7 . The purpose of such studies is to mfnlmize hot corrosion reactions by selection of an alloy or coating which is

  4. Deflation of elastic surfaces

    NASA Astrophysics Data System (ADS)

    Quilliet, Catherine; Quemeneur, François; Marmottant, Philippe; Imhof, Arnout; Pépin-Donat, Brigitte; van Blaaderen, Alfons

    2010-03-01

    The deflation of elastic spherical surfaces has been numerically investigated, and show very different types of deformations according the range of elastic parameters, some of them being quantitatively explained through simple calculations. This allows to retrieve various shapes observed on hollow shells (from colloidal to centimeter scale), on lipid vesicles, or on some biological objects. The extension of this process to other geometries allows to modelize vegetal objects such as the ultrafast trap of carnivorous plants.

  5. Planetary Surface Instruments Workshop

    NASA Astrophysics Data System (ADS)

    Meyer, Charles; Treiman, Allanh; Kostiuk, Theodor,

    1996-01-01

    This report on planetary surface investigations an d planetary landers covers: (1) the precise chemic al analysis of solids; (2) isotopes and evolved ga s analyses; (3) planetary interiors; planetary atm ospheres from within as measured by landers; (4) m ineralogical examination of extraterrestrial bodie s; (5) regoliths; and (6) field geology/processes . For individual titles, see N96-34812 through N96-34819. (Derived from text.)

  6. Surface Roughness Impedance

    SciTech Connect

    Stupakov, Gennady

    2000-12-21

    The next generation of linac-based free electron lasers will use very short bunches with a large peak current. For such beams, the impedance caused by submicron imperfections in the vacuum beam tube may generate an additional energy spread within the bunch. A review of two mechanisms of the roughness impedance is given with the emphasis on the importance of the high-aspect ratio property of the real surface roughness.

  7. Martian Surface & Pathfinder Airbags

    NASA Image and Video Library

    1997-07-05

    This image of the Martian surface was taken in the afternoon of Mars Pathfinder's first day on Mars. Taken by the Imager for Mars Pathfinder (IMP camera), the image shows a diversity of rocks strewn in the foreground. A hill is visible in the distance (the notch within the hill is an image artifact). Airbags are seen at the lower right. http://photojournal.jpl.nasa.gov/catalog/PIA00612

  8. Surface processes on Venus

    NASA Technical Reports Server (NTRS)

    Arvidson, R. E.

    1992-01-01

    Magellan synthetic aperture radar (SAR) and altimetry data were analyzed to determine the nature and extent of surface modification for venusian plains in the Sedna Planitia, Alpha Regio, and western Ovda Regio areas. Specific cross sections derived from the SAR data were also compared to similar data for dry terrestrial basaltic lava flows (Lunar Crater and Cima volcanic fields) and playas (Lunar and Lavic Lakes) for which microtopographic profiles (i.e., quantitative roughness information) were available.

  9. Surface temperature measurement errors

    SciTech Connect

    Keltner, N.R.; Beck, J.V.

    1983-05-01

    Mathematical models are developed for the response of surface mounted thermocouples on a thick wall. These models account for the significant causes of errors in both the transient and steady-state response to changes in the wall temperature. In many cases, closed form analytical expressions are given for the response. The cases for which analytical expressions are not obtained can be easily evaluated on a programmable calculator or a small computer.

  10. Laboratory surface astrochemistry experiments

    NASA Astrophysics Data System (ADS)

    Frankland, V. L.; Rosu-Finsen, A.; Lasne, J.; Collings, M. P.; McCoustra, M. R. S.

    2015-05-01

    Although several research groups have studied the formation of H2 on interstellar dust grains using surface science techniques, few have explored the formation of more complex molecules. A small number of these reactions produce molecules that remain on the surface of interstellar dust grains and, over time, lead to the formation of icy mantles. The most abundant of these species within the ice is H2O and is of particular interest as the observed molecular abundance cannot be accounted for using gas-phase chemistry alone. This article provides a brief introduction to the astronomical implications and motivations behind this research and the requirement for a new dual atomic beam ultrahigh vacuum (UHV) system. Further details of the apparatus design, characterisation, and calibration of the system are provided along with preliminary data from atomic O and O2 beam dosing on bare silica substrate and subsequent temperature programmed desorption measurements. The results obtained in this ongoing research may enable more chemically accurate surface formation mechanisms to be deduced for this and other species before simulating the kinetic data under interstellar conditions.

  11. Magnetometer on Lunar Surface

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Sitting on the lunar surface, this magnetometer provided new data on the Moon's magnetic field. This was one of the instruments used during the Apollo 12 mission. The second manned lunar landing mission, Apollo 12 launched from launch pad 39-A at Kennedy Space Center in Florida on November 14, 1969 via a Saturn V launch vehicle. The Saturn V vehicle was developed by the Marshall Space Flight Center (MSFC) under the direction of Dr. Wernher von Braun. Aboard Apollo 12 was a crew of three astronauts: Alan L. Bean, pilot of the Lunar Module (LM), Intrepid; Richard Gordon, pilot of the Command Module (CM), Yankee Clipper; and Spacecraft Commander Charles Conrad. The LM, Intrepid, landed astronauts Conrad and Bean on the lunar surface in what's known as the Ocean of Storms while astronaut Richard Gordon piloted the CM, Yankee Clipper, in a parking orbit around the Moon. Lunar soil activities included the deployment of the Apollo Lunar Surface Experiments Package (ALSEP), finding the unmanned Surveyor 3 that landed on the Moon on April 19, 1967, and collecting 75 pounds (34 kilograms) of rock samples. Apollo 12 safely returned to Earth on November 24, 1969.

  12. Antifungal nanoparticles and surfaces.

    PubMed

    Paulo, Cristiana S O; Vidal, Maria; Ferreira, Lino S

    2010-10-11

    Nosocomial fungal infections, an increasing healthcare concern worldwide, are often associated with medical devices. We have developed antifungal nanoparticle conjugates that can act in suspension or attach to a surface, efficiently killing fungi. For that purpose, we immobilized covalently amphotericin B (AmB), a potent antifungal agent approved by the FDA, widely used in clinical practice and effective against a large spectrum of fungi, into silica nanoparticles. These antifungal nanoparticle conjugates are fungicidal against several strains of Candida sp., mainly by contact. In addition, they can be reused up to 5 cycles without losing their activity. Our results show that the antifungal nanoparticle conjugates are more fungistatic and fungicidal than 10 nm colloidal silver. The antifungal activity of the antifungal nanoparticle conjugates is maintained when they are immobilized on a surface using a chemical adhesive formed by polydopamine. The antifungal nanocoatings have no hemolytic or cytotoxic effect against red blood cells and blood mononuclear cells, respectively. Surfaces coated with these antifungal nanoparticle conjugates can be very useful to render medical devices with antifungal properties.

  13. Surface profiling interferometer

    DOEpatents

    Takacs, Peter Z.; Qian, Shi-Nan

    1989-01-01

    The design of a long-trace surface profiler for the non-contact measurement of surface profile, slope error and curvature on cylindrical synchrotron radiation (SR) mirrors. The optical system is based upon the concept of a pencil-beam interferometer with an inherent large depth-of-field. The key feature of the optical system is the zero-path-difference beam splitter, which separates the laser beam into two colinear, variable-separation probe beams. A linear array detector is used to record the interference fringe in the image, and analysis of the fringe location as a function of scan position allows one to reconstruct the surface profile. The optical head is mounted on an air bearing slide with the capability to measure long aspheric optics, typical of those encountered in SR applications. A novel feature of the optical system is the use of a transverse "outrigger" beam which provides information on the relative alignment of the scan axis to the cylinder optic symmetry axis.

  14. Single Crystal Surfaces

    NASA Astrophysics Data System (ADS)

    Aguilar-Santillan, Joaquin

    2014-06-01

    The present work studies (0001) Al2O3 and (111) Al2MgO4 wetting with pure molten Al by the sessile drop technique from 1073 K to 1473 K (800 °C to 1200 °C) under Ar at PO2 10-15 Pa. Al pure liquid wets a smooth and chemically homogeneous surface of an inert solid, the wetting driving force ( t, T) can be readily studied when surface solid roughness increases in the system. Both crystals planes (0001) Al2O3 and (111) Al2MgO4 have crystallographic surfaces with identical O-2 crystalline positions however considering Mg2+ content in Al2MgO4 structure may influence a reactive mode. Kinetic models results under similar experimental conditions show that Al wetting on (0001) Al2O3 is less reactive than (111) Al2MgO4, however at >1273 K (1000 °C) (0001) Al2O3 transformation occurs and a transition of wetting improves. The (111) Al2MgO4 and Al system promotes interface formations that slow its wetting process.

  15. Enzymes on material surfaces.

    PubMed

    Talbert, Joey N; Goddard, Julie M

    2012-05-01

    Enzyme interactions with material surfaces are of interest for industrial food and pharmaceutical transformations, biosensors, artificial cells, cell free reactions, drug and nutrition delivery technologies, and imaging. When in contact with a material surface, an enzyme may lose or appear to lose activity due to the nature of the enzyme, the nature of the material, and/or the nature of the interface between the enzyme, material, and substrate environment. The purpose of this review is to survey recent advances that have been made towards the preservation, optimization, and enhancement of enzyme activity on material surfaces within the context of well-known concepts that describe the loss of activity after immobilization. This review breaks down the immobilized enzyme system to look at the individual components of the system-namely the enzyme, the material, and the interface. For each piece, possible causes for the loss of enzyme activity are described as well as strategies that have been applied to limit the affect. At the conclusion we identify areas of future research needed to overcome limitations in the current state-of-the art for immobilized enzyme systems.

  16. Surface analysis in microelectronics.

    PubMed

    Pignataro, S

    1995-10-01

    The contribution given by surface analysis to solve some problems encountered in the production of electronic power devices have been discussed. Mainly two types of problems have been faced. One of these deal with interfacial chemistry. Three examples have been investigated. The first applies to the improvement of the quality and the reliability of plastic packages through the optimization of the resin/metal and resin/die adhesion. The second relies to the adhesion between polyimide and silicon nitride used in the multilevel technology. The third example refers to the so called die-attach process and related problems. Another area of interest in microelectronics is that of the erosion of various types of surfaces and the possibility of wrong etching. A few examples of the application of surface analytical techniques for these problems will be presented. XPS and SIMS working in imaging and multipoint analysis mode, scanning acoustic microscopy, contact angle measurements as well as peeling and tensile strength measurements are the main tools used to obtain useful data.

  17. High surface area calcite

    NASA Astrophysics Data System (ADS)

    Schultz, L. N.; Andersson, M. P.; Dalby, K. N.; Müter, D.; Okhrimenko, D. V.; Fordsmand, H.; Stipp, S. L. S.

    2013-05-01

    Calcite (CaCO3) is important in many fields—in nature, because it is a component of aquifers, oil reservoirs and prospective CO2 storage sites, and in industry, where it is used in products as diverse as paper, toothpaste, paint, plastic and aspirin. It is difficult to obtain high purity calcite with a high surface area but such material is necessary for industrial applications and for fundamental calcite research. Commercial powder is nearly always contaminated with growth inhibitors such as sugars, citrate or pectin and most laboratory synthesis methods deliver large precipitates, often containing vaterite or aragonite. To address this problem, we (i) adapted the method of carbonating a Ca(OH)2 slurry with CO2 gas to develop the first simple, cheap, safe and reproducible procedure using common laboratory equipment, to obtain calcite that reproducibly had a surface area of 14-17 m2/g and (ii) conducted a thorough characterization of the product. Scanning electron microscopy (SEM) revealed nanometer scale, rhombohedral crystals. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) confirmed highly crystalline, pure calcite that more closely resembles the dimensions of the biogenic calcite produced by algae in coccoliths than other methods for synthesizing calcite. We suggest that this calcite is useful when purity and high surface area are important.

  18. Microplates with adaptive surfaces.

    PubMed

    Akbulut, Meshude; Lakshmi, Dhana; Whitcombe, Michael J; Piletska, Elena V; Chianella, Iva; Güven, Olgun; Piletsky, Sergey A

    2011-11-14

    Here we present a new and versatile method for the modification of the well surfaces of polystyrene microtiter plates (microplates) with poly(N-phenylethylene diamine methacrylamide), (poly-NPEDMA). The chemical grafting of poly-NPEDMA to the surface of microplates resulted in the formation of thin layers of a polyaniline derivative bearing pendant methacrylamide double bonds. These were used as the attachment point for various functional polymers through photochemical grafting of various, for example, acrylate and methacrylate, polymers with different functionalities. In a model experiment, we have modified poly-NPEDMA-coated microplates with a small library of polymers containing different functional groups using a two-step approach. In the first step, double bonds were activated by UV irradiation in the presence of N,N-diethyldithiocarbamic acid benzyl ester (iniferter). This enabled grafting of the polymer library in the second step by UV irradiation of solutions of the corresponding monomers in the microplate wells. The uniformity of coatings was confirmed spectrophotometrically, by microscopic imaging and by contact angle measurements (CA). The feasibility of the current technology has been shown by the generation of a small library of polymers grafted to the microplate well surfaces and screening of their affinity to small molecules, such as atrazine, a trio of organic dyes, and a model protein, bovine serum albumin (BSA). The stability of the polymers, reproducibility of measurement, ease of preparation, and cost-effectiveness make this approach suitable for applications in high-throughput screening in the area of materials research.

  19. Lateral engineering of surface states - towards surface-state nanoelectronics.

    PubMed

    García de Abajo, F J; Cordón, J; Corso, M; Schiller, F; Ortega, J E

    2010-05-01

    Patterned metal surfaces can host electron quantum waves that display interference phenomena over distances of a few nanometres, thus providing excellent information carriers for future atomic-scale devices. Here we demonstrate that collimation and waveguiding of surface electrons can be realized in silver-induced strain dislocation networks on Cu(111) surfaces, as a conceptual proof-of-principle of surface-state nanoelectronics (SSNE). The Ag/Cu(111) system exhibits featured surface bands with gaps at the Fermi energy, which are basic requirements for a potential SSNE material. We establish a solid analogy between the behavior of surface-state electrons and surface plasmons in patterned metal surfaces, thus facilitating the transfer of existing knowledge on plasmonic structures to the new scenario presented by engineered electronic surface-state nanostructures, with the advantage of a 1000-fold reduction in wavelength and geometrical parameters.

  20. Surface structure and stability of partially hydroxylated silica surfaces

    DOE PAGES

    Rimsza, J. M.; Jones, R. E.; Criscenti, L. J.

