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1

The effects of primer precuring on the shear bond strength between gold alloy surfaces and metal brackets.  

PubMed

The objective of this study was to investigate the effects of precuring of primer coated on bracket bases on the strength of bonds between metal brackets and gold alloy. Square type III gold alloy plates were sandblasted with 30 ?m silicon dioxide. After silica coating, excessive particles were removed gently with air. Silane was then applied, and maxillary central incisor metal brackets were bonded to each conditioned alloy surface with Transbond XT. Half of the specimens were precured at the bracket base after primer coating and the other half was not precured before bonding to the alloy surface. After bracket positioning, samples were cured using a light emitting diode (LED) for 40 seconds. Shear bond strengths were tested and adhesive remnant index (ARI) was evaluated after 1 hour and 24 hours. The primer precuring and 24 hours group exhibited highest bond strength (12.53 MPa) and the no precuring and 1 hour group showed lowest bond strength (5.58 MPa). Precured groups showed lower ARI scores. Due to the shallow curing depth of LED light and inhibition of transillumination at the metal surface, primer precuring at the bracket base is required for secure bracket bonding on gold alloy surfaces using LED curing units. PMID:21118910

Shon, Won-Jun; Kim, Tae-Woo; Chung, Shin-Hye; Jung, Min-Ho

2012-02-01

2

Changes in the surface roughness and friction coefficient of orthodontic bracket slots before and after treatment.  

PubMed

In this study, we tested the surface roughness of bracket slots and the friction coefficient between the bracket and the stainless steel archwire before and after orthodontic treatment. There were four experimental groups: groups 1 and 2 were 3M new and retrieved brackets, respectively, and groups 3 and 4 were BioQuick new and retrieved brackets, respectively. All retrieved brackets were taken from patients with the first premolar extraction and using sliding mechanics to close the extraction space. The surface roughness of specimens was evaluated using an optical interferometry profilometer, which is faster and nondestructive compared with a stylus profilometer, and provided a larger field, needing no sample preparation, compared with atomic force microscopy. Orthodontic treatment resulted in significant increases in surface roughness and coefficient of friction for both brands of brackets. However, there was no significant difference by brand for new or retrieved brackets. These retrieval analysis results highlight the necessity of reevaluating the properties and clinical behavior of brackets during treatment to make appropriate treatment decisions. PMID:23086715

Liu, Xiaomo; Lin, Jiuxiang; Ding, Peng

2013-01-01

3

The Influence of No-Primer Adhesives and Anchor Pylons Bracket Bases on Shear Bond Strength of Orthodontic Brackets  

PubMed Central

Objective. The aim of this study was to compare the shear bond strength (SBS) and adhesive remnant index (ARI) scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP) with different bracket bases (anchor pylons and 80-gauge mesh) were bonded to the teeth using a conventional adhesive (Transbond XT) and two different no-primer adhesive (Ortho Cem; Heliosit) systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs), Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs. PMID:23984339

Sfondrini, Maria Francesca; Fraticelli, Danilo; Daina, Paola; Tamagnone, Alessandra; Gandini, Paola

2013-01-01

4

Influence of surface treatments on the shear bond strength of orthodontic brackets to porcelain  

NASA Astrophysics Data System (ADS)

The purpose of this study was to investigate the effect of various surface treatments after different storage time and thermocycling on the shear bond strength of orthodontic brackets to the feldspathic porcelain surfaces. 128 disc-shaped porcelain specimens were randomly assigned to the following surface treatments: 9.6% HFA, 9.6% HFA combined with silane, 50 ? aluminum trioxide sandblasting followed by silane and application of silane after 37% phosphoric acid. Metal or ceramic brackets were bonded onto each treated porcelain facet with light cured resin. The samples were stored in 37 °C water 1 day or 7 days, thermocycled 500 times from 5 to 55 °C. The shear bond strengths were measured (1 mm/min), and statistically analyzed. The bond failure sites were classified according to ARI system. The surface of the glazed, sandblasted, hydrofluoric and phosphoric acid etched porcelain were examined with SEM. All groups achieved reasonable bond strengths to withstand the application of orthodontic forces. Water storage for 7 days caused lower shear bond strength than that of 1 day. But there is no statistically significant difference between the two groups. The mean shear bond strength provided by ceramic bracket with mechanical retention had no statistical difference with that of metal bracket. Therefore, the optimal treatment for orthodontic brackets bonding to feldspathic porcelain was to apply phosphoric acid combined with silane.

Wang, Cong; Zeng, Jishan; Wang, Shaoan; Yang, Zheng; Huang, Qian; Chen, Pixiu; Zhou, Shujuan; Liu, Xiaoqing

2008-11-01

5

Effects of silanation time on shear bond strength between a gold alloy surface and metal bracket  

PubMed Central

Objective We aimed to investigate the effects of silanation time on the shear bond strength (SBS) of metal brackets on gold alloy in a silicoating procedure and compare the SBS of metal brackets on gold alloy and enamel. Methods Type III gold alloy plates were sandblasted with 30-µm silicon dioxide. Excess particles were removed with gentle air after silica coating, and silane was applied. Maxillary central-incisor metal brackets were bonded to each conditioned alloy surface with a light curing resin adhesive for 1 s, 30 s, 60 s, or 120 s after applying silane. The brackets were also bonded to 36 upper central incisors with the same adhesive. All samples were cured for 40 s with a light emitting diode curing light. The SBS was tested after 1 h and after 24 h. The adhesive remnant index (ARI) of the samples was also compared. Results The 60-s and 120-s silanation time groups showed a higher SBS than the other groups (p < 0.05). Samples tested after 24 h showed a significantly higher SBS than did the samples tested after 1 h (p < 0.05). The 1-s group showed higher ARI scores. The one-way analysis of variance and Student-Newman-Keuls test showed that the SBS values of the 60-s and 120-s silanation time groups were not significantly different from the SBS values of enamel. Conclusions Adequate silanation time is required to produce sufficient bond strength during silicoating. PMID:23814707

Shon, Won-Jun; Park, Young-Seok; Chung, Shin-Hye

2013-01-01

6

Effects of silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets  

PubMed Central

Objective The aim of this study was to evaluate the effects of tribochemical silica coating and silane surface conditioning on the bond strength of rebonded metal and ceramic brackets. Material and Methods Twenty debonded metal and 20 debonded ceramic brackets were randomly assigned to receive one of the following surface treatments (n=10 for each group): (1) sandblasting (control); (2) tribochemical silica coating combined with silane. Brackets were rebonded to the enamel surface on the labial and lingual sides of premolars with a light-polymerized resin composite. All specimens were stored in distilled water for 1 week and then thermocycled (5,000 cycles) between 5-55°C. Shear bond strength values were measured using a universal testing machine. Student's t-test was used to compare the data (?=0.05). Failure mode was assessed using a stereomicroscope, and the treated and non-treated bracket surfaces were observed by scanning electron microscopy. Results Rebonded ceramic brackets treated with silica coating followed by silanization had significantly greater bond strength values (17.7±4.4 MPa) than the sandblasting group (2.4±0.8 MPa, P<0.001). No significant difference was observed between the rebonded metal brackets treated with silica coating with silanization (15±3.9 MPa) and the sandblasted brackets (13.6±3.9 MPa). Treated rebonded ceramic specimens primarily exhibited cohesive failure in resin and adhesive failure at the enamel-adhesive interface. Conclusions In comparison to sandblasting, silica coating with aluminum trioxide particles followed by silanization resulted in higher bond strengths of rebonded ceramic brackets. PMID:21625739

ATSÜ, Saadet; ÇATALBA?, Bülent; GELGÖR, ?brahim Erhan

2011-01-01

7

Surface morphology and electrical properties of Au/Ni/ Left-Pointing-Angle-Bracket C Right-Pointing-Angle-Bracket /n-Ga{sub 2}O{sub 3}/p-GaSe Left-Pointing-Angle-Bracket KNO{sub 3} Right-Pointing-Angle-Bracket hybrid structures fabricated on the basis of a layered semiconductor with nanoscale ferroelectric inclusions  

SciTech Connect

Features of the formation of Au/Ni/ Left-Pointing-Angle-Bracket C Right-Pointing-Angle-Bracket /n-Ga{sub 2}O{sub 3} hybrid nanostructures on a Van der Waals surface (0001) of 'layered semiconductor-ferroelectric' composite nanostructures (p-GaSe Left-Pointing-Angle-Bracket KNO{sub 3} Right-Pointing-Angle-Bracket ) are studied using atomic-force microscopy. The room-temperature current-voltage characteristics and the dependence of the impedance spectrum of hybrid structures on a bias voltage are studied. The current-voltage characteristic includes a resonance peak and a portion with negative differential resistance. The current attains a maximum at a certain bias voltage, when electric polarization switching in nanoscale three-dimensional inclusions in the layered GaSe matrix occurs. In the high-frequency region (f > 10{sup 6} Hz), inductive-type impedance (a large negative capacitance of structures, {approx}10{sup 6} F/mm{sup 2}) is detected. This effect is due to spinpolarized electron transport in a series of interconnected semiconductor composite nanostructures with multiple p-GaSe Left-Pointing-Angle-Bracket KNO{sub 3} Right-Pointing-Angle-Bracket quantum wells and a forward-biased 'ferromagnetic metal-semiconductor' polarizer (Au/Ni/ Left-Pointing-Angle-Bracket C Right-Pointing-Angle-Bracket /n{sup +}-Ga{sub 2}O{sub 3}/n-Ga{sub 2}O{sub 3}). A shift of the maximum (current hysteresis) is detected in the current-voltage characteristics for various directions of the variations in bias voltage.

