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Sample records for anagallis arvensis surface

  1. Morphogenesis at the inflorescence shoot apex of Anagallis arvensis: surface geometry and growth in comparison with the vegetative shoot

    PubMed Central

    Kwiatkowska, Dorota; Routier-Kierzkowska, Anne-Lise

    2009-01-01

    Quantitative analysis of geometry and surface growth based on the sequential replica method is used to compare morphogenesis at the shoot apex of Anagallis arvensis in the reproductive and vegetative phases of development. Formation of three types of lateral organs takes place at the Anagallis shoot apical meristem (SAM): vegetative leaf primordia are formed during the vegetative phase and leaf-like bracts and flower primordia during the reproductive phase. Although the shapes of all the three types of primordia are very similar during their early developmental stages, areal growth rates and anisotropy of apex surface growth accompanying formation of leaf or bract primordia are profoundly different from those during formation of flower primordia. This provides an example of different modes of de novo formation of a given shape. Moreover, growth accompanying the formation of the boundary between the SAM and flower primordium is entirely different from growth at the adaxial leaf or bract primordium boundary. In the latter, areal growth rates at the future boundary are the lowest of all the apex surface, while in the former they are relatively very high. The direction of maximal growth rate is latitudinal (along the future boundary) in the case of leaf or bract primordium but meridional (across the boundary) in the case of flower. The replica method does not enable direct analysis of growth in the direction perpendicular to the apex surface (anticlinal direction). Nevertheless, the reconstructed surfaces of consecutive replicas taken from an individual apex allow general directions of SAM surface bulging accompanying primordium formation to be recognized. Precise alignment of consecutive reconstructions shows that the direction of initial bulging during the leaf or bract formation is nearly parallel to the shoot axis (upward bulging), while in the case of flower it is perpendicular to the axis (lateral bulging). In future, such 3D reconstructions can be used to assess

  2. 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

  3. Air pollution induced alterations in assimilate partitioning in Anagallis arvensis L

    SciTech Connect

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

    1989-04-01

    The Thermal Power Plant Complex of Kasimpur (Aligarh, UP, India) emits enormous amounts of oxides of sulfur, nitrogen, and carbon as well as particulate matters on consuming 3192 MT of coal/day. These effluents induce significant alterations in carbon allocation in Anagallis arvensis populations. Monthly samples of 10 plants each were collected on random basis at seedling to mature stage from 0.5, 2, 6, 12 and 20 km leeward from the power plant. In oven dried samples, assimilate partitioning was noted to be more severely altered by the air pollutants in the seedling stage. In 2 and 3 months old populations, photosynthate allocation to root and shoot was not altered noticeably. Considerable changes in carbon allocation were noted in 4 mo old mature stage. The carbon allocation to fruit was 3 fold and to seed was about 4 fold greater in the population thriving 20 km away from the source than in those growing in the vicinity of the source. Assimilate partitioning was linearly related to the distance from power plant and the productivity of the populations.

  4. 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.

  5. 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

  6. 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. PMID:26946117

  7. Floral morphogenesis in Anagallis: Scanning-electron-micrograph sequences from individual growing meristems before, during, and after the transition to flowering.

    PubMed

    Green, P B; Havelange, A; Bernier, G

    1991-11-01

    Non-destructive scanning electron microscopy allows one to visualize changing patterns of individual cells during epidermal development in single meristems. Cell growth and division can be followed in parallel with morphogenesis. The method is applied here to the shoot apex of Anagallis arvensis L. before, during, and after floral transition. Phyllotaxis is decussate; photoperiodic induction of the plant leads to the production of a flower in the axil of each leaf. As seen from above, the recently formed oval vegetative dome is bounded on its slightly longer sides by creases of adjacent leaf bases. The rounded ends of the dome are bounded by connecting tissue, horizontal bands of node cells between the opposed leaf bases. The major growth axis runs parallel to the leaf bases. While slow-growing at the dome center, this axis extends at its periphery to form a new leaf above each band of connecting tissue. Connecting tissue then forms between the new leaves and a new dome is defined at 90° to the former. The growth axis then changes by 90°. This is the vegetative cycle. The first observed departure from vegetative growth is that the connecting tissue becomes longer relative to the leaf creases. Presumably because of this, the major growth axis does not change in the usual way. Extension on the dome continues between the older leaves until the axis typically buckles a second time, on each side, to form a second crease parallel to the new leaf-base crease. The tissue between these two creases becomes the flower primordium. The second crease also delimits the side of a new apical dome with the major axis and growth direction altered by 90°. During this inflorescence cycle the connecting tissue is relatively longer than before. Much activity is common to both cycles. It is concluded that the complex geometrical features of the inflorescence cycle may result from a change in a biophysical boundary condition involving dome geometry, rather than a comprehensive revision

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. First report of leaf spot of Convolvulus arvensis caused by Phoma macrostoma var. macrostoma in Turkey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field bindweed (Convolvulus arvensis L.) is an exotic perennial vine that is invasive in the USA and problematic in Turkey. In May 2012, diseased Convolvulus arvensis plants were found near Ondokuz Mayis University, Samsun, Turkey. Symptoms were irregular tan-colored necrotic lesions on leaves. Leav...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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....

  11. Dormancy in Seeds of Charlock (Sinapis arvensis L.)

    PubMed Central

    Edwards, Miriam

    1976-01-01

    Charlock (Sinapis arvensis L.) seeds were imbibed with 10 mm GA3 for 24 hours at 0 C. After equilibration at 25 C, a 5-fold increase in radioactivity in the amino acids labeled from 2-14C-acetate was observed within 2 hours. The total amount of amino acids was reduced to half, and the specific radioactivity increased approximately 10-fold, indicating a diversion of metabolites for amino acid and protein synthesis in GA3-treated seeds. The rate of incorporation of l-14 C-leucine into protein was doubled. Autoradiographs showed that enhancement of protein synthesis was localized in the shoot and root meristems, the developing vascular tissues, and in the endosperm cells inside the testa. Images PMID:16659732

  12. 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. PMID:11903908

  13. 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.

  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. PMID:24154494

  15. 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. PMID:27246561

  16. 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.

  17. Deep RNA-Seq to unlock the gene bank of floral development in Sinapis arvensis.

    PubMed

    Liu, Jia; Mei, Desheng; Li, Yunchang; Huang, Shunmou; Hu, Qiong

    2014-01-01

    Sinapis arvensis is a weed with strong biological activity. Despite being a problematic annual weed that contaminates agricultural crop yield, it is a valuable alien germplasm resource. It can be utilized for broadening the genetic background of Brassica crops with desirable agricultural traits like resistance to blackleg (Leptosphaeria maculans), stem rot (Sclerotinia sclerotium) and pod shatter (caused by FRUITFULL gene). However, few genetic studies of S. arvensis were reported because of the lack of genomic resources. In the present study, we performed de novo transcriptome sequencing to produce a comprehensive dataset for S. arvensis for the first time. We used Illumina paired-end sequencing technology to sequence the S. arvensis flower transcriptome and generated 40,981,443 reads that were assembled into 131,278 transcripts. We de novo assembled 96,562 high quality unigenes with an average length of 832 bp. A total of 33,662 full-length ORF complete sequences were identified, and 41,415 unigenes were mapped onto 128 pathways using the KEGG Pathway database. The annotated unigenes were compared against Brassica rapa, B. oleracea, B. napus and Arabidopsis thaliana. Among these unigenes, 76,324 were identified as putative homologs of annotated sequences in the public protein databases, of which 1194 were associated with plant hormone signal transduction and 113 were related to gibberellin homeostasis/signaling. Unigenes that did not match any of those sequence datasets were considered to be unique to S. arvensis. Furthermore, 21,321 simple sequence repeats were found. Our study will enhance the currently available resources for Brassicaceae and will provide a platform for future genomic studies for genetic improvement of Brassica crops. PMID:25192023

  18. Positive correlation between menthol content and in vitro menthol tolerance in Mentha arvensis L. cultivars.

    PubMed

    Shasany, A K; Khanuja, S P; Dhawan, S; Kumar, S

    2000-09-01

    Menthol is a highly valued monoterpene produced by Japanese mint (Mentha arvensis) as a natural product with wide applications in cosmetics, confectionery, flavours, beverages and therapeutics. Selection of high menthol yielding genotypes is therefore the ultimate objective of all genetic improvement programmes in Mentha arvensis. A positive correlation was observed in the present study between menthol content in oils of evaluated genotypes and the level of tolerance to externally supplied menthol of explants of these genotypes in culture medium. The easy use of this relationship as a selectable biochemical marker opens the practical applicability of large scale in vitro screening of the germplasm, clones and breeders' material for selection of elite genotypes. PMID:11022228

  19. 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. PMID:26922695

  20. 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. PMID:16637219

  1. 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

  2. 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. PMID:22314667

  3. 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.

  4. Leaf extracts from Moricandia arvensis promote antiproliferation of human cancer cells, induce apoptosis, and enhance antioxidant activity.

    PubMed

    Skandrani, Ines; Boubaker, Jihed; Bhouri, Wissem; Limem, Ilef; Kilani, Soumaya; Ben Sghaier, Mohamed; Neffati, Aicha; Bouhlel, Ines; Ghedira, Kamel; Chekir-Ghedira, Leila

    2010-01-01

    The in vitro antiproliferative, apoptotic, and antioxidant activities from leaf extracts of Moricandia arvensis, which are used in traditional cooking and medicines, were investigated. The MTT assay revealed that only TOF (total oligomer flavonoids), ethyl acetate (EA), chloroform (Chl), and petroleum ether (PE) extracts inhibited the proliferation of K562 cells. Apoptosis plays a very important role in the treatment of cancer by promoting the apoptosis of cancer cells and limiting the concurrent death of normal cells. Thus, the possible effects of M. arvensis extracts on the induction of apoptosis in human leukemic cells (K562 cells) were investigated. The electrophoretic analysis of DNA fragmentation confirms that TOF, Chl, PE, and EA extracts provoke DNA fragmentation. Using the lipid peroxidation inhibitory assay, the antioxidant capacity of M. arvensis extracts was evaluated by the ability of each extract to inhibit malondialdehyde formation. It was revealed that EA and TOF extracts are the most active in scavenging the hydroxyl radicals. PMID:19995267

  5. 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

  6. Moricandia arvensis extracts protect against DNA damage, mutagenesis in bacteria system and scavenge the superoxide anion.

    PubMed

    Skandrani, Ines; Bouhlel, Ines; Limem, Ilef; Boubaker, Jihed; Bhouri, Wissem; Neffati, Aicha; Ben Sghaier, Mohamed; Kilani, Soumaya; Ghedira, Kamel; Ghedira-Chekir, Leila

    2009-02-01

    The mutagenic potential of total aqueous, total oligomers flavonoids (TOF), ethyl acetate (EA), chloroform (Chl), petroleum ether (PE) and methanol (MeOH) extracts from aerial parts of Moricandia arvensis was assessed using Ames Salmonella tester strains TA100 and TA1535 with and without metabolic activation (S9), and using plasmid pBluescript DNA assay. None of the different extracts produced a mutagenic effect, except aqueous extract when incubated with Salmonella typhimurium TA100 after metabolic activation. Likewise, the antimutagenicity of the same extracts was tested using the "Ames test". Our results showed that M. arvensis extracts possess antimutagenic effects against sodium azide (SA) in the two tested Salmonella assay systems, except metabolized aqueous and PE extracts when tested with S. typhimurium TA100 assay system. Different extracts were also found to be effective in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals, except PE and aqueous extracts. Antioxidant capacity of the tested extracts was evaluated using the enzymatic (xanthine/xanthine oxidase assay) (X/XOD) and the non enzymatic (NBT/Riboflavine assay) systems. TOF extract was the more effective one in inhibiting both xanthine oxidase activity and NBT reduction. PMID:19015021

  7. 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. PMID:26536372

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed Central

    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. PMID:26536372

  11. 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

  12. Inorganic materials as ameliorants for soil remediation of metal toxicity to wild mustard (Sinapis arvensis L.).

    PubMed

    Ribeiro Filho, Mateus Rosas; Siqueira, José Oswaldo; Vangronsveld, Jaco; Soares, Cláudio Roberto Fonsêca Sousa; Curi, Nilton

    2011-01-01

    The ameliorating effects of different inorganic materials were investigated on a soil originating from a zinc smelter dumping site contaminated by toxic metals. Wild mustard (Sinapis arvensis L.) was used as a test plant. The soil was amended with different doses of mining sludge, Perferric Red Latosol (LVj), steel shots, cyclonic ash, silifertil, and superphosphate. The most effective amendments improved plant growth with 45% and reduced metal uptake by over 70% in comparison to untreated soil. Reductions in availability as estimated by BaCl2-extractable metals reached up to 90% for Zn and 65% for Cd as compared to unamended soil. These reductions were associated with lower shoot and root metal contents. Shoot Zn content was reduced from 1,369 microg g(-1) in plants grown on untreated soil to 377 microg g(-1) when grown on cyclonic ash amended soil while Cd decreased from 267 to 44 microg g(-1) in steel shots amended soil. Superphosphate addition had no ameliorating effect. On the contrary, it increased BaCl2-extractable amounts of Zn. Considering all parameters we determined, steel shots, cyclonic ash and silifertil are the most promising for remediating metal contaminated soil in the tropics. Further studies evaluating impacts, cost-effectiveness and durability of effects will be conducted. PMID:21598779

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

    PubMed Central

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

    2015-01-01

    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 4–48 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. PMID:26258120

  14. 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

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

    PubMed

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

    2015-01-01

    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 4-48 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. PMID:26258120

  16. 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.

  17. 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

  18. 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

  19. Efficacy of essential oils of Caesulia axillaris and Mentha arvensis against some storage pests causing biodeterioration of food commodities.

    PubMed

    Varma, J; Dubey, N K

    2001-09-01

    The essential oils of Caesulia axillaris and Mentha arvensis have been tested for their fumigant activity in the management of biodeterioration of stored wheat samples by Aspergillus flavus and the insect pests, Sitophilus oryzae and Tribolium castaneum, at 1300 and 600 ppm, respectively. The findings indicate the efficacy of the oils as potent fumigants for management of the biodeterioration of stored wheat samples. The oils also controlled the blue mould rot of oranges caused by Penicillium italicum and enhanced the market life of the oranges for a considerable period, showing their efficacy as postharvest fungicides of higher plant origin. PMID:11529443

  20. 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. PMID:25698113

  1. 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

  2. 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. PMID:24136374

  3. 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. PMID:25654134

  4. 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

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

    PubMed

    Ripka, Géza

    2014-01-01

    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). PMID:25543737

  6. 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.

  7. 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. PMID:22804340

  8. 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. PMID:23568184

  9. 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.

  10. Nonadaptive processes governing early stages of polyploid evolution: Insights from a primary contact zone of relict serpentine Knautia arvensis (Caprifoliaceae).

    PubMed

    Hanzl, Martin; Kolář, Filip; Nováková, Dora; Suda, Jan

    2014-06-11

    • Premise of the study: Contact zones between polyploids and their diploid progenitors may provide important insights into the mechanisms of sympatric speciation and local adaptation. However, most published studies investigated secondary contact zones where the effects of genome duplication can be confounded by previous independent evolution of currently sympatric cytotypes. We compared genetically close diploid and autotetraploid serpentine cytotypes of Knautia arvensis (Caprifoliaceae) in a primary contact zone and evaluated the role of adaptive and nonadaptive processes for cytotype coexistence.• Methods: DNA flow cytometry was used to determine ploidy distribution at various spatial scales (from across the entire contact zone to microgeographic). Habitat preferences of diploids and polyploids were assessed by comparing vegetation composition of nearby ploidy-uniform sites and by recording plant species immediately surrounding both cytotypes in mixed-ploidy plots.• Key results: Tetraploids considerably outnumbered their diploid progenitors in the contact zone. Both cytotypes were segregated at all investigated spatial scales. This pattern was not driven by ecological shifts, because both diploids and tetraploids inhabited sites with nearly identical vegetation cover. Certain interploidy niche differentiation was indicated only at the smallest spatial scale; ecologically nonadaptive processes were most likely responsible for this difference.• Conclusions: We conclude that a shift in ecological preferences (i.e., the adaptive scenario) is not necessary for the establishment and evolutionary success of autopolyploid derivatives in primary contact zones. Spatial segregation that would support ploidy coexistence can also be achieved by ecologically nonadaptive processes, including the founder effect, limited dispersal ability, intense clonal growth, and triploid block. PMID:24920762

  11. Assessment of phenolic content, free-radical-scavenging capacity genotoxic and anti-genotoxic effect of aqueous extract prepared from Moricandia arvensis leaves.

    PubMed

    Skandrani, I; Limem, I; Neffati, A; Boubaker, J; Ben Sghaier, M; Bhouri, W; Bouhlel, I; Kilani, S; Ghedira, K; Chekir-Ghedira, L

    2010-02-01

    The present study was undertaken to provide a set of data on the safety of an aqueous extract (AQE) from Moricandia arvensis. For this reason, Escherichia coli tested strains PQ35 and PQ37 were used to detect induction of DNA lesions by AQE. The SOS Chromotest showed that AQE induced a marginally genotoxic effect, as expressed by the induction factor (IF) value only with E. coli PQ37 tested strain (IF=1.77 at a dose of 250 microg/assay). The measurement of the anti-genotoxic activity of the AQE was also studied by inhibition of beta-galactosidase induction. A significant anti-genotoxic effect was observed with different tested doses of AQE, which suggests that M. arvensis extract has the potential to protect DNA from the action of nitrofurantoïn (NF) and free radicals generated by hydrogen peroxide (H2O2). In addition to anti-genotoxic activity, AQE showed a free-radical-scavenging capacity towards ABTS+* and DPPH*. Total phenolic content was also evaluated following Folin-Ciocalteu method and results indicated high correlation between total phenol content and anti-genotoxic and antioxidant activities for AQE, but the highest correlation was showed with its capacity to stabilize ABTS+* (R2=0.9944). PMID:19951736

  12. 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. PMID:26304428

  13. 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

  14. 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. PMID:12688470

  15. 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. PMID:26396373

  16. 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. PMID:25648520

  17. 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. PMID:19763744

  18. 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

  19. 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

  20. 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. PMID:23514759

  1. 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. PMID:11708758

  2. 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. PMID:26793308

  3. 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.

  4. 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.

  5. Surface thermography

    SciTech Connect

    Ulrickson, M.

    1986-05-01

    The temperature sensitivity of many plasma materials interactions in both fusion plasmas and process plasmas requires the determination of the surface temperature of the material in contact with the plasma. The determination of the surface temperature is made difficult by the presence of the plasma, the large electrical potentials that may be present, and the need to not contaminate the surface. Radiation thermography permits determination of the surface temperature while overcoming the difficulties listed above. This paper briefly discusses thermal radiation, Planck's Law, and the selection of the best wavelength band for a given temperature range. Both one and two color pyrometry are discussed. Several considerations that are necessary for practical applications are discussed. Some examples of the use of radiation thermometry in fusion applications between 350 and 3000 /sup 0/C are presented. Surface heat flux has also been determined from the time variation of the surface temperature.

  6. Superhydrophobic surfaces

    SciTech Connect

    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.

  7. 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

  8. Trapped Surfaces

    NASA Astrophysics Data System (ADS)

    Senovilla, José M. M.

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are discussed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance discussed.

  9. Trapped Surfaces

    NASA Astrophysics Data System (ADS)

    Senovilla, José M. M.

    2013-03-01

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are pointed out, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are analyzed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance briefly discussed.

  10. 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.

  11. Surface Analysis

    SciTech Connect

    Not Available

    2006-06-01

    In the Surface Analysis group, within the National Center for Photovoltaic's Measurements and Characterization Division, we use surface analytical techniques help to determine the chemical, elemental, and molecular composition, and electronic structure of material surfaces and interfaces. The properties of the surface and outer few micrometers of a material often control the electrical, chemical, or mechanical properties of that material--hence, this region is of extreme importance. Our techniques use ions, electrons, and X-ray or ultraviolet photons in high vacuum to probe surfaces and interfaces of a material. We map the elemental and chemical composition of specimens, study impurities and grain boundaries, gather bonding and chemical-state information, measure surface electronic properties, and perform depth profiles to determine doping and elemental distributions. We have analyzed a wide range of materials, including photovoltaics, microelectronics, polymers, and biological specimens. We work collaboratively with you to solve materials- and device-related R&D problems. This sheet describes our major technique capabilities.

  12. 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/

  13. Surface Variety

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA02175 Surface Variety This image of part of Aram Chaos shows two different surface textures with distinctly different brightnesses. The lighter layer appears to be on top (therefore younger) than the darker surface.

    Image information: VIS instrument. Latitude 2.1N, Longitude 338.7E. 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.

  14. Surface Texture

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03191 Surface Texture

    Now that all the frost is gone, the south polar region is exhibiting more than just layering and surface markings. As this image shows, the polar surface is not smooth at this resolution.

    Image information: VIS instrument. Latitude 85.9S, Longitude 192.5E. 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. Eroded Surfaces

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 19 August 2003

    The knobby terrain and eroded impact crater observed in this THEMIS image of the Eumenides Dorsum region are evidence to a surface that has been heavily modified and stripped over time. Variable layering of material within the impact crater suggest a succession of events which eroded the surface and exposed possibly different units. Slope streaks and dust avalanches are also observed within the impact crater and point to recent and continued modification of the surface.

    Image information: VIS instrument. Latitude 4.9, Longitude 203.6 East (156.4 West). 19 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.

  16. Fractured Surface

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03084 Fractured Surface

    These fractures and graben are part of Gordii Fossae, a large region that has undergone stresses which have cracked the surface.

    Image information: VIS instrument. Latitude 16.6S, Longitude 234.3E. 18 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. Surface Textures

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 8 May 2003

    The variable surface textures observed in this THEMIS image are the result of different lava flow units. Flow fronts indicate material was once semi-fluid and filled in pre-existing impact craters. Channels observed in the eastern half of the image suggest additional materials may have once flowed and eroded older units.

    Image information: VIS instrument. Latitude 36.5, Longitude 217.6East (142.4). 19 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.

  18. Overview on surface representations for freeform surfaces

    NASA Astrophysics Data System (ADS)

    Gross, H.; Brömel, A.; Beier, M.; Steinkopf, R.; Hartung, J.; Zhong, Y.; Oleszko, M.; Ochse, D.

    2015-09-01

    Freeform surfaces are a new and exciting opportunity in lens design. The technological boundary conditions for manufacturing surfaces with reduced symmetry are complicated. Recently the progress in understanding and controlling this kind of components is ready for use in commercial products. Nearly all procedures of classical design development are changing, if freeform surfaces are used. The mathematical description of the surfaces, the optimization algorithms in lens design and their convergence, the initial design approaches, the evaluation of performance over the field of view, the data transfer in the mechanical design software and in the manufacturing machines, the metrology for characterization of real surfaces and the return of the real surfaces into the simulation are affected. In this contribution, in particular an overview on possible mathematical formulations of the surfaces is given. One of the requirements on the descriptions is a good performance to correct optical aberrations. After fabrication of real surfaces, there are typical deviations seen in the shape. First more localized deformations are observed, which are only poorly described by mode expansions. Therefore a need in describing the surface with localized finite support exists. Secondly the classical diamond turning grinding process typically shows a regular ripple structure. These midfrequency errors are best described by special approaches. For all these cases it would be the best to have simple, robust solutions, that allow for fast calculation in fitting measured surfaces and in raytrace.

  19. 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

  20. 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.

  1. 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.

  2. Surface Temperature Assimilation in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1999-01-01

    This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red-Arkansas basin in the Southwestern United States (31 degs 50 sec N - 36 degrees N, 94 degrees 30 seconds W - 104 degrees 3 seconds W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

  3. Surface Temperature Assimilation in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1997-01-01

    This paper examines the utilization of surface temperature as a variable to be assimilated in offline land surface hydrological models. Comparisons between the model computed and satellite observed surface temperatures have been carried out. The assimilation of surface temperature is carried out twice a day (corresponding to the AM and PM overpass of the NOAA10) over the Red- Arkansas basin in the Southwestern United States (31 deg 50 min N - 36 deg N, 94 deg 30 min W - 104 deg 30 min W) for a period of one year (August 1987 to July 1988). The effect of assimilation is to reduce the difference between the surface soil moisture computed for the precipitation and/or shortwave radiation perturbed case and the unperturbed case compared to no assimilation.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. Lifetime of surface nanodroplets and surface nanobubbles

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Lohse, Detlef

    2014-11-01

    Surface nanodroplets are nanoscopic emulsion droplets (e.g. of oil) on (hydrophobic) substrates immersed in water. Correspondingly, surface nanobubbles are nanoscopic gaseous domains on water-immersed substrates. Both can form through local oversaturation of the water with oil or gas, respectively. Such local oversaturation can be achieved through solvent exchange. Here we study the lifetime of such surface nanodroplets and nanobubbles in clean and degassed water, showing how both dissolve over time. We highlight pinning effect which considerably extend the lifetime of both surface nanodroplets and nanobubbles and reveal stick-slip motion of the three phase contact line during the dissolution process. We also discuss collective effects which extend the lifetime too.

  11. 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.

  12. Laser textured surface gradients

    NASA Astrophysics Data System (ADS)

    Ta, Van Duong; Dunn, Andrew; Wasley, Thomas J.; Li, Ji; Kay, Robert W.; Stringer, Jonathan; Smith, Patrick J.; Esenturk, Emre; Connaughton, Colm; Shephard, Jonathan D.

    2016-05-01

    This work demonstrates a novel technique for fabricating surfaces with roughness and wettability gradients and their subsequent applications for chemical sensors. Surface roughness gradients on brass sheets are obtained directly by nanosecond laser texturing. When these structured surfaces are exposed to air, their wettability decreases with time (up to 20 days) achieving both spatial and temporal wettability gradients. The surfaces are responsive to organic solvents. Contact angles of a series of dilute isopropanol solutions decay exponentially with concentration. In particular, a fall of 132° in contact angle is observed on a surface gradient, one order of magnitude higher than the 14° observed for the unprocessed surface, when the isopropanol concentration increased from 0 to 15.6 wt%. As the wettability changes gradually over the surface, contact angle also changes correspondingly. This effect offers multi-sensitivity at different zones on the surface and is useful for accurate measurement of chemical concentration.

  13. 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.

  14. Durable superoleophobic polypropylene surfaces.

    PubMed

    Brown, Philip S; Bhushan, Bharat

    2016-08-01

    Polypropylene (PP) is a popular plastic material used in consumer packaging. It would be desirable if such plastic containers were liquid repellent and not so easily fouled by their contents. Existing examples of superoleophobic surfaces typically rely on poorly adhered coatings or delicate surface structures, resulting in poor mechanical durability. Here, we report a facile method for creating superoleophobic PP surfaces via incorporation of nanoparticles (NPs) into the polymer surface. A solvent-NP-PP mixture was spin coated at high temperature to achieve the necessary roughness. Such surfaces were further functionalized with fluorosilane to result in a durable, super-repellent surface. They were also found to exhibit some repellency towards shampoos. This method of incorporating NPs into polymer surfaces could also prove useful in improving the anti-bacterial, mechanical and liquid-repellent properties of plastic devices.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354730

  15. 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...

  16. Surface Analysis System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A variety of surface analysis techniques are used for the qualitative and quantitative evaluation material surfaces at an atomic level. This work is accomplished in a pristine ultrahigh vacuum environment to eliminate interference.

  17. 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)

  18. Surface tension driven convection

    NASA Technical Reports Server (NTRS)

    Ostrach, S.

    1979-01-01

    In a normal gravitational environment, the free surface of a liquid in a container plays a passive role in the transport processes. However, at microgravity, the free surface can become the dominant factor. A simple but meaningful spaceflight experiment is proposed to investigate the nature and extent of flows induced by surface-tension gradients along the free surface. The influences of container geometry, wetability, contamination, and imposed heating modes will be investigated.

  19. Surface drip irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  20. 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)

  1. Control surface actuator

    NASA Technical Reports Server (NTRS)

    Seidel, Gerhard E. (Inventor)

    1988-01-01

    A device which actuates aircraft control surfaces is disclosed. The actuator is disposed entirely within the control surface structure. This allows the gap between the wing structural box and the control surface to be reduced. Reducing the size of the gap is especially desirable for wings with high aspect ratio, wherein the volume of the structural box is at a premium.