    2017-04-04

    Surface energies of silicates influence crack propagation during brittle fracture and decrease with surface relaxation caused by annealing and hydroxylation. Molecular-level simulations are particularly suited for the investigation of surface processes. In this work, classical MD simulations of silica surfaces are performed with two force fields (ClayFF and ReaxFF) to investigate the effect of force field reactivity on surface structure and energy as a function of surface hydroxylation. An unhydroxylated fracture surface energy of 5.1 J/m2 is calculated with the ClayFF force field, and 2.0 J/m2 is calculated for the ReaxFF force field. The ClayFF surface energies are consistent withmore » the experimental results from double cantilever beam fracture tests (4.5 J/m2), whereas ReaxFF underestimated these surface energies. Surface relaxation via annealing and hydroxylation was performed by creating a low-energy equilibrium surface. Annealing condensed neighboring siloxane bonds increased the surface connectivity, and decreased the surface energies by 0.2 J/m2 for ClayFF and 0.8 J/m2 for ReaxFF. Posthydroxylation surface energies decreased further to 4.6 J/m2 with the ClayFF force field and to 0.2 J/m2 with the ReaxFF force field. Experimental equilibrium surface energies are ~0.35 J/m2, consistent with the ReaxFF force field. Although neither force field was capable of replicating both the fracture and equilibrium surface energies reported from experiment, each was consistent with one of these conditions. Furthermore, future computational investigations that rely on accurate surface energy values should consider the surface state of the system and select the appropriate force field.« less

  1. Surface nanobubbles and micropancakes

    NASA Astrophysics Data System (ADS)

    Seddon, James R. T.

    2013-05-01

    When looking at a wetted surface with a technique that can probe the nanoscale, a high surface coverage of gas bubbles is often revealed. So what? Well, if we believe in classical diffusion, these bubbles should dissolve in microseconds, but in reality they are found to remain stable for as long as anyone has observed (five days thus far, which is 10-11 orders of magnitude longer than would be expected). As well as the obvious question of why the lifetime is so long, and also the question of how the bubbles nucleate in the first place, we rapidly find ourselves asking can we use the bubbles to our benefit? A clear example would be in controlling slip in micro/nanofluidics: effectively, replacing a solid wall with a 'gassy' wall replaces the no-slip boundary condition with one of slip. Several other potential applications have also been suggested and nanobubbles have, in fact, already proven useful in the antifouling world. Returning to fundamentals, another near-wall gas domain has also come to light through our investigations into nanobubbles. The micropancake is thought to be a quasi-2D dense adsorbate of gas molecules (i.e. N2 or O2) which grows epitaxially on the surface. New questions now include: why are micropancakes stable, how do they form, and what is their relationship with nanobubbles? Progress is being made in this field and, as with all new topics, the community is rapidly converging toward a standard set of 'minimum' requirements for scientific reporting. For example, taking single-shot atomic force microscopy data is almost definitely no longer sufficient to be additive to the field (there are far too many unrepeatable single-shot measurements in the literature which are too often used as 'evidence', even though there are a seemingly equal number of single-shot measurements that may disagree). Just quoting a 'set-point' is now also insufficient (both set-point and free (or interaction) amplitude are required to know the applied force of an AFM

  2. Surface alloying of Mg alloys after surface nanocrystallization.

    PubMed

    Zhang, Ming-Xing; Shi, Yi-Nong; Sun, Haiqing; Kelly, Patrick M

    2008-05-01

    Surface nanocrystallization using a surface mechanical attrition treatment effectively activates the surface of magnesium alloys due to the increase in grain boundary diffusion channels. As a result, the temperature of subsequent surface alloying treatment of pure Mg and AZ91 alloy can be reduced from 430 degrees C to 380 degrees C. Thus, it is possible to combine the surface alloying process with the solution treatment for this type of alloy. After surface alloying, the hardness of the alloyed layer is 3 to 4 times higher than that of the substrate and this may significantly improve the wear resistance of magnesium alloys.

  3. Surface forces: Surface roughness in theory and experiment

    SciTech Connect

    Parsons, Drew F. Walsh, Rick B.; Craig, Vincent S. J.

    2014-04-28

    A method of incorporating surface roughness into theoretical calculations of surface forces is presented. The model contains two chief elements. First, surface roughness is represented as a probability distribution of surface heights around an average surface height. A roughness-averaged force is determined by taking an average of the classic flat-surface force, weighing all possible separation distances against the probability distributions of surface heights. Second the model adds a repulsive contact force due to the elastic contact of asperities. We derive a simple analytic expression for the contact force. The general impact of roughness is to amplify the long range behaviour of noncontact (DLVO) forces. The impact of the elastic contact force is to provide a repulsive wall which is felt at a separation between surfaces that scales with the root-mean-square (RMS) roughness of the surfaces. The model therefore provides a means of distinguishing between “true zero,” where the separation between the average centres of each surface is zero, and “apparent zero,” defined by the onset of the repulsive contact wall. A normal distribution may be assumed for the surface probability distribution, characterised by the RMS roughness measured by atomic force microscopy (AFM). Alternatively the probability distribution may be defined by the histogram of heights measured by AFM. Both methods of treating surface roughness are compared against the classic smooth surface calculation and experimental AFM measurement.

  4. Ultrasonic approach for surface nanostructuring.

    PubMed

    Skorb, Ekaterina V; Möhwald, Helmuth

    2016-03-01

    The review is about solid surface modifications by cavitation induced in strong ultrasonic fields. The topic is worth to be discussed in a special issue of surface cleaning by cavitation induced processes since it is important question if we always find surface cleaning when surface modifications occur, or vice versa. While these aspects are extremely interesting it is important for applications to follow possible pathways during ultrasonic treatment of the surface: (i) solely cleaning; (ii) cleaning with following surface nanostructuring; and (iii) topic of this particular review, surface modification with controllably changing its characteristics for advanced applications. It is important to know what can happen and which parameters should be taking into account in the case of surface modification when actually the aim is solely cleaning or aim is surface nanostructuring. Nanostructuring should be taking into account since is often accidentally applied in cleaning. Surface hydrophilicity, stability to Red/Ox reactions, adhesion of surface layers to substrate, stiffness and melting temperature are important to predict the ultrasonic influence on a surface and discussed from these points for various materials and intermetallics, silicon, hybrid materials. Important solid surface characteristics which determine resistivity and kinetics of surface response to ultrasonic treatment are discussed. It is also discussed treatment in different solvents and presents in solution of metal ions. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Laser heterodyne surface profiler

    DOEpatents

    Sommargren, G.E.

    1980-06-16

    A method and apparatus are disclosed for testing the deviation of the face of an object from a flat smooth surface using a beam of coherent light of two plane-polarized components, one of a frequency constantly greater than the other by a fixed amount to produce a difference frequency with a constant phase to be used as a reference, and splitting the beam into its two components. The separate components are directed onto spaced apart points on the face of the object to be tested for smoothness while the face of the object is rotated on an axis normal to one point, thereby passing the other component over a circular track on the face of the object. The two components are recombined after reflection to produce a reflected frequency difference of a phase proportional to the difference in path length of one component reflected from one point to the other component reflected from the other point. The phase of the reflected frequency difference is compared with the reference phase to produce a signal proportional to the deviation of the height of the surface along the circular track with respect to the fixed point at the center, thereby to produce a signal that is plotted as a profile of the surface along the circular track. The phase detector includes a quarter-wave plate to convert the components of the reference beam into circularly polarized components, a half-wave plate to shift the phase of the circularly polarized components, and a polarizer to produce a signal of a shifted phase for comparison with the phase of the frequency difference of the reflected components detected through a second polarizer. Rotation of the half-wave plate can be used for phase adjustment over a full 360/sup 0/ range.

  6. Pluto's Surface in Detail

    NASA Image and Video Library

    2017-07-14

    On July 14, 2015, NASA's New Horizons spacecraft made its historic flight through the Pluto system. This detailed, high-quality global mosaic of Pluto was assembled from nearly all of the highest-resolution images obtained by the Long-Range Reconnaissance Imager (LORRI) and the Multispectral Visible Imaging Camera (MVIC) on New Horizons. The mosaic is the most detailed and comprehensive global view yet of Pluto's surface using New Horizons data. It includes topography data of the hemisphere visible to New Horizons during the spacecraft's closest approach. The topography is derived from digital stereo-image mapping tools that measure the parallax -- or the difference in the apparent relative positions -- of features on the surface obtained at different viewing angles during the encounter. Scientists use these parallax displacements of high and low terrain to estimate landform heights. The global mosaic has been overlain with transparent, colorized topography data wherever on the surface stereo data is available. Terrain south of about 30°S was in darkness leading up to and during the flyby, so is shown in black. Examples of large-scale topographic features on Pluto include the vast expanse of very flat, low-elevation nitrogen ice plains of Sputnik Planitia ("P") -- note that all feature names in the Pluto system are informal -- and, on the eastern edge of the encounter hemisphere, the aligned, high-elevation ridges of Tartarus Dorsa ("T") that host the enigmatic bladed terrain, mountains, possible cryovolcanos, canyons, craters and more. https://photojournal.jpl.nasa.gov/catalog/PIA21861

  7. Operationalizing Surface Piercing Profilers

    NASA Astrophysics Data System (ADS)

    Fram, J. P.; Barth, J. A.; Dever, E. P.; Rhoades, B.; Koegler, J. M.

    2016-02-01

    High vertical resolution profiles of surface waters with multi-parameter sensor packages are valuable for understanding coupled physical-biogeochemical ocean processes. Typically, these profilers are only able to be used for short periods of time due to lack of ruggedness, reliability, automation, and battery life. Over the last three years, the Ocean Observatories Initiative has partnered with WET Labs to improve a set of WET Labs Thetis profilers so that OOI can operate six of them year-round in waters up to 100 m in depth. These profiles sample 1-16 Hz while rising 25 cm/s. They include 8 instruments with more than a dozen sensors, and they have room for more. A smart winch on-board these profilers compensates for wave-driven heave, which enables them to surface and telemeter data via Iridium in up to 3 m waves, 10 m/s winds, and 40 cm/s mean water currents. Multiple firmware and electronics upgrades enable these profilers to automatically recover from problems, or at least put themselves in a state that minimizes the chance of loss/damage and allows for remote query & control via acoustic modem from a neighboring surface mooring. These and other improvements enable the system to capture periods of the year such as the beginning of the annual coastal upwelling-dominated period without fear from damage by spring storms. This contribution will show the new features, the overall capabilities, and the limitations of these profilers, and it will show what data are available from them through OOI.

  8. Nature Inspired Surface Coatings

    NASA Astrophysics Data System (ADS)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  9. Modeling of surface reactions

    SciTech Connect

    Ray, T.R.

    1993-01-01

    Mathematical models are used to elucidate properties of the monomer-monomer and monomer-dimer type chemical reactions on a two-dimensional surface. The authors use mean-field and lattice gas models, detailing similarities and differences due to correlations in the lattice gas model. The monomer-monomer, or AB surface reaction model, with no diffusion, is investigated for various reaction rates k. Study of the exact rate equations reveals that poisoning always occurs if the adsorption rates of the reactants are unequal. If the adsorption rates of the reactants are equal, simulations show slow poisoning, associated with clustering of reactants. This behavior is also shown for the two-dimensional voter model. The authors analyze precisely the slow poisoning kinetics by an analytic treatment for the AB reaction with infinitesimal reaction rate, and by direct comparison with the voter model. They extend the results to incorporate the effects of place-exchange diffusion, and they compare the AB reaction with infinitesimal reaction rate and no diffusion to the voter model with diffusion at rate 1/2. They also consider the relationship of the voter model to the monomer-dimer model, and investigate the latter model for small reaction rates. The monomer-dimer, or AB[sub 2] surface reaction model is also investigated. Specifically, they consider the ZGB-model for CO-oxidation, and in generalizations of this model which include adspecies diffusion. A theory of nucleation to describe properties of non-equilibrium first-order transitions, specifically the evolution between [open quote]reactive[close quote] steady states and trivial adsorbing states, is derived. The behavior of the [open quote]epidemic[close quote] survival probability, P[sub s], for a non-poisoned patch surrounded by a poisoned background is determined below the poisoning transition.

  10. The martian surface.

    PubMed

    Opik, E J

    1966-07-15

    With the scarcity of factual data and the difficulty of applying crucial tests, many of the properties of the Martian surface remain a mystery; the planet may become a source of great surprises in the future. In the following, the conclusions are enumerated more or less in the order of their reliability, the more certain ones first, conjectures or ambiguous interpretations coming last. Even if they prove to be wrong, they may serve as a stimulus for further investigation. Impact craters on Mars, from collisions with nearby asteroids and other stray bodies, were predicted 16 years ago (5-7) and are now verified by the Mariner IV pictures. The kink in the frequency curve of Martian crater diameters indicates that those larger than 20 kilometers could have survived aeolian erosion since the "beginning." They indicate an erosion rate 30 times slower than that in terrestrial deserts and 70 times faster than micrometeorite erosion on the moon. The observed number, per unit area, of Martian craters larger than 20 kilometers exceeds 4 times that calculated from the statistical theory of interplanetary collisions with the present population of stray bodies and for a time interval of 4500 million years, even when allowance is made for the depletion of the Martian group of asteroids, which were more numerous in the past. This, and the low eroded rims of the Martian craters suggest that many of the craters have survived almost since the formation of the crust. Therefore, Mars could not have possessed a dense atmosphere for any length of time. If there was abundant water for the first 100 million years or so, before it escaped it could have occurred only in the solid state as ice and snow, with but traces of vapor in the atmosphere, on account of the low temperature caused by the high reflectivity of clouds and snow. For Martian life there is thus the dilemma: with water, it is too cold; without, too dry. The crater density on Mars, though twice that in lunar maria, is much

  11. Semiconductor surface protection material

    NASA Technical Reports Server (NTRS)

    Packard, R. D. (Inventor)

    1973-01-01

    A method and a product for protecting semiconductor surfaces is disclosed. The protective coating material is prepared by heating a suitable protective resin with an organic solvent which is solid at room temperature and converting the resulting solution into sheets by a conventional casting operation. Pieces of such sheets of suitable shape and thickness are placed on the semiconductor areas to be coated and heat and vacuum are then applied to melt the sheet and to drive off the solvent and cure the resin. A uniform adherent coating, free of bubbles and other defects, is thus obtained exactly where it is desired.

  12. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  13. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  14. TREATMENT OF URANIUM SURFACES

    DOEpatents

    Slunder, C.J.

    1959-02-01

    An improved process is presented for prcparation of uranium surfaces prior to electroplating. The surfacc of the uranium to be electroplated is anodized in a bath comprising a solution of approximately 20 to 602 by weight of phosphoric acid which contains about 20 cc per liter of concentrated hydrochloric acid. Anodization is carried out for approximately 20 minutes at a current density of about 0.5 amperes per square inch at a temperature of about 35 to 45 C. The oxidic film produced by anodization is removed by dipping in strong nitric acid, followed by rinsing with water just prior to electroplating.