Bakhtinov, A. P., E-mail: chimsp@ukrpost.ua; Vodopyanov, V. N.; Netyaga, V. V.; Kudrynskyi, Z. R. [National Academy of Sciences of Ukraine, Frantsevich Institute for Problems of Materials Science, Chernivtsi Branch (Ukraine); Lytvyn, O. S. [National Academy of Sciences, Lashkaryov Institute of Semiconductor Physics (Ukraine)

2012-03-15

8

Enamel Surface Roughness after Debonding of Orthodontic Brackets and Various Clean-Up Techniques  

PubMed Central

Objective: This study aimed to evaluate enamel roughness after adhesive removal using different burs and an Er:YAG laser. Materials and Methods: The buccal surfaces of forty human premolars were sealed by two layers of nail varnish, except for a circular area of 3 mm in diameter on the middle third. The enamel surfaces were initially subjected to profilometry analysis and four parameters of surface irregularity (Ra, Rq, Rt and Rz) were recorded. Following bracket bonding and debonding, adhesive remnants were removed by tungsten carbide burs in low- or high- speed handpieces (group 1 and 2, respectively), an ultrafine diamond bur (group 3) or an Er:YAG laser (250 mJ, long pulse, 4 Hz) (group 4), and surface roughness parameters were measured again. Then, the buccal surfaces were polished and the third profilometry measurements were performed. Results: The specimens that were cleaned with a low speed tungsten carbide bur showed no significant difference in surface irregularity between the different treatment stages (p>0.05). Surface roughness increased significantly after clean-up with the diamond bur and the Er:YAG laser (p<0.01). In comparison between groups, adhesive removal with tungsten carbide burs at slow- or high-speed handpieces produced the lowest, while enamel clean-up with the Er:YAG laser caused the highest values of roughness measurements (P<0.05). Conclusion: Under the study conditions, application of the ultrafine diamond bur or the Er:YAG laser caused irreversible enamel damage on tooth surface, and thus these methods could not be recommended for removing adhesive remnants after debonding of orthodontic brackets. PMID:23724206

Ahrari, Farzaneh; Akbari, Majid; Akbari, Javad; Dabiri, Ghahraman

2013-01-01

9

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

PubMed Central

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

2013-01-01

10

The Effects of In-office Reconditioning on the Morphology of Slots and Bases of Stainless Steel Brackets and on the Shear\\/Peel Bond Strength  

Microsoft Academic Search

Objectives: To compare the effect of five in-office bracket reconditioning methods on: (i) bracket slot width and inter- wing gap measurements; (ii) the appearance of the bracket bases under scanning electron microscope (SEM), and; (iii) shear\\/peel bond strength (SPBS). Setting: Ex vivo study. Method: One hundred and twenty-five brackets were initially bonded and were divided into five experimental groups and

AISHA M. BASUDAN; SULIMAN E. AL

2001-01-01

11

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

PubMed Central

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

Shahabi, Mostafa; Mohamadipour, Hamideh; Moosavi, Horieh

2014-01-01

12

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

PubMed Central

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

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

2013-01-01

13

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

PubMed Central

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

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

2012-01-01

14

Universal Cable Brackets  

NASA Technical Reports Server (NTRS)

Concept allows routing easily changed. No custom hardware required in concept. Instead, standard brackets cut to length and installed at selected locations along cable route. If cable route is changed, brackets simply moved to new locations. Concept for "universal" cable brackets make it easy to route electrical cable around and through virtually any structure.

Vanvalkenburgh, C.

1985-01-01

15

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

PubMed Central

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

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

2014-01-01

16

Electrical Servo Actuator Bracket.  

National Technical Information Service (NTIS)

A bracket for an electrical servo actuator is disclosed which was developed particularly for jet engine fuel control values. Said servo actuator is mounted on a support arm which is allowed to pivot on a bolt through a fixed mounting bracket. The actuator...

R. V. Sawyer

1980-01-01

17

Longitudinal epiphyseal bracket.  

PubMed

A longitudinal epiphyseal bracket (LEB) is a defect of the tubular bones and has been primarily described in the hands and feet, especially the proximal phalanges, metacarpals, and metatarsals. The LEB results from a defective C-shaped secondary ossification center that brackets the diaphysis and metaphysis, causing restricted longitudinal growth in these bones with resultant shortening and angular deformities. Deformities associated with metatarsal epiphyseal bracket include a short, broad metatarsal and medial deviation of the metatarsophalangeal joint (hallux varus deformity). Excision of the cartilaginous LEB has been proposed to prevent future soft tissue contractures and osseous deformities. The LEB has been associated with numerous syndromes including Rubinstein-Taybi syndrome, Cenani-Lenz syndactyly, isolated oligosyndactyly, and Nievergelt syndrome. We describe a two-month-old patient in whom plain film and MR imaging demonstrated bilateral bracketed first metatarsals with associated hallux varus deformities. Bilateral bracket excision was performed with excellent clinical results. PMID:18085094

Nguyen, Jimmy Q; Gatewood, Jason B; Beall, Douglas; Herndon, William; Puffinberger, William R; Ly, Justin; Fish, Jon R

2007-10-01

18

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

PubMed Central

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

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

2014-01-01

19

Effects of recycling and bonding agent application on bond strength of stainless steel orthodontic brackets  

PubMed Central

Objectives: 1) to assess different methods of recycling orthodontic brackets, 2) to evaluate Shear Bond Strength (SBS) of (a) new, (b) recycled and (c) repeated recycled stainless steel brackets (i) with and (ii) without bracket base primer. Study Design: A total of 180 extracted human premolar teeth and 180 premolar stainless steel brackets were used. One hundred teeth and 100 brackets were divided into five groups of 20-teeth each. Four methods of recycling orthodontic brackets were used in each of the first four groups while the last one (group V) was used as the control. Groups (I-V) were subjected to shear force within half an hour until the brackets debond. SBS was measured and the method showing the highest SBS was selected. A New group (VI) was recycled twice with the selected method. Six subgroups (1-6) were established; the primer was applied for three sub-groups, and the composite was applied for all brackets. Brackets were subjected to the same shear force, and SBS was measured for all sub-groups. Results: There was a significant difference between the mean SBS of the sandblasting method and the means of SBS of each of the other three methods. There was however, no significant difference between the mean SBS of the new bracket and the mean SBS of recycled bracket using sandblasting. The mean SBS of all sub-groups were more than that recommended by Reynolds (17) in 1975. Brackets with primer showed slightly higher SBS compared to those of brackets without bonding agent. Conclusion: To decrease cost, sandblasted recycled orthodontic brackets can be used as an alternative to new brackets. It is recommended to apply a bonding agent on the bracket base to provide greater bond strength. Key words:Recycled bracket, shear bond strength, sandblasting, stainless steel orthodontic bracket. PMID:24455081

Bahnasi, Faisal I.; Abu-Hassan, Mohame I.

2013-01-01

20

Bond strengths evaluation of laser ceramic bracket debonding  

NASA Astrophysics Data System (ADS)

Ceramic brackets often used for an orthodontic treatment can lead to problems such as enamel tear outs because of their low fracture resistance and high bond strengths. Therefore the aim of our study was to investigate the positive laser radiation effect on bracket debonding. Moreover, the influence of the enamel shape surface under the bracket and laser radiation power on the debonding strength was investigated. The source of the radiation was the longitudinally diode-pumped Tm:YAP laser operating at 1997 nm. To eliminate the tooth surface roughness the flat enamel surface was prepared artificially and the bracket was bonded on it. The debonding was accomplished by Tm:YAP laser radiation with different the power value while recording the temperature rise in the pulp. To simulate the debonding process in vivo the actual bond strength was measured by the digital force gauge. The results were analyzed by scanning electron microscope.

Dostalová, T.; Jelinková, H.; Šulc, J.; N?mec, M.; Fibrich, M.; Jelínek, M.; Michalík, P.; Bu?ková, M.

2012-09-01

21

Reconditioning of ceramic orthodontic brackets with an Er,Cr:YSGG laser.  

