Sample records for bracket base surface

  1. Effect of different surface treatments for ceramic bracket base on bond strength of rebonded brackets.

    PubMed

    Guarita, Monique Kruger; Moresca, Alexa Helena Köhler; Losso, Estela Maris; Moro, Alexandre; Moresca, Ricardo Cesar; Correr, Gisele Maria

    2015-01-01

    The aim of this study was to evaluate the shear bond strength of rebonded ceramic brackets after subjecting the bracket base to different treatments. Seventy-five premolars were selected and randomly distributed into five groups (n=15), according to the type of the bracket surface treatment: I, no treatment, first bonding (control); II, sandblasting with aluminum oxide; III, sandblasting + silane; IV, silica coating + silane; and V, silicatization performed in a laboratory (Rocatec system). The brackets were fixed on an enamel surface with Transbond XT resin without acid etching. The brackets were then removed and their bases were subjected to different treatments. Thereafter, the brackets were fixed again to the enamel surface and the specimens were subjected to shear bond strength (SBS) test. The adhesive remnant index (ARI) was then evaluated for each specimen. Data were subjected to ANOVA and Tukey's tests (?=0.05). A statistically significant difference was observed only between Rocatec and the other groups; the Rocatec group showed the lowest SBS values. The highest SBS values were observed for group 1, without any significant difference from the values for groups II, III and IV. Most groups had a higher percentage of failures at the enamel-resin interface (score 1). It was concluded that the surface treatments of rebonded ceramic brackets were effective, with SBS values similar to that of the control group, except Rocatec group. PMID:25672386

  2. Improvements in bracket base design.

    PubMed

    Smith, D C; Maijer, R

    1983-04-01

    Acid etch bonding of orthodontic attachments to the labial and lingual surfaces of teeth is generally adequate for clinical service. Failures do occur, and these are related to technique problems in acid etching or resin manipulation or to bracket base design. The widely used foil mesh base can present problems in retention because of design defects or corrosion. Improvement in mechanical retention of resin to the attachment base would result in significant improvements in bonding and fewer clinical failures. One of our approaches to improved retention is to fuse metallic or ceramic particles onto the bracket base so as to achieve a particulate or porous layer into which resin can penetrate. The results of bond-strength tests showed that a 100 percent increase in bond strength could be obtained with sintered porous metal-coated brackets. Further development is proceeding. PMID:6340515

  3. A quantitative AFM analysis of nano-scale surface roughness in various orthodontic brackets.

    PubMed

    Lee, Gi-Ja; Park, Ki-Ho; Park, Young-Guk; Park, Hun-Kuk

    2010-10-01

    In orthodontics, the surface roughnesses of orthodontic archwire and brackets affect the effectiveness of arch-guided tooth movement, corrosion behavior, and the aesthetics of orthodontic components. Atomic force microscopy (AFM) measurements were used to provide quantitative information on the surface roughness of the orthodontic material. In this study, the changes in surface roughness of various orthodontic bracket slots before and after sliding movement of archwire in vitro and in vivo were observed through the utilization of AFM. Firstly, we characterized the surface of four types of brackets slots as follows: conventional stainless steel (Succes), conventional ceramic (Perfect), self-ligating stainless steel (Damon) and self-ligating ceramic (Clippy-C) brackets. Succes) and Damon brackets showed relatively smooth surfaces, while Perfect had the roughest surface among the four types of brackets used. Secondly, after in vitro sliding test with beta titanium wire in two conventional brackets (Succes and Perfect), there were significant increases in only stainless steel bracket, Succes. Thirdly, after clinical orthodontic treatment for a maximum of 2 years, the self-ligating stainless steel bracket, Damon, showed a significant increase in surface roughness. But self-ligating ceramic brackets, Clippy-C, represented less significant changes in roughness parameters than self-ligating stainless steel ones. Based on the results of the AFM measurements, it is suggested that the self-ligating ceramic bracket has great possibility to exhibit less friction and better biocompatibility than the other tested brackets. This implies that these bracket slots will aid in the effectiveness of arch-guided tooth movement. PMID:20646928

  4. Comparison surface characteristics and chemical composition of conventional metallic and nickel-free brackets.

    PubMed

    Shintcovsk, Ricardo Lima; Knop, Luegya Amorim Henriques; Gandini, Luiz Gonzaga; Martins, Lidia Parsekian; Pires, Aline Segatto

    2015-01-01

    This study aims at comparing conventional and nickel-free metal bracket surface characteristics with elemental composition by scanning electron microscopy (SEM), using energy dispersive spectroscopy (EDS). The sample consisted of 40 lower incisor brackets divided into four groups: ABZ = conventional brackets, Kirium Abzil 3M® (n = 10); RL = conventional brackets, Roth Light Morelli® (n = 10); NF = nickel-free brackets, Nickel-Free Morelli® (n = 10); and RM = nickel-free brackets, Roth Max Morelli® (n = 10). Qualitative evaluation of the bracket surface was performed using SEM, whereby surface features were described and compared. The elemental composition was analyzed by EDS. According to surface analysis, groups ABZ and RL showed a homogeneous surface, with better finishing, whereas the surfaces in groups NF and RM were rougher. The chemical components with the highest percentage were Fe, Cr and C. Groups NF and MR showed no nickel in their composition. In conclusion, the bracket surface of the ABZ and RL groups was more homogeneous, with grooves and pores, whereas the surfaces in groups NF and RM showed numerous flaws, cracks, pores and grooves. The chemical composition analysis confirmed that the nickel-free brackets had no Ni in their composition, as confirmed by the manufacturer's specifications, and were therefore safe to use in patients with a medical history of allergy to this metal. PMID:25590508

  5. A quantitative AFM analysis of nano-scale surface roughness in various orthodontic brackets

    Microsoft Academic Search

    Gi-Ja Lee; Ki-Ho Park; Young-Guk Park; Hun-Kuk Park

    2010-01-01

    In orthodontics, the surface roughnesses of orthodontic archwire and brackets affect the effectiveness of arch-guided tooth movement, corrosion behavior, and the aesthetics of orthodontic components. Atomic force microscopy (AFM) measurements were used to provide quantitative information on the surface roughness of the orthodontic material. In this study, the changes in surface roughness of various orthodontic bracket slots before and after

  6. Finite element study on modification of bracket base and its effects on bond strength

    PubMed Central

    Shyagali, Tarulatha R.; Bhayya, Deepak P.; Urs, Chandralekha B.; Subramaniam, Shashikala

    2015-01-01

    OBJECTIVE: This article aims to analyze the difference in stresses generated in the bracket-cement-tooth system by means of a peel load in single and double-mesh bracket bases using a three-dimensional finite element computer model. MATERIAL AND METHODS: A three-dimensional finite element model of the bracket-cement-tooth system was constructed and consisted of 40,536 bonds and 49,201 finite elements using a commercial mesh generating programmer (ANSYS 7.0). Both single and double-mesh bracket bases were modified by varying the diameter from 100-400 µm progressively, and the spacing between the mesh wires was kept at 300 µm for each diameter of wire. A peel load was applied on the model to study the stresses generated in different layers. RESULTS: In case of double-mesh bracket base, there was reduction in stress generation at the enamel in comparison to single-mesh bracket base. There was no difference in stress generated at the bracket layer between single and double-mesh bracket bases. At the impregnated wire mesh (IWM), layer stresses increased as the wire diameter of the mesh increased. CONCLUSION: Results show that bracket design modification can improve bonding abilities and simultaneously reduce enamel damage while debonding. These facts may be used in bringing about the new innovative bracket designs for clinical use. PMID:25992991

  7. Heat treatment following surface silanization in rebonded tribochemical silica-coated ceramic brackets: shear bond strength analysis

    PubMed Central

    SILVA, Emilia Adriane; TRINDADE, Flávia Zardo; RESKALLA, Hélcio Nagib José Feres; de QUEIROZ, José Renato Cavalcanti

    2013-01-01

    Objective This study aimed to evaluate the effects of heat treatment on the tribochemical silica coating and silane surface conditioning and the bond strength of rebonded alumina monocrystalline brackets. Material and Methods Sixty alumina monocrystalline brackets were randomly divided according to adhesive base surface treatments (n=20): Gc, no treatment (control); Gt, tribochemical silica coating + silane application; Gh, as per Gt + post-heat treatment (air flux at 100ºC for 60 s). Brackets were bonded to the enamel premolars surface with a light-polymerized resin and stored in distilled water at 37ºC for 100 days. Additionally, half the specimens of each group were thermocycled (6,000 cycles between 5-55ºC) (TC). The specimens were submitted to the shear bond strength (SBS) test using a universal testing machine (1 mm/min). Failure mode was assessed using optical and scanning electron microscopy (SEM), together with the surface roughness (Ra) of the resin cement in the bracket using interference microscopy (IM). 2-way ANOVA and the Tukey test were used to compare the data (p>0.05). Results The strategies used to treat the bracket surface had an effect on the SBS results (p=0.0), but thermocycling did not (p=0.6974). Considering the SBS results (MPa), Gh-TC and Gc showed the highest values (27.59±6.4 and 27.18±2.9) and Gt-TC showed the lowest (8.45±6.7). For the Ra parameter, ANOVA revealed that the aging method had an effect (p=0.0157) but the surface treatments did not (p=0.458). For the thermocycled and non-thermocycled groups, Ra (µm) was 0.69±0.16 and 1.12±0.52, respectively. The most frequent failure mode exhibited was mixed failure involving the enamel-resin-bracket interfaces. Conclusion Regardless of the aging method, Gh promoted similar SBS results to Gc, suggesting that rebonded ceramic brackets are a more effective strategy. PMID:24037072

  8. Shear bond resistance and enamel surface comparison after the bonding and debonding of ceramic and metallic brackets

    PubMed Central

    da Rocha, José Maurício; Gravina, Marco Abdo; Campos, Marcio José da Silva; Quintão, Cátia Cardoso Abdo; Elias, Carlos Nelson; Vitral, Robert Willer Farinazzo

    2014-01-01

    Objective To evaluate, in vitro, the shear bond strength presented by three brands of polycrystalline ceramic brackets and one brand of metallic bracket; verify the adhesive remnant index (ARI) after the tests, and analyze, through scanning electron microscopy (SEM) the enamel surface topography after debonding, detecting the release of mineral particles. Methods Sixty bovine lower incisors were used. Three ceramic brackets (Allure®, InVu®, and Clarity®) and one metallic bracket (Geneus®) were bonded with Transbond XT®. Kruskal-Wallis's test (significance level set at 5%) was applied to the results of share bond and ARI. Mann Whitney's test was performed to compare the pairs of brackets in relation to their ARI. Brown-Forsythe's test (significance level set at 5%) was applied to the results of enamel chemical composition. Comparisons between groups were made with Games-Howell's and the Post-hoc tests. Results No statistically significant difference was observed in relation to the shear bond strength loads. Clarity® brackets were the most affected in relation to the surface topography and to the release of mineral particles of enamel (calcium ions). Conclusion With regard to the ARI, there was a prevalence of score 4 (40.4%). As for enamel surface topography, the Geneus® bracket was the only one which did not show superficial tissue loss. The InVu® and Clarity® ones showed cohesive fractures in 33.3% and the Allure® in 50%, the latter being the one that presented most fractures during removal. PMID:24713563

  9. Influence of various surface-conditioning methods on the bond strength of metal brackets to ceramic surfaces.

    PubMed

    Schmage, Petra; Nergiz, Ibrahim; Herrmann, Wolfram; Ozcan, Mutlu

    2003-05-01

    With the increase in adult orthodontic treatment comes the need to find a reliable method for bonding orthodontic brackets onto metal or ceramic crowns and fixed partial dentures. In this study, shear bond strength and surface roughness tests were used to examine the effect of 4 different surface conditioning methods: fine diamond bur, sandblasting, 5% hydrofluoric acid, and silica coating for bonding metal brackets to ceramic surfaces of feldspathic porcelain. Sandblasting and hydrofluoric acid were further tested after silane application. A total of 120 ceramic disc samples were produced, and 50 were used for surface roughness measurements. The glazed ceramic surfaces were used as controls. Metal brackets were bonded to the ceramic substrates with a self-curing composite. The samples were stored in 0.9% NaCl solution for 24 hours and then thermocycled (5000 times, 5 degrees C to 55 degrees C, 30 seconds). Shear bond tests were performed with a universal testing device, and the results were statistically analyzed. Chemical surface conditioning with either hydrofluoric acid (4.3 microm) or silicatization (4.4 microm) resulted in significantly lower surface roughness than mechanical conditioning (9.3 microm, diamond bur; 9.7 microm, sandblasting) (P <.001). The surface roughness values reflect the mean peak-and-valley distances. The bond strengths of the brackets bonded to the ceramic surfaces treated by hydrofluoric acid with and without silane (12.2 and 14.7 MPa, respectively), silicatization (14.9 MPa), and sandblasting with silane (15.8 MPa) were significantly higher (P <.001) than those treated by mechanical roughening with fine diamond burs (1.6 MPa) or sandblasting (2.8 MPa). The highest bond strength values were obtained with sandblasting and silicatization with silane or hydrofluoric acid without silane; these fulfilled the required threshold. The use of silane after hydrofluoric acid etching did not increase the bond strength. Diamond roughening and sandblasting showed the highest surface roughness; they can damage the ceramic surface. Acid etching gave acceptable results for clinical use, but the health risks should be considered. The silicatization technique has the potential to replace the other methods; yet cohesive failures were observed in the ceramic during removal of the brackets. PMID:12750673

  10. Enamel surface evaluation after bracket debonding and different resin removal methods

    PubMed Central

    Vidor, Michele Machado; Felix, Rafael Perdomo; Marchioro, Ernani Menezes; Hahn, Luciane

    2015-01-01

    OBJECTIVE: To assess enamel surface under scanning electron microscopy (SEM) after resin removal and enamel polishing procedures following brackets debonding, as well as compare the time required for these procedures. METHODS: A total of 180 deciduous bovine incisors were used. The enamel surface of each tooth was prepared and brackets were bonded with light cured Transbond XT composite resin. Brackets were removed in a testing machine. The samples were randomized and equally distributed into nine groups according to the resin removal and polishing technique: Group 1, 30-blade tungsten carbide bur in high speed; Group 2, 30-blade tungsten carbide bur in high speed followed by a sequence of 4 Sof-lex polishing discs (3M); Group 3, 30-blade tungsten carbide bur in high speed followed by Enhance tips (Dentsply). All groups were subdivided into (a) unpolished; (b) polished with aluminum oxide paste; and (c) polished with water slurry of fine pumice. Subsequently, the enamel surface was assessed and statistical analysis was carried out. RESULTS: There were statistically significant differences in enamel roughness and removal time among all groups. Groups 3a, 3b and 3c appeared to be the most efficient methods of removing resin with low damages to enamel. Groups 2a, 2b and 2c were the most time consuming procedures, and Group 2a caused more damages to enamel. CONCLUSION: The suggested protocol for resin removal is the 30-blade tungsten carbide bur in high speed followed by Enhance tips and polishing with aluminum oxide paste. This procedure seems to produce less damages and is less time consuming. PMID:25992989

  11. Effect of alloy type and surface conditioning on roughness and bond strength of metal brackets.

    PubMed

    Nergiz, Ibrahim; Schmage, Petra; Herrmann, Wolfram; Ozcan, Mutlu

    2004-01-01

    The effect of 5 different surface conditioning methods on bonding of metal brackets to cast dental alloys was examined. The surface conditioning methods were fine (30-microm) or rough (125-microm) diamond bur, sandblasting (50-microm or 110-microm aluminum oxide [Al2O3]), and silica coating (30-microm silica). Fifty disc-shaped specimens of 5 different alloys (gold-silver, palladium-silver, nickel-chromium, cobalt-chromium, and titanium) were ground with 1200-grit silicone carbide abrasive and polished before being reused for each conditioning method. Polished surfaces were used as negative controls. After measuring surface roughness (RZ), metal brackets were bonded to the conditioned alloys with a self-curing resin composite. Specimens were thermocycled (5000 times, 5 degrees-55 degrees C, 30 seconds), and shear bond tests were performed. Significantly higher (P<.001) surface roughnesses were observed with use of the rough diamond bur (RZ approximately 33 microm), 110-microm Al2O3 (RZ approximately 14 microm), and fine diamond bur (RZ approximately 10 microm), compared with the controls (RZ approximately 1 microm). Silica coating (RZ approximately 4 microm) and 50-microm Al2O3 (RZ approximately 4 microm) demonstrated no significant difference (P>.001) in roughness when compared with the controls. The control group showed no resistance to shear forces (0 MPa). Bond values were greater (19 MPa) when silica coating was used, compared with 50-microm Al2O3 (7 MPa) and 110-microm Al2O3 (8 MPa) for all alloys tested. However, interaction between alloys and conditioning methods exhibited significant differences (P<.0001). PMID:14718878

  12. Effect of chlorhexidine-containing prophylactic agent on the surface characterization and frictional resistance between orthodontic brackets and archwires: an in vitro study

    PubMed Central

    2013-01-01

    Background The purpose of this study was to assess the surface characterization and frictional resistance between stainless steel brackets and two types of orthodontic wires made of stainless steel and nickel-titanium alloys after immersion in a chlorhexidine-containing prophylactic agent. Methods Stainless steel orthodontic brackets with either stainless steel (SS) or heat-activated nickel-titanium (Ni-Ti) wires were immersed in a 0.2% chlorhexidine and an artificial saliva environment for 1.5 h. The frictional force was measured on a universal testing machine with a crosshead speed of 10 mm/min over a 5-mm of archwire. The surface morphology of bracket slots and surface roughness of archwires after immersion in chlorhexidine were also characterized using a scanning electron microscope (SEM) and an atomic force microscope (AFM), respectively. Results There was no significant difference in the frictional resistance values between SS and Ni-Ti wires immersed in either chlorhexidine or artificial saliva. The frictional resistance values for the SS and Ni-Ti wires immersed in 0.2% chlorhexidine solution were not significantly different from that inartificial saliva. No significant difference in the average surface roughness for both wires before (as-received) and after immersion in either chlorhexidine or artificial saliva was observed. Conclusions One-and-half-hour immersion in 0.2% chlorhexidine mouthrinse did not have significant influence on the archwires surface roughness or the frictional resistance between stainless steel orthodontic brackets and archwires made of SS and Ni-Ti. Based on these results, chlorhexidine-containing mouthrinses may be prescribed as non-destructive prophylactic agents on materials evaluated in the present study for orthodontic patients. PMID:24325758

  13. Tiedown Bracket

    NASA Technical Reports Server (NTRS)

    Mashburn, D.; Wald, J. E.; Helmsin, F. K.

    1982-01-01

    Tiedown bracket secured to concrete slab with lag anchor and lag bolt. A trailer or other heavy equipment can be anchored by tethering it to strapping bolt. When bracket is no longer needed, it can be removed, leaving behind only lag anchor. Bracket is easily installed and removed without damage to concrete slab.

  14. Frictional and mechanical properties of diamond-like carbon-coated orthodontic brackets.

    PubMed

    Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Nakagaki, Susumu; Endo, Kazuhiko; Mizoguchi, Itaru

    2013-04-01

    This study investigated the effects of a diamond-like carbon (DLC) coating on frictional and mechanical properties of orthodontic brackets. DLC films were deposited on stainless steel brackets using the plasma-based ion implantation/deposition (PBIID) method under two different atmospheric conditions. As-received metal brackets served as the control. Two sizes of stainless steel archwires, 0.018 inch diameter and 0.017 × 0.025 inch cross-section dimensions, were used for measuring static and kinetic friction by drawing the archwires through the bracket slots, using a mechanical testing machine (n = 10). The DLC-coated brackets were observed with a scanning electron microscope (SEM). Values of hardness and elastic modulus were obtained by nanoindentation testing (n = 10). Friction forces were compared by one-way analysis of variance and the Scheffé test. The hardness and elastic modulus of the brackets were compared using Kruskal-Wallis and Mann-Whitney U-tests. SEM photomicrographs showed DLC layers on the bracket surfaces with thickness of approximately 5-7 ?m. DLC-coated brackets deposited under condition 2 showed significantly less static frictional force for the stainless steel wire with 0.017 × 0.025 inch cross-section dimensions than as-received brackets and DLC-coated brackets deposited under condition 1, although both DLC-coated brackets showed significantly less kinetic frictional force than as-received brackets. The hardness of the DLC layers was much higher than that of the as-received bracket surfaces. In conclusion, the surfaces of metal brackets can be successfully modified by the PBIID method to create a DLC layer, and the DLC-coating process significantly reduces frictional forces. PMID:21934113

  15. Microleakage and shear bond strength of orthodontc brackets bonded to hypomineralized enamel following different surface preparations

    PubMed Central

    Shahabi, Mostafa; Mohamadipour, Hamideh; Moosavi, Horieh

    2014-01-01

    Objectives: This study investigated the effects of several conditioning methods on shear bond strength (SBS) and microleakage of orthodontic brackets bonded to demineralized enamel. Study Design: One hundred premolars were selected and immersed in a cariogenic solution for 12 weeks. The teeth were randomly assigned into 5 groups. In groups 1 and 2, the teeth underwent acid etching for 30 and 120 seconds, respectively. In group 3, a combination of laser and acid etching was employed. A self-etch primer (SEP) was applied in group 4 and in group 5, the teeth were exposed to acidulated phosphate fluoride (APF) for 4 minutes before etching. After bracket bonding, the teeth were immersed in methylen blue for 12 hours and then were mounted in acrylic resin. SBS was determined with an Instron Universal Testing Machine and the amount of microleakage under the brackets was assessed under a stereomicroscope. Results: The lowest SBS was related to the SEP group and the highest one was observed in the specimens prepared by APF+acid etching. There was a significant difference in SBS (p=0.009), but not in microleakage (p=0.971) of the study groups. The SBS of the specimens treated with SEP was significantly Lower than the other groups, which were not significantly different from each other. The SEP group displayed a higher frequency of bond failure at the enamel-adhesive interface. Conclusions: Enamel preparation with SEP provided the lowest SBS among the groups. All groups showed some degree of microleakage. There was no significant correlation between SBS and microleakage. Key words:Bond strength, microleakage, bonding, self-etch primer, Er:YAG laser. PMID:24790708

  16. Different corrosive effects on hydroxyapatite nanocrystals and amine fluoride-based mouthwashes on dental titanium brackets: a comparative in vitro study.

    PubMed

    Lelli, Marco; Marchisio, Olivia; Foltran, Ismaela; Genovesi, Annamaria; Montebugnoli, Giulia; Marcaccio, Massimo; Covani, Ugo; Roveri, Norberto

    2013-01-01

    Titanium plates treated in vitro with a mouthwash containing amine fluoride (100 ppm F-) and another containing zinc-substituted carbonate-hydroxyapatite have been analyzed by scanning electron microscopy and atomic force microscopy to evaluate the modification of the surface roughness induced by treatment with these two different mouthwashes. The treatment with F--based mouthwash produces a roughness characterized by higher peaks and deeper valleys in the streaks on the titanium bracket surface compared with those observed in the reference polished titanium plates. This effect causes a mechanical weakness in the metallic dental implant causing bacterial growth and therefore promotes infection and prosthesis contamination. However, the in vitro treatment with a mouthwash containing zinc-substituted carbonate-hydroxyapatite reduced the surface roughness by filling the streaks with an apatitic phase. This treatment counteracts the surface oxidative process that can affect the mechanical behavior of the titanium dental implant, which inhibits the bacterial growth contaminating prostheses. PMID:23355777

  17. Effect of surface treatment with sandblasting and Er,Cr:YSGG laser on bonding of stainless steel orthodontic brackets to silver amalgam

    PubMed Central

    Kachoei, Mojgan; Rikhtegaran, Sahand; Fathalizadeh, Farzaneh; Navimipour, Elmira J.

    2012-01-01

    Objectives: Satisfactory bonding of orthodontic attachments to amalgam is a challenge for orthodontists. The aim of this in vitro study was to compare the shear bond strength of stainless steel orthodontic brackets to silver amalgam treated with sandblasting and Er,Cr:YSGG laser. Study Design: Fifty-four amalgam discs were prepared, polished and divided into three groups: In group 1 (the control group) the premolar brackets were bonded using Panavia F resin cement without any surface treatment; in groups 2 and 3, the specimens were subjected to sandblasting and Er,Cr:YSGG laser respectively, before bracket bonding. After immersing in distilled water at 37°C for 24 hours, all the specimens were tested for shear bond strength. Bond failure sites were evaluated under a stereomicroscope. Data was analyzed using one-way ANOVA and a post hoc Tukey test. Results: The highest and lowest shear bond strength values were recorded in the laser and control groups, respectively. There were significant differences in mean shear bond strength values between the laser and the other two groups (p<0.05). However, there were no significant differences between the sandblast and control groups (p=0.5). Conclusions: Amalgam surface treatment with Er,Cr:YSGG laser increased shear bond strength of stainless steel orthodontic brackets. Key words: Amalgam, surface treatment, shear bond strength, sandblasting, Er,Cr:YSGG laser. PMID:22143706

  18. A comparative study of frictional force in self-ligating brackets according to the bracket-archwire angulation, bracket material, and wire type

    PubMed Central

    Lee, Souk Min

    2015-01-01

    Objective This study aimed to compare the frictional force (FR) in self-ligating brackets among different bracket-archwire angles, bracket materials, and archwire types. Methods Passive and active metal self-ligating brackets and active ceramic self-ligating brackets were included as experimental groups, while conventional twin metal brackets served as a control group. All brackets were maxillary premolar brackets with 0.022 inch [in] slots and a -7° torque. The orthodontic wires used included 0.018 round and 0.019 × 0.025 in rectangular stainless steel wires. The FR was measured at 0°, 5°, and 10° angulations as the wire was drawn through the bracket slots after attaching brackets from each group to the universal testing machine. Static and kinetic FRs were also measured. Results The passive self-ligating brackets generated a lower FR than all the other brackets. Static and kinetic FRs generally increased with an increase in the bracket-archwire angulation, and the rectangular wire caused significantly higher static and kinetic FRs than the round wire (p < 0.001). The metal passive self-ligating brackets exhibited the lowest static FR at the 0° angulation and a lower increase in static and kinetic FRs with an increase in bracket-archwire angulation than the other brackets, while the conventional twin brackets showed a greater increase than all three experimental brackets. Conclusions The passive self-ligating brackets showed the lowest FR in this study. Self-ligating brackets can generate varying FRs in vitro according to the wire size, surface characteristics, and bracket-archwire angulation. PMID:25667913

  19. Colour and translucency of tooth-coloured orthodontic brackets

    Microsoft Academic Search

    Yong-Keun Lee

    SUMMARY The objective of this study was to determine the refl ected and transmitted colours and the diffuse light transmittance of tooth-coloured brackets. Four ceramic and four plastic brands were evaluated and fi ve brackets of each brand were tested. Refl ected colour and spectral refl ectance of the labial surface of the brackets were measured according to the Commission

  20. The effect of surface treatment with Er: YAG laser on shear bond strength of orthodontic brackets to fiber-reinforced composite

    PubMed Central

    Dehghani, Mahboobe

    2014-01-01

    Objectives: This study aimed to investigate the effect of surface treatment with Er:YAG laser on shear bond strength (SBS) of orthodontic brackets to fiber-reinforced composite (FRC). Study Design: Ninety human premolars were randomly divided into six groups of 15. FRC bars were bonded to the teeth with a flowable composite (FC) and then underwent following treatments. In group 1 no further treatment was performed. In group 2 the FRC surfaces were covered by FC. An Er:YAG laser was employed to treat FRCs in groups 3 ( 200 mJ/10 Hz) and 4 (300 mJ/15 Hz). The FRC strips in groups 5 and 6 were first covered by FC and then irradiated with Er:YAG laser at 200 mJ/10 Hz (group 5) or 300 mJ/15 Hz (group 6). Stainless steel brackets were bonded to FRCs using a light-cure adhesive system. After 24 hours, the samples were tested for SBS and the adhesive remnant index (ARI) scores were determined. Results: There was a significant difference in SBS among the study groups (P <0.001). Pairwise comparisons indicated that SBS was significantly lower in group 1 compared to all other groups (p<0.05) except group 2. Bond strength in group 6 was significantly greater than all the study groups (p<0.05) except group 5. No significant difference was found in ARI scores among the groups. Conclusions: Covering the FRC surface by a layer of flowable composite and then application of Er:YAG laser at 300 mJ/15 Hz could be recommended to increase bond strength of orthodontic attachments to FRC. Key words:Fiber-reinforced composite, orthodontics, Sshear bond strength, laser, Er:YAG, surface treatment, bracket, FRC. PMID:25593660

  1. Shingle assembly with support bracket

    DOEpatents

    Almy, Charles

    2007-01-02

    A shingle system, mountable to a support surface, includes overlapping shingle assemblies. Each shingle assembly comprises a support bracket, having upper and lower ends, secured to a shingle body. The upper end has an upper support portion, extending away from the shingle body, and an upper support-surface-engaging part, engageable with a support surface so that the upper edge of the shingle body is positionable at a first distance from the support surface to create a first gap therebetween. The lower end has a lower support portion extending away from the lower surface. The support brackets create: (1) a second gap between shingle bodies of the first and second shingle assemblies, and (2) an open region beneath the first shingle assembly fluidly coupling the first and second gaps.

  2. The Effect of an Acidic Food-Simulating Environment on the Shear Bond Strength of Self-Ligating Brackets with Different Base Designs

    PubMed Central

    Sheibaninia, Ahmad; Sepasi, Sepehr; Saghiri, Mohammad Ali; Sepasi, Setareh

    2014-01-01

    Aim. This study aims to evaluate the effect of acidic food simulant and (acetic acid 3%) on the shear bond strength (SBS) and adhesive remnant index (ARI) scores of one conventional and three different self-ligating brackets with different base designs. Materials and Methods. Freshly extracted first maxillary premolars (n = 160) were embedded in resin blocks. A conventional stainless steel bracket, Equilibrium 2, and three types of self-ligating brackets, Speed, In-Ovation R, and Damon 3MX, were bonded to teeth and exposed to distilled water (groups 1, 3, 5, and 7) or acetic acid 3% (groups 2, 4, 6, 8) for 12 weeks. SBS and ARI were calculated and statistical analysis was performed with the analysis of variance (SBS) or ?2 test (ARI) to compare values between the different groups. Results. Equilibrium 2 and In-Ovation R showed a significantly lower SBS in the acidic environment than in distilled water. Significant differences in ARI scores were found for Equilibrium 2 after immersion in an acidic environment, shifting from 0 in distilled water to 2 in an acidic environment. Conclusions. Equilibrium 2 and In-Ovation R brackets showed a significant decrease in SBS after a 12-week immersion in acetic acid 3%, although all groups showed clinically acceptable SBS. Equilibrium 2 showed significant differences in ARI scores when exposed to acetic acid 3%. PMID:25328524

  3. An in Vitro Evaluation of Remineralization Potential of Novamin® on Artificial Enamel Sub-Surface Lesions Around Orthodontic Brackets Using Energy Dispersive X-Ray Analysis (EDX)

    PubMed Central

    Padmanabhan, Sridevi; Chitharanjan, Arun B

    2014-01-01

    Objective: To evaluate and compare the Ca/P ratio of enamel samples around the orthodontic brackets for time periods of 0, 2 and 10 days in two groups (control group and study group). Materials and Methods: Forty extracted teeth were randomly divided into control group and study group. All samples were demineralized and incubated in artificial saliva at 37°C for a period of 10 days after demineralization. During this phase the enamel samples in the study group were treated with remineralizing paste (NuproNusolution containing Novamin®-Dentsply) for 10 days. At the end of the incubation period, Ca/P ratios were analyzed for both the groupsby EDX analysis. Data obtained was subjected to statistical analysis using student t-test for paired samples and Student t- test for individual samples (p ? 0.05). Results: It was found that the mean Ca/P ratio was significantly lower for the control group as compared to the study group (p-value < 0.05) after 10 d of incubation. Conclusion: Novamin® containing remineralization toothpaste showed significant remineralizing potential in inhibition of artificial enamel sub-surface lesion around bracket after 10 days of remineralization phase. EDX element analysis was found to be an efficient method to quantify the changes in mineral content of a sample during in vitro caries studies. PMID:25584326

  4. Comparison of the frictional resistance between archwire and different bracket system: An in vitro study

    PubMed Central

    Pillai, Ajith R.; Gangadharan, Anil; Kumar, Satheesh; Shah, Anwar

    2014-01-01

    Background and Objectives: The purpose of this study is to evaluate the frictional resistance generated by conventional stainless steel, radiance ceramic bracket, self-ligating and composite brackets using a 0.019 × 0.025 stainless steel straight length wires in a 022 slot and to select brackets based on their frictional characteristic. Methodology: In order to conduct this study, four different types of bracket system were selected of the mclaughlin-bennet-trevesi (MBT) discipline. They are Group 1 - stainless steel, Group 2 - composite bracket Group 3 - (American Orthodontics) radiance ceramic bracket Group 4 - self-ligating bracket (SLB) (Empower). In this study, five maxillary brackets of an arch of each type were used. All brackets are 0.022 × 0.028 in preadjusted edgewise appliance which simulates the dental arch. Five brackets were bonded to a stainless steel bar of dimension 150 mm × 25 mm × 3 mm. The bracket-arch wire units were submitted to mechanical test with an Instron universal testing machine 3365. A testing apparatus or holding jig was designed to hold the bracket during the mechanical test. Each sample was pulled at a speed of 6 mm for 1 min. Descriptive statistical information including mean and standard deviation of maximum friction force was calculated for each bracket wire combination. Interpretation and Conclusion: The SLB has the least friction among the four groups. The ceramic bracket showed the highest friction followed by stainless steel bracket, composite bracket, and SLB. PMID:25210359

  5. Colour and translucency of tooth-coloured orthodontic brackets.

    PubMed

    Lee, Yong-Keun

    2008-04-01

    The objective of this study was to determine the reflected and transmitted colours and the diffuse light transmittance of tooth-coloured brackets. Four ceramic and four plastic brands were evaluated and five brackets of each brand were tested. Reflected colour and spectral reflectance of the labial surface of the brackets were measured according to the Commission Internationale de l'Eclairage (CIE) colour scale and transmitted colour and diffuse spectral transmittance measured with a spectrophotometer. One-way analyses of variance were performed for the reflected and transmitted colour co-ordinates (CIE L*, a*, and b*) and for light transmittance according to bracket brand. The range for CIE L* (lightness) was 36.2-50.3, for a* (red-green parameter) -1.3-3.8 and for b* (yellow-blue parameter) -2.9-11.2. All these colour co-ordinates were influenced by bracket brand (P < 0.05). Diffuse light transmittance was also influenced by bracket brand and ranged from 44.9 to 75.9 per cent (P < 0.05). Colour and transmittance varied by bracket brand. Variations in optical properties influenced the aesthetic performance of the brackets and the degree of cure of the adhesive that is possible through the brackets. Further studies on the clinical implications of colour matching of tooth-coloured brackets with teeth should now be performed. PMID:18390838

  6. Hydrodynamic Nambu brackets derived by geometric constraints

    NASA Astrophysics Data System (ADS)

    Blender, Richard; Badin, Gualtiero

    2015-03-01

    A geometric approach to derive the Nambu brackets for ideal two-dimensional (2D) hydrodynamics is suggested. The derivation is based on two-forms with vanishing integrals in a periodic domain, and with resulting dynamics constrained by an orthogonality condition. As a result, 2D hydrodynamics with vorticity as dynamic variable emerges as a generic model, with conservation laws which can be interpreted as enstrophy and energy functionals. Generalized forms like surface quasi-geostrophy and fractional Poisson equations for the stream-function are also included as results from the derivation. The formalism is extended to a hydrodynamic system coupled to a second degree of freedom, with the Rayleigh–Bénard convection as an example. This system is reformulated in terms of constitutive conservation laws with two additive brackets which represent individual processes: a first representing inviscid 2D hydrodynamics, and a second representing the coupling between hydrodynamics and thermodynamics. The results can be used for the formulation of conservative numerical algorithms that can be employed, for example, for the study of fronts and singularities.

  7. [The effect of autoclave sterilization on the surface properties of orthodontic brackets after fitting in the mouth].

    PubMed

    Rerhrhaye, W; Ouaki, B; Zaoui, F; Aalloula, E

    2011-12-01

    Repeated sterilizations of the orthodontic bands, after fitting in mouth, are likely to involve modifications of their surface properties. Through this study we have tried to observe the effect of sterilization by autoclave on the surface of the orthodontic bands, as well as the contribution of the use of ultrasound in the chain of sterilization. The sample was composed of 30 orthodontic bands divided into 5 groups: a group of new bands (witnesses) and 4 groups having undergone respectively 1 cycle, 3 cycles, 5 cycles and 7 cycles of autoclave sterilization according to the World Health Organization recommendations. For half of each group bands, ultrasonic cleaning has not been provided. The scanning electron microscopy with the elementary microanalysis by X-rays was used for the investigation of surface. At the exam, new bands showed surface irregularities probably due to manufacturing procedures. And the bands, without ultrasonic cleaning, showed the presence of contamination and discolourations. Moreover, there were no modifications on the surface of the bands cleaned by ultrasounds before sterilization. The presence of surface irregularities associated with deposits observed on the bands surface, may be the site of bio corrosion by contributing bio film accumulation. The stay duration of the orthodontic bands in mouth, during orthodontic treatment, is important. So the effect of sterilization on the surface of the orthodontic bands must encourage other scientific research to determine the long term effects of sterilization which remains an essential process in our daily practice. PMID:22457990

  8. Direct light transmittance through ceramic brackets.

    PubMed

    Eliades, T; Johnston, W M; Eliades, G

    1995-01-01

    The objective of this study was to investigate the degree of direct light transmittance (%T) of various types of esthetic brackets and to correlate these values with their structure, morphologic factors, and composition. Eight types of brackets were used in the study; six brackets of each type were tested. An ultraviolet-visible spectroscopic direct transmission analysis was performed at 320 to 700 nm wavelength range. From each spectrum, the %T corresponded to the peak absorbance wavelength of the photoinitiator of the polymerization was recorded (468 nm). Recorded data were analyzed with one-way analysis of variance and Scheffe's test at alpha = 0.05 significance level. In addition, scanning electron microscope (SEM) images were used to reveal the structure and morphologic factors of the brackets tested. Highest %T values (Mean +/- 1 SD) were obtained from a monocrystal type of bracket (Starfire ["A" Company, San Diego, Calif.] 35.02 +/- 1.59%), followed by a polycrystalline (Fascination [Dentaurum, Pforzhein, Germany] 5.70 +/- 1.41%) and a ceramic/polycarbonate base one (Ceramaflex [TP Orthodontics, Inc., La Porte, Ind.] 4.02 +/- 0.96%). Also other brands presented the following data: Allure (GAC, Central Islip, N.Y.) 3.62 +/- 0.5%; Transcend 2000 (Unitek/3M, Monrovia, Calif.) 2.62 +/- 0.5%; Fascination (edgewise) (Dentaurum, Pforzhein, Germany) 1.97 +/- 0.69%; Lumina (Ormco, Glendora, Calif.) 1.57 +/- 0.5%; Signature (RMO, Denver, Colo.) 1.22 +/- 0.5%. The results showed that the structure, morphologic factors, and composition of the brackets tested were found to affect direct light transmission significantly.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7817957

  9. Sensitivity of titanium brackets to the corrosive influence of fluoride-containing toothpaste and tea.

    PubMed

    Harzer, W; Schröter, A; Gedrange, T; Muschter, F

    2001-08-01

    Titanium brackets are used in orthodontic patients with an allergy to nickel and other specific substances. In recent studies, the corrosive properties of fluoride-containing toothpastes with different pH values were investigated. The present in vivo study tested how the surfaces of titanium brackets react to the corrosive influence of acidic fluoride-containing toothpaste during orthodontic treatment. Molar bands were placed on 18 orthodontic patients. In these same patients, titanium brackets were bonded on the left quadrants and stainless steel brackets on the right quadrants of the upper and lower arches. Fifteen patients used Gel Kam containing soluble tin fluoride (pH 3.2), whereas 3 used fluoride-free toothpaste. The brackets were removed for evaluation by light microscopy and scanning microscopy 5.5 to 7.0 months and 7.5 to 17 months after bonding. The quality and quantity of elements present were measured by scanning microscopy. Macroscopic evaluation showed the matte gray color of titanium brackets dominating over the silver gleam of the steel brackets. The plaque accumulation on titanium brackets is high because of the very rough surface. Pitting and crevices were observed in only 3 of the 165 brackets tested. The present in vivo investigation confirms the results of in vitro studies, but the changes are so minor that titanium brackets can safely be used for up to 18 months. Wing surfaces should be improved by modifying the manufacturing process. PMID:11510642

  10. [Hardened anodized aluminum as a replacement material for bracket manufacture].

    PubMed

    Fischer-Brandies, H; Bönhoff, M

    1994-12-01

    Attention has been repeatedly drawn to the problem of corrosion and the risk of allergic reaction to nickel resulting from the use of stainless steel brackets. In the search for a suitable alternative, manufacturers have turned to thin coating technology using hardened anodized aluminium. Applying resistance to corrosion and abrasion as the criteria to be met, they have selected aluminium alloy type 6082 as the material of choice. Purpose of this study is to examine the physical suitability of this material. Using the above noted alloy, 60 prototype brackets were made with a hardened anodized surface. They were then subjected to the following 3 stress tests: first an abrasion test using a tooth polishing machine, second, a deformation test using a device designed to simulate torque movement, and, third, a corrosion test. The effects on the brackets resulting from the three types of stress were evaluated by light microscopy. A quantitative analysis of the corrosion test was performed by ICP spectrometry. The control group consisted of conventional stainless steel brackets. The light microscopic analysis revealed no evidence of surface damage or signs of deformation in the prototype brackets. The steel brackets, on the other hand, showed clear signs of wear and corrosion. The quantitative analysis of the corrosion solution revealed metallic ion wear of 1.75 ng x mm-2 x h-1 for the prototypes subjected to abrasion. The steel brackets showed at a factor of around 104.6 metallic ion wear of 183 ng x mm-2 x h-1. In addition to this, no Ni ions were found in the corrosion solution of the prototype brackets.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7851828

  11. Calculation of four-particle harmonic-oscillator transformation brackets

    NASA Astrophysics Data System (ADS)

    Germanas, D.; Kalinauskas, R. K.; Mickevi?ius, S.

    2010-02-01

    A procedure for precise calculation of the three- and four-particle harmonic-oscillator (HO) transformation brackets is presented. The analytical expressions of the four-particle HO transformation brackets are given. The computer code for the calculations of HO transformation brackets proves to be quick, efficient and produces results with small numerical uncertainties. Program summaryProgram title: HOTB Catalogue identifier: AEFQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1247 No. of bytes in distributed program, including test data, etc.: 6659 Distribution format: tar.gz Programming language: FORTRAN 90 Computer: Any computer with FORTRAN 90 compiler Operating system: Windows, Linux, FreeBSD, True64 Unix RAM: 8 MB Classification: 17.17 Nature of problem: Calculation of the three-particle and four-particle harmonic-oscillator transformation brackets. Solution method: The method is based on compact expressions of the three-particle harmonics oscillator brackets, presented in [1] and expressions of the four-particle harmonics oscillator brackets, presented in this paper. Restrictions: The three- and four-particle harmonic-oscillator transformation brackets up to the e=28. Unusual features: Possibility of calculating the four-particle harmonic-oscillator transformation brackets. Running time: Less than one second for the single harmonic-oscillator transformation bracket. References:G.P. Kamuntavi?ius, R.K. Kalinauskas, B.R. Barret, S. Mickevi?ius, D. Germanas, Nuclear Physics A 695 (2001) 191.

  12. Corrosion behavior of self-ligating and conventional metal brackets

    PubMed Central

    Maia, Lúcio Henrique Esmeraldo Gurgel; Lopes Filho, Hibernon; Ruellas, Antônio Carlos de Oliveira; Araújo, Mônica Tirre de Souza; Vaitsman, Delmo Santiago

    2014-01-01

    Objective To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. Methods Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek) and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek) metal brackets from three manufacturers (n = 150) were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± 1ºC for 21 days. The content of nickel, chromium and iron ions in the solution collected at intervals of 7, 14 and 21 days was quantified by atomic absorption spectrophotometry. After the aging process, the brackets were analyzed by scanning electron microscopy (SEM) under 22X and 1,000X magnifications. Results Comparison of metal release in self-ligating and conventional brackets from the same manufacturer proved that the SCs group released more nickel (p < 0.05) than the GN group after 7 and 14 days, but less chromium (p < 0.05) after 14 days and less iron (p < 0.05) at the three experimental time intervals. The INs group released less iron (p < 0.05) than the GE group after 7 days and less nickel, chromium and iron (p < 0.05) after 14 and 21 days. The ECs group released more nickel, chromium and iron (p < 0.05) than the VE group after 14 days, but released less nickel and chromium (p < 0.05) after 7 days and less chromium and iron (p < 0.05) after 21 days. The SEM analysis revealed alterations on surface topography of conventional and self-ligating brackets. Conclusions The aging process in self-ligating brackets was not greater than in conventional brackets from the same manufacturer. The null hypothesis was accepted. PMID:24945521

  13. Prevention of demineralization around orthodontic brackets using two different fluoride varnishes

    PubMed Central

    Nalbantgil, Didem; Oztoprak, Mehmet Oguz; Cakan, Derya Germec; Bozkurt, Kemal; Arun, Tulin

    2013-01-01

    Objective: This in-vitro study was done to evaluate the effects of two different seal materials, Duraflor™ and Enamel Pro® Varnish, on enamel demineralization adjacent to orthodontic fixed appliances. Methods: Seventy-two extracted solid premolars were allocated to three groups as one control and two study groups after brackets were placed and bonded with Transbond™ XT. The control group received no topical fluoride application after bonding, whereas in the study groups two fluoride varnishes, Enamel Pro® Varnish and Duraflor™ were applied on the teeth adjacent to brackets. All specimens were then immersed separately in demineralization solution for 96 hours at constant temperature. Demineralization of the enamel surface was evaluated quantitatively by cross-sectional microhardness testing: indentations were made at the edge of the bracket base (0 ?m) and at 100 and 200 ?m distant from it. In all of these positions, 5 indentations were made at 10, 20, 40, 70 and 90 ?m of depths from the external surface of the enamel. Results: The results revealed that, Enamel Pro® Varnish and Duraflor™ group values are higher than the values of control group at every depth. The differences between the depths showed that the microhardness values decreased significantly when the depth increased. In the control group, more demineralization occurred in every indentation compared to the study group. Conclusion: Duraflor™ and Enamel Pro® Varnish can be considered for use in clinic as an effective method to prevent or reduce demineralization during orthodontic treatment, especially in patients with poor oral hygiene. PMID:23408742

  14. Direct light transmittance through ceramic brackets

    Microsoft Academic Search

    Theodore Eliades; William M. Johnston; George Eliades

    1995-01-01

    The objective of this study was to investigate the degree of direct light transmittance (%T) of various types of esthetic brackets and to correlate these values with their structure, morphologic factors, and composition. Eight types of brackets were used in the study; six brackets of each type were tested. An ultraviolet-visible spectroscopic direct transmission analysis was performed at 320 to

  15. Effects of oil-based and oil-free enamel prophylactic agents on bracket failure--a prospective randomized clinical trial.

    PubMed

    Magnius, Magdalena; Bazargani, Farhan

    2014-01-01

    This study evaluates and compares the effects of enamel prophylaxis using either oil-free pumice or oil-containing prophylaxis paste on the incidence of bracket failure in orthodontic patients. Forty-six orthodontic patients participated in this prospective clinical trial. A cross-mouth method was used in each patient, in which two diagonal quadrants (i.e. upper right and lower left or vice versa) were randomly assigned to the pumice group and the contralateral diagonal quadrants to the Prophy Paste group. A total of 836 teeth were bonded using Transbond XT (3M Unitek) and monitored for an average of 23 months for bond failure. Chi-square analysis was used to compare the number of bracket failures between the groups. Overall, 26 bond failures occurred by the end of the trial. Fifteen bracket failures were observed in the Prophy Paste group (3.6%) and 11 in the pumice group (2.6%). The failure rates were fairly evenly distributed between the upper and lower jaws. There were no statistically significant differences between the groups (P = 0.43). This study showed that enamel prophylaxis using either pumice or Prophy Paste before orthodontic bonding works equally well in a clinical setting. PMID:25102719

  16. Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.

    PubMed

    Deguchi, T; Ito, M; Obata, A; Koh, Y; Yamagishi, T; Oshida, Y

    1996-07-01

    Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application. PMID:8876601

  17. Physical and chemical properties of orthodontic brackets after 12 and 24 months: in situ study

    PubMed Central

    MENDES, Bernardo de Azevedo Bahia; FERREIRA, Ricardo Alberto Neto; PITHON, Matheus Melo; HORTA, Martinho Campolina Rebello; OLIVEIRA, Dauro Douglas

    2014-01-01

    Objective The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. Material and Methods Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide® elastomeric ligature. Results The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface. Conclusion The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction. PMID:25025560

  18. Effect of fluoride on friction between bracket and wire

    PubMed Central

    Alavi, Shiva; Farahi, Ali

    2011-01-01

    Background: Friction is usually encountered during sliding technique for orthodontic space closure. This study aims to investigate the effect of fluoride on frictional resistance between stainless steel orthodontic brackets and steel and NiTi arch wires. Materials and Methods: A total of 144 standard 022 stainless steel brackets were used in this experimental study. 0.016 and 0.019 × 0.025 inch steel and NiTi arch wires were tested. The frictional resistance between wires and brackets immersed in the following three solutions were measured: Sultan fluoride gel containing 1.23% acidulated phosphate fluoride at pH 3.5 for 4 minutes, aquafresh mouth wash containing 0.05% sodium fluoride at pH of 5.1 for 1 minute twice a day for 8 weeks and physiologic serum (pH=7) as the control group. Static and dynamic frictional forces were measured using Testometric machine. Surface topography of wires and brackets was qualitatively assessed using electron microscopy. Three-way and two-way variance analysis and complementary Tuckey analysis were applied to compare the groups for any significant differences (P<0.05). Results: The average static and dynamic frictional forces for all bracket-wire combinations immersed in Sultan fluoride gel were higher than those immersed in NAF and control groups (P<0.001).The forces measured for rectangular wires were higher than round wires (P<0.001). Frictional resistance of 0.016 inch NiTi wire was more than that of the steel one but the difference between steel and NiTi 0.019 × 0.25 arch wires was not significant. Conclusion: Friction between steel brackets and nickel titanium and steel wires is affected by prophylactic agents containing high doses of fluoride and acidity. PMID:23372594

  19. Gingival response in orthodontic patients: Comparative study between self-ligating and conventional brackets.

    PubMed

    Folco, Alejandra A; Benítez-Rogé, Sandra C; Iglesias, Marina; Calabrese, Diana; Pelizardi, Cristina; Rosa, Alcira; Brusca, Marisa I; Hecht, Pedro; Mateu, María E

    2014-01-01

    Orthodontic brackets contribute to the accumulation of bacterial plaque on tooth surfaces because they hinder oral hygiene. In contrast to conventional brackets, self-ligating brackets do not require additional parts to support the arches, thus improving dental hygiene. The aim of this study was to compare the gingival response in orthodontic patients wearing self-ligating or conventional brackets. A sample of 22 patients aged 16 to 30 years was divided into two groups: Group A, treated with selfligating brackets (Damon system) and Group B, treated with conventional brackets (Roth technique). The following were assessed during the treatment: Plaque Index (PI), Gingival Index (GI) and Probing Depth (PD), and sub-gingival samples were taken from teeth 14/24 for microbiological observation. No statistically significant difference was found between Groups A and B; p>0.05 (sign-ranked) or between PI, GI and PD at the different times (Friedman's Analysis of Variance), even though the indices were found to increase at 14 days, particularly for self-ligating brackets. The quantity and quality of microorganisms present were compatible with health on days 0, 28 and 56. As from day 14 there is a predominance of microbiota compatible with gingivitis in both groups. In the samples studied, orthodontic treatment increases bacterial plaque and inflammatory gingival response, but gingival-periodontal health can be maintained with adequate basic therapy. Self-ligating and conventional brackets produced similar gingival response. PMID:25560690

  20. 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

  1. Transformation brackets for harmonic oscillator functions

    Microsoft Academic Search

    M. Moshinsky

    1959-01-01

    The transformation brackets connecting the wave functions for two ; particles in a harmonic oscillator common potential with the wave functions given ; in terms of the relative and center-of-mass coordinates of the two particles are ; defined. With the help of these brackets it is shown that oil matrix elements ; for the interaction potentials in nuclear shell theory

  2. Ultrashort pulsed laser conditioning of human enamel: in vitro study of the influence of geometrical processing parameters on shear bond strength of orthodontic brackets.

    PubMed

    Lorenzo, M C; Portillo, M; Moreno, P; Montero, J; García, A; Santos-del Riego, S E; Albaladejo, A

    2015-02-01

    The surfaces of 63 extracted premolar teeth were processed with intense ultrashort laser pulses (??=?795 nm; pulse duration, 120 fs; repetition rate, 1 kHz) to produce cross patterns with different pitches (s) in the micrometer range in order to evaluate the influence of such microstructures on the shear bond strengths of orthodontic brackets to enamel. The samples were classified in nine groups corresponding to the control group (raw samples) and eight different laser-processed groups (cross patterns with s increasing from 15 to 180 ?m). Brackets were luted with Transbond(TM) XT adhesive resin to all the samples; after 72 h, they all were submitted to strength test in a universal testing machine. Additionally, a third of the samples underwent morphological analysis of the debonded surface by means of scanning electron microscope microscopy and an analysis of the failure mode based on the adhesive remnant index. The results showed that enamel microstructuring with ultrashort laser pulses remarkably increase the bond strength of brackets. Dense cross patterns (s??90 ?m) give rise to smaller improvements of the bond strength. A strong correlation of this behavior with the predominant failure mode in both scenarios was found. So far, the best compromise between suitable adhesive efficiency, processing time minimization, and enamel surface preservation suggests the performance of cross patterns with pitches in the order of 90 ?m. PMID:24249356

  3. Comparison of Microleakage under Rebonded Stainless Steel Orthodontic Brackets Using Two Methods of Adhesive Removal: Sandblast and Laser

    PubMed Central

    Tudehzaeim, Mohamad Hossein; Yassaei, Soghra; Taherimoghadam, Shohreh

    2015-01-01

    Objectives: Debonding is a common occurrence in orthodontic treatment and a considerable number of orthodontists prefer to rebond the detached brackets because of economic issues. The aim of this study was to compare the microleakage beneath rebonded stainless steel brackets using two methods of adhesive removal namely sandblast and laser. Materials and Methods: Sixty human premolar teeth were randomly divided into three groups. Following bonding the brackets, group 1 served as the control group. Brackets in groups 2 and 3 were debonded, and adhesive removal from the bracket bases was done by means of sandblasting and Er-YAG laser, respectively. After rebonding, teeth in each group were stained with 2% methylene blue for 24 hours, sectioned and examined under a stereomicroscope. Marginal microleakage at the adhesive-enamel and bracket-adhesive interfaces in the occlusal and gingival margins was determined. Statistical analysis was done using the Kruskal-Wallis test. Results: Comparison of the microleakage scores among the three groups revealed no statistically significant difference (P > 0.05). At the enamel-adhesive interface, the gingival margins in all groups showed higher microleakage while in the adhesive-bracket interface, the occlusal margin exhibited greater microleakage. Conclusion: Er-YAG laser irradiation and sandblasting for adhesive removal from the debonded brackets yielded clinically acceptable microleakage scores.

  4. Effect of acetic NaF solution on the corrosion behavior of stainless steel orthodontic brackets.

    PubMed

    Jang, Hee-Song; Son, Woo-Sung; Park, Soo-Byung; Kim, Hyung-Il; Yong, Hoon Kwon

    2006-06-01

    This study assessed the effect of acetic NaF solutions on stainless steel orthodontic brackets. Acetic acid was added to a 0.1% NaF solution to make two solutions, one with pH 3.5 and the other with pH 6. For the two different stainless steel brackets (Tomy, Dentaurum) used in this study, they had a similar elemental composition--except with Mo (molybdenum) in the Tomy bracket. The brackets were then immersed in the prepared test solutions for three days and their responses evaluated. In terms of hydrofluoric acid (HF) concentration, the 0.1%/pH 3.5 solution showed a high HF concentration at 227 ppm, while that of 0.1%/pH 6 solution was very low at 7 ppm. In terms of color change and element release, only the Dentaurum brackets in 0.1%/pH 3.5 solution showed an appreciable color change (deltaE* = 4.0) and released a great amount of elements (Fe, Cr, Ni, Mn) after three days. Otherwise, regardless of pH value and product, only minor color change (deltaE* < 1.0) and negligible element release occurred. In terms of surface modification, no visible changes in surface morphology were observed in any product after immersion in test solutions. PMID:16916238

  5. Adjustable Bracket For Entry Of Welding Wire

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.; Gutow, David A.

    1993-01-01

    Wire-entry bracket on welding torch in robotic welding system provides for adjustment of angle of entry of welding wire over range of plus or minus 30 degrees from nominal entry angle. Wire positioned so it does not hide weld joint in view of through-the-torch computer-vision system part of robot-controlling and -monitoring system. Swiveling bracket also used on nonvision torch on which wire-feed-through tube interferes with workpiece. Angle simply changed to one giving sufficient clearance.