  15. Scattering from Superquadric Surfaces

    DTIC Science & Technology

    1988-06-01

    for any purpose other than in connection with a definitely related Government procurement operation, the United States Government thereby incurs no...Clomparative C’PU times in VPU (VAX 780 Processing Units ) 44 3 I I I I I I I I I I * Chapter 1 | INTRODUCTION I The electromagnetic scattering from a...in the Shadow region (2.4) where ft is the unit normal to the surface. Physical Optics is useful because the form of the assumed currents is 3 simple

  16. Surface modified aerogel monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

    2013-01-01

    This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

  17. Stability at the surface

    SciTech Connect

    Chambers, Scott A.

    2014-12-05

    Metal oxides are ubiquitous as minerals in the terrestrial environment, as well as in a variety of technologically important structures such as electronic devices and heterogeneous catalysts. Within these various contexts, interfaces between oxides and gases, liquids and solids drive many critically important phenomena ranging from the uptake of contaminants in groundwater by redox-active minerals to the switching of the millions of transistors found in every cell phone and computer. Function is tied to structure. Therefore, fundamental understanding of the structure of oxide surfaces and interfaces is of crucial importance to the comprehension of a plethora of phenomena involving this broad class of materials.

  18. Martian Surface Beneath Phoenix

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an image of the Martian surface beneath NASA's Phoenix Mars Lander. The image was taken by Phoenix's Robotic Arm Camera (RAC) on the eighth Martian day of the mission, or Sol 8 (June 2, 2008). The light feature in the middle of the image below the leg is informally called 'Holy Cow.' The dust, shown in the dark foreground, has been blown off of 'Holy Cow' by Phoenix's thruster engines.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Surface-Mediated Photocatalysis

    DTIC Science & Technology

    1992-02-04

    Dulay, Debra Washington-Dedeaux, and Marye Anne Fox, Photochem. Photobiol. A.: Photochem. 1991, 61, 153. " Photodegradation of Benzamide in TiO2 Aqueous...ATrR rPY KEEP THIS COPY FOR REPRODUCTION PURPOSES 9Form Approved-A249 906 TION PAGE OMB No. 0704-0188 P 111 ii 111 1 11 lii!II I ii 1i ., age * ot zer...Produced by Anodic Oxidation and by Photoelectrochemical Activation of TiO2 ," Marye Anne Fox and Karl L. Worthen, Chem. Mater. 1991, 3, 253. "Surface

  20. Bioelectrochemistry of cell surfaces

    NASA Astrophysics Data System (ADS)

    Dolowy, Krzysztof

    This paper deals with processes and phenomena of cell surface bioelectrochemistry in which charges do not move across the cell membrane. First, electrochemical properties of the cell membrane and the cell medium interface are described, and different electric potentials present in biological systems are defined. Methods of cell electrophoresis are then discussed. It is shown that none of the simple electrochemical models of the cell membrane can explain the dependence of cell electrophoretic mobility upon ionic strength and other electrochemical properties of the cell membrane, such as the difference in cell membrane charge as determined electrochemically and biochemically, or the effect of neuraminidase, pH, or membrane potential change on cell electrophoretic mobility. Thus, it is apparent that conclusions drawn from electrophoretic mobility data on the basis of simple models are false. The more complex multilayer-electrochemical model of the cell membrane is then described and shown to explain most electrochemical properties of the cell membrane. Next, different electrochemical techniques that were applied to study cell surfaces are described. It is shown that colloid titration, isoelectric focusing, and partition of cells between two immiscible phases is dependent not only on electrical properties of the cell membrane, but also on the energy of adsorption at cell surfaces of organic molecules used in these methods. Powder electrodes, cell polarography, conductometric titration, and Donnan potential methods are described and it is shown that these methods also produce results of doubtful value and are also often misinterpreted. The contact potential difference method produces results difficult to interpret and only electro-osmotic measurements and potential sensitive molecules are valuable methods. The colloid particle interaction theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) as applied to cell interactions is discussed. It is shown that the

  1. Martian Surface Beneath Phoenix

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is an image of the Martian surface beneath NASA's Phoenix Mars Lander. The image was taken by Phoenix's Robotic Arm Camera (RAC) on the eighth Martian day of the mission, or Sol 8 (June 2, 2008). The light feature in the middle of the image below the leg is informally called 'Holy Cow.' The dust, shown in the dark foreground, has been blown off of 'Holy Cow' by Phoenix's thruster engines.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  2. Surface Production of Ions

    DTIC Science & Technology

    1989-10-09

    as converter surfaces and are reproducible in day-to-day operation . Exposure to atomic hydrogen (up = mmmmmmmm mmmm m lk"--m ml6 to a flux of 5 x...synthetic zeolite of the formula Cs20.AtO 3.10 SiO 2. The pellet is operated at a temperature of 10000C at vhich temperature the zeolite is a good...Cs+ ion emission current density up to 10 mKA/cm 2 has been extracted for 500 hours at 11OOoC in steady state operation . The emission current can be

  3. Monitoring the analytic surface.

    PubMed

    Spence, D P; Mayes, L C; Dahl, H

    1994-01-01

    How do we listen during an analytic hour? Systematic analysis of the speech patterns of one patient (Mrs. C.) strongly suggests that the clustering of shared pronouns (e.g., you/me) represents an important aspect of the analytic surface, preconsciously sensed by the analyst and used by him to determine when to intervene. Sensitivity to these patterns increases over the course of treatment, and in a final block of 10 hours shows a striking degree of contingent responsivity: specific utterances by the patient are consistently echoed by the analyst's interventions.

  4. Martian surface coordinates

    NASA Technical Reports Server (NTRS)

    Davies, M. E.; Arthur, D. W. G.

    1973-01-01

    Methods and results are presented for primary and secondary triangulation of the Martian surface. The primary network is based on multiphotograph stereophotogrammetry in which the pictures are rotated around fixed centers; these centers are provided as spacecraft stations from the tracking data. The computations use the latest Mars spin axis determined by Mariner 9 experiments and the new first meridian passing through a small crater, Airy-O, seen on Mariner 9 imagery. The secondary triangulation is performed in the map plane using rectified pictures as map fragments, assumed to be of correct shape. Primary positions are given.

  5. SAMOS Surface Fluxes

    NASA Astrophysics Data System (ADS)

    Smith, Shawn; Bourassa, Mark

    2014-05-01

    The development of a new surface flux dataset based on underway meteorological observations from research vessels will be presented. The research vessel data center at the Florida State University routinely acquires, quality controls, and distributes underway surface meteorological and oceanographic observations from over 30 oceanographic vessels. These activities are coordinated by the Shipboard Automated Meteorological and Oceanographic System (SAMOS) initiative in partnership with the Rolling Deck to Repository (R2R) project. Recently, the SAMOS data center has used these underway observations to produce bulk flux estimates for each vessel along individual cruise tracks. A description of this new flux product, along with the underlying data quality control procedures applied to SAMOS observations, will be provided. Research vessels provide underway observations at high-temporal frequency (1 min. sampling interval) that include navigational (position, course, heading, and speed), meteorological (air temperature, humidity, wind, surface pressure, radiation, rainfall), and oceanographic (surface sea temperature and salinity) samples. Vessels recruited to the SAMOS initiative collect a high concentration of data within the U.S. continental shelf and also frequently operate well outside routine shipping lanes, capturing observations in extreme ocean environments (Southern, Arctic, South Atlantic, and South Pacific oceans). These observations are atypical for their spatial and temporal sampling, making them very useful for many applications including validation of numerical models and satellite retrievals, as well as local assessments of natural variability. Individual SAMOS observations undergo routine automated quality control and select vessels receive detailed visual data quality inspection. The result is a quality-flagged data set that is ideal for calculating turbulent flux estimates. We will describe the bulk flux algorithms that have been applied to the

  6. Deflation of elastic surfaces

    NASA Astrophysics Data System (ADS)

    Quilliet, Catherine

    2011-03-01

    The deflation of elastic spherical surfaces has been numerically investigated, and show very different types of deformations according the range of elastic parameters, some of them being quantitatively understood through simple theoretical considerations. In particular, the role of the Poisson ratio is closely investigated. This work allowed to retrieve various shapes observed on hollow deformable shells (from colloidal to centimeter scale), on lipid vesicles, or on some simple biological objects. Conversely, it shows how high deformations can tell observers about mechanical properties of a body. Such investigations have been extended to other geometries, in order to provide clues to understand deformations of vegetal or animal tissues.

  7. Spacecraft Surface Charging Handbook

    DTIC Science & Technology

    1992-11-01

    Briet, and A. L. Vampola of Aerospace Corporation , H. R. Anderson, A. Holman, and J. Manderesse of SAIC, L. Levy of CERT, R. Viswanathan, G. Barbay, P...camWat a8n truss piece comnat Proper truss to not possible, so eftend res and en OCYA"O axis 0 0 0 0 0 1 width 6 side 2 surface teflon surftce - teflon...p. 62, 1974. Rudie, N. J., et a]., Design Support Guide fior Radiation Hardening oif Space Electronics Svsitems. I RT Corporation , I RT 6409-001, 198

  8. Asteroid and comet surfaces

    NASA Technical Reports Server (NTRS)

    Mcfadden, Lucy-Ann

    1988-01-01

    Photometric and spectrophotometric studies of asteroids and comets are in progress to address questions about the mineralogical relationship between asteroids near the 3:1 Kirkwood gap and ordinary chondrite meteorites and between cometary nuclei and the surface of asteroids. Progress was made on a method to convert the measured excess UV flux in the spectrum of 2201 Oljato to column abundance of OH and CN. Spectral reflectance measurements of large asteroids near the 3:1 Kirkwood gap, which is expected to be the source of ordinary chondrite meteorites, were briefly examined and show no spectral signatures that are characteristic of ordinary chondrite meteorite powders measured in the lab.

  9. Comparative study of the surface layer density of liquid surfaces

    NASA Astrophysics Data System (ADS)

    Chacón, E.; Fernández, E. M.; Duque, D.; Delgado-Buscalioni, R.; Tarazona, P.

    2009-11-01

    Capillary wave fluctuations blur the inherent structure of liquid surfaces in computer simulations. The intrinsic sampling method subtracts capillary wave fluctuations and yields the intrinsic surface structure, leading to a generic picture of the liquid surface. The most relevant magnitude of the method is the surface layer density ns that may be consistently determined from different properties: the layering structure of the intrinsic density profiles, the turnover rate for surface layer particles, and the hydrodynamic damping rate of capillary waves. The good agreement among these procedures provides evidence for the physical consistency of the surface layering hypothesis, as an inherent physical property of the liquid surfaces. The dependence of the surface compactness, roughness, and exchange rate with temperature is analyzed for several molecular interaction models.

  10. Modern Introduction to Surface Plasmons

    NASA Astrophysics Data System (ADS)

    Sarid, Dror; Challener, William

    2010-05-01

    1. Introduction; 2. Electromagnetics of planar surface waves; 3. Single-interface modes in the microwave regime; 4. Single-interface lossless modes in ɛr'-μr' parameter space; 5. Double-interface lossless modes in ɛr'-μr' parameter space; 6. Single-interface surface plasmons; 7. Double-interface surface plasmons in symmetric guides; 8. Quasi one-dimensional surface plasmons; 9. Localized surface plasmons; 10. Techniques for exciting surface plasmons; 11. Plasmonic materials; 12. Applications; Appendixes; Index.

  11. Surface photovoltage spectroscopy applied to gallium arsenide surfaces

    NASA Technical Reports Server (NTRS)

    Bynik, C. E.

    1975-01-01

    The experimental and theoretical basis for surface photovoltage spectroscopy is outlined. Results of this technique applied to gallium arsenide surfaces, are reviewed and discussed. The results suggest that in gallium arsenide the surface voltage may be due to deep bulk impurity acceptor states that are pinned at the Fermi level at the surface. Establishment of the validity of this model will indicate the direction to proceed to increase the efficiency of gallium arsenide solar cells.

  12. Surface tension of spherical drops from surface of tension

    SciTech Connect

    Homman, A.-A.; Bourasseau, E.; Malfreyt, P.; Strafella, L.; Ghoufi, A.

    2014-01-21

    The determination of surface tension of curved interfaces is a topic that raised many controversies during the last century. Explicit liquid-vapor interface modelling (ELVI) was unable up to now to reproduce interfacial behaviors in drops due to ambiguities in the mechanical definition of the surface tension. In this work, we propose a thermodynamic approach based on the location of surface of tension and its use in the Laplace equation to extract the surface tension of spherical interfaces from ELVI modelling.

  13. Multilayer Relaxation and Surface Energies of Metallic Surfaces

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Rodriguez, Agustin M.; Ferrante, John

    1994-01-01

    The perpendicular and parallel multilayer relaxations of fcc (210) surfaces are studied using equivalent crystal theory (ECT). A comparison with experimental and theoretical results is made for AI(210). The effect of uncertainties in the input parameters on the magnitudes and ordering of surface relaxations for this semiempirical method is estimated. A new measure of surface roughness is proposed. Predictions for the multilayer relaxations and surface energies of the (210) face of Cu and Ni are also included.

  14. Global Surface Temperature Change

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Ruedy, R.; Sato, M.; Lo, K.

    2010-12-01

    We update the Goddard Institute for Space Studies (GISS) analysis of global surface temperature change, compare alternative analyses, and address questions about perception and reality of global warming. Satellite-observed night lights are used to identify measurement stations located in extreme darkness and adjust temperature trends of urban and periurban stations for nonclimatic factors, verifying that urban effects on analyzed global change are small. Because the GISS analysis combines available sea surface temperature records with meteorological station measurements, we test alternative choices for the ocean data, showing that global temperature change is sensitive to estimated temperature change in polar regions where observations are limited. We use simple 12 month (and n × 12) running means to improve the information content in our temperature graphs. Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior 2 decades, despite year-to-year fluctuations associated with the El Niño-La Niña cycle of tropical ocean temperature. Record high global 12 month running mean temperature for the period with instrumental data was reached in 2010.

  15. Laser heterodyne surface profiler

    DOEpatents

    Sommargren, Gary E.