  2. PSC: protein surface classification

    PubMed Central

    Tseng, Yan Yuan; Li, Wen-Hsiung

    2012-01-01

    We recently proposed to classify proteins by their functional surfaces. Using the structural attributes of functional surfaces, we inferred the pairwise relationships of proteins and constructed an expandable database of protein surface classification (PSC). As the functional surface(s) of a protein is the local region where the protein performs its function, our classification may reflect the functional relationships among proteins. Currently, PSC contains a library of 1974 surface types that include 25 857 functional surfaces identified from 24 170 bound structures. The search tool in PSC empowers users to explore related surfaces that share similar local structures and core functions. Each functional surface is characterized by structural attributes, which are geometric, physicochemical or evolutionary features. The attributes have been normalized as descriptors and integrated to produce a profile for each functional surface in PSC. In addition, binding ligands are recorded for comparisons among homologs. PSC allows users to exploit related binding surfaces to reveal the changes in functionally important residues on homologs that have led to functional divergence during evolution. The substitutions at the key residues of a spatial pattern may determine the functional evolution of a protein. In PSC (http://pocket.uchicago.edu/psc/), a pool of changes in residues on similar functional surfaces is provided. PMID:22669905

  3. 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

  4. 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.

  5. Nitinol Surfaces for Implantation

    NASA Astrophysics Data System (ADS)

    Shabalovskaya, Svetlana; Rondelli, Gianni; Rettenmayr, Markus

    2009-08-01

    Nitinol, a group of nearly equiatomic Ni-Ti alloys, steadily conquers new areas of application. Because of the need to keep a low profile of miniature implant devices, and considering the lack of compatibility between Nitinol superelasticity and the mechanical properties of traditional coatings, bare surfaces are of interest. In this article, an overview of our studies of bare Nitinol surfaces is presented, and the performance of coated surfaces is outlined. Together dense and porous Nitinol offer a wide array of surface topographies, suitable for attachment and migration of biological cells and tissue ingrowth. Native Nitinol surface oxides vary from amorphous to crystalline and exhibit semiconducting properties associated with better blood compatibility. Nitinol surfaces are analyzed with regard to high and lasting nickel release in vitro. Surface oxide thickness and Nitinol intermetallic particulates are discussed in relation to corrosion resistance and mechanical performance of the material.

  6. 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. PMID:27330895

  7. Preservation of surface features on semiconductor surfaces

    SciTech Connect

    Wilt, D.P.

    1989-02-14

    A semiconductor laser is described comprising a Group III-V compound semiconductor body having a major surface, p1 an optical grating on the major surface, a protective coating on the grating, the coating including a transition metal, a Group III-V compound semiconductor heterostructure formed on the coating, the heterostructure having the shape of a mesa and including a Group III-V compound semiconductor active layer, a current-blocking Group III-V compound semiconductor structure laterally adjacent the mesa and effective to direct the primary flow of current through the mesa during operation of the laser, and means forming electrical contact to the laser.

  8. 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.

  9. Visualization of Seifert surfaces.

    PubMed

    van Wijk, Jarke J; Cohen, Arjeh M

    2006-01-01

    The genus of a knot or link can be defined via Seifert surfaces. A Seifert surface of a knot or link is an oriented surface whose boundary coincides with that knot or link. Schematic images of these surfaces are shown in every text book on knot theory, but from these it is hard to understand their shape and structure. In this paper, the visualization of such surfaces is discussed. A method is presented to produce different styles of surface for knots and links, starting from the so-called braid representation. Application of Seifert's algorithm leads to depictions that show the structure of the knot and the surface, while successive relaxation via a physically based model gives shapes that are natural and resemble the familiar representations of knots. Also, we present how to generate closed oriented surfaces in which the knot is embedded, such that the knot subdivides the surface into two parts. These closed surfaces provide a direct visualization of the genus of a knot. All methods have been integrated in a freely available tool, called SeifertView, which can be used for educational and presentation purposes. PMID:16805258

  10. 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.

  11. 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.

  12. Handsfree Surface Analysis

    SciTech Connect

    2006-11-01

    The HANDSFREE SURFACE ANALYSIS software code enables unattended analysis of surfaces by desorption electrospray (DESI) and liquid-junction surface sampling probe (SSP) mass spectrometry. The software allows automated lane scanning, imaging (e.g. lane rastering), spot and array sampling, and array scanning methods by controlling the movement of the sample attached to a computer-controlled stage. The software is able to collect, visualize and analyze mass spectrometry data real-time for surface analysis purposes by interacting with mass spectrometry instrumentation software. The software also enables data post processing for imaging and other analytical purposes. The software also contains image analysis approaches to control the sampling capillary-to-surface distance when used with DESI, and for automated formation and real-time reoptimization of the sampling probe-to-surface liquid microjunction when used with SSP. Control of these distances is essential to automated, hands-free operation of a DESI or SSP mass spectrometry system.

  13. Collapse of Surface Nanobubbles

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    Surface nanobubbles are nanoscopic gaseous domains that entrap on immersed solid surfaces in water. They are surprisingly stable and are difficult to be distinguished from polymeric/hydrophobic drops and solid particles (contamination). Here, we report a comparative study of contact line motion across surface nanobubbles, polymeric drops and solid particles. We show that surface nanobubbles spontaneously collapse once contact line touches them while a fast jump process and a pinning process are observed on polymeric drops and on solid particles, respectively. These distinct contact line dynamics provide a new approach to identify surface nanobubbles. The collapse of surface nanobubbles demonstrates their gaseous property and also indicates that they are metastable. The collapse process last few milliseconds with a characteristic speed of 0.1 mm/s, which is much longer and slower than that of hydrodynamic phenomena. We further show that the collapse phenomenon can be explained with a microscopic contact line dynamics.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Incompressible Flows Free Surfaces

    Energy Science and Technology Software Center (ESTSC)

    1992-02-01

    NASA-VOF3D is a three-dimensional, transient, free surface, incompressible fluid dynamics program. It is specifically designed to calculate confined flows in a low gravity environment in which surface physics must be accurately treated. It allows multiple free surfaces with surface tension and wall adhesion and includes a partial cell treatment that allows curved boundaries and internal obstacles. Variable mesh spacing is permitted in all three coordinate directions. Boundary conditions available are rigid free-slip wall, rigid no-slipmore » wall, continuative, periodic, and specified pressure outflow boundary.« less

  20. 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

  1. Surface Finishing for Biomaterials

    NASA Astrophysics Data System (ADS)

    Mizutani, Masayoshi; Komotori, Jun; Nagata, Jin; Katahira, Kazutoshi; Ohmori, Hitoshi

    Conventional biomaterials, such as titanium alloys, require enhanced chemical stability and wear resistance, which are dependent on the quality of the surficial oxide layer. However, it is very difficult to produce a sufficiently homogenous oxide layer by polishing using isolation abrasive alone. In our previous study, we proposed a new electrical grinding method (ELID grinding). The process improves oxide formation on the finished surface, resulting in finished surfaces with very thick and potentially stable oxide layers. In this study, to ensure the fabrication of surface with desirable characteristics for biomaterials, three types of specimens, which were processed with different surface finishing methods were prepared. Processed surfaces were analyzed by using an Energy Dispersive X-ray analyzer (EDX). To measure the thickness of surface oxide layers, detailed observation were performed by using a Transmission Electron Microscope (TEM). Although the ELID ground surface shows a higher value of surface roughness, excellent corrosion resistance was observed as compared with the samples finished by polishing. This is because of the formation of a thick oxide layer on the finished surface by ELID grinding. Consequently, ELID grinding appears to offer significant future promise for use in biomaterials and other engineering components subjected to the corrosion process.

  2. 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

  3. Martian surface simulations

    NASA Astrophysics Data System (ADS)

    Gaskell, R. W.

    1993-06-01

    Computer generated surfaces have been created to aid in imaging, landing and rover studies for Mars and the moon. They are also being applied to the study of cratering histories. The surfaces are generated in steps which attempt to mimic geologic episodes. Surface roughness is realized fractally, while craters and other specific features have shapes and distributions dictated by observation. Surface materials are assigned appropriate albedos, making the images more realistic. With the inclusion of correlations between crater and rock distributions, the simulations are beginning to acquire a predictive capability.

  4. 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.

  5. Histophilus somni Surface Proteins.

    PubMed

    Corbeil, Lynette B

    2016-01-01

    The pathogen surface is usually the first site of interaction with the host. Histophilus somni was earlier thought to only have an outer membrane on its surface. Now it is known that the surface is composed of many virulence factors, including outer membrane proteins, lipooligosaccharide or endotoxin, a fibrillar network, and an exopolysaccharide. Outer membrane blebs, endotoxin, the fibrillar network, and the exopolysaccharide are also shed from the surface. This review will focus on the surface proteins of this pathogen that may colonize the mucosal surface of ruminants as a commensal or may cause pneumonia, septicemia, myocarditis, thrombotic meningoencephalitis, arthritis, and/or abortion. The major outer membrane protein has been well studied. Since its size and epitopes vary from strain to strain, it may be useful for typing strains. Iron-regulated OMPs have also received much attention because of their role in iron uptake for in vivo growth of H. somni. Other OMPs may be protective, based on passive immunization with monospecific antibodies and active immunization experiments. The surface and shed fibrillar network has been shown to be an immunoglobulin-binding protein in that it binds bovine IgG2 by the Fc portion. Two repeat domains (DR1 and DR2) have cytotoxic Fic motifs. Vaccine studies with recombinant DR2 are promising. Studies of the bacterial genome as well as comparison of surface proteins of different strains from the various H. somni syndromes and carrier states will be discussed and have provided much insight into pathogenesis and protection. PMID:26728061

  6. 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)

  7. Mechanically durable superhydrophobic surfaces.

    PubMed

    Verho, Tuukka; Bower, Chris; Andrew, Piers; Franssila, Sami; Ikkala, Olli; Ras, Robin H A

    2011-02-01

    Development of durable non-wetting surfaces is hindered by the fragility of the microscopic roughness features that are necessary for superhydrophobicity. Mechanical wear on superhydrophobic surfaces usually shows as increased sticking of water, leading to loss of non-wettability. Increased wear resistance has been demonstrated by exploiting hierarchical roughness where nanoscale roughness is protected to some degree by large scale features, and avoiding the use of hydrophilic bulk materials is shown to help prevent the formation of hydrophilic defects as a result of wear. Additionally, self-healing hydrophobic layers and roughness patterns have been suggested and demonstrated. Nevertheless, mechanical contact not only causes damage to roughness patterns but also surface contamination, which shortens the lifetime of superhydrophobic surfaces in spite of the self-cleaning effect. The use of photocatalytic effect and reduced electric resistance have been suggested to prevent the accumulation of surface contaminants. Resistance to organic contaminants is more challenging, however, oleophobic surface patterns which are non-wetting to organic liquids have been demonstrated. While the fragility of superhydrophobic surfaces currently limits their applicability, development of mechanically durable surfaces will enable a wide range of new applications in the future. PMID:21274919

  8. Improving Surface Irrigation Performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. 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.

  10. Surface composition of alloys

    NASA Astrophysics Data System (ADS)

    Sachtler, W. M. H.

    1984-11-01

    In equilibrium, the composition of the surface of an alloy will, in general, differ from that of the bulk. The broken-bond model is applicable to alloys with atoms of virtually equal size. If the heat of alloy formation is zero, the component of lower heat of atomization is found enriched in the surface. If both partners have equal heats of sublimination, the surface of a diluted alloy is enriched with the minority component. Size effects can enhance or weaken the electronic effects. In general, lattice strain can be relaxed by precipitating atoms of deviating size on the surface. Two-phase alloys are described by the "cherry model", i.e. one alloy phase, the "kernel" is surrounded by another alloy, the "flesh", and the surface of the outer phase, the "skin" displays a deviating surface composition as in monophasic alloys. In the presence of molecules capable of forming chemical bonds with individual metal atoms, "chemisorption induced surface segregation" can be observed at low temperatures, i.e. the surface becomes enriched with the metal forming the stronger chemisorption bonds.

  11. 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.

  12. 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…

  13. Reducing Xanthomonas from surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Removal of the citrus canker organism, Xanthomonas axonopodis pv citri , from the surfaces of packinglines is just as important an issue facing the citrus fresh fruit packers as removing the bacteria from the fruit surfaces. Current allowable washes and rinses do not adequately clean the lines and ...

  14. 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

  15. Hydrogen on semiconductor surfaces

    SciTech Connect

    Schaefer, J.A.; Balster, T.; Polyakov, V.; Rossow, U.; Sloboshanin, S.; Starke, U.; Tautz, F.S.

    1998-12-31

    The authors review structural and electronic aspects of the reaction of hydrogen with semiconductor surfaces. Among others, they address the Si(100), Ge{sub x}Si{sub 1{minus}x}(100), GaAs(100), InP(100), SiC(100), SiC(0001) and SiC(000{bar 1}) surfaces. It is demonstrated that high resolution electron energy loss spectroscopy (HREELS) in conjunction with a number of other surface sensitive techniques like low energy electron diffraction (LEED) and photoelectron spectroscopy (XPS/UPS) can yield important information about the surface atomic structure, the effects of hydrogen passivation and etching and on electronic properties of the surfaces. 67 refs., 7 figs., 3 tabs.

  16. 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.

  17. 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.

  18. Electrohydrodynamics Near Hydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  19. 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

  20. 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.

  1. Antibacterial Au nanostructured surfaces.

    PubMed

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

    2016-02-01

    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. PMID:26648134

  2. On-surface reactions.

    PubMed

    Lindner, Robert; Kühnle, Angelika

    2015-06-01

    On-surface synthesis constitutes a rapidly growing field of research due to its promising application for creating stable molecular structures on surfaces. While self-assembled structures rely on reversible interactions, on-surface synthesis provides the potential for creating long-term stable structures with well-controlled properties, for example superior electron transport for future molecular electronic devices. On-surface synthesis holds the promise for preparing insoluble compounds that cannot be produced in solution. Another highly exciting aspect of on-surface synthesis is the chance to discover new reaction pathways due to the two-dimensional confinement of the reaction educts. In this review, we discuss the current state-of-the-art and classify the reactions that have been successfully performed so far. Special emphasis is put on electrically insulating surfaces, as these substrates pose particular challenges for on-surface synthesis while at the same time bearing high potential for future use, for example, in molecular electronics. PMID:25965579

  3. 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.

  4. 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.

  5. Localized acoustic surface modes

    NASA Astrophysics Data System (ADS)

    Farhat, Mohamed; Chen, Pai-Yen; Bağcı, Hakan

    2016-04-01

    We introduce the concept of localized acoustic surface modes. We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  6. 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

  7. 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.

  8. 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.

  9. Morpheus Surface Approach

    NASA Video Gallery

    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...

  10. 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.

  11. Lunar Surface Rovers

    NASA Technical Reports Server (NTRS)

    Plescia, J. B.; Lane, A. L.; Miller, D.

    1992-01-01

    Many questions of lunar science remain unanswered because of a lack of specific data. With the potential for returning humans to the Moon and establishing a long-term presence there, a new realm of exploration is possible. Numerous plans have been outlined for orbital and surface missions. The capabilities and objectives of a small class of rovers to be deployed on the lunar surface are described. The objective of these small rovers is to collect detailed in situ information about the composition and distribution of materials on the lunar surface. Those data, in turn, would be applied to a variety of lunar geoscience questions and form a basis for planning human activities on the lunar surface.

  12. 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)

  13. Sea Surface Salinity

    NASA Video Gallery

    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...

  14. 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.

  15. 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.

  16. Interactive surface grid generation

    NASA Technical Reports Server (NTRS)

    Luh, Raymond Ching-Chung; Pierce, Lawrence E.; Yip, David

    1991-01-01

    This paper describes a surface grid generation tool called S3D. It is the result of integrating a robust and widely applicable interpolation technique with the latest in workstation technology. Employing the use of a highly efficient and user-friendly graphical interface, S3D permits real-time interactive analyses of surface geometry data and facilitates the construction of surface grids for a wide range of applications in Computational Fluid Dynamics (CFD). The design objectives are for S3D to be stand-alone and easy to use so that CFD analysts can take a hands-on approach toward most if not all of their surface grid generation needs. Representative examples of S3D applications are presented in describing the various elements involved in the process.

  17. 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)

  18. 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.

  19. Multifunctional thin film surface

    SciTech Connect

    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.

  20. 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.

  1. 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).

  2. 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.

  3. Handsfree Surface Analysis

    Energy Science and Technology Software Center (ESTSC)

    2006-11-01

    The HANDSFREE SURFACE ANALYSIS software code enables unattended analysis of surfaces by desorption electrospray (DESI) and liquid-junction surface sampling probe (SSP) mass spectrometry. The software allows automated lane scanning, imaging (e.g. lane rastering), spot and array sampling, and array scanning methods by controlling the movement of the sample attached to a computer-controlled stage. The software is able to collect, visualize and analyze mass spectrometry data real-time for surface analysis purposes by interacting with mass spectrometrymore » instrumentation software. The software also enables data post processing for imaging and other analytical purposes. The software also contains image analysis approaches to control the sampling capillary-to-surface distance when used with DESI, and for automated formation and real-time reoptimization of the sampling probe-to-surface liquid microjunction when used with SSP. Control of these distances is essential to automated, hands-free operation of a DESI or SSP mass spectrometry system.« less

  4. 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

  5. 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

  6. 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

  7. 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

  8. Surface energy of zinc

    SciTech Connect

    Bilello, J.C.; Dew-Hughes, D.; Pucino, A.T.

    1983-04-01

    The influence of temperature and associated dislocation microstructure on the energetics of basal plane cleavage in zinc crystals has been investigated using the method of Hull, Beardmore, and Valentine (HBV). A marked temperature dependence was observed in the zinc surface energy, over the range 77--298 /sup 0/K, contrary to previous expectations. Plastic relaxation was associated with crack initiation at 77 /sup 0/K, but not propagation; while at room temperature a plastic zone of 1200--1500 ..mu..m in depth was produced by crack extension. The surface energy could be estimated, independent of the usual Griffith analysis, by measuring the energy dissipation in a fully relaxed deformed zone associated with an explosively formed precursor crack. This method yielded surface energies of 0.066 to 0.079 J m/sup -2/ which was in good agreement with previous work. It is demonstrated that the cleavage surface energy of zinc is well below the thermodynamic surface energy and that this discrepancy is not related to plastic deformation.

  9. 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.

  10. 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

  11. How to clean surfaces

    NASA Astrophysics Data System (ADS)

    Bennett, Jean M.

    2004-06-01

    Various cleaning methods are available depending on the sizes of the parts, mounted or unmounted, and purpose of the cleaning. Dust and other particle contamination affect scattering and act as nuclei for defects in optical coatings. In some cases, these defects can initiate laser damage. Noncontact cleaning methods to eliminate particle contamination include blowing large particles from surfaces with an air bulb, "canned air," or a nitrogen gas jet, for a gentle cleaning and CO2 snow for more aggressive particle removal. Laser assisted particle removal is a new high tech method. A strip coating material applied to the surface and subsequently removed will remove large fresh particles and often fingerprints. Contamination films affect the quality and adherence of optical coatings. These are usually removed (from unmounted optics) by cleaning the surface in a detergent and water bath followed by extensive rinsing and non-contact drying. Alternate methods when immersion in water is not possible are drag wiping, or spraying or squirting organic solvents over the surface. Before cleaning, surfaces must be visually inspected to determine the type and location of the contamination, to decide if cleaning is necessary, and what type of cleaning technique to use. Finally, bad cleaning is much worse than no cleaning! Illustrations of the cleaning methods described above will be given.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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. PMID:22558187

  17. 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

  18. 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

  19. 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.

  20. Direct heating surface combustor

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.; Shire, L. I.; Mroz, T. S. (Inventor)

    1978-01-01

    The combustor utilizes a non-adiabatic flame to provide low-emission combustion for gas turbines. A fuel-air mixture is directed through a porous wall, the other side of which serves as a combustion surface. A radiant heat sink disposed adjacent to and spaced from the combustion surface controls the combustor flame temperature in order to prevent the formation of oxides of nitrogen. A secondary air flow cools the heat sink. Additionally, up to 100% of secondary air flow is mixed with the combustion products at the direct heating surface combustor to dilute such products thereby reducing exit temperature. However, if less than 100% secondary air is mixed to the combustor, the remainder may be added to the combustion products further downstream.

  1. Nonequilibrium surface tension

    NASA Astrophysics Data System (ADS)

    Lamorgese, A.; Mauri, R.

    2015-12-01

    A weakly nonlocal phase-field model is used to define surface tension in liquid binary mixtures in terms of the composition gradient in the interfacial region so that, at equilibrium, it depends linearly on the characteristic length that defines the interfacial width. In nonequilibrium conditions, surface tension changes with time: during mixing, it decreases as the inverse square root of time, while during phase separation, when nuclei coagulate, it increases exponentially to its equilibrium value. In addition, since temperature gradients modify the steepness of the concentration profile in the interfacial region, they induce gradients in the nonequilibrium surface tension, leading to the Marangoni thermocapillary migration of an isolated drop. Similarly, Marangoni stresses are induced in a composition gradient, leading to diffusiophoresis.

  2. Surface Hopping by Consensus.

    PubMed

    Martens, Craig C

    2016-07-01

    We present a new stochastic surface hopping method for modeling molecular dynamics with electronic transitions. The approach, consensus surface hopping (CSH), is a numerical framework for solving the semiclassical limit Liouville equation describing nuclear dynamics on coupled electronic surfaces using ensembles of trajectories. In contrast to existing techniques based on propagating independent classical trajectories that undergo stochastic hops between the electronic states, the present method determines the probabilities of transition of each trajectory collectively with input from the entire ensemble. The full coherent dynamics of the coupled system arise naturally at the ensemble level and ad hoc corrections, such as momentum rescaling to impose strict trajectory energy conservation and artificial decoherence to avoid the overcoherence of the quantum states associated with independent trajectories, are avoided. PMID:27345103

  3. 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.

  4. 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.

  5. Plasmons and surfaces

    NASA Astrophysics Data System (ADS)

    Ferrell, T. L.; Callcott, T. A.; Warmack, R. J.

    1985-08-01

    Plasmons, energy quanta related to electrical charge oscillations in condensed matter (such as metals), were first observed in 1955 by passing an electron beam through Al foil and measuring the resulting energy peaks of electrons which made it through. The energy, as predicted by quantum mechanics, is proportional to the associated frequency of the longitudinal waves set up as the oscillations propagate from electron to electron, and is a function of the free electron density. Plasmon data aid in characterizing the electronic state of matter under study. Performing spectroscopy of electrons bouncing off the surface permits characterizations of the electronic states of the surfaces. Plasmons can lose energy by emitting light. The wavelength of the light can be controlled by specifying the composition of a specimen. Techniques for coupling beam photons with surface plasmons to achieve excited states are discussed, along with emerging applications such as diffraction gratings for spectroscopy, holographic cameras and Raman scattering applied to biochemical studies.

  6. 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

  7. Martian surface materials

    NASA Technical Reports Server (NTRS)

    Moore, H. J.

    1991-01-01

    A semiquantitative appreciation for the physical properties of the Mars surface materials and their global variations can be gained from the Viking Lander and remote sensing observations. Analyses of Lander data yields estimates of the mechanical properties of the soil-like surface materials and best guess estimates can be made for the remote sensing signatures of the soil-like materials at the landing sites. Results show that significant thickness of powderlike surface materials with physical properties similar to drift material are present on Mars and probably pervasive in the Tharsis region. It also appears likely that soil-like materials similar to crusty to cloddy material are typical for Mars, and that soil-like material similar to blocky material are common on Mars.

  8. Stereoscopic surface perception.

    PubMed

    Anderson, B L

    1999-12-01

    Physiological, computational, and psychophysical studies of stereopsis have assumed that the perceived surface structure of binocularly viewed images is primarily specified by the pattern of binocular disparities in the two eyes' views. A novel set of stereoscopic phenomena are reported that demonstrate the insufficiency of this view. It is shown that the visual system computes the contrast relationships along depth discontinuities to infer the depth, lightness, and opacity of stereoscopically viewed surfaces. A novel theoretical framework is introduced to explain these results. It is argued that the visual system contains mechanisms that enforce two principles of scene interpretation: a generic view principle that determines qualitative scene geometry, and anchoring principles that determine how image data are quantitatively partitioned between different surface attributes. PMID:10624955

  9. 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.

  10. 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).

  11. 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

  12. Perspectives on surface nanobubbles.

    PubMed

    Zhang, Xuehua; Lohse, Detlef

    2014-07-01

    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

  13. Excitonic surface lattice resonances

    NASA Astrophysics Data System (ADS)

    Humphrey, A. D.; Gentile, M. J.; Barnes, W. L.

    2016-08-01

    Electromagnetic resonances are important in controlling light at the nanoscale. The most studied such resonance is the surface plasmon resonance that is associated with metallic nanostructures. Here we explore an alternative resonance, the surface exciton-polariton resonance, one based on excitonic molecular materials. Our study is based on analytical and numerical modelling. We show that periodic arrays of suitable molecular nanoparticles may support surface lattice resonances that arise as a result of coherent interactions between the particles. Our results demonstrate that excitonic molecular materials are an interesting alternative to metals for nanophotonics; they offer the prospect of both fabrication based on supramolecular chemistry and optical functionality arising from the way the properties of such materials may be controlled with light.

  14. 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.

  15. 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.

  16. 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

  17. Compliant layer chucking surface

    SciTech Connect

    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. 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.

  19. 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.

  20. Anti-fogging surfaces

    NASA Astrophysics Data System (ADS)

    Mouterde, Timothée; Checco, Antonio; Black, Charles; Rahman, Atikur; Clanet, Christophe; Quéré, David

    2015-11-01

    Achieving an anti-fogging material is more challenging than achieving an anti-rain material. A relevant way to investigate the resistance to fog consists of depositing hot water on a cold surface. We show that classical superhydrophobic surfaces with micron-size microstructures lose their superhydrophobic behaviour due to vapour condensation. To understand this phenomenon, we measured the adhesion force of hot water drops on different substrates and propose a quantitative description of this force generated by condensation. Our main result is that reducing the scale of the structures can strongly promote antifogging properties.

  1. Strongly correlated surface states

    NASA Astrophysics Data System (ADS)

    Alexandrov, Victor A.

    Everything has an edge. However trivial, this phrase has dominated theoretical condensed matter in the past half a decade. Prior to that, questions involving the edge considered to be more of an engineering problem rather than a one of fundamental science: it seemed self-evident that every edge is different. However, recent advances proved that many surface properties enjoy a certain universality, and moreover, are 'topologically' protected. In this thesis I discuss a selected range of problems that bring together topological properties of surface states and strong interactions. Strong interactions alone can lead to a wide spectrum of emergent phenomena: from high temperature superconductivity to unconventional magnetic ordering; interactions can change the properties of particles, from heavy electrons to fractional charges. It is a unique challenge to bring these two topics together. The thesis begins by describing a family of methods and models with interactions so high that electrons effectively disappear as particles and new bound states arise. By invoking the AdS/CFT correspondence we can mimic the physical systems of interest as living on the surface of a higher dimensional universe with a black hole. In a specific example we investigate the properties of the surface states and find helical spin structure of emerged particles. The thesis proceeds from helical particles on the surface of black hole to a surface of samarium hexaboride: an f-electron material with localized magnetic moments at every site. Interactions between electrons in the bulk lead to insulating behavior, but the surfaces found to be conducting. This observation motivated an extensive research: weather the origin of conduction is of a topological nature. Among our main results, we confirm theoretically the topological properties of SmB6; introduce a new framework to address similar questions for this type of insulators, called Kondo insulators. Most notably we introduce the idea of Kondo

  2. 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.

  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. Fluid Dynamics with Free Surfaces

    Energy Science and Technology Software Center (ESTSC)

    1992-02-01

    RIPPLE is a two-dimensional, transient, free surface incompressible fluid dynamics program. It allows multiple free surfaces with surface tension and wall adhesion forces and has a partial cell treatment which allows curved boundaries and interior obstacles.

  5. 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.

  6. Multiphonon scattering from surfaces

    NASA Astrophysics Data System (ADS)

    Manson, J. R.; Celli, V.; Himes, D.