  6. Retrieval analysis of different orthodontic brackets: the applicability of electron microprobe techniques for determining material heterogeneities and corrosive potential

    PubMed Central

    HOLST, Alexandra Ioana; HOLST, Stefan; HIRSCHFELDER, Ursula; von SECKENDORFF, Volker

    2012-01-01

    Objective The objective of this study was to investigate the applicability of micro-analytical methods with high spatial resolution to the characterization of the composition and corrosion behavior of two bracket systems. Material and methods The surfaces of six nickel-free brackets and six nickel-containing brackets were examined for signs of corrosion and qualitative surface analysis using an electron probe microanalyzer (EPMA), prior to bonding to patient's tooth surfaces and four months after clinical use. The surfaces were characterized qualitatively by secondary electron (SE) images and back scattered electron (BSE) images in both compositional and topographical mode. Qualitative and quantitative wavelength-dispersive analyses were performed for different elements, and by utilizing qualitative analysis the relative concentration of selected elements was mapped two-dimensionally. The absolute concentration of the elements was determined in specially prepared brackets by quantitative analysis using pure element standards for calibration and calculating correction-factors (ZAF). Results Clear differences were observed between the different bracket types. The nickel-containing stainless steel brackets consist of two separate pieces joined by a brazing alloy. Compositional analysis revealed two different alloy compositions, and reaction zones on both sides of the brazing alloy. The nickel-free bracket was a single piece with only slight variation in element concentration, but had a significantly rougher surface. After clinical use, no corrosive phenomena were detectable with the methods applied. Traces of intraoral wear at the contact areas between the bracket slot and the arch wire were verified. Conclusion Electron probe microanalysis is a valuable tool for the characterization of element distribution and quantitative analysis for corrosion studies. PMID:23032212

  7. Interior view, detail to show typical bracket with gold leaf ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view, detail to show typical bracket with gold leaf ornament, here the bracket is located the north of the speaker on the second floor - National Park Seminary, Ballroom, Linden Lane, Silver Spring, Montgomery County, MD

  8. Ceramic bracket debonding with the carbon dioxide laser

    Microsoft Academic Search

    Jeff L. Rickabaugh; Roy D. Marangoni; Kristine K. McCaffrey

    1996-01-01

    The conventional removal of ceramic brackets can be complicated by bracket fracture or enamel loss. To ease this ceramic bracket removal, lasers have been previously investigated for thermally softening thermally the bonding resin. This conversion of laser light to heat can also threaten the vitality of the debonded teeth. Pilot studies and computer modeling suggest that for commonly used polycrystalline

  9. A bracket polynomial for graphs. III. Vertex weights

    Microsoft Academic Search

    Lorenzo Traldi

    2009-01-01

    In earlier work the Kauffman bracket polynomial was extended to an invariant of marked graphs, i.e., looped graphs whose vertices have been partitioned into two classes (marked and not marked). The marked-graph bracket polynomial is readily modified to handle graphs with weighted vertices. We present formulas that simplify the computation of this weighted bracket for graphs that contain twin vertices

  10. Optimal enamel conditioning strategy for rebonding orthodontic brackets: a laboratory study

    PubMed Central

    Zhang, Qi-Feng; Yao, Hua; Li, Zhi-Yong; Jin, Li; Wang, Hui-Ming

    2014-01-01

    Objective: To compare the conventional etching and primer method (CEP) and the self-etching primer method (SEP) in rebonding brackets. Methods: Forty human maxillary second premolars extracted for orthodontic purpose were randomly divided into 4 equal groups. Group 1 and Group 2 were bonded using the CEP method; Group 3 and Group 4 using the SEP method. All the brackets were debonded and 40 new brackets were rebonded with four different protocols after surface cleaning: Group 1: CEP + adhesive; Group 2: CEP without etch step + adhesive; Group 3: SEP + adhesive; Group 4: non-acidic primer + adhesive. Then, the shear bond strength (SBS) of each group was tested and the measurements of adhesive remnant index scores (ARI) and SEM examination were performed. Results: The mean SBSs for Group 1, 2, 3 and 4 were 14.18, 6.57, 11.90, 5.91 MPa, respectively. Statistical differences of the SBS existed between Group 1 and 2 (P < 0.05) and between Group 3 and 4 (P < 0.05). No difference was found between Group 1 and 3, or Group 2 and 4. Conclusion: Omission of the acid-etching step in rebonding orthodontic brackets may be adequate for the clinical requirement. No differences in SBS and ARI of the rebonded brackets were showed between CEP and SEP methods. PMID:25356128

  11. Pulpal Thermal Changes following Er-YAG Laser Debonding of Ceramic Brackets

    PubMed Central

    Oztoprak, Mehmet Oguz

    2014-01-01

    Lasers are effective in debonding ceramic brackets. Unfortunately, while reducing the adhesive bond strength, lasers are also reported to increase pulpal temperature. The aim of this study was to evaluate the shear bond strengths and temperature increase levels after debonding ceramic brackets using an Er-YAG laser with or without water-cooling. Sixty polycrystalline upper premolar ceramic brackets were placed on the labial surface of sixty human premolar teeth which were randomly divided into three groups of twenty. A laser pulse at 5?W for 9 seconds was delivered to each bracket in both study groups either with water-cooling (water group) or without water-cooling (waterless group) using an Er-YAG laser. Debonding was performed 45 seconds after laser exposure and shear bond strengths were measured. Data comparison revealed a statistically significant difference between the groups. Mean temperature increases of 2.41°C and 4.59°C were recorded for the water and waterless laser groups, respectively. The shear bond strength value for the control group was 22.76?MPa and 10.46 and 6.36?MPa for the water and waterless laser groups, respectively. The application of Er-YAG laser with water-cooling was an efficient and safe method of debonding ceramic brackets. PMID:25197718

  12. Are the low-shrinking composites suitable for orthodontic bracket bonding?

    PubMed Central

    Buyuk, Suleyman Kutalmis; Cantekin, Kenan; Demirbuga, Sezer; Ozturk, Mehmet Ali

    2013-01-01

    Purpose: To evaluate the shear bond strength (SBS), adhesive remnant index (ARI), and microleakage of low-shrinking and conventional composites used as an orthodontic bracket bonding adhesive. Materials and Methods: A hundred twenty non-caries human premolars, extracted for orthodontic purposes, were used in this study. Sixty of them were separated into two groups. Brackets were bonded to the teeth in the test group with Silorane (3M-Espe) and control group with Transbond-XT (3M-Unitek). SBS values of these brackets were recorded in MPa using a universal testing machine. ARI scores were determined after the failure of brackets. The remaining 60 teeth were divided into two groups and microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson Chi-square, and Mann–Whitney U tests at P < 0.05 level. Results: The mean SBS for Transbond XT was significantly greater than low-shrinking composite (P < 0.001). Significant differences (?2 =29.60, P < 0.001) were present between the two groups for the ARI scores. Microleakage values were lower in low-shrinking composite than in the control group, and this difference was found to be statistically significant (P < 0.001). Conclusions: Although low-shrinking composite produced insufficient SBS and ARI scores, microleakage values were lower in low-shrinking composite than in the control group on the etched enamel surfaces, when used as a bracket bonding composite. PMID:24926207

  13. Evaluation of friction of conventional and metal-insert ceramic brackets in various bracket-archwire combinations

    Microsoft Academic Search

    Vittorio Cacciafesta; Maria Francesca Sfondrini; Andrea Scribante; Catherine Klersy; Ferdinando Auricchio

    The purpose of the study was to measure and compare the level of frictional resistance generated between conventional ceramic brackets (Transcend Series 6000, 3M Unitek, Monrovia, Calif), ceramic brackets with stainless steel slot (Clarity, 3M Unitek), conventional stainless steel brackets (Victory Series, 3M Unitek), and 3 different orthodontic wire alloys: stainless steel (stainless steel, SDS Ormco, Glendora, Calif), nickel- titanium

  14. Search Engine Statistics Beyond the n-gram: Application to Noun Compound Bracketing

    Microsoft Academic Search

    Preslav Nakov; Marti Hearst

    2005-01-01

    In order to achieve the long-range goal of semantic interpretation of noun com- pounds, it is often necessary to £rst de- termine their syntactic structure. This pa- per describes an unsupervised method for noun compound bracketing which extracts statistics from Web search engines using a ´2 measure, a new set of surface features, and paraphrases. On a gold standard, the

  15. Numerical integration methods for the double-bracket flow

    NASA Astrophysics Data System (ADS)

    Casas, Fernando

    2004-04-01

    In this paper new methods up to order four based on the Magnus expansion are proposed for the numerical integration of the double-bracket equation. The Magnus series is constructed term-by-term by means of recurrences and a bound on the convergence domain is also provided. The new integrators preserve the most salient qualitative features of the flow and are computationally more efficient than other standard Lie-group solvers, such as the Runge-Kutta-Munthe-Kaas class of algorithms.

  16. Effect of bracket bonding with Er: YAG laser on nanomechanical properties of enamel

    PubMed Central

    Alavi, Shiva; Birang, Reza; Hajizadeh, Fatemeh; Banimostafaee, Hamed

    2014-01-01

    Background: The aim of this study was to compare the effects of conventional acid etching and laser etching on the nano-mechanical properties of the dental enamel using nano-indentation test. Materials and Methods: In this experimental in vitro study, buccal surfaces of 10 premolars were divided into three regions. One of the regions was etched with 37% phosphoric acid and another etched with Er:YAG laser, the third region was not etched. The brackets were bonded to both of etched regions. After thermocycling for 500 cycles, the brackets were removed and the teeth were decoronated from the bracket bonding area. Seven nano-indentations were applied at 1-31 ?m depth from the enamel surface in each region. Mean values of the hardness and elastic modulus were analyzed with repeated measures analysis of variance and Tukey HSD tests, using the SPSS software (SPSS Inc., version16.0, Chicago, Il, USA). P < 0.05 was considered as significant. Results: The hardness up to 21 ?m in depth and elastic modulus up to 6 ?m in depth from the enamel surface for laser-etched enamel had significantly higher values than control enamel and the hardness up to 11 ?m in depth and elastic modulus up to 6 ?m in depth for acid-etched enamel had significantly lower values than the control enamel. Conclusion: The mechanical properties of the enamel were decreased after bracket bonding with conventional acid etching and increased after bonding with Er:YAG laser. PMID:24688560

  17. CO2 laser debonding of a ceramic bracket bonded with orthodontic adhesive containing thermal expansion microcapsules.

    PubMed

    Saito, Ayano; Namura, Yasuhiro; Isokawa, Keitaro; Shimizu, Noriyoshi

    2015-02-01

    We have been studying an easy bracket debonding method using heating of an orthodontic adhesive containing thermal expansion microcapsules. However, heating with a high-temperature heater brings obvious risks of burns around the oral cavity. Thus, we examined safer and more effective bracket debonding methods. The purpose of this in vitro study was to examine the reduction in debonding strength and the time taken using a bracket bonded with an orthodontic adhesive containing thermal expansion microcapsules and a CO2 laser as the heating method while maintaining safety. Ceramic brackets were bonded to bovine permanent mandibular incisors using bonding materials containing various microcapsule contents (0, 30, and 40 wt%), and the bond strengths were measured after laser irradiation for 4, 5, and 6 s and compared with nonlaser-treated groups. Subsequently, the temperature in the pulp chamber during laser irradiation was measured. After laser irradiation for 5 or 6 s, the bond strengths of the adhesive containing 40 wt% microcapsules were significantly decreased to ?0.40?-?0.48-fold (4.6-5.5 MPa) compared with the nonlaser groups. The mean temperature rise of the pulp chamber was 4.3 °C with laser irradiation for 6 s, which was less than that required to induce pulp damage. Based on these results, we conclude that the combined use of a CO2 laser and an orthodontic adhesive containing thermal expansion microcapsules can be effective and safe for debonding ceramic brackets with less enamel damage or tooth pain. PMID:24220847

  18. A stainless steel bracket for orthodontic application.

    PubMed

    Oh, Keun-Taek; Choo, Sung-Uk; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2005-06-01

    Aesthetics has become an essential element when choosing orthodontic fixed appliances. Most metallic brackets used in orthodontic therapy are made from stainless steel (SS) with the appropriate physical properties and good corrosion resistance, and are available as types 304, 316 and 17-4 PH SS. However, localized corrosion of these materials can frequently occur in the oral environment. This study was undertaken to evaluate the accuracy of sizing, microstructure, hardness, corrosion resistance, frictional resistance and cytotoxicity of commercially available Mini-diamond (S17400), Archist (S30403) and experimentally manufactured SR-50A (S32050) brackets. The size accuracy of Mini-diamond was the highest at all locations except for the external horizontal width of the tie wing (P < 0.05). Micrographs of the Mini-diamond and Archist showed precipitates in the grains and around their boundaries. SR-50A showed the only austenitic phase and the highest polarization resistance of the tested samples. SR-50A also had the highest corrosion resistance [SR-50A, Mini-diamond and Archist were 0.9 x 10(-3), 3.7 x 10(-3), and 7.4 x 10(-3) mm per year (mpy), respectively], in the artificial saliva. The frictional force of SR-50A decreased over time, but that of Mini-diamond and Archist increased. Therefore, SR-50A is believed to have better frictional properties to orthodontic wire than Mini-diamond and Archist. Cytotoxic results showed that the response index of SR-50A was 0/1 (mild), Mini-diamond 1/1 (mild+), and Archist 1/2 (mild+). SR-50A showed greater biocompatibility than either Mini-diamond or Archist. It is concluded that the SR-50A bracket has good frictional property, corrosion resistance and biocompatibility with a lower probability of allergic reaction, compared with conventionally used SS brackets. PMID:15947222

  19. Derived Bracket Construction and Manin Products

    Microsoft Academic Search

    Kyousuke Uchino

    2010-01-01

    We will extend the classical derived bracket construction to any algebra over a binary quadratic operad. We will show that\\u000a the derived product construction is a functor given by the Manin white product with the operad of permutation algebras. As\\u000a an application, we will show that the operad of prePoisson algebras is isomorphic to the Manin black product of the

  20. Conceptual design for PSP mounting bracket

    SciTech Connect

    Ransom, G.; Stein, R.

    1991-08-16

    Protective structural packages (PSP's or overpacks) used to ship 2{1/2}-ton UF product cylinders are bolted to truck trailers. All bolts penetrate two longitudinal rows of wooden planks. Removal and replacement is required at various intervals for maintenance and routine testing. A conceptual design is presented for mounting brackets which would securely attach PSP's to trailer frames, reduce removal and replacement time, and minimize risk of personnel injury. 1 ref., 2 figs.

  1. Effect of different preventive agents on bracket shear bond strength: in vitro study

    PubMed Central

    2014-01-01

    Background The effects of fluoride and CPP-ACP before bracket bonding on the shear bond strength of orthodontic brackets have been reported with contradicting results. The objective of this in vitro study was to evaluate the effect of different preventive agents namely; casein phosphopeptide-amorphous-calcium-phosphate (CPP-ACP), fluoride-containing-CPP-ACP (CPP-ACPF) and 5% sodium fluoride (5% NaF), on the enamel-bracket shear bond strength (SBS) and to compare their effects when applied before or after acid-etching. Methods Human premolar teeth were randomly divided into seven groups (16 teeth per group) as follows: the control group, where no preventive agent was applied on the enamel and 6 experimental groups. Teeth in groups 1a, 2a, and 3a were treated with CPP-ACP paste, CPP-ACPF paste, and 5% NaF, respectively before acid-etching. Teeth in groups 1b, 2b and 3b were treated using the same preventive agents after acid-etching. The brackets were then bonded and the teeth were thermocycled. The brackets' SBS was measured and the adhesive remnant was assessed using adhesive remnant index (ARI). Analysis of variance (ANOVA) and Tukey test were performed to compare the SBS among different groups. Chi-square test was used to evaluate differences in ARI scores between the groups. Results Enamel surface treatment with CPP-ACPF after acid-etching significantly increased SBS compared to the control and to its application before acid-etching (P?Brackets' SBS significantly increased when fluoride-containing-CPP-ACP was applied after acid-etching. PMID:24678892

  2. In Vitro Evaluation of Microleakage Around Orthodontic Brackets Using Laser Etching and Acid Etching Methods

    PubMed Central

    Toodehzaeim, Mohammad Hossein; Yassaei, Sogra; Karandish, Maryam; Farzaneh, Sedigeh

    2014-01-01

    Objective: path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques. Materials and Method: The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1), laser etching with Er:YAG at 100 mJ and 15 Hz for 15s (group 2), and laser etching with Er:YAG at 140 mJ and 15 Hz for 15s (group 3). After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred between the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test. Results: For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups. Conclusion: According to this study, the Er:YAG laser with 1.5 and 2.1 watt settings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding. PMID:25628661

  3. Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires

    PubMed Central

    Leite, Vanessa Vieira; Lopes, Murilo Baena; Gonini Júnior, Alcides; de Almeida, Marcio Rodrigues; Moura, Sandra Kiss; de Almeida, Renato Rodrigues

    2014-01-01

    Objective To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. Material and Methods Abzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a ligating wire 0.10-in was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa) were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM. Results Steel-tied brackets (16.48 ± 8.31) showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 ) and self-ligating brackets (1.66 ± 1.57) (P < 0.05), which also differed from each other (P < 0.05). As for the type of wire, 0.019 x 0.025-in steel wire (5.67 ± 3.97) showed lower means (P < 0.05) than 0.16-in NiTi wire (8.26 ± 10.92) and 0.016 x 0.021-in NiTi wire (8.51 ± 7.95), which did not differ from each other (P > 0.05). No statistical differences (P > 0.05) were found between zero (7.76 ± 8.46) and five-degree (7.19 ± 7.93) angulations. Conclusions Friction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied PMID:25162575

  4. A quantum-classical bracket that satisfies the Jacobi identity

    SciTech Connect

    Prezhdo, Oleg V. [Department of Chemistry, University of Washington, Seattle, Washington 98195-1700 (United States)

    2006-05-28

    A quantum-classical bracket is proposed and is shown to satisfy the Jacobi identity, in contrast to previous definitions that obey this property only up to higher order terms in the Planck constant ({Dirac_h}/2{pi}). The Jacobi identity is required of a true Lie bracket and ensures that the Lie bracket of constants of motion is also a constant of motion. An explicit calculation of the Jacobi identity highlights the difference between the proposed and traditional definitions. A further example illustrates that the proposed bracket generates a more consistent quantum-classical dynamics than the traditional bracket. The traditional quantum-classical dynamics in the Henon-Heiles system diverges due to higher order ({Dirac_h}/2{pi}) terms. The divergence is eliminated with the proposed bracket.

  5. Orthodontic bracket designs and their impact on microbial profile and periodontal disease: A clinical trial

    PubMed Central

    Moolya, Nikesh N; Shetty, Arvind; Gupta, Neha; Gupta, Anvesha; Jalan, Vivek; Sharma, Rashmi

    2014-01-01

    Aim: The aim of the present study was to compare the undisturbed plaque formation on teeth bonded with Preadjusted (Captain Ortho, Libral Traders, Mumbai, India) and Begg Brackets (Captain Ortho, Libral Traders, Mumbai, India) with nonbonded control sites via a de novo plaque growth over a period of 7 days. Materials and Methods: A clinical trial with the split-mouth design was set up enrolling 10 dental students. Within each subject sites with (Preadjusted) (P-site), Begg brackets (B-site) and control sites were followed. Plaque index and gingival index were recorded on days 3 and 7. Supra-gingival and sub-gingival plaque samples were taken from the brackets and the teeth on days 3 and 7, and were sent for aerobic and anaerobic culturing. The total number of bacterial colony forming units (CFU) was assessed for each sample using a colony counter. Tukeys and Dunnett test then statistically analyzed data. Results: The mean plaque index and gingival index increased on P-site and B-site on the third and 7th day. The shift from aerobic to anaerobic species was observed earlier in P-sites than in B-sites. The CFU were significantly higher for all sites on day 7 when compared with day 3. The aerobe/anaerobe CFU ratio was significantly lower in P-sites than in B-sites and then control showing an increase in the number of anaerobic species on the 3rd and 7th day (P < 0.05). Based on observed means, the mean difference was significant (P < 0.05). Conclusion: The present data suggest that Preadjusted brackets accumulated more plaque than Begg brackets. Bracket design can have a significant impact on bacterial load and on periodontal parameters. PMID:25426456

  6. New infinite-dimensional algebras, sine brackets, and SU (infinity)

    SciTech Connect

    Zachos, C.K.; Fairlie, D.B.

    1989-01-01

    We investigate the infinite dimensional algebras we have previously introduced, which involve trigonometric functions in their structure constants. We find a realization for them which provides a basis-independent formulation, identified with the algebra of sine brackets. A special family of them, the cyclotomic ones, contain SU(N) as invariant subalgebras. In this basis, it is evident by inspection that the algebra of SU(infinity) is equivalent to the centerless algebra of SDiff/sub 0/ on two-dimensional manifolds. Gauge theories of SU(infinity) are thus simply reformulated in terms of surface (sheet) coordinates. Spacetime-independent configurations of their gauge fields describe strings through the quadratic Schild action. 11 refs.

  7. The Poisson bracket on free null initial data for gravity.

    PubMed

    Reisenberger, Michael P

    2008-11-21

    Free initial data for general relativity on a pair of intersecting null hypersurfaces are well known, but the lack of Poisson brackets and concerns about caustics have stymied the development of a constraint free canonical theory. Here it is pointed out how caustics and generator crossings can be neatly avoided and Poisson brackets on free data are given. On sufficiently regular functions of the solution spacetime geometry these brackets match the Poisson brackets defined on such functions by the Hilbert action via Peierls' prescription. The symplectic 2-form is also given in terms of free data. PMID:19113400

  8. Derived Bracket Construction and Manin Products

    NASA Astrophysics Data System (ADS)

    Uchino, Kyousuke

    2010-07-01

    We will extend the classical derived bracket construction to any algebra over a binary quadratic operad. We will show that the derived product construction is a functor given by the Manin white product with the operad of permutation algebras. As an application, we will show that the operad of prePoisson algebras is isomorphic to the Manin black product of the Poisson operad with the preLie operad. We will show that differential operators and Rota-Baxter operators are, in a sense, Koszul-dual to each other.

  9. Evaluation of friction of conventional and metal-insert ceramic brackets in various bracket-archwire combinations

    Microsoft Academic Search

    Vittorio Cacciafesta; Maria Francesca Sfondrini; Andrea Scribante; Catherine Klersy; Ferdinando Auricchio

    2003-01-01

    The purpose of the study was to measure and compare the level of frictional resistance generated between conventional ceramic brackets (Transcend Series 6000, 3M Unitek, Monrovia, Calif), ceramic brackets with stainless steel slot (Clarity, 3M Unitek), conventional stainless steel brackets (Victory Series, 3M Unitek), and 3 different orthodontic wire alloys: stainless steel (stainless steel, SDS Ormco, Glendora, Calif), nickel-titanium (Ni-Ti,

  10. Effect of toothbrushing with different manual toothbrushes on the shear bond strength of orthodontic brackets.

    PubMed

    Oliveira, Guilherme José Pimentel Lopes de; Pavone, Chaine; Costa, Maurício Ribeiro; Marcantonio, Rosemary Adriana Chiérici

    2010-01-01

    The aim of this study was to evaluate the effect of brushing with a Colgate 360º or Oral B Indicator 35 toothbrush on the shear bond strength of orthodontic brackets bonded to extracted human teeth. The bristle wear and bristle tip morphology were also examined after simulated tooth-brushing. Orthodontic brackets (Roth-P/1st and 2nd premolar S/D- Slot 0.18") were bonded (Transbond XT) to the smoothest surface of each of 45 extracted human molar and premolar teeth. Test specimens were randomly divided into three groups: Group 1, control group with no brushing; Group 2, brushing with the Oral B Indicator 35; Group 3, brushing with the Colgate 360º. Samples were adapted to a machine that simulated tooth-brushing. The bond strength of each bracket to each tooth was assessed with a mechanical testing machine. The bristle wear and bristle tip morphology indices were also assessed. Statistically significant differences were defined for p < 0.05. The average bond strengths (range: 90.18-90.89 kgf/cm²) did not differ among the three groups. The Colgate 360º showed less bristle wear and a better bristle tip morphology than the Oral B Indicator 35 toothbrush. However, use of either toothbrush did not decrease the bond strength of the orthodontic brackets. Therefore, patients undergoing orthodontic therapy can safely use either toothbrush. PMID:20877969

  11. A surface registration approach for video-based analysis of intraoperative brain surface deformations

    E-print Network

    Paris-Sud XI, Université de

    A surface registration approach for video-based analysis of intraoperative brain surface surface registration for video-based analysis of intraoperative brain deformations. This registration, we propose a new surface registration for video- based analysis of intraoperative brain deformations

  12. Devices based on surface plasmon interference filters

    NASA Technical Reports Server (NTRS)

    Wang, Yu (Inventor)

    2001-01-01

    Devices based on surface plasmon filters having at least one metal-dielectric interface to support surface plasmon waves. A multi-layer-coupled surface plasmon notch filter is provided to have more than two symmetric metal-dielectric interfaces coupled with one another to produce a transmission spectral window with desired spectral profile and bandwidth. Such notch filters can form various color filtering devices for color flat panel displays.

  13. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  14. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  15. 21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Bracket adhesive resin and tooth conditioner. 872...Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a...

  16. Surface Pretreatment Based On Dilute Hexafluorozirconic Acid

    Microsoft Academic Search

    Y. Zhai; Z. Zhao; G. S. Frankel; J. Zimmerman; T. Bryden; W. Fristad

    Two surface pretreatments based on dilute hexafluorozirconic acid (FZ) solution, a simple FZ and a modified FZ or MFZ, were studied as replacements for the phosphating process. The FZ conversion coatings were deposited on cold rolled steel (CRS) substrates by immersion treatment. AFM images reveal that the coating surface exhibited small features tens of nm in size and clusters of

  17. A tetrahedra-based stream surface algorithm

    Microsoft Academic Search

    Gerik Scheuermann; Tom Bobach; Hans Hagen; Karim Mahrous; Bernd Hamann; Kenneth I. Joy; Wolfgang Kollmann

    2001-01-01

    This paper presents a new algorithm for the calculation of stream surfaces for tetrahedral grids. It propagates the surface through the tetrahedra, one at a time, calculating the intersections with the tetrahedral faces. The method allows us to incorporate topological information from the cells, e.g., critical points. The calculations are based on barycentric coordinates, since this simplifies theory and algorithm.

  18. Microhardness of enamel adjacent to orthodontic brackets after CO2 laser irradiation and fluoride application.

    PubMed

    Stangler, Leonardo Pucci; Romano, Fábio Lourenço; Shirozaki, Mariana Umekita; Galo, Rodrigo; Afonso, Alessandra Marques Correa; Borsatto, Maria Cristina; Matsumoto, Mírian Aiko Nakane

    2013-01-01

    This study evaluated the effectiveness of carbon dioxide (CO2) laser combined or not with fluoride application on the surface microhardness of enamel adjacent to orthodontic brackets. Fifteen human molars were selected from which 30 enamel fragments measuring 4 mm2 were obtained. The fragments were embedded in PCV tubes with acrylic resin and prepared using water abrasive paper, felt disks and alumina. Orthodontic brackets cut in half were bonded to enamel and 3 microhardness readings were performed on the adjacent surface, as follows: initial, after cariogenic challenge and final. The specimens were divided into the following 3 groups (n=10): Group C: control, Group L: irradiated with CO2 laser, and Group FL: topical fluoride application and CO2 laser irradiation. After initial reading, the specimens were placed in a demineralizing solution for 32 h and the second reading was to verify if demineralization was uniform in all groups. After the treatments, the specimens were submitted to DES-RE cycling for 8 days followed by final surface microhardness reading. The data were analyzed statistically using ANOVA and Duncan test (?=0.05). At the final measurement Group FL obtained higher microhardness value than Groups C and L (p<0.05). Groups L and FL were statistically superior to Group C (p<0.05). Irradiation with CO2 laser around orthodontic brackets combined or not with topical fluoride application was effective to increase the surface microhardness of enamel. PMID:24474294

  19. Oral Comfort, Function and Hygienein Patients with Lingual Brackets

    Microsoft Academic Search

    Ariane Hohoff; Didier Fillion; Thomas Stamm; Gerhard Goder; Cristina Sauerland; Ulrike Ehmer

    2003-01-01

    Background: Oral comfort, speech, mastication and swallowing, as well as oral hygiene were to be evaluated in a prospective longitudinal study before and after insertion of lingual brackets. Patients and Method: 22 patients (five male, 17 female, mean age 34.7 years, SD 10.4) were enrolled in the study and filled in a standardized questionnaire directly before placement of lingual brackets

  20. RSRM nozzle actuator bracket/lug fracture mechanics qualification test

    NASA Astrophysics Data System (ADS)

    Kelley, Peggy

    1993-07-01

    This is the final report for the actuator bracket/lug fracture mechanics qualification test. The test plan (CTP-0071) outlined a two-phase test program designed to answer questions about the fracture criticality of the redesigned solid rocket motor (RSRM) nozzle actuator bracket. An analysis conducted using the NASA/FLAGRO fracture mechanics computer program indicated that the actuator bracket might be a fracture critical component. In the NASA/FLAGRO analysis, a simple lug model was used to represent the actuator bracket. It was calculated that the bracket would fracture if subjected to an actuator stall load in the presence of a 0.10 in. corner crack at the actuator attachment hole. The 0.10 in. crack size corresponds to the nondestructive inspection detectability limit for the actuator bracket. The inspection method used is the dye penetrant method. The actuator stall load (103,424 lb) is the maximum load which the actuator bracket is required to withstand during motor operation. This testing was designed to establish the accuracy of the analytical model and to directly determine whether the actuator bracket is capable of meeting fracture mechanics safe-life requirements.

  1. RSRM nozzle actuator bracket/lug fracture mechanics qualification test

    NASA Technical Reports Server (NTRS)

    Kelley, Peggy

    1993-01-01

    This is the final report for the actuator bracket/lug fracture mechanics qualification test. The test plan (CTP-0071) outlined a two-phase test program designed to answer questions about the fracture criticality of the redesigned solid rocket motor (RSRM) nozzle actuator bracket. An analysis conducted using the NASA/FLAGRO fracture mechanics computer program indicated that the actuator bracket might be a fracture critical component. In the NASA/FLAGRO analysis, a simple lug model was used to represent the actuator bracket. It was calculated that the bracket would fracture if subjected to an actuator stall load in the presence of a 0.10 in. corner crack at the actuator attachment hole. The 0.10 in. crack size corresponds to the nondestructive inspection detectability limit for the actuator bracket. The inspection method used is the dye penetrant method. The actuator stall load (103,424 lb) is the maximum load which the actuator bracket is required to withstand during motor operation. This testing was designed to establish the accuracy of the analytical model and to directly determine whether the actuator bracket is capable of meeting fracture mechanics safe-life requirements.

  2. Hydrodynamic chains and the classification of their Poisson brackets

    NASA Astrophysics Data System (ADS)

    Pavlov, Maxim V.

    2006-12-01

    Infinite component Poisson brackets of the Dubrovin-Novikov type [Sov. Math. Dokl. 27, 665-669 (1983)] are considered. The corresponding Jacobi identity is significantly simplified in the Liouville coordinates since the skew-symmetry condition is automatically satisfied. The concept of M Poisson bracket connected with hydrodynamic chains is introduced. Then the Jacobi identity is a nonlinear system of equations in partial derivatives which can be completely integrated. In such a case, a classification of infinite component Poisson brackets of the Dubrovin-Novikov type can be obtained. Two simplest examples, M =0 and M =1, are considered. Also infinite component Poisson brackets of the Ferapontov [Am. Math. Soc. Transl. 170, 38-58 (1995)] type can be simplified in the Liouville coordinates. The Jacobi identity for infinite component Poisson brackets of the Ferapontov-Mokhov type [Russ. Math. Surveys 45, 218-219 (1990)] is presented in the Liouville coordinates

  3. Photogrammetry with surface-based images.

    PubMed

    Batson, R M

    1969-07-01

    Stereoscopic pictures returned by surface-based imaging systems can be used to reconstruct the topography of landing sites on Mars and other planets. Large surface relief with respect to distance and the large scale variation inherent in surface-based pictures produce problems in stereoscopic measurement very different from those presented by high altitude photography. Optical-mechanical scanning systems, or facsimile cameras, facilitate accurate reconstruction of landing site topography because of the linearity of system photometric response and the accuracy with which image geometry can be measured. PMID:20072433

  4. Comparative Evaluation of Friction Resistance of Titanium, Stainless Steel, Ceramic and Ceramic with Metal Insert Brackets with Varying Dimensions of Stainless Steel Wire: An In vitro Multi-center Study

    PubMed Central

    Kumar, B Sunil; Miryala, Suresh; Kumar, K Kiran; Shameem, K; Regalla, Ravindra Reddy

    2014-01-01

    Background: The orthodontist seeks an archwire–bracket combination that has both good biocompatibility and low friction. Hence, the aim of this multicenter in vitro study was to evaluate and compare the frictional resistance generated between titanium (Ti), stainless steel (SS), ceramic and ceramic with metal insert (CMI) brackets with SS wires of varying dimensions in a specially designed apparatus. Materials and Methods: The material used in this study were Ti, SS, Ceramic and CMI with 0.018? slot manufactured with zero degree tip and ?7° torque premolar brackets (3M, Unitek) and SS wires of varying dimensions (0.016? round, 0.016 × 0.016? square, 0.016 × 0.022? rectangular and 0.017 × 0.025? rectangular) used. The frictional resistance was measured using Instron Universal testing machine (Model no. 4301). The specimen population in each center composed each of 160 brackets and wires. Differences among the all bracket/wire combinations were tested using (one-way) ANOVA, followed by the student Newman Keuls multiple comparisons of means ranking (at P < 0.05) for the determination of differences among the groups. Results: Ti bracket in combination with 0.017 × 0.025? SS rectangular wire produced significant force levels for an optimum orthodontic movement with least frictional resistance. Conclusion: Ti brackets have least resistance and rectangular wires produced significant force. These can be used to avoid hazards of Nickel. SS brackets revealed higher static frictional force values as the wire dimension increased and showed lower static friction than Ti brackets for all wires except the thicker wire. Our study recommends the preclusion of brackets with rough surface texture (Ti brackets) with SS ligature wire for ligating bracket and archwire are better to reduce friction. PMID:25395796

  5. Nonlaser-based 3D surface imaging

    SciTech Connect

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  6. Probability Bracket Notation and Probability Modeling

    E-print Network

    Wang, Xing M

    2009-01-01

    Inspired by the Dirac notation, a new set of symbols, the Probability Bracket Notation (PBN) is proposed for probability modeling. By applying PBN to discrete and continuous random variables, we show that PBN could play a similar role in probability spaces as the Dirac notation in Hilbert vector spaces. The time evolution of homogeneous Markov chains with discrete-time and continuous-time are discussed in PBN. Our system state p-kets are identified with the probability vectors, while our system state p-bra can be identified with the Doi state function or the Peliti standard bra. We also suggest that, by transforming from the Schrodinger picture to the Heisenberg picture, the time-dependence of a system p-ket of a homogeneous MC can be shifted to the observable as a stochastic process.

  7. Probability Bracket Notation and Probability Modeling

    E-print Network

    Xing M. Wang

    2009-09-07

    Inspired by the Dirac notation, a new set of symbols, the Probability Bracket Notation (PBN) is proposed for probability modeling. By applying PBN to discrete and continuous random variables, we show that PBN could play a similar role in probability spaces as the Dirac notation in Hilbert vector spaces. The time evolution of homogeneous Markov chains with discrete-time and continuous-time are discussed in PBN. Our system state p-kets are identified with the probability vectors, while our system state p-bra can be identified with the Doi state function or the Peliti standard bra. We also suggest that, by transforming from the Schrodinger picture to the Heisenberg picture, the time-dependence of a system p-ket of a homogeneous MC can be shifted to the observable as a stochastic process.

  8. Effect of silica coating on bond strength between a gold alloy and metal bracket bonded with chemically cured resin

    PubMed Central

    Ryu, Min-Ju; Lim, Sung-Hoon

    2014-01-01

    Objective The purpose of this study was to evaluate the effects of three different surface conditioning methods on the shear bond strength (SBS) of metal brackets bonded directly to gold alloy with chemically cured resin. Methods Two hundred ten type III gold alloy specimens were randomly divided into six groups according to the combination of three different surface conditioning methods (aluminum oxide sandblasting only, application of a metal primer after aluminum oxide sandblasting, silica coating and silanation) and thermocycling (with thermocycling, without thermocycling). After performing surface conditioning of specimens in accordance with each experimental condition, metal brackets were bonded to all specimens using a chemically cured resin. The SBS was measured at the moment of bracket debonding, and the resin remnants on the specimen surface were evaluated using the adhesive remnant index. Results Application of metal primer after aluminum oxide sandblasting yielded a higher bond strength than that with aluminum oxide sandblasting alone (p < 0.001), and silica coating and silanation yielded a higher bond strength than that with metal primer after aluminum oxide sandblasting (p < 0.001). There was no significant change in SBS after thermocycling in all groups. Conclusions With silica coating and silanation, clinically satisfactory bond strength can be attained when metal brackets are directly bonded to gold alloys using a chemically cured resin. PMID:24892023

  9. Helical surface reconstruction based on CMM

    NASA Astrophysics Data System (ADS)

    Pan, Zhikang; Zhu, Lianqing; Chen, Qingshan; Guo, Yangkuan

    2010-12-01

    The reconstruction of helical surface plays an important role in many engineering and scientific applications. This paper tends to establish an effective processing scheme of surface reconstruction of scatter 3D points, and make an in-depth exploration for the preprocessing technology of scatter points set and the algorithm of three-dimension model surface reconstruction. This paper has three main aspects: data acquisition, data preprocess and surface reconstruction. First, by comparing several measuring equipments, the screw parts are scanned via CMM (Coordinate Measuring Machine). Initial 3D point clouds are obtained by setting the scanning route according to the shape of the targets. Second, Using "3?" criteria point de-noising is applied to the initial data points. Then Heap Sort is used to sort these points, being convenient for saving data and reconstructing the surface. Third, this paper presents a surface reconstruction method based on triangulation algorithm. The triangular meshes are generated based on Delaunay triangulation technique in two dimensions. And Loop Subdivision is adopted in order to get manifold meshes. Finally the surface reconstruction of an involute worm and an Archimedes worm shows that this approach is feasible.

  10. Helical surface reconstruction based on CMM

    NASA Astrophysics Data System (ADS)

    Pan, Zhikang; Zhu, Lianqing; Chen, Qingshan; Guo, Yangkuan

    2011-05-01

    The reconstruction of helical surface plays an important role in many engineering and scientific applications. This paper tends to establish an effective processing scheme of surface reconstruction of scatter 3D points, and make an in-depth exploration for the preprocessing technology of scatter points set and the algorithm of three-dimension model surface reconstruction. This paper has three main aspects: data acquisition, data preprocess and surface reconstruction. First, by comparing several measuring equipments, the screw parts are scanned via CMM (Coordinate Measuring Machine). Initial 3D point clouds are obtained by setting the scanning route according to the shape of the targets. Second, Using "3?" criteria point de-noising is applied to the initial data points. Then Heap Sort is used to sort these points, being convenient for saving data and reconstructing the surface. Third, this paper presents a surface reconstruction method based on triangulation algorithm. The triangular meshes are generated based on Delaunay triangulation technique in two dimensions. And Loop Subdivision is adopted in order to get manifold meshes. Finally the surface reconstruction of an involute worm and an Archimedes worm shows that this approach is feasible.

  11. Enamel resistance to demineralization following Er:YAG laser etching for bonding orthodontic brackets

    PubMed Central

    Ahrari, Farzaneh; Poosti, Maryam; Motahari, Pourya

    2012-01-01

    Background: Several studies have shown that laser-etching of enamel for bonding orthodontic brackets could be an appropriate alternative for acid conditioning, since a potential advantage of laser could or might be caries prevention. This study compared enamel resistance to demineralization following etching with acid phosphoric or Er:YAG laser for bonding orthodontic brackets. Materials and Methods: Fifty sound human premolars were divided into two equal groups. In the first group, enamel was etched with 37% phosphoric acid for 15 seconds. In the second group, Er:YAG laser (wavelength, 2 940 nm; 300 mJ/pulse, 10 pulses per second, 10 seconds) was used for tooth conditioning. The teeth were subjected to 4-day PH-cycling process to induce caries-like lesions. The teeth were then sectioned and the surface area of the lesion was calculated in each microphotographs and expressed in pixel. The total surface of each specimen was 196 608 pixels. Results: Mean lesion areas were 7 171 and 7532 pixels for Laser-etched and Acid-etched groups, respectively. The two sample t-test showed that there was no significant difference in lesion area between the two groups (P = 0.914). Conclusion: Although Er:YAG laser seems promising for etching enamel before bonding orthodontic brackets, it does not reduce enamel demineralization when exposed to acid challenge. PMID:23162591

  12. Poisson brackets and clebsch representations for magnetohydrodynamics, multifluid plasmas, and elasticity

    Microsoft Academic Search

    Darryl D. Holm; Boris A. Kupershmidt

    1983-01-01

    Poisson brackets are constructed by the same mathematical procedure for three physical theories: ideal magnetohydrodynamics, multifluid plasmas, and elasticity. Each of these brackets is given a simple Lie-algebraic interpretation. Moreover, each bracket is induced to physical space by use of a canonical Poisson bracket in the space of Clebsch potentials, which are constructed for each physical theory by the standard

  13. Research highlights: surface-based microfluidic control.

    PubMed

    Adeyiga, Oladunni; Kahkeshani, Soroush; Paiè, Petra; Di Carlo, Dino

    2015-07-14

    Microfluidic systems are often dominated by their surfaces because of the high surface area to volume ratios in microchannel flows or drop-based systems. Here we highlight recent work on engineering and exploiting surface effects to control the formation and motion of microdrops. We highlight work using precisely microstructured wetting surfaces to repel all manner of liquids even when the liquid-air surface tension is low. In a second paper, selective capillary filling and draining is used to pattern liquid and cell-laden gels for 3D culture. A final paper making use of vapor-driven surface tension effects to drive the motion of drop ensembles is also examined, exploring a new mechanism for drop control - including motion and merging. Surface-driven motion and patterning has been a widely successful area in microfluidics (e.g. electrowetting or patterned self-assembled monolayers) and recent work is extending into new directions that, once well-understood, should enable new applications. PMID:26095691

  14. Surface modification of polypropylene based particle foams

    NASA Astrophysics Data System (ADS)

    Schreier, P.; Trassl, C.; Altstädt, V.

    2014-05-01

    This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

  15. Options for a lunar base surface architecture

    Microsoft Academic Search

    Barney B. Roberts

    1992-01-01

    The Planet Surface Systems Office at the NASA Johnson Space Center has participated in an analysis of the Space Exploration Initiative architectures described in the Synthesis Group report. This effort involves a Systems Engineering and Integration effort to define point designs for evolving lunar and Mars bases that support substantial science, exploration, and resource production objectives. The analysis addresses systems-level

  16. 24. PHOTOGRAPH OF FIRST FLOOR. NOTE BRACKETS ON CENTER COLUMN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. PHOTOGRAPH OF FIRST FLOOR. NOTE BRACKETS ON CENTER COLUMN WHERE BRASS STATUS GAGES WERE MOUNTED TO MONITOR STEAM AND WATER PRESSURES IN YARD MAINS. SEE PHOTO CA-2294-25. - Mare Island Naval Shipyard, Firehouse, Vallejo, Solano County, CA

  17. 21 CFR 872.5470 - Orthodontic plastic bracket.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...5470 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification....

  18. Detail of large, brick columns and bracket inside Electrical Shop ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of large, brick columns and bracket inside Electrical Shop - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Electrical Shop, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  19. 6. Detail of bracket supporting roof overhang on twostory warehouse. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Detail of bracket supporting roof overhang on two-story warehouse. - Central of Georgia Railway, Down Freight Warehouse, 233 West Broad Street (at rear of Red Building), Savannah, Chatham County, GA

  20. Detail of diagonal end post support bracket mounted to east ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of diagonal end post support bracket mounted to east face of track girder, east span. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA

  1. Analysis of Bracket Assembly for Portable Leak Detector Station

    SciTech Connect

    ZIADA, H.H.

    1999-08-19

    This Supporting Document Presents Structural and Stress Analysis of a Portable Leak Detector Station for Tank Farms. The results show that the bracket assembly meets the requirements for dead load and natural phenomena hazards loads (seismic and wind).

  2. Quantization with maximally degenerate Poisson brackets: The harmonic oscillator!

    E-print Network

    Y. Nutku

    2003-06-09

    Nambu's construction of multi-linear brackets for super-integrable systems can be thought of as degenerate Poisson brackets with a maximal set of Casimirs in their kernel. By introducing privileged coordinates in phase space these degenerate Poisson brackets are brought to the form of Heisenberg's equations. We propose a definition for constructing quantum operators for classical functions which enables us to turn the maximally degenerate Poisson brackets into operators. They pose a set of eigenvalue problems for a new state vector. The requirement of the single valuedness of this eigenfunction leads to quantization. The example of the harmonic oscillator is used to illustrate this general procedure for quantizing a class of maximally super-integrable systems.

  3. The bracket-hack package Christopher Roman Nerz

    E-print Network

    Ould Ahmedou, Mohameden

    The bracket-hack package Christopher Roman Nerz June 5, 2014 Abstract This small LATEX-package1 := and =: to be \\coloneqq (..=) and \\eqqcolon (=..), respectively. brackethack@phoenixes.de 1This package is a `dirty-hack

  4. Detail of southwest corner eave with brackets, stringer, and rafters ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of southwest corner eave with brackets, stringer, and rafters supporting exposed roof decking and tile roof, facing northwest. - Marine Barracks, Panama Canal, Officers' Quarters, 800' West of Bruja Road, Balboa, Former Panama Canal Zone, CZ

  5. The classification of nonsingular multidimensional Dubrovin-Novikov brackets

    Microsoft Academic Search

    O. I. Mokhov; L. D. Landau

    2008-01-01

    In this paper, the well-known Dubrovin-Novikov problem posed as long ago as in 1984 in connection with the Hamiltonian theory\\u000a of systems of hydrodynamic type, namely, the classification problem for multidimensional Poisson brackets of hydrodynamic\\u000a type, is solved. In contrast to the one-dimensional case, in the general case, a nondegenerate multidimensional Poisson bracket\\u000a of hydrodynamic type cannot be reduced to

  6. The effect of casein phosphopeptide amorphous calcium phosphate on the in vitro shear bond strength of orthodontic brackets

    PubMed Central

    Park, Sun-Youn; Cha, Jung-Yul; Kim, Kyoung-Nam

    2013-01-01

    Objective The purpose of this study was to evaluate the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on the shear bond strength (SBS) of brackets bonded to non-demineralized teeth with either phosphoric acid etching or self-etching primer. Methods Sixty human premolars were randomly assigned to 1 of 4 treatment groups (n = 15 each): phosphoric acid etching (group 1); self-etching primer (group 2); CPP-ACP for 2 weeks + phosphoric acid etching (group 3), and CPP-ACP for 2 weeks + self-etching primer (group 4). After bonding of the maxillary premolar metal brackets, specimens were subjected to shear forces in a testing machine. Scanning electron microscopy was used to observe etching patterns on the enamel surfaces of all teeth. A 2-way analysis of variance was used to test for effects of CPP-ACP and etching system on SBS. Results Significantly higher mean SBSs were observed in groups subjected to phosphoric acid etching (i.e., groups 1 and 3; p < 0.05). On the other hand, SBSs did not appear to be influenced by CPP-ACP (i.e., groups 3 and 4; p > 0.05). We observed a uniform and clear etched pattern on the enamel surface of the phosphoric acid etching groups. Conclusions CPP-ACP does not significantly affect the SBS of orthodontic brackets bonded to non-demineralized teeth, regardless of which adhesive method is used to bond the brackets. PMID:23504444

  7. Probability Bracket Notation: Probability Space, Conditional Expectation and Introductory Martingales

    E-print Network

    Xing M. Wang

    2009-10-15

    In this paper, we continue to explore the consistence and usability of Probability Bracket Notation (PBN) proposed in our previous articles. After a brief review of PBN with dimensional analysis, we investigate probability spaces in terms of PBN by introducing probability spaces associated with random variables (R.V) or associated with stochastic processes (S.P). Next, we express several important properties of conditional expectation (CE) and some their proofs in PBN. Then, we introduce martingales based on sequence of R.V or based on filtration in PBN. In the process, we see PBN can be used to investigate some probability problems, which otherwise might need explicit usage of Measure theory. Whenever applicable, we use dimensional analysis to validate our formulas and use graphs for visualization of concepts in PBN. We hope this study shows that PBN, stimulated by and adapted from Dirac notation in Quantum Mechanics (QM), may have the potential to be a useful tool in probability modeling, at least for those who are already familiar with Dirac notation in QM.

  8. Probability Bracket Notation: Probability Space, Conditional Expectation and Introductory Martingales

    E-print Network

    Wang, Xing M

    2007-01-01

    In this paper, we continue to explore the consistence and usability of Probability Bracket Notation (PBN) proposed in our previous articles. After a brief review of PBN with dimensional analysis, we investigate probability spaces in terms of PBN by introducing probability spaces associated with random variables (R.V) or associated with stochastic processes (S.P). Next, we express several important properties of conditional expectation (CE) and some their proofs in PBN. Then, we introduce martingales based on sequence of R.V or based on filtration in PBN. In the process, we see PBN can be used to investigate some probability problems, which otherwise might need explicit usage of Measure theory. Whenever applicable, we use dimensional analysis to validate our formulas and use graphs for visualization of concepts in PBN. We hope this study shows that PBN, stimulated by and adapted from Dirac notation in Quantum Mechanics (QM), may have the potential to be a useful tool in probability modeling, at least for those...

  9. Evaluation of Surface Fatigue Strength Based on Surface Temperature

    NASA Astrophysics Data System (ADS)

    Deng, Gang; Nakanishi, Tsutomu

    Surface temperature is considered to be an integrated index that is dependent on not only the load and the dimensions at the contact point but also the sliding velocity, rolling velocity, surface roughness, and lubrication conditions. Therefore, the surface durability of rollers and gears can be evaluated more exactly and simply by the use of surface temperature rather than Hertzian stress. In this research, surface temperatures of rollers under different rolling and sliding conditions are measured using a thermocouple. The effects of load P, mean velocity Vm and sliding velocity Vs on surface temperature are clarified. An experimental formula, which expresses the linear relationship between surface temperature and the P0.86Vs1.31Vm-0.83 value, is used to determine surface temperature. By comparing calculated and measured temperature on the tooth surface of a gear, this formula is confirmed to be applicable for gear tooth surface temperature calculation.

  10. Microleakage under orthodontic brackets bonded with different adhesive systems

    PubMed Central

    Alkis, Huseyin; Turkkahraman, Hakan; Adanir, Necdet

    2015-01-01

    Objective: This in vitro study aimed to compare the microleakage of orthodontic brackets between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival margins bonded with different adhesive systems. Materials and Methods: A total of 144 human maxillary premolar teeth extracted for orthodontic reasons was randomly divided into four groups. Each group was then further divided into three sub-groups. Three total-etching bonding systems (Transbond XT, Greengloo and Kurasper F), three one-step self-etching bonding systems (Transbond Plus SEP, Bond Force and Clearfil S3), three two-step self-etching bonding systems (Clearfil SE Bond, Clearfil Protectbond and Clearfil Liner Bond), and three self-adhesive resin cements (Maxcem Elite, Relyx U 100 and Clearfil SA Cement) were used to bond the brackets to the teeth. After bonding, all teeth were sealed with nail varnish and stained with 0.5% basic fuchsine for 24 h. All samples were sectioned and examined under a stereomicroscope to score for microleakage at the adhesive–enamel and adhesive–bracket interfaces from both occlusal and gingival margins. Statistical Analysis Used: Statistical analyses were performed with Kruskal–Wallis and Wilcoxon signed-rank tests. Results: The results indicate no statistically significant differences between the microleakage scores of the adhesives; microleakage was detected in all groups. Comparison of the average values of the microleakage scores in the enamel–adhesive and adhesive–bracket interfaces indicated statistically significant differences (P < 0.05). The amount of the microleakage was higher at the enamel–adhesive interface than at the bracket-adhesive interface. Conclusions: All of the brackets exhibited some amount of microleakage. This result means that microleakage does not depend on the type of adhesive used. PMID:25713494

  11. Comparison of the Debonding Characteristics of Conventional and New Debonding Instrument used for Ceramic, Composite and Metallic Brackets – An Invitro Study

    PubMed Central

    Gill, Vikas; Reddy, Y. N. N.; Sanadhya, Sudhanshu; Aapaliya, Pankaj; Sharma, Nidhi

    2014-01-01

    Background: Debonding procedure is time consuming and damaging to the enamel if performed with improper technique. Various debonding methods include: the conventional methods that use pliers or wrenches, an ultrasonic method, electrothermal devices, air pressure impulse devices, diamond burs to grind the brackets off the tooth surface and lasers. Among all these methods, using debonding pliers is most convenient and effective method but has been reported to cause damage to the teeth. Recently, a New Debonding Instrument designed specifically for ceramic and composite brackets has been introduced. As this is a new instrument, little information is available on efficacy of this instrument. The purpose of this study was to evaluate the debonding characteristics of both “the conventional debonding Pliers” and “the New debonding instrument” when removing ceramic, composite and metallic brackets. Materials and Methods: One Hundred Thirty eight extracted maxillary premolar teeth were collected and divided into two Groups: Group A and Group B (n = 69) respectively. They were further divided into 3 subGroups (n = 23) each according to the types of brackets to be bonded. In subGroups A1 and B1{stainless steel};A2 and B2{ceramic};A3 and B3{composite}adhesive precoated maxillary premolar brackets were used. Among them {ceramic and composite} adhesive pre-coated maxillary premolar brackets were bonded. All the teeth were etched using 37% phosphoric acid for 15 seconds and the brackets were bonded using Transbond XT primer. Brackets were debonded using Conventional Debonding Plier and New Debonding Instrument (Group B). After debonding, the enamel surface of each tooth was examined under stereo microscope (10X magnifications). Amodifiedadhesive remnant index (ARI) was used to quantify the amount of remaining adhesive on each tooth. Results: The observations demonstrate that the results of New Debonding Instrument for debonding of metal, ceramic and composite brackets were statistically significantly different (p = 0.04) and superior from the results of conventional debonding Pliers. Conclusion: The debonding efficiency of New Debonding Instrument is better than the debonding efficiency of Conventional Debonding Pliers for use of metal, ceramic and composite brackets respectively. PMID:25177639

  12. Bonded Bracket Assmebly for Frameless Solar Panels

    SciTech Connect

    Murray, Todd

    2013-01-30

    In February 2011 the US Department of Energy announced their new Sunshot Initiative. The Sunshot goal is to reduce the total cost of solar energy systems by about 75 percent before the end of the decade. The DOE estimated that a total installed cost of $1 per watt for photovoltaic systems would be equivalent to 6���¢/kilowatt hour (kWh) for energy available from the grid. The DOE also estimated that to meet the $1 per watt goal, PV module costs would need to be reduced to $.50 per watt, balance of systems costs would need to be reduced to $.40 per watt, and power electronic costs would need to reach $.10 per watt. To address the BOS balance of systems cost component of the $1 per watt goal, the DOE announced a funding opportunity called (BOS-X) Extreme Balance of System Hardware Cost Reductions. The DOE identified eight areas within the total BOS costs: 1) installation labor, 2) installation materials, 3) installation overhead and profit, 4) tracker, 5) permitting and commissioning, 6) site preparation, 7) land acquisition, 8) sales tax. The BOS-X funding announcement requested applications in four specific topics: Topic 1: Transformational Building Integrated Photovoltaic (BIPV) Modules Topic 2: Roof and Ground Mount Innovations Topic 3: Transformational Photovoltaic System Designs Topic 4: Development of New Wind Load Codes for PV Systems The application submitted by ARaymond Tinnerman reflected the requirements listed in Topic #2, Roof and Ground Mount Innovations. The goal of topic #2 was to develop technologies that would result in the extreme reduction of material and labor costs associated with applications that require physical connections and attachments to roof and ground mount structures. The topics researched in this project included component cost reduction, labor reduction, weight reduction, wiring innovations, and alternative material utilization. The project objectives included: 1) The development of an innovative quick snap bracket assembly that would be bonded to frameless PV modules for commercial rooftop installations. 2) The development of a composite pultruded rail to replace traditional racking materials. 3) In partnership with a roofing company, pilot the certification of a commercial roof to be solar panel compliant, eliminating the need for structural analysis and government oversight resulting in significantly decreased permitting costs. 4) Reduce the sum of all cost impacts in topic #2 from a baseline total of $2.05/watt to $.34/watt.