    1982-01-01

    A method and apparatus is disclosed for testing the deviation of the face of an object from a flat smooth surface using a beam of coherent light of two plane-polarized components, one of a frequency constantly greater than the other by a fixed amount to produce a difference frequency with a constant phase to be used as a reference. The beam also is split into its two components with the separate components directed onto spaced apart points onthe face of the object to be tested for smoothness. The object is rotated on an axis coincident with one component which is directed to the face of the object at the center which constitutes a virtual fixed point. This component also is used as a reference. The other component follows a circular track on the face of the object as the object is rotated. The two components are recombined after reflection to produce a reflected frequency difference of a phase proportional to the difference in path length which is compared with the reference phase to produce a signal proportional to the deviation of the height of the surface along the circular track with respect to the fixed point at the center.

  16. Surface Characterization and Contamination

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1999-01-01

    Nondestructive characterization of surface contamination can play an extremely important role in improving quality in manufacturing processes. This area of interest led to the formation of a Surface Contamination Analysis Team (SCAT) at Marshall Space Flight Center, which is primarily concerned with critical bondlines and has provided the major focus for activities under this grant. In addition, determining minute levels of contamination on emerging aerospace systems fabricated from composites has also been an area of interest for which the methods being presented here can be used. Important considerations for the inspection methodologies are good sensitivity, large area coverage, robustness, portability and ease of use for normal production personnel. In parallel with the evaluation of detection methods, considerable effort has been made to developing good, uniform contamination films to use as calibration standards. This activity within itself has presented unique challenges. The development of NIR methods for detecting and identifying contaminants has been in progress for several years. Cooperative efforts between the University, NASA, and Thiokol Corporation has shown some useful results for implementation in both laboratory and on-line procedures.

  17. The Martian surface layer

    NASA Technical Reports Server (NTRS)

    Christensen, Philip R.; Moore, Henry J.

    1992-01-01

    The global characteristics of the Martian surface layer are discussed on the basis of thermal, albedo, color, and radar data for the region between approximately 60 deg S and 60 deg N. Thermal data reveal the presence of large low- and high-inertia regions of the northern hemisphere, with much of the south covered by material of moderate inertia. There is a strong anticorrelation between inertia and albedo, a correlation between inertia and rock abundance, and, over much of the planet, a correlation of radar-derived density with inertia. Viking Orbiter color data indicate the presence of three major surface materials: low-inertia, bright-red material that is presumably dust; high-inertia, dark-grey material interpreted to be lithic material mixed with palagonitelike dust; and moderate-inertia, dark-red material that is rough at subpixel scales and interpreted to be indurated. Observations from the Viking landing sites show rocks, fines of varying cohesion and crusts. These sites have indications of aeolian erosion and deposition in the recent past.

  18. Gale Crater Surface Materials

    NASA Image and Video Library

    2015-06-19

    Gale Crater, home to NASA's Curiosity Mars rover, shows a new face in this mosaic image made using data from the Thermal Emission Imaging System (THEMIS) on NASA's Mars Odyssey orbiter. The colors come from an image processing technique that identifies mineral differences in surface materials and displays them in false colors. For example, windblown dust appears pale pink and olivine-rich basalt looks purple. The bright pink on Gale's floor appears due to a mix of basaltic sand and windblown dust. The blue at the summit of Gale's central mound, Mount Sharp, probably comes from local materials exposed there. The typical average Martian surface soil looks grayish-green. Scientists use false-color images such as these to identify places of potential geologic interest. The diameter of the crater is 96 miles (154 kilometers). North is up. THEMIS and other instruments on Mars Odyssey have been studying Mars from orbit since 2001. Curiosity landed in the northeastern portion of Gale Crater in 2012 and climbed onto the flank of Mount Sharp in 2014. http://photojournal.jpl.nasa.gov/catalog/PIA19674

  19. Formaldehyde surface emission monitor

    SciTech Connect

    Matthews, T.G.; Hawthorne, A.R.; Daffron, C.R.; Corey, M.D.; Reed, T.J.; Schrimsher, J.M.

    1984-03-01

    A passive surface emission monitor has been developed for nondestructive measurement of formaldehyde (CH/sub 2/O) emission rates from CH/sub 2/O resin-containing materials such as urea-formaldehyde foam insulation (UFFI) and pressed-wood products. Emitted CH/sub 2/O is sorbed by a planar distribution of 13X molecular sleve supported inside the monitor and analyzed by using a water-rinse desorption, colorimetric analysis procedure. A detection limit of similarly ordered 0.025 mg of CH/sub 2/O/(M/sup 2/ h) is achieved with a 20.3 cm diameter monitor and a 2-h collection period. Measurements of CH/sub 2/O emission rates from pressed-wood products and UFFI encased in simulated wall panels show a strong correlation with reference chamber techniques. The surface monitor has been used to measure the CH/sub 2/O emission rate from interior walls and floors in one UFFI and two non-UFFI homes. By application of a simple single compartment model to predict indoor CH/sub 2/O concentrations from in situ CH/sub 2/O emission rate and tracer gas infiltration rate measurements, a good correlation between the predicted and measured CH/sub 2/O concentrations was achieved. 22 references, 5 figures, 4 tables.

  20. Laser heterodyne surface profiler

    DOEpatents

    Sommargren, Gary E.

    1984-01-01

    Method and apparatus for testing the deviation of the face of an object from a flat smooth surface using a laser beam having two plane-polarized components, one of a frequency greater than the other to produce a difference frequency with a phase to be used as a reference. The beam also is split into its two components which are directed onto spaced apart points on the face of the object. The object is rotated on an axis coincident with one component as a reference. The other component follows a circular track on the face of the object as the object is rotated. The two components are recombined after reflection to produce a difference frequency having a phase that is shifted in an amount that is proportional to the difference in path length as compared to the reference phase to produce an electrical output signal proportional to the deviation of the height of the surface along the circular track. The output signal is generated by means of a phase detector that includes a first photodetector in the path of the recombined components and a second photodetector in the path of the reference phase. The output signal is dependent on the phase difference of the two photodetector signals. A polarizer, a quarter-wave plate and a half-wave plate are in series in the path of the reference phase. Rotation of the half-wave plate can be used for phase adjustment over a full 360.degree. range for initial calibration of the apparatus.

  1. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K; Bhattacharya, R; Blau, Peter Julian; Clemons, Art; Eberle, Cliff; Evans, H B; Janke, Christopher James; Jolly, Brian C; Lee, E H; Leonard, Keith J; Trejo, Rosa M; Rivard, John D

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  2. Ocular surface reconstruction update.

    PubMed

    Shimmura, Shigeto; Tsubota, Kazuo

    2002-08-01

    Ocular surface reconstruction (OSR) is now a standard procedure in the treatment of severe ocular surface disorders. The past few years have revealed the long-term results of patients who were operated on during the early stages of OSR development, and we now have a more realistic view of the benefits and limits of the procedure. On the other hand, further understanding of the physiologic role played by the amniotic membrane (AM) has opened doors to further refined techniques in treating these patients. This review will introduce some of the major contributions made during the past years in the advancement of OSR. Clinically, we are at a stage of reviewing the pros and cons of the various transplantation techniques. Identification of factors crucial for a successful OSR procedure will further improve surgical results. Basic researchers are on the verge of identifying the so-called limbal stem cells, and further understanding of AM physiology will lead the way to tissue engineering techniques as another alternative in OSR surgery.

  3. Ocular surface temperature.

    PubMed

    Efron, N; Young, G; Brennan, N A

    1989-09-01

    A wide-field color-coded infra-red imaging device was applied to the measurement of i) the temperature profile across the ocular surface and ii) the temporal stability of central corneal temperature, on 21 subjects. The thermographs showed a pattern of ellipsoidal isotherms (major axis horizontal) approximately concentric about a temperature apex (coldest point) which was slightly inferior to the geometric center of the cornea (GCC). The GCC had a mean temperature (+/- SD) of 34.3 +/- 0.7 degrees C (range 32.8 to 35.4 degrees C). Temperature increased towards the periphery of the cornea with the limbus being 0.45 degrees C warmer than the GCC (p less than 0.0001). Following a blink, the GCC cooled at a mean (+/- SD) rate of 0.033 +/- 0.024 degrees C/s (p less than 0.0001) over the first 15s. Subjects whose corneas cooled more slowly following a blink demonstrated a greater capacity to avoid blinking for a prolonged period (p less than 0.05). This improved method of measuring ocular surface temperature has important applications in modeling corneal physiology and pathology.

  4. Surface Functionalized Nanocoax Biosensors

    NASA Astrophysics Data System (ADS)

    Rizal, Binod; Archibald, Michelle; McMahon, Gregory; Erdman, Natasha; Shepard, Stephen; Burns, Michael J.; Chiles, Thomas C.; Naughton, Michael J.

    2012-02-01

    We have adapted the nanocoax array architecture for high sensitivity, all-electronic chemical and biological sensing. We previously demonstrated ppb concentration level detection sensitivity to volatile organic compounds in dry air using the nanocoax array with nanoporous coax annuli [1]. Here, we report progress toward modifying/functionalizing the coax metal surfaces to enable specific binding of target molecules (e.g. proteins, toxins, pathogenic organisms), followed by electronic interrogation via capacitance/impedance spectroscopy. As a proxy for target molecules, and in order to confirm the ability to selectively functionalize desired surfaces in our nanopillar / nanocoax geometry, we have selectively attached strepavidin-functionalized core-shell CdSe/ZnS quantum dots to gold nanopillars. Next steps will include substituting antibodies for the quantum dots, and measuring the capacitance and impedance response to the introduction of protein (PSA , CA-125, etc.) in serum. Ref. [1]: H.Z. Zhao, B. Rizal, G. McMahon, H. Wang, P. Dhakal, T. Kirkpatrick, Z.F. Ren, T.C. Chiles, D. Cai and M.J. Naughton (submitted).

  5. Upscaling and downscaling of land surface fluxes with surface temperature

    USDA-ARS?s Scientific Manuscript database

    Land surface temperature (LST) is a key surface boundary condition that is significantly correlated to surface flux partitioning between latent and sensible heat. The spatial and temporal variation in LST is driven by radiation, wind, vegetation cover and roughness as well as soil moisture status ...

  6. Surface and guided waves on structured surfaces and inhomogeneous media

    NASA Astrophysics Data System (ADS)

    Polanco, Javier

    Surface and guided waves on structured surfaces and inhomogeneous media studies the propagation of waves in systems with spatially varying parameters. In the rainbow case (chapter 1), the dielectric constant changes with coordinates. In the cylinder case: boundary and the metal (chapter 2), it is a curved surface. Finally, in the last case (chapter 3), the dielectric constant changes in z-direction.

  7. Test surfaces useful for calibration of surface profilometers

    DOEpatents

    Yashchuk, Valeriy V; McKinney, Wayne R; Takacs, Peter Z

    2013-12-31

    The present invention provides for test surfaces and methods for calibration of surface profilometers, including interferometric and atomic force microscopes. Calibration is performed using a specially designed test surface, or the Binary Pseudo-random (BPR) grating (array). Utilizing the BPR grating (array) to measure the power spectral density (PSD) spectrum, the profilometer is calibrated by determining the instrumental modulation transfer.

  8. Relationship of wood surface energy to surface composition

    Treesearch

    Feipeng P. Liu; Timothy G. Rials; John Simonsen

    1998-01-01

    The wood cell wall is composed of cellulose, lignin, hemicelluloses, and extractives. Thus, the surface energy of the wood material must be some combination of the surface energies of these components. The influence of extractives on wood surface chemistry can be important in diverse industrial applications, such as coating, pulping, and wood-based composites. In this...

  9. Femtosecond laser-induced surface wettability modification of polystyrene surface

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Wang, XinCai; Zheng, HongYu; Lam, YeeCheong

    2016-12-01

    In this paper, we demonstrated a simple method to create either a hydrophilic or hydrophobic surface. With femtosecond laser irradiation at different laser parameters, the water contact angle (WCA) on polystyrene's surface can be modified to either 12.7° or 156.2° from its original WCA of 88.2°. With properly spaced micro-pits created, the surface became hydrophilic probably due to the spread of the water droplets into the micro-pits. While with properly spaced micro-grooves created, the surface became rough and more hydrophobic. We investigated the effect of laser parameters on WCAs and analyzed the laser-treated surface roughness, profiles and chemical bonds by surface profilometer, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). For the laser-treated surface with low roughness, the polar (such as C—O, C=O, and O—C=O bonds) and non-polar (such as C—C or C—H bonds) groups were found to be responsible for the wettability changes. While for a rough surface, the surface roughness or the surface topography structure played a more significant role in the changes of the surface WCA. The mechanisms involved in the laser surface wettability modification process were discussed.

  10. Attraction between hydrated hydrophilic surfaces

    NASA Astrophysics Data System (ADS)

    Kanduč, Matej; Schneck, Emanuel; Netz, Roland R.

    2014-08-01

    According to common knowledge, hydrophilic surfaces repel via hydration forces while hydrophobic surfaces attract, but mounting experimental evidence suggests that also hydrophilic surfaces can attract. Using all-atom molecular dynamics simulations at prescribed water chemical potential we study the crossover from hydration repulsion to hydrophobic attraction for planar polar surfaces of varying stiffness and hydrogen-bonding capability. Rescaling the partial charges of the polar surface groups, we cover the complete spectrum from very hydrophobic surfaces (characterized by contact angles θ ≃ 135°) to hydrophilic surfaces exhibiting complete wetting (θ = 0°). Indeed, for a finite range θadh < θ < 90°, we find a regime where hydrophilic surfaces attract at sub-nanometer separation and stably adhere without intervening water. The adhesive contact angle θadh depends on surface type and lies in the range 65° < θadh < 80°, in good agreement with experiments. Analysis of the total number of hydrogen bonds (HBs) formed by water and surface groups rationalizes this crossover between hydration repulsion and hydrophilic attraction in terms of a subtle balance: Highly polar surfaces repel because of strongly bound hydration water, less polar hydrophilic surfaces attract because water-water HBs are preferred over surface-water HBs. Such solvent reorganization forces presumably underlie also other important phenomena, such as selective ion adsorption to interfaces as well as ion pair formation.

  11. Computer representation of molecular surfaces

    SciTech Connect

    Max, N.L.

    1981-07-06

    This review article surveys recent work on computer representation of molecular surfaces. Several different algorithms are discussed for producing vector or raster drawings of space-filling models formed as the union of spheres. Other smoother surfaces are also considered.

  12. EPA Permeable Surface Research - Poster

    EPA Science Inventory

    EPA recognizes permeable surfaces as an effective post-construction infiltration-based Best Management Practice to mitigate the adverse effects of stormwater runoff. The professional user community conceptually embraces permeable surfaces as a tool for making runoff more closely...

  13. Research of Surface Roughness Anisotropy

    NASA Astrophysics Data System (ADS)

    Bulaha, N.; Rudzitis, J.; Lungevics, J.; Linins, O.; Krizbergs, J.