    1994-01-01

    We consider the relationship between several different formalisms for treating the multiphonon inelastic scattering of atomic projectiles from surfaces. Starting from general principles of formal scattering theory, the trajectory approximation to the scattering intensity is obtained. From the trajectory approximation, the conditions leading to the fast-collision approximation for multiquantum inelastic scattering are systematically derived.

  7. A Thermochromic Superhydrophobic Surface.

    PubMed

    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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. SURFACE IMPOUNDMENT STUDY - RESULTS

    EPA Science Inventory

    This work product was the set of analytical outputs that characterize risks posed by managing wastes in impoundments. These analytical outputs form the basis for a decision on the regulatory status of the wastes managed in surface impoundments. The analytical outputs were devel...

  14. Surface complexation modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 and submicron physics

    NASA Astrophysics Data System (ADS)

    Wright, H. A.

    1982-04-01

    Subjects discussed at the annual radiological/physics contractors meeting held in Gettysburg, Pa., 4 May 1982 are presented. The following research projects are briefly described: resonance ionization mass spectroscopy, an extreme uv transmission grating monochrometers, electron attenuation lengths in solids, surface enhanced Raman spectroscopy, and easy events in irradiated liquid water.

  16. Random rough surface photofabrication

    NASA Astrophysics Data System (ADS)

    Brissonneau, Vincent; Escoubas, Ludovic; Flory, François; Berginc, Gérard

    2011-10-01

    Random rough surfaces are of primary interest for their optical properties: reducing reflection at the interface or obtaining specific scattering diagram for example. Thus controlling surface statistics during the fabrication process paves the way to original and specific behaviors of reflected optical waves. We detail an experimental method allowing the fabrication of random rough surfaces showing tuned statistical properties. A two-step photoresist exposure process was developed. In order to initiate photoresist polymerization, an energy threshold needs to be reached by light exposure. This energy is brought by a uniform exposure equipment comprising UV-LEDs. This pre-exposure is studied by varying parameters such as optical power and exposure time. The second step consists in an exposure based on the Gray method.1 The speckle pattern of an enlarged scattered laser beam is used to insolate the photoresist. A specific photofabrication bench using an argon ion laser was implemented. Parameters such as exposure time and distances between optical components are discussed. Then, we describe how we modify the speckle-based exposure bench to include a spatial light modulator (SLM). The SLM used is a micromirror matrix known as Digital Micromirror Device (DMD) which allows spatial modulation by displaying binary images. Thus, the spatial beam shape can be tuned and so the speckle pattern on the photoresist is modified. As the photoresist photofabricated surface is correlated to the speckle pattern used to insolate, the roughness parameters can be adjusted.

  17. 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)

  18. 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.

  19. SURFACE WATER EMAP PROJECT

    EPA Science Inventory

    The surface water component of the EPA Environmental Monitoring and Assessment Program (EMAP) Western Pilot is a five-year effort to assess the ecological condition of rivers and streams across 12 states in the western United States. EMAP is designed to monitor indicators of poll...

  20. 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.

  1. 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.

  2. 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.

  3. Active frequency selective surfaces

    NASA Astrophysics Data System (ADS)

    Buchwald, Walter R.; Hendrickson, Joshua; Cleary, Justin W.; Guo, Junpeng

    2013-05-01

    Split ring resonator arrays are investigated for use as active elements for the realization of voltage controllable frequency selective surfaces. Finite difference time domain simulations suggest the absorptive and reflective properties of such surfaces can be externally controlled through modifications of the split ring resonator gap impedance. In this work, such voltage-controlled resonance tuning is obtained through the addition of an appropriately designed high electron mobility transistor positioned across the split ring resonator gap. It is shown that a 0.5μm gate length high electron mobility transistor allows voltage controllable switching between the two resonant conditions associated with a split ring resonator and that of a closed loop geometry when the surface is illuminated with THz radiation. Partial switching between these two resonant conditions is observed at larger gate lengths. Such active frequency selective surfaces are proposed, for example, for use as modulators in THz detection schemes and as RF filters in radar applications when scaled to operate at GHz frequencies.

  4. Managing Surface Behaviors.

    ERIC Educational Resources Information Center

    Marable, Michele A.; Raimondi, Sharon L.

    1995-01-01

    Nonverbal and verbal techniques that teachers can use to manage surface behaviors are suggested, including planned ignoring, eye contact, facial expression, body posture, close proximity, touch control, limitation of space, redirection to another activity, ventilation, distraction, understanding and reassurance, modeling, humor, one-to-one…

  5. 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.

  6. Lunar surface gravimeter experiment

    NASA Technical Reports Server (NTRS)

    Giganti, J. J.; Larson, J. V.; Richard, J. P.; Tobias, R. L.; Weber, J.

    1977-01-01

    The lunar surface gravimeter used the moon as an instrumented antenna to search for gravitational waves predicted by Einstein's general theory of relativity. Tidal deformation of the moon was measured. Gravitational radiation is a channel that is capable of giving information about the structure and evolution of the universe.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    The bandstructures of [110] and [001] Bi2Te3 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.

  9. 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.

  10. NIMS Ganymede Surface Map

    NASA Technical Reports Server (NTRS)

    1996-01-01

    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.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  11. 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.

  12. 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.

  13. Vortex-Surface Collisions^

    NASA Astrophysics Data System (ADS)

    Conlisk, A. T.

    1998-11-01

    The interaction of vortices with solid surfaces occurs in many different situations including, but not limited to tornadoes, propeller wakes, flows over swept wings and missile forebodies, turbomachinery flows, blade-vortex interactions and tip vortex-surface interactions on helicopters. Often, parts of a system must operate within such flows and thus encounter these vortices. In the present paper we discuss the nature of a particular subset of interactions called ``collisions''. A ``collision'' is characterized by the fact that the core of the vortex is permanently altered; usually the core is locally destroyed. The focus is on fully three-dimensional collisions although two-dimensional collisions are discussed as well. Examples of collisions in helicopter aerodynamics and turbomachinery flows are discussed and the dynamics of the vortex core during a collision process are illustrated for a 90^o collision. ^Supported by the US Army Research Office

  14. Surface control of flexoelectricity

    NASA Astrophysics Data System (ADS)

    Stengel, Massimiliano

    2014-11-01

    The polarization response of a material to a strain gradient, known as flexoelectricity, holds great promise for novel electromechanical applications. Despite considerable recent progress, however, the effect remains poorly understood. From both the fundamental and practical viewpoints, it is of crucial importance to know whether the coupling coefficients are primarily governed by the properties of the bulk material or by the details of the sample surface. Here we provide, by means of first-principles calculations, quantitative evidence supporting the latter scenario. In particular, we demonstrate that a SrTiO3 film can yield a positive or negative voltage upon bending, depending on whether it is terminated by a TiO2 or SrO layer. This result points to a full control of the flexoelectric effect via surface/interface engineering, opening exciting new avenues for device design.

  15. 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.

  16. Surface Bubble Nucleation Stability

    NASA Astrophysics Data System (ADS)

    Seddon, James R. T.; Kooij, E. Stefan; Poelsema, Bene; Zandvliet, Harold J. W.; Lohse, Detlef

    2011-02-01

    Recent research has revealed several different techniques for nanoscopic gas nucleation on submerged surfaces, with findings seemingly in contradiction with each other. In response to this, we have systematically investigated the occurrence of surface nanobubbles on a hydrophobized silicon substrate for various different liquid temperatures and gas concentrations, which we controlled independently. We found that nanobubbles occupy a distinct region of this parameter space, occurring for gas concentrations of approximately 100%-110%. Below the nanobubble region we did not detect any gaseous formations on the substrate, whereas micropancakes (micron wide, nanometer high gaseous domains) were found at higher temperatures and gas concentrations. We moreover find that supersaturation of dissolved gases is not a requirement for nucleation of bubbles.

  17. 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.

  18. Lunar Surface Radiation Display

    NASA Astrophysics Data System (ADS)

    Burke, James; Albalat, Andrea Jaime; Tlustos, Reinhard

    2014-05-01

    Effects of the lunar surface environment can be observed with a simple passive experiment consisting of small material samples placed in view of a lander or rover camera. This paper will describe, advocate and demonstrate the creation, ideally by students or young professionals, of a small standard sample holder, for example a string of different glass beads in front of a white or detector background, that can be replicated and installed on any of the coming series of lunar surface spacecraft. Effects of solar and cosmic ionizing radiation and local temperature, such as darkening and annealing, will be readily apparent in different kinds of glass, plastic and crystalline beads. Costs of preparation and installation, and impact on the main mission, can be kept to a level essentially negligible in proportion to project budgets.

  19. Secure surface identification codes

    NASA Astrophysics Data System (ADS)

    Beekhof, F.; Voloshynovskiy, S.; Koval, O.; Villan, R.; Pun, T.

    2008-02-01

    This paper introduces an identification framework for random microstructures of material surfaces. These microstructures represent a kind of unique fingerprints that can be used to track and trace an item as well as for anti-counterfeiting. We first consider the architecture for mobile phone-based item identification and then introduce a practical identification algorithm enabling fast searching in large databases. The proposed algorithm is based on reference list decoding. The link to digital communications and robust perceptual hashing is shown. We consider a practical construction of reference list decoding, which comprizes computational complexity, security, memory storage and performance requirements. The efficiency of the proposed algorithm is demonstrated on experimental data obtained from natural paper surfaces.

  20. 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.

  1. Near surface observations

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Learning objectives include: (1) developing an understanding of the implications of the term "near surface observations"; (2) associating the appearance of large ground features as seen in satellite imagery with their appearance as seen from the ground; (3) grasping criteria and procedures for selecting training sites on the ground for use in supervised classification; (4) running through an example of training site selection; (5) becoming familiar with several methods of accuracy assessment; (6) becoming aware of the approach and value of making supporting measurements of the spectral and physical properties of materials on the ground and from aircraft; (7) taking note of the different types of instruments used in making specific ground measurements; and (8) appreciating the rationale underlying laboratory and field studies on or near the Earth's surface for the purpose of developing new sensor systems.

  2. Diffusion on strained surfaces

    NASA Astrophysics Data System (ADS)

    Schroeder, M.; Wolf, D. E.

    1997-03-01

    The change of diffusion kinetics when elastic fields are present is discussed for diffusion on (001) surfaces of simple cubic, fcc and bcc lattices. All particles interact pairwise with a Lennard-Jones potential. The simple cubic lattice was stabilized by an anisotropic prefactor. It is found that generically compressive strain enhances diffusion whereas tensile strain increases the activation barrier. An approximately linear dependence of the barrier in a wide range of misfits is found. In heteroepitaxy, diffusion on top of large clusters is inhomogeneous and anisotropic. The kinetics close to edges and centers of islands are remarkably different. In many cases changes of binding energies are small compared to those of saddle point energies. Thermodynamic arguments (minimization of free energy) are not appropriate to describe diffusion on strained surfaces in these cases.

  3. Clusters, surfaces, and catalysis

    PubMed Central

    Somorjai, Gabor A.; Contreras, Anthony M.; Montano, Max; Rioux, Robert M.

    2006-01-01

    The surface science of heterogeneous metal catalysis uses model systems ranging from single crystals to monodispersed nanoparticles in the 1–10 nm range. Molecular studies reveal that bond activation (C–H, H–H, C–C, CO) occurs at 300 K or below as the active metal sites simultaneously restructure. The strongly adsorbed molecules must be mobile to free up these sites for continued turnover of reaction. Oxide–metal interfaces are also active for catalytic turnover. Examples using C–H and CO activation are described to demonstrate these properties. Future directions include synthesis, characterization, and reaction studies with 2D and 3D monodispersed metal nanoclusters to obtain 100% selectivity in multipath reactions. Investigations of the unique structural, dynamic, and electronic properties of nanoparticles are likely to have major impact in surface technologies. The fields of heterogeneous, enzyme, and homogeneous catalysis are likely to merge for the benefit of all three. PMID:16740668

  4. 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.

  5. 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.

  6. Surface decontamination compositions and methods

    DOEpatents

    Wright; Karen E.; Cooper, David C.; Peterman, Dean R.; Demmer, Ricky L.; Tripp, Julia L.; Hull, Laurence C.

    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.

  7. 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.

  8. 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.

  9. Laser surface cleaning

    SciTech Connect

    Crivella, E.C.; Freiwald, J.; Freiwald, D.A.

    1996-12-31

    Decontamination of contaminated metal and material recycle, two of 31 priority needs identified by the D&D focus group, are the most promising applications for laser ablation within the DOE complex. F2 Associates has developed a robotic laser ablation system that is capable of high contamination rates, waste volume reduction, surface pore cleaning, and real-time characterization of materials. It is being demonstrated that this system will be the most cost-effective technology for metal decontamination and material recycle.

  10. 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.

  11. 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.

  12. 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.

  13. Surface processes on Venus

    NASA Astrophysics Data System (ADS)

    Arvidson, R. E.

    1992-12-01

    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.

  14. Surface electrical properties experiment

    USGS Publications Warehouse

    Simmons, Gene; Strangway, David; Annan, Peter; Baker, Richard G.; Bannister, Lawrence; Brown, Raymon; Cooper, William; Cubley, Dean; deBettencourt, Joseph; England, Anthony W.; Groener, John; Kong, Jin-Au; LaTorraca, Gerald; Meyer, James; Nanda, Ved; Redman, David; Rossiter, James; Tsang, Leung; Urner, Joseph; Watts, Raymond

    1973-01-01

    The surface electrical properties (SEP) experiment was used to explore the subsurface material of the Apollo 17 landing site by means of electromagnetic radiation. The experiment was designed to detect electrical layering, discrete scattering bodies, and the possible presence of water. From the analysis of the data, it was expected that values of the electrical properties (dielectric constant and loss tangent) of lunar material in situ would be obtained.

  15. Surface polymerization agents

    SciTech Connect

    Taylor, C.; Wilkerson, C.

    1996-12-01

    This is the final report of a 1-year, Laboratory-Directed R&D project at LANL. A joint technical demonstration was proposed between US Army Missile Command (Redstone Arsenal) and LANL. Objective was to demonstrate that an unmanned vehicle or missile could be used as a platform to deliver a surface polymerization agent in such a manner as to obstruct the filters of an air-breathing mechanism, resulting in operational failure.

  16. Silicon sheet surface studies

    NASA Astrophysics Data System (ADS)

    Danyluk, S.

    1985-06-01

    Results of the program are presented on developing an understanding of the basic mechanisms of abrasion and wear of silicon and on the nondestructive measurement of residual stresses in sheet silicon. Experiments were conducted at various temperatures and in the presence of various fluids. In abrasive wear, it was shown that dislocations, microtwins, and cracks are generated beneath the contact surface. Residual stresses in ribbon by the edge defined film growth process were measured by use of a shadow moire interferometry technique.

  17. 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.

  18. Progressive Precision Surface Design

    SciTech Connect

    Duchaineau, M; Joy, KJ

    2002-01-11

    We introduce a novel wavelet decomposition algorithm that makes a number of powerful new surface design operations practical. Wavelets, and hierarchical representations generally, have held promise to facilitate a variety of design tasks in a unified way by approximating results very precisely, thus avoiding a proliferation of undergirding mathematical representations. However, traditional wavelet decomposition is defined from fine to coarse resolution, thus limiting its efficiency for highly precise surface manipulation when attempting to create new non-local editing methods. Our key contribution is the progressive wavelet decomposition algorithm, a general-purpose coarse-to-fine method for hierarchical fitting, based in this paper on an underlying multiresolution representation called dyadic splines. The algorithm requests input via a generic interval query mechanism, allowing a wide variety of non-local operations to be quickly implemented. The algorithm performs work proportionate to the tiny compressed output size, rather than to some arbitrarily high resolution that would otherwise be required, thus increasing performance by several orders of magnitude. We describe several design operations that are made tractable because of the progressive decomposition. Free-form pasting is a generalization of the traditional control-mesh edit, but for which the shape of the change is completely general and where the shape can be placed using a free-form deformation within the surface domain. Smoothing and roughening operations are enhanced so that an arbitrary loop in the domain specifies the area of effect. Finally, the sculpting effect of moving a tool shape along a path is simulated.

  19. Laboratory surface astrochemistry experiments

    SciTech Connect

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

    2015-05-15

    Although several research groups have studied the formation of H{sub 2} 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 H{sub 2}O 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 O{sub 2} 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.

  20. Surface imaging microscope

    NASA Astrophysics Data System (ADS)

    Rogala, Eric W.; Bankman, Isaac N.

    2008-04-01

    The three-dimensional shapes of microscopic objects are becoming increasingly important for battlespace CBRNE sensing. Potential applications of microscopic 3D shape observations include characterization of biological weapon particles and manufacturing of micromechanical components. Aerosol signatures of stand-off lidar systems, using elastic backscatter or polarization, are dictated by the aerosol particle shapes and sizes that must be well characterized in the lab. A low-cost, fast instrument for 3D surface shape microscopy will be a valuable point sensor for biological particle sensing applications. Both the cost and imaging durations of traditional techniques such as confocal microscopes, atomic force microscopes, and electron scanning microscopes are too high. We investigated the feasibility of a low-cost, fast interferometric technique for imaging the 3D surface shape of microscopic objects at frame rates limited only by the camera in the system. The system operates at two laser wavelengths producing two fringe images collected simultaneously by a digital camera, and a specialized algorithm we developed reconstructs the surface map of the microscopic object. The current implementation assembled to test the concept and develop the new 3D reconstruction algorithm has 0.25 micron resolution in the x and y directions, and about 0.1 micron accuracy in the z direction, as tested on a microscopic glass test object manufactured with etching techniques. We describe the interferometric instrument, present the reconstruction algorithm, and discuss further development.

  1. 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.

  2. 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

  3. Unoccupied surface states on GaP(111) surfaces

    NASA Astrophysics Data System (ADS)

    Hamza, Alex V.

    1993-06-01

    Unoccupied surface electronic states have been observed on GaP(111) surfaces by momentum- resolved inverse photoemission spectroscopy (IPES). On the GaP(111):P surface an unoccupied state is detected 1.2 eV above the Fermi level. This state is associated with Ga surface adatoms, since prolonged exposure to the incident electron beam removes this IPES feature and reduces the Ga/P ratio in Auger electron spectrum. Preferential photon absorption at 2.27 eV by this surface can be explained by promotion of an electron from the valence band maximum to the unoccupied surface state detected in this work.

  4. 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.

  5. Surface retention capacity calculation

    NASA Astrophysics Data System (ADS)

    David, Vaclav; Dostal, Tomas

    2010-05-01

    Flood wave transformation in the floodplain is the phenomenon which is researched within interdisciplinary project NIVA - Water Retention in Floodplains and Possibilities of Retention Capacity Increase. The project focuses on broad range of floodplain ecosystem services and mitigation of flooding is one of them. Despite main influence on flood wave transformation is due to flow retardation, retention in surface depressions within floodplain has been analyzed to get better overview of whole transformation process. Detail digital relief model (DRM) has been used for given purposes to be able to analyze terrain depressions volumes. The model was developed with use of stereophotogrammetric evaluation of airborne images with high resolution of 10 cm. It was essential for purposes of presented analysis not to apply pit removal routines which are often used for generation of DRM for hydrological modelling purposes. First, the methodology of analysis was prepared and tested on artificial surface. This surface was created using random raster generation, filtration and resampling with final resolution of 1000 x 1000 units and height of maximum 10 units above datum. The methodology itself is based on analysis of areas inundated by water at different elevation levels. Volume is than calculated for each depression using extraction of terrain elevations under corresponding water level. The method was then applied on the area of Lužnice River floodplain section to assess retention capacity of real floodplain. The floodplain had to be cut into sections perpendicular to main river orientation for analyses as the method was tested for square shaped area without any significant inclination. Results obtained by mentioned analysis are presented in this paper. Acknowledgement Presented research was accomplished within national project NIVA - Water Retention in Floodplains and Possibilities of Retention Capacity Increase, nr. QH82078. The project is funded by Ministry of Agriculture of

  6. 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.

  7. 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.

  8. 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. PMID:26382299

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Surface Nanobubbles Nucleate Microdroplets

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Lhuissier, Henri; Sun, Chao; Lohse, Detlef

    2014-04-01

    When a hydrophobic solid is in contact with water, surface nanobubbles often form at the interface. They have a lifetime many orders of magnitude longer than expected. Here, we show that they even withstand a temperature increase to temperatures close to the boiling point of bulk water; i.e., they do not nucleate larger bubbles ("superstability"). On the contrary, when the vapor-liquid contact line passes a nanobubble, a liquid film remains around it, which, after pinch-off, results in a microdroplet in which the nanobubbles continue to exist. Finally, the microdroplet evaporates and the nanobubble consequently bursts. Our results support that pinning plays a crucial role for nanobubble stability.

  14. Surface Nanobubble Stability

    NASA Astrophysics Data System (ADS)

    Seddon, James; Zandvliet, Harold; Lohse, Detlef

    2011-11-01

    We provide a model for the remarkable stability of surface nanobubbles to bulk dissolution. The key to the solution is that the gas in a nanobubble is of Knudsen type. This leads to the generation of a bulk liquid flow which effectively forces the diffusive gas to remain local. Our model predicts the presence of a vertical water jet immediately above a nanobubble, with an estimated speed of ~ 3 . 3 m / s , in good agreement with our experimental atomic force microscopy measurement of ~ 2 . 7 m / s . In addition, our model also predicts an upper bound for the size of nanobubbles, which is consistent with the available experimental data.

  15. Rainbow surface tension analysis.

    PubMed

    Adler, Charles L; Smith, Valen A; Haddad, Natalie M

    2008-03-31

    In this paper we outline a new all-optical non-contact technique for measurement of the surface tension of a Newtonian fluid. It is based on the accurate measurement of the spacing of the supernumerary fringes produced by the diffraction pattern of a laser beam transmitted through or reflected by a thin vertically-draining film of the liquid. We discuss the basic theory and application of this technique, and several issues which must be addressed before it can be used commercially. PMID:18542611

  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. 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

  20. 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.

  1. Surface tension of spherical drops from surface of tension

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  2. 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.

  3. 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.

  4. Europa's Salty Surface

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    1998-09-01

    Pictures of Jupiter's moon Europa taken by the Galileo spacecraft during the past couple of years have suggested to scientists that there is now, or was in the past, an ocean beneath the satellite's frozen crust. Now a team from the University of Hawaii, the Jet Propulsion Laboratory, the U.S. Geological Survey, and STI Inc. may have given us our first glimpse at the chemical composition of that ocean. Using data obtained by the Near-Infrared Mapping Spectrometer (NIMS) carried by Galileo, Thomas McCord (U. Hawaii) and his colleagues examined darker regions on the surface and compared the spacecraft data to numerous chemical compounds. Their analysis indicates that the darker areas are most likely composed of deposits of salty minerals such as sulfates and carbonates. McCord and his associates believe that the minerals formed when ocean water erupted onto the surface and then evaporated, leaving behind salty deposits. They hope that further research will allow them to determine the chemical composition of Europa's hidden ocean and assess the likelihood that life could have formed in it.

  5. Nanoscale surface photoreactions

    NASA Astrophysics Data System (ADS)

    Wadsworth, Garrett Austin

    Subnanometer-scale properties of molecules and materials have become extremely important to the development of nanoscale and molecular electronics devices, including advanced biological and chemical sensors. The energies (i.e., wavelengths) at which the LSPRs of individual nanoparticles are excited varies depending on their size, thickness, and shape, all of which can be controlled synthetically. Photon-coupled scanning tunneling microscopy uses a total internal reflection scheme to couple light into a tunneling junction, generating this specific LSPR in individual Au and Ag nanoprisms. By controlling and coupling this specific excitation to molecular assemblies, the effective photoreactivities and photoconductances of organic molecules can be measured and manipulated. Nanoparticle synthesis methods were developed to produce nanoprisms with appropriate dimensions and homogeneity. Functionalization of the sample surface using alkanedithiols and p-terphenyl-4,4"-dithiol enabled the adsorption dispersion of nanoprisms onto substrates with high density yet minimal stacking. Insertion into self-assembled monolayers was used to arrange single molecules on Au{111} and Ag{111} nanoprisms for selective surface plasmonic enhancement. Scanning tunneling microscopy measurements were collected for molecules adsorbed on the dispersed nanoprisms. Photon STM will be used to monitor the photoactivities of molecules on these substrates, such as photocurrent, photoconductance, and photoreaction.

  6. 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.

  7. 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.

  8. 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.

  9. Surface chemistry of palladium

    SciTech Connect

    Gentle, T.M.

    1984-05-01

    Several classes of catalytically important molecules on Pd single crystals were studied. Influence of surface structure and composition on reactions involving formation and scission of carbon-carbon and carbon-hydrogen bonds was investigated under uhv conditions on single crystals and higher pressures on polycrystalline films. Reactions of acetylene on Pd(111), Pd(100), and Pd(110) were studied using thermal desorption spectroscopy, chemical displacement reactions, and isotopic labeling techniques. Pd single crystals catalyzes trimerization to benzene, hydrogenation to ethylene, and hydrosilation with trimethylsilane. Several atoms such as Si, P, S, and Cl have a profound influence on the catalysis. Single-crystal Pd surfaces catalyzes the dehydrogenation of organosilanes; silacyclohexane chemisorbed on Pd(110) underwent dehydrogenation upon thermal desorption to form silabenzene. Desulfurization products were observed in the thermal desorption spectra chemisorbed thiophene, 3-methylthiophene, and 2,5-dimethylthiophene. Mechanisms of carbon-hydrogen bond scission were investigated for a variety of methyl-substituted benzenes, revealing some degree of regiospecificity in C-H bond scission. Several reactions of unsaturated hydrocarbons were also investigated at higher pressures (10/sup -2/ torr) on polycrystalline Pd films.

  10. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  12. 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.

  13. 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.

  14. 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...

  15. Surface engineering with soft matter

    NASA Astrophysics Data System (ADS)

    Genzer, Jan

    2005-03-01

    In my presentation, I will outline several novel strategies facilitating the generation of functional polymeric surfaces. In particular, I will present and discuss simple methodologies leading to the formation of complex surface assemblies of surface-tethered polymers with continuous variation of physico- chemical properties (e.g., wettability, molecular weight, grafting density, composition). I will illustrate how these grafted “gradient” surfaces can be utilized to control the spatial distribution of adsorbates, such as nanoparticles and proteins, and administer the proliferation of living cells on the surfaces. Furthermore, I will illustrate how flexible elastomeric networks can be utilized to tailor the grafting density of oligomers or polymers, create responsive (``smart'') surfaces, and generate topographically corrugated surfaces comprising multidimensional cascades of wrinkles. Application of these wrinkled surfaces for material assembly will also be demonstrated.

  16. 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.

  17. The surface science of nanocrystals.

    PubMed

    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. PMID:26796733

  18. 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.

  19. 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. PMID:25787219

  20. Nanotextured surfaces for surface enhanced Raman spectroscopy and sensors

    NASA Astrophysics Data System (ADS)

    Balčytis, Armandas; JuodkazytÄ--, Jurga; Seniutinas, Gediminas; Li, Xijun; Niaura, Gediminas; Juodkazis, Saulius

    2016-03-01

    Nanotextured surfaces which have surface features spanning 10-100 nm in length and height scales are among the most promising for surface enhanced Raman scattering/spectroscopy (SERS). Randomness of the feature sizes and surface morphology of such sensors brings an added benefit of spectrally broadband action and, consequently, augmented SERS intensity. Surfaces which are most promising for high sensitivity yet cost efficient for large scale production are overviewed with black CuO, which is made by chemical oxidation of Cu foil, as a representative example. Application potential and challenges to establishing quantitative SERS measurements are outlined.

  1. 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.

  2. Surface instabilities and nuclear multifragmentation

    SciTech Connect

    Moretto, L.G.; Tso, K.; Colonna, N.; Wozniak, G.J.

    1992-03-01

    Central heavy-ion collisions, as described by a Boltzman-Nordheim-Vlasov calculation, form nuclear disks that break up into several fragments due to surface instabilities of the Rayleigh-Taylor kind. We demonstrate that a sheet of liquid, nuclear or otherwise, stable in the limit of infinitely sharp surfaces, becomes unstable due to surface-surface interactions. The onset of this instability is determined analytically. The relevance of these instabilities to nuclear multifragmentation is discussed.

  3. Method for lubricating contacting surfaces

    DOEpatents

    Dugger, Michael T.; Ohlhausen, James A.; Asay, David B.; Kim, Seong H.

    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.