  13. Bracketed morality revisited: how do athletes behave in two contexts?

    PubMed

    Kavussanu, Maria; Boardley, Ian D; Sagar, Sam S; Ring, Christopher

    2013-10-01

    The concept of bracketed morality has received empirical support in several sport studies (e.g., Bredemeier & Shields, 1986a, 1986b). However, these studies have focused on moral reasoning. In this research, we examined bracketed morality with respect to moral behavior in sport and university contexts, in two studies. Male and female participants (Study 1: N = 331; Study 2: N = 372) completed questionnaires assessing prosocial and antisocial behavior toward teammates and opponents in sport and toward other students at university. Study 2 participants also completed measures of moral disengagement and goal orientation in both contexts. In most cases, behavior in sport was highly correlated with behavior at university. In addition, participants reported higher prosocial behavior toward teammates and higher antisocial behavior toward opponents in sport than toward other students at university. The effects of context on antisocial behavior were partially mediated by moral disengagement and ego orientation. Our findings extend the bracketed morality concept to prosocial and antisocial behavior. PMID:24197713

  14. Basics of Ternary Algebras and their underlying Nambu Brackets

    NASA Astrophysics Data System (ADS)

    Zachos, Cosmas K.

    2013-12-01

    Ternary algebras amount to closing systems of antisymmetrized trinomials of operators. The Filippov conditions (FI, which are not identities) for ternary algebras are contrasted to Bremner's identities dictated by associativity of operator products, and thus analogous to Jacobi identities. Maps of the known FI-compliant ternary algebras to underlying classical Nambu brackets are constructed, which then explain this compliance: FI-compliant ternary algebras are essentially classical Nambu brackets in disguise. In some cases involving infinite algebras, we show the classical limit may be obtained by a contraction of the quantal ternary algebra, and then explicitly realized through classical Nambu brackets. We illustrate this classical-contraction method on our Virasoro-Witt ternary algebra paradigm. The content of the talk is in the two references.

  15. Force loss in archwire-guided tooth movement of conventional and self-ligating brackets.

    PubMed

    Montasser, Mona A; El-Bialy, Tarek; Keilig, Ludger; Reimann, Susanne; Jäger, Andreas; Bourauel, Christoph

    2014-02-01

    This study aimed to investigate the differences in the force loss during simulated archwire-guided canine retraction between various conventional and self-ligating brackets. Three types of orthodontic brackets have been investigated experimentally using a biomechanical set-up: 1. conventional ligating brackets (Victory Series and Mini-Taurus), 2. self-ligating brackets (SmartClip: passive self-ligating bracket, and Time3 and SPEED: active self-ligating brackets), and 3. a conventional low-friction bracket (Synergy). All brackets had a nominal 0.022? slot size. The brackets were combined with three rectangular 0.019×0.025? archwires: 1. Remanium (stainless steel), 2. Nitinol SE (nickel-titanium alloy, NiTi), and 3. Beta III Titanium (titanium-molybdenum alloy). Stainless steel ligatures were used with the conventional brackets. Archwire-guided tooth movement was simulated over a retraction path of up to 4mm using a superelastic NiTi coil spring (force: 1 N). Force loss was lowest for the Victory Series and SmartClip brackets in combination with the steel guiding archwire (35 and 37.6 per cent, respectively) and highest for the SPEED and Mini-Taurus brackets in combination with the titanium wire (73.7 and 64.4 per cent, respectively). Force loss gradually increased by 10 per cent for each bracket type in combination with the different wires in the following sequence: stainless steel, Nitinol, and beta-titanium. Self-ligating brackets did not show improved performance compared with conventional brackets. There was no consistent pattern of force loss when comparing conventional and self-ligating brackets or passive and active self-ligating brackets. PMID:23382468

  16. Hand gesture recognition based on surface electromyography.

    PubMed

    Samadani, Ali-Akbar; Kulic, Dana

    2014-01-01

    Human hands are the most dexterous of human limbs and hand gestures play an important role in non-verbal communication. Underlying electromyograms associated with hand gestures provide a wealth of information based on which varying hand gestures can be recognized. This paper develops an inter-individual hand gesture recognition model based on Hidden Markov models that receives surface electromyography (sEMG) signals as inputs and predicts a corresponding hand gesture. The developed recognition model is tested with a dataset of 10 various hand gestures performed by 25 subjects in a leave-one-subject-out cross validation and an inter-individual recognition rate of 79% was achieved. The promising recognition rate demonstrates the efficacy of the proposed approach for discriminating between gesture-specific sEMG signals and could inform the design of sEMG-controlled prostheses and assistive devices. PMID:25570917

  17. Almost Poisson brackets for nonholonomic systems on Lie groups

    NASA Astrophysics Data System (ADS)

    Garcia-Naranjo, Luis Constantino

    We present a geometric construction of almost Poisson brackets for nonholonomic mechanical systems whose configuration space is a Lie group G. We study the so-called LL and LR systems where the kinetic energy defines a left invariant metric on G and the constraints are invariant with respect to left (respectively right) translation on G. For LL systems, the equations on the momentum phase space, T*G , can be left translated onto g *, the dual space of the Lie algebra g . We show that the reduced equations on g * can be cast in Poisson form with respect to an almost Poisson bracket that is obtained by projecting the standard Lie-Poisson bracket onto the constraint space. For LR systems we use ideas of semidirect product reduction to transfer the equations on T*G into the dual Lie algebra, s *, of a semidirect product. This provides a natural Lie algebraic setting for the equations of motion commonly found in the literature. We show that these equations can also be cast in Poisson form with respect to an almost Poisson bracket that is obtained by projecting the Lie-Poisson structure on s * onto a constraint submanifold. In both cases the constraint functions are Casimirs of the bracket and are satisfied automatically. Our construction is a natural generalization of the classical ideas of Lie-Poisson and semidirect product reduction to the nonholonomic case. It also sets a convenient stage for the study of Hamiltonization of certain nonholonomic systems. Our examples include the Suslov and the Veselova problems of constrained motion of a rigid body, and the Chaplygin sleigh. In addition we study the almost Poisson reduction of the Chaplygin sphere. We show that the bracket given by Borisov and Mamaev in [7] is obtained by reducing a nonstandard almost Poisson bracket that is obtained by projecting a non-canonical bivector onto the constraint submanifold using the Lagrange-D'Alembert principle. The examples that we treat show that it is possible to cast the reduced equations of motion of certain nonholonomic systems in Hamiltonian form (in the Poisson formulation) either by multiplication by a conformal factor, by the use of nonstandard brackets or simply by reduction methods.

  18. Measurement and Simulation of Distortion of a Steel Bracket Casting D. Galles and C. Beckermann

    E-print Network

    Beckermann, Christoph

    1 Measurement and Simulation of Distortion of a Steel Bracket Casting D. Galles and C Abstract Casting distortion, caused by core expansion, is measured during in situ experiments involving a cast steel bracket. Additional measurements of various bracket features are taken after shakeout

  19. Investigation of the Stability with Bracketing Design in Tablet Form

    Microsoft Academic Search

    Asuman Bozkir; Hacer Coskun Cetintas; Ongun Mehmet Saka

    2013-01-01

    EMA, FDA and ICH guidelines provide guidance to manufacturers of pharmaceutical products for planning and evaluating the stability tests. A full study design is discribed as a model in which samples for every combination of all design factors are tested at all time points. On the other hand matrix and bracket desings are known as a reduced design which can

  20. 43. Detail view of pivoting bracket used to move heavy ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    43. Detail view of pivoting bracket used to move heavy iron plate that covered trough next to iron notch when No. 2 Furnace was tapped. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  1. Analysis of Bracket Assembly for Diversion Box Leak Detector

    SciTech Connect

    ZIADA, H.H.

    1999-08-19

    This Supporting Document Presents Structural and Stress Analysis of a Bracket Assembly for the diversion box leak detectors related to the Cross Site Transfer Project. The results show that the assembly meets the requirements for dead load and natural phenomena hazards loads (seismic and wind).

  2. A computational fluid dynamic analysis of peri-bracket salivary flow influencing the microbial and periodontal parameters.

    PubMed

    Zhu, Ping; Lin, Han; Han, Yi; Lin, Yi; Xu, Yue; Zhang, Zhaoqiang

    2013-01-01

    Fixed vestibular appliances decrease the "self-cleansing" action of saliva and promote aggregation of dental plaque by disturbing the salivary flow field on tooth surfaces, leading to a higher prevalence of enamel demineralization and periodontal diseases. In the current study, we investigated the salivary dynamic characteristics of plaque retention and periodontal status around appliances during orthodontic treatment. By reconstructing lower central incisors and orthodontic appliances, we simulated saliva flow on the tooth surface and then characterized and quantified the salivary flow pattern surrounding the bracket and archwire. In parallel, we tested the total peri-bracket bacterial counts and periodontal status to assess interrelations. Our results demonstrate that orthodontic appliances disturb the salivary flow field on tooth surfaces and can lead to a decrease in salivary velocity and an increase in bacterial numbers. Local vortexes forming in the areas gingival to the bracket, together with the narrow space limitation, contributed to the periodontal inflammatory response. This study confirms that changes in salivary flow are an obvious predisposing factor for bacterial accumulation, and advances the ability to replicate, in vitro, the salivary characteristics of plaque retention and periodontal status around appliances during orthodontic treatment. PMID:23620815

  3. A Computational Fluid Dynamic Analysis of Peri-Bracket Salivary Flow Influencing the Microbial and Periodontal Parameters

    PubMed Central

    Zhu, Ping; Lin, Han; Han, Yi; Lin, Yi; Xu, Yue; Zhang, Zhaoqiang

    2013-01-01

    Fixed vestibular appliances decrease the “self-cleansing” action of saliva and promote aggregation of dental plaque by disturbing the salivary flow field on tooth surfaces, leading to a higher prevalence of enamel demineralization and periodontal diseases. In the current study, we investigated the salivary dynamic characteristics of plaque retention and periodontal status around appliances during orthodontic treatment. By reconstructing lower central incisors and orthodontic appliances, we simulated saliva flow on the tooth surface and then characterized and quantified the salivary flow pattern surrounding the bracket and archwire. In parallel, we tested the total peri-bracket bacterial counts and periodontal status to assess interrelations. Our results demonstrate that orthodontic appliances disturb the salivary flow field on tooth surfaces and can lead to a decrease in salivary velocity and an increase in bacterial numbers. Local vortexes forming in the areas gingival to the bracket, together with the narrow space limitation, contributed to the periodontal inflammatory response. This study confirms that changes in salivary flow are an obvious predisposing factor for bacterial accumulation, and advances the ability to replicate, in vitro, the salivary characteristics of plaque retention and periodontal status around appliances during orthodontic treatment. PMID:23620815

  4. Robust Toponym Resolution Based on Surface Statistics

    NASA Astrophysics Data System (ADS)

    Sano, Tomohisa; Nobesawa, Shiho Hoshi; Okamoto, Hiroyuki; Susuki, Hiroya; Matsubara, Masaki; Saito, Hiroaki

    Toponyms and other named entities are main issues in unknown word processing problem. Our purpose is to salvage unknown toponyms, not only for avoiding noises but also providing them information of area candidates to where they may belong. Most of previous toponym resolution methods were targeting disambiguation among area candidates, which is caused by the multiple existence of a toponym. These approaches were mostly based on gazetteers and contexts. When it comes to the documents which may contain toponyms worldwide, like newspaper articles, toponym resolution is not just an ambiguity resolution, but an area candidate selection from all the areas on Earth. Thus we propose an automatic toponym resolution method which enables to identify its area candidates based only on their surface statistics, in place of dictionary-lookup approaches. Our method combines two modules, area candidate reduction and area candidate examination which uses block-unit data, to obtain high accuracy without reducing recall rate. Our empirical result showed 85.54% precision rate, 91.92% recall rate and .89 F-measure value on average. This method is a flexible and robust approach for toponym resolution targeting unrestricted number of areas.

  5. Multiresolution Surface Modeling Based on Hierarchical Triangulation

    Microsoft Academic Search

    Marc Soucy; Denis Laurendeau

    1996-01-01

    This paper describes a sequential multiresolution surface modeling technique. The initial model consists in a surface triangulation resulting from the integration of a set of range views. Thereafter, a hierarchical triangulation algorithm iteratively removes vertices of the triangulation, always minimizing the retriangulation error. The equiangularity of the surface triangulation is optimized in 3-D space throughout the optimization process. Besides compressing

  6. GLDAS Land Surface Models based Aridity Indices

    NASA Astrophysics Data System (ADS)

    Pande, S.; Ghazanfari, S.

    2011-12-01

    Identification of dryland areas is crucial to guide policy aimed at intervening in water stressed areas and addressing its perennial livelihood or food insecurity. Aridity indices based on spatially relative soil moisture conditions such as NCEP aridity index allow cross comparison of dry conditions between sites. NCEP aridity index is based on the ratio of annual precipitation (supply) to annual potential evaporation (demand). Such an index ignores subannual scale competition between evaporation and drainage functions well as rainfall and temperature regimes. This determines partitioning of annual supply of precipitation into two competing (but met) evaporation and runoff demands. We here introduce aridity indices based on these additional considerations by using soil moisture time series for the past 3 decades from three Land Surface Models (LSM) models and compare it with NCEP index. We analyze global monthly soil moisture time series (385 months) at 1 x 1 degree spatial resolution as modeled by three GLDAS LSMs - VIC, MOSAIC and NOAH. The first eigen vector from Empirical Orthogonal Function (EOF) analysis, as it is the most dominant spatial template of global soil moisture conditions, is extracted. Frequency of nonexceedences of this dominant soil moisture mode for a location by other locations is calculated and is used as our proposed aridity index. An area is indexed drier (relative to other areas in the world) if its frequency of nonexceedence is lower. The EOF analysis reveals that their first eigen vector explains approximately 32%, 43% and 47% of variance explained by first 385 eigen vectors for VIC, MOSAIC and NOAH respectively. The temporal coefficients associated with it for all three LSMS show seasonality with a jump in trend around the year 1999 for NOAH and MOSAIC. The VIC aridity index displays a pattern most closely resembling that of NCEP though all LSM based indices isolate dominant dryland areas. However, all three LSMs identify some parts of south central Africa, southeast United States and eastern India as drier than NCEP classification. NOAH and MOSAIC indentify parts of Western Africa drier than the other two classifications, while NOAH and VIC indentify parts of central India as wetter than the other two classifications.

  7. Shape-based Diffeomorphic Registration on Hippocampal Surfaces Using Beltrami

    E-print Network

    Shape-based Diffeomorphic Registration on Hippocampal Surfaces Using Beltrami Holomorphic Flow. In our algorithm, we first propose a complete shape index using the Beltrami coefficient and curvatures. We propose a simple representation of surface diffeomorphisms using Beltrami coefficients, which

  8. A comparison of self-ligating and conventional orthodontic bracket systems.

    PubMed

    Read-Ward, G E; Jones, S P; Davies, E H

    1997-11-01

    This ex-vivo study compared the static frictional resistance of three self-ligating brackets with a conventional steel-ligated Ultratrimm bracket. The effects of archwire size (0.020, 0.019 x 0.025 and 0.021 x 0.025-inch), bracket/archwire angulation (0, 5 and 10 degrees) and the presence of unstimulated human saliva were investigated. The study demonstrated that both increases in wire size and bracket/archwire angulation resulted in increased static frictional resistance for all bracket types tested, with the presence of saliva having an inconsistent effect. Mobil-Lock Variable-Slot had the least friction for all wires for 0 degree angulation. However, with the introduction of angulation, the values were comparable to those of the other brackets. Activa brackets had the second lowest frictional resistance, although high values were found with 0.019 x 0.025-inch wires. SPEED brackets demonstrated low forces with round wires, although with rectangular wires or in the presence of angulation, friction was greatly increased. Ultratrimm brackets produced large individual variation, confirming the difficulty in standardizing ligation force, although under certain conditions, significantly larger frictional forces were observed. In conclusion, self-ligating brackets showed reduced frictional resistance in comparison to steel ligated brackets only under certain conditions. PMID:9459030

  9. Adherence of Streptococcus mutans and Candida albicans to different bracket materials

    PubMed Central

    Rammohan, Shrinivaasan Nambi; Juvvadi, Shubhaker Rao; Gandikota, Chandra Sekhar; Challa, Padmalatha; Manne, Ranjit; Mathur, Anirudh

    2012-01-01

    Objective: To quantify the adherence of Streptococcus mutans and Candida albicans on brackets made of stainless steel, plastic, ceramic, titanium, and gold, and to evaluate the various sites of adherence of these microorganisms with scanning electron microscopy (SEM). Materials and Methods: Brackets made of stainless steel, plastic, ceramic, titanium, and gold were used. The adherence of S. mutans and C. albicans were studied. The brackets were placed in flat-bottomed vials containing basal medium with 20% sucrose added; the flasks were inoculated with each of the microbial suspensions. The samples were incubated at 37°C for 48 h, after which the brackets were removed. The cells adhering to the glass were counted and the brackets were studied with SEM. Results: When evaluated together, the adherence of S. mutans and C. albicans was increased in the ceramic bracket group. When evaluated separately, metallic brackets had increased number of colony-forming units (CFUs) of S. mutans and the use of titanium brackets increased the CFUs of C. albicans. SEM demonstrated that the adherence of S. mutans and C. albicans together varied according to the bracket materials, with ceramic having the greatest and stainless steel having the least adherence. Conclusions: Oral hygiene may be of greater concern with esthetic brackets since this study shows that microbial adhesion is greater with these brackets. PMID:23066254

  10. Options for a lunar base surface architecture

    NASA Astrophysics Data System (ADS)

    Roberts, Barney B.

    1992-02-01

    The Planet Surface Systems Office at the NASA Johnson Space Center has participated in an analysis of the Space Exploration Initiative architectures described in the Synthesis Group report. This effort involves a Systems Engineering and Integration effort to define point designs for evolving lunar and Mars bases that support substantial science, exploration, and resource production objectives. The analysis addresses systems-level designs; element requirements and conceptual designs; assessments of precursor and technology needs; and overall programmatics and schedules. This paper focuses on the results of the study of the Space Resource Utilization Architecture. This architecture develops the capability to extract useful materials from the indigenous resources of the Moon and Mars. On the Moon, a substantial infrastructure is emplaced which can support a crew of up to twelve. Two major process lines are developed: one produces oxygen, ceramics, and metals; the other produces hydrogen, helium, and other volatiles. The Moon is also used for a simulation of a Mars mission. Significant science capabilities are established in conjunction with resource development. Exploration includes remote global surveys and piloted sorties of local and regional areas. Science accommodations include planetary science, astronomy, and biomedical research. Greenhouses are established to provide a substantial amount of food needs.

  11. SHEAR BOND STRENGTH OF METALLIC BRACKETS PHOTO-ACTIVATED WITH LIGHT-EMITTING DIODE (LED) AT DIFFERENT EXPOSURE TIMES

    PubMed Central

    Rêgo, Emanuel Braga; Romano, Fábio Lourenço

    2007-01-01

    The purpose of this study was to compare the shear bond strength of orthodontic metallic brackets photo-activated with two different light-curing sources at different exposure times: halogen light (XL 1500, 3M ESPE) and LED light (Ortholux, 3M Unitek). Sixty bovine permanent lower incisors were inserted into PVC tubes containing plaster. The buccal surfaces were cleaned with pumice and water, and then etched with 37% phosphoric acid gel. The XT Primer bonding agent (3M Unitek) was applied to the enamel surfaces and the metallic pre-coated brackets (Transbond APC II system, 3M Unitek) were attached to upper central incisors. The teeth were randomly divided into four groups (n=15). In Group I (Control), halogen light was used for 40 seconds, while in Groups II, III, and IV were light-cured with LED light unit for 40, 10, and 5 seconds, respectively. The teeth were stored in distilled water at 37°C for 24 hours. The brackets were submitted to shear bond strength test in universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Shear bond strength means (MPa) were 4.87 for Group I; 5.89 for Group II; 4.83 for Group III, and 4.39 for Group IV. Tukey's test detected no statistically significant differences among the groups regarding the shear bond strength (p>0.05). Neither of the types of light-curing sources or exposure times influenced the shear bond strength of metallic brackets. PMID:19089170

  12. Characterisation of surface wettability based on nanoparticles.

    PubMed

    Gao, Nan; Yan, Yuying

    2012-04-01

    Nanoparticles are becoming frequently used in the research area of creating functional surfaces because they can be more versatile than just making dimensions smaller. Particularly, a variety of nanoparticles have been applied for the construction of superhydrophobic and superhydrophilic surfaces with micro- and nano-scaled structures. As nanoparticles can also be fashioned and modified, their effects will be of great importance to the formed surface structures. In the present paper, we review the recent research progress in the utilization of nanoparticles to form extremely wettable/non-wettable surface structures and their influence on surface wettability. This report manifests an apparent inclination of nanoparticle structured surfaces using the multidisciplinary approaches, from the viewpoint of engineer/scientist. Therefore, the typical methodologies with regard to the use of nanoparticles, including the preparation and functionalisation processes, for the realization of surface wettabilities are discussed in this work. The discussions also represent some of the size-determined phenomena that are related to wettable/non-wettable surfaces. This Review thus provides an insight into the connection between nanoparticles and surface wettability. PMID:22392411

  13. Multivariate Tensor-based Brain Anatomical Surface Morphometry via Holomorphic

    E-print Network

    Wang, Yalin

    Multivariate Tensor-based Brain Anatomical Surface Morphometry via Holomorphic One-Forms Yalin Wang Introduction Surface-based methods have been extensively used to study structural features of the brain images to infer local differences in brain volume or shape. Tensor-based morphometry (TBM) [3] tends

  14. Efficiency in bracket bonding with the use of pretreatment methods to tooth enamel before acid etching: sodium hypochlorite vs. hydrogen peroxide techniques.

    PubMed

    Rivera-Prado, Hermann; Moyaho-Bernal, Ángeles; Andrade-Torres, Alejandro; Franco-Romero, Guillermo; Montiel-Jarquín, Álvaro; Mendoza-Pinto, Claudia; García-Cano, Eugenio; Hernández-Ruíz, Ana K

    2015-04-01

    Bond failures are produced by the existence of biofilm on the tooth surface. Because biofilm is impermeable, it prevents contact in many areas, reducing the etching effect which selectively dissolves calcified tissues but does not seem to eliminate biofilm from the tooth surface, and thus the bond between the tooth and the bracket is not strong enough. The aim of this study is to compare bracket bonding efficiency with two dental surface pretreatments: sodium hypochlorite vs. hydrogen peroxide techniques. This was a cross-sectional, comparative, in vitro study. Seventy-five premolars extracted for orthodontic purposes were evaluated. They were divided into three groups of 25 teeth and assigned randomly toone of the pretreatment techniques (5.25%sodium hypochlorite or 3.5% hydrogen peroxide) or to a control group. The most efficient pretreatment technique for bonding to brackets was sodium hypochlorite, with an average of 17.15 (kg/F). Significant differences were observed between groups (p=0.0001). The post hoc bond strength test showed statistically significant differences between the sodium hypochlorite technique and the control group (p=0.0001). The sodium hypochlorite technique improves bracket adhesion to tooth enamel. PMID:25950167

  15. Effects of ultrasonic instrumentation with different scaler-tip angulations on the shear bond strength and bond failure mode of metallic orthodontic brackets

    PubMed Central

    Incerti Parenti, Serena; Ippolito, Daniela Rit; Gatto, Maria Rosari; Luigi, Checchi

    2014-01-01

    Objective To evaluate the effects of ultrasonic instrumentation with different scaler-tip angulations on the shear bond strength (SBS) and bond failure mode of metallic orthodontic brackets. Methods Adhesive pre-coated metallic brackets were bonded to 72 extracted human premolars embedded in autopolymerizing acrylic resin. The teeth were randomly divided into 3 groups (n = 24 each) to undergo no treatment (control group) or ultrasonic instrumentation with a scaler-tip angulation of 45° (45°-angulation group) or 0° (0°-angulation group). SBS was tested in a universal testing machine, and adhesive remnant index (ARI) scores were recorded. The Kruskal-Wallis test and Mann-Whitney U-test were used for statistical analysis. Results The control group had a significantly higher mean SBS value than the treated groups, which showed no significant differences in their mean SBS values. The ARI scores were not significantly different among the groups. Conclusions Ultrasonic instrumentation around the bracket base reduces the SBS of metallic orthodontic brackets, emphasizing the need for caution during professional oral hygiene procedures in orthodontic patients. The scaler-tip angulation does not influence the SBS reduction and bond failure mode of such brackets. PMID:24511515

  16. Comparative Evaluation of Shear Bond Strength of Orthodontic Brackets on Pretreatment with CPPACP, Fluor Protector and Phosflur: An In-vitro Study

    PubMed Central

    2014-01-01

    Objective: The purpose of this study is to evaluate bond strength, bracket tooth interface of Orthodontic brackets that are bonded for fixed Orthodontic treatment procedure on pretreatment with CPPACP, Fluor Protector and Phosflur. The goal is to assess the adhesive remnants following application of these remineralizing agents using Adhesive Remnant Index. Materials and Methods: Two hundred freshly extracted premolar teeth each divided into Control, CPP-ACP, Fluor Protector and Phosflur. Teeth were pretreated with these agents prior to bonding procedure. Shear Bond Strength was tested using a Universal Testing Machine. A jig was attached to upper jaw of the machine. The acrylic block containing the embedded teeth was secured in the lower jaw of the machine such that the bracket base of the teeth parallel the direction of the shear force at a crosshead speed of 1 mm/minute until bracket failure. The force required to dislodge the bracket was recorded. Results: Mean Shear bond strength value is highest for Phosflur (15.3658 ± 2.4546 ) followed by Fluor Protector , CPP-ACP and lowest for Control (7.0462 ± 0.8838 MPa). Conclusion: Phosflur, Fluor protector,CPP-ACP have comparable Shear bond strength values in comparison to control. PMID:24995233

  17. Carbon nanotube-based robust steamphobic surfaces.

    PubMed

    Badge, Ila; Sethi, Sunny; Dhinojwala, Ali

    2011-12-20

    The wetting behavior of a surface under steam condensation depends on its intrinsic wettability and micrometer or nanoscale surface roughness. A typical superhydrophobic surface may not be suitable as a steamphobic surface because of the nucleation and growth of water inside the valleys and thus the failure to form an air-liquid-solid composite interface. Here, we present the results of steam condensation on chemically modified nanostructured carbon nanotube (CNT) mats. We used a plasma-enhanced chemical vapor deposition (PECVD) process to modify the intrinsic wettability of nanostructured CNT mats. The combination of low surface energy achieved by PECVD and the nanoroughness of the surface provides a mechanism to retain the superhydrophobicity of the CNT mats under steam condensation. The ability to withstand steam temperature and pressure for as long as 10 h implies the remarkably improved stability of the superhydrophobic state of the surface. The thermodynamic calculations carried out using a unit cell model clearly explain the steamphobic wetting behavior of the surface. PMID:22087571

  18. Green-Schwarz mechanism and $?'$-deformed Courant brackets

    E-print Network

    Olaf Hohm; Barton Zwiebach

    2014-08-06

    We establish that the unusual two-form gauge transformations needed in the Green-Schwarz anomaly cancellation mechanism fit naturally into an $\\alpha'$-deformed generalized geometry. The algebra of gauge transformations is a consistent deformation of the Courant bracket and features a nontrivial modification of the diffeomorphism group. This extension of generalized geometry emerged from a `doubled $\\alpha'$-geometry', which provides a construction of exactly gauge and T-duality invariant $\\alpha'$ corrections to the effective action.

  19. Direct Reduction to Talmi Integrals Without Use of Transformation Brackets

    Microsoft Academic Search

    R. H. Richardson; J. Shapiro; F. B. Malik

    1971-01-01

    The two-body shell-model matrix elements for central and tensor forces can be expanded as linear combinations of Talmi integrals. A closed form, which does not involve vector-coupling coefficients or transformation brackets, is obtained for the coefficients appearing in this expansion. For the case that all the oscillator constants are the same, the result is simple enough to allow tabulation. A

  20. 12. FLOOR BEAMS, BRACKETS, STRINGERS. (Also includes a schedule of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. FLOOR BEAMS, BRACKETS, STRINGERS. (Also includes a schedule of parts.) American Bridge Company, Ambridge Plant No. 5, sheet no. 2, dated April 2, 1928 (revised 4-24-28), order no. F5073. For U.S. Steel Products Company, Pacific Coast Depot, order no. SF578. For Southern Pacific Company, order no. 8873-P-28746. Scale 1/4 inch to one foot. - Napa River Railroad Bridge, Spanning Napa River, east of Soscol Avenue, Napa, Napa County, CA

  1. Computational Surface Flattening: A Voxel-Based Approach

    E-print Network

    Kimmel, Ron

    of this technology is the 3D photography of artifacts and Member, IEEE, and Ron Kimmel AbstractÐA voxel-based method for flattening a surface in 3D space into 2D of mapping a surface in 3D space into 2D. Given a digital representation of a surface in 3D, we wish to map

  2. Physics-Based Approaches to Modeling Surface Color Perception

    E-print Network

    Maloney, Laurence T.

    19 Physics-Based Approaches to Modeling Surface Color Perception Laurence T. Maloney The diversity) Introduction Surface Color Perception. The study of surface color perception is a proper subset of the study of color perception, and one way to highlight the differ- ence between them is to consider the effective

  3. FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS

    E-print Network

    Wickerhauser, M. Victor

    FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS Peter Fogh Odgaard ,1 Jakob. However, there are still problems with playing Compact Discs related to surface faults like scratches for handling surface faults which disturbs the position measurement and still react sufficiently against normal

  4. Surface characterization based on optical phase shifting interferometry

    DOEpatents

    Mello, Michael (Pasadena, CA), Rosakis; Ares J. (Altadena, CA)

    2011-08-02

    Apparatus, techniques and systems for implementing an optical interferometer to measure surfaces, including mapping of instantaneous curvature or in-plane and out-of-plane displacement field gradients of a sample surface based on obtaining and processing four optical interferograms from a common optical reflected beam from the sample surface that are relatively separated in phase by .pi./2.

  5. Experience With Bayesian Image Based Surface Modeling

    NASA Technical Reports Server (NTRS)

    Stutz, John C.

    2005-01-01

    Bayesian surface modeling from images requires modeling both the surface and the image generation process, in order to optimize the models by comparing actual and generated images. Thus it differs greatly, both conceptually and in computational difficulty, from conventional stereo surface recovery techniques. But it offers the possibility of using any number of images, taken under quite different conditions, and by different instruments that provide independent and often complementary information, to generate a single surface model that fuses all available information. I describe an implemented system, with a brief introduction to the underlying mathematical models and the compromises made for computational efficiency. I describe successes and failures achieved on actual imagery, where we went wrong and what we did right, and how our approach could be improved. Lastly I discuss how the same approach can be extended to distinct types of instruments, to achieve true sensor fusion.

  6. Coated Rectangular Composite Archwires: A Comparison Of Self-Ligating And Conventional Bracket Systems During Sliding Mechanics

    NASA Astrophysics Data System (ADS)

    Woods, David Keith

    The purpose of this study was to analyze the resistance to sliding of coated rectangular fiber reinforced composite archwires using various brackets systems and second-order bracket angulations. Resistance to sliding was investigated for eight bracket systems: six self-ligating brackets (four passive and two passive-active) and two conventional brackets. A rectangular fiber reinforced composite archwire of 0.019 x 0.025-in dimension from BiomersRTM SimpliClear was drawn through a three-bracket model system at ten millimeters per minute for 2.5 millimeters. For each bracket, the resistance to sliding was measured at four bracket angulations (0°, 2.5°, 5°, and 10°) in a dry state at room temperature. The fiber reinforced composite archwire produced the lowest sliding resistance with the passive self-ligating bracket system (Damon DQ) at each bracket angulation tested. Overall, self-ligating bracket systems generated lower sliding resistance than conventionally ligated systems, and one passive/active self-ligating bracket system (In-Ovation-R). There was a significant increase in resistance to sliding as bracket angulation increased for all bracket systems tested. Microscopic analysis revealed increased perforation of the archwire coating material as bracket angulations were increased. Our findings show that the rectangular fiber reinforced composite archwire may be acceptable for sliding mechanics during the intermediate stages of orthodontic tooth movement, however more long-term studies are needed.

  7. Ricci Flow-based Spherical Parameterization and Surface Registration

    PubMed Central

    Chen, X.; He, H.; Zou, G.; Zhang, X.; Gu, X.; Hua, J.

    2013-01-01

    This paper presents an improved Euclidean Ricci flow method for spherical parameterization. We subsequently invent a scale space processing built upon Ricci energy to extract robust surface features for accurate surface registration. Since our method is based on the proposed Euclidean Ricci flow, it inherits the properties of Ricci flow such as conformality, robustness and intrinsicalness, facilitating efficient and effective surface mapping. Compared with other surface registration methods using curvature or sulci pattern, our method demonstrates a significant improvement for surface registration. In addition, Ricci energy can capture local differences for surface analysis as shown in the experiments and applications. PMID:24019739

  8. Comparison of Shear Bond Strength of Orthodontic Brackets Bonded to Enamel Prepared By Er:YAG Laser and Conventional Acid-Etching

    PubMed Central

    Hosseini, M.H.; Namvar, F.; Chalipa, J.; Saber, K.; Chiniforush, N.; Sarmadi, S.; Mirhashemi, A.H.

    2012-01-01

    Introduction: The purpose of this study was to compare shear bond strength (SBS) of orthodontic brackets bonded to enamel prepared by Er:YAG laser with two different powers and conventional acid-etching. Materials and Methods: Forty-five human premolars extracted for orthodontic purposes were randomly assigned to three groups based on conditioning method: Group 1- conventional etching with 37% phosphoric acid; Group 2- irradiation with Er:YAG laser at 1 W; and Group 3- irradiation with Er:YAG laser at 1.5 W. Metal brackets were bonded on prepared enamel using a light-cured composite. All groups were subjected to thermocycling process. Then, the specimens mounted in auto-cure acryle and shear bond strength were measured using a universal testing machine with a crosshead speed of 0.5 mm per second. After debonding, the amount of resin remaining on the teeth was determined using the adhesive remnant index (ARI) scored 1 to 5. One-way analysis of variance was used to compare shear bond strengths and the Kruskal-Wallis test was performed to evaluate differences in the ARI for different etching types. Results: The mean and standard deviation of conventional acid-etch group, 1W laser group and 1.5W laser group was 3.82 ± 1.16, 6.97 ± 3.64 and 6.93 ± 4.87, respectively. Conclusion: The mean SBS obtained with an Er:YAG laser operated at 1W or 1.5W is approximately similar to that of conventional etching. However, the high variability of values in bond strength of irradiated enamel should be considered to find the appropriate parameters for applying Er:YAG laser as a favorable alternative for surface conditioning. PMID:22924098

  9. Ion Beam Analysis Of Silicon-Based Surfaces And Correlation With Surface Energy Measurements

    SciTech Connect

    Xing Qian; Herbots, N.; Hart, M.; Bradley, J. D.; Wilkens, B. J.; Sell, D. A.; Culbertson, R. J.; Whaley, S. D. [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States); Sell, Clive H.; Kwong, Henry Mark Jr. [Associated Retina Consultants, 7600 N 15th Street, Suite 155, Phoenix, AZ 85020 (United States)

    2011-06-01

    The water affinity of Si-based surfaces is quantified by contact angle measurement and surface free energy to explain hydrophobic or hydrophilic behavior of silicone, silicates, and silicon surfaces. Surface defects such as dangling bonds, surface free energy including Lewis acid-base and Lifshitz-van der Waals components are discussed. Water nucleation and condensation is further explained by surface topography. Tapping mode atomic force microscopy (TMAFM) provides statistical analysis of the topography of these Si-based surfaces. The correlation of the above two characteristics describes the behavior of water condensation at Si-based surfaces. Surface root mean square roughness increasing from several A ring to several nm is found to provide nucleation sites that expedite water condensation visibly for silica and silicone. Hydrophilic surfaces have a condensation pattern that forms puddles of water while hydrophobic surfaces form water beads. Polymer adsorption on these surfaces alters the water affinity as well as the surface topography, and therefore controls condensation on Si-based surfaces including silicone intraocular lens (IOL). The polymer film is characterized by Rutherford backscattering spectrometry (RBS) in conjunction with 4.265 MeV {sup 12}C({alpha}, {alpha}){sup 12}C, 3.045 MeV {sup 16}O({alpha},{alpha}){sup 16}O nuclear resonance scattering (NRS), and 2.8 MeV elastic recoil detection (ERD) of hydrogen for high resolution composition and areal density measurements. The areal density of hydroxypropyl methylcellulose (HPMC) film ranges from 10{sup 18} atom/cm{sup 2} to 10{sup 19} atom/cm{sup 2} gives the silica or silicone surface a roughness of several A ring and a wavelength of 0.16{+-}0.02 {mu}m, and prevents fogging by forming a complete wetting layer during water condensation.

  10. Ion Beam Analysis Of Silicon-Based Surfaces And Correlation With Surface Energy Measurements

    NASA Astrophysics Data System (ADS)

    Xing, Qian; Herbots, N.; Hart, M.; Bradley, J. D.; Wilkens, B. J.; Sell, D. A.; Sell, Clive H.; Kwong, Henry Mark; Culbertson, R. J.; Whaley, S. D.

    2011-06-01

    The water affinity of Si-based surfaces is quantified by contact angle measurement and surface free energy to explain hydrophobic or hydrophilic behavior of silicone, silicates, and silicon surfaces. Surface defects such as dangling bonds, surface free energy including Lewis acid-base and Lifshitz-van der Waals components are discussed. Water nucleation and condensation is further explained by surface topography. Tapping mode atomic force microscopy (TMAFM) provides statistical analysis of the topography of these Si-based surfaces. The correlation of the above two characteristics describes the behavior of water condensation at Si-based surfaces. Surface root mean square roughness increasing from several Å to several nm is found to provide nucleation sites that expedite water condensation visibly for silica and silicone. Hydrophilic surfaces have a condensation pattern that forms puddles of water while hydrophobic surfaces form water beads. Polymer adsorption on these surfaces alters the water affinity as well as the surface topography, and therefore controls condensation on Si-based surfaces including silicone intraocular lens (IOL). The polymer film is characterized by Rutherford backscattering spectrometry (RBS) in conjunction with 4.265 MeV 12C(?, ?)12C, 3.045 MeV 16O(?,?)16O nuclear resonance scattering (NRS), and 2.8 MeV elastic recoil detection (ERD) of hydrogen for high resolution composition and areal density measurements. The areal density of hydroxypropyl methylcellulose (HPMC) film ranges from 1018 atom/cm2 to 1019 atom/cm2 gives the silica or silicone surface a roughness of several Å and a wavelength of 0.16±0.02 ?m, and prevents fogging by forming a complete wetting layer during water condensation.

  11. Research Article Decontamination of Surfaces Exposed to Carbon-Based

    E-print Network

    Vaziri, Ashkan

    Research Article Decontamination of Surfaces Exposed to Carbon-Based Nanotubes and Nanomaterials nanomaterial-specific decontamination guidelines. In this paper, we propose and investigate a potential method for surface decontamination of carbon-based nanomaterials using solvent cleaning and wipes. The results show

  12. First-Principles-Based Surface Phase Diagram of Fully Relaxed Binary Alloy Surfaces

    Microsoft Academic Search

    O. Wieckhorst; S. Müller; L. Hammer; K. Heinz

    2004-01-01

    The combination of density-functional theory (DFT) calculations of geometrically fully relaxed binary alloy surfaces with concepts from statistical physics is applied to construct a DFT-based phase diagram for a binary alloy surface. As a first example, we studied the appearance of Co antisite atoms at CoAl(100) surfaces. The structural parameters as multilayer relaxations, surface buckling, lateral order, and segregation profile

  13. Local surface orientation analysis based on reflection estimation

    NASA Astrophysics Data System (ADS)

    Lu, Qinglin; Laligant, Olivier; Fauvet, Eric; Zakharova, Anatasia

    2015-04-01

    In this paper, we propose a novel reflection based method to estimate the local orientation of a specular surface. For a calibrated scene with a fixed light band, the band is reflected by the surface to the image plane of a camera. Then the local geometry between the surface and reflected band is estimated. Firstly, in order to find the relationship relying the object position, the object surface orientation and the band reflection, we study the fundamental theory of the geometry between a specular mirror surface and a band source. Then we extend our approach to the spherical surface with arbitrary curvature. Experiments are conducted with mirror surface and spherical surface. Results show that our method is able to obtain the local surface orientation merely by measuring the displacement and the form of the reflection.

  14. Evaluation of shear bond strength of orthodontic brackets bonded with Er-YAG laser etching

    PubMed Central

    Raji, S. Hamid; Birang, Reza; Majdzade, Fateme; Ghorbanipour, Reza

    2012-01-01

    Background: Based on contradictory findings concerning the use of lasers for enamel etching, the purpose of this study was to investigate the shear bond strength of teeth prepared for bonding with Er-YAG laser etching and compare them with phosphoric acid etching. Materials and Methods: In this in vitro study forty – eight premolars, extracted for orthodontic purposes were randomly divided in to three groups. Thirty-two teeth were exposed to laser energy for 25 s: 16 teeth at 100 mj setting and 16 teeth at 150 mj setting. Sixteen teeth were etched with 37% phosphoric acid. The shear bond strength of bonded brackets with the Transbond XT adhesive system was measured with the Zwick testing machine. Descriptive statistics, Kolmogorov–Smirnov test, of homogeneity of variances, one- way analysis of variances and Tukey's test and Kruskal Wallis were used to analyze the data. Results: The mean shear bond strength of the teeth lased with 150 mj was 12.26 ± 4.76 MPa, which was not significantly different from the group with acid etching (15.26 ± 4.16 MPa). Irradiation with 100 mj resulted in mean bond strengths of 9.05 ± 3.16 MPa, which was significantly different from that of acid etching (P < 0.001). Conclusions: laser etching at 150 and 100 mj was adequate for bond strength but the failure pattern of brackets bonded with laser etching is dominantly at adhesive – enamel interface and is not safe for enamel during debonding. PMID:23087733

  15. Electrostatic painting of nonconductive surfaces with water-base paints

    SciTech Connect

    Inculet, I.I. [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering] [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering; Klein, R.G. [Nordson Corp., Westlake, OH (United States)] [Nordson Corp., Westlake, OH (United States)

    1996-01-01

    Electrostatic corona painting on nonconductive surfaces normally requires a ground-connected conductive precoating of the surface in order to dissipate the continuously incoming ionic charge from the corona gun. If the surface charge does not flow to ground, the resulting surface electric field will repel a substantial amount of the incoming paint. The authors present a new painting method consisting of generating ultrasonically atomized electrically charged water particles behind the nonconductive surface to be painted. The paint spraying is carried out with a mechanical spray gun maintained at ground potential. The water base paint becomes charged by induction under the influence of the space charge behind the nonconductive surface to be painted. As the resulting charge on the water base paint particles is of opposite polarity to that of the ultrasonically atomized electrically charged water particles cloud, all propelling electric fields converge toward the surface to be painted. The results show excellent transfer efficiencies.

  16. Development of an AQUA Based Near-Surface Parameter Retrieval

    NASA Technical Reports Server (NTRS)

    Roberts, Brent; Clayson, Carol Anne

    2010-01-01

    The production of a satellite based turbulent surface flux product relies critically upon the near-surface input parameters. Development of retrieval algorithms for the necessary near-surface variables of wind speed, specific humidity, air temperature, and sea surface temperature has proceeded relatively independent of each another until recently. The use of a neural network approach using Special Sensor Microwave/Imager (SSM/I) data in conjunction with a first guess sea surface temperature has led to successful retrieval of all parameters simultaneously. However, SSM/I frequencies lack inherent sensitivity to the sea surface temperature (SST). Recent studies have found improved air temperature and humidity retrievals can be obtained via inclusion of microwave sounding channels weighted in the lower troposphere. The inclusion of SSM/I-like frequencies as well as SST-sensitive microwave channels on AMSR-E along with AMSU-A sounding data onboard the AQUA platform provides an unique opportunity. That is the ability to provide near-simultaneous (in space and time) measurements allowing the retrieval of all the near-surface variables, including SST. This study shows results of a new algorithm designed to take advantage of the unique sampling ability of AQUA based sensors. Results from a neural network based methodology will be shown as compared to in-situ based observations of near-surface variables. Implications for creation of an AQUA based turbulent surface product are also discussed.

  17. Relative kinetic frictional forces between sintered stainless steel brackets and orthodontic wires

    Microsoft Academic Search

    Janet L. Vaughan; Manville G. Duncanson; Ram S. Nanda; G. Fräns Currier

    1995-01-01

    The level of kinetic frictional forces generated during in vitro translation at the bracket-wire interface were measured for two sintered stainless steel brackets as a function of two slot sizes, four wire alloys, and five to eight wire sizes. The two types of sintered stainless steel brackets were tested in both 0.018-inch and 0.022-inch slots. Wires of four different alloy

  18. Bracketing subtle conformational energy differences between self-solvated and stretched trifluoropropanol.

    PubMed

    Heger, Matthias; Otto, Katharina E; Mata, Ricardo A; Suhm, Martin A

    2015-04-21

    The intramolecular OH···F hydrogen bond in 3,3,3-trifluoropropanol (TFP) exerts a subtle stabilizing effect that, when compared to the non-fluorinated analog, reorders the five distinguishable conformers and widens the gap between the two most stable structures. Here, we combine findings from Raman spectroscopy in supersonic expansions and high-level quantum-chemical calculations to bracket the energy difference between the two most stable TFP structures at 1.7(5) kJ mol(-1). The torsional potential energy surface suggests consecutive backbone and OH torsional motions for the conformer interconversion, which are discussed in the framework of supersonic jet cooling as a function of nozzle temperature. The picture of a bistable cold molecule with trans or gauche backbone emerges, in which the OH group controls the energy difference and modulates the high barrier separating the heavy atom frames. PMID:25776939

  19. Surface characterization of biopolyurethanes based on cellulose derivatives

    Microsoft Academic Search

    Doina Macocinschi; Daniela Filip; Maria Butnaru; Cristina Daniela Dimitriu

    2009-01-01

    Surface tension parameters and surface morphology of biopolyurethanes based on cellulose derivatives thin films, before and\\u000a after HF cold plasma treatment has been investigated. Calculations are based on the geometric mean approach of Owens and Wendt,\\u000a Rabel and Kälble, on the Lifshitz-van der Waals acid\\/base approach of van Oss and co-workers and on the theoretical methods\\u000a involving quantitative structure-property relationship.

  20. Nanoparticle-based etching of silicon surfaces

    DOEpatents

    Branz, Howard (Boulder, CO); Duda, Anna (Denver, CO); Ginley, David S. (Evergreen, CO); Yost, Vernon (Littleton, CO); Meier, Daniel (Atlanta, GA); Ward, James S. (Golden, CO)

    2011-12-13

    A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

  1. Ferroelectric based catalysis: Switchable surface chemistry

    NASA Astrophysics Data System (ADS)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2015-03-01

    We describe a new class of catalysts that uses an epitaxial monolayer of a transition metal oxide on a ferroelectric substrate. The ferroelectric polarization switches the surface chemistry between strongly adsorptive and strongly desorptive regimes, circumventing difficulties encountered on non-switchable catalytic surfaces where the Sabatier principle dictates a moderate surface-molecule interaction strength. This method is general and can, in principle, be applied to many reactions, and for each case the choice of the transition oxide monolayer can be optimized. Here, as a specific example, we show how simultaneous NOx direct decomposition (into N2 and O2) and CO oxidation can be achieved efficiently on CrO2 terminated PbTiO3, while circumventing oxygen (and sulfur) poisoning issues. One should note that NOx direct decomposition has been an open challenge in automotive emission control industry. Our method can expand the range of catalytically active elements to those which are not conventionally considered for catalysis and which are more economical, e.g., Cr (for NOx direct decomposition and CO oxidation) instead of canonical precious metal catalysts. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  2. Elemental composition of brazing alloys in metallic orthodontic brackets.

    PubMed

    Zinelis, Spiros; Annousaki, Olga; Eliades, Theodore; Makou, Margarita

    2004-06-01

    The aim of this study was to assess the elemental composition of the brazing alloy of representative orthodontic brackets. The brackets examined were Gemini (3M, Unitec, Monrovia, Calif), MicroLoc (GAC, Bohemia, NY), OptiMESHxrt (Ormco, Glendora, Calif), and Ultratrim (Dentarum, Ispringen, Germany). Four metallic brackets for each brand were embedded in epoxy resin and after metallographic grinding and polishing were cleaned in a water ultrasonic bath. Scanning electron microscopy and energy-dispersive x-ray microanalysis (EDS) were used to assess the quantitative composition of the brazing alloy. Four EDS spectra were collected for each brazing alloy, and the mean value and standard deviation for the concentration of each element were calculated. The elemental composition of the brazing alloys was determined as follows (percent weight): Gemini: Ni = 83.98 +/- 1.02, Si = 6.46 +/- 0.37, Fe = 5.90 +/- 0.93, Cr = 3.52 +/- 0.34; MicroLoc: Ag = 42.82 +/- 0.18, Au = 32.14 +/- 0.65, Cu = 24.53 +/- 0.26, Mg = 1.12 +/- 0.33; OptiMESHxrt: Au = 67.79 +/- 0.97, Fe = 15.69 +/- 0.29, Ni = 13.01 +/- 0.93, Cr = 4.01 +/- 0.35; Ultratrim: Ag = 87.97 +/- 0.33, Cu = 10.51 +/- 0.45, Mg = 1.29 +/- 0.63, Zn = 1.13 +/- 0.24. The findings of this study showed that different brazing materials were used for the different brands, and thus different performances are expected during intraoral exposure; potential effects on the biological properties also are discussed. PMID:15264653

  3. Patterned superhydrophobic surface based on Pd-based metallic glass

    NASA Astrophysics Data System (ADS)

    Xia, Ting; Li, Ning; Wu, Yue; Liu, Lin

    2012-08-01

    Without any modification or post-treatment, superhydrophobic surfaces with good stability were fabricated by hot-embossing honeycomb patterns on Pd40Cu30Ni10P20 bulk metallic glass (BMG). The water contact angle reaches above 150° when the pitch between adjacent cells is larger than the critical size of 115.5 ?m. The wetting behavior on the patterned BMG can be well rationalized in terms of the modified Cassie-Baxter theory [A. B. D. Cassie and S. Baxter, Trans. Faraday Soc. 40, 546 (1944)] by considering surface energy gradient. The achievement of the superhydrophobicity on BMG surface opens a window for the functional applications of metallic glasses.

  4. Femtosecond laser surface texturing of a nickel-based superalloy

    Microsoft Academic Search

    N. G. Semaltianos; W. Perrie; M. Sharp; G. Dearden; K. G. Watkins

    2008-01-01

    Femtosecond laser (180fs, 775nm, 1kHz) surface modification of the nickel-based superalloy C263 is investigated. The laser beam was scanned onto areas on the substrate with macroscopic dimensions using different fluences (F=0.28–30J\\/cm2), speeds (?=1–10mm\\/s) and number of overscans (5–90). The evolution of surface morphology, roughness, ablation depth and volume ablation rate with laser micromachining parameters were determined. The surface morphology is

  5. Photoinduced surface relief studies in an acrylamide-based photopolymer

    Microsoft Academic Search

    Pavani Kotakonda; Izabela Naydenova; Suzanne Martin; Vincent Toal

    2007-01-01

    Surface relief gratings (SRGs) have been optically recorded in a dry, self-developing acrylamide-based photopolymer. An investigation of the dependence of photoinduced surface relief amplitude and profile on recording intensity, UV post-exposure, thickness of the sample, composition of the photopolymer and temperature at constant spatial frequency was carried out using white light interferometry. Non-sinusoidal surface relief grating profiles which depend on

  6. Surface Reconstruction from Feature Based Stereo Camillo J. Taylor

    E-print Network

    Taylor, Camillo J.

    about the struc- ture of the scene based on quasi-sparse correspondences in multiple image. Effective of complex scenes from the quasi-sparse data re- turned by a feature based stereo system. The method can the scene. Based on this information, the system constructs a mesh representation of the surface like

  7. Small reactor power systems for manned planetary surface bases

    Microsoft Academic Search

    Harvey S. Bloomfield

    1987-01-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a

  8. Shape-Based Cortical Surface Segmentation for Visualization Brain Mapping

    Microsoft Academic Search

    Kevin P. Hinshaw; Andrew V. Poliakov; Eider B. Moore; Richard F. Martin; Linda G. Shapiro; James F. Brinkley

    2002-01-01

    We describe a knowledge-based approach to cortical surface segmentation that uses learned knowledge of the overall shape and range of variation of the cortex (excluding the detailed gyri and sulci) to guide the search for the grey-CSF boundary in a structural MRI image volume. The shape knowledge is represented by a radial surface model, which is a type of geometric

  9. Approximation for Deforming Surface Sequence Based on Triangle Optimization

    Microsoft Academic Search

    Shixue Zhang; Enhua Wu

    2008-01-01

    Many graphics applications represent deformable surfaces through dynamic meshes. Such models often contain redundant details, which can be difficult for processing and transmission. In this paper, we propose an efficient method to generate multiresolution models for deforming surface sequence based on triangle optimization. We use an improved quadric error metric (QEM) criterion as our basic measurement, which can preserve more

  10. High sensitivity surface plasmon resonace sensor based on phase detection

    Microsoft Academic Search

    S. G Nelson; K. S Johnston; S. S Yee

    1996-01-01

    A surface plasmon resonance sensing technique based on optical heterodyne phase detection is presented. The theoretical sensitivity of this new method is compared with traditioal surface plasmon resonance technique. The results of phase detection modeling shows a strong dependence on sensor film thickness. With a practical configuration, the resolution of refractive index is predicted to be 5 × 10?7 refractive

  11. Remote surface water monitoring radio based telemetry system

    Microsoft Academic Search

    W. L. Goodwin; D. Baxter

    1993-01-01

    The Environmental Protection Department of EG&G Rocky Flats has designed and developed a unique Remote Surface Water Monitoring System using radio telemetry hardware and computer control software. The system is based on new technologies in microelectronics and environmental monitoring sensors. An engineering team, headed up by the Surface Water Division at EG&G, has proven that with careful evaluation of new

  12. Fractal surface synthesis based on two dimensional discrete Fourier transform

    NASA Astrophysics Data System (ADS)

    Zhou, Chao; Gao, Chenghui; Huang, Jianmeng

    2013-11-01

    The discrete Fourier transform(DFT) is used for fractional Brownian motion(FBM) surface synthesis in tribology(i.e., contact, sliding, and sealing, etc). However, the relationship between fractal parameters(fractal dimension and scale factor) and traditional parameters, the influence of fractal parameters on surface appearance, have not been deeply discussed yet. These lead to some kind of difficulty to ensure the synthesized surfaces with ideal fractal characteristic, required traditional parameters and geometric appearance. A quantitative relationship between fractal parameters and the root mean square deviation of surface ( Sq) is derived based on the energy conservation property between the space and frequency domain of DFT. Under the stability assumption, the power spectrum of a FBM surface is composed of concentric circles strictly, a series of FBM surfaces with prescribed Sq could be synthesized with given fractal dimension, scale factor, and sampling numbers, but the ten-point height( Sz), the skewness( Ssk) and the kurtosis( Sku) are still in random, where the probability distributions of Sz and Ssk are approximately normal distribution. Furthermore, by iterative searching, a surface with desired Abbott-Firestone curve could be obtained among those surfaces. An intuitive explanation for the influence of fractal dimension and scale factor on surface appearance is obtained by discussing the effects on the ratio of energy between high and low frequency components. Based on the relationship between Sq and surface energy, a filtering method of surface with controllable Sq is proposed. The proposed research ensures the synthesized surfaces possess ideal FBM properties with prescribed Sq, offers a method for selecting desired Abbott-Firestone curve of synthesized fractal surfaces, and makes it possible to control the Sq of surfaces after filtering.

  13. Spectrophotometric evaluation of dental bleaching under orthodontic bracket in enamel and dentin

    PubMed Central

    Correr, Americo-Bortolazzo; Rastelli, Alessandra-Nara-Souza; Lima, Débora-Alves-Nunes-Leite; Consani, Rafael-Leonardo-Xediek

    2014-01-01

    Aware of the diffusion capacity of bleaching in the dental tissues, many orthodontists are subjecting their patients to dental bleaching during orthodontic treatment for esthetic purposes or to anticipate the exchange of esthetic restorations after the orthodontic treatment. For this purpose specific products have been developed in pre-loaded whitening trays designed to fit over and around brackets and wires, with clinical efficacy proven. Objective: The objective of this study was to evaluate, through spectrophotometric reflectance, the effectiveness of dental bleaching under orthodontic bracket. Material and Methods: Thirty-two bovine incisors crown blocks of 8 mm x 8 mm height lengths were used. Staining of tooth blocks with black tea was performed for six days. They were distributed randomly into 4 groups (1-home bleaching with bracket, 2- home bleaching without bracket, 3- office bleaching with bracket, 4 office bleaching without bracket). The color evaluation was performed (CIE L * a * b *) using color reflectance spectrophotometer. Metal brackets were bonded in groups 1 and 3. The groups 1 and 2 samples were subjected to the carbamide peroxide at 15%, 4 hours daily for 21 days. Groups 3 and 4 were subjected to 3 in-office bleaching treatment sessions, hydrogen peroxide 38%. After removal of the brackets, the second color evaluation was performed in tooth block, difference between the area under the bracket and around it, and after 7 days to verified color stability. Data analysis was performed using the paired t-test and two-way variance analysis and Tukey’s. Results: The home bleaching technique proved to be more effective compared to the office bleaching. There was a significant difference between the margin and center color values of the specimens that were subjected to bracket bonding. Conclusions: The bracket bond presence affected the effectiveness of both the home and office bleaching treatments. Key words:Tooth bleaching, spectrophotometry, orthodontics. PMID:25593650

  14. SURFACE PROPERTIES OF SOY-BASED POLYSOAPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oils are obtained from abundantly available and renewable agricultural products. They are also biodegradable and safe to use. These properties make vegetable oils the preferred raw materials over petroleum-based oils for the manufacture of various consumer and industrial products. Veget...