    2017-04-01

    The authors of the paper have investigated surfaces with irregular roughness for the purpose of determination of roughness spacing parameters perpendicularly to machining traces - RSm1 and parallel to them - RSm2, as well as checking the relationship between the surface anisotropy coefficient c and surface aspect ratio Str from the standard LVS EN ISO 25178-2. Surface roughness measurement experiments with 11 surfaces show that measuring equipment values of mean spacing of profile irregularities in the longitudinal direction are not reliable due to the divergence of surface mean plane and roughness profile mean line. After the additional calculations it was stated that parameter Str can be used for determination of parameter RSm2 and roughness anisotropy evaluation for grinded, polished, friction surfaces and other surfaces with similar characteristics.

  14. Surface properties of beached plastics.

    PubMed

    Fotopoulou, Kalliopi N; Karapanagioti, Hrissi K

    2015-07-01

    Studying plastic characteristics in the marine environment is important to better understand interaction between plastics and the environment. In the present study, high-density polyethylene (HDPE), polyethylene terephalate (PET), and polyvinyl chloride (PVC) samples were collected from the coastal environment in order to study their surface properties. Surface properties such as surface functional groups, surface topography, point of zero charge, and color change are important factors that change during degradation. Eroded HDPE demonstrated an altered surface topography and color and new functional groups. Eroded PET surface was uneven, yellow, and occasionally, colonized by microbes. A decrease in Fourier transform infrared (FTIR) peaks was observed for eroded PET suggesting that degradation had occurred. For eroded PVC, its surface became more lamellar and a new FTIR peak was observed. These surface properties were obtained due to degradation and could be used to explain the interaction between plastics, microbes, and pollutants.

  15. EPA Permeable Surface Research - Poster

    EPA Science Inventory

    EPA recognizes permeable surfaces as an effective post-construction infiltration-based Best Management Practice to mitigate the adverse effects of stormwater runoff. The professional user community conceptually embraces permeable surfaces as a tool for making runoff more closely...

  16. The surface science of nanocrystals

    NASA Astrophysics Data System (ADS)

    Boles, Michael A.; Ling, Daishun; Hyeon, Taeghwan; Talapin, Dmitri V.

    2016-02-01

    All nanomaterials share a common feature of large surface-to-volume ratio, making their surfaces the dominant player in many physical and chemical processes. Surface ligands -- molecules that bind to the surface -- are an essential component of nanomaterial synthesis, processing and application. Understanding the structure and properties of nanoscale interfaces requires an intricate mix of concepts and techniques borrowed from surface science and coordination chemistry. Our Review elaborates these connections and discusses the bonding, electronic structure and chemical transformations at nanomaterial surfaces. We specifically focus on the role of surface ligands in tuning and rationally designing properties of functional nanomaterials. Given their importance for biomedical (imaging, diagnostics and therapeutics) and optoelectronic (light-emitting devices, transistors, solar cells) applications, we end with an assessment of application-targeted surface engineering.

  17. Surfing wavy surfaces: Bacteria-surface interactions in flow

    NASA Astrophysics Data System (ADS)

    Miño, Gastón L.; Kantsler, Vasily; Stocker, Roman

    2014-11-01

    Complex processes occur when microbes interact with surfaces, from mixture enhancement and motion rectification to biofilm formation. Microbe-surface interactions frequently occur in flowing fluids, and flow has recently been shown to have itself unexpected consequences on the dynamics of motile microbes. Here we report on microfluidic experiments in which the interactions of Escherichia coli bacteria with wavy surfaces was quantified in the presence of fluid flow, a model system for naturally occurring topography of many real surfaces. We quantify surface interactions in terms of incident and scattering angles over a range of flow conditions, and compare results to the observations for a microchannel with straight walls.

  18. Chemical enhancement of surface deposition

    DOEpatents

    Patch, K.D.; Morgan, D.T.

    1997-07-29

    A method and apparatus are disclosed for increasing the deposition of ions onto a surface, such as the adsorption of uranium ions on the detecting surface of a radionuclide detector. The method includes the step of exposing the surface to a complexing agent, such as a phosphate ion solution, which has an affinity for the dissolved species to be deposited on the surface. This provides, for example, enhanced sensitivity of the radionuclide detector. 16 figs.

  19. Chemical enhancement of surface deposition

    DOEpatents

    Patch, Keith D.; Morgan, Dean T.

    1997-07-29

    A method and apparatus for increasing the deposition of ions onto a surface, such as the adsorption of uranium ions on the detecting surface of a radionuclide detector. The method includes the step of exposing the surface to a complexing agent, such as a phosphate ion solution, which has an affinity for the dissolved species to be deposited on the surface. This provides, for example, enhanced sensitivity of the radionuclide detector.

  20. Method for lubricating contacting surfaces

    DOEpatents

    Dugger, Michael T [Tijeras, NM; Ohlhausen, James A [Albuquerque, NM; Asay, David B [Boalsburg, PA; Kim, Seong H [State College, PA

    2011-12-06

    A method is provided for tribological lubrication of sliding contact surfaces, where two surfaces are in contact and in motion relative to each other, operating in a vapor-phase environment containing at least one alcohol compound at a concentration sufficiently high to provide one monolayer of coverage on at least one of the surfaces, where the alcohol compound continuously reacts at the surface to provide lubrication.

  1. Flow over riblet curved surfaces

    NASA Astrophysics Data System (ADS)

    Loureiro, J. B. R.; Silva Freire, A. P.

    2011-12-01

    The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).

  2. Surface Characterization Techniques: An Overview

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2002-01-01

    To understand the benefits that surface modifications provide, and ultimately to devise better ones, it is necessary to study the physical, mechanical, and chemical changes they cause. This chapter surveys classical and leading-edge developments in surface structure and property characterization methodologies. The primary emphases are on the use of these techniques as they relate to surface modifications, thin films and coatings, and tribological engineering surfaces and on the implications rather than the instrumentation.

  3. Surface diffraction study of the hydrated hematite (1102) surface.

    SciTech Connect

    Tanwar, K. S.; Lo, C. S.; Eng, P. J.; Catalano, J. G.; Walko, D. A.; Brown, G. E., Jr.; Waychunas, G. A.; Chaka, A. M.; Trainor, T. P.; X-Ray Science Division; Univ. of Alaska Fairbanks; NIST; Univ. of Chicago; Stanford Univ.; LBNL; SSRL

    2007-01-01

    The structure of the hydroxylated {alpha}-Fe{sub 2}O{sub 3(1{bar 1}02)} surface prepared via a wet chemical and mechanical polishing (CMP) procedure was determined using X-ray crystal truncation rod diffraction. The experimentally determined surface model was compared with theoretical structures developed from density functional theory (DFT) calculations to identify the most likely protonation states of the surface (hydr)oxo moieties. The results show that the hydroxylated CMP-prepared surface differs from an ideal stoichiometric termination due to vacancies of the near surface bulk Fe sites. This result differs from previous ultra high vacuum studies where two stable terminations were observed: a stoichiometric (1 x 1) termination and a partially reduced (2 x 1) reconstructed surface. The complementary DFT studies suggest that hydroxylated surfaces are thermodynamically more stable than dehydroxylated surfaces in the presence of water. The results illustrate that the best fit surface model has predominantly three types of (hydr)oxo functional groups exposed at the surface at circumneutral pH: Fe-OH{sub 2}, Fe{sub 2}-OH, and Fe{sub 3}-O and provide a structural basis for interpreting the reactivity of model iron-(hydr)oxide surfaces under aqueous conditions.

  4. Brain surface conformal parameterization using Riemann surface structure.

    PubMed

    Wang, Yalin; Lui, Lok Ming; Gu, Xianfeng; Hayashi, Kiralee M; Chan, Tony F; Toga, Arthur W; Thompson, Paul M; Yau, Shing-Tung

    2007-06-01

    In medical imaging, parameterized 3-D surface models are useful for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. Here we introduce a parameterization method based on Riemann surface structure, which uses a special curvilinear net structure (conformal net) to partition the surface into a set of patches that can each be conformally mapped to a parallelogram. The resulting surface subdivision and the parameterizations of the components are intrinsic and stable (their solutions tend to be smooth functions and the boundary conditions of the Dirichlet problem can be enforced). Conformal parameterization also helps transform partial differential equations (PDEs) that may be defined on 3-D brain surface manifolds to modified PDEs on a two-dimensional parameter domain. Since the Jacobian matrix of a conformal parameterization is diagonal, the modified PDE on the parameter domain is readily solved. To illustrate our techniques, we computed parameterizations for several types of anatomical surfaces in 3-D magnetic resonance imaging scans of the brain, including the cerebral cortex, hippocampi, and lateral ventricles. For surfaces that are topologically homeomorphic to each other and have similar geometrical structures, we show that the parameterization results are consistent and the subdivided surfaces can be matched to each other. Finally, we present an automatic sulcal landmark location algorithm by solving PDEs on cortical surfaces. The landmark detection results are used as constraints for building conformal maps between surfaces that also match explicitly defined landmarks.

  5. Dropwise Condensation of Low Surface Tension Fluids on Omniphobic Surfaces

    PubMed Central

    Rykaczewski, Konrad; Paxson, Adam T.; Staymates, Matthew; Walker, Marlon L.; Sun, Xiaoda; Anand, Sushant; Srinivasan, Siddarth; McKinley, Gareth H.; Chinn, Jeff; Scott, John Henry J.; Varanasi, Kripa K.

    2014-01-01

    Compared to the significant body of work devoted to surface engineering for promoting dropwise condensation heat transfer of steam, much less attention has been dedicated to fluids with lower interfacial tension. A vast array of low-surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants are used in a number of industrial applications, and the development of passive means for increasing their condensation heat transfer coefficients has potential for significant efficiency enhancements. Here we investigate condensation behavior of a variety of liquids with surface tensions in the range of 12 to 28 mN/m on three types of omniphobic surfaces: smooth oleophobic, re-entrant superomniphobic, and lubricant-impregnated surfaces. We demonstrate that although smooth oleophobic and lubricant-impregnated surfaces can promote dropwise condensation of the majority of these fluids, re-entrant omniphobic surfaces became flooded and reverted to filmwise condensation. We also demonstrate that on the lubricant-impregnated surfaces, the choice of lubricant and underlying surface texture play a crucial role in stabilizing the lubricant and reducing pinning of the condensate. With properly engineered surfaces to promote dropwise condensation of low-surface tension fluids, we demonstrate a four to eight-fold improvement in the heat transfer coefficient. PMID:24595171

  6. Brain Surface Conformal Parameterization Using Riemann Surface Structure

    PubMed Central

    Wang, Yalin; Lui, Lok Ming; Gu, Xianfeng; Hayashi, Kiralee M.; Chan, Tony F.; Toga, Arthur W.; Thompson, Paul M.; Yau, Shing-Tung

    2011-01-01

    In medical imaging, parameterized 3-D surface models are useful for anatomical modeling and visualization, statistical comparisons of anatomy, and surface-based registration and signal processing. Here we introduce a parameterization method based on Riemann surface structure, which uses a special curvilinear net structure (conformal net) to partition the surface into a set of patches that can each be conformally mapped to a parallelogram. The resulting surface subdivision and the parameterizations of the components are intrinsic and stable (their solutions tend to be smooth functions and the boundary conditions of the Dirichlet problem can be enforced). Conformal parameterization also helps transform partial differential equations (PDEs) that may be defined on 3-D brain surface manifolds to modified PDEs on a two-dimensional parameter domain. Since the Jacobian matrix of a conformal parameterization is diagonal, the modified PDE on the parameter domain is readily solved. To illustrate our techniques, we computed parameterizations for several types of anatomical surfaces in 3-D magnetic resonance imaging scans of the brain, including the cerebral cortex, hippocampi, and lateral ventricles. For surfaces that are topologically homeomorphic to each other and have similar geometrical structures, we show that the parameterization results are consistent and the subdivided surfaces can be matched to each other. Finally, we present an automatic sulcal landmark location algorithm by solving PDEs on cortical surfaces. The landmark detection results are used as constraints for building conformal maps between surfaces that also match explicitly defined landmarks. PMID:17679336

  7. Dropwise Condensation of Low Surface Tension Fluids on Omniphobic Surfaces

    NASA Astrophysics Data System (ADS)

    Rykaczewski, Konrad; Paxson, Adam T.; Staymates, Matthew; Walker, Marlon L.; Sun, Xiaoda; Anand, Sushant; Srinivasan, Siddarth; McKinley, Gareth H.; Chinn, Jeff; Scott, John Henry J.; Varanasi, Kripa K.

    2014-03-01

    Compared to the significant body of work devoted to surface engineering for promoting dropwise condensation heat transfer of steam, much less attention has been dedicated to fluids with lower interfacial tension. A vast array of low-surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants are used in a number of industrial applications, and the development of passive means for increasing their condensation heat transfer coefficients has potential for significant efficiency enhancements. Here we investigate condensation behavior of a variety of liquids with surface tensions in the range of 12 to 28 mN/m on three types of omniphobic surfaces: smooth oleophobic, re-entrant superomniphobic, and lubricant-impregnated surfaces. We demonstrate that although smooth oleophobic and lubricant-impregnated surfaces can promote dropwise condensation of the majority of these fluids, re-entrant omniphobic surfaces became flooded and reverted to filmwise condensation. We also demonstrate that on the lubricant-impregnated surfaces, the choice of lubricant and underlying surface texture play a crucial role in stabilizing the lubricant and reducing pinning of the condensate. With properly engineered surfaces to promote dropwise condensation of low-surface tension fluids, we demonstrate a four to eight-fold improvement in the heat transfer coefficient.

  8. Interaction between heterogeneously charged surfaces: Surface patches and charge modulation

    NASA Astrophysics Data System (ADS)

    Ben-Yaakov, Dan; Andelman, David; Diamant, Haim

    2013-02-01

    When solid surfaces are immersed in aqueous solutions, some of their charges can dissociate and leave behind charged patches on the surface. Although the charges are distributed heterogeneously on the surface, most of the theoretical models treat them as homogeneous. For overall non-neutral surfaces, the assumption of surface charge homogeneity is rather reasonable since the leading terms of two such interacting surfaces depend on the nonzero average charge. However, for overall neutral surfaces the nature of the surface charge distribution is crucial in determining the intersurface interaction. In the present work we study the interaction between two charged surfaces across an aqueous solution for several charge distributions. The analysis is preformed within the framework of the linearized Poisson-Boltzmann theory. For periodic charge distributions the interaction is found to be repulsive at small separations, unless the two surface distributions are completely out-of-phase with respect to each other. For quenched random charge distributions we find that due to the presence of the ionic solution in between the surfaces, the intersurface repulsion dominates over the attraction in the linear regime of the Poisson-Boltzmann theory. The effect of quenched charge heterogeneity is found to be particularly substantial in the case of large charged domains.