  4. Measurement of surface velocity fields

    NASA Technical Reports Server (NTRS)

    Mann, J. A., Jr.

    1979-01-01

    A new technique for measuring surface velocity fields is briefly described. It determines the surface velocity vector as a function of location and time by the analysis of thermal fluctuations of the surface profile in a small domain around the point of interest. The apparatus now being constructed will be used in a series of experiments involving flow fields established by temperature gradients imposed along a surface.

  5. 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).

  6. 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.

  7. Surface Acoustic Wave Microfluidics

    NASA Astrophysics Data System (ADS)

    Yeo, Leslie Y.; Friend, James R.

    2014-01-01

    Fluid manipulations at the microscale and beyond are powerfully enabled through the use of 10-1,000-MHz acoustic waves. A superior alternative in many cases to other microfluidic actuation techniques, such high-frequency acoustics is almost universally produced by surface acoustic wave devices that employ electromechanical transduction in wafer-scale or thin-film piezoelectric media to generate the kinetic energy needed to transport and manipulate fluids placed in adjacent microfluidic structures. These waves are responsible for a diverse range of complex fluid transport phenomena - from interfacial fluid vibration and drop and confined fluid transport to jetting and atomization - underlying a flourishing research literature spanning fundamental fluid physics to chip-scale engineering applications. We highlight some of this literature to provide the reader with a historical basis, routes for more detailed study, and an impression of the field's future directions.

  8. 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.

  9. Surface nanobubbles nucleate microdroplets.

    PubMed

    Zhang, Xuehua; Lhuissier, Henri; Sun, Chao; Lohse, Detlef

    2014-04-11

    When a hydrophobic solid is in contact with water, surface nanobubbles often form at the interface. They have a lifetime many orders of magnitude longer than expected. Here, we show that they even withstand a temperature increase to temperatures close to the boiling point of bulk water; i.e., they do not nucleate larger bubbles ("superstability"). On the contrary, when the vapor-liquid contact line passes a nanobubble, a liquid film remains around it, which, after pinch-off, results in a microdroplet in which the nanobubbles continue to exist. Finally, the microdroplet evaporates and the nanobubble consequently bursts. Our results support that pinning plays a crucial role for nanobubble stability. PMID:24765973

  10. Tunable surface plasmon devices

    DOEpatents

    Shaner, Eric A.; Wasserman, Daniel

    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.

  11. 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.

  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. Near surface analysis

    NASA Technical Reports Server (NTRS)

    Johnson, Gordon G.

    1993-01-01

    This is a study to assist in the understanding of earth near surface structure. Higher order moments are used to detect the density distribution as well as to seek patterns found in geological structures. It is shown how higher order moments at points outside a mass structure are determined as well as how to recover the mass distribution from the higher order moments. It is interesting to note that the first moment at a point P outside the mass structure, V(sub O)(P), is the entire mass and the second moment, V(sub 1)(P), is the potential at P due to the mass structure. Usually only the mass and the potential function are used to determine the density distribution in a body. An infinite function sequence (V(sub n)(P))(sub n=0)(sup infinity) is required to uniquely determine the density distribution.

  14. 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.

  15. 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

  16. 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.

  17. 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

    2014-01-01

    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

  18. 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

  19. Surface characteristics and bioactivity of an anodized titanium surface

    PubMed Central

    Kim, Kyul; Lee, Bo-Ah; Piao, Xing-Hui; Chung, Hyun-Ju

    2013-01-01

    Purpose The aim of this study was to evaluate the surface properties and biological response of an anodized titanium surface by cell proliferation and alkaline phosphatase activity analysis. Methods Commercial pure titanium (Ti) disks were prepared. The samples were divided into an untreated machined Ti group and anodized Ti group. The anodization of cp-Ti was formed using a constant voltage of 270 V for 60 seconds. The surface properties were evaluated using scanning electron microscopy, X-ray photoelectron spectroscopy, and an image analyzing microscope. The surface roughness was evaluated by atomic force microscopy and a profilometer. The contact angle and surface energy were analyzed. Cell adhesion, cell proliferation, and alkaline phosphatase activity were evaluated using mouse MC3T3-E1 cells. Results The anodized Ti group had a more porous and thicker layer on its surface. The surface roughness of the two groups measured by the profilometer showed no significant difference (P>0.001). The anodized Ti dioxide (TiO2) surface exhibited better corrosion resistance and showed a significantly lower contact angle than the machined Ti surface (P>0.001). Although there was no significant difference in the cell viability between the two groups (P>0.001), the anodized TiO2 surface showed significantly enhanced alkaline phosphatase activity (P<0.001). Conclusions These results suggest that the surface modification of Ti by anodic oxidation improved the osteogenic response of the osteoblast cells. PMID:24040573

  20. 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.

  1. 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.

  2. Volcanic Surface Textures

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 16 June 2003

    The platy surface texture observed in this THEMIS image of the vast plains southeast of the volcano Elysium Mons likely formed by very fluid cooling lava. Variations in the surface texture may reflect different cooling or flow rates of the lava. The lack of any large impact craters also points to a relatively young age for these volcanic materials. The two largest impact craters occur in the higher plateau unit indicating that these materials are older.

    Image information: VIS instrument. Latitude 11.6, Longitude 182.4 East (177.6 West). 19 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.

  3. Surface-potential decay due to surface conduction

    NASA Astrophysics Data System (ADS)

    Crisci, A.; Gosse, B.; Gosse, J.-P.; Ollier-Duréault, V.

    1998-10-01

    The time dependence of the surface potential of an insulating material is theoretically investigated in the case of simultaneous surface and volume ohmic conduction. When the material presents a constant surface conductivity, the first part of the decrease with time of the surface potential is strongly influenced by the initial distribution of charges and cannot be used to determine the surface conductivity. On the other hand, at rather long times after the surface has been charged, the potential of the surface follows an exponential variation with time, the expression of the corresponding time constant is given in different cases. This model is found in good agreement with experiments performed with photo-oxidized epoxy resins placed in a humid atmosphere.

  4. 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.

  5. Free surface properties of 3-5 compound semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Kahn, A.

    1980-06-01

    Studies of free compound semiconductor surfaces as well as gas-solid and metal-solid interaction are summarized. An experimental and theoretical analysis of the GaAs(110) surface reconstruction was conducted and applied to three additional compounds: InSb, InP and ZnTe. Attempts were made to relate the type and the magnitude of the surface reconstruction of these materials to the covalent-ionic character of the bonding. Knowledge of the atomic reconstructions of these surfaces was used to investigate the reactivity of semiconductor surfaces (GaAs(110)) with gas (oxygen) and metal (aluminum) atoms. These multicomponent systems are at the center of the author's essays to understand the chemistry of these surfaces and its relationship with their atomic reconstruction. Using Low Energy Electron Diffraction (LEED) as the principal tool to investigation, structural information has been obtained which correlates chemical and electronic information obtained by other surface analysis techniques.

  6. Nanowetting of rough superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Lamb, R. N.; Cookson, D. J.

    2007-12-01

    Small angle x-ray scattering has been used to investigate the in situ immersive wetting of ultrarough surfaces which exhibit superhydrophobicity with extreme water contact angle (θA=169°). Reduced scattering contrast observed from rough surfaces when partially or totally wetted reveals significant physical differences between superhydrophobic surfaces not otherwise apparent from conventional contact angle measurements.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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. PMID:20616392

  14. 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.

  15. 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.

  16. Microbial surface thermodynamics and applications.

    PubMed

    Strevett, Keith A; Chen, Gang

    2003-06-01

    Microbial surface thermodynamics is the reflection of microbial physicochemical and biological characteristics and it bridges micro-scale structures with macro-scale biological functions. Microbial surface thermodynamics is theoretically based on colloid surface thermodynamics using the classical theory of colloidal stability, Derjauin-Landau-Verwey-Overbeek (DLVO) theory. An extended DLVO theory is applied to for the hydration forces not considered in the classical DLVO theory. Herein, a review of current application of microbial surface thermodynamic theory is presented. Microbial surface thermodynamic theory is the fundamental theory in interpreting microbial hydrophilicity or hydrophobicity, microbial attachment, and microbial biofilm development. PMID:12837508

  17. The surface layer for free-surface turbulent flows

    NASA Astrophysics Data System (ADS)

    Shen, Lian; Zhang, Xiang; Yue, Dick K. P.; Triantafyllou, George S.

    1999-05-01

    Direct numerical simulation (DNS) is used to examine low Froude number free-surface turbulence (FST) over a two-dimensional mean shear flow. The Navier Stokes equations are solved using a finite-difference scheme with a grid resolution of 1283. Twenty separate simulations are conducted to calculate the statistics of the flow. Based on the velocity deficit and the vertical extent of the shear of the mean flow, the Reynolds number is 1000 and the Froude number is 0.7. We identify conceptually and numerically the surface layer, which is a thin region adjacent to the free surface characterized by fast variations of the horizontal vorticity components. This surface layer is caused by the dynamic zero-stress boundary conditions at the free surface and lies inside a thicker blockage (or ‘source’) layer, which is due to the kinematic boundary condition at the free surface. The importance of the outer blockage layer is manifested mainly in the redistribution of the turbulence intensity, i.e. in the increase of the horizontal velocity fluctuations at the expense of the vertical velocity fluctuation. A prominent feature of FST is vortex connections to the free surface which occur inside the surface layer. It is found that as hairpin-shaped vortex structures approach the free surface, their ‘head’ part is dissipated quickly in the surface layer, while the two ‘legs’ connect almost perpendicularly to the free surface. Analysis of the evolution of surface-normal vorticity based on vortex surface-inclination angle shows that both dissipation and stretching decrease dramatically after connection. As a result, vortex structures connected to the free surface are persistent and decay slowly relative to non-connected vorticities. The effects of surface and blockage layers on the turbulence statistics of length scales, Reynolds-stress balance, and enstrophy dynamics are examined, which elucidate clearly the different turbulence mechanisms operating in the respective near-surface

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Scattering from a random surface

    SciTech Connect

    Abarbanel, H.D.I.

    1980-11-01

    We give a formulation of the problem of propagation of scalar waves over a random surface. By a judicious choice of variables we are able to show that this situation is equivalent to propagation of these waves through a medium of random fluctuations with fluctuating source and receiver. The wave equation in the new coordinates has an additional term, the fluctuation operator, which depends on derivatives of the surface in space and time. An expansion in the fluctuation operator is given which guarantees the desired boundary conditions at every order. We treat both the cases where the surface is time dependent, such as the sea surface, or fixed in time. Also discussed is the situation where the source and receiver lie between the random surface and another, possibly also random, surface. In detail we consider acoustic waves for which the surfaces are pressure release. The method is directly applicable to electromagnetic waves and other boundary conditions.

  3. Bronze: The other surfacing material

    SciTech Connect

    Mertes, A.

    1995-09-01

    When a surfacing application requires resistance to corrosion, abrasion, friction and oxidation, the first welding materials that come to mind are iron, cobalt, nickel-based alloys and the carbide particle materials. Not as prominent are the copper-alloy surfacing electrodes and filler metals, yet they play an important role in resisting corrosion, erosion, cavitation, and metal-to-metal wear. Generally, the copper alloys that are used for surfacing fall into four copper-alloy families. They are: copper-zinc, copper-silicon, copper-tin and copper-aluminum. The copper-zinc alloys are used for very soft bearing surfaces and mild corrosion; the copper-silicon alloys for corrosion-resistant surfaces; copper-tin alloys for soft bearing and corrosion-resistant surfaces; and the copper-aluminum alloys for bearings of higher hardness and corrosion, erosion, cavitation and wear-resistant surfaces.

  4. 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.

  5. Quantification of surface amorphous content using dispersive surface energy: the concept of effective amorphous surface area.

    PubMed

    Brum, Jeffrey; Burnett, Daniel

    2011-09-01

    We investigate the use of dispersive surface energy in quantifying surface amorphous content, and the concept of effective amorphous surface area is introduced. An equation is introduced employing the linear combination of surface area normalized square root dispersive surface energy terms. This equation is effective in generating calibration curves when crystalline and amorphous references are used. Inverse gas chromatography is used to generate dispersive surface energy values. Two systems are investigated, and in both cases surface energy data collected for physical mixture samples comprised of amorphous and crystalline references fits the predicted response with good accuracy. Surface amorphous content of processed lactose samples is quantified using the calibration curve, and interpreted within the context of effective amorphous surface area. Data for bulk amorphous content is also utilized to generate a thorough picture of how disorder is distributed throughout the particle. An approach to quantifying surface amorphous content using dispersive surface energy is presented. Quantification is achieved by equating results to an effective amorphous surface area based on reference crystalline, and amorphous materials. PMID:21725707

  6. 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

  7. 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

  8. Surface Mounted Neutron Generators

    NASA Astrophysics Data System (ADS)

    Elizondo-Decanini, Juan M.

    2012-10-01

    A deuterium-tritium (DT) base reaction pulsed neutron generator packaged in a flat computer chip shape of 1.54 cm (0.600 in) wide by 3.175 cm (1.25 in) length and 0.3 cm (0.120 in) thick has been successfully demonstrated to produce 14 MeV neutrons at a rate of 10^9 neutrons per second. The neutron generator is based on a deuterium ion beam accelerated to impact a tritium loaded target. The accelerating voltage is in the 15 to 20 kV in a 3 mm (0.120 in) gap, the ion beam is shaped by using a lens design to produce a flat ion beam that conforms to the flat rectangular target. The ion source is a simple surface mounted deuterium filled titanium film with a fused gap that operates at a current-voltage design to release the deuterium during a pulse length of about 1 μs. We present the general description of the working prototypes, which we have labeled the ``NEUTRISTOR.''[4pt] Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration. Work funded by the LDRD office.

  9. Arsia Mons Surface Flow

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Today's VIS image of lava flows south of Arsia Mons shows a broad, rough surfaced flow (brighter in image). The brighter flow splits at the bottom and then rejoins again, leaving a window of older flow visible. Note how the flows overlap at the bottom of the image.

    Image information: VIS instrument. Latitude -22.6, Longitude 239.7 East (120.3 West). 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.

  10. Ariel's Densely Pitted Surface

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This mosaic of the four highest-resolution images of Ariel represents the most detailed Voyager 2 picture of this satellite of Uranus. The images were taken through the clear filter of Voyager's narrow-angle camera on Jan. 24, 1986, at a distance of about 130,000 kilometers (80,000 miles). Ariel is about 1,200 km (750 mi) in diameter; the resolution here is 2.4 km (1.5 mi). Much of Ariel's surface is densely pitted with craters 5 to 10 km (3 to 6 mi) across. These craters are close to the threshold of detection in this picture. Numerous valleys and fault scarps crisscross the highly pitted terrain. Voyager scientists believe the valleys have formed over down-dropped fault blocks (graben); apparently, extensive faulting has occurred as a result of expansion and stretching of Ariel's crust. The largest fault valleys, near the terminator at right, as well as a smooth region near the center of this image, have been partly filled with deposits that are younger and less heavily cratered than the pitted terrain. Narrow, somewhat sinuous scarps and valleys have been formed, in turn, in these young deposits. It is not yet clear whether these sinuous features have been formed by faulting or by the flow of fluids.

    JPL manages the Voyager project for NASA's Office of Space Science.

  11. Internal Surface Water Flows

    USGS Publications Warehouse

    Murray, Mitchell H.

    1999-01-01

    Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making.The U.S. Geological Survey (USGS) provides scientitic information as part of the South Florida Ecosystem Restoration Program. The USGS began its own project, called the South Florida Ecosystem Project in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Historical changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system with canals, levees, and pumping stations. These structures have altered the hydology of the Everglades ecosystem on both coastal and interior lands. Surface-water flows in a direction south of Lake Okeechobee have been regulated by an extensive canal network, begun in the 1940's, to provide for drainage, flood control, saltwater intrusion control, agricultural requirements, and various environmental needs. Much of the development and subsequent monitoring of canal and river discharge south of Lake Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has been placed on providing a more accurate water budget for internal canal flows.

  12. Crawling on directional surfaces

    NASA Astrophysics Data System (ADS)

    Gidoni, P.; Noselli, G.; DeSimone, A.

    2014-05-01

    In this paper we study crawling locomotion based on directional frictional interactions, namely, frictional forces that are sensitive to the sign of the sliding velocity. Surface interactions of this type are common in biology, where they arise from the presence of inclined hairs or scales at the crawler/substrate interface, leading to low resistance when sliding 'along the grain', and high resistance when sliding 'against the grain'. This asymmetry can be exploited for locomotion, in a way analogous to what is done in cross-country skiing (classic style, diagonal stride). We focus on a model system, namely, a continuous one-dimensional crawler and provide a detailed study of the motion resulting from several strategies of shape change. In particular, we provide explicit formulae for the displacements attainable with reciprocal extensions and contractions (breathing), or through the propagation of extension or contraction waves. We believe that our results will prove particularly helpful for the study of biological crawling motility and for the design of bio-mimetic crawling robots.

  13. Designing durable icephobic surfaces.

    PubMed

    Golovin, Kevin; Kobaku, Sai P R; Lee, Duck Hyun; DiLoreto, Edward T; Mabry, Joseph M; Tuteja, Anish

    2016-03-01

    Ice accretion has a negative impact on critical infrastructure, as well as a range of commercial and residential activities. Icephobic surfaces are defined by an ice adhesion strength τice < 100 kPa. However, the passive removal of ice requires much lower values of τice, such as on airplane wings or power lines (τice < 20 kPa). Such low τice values are scarcely reported, and robust coatings that maintain these low values have not been reported previously. We show that, irrespective of material chemistry, by tailoring the cross-link density of different elastomeric coatings and by enabling interfacial slippage, it is possible to systematically design coatings with extremely low ice adhesion (τice < 0.2 kPa). These newfound mechanisms allow for the rational design of icephobic coatings with virtually any desired ice adhesion strength. By using these mechanisms, we fabricate extremely durable coatings that maintain τice < 10 kPa after severe mechanical abrasion, acid/base exposure, 100 icing/deicing cycles, thermal cycling, accelerated corrosion, and exposure to Michigan wintery conditions over several months. PMID:26998520

  14. Surface mount component jig

    DOEpatents

    Kronberg, James W.

    1990-08-07

    A device for bending and trimming the pins of a dual-inline-package component and the like for surface mounting rather than through mounting to a circuit board comprises, in a first part, in pin cutter astride a holder having a recess for holding the component, a first spring therebetween, and, in a second part, two flat members pivotally interconnected by a hinge and urged to an upward peaked position from a downward peaked position by a second spring. As a downward force is applied to the pin cutter it urges the holder downward, assisted by the first spring and a pair of ridges riding on shoulders of the holder, to carry the component against the upward peaked flat members which guide the pins outwardly. As the holder continues downwardly, the flat members pivot to the downward peaked position bending the pins upwardly against the sides of the holder. When the downward movement is met with sufficient resistance, the ridges of the pin cutter ride over the holder's shoulders to continue downward to cut any excess length of pin.

  15. Surface Erosion and Flow

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 7 April 2003

    The mottled surface texture and flow features observed in this THEMIS 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.

    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.

    Image information: VIS instrument. Latitude 45.3, Longitude 48.8 East (311.2 West). 19 meter/pixel resolution.

  16. Designing durable icephobic surfaces

    PubMed Central

    Golovin, Kevin; Kobaku, Sai P. R.; Lee, Duck Hyun; DiLoreto, Edward T.; Mabry, Joseph M.; Tuteja, Anish

    2016-01-01

    Ice accretion has a negative impact on critical infrastructure, as well as a range of commercial and residential activities. Icephobic surfaces are defined by an ice adhesion strength τice < 100 kPa. However, the passive removal of ice requires much lower values of τice, such as on airplane wings or power lines (τice < 20 kPa). Such low τice values are scarcely reported, and robust coatings that maintain these low values have not been reported previously. We show that, irrespective of material chemistry, by tailoring the cross-link density of different elastomeric coatings and by enabling interfacial slippage, it is possible to systematically design coatings with extremely low ice adhesion (τice < 0.2 kPa). These newfound mechanisms allow for the rational design of icephobic coatings with virtually any desired ice adhesion strength. By using these mechanisms, we fabricate extremely durable coatings that maintain τice < 10 kPa after severe mechanical abrasion, acid/base exposure, 100 icing/deicing cycles, thermal cycling, accelerated corrosion, and exposure to Michigan wintery conditions over several months. PMID:26998520

  17. 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

  18. 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.

  19. 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. PMID:17801231

  20. 77 FR 50165 - Escape and Evacuation Plans for Surface Coal Mines, Surface Facilities and Surface Work Areas of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... and Surface Work Areas of Underground Coal Mines AGENCY: Mine Safety and Health Administration, Labor... surface coal mines, surface facilities and surface work areas of underground coal mines. MSHA is... Administration. Title: Escape and Evacuation Plans for Surface Coal Mines, Surface Facilities ] and Surface...

  1. Tunable superomniphobic surfaces for sorting droplets by surface tension.

    PubMed

    Movafaghi, S; Wang, W; Metzger, A; Williams, D D; Williams, J D; Kota, A K

    2016-08-16

    We utilized tunable superomniphobic surfaces with flower-like TiO2 nanostructures to fabricate a simple device with precisely tailored surface energy domains that, for the first time, can sort droplets by surface tension. We envision that our methodology for droplet sorting will enable inexpensive and energy-efficient analytical devices for personalized point-of-care diagnostic platforms, lab-on-a-chip systems, biochemical assays and biosensors. PMID:27412084

  2. Surface Modification of Intraocular Lenses

    PubMed Central

    Huang, Qi; Cheng, George Pak-Man; Chiu, Kin; Wang, Gui-Qin

    2016-01-01

    Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs). Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO2, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs. PMID:26830993

  3. Adhesion behaviors on superhydrophobic surfaces.

    PubMed

    Zhu, Huan; Guo, Zhiguang; Liu, Weimin

    2014-04-18

    The adhesion behaviors of superhydrophobic surfaces have become an emerging topic to researchers in various fields as a vital step in the interactions between materials and organisms/materials. Controlling the chemical compositions and topological structures via various methods or technologies is essential to fabricate and modulate different adhesion properties, such as low-adhesion, high-adhesion and anisotropic adhesion on superhydrophobic surfaces. We summarize the recent developments in both natural superhydrophobic surfaces and artificial superhydrophobic surfaces with various adhesions and also pay attention to superhydrophobic surfaces switching between low- and high-adhesion. The methods to regulate or translate the adhesion of superhydrophobic surfaces can be considered from two perspectives. One is to control the chemical composition and change the surface geometric structure on the surfaces, respectively or simultaneously. The other is to provide external stimulations to induce transitions, which is the most common method for obtaining switchable adhesions. Additionally, adhesion behaviors on solid-solid interfaces, such as the behaviors of cells, bacteria, biomolecules and icing on superhydrophobic surfaces are also noticeable and controversial. This review is aimed at giving a brief and crucial overview of adhesion behaviors on superhydrophobic surfaces. PMID:24575424

  4. Topographic characterization of glazed surfaces

    NASA Astrophysics Data System (ADS)

    Fröberg, Linda; Hupa, Leena

    2008-01-01

    Detailed characterization of surface microstructure, i.e. phase composition and surface geometry, has become an important criterion of glazed ceramics. Topographic characterization is an important parameter in, e.g. estimating the influence of additional films on the average roughness of a surface. Also, the microscaled and nanoscaled roughnesses correlate with the cleanability and the self-cleaning properties of the surfaces. In this work the surface geometry of several matte glazes were described by topography and roughness as given by whitelight confocal microscopy and atomic force microscopy. Different measuring parameters were compared to justify the usefulness of the techniques in giving a comprehensive description of the surface microstructure. The results suggest that confocal microscopy is well suited for giving reliable topographical parameters for matte surfaces with microscaled crystals in the surfaces. Atomic force microscopy was better suited for smooth surfaces or for describing the local topographic parameters of closely limited areas, e.g. the surroundings of separate crystals in the surface.

  5. Advances in surfaces and osseointegration in implantology. Biomimetic surfaces

    PubMed Central

    Albertini, Matteo; Fernandez-Yague, Marc; Lázaro, Pedro; Herrero-Climent, Mariano; Bullon, Pedro; Gil, Francisco-Javier

    2015-01-01

    The present work is a revision of the processes occurring in osseointegration of titanium dental implants according to different types of surfaces -namely, polished surfaces, rough surfaces obtained from subtraction methods, as well as the new hydroxyapatite biomimetic surfaces obtained from thermochemical processes. Hydroxyapatite’s high plasma-projection temperatures have proven to prevent the formation of crystalline apatite on the titanium dental implant, but lead to the formation of amorphous calcium phosphate (i.e., with no crystal structure) instead. This layer produce some osseointegration yet the calcium phosphate layer will eventually dissolve and leave a gap between the bone and the dental implant, thus leading to osseointegration failure due to bacterial colonization. A new surface -recently obtained by thermochemical processes- produces, by crystallization, a layer of apatite with the same mineral content as human bone that is chemically bonded to the titanium surface. Osseointegration speed was tested by means of minipigs, showing bone formation after 3 to 4 weeks, with the security that a dental implant can be loaded. This surface can be an excellent candidate for immediate or early loading procedures. Key words:Dental implants, implants surfaces, osseointegration, biomimetics surfaces. PMID:25662555

  6. Urban aerosol effects on surface insolation and surface temperature

    NASA Astrophysics Data System (ADS)

    Jin, M.; Burian, S. J.; Remer, L. A.; Shepherd, M. J.

    2007-12-01

    Urban aerosol particulates may play a fundamental role in urban microclimates and city-generated mesoscale circulations via its effects on energy balance of the surface. Key questions that need to be addressed include: (1) How do these particles affect the amount of solar energy reaching the surface and resulting surface temperature? (2) Is the effect the same in all cities? and (3) How does it vary from city to city? Using NASA AERONET in-situ observations, a radiative transfer model, and a regional climate mode (MM5), we assess aerosol effects on surface insolation and surf ace temperature for dense urban-polluted regions. Two big cities, one in a developing country (Beijing, P.R. China) and another in developed country (New York City, USA), are selected for inter-comparison. The study reveals that aerosol effects on surface temperature depends largely on aerosols' optical and chemical properties as well as atmosphere and land surface conditions, such as humidity and land cover. Therefore, the actual magnitudes of aerosol effects differ from city to city. Aerosol measurements from AERONET show both average and extreme cases for aerosol impacts on surface insolation. In general, aerosols reduce surface insolation by 30Wm-2. Nevertheless, in extreme cases, such reduction can exceed 100 Wm-2. Consequently, this reduces surface skin temperature 2-10C in an urban environment.

  7. Role of surface temperature in fluorocarbon plasma-surface interactions

    SciTech Connect

    Nelson, Caleb T.; Overzet, Lawrence J.; Goeckner, Matthew J.

    2012-07-15

    This article examines plasma-surface reaction channels and the effect of surface temperature on the magnitude of those channels. Neutral species CF{sub 4}, C{sub 2}F{sub 6}, and C{sub 3}F{sub 8} are produced on surfaces. The magnitude of the production channel increases with surface temperature for all species, but favors higher mass species as the temperature is elevated. Additionally, the production rate of CF{sub 2} increases by a factor of 5 as the surface temperature is raised from 25 Degree-Sign C to 200 Degree-Sign C. Fluorine density, on the other hand, does not change as a function of either surface temperature or position outside of the plasma glow. This indicates that fluorine addition in the gas-phase is not a dominant reaction. Heating reactors can result in higher densities of depositing radical species, resulting in increased deposition rates on cooled substrates. Finally, the sticking probability of the depositing free radical species does not change as a function of surface temperature. Instead, the surface temperature acts together with an etchant species (possibly fluorine) to elevate desorption rates on that surface at temperatures lower than those required for unassisted thermal desorption.

  8. Airport Surface Network Architecture Definition

    NASA Technical Reports Server (NTRS)

    Nguyen, Thanh C.; Eddy, Wesley M.; Bretmersky, Steven C.; Lawas-Grodek, Fran; Ellis, Brenda L.