  15. Surface-emitting laser-based optical switching: An update

    Microsoft Academic Search

    P. Zhou; J. Cheng; S. Z. Sun; S. Hersee; M. Osinski; J. Zolper; D. R. Meyers; G. A. Vawter

    1993-01-01

    The properties of vertical-cavity surface-emitting lasers (VCSELS) and VCSEL-based optical switches using MOCVD-grown epitaxial material are discussed and summarized. Additionally, some of the factors that limit their performance are discussed.

  16. TRIANGLE MESH-BASED EDGE DETECTION AND ITS APPLICATION TO SURFACE SEGMENTATION AND ADAPTIVE SURFACE SMOOTHING

    E-print Network

    Koschan, Andreas

    TRIANGLE MESH-BASED EDGE DETECTION AND ITS APPLICATION TO SURFACE SEGMENTATION AND ADAPTIVE SURFACE, Knoxville, TN 37996, USA yiyong@iristown.engr.utk.edu ABSTRACT Triangle meshes are widely used represented by triangle meshes. This paper proposes a robust edge detection algorithm for triangle meshes

  17. 1 INTRODUCTION Road surface maintenance is mainly based on measurements of road surface characteristics

    E-print Network

    Paris-Sud XI, Université de

    1 INTRODUCTION Road surface maintenance is mainly based on measurements of road surface as often as needed. Thus, French road managers dispose of measurements conducted only every three years for the national road network to define their road maintenance policy. To complete these periodically collected

  18. Revised calculation of four-particle harmonic-oscillator transformation brackets matrix

    NASA Astrophysics Data System (ADS)

    Mickevi?ius, S.; Germanas, D.; Kalinauskas, R. K.

    2013-02-01

    In this article we present a new, considerably enhanced and more rapid method for calculation of the matrix of four-particle harmonic-oscillator transformation brackets (4HOB). The new method is an improved version of 4HOB matrix calculations which facilitates the matrix calculation by finding the eigenvectors of the 4HOB matrix explicitly. Using this idea the new Fortran code for fast and 4HOB matrix calculation is presented. The calculation time decreases more than a few hundred times for large matrices. As many problems of nuclear and hadron physics structure are modeled on the harmonic oscillator (HO) basis our presented method can be useful for large-scale nuclear structure and many-particle identical fermion systems calculations. Program summaryTitle of program: HOTB_M Catalogue identifier: AEFQ_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFQ_v3_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 2149 No. of bytes in distributed program, including test data, etc.: 17576 Distribution format: tar.gz Programming language: Fortran 90. Computer: Any computer with Fortran 90 compiler. Operating system: Windows, Linux, FreeBSD, True64 Unix. RAM: Up to a few Gigabytes (see Tables 1 and 2 included in the distribution package) Classification: 17.16, 17.17. Catalogue identifier of previous version: AEFQ_v2_0 Journal reference of previous version: Comput. Phys. Comm. 182(2011)1377 Does the new version supersede the previous version?: Yes Nature of problem: Calculation of the matrix of the 4HOB in a more effective way, which allows us to calculate the matrix of the brackets up to a few hundred times more rapidly than in a previous version. Solution method: The method is based on compact expressions of 4HOB, presented in [1] and its simplifications presented in this paper. Reasons for new version: We facilitated the calculation of the 4HOB, based on the method presented in the section 'Theoretical aspects'. The new program version gives shorter calculation times for the 4HOB Summary of revisions: New subroutines for calculation of the matrix of the 4HOB. For theoretical issues of revision see the section 'Theoretical aspects'. Restrictions: The 4HOB matrices up to e=28. Running time: Depends on the dimension of the 4HOB matrix (see Tables 1 and 2 included in the distribution file). References: [1] D. Germanas, S. Mickevicius, R.K. Kalinauskas, Calculation of four-particle harmonic-oscillator transformation brackets, Computer Physics Communications 181, 420-425 (2010).

  19. A surface-acoustic-wave-based cantilever bio-sensor.

    PubMed

    De Simoni, Giorgio; Signore, Giovanni; Agostini, Matteo; Beltram, Fabio; Piazza, Vincenzo

    2015-06-15

    A scalable surface-acoustic-wave- (SAW-) based cantilevered device for portable bio-chemical sensing applications is presented. Even in the current, proof-of-principle implementation this architecture is shown to outperform commercial quartz-crystal microbalances in terms of sensitivity. Adhesion of analytes on a functionalized surface of the cantilever shifts the resonant frequency of a SAW-generating transducer due to the stress-induced variation of the speed of surface acoustic modes. We discuss the relevance of this approach for diagnostics applications based on miniaturized devices. PMID:25643594

  20. Novel spirometry based on optical surface imaging

    PubMed Central

    Li, Guang; Huang, Hailiang; Li, Diana G.; Chen, Qing; Gaebler, Carl P.; Sullivan, James; Zatcky, Joan; Rimner, Andreas; Mechalakos, James

    2015-01-01

    Purpose: To evaluate the feasibility of using optical surface imaging (OSI) to measure the dynamic tidal volume (TV) of the human torso during free breathing. Methods: We performed experiments to measure volume or volume change in geometric and deformable phantoms as well as human subjects using OSI. To assess the accuracy of OSI in volume determination, we performed experiments using five geometric phantoms and two deformable body phantoms and compared the values with those derived from geometric calculations and computed tomography (CT) measurements, respectively. To apply this technique to human subjects, an institutional review board protocol was established and three healthy volunteers were studied. In the human experiment, a high-speed image capture mode of OSI was applied to acquire torso images at 4–5 frames per second, which was synchronized with conventional spirometric measurements at 5 Hz. An in-house matlab program was developed to interactively define the volume of interest (VOI), separate the thorax and abdomen, and automatically calculate the thoracic and abdominal volumes within the VOIs. The torso volume change (TV C = ?Vtorso = ?Vthorax + ?Vabdomen) was automatically calculated using full-exhalation phase as the reference. The volumetric breathing pattern (BPv = ?Vthorax/?Vtorso) quantifying thoracic and abdominal volume variations was also calculated. Under quiet breathing, TVC should equal the tidal volume measured concurrently by a spirometer with a conversion factor (1.08) accounting for internal and external differences of temperature and moisture. Another matlab program was implemented to control the conventional spirometer that was used as the standard. Results: The volumes measured from the OSI imaging of geometric phantoms agreed with the calculated volumes with a discrepancy of 0.0% ± 1.6% (range ?1.9% to 2.5%). In measurements from the deformable torso/thorax phantoms, the volume differences measured using OSI imaging and CT imaging were 1.2% ± 2.1% (range ?0.5% to 3.6%), with a linear regression fitting (slope = 1.02 and R2 = 0.999). In volunteers, the relative error in OSI tidal volume measurement was ?2.2% ± 4.9% (range ?9.2% to 4.8%) and a correlation of r = 0.98 was found with spirometric measurement. The breathing pattern values of the three volunteers were substantially different from each other (BPv = 0.15, 0.45, and 0.32). Conclusions: This study demonstrates the feasibility of using OSI to measure breathing tidal volumes and breathing patterns with adequate accuracy. This is the first time that dynamic breathing tidal volume as well as breathing patterns is measured using optical surface imaging. The OSI-observed movement of the entire torso could serve as a new respiratory surrogate in the treatment room during radiation therapy. PMID:25832058

  1. In vitro physical, chemical, and biological evaluation of commercially available metal orthodontic brackets

    PubMed Central

    Kim, Joo Hyoung; Cha, Jung Yul

    2012-01-01

    Objective This in vitro study was undertaken to evaluate the physical, chemical, and biological properties of commercially available metal orthodontic brackets in South Korea, because national standards for these products are lacking. Methods Four bracket brands were tested for dimensional accuracy, (manufacturing errors in angulation and torque), cytotoxicity, composition, elution, and corrosion: Archist (Daeseung Medical), Victory (3M Unitek), Kosaka (Tomy), and Confidence (Shinye Odontology Materials). Results The tested rackets showed no significant differences in manufacturing errors in angulation, but Confidence brackets showed a significant difference in manufacturing errors in torque. None of the brackets were cytotoxic to mouse fibroblasts. The metal ion components did not show a regular increasing or decreasing trend of elution over time, but the volume of the total eluted metal ions increased: Archist brackets had the maximal Cr elution and Confidence brackets appeared to have the largest volume of total eluted metal ions because of excessive Ni elution. Confidence brackets showed the lowest corrosion resistance during potentiodynamic polarization. Conclusions The results of this study could potentially be applied in establishing national standards for metal orthodontic brackets and in evaluating commercially available products. PMID:23323244

  2. Poisson brackets for the dynamically interacting system of a 2-D cylinder and N point vortices

    Microsoft Academic Search

    Banavara Shashikanth

    2002-01-01

    The equations of motion of the dynamically interacting system of a 2-D rigid cylinder and N point vortices external to it will be presented. The Poisson bracket structure of this system, in the case when the vortex strengths sum to zero, will be shown to be the sum of the rigid body Lie-Poisson bracket on the dual of the Lie

  3. Analogues of the Objects of Lie Group Theory for Nonlinear Poisson Brackets

    Microsoft Academic Search

    M. V. Karasev

    1987-01-01

    For general degenerate Poisson brackets, analogues are constructed of invariant vector fields, invariant forms, Haar measure and adjoint representation. A pseudogroup operation is defined that corresponds to nonlinear Poisson brackets, and analogues are obtained for the three classical theorems of Lie. The problem of constructing global pseudogroups is examined. Bibliography: 49 titles. Bibtex entry for this abstract Preferred format for

  4. In vitro effects of two topical varnish materials and Er:YAG laser irradiation on enamel demineralization around orthodontic brackets.

    PubMed

    Ulkur, Feyza; Sungurtekin Ekçi, Elif; Nalbantgil, Didem; Sandalli, Nuket

    2014-01-01

    The aim of this in vitro was to evaluate the effects of tricalcium phosphate (TCP) and amorphous calcium phosphate (ACP) containing varnish materials and Er:YAG laser irradiation on enamel demineralization around orthodontic brackets. Forty extracted human premolar teeth were randomly divided into four treatment groups (i.e., 10 in each group): (1) 5% NaF-ACP varnish, (2) 5% NaF-TCP varnish, (3) Er:YAG laser, and (4) control (no treatment). Er:YAG laser was operated at a wavelength of 2.94 ?m and the energy output was 80 mJ per pulse; a pulse duration of 200 ?sec and and a frequency of 2 Hz were used with water cooling. All samples were then put into pH cycles. Surface microhardness values and representative SEM images were assessed. Surface microhardness values were evaluated using Kruskal-Wallis and Mann-Whitney U tests. The results revealed that demineralization was significantly lower in the TCP and ACP varnish groups, whereas mean surface microhardness values of the TCP varnish were found higher than the ACP (P < 0.05). TCP and ACP varnish materials were found effective for reducing enamel demineralization around orthodontic brackets. Use of Er:YAG laser irradiation as described in this study for inhibition of demineralization was found not satisfactory. PMID:24987734

  5. Evaluation of Self-Etching Adhesive and Er:YAG Laser Conditioning on the Shear Bond Strength of Orthodontic Brackets

    PubMed Central

    Contreras-Bulnes, Rosalía; Scougall-Vilchis, Rogelio J.; Rodríguez-Vilchis, Laura E.; Centeno-Pedraza, Claudia; Olea-Mejía, Oscar F.; Alcántara-Galena, María del Carmen Z.

    2013-01-01

    The purpose of this study was to evaluate the shear bond strength, the adhesive remnant index scores, and etch surface of teeth prepared for orthodontic bracket bonding with self-etching primer and Er:YAG laser conditioning. One hundred and twenty bovine incisors were randomly divided into four groups. In Group I (Control), the teeth were conditioned with 35% phosphoric acid for 15 seconds. In Group II the teeth were conditioned with Transbond Plus SEP (5?sec); III and IV were irradiated with the Er:YAG 150?mJ (11.0?J/cm2), 150?mJ (19.1?J/cm2), respectively, at 7–12?Hz with water spray. After surface preparation, upper central incisor stainless steel brackets were bonded with Transbond Plus Color Change Adhesive. The teeth were stored in water at 37°C for 24 hours and shear bond strengths were measured, and adhesive remnant index (ARI) was determined. The conditioned surface was observed under a scanning electron microscope. One-way ANOVA and chi-square test were used. Group I showed the significantly highest values of bond strength with a mean value of 8.2 megapascals (MPa). The lesser amount of adhesive remnant was found in Group III. The results of this study suggest that Er:YAG laser irradiation could not be an option for enamel conditioning. PMID:24228014

  6. In Vitro Effects of Two Topical Varnish Materials and Er:YAG Laser Irradiation on Enamel Demineralization around Orthodontic Brackets

    PubMed Central

    Sungurtekin Ekçi, Elif; Sandalli, Nuket

    2014-01-01

    The aim of this in vitro was to evaluate the effects of tricalcium phosphate (TCP) and amorphous calcium phosphate (ACP) containing varnish materials and Er:YAG laser irradiation on enamel demineralization around orthodontic brackets. Forty extracted human premolar teeth were randomly divided into four treatment groups (i.e., 10 in each group): (1) 5% NaF-ACP varnish, (2) 5% NaF-TCP varnish, (3) Er:YAG laser, and (4) control (no treatment). Er:YAG laser was operated at a wavelength of 2.94??m and the energy output was 80?mJ per pulse; a pulse duration of 200??sec and and a frequency of 2?Hz were used with water cooling. All samples were then put into pH cycles. Surface microhardness values and representative SEM images were assessed. Surface microhardness values were evaluated using Kruskal-Wallis and Mann-Whitney U tests. The results revealed that demineralization was significantly lower in the TCP and ACP varnish groups, whereas mean surface microhardness values of the TCP varnish were found higher than the ACP (P < 0.05). TCP and ACP varnish materials were found effective for reducing enamel demineralization around orthodontic brackets. Use of Er:YAG laser irradiation as described in this study for inhibition of demineralization was found not satisfactory. PMID:24987734

  7. Design of Surfaces for Liquid Crystal-Based Bioanalytical Assays

    PubMed Central

    Lowe, Aaron M.; Ozer, Byram H.; Bai, Yiqun; Bertics, Paul J.; Abbott, Nicholas L.

    2010-01-01

    Surface-induced ordering of liquid crystals (LCs) offers the basis of a label-free analytical technique for the detection of surface-bound biomolecules. The orientation-dependent energy of interaction of a LC with a surface (anchoring energy of LC), in particular, is both sensitive to the presence of surface-bound molecules and easily quantified. Herein we report a study that analyzes a simple model of twisted nematic LC systems and thereby identifies surfaces with LC anchoring energies in the range of 0.5 ?J/m2 to 2.0 ?J/m2 to be optimal for use with LC-based analytical methods. Guided by these predictions, we demonstrate that analytic surfaces possessing anchoring energies within this range can be fabricated with a high level of precision (< 0.1 ?J/m2) through formation of monolayers of organothiols (with ?-functional groups corresponding to oligoethyleneglycols and amines) on gold films deposited by physical vapor deposition at oblique angles of incidence. Finally, by using the human epidermal growth factor receptor (EGFR) as a model protein analyte, we have characterized the influence of the anchoring energies of the surfaces on the response of the LC to the presence of surface-bound EGFR. These results, when combined with 32P-radiolabeling of the EGFR to independently quantify the surface concentration of EGFR, permit identification of surfaces that allow use of LCs to report surface densities of EGFR of 70–90 pg/mm2. Overall, the results reported in this paper guide the design of surfaces for use in LC-based analytical systems. PMID:20356273

  8. Design of surfaces for liquid crystal-based bioanalytical assays.

    PubMed

    Lowe, Aaron M; Ozer, Byram H; Bai, Yiqun; Bertics, Paul J; Abbott, Nicholas L

    2010-03-01

    Surface-induced ordering of liquid crystals (LCs) offers the basis of a label-free analytical technique for the detection of surface-bound biomolecules. The orientation-dependent energy of interaction of a LC with a surface (anchoring energy of LC), in particular, is both sensitive to the presence of surface-bound molecules and easily quantified. Herein, we report a study that analyzes a simple model of twisted nematic LC systems and thereby identifies surfaces with LC anchoring energies in the range of 0.5 microJ/m(2) to 2.0 microJ/m(2) to be optimal for use with LC-based analytical methods. Guided by these predictions, we demonstrate that analytic surfaces possessing anchoring energies within this range can be fabricated with a high level of precision (< 0.1 microJ/m(2)) through formation of monolayers of organothiols (with omega-functional groups corresponding to oligoethyleneglycols and amines) on gold films deposited by physical vapor deposition at oblique angles of incidence. Finally, by using the human epidermal growth factor receptor (EGFR) as a model protein analyte, we have characterized the influence of the anchoring energies of the surfaces on the response of the LC to the presence of surface-bound EGFR. These results, when combined with (32)P-radiolabeling of the EGFR to independently quantify the surface concentration of EGFR, permit identification of surfaces that allow use of LCs to report surface densities of EGFR of 30-40 pg/mm(2). Overall, the results reported in this paper guide the design of surfaces for use in LC-based analytical systems. PMID:20356273

  9. Surface bond strength in nickel based alloys.

    PubMed

    Ramesh, Ganesh; Padmanabhan, T V; Ariga, Padma; Joshi, Shalini; Bhuminathan, S; Vijayaraghavan, Vasantha

    2013-12-01

    Bonding of ceramic to the alloy is essential for the longevity of porcelain fused to metal restorations. Imported alloys used now a days in processing them are not economical. So this study was conducted to evaluate and compare the bond strength of ceramic material to nickel based cost effective Nonferrous Materials Technology Development Center (NFTDC), Hyderabad and Heraenium S, Heraeus Kulzer alloy. An Instron testing machine, which has three-point loading system for the application of load onto the specimen was utilized for analyzing bond strength of both alloys. Student t test was conducted and t value obtained was 0.644, and the mean value of flexural bond strength of indigenous alloy is 81.75 with standard deviation of 12.25 and of imported alloy is 84.42 with standard deviation of 10.35, indicating that there was no significant difference between the two alloys. Due to ever increasing cost of imported non-precious alloy the need for a cost-effective replacement was fulfilled by indigenous NFTDC alloy. PMID:24431791

  10. Relative kinetic frictional forces between sintered stainless steel brackets and orthodontic wires.

    PubMed

    Vaughan, J L; Duncanson, M G; Nanda, R S; Currier, G F

    1995-01-01

    The level of kinetic frictional forces generated during in vitro translation at the bracket-wire interface were measured for two sintered stainless steel brackets as a function of two slot sizes, four wire alloys, and five to eight wire sizes. The two types of sintered stainless steel brackets were tested in both 0.018-inch and 0.022-inch slots. Wires of four different alloy types, stainless steel (SS), cobalt chromium (Co-Cr), nickel-titanium (Ni-Ti), and beta-titanium (beta-Ti), were tested. There were five wire sizes for the 0.018-inch slot and eight wire sizes for the 0.022-inch slot. The wires were ligated into the brackets with elastomeric ligatures. Bracket movement along the wire was implemented by means of a mechanical testing instrument, and time dependent frictional forces were measured by a load cell and plotted on an X-Y recorder. For most wire sizes, lower frictional forces were generated with the SS of Co-Cr wires than with the beta-Ti or Ni-Ti wires. Increase in wire size generally resulted in increased bracket-wire friction. There were no significant differences between manufacturer for the sintered stainless steel brackets. The levels of frictional force in 0.018-inch brackets ranged from a low of 46 gm with 0.016-inch Co-Cr wire to a high of 157 gm with 0.016 x 0.025-inch beta-Ti wire. In comparing the data from a previous study by Kapila et al. 1990 performed at OUHSC with the same apparatus, the friction of sintered stainless steel brackets was approximately 40% to 45% less than the friction of the conventional stainless steel brackets. PMID:7817958

  11. Plasma versus Halogen Light: the Effect of Different Light Sources on the Shear Bond Strength of Brackets

    Microsoft Academic Search

    Stephanie Neugebauer; Paul-Georg Jost-Brinkmann; Boris Pätzold; Vittorio Cacciafesta

    2004-01-01

    The aim of this study was to investigate differences between plasma and halogen light polymerization in relation to the attainable shear bond strength of brackets bonded with various adhesives. 720 brackets were divided into 72 different groups of n = 10. The brackets were bonded to 240 flat polished test specimens produced from bovine teeth, Pontor ® MPF alloy, and

  12. Mechanically robust superhydrophobic polymer surfaces based on protective micropillars.

    PubMed

    Huovinen, Eero; Takkunen, Laura; Korpela, Tarmo; Suvanto, Mika; Pakkanen, Tuula T; Pakkanen, Tapani A

    2014-02-11

    Considerable attention is currently being devoted less to the question of whether it is possible to produce superhydrophobic polymer surfaces than to just how robust they can be made. The present study demonstrates a new route for improving the mechanical durability of water-repellent structured surfaces. The key idea is the protection of fragile fine-scale surface topographies against wear by larger scale sacrificial micropillars. A variety of surface patterns was manufactured on polypropylene using a microstructuring technique and injection molding. The surfaces subjected to mechanical pressure and abrasive wear were characterized by water contact and sliding angle measurements as well as by scanning electron microscopy and roughness analysis based on optical profilometry. The superhydrophobic polypropylene surfaces with protective structures were found to maintain their wetting properties in mechanical compression up to 20 MPa and in abrasive wear tests up to 120 kPa. For durable properties, the optimal surface density of the protective pillars was found to be about 15%. The present approach to the production of water-repellent polymer surfaces provides the advantages of mass production and mechanical robustness with practical applications of structurally functionalized surfaces. PMID:24483340

  13. Contour-Based Surface Reconstruction using MPU Implicit Models

    PubMed Central

    Braude, Ilya; Marker, Jeffrey; Museth, Ken; Nissanov, Jonathan; Breen, David

    2007-01-01

    This paper presents a technique for creating a smooth, closed surface from a set of 2D contours, which have been extracted from a 3D scan. The technique interprets the pixels that make up the contours as points in ?3 and employs Multi-level Partition of Unity (MPU) implicit models to create a surface that approximately fits to the 3D points. Since MPU implicit models additionally require surface normal information at each point, an algorithm that estimates normals from the contour data is also described. Contour data frequently contains noise from the scanning and delineation process. MPU implicit models provide a superior approach to the problem of contour-based surface reconstruction, especially in the presence of noise, because they are based on adaptive implicit functions that locally approximate the points within a controllable error bound. We demonstrate the effectiveness of our technique with a number of example datasets, providing images and error statistics generated from our results. PMID:18496609

  14. Correction of palatally displaced maxillary lateral incisors without brackets

    PubMed Central

    Choi, Kyung-Hee; Lee, Yoonjung; Kim, Minji

    2013-01-01

    This article describes the orthodontic treatment of a 25-year-old Korean female patient with anterior crowding, including palatally displaced lateral incisors. Her facial profile was satisfactory, but 3.5 mm of maxillary anterior crowding was observed. To correct this crowding, we decided to minimize the use of the conventional fixed orthodontic appliances and employed a less bulky and more aesthetic appliance for applying light continuous force. We determined the final positions of the maxillary teeth via a working model for diagnostic set up and achieved space gaining and alignment with simple Ni-Ti spring and stainless steel round tubes. Tooth alignment was achieved efficiently and aesthetically without the conventional brackets. PMID:24015390

  15. A pyramidal data structure for triangle-based surface description

    Microsoft Academic Search

    Leila De Floriani

    1989-01-01

    A hierarchical model for approximating 2-1\\/2-dimensional surfaces is described. This model, called a Delaunay pyramid, is a method for compression of spatial data and representation of a surface at successively finer levels of detail. A Delaunay pyramid is based on a sequence of Delaunay triangulations of suitably defined subsets of the set of data points. A triangle-oriented encoding structure for

  16. Inference-based surface reconstruction of cluttered environments.

    PubMed

    Biggers, Keith; Keyser, John

    2012-08-01

    We present an inference-based surface reconstruction algorithm that is capable of identifying objects of interest among a cluttered scene, and reconstructing solid model representations even in the presence of occluded surfaces. Our proposed approach incorporates a predictive modeling framework that uses a set of user-provided models for prior knowledge, and applies this knowledge to the iterative identification and construction process. Our approach uses a local to global construction process guided by rules for fitting high-quality surface patches obtained from these prior models. We demonstrate the application of this algorithm on several example data sets containing heavy clutter and occlusion. PMID:21968935

  17. Comparison of Surface Plasmon Resonance and Localized Surface Plasmon Resonance-based optical fibre sensors

    Microsoft Academic Search

    J. Cao; E. K. Galbraith; T. Sun; K. T. V. Grattan

    2011-01-01

    In this work, two of surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR)-based optical fibre sensors have been successfully developed and cross-compared. With one SPR sensor being coated with a thin layer of gold film and the other gold-nanorods (GNRs), forming a LSPR sensor, both sensors are subjected to various refractive index changes. As a result their sensitivities

  18. Nanoparticle-Based Surface Modifications for Microtribology Control and Superhydrophobicity

    NASA Astrophysics Data System (ADS)

    Hurst, Kendall Matthew

    2010-11-01

    The emergence of miniaturization techniques for consumer electronics has brought forth the relatively new and exciting field of microelectromechanical systems (MEMS). However, due to the inherent forces that exist between surfaces at the micro- and nanoscale, scientists and semiconductor manufacturers are still struggling to improve the lifetime and reliability of complex microdevices. Due to the extremely large surface area-to-volume ratio of typical MEMS and microstructured surfaces, dominant interfacial forces exist which can be detrimental to their operational lifetime. In particular, van der Waals, capillary, and electrostatic forces contribute to the permanent adhesion, or stiction , of microfabricated surfaces. This strong adhesion force also contributes to the friction and wear of these silicon-based systems. The scope of this work was to examine the effect of utilizing nanoparticles as the basis for roughening surfaces for the purpose of creating films with anti-adhesive and/or superhydrophobic properties. All of the studies presented in this work are focused around a gas-expanded liquid (GXL) process that promotes the deposition of colloidal gold nanoparticles (AuNPs) into conformal thin films. The GXL particle deposition process is finalized by a critical point drying step which is advantageous to the microelectromechanical systems and semiconductor (IC) industries. In fact, preliminary results illustrated that the GXL particle deposition process can easily be integrated into current MEMS microfabrication processes. Thin films of AuNPs deposited onto the surfaces of silicon-based MEMS and tribology test devices were shown to have a dramatic effect on the adhesion of microstructures. In the various investigations, the apparent work of adhesion between surfaces was reduced by 2-4 orders of magnitude. This effect is greatly attributed to the roughening of the typically smooth silicon oxide surfaces which, in turn, dramatically decreases the "real are of contact" between two contacting surfaces. The studies found that AuNP thin films produced using the lowest initial concentrations of nanoparticles in solution produced estimated real contact areas of around 1%, reducing the adhesion of oxidized Si (100) surfaces from about 37 mJ/m2 down to 0.02 mJ/m 2. In addition, the reducing in real contact area effectively reduced the coefficient of static friction between silicon-based surfaces due to the extremely high dependence of stiction on friction and wear at the microscale. This work also investigated methods of permanently immobilizing AuNP-based films on the silicon surfaces of microstructures in order to create more mechanically robust coatings. The use of organic self-assembled monolayers (SAMs) functionalized with tail-groups known to bond to metallic surfaces were effective in producing much more durable coatings as opposed to non-immobilized AuNP films. Chemical vapor deposition (CVD) techniques were also used to coat rough AuNP films with very thin films of silica (SiO2) to create a robust, rough surface. This method was also very effective in creating a durable coating which is capable of reducing the adhesion energy and friction between two microscale surfaces for extended periods of time. Similar CVD techniques were also used to begin investigating the production of alumina nanoparticle-based superhydrophobic films for use in consumer electronics. Overall, the work presented in this dissertation illustrates that engineered nanoparticle-based surface modifications can be extremely effective in the reduction of the inherent interfacial phenomena that exist on microfabricated systems. This work is can potentially lead us into a new age of the miniaturization of mechanical and electronic devices.

  19. In vitro study of color stability of polycrystalline and monocrystalline ceramic brackets

    PubMed Central

    de Oliveira, Cibele Braga; Maia, Luiz Guilherme Martins; Santos-Pinto, Ary; Gandini Júnior, Luiz Gonzaga

    2014-01-01

    Objective The aim of this in vitro study was to analyze color stability of monocrystalline and polycrystalline ceramic brackets after immersion in dye solutions. Methods Seven ceramic brackets of four commercial brands were tested: Two monocrystalline and two polycrystalline. The brackets were immersed in four dye solutions (coffee, red wine, Coke and black tea) and in artificial saliva for the following times: 24 hours, 7, 14 and 21 days, respectively. Color changes were measured by a spectrophotometer. Data were assessed by Multivariate Profile Analysis, Analysis of Variance (ANOVA) and Multiple Comparison Tests of means. Results There was a perceptible change of color in all ceramic brackets immersed in coffee (?E* Allure = 7.61, Inspire Ice = 6.09, Radiance = 6.69, Transcend = 7.44), black tea (?E* Allure = 6.24, Inspire Ice = 5.21, Radiance = 6.51, Transcend = 6.14) and red wine (?E* Allure = 6.49, Inspire Ice = 4.76, Radiance = 5.19, Transcend = 5.64), but no change was noticed in Coke and artificial saliva (?E < 3.7). Conclusion Ceramic brackets undergo color change when exposed to solutions of coffee, black tea and red wine. However, the same crystalline structure, either monocrystalline or polycrystalline, do not follow the same or a similar pattern in color change, varying according to the bracket fabrication, which shows a lack of standardization in the manufacturing process. Coffee dye produced the most marked color changes after 21 days of immersion for most ceramic brackets evaluated. PMID:25279530

  20. Mesogondolella and Jinogondolella (Conodonta): Multielement definition of the taxa that bracket the basal Guadalupian (Middle Permian Series) GSSP

    USGS Publications Warehouse

    Lambert, L.L.; Wardlaw, B.R.; Henderson, C.M.

    2007-01-01

    Multielement definitions are presented here for Mesogondolella and Jinogondolella based on species that bracket the basal Guadalupian (Middle Permian Series) GSSP. Distinctive apparatus characters that appear with the first Jinogondolella include several details of P2 element dimorphism and process bifurcation in S3 elements. The sequential expression of these multielement characters is traced through M. idahoensis, M. lamberti, and J. nankingensis. The resulting multielement definition of Jinogondolella serves to distinguish it from all other closely related genera. Mesogondolella lamberti is recognized as a distinct species, and J. serrata is formally designated a junior synonym of J. nankingensis. ?? 2007 Nanjing Institute of Geology and Palaeontology, CAS.

  1. In vitro assessment of competency for different lingual brackets in sliding mechanics

    PubMed Central

    Lalithapriya, S; Kumaran, N Kurunji; Rajasigamani, K

    2015-01-01

    Aim: To determine the static frictional resistance of different lingual brackets at different second order angulations when coupled with stainless steel (SS) archwire in dry and wet conditions. Materials and Methods: Using a modified jig, frictional resistance was evaluated under different conditions for a total of 270 upper premolar lingual brackets (0.018? × 0.025? - conventional - 7th generation and STb, self-ligating – evolution) with no in-built tip or torque together with 0.016? × 0.022? straight length SS archwires. For conventional brackets, the archwire was secured with 0.008? preformed SS short ligature ties. Statistical Analysis: One way analysis of variance with Tukey HSD as post-hoc test was applied for degree wise and bracket wise comparison within dry condition and wet condition. For pair wise comparison Student's t-test was used. Results: Under both conditions the static frictional resistance is significantly higher for self-ligating brackets at 0°, while at 5° and 10° it is higher for 7th generation brackets. Statistically, significant difference does not exist at 0° between conventional brackets and the same was found at 5° and 10° between STb and self-ligating brackets. With an increase in second order angulations, all the evaluated samples exhibited an increased frictional value. Wet condition samples obtained a higher value than their corresponding dry condition. Conclusion: The self-ligating bracket evaluated in this in vitro study is not beneficial in reducing friction during en-mass retraction due to its interactive clip type. PMID:25657988

  2. Reduction of Almost Poisson brackets and Hamiltonization of the Chaplygin Sphere

    E-print Network

    Garcia-Naranjo, Luis C

    2008-01-01

    We construct different almost Poisson brackets for nonholonomic systems than those existing in the literature and study their reduction. Such brackets are built by considering non-canonical two-forms on the cotangent bundle of configuration space and then carrying out a projection onto the constraint space that encodes the Lagrange-D'Alembert principle. We justify the need for this type of brackets by working out the reduction of the celebrated Chaplygin sphere rolling problem. Our construction provides a geometric explanation of the Hamiltonization of the problem given by A. V. Borisov and I. S. Mamaev.

  3. In vitro analysis of femtosecond laser as an alternative to acid etching for achieving suitable bond strength of brackets to human enamel.

    PubMed

    Lorenzo, M C; Portillo, M; Moreno, P; Montero, J; Castillo-Oyagüe, R; García, A; Albaladejo, A

    2014-05-01

    This study aims to evaluate the effect of laser irradiation and orthophosphoric acid etching on the shear bond strength (SBS) of orthodontic brackets to enamel. Three groups (n = 20) of extracted premolar teeth were randomly established depending on the laser treatment performed on the buccal surfaces: (1) no laser (control); (2) Er:YAG laser (2,940 nm, 0.8 W, 100 ?s/pulse, 10 Hz) and; (3) Ti:Sapphire laser (795 nm, 1 W, 120 fs/pulse, 1 kHz). Each group was divided into two subgroups according to whether 37%-orthophosphoric acid etching was made after laser irradiation or not. Brackets were randomly luted with Transbond(TM) XT adhesive resin. After 72 h, a SBS test was developed in a universal testing machine (crosshead speed, 0.5 mm/min). Representative specimens from each experimental subgroup were examined by means of scanning electron microscopy. Cement residuals remaining on the premolar surfaces were assessed using the adhesive remnant index. ANOVA, post-hoc tests for intergroup comparisons, chi-square test and linear regression were run for data analyses (? = 0.05). After acid etching, SBS values did not differ regardless the laser treatment. When phosphoric acid was not applied, the SBS values of the femtosecond laser group were significantly higher than for the other groups. Femtosecond laser without acid seems to be the most suitable method to improve bond strengths at the bracket/enamel interface, thus avoiding the disadvantages inherent to acid etching. PMID:23483297

  4. Chemical sensors based on surface-confined dendrimers

    SciTech Connect

    Tokuhisa, Hideo; Crooks, R.M. [Texas A& M Univ., College Station, TX (United States). Dept. of Chemistry; Ricco, A.J.; Osbourn, G.C. [Sandia National Labs., Albuquerque, NM (United States)

    1997-10-01

    The use of dendrimers for preparing chemically sensitive interfaces for detecting volatile organic compounds (VOCs) using surface acoustic wave (SAW) device transducers is described. Specifically, the synthesis of the dendrimers and the means by which they are affixed to SAW devices is discussed, followed by a detailed spectroscopic analysis of the surface-confined dendrimers and a discussion of their interaction with different VOCs. Most of these preliminary experiments focus on dendrimer surface modification using benzoylchloride, which leads to phenyl terminal groups linked to the dendrimer via amide groups. The results of this study lead us to conclude that dendrimers: (1) provide general specificity towards classes of functional groups and are therefore suitable for array-based sensing schemes; (2) are intermediate in structure between monolayers and polymers and exhibit the desirable properties of both; (3) can be straightforwardly attached to the surfaces of acoustic wave devices.

  5. Controllable adhesive superhydrophobic surfaces based on PDMS microwell arrays.

    PubMed

    Yong, Jiale; Chen, Feng; Yang, Qing; Zhang, Dongshi; Bian, Hao; Du, Guangqing; Si, Jinhai; Meng, Xiangwei; Hou, Xun

    2013-03-12

    This paper presents a one-step method to fabricate superhydrophobic surfaces with extremely controllable adhesion based on PDMS microwell arrays. The microwell array structures are rapidly produced on PDMS films by a point-by-point femtosecond laser scanning process. The as-prepared superhydrophobic surfaces show water controllable adhesion that ranges from ultrahigh to ultralow by adjusting the extent of overlap of the adjacent microwells, on which the sliding angle can be controlled from 180° (a water droplet can not slide down even when the as-prepared surface is turned upside down) to 3°. A "micro-airbag effect" is introduced to explain the adhesion transition phenomenon of the microwell array structures. This work provides a facile and promising strategy to fabricate superhydrophobic surfaces with controllable adhesion. PMID:23391207

  6. Land surface albedo based on GOES geostationary satellite observations

    NASA Astrophysics Data System (ADS)

    Matthews, J. L.; Lattanzio, A.; Hankins, B.; Knapp, K.; Privette, J. L.

    2012-12-01

    Land surface albedo is the fraction of incoming solar radiation reflected by the land surface, and therefore can be a sensitive indicator of environmental changes. To this end, surface albedo is identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). NOAA's National Climatic Data Center (NCDC) recently adapted the Geostationary Surface Albedo (GSA; Lattanzio and Govaerts, 2010) algorithm for use with GOES data in support of a global albedo initiative led by the Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM). SCOPE-CM helps coordinate ECV production responding to GCOS, WMO, and CEOS goals. The GSA algorithm was developed jointly by EUMETSAT and Joint Research Centre (JRC) using a method proposed by Pinty et al. (2000) to determine surface albedo using day-time, cloud-free geostationary observations from a single visible band. For the GOES implementation, raw GOES observations are calibrated using International Satellite Cloud Climatology Project (ISCCP) coefficients. Surface angular anisotropy is determined through the inversion of the GSA radiative transfer model using multiple geostationary images collected over a day under different illumination conditions. The inversion process requires ancillary total column ozone and water vapor values, which are acquired from the 20th Century Reanalysis V2 data set. The GSA algorithm produces a 10-day composite surface albedo map. This product is initially being developed for the years 2000-2003. Product quality is being assessed through comparisons with MODIS products as well as ground-based measurements. NCDC is producing albedo products from both GOES-E (75°W) and GOES-W (135°W). These are being merged with like products from EUMETSAT based on METEOSAT (0° and 63°E) and from JMA based on the Geostationary Meteorological Satellite System (140°E). In the near future, NOAA's Climate Data Record Program will provide the albedo product over the entire GOES period of record (1978-present).

  7. Response Mechanism for Surface Acoustic Wave Gas Sensors Based on Surface-Adsorption

    PubMed Central

    Liu, Jiansheng; Lu, Yanyan

    2014-01-01

    A theoretical model is established to describe the response mechanism of surface acoustic wave (SAW) gas sensors based on physical adsorption on the detector surface. Wohljent's method is utilized to describe the relationship of sensor output (frequency shift of SAW oscillator) and the mass loaded on the detector surface. The Brunauer-Emmett-Teller (BET) formula and its improved form are introduced to depict the adsorption behavior of gas on the detector surface. By combining the two methods, we obtain a theoretical model for the response mechanism of SAW gas sensors. By using a commercial SAW gas chromatography (GC) analyzer, an experiment is performed to measure the frequency shifts caused by different concentration of dimethyl methylphosphonate (DMMP). The parameters in the model are given by fitting the experimental results and the theoretical curve agrees well with the experimental data. PMID:24743157

  8. A combined voxel and surface based method for topology correction of brain surfaces

    NASA Astrophysics Data System (ADS)

    Gris, Florence; Favreau, Jean-Marie; Acosta, Oscar; Barra, Vincent; Salvado, Olivier

    2010-03-01

    Brain surfaces provide a reliable representation for cortical mapping. The construction of correct surfaces from magnetic resonance images (MRI) segmentation is a challenging task, especially when genus zero surfaces are required for further processing such as parameterization, partial inflation and registration. The generation of such surfaces has been approached either by correcting a binary image as part of the segmentation pipeline or by modifying the mesh representing the surface. During this task, the preservation of the structure may be compromised because of the convoluted nature of the brain and noisy/imperfect segmentations. In this paper, we propose a combined, voxel and surfacebased, topology correction method which preserves the structure of the brain while yielding genus zero surfaces. The topology of the binary segmentation is first corrected using a set of topology preserving operators applied sequentially. This results in a white matter/gray matter binary set with correct sulci delineation, homotopic to a filled sphere. Using the corrected segmentation, a marching cubes mesh is then generated and the tunnels and handles resulting from the meshing are finally removed with an algorithm based on the detection of nonseparating loops. The approach was validated using 20 young individuals MRI from the OASIS database, acquired at two different time-points. Reproducibility and robustness were evaluated using global and local criteria such as surface area, curvature and point to point distance. Results demonstrated the method capability to produce genus zero meshes while preserving geometry, two fundamental properties for reliable and accurate cortical mapping and further clinical studies.

  9. Wavelet Frame Based Surface Reconstruction from Unorganized Points

    E-print Network

    Zakharov, Vladimir

    Wavelet Frame Based Surface Reconstruction from Unorganized Points Bin Donga, , Zuowei Shenb, 119076. Abstract Applications of wavelet frames to image restoration problems (e.g. image deblurring smooth functions like images (see e.g. [13, 14, 8]). However, wavelet frames have not yet been used

  10. A Surface-Based Approach to Quantify Local Cortical Gyrification

    Microsoft Academic Search

    Marie Schaer; Meritxell Bach Cuadra; Lucas Tamarit; François Lazeyras; Stephan Eliez; Jean-philippe Thiran

    2008-01-01

    The high complexity of cortical convolutions in hu- mans is very challenging both for engineers to measure and com- pare it, and for biologists and physicians to understand it. In this paper, we propose a surface-based method for the quantification of cortical gyrification. Our method uses accurate 3-D cortical re- construction and computes local measurements of gyrification at thousands of

  11. Equations of parametric surfaces with base points via syzygies

    Microsoft Academic Search

    William A. Adkins; J. William Hoffman; Hao Hao Wang

    2005-01-01

    Let S be a parametrized surface in P3 given as the image of ? : P1 × P1 ! P3. This paper will show that the use of syzygies in the form of a combination of moving planes and moving quadrics provides a valid method for finding the implicit equation of S when certain base points are present. This work

  12. COLREGs-based collision avoidance strategies for unmanned surface vehicles

    Microsoft Academic Search

    Wasif Naeem; George W. Irwin; Aolei Yang

    The aim of this paper is to report the preliminary development of an automatic collision avoidance technique for unmanned marine craft based on standardised rules, COLREGs, defined by the International Maritime Organisation. It is noted that all marine surface vessels are required to adhere to COLREGs at all times in order to minimise or eliminate the risk of collisions. The

  13. PHYSICALLY-BASED B-SPLINE SURFACE Colette J. Mullenho

    E-print Network

    Utah, University of

    PHYSICALLY-BASED B-SPLINE SURFACE SCULPTING by Colette J. Mullenho A thesis submitted of Science Department of Computer Science The University of Utah December 1998 #12;Copyright c Colette J of a thesis submitted by Colette J. Mullenho This thesis has been read by each member of the following

  14. Satellite-based estimation of surface vapor pressure deficits using MODIS land surface temperature data

    Microsoft Academic Search

    Hirofumi Hashimoto; Jennifer L. Dungan; Michael A. White; Feihua Yang; Andrew R. Michaelis; Steven W. Running; Ramakrishna R. Nemani

    2008-01-01

    Vapor Pressure Deficit (VPD) is a principle mediator of global terrestrial CO2 uptake and water vapor loss through plant stomata. As such, methods to estimate VPD accurately and efficiently are critical for ecosystem and climate modeling efforts. Based on prior work relating energy partitioning, remotely sensed land surface temperature (LST), and VPD, we developed simple linear models to predict VPD

  15. Resistance to Sliding in Clear and Metallic Damon 3 and Conventional Edgewise Brackets: an In vitro Study

    PubMed Central

    Karim Soltani, Mohammad; Golfeshan, Farzaneh; Alizadeh, Yoones; Mehrzad, Jabraiel

    2015-01-01

    Statement of the Problem Frictional forces are considered as important counterforce to orthodontic tooth movement. It is claimed that self-ligating brackets reduce the frictional forces. Purpose The aim of this study was to compare the resistance to sliding in metallic and clear Damon brackets with the conventional brackets in a wet condition. Materials and Method The samples included 4 types of brackets; metallic and clear Damon brackets and metallic and clear conventional brackets (10 brackets in each group). In this study, stainless steel wires sized 0.019×0.025 were employed and the operator’s saliva was used to simulate the conditions of oral cavity. The tidy-modified design was used for simulation of sliding movement. The resistance to sliding and static frictional forces was measured by employing Testometric machine and load cell. Results The mean (±SD) of resistance to sliding was 194.88 (±26.65) and 226.62 (±39.9) g in the esthetic and metallic Damon brackets, while these values were 187.81(±27.84) and 191.17(±66.68) g for the clear and metallic conventional brackets, respectively. Static frictional forces were 206.4(±42.45) and 210.38(±15.89) g in the esthetic and metallic Damon brackets and 220.63(±49.29) and 215.13(±62.38) g in the clear and metallic conventional brackets. According to two-way ANOVA, no significant difference was observed between the two bracket materials (clear and metal) and the two types of bracket (self-ligating versus conventional) regarding resistance to sliding (p= 0.17 and p= 0.23, respectively) and static frictional forces (p= 0.55 and p= 0.96, respectively). Conclusion Neither the type of bracket materials nor their type of ligation made difference in resistance to sliding and static friction.

  16. Laser-Based Transient Surface Acceleration of Thermoelastic Layers

    NASA Astrophysics Data System (ADS)

    CETINKAYA, CETIN; WU, CUNLI; LI, CHEN

    2000-03-01

    The removal of particles from elastic substrates has been an important practical problem in the electronics industry especially as the sizes of electronic units shrink. In recent years, there has been an interest in removingsubmicron level particles from surfaces. The use of traditional surface cleaning methods, such as ultrasonically induced fluid flow, vibrational methods, centrifugal techniques, is limited to particles that require surface acceleration lower than 107m/s2. For the effective removal of submicron particles, a higher level surface acceleration is needed since the adhesion forces (mainly van der Waals force for dry surfaces) are related to the particle size and increase approximately linearly as the characteristic radius of small particles that are to be removed decreases. In current work, based on the generalized dynamic theory of thermoelasticity reported, a transfer matrix formulation including the second sound effect is developed for a thermoelastic layer. The transfer matrix for axisymmetric wave propagation in a thermoelastic layer is obtained by adopting a double integral transform approach. The second sound effect is included to eliminate the thermal wave travelling with infinite velocity as predicted by the diffusion heat transfer model, and, consequently, the immediate arrival of waves. Using the current formulation and the periodic systems framework, a transfer function formulation for calculating the accelerations is developed for transient analysis. A double integral transform inversion method is used for transient response calculations. Acceleration levels, sufficient for submicron particle removal, are reported. Various processes such as thermoelastic stresses, surface evaporation, and optical breakdown may be responsible for surface acceleration components and particle removal. In current work, only the surface acceleration due to transient thermoelastic wave propagation is under investigation.

  17. Double-bracket dissipation in kinetic theory for particles with anisotropic interactions

    Microsoft Academic Search

    Darryl D. Holm; Vakhtang Putkaradze; Cesare Tronci

    2010-01-01

    We derive equations of motion for the dynamics of anisotropic particles\\u000adirectly from the dissipative Vlasov kinetic equations, with the dissipation\\u000agiven by the double bracket approach (Double Bracket Vlasov, or DBV). The\\u000amoments of the DBV equation lead to a nonlocal form of Darcy's law for the mass\\u000adensity. Next, kinetic equations for particles with anisotropic interaction are\\u000aconsidered

  18. Dye-enhanced laser fluorescence detection of caries lesions around brackets

    Microsoft Academic Search

    Cássio José Fornazari Alencar; Mariana Minatel Braga; Elisabeth de Oliveira; José Nicolau; Fausto Medeiros Mendes

    2009-01-01

    The aim was to evaluate the performance of DIAGNOdent [laser fluorescence(LF) and LFpen] devices enhanced by fluorescent dye\\u000a in detecting mineral loss around brackets and comparing the inhibitory effect of bonding material on artificial demineralization,\\u000a and to verify whether LF methods show the same trends of mineral loss. Brackets were bonded to premolar halves with Fuji Ortho\\u000a LC, Transbond XT,

  19. Bracket Gamma, Molecular Hydrogen, and Singly-Ionized Iron in GGD 37 (Cep A West)

    Microsoft Academic Search

    S. N. Raines; D. M. Watson; W. J. Forrest; J. L. Pipher; G. Delamarter; C. E. Woodward; T. Hodge; M. A. Greenhouse; H. A. Smith; S. Satyapal; J. Fischer; K. L. Thompson; J. Muzerolle

    1996-01-01

    We present near-infrared images of the Herbig-Haro objects in GGD 37 in the 2.166 mu m hydrogen recombination line Bracket gamma (R = 70), molecular hydrogen, v = 1 - 0 S(1), 2.122 mu m line, (R = 70), and in the forbidden ionized iron 1.644 mu m line, (R = 800). The Bracket gamma emission appears as a knot

  20. Comparison of Surface Plasmon Resonance and Localized Surface Plasmon Resonance-based optical fibre sensors

    NASA Astrophysics Data System (ADS)

    Cao, J.; Galbraith, E. K.; Sun, T.; Grattan, K. T. V.

    2011-08-01

    In this work, two of surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR)-based optical fibre sensors have been successfully developed and cross-compared. With one SPR sensor being coated with a thin layer of gold film and the other gold-nanorods (GNRs), forming a LSPR sensor, both sensors are subjected to various refractive index changes. As a result their sensitivities are measured in the form of resonance wavelength shift as a function of refractive index variation. The results demonstrate that the thin-film coated SPR sensor has much higher sensitivity than that of GNRs coated LSPR sensor but with worse linearity.

  1. Effect of Argon Laser on Enamel Demineralization around Orthodontic Brackets: An In Vitro Study

    PubMed Central

    Miresmaeili, Amirfarhang; Etrati Khosroshahi, Mohammad; Motahary, Pouya; Rezaei-Soufi, Loghman; Mahjub, Hossein; Dadashi, Maryam; Farhadian, Nasrin

    2014-01-01

    Objective This study was designed to evaluate the effect of argon laser irradiation on development and progress of enamel demineralization around orthodontic brackets. Materials and Methods: Fifty caries-free, intact human premolars were randomly assigned to one of the following five equal groups: Groups 1 (control) and 2: The brackets were bonded using conventional halogen light for 40s and argon laser for 10s, respectively. Teeth in group 3 were lased with argon laser for 10s before bracket bonding with halogen light. Group 4 was the same as group 3 except that brackets were also bonded with argon laser. In group 5 samples were bonded conventionally, immersed in an artificial caries solution for two days and then irradiated for 10s with argon laser. All samples were subjected to demineralization by artificial caries solution for 10 days. After bracket removal, samples were buccolingually sectioned and evaluated by polarized light microscopy. Decalcified lesion depth in each section was measured by a trained examiner in a blind fashion. Data were analyzed in SPSS 14 using one-way ANOVA and Tukey’s HSD post hoc test. Results: The control group showed the greatest mean lesion depth while group 5 revealed the lowest. The laser-treated groups had significantly lower mean lesion depth compared with the control group (P<0.05) except for group 4 (P=0.192). Conclusion: Argon laser irradiation for 10s before or during bracket bonding can increase caries resistance of intact and demineralized enamel. PMID:25584052

  2. Development of an integrated capillary valve-based preconcentrator and surface-based immunoassay

    E-print Network

    Liu, Vincent Hok

    2009-01-01

    A new generation of integrated preconcentrator and immunoassay was developed. A novel, self-aligned method for patterning Nafion resin was developed and applied to create a preconcentrator. In a parallel effort, a surface-based ...

  3. Optical triangulation-based microtopographic inspection of surfaces.

    PubMed

    Costa, Manuel F M

    2012-01-01

    The non-invasive inspection of surfaces is a major issue in a wide variety of industries and research laboratories. The vast and increasing range of surface types, tolerance requirements and measurement constraints demanded during the last decades represents a major research effort in the development of new methods, systems and metrological strategies. The discreet dimensional evaluation the rugometric characterization and the profilometric inspection seem to be insufficient in many instances. The full microtopographic inspection has became a common requirement. Among the different systems developed, optical methods have the most important role and among those triangulation-based ones have gained a major status thanks to their flexibility, reliability and robustness. In this communication we will provide a brief historical review on the development of optical triangulation application to the dimensional inspection of objects and surfaces and on the work done at the Microtopography Laboratory of the Physics Department of the University of Minho, Portugal, in the development of methods and systems of optical triangulation-based microtopographic inspection of surfaces. PMID:22666036

  4. Roughness-Based Superhydrophobic Surfaces: Fundamentals and Future Directions

    NASA Astrophysics Data System (ADS)

    Patankar, Neelesh

    2011-11-01

    Superhydrophobicity of rough surfaces has attracted global interest through the past decade. There are naturally occurring instances of such surfaces, e.g., lotus leaves, which led to the popular term ``lotus effect.'' Numerous applications in wide ranging areas such as drag reduction, self-cleaning, heat exchangers, energy conversion, condensation, anti-icing, textile, desalination, etc., are being explored by researchers worldwide. The signature configuration for superhydrophobicity has been ``bead-like'' drops on rough surfaces that roll-off easily. This becomes possible if the liquid does not impale the roughness grooves, and if the contact angle hysteresis is low. Finding appropriate surface roughness is therefore necessary. A thermodynamic framework to enable analysis of this problem will be presented. It will be noted that the success of rough superhydrophobic substrates relies on the presence of gas pockets in the roughness grooves underneath the liquid. These gas pockets could be those of air from the surrounding environment. Current design strategies rely on the availability of air. However, if the rough substrates are fully submerged in the liquid then the trapped air in the roughness grooves may not be sustained. A design approach based on sustaining a vapor phase of the liquid itself in the roughness grooves, instead of relying on the presence of air, will be presented. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling at dramatically low superheats, among others. The concept can be generalized to other transitions on the phase diagram, thus enabling the design of rough surfaces for phase manipulation in general.

  5. Surface recrystallization of a single crystal nickel-base superalloy

    NASA Astrophysics Data System (ADS)

    Meng, Jie; Jin, Tao; Sun, Xiao-Feng; Hu, Zhuang-Qi

    2011-04-01

    The recrystallization behavior of a single crystal nickel-base superalloy was investigated by shot peening and subsequent annealing. Two kinds of recrystallization microstructures, which are intensively dependent on the annealing temperature, are shown in the nickel-base superalloy after shot peening and subsequent annealing. Surface recrystallized grains are obtained when the superalloy is annealed at solution treatment temperature. The nucleation of recrystallization originates from the dendritic core, where rapid dissolution of ?' particles occurs. Cellular recrystallization is observed after annealing at lower temperatures. Cellular structures induced by high diffusivity of the moving boundary and more ?' particles dissolution led by residual stress are developed from the surface region. Recrystallized kinetics of the shot-peened alloy annealed at 1050°C accords with the Johnson-Mehl-Avrami-Kolmogorov equation. The low Avrami exponent is caused by the inhomogeneous distribution of stored energy, the decreasing of stored energy during recovery, and the strong resistance of boundary migration by ?' particles.

  6. Lunar surface roughness based on multiscale morphological method

    NASA Astrophysics Data System (ADS)

    Cao, Wei; Cai, Zhanchuan; Tang, Zesheng

    2015-04-01

    Surface roughness is a useful tool to reflect numerous geological characteristics. Lunar Orbiter Laser Altimeter (LOLA) Gridded Data Records (GDRs) are used as the datum. In this paper, Lunar surface roughness maps are built based on morphological methods in image processing. As roughness measure, elevations of GDRs are considered as pixels of an image. Structuring element (SE) is employed as a scale-dependent measure of roughness maps. Global roughness maps with different resolutions are built to interpret the stability of our roughness measure. Global roughness with different-size SEs is mapped based on GDRs with the resolution of 64 pixels per degree to discuss the roughness variations in local regions determined by SEs. Regional roughness maps provide significant melt-related overviews of typical topography.

  7. An algorithm for restoring the wafer surface based on B-spline surface reconstruction

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Jiang, Wei; Yan, Wei; Hu, Song

    2013-08-01

    Project lithography has experienced the development of contact, stepper, and step and scan lithography machine. Currently lithography machine has entered the age of twinscan lithography machine. The twinscan lithography machine took advantages of high efficiency and good compatibility, but the focal depth of twinscan lithography machine was only in the nanometer range. In order to guarantee the quality of the exposure, the twinscan lithography machine put forward high request for detecting the map of the wafer surface. Usually, the uniform sampling method and the whole map rebuilding method were used to detect the map of the silicon wafer surface, which is a main cause for the data redundancy. On the other hand, the map reconstructed by this means was not smooth which caused the motor of lithography machine can't response. To avoid these disadvantages, an algorithm for restoring the wafer surface based on B-spline surface reconstruction is proposed in this paper. This method is able to satisfy requirements for the local adaptive refinement, which effectively avoid data redundancy. This method is robust, which means the effect of solving nonlinear problems and inhibiting fuzzy noise is remarkable. The surface reconstructed by this new method is very smooth, which is more suitable for the movement of the motor in lithography machine.