  9. Dropwise condensation of low surface tension fluids on omniphobic surfaces.

    PubMed

    Rykaczewski, Konrad; Paxson, Adam T; Staymates, Matthew; Walker, Marlon L; Sun, Xiaoda; Anand, Sushant; Srinivasan, Siddarth; McKinley, Gareth H; Chinn, Jeff; Scott, John Henry J; Varanasi, Kripa K

    2014-03-05

    Compared to the significant body of work devoted to surface engineering for promoting dropwise condensation heat transfer of steam, much less attention has been dedicated to fluids with lower interfacial tension. A vast array of low-surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants are used in a number of industrial applications, and the development of passive means for increasing their condensation heat transfer coefficients has potential for significant efficiency enhancements. Here we investigate condensation behavior of a variety of liquids with surface tensions in the range of 12 to 28 mN/m on three types of omniphobic surfaces: smooth oleophobic, re-entrant superomniphobic, and lubricant-impregnated surfaces. We demonstrate that although smooth oleophobic and lubricant-impregnated surfaces can promote dropwise condensation of the majority of these fluids, re-entrant omniphobic surfaces became flooded and reverted to filmwise condensation. We also demonstrate that on the lubricant-impregnated surfaces, the choice of lubricant and underlying surface texture play a crucial role in stabilizing the lubricant and reducing pinning of the condensate. With properly engineered surfaces to promote dropwise condensation of low-surface tension fluids, we demonstrate a four to eight-fold improvement in the heat transfer coefficient.

  10. Surfaces. [characterization of surface properties for predicting bond quality

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1983-01-01

    Techniques for the characterization of surface cleanliness and roughness for predicting the quality of an adhesive bond are outlined. Generally, smooth surfaces are only available from cleavage of crystalline materials along a natural cleavage plane. Films must be deposited on metal surfaces to achieve the same smoothness. Once the surfaces are clean, however, reaction with the ambient atmosphere becomes likely through diffusive and absorption processes, producing asperities. Electron diffraction, Auger electron, and X ray emission spectroscopy are used to characterize surface condition. Once the surface is observed to be clean, the application of an adhesive will usually prohibit separation along the adhesive; separation is then confined to the weaker of the two materials. Finally, the use of polytetrafluorothylene adhesive to test the adhesion between polymers and metal surfaces is described.

  11. SDL: A Surface Description Language

    NASA Technical Reports Server (NTRS)

    Maple, Raymond C.

    1992-01-01

    A new interpreted language specifically designed for surface grid generation is introduced. Many unique aspects of the language are discussed, including the farray, vector, curve, and surface data types and the operators used to manipulate them. Custom subroutine libraries written in the language are used to easily build surface grids for generic missile shapes.

  12. Planation surfaces in Northern Ethiopia

    NASA Astrophysics Data System (ADS)

    Coltorti, M.; Dramis, F.; Ollier, C. D.

    2007-09-01

    Planation surfaces are an old-fashioned topic in geomorphology, but they are nevertheless important where they make up much of the landscape. Northern Ethiopia is largely a stepped topography, caused by differential erosion. Exhumation of old planation surfaces that were preserved under sedimentary or volcanic cover is an important process in landscape evolution. The oldest planation surface is of early Palaeozoic age (PS1); the second is Late Triassic (PS2); and the third is of Early Cretaceous age (PS3). The Oligocene Trap Volcanics buried a surface (PS4) of early Tertiary age, which is now widely exposed by erosion as a surface that, where flat enough, is an exhumed planation surface. The surfaces do not relate to the supposed Africa-wide pediplain sequence of King [King, L.C., 1975. Planation surfaces upon highlands. Z. Geomorph. NF 20 (2), 133-148.], either in mode of formation and age. Although the region is tropical, there is scarce evidence of deep weathering and few indications that the surfaces could be regarded as etchplains. These surfaces indicate that eastern Africa underwent long episodes of tectonic quiescence during which erosion processes were able to planate the surface at altitudes not too far from sea level. Only after the onset of rifting processes, uplift became active and transformed a vast lowland plain into the present Ethiopian highlands, largely exceeding 2500 m a.s.l. Some hypotheses and speculations on the genesis of these surfaces are considered here.

  13. Surface chemical modification of nanocrystals

    DOEpatents

    Helms, Brett Anthony; Milliron, Delia Jane; Rosen, Evelyn Louise; Buonsanti, Raffaella; Llordes, Anna

    2017-03-14

    Nanocrystals comprising organic ligands at surfaces of the plurality of nanocrystals are provided. The organic ligands are removed from the surfaces of the nanocrystals using a solution comprising a trialkyloxonium salt in a polar aprotic solvent. The removal of the organic ligands causes the nanocrystals to become naked nanocrystals with cationic surfaces.

  14. Surface properties of HMX crystal

    NASA Technical Reports Server (NTRS)

    Yee, R. Y.; Adicoff, A.; Dibble, E. J.

    1980-01-01

    The surface properties of Beta-HMX crystals were studied. The surface energies of three principal crystal faces were obtained by measuring contact angles with several reference liquids. The surface energies and polarity of the three crystal faces are found to be different.

  15. Armor Plate Surface Roughness Measurements

    DTIC Science & Technology

    2005-04-01

    Armor Plate Surface Roughness Measurements by Brian Stanton, William Coburn, and Thomas J. Pizzillo ARL-TR-3498 April 2005... Armor Plate Surface Roughness Measurements Brian Stanton, William Coburn and Thomas J. Pizzillo Sensors and Electron Devices Directorate...October 2004 5a. CONTRACT NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Armor Plate Surface Roughness Measurements 5c. PROGRAM ELEMENT NUMBER

  16. Plasma surface modification of polymers

    NASA Technical Reports Server (NTRS)

    Hirotsu, T.

    1980-01-01

    Thin plasma polymerization films are discussed from the viewpoint of simplicity in production stages. The application of selective, absorbent films and films used in selective permeability was tested. The types of surface modification of polymers discussed are: (1) plasma etching, (2) surface coating by plasma polymerized thin films, and (3) plasma activation surface graft polymerization.

  17. Desulfurization chemistry on tungsten surfaces

    SciTech Connect

    Benziger, J.B.; Preston, R.E.

    1985-01-01

    Desulfurization on tungsten surfaces was studied by Auger spectroscopy, temperature programmed desorption, and infrared spectroscopy. Aliphatic compounds reacted by electrophilic interaction of sulfur with the surface. On sulfided surfaces adsorption occurred by disulfide linkages, but C-S bond scission required vacant metal sites. Thiophene underwent electrophilic attack on the ring at the ..cap alpha..-carbon by metal sites.

  18. [Graphic reconstruction of anatomic surfaces].

    PubMed

    Ciobanu, O

    2004-01-01

    The paper deals with the graphic reconstruction of anatomic surfaces in a virtual 3D setting. Scanning technologies and soft provides a greater flexibility in the digitization of surfaces and a higher resolution and accuracy. An alternative cheap method for the reconstruction of 3D anatomic surfaces is presented in connection with some studies and international projects developed by Medical Design research team.

  19. Bibliography of the lunar surface

    USGS Publications Warehouse

    Freeberg, Jacquelyn H.

    1970-01-01

    The term "surface" in this bibliography is defined to include landforms and surface materials and the nature of, and processes responsible for, their physical characteristics. References are divided into two listings: (1) Surface features and materials; and (2) Telescopic observations. The former is accompanied by a subject index, the latter by a locality index.

  20. Open surface flotation method

    SciTech Connect

    Bass, D.M.; Wang, F.

    1981-11-24

    A method for the in situ separation of viscous crude oil from a reservoir such as, oil sand, or tar sand is disclosed. Hot water is introduced to the top surface of the reservoir while steam is injected into the reservoir through drill holes. The hot water and steam may contain a surfactant. The bouyancy of the crude oil creates an artificial water drive which causes the water and oil to ''flip-flop'' so that the oil rises to the top of the reservoir and separates from the remainder of the reservoir material. If the overburden is deep, underground mining techniques may be used to reach the reservoir prior to applying the present method.

  1. Mars Surface Habitability Options

    NASA Technical Reports Server (NTRS)

    Howe, A. Scott; Simon, Matthew; Smitherman, David; Howard, Robert; Toups, Larry; Hoffman, Stephen J.

    2015-01-01

    This paper reports on current habitability concepts for an Evolvable Mars Campaign (EMC) prepared by the NASA Human Spaceflight Architecture Team (HAT). For many years NASA has investigated alternative human Mars missions, examining different mission objectives, trajectories, vehicles, and technologies; the combinations of which have been referred to as reference missions or architectures. At the highest levels, decisions regarding the timing and objectives for a human mission to Mars continue to evolve while at the lowest levels, applicable technologies continue to advance. This results in an on-going need for assessments of alternative system designs such as the habitat, a significant element in any human Mars mission scenario, to provide meaningful design sensitivity characterizations to assist decision-makers regarding timing, objectives, and technologies. As a subset of the Evolvable Mars Campaign activities, the habitability team builds upon results from past studies and recommends options for Mars surface habitability compatible with updated technologies.

  2. Bacterial surface adaptation

    NASA Astrophysics Data System (ADS)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  3. Extraterrestrial surface propulsion systems

    NASA Astrophysics Data System (ADS)

    Ash, Robert L.; Blackstock, Dexter L.; Barnhouse, K.; Charalambous, Z.; Coats, J.; Danagan, J.; Davis, T.; Dickens, J.; Harris, P.; Horner, G.

    Lunar traction systems, Mars oxygen production, and Mars methane engine operation were the three topics studied during 1992. An elastic loop track system for lunar construction operations was redesigned and is being tested. A great deal of work on simulating the lunar environment to facilitate traction testing has been reported. Operation of an oxygen processor under vacuum conditions has been the focus of another design team. They have redesigned the processor facility. This included improved seals and heat shields. Assuming methane and oxygen can be produced from surface resources on Mars, a third design team has addressed the problem of using Mars atmospheric carbon dioxide to control combustion temperatures in an internal combustion engine. That team has identified appropriate tests and instrumentation. They have reported on the test rig that they designed and the computer-based system for acquiring data.

  4. Crystallography on Curved Surfaces

    NASA Astrophysics Data System (ADS)

    Vitelli, Vincenzo; Lucks, Julius; Nelson, David

    2007-03-01

    We present a theoretical and numerical study of the static and dynamical properties that distinguish two dimensional curved crystals from their flat space counterparts. Experimental realizations include block copolymer mono-layers on lithographically patterned substrates and self-assembled colloidal particles on a curved interface. At the heart of our approach lies a simple observation: the packing of interacting spheres constrained to lie on a curved surface is necessarily frustrated even in the absence of defects. As a result, whenever lattice imperfections or topological defects are introduced in the curved crystal they couple to the pre-stress of geometric frustration giving rise to elastic potentials. These geometric potentials are non-local functions of the Gaussian curvature and depend on the position of the defects. They play an important role in stress relaxation dynamics, elastic instabilities and melting.

  5. Tunable surface plasmon devices

    DOEpatents

    Shaner, Eric A [Rio Rancho, NM; Wasserman, Daniel [Lowell, MA

    2011-08-30

    A tunable extraordinary optical transmission (EOT) device wherein the tunability derives from controlled variation of the dielectric constant of a semiconducting material (semiconductor) in evanescent-field contact with a metallic array of sub-wavelength apertures. The surface plasmon resonance wavelength can be changed by changing the dielectric constant of the dielectric material. In embodiments of this invention, the dielectric material is a semiconducting material. The dielectric constant of the semiconducting material in the metal/semiconductor interfacial region is controllably adjusted by adjusting one or more of the semiconductor plasma frequency, the concentration and effective mass of free carriers, and the background high-frequency dielectric constant in the interfacial region. Thermal heating and/or voltage-gated carrier-concentration changes may be used to variably adjust the value of the semiconductor dielectric constant.

  6. Surface code quantum communication.

    PubMed

    Fowler, Austin G; Wang, David S; Hill, Charles D; Ladd, Thaddeus D; Van Meter, Rodney; Hollenberg, Lloyd C L

    2010-05-07

    Quantum communication typically involves a linear chain of repeater stations, each capable of reliable local quantum computation and connected to their nearest neighbors by unreliable communication links. The communication rate of existing protocols is low as two-way classical communication is used. By using a surface code across the repeater chain and generating Bell pairs between neighboring stations with probability of heralded success greater than 0.65 and fidelity greater than 0.96, we show that two-way communication can be avoided and quantum information can be sent over arbitrary distances with arbitrarily low error at a rate limited only by the local gate speed. This is achieved by using the unreliable Bell pairs to measure nonlocal stabilizers and feeding heralded failure information into post-transmission error correction. Our scheme also applies when the probability of heralded success is arbitrarily low.

  7. Extraterrestrial surface propulsion systems

    NASA Technical Reports Server (NTRS)

    Ash, Robert L.; Blackstock, Dexter L.; Barnhouse, K.; Charalambous, Z.; Coats, J.; Danagan, J.; Davis, T.; Dickens, J.; Harris, P.; Horner, G.

    1992-01-01

    Lunar traction systems, Mars oxygen production, and Mars methane engine operation were the three topics studied during 1992. An elastic loop track system for lunar construction operations was redesigned and is being tested. A great deal of work on simulating the lunar environment to facilitate traction testing has been reported. Operation of an oxygen processor under vacuum conditions has been the focus of another design team. They have redesigned the processor facility. This included improved seals and heat shields. Assuming methane and oxygen can be produced from surface resources on Mars, a third design team has addressed the problem of using Mars atmospheric carbon dioxide to control combustion temperatures in an internal combustion engine. That team has identified appropriate tests and instrumentation. They have reported on the test rig that they designed and the computer-based system for acquiring data.

  8. Methane: A Menace Surfaces

    NASA Astrophysics Data System (ADS)

    Anthony, Katey Walter

    2011-11-01

    The arctic permafrost is thawing, releasing organic matter that was frozen in the ground into the bottoms of lakes. This organic matter feeds microbes that produce methane, which in turn escapes to the atmosphere. Permafrost, a rich source of organic carbon, covers 20% of the earth's land surface, and one third to one half of permafrost is now within 1.0 ° C to 3 ° C of thawing. New estimates indicate that by 2100, thawing permafrost could boost emissions of methane—a greenhouse gas that's 25 times more potent than carbon dioxide—by 20 to 40 percent beyond what would be produced by all natural and man-made sources. As a result, the earth's mean annual temperature could rise by an additional 0.32 ° C, further upsetting weather patterns and sea level.