PubMed

It is now known that erbium lasers are effective in composite removal, but there is minimal information about their efficacy on recycling of ceramic brackets. This study, therefore, aimed to determine the percentage of remaining adhesive on the base and the shear bond strength of debonded ceramic brackets after being reconditioned by an Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) laser. Thirty premolars were divided into three groups, then bonded with mechanical retention ceramic brackets according to the bracket base conditions: (1) new brackets; (2) debonded brackets cleaned of adhesive with the Er,Cr:YSGG laser at 3.5 W; and (3) debonded brackets cleaned of adhesive with the Er,Cr:YSGG laser at 4 W. Before bonding, the percentage of remaining adhesive on the bases of reconditioned brackets was calculated by using stereomicroscopic images through an image processing software. The brackets were then tested in shear mode in a universal testing machine and the adhesive remnant index scores were determined. The percentage of remaining adhesive on the bases of brackets that were cleaned by the Er,Cr:YSGG laser at 4 W (3.1 %) was significantly lower than that of the 3.5-W laser group (5.9 %) (p = 0.03). No significant difference was found in bond strengths between the new and the reconditioned brackets (p = 0.19). The frequency of bond failure at the enamel-adhesive interface was lower in the laser-reconditioned brackets when compared to the new brackets. The application of Er,Cr:YSGG laser was efficient in removing adhesive from bases of debonded ceramic brackets because it produced comparable bond strengths to new brackets while reducing the risk of enamel damage during debonding. PMID:22585379

Ahrari, Farzaneh; Fekrazad, Reza; Kalhori, Katayoun A M; Ramtin, Mahshid

2013-01-01

22

Friction between different wire bracket combinations in artificial saliva – an in vitro evaluation  

PubMed Central

Objective The objective this work was to assess the friction coefficient between brackets and wires of different materials under conditions simulating the oral environment. Material and Methods Stainless steel (SS) and titanium-molybdenum alloy (TMA) wires of 0.019x0.025-in diameter (American Orthodontics) and polycarbonate bracket (American Orthodontics), ceramic bracket (American Orthodontics), and metal bracket (3M Unitek) with slots of 0.022x0.030-in were used. The friction coefficient was assessed by means of mechanical traction with the system immersed in artificial saliva. The mean roughness of both wire surface and bracket slots was evaluated by using a surface profilometer. Results The system using TMA wire and polycarbonate bracket had the highest roughness (p<0.05). SS wire with ceramic bracket had the highest friction coefficient, whereas the use of metallic bracket yielded the lowest (p<0.05). However, it was observed a statistically significant difference in the system using TMA wire and ceramic bracket compared to that using TMA wire and polycarbonate bracket (p=0.038). Conclusion Ceramic brackets in association with SS wire should be judiciously used, since this system showed a high friction coefficient. PMID:21437471

FIDALGO, Tatiana Kelly da Silva; PITHON, Matheus Melo; MACIEL, José Vinicius Bolognesi; BOLOGNESE, Ana Maria

2011-01-01

23

Prevention of demineralization around orthodontic brackets using two different fluoride varnishes  

PubMed Central

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

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

2013-01-01

24

Bond strengths of ceramic brackets using different bonding techniques.  

PubMed

A series of laboratory investigations was carried out to compare the shear-type bond strengths and site of bond failure of ceramic orthodontic brackets bonded to etched enamel. When light-cured composite resin was used as the luting agent, there was no reduction in bond strength when using 2.5 per cent nitric acid to etch the enamel, compared to 37 per cent phosphoric acid. The use of the two resin modified glass ionomer cements were found to give rise to significantly lower bond strengths than composite resin when used for placing ceramic brackets. Significantly less composite resin remained on the enamel surface following bracket removal in those samples etched with nitric acid. PMID:7786864

Blight, S J; Lynch, E

1995-02-01

25

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

PubMed Central

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

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

2014-01-01

26

Effect of fluoride on friction between bracket and wire  

PubMed Central

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

Alavi, Shiva; Farahi, Ali

2011-01-01

27

Longer treatment times with self-ligated orthodontic brackets.  

PubMed

Data sourcesThe Medline, Cochrane Library, Biomed Central, BBO including LILACS, Ind Med, Sceilo, Clinical trials.gov, Conference paper Index, Digital Dissertations, German National Library of Medicine (ZB MED), Google Scholar, ISI Web of Knowledge, metaRegister of Controlled Trials, OpenSIGLE and Scirus databases were searched.Study selectionRandomised controlled trials (RCTs) and quasi-RCTs in patients having fixed-appliance orthodontic treatments were considered.Data extraction and synthesisStudy assessment data extraction and risk of bias assessment was carried out independently by two reviewers. Overall quality of evidence was based on the Grades of Recommendation Assessment, Development and Evaluation (GRADE) approach. Random-effects meta-analyses were performed where data could be pooled.ResultsTwenty five trials (1321 patients) were included. The majority (24) compared self-ligated (SL) and conventional brackets (CL). No trials primarily investigated the effect of bracket material and no indirect comparison was possible. Two trials assessed the bracket slot size but found no consistent difference between 0.022'' and 0.018'' brackets. Four studies contributed to a meta-analysis that showed overall duration of the orthodontic treatment be significantly longer in the SL group by 2.01 months (95%CI; 0.45 to 3.57).ConclusionsBased on existing evidence, no clinical recommendation can be made regarding the bracket material or different ligation modules. For Sl brackets, no conclusive benefits could be proven, while their use was associated with longer treatment durations. PMID:25343400

O'Brien, Kevin

2014-09-01

28

Three-dimensional deformation of orthodontic brackets  

PubMed Central

Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201

Melenka, Garrett W; Nobes, David S; Major, Paul W

2013-01-01

29

Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations  

PubMed Central

Objective To compare the influence of archwire material (NiTi, beta-Ti and stainless steel) and brackets design (self-ligating and conventional) on the frictional force resistance. Material and Methods Two types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and conventional brackets - Gemini, 3M/Unitek) with three (0, 5, and 10 degrees) slot angulation attached with elastomeric ligatures (TP Orthodontics) were tested. All brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium, and stainless steel (Unitek/3M). The mechanical testing was performed with a universal testing machine eMIC DL 10000 (eMIC Co, Brazil). The wires were pulled from the bracket slots at a cross-head speed of 3 mm/min until 2 mm displacement. Results Self-ligating brackets produced significantly lower friction values compared with those of conventional brackets. Frictional force resistance values were directly proportional to the increase in the bracket/ wire angulation. With regard to conventional brackets, stainless steel wires had the lowest friction force values, followed by nickel-titanium and beta-titanium ones. With regard to self-ligating brackets, the nickel-titanium wires had the lowest friction values, significantly lower than those of other materials. Conclusion even at different angulations, the self-ligating brackets showed significantly lower friction force values than the conventional brackets. Combined with nickel-titanium wires, the self-ligating brackets exhibit much lower friction, possibly due to the contact between nickel-titanium clips and wires of the same material. PMID:25025564

MONTEIRO, Maria Regina Guerra; da SILVA, Licinio Esmeraldo; ELIAS, Carlos Nelson; VILELLA, Oswaldo de Vasconcellos

2014-01-01

30

Galvanic corrosion between orthodontic wires and brackets in fluoride mouthwashes.  

PubMed

The aim of this investigation was to determine the influence of fluoride in certain mouthwashes on the risk of corrosion through galvanic coupling of orthodontic wires and brackets. Two titanium alloy wires, nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi), and the three most commonly used brackets, titanium (Ti), iron-chromium-nickel (FeCrNi) and cobalt-chromium (CoCr), were tested in a reference solution of Fusayama-Meyer artificial saliva and in two commercially available fluoride (250 ppm) mouthwashes, Elmex and Meridol. Corrosion resistance was assessed by inductively coupled plasma-atomic emission spectrometry (ICP-MS), analysis of released metal ions, and a scanning electron microscope (SEM) study of the metal surfaces after immersion of different wire-bracket pairs in the test solutions. The study was completed by an electrochemical analysis. Meridol mouthwash, which contains stannous fluoride, was the solution in which the NiTi wires coupled with the different brackets showed the highest corrosion risk, while in Elmex mouthwash, which contains sodium fluoride, the CuNiTi wires presented the highest corrosion risk. Such corrosion has two consequences: deterioration in mechanical performance of the wire-bracket system, which would negatively affect the final aesthetic result, and the risk of local allergic reactions caused by released Ni ions. The results suggest that mouthwashes should be prescribed according to the orthodontic materials used. A new type of mouthwash for use during orthodontic therapy could be an interesting development in this field. PMID:16428255

Schiff, Nicolas; Boinet, Mickaël; Morgon, Laurent; Lissac, Michèle; Dalard, Francis; Grosgogeat, Brigitte

2006-06-01

31

Bracket study : textual, computational, and digital  

E-print Network

Bracket system is an important and characteristic component in the traditional Chinese architecture. Much has been studied about the system - its origin, historical evolution, structure, and composition - in the traditional ...