  8. AUTOMATIC MARS LANDING SITE MAPPING USING SURFACE-BASED IMAGES

    Microsoft Academic Search

    Ron Li; Kaichang Di; Fengliang Xu

    2003-01-01

    This paper presents techniques for automatic mapping of Mars landing sites using surface-based images, i.e., those taken by Mar s landers and\\/or rovers. An innovative method for automatic tie point selection is presented that includes five steps: interest p oint extraction, interest point matching, parallax verification, gra ph consistency verification and final tie point selection with g ridding. In matching

  9. Fourier-Based Inspection of Free-Form Reflective Surfaces

    Microsoft Academic Search

    Y. Caulier; S. Bourennane

    2008-01-01

    A general free-form surface inspection approach relying on the projection of a structured light pattern and the interpretation\\u000a of the generated stripe structures by means of Fourier-based features is proposed in this paper.\\u000a \\u000a The major concerns of this paper are the determination of various refrence sets of stripe patterns, and the detailed investigation\\u000a on the subset of Fourier features that

  10. Operational Satellite-based Surface Oil Analyses (Invited)

    Microsoft Academic Search

    D. Streett; C. Warren

    2010-01-01

    During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible\\/near

  11. Photonic bandgap fiber-based Surface Plasmon Resonance sensors.

    PubMed

    Gauvreau, Bertrand; Hassani, Alireza; Fassi Fehri, Majid; Kabashin, Andrei; Skorobogatiy, Maksim A

    2007-09-01

    The concept of photonic bandgap fiber-based surface plasmon resonance sensor operating with low refractive index analytes is developed. Plasmon wave on the surface of a thin metal film embedded into a fiber microstructure is excited by a leaky Gaussian-like core mode of a fiber. We demonstrate that by judicious design of the photonic crystal reflector, the effective refractive index of the core mode can be made considerably smaller than that of the core material, thus enabling efficient phase matching with a plasmon, high sensitivity, and high coupling efficiency from an external Gaussian source, at any wavelength of choice from the visible to near-IR. To our knowledge, this is not achievable by any other traditional sensor design. Moreover, unlike the case of total internal reflection waveguide-based sensors, there is no limitation on the upper value of the waveguide core refractive index, therefore, any optical materials can be used in fabrication of photonic bandgap fiber-based sensors. Based on numerical simulations, we finally present designs using various types of photonic bandgap fibers, including solid and hollow core Bragg fibers, as well as honeycomb photonic crystal fibers. Amplitude and spectrum based methodologies for the detection of changes in the analyte refractive index are discussed. Furthermore, sensitivity enhancement of a degenerate double plasmon peak excitation is demonstrated for the case of a honeycomb fiber. Sensor resolutions in the range 7 * 10(-6) -5 * 10(-5) RIU were demonstrated for an aqueous analyte. PMID:19547499

  12. Surface-based registration of liver in ultrasound and CT

    NASA Astrophysics Data System (ADS)

    Dehghan, Ehsan; Lu, Kongkuo; Yan, Pingkun; Tahmasebi, Amir; Xu, Sheng; Wood, Bradford J.; Abi-Jaoudeh, Nadine; Venkatesan, Aradhana; Kruecker, Jochen

    2015-03-01

    Ultrasound imaging is an attractive modality for real-time image-guided interventions. Fusion of US imaging with a diagnostic imaging modality such as CT shows great potential in minimally invasive applications such as liver biopsy and ablation. However, significantly different representation of liver in US and CT turns this image fusion into a challenging task, in particular if some of the CT scans may be obtained without contrast agents. The liver surface, including the diaphragm immediately adjacent to it, typically appears as a hyper-echoic region in the ultrasound image if the proper imaging window and depth setting are used. The liver surface is also well visualized in both contrast and non-contrast CT scans, thus making the diaphragm or liver surface one of the few attractive common features for registration of US and non-contrast CT. We propose a fusion method based on point-to-volume registration of liver surface segmented in CT to a processed electromagnetically (EM) tracked US volume. In this approach, first, the US image is pre-processed in order to enhance the liver surface features. In addition, non-imaging information from the EM-tracking system is used to initialize and constrain the registration process. We tested our algorithm in comparison with a manually corrected vessel-based registration method using 8 pairs of tracked US and contrast CT volumes. The registration method was able to achieve an average deviation of 12.8mm from the ground truth measured as the root mean square Euclidean distance for control points distributed throughout the US volume. Our results show that if the US image acquisition is optimized for imaging of the diaphragm, high registration success rates are achievable.

  13. [Tip-Edge Plus bracket--a combination between Begg and Straight-Wire bracket--the best of both worlds with new horizons in fixed orthodontic therapy].

    PubMed

    Meyer, Rudolf

    2008-01-01

    The Tip-Edge bracket was invented by Dr. P.C. Kesling (La Porte, Indiana, U.S.A.) in 1986. It introduced differential tooth movement within a modified Straight-Wire bracket system. The new Tip-Edge Plus bracket, first introduced in 2003, now uses superelastic Ni-Ti archwires (Deep Tunnel or Uprighting Wires) in Stage III instead of the Side-Winder springs for tip and torque. With Tip-Edge Plus, the average treatment time for extraction and non-extraction cases is 16 months, with 4 to 6 main archwires. Headgear, bite turbos and mini-implants are not required. The comfort for the patient and operator is increased, with less adjustments and shorter treatment time, resulting in a zero tolerance finish. This is because of the unique bracket architecture, which allows controlled tipping in one direction, while boosting anchorage in the other, with three-dimensional root control at the finish. Tip-Edge Plus Orthodontics is the fixed appliance of the 21st century and is in the education programmes of more than 55 dental shools worldwide. PMID:18800564

  14. Standing surface acoustic wave (SSAW)-based microfluidic cytometer

    PubMed Central

    Chen, Yuchao; Nawaz, Ahmad Ahsan; Zhao, Yanhui; Huang, Po-Hsun; McCoy, J. Phillip; Levine, Stewart; Wang, Lin; Huang, Tony Jun

    2014-01-01

    The development of microfluidic chip-based cytometers has become an important area due to their advantages of compact size and low cost. Herein, we demonstrate a sheathless microfluidic cytometer which integrates a standing surface acoustic wave (SSAW)-based microdevice capable of 3D particle/cell focusing with a laser-induced fluorescence (LIF) detection system. Using SSAW, our microfluidic cytometer was able to continuously focus microparticles/cells at the pressure node inside a microchannel. Flow cytometry was successfully demonstrated using this system with a coefficient of variation (CV) of less than 10% at a throughput of ~1000 events/s when calibration beads were used. We also demonstrated that fluorescently labeled human promyelocytic leukemia cells (HL-60) could be effectively focused and detected with our SSAW-based system. This SSAW-based microfluidic cytometer did not require any sheath flows or complex structures, and it allowed for simple operation over a wide range of sample flow rates. Moreover, with the gentle, bio-compatible nature of low-power surface acoustic waves, this technique is expected to be able to preserve the integrity of cells and other bioparticles. PMID:24406848

  15. Microwave-assisted hydrothermally grown epitaxial ZnO films on Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket MgAl{sub 2}O{sub 4} substrate

    SciTech Connect

    Liew, Laura-Lynn [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link Singapore 117602 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore); Le, Hong Quang, E-mail: lehq@imre.a-star.edu.sg [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link Singapore 117602 (Singapore); Goh, Gregory K.L. [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR), 3 Research Link Singapore 117602 (Singapore); School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore)

    2012-05-15

    In this report, epitaxial ZnO films were grown on Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket MgAl{sub 2}O{sub 4} single crystal substrates using Microwave Assisted Hydrothermal (MAH) method with microwave radiation heating (2.45 GHz) at 90 Degree-Sign C in a short time (within 15 min). Scanning electron microscopy confirms that these films possess smooth surface morphology with fully coalesced grains. In addition, photoluminescence (PL) measurements exhibit strong ultraviolet emission at room temperature, indicating potential applications for short-wave light-emitting photonic devices. The PL properties were improved by a thermal annealing process without generating structural defects. Hall measurements after thermal treatment show the carrier concentration to be of the order of 10{sup 19} cm{sup -3} which is comparable to those grown by conventional solution methods. The MAH method will offer a rapid route to synthesize epitaxial ZnO films with good optical and electrical properties for various applications. - Graphical abstract: FESEM images showing the morphology and cross sectional view of ZnO films grown using microwave assisted hydrothermal method at 90 Degree-Sign C for 30 min. Highlights: Black-Right-Pointing-Pointer Microwave Assisted Hydrothermal (MAH) method was introduced to synthesize epitaxial ZnO films. Black-Right-Pointing-Pointer The films possess smooth surface morphology, fully coalesced grains with high optical properties. Black-Right-Pointing-Pointer It exhibit good electrical properties (carrier concentration 10{sup 19} cm{sup -3}, mobility 19 cm{sup 2}/Vs).

  16. Continuum limit of the Volterra model, separation of variables and non standard realizations of the Virasoro Poisson bracket

    E-print Network

    Olivier Babelon

    2006-03-21

    The classical Volterra model, equipped with the Faddeev-Takhtadjan Poisson bracket provides a lattice version of the Virasoro algebra. The Volterra model being integrable, we can express the dynamical variables in terms of the so called separated variables. Taking the continuum limit of these formulae, we obtain the Virasoro generators written as determinants of infinite matrices, the elements of which are constructed with a set of points lying on an infinite genus Riemann surface. The coordinates of these points are separated variables for an infinite set of Poisson commuting quantities including $L\\_0$. The scaling limit of the eigenvector can also be calculated explicitly, so that the associated Schroedinger equation is in fact exactly solvable.

  17. Surface sensitivity of straight long-range surface plasmon waveguides for attenuation-based biosensing

    NASA Astrophysics Data System (ADS)

    Wong, Wei Ru; Mahamd Adikan, Faisal Rafiq; Berini, Pierre

    2014-08-01

    The sensing performance of straight long-range surface plasmon waveguides consisting of a thin gold stripe embedded in Cytop is explored theoretically as a function of the metal stripe cross-sectional dimensions and the length of the sensing channel, and as a function of the sensing medium refractive index. The surface sensitivity and detection limit of such waveguides for attenuation-based biosensing are assessed. We find that changes in coupling efficiency between the sensing waveguide and the access waveguides, and changes in attenuation constant, due to adlayer formation, can contribute additively to the sensing performance. We observed a trade-off between the insertion loss and the change in insertion loss occurring during sensing. Optimum designs leading to compact, sensitive, and cost-effective biosensors are reported.

  18. Randomized controlled clinical trial of oral health-related quality of life in patients wearing conventional and self-ligating brackets

    PubMed Central

    Mansor, Noorhanizar; Saub, Roslan

    2014-01-01

    Objective The aim of this randomized controlled clinical trial was to compare oral health-related quality of life (OHRQoL) of patients treated with conventional, active self-ligating (ASL), and passive self-ligating (PSL) brackets in different therapeutic phases. Methods Sixty patients (mean age 18.3 years; 29 males and 31 females) requiring orthodontic treatment were randomly and equally assigned to receive conventional (Victory Series), ASL (In-Ovation R), or PSL (Damon 3MX) brackets. OHRQoL was measured with a self-administered modified 16-item Malaysian version of the Oral Health Impact Profile for immediate (soon after the visit) and late (just before the subsequent visit) assessments of the bonding and activation phases. Data were analyzed with the Kruskal-Wallis and chi-square tests. Results The PSL and ASL groups showed more immediate and late impacts in the bonding phase, respectively; the conventional group was affected in both the assessments. The first activation phase had similar impacts in the groups. After the second activation, the conventional group showed more immediate impacts, whereas the PSL and ASL groups had more late impacts. The commonly affected domains were "physical disability," "functional limitation," "physical pain," and "psychological discomfort." No significant differences in the prevalence and severity of immediate and late impacts on OHRQoL of the patients were noted in any therapeutic phase. Conclusions No bracket system seems to ensure superior OHRQoL. This information could be useful for explaining the therapeutic phases, especially the initial one, and selecting the optimal bracket system based on the patient's preference. PMID:25133131

  19. An Ab Initio Based Potential Energy Surface for Water

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

  20. A comparison of volume-based and surface-based multi-voxel pattern analysis.

    PubMed

    Oosterhof, Nikolaas N; Wiestler, Tobias; Downing, Paul E; Diedrichsen, Jörn

    2011-05-15

    For functional magnetic resonance imaging (fMRI), multi-voxel pattern analysis (MVPA) has been shown to be a sensitive method to detect areas that encode certain stimulus dimensions. By moving a searchlight through the volume of the brain, one can continuously map the information content about the experimental conditions of interest to the brain. Traditionally, the searchlight is defined as a volume sphere that does not take into account the anatomy of the cortical surface. Here we present a method that uses a cortical surface reconstruction to guide voxel selection for information mapping. This approach differs in two important aspects from a volume-based searchlight definition. First, it uses only voxels that are classified as grey matter based on an anatomical scan. Second, it uses a surface-based geodesic distance metric to define neighbourhoods of voxels, and does not select voxels across a sulcus. We study here the influence of these two factors onto classification accuracy and onto the spatial specificity of the resulting information map. In our example data set, participants pressed one of four fingers while undergoing fMRI. We used MVPA to identify regions in which local fMRI patterns can successfully discriminate which finger was moved. We show that surface-based information mapping is a more sensitive measure of local information content, and provides better spatial selectivity. This makes surface-based information mapping a useful technique for a data-driven analysis of information representation in the cerebral cortex. PMID:20621701

  1. Computational view of surface based organic mass spectrometry.

    PubMed

    Garrison, Barbara J; Postawa, Zbigniew

    2008-01-01

    Surface based mass spectrometric approaches fill an important niche in the mass analysis portfolio of tools. The particular niche depends on both the underlying physics and chemistry of molecule ejection as well as experimental characteristics. In this article, we use molecular dynamics computer simulations to elucidate the fundamental processes giving rise to ejection of organic molecules in atomic and cluster secondary ion mass spectrometry (SIMS), massive cluster impact (MCI) mass spectrometry, and matrix-assisted laser desorption ionization (MALDI) mass spectrometry. This review is aimed at graduate students and experimental researchers. PMID:18421766

  2. Small reactor power systems for manned planetary surface bases

    SciTech Connect

    Bloomfield, H.S.

    1987-12-01

    A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.

  3. Remote surface water monitoring radio based telemetry system

    NASA Astrophysics Data System (ADS)

    Goodwin, W. L.; Baxter, D.

    1993-02-01

    The Environmental Protection Department of EG&G Rocky Flats has designed and developed a unique Remote Surface Water Monitoring System using radio telemetry hardware and computer control software. The system is based on new technologies in microelectronics and environmental monitoring sensors. An engineering team, headed up by the Surface Water Division at EG&G, has proven that with careful evaluation of new technologies and hardware components, a reliable, cost effective and graphical user interface (GUI) system can be designed and installed. The network utilizes standard industrial control hardware and off-the-shelf components in order to meet several time requirements outlined by an Interagency Agreement (IAG) between the Department of Energy, the U.S. Environmental Protection Agency, and state and local authorities. In addition, the system had to meet tight environmental specifications and procedures. The Rocky Flats Plant is part of the U.S. Department of Energy Weapons Complex and is located near the Denver metropolitan area. The plant is required by law, and Interagency Agreement, to maintain strict environmental standards for surface water monitoring and discharge characteristics, including the requirement for utilization of best available technology.

  4. Subwavelength surface plasmons based on novel structures and metamaterials

    NASA Astrophysics Data System (ADS)

    Yang, Ruoxi

    With the rapid development of nanofabrication technology and powerful computational tools over the last decade, nanophotonics has enjoyed tremendous innovation and found wide applications in ultrahigh-speed data transmission, sensitive optical detection, manipulation of ultra-small objects, and visualization of nanoscale patterns. Surface plasmon-based photonics (or plasmonics) merges electronics and photonics at the nanoscale, creating the ability to combine the superior technical advantages of photonics and electronics on the same chip. Plasmonics focuses on the innovation of photonic devices by exploiting the optical property of metals. In particular, the oscillation of free electrons, when properly driven by electromagnetic waves, would form plasmon-polaritons in the vicinity of a metal surface and potentially result in extreme light confinement, which may beat the diffraction limit faced by conventional photonic devices and enable greatly enhanced light-matter interactions at the deep subwavelength scale. The objective of this dissertation is to develop subwavelength or deep subwavelength plasmonic waveguides and explore their integration on conventional dielectric platforms for multiple applications. Three novel structures (or mechanisms) are employed to develop and integrate nanoplasmonic waveguides; each consists of one part of the dissertation. The first part of this dissertation covers the design, fabrication, and demonstration of two-dimensional and three-dimensional metal-insulator-metal plasmonic couplers for mode transformation between photonic and nanoplasmonic domains on the silicon-on-insulator platform. In particular, deep subwavelength plasmonic modes under 100-nm are achieved via end-fire coupling and adiabatic mode transformation at telecom wavelengths. The second part studies metallic gratings as spoof plasmonic waveguides hosting deep subwavelength surface propagation modes. Metallic gratings under different dielectric coatings are numerically investigated for terahertz and gigahertz regions. The third part proposes, explores, and experimentally demonstrates the "metametal" for super surface wave excitation based on multilayered metal-insulator stacks, where the dispersion of the supported surface modes can be engineered by insulator dopant films in a given metal. The final part discusses the potential applications of active plasmonics for optical sensing, modulation and photovoltaics.

  5. Determination of DNA based on localized surface plasmon resonance.

    PubMed

    Bi, Ning; Sun, Ying; Zhang, Hanqi; Song, Daqian; Wang, Liying; Wang, Jian; Tian, Yuan

    2010-11-01

    A resonance light scattering (RLS) spectrometry for determining DNA based on localized surface plasmon resonance (LSPR) of gold nanorods was developed. The fabrication and characterization of the biosensor utilized gold nanorods as the optical transducer was described. The DNA was determined based on the binding of DNA to gold nanorods by electrostatic adsorption. The RLS intensity of the gold nanorods was enhanced in the presence of DNA. The peaks of the enhanced RLS spectrum were at the wavelength 311 and 581 nm. The binding of DNA to the gold nanorods causes an increase of the RLS intensity that is responsive to the concentration of DNA. Under the optimal conditions, the enhanced RLS intensities are directly proportional to the DNA concentrations in the range of 0.05-0.5 microg/mL. The proposed method was successfully applied to the determination of DNA in the samples and the results were satisfactory. PMID:20667435

  6. Imaging Layers Based on Surface-Initiated Polymers

    NASA Astrophysics Data System (ADS)

    Montague, Martha; Edwards, Erik; Nealey, Paul

    2002-03-01

    Photoresist structures at the 70 nm and 50 nm technology nodes are of molecular dimensions, and allowable tolerances and margins are of atomic dimensions. It is unclear whether current resist processing based on preferential solubility of protected or deprotected polymer molecules in aqueous base will afford the necessary process latitude at this scale. We are developing thin film imaging materials (100 to 200 nm thick) composed of polymer chains that are grafted (polymerized) directly on the surface of the substrate. These brushes have been grown from silicon wafers using "living" free radical initiators that are tethered to the surface of the wafer. We pattern this system by taking advantage of chemical amplification. An acid-labile linkage was incorporated into the tether of the polymer brush, and by using a photo acid generator we can create acid in exposed regions of our imaging layer. This strategy allows us to decouple the imaging process from the chemistry of the polymer. The resist then can be designed to optimize properties such as transparency and etch resistance. We will evaluate the imaging layers for process latitude and resolution.

  7. Surface modification of nickel based alloys for improved oxidation resistance

    SciTech Connect

    Jablonski, Paul D.; Alman, David E.

    2005-02-01

    The present research is aimed at the evaluation of a surface modification treatment to enhance the high temperature stability of nickel-base superalloys. A low Coefficient Thermal Expansion (CTE ~12.5x10-6/°C) alloy based on the composition (in weight %) of Ni-22Mo-12.5Cr was produced by Vacuum Induction Melting and Vacuum Arc Melting and reduced to sheet by conventional thermal-mechanical processing. A surface treatment was devised to enhance the oxidation resistance of the alloys at high temperature. Oxidation tests (in dry and wet air; treated and untreated) were conducted 800°C to evaluate the oxidation resistance of the alloys. The results were compared to the behavior of Haynes 230 (Ni-22Cr) in the treated and untreated conditions. The treatment was not very effective for Haynes 230, as this alloy had similar oxidation behavior in both the treated and untreated conditions. However, the treatment had a significant effect on the behavior of the low CTE alloy. At 800°C, the untreated Ni-12.5Cr alloy was 5 times less oxidation resistant than Haynes 230. However, in the treated condition, the Ni-12.5Cr alloy had comparable oxidation resistance to the Haynes 230 alloy.

  8. The Jacobiator of Nonholonomic Systems and the Geometry of Reduced Nonholonomic Brackets

    NASA Astrophysics Data System (ADS)

    Balseiro, Paula

    2014-11-01

    In this paper, we consider the Hamiltonian formulation of nonholonomic systems with symmetries and study several aspects of the geometry of their reduced almost Poisson brackets, including the integrability of their characteristic distributions. Our starting point is establishing global formulas for the nonholonomic Jacobiators, before and after reduction, which are used to clarify the relationship between reduced nonholonomic brackets and twisted Poisson structures. For certain types of symmetries (generalizing the Chaplygin case), we obtain genuine Poisson structures on the reduced spaces and analyze situations in which the reduced nonholonomic brackets arise by applying a gauge transformation to these Poisson structures. We illustrate our results with mechanical examples, and in particular show how to recover several well-known facts in the special case of Chaplygin symmetries.

  9. The Jacobiator of nonholonomic systems and the geometry of reduced nonholonomic brackets

    E-print Network

    Paula Balseiro

    2014-09-01

    In this paper, we consider the hamiltonian formulation of nonholonomic systems with symmetries and study several aspects of the geometry of their reduced almost Poisson brackets, including the integrability of their characteristic distributions. Our starting point is establishing global formulas for the nonholonomic Jacobiators, before and after reduction, which are used to clarify the relationship between reduced nonholonomic brackets and twisted Poisson structures. For certain types of symmetries (generalizing the Chaplygin case), we obtain genuine Poisson structures on the reduced spaces and analyze situations in which the reduced nonholonomic brackets arise by applying a gauge transformation to these Poisson structures. We illustrate our results with mechanical examples, and in particular show how to recover several well-known facts in the special case of Chaplygin symmetries.

  10. Characterizing a New Surface-Based Shortwave Cloud Retrieval Technique, Based on Transmitted Radiance for Soil and Vegetated Surface Types

    NASA Technical Reports Server (NTRS)

    Coddington, Odele; Pilewskie, Peter; Schmidt, K. Sebastian; McBride, Patrick J.; Vukicevic, Tomislava

    2013-01-01

    This paper presents an approach using the GEneralized Nonlinear Retrieval Analysis (GENRA) tool and general inverse theory diagnostics including the maximum likelihood solution and the Shannon information content to investigate the performance of a new spectral technique for the retrieval of cloud optical properties from surface based transmittance measurements. The cumulative retrieval information over broad ranges in cloud optical thickness (tau), droplet effective radius (r(sub e)), and overhead sun angles is quantified under two conditions known to impact transmitted radiation; the variability in land surface albedo and atmospheric water vapor content. Our conclusions are: (1) the retrieved cloud properties are more sensitive to the natural variability in land surface albedo than to water vapor content; (2) the new spectral technique is more accurate (but still imprecise) than a standard approach, in particular for tau between 5 and 60 and r(sub e) less than approximately 20 nm; and (3) the retrieved cloud properties are dependent on sun angle for clouds of tau from 5 to 10 and r(sub e) less than 10 nm, with maximum sensitivity obtained for an overhead sun.

  11. Detecting Nasal Vowels in Speech Interfaces Based on Surface Electromyography

    PubMed Central

    Freitas, João; Teixeira, António; Silva, Samuel; Oliveira, Catarina; Dias, Miguel Sales

    2015-01-01

    Nasality is a very important characteristic of several languages, European Portuguese being one of them. This paper addresses the challenge of nasality detection in surface electromyography (EMG) based speech interfaces. We explore the existence of useful information about the velum movement and also assess if muscles deeper down in the face and neck region can be measured using surface electrodes, and the best electrode location to do so. The procedure we adopted uses Real-Time Magnetic Resonance Imaging (RT-MRI), collected from a set of speakers, providing a method to interpret EMG data. By ensuring compatible data recording conditions, and proper time alignment between the EMG and the RT-MRI data, we are able to accurately estimate the time when the velum moves and the type of movement when a nasal vowel occurs. The combination of these two sources revealed interesting and distinct characteristics in the EMG signal when a nasal vowel is uttered, which motivated a classification experiment. Overall results of this experiment provide evidence that it is possible to detect velum movement using sensors positioned below the ear, between mastoid process and the mandible, in the upper neck region. In a frame-based classification scenario, error rates as low as 32.5% for all speakers and 23.4% for the best speaker have been achieved, for nasal vowel detection. This outcome stands as an encouraging result, fostering the grounds for deeper exploration of the proposed approach as a promising route to the development of an EMG-based speech interface for languages with strong nasal characteristics. PMID:26069968

  12. Engineering aperiodic nanostructured surfaces for scattering-based optical devices

    NASA Astrophysics Data System (ADS)

    Lee, Yuk Kwan Sylvanus

    Novel optical devices such as biosensors, color displays and authentication devices can be obtained from the distinctive light scattering properties of resonant nanoparticles and nanostructured arrays. These arrays can be optimized through the choice of material, particle morphology and array geometry. In this thesis, by engineering the multi-frequency colorimetric responses of deterministic aperiodic nanostructured surfaces (DANS) with various spectral Fourier properties, I designed, fabricated and characterized scattering-based devices for optical biosensing and structural coloration applications. In particular, using analytical and numerical optimization, colorimetric biosensors are designed and fabricated with conventional electron beam lithography, and characterized using dark-field scattering imaging as well as image autocorrelation analysis of scattered intensity in the visible spectral range. These sensors, which consist of aperiodic surfaces ranging from quasi-periodic to pseudo-random structures with flat Fourier spectra, sustain highly complex structural resonances that enable a novel optical sensing approach beyond the traditional Bragg scattering. To this end, I have experimentally demonstrated that DANS with engineered structural colors are capable of detecting nanoscale protein monolayers with significantly enhanced sensitivity over periodic structures. In addition, different aperiodic arrays of gold (Au) nanoparticles are integrated with polydimethylsiloxane (PDMS) microfluidic structures by soft-lithographic micro-imprint techniques. Distinctive scattering spectral shifts and spatial modifications of structural color patterns in response to refractive index variations were simultaneously measured. The successful integration of DANS with microfluidics technology has introduced a novel opto-fluidic sensing platform for label-free and multiplexed lab-on-a-chip applications. Moreover, by studying the isotropic scattering properties of homogenized Pinwheel aperiodic arrays, angle-insensitive (i.e. isotropic) coloration from nanostructured metal surfaces can be designed and optimized without randomization. Pinwheel nanoparticle arrays on a gold thin film were fabricated for the first time and investigated using dark-field scattering and angle-resolved reflectivity measurements. In sharp contrast to the colorimetric responses of periodically nanopatterned surfaces, which strongly depend on the observation angle, spatially uniform and isotropic green coloration of gold films were demonstrated using these engineered metal surfaces. In addition, the intensity of the scattered light is enhanced by plasmonic resonance originated from gold nanoparticles deposited on the gold substrates. The development of the enhanced isotropic scattering devices could advance plasmonic applications to color display, optical tagging and colorimetric sensing technologies.

  13. Volcanic rifts bracketing volcanoes: an analogue answer to an old unsolved problem

    NASA Astrophysics Data System (ADS)

    Mussetti, Giulio; van Wyk de Vries, Benjamin; Corti, Giacomo; Hagos, Miruts

    2015-04-01

    It has been observed in Central America that many volcanoes have volcanic alignments and faults at their east and west feet. A quick look at many rifts indicates that this also occurs elsewhere. While this feature has been noted for at least 30 years, no explanation has ever really been convincingly put forward. During analogue experiments on rifting volcanoes we have mixed the presence of a volcanic edifice with an underlying intrusive complex. The models use a rubber sheet that is extended and provides a broad area of extension (in contrast to many moving plate models that have one localised velocity discontinuity). This well suits the situation in many rifts and diffuse strike-slip zones (i.e. Central America and the East African Rift). We have noted the formation of localised extension bracketing the volcano, the location of which depends on the position of the analogue intrusion. Thus, we think we have found the answer to this long standing puzzle. We propose that diffuse extension of a volcano and intrusive complex generates two zones of faulting at the edge of the intrusion along the axis of greatest extensional strain. These serve to create surface faulting and preferential pathways for dykes. This positioning may also create craters aligned along the axis of extension, which is another notable feature of volcanoes in Central America. Paired volcanoes and volcanic uplifts in the Danakil region of Ethiopia may also be a consequence of such a process and lead us to draw some new preliminary cross sections of the Erta Ale volcanic range.

  14. Micro-and nanostructured silicon-based superomniphobic surfaces.

    PubMed

    Nguyen, Thi Phuong Nhung; Boukherroub, Rabah; Thomy, Vincent; Coffinier, Yannick

    2014-02-15

    We report on the fabrication of silicon nanostructured superhydrophobic and superoleophobic surfaces also called "superomniphobic" surfaces. For this purpose, silicon interfaces with different surface morphologies, single or double scale structuration, were investigated. These structured surfaces were chemically treated with perfluorodecyltrichlorosilane (PFTS), a low surface energy molecule. The morphology of the resulting surfaces was characterized using scanning electron microscopy (SEM). Their wetting properties: static contact angle (CA) and contact angle hysteresis (CAH) were investigated using liquids of various surface tensions. Despite that we found that all the different morphologies display a superhydrophobic character (CA>150° for water) and superoleophobic behavior (CA ? 140° for hexadecane), values of hysteresis are strongly dependent on the liquid surface tension and surface morphology. The best surface described in this study was composed of a dual scale texturation i.e. silicon micropillars covered by silicon nanowires. Indeed, this surface displayed high static contact angles and low hysteresis for all tested liquids. PMID:24370432

  15. A comparative experimental investigation of torque capabilities induced by conventional and active, passive self-ligating brackets.

    PubMed

    Katsikogianni, Eleni N; Reimann, Susanne; Weber, Anna; Karp, Jakob; Bourauel, Christoph

    2014-11-19

    Summary INTRODUCTION : A proper selected bracket-archwire combination displays a determining factor in the efficacy of torque applied to a tooth at the final stages of an orthodontic treatment. The objective of the current study was to assess the torque capabilities of various bracket systems combined with diverse archwire materials and cross-sections. PMID:25414477

  16. 26 CFR 1.63-1 - Change of treatment with respect to the zero bracket amount and itemized deductions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Change of treatment with respect to the zero bracket amount and itemized deductions. 1.63-1 Section...Income § 1.63-1 Change of treatment with respect to the zero bracket amount and itemized deductions. (a) In...

  17. 26 CFR 1.63-1 - Change of treatment with respect to the zero bracket amount and itemized deductions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Change of treatment with respect to the zero bracket amount and itemized deductions. 1.63-1 Section...Income § 1.63-1 Change of treatment with respect to the zero bracket amount and itemized deductions. (a) In...

  18. 26 CFR 1.63-1 - Change of treatment with respect to the zero bracket amount and itemized deductions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Change of treatment with respect to the zero bracket amount and itemized deductions. 1.63-1 Section...Income § 1.63-1 Change of treatment with respect to the zero bracket amount and itemized deductions. (a) In...

  19. 26 CFR 1.63-1 - Change of treatment with respect to the zero bracket amount and itemized deductions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Change of treatment with respect to the zero bracket amount and itemized deductions. 1.63-1 Section...Income § 1.63-1 Change of treatment with respect to the zero bracket amount and itemized deductions. (a) In...

  20. 26 CFR 1.63-1 - Change of treatment with respect to the zero bracket amount and itemized deductions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Change of treatment with respect to the zero bracket amount and itemized deductions. 1.63-1 Section...Income § 1.63-1 Change of treatment with respect to the zero bracket amount and itemized deductions. (a) In...

  1. Tooth surface and pulp chamber temperatures developed during electrothermal bonding.

    PubMed

    Mizrahi, E; Cleaton-Jones, P; Landy, C

    1996-05-01

    The rationale of electrothermal bonding is based on the premise that when an electric current is passed across the beaks of tweezers holding a stainless steel orthodontic bracket, heat will be generated by virtue of the electrical resistance of the steel bracket. This study was carried out to evaluate the temperatures generated on the tooth surface at the bracket/tooth interface and within the pulp chamber during electrothermal bonding. Temperatures were recorded with 5 and 7.5 A current levels applied as a 1 second pulse with time intervals between pulses of 1, 2, 3, and 4 seconds. The data showed that after three pulses with a 5 A current, the temperature on the tooth surface ranged between 43.3 degrees C (4 second intervals) to 53.6 degrees C (1 second intervals). By using a 7.5 A current, the temperature ranged from 77.5 degrees C (4 second intervals) to 85.9 degrees C (1 second intervals). The pulp chamber temperatures were evaluated in vitro for a mandibular incisor, the maxillary central and lateral incisors, a canine, a premolar, and a molar. The pulp chamber temperature of a mandibular incisor responded most, whereas that of premolars and molars responded least to temperature changes on the labial surface. The increase in mandibular incisor pulp chamber temperature after three pulses was 2.1 degrees C for 5 A and 2.8 degrees C for 7.5 A current while for a premolar the increase ranged from 0.9 degree C to 1.6 degrees C. On the basis of current evidence the increase in pulp chamber temperatures during electrothermal bonding may be considered to be clinically safe. PMID:8638595

  2. Surface plasmon resonance based fiber optic refractive index sensors

    NASA Astrophysics Data System (ADS)

    Hlubina, Petr; Kadulova, Miroslava; Ciprian, Dalibor

    2014-12-01

    Refractive index sensors based on surface plasmon resonance (SPR) in a thin metal film deposited on an unclad core of a multimode fiber are presented. The sensing element of the fiber optic SPR sensors is a bare core of a step-index optical fiber made of fused silica with a double-sided sputtered gold film. First, an in-line transmissionbased sensing scheme with the fiber optic SPR probe is used. Second, a reflection-based sensing scheme with a terminated fiber optic SPR probe is employed. The fiber optic SPR probes have different lengths and the thickness of the sputtered gold film is about 50 nm. Both sensing schemes utilize a wavelength interrogation method so that the refractive index of a liquid is sensed by measuring the position of the dip in the transmitted or reflected spectral intensity distribution. As an example, the aqueous solutions of ethanol with refractive indices in a range from 1.333 to 1.364 are measured. For the transmission-based sensing scheme a polarization-dependent response is revealed.

  3. Hippocampal shape analysis: surface-based representation and classification

    NASA Astrophysics Data System (ADS)

    Shen, Li; Ford, James; Makedon, Fillia; Saykin, Andrew

    2003-05-01

    Surface-based representation and classification techniques are studied for hippocampal shape analysis. The goal is twofold: (1) develop a new framework of salient feature extraction and accurate classification for 3D shape data; (2) detect hippocampal abnormalities in schizophrenia using this technique. A fine-scale spherical harmonic expansion is employed to describe a closed 3D surface object. The expansion can then easily be transformed to extract only shape information (i.e., excluding translation, rotation, and scaling) and create a shape descriptor comparable across different individuals. This representation captures shape features and is flexible enough to do shape modeling, identify statistical group differences, and generate similar synthetic shapes. Principal component analysis is used to extract a small number of independent features from high dimensional shape descriptors, and Fisher's linear discriminant is applied for pattern classification. This framework is shown to be able to perform well in distinguishing clear group differences as well as small and noisy group differences using simulated shape data. In addition, the application of this technique to real data indicates that group shape differences exist in hippocampi between healthy controls and schizophrenic patients.

  4. Sensing-Applications of Surface-Based Single Vesicle Arrays

    PubMed Central

    Christensen, Sune M.; Stamou, Dimitrios G.

    2010-01-01

    A single lipid vesicle can be regarded as an autonomous ultra-miniaturised 3D biomimetic “scaffold” (Ø ? 13 nm) ideally suited for reconstitution and interrogation of biochemical processes. The enclosing lipid bilayer membrane of a vesicle can be applied for studying binding (protein/lipid or receptor/ligand interactions) or transmembrane events (membrane permeability or ion channel activation) while the aqueous vesicle lumen can be used for confining few or single macromolecules and probe, e.g., protein folding, catalytic pathways of enzymes or more complex biochemical reactions, such as signal transduction cascades. Immobilisation (arraying) of single vesicles on a solid support is an extremely useful technique that allows detailed characterisation of vesicle preparations using surface sensitive techniques, in particular fluorescence microscopy. Surface-based single vesicle arrays allow a plethora of prototypic sensing applications in a high throughput format with high spatial and high temporal resolution. In this review we present a series of applications of single vesicle arrays for screening/sensing of: membrane curvature dependent protein-lipid interactions, bilayer tension, reactions triggered in the vesicle lumen, the activity of transmembrane protein channels and biological membrane fusion reactions. PMID:22163531

  5. Localized Surface Deformation Monitoring Applications using Ground Based Interferometric Radar

    NASA Astrophysics Data System (ADS)

    Legarsky, J. J.; Gomez, F. G.; Rosenblad, B.; Loehr, E.; Gurnani, G.; Fallert, Z.; Gilliam, J.

    2014-12-01

    Ground based interferometric radar (GBIR) measurements of localized surface deformation may be sought-after in various geosciences applications. The University of Missouri (MU) GBIR system is highly portable; moreover, it can be removed and re-positioned at the same point with geodetic-grade precision for long-term and repeat surveys. Initial quick-look imagery at C-band and Ku-band may be viewed in near real-time at the study site. Polarimetric calibration, radiometric calibration, and time-series analysis may further enhance the imagery. The MU GBIR has demonstrated millimeter and better sensitivity to localized surface deformation. Using real-aperture imaging and precision rotation, the MU GBIR acquires data by deploying three antennas that may be mounted parallel to one another on a 1-meter high tower. During typical operation, images are acquired by azimuthally rotating the GBIR antennas about its vertical axis. During deployment, the fast imaging capabilities allow a data collect scan in about 20 seconds for a 180 degree field of view. During the 2013 and 2014 field seasons using the MU GBIR, several locations were studied. The study sites include a rockfall experiment in Colorado, several dams in Kansas and Missouri, and a rock glacier in southern Colorado. Study results and additional progress will be presented. These projects are sponsored by grants from the University of Missouri Research Board and the National Science Foundation.

  6. Electrostatic painting of nonconductive surfaces with water-base paints

    Microsoft Academic Search

    I. I. Inculet; R. G. Klein

    1996-01-01

    Electrostatic corona painting on nonconductive surfaces normally requires a ground-connected conductive precoating of the surface in order to dissipate the continuously incoming ionic charge from the corona gun. If the surface charge does not flow to ground, the resulting surface electric field will repel a substantial amount of the incoming paint. The authors present a new painting method consisting of

  7. Torque Stability of Plastic Brackets Following Multiple Loading and Artificial Material Aging – an In-Vitro Comparison

    Microsoft Academic Search

    Matthias Möller; Arndt Klocke; Reza Sadat-Khonsari; Volker Schlegel; Bärbel Kahl-Nieke

    2009-01-01

    \\u000a Abstract\\u000a \\u000a \\u000a Objective:\\u000a   The objective of this study was to compare the loaddeflection\\u000a behavior of plastic brackets made of various materials in\\u000a response to repeated torque loads with each other and with steel\\u000a brackets. Material fatigue during wire’s play in the bracket slot, the\\u000a brackets’ elasticity and the torsional forces applied were analyzed.\\u000a \\u000a \\u000a \\u000a \\u000a Material and Methods:\\u000a   Groups of ten brackets, each

  8. Multilayer-graphene-based amplifier of surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Yurchenko, Stanislav O.; Komarov, Kirill A.; Pustovoit, Vladislav I.

    2015-05-01

    The amplification of surface acoustic waves (SAWs) by a multilayer graphene (MLG)-based amplifier is studied. The conductivity of massless carriers (electrons or holes) in graphene in an external drift electric field is calculated using Boltzmann's equation. At some carrier drift velocities, the real part of the variable conductivity becomes negative and MLG can be employed in SAW amplifiers. Amplification of Blustein's and Rayleigh's SAWs in CdS, a piezoelectric hexagonal crystal of the symmetry group C6v, is considered. The corresponding equations for SAW propagation in the device are derived and can be applied to other substrate crystals of the same symmetry. The results of the paper indicate that MLG can be considered as a perspective material for SAW amplification and related applications.

  9. Infrared transparent frequency selective surface based on metallic meshes

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Xu, Nianxi; Liu, Hai; Gao, Jinsong

    2014-02-01

    This paper presents an infrared transparent frequency selective surface (ITFSS) based on metallic meshes. In this ITFSS structure, periodic cross-slot units are integrated on square metallic meshes empowered by coating and UV-lithography. A matching condition is proposed to avoid the distortion of units. Experimental results show that this ITFSS possesses a good transmittance of 80% in the infrared band of 3-5 ?m, and also a stable band-pass behavior at the resonance frequency of 36.4 GHz with transmittance of -0.56 dB. Theoretical simulations about the ITFSS diffractive characteristics and frequency responses are also investigated. The novel ITFSS will attract renewed interest and be exploited for applications in various fields.

  10. Infrared transparent frequency selective surface based on metallic meshes

    SciTech Connect

    Yu, Miao [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China) [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Xu, Nianxi; Liu, Hai; Gao, Jinsong, E-mail: gaojs@ciomp.ac.cn [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)] [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)

    2014-02-15

    This paper presents an infrared transparent frequency selective surface (ITFSS) based on metallic meshes. In this ITFSS structure, periodic cross-slot units are integrated on square metallic meshes empowered by coating and UV-lithography. A matching condition is proposed to avoid the distortion of units. Experimental results show that this ITFSS possesses a good transmittance of 80% in the infrared band of 3–5 ?m, and also a stable band-pass behavior at the resonance frequency of 36.4 GHz with transmittance of ?0.56 dB. Theoretical simulations about the ITFSS diffractive characteristics and frequency responses are also investigated. The novel ITFSS will attract renewed interest and be exploited for applications in various fields.

  11. Quantifying modern biomes based on surface pollen data in China

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Ni, Jian; Herzschuh, Ulrike

    2010-12-01

    Large-scale surface pollen records and reconstructions of modern biomes are a necessary prerequisite for the understanding of past vegetation and climate changes, especially in large countries such as China which is subject to a variety of climatic regimes and has experienced long-term intensive anthropogenic disturbances. An updated surface pollen data set consisting of 2324 samples and 737 taxa is used to reconstruct biome distribution in China according to a newly established and well-tested global classification of plant functional types, based on the regional assessment of pollen taxa and the quantitative pollen-biome assignment method of biomization. Nineteen reconstructed types of biome present a reasonable reflection of the latitudinal and altitudinal distributions of modern vegetation in China. Incorrect assignment has previously occurred in some biomes, for example among the cold and cool temperate coniferous forests and mixed forest, among warm-temperate evergreen forest, mixed forest and tropical forests, and among temperate shrubland, grassland, desert and tundra biomes. Mega-biomes, grouped for the same bioclimatic zones, result in a better reconstruction than the nineteen separate biome types. The correct assignments increased from 68.8% to 80.6%. However, comparison of pollen-based biome reconstructions to climate-driven vegetation simulations performed using the global vegetation model BIOME4 indicates a low correlation rate (only 24.8%), suggesting that more needs to be done to combine palaeoenvironmental data with model simulations of past vegetation changes. The misassignment of surface pollen to modern biomes usually occurs in areas which have similar bioclimatic features and vegetation types and for biomes which share the same plant functional types. These mis-matches often occur in mountainous regions where transitional vegetation zones occur on hill slopes at mid-altitudes. Our new modern biome reconstruction for China is more robust and reliable; however continued analysis of pollen records is required in the remote areas of western China and the Tibetan Plateau, as well as in regions of central and eastern China which have suffered from high levels of anthropogenic activity. This type of anthropogenic biome reconstruction presents a new challenge.

  12. Rasetti-Regge Dirac bracket formulation of Lagrangian fluid dynamics of vortex filaments

    Microsoft Academic Search

    Darryl D. Holm

    2003-01-01

    We review the Rasetti-Regge Dirac bracket (RRDB) for determining the constrained Hamiltonian dynamics of vortex filaments moving with an incompressible potential flow of superfluid helium-II in the Lagrangian fluid picture. We compare the equations for Lagrangian vortex filaments with their corresponding Eulerian vorticity dynamics in the examples of the Euler fluid, superfluid vortices, the local induction approximation (LIA), the Rosenhead

  13. The moments of the hydrogen atom by the method of brackets

    E-print Network

    Ivan Gonzalez; Karen Kohl; Igor Kondrashuk; Victor H. Moll; Daniel Salinas

    2015-05-23

    Expected values of powers of the radial coordinate in arbitrary hydrogen states are given, in the quantum case, by an integral involving the associated Laguerre function. The method of brackets is used to evaluate the integral in closed-form and to produce an expression for this average value as a finite sum.

  14. Insect feeding on spores of a bracket fungus, Elfvingia applanata (Pers.) Karst. (Ganodermataceae, Aphyllophorales)

    Microsoft Academic Search

    Nobuko Tuno

    1999-01-01

    Insects visiting sporocarps of Elfvingia applanata, a wood-rotting bracket fungus, were examined in Kyoto, central Japan. Mycodrosophila flies (Drosophilidae: Diptera) were predominant and visited the spore-producing sporocarps exclusively. They were observed feeding on the spores, and a number of spores seemed to be alive even after having passed through insects’ digestive tracts. In addition, the insects attached a number of

  15. Symbolic algorithms for the computation of Moshinsky brackets and nuclear matrix elements

    Microsoft Academic Search

    D. Ursescu; M. Tomaselli; T. Kuehl; S. Fritzsche

    2005-01-01

    To facilitate the use of the extended nuclear shell model (NSM), a F ERMI module for calculating some of its basic quantities in the framework of MAPLE is provided. The Moshinsky brackets, the matrix elements for several central and non-central interactions between nuclear two-particle states as well as their expansion in terms of Talmi integrals are easily given within a

  16. A silicon-based electrical source of surface plasmon polaritons.

    PubMed

    Walters, R J; van Loon, R V A; Brunets, I; Schmitz, J; Polman, A

    2010-01-01

    After decades of process scaling driven by Moore's law, the silicon microelectronics world is now defined by length scales that are many times smaller than the dimensions of typical micro-optical components. This size mismatch poses an important challenge for those working to integrate photonics with complementary metal oxide semiconductor (CMOS) electronics technology. One promising solution is to fabricate optical systems at metal/dielectric interfaces, where electromagnetic modes called surface plasmon polaritons (SPPs) offer unique opportunities to confine and control light at length scales below 100 nm (refs 1, 2). Research groups working in the rapidly developing field of plasmonics have now demonstrated many passive components that suggest the potential of SPPs for applications in sensing and optical communication. Recently, active plasmonic devices based on III-V materials and organic materials have been reported. An electrical source of SPPs was recently demonstrated using organic semiconductors by Koller and colleagues. Here we show that a silicon-based electrical source for SPPs can be fabricated using established low-temperature microtechnology processes that are compatible with back-end CMOS technology. PMID:19966790

  17. Photoconductor surface modeling for defect compensation based on printed images

    NASA Astrophysics Data System (ADS)

    Eid, Ahmed H.; Cooper, Brian E.

    2015-01-01

    Manufacturing imperfections of photoconductor (PC) drums in electrophotographic (EP) printers cause low- frequency artifacts that could produce objectionable non-uniformities in the final printouts. In this paper, we propose a technique to detect and quantify PC artifacts. Furthermore, we spatially model the PC drum surface for dynamic compensation of drum artifacts. After scanning printed pages of flat field areas, we apply a wavelet- based filtering technique to the scanned images to isolate the PC-related artifacts from other printing artifacts, based on the frequency, range, and direction of the PC defects. Prior knowledge of the PC circumference determines the printed area at each revolution of the drum for separate analysis. Applied to the filtered images, the expectation maximization (EM) algorithm models the PC defects as a mixture of Gaussians. We use the estimated parameters of the Gaussians to measure the severity of the defect. In addition, a 2-D polynomial fitting approach characterizes the spatial artifacts of the drum, by analyzing multiple revolutions of printed output. The experimental results show a high correlation of the modeled artifacts from different revolutions of a drum. This allows for generating a defect-compensating profile of the defective drum.

  18. An integrated software suite for surface-based analyses of cerebral cortex

    NASA Technical Reports Server (NTRS)

    Van Essen, D. C.; Drury, H. A.; Dickson, J.; Harwell, J.; Hanlon, D.; Anderson, C. H.

    2001-01-01

    The authors describe and illustrate an integrated trio of software programs for carrying out surface-based analyses of cerebral cortex. The first component of this trio, SureFit (Surface Reconstruction by Filtering and Intensity Transformations), is used primarily for cortical segmentation, volume visualization, surface generation, and the mapping of functional neuroimaging data onto surfaces. The second component, Caret (Computerized Anatomical Reconstruction and Editing Tool Kit), provides a wide range of surface visualization and analysis options as well as capabilities for surface flattening, surface-based deformation, and other surface manipulations. The third component, SuMS (Surface Management System), is a database and associated user interface for surface-related data. It provides for efficient insertion, searching, and extraction of surface and volume data from the database.

  19. An Integrated Software Suite for Surface-based Analyses of Cerebral Cortex

    PubMed Central

    Van Essen, David C.; Drury, Heather A.; Dickson, James; Harwell, John; Hanlon, Donna; Anderson, Charles H.

    2001-01-01

    The authors describe and illustrate an integrated trio of software programs for carrying out surface-based analyses of cerebral cortex. The first component of this trio, SureFit (Surface Reconstruction by Filtering and Intensity Transformations), is used primarily for cortical segmentation, volume visualization, surface generation, and the mapping of functional neuroimaging data onto surfaces. The second component, Caret (Computerized Anatomical Reconstruction and Editing Tool Kit), provides a wide range of surface visualization and analysis options as well as capabilities for surface flattening, surface-based deformation, and other surface manipulations. The third component, SuMS (Surface Management System), is a database and associated user interface for surface-related data. It provides for efficient insertion, searching, and extraction of surface and volume data from the database. PMID:11522765

  20. A Surface Plasmon Enhanced Infrared Photodetector Based on InAs Quantum Dots

    E-print Network

    Krishna, Sanjay

    A Surface Plasmon Enhanced Infrared Photodetector Based on InAs Quantum Dots Chun-Chieh Chang to a level suitable for emerging surveillance and medical diagnostic applications. KEYWORDS Surface plasmon, there has been a great deal of interest in confining light strongly at the metal surface by surface plasmons

  1. REVIEW ARTICLE: Trends in interfacial design for surface plasmon resonance based immunoassays

    Microsoft Academic Search

    Dhesingh Ravi Shankaran; Norio Miura

    2007-01-01

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the

  2. A Global Merged LandAirSea Surface Temperature Reconstruction Based on Historical Observations (18801997)

    E-print Network

    A Global Merged Land­Air­Sea Surface Temperature Reconstruction Based on Historical Observations 2004) ABSTRACT A merged land­air­sea surface temperature reconstruction analysis is developed an analy- sis of the merged surface temperature is produced. The analysis uses a sea surface temperature

  3. Surface plasmon resonance based pesticide assay on a renewable biosensing surface using the reversible concanavalin A monosaccharide interaction

    Microsoft Academic Search

    Juraj Švitel; Anatoli Dzgoev; Kumaran Ramanathan; Bengt Danielsson

    2000-01-01

    A competitive immunoassay based on surface plasmon resonance (SPR) for the detection of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) is reported. The novelty of the assay is based on the regeneration of the chip surface by the reversible interaction between monosaccharide (d-glucose) and lectin (Concanavalin A). Concanavalin A-2,4-D conjugate was chemically synthesized, purified and used for binding to the SPR chip

  4. Reproducibility of UAV-based earth surface topography based on structure-from-motion algorithms.

    NASA Astrophysics Data System (ADS)

    Clapuyt, François; Vanacker, Veerle; Van Oost, Kristof

    2014-05-01

    A representation of the earth surface at very high spatial resolution is crucial to accurately map small geomorphic landforms with high precision. Very high resolution digital surface models (DSM) can then be used to quantify changes in earth surface topography over time, based on differencing of DSMs taken at various moments in time. However, it is compulsory to have both high accuracy for each topographic representation and consistency between measurements over time, as DSM differencing automatically leads to error propagation. This study investigates the reproducibility of reconstructions of earth surface topography based on structure-from-motion (SFM) algorithms. To this end, we equipped an eight-propeller drone with a standard reflex camera. This equipment can easily be deployed in the field, as it is a lightweight, low-cost system in comparison with classic aerial photo surveys and terrestrial or airborne LiDAR scanning. Four sets of aerial photographs were created for one test field. The sets of airphotos differ in focal length, and viewing angles, i.e. nadir view and ground-level view. In addition, the importance of the accuracy of ground control points for the construction of a georeferenced point cloud was assessed using two different GPS devices with horizontal accuracy at resp. the sub-meter and sub-decimeter level. Airphoto datasets were processed with SFM algorithm and the resulting point clouds were georeferenced. Then, the surface representations were compared with each other to assess the reproducibility of the earth surface topography. Finally, consistency between independent datasets is discussed.

  5. Normals estimation for digital surfaces based on convolutions

    E-print Network

    Paris-Sud XI, Université de

    the curve's length or its tangent vectors [12]. These methods have been extended to the 3D case with digital plane recognition to estimate the area of the surface of a 3D digital object [18]. Directional tangent-surface convolution (Section 3) which extends to digital surfaces the classical 2D filters used in image pro

  6. Effect of multiple debonding sequences on shear bond strength of new stainless steel brackets

    PubMed Central

    Eslamian, Ladan; Borzabadi-Farahani, Ali; Tavakol, Pegah; Tavakol, Ali; Amini, Nazila; Lynch, Edward

    2015-01-01

    Objectives: This in-vitro study aimed at evaluating the effect of three debonding sequences on the shear bond strength (SBS) of new stainless steel (SS) brackets. Materials and Methods: Stainless steel twin brackets (0.022-inch, American Orthodontics, Sheboygan, WI, USA) were bonded with light cure adhesive (Transbond XT, 3M Unitek, St. Paul, MN, USA) to 80 newly extracted human premolars after acid etching with 37% phosphoric acid (30 s). Brackets were debonded with a universal testing machine, and new brackets were bonded to teeth using the same adhesive and same manner. This process was repeated twice, and brackets were debonded within 24 h after bonding. The longitudinal changes of average SBS were assessed with the repeated measures ANOVA. Post-hoc tests using the Bonferroni correction were also used to compare the average SBS at three debonding sequences. Result: The mean SBS decreased significantly after each debonding sequence (P < 0.01). The corresponding mean values (standard deviation, 95% CI) after the first, second, and third debonding sequences were 22.88 MPa (4.08, 21.97-22.79), 19.36 MPa (4.54, 18.62-20.64), and 16.67 MPa (4.27, 15.72-17.62), respectively. There was no significant difference among the adhesive remnant index (ARI) scores of three debonding sequences (?2= 5.067, df = 6, P = 0.53). Conclusion: Average SBS after three debonding sequences was significantly decreased, but was above the recommended 5.9-7.8 MPa. In-vivo studies are required to validate the finding of this study. PMID:26020036

  7. Improved Constructions of Delaunay Based Contour Surfaces SiuWing Cheng \\Lambda Tamal K. Dey y

    E-print Network

    Dey, Tamal Krishna

    Improved Constructions of Delaunay Based Contour Surfaces Siu­Wing Cheng \\Lambda Tamal K. Dey y surface construction also finds use in terrain modeling from topographic elevation contours, and morphing

  8. Improving chemical aqueous based intervention methods for microorganism elimination from fresh produce surfaces

    E-print Network

    Puerta-Gomez, Alex Frank

    2006-04-12

    the effectiveness of the chemical aqueous based intervention methods applied. Wettable surfaces (water contact angle < 90°) allowed more bacteria to attach after the washing and H2O2 chemical treatments. Roughness and surface polarity are intrinsic characteristics...

  9. Terahertz wave filter based on frequency-selective surface structure

    NASA Astrophysics Data System (ADS)

    Sun, Chao; Li, Jiu-sheng

    2011-11-01

    Terahertz radiations, which refer to the frequencies from 100GHz to 10THz, lie in the frequency gap between the infrared and microwave, have received considerable attention during the past decades. Due to their special prosperties, THz radiations have been applied in many fields such as gases, semiconductors, explosives materials, and environment pollutants. The technique is based on recording the time dependence of the electric field of a short electromagnetic pulse transmitted through a sample. The ratio of the Fourier transforms of the data recorded with and without the sample yields the complex transmission coefficient of the sample in the frequency domain. The absorption coefficient and the refractive index of the material studied are directly related to the amplitude and phase respectively of the transmitted field. Terahertz wave filter, a frequency-selective surface structure, has been characterized by terahertz time-domain spectroscopy in the region from 0.1 to 3THz. We have compared THz-TDS measurement and calculation results of the mode-matching theory of the terahertz wave filter, and find that the two data sets agree very closely. The peak of the transmittance of about 90.5%occurs at 0.45THz for the first case and the peak of the transmittance of about 89.4% occurs at 0.79THz for the second case.