  9. Broadband frequency selective surface

    NASA Astrophysics Data System (ADS)

    Palma, D. A.; Wong, W. C.

    A method for designing broadband dichroic surfaces is described. A tripole and a Jerusalem cross are evaluated as candidate resonant elements. The effects of dielectric substrates on resonant frequency and bandwidth are investigated. The theoretical and measured frequency responses of tripoles and Jerusalem crosses are presented. It is observed that the metallic area of the tripole within a given period increases the bandwidth, the maximum theoretical bandwidth of the tripole dichroic sheet being about 50 percent; for a Jerusalem cross, increasing the metallic area of the two perpendicular strips and increasing the end cap capacitative loading increases the bandwidth to a theoretical maximum about 60 percent. Multilayered dichroic panels capable of producing a 4:1 stopband and 1.4:1 band separation have been designed for circular polarization and angles of incidence up to 40 degrees.

  10. Mars Surface Habitability Options

    NASA Technical Reports Server (NTRS)

    Howe, A. Scott; Simon, Matthew; Smitherman, David; Howard, Robert; Toups, Larry; Hoffman, Stephen J.

    2015-01-01

    This paper reports on current habitability concepts for an Evolvable Mars Campaign (EMC) prepared by the NASA Human Spaceflight Architecture Team (HAT). For many years NASA has investigated alternative human Mars missions, examining different mission objectives, trajectories, vehicles, and technologies; the combinations of which have been referred to as reference missions or architectures. At the highest levels, decisions regarding the timing and objectives for a human mission to Mars continue to evolve while at the lowest levels, applicable technologies continue to advance. This results in an on-going need for assessments of alternative system designs such as the habitat, a significant element in any human Mars mission scenario, to provide meaningful design sensitivity characterizations to assist decision-makers regarding timing, objectives, and technologies. As a subset of the Evolvable Mars Campaign activities, the habitability team builds upon results from past studies and recommends options for Mars surface habitability compatible with updated technologies.

  11. Surface Temperature Data Analysis

    NASA Technical Reports Server (NTRS)

    Hansen, James; Ruedy, Reto

    2012-01-01

    Small global mean temperature changes may have significant to disastrous consequences for the Earth's climate if they persist for an extended period. Obtaining global means from local weather reports is hampered by the uneven spatial distribution of the reliably reporting weather stations. Methods had to be developed that minimize as far as possible the impact of that situation. This software is a method of combining temperature data of individual stations to obtain a global mean trend, overcoming/estimating the uncertainty introduced by the spatial and temporal gaps in the available data. Useful estimates were obtained by the introduction of a special grid, subdividing the Earth's surface into 8,000 equal-area boxes, using the existing data to create virtual stations at the center of each of these boxes, and combining temperature anomalies (after assessing the radius of high correlation) rather than temperatures.

  12. Reusable Surface Insulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Advanced Flexible Reusable Surface Insulation, developed by Ames Research Center, protects the Space Shuttle from the searing heat that engulfs it on reentry into the Earth's atmosphere. Initially integrated into the Space Shuttle by Rockwell International, production was transferred to Hi-Temp Insulation Inc. in 1974. Over the years, Hi-Temp has created many new technologies to meet the requirements of the Space Shuttle program. This expertise is also used commercially, including insulation blankets to cover aircrafts parts, fire barrier material to protect aircraft engine cowlings and aircraft rescue fire fighter suits. A Fire Protection Division has also been established, offering the first suit designed exclusively by and for aircraft rescue fire fighters. Hi-Temp is a supplier to the Los Angeles City Fire Department as well as other major U.S. civil and military fire departments.

  13. Surface electromyogram signal modelling.

    PubMed

    McGill, K C

    2004-07-01

    The paper reviews the fundamental components of stochastic and motor-unit-based models of the surface electromyogram (SEMG). Stochastic models used in ergonomics and kinesiology consider the SEMG to be a stochastic process whose amplitude is related to the level of muscle activation and whose power spectral density reflects muscle conduction velocity. Motor-unit-based models for describing the spatio-temporal distribution of individual motor-unit action potentials throughout the limb are quite robust, making it possible to extract precise information about motor-unit architecture from SEMG signals recorded by multi-electrode arrays. Motor-unit-based models have not yet been proven as successful, however, for extracting information about recruitment and firing rates throughout the full range of contraction. The relationship between SEMG and force during natural dynamic movements is much too complex to model in terms of single motor units.

  14. Where's the Surface?

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02182 Where's the Surface?

    In this image the martian surface is completely hidden from view by thick clouds. The thickness of the clouds indicates the dust is a major component of the clouds. Images like this one can provide vital information about the atmosphere and climate of Mars today. This image was collected during late summer near the south pole.

    Image information: VIS instrument. Latitude -69.9N, Longitude 235.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Laser heterodyne surface profiler

    DOEpatents

    Sommargren, G.E.

    1984-06-26

    Method and apparatus are disclosed for testing the deviation of the face of an object from a flat smooth surface using a laser beam having two plane-polarized components, one of a frequency greater than the other to produce a difference frequency with a phase to be used as a reference. The beam also is split into its two components which are directed onto spaced apart points on the face of the object. The object is rotated on an axis coincident with one component as a reference. The other component follows a circular track on the face of the object as the object is rotated. The two components are recombined after reflection to produce a difference frequency having a phase that is shifted in an amount that is proportional to the difference in path length as compared to the reference phase to produce an electrical output signal proportional to the deviation of the height of the surface along the circular track. The output signal is generated by means of a phase detector that includes a first photodetector in the path of the recombined components and a second photodetector in the path of the reference phase. The output signal is dependent on the phase difference of the two photodetector signals. A polarizer, a quarter-wave plate and a half-wave plate are in series in the path of the reference phase. Rotation of the half-wave plate can be used for phase adjustment over a full 360[degree] range for initial calibration of the apparatus. 12 figs.

  16. Where's the Surface?

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02182 Where's the Surface?

    In this image the martian surface is completely hidden from view by thick clouds. The thickness of the clouds indicates the dust is a major component of the clouds. Images like this one can provide vital information about the atmosphere and climate of Mars today. This image was collected during late summer near the south pole.

    Image information: VIS instrument. Latitude -69.9N, Longitude 235.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. The surface learned from nature

    NASA Astrophysics Data System (ADS)

    Lim, H.; Kim, W. D.

    2010-07-01

    In this work, I would like to introduce the emerging surface of nature. The surface in nature, has the multi and optimized function with well organized structure. There are so many examples that we learn and apply to technology. First example is self-cleaning surface. Some plants (such as lotus leaf, taro leaf) and the wings of many large-winged insects (such as moth, butterfly, dragonfly) remain their surface clean in the very dirty environment. This self cleaning effect is accomplished by the superhydrophobic surfaces which exhibit the water contact angle of more than 150° with low sliding angle. Generally, the superhydrophobic surface is made up the two factors. One is the surface composition having the low surface tension energy. The other is the surface morphology of hierarchical structure of micro and nano size. Because almost nature surface have the hierarchical structures range from macro to nano size, their topography strength their function to adjust the life in nature environment. The other example is the surface to use for drag reduction. The skin friction drag causes eruptions of air or water resulting in greater drag as the speed is increased. This drag requires more energy to overcome. The shark skin having the fine sharp-edged grooves about 0.1 mm wide known riblet reduces in skin friction drag by being far away the vortex. Among a lot of fuctional surface, the most exciting surface the back of stenocara a kind of desert beetles. Stenocara use the micrometre-sized patterns of hydrophobic, wax-coated and hydrophilic, non-waxy regions on their backs to capture water from fog. This fog-collecting structure improves the water collection of fog-capture film, condenser, engine, and future building. Here, the efforts to realize these emerging functional surfaces in nature on technology are reported with the fabrication method and their properties, especially for the control of surface wettability.

  18. Sample-Based Surface Coloring

    PubMed Central

    Bürger, Kai; Krüger, Jens; Westermann, Rüdiger

    2011-01-01

    In this paper, we present a sample-based approach for surface coloring, which is independent of the original surface resolution and representation. To achieve this, we introduce the Orthogonal Fragment Buffer (OFB)—an extension of the Layered Depth Cube—as a high-resolution view-independent surface representation. The OFB is a data structure that stores surface samples at a nearly uniform distribution over the surface, and it is specifically designed to support efficient random read/write access to these samples. The data access operations have a complexity that is logarithmic in the depth complexity of the surface. Thus, compared to data access operations in tree data structures like octrees, data-dependent memory access patterns are greatly reduced. Due to the particular sampling strategy that is employed to generate an OFB, it also maintains sample coherence, and thus, exhibits very good spatial access locality. Therefore, OFB-based surface coloring performs significantly faster than sample-based approaches using tree structures. In addition, since in an OFB, the surface samples are internally stored in uniform 2D grids, OFB-based surface coloring can efficiently be realized on the GPU to enable interactive coloring of high-resolution surfaces. On the OFB, we introduce novel algorithms for color painting using volumetric and surface-aligned brushes, and we present new approaches for particle-based color advection along surfaces in real time. Due to the intermediate surface representation we choose, our method can be used to color polygonal surfaces as well as any other type of surface that can be sampled. PMID:20616392

  19. Sample-based surface coloring.

    PubMed

    Bürger, Kai; Krüger, Jens; Westermann, Rüdiger

    2010-01-01

    In this paper, we present a sample-based approach for surface coloring, which is independent of the original surface resolution and representation. To achieve this, we introduce the Orthogonal Fragment Buffer (OFB)-an extension of the Layered Depth Cube-as a high-resolution view-independent surface representation. The OFB is a data structure that stores surface samples at a nearly uniform distribution over the surface, and it is specifically designed to support efficient random read/write access to these samples. The data access operations have a complexity that is logarithmic in the depth complexity of the surface. Thus, compared to data access operations in tree data structures like octrees, data-dependent memory access patterns are greatly reduced. Due to the particular sampling strategy that is employed to generate an OFB, it also maintains sample coherence, and thus, exhibits very good spatial access locality. Therefore, OFB-based surface coloring performs significantly faster than sample-based approaches using tree structures. In addition, since in an OFB, the surface samples are internally stored in uniform 2D grids, OFB-based surface coloring can efficiently be realized on the GPU to enable interactive coloring of high-resolution surfaces. On the OFB, we introduce novel algorithms for color painting using volumetric and surface-aligned brushes, and we present new approaches for particle-based color advection along surfaces in real time. Due to the intermediate surface representation we choose, our method can be used to color polygonal surfaces as well as any other type of surface that can be sampled.

  20. Tools for measuring surface cleanliness

    DOEpatents

    Schroder, Mark Stewart; Woodmansee, Donald Ernest; Beadie, Douglas Frank

    2002-01-01

    A procedure and tools for quantifying surface cleanliness are described. Cleanliness of a target surface is quantified by wiping a prescribed area of the surface with a flexible, bright white cloth swatch, preferably mounted on a special tool. The cloth picks up a substantial amount of any particulate surface contamination. The amount of contamination is determined by measuring the reflectivity loss of the cloth before and after wiping on the contaminated system and comparing that loss to a previous calibration with similar contamination. In the alternative, a visual comparison of the contaminated cloth to a contamination key provides an indication of the surface cleanliness.

  1. Water on a Hydrophobic surface

    NASA Astrophysics Data System (ADS)

    Scruggs, Ryan; Zhu, Mengjue; Poynor, Adele

    2012-02-01

    Hydrophobicity, meaning literally fear of water, is exhibited on the surfaces of non-stick cooking pans and water resistant clothing, on the leaves of the lotus plan, or even during the protein folding process in our bodies. Hydrophobicity is directly measured by determining a contact angle between water and an objects surface. Associated with a hydrophobic surface is the depletion layer, a low density region approximately 0.2 nm thick. We study this region by comparing data found in lab using surface plasmon resonance techniques to theoretical calculations. Experiments use gold slides coated in ODT and Mercapto solutions to model both hydrophobic and hydrophilic surfaces respectively.

  2. Automated Telerobotic Inspection Of Surfaces

    NASA Technical Reports Server (NTRS)

    Balaram, J.; Prasad, K. Venkatesh

    1996-01-01

    Method of automated telerobotic inspection of surfaces undergoing development. Apparatus implementing method includes video camera that scans over surfaces to be inspected, in manner of mine detector. Images of surfaces compared with reference images to detect flaws. Developed for inspecting external structures of Space Station Freedom for damage from micrometeorites and debris from prior artificial satellites. On Earth, applied to inspection for damage, missing parts, contamination, and/or corrosion on interior surfaces of pipes or exterior surfaces of bridges, towers, aircraft, and ships.

  3. Surface-stabilized gold nanocatalysts

    DOEpatents

    Dai, Sheng [Knoxville, TN; Yan, Wenfu [Oak Ridge, TN

    2009-12-08

    A surface-stabilized gold nanocatalyst includes a solid support having stabilizing surfaces for supporting gold nanoparticles, and a plurality of gold nanoparticles having an average particle size of less than 8 nm disposed on the stabilizing surfaces. The surface-stabilized gold nanocatalyst provides enhanced stability, such as at high temperature under oxygen containing environments. In one embodiment, the solid support is a multi-layer support comprising at least a first layer having a second layer providing the stabilizing surfaces disposed thereon, the first and second layer being chemically distinct.

  4. Laser surface texturing of tool steel: textured surfaces quality evaluation

    NASA Astrophysics Data System (ADS)

    Šugár, Peter; Šugárová, Jana; Frnčík, Martin

    2016-05-01

    In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

  5. Superhydrophobic surfaces fabricated by surface modification of alumina particles

    NASA Astrophysics Data System (ADS)

    Richard, Edna; Aruna, S. T.; Basu, Bharathibai J.

    2012-10-01

    The fabrication of superhydrophobic surfaces has attracted intense interest because of their widespread potential applications in various industrial fields. Recently, some attempts have been carried out to prepare superhydrophobic surfaces using metal oxide nanoparticles. In the present work, superhydrophobic surfaces were fabricated with low surface energy material on alumina particles with different sizes. It was found that particle size of alumina is an important factor in achieving stable superhydrophobic surface. It was possible to obtain alumina surface with water contact angle (WCA) of 156° and a sliding angle of <2°. Superhydrophobicity of the modified alumina is attributed to the combined effect of the micro-nanostructure and low surface energy of fatty acid on the surface. The surface morphology of the alumina powder and coatings was determined by FESEM. The stability of the coatings was assessed by conducting water immersion test. Effect of heat treatment on WCA of the coating was also studied. The transition of alumina from hydrophilic to superhydrophobic state was explained using Wenzel and Cassie models. The method is shown to have potential application for creating superhydrophobic surface on cotton fabrics.

  6. Topics in theoretical surface science

    SciTech Connect

    Todd, R.