Wu, Qiong, 1972-

2003-01-01

32

Sample-Based Surface Coloring  

PubMed Central

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

Burger, Kai; Kruger, Jens; Westermann, Rudiger

2011-01-01

33

Deformation of metal brackets: a comparative study.  

PubMed

The purpose of this study was to determine the effect of material and design on the force and stress required to permanently deform metal brackets. Fourteen types of metal brackets were categorized according to raw material composition, slot torque degree, and wing type. Five types of raw materials, three types of slot torque degree, and four types of wing design were tested using an archwire torque test developed by Flores. An analysis of variance (ANOVA) and t-test showed that all three categories had a significant effect on the force and stress needed to permanently deform metal brackets. Of the three, raw material had the greatest effect on the amount of force. Results showed that 17-4PH and 303S had higher yield strengths and regular twin brackets had higher resistance to deformation. Also, as slot torque degree increased, brackets deformed with less force. Result confirmed that brackets requiring the greatest stress to permanently deform were made of steel with the greatest hardness. PMID:7978523

Flores, D A; Choi, L K; Caruso, J M; Tomlinson, J L; Scott, G E; Jeiroudi, M T

1994-01-01

34

A comparative investigation into relative bond strengths of Damon3, Damon3MX, and APC II brackets using different primer and adhesive combinations.  

PubMed

This investigation measured and compared shear bond strength (SBS) and adhesive remnant indices (ARIs) of Damon3 and Damon3MX brackets bonded with their recommended primer/adhesive combination or Transbond XT primer/adhesive, with APC II brackets bonded using Transbond XT. Sixty non-carious human third molars were collected and randomly divided into six equal groups of 10. Amongst these, one group was used to standardize the testing methodology, with the remainder constituting the five experimental groups. Upper right central incisor brackets represented each bracket type. Specifically, Damon3 brackets were bonded using either OrthoSolo primer/Blugloo (recommended) or Transbond XT primer/adhesive; Damon3MX brackets were bonded using OrthoSolo primer/Grengloo (recommended) or Transbond XT primer/adhesive, and APC II brackets were bonded with Transbond XT primer. Brackets were debonded by shear force using an Instron machine and the SBS measured. Scores for ARI were determined for all groups after bracket failure by magnified inspection of the tooth surface. Logrank tests showed a significantly higher SBS with Damon3 brackets bonded with OrthoSolo/Blugloo compared with Transbond XT, but no significant differences between the SBS of Damon3MX brackets bonded with OrthoSolo/Grengloo compared with Transbond XT. There were no significant differences in SBS of all three bracket types when bonded with Transbond XT. Pearson's chi-square test showed no difference in the locus of debond. All three adhesive systems are reliable when bonding Damon3 and Damon3MX brackets. Some caution should be taken when using Damon3 brackets bonded with OrthoSolo/Blugloo due to the higher SBS, although no enamel fractures were noted in this study. PMID:22015821

Izadi, Maryam I; Sherriff, Martyn; Cobourne, Martyn T

2012-12-01

35

Process qualification and testing of LENS deposited AY1E0125 D-bottle brackets.  

SciTech Connect

The LENS Qualification team had the goal of performing a process qualification for the Laser Engineered Net Shaping{trademark}(LENS{reg_sign}) process. Process Qualification requires that a part be selected for process demonstration. The AY1E0125 D-Bottle Bracket from the W80-3 was selected for this work. The repeatability of the LENS process was baselined to determine process parameters. Six D-Bottle brackets were deposited using LENS, machined to final dimensions, and tested in comparison to conventionally processed brackets. The tests, taken from ES1E0003, included a mass analysis and structural dynamic testing including free-free and assembly-level modal tests, and Haversine shock tests. The LENS brackets performed with very similar characteristics to the conventionally processed brackets. Based on the results of the testing, it was concluded that the performance of the brackets made them eligible for parallel path testing in subsystem level tests. The testing results and process rigor qualified the LENS process as detailed in EER200638525A.

Atwood, Clinton J.; Smugeresky, John E. (Sandia National Labs, Livermore,CA); Jew, Michael (Sandia National Labs, Livermore,CA); Gill, David Dennis; Scheffel, Simon (Sandia National Labs, Livermore,CA)

2006-11-01

36

Surface stress-based biosensors.  

PubMed

Surface stress-based biosensors, as one kind of label-free biosensors, have attracted lots of attention in the process of information gathering and measurement for the biological, chemical and medical application with the development of technology and society. This kind of biosensors offers many advantages such as short response time (less than milliseconds) and a typical sensitivity at nanogram, picoliter, femtojoule and attomolar level. Furthermore, it simplifies sample preparation and testing procedures. In this work, progress made towards the use of surface stress-based biosensors for achieving better performance is critically reviewed, including our recent achievement, the optimally circular membrane-based biosensors and biosensor array. The further scientific and technological challenges in this field are also summarized. Critical remark and future steps towards the ultimate surface stress-based biosensors are addressed. PMID:23948243

Sang, Shengbo; Zhao, Yuan; Zhang, Wendong; Li, Pengwei; Hu, Jie; Li, Gang

2014-01-15

37

Adjustable Bracket For Entry Of Welding Wire  

NASA Technical Reports Server (NTRS)

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.

Gilbert, Jeffrey L.; Gutow, David A.

1993-01-01

38

Intramural Sports -Team Tennis Bracket Spring 2014  

E-print Network

Intramural Sports - Team Tennis Bracket Spring 2014 Poachers (12) Lambda Chi and Friends Sunday and Friends Tennis Is Sexy Champions Phi Psi Sunday, June 1st 7:00pm Tennis is Sexy (31) Tuesday, May 27th 9:00pm Phi Psi (FF) Our Team's No Djokavic Tuesday, June 3rd Team Top Spin (23) 9:00pm Tennis Sexy (13

Escher, Christine

39

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

PubMed Central

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

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

2012-01-01

40

A Lie Bracket Approximation for Extremum Seeking Vehicles  

E-print Network

A Lie Bracket Approximation for Extremum Seeking Vehicles Hans-Bernd D¨urr Milos S. Stankovi as input-affine systems with periodic excitations and by using the methodology of Lie brackets, we existing methods. By examining this approximate Lie bracket system, we are able to directly derive

Johansson, Karl Henrik

41

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

PubMed Central

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

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

2014-01-01

42

Effect of an acidic primer on shear bond strength of orthodontic brackets  

Microsoft Academic Search

A unique characteristic of some new etching systems is that they combine the conditioning and priming agents into a single acidic primer solution. The purpose of this study was to determine the effects on the shear bond strength and the bracket\\/adhesive failure mode when an acidic primer and other enamel etchants were used to condition the enamel surface before bonding.

Samir E. Bishara; Valeria V. Gordan; Leigh VonWald; Marc E. Olson

1998-01-01

43

In vitro bracket bond strength to acid-etched or air-abraded enamel  

Microsoft Academic Search

Purpose: This study evaluated, in vitro, the capacity of a den- tin bonding agent to improve the bond strength of orthodontic brackets using air abrasion enamel preparation. Methods: Each of the enamel surfaces received a different treat- ment prior to bonding procedures. Group 1 received acid-etched with 38% phosphoric acid for 30 seconds. Group 2 received acid- etched with 38%

Kathy Mulcahey; Angelo A. Caputo; Donald F. Duperon

1999-01-01

44

Metal strength of direct bonding brackets.  

PubMed

Because the strength of direct bonding brackets is both important and difficult to measure, a related property, microhardness, has been investigated. Twelve popular U.S. brands of direct bonding brackets have been tested with a Vickers-Hanemann microhardness apparatus. The tests have shown a consistently wide difference in hardness between brands, the highest values being exhibited by those using the precipitation hardened steel known as PH 17-4, and the lowest by those using the austenitic 316L. As the first steel proved to be significantly less corrosion resistant than the last one, it seems that today there are too few attachments that are both strong and chemically resistant. PMID:9517719

Matasa, C G

1998-03-01

45

A stainless steel bracket for orthodontic application.  

PubMed

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

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

2005-06-01

46

Conceptual design for PSP mounting bracket  

SciTech Connect

Protective structural packages (PSP`s or overpacks) used to ship 2 1/2-ton UF{sub 6} 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.