  10. Terahertz wave filter based on frequency-selective surface structure

    NASA Astrophysics Data System (ADS)

    Sun, Chao; Li, Jiu-sheng

    2012-03-01

    Terahertz radiations, which refer to the frequencies from 100GHz to 10THz, lie in the frequency gap between the infrared and microwave, have received considerable attention during the past decades. Due to their special prosperties, THz radiations have been applied in many fields such as gases, semiconductors, explosives materials, and environment pollutants. The technique is based on recording the time dependence of the electric field of a short electromagnetic pulse transmitted through a sample. The ratio of the Fourier transforms of the data recorded with and without the sample yields the complex transmission coefficient of the sample in the frequency domain. The absorption coefficient and the refractive index of the material studied are directly related to the amplitude and phase respectively of the transmitted field. Terahertz wave filter, a frequency-selective surface structure, has been characterized by terahertz time-domain spectroscopy in the region from 0.1 to 3THz. We have compared THz-TDS measurement and calculation results of the mode-matching theory of the terahertz wave filter, and find that the two data sets agree very closely. The peak of the transmittance of about 90.5%occurs at 0.45THz for the first case and the peak of the transmittance of about 89.4% occurs at 0.79THz for the second case.

  11. Graphene-based active slow surface plasmon polaritons.

    PubMed

    Lu, Hua; Zeng, Chao; Zhang, Qiming; Liu, Xueming; Hossain, Md Muntasir; Reineck, Philipp; Gu, Min

    2015-01-01

    Finding new ways to control and slow down the group velocity of light in media remains a major challenge in the field of optics. For the design of plasmonic slow light structures, graphene represents an attractive alternative to metals due to its strong field confinement, comparably low ohmic loss and versatile tunability. Here we propose a novel nanostructure consisting of a monolayer graphene on a silicon based graded grating structure. An external gate voltage is applied to graphene and silicon, which are separated by a spacer layer of silica. Theoretical and numerical results demonstrate that the structure exhibits an ultra-high slowdown factor above 450 for the propagation of surface plasmon polaritons (SPPs) excited in graphene, which also enables the spatially resolved trapping of light. Slowdown and trapping occur in the mid-infrared wavelength region within a bandwidth of ~2.1 ?m and on a length scale less than 1/6 of the operating wavelength. The slowdown factor can be precisely tuned simply by adjusting the external gate voltage, offering a dynamic pathway for the release of trapped SPPs at room temperature. The presented results will enable the development of highly tunable optoelectronic devices such as plasmonic switches and buffers. PMID:25676462

  12. Graphene-based active slow surface plasmon polaritons

    NASA Astrophysics Data System (ADS)

    Lu, Hua; Zeng, Chao; Zhang, Qiming; Liu, Xueming; Hossain, Md Muntasir; Reineck, Philipp; Gu, Min

    2015-02-01

    Finding new ways to control and slow down the group velocity of light in media remains a major challenge in the field of optics. For the design of plasmonic slow light structures, graphene represents an attractive alternative to metals due to its strong field confinement, comparably low ohmic loss and versatile tunability. Here we propose a novel nanostructure consisting of a monolayer graphene on a silicon based graded grating structure. An external gate voltage is applied to graphene and silicon, which are separated by a spacer layer of silica. Theoretical and numerical results demonstrate that the structure exhibits an ultra-high slowdown factor above 450 for the propagation of surface plasmon polaritons (SPPs) excited in graphene, which also enables the spatially resolved trapping of light. Slowdown and trapping occur in the mid-infrared wavelength region within a bandwidth of ~2.1 ?m and on a length scale less than 1/6 of the operating wavelength. The slowdown factor can be precisely tuned simply by adjusting the external gate voltage, offering a dynamic pathway for the release of trapped SPPs at room temperature. The presented results will enable the development of highly tunable optoelectronic devices such as plasmonic switches and buffers.

  13. Two simple designs for surface-plasmon-resonance-based sensing

    NASA Astrophysics Data System (ADS)

    Kobe, Andrea; Mozina, Janez I.

    1999-12-01

    Surface plasmon resonance spectroscopy is becoming an increasingly important technique in biotechnology and chemical sensing. We present two simple, low cost, high sensitivity devices. The first is laser based mechanical implementation of a Kretschmann setup. Angle sweep is realized in two stages: step motor is used for coarse angle setting, and continuous angle sweep is achieved with a mirror on a floppy disk drive and a cylindrical lens setup. A single detector with AD converter defines resolution of the device through its sampling speed and dynamic range, so high sensitivity can be achieved. Sensor probes are metal- coated microscope slides and sample volume is temperature controlled. Second devices is a disposable cuvette for use in a VIS spectrometer. Specially designed monolithic polycarbonate block provides the required optical path and appropriate incidence angle on a thin metal film, deposited on the block. No equipment is necessary and the cuvette can be used within special cell, such as temperature controlled vessel. Device is also discussed in view of a low cost fiberoptic implementation. Some experimental results are presented to prove the applicability of devices. Disadvantages of technical solutions, used in devices, are also taken into consideration.

  14. Graphene-based active slow surface plasmon polaritons

    PubMed Central

    Lu, Hua; Zeng, Chao; Zhang, Qiming; Liu, Xueming; Hossain, Md Muntasir; Reineck, Philipp; Gu, Min

    2015-01-01

    Finding new ways to control and slow down the group velocity of light in media remains a major challenge in the field of optics. For the design of plasmonic slow light structures, graphene represents an attractive alternative to metals due to its strong field confinement, comparably low ohmic loss and versatile tunability. Here we propose a novel nanostructure consisting of a monolayer graphene on a silicon based graded grating structure. An external gate voltage is applied to graphene and silicon, which are separated by a spacer layer of silica. Theoretical and numerical results demonstrate that the structure exhibits an ultra-high slowdown factor above 450 for the propagation of surface plasmon polaritons (SPPs) excited in graphene, which also enables the spatially resolved trapping of light. Slowdown and trapping occur in the mid-infrared wavelength region within a bandwidth of ~2.1??m and on a length scale less than 1/6 of the operating wavelength. The slowdown factor can be precisely tuned simply by adjusting the external gate voltage, offering a dynamic pathway for the release of trapped SPPs at room temperature. The presented results will enable the development of highly tunable optoelectronic devices such as plasmonic switches and buffers. PMID:25676462

  15. An ``optical diode'' based on surface plasmon cavity modes

    NASA Astrophysics Data System (ADS)

    Burns, Michael J.; Ye, Fan; Naughton, Michael J.

    2014-03-01

    We present the discovery and systematic study of a novel optical phenomenon that works like an ``optical diode,'' where the center of an optically thick circular Ag disk surrounded by step gap looks dark when observing in the far field from the top side, and appears bright when seeing from the bottom side. In both cases, the circular step gap circumference appears bright. We call the effect when observing from the top side the ``plasmonic halo,'' and the effect from the bottom side the ``reverse halo.'' In our previous work, we have demonstrated the physical nature of the ``plasmonic halo'' effect: modulation of transmission by the surface plasmon polariton (SPP) drumhead modes.[2] Here we will explain the ``reverse halo'' effect by a three-step process: coupling from photons to SPPs, interference of SPPs forming cavity modes, and out coupling from SPPs to photons. Full-wave electromagnetic simulations based on finite element method support our theory. We have thus arrived at a thorough understanding of this ``optical diode'' effect, which could have potential applications in biomedical plasmonics, dielectric constant sensing, discrete optical filtering, and photonic logic, among others. This work is supported by the W. M. Keck Foundation.

  16. Ground Based Interferometric Radar for Surface Monitoring Applications

    NASA Astrophysics Data System (ADS)

    Legarsky, J. J.; Gomez, F. G.; Rosenblad, B.; Loehr, E.; Gilliam, J.; Panigrahi, D.; Held, B.; Gurnani, G.

    2013-12-01

    Ground based interferometric radar (GBIR) measurements may be desirable for a number of surface deformation monitoring applications in the earth sciences. The University of Missouri (MU) GBIR system is highly portable, which helps facilitate rapid deployment to sites of interest. The MU GBIR has demonstrated millimeter and better sensitivity to deformation. In addition, the MU GBIR can be removed and re-positioned at the same point with geodetic-grade precision for repeat and long-term surveys. The MU GBIR's high portability and fast imaging capabilities allow rapid surveying scans about every 20 seconds when deployed. Near real time C-band and Ku-band imagery may be formed on site for initial quick looks. Imagery data may be further enhanced by polarimetric calibration, radiometric calibration, and time-series analysis. Over the 2012 and 2013 field seasons, the MU GBIR has collected measurements from multiple locations such as a glacier in Greenland, a canyon in Colorado, and several dams in Kansas and Missouri. Study results and additional progress will be presented. These projects are sponsored by grants from the University of Missouri Research Board and the National Science Foundation.

  17. A Surface-Based Fractal Information Dimension Method for Cortical Complexity Analysis

    Microsoft Academic Search

    Yuanchao Zhang; Jiefeng Jiang; Lei Lin; Feng Shi; Yuan Zhou; Chunshui Yu; Kuncheng Li; Tianzi Jiang

    2008-01-01

    In this paper, we proposed a new surface-based fractal information dimension (FID) method to quantify the cortical complexity.\\u000a Unlike the traditional box-counting method to measure the capacity dimension, our method is a surface-based fractal information\\u000a dimension method, which incorporates surface area into the probability calculation and thus encapsulates more information\\u000a of the original cortical surfaces. The accuracy of the algorithm

  18. Multifractal characterization of water soluble copper phthalocyanine based films surfaces

    NASA Astrophysics Data System (ADS)

    ??lu, ?tefan; Stach, Sebastian; Mahajan, Aman; Pathak, Dinesh; Wagner, Tomas; Kumar, Anshul; Bedi, R. K.; ??lu, Mihai

    2014-07-01

    This paper presents a multifractal approach to characterize the structural complexity of 3D surface roughness of CuTsPc films on the glass and quartz substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films prepared by drop cast method were investigated. CuTsPc films surface roughness was studied by AFM in tapping-mode™, in an aqueous environment, on square areas of 100 ?m2 and 2500 ?m2. A detailed methodology for CuTsPc films surface multifractal characterization, which may be applied for AFM data, was also presented. Analysis of surface roughness revealed that CuTsPc films have a multifractal geometry at various magnifications. The generalized dimension D q and the singularity spectrum f( ?) provided quantitative values that characterize the local scale properties of CuTsPc films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

  19. An efficient physically based parameterization to derive surface solar irradiance based on satellite atmospheric products

    NASA Astrophysics Data System (ADS)

    Qin, Jun; Tang, Wenjun; Yang, Kun; Lu, Ning; Niu, Xiaolei; Liang, Shunlin

    2015-05-01

    Surface solar irradiance (SSI) is required in a wide range of scientific researches and practical applications. Many parameterization schemes are developed to estimate it using routinely measured meteorological variables, since SSI is directly measured at a very limited number of stations. Even so, meteorological stations are still sparse, especially in remote areas. Remote sensing can be used to map spatiotemporally continuous SSI. Considering the huge amount of satellite data, coarse-resolution SSI has been estimated for reducing the computational burden when the estimation is based on a complex radiative transfer model. On the other hand, many empirical relationships are used to enhance the retrieval efficiency, but the accuracy cannot be guaranteed out of regions where they are locally calibrated. In this study, an efficient physically based parameterization is proposed to balance computational efficiency and retrieval accuracy for SSI estimation. In this parameterization, the transmittances for gases, aerosols, and clouds are all handled in full band form and the multiple reflections between the atmosphere and surface are explicitly taken into account. The newly proposed parameterization is applied to estimate SSI with both Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric and land products as inputs. These retrievals are validated against in situ measurements at the Surface Radiation Budget Network and at the North China Plain on an instantaneous basis, and moreover, they are validated and compared with Global Energy and Water Exchanges-Surface Radiation Budget and International Satellite Cloud Climatology Project-flux data SSI estimates at radiation stations of China Meteorological Administration on a daily mean basis. The estimation results indicates that the newly proposed SSI estimation scheme can effectively retrieve SSI based on MODIS products with mean root-mean-square errors of about 100 Wm- 1 and 35 Wm- 1 on an instantaneous and daily mean basis, respectively.

  20. Anterior Sectional Twin Bracket Appliance – Innovative Use for Correction of Single Tooth Crossbite: A Case Report with Biomechanics

    PubMed Central

    Raghav, Pradeep; Reddy, Munish C; Kanwal, Ritika

    2015-01-01

    ABSTRACT Anterior sectional twin bracket appliance (ASTBA) is a sectional mechanism that involves two brackets on upper central incisors. This appliance is previously been used for correction of rotated incisors and midline spacing. But, detail biomechanics for single tooth crossbite correction is not previously explained. Here, in this article, we are presenting a detailed biomechanics of ASTBA for anterior single tooth crossbite correction along with case report. How to cite this article: Verma RK, Raghav P, Reddy MC, Kanwal R. Anterior Sectional Twin Bracket Appliance– Innovative Use for Correction of Single Tooth Crossbite: A Case Report with Biomechanics. Int J Clin Pediatr Dent 2015;8(1): 66-69.

  1. Nanopatterned surfaces based on template-assisted multilayer electrodeposition.

    PubMed

    Kim, Minsoo; Kim, Jooncheol; Allen, Mark

    2015-04-01

    Selective, template-assisted growth of electrodeposited, layered materials leads to the top-down designable realization of nanopatterned surfaces with a large surface area (>1 cm(2) ) comprised of multi-dimensional, multiscale (10 nm-1 ?m) features, without the need of standard nanolithography. This process opens a manufacturable route to functional nanodevices that rely on anisotropic, nanoscale surface structures with controlled dimensions. PMID:25504916

  2. Automatic vertebral identification using surface-based registration

    NASA Astrophysics Data System (ADS)

    Herring, Jeannette L.; Dawant, Benoit M.

    2000-06-01

    This work introduces an enhancement to currently existing methods of intra-operative vertebral registration by allowing the portion of the spinal column surface that correctly matches a set of physical vertebral points to be automatically selected from several possible choices. Automatic selection is made possible by the shape variations that exist among lumbar vertebrae. In our experiments, we register vertebral points representing physical space to spinal column surfaces extracted from computed tomography images. The vertebral points are taken from the posterior elements of a single vertebra to represent the region of surgical interest. The surface is extracted using an improved version of the fully automatic marching cubes algorithm, which results in a triangulated surface that contains multiple vertebrae. We find the correct portion of the surface by registering the set of physical points to multiple surface areas, including all vertebral surfaces that potentially match the physical point set. We then compute the standard deviation of the surface error for the set of points registered to each vertebral surface that is a possible match, and the registration that corresponds to the lowest standard deviation designates the correct match. We have performed our current experiments on two plastic spine phantoms and one patient.

  3. Surface-recombination-free InGaAs/InP HBTs and the base contact recombination

    NASA Astrophysics Data System (ADS)

    Jin, Z.; Liu, X.; Prost, W.; Tegude, F.-J.

    2008-07-01

    Surface-recombination-free InGaAs/InP HBTs with graded base have been demonstrated. The HBTs were passivated by ammonium sulfide. The current gain of the nonself-aligned HBTs was independent of the emitter periphery, indicating that the surface recombination was removed by the passivation. For the self-aligned HBTs, the current gain was still dependent on the emitter periphery after the passivation due to the base contact recombination. A surface leakage channel has been identified to result in a significant increase in the base contact recombination. The passivation has two effects: one is the surface recombination velocity reduction and the other is the surface leakage channel elimination.

  4. Surface Modifications of Graphene-based Polymer Nanocomposites by Different Synthesis Techniques

    E-print Network

    Yanikoglu, Berrin

    as filler in conducting polypyrrole matrix in order to fabricate polymer-based nanocomposites. The effectSurface Modifications of Graphene-based Polymer Nanocomposites by Different Synthesis Techniques, polymerization #12;Surface Modifications of Graphene-based Polymer Nanocomposites by Different Synthesis

  5. FEATURE ARTICLE Unified Molecular Picture of the Surfaces of Aqueous Acid, Base, and Salt Solutions

    E-print Network

    FEATURE ARTICLE Unified Molecular Picture of the Surfaces of Aqueous Acid, Base, and Salt Solutions inorganic ions. Molecular dynamics calculations show that in salt solutions and bases the positively charged, consequently, these acids (unlike bases and salts) reduce the surface tension of water. The results

  6. Pipeline for the Creation of Surface-based Averaged Brain Atlases

    E-print Network

    Andrzejak, Artur

    Pipeline for the Creation of Surface-based Averaged Brain Atlases Anja Kuß Hans-Christian Hege for the creation of extendable surface-based anatomical insect brain atlases from 3D image data of a population. Understanding such neural functions is based on knowledge about the wiring of the brain and functional

  7. Facile creation of bio-inspired superhydrophobic Ce-based metallic glass surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Kesong; Li, Zhou; Wang, Weihua; Jiang, Lei

    2011-12-01

    A bio-inspired synthesis strategy was conducted to fabricate superhydrophobic Ce-based bulk metallic glass (BMG) surfaces with self-cleaning properties. Micro-nanoscale hierarchical structures were first constructed on BMG surfaces and then modified with the low surface energy coating. Surface structures, surface chemical compositions, and wettability were characterized by combining scanning electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, and contact angle measurements. Research indicated that both surface multiscale structures and the low surface free energy coating result in the final formation of superhydrophobicity.

  8. Facile creation of bio-inspired superhydrophobic Ce-based metallic glass surfaces

    SciTech Connect

    Liu Kesong; Li Zhou [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Wang Weihua [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Jiang Lei [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-12-26

    A bio-inspired synthesis strategy was conducted to fabricate superhydrophobic Ce-based bulk metallic glass (BMG) surfaces with self-cleaning properties. Micro-nanoscale hierarchical structures were first constructed on BMG surfaces and then modified with the low surface energy coating. Surface structures, surface chemical compositions, and wettability were characterized by combining scanning electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, and contact angle measurements. Research indicated that both surface multiscale structures and the low surface free energy coating result in the final formation of superhydrophobicity.

  9. Acid base properties of cyanobacterial surfaces I: Influences of growth phase and nitrogen metabolism on cell surface reactivity

    NASA Astrophysics Data System (ADS)

    Lalonde, S. V.; Smith, D. S.; Owttrim, G. W.; Konhauser, K. O.

    2008-03-01

    Significant efforts have been made to elucidate the chemical properties of bacterial surfaces for the purposes of refining surface complexation models that can account for their metal sorptive behavior under diverse conditions. However, the influence of culturing conditions on surface chemical parameters that are modeled from the potentiometric titration of bacterial surfaces has received little regard. While culture age and metabolic pathway have been considered as factors potentially influencing cell surface reactivity, statistical treatments have been incomplete and variability has remained unconfirmed. In this study, we employ potentiometric titrations to evaluate variations in bacterial surface ligand distributions using live cells of the sheathless cyanobacterium Anabaena sp. strain PCC 7120, grown under a variety of batch culture conditions. We evaluate the ability for a single set of modeled parameters, describing acid-base surface properties averaged over all culture conditions tested, to accurately account for the ligand distributions modeled for each individual culture condition. In addition to considering growth phase, we assess the role of the various assimilatory nitrogen metabolisms available to this organism as potential determinants of surface reactivity. We observe statistically significant variability in site distribution between the majority of conditions assessed. By employing post hoc Tukey-Kramer analysis for all possible pair-wise condition comparisons, we conclude that the average parameters are inadequate for the accurate chemical description of this cyanobacterial surface. It was determined that for this Gram-negative bacterium in batch culture, ligand distributions were influenced to a greater extent by nitrogen assimilation pathway than by growth phase.

  10. Surface Reactions Studied by Synchrotron Based Photoelectron Spectroscopy

    SciTech Connect

    Hrbek, J.

    1998-11-03

    The goal of this article is to illustrate the use of synchrotron radiation for investigating surface chemical reactions by photoelectron spectroscopy. A brief introduction and background information is followed by examples of layer resolved spectroscopy, oxidation and sulfidation of metallic, semiconducting and oxide surfaces.

  11. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

    2014-06-01

    A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

  12. Model-based deformable surface finding for medical images

    Microsoft Academic Search

    L. H. Staib; J. S. Duncan

    1996-01-01

    Describes a new global shape parameterization for smoothly deformable three-dimensional (3-D) objects, such as those found in biomedical images, whose diversity and irregularity make them difficult to represent in terms of fixed features or parts. This representation is used for geometric surface matching to 3-D medical image data, such as from magnetic resonance imaging (MRI). The parameterization decomposes the surface

  13. Surface-based bedload transport relation for gravel rivers

    Microsoft Academic Search

    G. Parker

    1990-01-01

    Bedload transport in gravel-bed rivers is accomplished by means of the mobilization of grains exposed on the bed surface. This mobilization is due to the action of fluid forces on the exposed grains. Substrate particles can participate in the bedload only to the extent that local or global scour results in their exposure on the surface. It follows that a

  14. Approximation-Based Similarity Search for 3-D Surface Segments

    Microsoft Academic Search

    Hans-Peter Kriegel; Thomas Seidl

    1998-01-01

    The issue of finding similar 3-D surface segments arises in many recent applications of spatial database systems, such as molecular biology, medical imaging, CAD, and geographic information systems. Surface segments being similar in shape to a given query segment are to be retrieved from the database. The two main questions are how to define shape similarity and how to efficiently

  15. Trochlear surface reconstruction and evaluation based on laser scanner acquisition

    Microsoft Academic Search

    R. Synave; C. Couture-Veschambre

    2010-01-01

    The purpose of this study is to investigate the accuracy, reproducibility and validation of linear measurements on digital reconstruction of the trochlear articular surface. Surface reconstruction is produced by a laser scanner acquisition pipeline that preserves rough data. Arc and chord measurements between chosen landmarks on physical specimens are simulated by geodesic path length evaluation on the corresponding digital models.

  16. Quantifying modern biomes based on surface pollen data in China

    Microsoft Academic Search

    Yu Chen; Jian Ni; Ulrike Herzschuh

    2010-01-01

    Large-scale surface pollen records and reconstructions of modern biomes are a necessary prerequisite for the understanding of past vegetation and climate changes, especially in large countries such as China which is subject to a variety of climatic regimes and has experienced long-term intensive anthropogenic disturbances. An updated surface pollen data set consisting of 2324 samples and 737 taxa is used

  17. A haptic-rendering technique based on hybrid surface representation

    Microsoft Academic Search

    Laehyun Kim; Gaurav S. Sukhatme; Mathieu Desbrun

    2004-01-01

    A novel haptic rendering technique using a hybrid surface representation addresses conventional limitations in haptic displays. A haptic interface lets the user touch, explore, paint, and manipulate virtual 3D models in a natural way using a haptic display device. A haptic rendering algorithm must generate a force field to simulate the presence of these virtual objects and their surface properties

  18. Flow condensation on copper-based nanotextured superhydrophobic surfaces.

    PubMed

    Torresin, Daniele; Tiwari, Manish K; Del Col, Davide; Poulikakos, Dimos

    2013-01-15

    Superhydrophobic surfaces have shown excellent ability to promote dropwise condensation with high droplet mobility, leading to enhanced surface thermal transport. To date, however, it is unclear how superhydrophobic surfaces would perform under the stringent flow condensation conditions of saturated vapor at high temperature, which can affect superhydrophobicity. Here, we investigate this issue employing "all-copper" superhydrophobic surfaces with controlled nanostructuring for minimal thermal resistance. Flow condensation tests performed with saturated vapor at a high temperature (110 °C) showed the condensing drops penetrate the surface texture (i.e., attain the Wenzel state with lower droplet mobility). At the same time, the vapor shear helped ameliorate the mobility and enhanced the thermal transport. At the high end of the examined vapor velocity range, a heat flux of ~600 kW m(-2) was measured at 10 K subcooling and 18 m s(-1) vapor velocity. This clearly highlights the excellent potential of a nanostructured superhydrophobic surface in flow condensation applications. The surfaces sustained dropwise condensation and vapor shear for five days, following which mechanical degradation caused a transition to filmwise condensation. Overall, our results underscore the need to investigate superhydrophobic surfaces under stringent and realistic flow condensation conditions before drawing conclusions regarding their performance in practically relevant condensation applications. PMID:23249322

  19. Acid base properties of cyanobacterial surfaces. II: Silica as a chemical stressor influencing cell surface reactivity

    NASA Astrophysics Data System (ADS)

    Lalonde, S. V.; Smith, D. S.; Owttrim, G. W.; Konhauser, K. O.

    2008-03-01

    Bacteria grow in complex solutions where the adsorption of aqueous species and nucleation of mineral phases on the cell surface may interfere with membrane-dependent homeostatic functions. While previous investigations have provided evidence that bacteria may alter their surface chemical properties in response to environmental stimuli, to our knowledge no effort has been made to evaluate surface compositional changes resulting from non-nutritional chemical stresses within a quantitative framework applicable to surface complexation modeling. We consider here the influence of exposure to silica on cyanobacterial surface chemistry, particularly in light of the propensity for cyanobacteria to become silicified in geothermal environments. Using data modeled from over 50 potentiometric titrations of the unsheathed cyanobacterium Anabaena sp. strain PCC 7120, we find that both abiotic geochemical and biotic biochemical-assimilatory factors have important and different effects on cell surface chemistry. Changes in functional group distribution that resulted from growth by different nitrogen assimilation pathways were greatest in the absence of dissolved silica and less important in its presence. Furthermore, out of the three nitrogen assimilation pathways investigated, in terms of surface functional group distribution, nitrate-reducing cultures were least sensitive, and ammonium-assimilating cultures were most sensitive, to changes in media silica concentration. When functional group distributions were plotted as a function of silica concentration, it appears that, with higher silica concentrations, basic groups (p Ka > 7) increase in concentration relative to acidic groups (p Ka < 7), and the total ligand densities (on a per-weight basis) decreased. The results imply a decrease in both the magnitude and density of surface charge as the net result of growth at high silica concentrations. Thus, Anabaena sp. appears to actively respond to growth in silicifying solutions by altering its surface properties in a manner that is likely to be manifested in nature by facilitated surface attachment. We conclude that potentiometric titrations reveal a Gram-negative bacterial surface whose properties are dynamic with respect to both nutrient and geochemical stressors.

  20. Surfaces

    E-print Network

    DeMaio, Ernest Vincent, 1964-

    1989-01-01

    Surfaces is a collection of four individual essays which focus on the characteristics and tactile qualities of surfaces within a variety of perceived landscapes. Each essay concentrates on a unique surface theme and purpose; ...

  1. Surface acid-base characteristics of fiber materials by contact angle measurements

    SciTech Connect

    Mao Youan (National Univ., of Defense and Technology, Changsha (China). Dept. of Materials Science and Applied Chemistry)

    1993-11-05

    Contact angle measurements were used to study the surface acid-base characteristics of treated and untreated carbon fibers, and of treated and untreated silicon carbide fibers. It has been shown that, when untreated the surfaces of these two fibers exhibits amphoteric, but the base character is dominant. After oxidization in a liquid phase, the surface acid character of the carbon fibers changes little, whereas the base character becomes much stronger. The treatment, with boiling-concentrated HNO[sub 3] for three hours and the sintering treatment in air at 500 C. for eight hours, has little effect on the surface acid-base characteristics of the silicon carbide fibers.

  2. Ultranarrow band absorbers based on surface lattice resonances in nanostructured metal surfaces.

    PubMed

    Li, Zhongyang; Butun, Serkan; Aydin, Koray

    2014-08-26

    Nanostructured metals have received a significant amount of attention in recent years due to their exciting plasmonic and photonic properties enabling strong field localization, light concentration, and strong absorption and scattering at their resonance frequencies. Resonant plasmonic and metamaterial absorbers are of particular interest for applications in a wide variety of technologies including photothermal therapy, thermophotovoltaics, heat-assisted magnetic recording, hot-electron collection, and biosensing. However, it is rather challenging to realize ultranarrow absorption bands using plasmonic materials due to large optical losses in metals that decrease the quality factor of optical resonators. Here, we theoretically and experimentally demonstrate an ultranarrow band absorber based on the surface lattice resonances (SLRs) in periodic nanowire and nanoring arrays on optically thick, reflecting metallic films. In experiments, we observed ultranarrow band resonant absorption peaks with a bandwidth of 12 nm and absorption amplitude exceeding 90% at visible frequencies. We demonstrate that the resonance absorption wavelength, amplitude of the absorption peak, and the bandwidth can be controlled by tuning the periodicity and the thickness of nanoring and nanowire arrays. Unlike conventional plasmonic absorbers utilizing common metal–insulator–metal stacks, our narrow band absorber consists solely of metals, facilitating stronger optical interaction between the SLR of periodic nanostructures and the highly reflective film. Moreover, by introducing asymmetry to the nanoring/nanowire hybrid system, we observe the spectral evolution of resonance splitting enabled by strong coupling between two individual SLRs arising from nanoring and nanowire arrays. Designing such all-metallic nanostructure arrays is a promising route for achieving ultranarrow band absorbers which can be used as absorption filters, narrow band thermal emitters in thermophotovoltaics, and plasmonic biosensors. PMID:25072803

  3. One way of surface alloying treatment on iron surface based on surface mechanical attrition treatment and heat treatment

    NASA Astrophysics Data System (ADS)

    Du, Huayun; Wei, Yinghui; Lin, Wanming; Hou, Lifeng; Liu, Zengqing; An, Yanli; Yang, Wenfu

    2009-07-01

    A method of surface alloying treatment has been developed: Ni powders were welded into the surface of iron plates by Surface Mechanical Attrition Treatment (SMAT), followed by annealing at certain temperature for 30 min. A Ni-Fe alloy layer with thickness about 100 ?m in the sample surface was fabricated on pure iron plate. Scanning electron microscope (SEM), glow discharge spectrum (GDS), and X-ray diffraction (XRD) methods were used to analyze the microstructure, the composition and the phases of the alloy layer. Studies on the interface microstructure indicated that there was significant atomic diffusion and formation of multilayer of intermetallic compound and solid solution in SMAT process. Subsequent annealing accelerates the alloying process. The corrosion test shows the sample by SMAT treated with Ni powders exhibit the best corrosion resistance.

  4. Moire based optical surface profiler for the minting industry

    NASA Astrophysics Data System (ADS)

    Oreb, Bozenko F.; Larkin, Kieran G.; Fairman, Philip S.; Ghaffari, M.

    1992-12-01

    An Optical Surface Profiler (OSP130) has been developed for the metrology of master tooling used in the coin stamping process. The OSP130 measure, in a non-contacting manner, the surface relief of tools ranging in diameter from 10 mm to 300 mm. Rapid measurements are performed simultaneously on a large grid of equispaced points across the surface of the tool. From the relief data, many parameters such as the location of high and low features, volume of impression, background curvatures and various diameters can be quickly evaluated. The technique used is phase-shifting moire profilometry. A white light projector illuminates a periodic transmission grating which is then imaged onto the object surface. The light pattern on the object is viewed by a high resolution TV camera connected to a computer. The grating is shifted under computer control to a number of positions and corresponding intensity images of the deformed pattern on the object surface are stored in the computer. From the intensity images a phase map, representing the deformation of the periodic grating by the surface relief, is evaluated and compared with an undeformed pattern. This results in an accurate contour map of the surface relief with an uncertainty less than 1% of the relief excursion on the object. Details of the instrument and its use at the Royal Australian Mint are presented.

  5. Surface-Dried Viruses Can Resist Glucoprotamin-Based Disinfection

    PubMed Central

    Rapp, Ingrid

    2014-01-01

    Touching of contaminated objects and surfaces is a well-known method of virus transmission. Once they are attached to the hands, viruses can easily get adsorbed and initiate infection. Hence, disinfection of frequently touched surfaces is of major importance to prevent virus spreading. Here we studied the antiviral activity of a glucoprotamin-containing disinfectant against influenza A virus and the model virus vaccinia virus (VACV) dried on inanimate surfaces. The efficacy of the surface disinfectant on stainless steel, polyvinyl chloride, and glass coupons was investigated in a quantitative carrier test. Vacuum-dried viruses were exposed to 0.25%, 0.5%, and 1% disinfectant for 5 min, 15 min, and 30 min without agitation, and residual infectivity was determined by endpoint titration. Although glucoprotamin was highly active against both viruses in suspension, limited antiviral activity against the surface-dried viruses was detected. Even after 30 min of exposure to 1% disinfectant, VACV was not completely inactivated. Furthermore, influenza A virus inactivation was strongly affected by the surface composition during the 5-min and 15-min treatments with 0.25% and 0.5% disinfectant. The results presented in this study highlight the relevance of practical tests to assess the antiviral activity of surface disinfectants. High virucidal activity in solution is not necessarily indicative of high antiviral activity against surface-dried viruses. In addition, we want to emphasize that the mere exposure of surfaces to disinfectants might not be sufficient for virus inactivation and mechanical action should be applied to bring attached viruses into contact with virucidal compounds. PMID:25217017

  6. Higher-order syzygies for the bracket algebra and for the ring of coordinates of the Grassmanian.

    PubMed Central

    Anick, D; Rota, G C

    1991-01-01

    A Poincaré resolution is given for the supersymmetric ring of brackets over a signed alphabet. As a consequence, a resolution is found for the ring of coordinates of the Grassmanian variety in projective space over any infinite field. PMID:11607210

  7. RTM-based Teleseismic Reflection Tomography with Free Surface Multiples

    NASA Astrophysics Data System (ADS)

    Burdick, S. A.; De Hoop, M. V.; van der Hilst, R. D.

    2013-12-01

    Receiver function analysis of teleseismic converted and free surface reflected phases has long been a cornerstone of lithospheric studies. Discontinuities in elastic properties are revealed by deconvolving the incident wavefield from scattered phases and projecting the time differences to depth to form an image. The accuracy of the image is determined to a large extent by the accuracy of the method and background velocity model used, but popular approaches for projecting receiver functions to depth commonly rely on simplifying assumptions of a 1D velocity and planar discontinuities. In tectonically complex regions like subduction zones and rift systems, strong heterogeneity can create an ambiguous tradeoff between the background velocity and the depth of the discontinuities. Furthermore, such structures are apt to create caustics at high frequencies, rendering ray-based methods inadequate. In order to better constrain the background velocity and correctly place the discontinuities at depth, we employ a novel reverse-time migration (RTM) based reflection tomography method. We adapt our reflection tomography from exploration seismology for use with teleseismic phases. Active source methods for exploration have focused on the annihilation of extended images - image gathers formed with different subsurface angle or offset information - as a means of judging the accuracy of the model. Applying these approaches to teleseismic data is untenable because 1) the sparse and uneven distribution of earthquake sources leads to the incomplete construction of extended image, 2) the imperfect separation and source deconvolution of the scattered wavefield render previous error measurements unreliable, and 3) the planar geometry of incoming arrivals makes measures of subsurface offset insensitive to perturbations in the model. To overcome these obstacles, we have developed a flexible approach based on pairwise single-source image correlations. We determine the success of the RTM and thus the accuracy of the background velocity model by cross-correlation of the images produced using different teleseismic sources. Single-source images are created by propagating the incident and scattered wavefields to depth using a Helmholtz operator and combining the by applying an inverse scattering operator. The error function is then comprised of the weighted image correlation power at depth windows. The optimized velocity model is the one that minimizes power in the correlations away from zero depth shift. We develop our inversion scheme using the Augmented Lagrangian method and solve by conjugate gradient on a spline basis. We present details of the method and a 2D application to data from LA RISTRA in the western United States. In order to be effective in 2D, we require teleseismic phases arriving at the array at a broad sweep of incidence angles. With the Andean and Aleutian subduction zones along the strike of the array between 35° and 85° epicentral distance, LA RISTRA provides the ideal illumination for a tomographic inversion.

  8. Heat Flux Estimation in Geothermal Areas Based on the Heat Balance of the Ground Surface

    Microsoft Academic Search

    Mitsuru Sekioka; Kozo Yuhara

    1974-01-01

    The present authors have developed a rapid method for estimation of the difference between geothermal fluxes of two adjacent places, from surface temperatures and some meteorological parameters, based on a heat budget equation for simple vegetation-free ground surfaces. As this method requires simultaneous measurements of the surface temperatures at two Places, an infrared radiation thermometer is the most suitable apparatus

  9. An Electrolysis-Bubble-Actuated Micropump Based on the Roughness Gradient Design of Hydrophobic Surface

    Microsoft Academic Search

    Chih-Ming Cheng; Cheng-Hsien Liu

    2007-01-01

    A novel electrolysis-bubble-actuated micropump based on the roughness gradient design in the microchannel is reported in this paper. This micropump is implemented by taking advantage of both the electrolysis actuation and the surface tension effect. The surface tension effect is controlled via the periodic generation of electrolytic bubbles and the roughness gradient design of microchannel surface, which results in the

  10. A three-dimensional measure of surface roughness based on mathematical morphology

    E-print Network

    Hamprecht, Fred A.

    , IWR, Uni- versity of Heidelberg 1 #12;Abstract In industrial surface characterization tasks, tactile the parameters for quantifying surface roughness based on tactile profile sections, Rz and Ra are the most by parameters which use the whole surface infor- mation made available by state of the art 3D-measuring devices

  11. 3D Brain surface matching based on geodesics and local geometry

    Microsoft Academic Search

    Yongmei Michelle Wang; Bradley S. Peterson; Lawrence H. Staib

    2003-01-01

    The non-rigid registration of surfaces is a complex and difficult task for which there are many important applications, such as comparing shape between deformable objects and com- paring associated function. This paper presents a new approach for brain surface matching by determining the correspondence of 3D point sets between pairs of surfaces. The algorithm is based on shape using a

  12. Automotive crashworthiness design using response surface-based variable screening and optimization

    Microsoft Academic Search

    K. J. Craig; Nielen Stander; D. A. Dooge; S. Varadappa

    2005-01-01

    Purpose – The purpose of this paper is to provide a methodology with which to perform variable screening and optimization in automotive crashworthiness design. Design\\/methodology\\/approach – The screening method is based on response surface methodology in which linear response surfaces are used to create approximations to the design response. The response surfaces are used to estimate the sensitivities of the

  13. Integrity bases for covariants of tetrahedral XY4 molecules. Application to the electric dipole moment surface

    E-print Network

    Recanati, Catherine

    with electric or magnetic properties, for example with the electric dipole moment surface. The symmetrized of the potential energy surface (PES) and of the electric dipole moment surface (EDMS) of the molecule under studyIntegrity bases for covariants of tetrahedral XY4 molecules. Application to the electric dipole

  14. Vacuum-based surface modification of organic and metallic substrates

    NASA Astrophysics Data System (ADS)

    Torres, Jessica

    Surface physico-chemical properties play an important role in the development and performance of materials in different applications. Consequently, understanding the chemical and physical processes involved during surface modification strategies is of great scientific and technological importance. This dissertation presents results from the surface modification of polymers, organic films and metallic substrates with reactive species, with the intent of simulating important modification processes and elucidating surface property changes of materials under different environments. The reactions of thermally evaporated copper and titanium with halogenated polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) are used to contrast the interaction of metals with polymers. Results indicate that reactive metallization is thermodynamically favored when the metal-halogen bond strength is greater than the carbon-halogen bond strength. X-ray post-metallization treatment results in an increase in metal-halide bond formation due to the production of volatile halogen species in the polymer that react with the metallic overlayer. The reactions of atomic oxygen (AO) and atomic chlorine with polyethylene (PE) and self-assembled monolayers (SAMs) films were followed to ascertain the role of radical species during plasma-induced polymer surface modification. The reactions of AO with X-ray modified SAMs are initially the dominated by the incorporation of new oxygen containing functionality at the vacuum/film interface, leading to the production of volatile carbon containing species such as CO2 that erodes the hydrocarbon film. The reaction of atomic chlorine species with hydrocarbon SAMs, reveals that chlorination introduces C-Cl and C-Cl2 functionalities without erosion. A comparison of the reactions of AO and atomic chlorine with PE reveal a maximum incorporation of the corresponding C-O and C-Cl functionalities at the polymer surface. A novel method to prepare phosphorous-containing polymer surfaces through ion implantation of trimethyl phosphine onto PE is presented. Air exposure of the resulting P-implanted PE leads to the surface selective oxidation of phosphorous moieties. P-containing hydrocarbon films are used to model the surface chemical changes of P-containing polymers exposed to AO. Results indicate that oxidized phosphorous species protect the film from AO-induced erosion. The low temperature (<150 K) oxidation of nitrided iron surfaces exposed to oxygen reveal the formation of iron oxynitride (FexNyO z, nitrosonium ions (NO+) as well as nitrite/nitrito and nitrate type species. The production of nitrite/nitrito and nitrate species is taken as evidence for the existence of oxygen insertion chemistry into the iron nitride lattice under these low temperature oxidation conditions. Upon annealing the oxidized iron nitride surface, nitrogen desorbs exclusively as nitric oxide (NO).

  15. Arc Length Based Grid Distribution For Surface and Volume Grids

    NASA Technical Reports Server (NTRS)

    Mastin, C. Wayne

    1996-01-01

    Techniques are presented for distributing grid points on parametric surfaces and in volumes according to a specified distribution of arc length. Interpolation techniques are introduced which permit a given distribution of grid points on the edges of a three-dimensional grid block to be propagated through the surface and volume grids. Examples demonstrate how these methods can be used to improve the quality of grids generated by transfinite interpolation.

  16. Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

    PubMed Central

    do Nascimento, Leonard Euler Andrade Gomes; de Souza, Margareth Maria Gomes; Azevedo, Angela Rita Pontes; Maia, Lucianne Cople

    2014-01-01

    Objective To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating) influences adhesion and formation of Streptococcus mutans colonies. Methods Search strategy: four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME) were selected to search relevant articles covering the period from January 1965 to December 2012. Selection Criteria: in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria. Data collection and analysis: Two reviewers independently extracted data using the keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted. Results The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating) over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design. Conclusions Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating) over colony formation and adhesion of Streptococcus mutans. PMID:24713561

  17. FIELD CHART BRACKETS FOR SPRING STING 2003 (4/23/03) KEY TO FIELD CHARTS

    E-print Network

    White, Stephen

    FIELD CHART BRACKETS FOR SPRING STING 2003 (4/23/03) KEY TO FIELD CHARTS: 8u boys 8u girls 9u boys 10u boys 10u girls 12u boys A-College Park A-Greenbelt. A-College Park A-New Carrollton. A-Lewisdale. E- Bowie. E-Berwyn Heights. E-College Park F-HMB. F-Beltsville #1 12u girls 14u boys 14u girls 18u

  18. Evaluation of the effects of CO 2 laser on debonding of orthodontics porcelain brackets vs. the conventional method

    Microsoft Academic Search

    Azita Tehranchi; Reza Fekrazad; Morvarid Zafar; Behnam Eslami; Katayoun A. M. Kalhori; Norbert Gutknecht

    2011-01-01

    Debonding of ceramic brackets due to their high bond strength and low fracture toughness is one of the clinician’s complications.\\u000a The purpose of this study is to evaluate the effect of a laser on shear bond strength, site of debonding, and ARI index during\\u000a debonding of ceramic brackets and then compare it to the conventional method used for this procedure.

  19. Effect of a fluoride varnish on demineralization adjacent to orthodontic brackets.

    PubMed

    Todd, M A; Staley, R N; Kanellis, M J; Donly, K J; Wefel, J S

    1999-08-01

    Home fluoride regimens have long been used to reduce the amount of demineralization adjacent to orthodontic appliances. In the absence of patient compliance, another method of applying the fluoride must be used. The purpose of this study was to evaluate, in vitro, the ability of a fluoride varnish, Duraflor, to directly inhibit demineralization of enamel surrounding orthodontic brackets. Brackets were bonded to 36 extracted human canines and premolars with a traditional composite resin and randomly assigned to three equal groups of twelve. Group 1 served as the control with no topical application after bonding. Group 2 was treated with a single application of a nonfluoridated placebo varnish. Group 3 was treated with a single application of Duraflor. All groups were cycled in an artificial caries challenge for 1 hour two times daily for 37 days and were brushed with a medium bristled toothbrush to simulate mechanical wear of the varnish. Demineralization of enamel was evaluated in longitudinal buccolingual tooth sections using polarized light microscopy. Both average depth and area of demineralization were measured with a sonic digitizer. ANOVA (P brackets, particularly in patients who exhibit poor compliance with oral hygiene and home fluoride use. PMID:10434089

  20. Operational Satellite-based Surface Oil Analyses (Invited)

    NASA Astrophysics Data System (ADS)

    Streett, D.; Warren, C.

    2010-12-01

    During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible/near IR multispectral satellite imagery as well as a variety of ancillary datasets. Satellite imagery used included ENVISAT ASAR (ESA), TerraSAR-X (DLR), Cosmo-Skymed (ASI), ALOS (JAXA), Radarsat (MDA), ENVISAT MERIS (ESA), SPOT (SPOT Image Corp.), Aster (NASA), MODIS (NASA), and AVHRR (NOAA). Ancillary datasets included ocean current information, wind information, location of natural oil seeps and a variety of in situ oil observations. The analyses were available as jpegs, pdfs, shapefiles and through Google, KML files and also available on a variety of websites including Geoplatform and ERMA. From the very first analysis issued just 5 hours after the rig sank through the final analysis issued in August, the complete archive is still publicly available on the NOAA/NESDIS website http://www.ssd.noaa.gov/PS/MPS/deepwater.html SAB personnel also served as the Deepwater Horizon International Disaster Charter Project Manager (at the official request of the USGS). The Project Manager’s primary responsibility was to acquire and oversee the processing and dissemination of satellite data generously donated by numerous private companies and nations in support of the oil spill response including some of the imagery described above. SAB has begun to address a number of goals that will improve our routine oil spill response as well as help assure that we are ready for the next spill of national significance. We hope to (1) secure a steady, abundant and timely stream of suitable satellite imagery even in the absence of large-scale emergencies such as Deepwater Horizon, (2) acquire a 24 x 7 oil spill response capability at least on a pre-operational basis, (3) acquire improved and expanded ancillary datasets, (4) reduce the number of false positives (analyzed oil that is not actually oil), (5) acquire the ability to reliably differentiate, at least in general qualitative terms, thick oil (“recoverable oil”) from oil sheens, and (6) join our Canadian counterparts (the Integrated Satellite Tracking of Pollution group in Environment Canada) to create a joint North American center for oil spill response.

  1. Satellite Inference of Thermals and Cloud Base Updraft Speeds Based on Retrieved Surface and Cloud Base Temperatures

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Rosenfeld, D.; Li, Z.

    2014-12-01

    Updraft speeds of thermals have always been difficult to measure, despite the significant role they play in transporting pollutants and in cloud formation and precipitation. In this study, updraft speeds measured by Doppler lidar are found to be correlated with the observed planetary boundary layer (PBL) and surface properties in the buoyancy-driven PBL over the Southern Great Plains (SGP) site operated by the U.S. Department of Energy's Atmospheric Radiation Program (ARM). Based on the found relationships, two approaches are proposed to estimate both maximum (Wmax ) and cloud base (Wb ) updraft speeds. The required input data are PBL height, 10-m horizontal wind speed, wind shear, surface skin temperature and 2-m air temperature. The application for remote sensing of updraft speeds in cloud-topped PBL from space was tested by using satellite-retrieved surface and cloud base temperature in combination with European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis data. Validation against lidar-measured updraft speeds indicates the feasibility of retrieving Wmax (root-mean-square error, RMSE, is 0.32 m/s) and Wb (RMSE is 0.42 m/s) for global coverage. This information is essential to advance the understanding of aerosol-cloud interactions. This method does not work for stable or mechanically-driven PBL.

  2. Contour-parallel offset machining for trimmed surfaces based on conformal mapping with free boundary

    Microsoft Academic Search

    Yuwen Sun; Fei Ren; Xinghua Zhu; Dongming Guo

    The parametric surfaces of some manufactured parts are often subjected to the Boolean operation of other objects; generating\\u000a suitable NC tool paths from such trimmed surface remains a challenge. This paper presents a new planar development-based method\\u000a to generate contour-parallel offset paths of trimmed surfaces. To avoid direct frequent identifications and removals of interferences\\u000a of offset curves on 3D-trimmed surface

  3. Functionality of novel black silicon based nanostructured surfaces studied by TOF SIMS

    Microsoft Academic Search

    Ivan Talian; Monika Aranyosiova; Andrej Orinák; Dušan Veli?; Daniel Hasko; Dusan Kaniansky; Renáta Orináková; Jörg Hübner

    2010-01-01

    A functionality of the novel black silicon based nanostructured surfaces (BS 2) with different metal surface modifications was tested by time-of-flight secondary ion mass spectrometry (TOF SIMS). Mainly two surface functions were studied: analytical signal enhancement and analyte pre-ionization effect in SIMS due to nanostructure type and the assistance of the noble metal surface coating (Ag or Au) for secondary

  4. Measuring Concrete Sleeper Rail Seat Pressure Distribution with Matrix Based Tactile Surface Sensors

    E-print Network

    Barkan, Christopher P.L.

    ) is utilizing a matrix based tactile surface sensor (MBTSS) to measure and quantify the forces and pressure1 Measuring Concrete Sleeper Rail Seat Pressure Distribution with Matrix Based Tactile Surface Sensors C.T. Rapp 1 , M.S. Dersch 1 , J.R. Edwards 1 , C.P.L. Barkan 1 , J.R. Mediavilla 2 , B. Wilson 3 1

  5. The Rhetorical Parsing of Unrestricted Texts: A Surface-based Approach

    E-print Network

    Toronto, University of

    The Rhetorical Parsing of Unrestricted Texts: A Surface-based Approach Daniel Marcu* Information well-formed rhetorical structures can be automatically derived by means of surface-form-based algorithms. These algorithms identify discourse usages of cue phrases and breaksentences into clauses, hy

  6. TransforMesh : A Topology-Adaptive Mesh-Based Approach to Surface Evolution

    E-print Network

    Paris-Sud XI, Université de

    TransforMesh : A Topology-Adaptive Mesh-Based Approach to Surface Evolution Andrei Zaharescu1Inerney and Terzopoulos [1] proposed topology adaptive deformable curves and meshes, called T-snakes and T of a surface based on a minimization criterion. The mesh parametrization, while allowing for an accurate

  7. Reconstructing High Quality Face-Surfaces using Model Based Stereo Brian Amberg

    E-print Network

    Vetter, Thomas

    Reconstructing High Quality Face-Surfaces using Model Based Stereo Brian Amberg University of Basel Vetter University of Basel thomas.vetter@uni-basel.ch Abstract We present a novel model based stereo scans. The use of a strong face prior allows us to extract high precision surfaces from stereo data

  8. Physics-Based Shape Modeling And Shape Recovery Using Multiresolution Subdivision Surfaces

    E-print Network

    Qin, Hong

    Physics-Based Shape Modeling And Shape Recovery Using Multiresolution Subdivision Surfaces model based on the multiresolution subdivision surfaces. The proposed model is much more general than changes in shape. Multiresolution analysis on these large meshes becomes a necessity to obtain

  9. Role of surface defects in the electrocatalytic behaviour of copper in base

    Microsoft Academic Search

    L. D. Burke; J. A. Collins

    1999-01-01

    There is increasing evidence, for example, from recently published surface enhanced Raman spectroscopy data, that copper, silver and gold electrode surfaces in base, may exist in an oxidized state at unusually low potentials. In the present work, which was carried out using electrochemical techniques, up to six oxide reduction peaks were recorded for copper in base in the region below

  10. Radar based surface soil moisture retrieval through the combined use of two backscattering models

    Microsoft Academic Search

    Jesús Álvarez-Mozos; Niko E. C. Verhoest; Javier Casali; María González-Audícana

    2005-01-01

    Radar based surface soil moisture retrieval has been subject of intense research during the last decades. However, several difficulties hamper the operational estimation of soil moisture based on actually available space borne sensors. The main difficulty experienced so far consists of the parameterization of other surface characteristics, mainly roughness, which strongly influences the backscattering coefficient and harms the soil moisture

  11. Magnesium-based composites with improved in vitro surface biocompatibility

    PubMed Central

    Huan, Zhiguang; Duszczyk, Jurek

    2010-01-01

    In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity. The observation of the as-cast microstructures of ZK30-BG composites indicated homogeneous dispersion of BG particles in the matrix. SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials. In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy. PMID:20922559

  12. Cyclodextrin-based surface acoustic wave chemical microsensors

    SciTech Connect

    Li, D.Q.; Shi, J.X.; Springer, K.; Swanson, B.I.

    1996-07-01

    Cyclodextrin thin films were fabricated using either self-assembled monolayer (SAM) or solgel techniques. The resulting host receptor thin films on the substrates of surface acoustic wave (SAW) resonators were studied as method of tracking organic toxins in vapor phase. The mass loading of surface-attached host monolayers on SAW resonators gave frequency shifts corresponding to typical monolayer surface coverages for SAM methods and ``multilayer`` coverages for sol-gel techniques. Subsequent exposure of the coated SAW resonators to organic vapors at various concentrations, typically 5,000 parts per millions (ppm) down to 100 parts per billions (ppb) by mole, gave responses indicating middle-ppb-sensitivity ({approximately}50 ppb) for those sensor-host-receptors and organic-toxin pairs with optimum mutual matching of polarity, size, and structural properties.

  13. Characterization and Applications of Affinity Based Surface Modification of Polypyrrole

    NASA Astrophysics Data System (ADS)

    Nickels, Jonathan D.

    I present the characterization and applications of a technique to modify the surface of the conducting polymer, polypyrrole, via a novel, 12-amino acid peptide, THRTSTLDYFVI (T59). This peptide non-covalently binds to the chlorine-doped conducting polymer polypyrrole, allowing it to be used in tethering molecules to polypyrrole for uses such as a scaffold for the treatment of peripheral nerve injury or in surface coatings of neural recording electrodes. I have quantified the binding of this peptide as well as investigating the mechanism of the binding. The equilibrium constant of the binding interaction of PPyCl and the T59 peptide was found through a binding assay to be 92.6 nM, and the off rate was found to be approximately 2.49 s-1, via AFM force spectroscopy. The maximum observed surface density of the peptide was 1.27 +/- 0.42 femtomoles/cm2. Furthermore, my studies suggest that the eighth residue, aspartic acid, is the main contributor of the binding, by interacting with the partially positive charge on the backbone of polypyrrole. I have demonstrated practical applications of the technique in the successful modification of a PPyCl surface with the laminin fragment IKVAV, as well as the so-called stealth molecule poly(ethylene glycol) (PEG). A subcutaneous implant study was performed to confirm that the T59 peptide did not induce any significant reaction in vivo. Significantly, the conductivity of a PPyCl surface was unaffected by this surface modification technique.

  14. Cortical Surface Shape Analysis Based on Spherical Wavelet Transformation

    PubMed Central

    Yu, Peng; Han, Xiao; Ségonne, Florent; Pienaar, Rudolph; Buckner, Randy L.; Golland, Polina; Grant, P. Ellen; Fischl, Bruce

    2015-01-01

    Shape analysis of neuroanatomical structures has proven useful in the study of neuropathology and neurodevelopment. Advances in medical imaging have made it possible to study this shape variation in vivo. In this paper, we propose the use of a spherical wavelet transformation to extract cortical surface shape features, as wavelets can characterize the underlying functions in a local fashion in both space and frequency. Our results demonstrate the utility of the wavelet approach in both detecting the spatial scale and pattern of shape variation in synthetic data, and for quantifying and visualizing shape variations of cortical surface models in subject populations.

  15. Cortical Surface Shape Analysis Based on Spherical Wavelet Transformation

    PubMed Central

    Yu, Peng; Han, Xiao; Ségonne, Florent; Pienaar, Rudolph; Buckner, Randy L.; Golland, Polina; Grant, P. Ellen; Fischl, Bruce

    2015-01-01

    Shape analysis of neuroanatomical structures has proven useful in the study of neuropathology and neurodevelopment. Advances in medical imaging have made it possible to study this shape variation in vivo. In this paper, we propose the use of a spherical wavelet transformation to extract cortical surface shape features, as wavelets can characterize the underlying functions in a local fashion in both space and frequency. Our results demonstrate the utility of the wavelet approach in both detecting the spatial scale and pattern of shape variation in synthetic data, and for quantifying and visualizing shape variations of cortical surface models in subject populations. PMID:17427744

  16. Surface plasmon polariton propagation in organic nanofiber based plasmonic waveguides.

    PubMed

    Leissner, Till; Lemke, Christoph; Jauernik, Stephan; Müller, Mathias; Fiutowski, Jacek; Tavares, Luciana; Thilsing-Hansen, Kasper; Kjelstrup-Hansen, Jakob; Magnussen, Olaf; Rubahn, Horst-Günter; Bauer, Michael

    2013-04-01

    Plasmonic wave packet propagation is monitored in dielectric-loaded surface plasmon polariton waveguides realized from para-hexaphenylene nanofibers deposited onto a 60 nm thick gold film. Using interferometric time resolved two-photon photoemission electron microscopy we are able to determine phase and group velocity of the surface plasmon polariton (SPP) waveguiding mode (0.967c and 0.85c at ?(Laser) = 812nm) as well as the effective propagation length (39 ?m) along the fiber-gold interface. We furthermore observe that the propagation properties of the SPP waveguiding mode are governed by the cross section of the waveguide. PMID:23571915

  17. Surface Electromyographic Onset Detection Based On Statistics and Information Content

    NASA Astrophysics Data System (ADS)

    López, Natalia M.; Orosco, Eugenio; di Sciascio, Fernando

    2011-12-01

    The correct detection of the onset of muscular contraction is a diagnostic tool to neuromuscular diseases and an action trigger to control myoelectric devices. In this work, entropy and information content concepts were applied in algorithmic methods to automatic detection in surface electromyographic signals.