    2006-01-01

    Currently, airport surface communications are fragmented across multiple types of systems. These communication systems for airport operations at most airports today are based dedicated and separate architectures that cannot support system-wide interoperability and information sharing. The requirements placed upon the Communications, Navigation, and Surveillance (CNS) systems in airports are rapidly growing and integration is urgently needed if the future vision of the National Airspace System (NAS) and the Next Generation Air Transportation System (NGATS) 2025 concept are to be realized. To address this and other problems such as airport surface congestion, the Space Based Technologies Project s Surface ICNS Network Architecture team at NASA Glenn Research Center has assessed airport surface communications requirements, analyzed existing and future surface applications, and defined a set of architecture functions that will help design a scalable, reliable and flexible surface network architecture to meet the current and future needs of airport operations. This paper describes the systems approach or methodology to networking that was employed to assess airport surface communications requirements, analyze applications, and to define the surface network architecture functions as the building blocks or components of the network. The systems approach used for defining these functions is relatively new to networking. It is viewing the surface network, along with its environment (everything that the surface network interacts with or impacts), as a system. Associated with this system are sets of services that are offered by the network to the rest of the system. Therefore, the surface network is considered as part of the larger system (such as the NAS), with interactions and dependencies between the surface network and its users, applications, and devices. The surface network architecture includes components such as addressing/routing, network management, network

  9. DNA computing on surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Qinghua; Wang, Liman; Frutos, Anthony G.; Condon, Anne E.; Corn, Robert M.; Smith, Lloyd M.

    2000-01-01

    DNA computing was proposed as a means of solving a class of intractable computational problems in which the computing time can grow exponentially with problem size (the `NP-complete' or non-deterministic polynomial time complete problems). The principle of the technique has been demonstrated experimentally for a simple example of the hamiltonian path problem (in this case, finding an airline flight path between several cities, such that each city is visited only once). DNA computational approaches to the solution of other problems have also been investigated. One technique involves the immobilization and manipulation of combinatorial mixtures of DNA on a support. A set of DNA molecules encoding all candidate solutions to the computational problem of interest is synthesized and attached to the surface. Successive cycles of hybridization operations and exonuclease digestion are used to identify and eliminate those members of the set that are not solutions. Upon completion of all the multi-step cycles, the solution to the computational problem is identified using a polymerase chain reaction to amplify the remaining molecules, which are then hybridized to an addressed array. The advantages of this approach are its scalability and potential to be automated (the use of solid-phase formats simplifies the complex repetitive chemical processes, as has been demonstrated in DNA and protein synthesis). Here we report the use of this method to solve a NP-complete problem. We consider a small example of the satisfiability problem (SAT), in which the values of a set of boolean variables satisfying certain logical constraints are determined.

  10. Simulation of surface processes.

    PubMed

    Jónsson, Hannes

    2011-01-18

    Computer simulations of surface processes can reveal unexpected insight regarding atomic-scale structure and transitions. Here, the strengths and weaknesses of some commonly used approaches are reviewed as well as promising avenues for improvements. The electronic degrees of freedom are usually described by gradient-dependent functionals within Kohn-Sham density functional theory. Although this level of theory has been remarkably successful in numerous studies, several important problems require a more accurate theoretical description. It is important to develop new tools to make it possible to study, for example, localized defect states and band gaps in large and complex systems. Preliminary results presented here show that orbital density-dependent functionals provide a promising avenue, but they require the development of new numerical methods and substantial changes to codes designed for Kohn-Sham density functional theory. The nuclear degrees of freedom can, in most cases, be described by the classical equations of motion; however, they still pose a significant challenge, because the time scale of interesting transitions, which typically involve substantial free energy barriers, is much longer than the time scale of vibrations--often 10 orders of magnitude. Therefore, simulation of diffusion, structural annealing, and chemical reactions cannot be achieved with direct simulation of the classical dynamics. Alternative approaches are needed. One such approach is transition state theory as implemented in the adaptive kinetic Monte Carlo algorithm, which, thus far, has relied on the harmonic approximation but could be extended and made applicable to systems with rougher energy landscape and transitions through quantum mechanical tunneling. PMID:21199939

  11. Materials surface contamination analysis

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Arendale, William F.

    1992-01-01

    The original research objective was to demonstrate the ability of optical fiber spectrometry to determine contamination levels on solid rocket motor cases in order to identify surface conditions which may result in poor bonds during production. The capability of using the spectral features to identify contaminants with other sensors which might only indicate a potential contamination level provides a real enhancement to current inspection systems such as Optical Stimulated Electron Emission (OSEE). The optical fiber probe can easily fit into the same scanning fixtures as the OSEE. The initial data obtained using the Guided Wave Model 260 spectrophotometer was primarily focused on determining spectra of potential contaminants such as HD2 grease, silicones, etc. However, once we began taking data and applying multivariate analysis techniques, using a program that can handle very large data sets, i.e., Unscrambler 2, it became apparent that the techniques also might provide a nice scientific tool for determining oxidation and chemisorption rates under controlled conditions. As the ultimate power of the technique became recognized, considering that the chemical system which was most frequently studied in this work is water + D6AC steel, we became very interested in trying the spectroscopic techniques to solve a broad range of problems. The complexity of the observed spectra for the D6AC + water system is due to overlaps between the water peaks, the resulting chemisorbed species, and products of reaction which also contain OH stretching bands. Unscrambling these spectral features, without knowledge of the specific species involved, has proven to be a formidable task.

  12. Surface currents on ideal plasmas

    SciTech Connect

    Webster, Anthony J.

    2010-11-15

    The surface (or 'skin') current that can flow at a perturbed interface between plasma and vacuum is considered in the approximation where a surface marks a sharp transition from plasma to vacuum. A short magnetohydrodynamic calculation gives an exact and general expression for the component perpendicular to the average of the magnetic field either side of the surface, finding it proportional to the edge plasma pressure. A consequence is that for all plasmas with zero surface current at equilibrium, the surface current associated with any linear instability will flow parallel to the magnetic field. The surface current is calculated for a simple but realistic model of a cylindrical plasma, and found to depend on the type of instability, and consequently on the particular plasma equilibrium. This is illustrated for two well known cases.

  13. Heterogeneous surfaces to repel proteins.

    PubMed

    Shen, Lei; Zhu, Jintao

    2016-02-01

    The nonspecific adsorption of proteins is usually undesirable on solid surfaces as it induces adverse responses, such as platelet adhesion on medical devices, negative signals of biosensors and contamination blockage of filtration membranes. Thus, an important scheme in material science is to design and fabricate protein-repulsive surfaces. Early approaches in this field focused on homogeneous surfaces comprised of single type functionality. Yet, recent researches have demonstrated that surfaces with heterogeneities (chemistry and topography) show promising performance against protein adsorption. In this review, we will summarize the recent achievements and discuss the new perspectives in the research of developing and characterizing heterogeneous surfaces to repel proteins. The protein repulsion mechanisms of different heterogeneous surfaces will also be discussed in details, followed by the perspective and challenge of this emerging field. PMID:26691416

  14. Friction surfaced Stellite6 coatings

    SciTech Connect

    Rao, K. Prasad; Damodaram, R.; Rafi, H. Khalid; Ram, G.D. Janaki; Reddy, G. Madhusudhan; Nagalakshmi, R.

    2012-08-15

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  15. Laser carbonitriding of alumina surface

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Akhtar, S. S.; Karatas, C.

    2011-03-01

    Laser carbonitriding of alumina surfaces is examined. Temperature and stress fields developed during the laser heating of the substrate surface are predicted using the finite element method in line with the experimental conditions. The formation of Al(C, N) and AlN compounds in the surface region of irradiated workpiece is examined using X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The microstructural and morphological changes in the laser irradiated region are examined using Scanning Electron Microscope (SEM). The microhardness of the resulting surface is measured and compared with the base material hardness. It is found that high temperature gradient is developed in the irradiated region, which in turn, results in high residual stress levels in this region. XPS and XRD data reveal the presence of Al (C, N) and AlN compounds in the surface region. The microhardness in the surface region of the laser treated workpiece increases significantly.

  16. Remote Sensing of Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.

    2001-01-01

    Our efforts have been focused on understanding the physical properties of planetary surfaces using remote sensing techniques. Specific application has been to the surfaces of the Moon and Mars. Our approach has been to use thermal-infrared emission and radar reflectance and scattering as a way of exploring the decimeter-scale structure of these surfaces. At this scale, the techniques are sensitive to physical parameters such as the average or effective particle size of surface materials, the degree of induration or physical bonding between individual regolith grains, and the abundance of rocks of different sizes resting on or admixed in to the surface. The results are relevant to understanding the geological processes that have affected the surface and, in the case of Mars, determining site safety and scientific relevance for planning upcoming lander, rover, and sample-return spacecraft missions. Specific results are discussed below, and publications that have resulted are listed at the end.

  17. Surface energies of elemental crystals.

    PubMed

    Tran, Richard; Xu, Zihan; Radhakrishnan, Balachandran; Winston, Donald; Sun, Wenhao; Persson, Kristin A; Ong, Shyue Ping

    2016-01-01

    The surface energy is a fundamental property of the different facets of a crystal that is crucial to the understanding of various phenomena like surface segregation, roughening, catalytic activity, and the crystal's equilibrium shape. Such surface phenomena are especially important at the nanoscale, where the large surface area to volume ratios lead to properties that are significantly different from the bulk. In this work, we present the largest database of calculated surface energies for elemental crystals to date. This database contains the surface energies of more than 100 polymorphs of about 70 elements, up to a maximum Miller index of two and three for non-cubic and cubic crystals, respectively. Well-known reconstruction schemes are also accounted for. The database is systematically improvable and has been rigorously validated against previous experimental and computational data where available. We will describe the methodology used in constructing the database, and how it can be accessed for further studies and design of materials. PMID:27622853

  18. Undergraduate Laboratory for Surface Science

    NASA Astrophysics Data System (ADS)

    Okumura, Mitchio; Beauchamp, Jesse L.; Dickert, Jeffrey M.; Essy, Blair R.; Claypool, Christopher L.

    1996-02-01

    Surface science has developed into a multidisciplinary field of research with applications ranging from heterogeneous catalysis to semiconductor etching (1). Aspects of surface chemistry are now included in physical chemistry textbooks (2) and undergraduate curricula (3), but the perceived cost and complexity of equipment has deterred the introduction of surface science methods in undergraduate laboratories (4). Efforts to expose chemistry undergraduates to state-of-the-art surface instrumentation have just begun (5). To provide our undergraduates with hands-on experience in using standard techniques for characterizing surface morphology, adsorbates, kinetics, and reaction mechanisms, we have developed a set of surface science experiments for our physical chemistry laboratory sequence. The centerpiece of the laboratory is an ultrahigh vacuum (UHV) chamber for studies of single crystal surfaces. This instrument, shown in the figure, has surface analysis capabilities including low energy electron diffraction (LEED), Auger spectroscopy, and temperature-programmed desorption (TPD). The laboratory exercises involve experiments on the well-studied Pt(111) surface. Students prepare a previously mounted single crystal sample by sputtering it with an argon ion gun and heating it under O2. Electron diffraction patterns from the cleaned surface are then obtained with a reverse view LEED apparatus (Princeton Instruments). Images are captured by a charge-coupled device (CCD) camera interfaced to a personal computer for easy downloading and subsequent analysis. Although the LEED images from a Pt(111) surface can be readily interpreted using simple diffraction arguments, this lab provides an excellent context for introducing Miller indices and reciprocal lattices (6). The surface chemical composition can be investigated by Auger spectroscopy, using the LEED apparatus as a simple energy analyzer. The temperature programmed desorption experiment, which is nearly complete, will be

  19. TOPICAL REVIEW: Surface enhanced fluorescence

    NASA Astrophysics Data System (ADS)

    Fort, Emmanuel; Grésillon, Samuel

    2008-01-01

    Fluorescence is widely used in optical devices, microscopy imaging, biology, medical research and diagnosis. Improving fluorescence sensitivity, all the way to the limit of single-molecular detection needed in many applications, remains a great challenge. The technique of surface enhanced fluorescence (SEF) is based upon the design of surfaces in the vicinity of the emitter. SEF yields an overall improvement in the fluorescence detection efficiency through modification and control of the local electromagnetic environment of the emitter. Near-field coupling between the emitter and surface modes plays a crucial role in SEF. In particular, plasmonic surfaces with localized and propagating surface plasmons are efficient SEF substrates. Recent progress in tailoring surfaces at the nanometre scale extends greatly the realm of SEF applications. This review focuses on the recent advances in the different mechanisms involved in SEF, in each case highlighting the most relevant applications.

  20. Drop Impact on Superheated Surfaces

    NASA Astrophysics Data System (ADS)

    Tran, Tuan; Staat, Hendrik J. J.; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

    2012-01-01

    At the impact of a liquid droplet on a smooth surface heated above the liquid’s boiling point, the droplet either immediately boils when it contacts the surface (“contact boiling”), or without any surface contact forms a Leidenfrost vapor layer towards the hot surface and bounces back (“gentle film boiling”), or both forms the Leidenfrost layer and ejects tiny droplets upward (“spraying film boiling”). We experimentally determine conditions under which impact behaviors in each regime can be realized. We show that the dimensionless maximum spreading γ of impacting droplets on the heated surfaces in both gentle and spraying film boiling regimes shows a universal scaling with the Weber number We (γ˜We2/5), which is much steeper than for the impact on nonheated (hydrophilic or hydrophobic) surfaces (γ˜We1/4). We also interferometrically measure the vapor thickness under the droplet.

  1. Experiencing and perceiving visual surfaces.

    PubMed

    Nakayama, K; Shimojo, S

    1992-09-01

    A theoretical framework is proposed to understand binocular visual surface perception based on the idea of a mobile observer sampling images from random vantage points in space. Application of the generic sampling principle indicates that the visual system acts as if it were viewing surface layouts from generic not accidental vantage points. Through the observer's experience of optical sampling, which can be characterized geometrically, the visual system makes associative connections between images and surfaces, passively internalizing the conditional probabilities of image sampling from surfaces. This in turn enables the visual system to determine which surface a given image most strongly indicates. Thus, visual surface perception can be considered as inverse ecological optics based on learning through ecological optics. As such, it is formally equivalent to a degenerate form of Bayesian inference where prior probabilities are neglected. PMID:1529336

  2. Superhydrophobicity for antifouling microfluidic surfaces.

    PubMed

    Shirtcliffe, N J; Roach, P

    2013-01-01

    Fouling of surfaces is often problematic in microfluidic devices, particularly when using protein or -enzymatic solutions. Various coating methods have been investigated to reduce the tendency for protein molecules to adsorb, mostly relying on hydrophobic surface chemistry or the antifouling ability of -polyethylene glycol. Here we present the potential use of superhydrophobic surfaces to not only reduce the amount of surface contamination but also to induce self-cleaning under flow conditions. The methodology is presented in order to prepare superhydrophobic surface coatings having micro- and nanoscale feature dimensions, as well as a step-by-step guide to quantify adsorbed protein down to nanogram levels. The fabrication of these surfaces as coatings via silica sol-gel and copper nano-hair growth is presented, which can be applied within microfluidic devices manufactured from various materials. PMID:23329449

  3. Surface roughness and infrared emission from the lunar surface

    NASA Astrophysics Data System (ADS)

    Vogler, Karl Joseph

    1994-01-01

    In order to understand thermal infrared spectra of the moon and solid-surfaced planetary bodies in terms of surface roughness and composition, a two-part project involving thermophysical computer models and infrared photometry has been pursued. The computer models calculate the infrared radiation emitted by an atmosphereless body with a macroscopically rough surface using radiative heat transfer methods. Multiple scattering of incident solar radiation, and multiple scattering and remission of thermal infrared radiation onto surrounding surface elements are included in the model. Surface roughness is modeled as paraboloidal holes characterized by a fractional coverage of a spherical object and a single depth-to-diameter ratio. Thermal emission from the rough surface is anisotropic and deviates from a gray body emission assumed by standard thermal models. The model explains to first-order published, mid infrared, measurements of the moon and Galilean Satellites. Surface composition is included by using results from Hapke for reflectance and emittance properties of a particulate surface. It is concluded that negative surface relief is required to explain the continuum behavior of the lunar thermal spectrum. An infrared photometer was constructed from an existing design and was configured in order to perform whole disk photometry of the moon at various phase angles. Measurements at 5.03, 8.4 and 11.5 micron were made at seven phase angles, ranging from -151 deg 55 min to 53 deg 27 min. The thermophysical computer models were modified so that disk-integrated emission as a function of phase angle could be calculated. Effects due to thermal inertia of the surface are not included in this simplified version of the model. The model calculations compare favorably with measurements of the moon made by the author, Sarri and Shorthill and Murdock. It is concluded that surface roughness is necessary in explaining the shape of the lunar thermal emission with phase angle.

  4. Assimilation of Surface Temperature in Land Surface Models

    NASA Technical Reports Server (NTRS)

    Lakshmi, Venkataraman

    1998-01-01

    Hydrological models have been calibrated and validated using catchment streamflows. However, using a point measurement does not guarantee correct spatial distribution of model computed heat fluxes, soil moisture and surface temperatures. With the advent of satellites in the late 70s, surface temperature is being measured two to four times a day from various satellite sensors and different platforms. The purpose of this paper is to demonstrate use of satellite surface temperature in (a) validation of model computed surface temperatures and (b) assimilation of satellite surface temperatures into a hydrological model in order to improve the prediction accuracy of soil moistures and heat fluxes. The assimilation is carried out by comparing the satellite and the model produced surface temperatures and setting the "true"temperature midway between the two values. Based on this "true" surface temperature, the physical relationships of water and energy balance are used to reset the other variables. This is a case of nudging the water and energy balance variables so that they are consistent with each other and the true" surface temperature. The potential of this assimilation scheme is demonstrated in the form of various experiments that highlight the various aspects. This study is carried over the Red-Arkansas basin in the southern United States (a 5 deg X 10 deg area) over a time period of a year (August 1987 - July 1988). The land surface hydrological model is run on an hourly time step. The results show that satellite surface temperature assimilation improves the accuracy of the computed surface soil moisture remarkably.

  5. Wettability of natural superhydrophobic surfaces.

    PubMed

    Webb, Hayden K; Crawford, Russell J; Ivanova, Elena P

    2014-08-01

    Since the description of the 'Lotus Effect' by Barthlott and Neinhuis in 1997, the existence of superhydrophobic surfaces in the natural world has become common knowledge. Superhydrophobicity is associated with a number of possible evolutionary benefits that may be bestowed upon an organism, ranging from the ease of dewetting of their surfaces and therefore prevention of encumbrance by water droplets, self-cleaning and removal of particulates and potential pathogens, and even to antimicrobial activity. The superhydrophobic properties of natural surfaces have been attributed to the presence of hierarchical microscale (>1 μm) and nanoscale (typically below 200 nm) structures on the surface, and as a result, the generation of topographical hierarchy is usually considered of high importance in the fabrication of synthetic superhydrophobic surfaces. When one surveys the breadth of data available on naturally existing superhydrophobic surfaces, however, it can be observed that topographical hierarchy is not present on all naturally superhydrophobic surfaces; in fact, the only universal feature of these surfaces is the presence of a sophisticated nanoscale structure. Additionally, several natural surfaces, e.g. those present on rose petals and gecko feet, display high water contact angles and high adhesion of droplets, due to the pinning effect. These surfaces are not truly superhydrophobic, and lack significant degrees of nanoscale roughness. Here, we discuss the phenomena of superhydrophobicity and pseudo-superhydrophobicity in nature, and present an argument that while hierarchical surface roughness may aid in the stability of the superhydrophobic effect, it is nanoscale surface architecture alone that is the true determinant of superhydrophobicity. PMID:24556235

  6. Titan's rotation - Surface feature observed

    NASA Astrophysics Data System (ADS)

    Lemmon, M. T.; Karkoschka, E.; Tomasko, M.

    1993-06-01

    A surface feature or a near-surface fracture is suggested to account for the time variations in the 0.94, 1.08, and 1.28 micron atmospheric windows of Titan's geometric albedo, relative to its albedo in adjacent methane bands. These observations are noted to be consistent with synchronous rotation. They can also be explained by a 0.1-higher surface albedo on Titan's leading hemisphere.

  7. Surface characterization and contamination analysis

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1994-01-01

    The research activity for this first year has focussed on three distinct activities: (1) the use of an integrating sphere to improve upon the gathering of spectral data from a variety of surfaces; (2) the use of optical fiber spectrometry to determine levels of contamination from tape residues on critical bonding surfaces; and (3) an exploratory activity in the use of spectroscopic ellipsometry for the analysis of thin films of contaminants on critical surfaces has also begun.

  8. Slope sensitivities for optical surfaces

    NASA Astrophysics Data System (ADS)

    Rogers, John R.

    2015-09-01

    Setting a tolerance for the slope errors of an optical surface (e.g., surface form errors of the "mid-spatial-frequencies") requires some knowledge of how those surface errors affect the final image of the system. While excellent tools exist for simulating those effects on a surface-by-surface basis, considerable insight may be gained by examining, for each surface, a simple sensitivity parameter that relates the slope error on the surface to the ray displacement at the final image plane. Snell's law gives a relationship between the slope errors of a surface and the angular deviations of the rays emerging from the surface. For a singlet or thin doublet acting by itself, these angular deviations are related to ray deviations at the image plane by the focal length of the lens. However, for optical surfaces inside an optical system having a substantial axial extent, the focal length of the system is not the correct multiplier, as the sensitivity is influenced by the optical surfaces that follow. In this paper, a simple expression is derived that relates the slope errors at an arbitrary optical surface to the ray deviation at the image plane. This expression is experimentally verified by comparison to a real-ray perturbation analysis. The sensitivity parameter relates the RMS slope errors to the RMS spot radius, and also relates the peak slope error to the 100% spot radius, and may be used to create an RSS error budget for slope error. Application to various types of system are shown and discussed.

  9. Nonlinear optical studies of surfaces

    NASA Astrophysics Data System (ADS)

    Shen, Y. R.

    1994-07-01

    The possibility of using nonlinear optical processes for surface studies has attracted increasing attention in recent years. Optical second harmonic generation (SHG) and sum frequency generation (SFG), in particular, have been well accepted as viable surface probes. They have many advantages over the conventional techniques. By nature, they are highly surface-specific and has a submonolayer sensitivity. As coherent optical processes, they are capable of in-situ probing of surfaces in hostile environment as well as applicable to all interfaces accessible by light. With ultrafast pump laser pulses, they can be employed to study surface dynamic processes with a subpicosecond time resolution. These advantages have opened the door to many exciting research opportunities in surface science and technology. This paper gives a brief overview of this fast-growing new area of research. Optical SHG from a surface was first studied theoretically and experimentally in the sixties. Even the submonolayer surface sensitivity of the process was noticed fairly early. The success was, however, limited because of difficulties in controlling the experimental conditions. It was not until the early 1980's that the potential of the process for surface analysis was duly recognized. The first surface study by SHG was actually motivated by the then active search for an understanding of the intriguing surface enhanced Raman scattering (SERS). It had been suspected that the enhancement in SERS mainly came from the local-field enhancement due to local plasmon resonances and pointing rod effect on rough metal surfaces. In our view, Raman scattering is a two-photon process and is therefore a nonlinear optical effect.

  10. BOREAS Derived Surface Meteorological Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Twine, Tracy; Rinker, Donald; Knapp, David

    2000-01-01

    In 1995, the BOREAS science teams identified the need for a continuous surface meteorological and radiation data set to support flux and surface process modeling efforts. This data set contains actual, substituted, and interpolated 15-minute meteorological and radiation data compiled from several surface measurements sites over the BOREAS SSA and NSA. Temporally, the data cover 01-Jan-1994 to 31-Dec-1996. The data are stored in tabular ASCII files, and are classified as AFM-Staff data.

  11. Nonlinear optical studies of surfaces

    SciTech Connect

    Shen, Y.R.

    1994-07-01

    The possibly of using nonlinear optical processes for surface studies has attracted increasing attention in recent years. Optical second harmonic generation (SHG) and sum frequency generation (SFG), in particular, have been well accepted as viable surface probes. They have many advantages over the conventional techniques. By nature, they are highly surface-specific and has a submonolayer sensitivity. As coherent optical processes, they are capable of in-situ probing of surfaces in hostile environment as well as applicable to all interfaces accessible by light. With ultrafast pump laser pulses, they can be employed to study surface dynamic processes with a subpicosecond time resolution. These advantages have opened the door to many exciting research opportunities in surface science and technology. This paper gives a brief overview of this fast-growing new area of research. Optical SHG from a surface was first studied theoretically and experimentally in the sixties. Even the submonolayer surface sensitivity of the process was noticed fairly early. The success was, however, limited because of difficulties in controlling the experimental conditions. It was not until the early 1980`s that the potential of the process for surface analysis was duly recognized. The first surface study by SHG was actually motivated by the then active search for an understanding of the intriguing surface enhanced Raman scattering (SERS). It had been suspected that the enhancement in SERS mainly came from the local-field enhancement due to local plasmon resonances and pointing rod effect on rough metal surfaces. In our view, Raman scattering is a two-photon process and is therefore a nonlinear optical effect.

  12. DNA Electrophoresis on Nanopatterned surfaces

    NASA Astrophysics Data System (ADS)

    Luo, Haobin; Gersappe, Dilip

    2002-03-01

    Conventional electrophoretic methods for DNA separation use topological restriction such as the network point in a gel to separate DNA. Here, we present a new approach to DNA electrophoresis using a nanopatterned surface. We exploit the conformational differences that arise when chains of different length are adsorbed onto a flat nanopatterned surface. We use a MD simulation to determine conditions that will optimize separation and present guidelines for the design of nanopatterned surfaces that can separate DNA in a broad size range.

  13. Displacement current and surface flashover

    NASA Astrophysics Data System (ADS)

    Harris, J. R.; Caporaso, G. J.; Blackfield, D.; Chen, Y.-J.

    2007-09-01

    High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, it is shown that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

  14. Templating Surfaces with Gradient Assemblies

    SciTech Connect

    Genzer,J.

    2005-01-01

    One of the most versatile and widely used methods of forming surfaces with position-dependent wettability is that conceived by Chaudhury and Whitesides more than a decade ago. In this paper we review several projects that utilize this gradient-forming methodology for: controlled of deposition of self-assembled monolayers on surfaces, generating arrays of nanoparticles with number density gradients, probing the mushroom-to-brush transition in surface-anchored polymers, and controlling the speed of moving liquid droplets on surfaces.

  15. Chemical modification of surface properties

    SciTech Connect

    Koel, B.E.; Windham, R.G.

    1987-01-01

    Chemically tailoring materials to have new and unique surface properties has enormous potential in a wide variety of applications for interfacial phenomena in materials science and catalysis. Recent work from our laboratory on model systems designed to explain how changes in geometric and electronic structure of metal surfaces affect surface chemistry are discussed. Specifically, the influence of potassium and bismuth coadsorption with small molecules on a Pt(111) single crystal surface will be described. We will also discuss the chemical reactivity of palladium metal monolayers and thin films which have been recently reported to have dramatically altered geometric and electronic structure. 31 refs., 3 figs.

  16. Groove growth by surface subdiffusion

    NASA Astrophysics Data System (ADS)

    Abu Hamed, M.; Nepomnyashchy, A. A.

    2015-04-01

    The investigation of the grain-boundary groove growth by normal surface diffusion was first done by Mullins. However, the diffusion on a solid surface is often anomalous. Recently, the groove growth in the case of surface superdiffusion has been analyzed. In the present paper, the problem of the groove growth is solved in the case of the surface subdiffusion. An exact self-similar solution is obtained and represented in terms of the Fox H-function. Basic properties of the solution are described.

  17. Antenna surface contour control system

    NASA Technical Reports Server (NTRS)

    Ahl, Elvin L. (Inventor); Miller, James B. (Inventor)

    1989-01-01

    The invention is a system for automatically controlling the surface contour of a deployable and restowable antenna having a mesh reflector surface supported by a circular, folding hoop affixed to a central, telescoping column. The antenna, when deployed, forms a quad-aperture reflector with each quadrant of the mesh surface shaped to provide an offset parabolic radio frequency (RF) reflector. The hoop is supported and positioned by quartz support cords attached to the top of a column and by lower graphite hoop control cords that extend between the hoop and base of the column. The antenna, an RF reflective surface, is a gold plated molybdenum wire mesh supported on a graphite cord truss structure that includes the hoop control cords and a plurality of surface control cords attached at selected points on the surface and to the base of the column. The contour of the three-dimensional surface of the antenna is controlled by selectively adjusting the lengths of the surface control cords and the graphite hoop control cords by means of novel actuator assemblies that automatically sense and change the lengths of the lower hoop control cords and surface control cords.