Ransom, G.; Stein, R. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

1991-12-31

47

A Comparison of Gender and Socioeconomic Bracket in Fourth Grade Students when Measuring Volume  

NASA Astrophysics Data System (ADS)

The goal of this study was to assess students' abilities when measuring volume as well as providing a hands-on method for designing a water-filtration process. I studied the trends among gender, time, and ability to measure water in two different groups of fourth grade students. Fourth grade students from both higher income and lower income school districts visited a STEM (Science, Technology, Engineering, and Mathematics) Studio in order to participate in hands-on, problem-based learning. The students in this study attempted to solve the "Dirty Water Problem" by measuring 281ml of dirty water solution, and using household tools to filter and clean the dirty water. This study showed that 68% of students from a high-income socioeconomic bracket were able to measure a determined volume of water independently. Meanwhile, only 18% of students from a low-income socioeconomic bracket were able to complete the same task independently. In the low-income bracket, 78% of students required assistance measuring a volume of water, indicating that the majority of these students performed below grade level. Where time spent at the station was concerned, the difference between high-income and low-income socioeconomic brackets was insignificant. Key Words: STEM, measurement, volume, design, Dirty Water Problem, socioeconomic bracket.

Jennings, Kelly A.

48

Effects of Fluorosis and Bleaching on Shear Bond Strengths of Orthodontic Brackets  

PubMed Central

Objectives To evaluate the effects of fluorosis and bleaching on shear bond strengths of orthodontic brackets. Methods A total of 45 (30 fluorosed and 15 non-fluorosed) non-carious freshly extracted human permanent premolar teeth which were extracted for orthodontic reasons and without any caries or visible defects were used in this study. Fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index (TFI), which is based on the clinical changes in fluorosed teeth. First group consisted of 15 fluorosed teeth. Second group of fluorosed teeth were bleached with a 35% hydrogen peroxide office bleaching agent. Third group served as control. No bleaching procedure was applied. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, shear bond strengths of the brackets were tested with Universal testing machine. Results The results showed that fluorosis only and bleaching of fluorosed teeth significantly reduced the bond strengths of the orthodontic brackets (P < .001). Although bleaching of fluorosed teeth decreased the values more, no statistically significant difference was found between fluorosis group and fluorosis+bleaching group (P > .05). Conclusions Fluorosis and bleaching of fluorosed teeth reduce bracket bond strength to enamel, but the bond strength with these still exceed the minimum 6 to 8 MPa required to expect adequate clinical performance. PMID:19212472

Adanir, Necdet; Türkkahraman, Hakan; Güngör, Ahmet Yalç?n

2007-01-01

49

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

PubMed Central

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

2014-01-01

50

Peierls brackets in non-Lagrangian field theory  

NASA Astrophysics Data System (ADS)

The concept of Lagrange structure allows one to systematically quantize the Lagrangian and non-Lagrangian dynamics within the path-integral approach. In this paper, I show that any Lagrange structure gives rise to a covariant Poisson bracket on the space of solutions to the classical equations of motion, be they Lagrangian or not. The bracket generalize the well-known Peierls' bracket construction and make a bridge between the path-integral and the deformation quantization of non-Lagrangian dynamics.

Sharapov, A. A.

2014-10-01

51

Frictional forces related to self-ligating brackets.  

PubMed

Orthodontic tooth movement can be regarded as teeth sliding on a wire like pearls on a string, the force being supplied by springs or elastics. The movement implies friction between wire and bracket, taking up part of the force and leaving an uncontrolled amount to act on the teeth. The friction is likely to depend on bracket construction and wire material. Therefore, in this investigation the friction of self-ligating brackets and beta-titanium wires was evaluated, as opposed to more conventional configurations. Carried by low-friction linear ball bearings, a bracket was made to slide along an out-stretched archwire with minimal (and known) basic friction, either parallel or at an angle to the wire. Two self-ligating brackets were used in their closed position without any normal force. Friction was tested against four wires: stainless steel and beta-titanium, both in round and rectangular cross-sections. The force used to overcome friction and to move the bracket was measured on a testing machine at 10 mm/min, and the basic friction was subtracted. The results show that round wires had a lower friction than rectangular wires, the beta-titanium wires had a markedly higher friction than stainless steel wires, and friction increased with angulation for all bracket/wire combinations. The self-ligating brackets had a markedly lower friction than conventional brackets at all angulations, and self-ligating brackets, closed by the capping of a conventional design, exhibited a significantly lower friction than self-ligating brackets closed by a spring. The selection of bracket design, wire material, and wire cross-section significantly influences the forces acting in a continuous arch system. PMID:9699406

Pizzoni, L; Ravnholt, G; Melsen, B

1998-06-01

52

Peierls brackets in non-Lagrangian field theory  

E-print Network

The concept of Lagrange structure allows one to systematically quantize the Lagrangian and non-Lagrangian dynamics within the path-integral approach. In this paper, I show that any Lagrange structure gives rise to a covariant Poisson brackets on the space of solutions to the classical equations of motion, be they Lagrangian or not. The brackets generalize the well-known Peierls' bracket construction and make a bridge between the path-integral and the deformation quantization of non-Lagrangian dynamics.

Sharapov, Alexey

2014-01-01

53

The sh Lie structure of Poisson brackets in field theory  

E-print Network

A general construction of an sh Lie algebra from a homological resolution of a Lie algebra is given. It is applied to the space of local functionals equipped with a Poisson bracket, induced by a bracket for local functions along the lines suggested by Gel'fand, Dickey and Dorfman. In this way, higher order maps are constructed which combine to form an sh Lie algebra on the graded differential algebra of horizontal forms. The same construction applies for graded brackets in field theory such as the Batalin-Fradkin-Vilkovisky bracket of the Hamiltonian BRST theory or the Batalin-Vilkovisky antibracket.

G. Barnich; R. Fulp; T. Lada; J. Stasheff

1997-02-25

54

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

PubMed Central

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.

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

2014-01-01

55

Effect of self-etching primer/adhesive and conventional bonding on the shear bond strength in metallic and ceramic brackets  

PubMed Central

Introduction: Bracket debonding from the tooth surface is a common problem in fixed orthodontics. The aims of the present study were to assess the bond strength and failure sites in two ways of bonding technique, with metallic and ceramic brackets. Material and Methods: One hundred premolars were assigned to 4 groups of 25 each: Group A, metallic brackets/ conventional procedure; Group B, metallic brackets/Transbond XT; Group C, ceramic brackets/conventional procedure; and Group D, ceramic brackets/Transbond XT. Transbond XT composite paste was used for bracket bonding and cured by conventional light-cure device. Specimens were subjected to thermocycling. One week after bonding shearing force was applied to the bracket-tooth interface. Bonding failure site optically examined using a stereomicroscope under 10 × magnifications and scoring was done using the adhesive remnant index (ARI). Data were subjected to analysis of One-way variance, Tukey post hoc, Chi-square and Spearman’s tests. Results: Mean bond strength (in MPa) were: group A=9.2, group B=8.5, group C=6.2 and group D=5.7. Bond strength differences between groups A and B, and between C and D were not significant, (p<0.0005). Insignificant difference found in ARI in all groups. Conclusion: The bond strengths of metallic brackets were significantly higher than ceramic ones and the selfetching primer produce fewer bonds than the conventional method (clinically acceptable). A positive correlation found between changes in shearing bond strength and ARI. Key words: Acid etching, adhesive remnant index, orthodontic brackets, self-etching primer, shearing bond strength. PMID:21743430

Kimyai, Soodabeh; Hydari, Mahboubeh; Shahrbaf, Shirin; Mirzakouchaki-Boroujeni, Parvin

2012-01-01

56

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 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...

2011-04-01

57

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 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...

2010-04-01

58

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

... 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...

2014-04-01

59

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2012 CFR

... 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...

2012-04-01

60

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.  

Code of Federal Regulations, 2013 CFR

... 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...

2013-04-01

61

A VARIATIONAL APPROACH FOR THE FUSION OF BRACKETING IMAGES  

E-print Network

A VARIATIONAL APPROACH FOR THE FUSION OF BRACKETING IMAGES By Marcelo Bertalm´io and Stacey Levine with motion pictures, which suffer from the same limitations. There are several related works on image fusion: 612-626-7370 URL: http://www.ima.umn.edu #12;1 A Variational Approach for the Fusion of Bracketing

62

Online dectection device for assembly of automotive sliding york bracket  

Microsoft Academic Search

This Online Sliding york bracket is one of the most important shift parts in automotive transmission. The traditional detection mostly depends on artificial methods, which cost large amount of labor and easily lead to the fatigue of naked eyes. In this article we have developed the object, clearance detection sensor. Considering the assembly feature of the sliding york bracket, we

Chundong Zhu; Zhiliang Zhu

2010-01-01

63

RSRM nozzle actuator bracket/lug fracture mechanics qualification test  

NASA Technical Reports Server (NTRS)

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.

Kelley, Peggy

1993-01-01

64

RSRM nozzle actuator bracket/lug fracture mechanics qualification test  

NASA Astrophysics Data System (ADS)

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.

Kelley, Peggy

1993-07-01

65

[Enamel abrasion and enamel tears by porcelain brackets].  