  18. Toward physically based estimation of surface irrigation infiltration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation practitioners continue to use empirical infiltration equations. Theoretical infiltration equations are currently not capable of capturing surface irrigation infiltration behaviour, particularly at short times. An example is shown where the Green-Ampt equation can be adjusted to match fiel...

  19. SURFACE UV RADIATION MONITORING BASED ON GOME AND SCIAMACHY

    Microsoft Academic Search

    Jos van Geffen; Ronald van der A; Michiel van Weele; Marc Allaart; Henk Eskes

    Solar UV radiation reaching the Earth's surface is moni- tored by means of two quantities: the clear-sky UV index at local solar noon and the daily UV dose. Each quan- tity is determined on the basis of two action spectra, de- scribing wavelength dependent biological effects of UV radiation, namely erythema (sunburn) and DNA-damage. The quantities are derived from total

  20. Improved performance of solar cell based on porous silicon surfaces

    Microsoft Academic Search

    Asmiet Ramizy; Wisam J. Aziz; Z. Hassan; Khalid Omar; K. Ibrahim

    2011-01-01

    Porous silicon (PS) surfaces were fabricated by electrochemical etching for both sides of the Si wafer. The objective of the present study is to investigate the PS effect on performance of silicon solar cells. Moreover, enhancement of solar cell efficiency can be obtained by manipulating of the reflected mirrors, and the process is very promising for solar cells manufacturing due

  1. A Silica Gel Based Method for Extracting Insect Surface Hydrocarbons

    E-print Network

    Ramírez, Santiago

    insect cuticle surfaces for subsequent analysis using gas chroma- tography­mass spectrometry (GC odor stored in the memory) (Vander Meer and Morel, 1998; van Zweden and d'Ettorre, 2010 on gas chromatography (GC). The most common method of extraction of CHCs involves soaking or rinsing

  2. Skeleton-Based Seam Computation for Triangulated Surface Parameterization

    E-print Network

    Martin, Ralph R.

    1 , and Ralph Martin2 1 Department of Computer Science and Technology, Tsinghua University Beijing 100084, P. R. China zhuxp@cg.cs.tsinghua.edu.cn, shimin@tsinghua.edu.cn 2 Department of Computer Science an arbitrary topology surface mesh to a single chart. Unfortunately, high distortion occurs when protrusions

  3. Deformation-based surface morphometry applied to gray matter deformation

    E-print Network

    Chung, Moo K.

    surface change. As shown in the previous normal brain develop- ment studies, the growth pattern in developing normal chil- dren is nonuniform over whole brain volume (Chung et al., 2001; Giedd et al., 1999Gill University, Canada e Department of Statistics, Stanford University f Child Psychiatry Branch, National

  4. Multivariate Tensor-based Morphometry on Surfaces: Application to Mapping Ventricular Abnormalities in HIV/AIDS

    PubMed Central

    Wang, Yalin; Zhang, Jie; Gutman, Boris; Chan, Tony F.; Becker, James T.; Aizenstein, Howard J.; Lopez, Oscar L.; Tamburo, Robert J.; Toga, Arthur W.; Thompson, Paul M.

    2010-01-01

    Here we developed a new method, called multivariate tensor-based surface morphometry (TBM), and applied it to study lateral ventricular surface differences associated with HIV/AIDS. Using concepts from differential geometry and the theory of differential forms, we created mathematical structures known as holomorphic one-forms, to obtain an efficient and accurate conformal parameterization of the lateral ventricular surfaces in the brain. The new meshing approach also provides a natural way to register anatomical surfaces across subjects, and improves on prior methods as it handles surfaces that branch and join at complex 3D junctions. To analyze anatomical differences, we computed new statistics from the Riemannian surface metrics - these retain multivariate information on local surface geometry. We applied this framework to analyze lateral ventricular surface morphometry in 3D MRI data from 11 subjects with HIV/AIDS and 8 healthy controls. Our method detected a 3D profile of surface abnormalities even in this small sample. Multivariate statistics on the local tensors gave better effect sizes for detecting group differences, relative to other TBM-based methods including analysis of the Jacobian determinant, the largest and smallest eigenvalues of the surface metric, and the pair of eigenvalues of the Jacobian matrix. The resulting analysis pipeline may improve the power of surface-based morphometry studies of the brain. PMID:19900560

  5. 3D Internal Muscle Activities Imaging Based on MultiChannel Surface EMG Recordings: Surface EMG-Based Muscles Activities Imaging Technique

    Microsoft Academic Search

    Yingchun Zhang; Gerald W. Timm

    2010-01-01

    A surface electromyography (EMG) based muscle activities imaging (sEMG-MAI) approach has been developed using the bioelectrical source reconstruction approach to minimally invasively reconstruct muscle activities in the three dimensional (3D) space of the periurethral muscles (including urethral and anal sphincter, and the surrounding muscles) of the female pelvic floor from multi-channel intra-anal surface EMG recordings. The sEMG-MAI approach is being

  6. Surface plasmon-based infrared spectroscopy for cell biosensing

    NASA Astrophysics Data System (ADS)

    Yashunsky, Victor; Lirtsman, Vladislav; Zilbershtein, Alexander; Bein, Amir; Schwartz, Betty; Aroeti, Benjamin; Golosovsky, Michael; Davidov, Dan

    2012-08-01

    Cell morphology is often used as a valuable indicator of the physical condition and general status of living cells. We demonstrate a noninvasive method for morphological characterization of adherent cells. We measure infrared reflectivity spectrum at oblique angle from living cells cultured on thin Au film, and utilize the unique properties of the confined infrared waves (i.e., surface plasmon and guided modes) traveling inside the cell layer. The propagation of these waves strongly depends on cell morphology and connectivity. By tracking the resonant wavelength and attenuation of the surface plasmon and guided modes we measure the kinetics of various cellular processes such as (i) cell attachment and spreading on different substrata, (ii) modulation of the outer cell membrane with chlorpromazine, and (iii) formation of intercellular junctions associated with progressive cell polarization. Our method enables monitoring of submicron variations in cell layer morphology in real-time, and in the label-free manner.

  7. Broadband omnidirectional antireflection coating based on subwavelength surface Mie resonators

    PubMed Central

    Spinelli, P.; Verschuuren, M.A.; Polman, A.

    2012-01-01

    Reflection is a natural phenomenon that occurs when light passes the interface between materials with different refractive index. In many applications, such as solar cells or photodetectors, reflection is an unwanted loss process. Many ways to reduce reflection from a substrate have been investigated so far, including dielectric interference coatings, surface texturing, adiabatic index matching and scattering from plasmonic nanoparticles. Here we present an entirely new concept that suppresses the reflection of light from a silicon surface over a broad spectral range. A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared. This new antireflection concept relies on the strong forward scattering that occurs when a scattering structure is placed in close proximity to a high-index substrate with a high optical density of states. PMID:22353722

  8. Bionanohybrid based on bioplastic and surface-functionalized carbon nanotubes.

    PubMed

    Singh, Ravina; Ray, Suprakas Sinha

    2010-12-01

    A bionanohybrid consisting of biodegradable/biocompatible poly(butylene succinate) (PBS) and surface-oxidized carbon nanotubes (o-CNTs) was prepared via melt-mixing method. The inherent properties of PBS were concurrently improved by the incorporation of a small amount of o-CNTs. For example, at room temperature, elongation at break increased from approximately 21.2% for pure PBS to approximately 55.1% for the nanohybrid and an increase of about approximately 150% in the value of toughness with moderate improvement in tensile modulus and strength. The dynamic mechanical properties of PBS also increased significantly after nanocomposite formation with o-CNTs. Electron microscopy and Raman spectroscopy were used to investigate the mechanical properties and improvement mechanism of surface-functionalized o-CNTs containing PBS nanohybrid. PMID:21121286

  9. Surface plasmon resonance for cell-based clinical diagnosis.

    PubMed

    Yanase, Yuhki; Hiragun, Takaaki; Ishii, Kaori; Kawaguchi, Tomoko; Yanase, Tetsuji; Kawai, Mikio; Sakamoto, Kenji; Hide, Michihiro

    2014-01-01

    Non-invasive real-time observations and the evaluation of living cell conditions and functions are increasingly demanded in life sciences. Surface plasmon resonance (SPR) sensors detect the refractive index (RI) changes on the surface of sensor chips in label-free and on a real-time basis. Using SPR sensors, we and other groups have developed techniques to evaluate living cells' reactions in response to stimuli without any labeling in a real-time manner. The SPR imaging (SPRI) system for living cells may visualize single cell reactions and has the potential to expand application of SPR cell sensing for clinical diagnosis, such as multi-array cell diagnostic systems and detection of malignant cells among normal cells in combination with rapid cell isolation techniques. PMID:24618778

  10. Surface Plasmon Resonance for Cell-Based Clinical Diagnosis

    PubMed Central

    Yanase, Yuhki; Hiragun, Takaaki; Ishii, Kaori; Kawaguchi, Tomoko; Yanase, Tetsuji; Kawai, Mikio; Sakamoto, Kenji; Hide, Michihiro

    2014-01-01

    Non-invasive real-time observations and the evaluation of living cell conditions and functions are increasingly demanded in life sciences. Surface plasmon resonance (SPR) sensors detect the refractive index (RI) changes on the surface of sensor chips in label-free and on a real-time basis. Using SPR sensors, we and other groups have developed techniques to evaluate living cells' reactions in response to stimuli without any labeling in a real-time manner. The SPR imaging (SPRI) system for living cells may visualize single cell reactions and has the potential to expand application of SPR cell sensing for clinical diagnosis, such as multi-array cell diagnostic systems and detection of malignant cells among normal cells in combination with rapid cell isolation techniques. PMID:24618778

  11. Fabrication of superhydrophobic surface from binary micro-/nano-structure of mullite-whisk-based films

    NASA Astrophysics Data System (ADS)

    Deng, Zhengyan; Yin, Yongjin; Yang, Shengyang; Wang, Cai-Feng; Chen, Su

    2013-11-01

    The wettability of solid surface is a very important property of materials, which depends on both surface chemical composition and the geometry of the solid surface. We herein report a simple and inexpensive method to fabricate superhydrophobic surfaces with the use of mullite whisks (MWs) for the first time. Binary micro-/nano-structural surfaces were created by the incorporation of hydrophilic needlelike MWs with poly( ?-methacryloxypropyltrimethoxysilane) to exhibit hydrophobic behavior, which further showed superhydrophobicity with water contact angle of 152.4±2? after modified with stearic acid. The wettability variation from hydrophilicity to hydrophobicity and superhydrophobicity during the assembly process are discussed based on the scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and contact-angle system. The superhydrophobicity of the surface could be attributed to the hierarchical microstructure of the rough surface induced by MWs and low surface energy of stearic acid.

  12. Surface WGM sensor based on a cylindrical dielectric waveguide

    NASA Astrophysics Data System (ADS)

    Yang, Jing Jing; Huang, Ming; Zhang Chen, De; Ding, Hong Wei; Mao, Fu Chun

    2013-01-01

    The dispersion equation of a layered cylindrical dielectric waveguide operating in the whispering gallery mode (WGM) is derived. We demonstrate that when the waveguide is coated with a negative permittivity layer, a surface WGM can be generated. It exposes a strong evanescent field to the ambient substance, rendering the negative permittivity material assisted microring sensor much more sensitive to a slight change in surrounding medium. This opens up an avenue towards designing optical WGM sensors with superior performance.

  13. Construction of cubic Ball surface based on biharmonic partial differentiation equation

    NASA Astrophysics Data System (ADS)

    Saaban, Azizan; Kherd, Ahmad Saleh; Man, Noraziah Haji; Karim, Samsul Ariffin Abdul

    2014-07-01

    This paper will discuss a new method of Ball surface generation from prescribed boundaries based on the partial differential operator. In particular, we focus on the construction of a bicubic Said-Ball surface using biharmonic partial differentiation equation. The main result is that the use of biharmonic Said-Ball surface would enable the overall surface to be generated and controlled based on the boundary curves rather than a set of control points. We illustrate the new method by using several graphical examples.

  14. The effect of perturbations on resistance to sliding in second-order moments comparing two different bracket types

    PubMed Central

    Wong, Justin K; Romanyk, Dan L; Toogood, Roger W; Heo, Giseon; Carey, Jason P

    2014-01-01

    Orthodontic literature has shown all ligation methods to behave similarly in the clinical situation; however, the reasoning behind this still requires further investigation. A novel frictional device able to measure forces at the level of the bracket along with a custom perturbation device was used to investigate the effect of perturbations on resistance to sliding (RS) using conventional and passive ligated brackets. 150 3M Victory Series twins (0.022 slot) and 150 Damon Q brackets (0.022 slot) were tested using an 0.018 x 0.025 stainless steel wire for RS. There were 5 test groups consisting of equal numbers (n=30) representing combinations of high and low amplitude and frequency of perturbations along with a control. Second order angulation tested ranged from 0 to 6 degrees. Results for conventional brackets in the presence of perturbations at 0 degrees showed there was a statistically significant reduction (P<0.001) in RS when compared to controls. At 6 degrees, this difference (P<0.001) was seen in both high perturbation groups and one of the low perturbation groups. For passive ligated brackets, no statistically significant difference between groups was seen at 0 degrees. However, at 6 degrees high perturbation groups both resulted in statistically significant (P<0.001) reductions in RS when compared to controls. From this study it was concluded that passive ligated brackets have a lower RS when compared to conventional ligated brackets under all test conditions and angulations. Also, amplitude of perturbations has a larger role than frequency in reduction of RS values. PMID:25395993

  15. Compact RGBD Surface Models Based on Sparse Coding Michael Ruhnke

    E-print Network

    Anderson, Richard

    is es- sential for a broad variety of robotic applications includ- ing navigation, object recognition landmark-based representations for lo- calization, grid maps for planning, and feature-based repre- sentations for object detection tasks. Instead of having mul- tiple and potentially redundant representations

  16. Symbolic algorithms for the computation of Moshinsky brackets and nuclear matrix elements

    NASA Astrophysics Data System (ADS)

    Ursescu, D.; Tomaselli, M.; Kuehl, T.; Fritzsche, S.

    2005-12-01

    To facilitate the use of the extended nuclear shell model (NSM), a FERMI module for calculating some of its basic quantities in the framework of MAPLE is provided. The Moshinsky brackets, the matrix elements for several central and non-central interactions between nuclear two-particle states as well as their expansion in terms of Talmi integrals are easily given within a symbolic formulation. All of these quantities are available for interactive work. Program summaryTitle of program:Fermi Catalogue identifier:ADVO Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVO Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computer for which the program is designed and others on which is has been tested:All computers with a licence for the computer algebra package MAPLE [Maple is a registered trademark of Waterloo Maple Inc., produced by MapleSoft division of Waterloo Maple Inc.] Instalations:GSI-Darmstadt; University of Kassel (Germany) Operating systems or monitors under which the program has beentested: WindowsXP, Linux 2.4 Programming language used:MAPLE 8 and 9.5 from MapleSoft division of Waterloo Maple Inc. Memory required to execute with typical data:30 MB No. of lines in distributed program including test data etc.:5742 No. of bytes in distributed program including test data etc.:288 939 Distribution program:tar.gz Nature of the physical problem:In order to perform calculations within the nuclear shell model (NSM), a quick and reliable access to the nuclear matrix elements is required. These matrix elements, which arise from various types of forces among the nucleons, can be calculated using Moshinsky's transformation brackets between relative and center-of-mass coordinates [T.A. Brody, M. Moshinsky, Tables of Transformation Brackets, Monografias del Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 1960] and by the proper use of the nuclear states in different coupling notations. Method of solution:Moshinsky's transformation brackets as well as two-nucleon matrix elements are provided within the framework of MAPLE. The transformation brackets are evaluated recursively for a given number of shells and utilized for the computation of the two-particle matrix elements for different coupling schemes and interactions. Moreover, a simple notation has been introduced to handle the two-particle nuclear states in ll-, LSJ-, and jj-coupling, both in the center-of-well and the relative and center-of-mass coordinates. Restrictions onto the complexity of the problem:The program supports in principle an arbitrary number of shell states with the only limitation given by the computer resources themselves. Typically, the time requirements for the recursive computation of the Moshinsky brackets and matrix elements increase rapidly with the number of the allowed shell states but can be reduced significantly by the pre-calculation of the transformation brackets. Unusual features of the program:Moshinsky brackets are computed and provided in either numeric, algebraic or some symbolic form. In addition, the two-particle matrix elements are calculated for a scalar potential, spin-orbit coupling and tensorial forces, both in floating-point and algebraic notation. All two-particle matrix elements are expressed in terms of the Talmi integrals but can be evaluated also explicitly for several predefined types of the interaction. To simplify the handling of the program, a short but very powerful notation has been introduced which help the user to deal with the two-particle states in various coupling notations. The main commands of the current version of the program are described in detail in Appendix B. Typical running time:The computation of all Moshinsky brackets in floating-point notation, up to ?=6, takes about 5 s at a 2.26 GHz Intel Pentium IIII processor with 512 MB; in algebraic form, the same computations take about 13 s. Similarly, the computation of these brackets up to ?=10 requires in numeric and algebraic form about 5 and 15 min, respectively. Once the

  17. Hierarchical construction of stratigraphic elements in surface-based reservoir models

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Xu, S.; Mukerji, T.

    2013-12-01

    We present a surface-based simulation algorithm connecting stratigraphic hierarchy with surface-based reservoir models through statistical metrics. Geostatistical simulation algorithms provide tools for modeling spatial complexity and the resulting uncertainties for energy resource assessments. As a new family within a wide array of stochastic geological models, surface-based models and rule-based algorithms effectively represent stratigraphic responses to geological events in both time and space by assigning depositional and erosional surfaces with predefined geometries and rules. Recent advances in surface-based modeling focus on simulating morphological evolution of deep-water depositional systems and constraining models to available well and seismic data. However, especially in deep-water plays, scarce well data can only bring information about local stratal features rather than relatively general information such as hierarchy or organization, when these features are below seismic resolution. Without such information, surface-based models lack geological realism and may not be reliable even when conditioned to data. Our proposed surface-based simulation algorithm links stratigraphic hierarchy with surface-based reservoir modeling through spatial statistical tools. Ripley's K-function is used to quantitatively describe the stratigraphic distribution patterns of channel deposits. We also use the compensation index metric for quantifying the strength of compensational stacking in stratigraphic elements. These two metrics help us to extract information about sedimentary hierarchy and element organization from a set of experimental strata, and bridge physical tank experiments with numerical models. We utilize these two geostatistical metrics in conjunction with a surface-based simulation algorithm to 1) integrate clustering and compensational stacking patterns of channel deposits into reservoir modeling 2) make numerical models represent a stratigraphic hierarchical framework comparable to physical tank experiments 3) explore a means of imparting stochastic structures to models and improving geological realism. These models can be used to better assess subsurface spatial uncertainty.

  18. Chromium boron surfaced nickel-iron base alloys

    NASA Technical Reports Server (NTRS)

    Rashid, James M. (Inventor); Friedrich, Leonard A. (Inventor); Freling, Melvin (Inventor)

    1984-01-01

    Chromium boron diffusion coatings on nickel iron alloys uniquely provide them with improvement in high cycle fatigue strength (up to 30%) and erosion resistance (up to 15 times), compared to uncoated alloy. The diffused chromium layer extends in two essential concentration zones to a total depth of about 40.times.10.sup.-6 m, while the succeeding boron layer is limited to 50-90% of the depth of the richest Cr layer nearest the surface. Both coatings are applied using conventional pack diffusion processes.

  19. Shore-based Photogrammetry of Surface Oil Films

    NASA Astrophysics Data System (ADS)

    Whitefield, J.; Record, N.; Pershing, A. J.

    2010-12-01

    Naturally occurring oil slicks are commonly visible in coastal waters. These slicks are suitable proxies for fuel oil spills. We took advantage of these naturally occurring slicks by developing a low-cost system to measure these features and monitor their movement. The use of low-cost digital cameras and a mapping program produces georectified animations of surface features, which can then be used to model surface oceanography, including currents and fine-scale processes such as Langmuir cells. A digital SLR camera was mounted on a bridge overlooking Portland Harbor, and it took still images every minute during daylight hours. Images were then averaged over a five minute period in order to reduce small scale variations such as boat traffic and wind waves. These mean images were then normalized to a Z-score, with the range restricted to +/- 2 standard deviations about the mean, and a threshold of approximately the lower third was used to identify slick regions. It then became possible to create a two dimensional histogram showing the probability of a slick occurring at each lat/long pixel by summing matrices over a given period. The histograms could then be constrained to various stages in the tidal cycle (e.g. high or low water), or to specific weather conditions, thus creating an atlas showing the behavior of surface features. This atlas can then be used to improve planning and pre-sighting for oil spill response in both Portland Harbor and further afield. We also found that the algorithm could also be used in other low-cost situations. Because the image is currently set to detect areas that are relatively lighter than surrounding waters, ice in the harbor showed up clearly. A digital SLR system like the one used here could therefore be used to implement a low-cost ice monitoring station. Another potential use is in red tide monitoring, which is currently being developed. Perhaps most usefully, after detecting and highlighting surface features, these highlights can be used in particle image velocimetry to model, track and interpret small scale oceanographic features for considerably lower cost and higher spatial resolutions than the current generation of many remote sensing platforms.

  20. Field-based Metabolomics for Assessing Contaminated Surface Waters

    EPA Science Inventory

    Metabolomics is becoming well-established for studying chemical contaminant-induced alterations to normal biological function. For example, the literature contains a wealth of laboratory-based studies involving analysis of samples from organisms exposed to individual chemical tox...

  1. Version 2 Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF2)

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.; Shie, Chung-Lin; Starr, David O'C. (Technical Monitor)

    2002-01-01

    Information on the turbulent fluxes of momentum, moisture, and heat at the air-sea interface is essential in improving model simulations of climate variations and in climate studies. We have derived a 13.5-year (July 1987-December 2000) dataset of daily surface turbulent fluxes over global oceans from the Special Sensor Mcrowave/Imager (SSM/I) radiance measurements. This dataset, version 2 Goddard Satellite-based Surface Turbulent Fluxes (GSSTF2), has a spatial resolution of 1 degree x 1 degree latitude-longitude and a temporal resolution of 1 day. Turbulent fluxes are derived from the SSM/I surface winds and surface air humidity, as well as the 2-m air and sea surface temperatures (SST) of the NCEP/NCAR reanalysis, using a bulk aerodynamic algorithm based on the surface layer similarity theory.

  2. A surface intrinsic feature based method (SIFBM) for the characterization of optical microstructure

    NASA Astrophysics Data System (ADS)

    Cheung, C. F.; Kong, L. B.; Lee, W. B.; To, S.

    2008-12-01

    Optical microstructures are small scale topologies which are generally classified as grooves, pyramids, microlens arrays, lenticulations, echells, etc. They are widely used in advanced optics applications. Currently, there is lack of methods for the characterization of surface quality for optical microstructures with sub-micromenter form accuracy and surface finish in the nanometer range. This paper presents a Surface Intrinsic Feature Based Method (SIFBM) which makes use of surface intrinsic properties such as curvatures, normal vectors, torsion, intrinsic frames, etc. They are mapped as special images and image processing techniques are then employed to conduct image registration or correspondences searching by some algorithms such as correlation functions. The surface matching is optimized by corresponding vectors deviations. In the present study, a prototype surface characterization system has been built based on the SIFBM. Primary experimental work has been conducted to validate the proposed method. The results demonstrate that the SIFBM has potential advantages over existing methods.

  3. Microstructure and surface properties of lignocellulosic-based activated carbons

    NASA Astrophysics Data System (ADS)

    González-García, P.; Centeno, T. A.; Urones-Garrote, E.; Ávila-Brande, D.; Otero-Díaz, L. C.

    2013-01-01

    Low cost activated carbons have been produced via chemical activation, by using KOH at 700 °C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp2 content ? 95% and average mass density of 1.65 g/cm3 (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m2/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm2) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  4. Reflectance-Based Sensor Validation Over Ice Surfaces

    NASA Technical Reports Server (NTRS)

    Jaross, Glen; Dodge, James C. (Technical Monitor)

    2003-01-01

    During this period work was performed in the following areas. These areas are defined in the Work Schedule presented in the original proposal: BRDF development, Data acquisition and processing, THR Table generation and Presentations and Publications. BRDF development involves creating and/or modifying a reflectance model of the Antarctic surface. This model must, for a temporal and spatial average, be representative of the East Antarctic plateau and be expressed in terms of the three standard surface angles: solar zenith angle (SolZA), view zenith angle (SatZA), and relative azimuth angle (RelAZ). We successfully acquired a limited amount of NOAA-9 AVHRR data for radiance validation. The data were obtained from the Laboratory for Terrestrial Physics at Goddard Space Flight Center. We developed our own reading and unpacking software, which we used to select Channel 1 data (visible). We then applied geographic subsetting criteria (same as used for TOMS), and wrote only the relevant data to packed binary files. We proceeded with analysis of these data, which is not yet complete.

  5. Hexafluorozirconic Acid Based Surface Pretreatments: Characterization and Performance Assessment

    SciTech Connect

    Adhikari, Saikat [Ohio State University; Unocic, Kinga A [ORNL; Zhai, Yumei [Ohio State University; Frankel, Gerald [Ohio State University; Zimmerman, John [Henkel Corp; Fristad, W [Henkel Corp

    2010-01-01

    A new phosphate-free pretreatment from Henkel Corp. named TecTalis , was investigated. The treatment bath is composed of dilute hexafluorozirconic acid with small quantities of non-hazardous components containing Si and Cu. The performance of treated steel was compared to samples treated in a phosphate conversion coating bath, in simple hexafluorozirconic acid and in TecTalis without the addition of the Cu containing component. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to characterize the coating surface morphology, structure and composition. A Quartz Crystal Microbalance (QCM) was used for studying film growth kinetics on thin films of pure Fe, Al and Zn. Electrochemical Impedance Spectroscopy (EIS) was performed on treated and painted steel for studying long-term corrosion performance of the coatings. The phosphate-free coating provided long-term corrosion performance comparable to that of phosphate conversion coatings. The coatings uniformly cover the surface in the form of 10-20 nm sized nodules and clusters of these features up to 500 nm in size. The coatings are usually about 20-30 nm thick and are mostly composed of Zr and O with enrichment of copper at randomly distributed locations and clusters.

  6. CO2 laser as auxiliary in the debonding of ceramic brackets.

    PubMed

    Macri, Rodrigo Teixeira; de Lima, Fabrício Augusto; Bachmann, Luciano; Galo, Rodrigo; Romano, Fábio Lourenço; Borsatto, Maria Cristina; Matsumoto, Mírian Aiko Nakane

    2014-11-20

    This study evaluated the temperature in the bonding composite and in the pulp chamber, the shear bond strength after the irradiation of CO2 lasers, and the Adhesive Remnant Index (ARI) after debonding of ceramic bracket. A hundred and five premolars were used: 30 to evaluate the temperature and 75 to test the resistance to shear and the ARI. To assess the temperature, different irradiation times (3 and 5 s), pulse duration (0.001 and 0.003 s), and output power (5, 8, and 10 W) were tested (total of 12 groups). During all the irradiation, specimens were immersed in thermal bath water at 37 °C. In the test and ARI evaluation, premolars were divided into five groups (n?=?15) and were submitted to the following regimens of CO2 laser irradiation: I (5 W, pulse duration?=?0.01 s, application time?=?3 s), II (5 W, 0.03 s, 3 s), III (8 W, 0.01 s, 3 s), and IV (1 0 W, 0.01 s, 3 s). Group C (control) was not subjected to irradiation. ARI was measured after debonding of the bracket. Following irradiation of the lasers, the pulpal temperature was not higher than 5.5 °C in four of the study groups. Results were submitted to the ANOVA and Duncan's test. CO2 laser irradiation regimen IV was one in which the strength of debonding is 7.33 MPa. Therefore, CO2 laser may aid removal of ceramic brackets; it decreased the bond strength without increasing the excessive temperature excessively. PMID:25410302

  7. Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets

    PubMed Central

    Britto, Fernanda Alves Rodrigues; Lucato, Adriana Simoni; Valdrighi, Heloisa Cristina; Vedovello, Sílvia Amélia Scudeler

    2015-01-01

    OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20): Group 1, control group (without bleaching); Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each) and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI) was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa) were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa) showed significantly higher bond strength than Group 1 (19.19 MPa), Group 2 (20.59 MPa) and Group 4 (23.25 MPa), but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel. PMID:25992987

  8. Mesh Optimisation Using Edge Information in Feature-Based Surface Reconstruction

    Microsoft Academic Search

    Jun Liu; Roger J. Hubbold

    2006-01-01

    One of the most challenging and fundamental problems in computer vision is to reconstruct a surface model given a set of uncalibrated 2D images. Well-established Structure from Motion (SfM) algorithms of- ten result in a sparse set of 3D surface points, but surface modelling based on sparse 3D points is not easy. In this paper, we present a new method

  9. Surface roughness prediction based on processing parameters in abrasive jet finishing with grinding wheel as restraint

    Microsoft Academic Search

    Li Changhe; Mao Weiping; Du Chao; Liu Zhanrui

    2010-01-01

    Based on the modeling and experiments concerning the surface roughness in abrasive jet finishing with grinding wheel as restraint, the effect of abrasive size, abrasive fluid concentration, machining cycles, wheel velocity and carrier fluid on machined surface quality was investigated. Surface grinder KP-36 was employed in a jet machining experiment conducted with W18Cr4V and 40Cr materials, profilometer TALYSURF was used

  10. Land-surface emissivity maps based on MSG\\/SEVIRI information

    Microsoft Academic Search

    Leonardo F. Peres; Carlos C. DaCamara

    Retrieval of land-surface temperature (LST) using data from MSG\\/SEVIRI requires adequate estimates of land-surface emissivity (LSE). In this context LSE maps for SEVIRI channels IR3.9, IR8.7, IR10.8, and IR12.0 were developed based on the vegetation cover method. A broadband LSE map (3-14 ?m) was also developed for estimating long-wave surface fluxes that may prove to be useful in both energy

  11. Surface modification methods to improve behavior of biosensor based on imaging ellipsometry

    NASA Astrophysics Data System (ADS)

    Niu, Yu; Jin, Gang

    2013-09-01

    Surface modifications not only perform functions as ligand immobilization and biosensing interface formation, but also play a crucial role for inhibiting noise and enhance biosensor signal. After years of development, several surface modification methods designed for the biosensor based on imaging ellipsometry have become more and more practical and already been successfully implemented in the detection of various biomolecules. Some typical surface modification approaches are reviewed.

  12. Change in the bisphenol A content in a polycarbonate orthodontic bracket and its leaching characteristics in water.

    PubMed

    Watanabe, M; Hase, T; Imai, Y

    2001-12-01

    The change in the bisphenol A (BPA) content in a polycarbonate (PC) orthodontic bracket and its leaching characteristics were studied by immersing the bracket in water because BPA has been the matter of controversy in dentistry due to its estrogenic potential. PC brackets were placed in water at 37 degrees C and 60 degrees C and the BPA content in the bracket and the amount of BPA released into the water were analyzed at appropriate intervals by high performance liquid chromatography. The BPA content increased in the water with time and was 3.8-fold after 12 months at 37 degrees C and 12.4-fold after 14 weeks at 60 degrees C compared with the virgin value. The rate of BPA release also increased with time. The results suggested that BPA was released from the bracket time-dependently in the oral cavity. However, it was assessed that little or no estrogenic effect due to the released BPA is expected in the human body. PMID:11915629

  13. From Dirac Notation to Probability Bracket Notation: Time Evolution and Path Integral under Wick Rotations

    E-print Network

    Wang, Xing M

    2009-01-01

    In this article, we continue to investigate the application of Probability Bracket Notation (PBN). We show that, under Special Wick Rotation (caused by imaginary-time rotation), the Schrodinger equation of a conservative system and its path integral in Dirac rotation are simultaneously shifted to the master equation and its Euclidean path integral of an induced micro diffusion in PBN. Moreover, by extending to General Wick Rotation and using the anti-Hermitian wave-number operator, we execute the path integral in Dirac notation side-by-side with the Euclidean path integral in PBN, and derive the Euclidean Lagrangian of induced diffusions and Smoluchowski equation.

  14. From Dirac Notation to Probability Bracket Notation: Time Evolution and Path Integral under Wick Rotations

    E-print Network

    Xing M. Wang

    2009-01-30

    In this article, we continue to investigate the application of Probability Bracket Notation (PBN). We show that, under Special Wick Rotation (caused by imaginary-time rotation), the Schrodinger equation of a conservative system and its path integral in Dirac rotation are simultaneously shifted to the master equation and its Euclidean path integral of an induced micro diffusion in PBN. Moreover, by extending to General Wick Rotation and using the anti-Hermitian wave-number operator, we execute the path integral in Dirac notation side-by-side with the Euclidean path integral in PBN, and derive the Euclidean Lagrangian of induced diffusions and Smoluchowski equation.

  15. VBGVBG3/7/2006MODIFIED LEAK DETECTOR BRACKET1 2. WELDING & INSPECTIONS SHALL BE PERFORMED

    E-print Network

    McDonald, Kirk

    MATERIAL LENGTH 12 1 BENT BRACKET, .75 WIDE X .10 THK SS - 304L, ASTM A240 --- 11 1 PLATE, 39.50 x 70.75 x .250 SS - 304L, ASTM A240 70.75 10 2 ROUND, .38 OD x 4.25 SS - 304L, ASTM A276 4.25 9 1 PLATE, 37.50 x 37.00 x .25 SS - 304L, ASTM A240 37.50 8 1 PLATE, 37.00 x 69.25 x .25 SS - 304L, ASTM A240 69.25 7 2

  16. Probability Bracket Notation: the Unified Expressions of Conditional Expectation and Conditional Probability in Quantum Modeling

    E-print Network

    Xing M. Wang

    2009-11-07

    After a brief introduction to Probability Bracket Notation (PBN), indicator operator and conditional density operator (CDO), we investigate probability spaces associated with various quantum systems: system with one observable (discrete or continuous), system with two commutative observables (independent or dependent) and a system of indistinguishable non-interacting many-particles. In each case, we derive unified expressions of conditional expectation (CE), conditional probability (CP), and absolute probability (AP): they have the same format for discrete or continuous spectrum; they are defined in both Hilbert space (using Dirac notation) and probability space (using PBN); and they may be useful to deal with CE of non-commutative observables.

  17. Probability Bracket Notation, Term Vector Space, Concept Fock Space and Induced Probabilistic IR Models

    E-print Network

    Xing M. Wang

    2011-06-19

    After a brief introduction to Probability Bracket Notation (PBN) for discrete random variables in time-independent probability spaces, we apply both PBN and Dirac notation to investigate probabilistic modeling for information retrieval (IR). We derive the expressions of relevance of document to query (RDQ) for various probabilistic models, induced by Term Vector Space (TVS) and by Concept Fock Space (CFS). The inference network model (INM) formula is symmetric and can be used to evaluate relevance of document to document (RDD); the CFS-induced models contain ingredients of all three classical IR models. The relevance formulas are tested and compared on different scenarios against a famous textbook example.

  18. Forced eruption without orthodontic brackets using fiber reinforced composite prostheses: a case report.

    PubMed

    Mete, J J; Dange, S P; Khalikar, A N; Vaidya, S P

    2012-09-01

    Maintenance of periodontal health is one of the most important factors governing success of the restoration and longevity of teeth. For proper maintenance of periodontal health, the biologic width functions as a protective barrier against the entrance of microorganisms in to the internal medium of the periodontal ligament and osseous connective tissue. This clinical case describes a technique to reestablish the biologic width surrounding a fractured central incisor by forced eruption without orthodontic brackets, using fibre reinforced composite prostheses. Main advantages of using fibre reinforced composite prostheses are aesthetic maintenance during the treatment period, no need for occlusal adjustments, simplicity, low cost, and stability. PMID:23101175

  19. Speaker-Adaptive Speech Recognition Based on Surface Electromyography

    NASA Astrophysics Data System (ADS)

    Wand, Michael; Schultz, Tanja

    We present our recent advances in silent speech interfaces using electromyographic signals that capture the movements of the human articulatory muscles at the skin surface for recognizing continuously spoken speech. Previous systems were limited to speaker- and session-dependent recognition tasks on small amounts of training and test data. In this article we present speaker-independent and speaker-adaptive training methods which allow us to use a large corpus of data from many speakers to train acoustic models more reliably. We use the speaker-dependent system as baseline, carefully tuning the data preprocessing and acoustic modeling. Then on our corpus we compare the performance of speaker-dependent and speaker-independent acoustic models and carry out model adaptation experiments.

  20. The localized surface plasmon resonances based on a Bragg reflector

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Liu, Yumin; Yu, Zhongyuan; Ye, Chunwei; Lv, Hongbo; Shu, Changgan

    2014-09-01

    In this paper, we present the theoretical analysis on how the wavelength of the localized surface plasmon resonances of gold nanoparticle can lead shift for the resonance wavelength. In our results, we calculate the scattering cross-section, the absorption cross-section and the field enhancement due to the nanoparticle. Numerical simulation were done using the finite element method (FEM). The work that we do here is different from the previous work because we use the Bragg reflector as a substrate. The Bragg reflector has a property of high reflectivity in some certain frequency bandwidth because of its periodic structure. The coherence interference of the Bragg reflector contributes to the plasmon resonances and results in some special character for a wide variety application, from sensing to photovoltaic. The periodic number of the Bragg reflector substrate and shapes of the nanoparticles are also discussed that result in a shift of the resonance wavelength.

  1. Comparison of landmark-based and automatic methods for cortical surface registration

    Microsoft Academic Search

    Dimitrios Pantazis; Anand Joshi; Jintao Jiang; David W. Shattuck; Lynne E. Bernstein; Hanna Damasio; Richard M. Leahy

    2010-01-01

    Group analysis of structure or function in cerebral cortex typically involves, as a first step, the alignment of cortices. A surface-based approach to this problem treats the cortex as a convoluted surface and coregisters across subjects so that cortical landmarks or features are aligned. This registration can be performed using curves representing sulcal fundi and gyral crowns to constrain the

  2. Phenology model from surface meteorology does not capture satellite-based greenup estimations

    E-print Network

    Richardson, Andrew D.

    Phenology model from surface meteorology does not capture satellite-based greenup estimations J E R used in phenology studies, but to date that has been little effort to link remotely sensed phenology to surface climate records. In this research, we use a two-parameter spring warming phenology model

  3. Construction of intermediate section profiles of a blade, based on initial profiles predetermined on conical surfaces

    SciTech Connect

    Kaplan, M.P.; Kovalenko, N.N.

    1983-01-01

    The authors describe how to obtain blade profiles of an axial turbine perpendicular to the radial direction and used for producing a working drawing of the blade based on initial profiles designed for the purpose of reducing the energy losses in an annular cascade on conical surfaces approximating the axisymmetrical surfaces of the flow of the working medium.

  4. Triangle Mesh-Based Surface Modeling Using Adaptive Smoothing and Implicit Texture Integration

    E-print Network

    Koschan, Andreas

    Triangle Mesh-Based Surface Modeling Using Adaptive Smoothing and Implicit Texture Integration Y a framework of surface model- ing from multi-view range data. The input to the al- gorithms are triangle meshes, each of which is from a single view range scan. The triangle meshes gener- ated from raw data

  5. Protein Patterning Based on Electrochemical Activation of Bioinactive Surfaces with Hydroquinone-Caged Biotin

    E-print Network

    Kwak, Juhyoun

    Protein Patterning Based on Electrochemical Activation of Bioinactive Surfaces with Hydroquinone@pusan.ac.kr (H.Y.) An efficient attachment and patterning method of proteins on surfaces is crucial to the construction of protein chips1 and bioelectronic devices.2 In the attachment step, the site

  6. A Topological Map Based Approach to Long Range Operation of An Unmanned Surface Vehicle

    E-print Network

    Virginia Tech

    A Topological Map Based Approach to Long Range Operation of An Unmanned Surface Vehicle Aditya S. INTRODUCTION We address the challenge of guidance for unmanned surface vehicles (USVs) that operate in very vehicle trajectories for applications where the vehicle operates in very large environments and for which

  7. Surface-Roughness-Based Virtual Textiles: Evaluation Using a Multi-Contactor Display.

    PubMed

    Philpott, Matthew; Summers, Ian R

    2015-01-01

    Virtual textiles, generated in response to exploratory movements, are presented to the fingertip via a 24-contactor vibrotactile array. Software models are based on surface-roughness profiles from real textiles. Results suggest that distinguishable "textile-like" surfaces are produced, but these lack the necessary accuracy for reliable matching to real textiles. PMID:25781954

  8. A hyper-step DNA computing system based on surface plasmon resonance

    Microsoft Academic Search

    Tsung-Yao Chang; Che-Hsin Lin; Chia-Ning Yang; Chii-Wann Lin

    2007-01-01

    We reported a reusable DNA computing platform for solving satisfiability (SAT) problem based on surface plamon resonance (SPR) technology in this paper. Three different sequences of 18-mer ssDNAs with thiol terminal were first immobilized on the gold surface and then hybridized with their complementary sequences at specific sites via microfluidic channels under room temperature. We also conjugated monoclonal antibody (human

  9. Mapping surface soil moisture using an aircraft-based passive microwave instrument: algorithm and example

    Microsoft Academic Search

    T. J. Jackson; David E. Le Vine

    1996-01-01

    Microwave remote sensing at L-band (21 cm wavelength) can provide a direct measurement of the surface soil moisture for a range of cover conditions and within reasonable error bounds. Surface soil moisture observations are rare and, therefore, the use of these data in hydrology and other disciplines has not been fully explored or developed. Without satellite-based observing systems, the only

  10. Toolpath selection based on the minimum deflection cutting forces in the programming of complex surfaces milling

    Microsoft Academic Search

    L. N. López de Lacalle; A. Lamikiz; J. A. Sánchez; M. A. Salgado

    2007-01-01

    In this paper, a new methodology for the selection of the milling toolpaths on complex surfaces that minimize dimensional errors due to tool defection is presented. In this way, an improvement on the accuracy of milled surfaces is achieved. The methodology can be applied to both three and five axes milling. In the three axes case, it is based on

  11. Surface Plasmon Sensor Based on the Enhanced Light Transmission through Arrays of Nanoholes in Gold Films

    E-print Network

    Brolo, Alexandre G.

    Surface Plasmon Sensor Based on the Enhanced Light Transmission through Arrays of Nanoholes in Gold resonance (SPR) devices. The array of nanoholes is well suited for dense integration in a sensor chip Kretschmann (reflection) arrangement for SPR sensing. Surface plasmon resonance (SPR) sensors are widely used

  12. Evaluation of a Three-Dimensional Micromixer in a Surface-Based Biosensor

    E-print Network

    Leckband, Deborah E.

    Evaluation of a Three-Dimensional Micromixer in a Surface-Based Biosensor Ravi A. Vijayendran over receptors bound to the surface of an optical biosensor. A three-dimensional serpentine plasmon resonance biosensor. The binding kinetics of soluble rabbit IgG to protein A, immobilized on one

  13. 3D MHD Free Surface Fluid Flow Simulation Based on Magnetic-Field Induction Equations

    E-print Network

    California at Los Angeles, University of

    1 3D MHD Free Surface Fluid Flow Simulation Based on Magnetic-Field Induction Equations H.L. HUANG, a penalty factor is introduced in order to force the local divergence free condition of the magnetic fields boundaries is null. These simulation results for lithium film free surface flows under NSTX outboard mid

  14. 3D MHD free surface fluid flow simulation based on magnetic-field induction equations

    E-print Network

    Abdou, Mohamed

    3D MHD free surface fluid flow simulation based on magnetic-field induction equations H.L. Huang 1 in order to force the local divergence free condition of the magnetic fields. The second is that we extend. These simulation results for lithium film free surface flows under NSTX outboard mid-plane magnetic field

  15. Improving satellite-based rainfall estimates over land using spaceborne surface soil moisture retrievals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over land, remotely-sensed surface soil moisture and precipitation accumulation retrievals contain complementary information that can be exploited for the mutual benefit of both products. Here a Kalman filtering based tool is developed that utilizes a time series of spaceborne surface soil moisture ...

  16. PSP: An Advanced Surface-Potential-Based MOSFET Model for Circuit Simulation

    Microsoft Academic Search

    Gennady Gildenblat; Xin Li; Weimin Wu; Hailing Wang; Amit Jha; Ronald van Langevelde; G. D. J. Smit; Andries J. Scholten; Dirk B. M. Klaassen

    2006-01-01

    This paper describes the latest and most advanced surface-potential-based model jointly developed by The Pennsylvania State University and Philips. Specific topics include model structure, mobility and velocity saturation description, further development and verification of symmetric linearization method, recent advances in the computational techniques for the surface potential, modeling of gate tunneling current, inclusion of the retrograde impurity profile, and noise

  17. Interactive Haptic Rendering of Deformable Surfaces Based on the Medial Axis Transform

    E-print Network

    Corso, Jason J.

    Interactive Haptic Rendering of Deformable Surfaces Based on the Medial Axis Transform Jason J for interactive deformation and haptic rendering of viscoelastic surfaces. Objects are de- fined by a discretized haptic and graphic render- ing rates, making it appropriate to model deformation in complex haptic

  18. Theory and experiment of novel frequency selective surface based on substrate integrated waveguide technology

    Microsoft Academic Search

    Guo Qing Luo; Wei Hong; Zhang-Cheng Hao; Bing Liu; Wei Dong Li; Ji Xin Chen; Hou Xing Zhou; K. Wu

    2005-01-01

    A novel frequency selective surface (FSS) based on substrate integrated waveguide (SIW) technology is investigated with simulation and experiment. The periodic unit is made of a SIW cavity with slots on the top and bottom surfaces, and the whole FSS is fabricated on a microwave substrate with standard PCB process. The high-Q property of SIW cavities greatly improved the frequency

  19. Spectral shape-based temporal compositing algorithms for MODIS surface reflectance data

    E-print Network

    1 Spectral shape-based temporal compositing algorithms for MODIS surface reflectance data Philip E Resolution Imaging Spectroradiometer (MODIS) surface reflectance data over a six year period. Algorithm compositing produced the lowest variability for 4 out of 7 MODIS bands, as measured by the root mean square

  20. Bayesian Surface Estimation from Multiple Cameras Using a Prior Based on the Visual Hull

    E-print Network

    Rajpoot, Nasir

    Bayesian Surface Estimation from Multiple Cameras Using a Prior Based on the Visual Hull and its visual hull and surface estimation techniques. It is shown that the new method combines the best features the visual hull. The new method uses an estimate of the visual hull as a prior on the ill-posed problem

  1. Distributed Resolution of a Trajectory Optimization Problem on a MEMS-based Reconfigurable Modular Surface

    E-print Network

    Ingrand, François

    Fig. 1). Blocks move on the surface via electro-permanent magnet technology. Parts are moved on top in a micro-electro-mechanical based modular surface context. The method computes the shortest path between. Self-reconfigurable systems [2-4] made of small Micro-Electro-Mechanical Systems (MEMS) modules can

  2. Surface, Interfacial and Tribological Properties of Cereal-based Amphiphiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch, protein and oil are the major components of most cereals such as corn and soybean. These components, with or without further chemical modification, display a number of important amphiphilic characteristics that are of interest in a number of applications. Cereal-based oils have polar compo...

  3. Biomolecular recognition based on localized surface plasmon resonance of immobilized gold nanorods

    Microsoft Academic Search

    Li Jiang; Xin Li; Qiuqiang Zhan; Jun Qian

    2008-01-01

    A sensitive biosensor based on localized surface plasmon resonance of gold nanorods is fabricated to detect streptavidin. Gold nanorods are immobilized on glass through BSA-biotin instead of chemisorbed method. The detection limit is 1 muM.

  4. Fully automated Liquid Extraction-Based Surface Sampling and Ionization Using a Chip-Based Robotic Nanoelectrospray Platform

    SciTech Connect

    Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2010-01-01

    A fully automated liquid extraction-based surface sampling device utilizing an Advion NanoMate chip-based infusion nanoelectrospray ionization system is reported. Analyses were enabled for discrete spot sampling by using the Advanced User Interface of the current commercial control software. This software interface provided the parameter control necessary for the NanoMate robotic pipettor to both form and withdraw a liquid microjunction for sampling from a surface. The system was tested with three types of analytically important sample surface types, viz., spotted sample arrays on a MALDI plate, dried blood spots on paper, and whole-body thin tissue sections from drug dosed mice. The qualitative and quantitative data were consistent with previous studies employing other liquid extraction-based surface sampling techniques. The successful analyses performed here utilized the hardware and software elements already present in the NanoMate system developed to handle and analyze liquid samples. Implementation of an appropriate sample (surface) holder, a solvent reservoir, faster movement of the robotic arm, finer control over solvent flow rate when dispensing and retrieving the solution at the surface, and the ability to select any location on a surface to sample from would improve the analytical performance and utility of the platform.

  5. Bond of acrylic teeth to different denture base resins after various surface-conditioning methods.

    PubMed

    Lang, Reinhold; Kolbeck, Carola; Bergmann, Rainer; Handel, Gerhard; Rosentritt, Martin

    2012-02-01

    The study examined the bond between different denture base resins and highly cross-linked acrylic denture teeth with different base surface-conditioning methods. One hundred fifty highly cross-linked resin denture teeth (SR-Antaris, No. 11, Ivoclar-Vivadent, FL) were divided into five groups with different surface-conditioning methods of the base surfaces of the teeth (C = control, no surface conditioning, MM = application of methyl methacrylate monomer, SB = sand blasting, SBB = sand blasting + bonding agent, TSS = tribochemical silica coating + silanization). Teeth were bonded to either a cold-cured denture base resin (ProBase Cold, Ivoclar-Vivadent, FL) or heat-cured denture base resins (SR Ivocap Plus, Ivoclar-Vivadent, FL and Lucitone 199, Dentsply, USA). After 24 h of storage in distilled water, compressive load was applied at 90° on the palatal surface of each tooth until fracture. Median failure load ranged between 103 and 257 N for Probase Cold groups, 91 to 261 N for Lucitone 199, and 149 to 320 N for SR Ivocap Plus. For Probase Cold, significant highest failure loads resulted when teeth were treated with SB, SBB, or TSS. For Lucitone 199, significant highest failure loads has been found with MM and TSS treatment. For SR Ivocap Plus, highest failure loads resulted using SBB and TSS. Conditioning of the base surfaces of the teeth prior to denture base processing is highly recommended. Tooth bond is significantly affected by the surface-conditioning method and applied denture base resin. Tribochemical silica coating + silanization method can be recommended for pre-treatment of teeth applying either heat-cured or cold-cured denture base resin. PMID:21181215

  6. Detection of Epileptogenic Cortical Malformations with Surface-Based MRI Morphometry

    Microsoft Academic Search

    Thomas Thesen; Brian T. Quinn; Chad Carlson; Orrin Devinsky; Jonathan Dubois; Carrie R. McDonald; Jacqueline French; Richard Leventer; Olga Felsovalyi; Xiuyuan Wang; Eric Halgren; Ruben Kuzniecky; Mel Feany

    2011-01-01

    Magnetic resonance imaging has revolutionized the detection of structural abnormalities in patients with epilepsy. However, many focal abnormalities remain undetected in routine visual inspection. Here we use an automated, surface-based method for quantifying morphometric features related to epileptogenic cortical malformations to detect abnormal cortical thickness and blurred gray-white matter boundaries. Using MRI morphometry at 3T with surface-based spherical averaging techniques

  7. Microcantilever based distance control between a probe and a surface.

    PubMed

    Molenaar, R; Prangsma, J C; van der Werf, K O; Bennink, M L; Blum, C; Subramaniam, V

    2015-06-01

    We demonstrate a method to control the distance between a custom probe and a sample on a ?m to nm scale. The method relies on the closed-loop feedback on the angular deflection of an in-contact AFM microcantilever. High performance in stability and accuracy is achieved in this method by taking advantage of the small mechanical feedback path between surface and probe. We describe how internal error sources that find their origin in the microcantilever and feedback can be minimized to achieve an accurate and precise control up to 3 nm. In particular, we investigated how hysteresis effects in the feedback caused by friction forces between tip and substrate can be minimized. By applying a short calibration procedure, distance control from contact to several micrometers probe-sample distance can be obtained with an absolute nanometer-scale accuracy. The method presented is compatible with any probe that can be fixed on a microcantilever chip and can be easily built into existing AFM systems. PMID:26133843

  8. Microcantilever based distance control between a probe and a surface

    NASA Astrophysics Data System (ADS)

    Molenaar, R.; Prangsma, J. C.; van der Werf, K. O.; Bennink, M. L.; Blum, C.; Subramaniam, V.

    2015-06-01

    We demonstrate a method to control the distance between a custom probe and a sample on a ?m to nm scale. The method relies on the closed-loop feedback on the angular deflection of an in-contact AFM microcantilever. High performance in stability and accuracy is achieved in this method by taking advantage of the small mechanical feedback path between surface and probe. We describe how internal error sources that find their origin in the microcantilever and feedback can be minimized to achieve an accurate and precise control up to 3 nm. In particular, we investigated how hysteresis effects in the feedback caused by friction forces between tip and substrate can be minimized. By applying a short calibration procedure, distance control from contact to several micrometers probe-sample distance can be obtained with an absolute nanometer-scale accuracy. The method presented is compatible with any probe that can be fixed on a microcantilever chip and can be easily built into existing AFM systems.

  9. Evaluation of surface-potential-based bulk-charge compact MOS transistor model

    Microsoft Academic Search

    Bin B. Jie; Chih-Tang Sah

    2005-01-01

    The existing surface-potential-based compact metal-oxide-semiconductor transistor models are based on the 1978 Brews delta-function charge-sheet approximation, which was derived empirically from the 1966 Pao-Sah drift-diffusion double integral formula. This paper provides a device physics-based derivation of a surface-potential-based compact model by analytical approximation of the double and single bulk-charge integrals of the four one-dimensional components of the six-component 1996 Sah

  10. Tailor-made functional surfaces based on cellulose-derived materials.

    PubMed

    Wang, Chao; Venditti, Richard A; Zhang, Kai

    2015-07-01

    As one of the most abundant natural materials in nature, cellulose has revealed enormous potential for the construction of functional materials thanks to its sustainability, non-toxicity, biocompatibility, and biodegradability. Among many fascinating applications, functional surfaces based on cellulose-derived materials have attracted increasing interest recently, as platforms for diagnostics, sensoring, robust catalysis, water treatment, ultrafiltration, and anti-microbial surfaces. This mini-review attempts to cover the general methodology for the fabrication of functional cellulose surface and a few popular applications including bioactive and non-adhesive (i.e., anti-fouling and anti-microbial) surfaces. PMID:26084889

  11. Pdf modeling for premixed turbulent combustion based on the properties of iso-concentration surfaces

    NASA Technical Reports Server (NTRS)

    Vervisch, L.; Kollmann, W.; Bray, K. N. C.; Mantel, T.

    1994-01-01

    In premixed turbulent flames the presence of intense mixing zones located in front of and behind the flame surface leads to a requirement to study the behavior of iso-concentration surfaces defined for all values of the progress variable (equal to unity in burnt gases and to zero in fresh mixtures). To support this study, some theoretical and mathematical tools devoted to level surfaces are first developed. Then a database of direct numerical simulations of turbulent premixed flames is generated and used to investigate the internal structure of the flame brush, and a new pdf model based on the properties of iso-surfaces is proposed.

  12. Establishing material properties for thin asphalt concrete surfaces on granular bases 

    E-print Network

    Rosson, Barry Thomas

    1985-01-01

    prepared. This analysis has been div1ded into three categories to evaluate the effects of surface modulus and thickness on: (1) the tensile strains at the bottom of the surface, (2) the tensile strains at the top of the surface, (3) the compressive.... Tensile micro-strain contours at the top of the sur- face for 8787 8 ' base modulus and 8-inch base. 0. 365 43 4. 0 75 psi Inflation Pressure 0) c 30 OO 2O I? gp 1. 5 O 1. 0 0 50 100 200 400 600 800 4. 0 125 psi Inflation Pressure OJ EJ 3...

  13. Specular surface measurement based on fringe reflection and study on 3D shape reconstruction technique

    NASA Astrophysics Data System (ADS)

    Zhu, Ronggang; Zhu, Rihong; Song, Qian; Li, Jianxin

    2013-06-01

    In the traditional fringe reflection method for specular surface measurement, the change of phase is only due to the gradient changes. Through the gradient-based phase unwrapping algorithms eventually restored the surface shape. However, due to the approximate nature of the formula itself, the broadness and accuracy of measurement is limited in a certain range within. The actual change in phase comes from the gradient and the surface shape itself together. Therefore, the absolute phase and the surface shape model and the face shape recovery algorithm based on recursion were presented in this paper. Using the model in this paper largely makes up for the deficiencies of the traditional algorithm. A good effect in surface shape recovery has been achieved through the experiment.