  18. Preparation of hydroxylated polyethylene surfaces.

    PubMed

    Zand, A; Walter, N; Bahu, M; Ketterer, S; Sanders, M; Sikorski, Y; Cunningham, R; Beholz, L

    2008-01-01

    The surfaces of high-density or ultra-high-molecular-weight polyethylenes were hydroxylated using a two-step process. The wetting and wear properties of the untreated (virgin) and surface hydroxylated polyethylenes were compared. The introduction of hydroxyl groups provided an increase in surface hydrophilicity resulting in reduced wear. Hydrophilicity was analyzed by optical analysis of water contact angle. Wear was determined by weight loss under conditions of a reciprocating pin-on-plate apparatus with the panels immersed in water or calf serum. These results suggest that hydroxylation of polyethylene friction-bearing orthopedic surfaces may lead to a longer joint life. PMID:18318959

  19. Thermocapillary flow on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Baier, Tobias; Steffes, Clarissa; Hardt, Steffen

    2010-09-01

    A liquid in Cassie-Baxter state above a structured superhydrophobic surface is ideally suited for surface driven transport due to its large free surface fraction in close contact to a solid. We investigate thermal Marangoni flow over a superhydrophobic array of fins oriented parallel or perpendicular to an applied temperature gradient. In the Stokes limit we derive an analytical expression for the bulk flow velocity above the surface and compare it with numerical solutions of the Navier-Stokes equation. Even for moderate temperature gradients comparatively large flow velocities are induced, suggesting to utilize this principle for microfluidic pumping.

  20. Roughness reduction on aspheric surfaces

    NASA Astrophysics Data System (ADS)

    Kiontke, S.; Kokot, Sebastian

    2015-02-01

    For a lot of applications like spectrometer and high power laser roughness as an important parameter has been discussed over and over again. Especially for high power systems the surface quality is crucial for determining the damage threshold and therefore the field of application. Above that, it has often been difficult to compare roughness measurements because of different measurement methods and the usage of filters and surface fits. Measurement results differ significantly depending on filters and especially on the measured surface size. Insights will be given how values behave depending on the quality of surface and the size of measured area. Many applications require a high quality of roughness in order to reduce scattering. Some of them in order to prevent from damage like high power laser applications. Others like spectrometers seek to increase the signal-to-noise ratio. Most of them have already been built with spherical surfaces. With higher demands on efficiency and more sophisticated versions aspherical surfaces need to be employed. Therefore, the high requirement in roughness known from spherical surfaces is also needed on aspherical surfaces. For one thing, the constant change of curvature of an aspherical surface accounts for the superior performance, for another thing, it prevents from using classical polishing technics, which guarantied this low roughness. New methods need to be qualified. In addition, also results of a new manufacturing process will be shown allowing low roughness on aspheric even with remarkable departure from the best fit sphere.

  1. Surface and Step Conductivities on Si(111) Surfaces.

    PubMed

    Just, Sven; Blab, Marcus; Korte, Stefan; Cherepanov, Vasily; Soltner, Helmut; Voigtländer, Bert

    2015-08-01

    Four-point measurements using a multitip scanning tunneling microscope are carried out in order to determine surface and step conductivities on Si(111) surfaces. In a first step, distance-dependent four-point measurements in the linear configuration are used in combination with an analytical three-layer model for charge transport to disentangle the 2D surface conductivity from nonsurface contributions. A termination of the Si(111) surface with either Bi or H results in the two limiting cases of a pure 2D or 3D conductance, respectively. In order to further disentangle the surface conductivity of the step-free surface from the contribution due to atomic steps, a square four-probe configuration is applied as a function of the rotation angle. In total, this combined approach leads to an atomic step conductivity of σ(step)=(29±9)  Ω(-1) m(-1) and to a step-free surface conductivity of σ(surf)=(9±2)×10(-6)  Ω(-1)/□ for the Si(111)-(7×7) surface. PMID:26296126

  2. Improved surface volume estimates for surface irrigation balance calculations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volume balance calculations used in surface irrigation engineering analysis require estimates of surface storage. Typically, these calculations use the Manning formula and normal depth assumption to calculate upstream flow depth (and thus flow area), and a constant shape factor to describe the rela...

  3. Astronaut Alan Bean deploys Lunar Surface Magnetometer on lunar surface

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Astronaut Alan L. Bean, lunar module pilot, deploys the Lunar Surface Magnetometer (LSM) during the first Apollo 12 extravehicular activity on the Moon. The LSM is a component of the Apollo Lunar Surface Experiments Package (ALSEP). The Lunar Module can be seen in the left background.

  4. Surface roughness of flat and curved optical surfaces

    NASA Technical Reports Server (NTRS)

    George, M. C.; Reddy, Bandi Jagannadha; Jagannath, H.; Perera, M.; Venkateswarlu, P.

    1989-01-01

    Surface roughness measurement has several applications. Even a few A roughness will cause scattered light in optical systems. Smooth surfaces are required in a wide variety of instruments. For example, the outputs of the high power lasers are limited by the surface roughness of mirrors and windows. Similarly, the information storage capacity of magnetic media is limited by the roughness of the surface. Roughness reduces the resolving power of optics and distorts images. The performance of certain thin film components in electronic industries is affected by the roughness on the film surface. X-ray astronomical telescopes require smooth curved surfaces. To improve the surface quality, super sensitive detection methods are required. Wide ranging measurement techniques are developed based on interferometry, electron microscopy, C-rays, ellipsometry, light scattering, and using mechanical stylus, etc. Though there are several techniques available for measurement and evaluation of the surfaces, no single technique is fully adequate. Also, the technique used should be nondestructive and highly sensitive. So, an optical heterodyne profilometer was fabricated. Its current sensitivity is much better than 10A rms. It is a noncontact and nondestructive technique. The instrument can be operated even by unskilled personnel for routine measurements.

  5. Near surface flow structure over a dimpled surface with blowing

    NASA Astrophysics Data System (ADS)

    Borchetta, Colby; Martin, Alexandre; Bailey, Sean

    2015-11-01

    The combined effects of surface roughness with flow injection are of particular interest in understanding the flow over ablative heat-shields, a common form of thermal protection system (TPS) used for atmospheric entry. Stereoscopic, time-resolved particle image velocimetry was used to investigate the near-surface flow over a surface geometry consisting of hexagonal dimples, typical of a TPS. Of particular interest are the modifications made to the flow structures generated by the dimpled elements caused by flow injection through the surface. Without flow injection, inclined flow structures are generated periodically at the upstream edge of the dimples and convected downstream. This behavior is coupled with fluid becoming entrained inside the dimples, recirculating and ejecting away from the surface. When flow injection occurs through the surface, this process occupies a larger region of the flow, extending further from the surface, with a corresponding increase in the size of the convecting structures and increase in turbulent kinetic energy. These features persist over the range of Reynolds numbers investigated, with increasing Reynolds number resulting in increased turbulence and a corresponding broadening of the region of the flow influenced by the surface. This research is supported by NASA Award NNX13AN04A.

  6. Interactive Display of Surfaces Using Subdivision Surfaces and Wavelets

    SciTech Connect

    Duchaineau, M A; Bertram, M; Porumbescu, S; Hamann, B; Joy, K I

    2001-10-03

    Complex surfaces and solids are produced by large-scale modeling and simulation activities in a variety of disciplines. Productive interaction with these simulations requires that these surfaces or solids be viewable at interactive rates--yet many of these surfaced solids can contain hundreds of millions of polygondpolyhedra. Interactive display of these objects requires compression techniques to minimize storage, and fast view-dependent triangulation techniques to drive the graphics hardware. In this paper, we review recent advances in subdivision-surface wavelet compression and optimization that can be used to provide a framework for both compression and triangulation. These techniques can be used to produce suitable approximations of complex surfaces of arbitrary topology, and can be used to determine suitable triangulations for display. The techniques can be used in a variety of applications in computer graphics, computer animation and visualization.

  7. Fermi surfaces of surface states on Si(111)-Ag, Au

    NASA Astrophysics Data System (ADS)

    Crain, J. N.; Altmann, K. N.; Bromberger, C.; Himpsel, F. J.

    2002-11-01

    Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on Si(111)(3)×(3)-Ag, Si(111)(3)×(3)-Au, and Si(111)(21)×(21)-(Ag+Au). For Si(111)(3)×(3)-Ag the Fermi surface consists of small electron pockets populated by electrons from a few % excess Ag. For Si(111)(21)×(21)-(Ag+Au) the pockets increase their size corresponding to a filling by three electrons per unit cell. The (21)×(21) superlattice leads to an intricate surface umklapp pattern and to minigaps of 110 meV, giving an interaction potential of 55 meV for the (21)×(21) superlattice.

  8. Surface morphology of GaN: Flat versus vicinal surfaces

    SciTech Connect

    Xie, M.H.; Seutter, S.M.; Zheng, L.X.; Cheung, S.H.; Ng, Y.F.; Wu, H.; Tong, S.Y.

    2000-07-01

    The surface morphology of GaN films grown by molecular beam epitaxy (MBE) is investigated by scanning tunneling microscopy (STM). A comparison is made between flat and vicinal surfaces. The wurtzite structure of GaN leads to special morphological features such as step pairing and triangularly shaped islands. Spiral mounds due to growth at screw threading dislocations are dominant on flat surfaces, whereas for vicinal GaN, the surfaces show no spiral mound but evenly spaced steps. This observation suggests an effective suppression of screw threading dislocations in the vicinal films. This finding is confirmed by transmission electron microscopy (TEM) studies. Continued growth of the vicinal surface leads to step bunching that is attributed to the effect of electromigration.

  9. Solvation forces between rough surfaces

    SciTech Connect

    Frink, L.J.; van Swol, F.

    1998-04-01

    We investigate the role of surface roughness on solvation forces and solvation free energies. Roughness is introduced by dividing a surface into an array of square tiles that are then randomly displaced in the direction perpendicular to the wall. The integrated wall strength of these tiled surfaces is independent of the surface roughness and hence this class of rough walls is ideally suited for isolating roughness effects. We use grand canonical Monte Carlo simulations of a Lennard-Jones fluid confined in a slit pore with rough walls to generate the solvation interactions as a function of roughness, tile size, and surface area. The simulation data are compared to a simple superposition approximation of smooth wall solvation interactions (obtained from simulation or density functional theory), based on a distribution of wall separations. We find that this approximation provides a surprisingly accurate route to the solvation interaction of rough surfaces. In general, increased roughness leads to a reduction of oscillations in the solvation forces and surface free energies. However, nonmonotonic behavior of the oscillation amplitude with roughness can be observed for finite surfaces. The washing out of the oscillations found for large surface roughness produces a solvation force that exhibits a broad repulsive peak with separation. The broad repulsion is a consequence of the resistance to squeezing out fluid from the smallest gaps between two opposing rough surfaces. It is as much a reflection of packing effects as are the solvation oscillations for perfectly smooth pores. In addition, we present results for patterned and undulating surfaces produced by an analogous modification of the one-body external field for smooth walls. Finally, we discuss the implications of our results for a number of experimental systems including self-assembled monolayers, microporous materials, protein solutions, and DNA crystals. {copyright} {ital 1998 American Institute of Physics.}

  10. Correlating simulated surface marks with near-surface tornado structure

    NASA Astrophysics Data System (ADS)

    Zimmerman, Michael I.

    Tornadoes often leave behind patterns of debris deposition, or "surface marks", which provide a direct signature of their near surface winds. The intent of this thesis is to investigate what can be learned about near-surface tornado structure and intensity through the properties of surface marks generated by simulated, debris-laden tornadoes. Earlier work showed through numerical simulations that the tornado's structure and intensity is highly sensitive to properties of the near-surface flow and can change rapidly in time for some conditions. The strongest winds often occur within tens of meters of the surface where the threat to human life and property is highest, and factors such as massive debris loadings and asymmetry of the main vortex have proven to be critical complications in some regimes. However, studying this portion of the flow in the field is problematic; while Doppler radar provides the best tornado wind field measurements, it cannot probe below about 20 m, and interpretation of Doppler data requires assumptions about tornado symmetry, steadiness in time, and correlation between scatterer and air velocities that are more uncertain near the surface. As early as 1967, Fujita proposed estimating tornado wind speeds from analysis of aerial photography and ground documentation of surface marks. A handful of studies followed but were limited by difficulties in interpreting physical origins of the marks, and little scientific attention has been paid to them since. Here, Fujita's original idea is revisited in the context of three-dimensional, large-eddy simulations of tornadoes with fully-coupled debris. In this thesis, the origins of the most prominent simulated marks are determined and compared with historical interpretations of real marks. The earlier hypothesis that cycloidal surface marks were directly correlated with the paths of individual vortices (either the main vortex or its secondary vortices, when present) is unsupported by the simulation results

  11. CONNECTICUT SURFACE WATER QUALITY CLASSIFICATIONS

    EPA Science Inventory

    This is a 1:24,000-scale datalayer of Surface Water Quality Classifications for Connecticut. It is comprised of two 0Shapefiles with line and polygon features. Both Shapefiles must be used together with the Hydrography datalayer. The polygon Shapefile includes surface water qual...

  12. Surface finishing. [for aircraft wings

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    A surface of an article adapted for relative motion with a fluid environment is finished by coating the surface with a fluid adhesive. The adhesive is covered with a sheet of flexible film material under tension, and the adhesive is set while maintaining tension on the film material.

  13. Surface Modification of Zein Films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel method to derivatize the surface of zein is devised that can modify the water absorption and surface wetting behavior. The reagents used to impart the desired properties in a reasonable amount of time include octenyl succinic anhydride and alkyl and alkenyl ketene dimers. The method is eas...

  14. Ceramic coatings on smooth surfaces

    NASA Technical Reports Server (NTRS)

    Miller, R. A. (Inventor); Brindley, W. J. (Inventor); Rouge, C. J. (Inventor)

    1991-01-01

    A metallic coating is plasma sprayed onto a smooth surface of a metal alloy substitute or on a bond coating. An initial thin ceramic layer is low pressure sprayed onto the smooth surface of the substrate or bond coating. Another ceramic layer is atmospheric plasma sprayed onto the initial ceramic layer.

  15. Surface Organization Influences Bistable Vision

    ERIC Educational Resources Information Center

    Graf, Erich W.; Adams, Wendy J.

    2008-01-01

    A priority for the visual system is to construct 3-dimensional surfaces from visual primitives. Information is combined across individual cues to form a robust representation of the external world. Here, it is shown that surface completion relying on multiple visual cues influences relative dominance during binocular rivalry. The shape of a…

  16. Lightness Constancy in Surface Visualization.

    PubMed

    Szafir, Danielle Albers; Sarikaya, Alper; Gleicher, Michael

    2016-09-01

    Color is a common channel for displaying data in surface visualization, but is affected by the shadows and shading used to convey surface depth and shape. Understanding encoded data in the context of surface structure is critical for effective analysis in a variety of domains, such as in molecular biology. In the physical world, lightness constancy allows people to accurately perceive shadowed colors; however, its effectiveness in complex synthetic environments such as surface visualizations is not well understood. We report a series of crowdsourced and laboratory studies that confirm the existence of lightness constancy effects for molecular surface visualizations using ambient occlusion. We provide empirical evidence of how common visualization design decisions can impact viewers' abilities to accurately identify encoded surface colors. These findings suggest that lightness constancy aids in understanding color encodings in surface visualization and reveal a correlation between visualization techniques that improve color interpretation in shadow and those that enhance perceptions of surface depth. These results collectively suggest that understanding constancy in practice can inform effective visualization design. PMID:26584495

  17. Optical behavior of surface bubbles

    NASA Astrophysics Data System (ADS)

    Straulino, Samuele; Gambi, Cecilia M. C.; Molesini, Giuseppe

    2015-11-01

    The observation of diamond-like light spots produced by surface bubbles obliquely illuminated is reported. The phenomenon is discussed in terms of geometrical optics, and an explanation is provided attributing the effect to the astigmatism introduced by the deformation of the liquid surface surrounding the bubble. An essential ray tracing program is outlined and used to reconstruct the observed phenomenon numerically.

  18. COLLECTION OF UNDISTURBED SURFACE SEDIMENTS

    EPA Science Inventory

    The National Resource Council identified the need for a capability to collect undisturbed surface sediments. Surface sediments are an important source for most exposure of fish to polychlorinated biphenyls via direct uptake from water in contact with sediments. An innovative sedi...

  19. Localized spoof surface plasmons in textured open metal surfaces.

    PubMed

    Gao, Zhen; Gao, Fei; Xu, Hongyi; Zhang, Youming; Zhang, Baile

    2016-05-15

    We experimentally demonstrate that textured open metal surfaces, i.e., the ultrathin fan-shaped metallic strips, are able to support spoof localized surface plasmons (spoof-LSPs) in the microwave frequencies. Unlike conventional spoof-LSPs supported on textured closed metal surfaces, which originate from the interference of clockwise and counterclockwise propagating surface modes, spoof-LSPs on textured open metal surfaces arise from the Fabry-Perot-like resonances due to the terminations of the open surfaces. We show that both the number of modes and the resonance frequencies of spoof-LSPs on textured open metal surfaces can be engineered through tuning the grating numbers (or total length) of the structured fan-shaped metallic strip. This enables the tuning of the spoof-plasmonic resonator by simply changing its length, rather than the complete geometry, simplifying the design to just one degree of freedom. Experimental evidence of the spoof-LSP Fabry-Perot resonators in the microwave regimes is presented with near-field response spectra and mode profiles imaged directly. PMID:27176957

  20. Scanning Surface Potential Microscopy of Spore Adhesion on Surfaces

    SciTech Connect

    Lee, Ida; Chung, Eunhyea; Kweon, Hyojin; Yiacoumi, Sotira; Tsouris, Costas

    2012-01-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.

  1. Background canceling surface alpha detector

    DOEpatents

    MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

    1996-01-01

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

  2. Background canceling surface alpha detector

    DOEpatents

    MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

    1996-06-11

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

  3. Surface acquisition through virtual milling

    NASA Technical Reports Server (NTRS)

    Merriam, Marshal L.

    1993-01-01

    Surface acquisition deals with the reconstruction of three dimensional objects from a set of data points. The most straightforward techniques require human intervention, a time consuming proposition. It is desirable to develop a fully automated alternative. Such a method is proposed in this paper. It makes use of surface measurements obtained from a 3-D laser digitizer - an instrument which provides the (x,y,z) coordinates of surface data points from various viewpoints. These points are assembled into several partial surfaces using a visibility constraint and a 2-D triangulation technique. Reconstruction of the final object requires merging these partial surfaces. This is accomplished through a procedure that emulates milling, a standard machining operation. From a geometrical standpoint the problem reduces to constructing the intersection of two or more non-convex polyhedra.

  4. Surface reactions of natural glasses

    SciTech Connect

    White, A.F.

    1986-12-31

    Reactions at natural glass surfaces are important in studies involving nuclear waste transport due to chemical control on ground water in host rocks such as basalt and tuff, to potential diffusion into natural hydrated glass surfaces and as natural analogs for waste glass stability. Dissolution kinetics can be described by linear surface reaction coupled with cation interdiffusion with resulting rates similar to those of synthetic silicate glasses. Rates of Cs diffusion into hydrated obsidian surfaces between 25{sup 0} and 75{sup 0}C were determined by XPS depth profiles and loss rates from aqueous solutions. Calculated diffusion coefficients were ten others of magnitude more rapid than predicted from an Arrhenius extrapolation of high temperature tracer diffusion data due to surface hydration reactions.

  5. Surface structure determines dynamic wetting

    PubMed Central

    Wang, Jiayu; Do-Quang, Minh; Cannon, James J.; Yue, Feng; Suzuki, Yuji; Amberg, Gustav; Shiomi, Junichiro

    2015-01-01

    Liquid wetting of a surface is omnipresent in nature and the advance of micro-fabrication and assembly techniques in recent years offers increasing ability to control this phenomenon. Here, we identify how surface roughness influences the initial dynamic spreading of a partially wetting droplet by studying the spreading on a solid substrate patterned with microstructures just a few micrometers in size. We reveal that the roughness influence can be quantified in terms of a line friction coefficient for the energy dissipation rate at the contact line, and that this can be described in a simple formula in terms of the geometrical parameters of the roughness and the line-friction coefficient of the planar surface. We further identify a criterion to predict if the spreading will be controlled by this surface roughness or by liquid inertia. Our results point to the possibility of selectively controlling the wetting behavior by engineering the surface structure. PMID:25683872

  6. Surface electrostatics: theory and computations

    PubMed Central

    Chatzigeorgiou, G.; Javili, A.; Steinmann, P.

    2014-01-01

    The objective of this work is to study the electrostatic response of materials accounting for boundary surfaces with their own (electrostatic) constitutive behaviour. The electric response of materials with (electrostatic) energetic boundary surfaces (surfaces that possess material properties and constitutive structures different from those of the bulk) is formulated in a consistent manner using a variational framework. The forces and moments that appear due to bulk and surface electric fields are also expressed in a consistent manner. The theory is accompanied by numerical examples on porous materials using the finite-element method, where the influence of the surface electric permittivity on the electric displacement, the polarization stress and the Maxwell stress is examined. PMID:24711720

  7. Upscaling and Downscaling of Land Surface Fluxes with Surface Temperature

    NASA Astrophysics Data System (ADS)

    Kustas, W. P.; Anderson, M. C.; Hain, C.; Albertson, J. D.; Gao, F.; Yang, Y.

    2015-12-01

    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 in the surface and root zone. Data from airborne and satellite-based platforms provide LST from ~10 km to sub meter resolutions. A land surface scheme called the Two-Source Energy Balance (TSEB) model has been incorporated into a multi-scale regional modeling system ALEXI (Atmosphere Land Exchange Inverse) and a disaggregation scheme (DisALEXI) using higher resolution LST. Results with this modeling system indicates that it can be applied over heterogeneous land surfaces and estimate reliable surface fluxes with minimal in situ information. Consequently, this modeling system allows for scaling energy fluxes from subfield to regional scales in regions with little ground data. In addition, the TSEB scheme has been incorporated into a large Eddy Simulation (LES) model for investigating dynamic interactions between variations in the land surface state reflected in the spatial pattern in LST and the lower atmospheric air properties affecting energy exchange. An overview of research results on scaling of fluxes and interactions with the lower atmosphere from the subfield level to regional scales using the TSEB, ALEX/DisALEX and the LES-TSEB approaches will be presented. Some unresolved issues in the use of LST at different spatial resolutions for estimating surface energy balance and upscaling fluxes, particularly evapotranspiration, will be discussed.

  8. Detecting contamination on a metal surface

    NASA Technical Reports Server (NTRS)

    Harris, J. M.; Marcus, H. L.; Smith, T.

    1977-01-01

    Thin layers of contaminant on metal surface are detected by measuring surface-potential difference between reference electrode and surface of interest. Procedure does not require mechanical contact with surface under examination.

  9. Modification of Surface Energy via Direct Laser Ablative Surface Patterning

    NASA Technical Reports Server (NTRS)

    Wohl, Christopher J., Jr. (Inventor); Belcher, Marcus A. (Inventor); Connell, John W. (Inventor); Hopkins, John W. (Inventor)

    2015-01-01

    Surface energy of a substrate is changed without the need for any template, mask, or additional coating medium applied to the substrate. At least one beam of energy directly ablates a substrate surface to form a predefined topographical pattern at the surface. Each beam of energy has a width of approximately 25 micrometers and an energy of approximately 1-500 microJoules. Features in the topographical pattern have a width of approximately 1-500 micrometers and a height of approximately 1.4-100 micrometers.

  10. Surface Ionization Gas Detection at SnO2 Surfaces

    NASA Astrophysics Data System (ADS)

    Krenkow, A.; Oberhüttinger, C.; Habauzit, A.; Kessler, M.; Göbel, J.; Müller, G.

    2009-05-01

    In surface ionization (SI) gas detection adsorbed analyte molecules are converted into ionic species at a heated solid surface and extracted into free space by an oppositely biased counter electrode. In the present work we consider the formation of positive and negative analyte gas ions at SnO2 surfaces. We find that SI leads to positive ion formation only, with the SI efficiency scaling with the ionization energy of the analyte gas molecules. Aromatic and aliphatic hydrocarbons with amine functional groups exhibit particularly high SI efficiencies.

  11. Computing Incompressible Flows With Free Surfaces

    NASA Technical Reports Server (NTRS)

    Kothe, D.

    1994-01-01

    RIPPLE computer program models transient, two-dimensional flows of incompressible fluids with surface tension on free surfaces of general shape. Surface tension modeled as volume force derived from continuum-surface-force model, giving RIPPLE both robustness and accuracy in modeling surface-tension effects at free surface. Also models wall adhesion effects. Written in FORTRAN 77.

  12. Surface-enhanced Raman microspectroscopy at electrode surfaces

    SciTech Connect

    Hembree D.M. Jr.; Oswald, J.C.; Smyrl, N.R.

    1987-02-01

    Surface-enhanced Raman microspectroscopy has been developed as a technique for characterizing processes occurring at the electrode/electrolyte interface. A spectroelectrochemical cell was designed to obtain Raman spectra of electrochemical species with the use of microscope optics, which allowed unambiguous placement of laser focus at the electrode surface with spatial resolution on the order of 1 ..mu..m. It was also possible to visually inspect the surface morphology of the electrode with the use of the Raman microscope in the reflected-light mode. The capabilities of the spectroelectrochemical cell were demonstrated by observation of surface-enhanced Raman scattering (SERS) for a variety of model systems (pyridine, pyridinium ion, potassium cyanide) with the use of silver, copper, and nickel electrodes. The electrochemical behavior of a commercially important gold electroplating process is also reported.

  13. Elliptic surface grid generation on minimal and parametrized surfaces

    NASA Technical Reports Server (NTRS)

    Spekreijse, S. P.; Nijhuis, G. H.; Boerstoel, J. W.

    1995-01-01

    An elliptic grid generation method, which generates boundary conforming grids in a two dimensional physical space, is presented. The method is based on the composition of an algebraic and elliptic transformation. The composite mapping obeys the Poisson grid generation system with control functions specified by the algebraic transformation. It is shown that the grid generation on a minimal surface in a three dimensional space is equivalent to the grid generation in a two dimensional domain in physical space. A second elliptic grid generation method, which generates boundary conforming grids on smooth surfaces, is presented. Concerning surface modeling, it is shown that bicubic Hermit interpolation is an excellent method to generate a smooth surface crossing a discrete set of control points.

  14. Surface energy and surface tension at holes and cracks

    NASA Technical Reports Server (NTRS)

    Rajapakse, Y. D. S.

    1975-01-01

    The concept of surface tension and surface energy of solids was used by Griffith to obtain a criterion for the extension of cracks in brittle materials. Griffith, however, neglected the stresses due to the normal traction at the crack implied by the surface tension. A complete solution to the problem of an elliptic hole in an infinite plate with surface tension loading at the hole is given. Complex potentials are given in closed form in terms of elliptic integrals of the first, second, and third kinds. Stress distributions are studied. For a flat crack, the nature of the singularity at the tip is shown to be radically different from that usually encountered in fracture mechanics. The implications of our analysis for theories of fracture in brittle materials are discussed.

  15. Bioactive Surface Modification of Hydroxyapatite

    PubMed Central

    Okazaki, Yohei; Hiasa, Kyou; Yasuda, Keisuke; Nogami, Keisuke; Mizumachi, Wataru; Hirata, Isao

    2013-01-01

    The purpose of this study was to establish an acid-etching procedure for altering the Ca/P ratio of the nanostructured surface of hydroxyapatite (HAP) by using surface chemical and morphological analyses (XPS, XRD, SEM, surface roughness, and wettability) and to evaluate the in vitro response of osteoblast-like cells (MC3T3-E1 cells) to the modified surfaces. This study utilized HAP and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid solution for 10 minutes at 25°C, followed by rinsing 3 times with ultrapure water. The 30% phosphoric acid etching process that provided a Ca/P ratio of 1.50, without destruction of the grain boundary of HAP, was selected as a surface-modification procedure. Additionally, HAP treated by the 30% phosphoric acid etching process was stored under dry conditions at 25°C for 12 hours, and the Ca/P ratio approximated to 1.00 accidentally. The initial adhesion, proliferation, and differentiation (alkaline phosphatase (ALP) activity and relative mRNA level for ALP) of MC3T3-E1 cells on the modified surfaces were significantly promoted (P < 0.05 and 0.01). These findings show that the 30% phosphoric acid etching process for the nanostructured HAP surface can alter the Ca/P ratio effectively and may accelerate the initial adhesion, proliferation, and differentiation of MC3T3-E1 cells. PMID:23862150

  16. Monte Carlo surface flux tallies

    SciTech Connect

    Favorite, Jeffrey A

    2010-11-19

    Particle fluxes on surfaces are difficult to calculate with Monte Carlo codes because the score requires a division by the surface-crossing angle cosine, and grazing angles lead to inaccuracies. We revisit the standard practice of dividing by half of a cosine 'cutoff' for particles whose surface-crossing cosines are below the cutoff. The theory behind this approximation is sound, but the application of the theory to all possible situations does not account for two implicit assumptions: (1) the grazing band must be symmetric about 0, and (2) a single linear expansion for the angular flux must be applied in the entire grazing band. These assumptions are violated in common circumstances; for example, for separate in-going and out-going flux tallies on internal surfaces, and for out-going flux tallies on external surfaces. In some situations, dividing by two-thirds of the cosine cutoff is more appropriate. If users were able to control both the cosine cutoff and the substitute value, they could use these parameters to make accurate surface flux tallies. The procedure is demonstrated in a test problem in which Monte Carlo surface fluxes in cosine bins are converted to angular fluxes and compared with the results of a discrete ordinates calculation.