PubMed

Orthodontic brackets manufactured of poly- or monocrystalline alumina ceramics are aesthetically appealing, but unfortunately show disadvantages for clinical application primarily causing (1) Abrasions of the enamel of antagonistic teeth, and (2) Tear-outs of the underlying enamel through debonding. To determine whether hardness and/or textural and structural qualities of the ceramics (as characterized by SEM investigations) are responsible for the deleterious clinical effects of abrasion, the amount of decrease of the height of human enamel-molar-cusps was measured. Enamel loss was shown to be significantly more than 100 microns at 10 min. operating time in an abrasive testing device. Also debonding of the ceramic brackets proved to be problematic. Whereas metals and polymeric brackets allow some deflection of the material in addition to the tensile stress, separating the bracket from the enamel at the bracket-to-adhesive interface, or within the adhesive composite, the lacking workability in the ceramic brackets may induce a shift of the break-line during debonding to the adhesive-enamel interface or even into the dental enamel. Development and clinical application of ceramic brackets should improve safety for the enamel. Regardless of ceramic brand the abrasiveness endangers enamel through ceramic/enamel interferences. To avoid tear-out defects, brackets should debond at the ceramic-adhesive interface. PMID:2699879

Newesely, H; Rossiwall, B

1989-01-01

66

Transparent magnesium aluminate spinel: a prospective biomaterial for esthetic orthodontic brackets.  

PubMed

Adult orthodontics is recently gaining popularity due to its importance in esthetics, oral and general health. However, none of the currently available alumina or zirconia based ceramic orthodontic brackets meet the esthetic demands of adult patients. Inherent hexagonal lattice structure and associated birefringence limits the visible light transmission in polycrystalline alumina and make them appear white and non transparent. Hence focus of the present study was to assess the feasibility of using magnesium aluminate (MgAl2O4) spinel; a member of the transparent ceramic family for esthetic orthodontic brackets. Transparent spinel specimens were developed from commercially available white spinel powder through colloidal shaping followed by pressureless sintering and hot isostatic pressing at optimum conditions of temperature and pressure. Samples were characterized for chemical composition, phases, density, hardness, flexural strength, fracture toughness and optical transmission. Biocompatibility was evaluated with in-vitro cell line experiments for cytotoxicity, apoptosis and genotoxicity. Results showed that transparent spinel samples had requisite physico-chemical, mechanical, optical and excellent biocompatibility for fabricating orthodontic brackets. Transparent spinel developed through this method demonstrated its possibility as a prospective biomaterial for developing esthetic orthodontic brackets. PMID:25027301

Krishnan, Manu; Tiwari, Brijesh; Seema, Saraswathy; Kalra, Namitha; Biswas, Papiya; Rajeswari, Kotikalapudi; Suresh, Madireddy Buchi; Johnson, Roy; Gokhale, Nitin M; Iyer, Satish R; Londhe, Sanjay; Arora, Vimal; Tripathi, Rajendra P

2014-11-01

67

In vitro evaluation of corrosion and cytotoxicity of orthodontic brackets.  

PubMed

The corrosion resistance of AISI 304 stainless steel (AISI 304 SS) and manganese stainless steel (low-nickel SS) brackets in artificial saliva was investigated. The cytotoxic effects of their corrosion products on L929 cell culture were compared by two assays, crystal violet, to evaluate cell viability, and MTT (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide), for cell metabolism and proliferation. The atomic absorption spectroscopic analysis of the corrosion products demonstrated that nickel and manganese ion concentrations were higher for the AISI 304 SS-bracket immersion solution as compared with the low-nickel SS brackets. Scanning electron microscopy and energy-dispersive spectroscopy demonstrated less corrosion resistance for the AISI 304 SS brackets. Although none of the bracket extracts altered L929 cell viability or morphology, the AISI 304 SS-bracket extracts decreased cellular metabolism slightly. The results indicated that the low-nickel SS presents better in vitro biocompatibility than AISI 304 SS brackets. Abbreviations used: AISI, American Iron and Steel Institute; EDS, energy-dispersive spectroscopy; OD, optical density; ISO, International Organization for Standardization; MTT, (3-{4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NiSO(4), nickel sulfate; SEM, standard error of the mean; WHO, World Health Organization; and TNF, tumor necrosis factor. PMID:17452565

Costa, M T; Lenza, M A; Gosch, C S; Costa, I; Ribeiro-Dias, F

2007-05-01

68

Frictional characteristics of composite orthodontic archwires against stainless steel and ceramic brackets in the passive and active configurations.  

PubMed

The frictional characteristics of prototype composite archwires were investigated. The resistance to sliding was measured in the dry state for wires with three different volume fractions of fiber reinforcement against stainless steel, polycrystalline alumina, and single crystal alumina orthodontic brackets. Each archwire and bracket combination was tested at 34 degrees C with twelve different normal forces (from 0-400 g) and six different angulations (from 0 degrees -12.5 degrees ). The kinetic coefficients of friction were determined from the slopes of linear regressions through plots of the resistance to sliding versus normal force data. The y-intercepts of these regressions were also evaluated as indicators of the binding magnitude. The tested archwire samples were examined for wear using a scanning electron microscope. A fully factorial model analysis-of-variance showed no significant differences in the frictional coefficients for changes in bracket material, reinforcement level, or angulation. Highly significant differences were observed in the y-intercepts for changes in the reinforcement level and angulation. Highly significant, positive, and linear correlations between the y-intercepts and angulations were also established. Abrasive wear of the composite surface was observed at the archwire-bracket interface, particularly at higher normal forces and angulations. Relative to other frictional studies of metallic archwire materials, the composite archwires had higher kinetic coefficients of friction than stainless steel but lower coefficients than either nickel titanium or beta-titanium archwires against all bracket materials tested. PMID:15348678

Zufall, S W; Kennedy, K C; Kusy, R P

1998-11-01

69

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

PubMed Central

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

Ahrari, Farzaneh; Poosti, Maryam; Motahari, Pourya

2012-01-01

70

The bracket-hack package Christopher Roman Nerz  

E-print Network

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

Ould Ahmedou, Mohameden

71

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

72

Detail view to show the stylized "dragon" bracket feature that ...  

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

Detail view to show the stylized "dragon" bracket feature that stands guard by the outside door to the kitchen (north elevation of the main house) - Death Valley Ranch, Main House, Death Valley Junction, Inyo County, CA

73

Analysis of Bracket Assembly for Portable Leak Detector Station  

SciTech Connect

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).

ZIADA, H.H.

1999-08-19

74

Detail view of door surround, note bracket & ghost of ...  

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

Detail view of door surround, note bracket & ghost of (former) arched opening in the brickwork beside it - Leonard Mackall House, 1686 Thirty-Fourth Street, Northwest, Washington, District of Columbia, DC

75

The sh Lie Structure of Poisson Brackets in Field Theory  

Microsoft Academic Search

:  A general construction of an sh Lie algebra (L\\u000a \\u000a ?-algebra) from a homological resolution of a Lie algebra is given. It is applied to the space of local functionals equipped\\u000a with a Poisson bracket, induced by a bracket for local functions along the lines suggested by Gel'fand, Dickey and Dorfman.\\u000a In this way, higher order maps are constructed which combine

G. Barnich; R. Fulp; T. Lada; J. Stasheff

1998-01-01

76

Devices based on surface plasmon interference filters  

NASA Technical Reports Server (NTRS)

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.

Wang, Yu (Inventor)

2001-01-01

77

Surface Pretreatment Based On Dilute Hexafluorozirconic Acid  

Microsoft Academic Search

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

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

78

Vibration based on liquid surface tension  

Microsoft Academic Search

In this paper, vibration based on liquid surface tension is reported. A prototype vibrator composed of a water film sandwiched between two plates is fabricated and tested. The free and the continuous vibrations (electromagnetic drive) of the proposed vibrator are demonstrated. The mechanical model of the vibrator is also presented. Theoretical analysis and experiments prove the surface tension, which has

Xing Yang; Xiao Yan Ren; Dan Li; Man Rui Ren; Jia Rui Yang; Zhao Ying Zhou; Quan Shui Zheng

2011-01-01

79

HOTB: High precision parallel code for calculation of four-particle harmonic oscillator transformation brackets  

NASA Astrophysics Data System (ADS)