  14. Comparative study of friction between metallic and conventional interactive self-ligating brackets in different alignment conditions

    PubMed Central

    Jakob, Sérgio Ricardo; Matheus, Davison; Jimenez-Pellegrin, Maria Cristina; Turssi, Cecília Pedroso; do Amaral, Flávia Lucisano Botelho

    2014-01-01

    Objective The aim of this study was to compare the friction between three bracket models: conventional stainless steel (Ovation, Dentsply GAC), self-ligating ceramic (In-Ovation, Denstply GAC) and self-ligating stainless steel brackets (In-Ovation R, Dentsply GAC). Methods Five brackets were used for each model. They were bonded to an aluminum prototype that allowed the simulation of four misalignment situations (n = 10). Three of these situations occurred at the initial phase (in which a 0.016-in nickel-titanium wire was used): 1. horizontal; 2. vertical; and 3. simultaneous horizontal/vertical. One of the situations occurred at the final treatment phase: 4. no misalignment (in which a 0.019 x 0.025-inch stainless steel rectangular wire was used). The wires slipped through the brackets and friction was measured by a Universal Testing Machine. Results Analysis of variance followed by Tukey's Test for multiple comparisons (? = 0.05) were applied to assess the results. Significant interaction (p < 0.01) among groups was found. For the tests that simulated initial alignment, Ovation® bracket produced the highest friction. The two self-ligating models resulted in lower and similar values, except for the horizontal situation, in which In-Ovation C® showed lower friction, which was similar to the In-Ovation R® metallic model. For the no misalignment situation, the same results were observed. Conclusion The self-ligating system was superior to the conventional one due to producing less friction. With regard to the material used for manufacturing the brackets, the In-Ovation C® ceramic model showed less friction than the metallic ones. PMID:25162570

  15. Surface and core wetting effects of surfactants in oil-based drilling fluids

    Microsoft Academic Search

    L. Skalli; J. S. Buckley; Y. Zhang; N. R. Morrow

    2006-01-01

    Surfactants are used in oil-based drilling fluids to emulsify water and to ensure that cuttings are wetted by oil. The products used are based on drilling conditions and are essentially the same for traditional oil-based and synthetic oil-based fluids. Although much of these surface active materials adsorb on cuttings and filter cake, it is still likely that core samples are

  16. Determination of the Intrinsic Acid-Base Dissociation Constant and Site Density of Ionizable Surface Groups by

    E-print Network

    Chan, Derek Y C

    Determination of the Intrinsic Acid-Base Dissociation Constant and Site Density of Ionizable the surface and the change in the free energy associated with the acid-base reactions of the surface sites, the intrinsic acid-base dissociation constant (Ka i) of the surface sites, andthebackgroundelectrolyte

  17. Surface Roughness Model Based on Force Sensors for the Prediction of the Tool Wear

    PubMed Central

    de Agustina, Beatriz; Rubio, Eva María; Sebastián, Miguel Ángel

    2014-01-01

    In this study, a methodology has been developed with the objective of evaluating the surface roughness obtained during turning processes by measuring the signals detected by a force sensor under the same cutting conditions. In this way, the surface quality achieved along the process is correlated to several parameters of the cutting forces (thrust forces, feed forces and cutting forces), so the effect that the tool wear causes on the surface roughness is evaluated. In a first step, the best cutting conditions (cutting parameters and radius of tool) for a certain quality surface requirement were found for pieces of UNS A97075. Next, with this selection a model of surface roughness based on the cutting forces was developed for different states of wear that simulate the behaviour of the tool throughout its life. The validation of this model reveals that it was effective for approximately 70% of the surface roughness values obtained. PMID:24714391

  18. Regional trends in surface solar radiation derived from satellite-based data sets

    NASA Astrophysics Data System (ADS)

    Trentmann, Jörg; Sanchez-Lorenzo, Arturo; Posselt, Rebekka; Krähenmann, Stefan; Müller, Richard W.; Wild, Martin; Stöckli, Reto; Ahrens, Bodo

    2013-04-01

    The monitoring of the surface solar radiation and the detection of its variability and possible changes is highly relevant for our understanding of the climate system. Clouds and aerosols are the main contributors to the observed changes in the solar energy reaching the surface. Clouds are well observed from satellites, especially during daytime, making satellite-derived data sets of the surface radiation a potentially powerful source of information to assess the spatial structure of surface solar radiation. Surface-based observations, e.g., from the BSRN and GEBA networks, have been used to assess the temporal variability and trend of the surface radiation. Due to the limited spatial distribution of the surface stations, a generalization of the trends derived from measurements at individual stations is difficult. Satellite-derived data of the surface radiation, providing up to global coverage, are available since the 1980s allowing an analysis of the regional variability of temporal changes of the surface radiation. Here, we use surface solar radiation data generated and provided by the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF, www.cmsaf.eu) based on geostationary and polar-orbiting satellites. The ability of the satellite-derived data sets to detect trends is tested and assessed by comparison with surface reference observations in Europe. It is shown that, at least for part of the available time series, the satellite data is stable and can be used to derive trend estimates. Substantial regional differences in the trend of the surface solar radiation are detected across Europe between 1994 and 2005, with strong positive trends over Central Europe (brightening) and negative trends over the Mediterranean Sea (dimming).

  19. Fiber optic surface plasmon resonance based ethanol sensor

    NASA Astrophysics Data System (ADS)

    Verma, Roli; Gupta, Banshi D.

    2014-03-01

    A design of SPR based fiber optic ethanol biosensor is presented by using enzyme alcohol dehydrogenase and nicotinic acid. The sensing probe is fabricated with the coating of 40 nm thin film of silver metal and immobilization of alcohol dehydrogenase and nicotinic acid by gel entrapment method over unclad core of a multimode optical fiber. The SPR spectra of ethanol samples of concentrations ranging from 0 mM to 10 mM prepared in buffer have been recorded. The sensor works on the spectral interrogation technique and operates in the visible range of the spectrum. The SPR curves are blue shifted with the increasing concentration of ethanol and the sensitivity of the sensor decreases with the increasing concentration of ethanol. The sensor has many advantages such as fast response, stability, small probe size, low cost and can be used for remote/online monitoring.

  20. Effects of food surface topography on phage-based magnetoelastic biosensor detection

    NASA Astrophysics Data System (ADS)

    Horikawa, Shin; Chai, Yating; Zhao, Ruiting; Wikle, Howard C.; Chin, Bryan A.

    2014-05-01

    Phage-based magnetoelastic (ME) biosensors have proven useful in rapidly and inexpensively detecting food surface con- tamination. These biosensors are wireless, mass-sensitive biosensors and can be placed directly on food surfaces to detect the presence of target pathogens. Previously, millimeter-scale strip-shaped ME biosensors have been used to demonstrate direct detection of Salmonella Typhimurium on various fresh produce surfaces, including tomatoes, shell eggs, watermel- ons, and spinach leaves. Since the topography of these produce surfaces are different, and the biosensor must come into direct contact with Salmonella bacteria, food surfaces with large roughness and curvatures (e.g., spinach leaf surfaces) may allow the bacteria to avoid direct contact, thereby avoiding detection. The primary objective of this paper is, hence, to investigate the effects of food surface topography on the detection capabilities of the biosensors. Spinach leaf surfaces were selected as model surfaces, and detection experiments were conducted with differently sized biosensors (2 mm, 0.5 mm, and 150 ?m in length). Spinach leaf roughness and curvatures of both adaxial (top) and abaxial (underside) surfaces were measured using a confocal laser scanning microscope. The experimental results showed that in spinach as the sen- sor was made smaller, the physical contact between the biosensors and bacteria were improved. Smaller sensors thereby enhance detection capabilities. When proper numbers of biosensors are used, micron-scale biosensors are anticipated to yield improved limits of detection over previously investigated millimeter-scale biosensors.

  1. Interactive object modelling based on piecewise planar surface patches?

    PubMed Central

    Prankl, Johann; Zillich, Michael; Vincze, Markus

    2013-01-01

    Detecting elements such as planes in 3D is essential to describe objects for applications such as robotics and augmented reality. While plane estimation is well studied, table-top scenes exhibit a large number of planes and methods often lock onto a dominant plane or do not estimate 3D object structure but only homographies of individual planes. In this paper we introduce MDL to the problem of incrementally detecting multiple planar patches in a scene using tracked interest points in image sequences. Planar patches are reconstructed and stored in a keyframe-based graph structure. In case different motions occur, separate object hypotheses are modelled from currently visible patches and patches seen in previous frames. We evaluate our approach on a standard data set published by the Visual Geometry Group at the University of Oxford [24] and on our own data set containing table-top scenes. Results indicate that our approach significantly improves over the state-of-the-art algorithms. PMID:24511219

  2. Wavelength Tunable Single Nanowire Lasers Based on Surface Plasmon Polariton Enhanced Burstein-Moss Effect

    E-print Network

    Xiong, Qihua

    semiconductor NW based solar cells,6 and electrically/optically pumped NW lasers.7-9 For the application as NW transmission through subwavelength hole arrays,24 and SPP amplifiers and lasers,25,26 have been demonstratedWavelength Tunable Single Nanowire Lasers Based on Surface Plasmon Polariton Enhanced Burstein

  3. Nanocluster-based white-light-emitting material employing surface tuning

    DOEpatents

    Wilcoxon, Jess P. (Albuquerque, NM); Abrams, Billie L. (Albuquerque, NM); Thoma, Steven G. (Albuquerque, NM)

    2007-06-26

    A method for making a nanocrystal-based material capable of emitting light over a sufficiently broad spectral range to appear white. Surface-modifying ligands are used to shift and broaden the emission of semiconductor nanocrystals to produce nanoparticle-based materials that emit white light.

  4. Self-oscillation Based Identification and Heading Control for Unmanned Surface Vehicles

    Microsoft Academic Search

    Marco Bibuli; Gabriele Bruzzone; Massimo Caccia; Nikola Miskovic

    The paper demonstrates the use of self-oscillation identification method for heading con- troller tuning of the autonomous unmanned surface vehicle (USV) Charlie. In short, the theory behind self-oscillation identification method is addressed and a model based controller design is described. Two controllers are implemented on the vehicle: controller with Euler backward differ- entiator for yaw rate calculation, Kalman filter based

  5. Surface classification method for a microcomputer-based tutorial system of anatomy

    Microsoft Academic Search

    Angela Klemt; Antonio F. C. Infantosi

    1996-01-01

    For a microcomputer-based tutorial system, algorithms based on Surfaces have been implemented, using classification procedures for spatial position and normals of faces of anatomical structures, in order to establish a priori knowledge of visibility, distance and colouring. With the proposed approach reductions in computing time are always obtained, but the degree depends on the viewing angle. For a lateral-anterior view

  6. Workpiece Surface Integrity and Tool Life Issues When Turning Inconel 718™ Nickel Based Superalloy

    Microsoft Academic Search

    A. R. C. Sharman; J. I. Hughes; K. Ridgway

    2004-01-01

    Inconel 718 is one of a family of nickel-based superalloys which are used extensively in the aerospace industry in the hot sections of gas turbine engines. The literature detailing the effects of varying operating parameters on tool life when machining nickel based superalloys is comprehensive, however, relatively little of this data refers to their effects on machined workpiece surface integrity.

  7. The electrochemical properties of the purine bases : at the interface between biological conjugates to inorganic surfaces

    NASA Technical Reports Server (NTRS)

    Hays, Charles C.

    2003-01-01

    The study of the charge transfer and interfacial reactions of the purine bases in physiological solutions provides valuable knowledge, as these processes are relevant to the origins of life. It has been proposed that the adsorption of the adsorption of the purine bases on an inorganic surface could serve as a template for specifying the arrangement of amino acids in peptides.

  8. Development of a solid surface fluorescence-based sensing system for aluminium monitoring in drinking water

    Microsoft Academic Search

    J. F. García Reyes; P. Ortega Barrales; A. Molina Díaz

    2005-01-01

    A novel, single and robust solid surface fluorescence-based sensing device assembled in a continuous flow system has been developed for the determination of trace amounts of aluminium in water samples. The proposed method is based on the transient immobilization of the target species on an appropriate active solid sensing zone (C18 silica gel). The target species was the fluorogenic chelate,

  9. Tracking Atmospheric Ducts Using Radar Clutter: II. Surface-based Duct Tracking Using Multiple Model

    E-print Network

    Gerstoft, Peter

    the evolution of the range and height-dependent index of refraction using the radar sea clutter. A split-step variability in tracking surface-based ducts in marine and coastal environments. The method tracks fast Fourier transform (FFT) based parabolic equation (PE) approximation to the wave equation is used

  10. Estimation of surface longwave radiation components from ground-based historical net radiation and weather data

    Microsoft Academic Search

    Gi-Hyeon Park; Xiaogang Gao; Soroosh Sorooshian

    2008-01-01

    A methodology for estimating ground upwelling, clear-sky and cloud downwelling longwave radiations (L ?, L sky ?, and L cld ?) and net shortwave radiation (S n ) at 30-min temporal scales based on long-term ground-based net radiations and meteorological observations is described. Components of surface radiation can be estimated from empirical models, cloud radiation models, and remote sensing observations.

  11. Reverse Engineering of Free-Form Surface Based on the Closed-Loop Theory

    PubMed Central

    He, Xue Ming; He, Jun Fei; Wu, Mei Ping; Zhang, Rong; Ji, Xiao Gang

    2015-01-01

    To seek better methods of measurement and more accurate model of reconstruction in the field of reverse engineering has been the focus of researchers. Based on this, a new method of adaptive measurement, real-time reconstruction, and online evaluation of free-form surface was presented in this paper. The coordinates and vectors of the prediction points are calculated according to a Bézier curve which is fitted by measured points. Final measured point cloud distribution is in agreement with the geometric characteristics of the free-form surfaces. Fitting the point cloud to a surface model by the nonuniform B-spline method, extracting some check points from the surface models based on grids and a feature on the surface, review the location of these check points on the surface with CMM and evaluate the model, and then update the surface model to meet the accuracy. Integrated measurement, reconstruction, and evaluation, with the closed-loop reverse process, established an accurate model. The results of example show that the measuring points are distributed over the surface according to curvature, and the reconstruction model can be completely expressed with micron level. Meanwhile, measurement, reconstruction and evaluation are integrated in forms of closed-loop reverse system. PMID:25879078

  12. Reverse engineering of free-form surface based on the closed-loop theory.

    PubMed

    He, Xue Ming; He, Jun Fei; Wu, Mei Ping; Zhang, Rong; Ji, Xiao Gang

    2015-01-01

    To seek better methods of measurement and more accurate model of reconstruction in the field of reverse engineering has been the focus of researchers. Based on this, a new method of adaptive measurement, real-time reconstruction, and online evaluation of free-form surface was presented in this paper. The coordinates and vectors of the prediction points are calculated according to a Bézier curve which is fitted by measured points. Final measured point cloud distribution is in agreement with the geometric characteristics of the free-form surfaces. Fitting the point cloud to a surface model by the nonuniform B-spline method, extracting some check points from the surface models based on grids and a feature on the surface, review the location of these check points on the surface with CMM and evaluate the model, and then update the surface model to meet the accuracy. Integrated measurement, reconstruction, and evaluation, with the closed-loop reverse process, established an accurate model. The results of example show that the measuring points are distributed over the surface according to curvature, and the reconstruction model can be completely expressed with micron level. Meanwhile, measurement, reconstruction and evaluation are integrated in forms of closed-loop reverse system. PMID:25879078

  13. Band-structure-based collisional model for electronic excitations in ion-surface collisions

    SciTech Connect

    Faraggi, M.N. [Instituto de Astronomia y Fisica del Espacio, CONICET, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Gravielle, M.S. [Instituto de Astronomia y Fisica del Espacio, CONICET, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, FCEN, Universidad de Buenos Aires, Buenos Aires (Argentina); Alducin, M.; Silkin, V.M. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Juaristi, J.I. [Departamento de Fisica de Materiales Facultad de Quimicas, UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Unidad de Fisica de Materiales Centro Mixto CSIC-UPV/EHU, Facultad de Quimicas, UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain)

    2005-07-15

    Energy loss per unit path in grazing collisions with metal surfaces is studied by using the collisional and dielectric formalisms. Within both theories we make use of the band-structure-based (BSB) model to represent the surface interaction. The BSB approach is based on a model potential and provides a precise description of the one-electron states and the surface-induced potential. The method is applied to evaluate the energy lost by 100 keV protons impinging on aluminum surfaces at glancing angles. We found that when the realistic BSB description of the surface is used, the energy loss obtained from the collisional formalism agrees with the dielectric one, which includes not only binary but also plasmon excitations. The distance-dependent stopping power derived from the BSB model is in good agreement with available experimental data. We have also investigated the influence of the surface band structure in collisions with the Al(100) surface. Surface-state contributions to the energy loss and electron emission probability are analyzed.

  14. Measurement of Orthodontic Bracket Tie Wing Elastic and Plastic Deformation by Arch Wire Torque Expression Utilizing an Optical Image Correlation Technique

    PubMed Central

    Lacoursiere, Ryan A.; Nobes, David S.; Homeniuk, Darren L. N.; Carey, Jason P.; Badawi, Hisham H.; Major, Paul W.

    2010-01-01

    Orthodontic lingual root movement (torque) is an important aspect of treatment biomechanics and is typically achieved by torsion of a rectangular wire within the orthodontic bracket slot which introduces a force couple. The magnitude of the force moment achieved by wire torsion may be influenced by deformation of the orthodontic bracket. A device utilizing an optical image correlation technique has been developed to accurately quantify bracket slot dimensional changes during application of wire torsion. Simultaneous torque moment magnitude, degrees of wire twist, and bracket slot dimension data can be gathered. Bracket tie wing elastic deformation when loaded was demonstrated and plastic deformation was also observed with a single rotation of the wire. PMID:20948571

  15. Surface roughness of glazed feldspar, alumina, and zirconia-based ceramics Rugosidade das superfícies vitrifi cadas de cerâmicas feldspática, a base de zircônia e a base de alumina

    Microsoft Academic Search

    Karla Zanini KANTORSKI; Luiz Felipe VALANDRO; Roberto SCOTTI; Álvaro DELLA BONA; Marco Antonio BOTTINO

    The aim of this study was to compare the mean surface roughness (Ra) of feldspar-, alumina-, and zirconia-based cera- mics, testing the hypothesis that the feldspathic ceramics have lower average surface roughness (Ra) than the ceramics used for infrastructure. Eight disk specimens (5mm in diameter; 2mm in thickness) of each ceramic material were fabricated according to the manufacturer's specifi cations:

  16. Effect of fluoride varnish on demineralization adjacent to brackets bonded with RMGI cement.

    PubMed

    Schmit, Jason L; Staley, Robert N; Wefel, James S; Kanellis, Michael; Jakobsen, Jane R; Keenan, Peter J

    2002-08-01

    Far too often a less-than-optimal esthetic result occurs after orthodontic treatment due to demineralization of enamel adjacent to fixed orthodontic appliances in patients with inadequate oral hygiene. In vitro studies have shown that a resin-modified glass ionomer (RMGI) cement and a fluoride varnish might help clinicians combat this problem. The purpose of this study was to evaluate, in vitro, the effect of a fluoride-releasing cavity varnish on inhibition of enamel demineralization adjacent to orthodontic brackets bonded with RMGI and composite resin cements. Brackets were bonded to 48 extracted human third molars. Half were bonded with a composite resin (Transbond, 3M Unitek, Monrovia, Calif) and half with an RMGI (Fuji Ortho LC, GC America, Alsip, Ill). Each group was further divided into 2, with half receiving an application of fluoride-releasing varnish (Duraflor, Pharmascience, Montreal, Québec, Canada). The samples were cycled in an artificial caries solution for an hour twice daily for 31 days. After each caries challenge, the teeth were brushed with a soft toothbrush to simulate normal mechanical wear of the varnish. The loss of fluoride varnish was timed. Teeth were sectioned longitudinally and photographed under polarized light microscopy. Mean lesion depth was measured, and analysis of variance (ANOVA) (P bracket. A chi-square test showed that the fluoride varnish was lost significantly faster in samples bonded with Fuji Ortho LC (P =.013). Although the fluoride varnish could not prevent demineralization, it appears to be beneficial in reducing lesion formation. Clinicians should consider applying fluoride varnish on areas of enamel that exhibit demineralization or are at risk of demineralization in patients with poor oral hygiene. PMID:12165766

  17. Surface-data-based haptic rendering for simulation of surgery of closed reduction and internal fixation.

    PubMed

    Cho, Jang Ho; Jung, Hoeryong; Yu, Insik; Lee, Kyungno; Lee, Doo Yong; Ahn, Hyung Soo; Park, Ilhyung; Yeo, Sang Hee; Han, Seung-Ho

    2007-01-01

    This paper presents a surface-data-based haptic rendering method for simulation of surgery of closed reduction and internal fixation (CRIF). Volumetric data is often employed in the simulation of bone surgery because the volume rendering can easily handle information such as density and rigidity of each voxel. However, it is difficult to implement real-time graphics and haptic rendering because of the large computational workload. Therefore, we propose a surface-data-based haptic rendering method for real-time rendering. Mechanical properties and graphics of the inner part of the bone should be modeled in addition to the surface data to simulate drilling into the bone. An algorithm is developed to construct the surface of the drilled hole. This method allows the user of the simulation to feel the varying forces according to the drilled depth. PMID:18001926

  18. Final report of ''Fundamental Surface Reaction Mechanisms in Fluorocarbon Plasma-Based Processing''

    SciTech Connect

    Gottlieb S. Oehrlein; H. Anderson; J. Cecchi; D. Graves

    2004-09-21

    This report provides a summary of results obtained in research supported by contract ''Fundamental Surface Reaction Mechanisms in Fluorocarbon Plasma-Based Processing'' (Contract No. DE-FG0200ER54608). In this program we advanced significantly the scientific knowledge base on low pressure fluorocarbon plasmas used for patterning of dielectric films and for producing fluorocarbon coatings on substrates. We characterized important neutral and ionic gas phase species that are incident at the substrate, and the processes that occur at relevant surfaces in contact with the plasma. The work was performed through collaboration of research groups at three universities where significantly different, complementary tools for plasma and surface characterization, computer simulation of plasma and surface processes exist. Exchange of diagnostic tools and experimental verification of key results at collaborating institutions, both experimentally and by computer simulations, was an important component of the approach taken in this work.

  19. Cloud-Dependent Surface Energy Budgets over the Ocean: Observation-Based and Reanalysis Estimates

    NASA Astrophysics Data System (ADS)

    Wong, S.; L'Ecuyer, T. S.; Fetzer, E. J.

    2014-12-01

    Regional balance of the atmospheric energy budget provides a stringent constraint to evaluate datasets of global energy budgets. Previous studies indicated that satellite-based and reanalysis estimates describe different heating rates in the atmosphere. Compared to the satellite-based heating rates, reanalyses (European Center for Medium Range Weather Forecast Interim, ERA-Interim, and Modern-Era Retrospective Analysis for Research and Applications, MERRA) have larger heating in the tropical convective regimes and smaller cooling in the subtropical subsidence regimes. Many of these discrepancies originate in cloudy regions where different estimation methods give different energy budgets. In this study, we investigate how different components of the surface energy budget depend on cloud properties in the atmosphere. We will also examine the dependence of discrepancies between reanalysis and the satellite-based surface energy budgets on cloud properties. Different satellite-based estimates, including Tropical Rainfall Measuring Mission (TRMM)-based surface shortwave and longwave heat fluxes, NASA Global Energy and Water Cycle Experiment surface energy budget (SRB) shortwave and longwave radiative heat fluxes, Goddard Satellite-based Surface Turbulent Flux (GSSTF)'s sensible and latent heat fluxes, and the objectively-analyzed air-sea fluxes (OAFlux), are collocated with cloud property measurements of Moderate Resolution Imaging Spectroradiometer (MODIS). MODIS cloud optical depth (COD) and cloud top pressure (CTP) are used to identify cloud types. Different components of surface energy budgets from the satellite-based estimates and the discrepancies from their reanalysis counterparts will be presented as functions of COD and CTP for selected regions that represent tropical convective and subtropical subsidence regimes.

  20. III-V-semiconductor-based surface-micromachined catilevers for micro-opto-mechanical systems

    NASA Astrophysics Data System (ADS)

    Mao, Jin; Tong, Hua; Zhou, Dan; Jia, Zhensheng; Wang, Jianhua; Xie, Shizhong

    2001-10-01

    Surface micromachining processes based on III-V compound semiconductors are presented in this paper, in order to develop Micro-Opto-Electro-Mechanical systems (MOEMS). By fabricating micro cantilevers composed of seven InP/Air gap pairs, the major techniques of the surface micromachining are studied, including non-selective and selective etching, rinsing and drying. A severe problem of the sticking phenomena during rinsing and drying is avoided by the implementation of the Critical Point Drying (CPD) method.

  1. Fabrication and tribological properties of super-hydrophobic surfaces based on porous silicon

    Microsoft Academic Search

    Y. H. Liu; X. K. Wang; J. B. Luo; X. C. Lu

    2009-01-01

    In the present work, super-hydrophobic surfaces based on porous silicon (PS) were constructed by the self-assembled molecular films and their tribological properties were investigated. A simple chemical etching approach was developed to fabricate PS with the certain rough microstructure surface, which can be observed by the environmental scanning electron microscopy (ESEM). The hydrocarbon and fluorocarbon alkylsilane molecular films were self-assembled

  2. A Database for the Selection of Surfaces and Materials for Space and Ground-Based Applications

    Microsoft Academic Search

    Susan H. Mccall; Anthony J. Clark; Robyn A. Ellis; Rorik A. Henrikson; Alice E. Piotrowski; Lorraine A. Piotrowski; Michael A. Reid; John W. Rodney; Robert P. Breault; Marshall L. McCall

    \\u000a Stellar Optics Research International Corporation (SORIC) has compiled the world’s largest databank of spectral reflectance\\u000a data and Bi-directional Reflectance Distribution Function (BRDF) data for black, white, reflective and transmissive surfaces\\u000a and materials which are commonly employed within or viewed by groundbased and space-based instrument applications. These surfaces\\u000a and materials, and in particular the black and white colored materials, typically are

  3. Effect of grinding temperatures on the surface integrity of a nickel-based superalloy

    Microsoft Academic Search

    X. P Xu; Y. Q Yu; H. J Xu

    2002-01-01

    An experimental study was carried out to investigate the influence of temperatures on workpiece surface integrity in the surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. The temperature response at the wheel–workpiece interface was measured using a grindable foil\\/workpiece thermocouple. Specimens with different grinding temperatures were obtained through changing the grinding conditions, including the depth of cut,

  4. Optical microcavity based on zero-group-velocity surface modes in photonic crystals

    Microsoft Academic Search

    Min Qiu; Sanshui Xiao

    2005-01-01

    Optical microcavities based on zero-group-velocity surface modes in photonic crystals are studied. It is shown that high quality factors can be easily obtained for such microcavities in photonic crystals. With increasing of the cavity length, the quality factor is gradually enhanced and the resonant frequency converges to that of the zero-group-velocity surface mode in the photonic crystals. Different with other

  5. Avian influenza-DNA hybridization detection using wavelength interrogation-based surface plasmon resonance biosensor

    Microsoft Academic Search

    Shin Ae Kim; Sung June Kim; Sang Hun Lee; Tai Hyun Park; Kyung Min Byun; Sung Guk Kim; M. L. Shuler

    2009-01-01

    A wavelength interrogation-based surface plasmon resonance (SPR) biosensor has been investigated for a detection of avian influenza DNA (AI-DNA). The hybridization reaction between AI-DNA and the immobilized oligonucleotide probe on a gold surface was monitored. The results showed that SPR biosensor can provide a linear detection suitable for quantification of AI-DNA hybridization as well as a large dynamic range. The

  6. A determination of albedos and surface temperatures on Mars from ground-based infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Lellouch, E.; Rosenqvist, J.; Bouchet, P.

    1991-02-01

    Surface temperatures and albedos of the Martian disk have been measured from ground-based infrared spectroscopy, between September and December 1988. As a result, the measured surface temperatures seem to be higher than the Viking temperatures measured in 1977, and closer to the theoretical temperatures calculated from the Viking 1976 (primary mission). This suggests that the Martian dust activity in 1988, at the time of opposition, was probably less intense than in 1977.

  7. Approaches to Protein Resistance on the Polyacrylonitrile-based Membrane Surface: an Overview

    Microsoft Academic Search

    Ling-Shu Wan; Zhi-Kang Xu; Xiao-Jun Huang

    Protein adsorption and\\/or deposition at the surface of polymeric membranes play important roles in membrane separation processes.\\u000a Although polyacrylonitrile-based membranes have been used successfully in many fields, surface modifications to improve the\\u000a protein resistance and hemocompatibility have received considerable interest. Various methods such as copolymerization, grafting,\\u000a physical adsorption, biomacromolecule immobilization, and biomimetic modification, have been explored to build a friendly

  8. 3D surface reconstruction based on combined analysis of reflectance and polarisation properties

    Microsoft Academic Search

    Pablo d'Angelo; Christian Wohler

    2005-01-01

    In this paper we present a novel image-based 3D surface reconstruction technique that incorporates both reflectance and polarisation features into a variational framework. The proposed technique is suitable for single-image and multi-image (photopolarimetric stereo) analysis. It is especially suited for the difficult task of 3D reconstruction of rough metallic surfaces. An error functional consisting of several error terms related to

  9. Triton's surface properties - A preliminary analysis from ground-based, Voyager photopolarimeter subsystem, and laboratory measurements

    NASA Technical Reports Server (NTRS)

    Buratti, B. J.; Lane, A. L.; Gibson, J.; Burrows, H.; Nelson, R. M.; Bliss, D.; Smythe, W.; Garkanian, V.; Wallis, B.

    1991-01-01

    The surface properties of Triton were investigated using data from the ground-based and Voyager photopolarimeter subsystem (PPS) observations of Triton's phase curve. The results indicate that Triton has a high single-scattering albedo (0.96 +/-0.01 at 0.75 micron) and an unusually compacted surface, possibly similar to that of Europa. Results also suggest that Triton's single-particle phase function and the macroscopically rough character of its surface are similar to those of most other icy satellites.

  10. Superhydrophobic Zr-based metallic glass surface with high adhesive force

    NASA Astrophysics Data System (ADS)

    Li, Ning; Xia, Ting; Heng, Liping; Liu, Lin

    2013-06-01

    Micro/nano hierarchical structures were constructed on Zr35Ti30Be26.75Cu8.25 metallic glass surface by silicon moulding and subsequently chemical etching. The as-formed surface exhibited both superhydrophobicity and high adhesive force towards water. The superhydrophobicity is rationalized based on the modified Cassie-Baxter model [A. B. D. Cassie and S. Baxter, Trans. Faraday Soc. 40, 546 (1944)]. The origin of the robust adhesion is described in terms of intermolecular capillary forces. The present results not only provide a method to fabricate superhydrophobic metallic glasses surface but also explore an important industrial application as dry adhesives and transport of liquid microdroplets.

  11. Biodegradable polyester-based microcarriers with modified surface tailored for tissue engineering.

    PubMed

    Privalova, A; Markvicheva, E; Sevrin, Ch; Drozdova, M; Kottgen, C; Gilbert, B; Ortiz, M; Grandfils, Ch

    2015-03-01

    Microcarriers have been proposed in tissue engineering, namely for bone, cartilage, skin, vascular, and central nervous system. Although polyester-based microcarriers have been already used for this purpose, their surface properties should be improved to provide better cell growth. The goal of this study was to prepare microbeads based on poly(D,L-lactide) acid, poly(L-lactide) acid, and to study cell behavior (adhesion, spreading, growth, and proliferation) in function of microbead topography and surface chemistry. To improve L-929 fibroblasts adhesion, microbead surface has been modified with three polycations: chitosan, poly(2-dimethylamino ethylmethacrylate) (PDMAEMA), or chitosan-g-oligolactide copolymer (chit-g-OLA). Although modification of the microbead surface with chitosan and PDMAEMA was performed through physical adsorption on the previously prepared microbeads, chit-g-OLA copolymer was introduced directly during microbead processing. This simple approach (1) bypass the use of an emulsifier (polyvinyl alcohol, PVA); (2) avoid surface "contamination" with PVA molecules limiting a control of the surface characteristics. In vitro study of the growth of mouse fibroblasts on the microbeads showed that both surface topography and chemistry affected cell attachment, spreading, and proliferation. Cultivation of L-929 fibroblasts for 7 days resulted in the formation of a 3D cell-scaffold network. PMID:24832052

  12. Noninvasive probing of the ocean surface using laser-based nonlinear optical methods

    SciTech Connect

    Korenowski, G.M.; Frysinger, G.S.; Asher, W.E. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry

    1992-06-01

    The laser-based nonlinear optical methods of second-harmonic generation and sum-frequency generation have been developed to study the chemical composition and concentration of natural surfactant materials present as slicks on the ocean surface. These noninvasive second-harmonic and sum-frequency generation methods produce signals which originate from only the top few molecular layers of the ocean surface, thereby producing an accurate picture of the ocean surface condition without interference from the bulk ocean chemistry. Chemical specificity of the methods is achieved by tuning the incident laser frequency to coincide with optical absorptions in the surface absorbed materials. We show that laser-based second-order nonlinear optical processes of SHG and SFG provide highly surface selective, noninvasive, in situ probes of the ocean surface. Although only preliminary experiments are reported in this paper, the probes provide important information about the nature of surfactants at the ocean surface and their behavior in response to dynamic forces at the sea/air interface. The future of the probes lies in their further development and use as in situ interfacial spectroscopic techniques.

  13. REVIEW ARTICLE: Trends in interfacial design for surface plasmon resonance based immunoassays

    NASA Astrophysics Data System (ADS)

    Shankaran, Dhesingh Ravi; Miura, Norio

    2007-12-01

    Immunosensors based on surface plasmon resonance (SPR) have become a promising tool in sensor technology for biomedical, food, environmental, industrial and homeland security applications. SPR is a surface sensitive optical technique, suitable for real-time and label-free analysis of biorecognition events at functional transducer surfaces. Fabrication of highly active and robust sensing surfaces is an important part in immunoassays because the quality, quantity, chemistry and topography of the interfacial biomembranes play a major role in immunosensor performance. Eventually, a variety of immobilization methods such as physical adsorption, covalent coupling, Langmuir Blodgett film, polymer thin film, self-assembly, sol gel, etc, have been introduced over the years for the immobilization of biomolecules (antibody or antigen) on the transducer surfaces. The selection of an immobilization method for an immunoassay is governed by several factors such as nature and stability of the biomolecules, target analyte, application, detection principle, mode of signal transduction, matrix complexity, etc. This paper provides an overview of the various surface modification methods for SPR based immunosensor fabrication. The preparation, structure and application of different functional interfacial surfaces have been discussed along with a brief introduction to the SPR technology, biomolecules and detection principles.

  14. Multi-dimensional respiratory motion tracking from markerless optical surface imaging based on deformable mesh registration

    NASA Astrophysics Data System (ADS)

    Schaerer, Joël; Fassi, Aurora; Riboldi, Marco; Cerveri, Pietro; Baroni, Guido; Sarrut, David

    2012-01-01

    Real-time optical surface imaging systems offer a non-invasive way to monitor intra-fraction motion of a patient's thorax surface during radiotherapy treatments. Due to lack of point correspondence in dynamic surface acquisition, such systems cannot currently provide 3D motion tracking at specific surface landmarks, as available in optical technologies based on passive markers. We propose to apply deformable mesh registration to extract surface point trajectories from markerless optical imaging, thus yielding multi-dimensional breathing traces. The investigated approach is based on a non-rigid extension of the iterative closest point algorithm, using a locally affine regularization. The accuracy in tracking breathing motion was quantified in a group of healthy volunteers, by pair-wise registering the thoraco-abdominal surfaces acquired at three different respiratory phases using a clinically available optical system. The motion tracking accuracy proved to be maximal in the abdominal region, where breathing motion mostly occurs, with average errors of 1.09 mm. The results demonstrate the feasibility of recovering multi-dimensional breathing motion from markerless optical surface acquisitions by using the implemented deformable registration algorithm. The approach can potentially improve respiratory motion management in radiation therapy, including motion artefact reduction or tumour motion compensation by means of internal/external correlation models.

  15. Design Study of the GNIRS Bracket Structure Optical Sciences Center, University of Arizona and Gemini 8m Telescopes

    E-print Network

    element analysis is combined with three­dimensional layout techniques to develop an optimized structural operations. Finite element analysis is mainly utilized to develop an optimized structural configurationDesign Study of the GNIRS Bracket Structure Myung Cho Optical Sciences Center, University

  16. Design Study of the GNIRS Bracket Structure Optical Sciences Center, University of Arizona and Gemini 8m Telescopes

    E-print Network

    element analysis is combined with three-dimensional layout techniques to develop an optimized structural operations. Finite element analysis is mainly utilized to develop an optimized structural configurationDesign Study of the GNIRS Bracket Structure Myung Cho Optical Sciences Center, University

  17. Formulation of singular theories in a partial Hamiltonian formalism using a new bracket and multi-time dynamics

    E-print Network

    Steven Duplij

    2014-09-07

    A formulation of singular classical theories (determined by degenerate Lagrangians) without constraints is presented. A partial Hamiltonian formalism in the phase space having an initially arbitrary number of momenta (which can be smaller than the number of velocities) is proposed. The equations of motion become first-order differential equations, and they coincide with those of multi-time dynamics, if a certain condition is imposed. In a singular theory, this condition is fulfilled in the case of the coincidence of the number of generalized momenta with the rank of the Hessian matrix. The noncanonical generalized velocities satisfy a system of linear algebraic equations, which allows an appropriate classification of singular theories (gauge and nongauge). A new antisymmetric bracket (similar to the Poisson bracket) is introduced, which describes the time evolution of physical quantities in a singular theory. The origin of constraints is shown to be a consequence of the (unneeded in our formulation) extension of the phase space. In this case the new bracket transforms into the Dirac bracket. Quantization is briefly discussed.

  18. Feasibility of building robust surface electromyography-based hand gesture interfaces.

    PubMed

    Xiang, Chen; Lantz, Vuokko; Kong-Qiao, Wang; Zhang-Yan, Zhao; Xu, Zhang; Ji-Hai, Yang

    2009-01-01

    This study explored the feasibility of building robust surface electromyography (EMG)-based gesture interfaces starting from the definition of input command gestures. As a first step, an offline experimental scheme was carried out for extracting user-independent input command sets with high class separability, reliability and low individual variations from 23 classes of hand gestures. Then three types (same-user, multi-user and cross-user test) of online experiments were conducted to demonstrate the feasibility of building robust surface EMG-based interfaces with the hand gesture sets recommended by the offline experiments. The research results reported in this paper are useful for the development and popularization of surface EMG-based gesture interaction technology. PMID:19963552

  19. Development of a laser-scattering-based probe for on-line measurement of surface roughness.

    PubMed

    Wang, Shihua; Tian, Yunhui; Tay, Cho Jui; Quan, Chenggen

    2003-03-01

    The design and properties of an optical probe for on-line measurement of surface roughness are discussed. Based on light scattering, a probe that consists of a laser diode, a measuring lens, and a linear photodiode array was designed to detect surface roughness, in which the light scattered from a test surface at a relatively large scattering angle phi (=28 degrees) can be collected to enhance measuring range and repeatability. A coaxial design that incorporates a dual-laser probe and compressed air makes the proposed system insensitive to the position of the test surface and to surface conditions such as the presence of debris, vibration, and lubricants that result from machining. The results from measurements of several sets of specimens have demonstrated the feasibility of measuring surface roughness by using light scattering. On-line measurement on a diamond-turning lathe has shown that the proposed technique is stable and compact enough to be applicable to on-line measurement of surface roughness of an engineering surface. PMID:12638888

  20. Sea surface effects on sound scattering in the Persian Gulf region based on empirical relations

    NASA Astrophysics Data System (ADS)

    Ghadimi, Parviz; Bolghasi, Alireza; Feizi Chekab, Mohammad A.

    2015-06-01

    In this paper, sound scattering from the sea surface in the Persian Gulf region is investigated. Chapman-Harris and Ogden-Erskine empirical relations coupled with perturbation theory are implemented. Based on the Ogden and Erskine's experiments, sound scattering from the sea surface has three different regimes in which two mechanisms of surface roughness and subsurface bubble clouds are involved. Ogden-Erskine's scattering relation which consists of perturbation theory and Chapman-Harris's scattering terms are verified by the experimental data of Critical Sea Tests 7. Subsequently, wind speed in the Persian Gulf is provided based on three data bases of Arzanah station, ERA40, and PERGOS. Accordingly, surface scattering strength in the Persian Gulf region is calculated at different grazing angles, frequencies and provided wind speeds. Based on the resulted values of scattering strength, scattered intensity from the sea surface is also studied. These studies indicate that both scattering strength and scattered intensity generally increase as grazing angle, frequency and wind speed increase.

  1. Spectroscopic Investigation of Surface Dependent Acid-base Property of Ceria Nanoshapes

    SciTech Connect

    Wu, Zili [ORNL; Mann, Amanda K [ORNL; Li, Meijun [ORNL; Overbury, Steven {Steve} H [ORNL

    2015-01-01

    In addition to their well-known redox character, the acid-base property is another interesting aspect of ceria-based catalysts. Herein, the effect of surface structure on the acid-base property of ceria was studied in detail by utilizing ceria nanocrystals with different morphologies (cubes, octahedra and rods) that exhibit crystallographically well-defined surface facets. The nature, type, strength and amount of acid and base sites on these ceria nanoshapes were investigated via in situ IR spectroscopy combined with various probe molecules. Pyridine adsorption shows the presence of Lewis acid sites (Ce cations) on the ceria nanoshapes. These Lewis acid sites are relatively weak and similar in strength among the three nanoshapes according to the probing by both pyridine and acetonitrile. Both Br nsted (hydroxyl group) and Lewis (surface lattice oxygen) base sites are present on the ceria nanoshapes as probed by CO2 adsorption. CO2 and chloroform adsorption indicate that the strength and amount of the Lewis base sites are shape dependent: rods > cubes > octahedra. The weak and strong surface dependence of the acid and base sites, respectively, are a result of interplay between the surface structure dependent coordination unsaturation status of the Ce cations and O anions and the amount of defect sites on the three ceria nanoshapes. Furthermore, it was found that the nature of the acid-base sites of ceria can be impacted by impurities, such as Na and P residues that result from their use as structure-directing reagent in the hydrothermal synthesis of the ceria nanocrystals. This observation calls for precaution in interpreting the catalytic behavior of nanoshaped ceria where trace impurities may be present.

  2. Automated identification of exudates and optic disc based on inverse surface thresholding.

    PubMed

    Yazid, Haniza; Arof, Hamzah; Isa, Hazlita Mohd

    2012-06-01

    This paper presents a new approach to detect exudates and optic disc from color fundus images based on inverse surface thresholding. The strategy involves the applications of fuzzy c-means clustering, edge detection, otsu thresholding and inverse surface thresholding. The main advantage of the proposed approach is that it does not depend on manually selected parameters that are normally chosen to suit the tested databases. When applied to two sets of databases the proposed method outperforms a method based on watershed segmentation. PMID:21318328

  3. New trends in instrumental design for surface plasmon resonance-based biosensors

    PubMed Central

    Abbas, Abdennour; Linman, Matthew J.; Cheng, Quan

    2010-01-01

    Surface plasmon resonance (SPR)-based biosensing is one of the most advanced label free, real time detection technologies. Numerous research groups with divergent scientific backgrounds have investigated the application of SPR biosensors and studied the fundamental aspects of surface plasmon polaritons that led to new, related instrumentation. As a result, this field continues to be at the forefront of evolving sensing technology. This review emphasizes the new developments in the field of SPR-related instrumentation including optical platforms, chips design, nanoscale approach and new materials. The current tendencies in SPR-based biosensing are identified and the future direction of SPR biosensor technology is broadly discussed. PMID:20951566

  4. Dielectrophoresis-Based Discrimination of Bacteria at the Strain Level Based on Their Surface Properties

    E-print Network

    Willner, Dana

    Insulator-based dielectrophoresis can be used to manipulate biological particles, but has thus far found limited practical applications due to low sensitivity. We present linear sweep three-dimensional insulator-based ...

  5. Theoretical studies of the work functions of Pd-based bimetallic surfaces.

    PubMed

    Ding, Zhao-Bin; Wu, Feng; Wang, Yue-Chao; Jiang, Hong

    2015-06-01

    Work functions of Pd-based bimetallic surfaces, including mainly M/Pd(111), Pd/M, and Pd/M/Pd(111) (M = 4d transition metals, Cu, Au, and Pt), are studied using density functional theory. We find that the work function of these bimetallic surfaces is significantly different from that of parent metals. Careful analysis based on Bader charges and electron density difference indicates that the variation of the work function in bimetallic surfaces can be mainly attributed to two factors: (1) charge transfer between the two different metals as a result of their different intrinsic electronegativity, and (2) the charge redistribution induced by chemical bonding between the top two layers. The first factor can be related to the contact potential, i.e., the work function difference between two metals in direct contact, and the second factor can be well characterized by the change in the charge spilling out into vacuum. We also find that the variation in the work functions of Pd/M/Pd(111) surfaces correlates very well with the variation of the d-band center of the surface Pd atom. The findings in this work can be used to provide general guidelines to design new bimetallic surfaces with desired electronic properties. PMID:26049515

  6. Evaluating surface roughness of a polyamide denture base material in comparison with poly (methyl methacrylate).

    PubMed

    Abuzar, Menaka A; Bellur, Suman; Duong, Nancy; Kim, Billy B; Lu, Priscilla; Palfreyman, Nick; Surendran, Dharshan; Tran, Vinh T

    2010-12-01

    Polyamide denture base materials are more flexible than the commonly used poly (methyl methacrylate) (PMMA). However polishability of polyamides has not been examined adequately. This study investigated the surface roughness (Ra) and clinical acceptability of samples of a polyamide denture base material and PMMA fabricated by injection moulding and traditional heat processing systems, respectively. Half of each sample surface was polished using the conventional technique (lathe with pumice followed by high shine buffs) and the other half was left unpolished. A profilometer was used to measure Ra along 3 tracks on each surface before and after polishing. Two-way ANOVA was used to compare the two surfaces of the two materials for variations in Ra values. Polyamide denture base material when polished with conventional laboratory technique became more than 7 times smoother whereas processed PMMA when polished became more than 20 times smoother using the same polishing technique. However the surface roughness of polyamide is well within the accepted norm of 0.2 µm Ra. Polyamide produces a clinically acceptable smoothness after conventional polishing by lathe. PMID:21206160

  7. Enhancing model-based land surface temperature estimates using multiplatform microwave observations

    NASA Astrophysics Data System (ADS)

    Holmes, Thomas R. H.; Crow, Wade T.; Tugrul Yilmaz, M.; Jackson, Thomas J.; Basara, Jeffrey B.

    2013-01-01

    Land surface temperature plays an important role in surface processes and is a key input for physically based retrieval algorithms of soil moisture and evaporation. This study presents a framework for using independent estimates of land surface temperature from five microwave satellite sensors to improve the accuracy of land surface temperature output from a numerical weather prediction system in an off-line (postprocessing) analysis. First, structural differences in timing and amplitude of the temperature signal were addressed. Then, satellite observations were assimilated into an auto-regressive error model, formulated to estimate errors in the numerical weather prediction output. Errors in daily minimum and amplitude were treated separately. Results of this study provide new insights about potential added benefits of preprocessing and off-line assimilation of microwave remote sensing-based and model-based temperature retrievals. It is shown that the satellite observations may be used to reduce errors in surface temperature, particularly for day-time hours. Preprocessing is responsible for the bulk of this reduction in temperature error; data assimilation is shown to further reduce the random temperature error by a few tenths of a Kelvin, accounting for a 10% reduction in RMSE.

  8. Mutation Screening Based on the Mechanical Properties of DNA Molecules Tethered to a Solid Surface

    PubMed Central

    Yeri, Ashish S; Gao, Lizeng; Gao, Di

    2009-01-01

    We report a rapid gene mutation screening method by making use of the mechanical properties of single-strand DNA (ssDNA) tethered to a solid surface. With proper temperature control, ssDNA in solution undergoes intra-base pairing and forms a specific complex 3D structure. By tethering such ssDNA strands to a solid surface, a DNA film can be formed. The mechanical properties of such DNA films, probed by devices such as a quartz crystal resonator, are directly related to the specific structure of the ssDNA which is characteristic of its base sequence, and thus can be used as the basis for mutation screening. Using this approach, we have detected a single base mutation among 545 bases in P53 gene. This result suggests promising potential of employing the mechanical properties of DNA strands for rapid screening of mutations. PMID:20030306

  9. Optimization of Cutting Parameters Based on Surface Roughness and Assistance of Workpiece Surface Temperature in Turning Process

    Microsoft Academic Search

    Adeel H. Suhail; N. Ismail; S. V. Wong; N. A. Abdul

    2010-01-01

    Problem statement: In machining operation, the quality of surface fini sh is an important requirement for many turned workpieces. Thus, the c hoice of optimized cutting parameters is very important for controlling the required surface qual ity. Approach: The focus of present experimental study is to optimize the cutting parameters using t wo performance measures, workpiece surface temperature and surface

  10. Regional mean sea surfaces based on GEOS-3 and SEASAT altimeter data

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Cheney, R. E.; Mccarthy, J. J.; Martin, T. V.

    1984-01-01

    Altimetric sea surfaces provide a basis for detailed analyses of the earth's gravity, crustal structure, and the oceanic surface circulation. Long-term mean surfaces have been computed for the Bering Sea, Northwest Atlantic Ocean, and Gulf of Mexico based on a combination of the entire SEASAT (three-month) and GEOS-3 (3.5-year) altimeter data sets. The number of available passes ranged from 558 in the gulf to 1396 in the Atlantic. The large amount of data in these areas, coupled with the incresed constraint provided by the combination of data from two orbital inclinations, has permited the accurate removal of the effects of radial ephemeris error through crossing arc adjustments. The precision of these regional mean sea surfaces is approximately 15 cm, with horizontal resolutions approaching 25 km.

  11. Simultaneous Sterilization With Surface Modification Of Plastic Bottle By Plasma-Based Ion Implantation

    SciTech Connect

    Sakudo, N.; Ikenaga, N.; Ikeda, F.; Nakayama, Y.; Kishi, Y.; Yajima, Z. [Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838 (Japan)

    2011-01-07

    Dry sterilization of polymeric material is developed. The technique utilizes the plasma-based ion implantation which is same as for surface modification of polymers. Experimental data for sterilization are obtained by using spores of Bacillus subtilis as samples. On the other hand we previously showed that the surface modification enhanced the gas barrier characteristics of plastic bottles. Comparing the implantation conditions for the sterilization experiment with those for the surface modification, we find that both sterilization and surface modification are simultaneously performed in a certain range of implantation conditions. This implies that the present bottling system for plastic vessels will be simplified and streamlined by excluding the toxic peroxide water that has been used in the traditional sterilization processes.

  12. Asteroseismic-based Estimation of the Surface Gravity for the LAMOST Giant Stars

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Fang, Min; Wu, Yue; Deng, Li-Cai; Wang, Liang; Wang, Wei; Fu, Jian-Ning; Hou, Yong-Hui; Li, Guang-Wei; Zhang, Yong

    2015-07-01

    Asteroseismology is one of the most accurate approaches to estimate the surface gravity of a star. However, most of the data from the current spectroscopic surveys do not have asteroseismic measurements, which is very expensive and time consuming. In order to improve the spectroscopic surface gravity estimates for a large amount of survey data with the help of the small subset of the data with seismic measurements, we set up a support vector regression (SVR) model for the estimation of the surface gravity supervised by 1374 Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) giant stars with Kepler seismic surface gravity. The new approach can reduce the uncertainty of the estimates down to about 0.1 dex, which is better than the LAMOST pipeline by at least a factor of 2, for the spectra with signal-to-noise ratio higher than 20. Compared with the log g estimated from the LAMOST pipeline, the revised log g values provide a significantly improved match to the expected distribution of red clump and red giant branch stars from stellar isochrones. Moreover, even the red bump stars, which extend to only about 0.1 dex in log g, can be discriminated from the new estimated surface gravity. The method is then applied to about 350,000 LAMOST metal-rich giant stars to provide improved surface gravity estimates. In general, the uncertainty of the distance estimate based on the SVR surface gravity can be reduced to about 12% for the LAMOST data.

  13. Facile hydrophobicity/hydrophilicity modification of SMP surface based on metal constrained cracking

    NASA Astrophysics Data System (ADS)

    Han, Yu; Li, Peng; Zhao, Liangyu; Wang, Wenxin; Leng, Jinsong; Jin, Peng

    2015-04-01

    This study demonstrates an easy way to change surface characteristics, the water contact angle on styrene based shape memory polymer (SMP) surface alters before and after cracking formation and recovery. The contact angle of water on the original SMP surface is about 85 degree, after coating with Al and then kneading from side face at glass transition temperature Tg, cracking appeared both on Al film and SMP; cooling down and removing the Al film, cracks remain on SMP surface while the contact angle reduced to about 25 degree. When reheated above Tg, the cracks disappeared, and the contact angle go back to about 85 degree. The thin Al film bonded on SMP surface was coated by spurting, that constrains the deformation of SMP. Heating above Tg, there are complex interactions between soft SMP and hard metal film under kneading. The thin metal film cracked first with the considerable deformation of soft polymer, whereafter, the polymer was ripped by the metal cracks thus polymer cracked as well. Cracks on SMP can be fixed cooling down Tg, while reheated, cracks shrinking and the SMP recovers to its original smooth surface. Surface topography changed dramatically while chemical composition showed no change during the deformation and recovery cycle, as presented by SEM and EDS. Furthermore, the wetting cycle is repeatable. This facile method can be easily extended to the hydropobicity/hydrophilicity modification of other stimuli-responsive polymers and put forward many potential applications, such as microfluidic switching and molecule capture and release.

  14. Medium PRF Waveforms: an optimal solution for various applications in surface based radar

    Microsoft Academic Search

    Peter N. C. Nooy; Jean-Claude Debuisser

    1998-01-01

    In this paper the Pulse Repetition Frequency (PRF)-induced targetfold back dilemma in the range-velocity domain of the Pulsed Doppler (PD)-radar is addressed for `surface based' applications, i.e. naval or ground based radar. The terms low-, medium- and high-PRF radar are related to the Radar carrier Frequency (RF)-dependent clutter pollution ratio in the unambiguous fundamental velocity or Doppler domain. It is

  15. Study of cutting speed on surface roughness and chip formation when machining nickel-based alloy

    Microsoft Academic Search

    Basim A. Khidhir; Bashir Mohamed

    2010-01-01

    Nickel-based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature.\\u000a The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts\\u000a under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects\\u000a of cutting speed on surface

  16. Surface changes induced by fluoride prophylactic agents on titanium-based orthodontic wires

    Microsoft Academic Search

    Ikuya Watanabe; Etsuko Watanabe

    2003-01-01

    This study investigated the effect of fluoride prophylactic agents on the surfaces of titanium-based orthodontic wires. Four types of titanium-based orthodontic wires (2 nickel-titanium alloy wires [nickel-titanium and copper-nickel-titanium] and 2 ?-titanium alloy wires [titanium-molybdenum and titanium-niobium], all from Ormco, Glendora, Calif) with similar sizes were prepared and immersed in 5 fluoride prophylactic agents (2 acidulated phosphate fluoride agents [Nupro

  17. Estimation of surface longwave radiation components from ground-based historical net radiation and weather data

    Microsoft Academic Search

    Gi-Hyeon Park; Xiaogang Gao; Soroosh Sorooshian

    2008-01-01

    A methodology for estimating ground upwelling, clear-sky and cloud downwelling longwave radiations (L?, Lsky?, and Lcld?) and net shortwave radiation (Sn) at 30-min temporal scales based on long-term ground-based net radiations and meteorological observations is described. Components of surface radiation can be estimated from empirical models, cloud radiation models, and remote sensing observations. The proposed method combines the local calibration

  18. Novel failure modes with overmolded printed circuit board-based surface mount packages

    Microsoft Academic Search

    Joseph M. Duffalo; David L. Erhart; Shari C. Schmok

    1993-01-01

    Several failure modes observed during reliability stress testing of a new generation of printed-circuit-board-based surface mounted packages are discussed. When compared with conventional plastic quad flat pack packages these failure modes are shown to be a direct result of the introduction of new material interfaces, and thermal expansion mismatches. If the PCB-based packages are compared to conventional plastic quad flat

  19. Electromagnetic probing for target detection: rejection of surface clutter based on the Wigner distribution.

    PubMed

    Morelle, Nicolas; Testorf, Markus E; Thirion, Nadège; Saillard, Marc

    2009-05-01

    The Wigner distribution function is investigated as a signal processing tool to detect subsurface targets closely located beneath a randomly rough surface. Information provided by a bistatic arrangement of sources and detectors can be used to discriminate target and surface response based on their scattering behavior. It is shown that the bilinearity of the Wigner distribution function can be exploited for nonlinear amplification of the target response. This is achieved by averaging the Wigner distribution of the detected signal for different source locations. Target detection is further improved by numerically backpropagating the detected signal to the surface. A statistical evaluation based on simulated data sets is used to evaluate the performance of the detection method. PMID:19412235

  20. New model for the correlation of the surface tension based on friction theory.

    PubMed

    Quiñones-Cisneros, S E; Deiters, U K; Rozas, R E; Kraska, T

    2009-03-19

    A new correlation method for the surface tension of fluids is proposed, which is based on friction theory applied to the interface of a two-phase system. The substance properties enter the model by a regular equation of state. Here we derive the method and test it with the Lennard-Jones 12-6 fluid as the reference system using molecular dynamics simulations of the vapor-liquid interface in combination with a new Lennard-Jones 12-6 equation of state. Further correlations of experimental surface tension data based on the Peng-Robinson and the PC-SAFT equations of state are presented. As a result, we find that the method allows an accurate correlation of the surface tension of pure fluids. PMID:19236013