  17. Surface Power Radiative Cooling Tests

    SciTech Connect

    Vaughn, Jason; Schneider, Todd

    2006-01-20

    Terrestrial nuclear power plants typically maintain their temperature through convective cooling, such as water and forced air. However, the space environment is a vacuum environment, typically 10-8 Torr pressure, therefore in proposed missions to the lunar surface, power plants would have to rely on radiative cooling to remove waste heat. Also, the Martian surface has a very tenuous atmosphere (e.g. {approx}5 Torr CO2), therefore, the main heat transfer method on the Martian surface is also radiative. Because of the lack of atmosphere on the Moon and the tenuous atmosphere on Mars, surface power systems on both the Lunar and Martian surface must rely heavily on radiative heat transfer. Because of the large temperature swings on both the lunar and the Martian surfaces, trying to radiate heat is inefficient. In order to increase power system efficiency, an effort is underway to test various combinations of materials with high emissivities to demonstrate their ability to survive these degrading atmospheres to maintain a constant radiator temperature improving surface power plant efficiency. An important part of this effort is the development of a unique capability that would allow the determination of a materials emissivity at high temperatures. A description of the test capability as well as initial data is presented.

  18. Surface metrology by phase contrast

    NASA Astrophysics Data System (ADS)

    Baker, Lionel R.

    1990-08-01

    Increasing use of electrooptical imaging and detection systems in thermography high density information storage laser instrumentation and X-ray optics has led to a pressing need for machinecompatible sensors for the measurement of surface texture. This paper reviews recent advances in the use of deterministic and parametric noncontact methods for texture measurement and justifies the need for objective simple and yet precise means for displaying the microfinish of a machined surface. The design of a simple two channel phase contrast microscope is described which can be calibrated by test pieces and used as a means for optimising the process parameters involved in the generation of high quality surfaces. Typical results obtained with this technique including dynamic range and ultimate sensitivity are discussed. 1 . NEED FOR SURFACE METROLOGY Surface quality has a direct influence on product acceptability in many different industries including those concerned with optoelectronics and engineering. The influence may be cosmetic as with paint finish on a motor car body or functional for example when excessive wear rates may occur in a bearing surface with inadequate oil retention. Since perfection can never be achieved and overspecification can be costly it is clearly necessary to be able to define thresholds of acceptance in relation to different situations. Such thresholds do of course require agreed methods of measurement with traceability to national standards. The current trends in surface metrology are towards higher

  19. Surface Power Radiative Cooling Tests

    NASA Astrophysics Data System (ADS)

    Vaughn, Jason; Schneider, Todd

    2006-01-01

    Terrestrial nuclear power plants typically maintain their temperature through convective cooling, such as water and forced air. However, the space environment is a vacuum environment, typically 10-8 Torr pressure, therefore in proposed missions to the lunar surface, power plants would have to rely on radiative cooling to remove waste heat. Also, the Martian surface has a very tenuous atmosphere (e.g. ~5 Torr CO2), therefore, the main heat transfer method on the Martian surface is also radiative. Because of the lack of atmosphere on the Moon and the tenuous atmosphere on Mars, surface power systems on both the Lunar and Martian surface must rely heavily on radiative heat transfer. Because of the large temperature swings on both the lunar and the Martian surfaces, trying to radiate heat is inefficient. In order to increase power system efficiency, an effort is underway to test various combinations of materials with high emissivities to demonstrate their ability to survive these degrading atmospheres to maintain a constant radiator temperature improving surface power plant efficiency. An important part of this effort is the development of a unique capability that would allow the determination of a materials emissivity at high temperatures. A description of the test capability as well as initial data is presented.

  20. Mars Surface Tunnel Element Concept

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.; Mary, Natalie; Howe, A. Scott; Jeffries, Sharon

    2016-01-01

    How Mars surface crews get into their ascent vehicle has profound implications for Mars surface architecture. To meet planetary protection protocols, the architecture has get Intravehicular Activity (IVA)-suited crew into a Mars Ascent Vehicle (MAV) without having to step outside into the Mars environment. Pushing EVA suit don/doff and EVA operations to an element that remains on the surface also helps to minimize MAV cabin volume, which in turn can reduce MAV cabin mass. Because the MAV will require at least seven kilograms of propellant to ascend each kilogram of cabin mass, minimal MAV mass is desired. For architectures involving more than one surface element-such as an ascent vehicle and a pressurized rover or surface habitat-a retractable tunnel is an attractive solution. Beyond addressing the immediate MAV access issue, a reusable tunnel may be useful for other surface applications once its primary mission is complete. A National Aeronautics and Space Administration (NASA) team is studying the optimal balance between surface tunnel functionality, mass, and stowed volume as part of the Evolvable Mars Campaign (EMC). The "Minimum Functional Tunnel" is a conceptual design that performs a single function. Having established this baseline configuration, the next step is to trade design options, evaluate other applications, and explore alternative solutions.

  1. Interpreting the probe-surface interaction of surface measuring instruments, or what is a surface?

    NASA Astrophysics Data System (ADS)

    Leach, Richard; Weckenmann, Albert; Coupland, Jeremy; Hartmann, Wito

    2014-09-01

    When using dimensional measuring instruments it is assumed that there is a property of the object, which we call surface, that is present before during and after the measurement, i.e. the surface is a fundamental property of an object that can, by appropriate means, be used to measure geometry. This paper will attempt to show that the fundamental property ‘surface’ does not exist in any simple form and that all the information we can have about a surface is the measurement data, which will include measurement uncertainty. Measurement data, or what will be referred to as the measured surface, is all that really exists. In this paper the basic physical differences between mechanically, electromagnetically and electrically measured surfaces are highlighted and discussed and accompanied by measurement results on a roughness artefact.

  2. Fabrication of durable hydrophobic surfaces through surface texturing

    NASA Astrophysics Data System (ADS)

    Beckford, Samuel; Langston, Nicholas; Zou, Min; Wei, Ronghua

    2011-04-01

    Low surface energy polymer thin-films can be applied to surfaces to increase hydrophobicity and reduce friction for a variety of applications. However, wear of these thin films, resulting from repetitive rubbing against another surface, is of great concern. In this study, we show that highly hydrophobic surfaces with persistent abrasion resistance can be fabricated by depositing fluorinated carbon thin films on sandblasted glass surfaces. In our study, fluorinated carbon thin films were deposited on sandblasted and as-received smooth glass using deep reactive ion etching equipment by only activating the passivation step. The surfaces of the samples were then rubbed with FibrMet abrasive papers in a reciprocating motion using an automatic friction abrasion analyzer. During the rubbing, the static and kinetic friction forces were also measured. The surface wetting properties were then characterized using a video-based contact angle measuring system to determine the changes in water contact angle as a result of rubbing. Assessment of the wear properties of the thin films was based on the changes in the water contact angles of the coated surfaces after repetitive rubbing. It was found that, for sandblasted glass coated with fluorinated carbon film, the water contact angle remained constant throughout the entire rubbing process, contrary to the smooth glass coated with fluorinated carbon film which showed a drastic decrease in water contact angle with the increasing number of rubbing cycles. In addition, the static and kinetic friction coefficients of the sandblasted glass were also much lower than those of the smooth glass.

  3. Globally optimal surface mapping for surfaces with arbitrary topology.

    PubMed

    Li, Xin; Bao, Yunfan; Guo, Xiaohu; Jin, Miao; Gu, Xianfeng; Qin, Hong

    2008-01-01

    Computing smooth and optimal one-to-one maps between surfaces of same topology is a fundamental problem in computer graphics and such a method provides us a ubiquitous tool for geometric modeling and data visualization. Its vast variety of applications includes shape registration/matching, shape blending, material/data transfer, data fusion, information reuse, etc. The mapping quality is typically measured in terms of angular distortions among different shapes. This paper proposes and develops a novel quasi-conformal surface mapping framework to globally minimize the stretching energy inevitably introduced between two different shapes. The existing state-of-the-art inter-surface mapping techniques only afford local optimization either on surface patches via boundary cutting or on the simplified base domain, lacking rigorous mathematical foundation and analysis. We design and articulate an automatic variational algorithm that can reach the global distortion minimum for surface mapping between shapes of arbitrary topology, and our algorithm is sorely founded upon the intrinsic geometry structure of surfaces. To our best knowledge, this is the first attempt towards numerically computing globally optimal maps. Consequently, our mapping framework offers a powerful computational tool for graphics and visualization tasks such as data and texture transfer, shape morphing, and shape matching. PMID:18467756

  4. Surface Wrinkling on Polydimethylsiloxane Microspheres via Wet Surface Chemical Oxidation

    PubMed Central

    Yin, Jian; Han, Xue; Cao, Yanping; Lu, Conghua

    2014-01-01

    Here we introduce a simple low-cost yet robust method to realize spontaneously wrinkled morphologies on spherical surfaces. It is based on surface chemical oxidation of aqueous-phase-synthesized polydimethylsiloxane (PDMS) microspheres in the mixed H2SO4/HNO3/H2O solution. Consequently, curvature and overstress-sensitive wrinkles including dimples and labyrinth patterns are successfully induced on the resulting oxidized PDMS microspheres. A power-law dependence of the wrinkling wavelength on the microsphere radius exists. The effects of experimental parameters on these tunable spherical wrinkles have been systematically investigated, when the microspheres are pre-deposited on a substrate. These parameters include the radius and modulus of microspheres, the mixed acid solution composition, the oxidation duration, and the water washing post-treatment. Meanwhile, the complicated chemical oxidation process has also been well studied by in-situ optical observation via the microsphere system, which represents an intractable issue in a planar system. Furthermore, we realize surface wrinkled topographies on the whole microspheres at a large scale, when microspheres are directly dispersed in the mixed acid solution for surface oxidation. These results indicate that the introduced wet surface chemical oxidation has the great potential to apply to other complicated curved surfaces for large-scale generation of well-defined wrinkling patterns, which endow the solids with desired physical properties. PMID:25028198

  5. Elliptic surface grid generation on minimal and parmetrized surfaces

    NASA Technical Reports Server (NTRS)

    Spekreijse, S. P.; Nijhuis, G. H.; Boerstoel, J. W.

    1995-01-01

    An elliptic grid generation method is presented which generates excellent boundary conforming grids in domains in 2D physical space. The method is based on the composition of an algebraic and elliptic transformation. The composite mapping obeys the familiar Poisson grid generation system with control functions specified by the algebraic transformation. New expressions are given for the control functions. Grid orthogonality at the boundary is achieved by modification of the algebraic transformation. It is shown that grid generation on a minimal surface in 3D physical space is in fact equivalent to grid generation in a domain in 2D physical space. A second elliptic grid generation method is presented which generates excellent boundary conforming grids on smooth surfaces. It is assumed that the surfaces are parametrized and that the grid only depends on the shape of the surface and is independent of the parametrization. Concerning surface modeling, it is shown that bicubic Hermite interpolation is an excellent method to generate a smooth surface which is passing through a given discrete set of control points. In contrast to bicubic spline interpolation, there is extra freedom to model the tangent and twist vectors such that spurious oscillations are prevented.

  6. Fermi Surfaces of Surface States on Si(111)

    NASA Astrophysics Data System (ADS)

    Crain, J. N.; Altmann, K. N.; Himpsel, F. J.; Bromberger, C.

    2002-03-01

    Metallic surface states on semi-conducting surfaces provide a unique opportunity to study low-dimensional bands that are decoupled from the bulk. Two such systems that have received much attention for their metallic surface states are Si(111)surd 3× surd 3 - Ag and Si(111) surd 3× surd 3 - Au. We present angle resolved photoemission data mapping the Fermi-surfaces for surd 3× surd 3 - Ag and surd 3× surd 3 - Au, and study the effects of doping the surface with additional Au atoms.[1] For surd 3× surd 3 - Au, an increase in the Au coverage is linked to an increase in the occupancy of the metallic surface state. In the case of surd 3× surd 3 - Ag, the addition of Au forms a new metallic band and a surd 21× surd 21 superlattice that are observed in photoemission. Reference: [1] J N Crain, K N Altmann, C Bromberger, F J Himpsel, submitted to Physics Review B.

  7. Venus - Global surface radio emissivity

    NASA Technical Reports Server (NTRS)

    Ford, P. G.; Pettengill, G. H.

    1983-01-01

    Observations of thermal radio emission from the surface of Venus, made by the Pioneer Venus radar mapper at a wavelength of 17 cm, show variations that are dominated by changes in surface emissivity. The regions of lowest emissivity (0.54 + or - 0.05 for the highland areas of Aphrodite Terra and Theia Mons) correspond closely to regions of high radar reflectivity reported earlier. These results support the inference of inclusions of material with high electrical conductivity in the surface rock of these areas.

  8. Undergraduate Laboratory for Surface Science

    NASA Astrophysics Data System (ADS)

    Okumura, Mitchio; Beauchamp, Jesse L.; Dickert, Jeffrey M.; Essy, Blair R.; Claypool, Christopher L.

    1996-02-01

    Surface science has developed into a multidisciplinary field of research with applications ranging from heterogeneous catalysis to semiconductor etching (1). Aspects of surface chemistry are now included in physical chemistry textbooks (2) and undergraduate curricula (3), but the perceived cost and complexity of equipment has deterred the introduction of surface science methods in undergraduate laboratories (4). Efforts to expose chemistry undergraduates to state-of-the-art surface instrumentation have just begun (5). To provide our undergraduates with hands-on experience in using standard techniques for characterizing surface morphology, adsorbates, kinetics, and reaction mechanisms, we have developed a set of surface science experiments for our physical chemistry laboratory sequence. The centerpiece of the laboratory is an ultrahigh vacuum (UHV) chamber for studies of single crystal surfaces. This instrument, shown in the figure, has surface analysis capabilities including low energy electron diffraction (LEED), Auger spectroscopy, and temperature-programmed desorption (TPD). The laboratory exercises involve experiments on the well-studied Pt(111) surface. Students prepare a previously mounted single crystal sample by sputtering it with an argon ion gun and heating it under O2. Electron diffraction patterns from the cleaned surface are then obtained with a reverse view LEED apparatus (Princeton Instruments). Images are captured by a charge-coupled device (CCD) camera interfaced to a personal computer for easy downloading and subsequent analysis. Although the LEED images from a Pt(111) surface can be readily interpreted using simple diffraction arguments, this lab provides an excellent context for introducing Miller indices and reciprocal lattices (6). The surface chemical composition can be investigated by Auger spectroscopy, using the LEED apparatus as a simple energy analyzer. The temperature programmed desorption experiment, which is nearly complete, will be

  9. Statistical thermodynamics of soft surfaces

    NASA Astrophysics Data System (ADS)

    Safran, S. A.

    2002-03-01

    We review the continuum, statistical thermodynamics of surfaces and interfaces in soft matter where both the energy and entropy of the surface are comparable. These systems include complex fluids that are dominated by either surface tension or the interfacial curvature, such as: fluid and solid interfaces, colloidal dispersions, macromolecular solutions, membranes, and other self-assembling aggregates such as micelles, vesicles, and microemulsions. The primary focus is on the theoretical concepts, their universality, and the role of fluctuations and inhomogeneities with connections to relevant experimental systems.

  10. Exoelectron emission from magnesium surfaces

    NASA Astrophysics Data System (ADS)

    Klar, F.; Bansmann, J.; Glaefeke, H.; Fitting, H.-J.; Meiwes-Broer, K.-H.

    1999-12-01

    Clean magnesium surfaces were created by evaporating Mg onto silicon wafers. When exposing the Mg surface to a low oxygen partial pressure, an exoelectron emission (EEE) is observed after a time delay of the order of several hours after evaporation. On a much shorter time scale, similar effects in exoemission from Mg and alkali metals have been observed previously. The results are discussed within a 'potential emission' model of exoelectrons during oxygen capture at the pure Mg surface, but extending the model by including an escape mechanism. A macroscopic quantitative description of the model is given, which is in good agreement with our measurements.

  11. Instruments Sniff Organic Surface Contaminants

    NASA Technical Reports Server (NTRS)

    Adler-Golden, Steven; Matthew, Michael W.

    1995-01-01

    Portable instruments detecting both nonvolatile and volatile organic surface contaminants in real time developed. Instruments easy to use: operate under ordinary ambient atmospheric conditions, without need to use messy liquid solvents or install and remove witness plates, and without need to cut specimens from surfaces to be inspected. Principle of detection involves sweeping pure, activated gas across surface spot inspected, then monitoring light emitted at wavelengths characteristic of excited molecules formed by chemical reactions between activated gas and contaminants. Gas activated by dc discharge, radio-frequency induction, microwave radiation, laser beam, hot filaments, or any other suitable means that excites some of gas molecules.

  12. Nanofluidic mixing via hybrid surface

    SciTech Connect

    Ye, Ziran; Li, Shunbo; Zhou, Bingpu; Hui, Yu Sanna; Shen, Rong; Wen, Weijia

    2014-10-20

    We report the design and fabrication of the nanofluidic mixer comprising hybrid hydrophobic/hydrophilic micro-patterns on the top and bottom walls of the nanochannel. The unique feature of such mixer is that, without any geometric structure inside the nanochannel, the mixing can be realized solely by the hybrid surfaces. Besides, the mixing length in nanomixer has been significantly shortened comparing to micromixer. We attribute the mixing achievement to be caused by the convection and chaotic flows of two fluids along the hybrid surface due to the large surface-to-volume ratio of the nanochannel.

  13. Surface diagnostics for scale analysis.

    PubMed

    Dunn, S; Impey, S; Kimpton, C; Parsons, S A; Doyle, J; Jefferson, B

    2004-01-01

    Stainless steel, polymethylmethacrylate and polytetrafluoroethylene coupons were analysed for surface topographical and adhesion force characteristics using tapping mode atomic force microscopy and force-distance microscopy techniques. The two polymer materials were surface modified by polishing with silicon carbide papers of known grade. The struvite scaling rate was determined for each coupon and related to the data gained from the surface analysis. The scaling rate correlated well with adhesion force measurements indicating that lower energy materials scale at a lower rate. The techniques outlined in the paper provide a method for the rapid screening of materials in potential scaling applications. PMID:14982180

  14. Embedded fiducials in optical surfaces

    DOEpatents

    Sommargren, Gary E.

    2000-01-01

    Embedded fiducials are provided in optical surfaces and a method for embedding the fiducials. Fiducials, or marks on a surface, are important for optical fabrication and alignment, particularly when individual optical elements are aspheres. Fiducials are used during the course of the polishing process to connect interferometric data, and the equation describing the asphere, to physical points on the optic. By embedding fiducials below the surface of the optic and slightly outside the clear aperture of the optic, the fiducials are not removed by polishing, do not interfere with the polishing process, and do not affect the performance of the finished optic.

  15. Embedded fiducials in optical surfaces

    SciTech Connect

    Sommargren, G.E.

    2000-01-11

    Embedded fiducials are provided in optical surfaces and a method for embedding the fiducials. Fiducials, or marks on a surface, are important for optical fabrication and alignment, particularly when individual optical elements are aspheres. Fiducials are used during the course of the polishing process to connect interferometric data, and the equation describing the asphere, to physical points on the optic. By embedding fiducials below the surface of the optic and slightly outside the clear aperture of the optic, the fiducials are not removed by polishing, do not interfere with the polishing process, and do not affect the performance of the finished optic.

  16. Simulation of Nematic Free Surfaces

    NASA Astrophysics Data System (ADS)

    de Miguel, Enrique; Martín del Río, Elvira

    Molecular dynamics and Monte Carlo methods are applied to study the liquid free surfaces in model liquid crystals. The simulation results suggest that the attractive interactions promote parallel alignment of the molecules at the nematic free surface in the Gay-Berne model, in agreement with theoretical predictions. A change in the orientation from planar to homeotropic is observed and explained in terms of a competing effect between attractive and repulsive interactions. Finally, the simulation results give clear evidence that the hard-core repulsions favor homeotropic orientation at the nematic free surface, in agreement with most theories.

  17. Particle tracking around surface nanobubbles

    NASA Astrophysics Data System (ADS)

    Dietrich, Erik; Zandvliet, Harold J. W.; Lohse, Detlef; Seddon, James R. T.

    2013-05-01

    The exceptionally long lifetime of surface nanobubbles remains one of the biggest questions in the field. One of the proposed mechanisms for producing the stability is the dynamic equilibrium model, which describes a constant flux of gas in and out of the bubble. Here, we describe results from particle tracking experiments carried out to measure this flow. The results are analysed by measuring the Voronoï cell size distribution, the diffusion, and the speed of the tracer particles. We show that there is no detectable difference in the movement of particles above nanobubble-laden surfaces as compared to ones above nanobubble-free surfaces.

  18. Conveyorized applications to surface mining

    SciTech Connect

    Peterson, A.N.

    1983-06-01

    Worldwide, there are numerous conveyorized surface mines successfully operating today. Each surface mine is unique and requires a custom made system which ideally begins as part of the mine development plan. When properly applied, conveyorized systems can offer major cost savings in both capital costs and operating and maintenance costs. With modern technology, both required availability and flexibility have been satisfied on the many currently operating mines. Conveyorized systems offer a valuable ''tool'' which when combined with the other proven mining technology results in the most efficient surface mine operations which spells lower costs and higher profits.

  19. Mapping products of Titan's surface

    USGS Publications Warehouse

    Stephan, Katrin; Jaumann, Ralf; Karkoschka, Erich; Barnes, Jason W.; Tomasko, Martin G.; Turtle, Elizabeth P.; Le Corre, Lucille; Langhans, Mirjam; Le Mouelic, Stephane; Lorenz, Ralf D.; Perry, Jason

    2009-01-01

    Remote sensing instruments aboard the Cassini spacecraft have been observed the surface of Titan globally in the infrared and radar wavelength ranges as well as locally by the Huygens instruments revealing a wealth of new morphological features indicating a geologically active surface. We present a summary of mapping products of Titan's surface derived from data of the remote sensing instruments onboard the Cassini spacecraft (ISS, VIMS, RADAR) as well as the Huygens probe (DISR) that were achieved during the nominal Cassini mission including an overview of Titan's recent nomenclature.

  20. Surface parametrization and shape description

    NASA Astrophysics Data System (ADS)

    Brechbuehler, Christian; Gerig, Guido; Kuebler, Olaf

    1992-09-01

    Procedures for the parameterization and description of the surface of simply connected 3-D objects are presented. Critical issues for shape-based categorization and comparison of 3-D objects are addressed, which are generality with respect to object complexity, invariance to standard transformations, and descriptive power in terms of object geometry. Starting from segmented volume data, a relational data structure describing the adjacency of local surface elements is generated. The representation is used to parametrize the surface by defining a continuous, one-to-one mapping from the surface of the original object to the surface of a unit sphere. The mapping is constrained by two requirements, minimization of distortions and preservation of area. The former is formulated as the goal function of a nonlinear optimization problem and the latter as its constraints. Practicable starting values are obtained by an initial mapping based on a heat conduction model. In contract to earlier approaches, the novel parameterization method provides a mapping of arbitrarily shaped simply connected objects, i.e., it performs an unfolding of convoluted surface structures. This global parameterization allows the systematical scanning of the object surface by the variation of two parameters. As one possible approach to shape analysis, it enables us to expand the object surface into a series of spherical harmonic functions, extending the concept of elliptical Fourier descriptors for 2-D closed curves. The novel parameterization overcomes the traditional limitations of expressing an object surface in polar coordinates, which restricts such descriptions to star-shaped objects. The numerical coefficients in the Fourier series form an object-centered, surface-oriented descriptor of the object''s form. Rotating the coefficients in parameter space and object space puts the object into a standard position and yields a spherical harmonic descriptor which is invariant to translations, rotations

  1. Supersonic transport. [using canard surfaces

    NASA Technical Reports Server (NTRS)

    Coe, P. L., Jr. (Inventor)

    1978-01-01

    An aircraft of supersonic transport configuration is described, featuring thrust vectoring in conjunction with wing apex segments used as canard surfaces during takeoff, landing, and low-speed flight. The angle of incidence of the wing apex segments, when the segments were functioning as canard surfaces, was variable with respect to the aircraft angle of attack. The wing apex segments furthermore formed a portion of the main wing panel swept leading edge when not functioning as canard surfaces. The combination of thrust vectoring and deployable wing apex segments resulted in increased aircraft range and improved low speed longitudinal stability while providing acceptable takeoff length capabilities.

  2. Surface wrinkling on polydopamine film

    NASA Astrophysics Data System (ADS)

    Meng, Jieyun; Xie, Jixun; Han, Xue; Lu, Conghua

    2016-05-01

    In this paper, we report a non-lithographic strategy to realize surface patterns on polydopamine films. It is based on surface wrinkling, which is induced on polydopamine (PDA) films that are grown on uniaxially pre-strained polydimethylsiloxane (PDMS) substrates through self-polymerization of dopamine, followed by the pre-strain release. We investigate the influences of the experimental conditions including polymerization time, prestrain and the dopamine solution concentration on the wrinkling patterns. Furthermore, we take advantage of the reducibility of PDA to fabricate silver nanoparticle-deposited PDA films with surface-wrinkled patterns, which may have potential applications in the related fields.

  3. TOPICAL REVIEW: Magnetic surface nanostructures

    NASA Astrophysics Data System (ADS)

    Enders, A.; Skomski, R.; Honolka, J.

    2010-11-01

    Recent trends in the emerging field of surface-supported magnetic nanostructures are reviewed. Current strategies for nanostructure synthesis are summarized, followed by a predominantly theoretical description of magnetic phenomena in surface magnetic structures and a review of experimental research in this field. Emphasis is on Fe- or Co-based nanostructures in various low-dimensional geometries, which are studied as model systems to explore the effects of dimensionality, atomic coordination, chemical bonds, alloying and, most importantly, interactions with the supporting substrate on the magnetism. This review also includes a discussion of closely related systems, such as 3d element impurities integrated into organic networks, surface-supported Fe-based molecular magnets, Kondo systems or 4d element nanostructures that exhibit emergent magnetism, thereby bridging the traditional areas of surface science, molecular physics and nanomagnetism.

  4. Surface Tension and Capillary Rise

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1972-01-01

    Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

  5. Sustaining dry surfaces under water.

    PubMed

    Jones, Paul R; Hao, Xiuqing; Cruz-Chu, Eduardo R; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M; Varanasi, Kripa K; Megaridis, Constantine M; Walther, Jens H; Koumoutsakos, Petros; Espinosa, Horacio D; Patankar, Neelesh A

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  6. Lunar surface magnetometer design review

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Design and fabrication parameters of a lunar surface magnetometer are discussed. Drawings and requirements for mechanical design, electronic packaging design, thermal design, quality assurance and systems testing are included.

  7. Measuring Roughnesses Of Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Coulter, Daniel R.; Al-Jumaily, Gahnim A.; Raouf, Nasrat A.; Anderson, Mark S.

    1994-01-01

    Report discusses use of scanning tunneling microscopy and atomic force microscopy to measure roughnesses of optical surfaces. These techniques offer greater spatial resolution than other techniques. Report notes scanning tunneling microscopes and atomic force microscopes resolve down to 1 nm.