This new version of the HOTB program for calculation of the three and four particle harmonic oscillator transformation brackets provides some enhancements and corrections to the earlier version (Germanas et al., 2010) [1]. In particular, new version allows calculations of harmonic oscillator transformation brackets be performed in parallel using MPI parallel communication standard. Moreover, higher precision of intermediate calculations using GNU Quadruple Precision and arbitrary precision library FMLib [2] is done. A package of Fortran code is presented. Calculation time of large matrices can be significantly reduced using effective parallel code. Use of Higher Precision methods in intermediate calculations increases the stability of algorithms and extends the validity of used algorithms for larger input values. Catalogue identifier: AEFQ_v4_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFQ_v4_0.html Program obtainable from: CPC Program Library, Queen’s University of Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 Number of lines in programs, including test data, etc.: 1711 Number of bytes in distributed programs, including test data, etc.: 11667 Distribution format: tar.gz Program language used: FORTRAN 90 with MPI extensions for parallelism Computer: Any computer with FORTRAN 90 compiler Operating system: Windows, Linux, FreeBSD, True64 Unix Has the code been vectorized of parallelized?: Yes, parallelism using MPI extensions. Number of CPUs used: up to 999 RAM(per CPU core): Depending on allocated binomial and trinomial matrices and use of precision; at least 500 MB Catalogue identifier of previous version: AEFQ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 181, Issue 2, (2010) 420-425 Does the new version supersede the previous version? Yes Nature of problem: Calculation of matrices of three-particle harmonic oscillator brackets (3HOB) and four-particle harmonic oscillator brackets (4HOB) in a more effective way, which allows us to calculate matrix of the brackets up to a few hundred times more rapidly and more accurate than in a previous version. Solution method: Using external parallelization libraries and mutable precision we created a pack of numerical codes based on the methods of compact expressions of the three and four-particle harmonics oscillator brackets 3HOB, 4HOB, presented in [3]. Restrictions: For double precision version calculations can be done up to harmonic oscillator (HO) energy quanta e=28. For quadruple precision mantissa is equal to approximately 34 decimal digits, therefore calculations can be done up to HO energy quanta to e=52. Running time: The running time depends on the harmonic oscillator energy quanta, cluster size and the precision of intermediate calculations. More information on Table 1 for 3HOB and Table 2 for 4HOB. Reasons for a new version: The new program version expands the limits of harmonic oscillator energy quanta and gives shorter calculation time. Extend the limits of calculation of HOB First version was able to produce harmonic oscillator transformation brackets for three and four particles if E?HO energy quanta. With this version of our program, if quadruple or arbitrary precision functions are being used, it is possible to calculate three and four particle harmonic oscillator transformation brackets for greater values of energy and momenta, while sustaining tolerable margin of error. Calculation time As the code of previous version of program was redone using parallelism paradigma, it is now possible to reduce the calculation time of transformation matrices significantly, depending on the size of computing cluster, as the dimensions of matrices are growing very rapidly according to the energy and momenta values. subroutinematrix_4HOB_dimensionCalculates the dimension of 4HOB matrix. subroutinematrix_3HOB_dimensionCalculates the dimension of 3HOB matrix, subroutinematrix_3HOBCalculates the global state array which is used in parallel calculation of 3HOB matrix. subroutinematrix_4HOBCalculates the global sta

Stepšys, A.; Mickevicius, S.; Germanas, D.; Kalinauskas, R. K.

2014-11-01

80

Vibration based on liquid surface tension  

NASA Astrophysics Data System (ADS)

In this paper, vibration based on liquid surface tension is reported. A prototype vibrator composed of a water film sandwiched between two plates is fabricated and tested. The free and the continuous vibrations (electromagnetic drive) of the proposed vibrator are demonstrated. The mechanical model of the vibrator is also presented. Theoretical analysis and experiments prove the surface tension, which has the advantages of the no-mechanical parts, simple-structure, and self-lubrication, is effective for driving. The liquid surface tension vibrator demonstrates the potential applications in resonating sensors, precision actuator, and mechanical switch.

Yang, Xing; Ren, Xiao Yan; Li, Dan; Ren, Man Rui; Yang, Jia Rui; Zhou, Zhao Ying; Zheng, Quan Shui

2011-01-01

81

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

PubMed

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

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

2013-10-01

82

Structural Analysis of the Redesigned Ice/Frost Ramp Bracket  

NASA Technical Reports Server (NTRS)

This paper describes the interim structural analysis of a redesigned Ice/Frost Ramp bracket for the Space Shuttle External Tank (ET). The proposed redesigned bracket consists of mounts for attachment to the ET wall, supports for the electronic/instrument cables and propellant repressurization lines that run along the ET, an upper plate, a lower plate, and complex bolted connections. The eight nominal bolted connections are considered critical in the summarized structural analysis. Each bolted connection contains a bolt, a nut, four washers, and a non-metallic spacer and block that are designed for thermal insulation. A three-dimensional (3D) finite element model of the bracket is developed using solid 10-node tetrahedral elements. The loading provided by the ET Project is used in the analysis. Because of the complexities associated with accurately modeling the bolted connections in the bracket, the analysis is performed using a global/local analysis procedure. The finite element analysis of the bracket identifies one of the eight bolted connections as having high stress concentrations. A local area of the bracket surrounding this bolted connection is extracted from the global model and used as a local model. Within the local model, the various components of the bolted connection are refined, and contact is introduced along the appropriate interfaces determined by the analysts. The deformations from the global model are applied as boundary conditions to the local model. The results from the global/local analysis show that while the stresses in the bolts are well within yield, the spacers fail due to compression. The primary objective of the interim structural analysis is to show concept viability for static thermal testing. The proposed design concept would undergo continued design optimization to address the identified analytical assumptions and concept shortcomings, assuming successful thermal testing.

Phillips, D. R.; Dawicke, D. S.; Gentz, S. J.; Roberts, P. W.; Raju, I. S.

2007-01-01

83

Lie Bracket of Vector Fields in Noncommutative Geometry  

NASA Astrophysics Data System (ADS)

The aim of this paper is to avoid some difficulties, related with the Lie bracket, in the definition of vector fields in a noncommutative setting, as they were defined by Woronowicz, Schmüdgen-Schüler and Aschieri-Schupp. We extend the definition of vector fields to consider them as derivations of the algebra, through Cartan pairs introduced by Borowiec. Then, using translations, we introduce the invariant vector fields. Finally, the definition of Lie bracket realized by Dubois-Violette, considering elements in the center of the algebra, is also extended to these invariant vector fields.

Jara, P.; Llena, D.

2003-09-01

84

Galvanic corrosion behavior of orthodontic archwire alloys coupled to bracket alloys.  

PubMed

The purpose of this study was to provide a quantitative assessment of galvanic corrosion behavior of orthodontic archwire alloys coupled to orthodontic bracket alloys in 0.9% NaCl solution and to study the effect of surface area ratios. Two common bracket alloys, stainless steels and titanium, and four common wire alloys, nickel-titanium (NiTi) alloy, beta-titanium (beta-Ti) alloy, stainless steel, and cobalt-chromium-nickel alloy, were used. Three different area ratios, 1:1, 1:2.35, and 1:3.64, were used; two of them assumed that the multibracket appliances consists of 14 brackets and 0.016 inch of round archwire or 0.016 x 0.022 inch of rectangular archwire. The galvanic current was measured for 3 successive days using zero-impedance ammeter. When the NiTi alloy was coupled with Ti (1:1, 1:2.35, and 1:3.64 of the surface area ratio) or beta-Ti alloy was coupled with Ti (1:2.35 and 1:3.64 of the surface area ratio), Ti initially was the anode and corroded. However, the polarity reversed in 1 hour, resulting in corrosion of the NiTi or beta-Ti. The NiTi alloy coupled with SUS 304 or Ti exhibited a relatively large galvanic current density even after 72 hours. It is suggested that coupling SUS 304-NiTi and Ti-NiTi may remarkably accelerate the corrosion of NiTi alloy, which serves as the anode. The different anode-cathode area ratios used in this study had little effect on galvanic corrosion behavior. PMID:16808581

Iijima, Masahiro; Endo, Kazuhiko; Yuasa, Toshihiro; Ohno, Hiroki; Hayashi, Kazuo; Kakizaki, Mitsugi; Mizoguchi, Itaru

2006-07-01

85

Vibration-Based Surface Recognition for Smartphones  

E-print Network

Vibration-Based Surface Recognition for Smartphones Jungchan Cho, Inhwan Hwang, and Songhwai Oh in a smartphone, it is now possible to obtain information about a user and her surround- ings, such as the location of a smartphone and the activity of the smartphone user, and the obtained context information

86

MASTER THESIS Surface-based mapping of  

E-print Network

MASTER THESIS Surface-based mapping of the serotonin transporter binding in cerebral cortex was on the cerebral cortex due to its highly-folded and thin structure, which makes it particularly unsuited intrinsic geometry of cerebral cortex into account in the filtering and modeling by the mul- tilinear

87

Convolution Surfaces based on Polygonal Curve Skeletons  

E-print Network

Convolution Surfaces based on Polygonal Curve Skeletons An Application of Symbolic Integration skeletons that are lower dimensional or simpler geometric models of the shape to be created. Convolution this skeleton. To allow interactive modeling, the technique has relied on closed form formulae for integration

88

Convolution Surfaces based on Polygonal Curve Skeletons  

E-print Network

Convolution Surfaces based on Polygonal Curve Skeletons Evelyne Hubert a aINRIA Sophia Antipolis Graphics to generate smooth 3D volumes around skeletons that are lower dimensional or simpler geometric by integrating a kernel func- tion along this skeleton. To allow interactive modeling, the technique has relied

Paris-Sud XI, Université de

89

Comparison of deformation and torque expression of the orthos and orthos Ti bracket systems.  