    1991-10-25

    The energetics and structures of clean and adsorbate covered surfaces are investigated in this dissertation. First, the formalism, within the Corrected Effective Medium (CEM) method, for calculating the surface energy of a clean surface is derived. The surface energies for many different metals and their low index surfaces are presented. The minimization of the surface energy is then used to predict the multilayer relaxation of the Al(111), (100), Ni(100), (110) and Fe(100) surfaces. Extensions of the surface CEM formalism to calculate the binding energies of ordered adsorbates on metals surfaces are also derived. The minimization of the binding energy allowed determination of the binding heights, sites and the extent of induced multilayer relaxation for H and N atoms on the Fe(110), (100) and W(110) surfaces. The last topic deals with the dynamics of the epitaxial growth of metals on metal surfaces. The CEM method was first modified by making approximations to enable faster evaluations of the potential and its corresponding forces for molecular dynamics simulations. The goal of these simulations was to identify the important steps in the formation of equilibrium epitaxial structures. 180 refs., 31 figs., 18 tabs.

  7. Surface melting of electronic order.

    SciTech Connect

    Wilkins, S. B.; Liu, X.; Wakabayashi, Y.; Kim, J.-W.; Ryan, P. J.; Mitchell, J. F.; Hill, J. P.

    2011-01-01

    We report temperature-dependent surface x-ray scattering studies of the orbital ordered surface in La{sub 0.5}Sr{sub 1.5}MnO{sub 4}. We find that as the bulk ordering temperature is approached from below the thickness of the interface between the electronically ordered and electronically disordered regions at the surface grows, though the bulk correlation length remains unchanged. Close to the transition, the surface is so rough that there is no well-defined electronic surface, despite the presence of bulk electronic order. That is, the electronic ordering at the surface has melted. Above the bulk transition, long-range ordering in the bulk is destroyed but finite-sized isotropic fluctuations persist, with a correlation length roughly equal to that of the low-temperature in-plane surface correlation length.

  8. Does surface roughness amplify wetting?

    SciTech Connect

    Malijevský, Alexandr

    2014-11-14

    Any solid surface is intrinsically rough on the microscopic scale. In this paper, we study the effect of this roughness on the wetting properties of hydrophilic substrates. Macroscopic arguments, such as those leading to the well-known Wenzel's law, predict that surface roughness should amplify the wetting properties of such adsorbents. We use a fundamental measure density functional theory to demonstrate the opposite effect from roughness for microscopically corrugated surfaces, i.e., wetting is hindered. Based on three independent analyses we show that microscopic surface corrugation increases the wetting temperature or even makes the surface hydrophobic. Since for macroscopically corrugated surfaces the solid texture does indeed amplify wetting there must exist a crossover between two length-scale regimes that are distinguished by opposite response on surface roughening. This demonstrates how deceptive can be efforts to extend the thermodynamical laws beyond their macroscopic territory.

  9. Diffusion on ruffled membrane surfaces.

    PubMed

    Naji, Ali; Brown, Frank L H

    2007-06-21

    We present a position Langevin equation for overdamped particle motion on rough two-dimensional surfaces. A Brownian dynamics algorithm is suggested to evolve this equation numerically, allowing for the prediction of effective (projected) diffusion coefficients over corrugated surfaces. In the case of static surface roughness, we find that a simple area-scaling prediction for the projected diffusion coefficient leads to seemingly quantitative agreement with numerical results. To study the effect of dynamic surface evolution on the diffusive process, we consider particle diffusion over a thermally fluctuating elastic membrane. Surface fluctuation has the effect of increasing the effective diffusivity toward a limiting annealed-surface value discussed previously. We argue that protein motion over cell surfaces spans a variety of physical regimes, making it impossible to identify a single approximation scheme appropriate to all measurements of interest.

  10. Surface-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Stiles, Paul L.; Dieringer, Jon A.; Shah, Nilam C.; van Duyne, Richard P.

    2008-07-01

    The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

  11. Yield surfaces for anisotropic plates

    NASA Astrophysics Data System (ADS)

    Walker, J. D.; Thacker, B. H.

    2000-04-01

    Aerospace systems are incorporating composite materials into their structures. The composite materials are often anisotropic in mechanical response due to their geometric layout. For many years, the failure surfaces of anisotropic materials were thought to be characterizable by a quadratic function in the stress, referred to as a Tsai-Wu yield surface, or, in a more restrictive form, a Tsai-Hill yield surface. Such a representation does not work for materials that are strong in two directions and weak in one direction, which is the case of most interest since it represents fiber/epoxy composite plates. This paper demonstrates the impossibility of modeling the failure surface with either the Tsai-Wu or Tsai-Hill failure surfaces. A yield surface is presented based on the lemniscate, which is quartic in the stress. This new yield surface addresses the case of strong in two directions and weak in one.

  12. Anti-fouling bioactive surfaces.

    PubMed

    Yu, Qian; Zhang, Yanxia; Wang, Hongwei; Brash, John; Chen, Hong

    2011-04-01

    Bioactive surfaces refer to surfaces with immobilized bioactive molecules aimed specifically at promoting or supporting particular interactions. Such surfaces are of great importance for various biomedical and biomaterials applications. In the past few years, considerable effort has been made to create bioactive surfaces by forming specific biomolecule-modified surfaces on a non-biofouling "base" or "background". Hydrophilic and bioinert polymers have been widely used as anti-fouling layers that resist non-specific protein interactions. They can also serve as "spacers" to effectively move the immobilized biomolecule away from the surface, thus enhancing its bioactivity. In this review we summarize several successful approaches for the design and preparation of bioactive surfaces based on different types of anti-fouling/spacer materials. Some perspectives on future research in this area are also presented.

  13. Dynamic electrowetting on microstructured surfaces

    NASA Astrophysics Data System (ADS)

    Nita, Satoshi; Wang, Jiayu; Do-Quang, Minh; Chen, Yu-Chung; Suzuki, Yuji; Amberg, Gustav; Shiomi, Junichiro

    2015-11-01

    Surface modification such as surface charging or microstructuring has been shown as an effective method to control static wetting, but its influence on dynamic wetting is still unclear. Previously, we found that the initial stage of droplet spreading can be significantly hindered by surface microstructures, while previous experiments showed that the effect of surface charge on dynamic wetting on a flat surface is minor. Here, we combine microstructuring and electrowetting to further enhance the controllability of the dynamic wetting. Microstructures are fabricated on silicon wafers and the spontaneous spreading of a droplet is imaged with a high-speed camera. We reveal that the spreading rate sensitivity to surface charge increases in the presence of microstructures. Furthermore, numerical simulations solving Cahn-Hilliard/Navier-Stokes equations are performed and the effect of surface modification is quantified in terms of the contact-line friction. This work was financially supported in part by the Japan Science and Technology Agency through CREST.

  14. Mars Surface Simulations

    NASA Astrophysics Data System (ADS)

    Nørnberg, Per; Merrison, Jonathan P.; Gunnlaugsson, Haraldur P.

    2010-05-01

    Laboratory simulations of the Martian surface are of importance to broaden scientific understanding of the physical processes, but also in order to develop the technology necessary for exploration of the planet. The Mars Simulation Laboratory at Aarhus University [1] has been involved in such simulations for around ten years and has developed several experimental facilities for carrying out science or instrument testing under conditions similar to those at the Martian surface, specifically low pressure, low temperature and importantly recreating the wind flow environment and dust suspension (reproducing the Martian dusty aerosol) using Mars analogue material [2]. The science involved in this simulation work has covered a broad spectrum including, erosion induced mineralogy/chemistry, particulate electrification, magnetic properties of Martian dust, biological survival, UV induced chemistry/mineralogy (using a solar simulator), adhesion/cohesion processes and the wind driven transport of dust and sand [3,4]. With regard to technology the wind tunnel facilities have been used in the development of the latest wind and dust sensing instrumentation [5,6]. With support from the European Space Agency (ESA) and Danish national funding an advanced Mars simulation facility has recently been constructed (2009). This wind tunnel facility has a cross section of 2 x 1 m and a length of 8 m, a temperature range down to below -120C, wind speeds in excess of 20m/s, and automated dust control. With a range of (specialised) sensing instrumentation it provides the opportunity to perform a new generation of scientific experiments and allow testing and technology development in the most realistic and rigorous environment. As well as being available for the space agencies, this facility will be open to all potential scientific collaborators. Also European planetary scientists may benefit from support through the EU Europlanet FP7 networking programme. For more information on access

  15. Nonadiabatic dynamics at metal surfaces: Independent-electron surface hopping

    NASA Astrophysics Data System (ADS)

    Shenvi, Neil; Roy, Sharani; Tully, John C.

    2009-05-01

    Recent experiments have shown convincing evidence for nonadiabatic energy transfer from adsorbate degrees of freedom to surface electrons during the interaction of molecules with metal surfaces. In this paper, we propose an independent-electron surface hopping algorithm for the simulation of nonadiabatic gas-surface dynamics. The transfer of energy to electron-hole pair excitations of the metal is successfully captured by hops between electronic adiabats. The algorithm is able to account for the creation of multiple electron-hole pairs in the metal due to nonadiabatic transitions. Detailed simulations of the vibrational relaxation of nitric oxide on a gold surface, employing a multistate potential energy surface fit to density functional theory calculations, confirm that our algorithm can capture the underlying physics of the inelastic scattering process.

  16. Wetting failure of hydrophilic surfaces promoted by surface roughness

    PubMed Central

    Zhao, Meng-Hua; Chen, Xiao-Peng; Wang, Qing

    2014-01-01

    Wetting failure is of vital importance to many physical phenomena, such as industrial coating and drop emission. Here we show when and how the surface roughness promotes the destabilization of a moving contact line on a hydrophilic surface. Beyond the balance of the driving force and viscous resistance where a stable wetting interface is sustained, wetting failure occurs and is modified by the roughness of the surface. The promoting effect arises only when the wetting velocity is high enough to create a gas-liquid-solid composite interface in the vicinity of the moving contact line, and it is a function of the intrinsic contact angle and proportion of solid tops. We propose a model to explain splashes of rough solid spheres impacting into liquids. It reveals a novel concept that dynamic wetting on hydrophilic rough surfaces can be similar to that on hydrophobic surfaces, and brings a new way to design surfaces with specific wetting properties. PMID:24948390

  17. Effect of surface temperature on microparticle-surface adhesion

    NASA Astrophysics Data System (ADS)

    Vallabh, Chaitanya Krishna Prasad; Stephens, James D.; Cetinkaya, Cetin

    2015-07-01

    The effect of surface temperature on the adhesion properties of the bond between a substrate and a single micro-particle is investigated in a non-contact/non-invasive manner by monitoring the rolling/rocking motion dynamics of acoustically excited single microparticles. In the current work, a set of experiments were performed to observe the change in the rocking resonance frequency of the particles with the change of surface temperature. At various substrate surface temperature levels, the work-of-adhesion values of the surface-particle bond are evaluated from the resonance frequencies of the rocking motion of a set of microparticles driven by an orthogonal ultrasonic surface acoustic wave field. The dependence of adhesion bonds of a microparticle and the substrate on the surface temperature has been clearly demonstrated by the performed experiments. It was also observed and noted that the relative humidity plays a vital role in the rolling behavior of particles.

  18. Surface charge--induced ordering of the au(111) surface.

    PubMed

    Wang, J; Davenport, A J; Isaacs, H S; Ocko, B M

    1992-03-13

    Synchrotron surface x-ray scattering (SXS) studies have been carried out at the Au(lll)/electrolyte interface to determine the influence of surface charge on the microscopic arrangement of gold surface atoms. At the electrochemical interface, the surface charge density can be continuously varied by controlling the applied potential. The top layer of gold atoms undergoes a reversible phase transition between the (1 x 1) bulk termination and a (23 x radical3) reconstructed phase on changing the electrode potential. In order to differentiate the respective roles of surface charge and adsorbates, studies were carried out in 0.1 M NaF, NaCl, and NaBr solutions. The phase transition occurs at an induced surface charge density of 0.07 +/- 0.02 electron per atom in all three solutions.

  19. Surface phononic graphene.

    PubMed

    Yu, Si-Yuan; Sun, Xiao-Chen; Ni, Xu; Wang, Qing; Yan, Xue-Jun; He, Cheng; Liu, Xiao-Ping; Feng, Liang; Lu, Ming-Hui; Chen, Yan-Feng

    2016-12-01

    Strategic manipulation of wave and particle transport in various media is the key driving force for modern information processing and communication. In a strongly scattering medium, waves and particles exhibit versatile transport characteristics such as localization, tunnelling with exponential decay, ballistic, and diffusion behaviours due to dynamical multiple scattering from strong scatters or impurities. Recent investigations of graphene have offered a unique approach, from a quantum point of view, to design the dispersion of electrons on demand, enabling relativistic massless Dirac quasiparticles, and thus inducing low-loss transport either ballistically or diffusively. Here, we report an experimental demonstration of an artificial phononic graphene tailored for surface phonons on a LiNbO3 integrated platform. The system exhibits Dirac quasiparticle-like transport, that is, pseudo-diffusion at the Dirac point, which gives rise to a thickness-independent temporal beating for transmitted pulses, an analogue of Zitterbewegung effects. The demonstrated fully integrated artificial phononic graphene platform here constitutes a step towards on-chip quantum simulators of graphene and unique monolithic electro-acoustic integrated circuits.

  20. Surface acoustic wave microfluidics

    PubMed Central

    Ding, Xiaoyun; Li, Peng; Lin, Sz-Chin Steven; Stratton, Zackary S.; Nama, Nitesh; Guo, Feng; Slotcavage, Daniel; Mao, Xiaole; Shi, Jinjie; Costanzo, Francesco; Huang, Tony Jun

    2014-01-01

    The recent introduction of surface acoustic wave (SAW) technology onto lab-on-a-chip platforms has opened a new frontier in microfluidics. The advantages provided by such SAW microfluidics are numerous: simple fabrication, high biocompatibility, fast fluid actuation, versatility, compact and inexpensive devices and accessories, contact-free particle manipulation, and compatibility with other microfluidic components. We believe that these advantages enable SAW microfluidics to play a significant role in a variety of applications in biology, chemistry, engineering, and medicine. In this review article, we discuss the theory underpinning SAWs and their interactions with particles and the contacting fluids in which they are suspended. We then review the SAW-enabled microfluidic devices demonstrated to date, starting with devices that accomplish fluid mixing and transport through the use of travelling SAW; we follow that by reviewing the more recent innovations achieved with standing SAW that enable such actions as particle/cell focusing, sorting, and patterning. Finally, we look forward and appraise where the discipline of SAW microfluidics could go next. PMID:23900527