  8. Tribological applications of surface analysis

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1984-01-01

    For some years, surface analysis was used in fundamental studies of solid-solid contacts existing in tribological systems. Analysis was used to detect material transfer in sliding contacts. The effects of surface films on the adhesion of contacts was monitored. Finally electron spectroscopic analysis of interfaces has shed some light on the fundamental electronic nature of the interfacial bond. More recently, surface analysis was applied to many tribological engineering problems. In particular, identification of chemical films formed during the sliding contact of lubricated systems and study of the surface chemistry of lubricant additives were active areas of research. One or more of four properties of the analytical technique will be important in determining its utility. The four are: lateral resolution, specimen damage, depth resolution and the availability of chemical information. In each of the applications discussed here, the important factors are brought out.

  9. Airport surface operations requirements analysis

    NASA Technical Reports Server (NTRS)

    Groce, John L.; Vonbokern, Greg J.; Wray, Rick L.

    1993-01-01

    This report documents the results of the Airport Surface Operations Requirements Analysis (ASORA) study. This study was conducted in response to task 24 of NASA Contract NAS1-18027. This study is part of NASA LaRC's Low Visibility Surface Operations program, which is designed to eliminate the constraints on all-weather arrival/departure operations due to the airport/aircraft ground system. The goal of this program is to provide the capability for safe and efficient aircraft operations on the airport surface during low visibility conditions down to zero. The ASORA study objectives were to (1) develop requirements for operation on the airport surface in visibilities down to zero; (2) survey and evaluate likely technologies; (3) develop candidate concepts to meet the requirements; and (4) select the most suitable concept based on cost/benefit factors.

  10. Temperature-dependent Luttinger surfaces.

    PubMed

    Ito, T; Chainani, A; Haruna, T; Kanai, K; Yokoya, T; Shin, S; Kato, R

    2005-12-01

    The Luttinger surface of an organic metal (TTF-TCNQ), possessing charge order and spin-charge separated band dispersions, is investigated using temperature-dependent angle-resolved photoemission spectroscopy. The Luttinger surface topology, obtained from momentum distribution curves, changes from quasi-2D (dimensional) to quasi-1D with temperature. The high temperature quasi-2D surface exhibits 4kF charge-density-wave (CDW) superstructure in the TCNQ derived holon band, in the absence of 2kF order. Decreasing temperature results in quasi-1D nested 2kF CDW order in the TCNQ spinon band and in the TTF surface. The results establish the link in momentum space between charge order and spin-charge separation in a Luttinger liquid. PMID:16384402

  11. Silicide surface phases on gold

    NASA Technical Reports Server (NTRS)

    Green, A. K.; Bauer, E.

    1981-01-01

    The crystalline silicide layers formed on (111) and (100) surfaces of Au films on various Si single-crystal substrates are studied by LEED and AES in conjunction with sputter-depth profiling as a function of annealing temperature. On the (111) surface, three basic silicide structures are obtained corresponding to layers of various thicknesses as obtained by different preparation conditions. The (100) surface shows only two different structures. None of the structures is compatible with the various bulk silicide structures deduced from X-ray diffraction. Using LEED as a criterion for the presence or absence of silicide on the surface, smaller layer thicknesses are obtained than reported previously on the basis of AES studies.

  12. Air entrainment in hairy surfaces

    NASA Astrophysics Data System (ADS)

    Nasto, Alice; Regli, Marianne; Brun, P.-T.; Alvarado, José; Clanet, Christophe; Hosoi, A. E.

    2016-07-01

    Motivated by diving semiaquatic mammals, we investigate the mechanism of dynamic air entrainment in hairy surfaces submerged in liquid. Hairy surfaces are cast out of polydimethylsiloxane elastomer and plunged into a fluid bath at different velocities. Experimentally, we find that the amount of air entrained is greater than what is expected for smooth surfaces. Theoretically, we show that the hairy surface can be considered as a porous medium and we describe the air entrainment via a competition between the hydrostatic forcing and the viscous resistance in the pores. A phase diagram that includes data from our experiments and biological data from diving semiaquatic mammals is included to place the model system in a biological context and predict the regime for which the animal is protected by a plastron of air.

  13. Hydrophobicity of curved microstructured surfaces

    NASA Astrophysics Data System (ADS)

    Cannon, A. H.; King, W. P.

    2010-02-01

    This paper presents measurements and models for how the macroscopic curvature of microstructured polymers affects hydrophobicity. Flexible polymer substrates were fabricated with arrays of regular microstructures. The interaction of liquid drops with these surfaces was analyzed for flat substrates and substrates flexed into either positive or negative cylindrical shapes. Liquid droplet static contact angle and dynamic slide angle were measured for a range of surfaces. An increase in substrate curvature corresponded with decreased slide angle for liquid droplets suspended on the surface asperities. This phenomenon is investigated in terms of solid-liquid contact line and the periodicity of surface microstructures. We present a model that can be used to understand the observed phenomena and to design microstructure geometries for hydrophobicity.

  14. Surface disordering of Pb(110)

    NASA Technical Reports Server (NTRS)

    Tibbits, P.; Karimi, M.; Ila, D.; Dalins, I.; Vidali, G.

    1991-01-01

    A molecular dynamics simulation of Pb(110), using embedded atom method energy functional and two-body potential derived for the purpose, shows that near 400 K the three surface layers begin to disorder well before the bulk (interior) layers. Transfer of atoms from the first subsurface layer to the surface layer occurs. Disordering propagates beyond the top three layers above 550 K, accompanied by formation of an adlayer and vacancies in the top three layers. Behavior of the two-dimensional layer structure factors indicates that disordering is anisotropic. Simulation results are consistent with experimental observations of surface roughening near 400 K and more extensive surface ordering above 525 K. Results are consistent with simulations for Ni and Al.

  15. Surface treatment of ceramic articles

    DOEpatents

    Komvopoulos, Kyriakos; Brown, Ian G.; Wei, Bo; Anders, Simone; Anders, Andre; Bhatia, C. Singh

    1998-01-01

    A process for producing an article with improved ceramic surface properties including providing an article having a ceramic surface, and placing the article onto a conductive substrate holder in a hermetic enclosure. Thereafter a low pressure ambient is provided in the hermetic enclosure. A plasma including ions of solid materials is produced the ceramic surface of the article being at least partially immersed in a macroparticle free region of the plasma. While the article is immersed in the macroparticle free region, a bias of the substrate holder is biased between a low voltage at which material from the plasma condenses on the surface of the article and a high negative voltage at which ions from the plasma are implanted into the article.

  16. Surface treatment of ceramic articles

    DOEpatents

    Komvopoulos, K.; Brown, I.G.; Wei, B.; Anders, S.; Anders, A.; Bhatia, C.S.

    1998-12-22

    A process is disclosed for producing an article with improved ceramic surface properties including providing an article having a ceramic surface, and placing the article onto a conductive substrate holder in a hermetic enclosure. Thereafter a low pressure ambient is provided in the hermetic enclosure. A plasma including ions of solid materials is produced the ceramic surface of the article being at least partially immersed in a macroparticle free region of the plasma. While the article is immersed in the macroparticle free region, a bias of the substrate holder is biased between a low voltage at which material from the plasma condenses on the surface of the article and a high negative voltage at which ions from the plasma are implanted into the article. 15 figs.

  17. Sustaining dry surfaces under water

    PubMed Central

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  18. Design Surfaces by Laser Remelting

    NASA Astrophysics Data System (ADS)

    Temmler, André; Willenborg, Edgar; Wissenbach, Konrad

    The surface of a part or product strongly influences its properties and functions. These are, e.g., abrasion and corrosion resistance, insensitivity to scratches, haptics as well as the visual impression to the customer. Therefore, many plastic parts have structured surfaces like leather textures on car dashboards. Usually these structures are integrated in the injection mould for the production of the plastic parts and then transferred to the plastic parts during the injection moulding process. A new approach to structuring metallic surfaces with laser radiation is structuring by remelting. Another approach of enhancing the appearance of design surfaces is creating a two-gloss effect by selective laser polishing. Both laser-based processes are based on reallocation of material instead of ablation.

  19. SURFACE CONTAINMENT FOR GEOTHERMAL BRINES

    EPA Science Inventory

    This report examines the probability of significant releases of geothermal brine to the surface environment through unplanned or accidental events. It then evaluates the containment measures that may be used to prevent environmental damage. The results indicate that major spills ...

  20. Surface morphology of erbium silicide

    NASA Technical Reports Server (NTRS)

    Lau, S. S.; Pai, C. S.; Wu, C. S.; Kuech, T. F.; Liu, B. X.

    1982-01-01

    The surface of rare-earth silicides (Er, Tb, etc.), formed by the reaction of thin-film metal layers with a silicon substrate, is typically dominated by deep penetrating, regularly shaped pits. These pits may have a detrimental effect on the electronic performance of low Schottky barrier height diodes utilizing such silicides on n-type Si. This study suggests that contamination at the metal-Si or silicide-Si interface is the primary cause of surface pitting. Surface pits may be reduced in density or eliminated entirely through either the use of Si substrate surfaces prepared under ultrahigh vacuum conditions prior to metal deposition and silicide formation or by means of ion irradiation techniques. Silicide layers formed by these techniques possess an almost planar morphology.

  1. Indium Second-Surface Mirrors

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.; Hasegawa, T.

    1982-01-01

    Second-surface mirrors are formed by vapor deposition of indium onto glass. Mirrors have reflectances comparable to those of ordinary silver or aluminized mirrors and are expected to show superior corrosion resistance. Mirrors may be used in solar concentrators.

  2. Surface Segregation in Multicomponent Systems: Modeling of Surface Alloys and Alloy Surfaces

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Ferrante, John; Noebe, Ronald D.; Good, Brian; Honecy, Frank S.; Abel, Phillip

    1999-01-01

    The study of surface segregation, although of great technological importance, has been largely restricted to experimental work due to limitations associated with theoretical methods. However, recent improvements in both first-particle and semi-empirical methods are opening, the doors to an array of new possibilities for surface scientists. We apply one of these techniques, the Bozzolo, Ferrante and Smith (BFS) method for alloys, which is particularly suitable for complex systems, to several aspects of the computational modeling of surfaces and segregation, including alloy surface segregation, structure and composition of alloy surfaces, and the formation of surface alloys. We conclude with the study of complex NiAl-based binary, ternary and quaternary thin films (with Ti, Cr and Cu additions to NiAl). Differences and similarities between bulk and surface compositions are discussed, illustrated by the results of Monte Carlo simulations. For some binary and ternary cases, the theoretical predictions are compared to experimental results, highlighting the accuracy and value of this developing theoretical tool.

  3. Bacterial Adhesion at Synthetic Surfaces

    PubMed Central

    Cunliffe, D.; Smart, C. A.; Alexander, C.; Vulfson, E. N.

    1999-01-01

    A systematic investigation into the effect of surface chemistry on bacterial adhesion was carried out. In particular, a number of physicochemical factors important in defining the surface at the molecular level were assessed for their effect on the adhesion of Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli. The primary experiments involved the grafting of groups varying in hydrophilicity, hydrophobicity, chain length, and chemical functionality onto glass substrates such that the surfaces were homogeneous and densely packed with functional groups. All of the surfaces were found to be chemically well defined, and their measured surface energies varied from 15 to 41 mJ · m−2. Protein adsorption experiments were performed with 3H-labelled bovine serum albumin and cytochrome c prior to bacterial attachment studies. Hydrophilic uncharged surfaces showed the greatest resistance to protein adsorption; however, our studies also showed that the effectiveness of poly(ethyleneoxide) (PEO) polymers was not simply a result of its hydrophilicity and molecular weight alone. The adsorption of the two proteins approximately correlated with short-term cell adhesion, and bacterial attachment for L. monocytogenes and E. coli also correlated with the chemistry of the underlying substrate. However, for S. aureus and S. typhimurium a different pattern of attachment occurred, suggesting a dissimilar mechanism of cell attachment, although high-molecular-weight PEO was still the least-cell-adsorbing surface. The implications of this for in vivo attachment of cells suggest that hydrophilic passivating groups may be the best method for preventing cell adsorption to synthetic substrates provided they can be grafted uniformly and in sufficient density at the surface. PMID:10543814

  4. Spectral Characteristics of Titan's Surface

    NASA Astrophysics Data System (ADS)

    Griffith, Caitlin A.; Turner, Jake D.; Penteado, Paulo; Khamsi, Tymon B.; Soderblom, Jason M.

    2014-11-01

    Cassini/Huygens and ground-based measurements of Titan reveal an eroded surface, with lakes, dunes, and sinuous washes. These features, coupled with measurements of clouds and rain, indicate the transfer of methane between Titan’s surface and atmosphere. The presence of methane-damp lowlands suggests further that the atmospheric methane (which is continually depleted through photolysis) may be supplied by sub-surface reservoirs. The byproducts of methane photolysis condense onto the surface, leaving layers of organic sediments that record Titan’s past atmospheres.Thus knowledge of the source and history of Titan's atmosphere requires measurements of the large scale compositional makeup of Titan's surface, which is shrouded by a thick and hazy atmosphere. Towards this goal, we analyzed roughly 100,000 spectra recorded by Cassini’s Visual and Infrared Mapping Spectrometer (VIMS). Our study is confined to the latitude region (20S—20N) surrounding the landing site of the Huygens probe (at 10S, 192W), which supplied only measurement of the vertical profiles of the methane abundance and haze scattering characteristics. VIMS near-IR spectral images indicate subtle latitudinal and temporal variations in the haze characteristics in the tropics. We constrain these small changes with full radiative transfer analyses of each of the thousands of VIMS spectra, which were recorded of different terrains and at different lighting conditions. The resulting models of Titan’s atmosphere as a function of latitude and year indicate the seasonal migration of Titan’s tropical haze and enable the derivation of Titan’s surface albedo at 8 near-IR wavelength regions where Titan’s atmosphere is transparent enough to allow visibility to the surface. The resultant maps of Titan’s surface indicate a number of terrain types with distinct spectral characteristics that are suggestive of atmospheric and surficial processes, including the deposition of organic material, erosion of

  5. SURFACE TREATMENT OF METALLIC URANIUM

    DOEpatents

    Gray, A.G.; Schweikher, E.W.

    1958-05-27

    The treatment of metallic uranium to provide a surface to which adherent electroplates can be applied is described. Metallic uranium is subjected to an etchant treatment in aqueous concentrated hydrochloric acid, and the etched metal is then treated to dissolve the resulting black oxide and/or chloride film without destroying the etched metal surface. The oxide or chloride removal is effected by means of moderately concentrated nitric acid in 3 to 20 seconds.

  6. Surface-Streamline Flow Visualization

    NASA Technical Reports Server (NTRS)

    Langston, L.; Boyle, M.

    1985-01-01

    Matrix of ink dots covers matte surface of polyester drafting film. Film placed against wind-tunnel wall. Layer of methyl salicylate (oil of wintergreen) sprayed over dotted area. Ink dot streaklines show several characteristics of flow, including primary saddle point of separations, primary horseshoe vortex and smaller vortex at cylinder/ endwall junction. Surface streamline flow visualization technique suitable for use in low-speed windtunnels or other low-speed gas flows.

  7. Surface analysis in composite bonding

    NASA Technical Reports Server (NTRS)

    Messick, D. L.; Wightman, J. P.

    1983-01-01

    X ray photoelectron spectroscopy and contact angle measurements on graphite fiber composites pretreated in a number of different ways including mechanical, chemical, and light irradiation were analyzed. Data acquired on surface contamination as a result of fabrication techniques provides answers to the strength and durability of adhesively bonded composites. These techniques were shown to provide valuable information on surface analysis of pretreated composites prior to adhesive bonding and following lap shear fracture.

  8. Surface inspection: Research and development

    NASA Technical Reports Server (NTRS)

    Batchelder, J. S.

    1987-01-01

    Surface inspection techniques are used for process learning, quality verification, and postmortem analysis in manufacturing for a spectrum of disciplines. First, trends in surface analysis are summarized for integrated circuits, high density interconnection boards, and magnetic disks, emphasizing on-line applications as opposed to off-line or development techniques. Then, a closer look is taken at microcontamination detection from both a patterned defect and a particulate inspection point of view.

  9. Insulating oxide surfaces and nanostructures

    NASA Astrophysics Data System (ADS)

    Goniakowski, Jacek; Noguera, Claudine

    2016-03-01

    This contribution describes some peculiarities of the science of oxide surfaces and nanostructures and proposes a simple conceptual scheme to understand their electronic structure, in the spirit of Jacques Friedel's work. Major results on the effects of non-stoichiometry and polarity are presented, for both semi-infinite surfaces and ultra-thin films, and promising lines of research for the near future are sketched. xml:lang="fr"

  10. Surface Water Records of Colorado

    USGS Publications Warehouse

    U.S. Geological Survey, Water Resources Division

    1962-01-01

    The surface-water records for the 1962 water year for gaging stations and miscellaneous sites within the State of Colorado are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of J. W. Odell, district engineer, Surface Water Branch.

  11. Corrosion-resistant metal surfaces

    DOEpatents

    Sugama, Toshifumi

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  12. Exploring the surface of Venus

    NASA Astrophysics Data System (ADS)

    Helbert, J.; Mueller, N. T.; Smrekar, S. E.; Piccioni, G.; Drossart, P.

    2009-12-01

    The VIRTIS instrument on the ESA mission Venus Express has produced the first in-orbit mapping of the surface of Venus using the atmospheric windows near 1 micron. Based on the data returned by VIRTIS a map of surface brightness variations could be obtained which are indicative of emissivity variations on the surface. The mapping in general indiactes three surface types, characterized by average, increased and decreased emissivity. These surface types show a good correlation with geological units identified by radar mapping. In general high emissivity units are found on very fresh lava flows, while tesserae terrain is typically associated with the low emissivity unit. This completely new dataset, that is highly complementary to the geological mapping based on radar data can provide significant support for the design and planning of future missions to Venus. For the first time there are strong indications for the heterogeneity of the surface composition of Venus. This is not only important for the selection of potential landing sites, but can provide important insights in the evolution of Venus. To support the mapping activity and the instrument development for future Venus missions we have started to obtain high temperature emissivity spectra of analog materials at Venus surface temperatures. This laboratory measurements will provide for the first time realistic near infrared spectral data for the surface of Venus. Obtaining data of samples at 500°C and taking emissivity measurements at 1 micron is a very challenging task. After more than 3 years of preparation the setup at the Planetary Emissivity Laboratory in Berlin is near completion and first test measurements have been obtained successfully.

  13. Mineralogy of the Mercurian Surface

    NASA Technical Reports Server (NTRS)

    Vander Kaaden, Kathleen E.; McCubbin, Francis M.; Nittler, Larry R.; Peplowski, Patrick N.; Weider, Shoshana Z.; Evans, Larry R.; Frank, Elizabeth A.; McCoy, Timothy

    2016-01-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited Mercury for four years until April 2015, revealing its structure, chemical makeup, and compositional diversity. Data from the mission have confirmed that Mercury is a compositional end-member among the terrestrial planets. The X-Ray Spectrometer (XRS) and Gamma-Ray Spectrometer (GRS) on board MESSENGER provided the first detailed geochemical analyses of Mercury's surface. These instruments have been used in conjunction with the Neutron Spectrometer and the Mercury Dual Imaging System to classify numerous geological and geochemical features on the surface of Mercury that were previously unknown. Furthermore, the data have revealed several surprising characteristics about Mercury's surface, including elevated S abundances (up to 4 wt%) and low Fe abundances (less than 2.5 wt%). The S and Fe abundances were used to quantify Mercury's highly reduced state, i.e., between 2.6 and 7.3 log10 units below the Iron-Wustite (IW) buffer. This fO2 is lower than any of the other terrestrial planets in the inner Solar System and has important consequences for the thermal and magmatic evolution of Mercury, its surface mineralogy and geochemistry, and the petrogenesis of the planet's magmas. Although MESSENGER has revealed substantial geochemical diversity across the surface of Mercury, until now, there have been only limited efforts to understand the mineralogical and petrological diversity of the planet. Here we present a systematic and comprehensive study of the potential mineralogical and petrological diversity of Mercury.

  14. Surface Information Loss in Comprehension

    PubMed Central

    Gernsbacher, Morton Ann

    2014-01-01

    Shortly after a sentence has been comprehended, information about its exact surface form (e.g., its word order) becomes less available. The present research demonstrated this phenomenon during the comprehension of nonverbal stimuli (picture stories). In Experiment 1, significantly more surface (left/right orientation) information was lost after comprehending several picture stories than just one; in Experiment 2, more was lost after comprehending an entire picture story than half of one. In Experiment 3, subjects segmented the picture stories into their constituents; in Experiment 4, significantly more surface information was lost after crossing these constituents’ boundaries than before. The present research also investigated why surface information is lost. Four explanations were considered: Surface information loss is the result of performing grammatical transformations (the linguistic hypothesis), exceeding short-term memory limitations (the memory limitations hypothesis), integrating information into gist (the integration hypothesis), shifting from building one substructure to initiating another (the processing shift hypothesis). The linguistic and memory limitations hypotheses were considered inadequate; the integration and the processing shift hypotheses were tested in the last set of experiments. In Experiment 5 (using nonverbal stimuli), the predictions made by the processing shift hypothesis were confirmed; in Experiment 6 (using verbal stimuli), these results were replicated. Other implications of the processing shift hypothesis concerning surface information loss are discussed. PMID:25308975

  15. Entropy of random entangling surfaces

    NASA Astrophysics Data System (ADS)

    Solodukhin, Sergey N.

    2012-09-01

    We consider the situation when a globally defined four-dimensional field system is separated on two entangled sub-systems by a dynamical (random) two-dimensional surface. The reduced density matrix averaged over ensemble of random surfaces of fixed area and the corresponding average entropy are introduced. The average entanglement entropy is analyzed for a generic conformal field theory in four dimensions. Two important particular cases are considered. In the first, both the intrinsic metric on the entangling surface and the spacetime metric are fluctuating. An important example of this type is when the entangling surface is a black hole horizon, the fluctuations of which cause necessarily the fluctuations in the spacetime geometry. In the second case, the spacetime is considered to be fixed. The detailed analysis is carried out for the random entangling surfaces embedded in flat Minkowski spacetime. In all cases, the problem reduces to an effectively two-dimensional problem of random surfaces which can be treated by means of the well-known conformal methods. Focusing on the logarithmic terms in the entropy, we predict the appearance of a new ln ln(A) term. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.

  16. Surface area controlled heterogeneous nucleation

    NASA Astrophysics Data System (ADS)

    Steer, Brian; Gorbunov, Boris; Rowles, Jonathan; Green, David

    2012-02-01

    Heterogeneous nucleation of liquid from a gas phase on nanoparticles has been studied under various saturation ratios and nuclei size. The probability of liquid droplet nucleation, especially at a low degree of deviation from equilibrium, was measured for both atmospheric aerosol particles and engineered nanoparticles Cr2O3. The concept of a critical saturation ratio and the validity of the one-to-one relationship between the nuclei number and the number of droplets were examined. A transient zone between no nucleation and established nucleation termed the surface area controlled nucleation was observed. In this zone, the probability of stable phase formation is determined by the surface area of nuclei. There are two distinctive features of the surface area controlled nucleation: the nucleation probability is much less than 1 and is proportional to the surface area of nuclei. For condensation particle counters (CPCs) counting nanoparticles, these features mean that counts measured are proportional to the surface area of nanoparticles and, therefore, the CPCs counts can be calibrated to measure the surface area.

  17. Surface physics of semiconducting nanowires

    NASA Astrophysics Data System (ADS)

    Amato, Michele; Rurali, Riccardo

    2016-02-01

    Semiconducting nanowires (NWs) are firm candidates for novel nanoelectronic devices and a fruitful playground for fundamental physics. Ultra-thin nanowires, with diameters below 10 nm, present exotic quantum effects due to the confinement of the wave functions, e.g. widening of the electronic band-gap, deepening of the dopant states. However, although several reports of sub-10 nm wires exist to date, the most common NWs have diameters that range from 20 to 200 nm, where these quantum effects are absent or play a very minor role. Yet, the research activity on this field is very intense and these materials still promise to provide an important paradigm shift for the design of emerging electronic devices and different kinds of applications. A legitimate question is then: what makes a nanowire different from bulk systems? The answer is certainly the large surface-to-volume ratio. In this article we discuss the most salient features of surface physics and chemistry in group-IV semiconducting nanowires, focusing mostly on Si NWs. First we review the state-of-the-art of NW growth to achieve a smooth and controlled surface morphology. Next we discuss the importance of a proper surface passivation and its role on the NW electronic properties. Finally, stressing the importance of a large surface-to-volume ratio and emphasizing the fact that in a NW the surface is where most of the action takes place, we discuss molecular sensing and molecular doping.

  18. Plausible surface models for Titan

    NASA Technical Reports Server (NTRS)

    Lunine, Jonathan I.

    1992-01-01

    Current understanding of the nature of Titan's surface and some new ideas for explaining the curious radar returns from Saturn's largest satellite are reviewed. Pre-Voyager models of the surface, based largely on cosmochemistry and the discovery of atmospheric methane, allowed for a range of possibilities, including pure methane oceans. The Voyager 1 flyby ruled out this last possibility, replacing it with compelling observational arguments in favor of a mixed light hydrocarbon and nitrogen ocean. Ground based radar observations indicated a surprisingly reflective surface which is inconsistent with a hydrocarbon ocean and more reminiscent of the Galilean Satellites. Nonetheless, passive radiometric measurements of the surface do not support the notion that Titan's surface is like that of the Galilean satellites. One of the arguments against hydrocarbon oceans reflecting radar energy is that most solid, complex hydrocarbon and nitriles will be denser than the liquid and sink. Nonetheless, many of the aerosol species will coagulate in highly nonspherical patterns, and some species probably polymerize in long chains. Such chains will have very low sedimendation velocities in the ocean and may remain near the surface through ocean mixing process. The prospect of an oceanic 'soup' of polar polymers acting as volume reflectors at radio wevelengths suggests that the interpretation of radar observations needs evaluation.

  19. Polymers at Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    Tsige, Mesfin

    2015-03-01

    Interfaces between solids, liquids, and gases play an important role in a wide range of practical applications and have been a subject of scientific interest since Poisson showed in 1831 that the order parameter of liquids near interfaces must deviate considerably from its bulk value. In particular, polymers at surfaces and interfaces have been a subject of extensive theoretical, experimental and computational studies for a long time due to their use in many diverse applications ranging from antifouling coatings to flexible electronic devices. Understanding the structure and thermodynamic properties of polymers at surfaces and interfaces is thus an area of fundamental and current technological interest. Although encouraging experimental progress has been made over the years in understanding the molecular structure of polymers in contact with various environments, selectively probing their structure and dynamics at surfaces and interfaces has been extremely difficult. Computer simulations, especially molecular dynamics (MD) simulations, have proven over the years to be an invaluable tool in providing molecular details at interfaces that are usually lacking in the experimental data. In this talk, I'll give an overview of some previous simulation efforts to understand the structure and dynamics of polymers at surfaces and buried interfaces. I will conclude by presenting our current and ongoing work on combining ab initio calculations and MD simulations with Sum Frequency Generation (SFG) Spectroscopy to study polymer surfaces. This approach demonstrates the future role of MD in surface science. Work supported by NSF (DMR0847580 and DMR1410290) and Petroleum Research Fund of the American Chemical Society.

  20. Photochemistry on rough metal surfaces

    SciTech Connect

    Goncher, G.M.; Parsons, C.A.; Harris, C.B.

    1984-09-13

    The general question of laser-induced photochemistry on metal surfaces is addressed. Specifically, the authors have studied resonant photodecomposition of a variety of aromatic molecules on roughened silver surfaces in ultrahigh vacuum. A continuous ion laser source at a number of different wavelengths in the region 350-410 nm was used to produce graphitic carbon on the surface which was monitored by Raman spectroscopy at the 1580-cm/sup -1/ band of surface carbon. Laser power-dependence studies of fragmentation rate for several molecules at 406.7nm indicate that the initial absorption step is a two-photon process. Energetic considerations imply that photochemistry for other molecules studied is also due to multiphoton absorption, except for benzaldehyde fragmentation at 350.7-nm excitation, where the photodecomposition rate is linear. Distance-dependence studies of photofragmentation rates by use of an inert spacer layer to separatte the molecule undergoing photochemistry from the surface indicate that energy transfer to the metal surface is important in determining the reaction rate. Decomposition mechanism has not been fully evaluated.