PubMed

Orthodontic torque expression is the result of axial rotation of rectangular archwires within a rectangular bracket slot. This study investigates the effect of bracket material on torque expression. Torque exerted by a rotating archwire on each bracket will be measured as well as the relative deformation of each bracket slot. A total of 60 tests were performed where archwires were rotated within a bracket slot to produce torque within a bracket. Thirty Ormco Orthos Ti and 30 Orthos SS were compared to investigate the effect of torque on bracket material. Each bracket was mounted on a six-axis load cell that measured forces and moments in all directions. The archwire was rotated from an initial angle of 0 degree in 3 degrees increments to maximum angle of 51 degrees and then returned to the initial position. An overhead camera took images at each 3 degrees increment. The bracket images were post-processed using a digital image correlation technique to measure the relative deformation of each bracket slot. The maximum torque expressed at 51 degrees was 99.8 Nmm and 93.0 Nmm for Orthos Ti and Orthos SS, respectively. Total plastic deformation measured at 0 degrees post-torquing of the Orthos SS was 0.038 mm compared to 0.013 mm for Orthos Ti. The Orthos Ti brackets plastically deformed less than the Orthos SS brackets after torquing. The Orthos SS bracket plastic deformation was 2.8 times greater than that of Orthos Ti brackets. The Orthos Ti brackets expressed more torque than the stainless steel brackets but exhibited substantial variation. PMID:22015820

Melenka, Garrett W; Lacoursiere, Ryan A; Carey, Jason P; Nobes, David S; Heo, Giseon; Major, Paul W

2014-08-01

90

In-vitro evaluation of an experimental method for bonding of orthodontic brackets with self-adhesive resin cements  

PubMed Central

Background Self-adhesive resin cements do not require the surface treatment of teeth and are said to release fluoride, which makes them suitable candidates for bonding of orthodontic brackets. The objectives of this study was to investigate the shear bond strength (SBS) of self-adhesive resin cements on etched on non-etched surfaces in vitro and to assess their fluoride release features. Materials and Methods Four fluoride-releasing dual-cure self-adhesive resin cements were investigated. For SBS experiment, 135 freshly extracted human maxillary premolars were used and divided into nine groups of 15 teeth. In the control group, brackets were cemented by Transbond XT (3M Unitek, USA), in four groups self-adhesive resin cements were used without acid-etching and in four groups self-adhesive cements were applied on acid-etched surfaces and the brackets were then deboned in shear with a testing machine. Adhesive remnant index (ARI) scores were also calculated. For fluoride release investigation, 6 discs were prepared for each self-adhesive cement. Transbond XT and Fuji Ortho LC (GC, Japan) served as negative and positive control groups, respectively. The fluoride release of each disc into 5 ml of deionized water was measured at days 1, 2, 3, 7, 14, 28, and 56 using a fluoride ion-selective electrode connected to an ion analyzer. To prevent cumulative measurements, the storage solutions were changed daily. Results The SBS of brackets cemented with Transbond XT were significantly higher compared to self-adhesives applied on non-etched surfaces (P<0.001). However, when the self-adhesive resin cements were used with enamel etching, no significant differences was found in the SBS compared to Transbond XT, except for Breeze. The comparisons of the ARI scores indicated that bracket failure modes were significantly different between the etched and non-etched groups. All self-adhesive cements released clinically sufficient amounts of fluoride for an extended period of time. Conclusion For the tested cements, the strongest bonds were obtained by enamel acid-etching prior to bracket bonding. All the self-adhesive resin cements had significant long-term fluoride release and could be recommended as suitable fluoride-releasing orthodontic bonding materials. PMID:24163808

Ramazanzadeh, Barat Ali; Merati, Mohsen; Shafaee, Hooman; Dogon, Leon; Sohrabi, Keyvan

2013-01-01

91

Methods without secant steps for finding a bracketed root  

Microsoft Academic Search

A number of methods that require only function evaluation to find a bracketed root are discussed. The Snyder, Pegasus, and Anderson-Björck schemes of Regula Falsi type converge superlinearly, but all use relatively slow secant steps. Two recent methods are faster because they exploit the rational interpolation step used by Anderson and Björck, and virtually eliminate secant steps.

R. F. King

1976-01-01

92

Analysis of Bracket Assembly for Diversion Box Leak Detector  

SciTech Connect

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).

ZIADA, H.H.

1999-08-19

93

Untersuchungen zur Haftfestigkeit von Brackets mit und ohne Silanisierung  

Microsoft Academic Search

Zusammenfassung Ziel der Untersuchung war es, einen neuen Retentionsmechanismus beim Verbund zwischen Adhäsiv und herkömmlichen Bracket-Basistypen zu evaluieren. Für die Untersuchungen wurden fünf verschiedene Metallbracket-Typen ausgewählt, die unterschiedliche Basen aufwiesen. Die glatten Metallbrackets wurden als Kontrollgruppe herangezogen. Je zehn beschichtete und unbeschichtete Prüfkörper von jeder Gruppe wurden mit Concise Enamel Bond auf die Zähne geklebt und nach 28 Tagen die

N. Akin; I. Nergiz; U. Platzer; J. Ødegaard

1991-01-01

94

The Euler-Poincaré equations and double bracket dissipation  

Microsoft Academic Search

This paper studies the perturbation of a Lie-Poisson (or, equivalently an Euler-Poincaré) system by a special dissipation term that has Brockett's double bracket form. We show that a formally unstable equilibrium of the unperturbed system becomes a spectrally and hence nonlinearly unstable equilibrium after the perturbation is added. We also investigate the geometry of this dissipation mechanism and its relation

Anthony Bloch; P. S. Krishnaprasad; Jerrold E. Marsden; Tudor S. Ratiu

1996-01-01

95

Shear bond strength of self-ligating brackets.  

PubMed

The aim of this study was to compare the shear bond strength (SBS) and adhesive remnant index (ARI) scores of conventional and self-ligating brackets. Conventional stainless steel brackets (group 1, Step; Leone) and three different passive and interactive self-ligating brackets (group 2, Smart Clip, 3M Unitek; group 3, Quick, Forestadent; and group 4, Damon 3MX, Ormco) were tested. Four groups of 20 specimens each were bonded with an adhesive system (Ortho Solo primer, Ormco and Transbond XT resin, 3M Unitek) onto bovine enamel and subsequently tested using an Instron universal testing machine. SBS values and adhesive failure rate were recorded. Statistical analysis was performed with analysis of variance and Scheffé tests to determine bond strength values, whereas a chi-square test was used for ARI scores. Groups 2 and 4 showed significantly higher SBS values than the other two groups. Moreover, groups 1 and 3 showed a higher frequency of ARI score 1, whereas groups 2 and 4 showed higher frequency of ARI score 2. All the brackets demonstrated a clinically adequate SBS. PMID:20660129

Sfondrini, Maria Francesca; Gatti, Sara; Scribante, Andrea

2011-02-01

96

Inside-Outside Reestimation from Partially Bracketed Corpora  

Microsoft Academic Search

The inside-outside algorithm for inferring the parameters of a stochastic context-free grammar is extended to take advantage of constituent information (constituent bracketing) in a partially parsed corpus. Experiments on formal and natural language parsed corpora show that the new algorithm can achieve faster convergence and better modeling of hierarchical structure than the original one. In particular, over 90% test set

Fernando C. N. Pereira; Yves Schabes

1992-01-01

97

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

E-print Network

1 Measurement and Simulation of Distortion of a Steel Bracket Casting D. Galles and C a cast steel bracket. Additional measurements of various bracket features are taken after shakeout is needed to improve agreement. 1. Introduction During cooling of a steel casting, thermal strains

Beckermann, Christoph

98

In vitro evaluation of frictional forces between archwires and ceramic brackets.  

PubMed

The aim of this study was to evaluate the frictional force between orthodontic brackets and archwires. The differences in magnitude of the frictional forces generated by ceramic brackets, ceramic brackets with metal reinforced slot, and stainless steel brackets in combination with stainless steel, nickel-titanium, and beta-titanium orthodontic archwires were investigated. Brackets and wire were tested with tip angulations of 0 degrees and 10 degrees. Friction testing was done with the Emic DL 10000 testing machine (São José do Rio Preto, PR, Brazil), and the wires were pulled from the slot brackets with a speed of 0.5 cm/min for 2 minutes. The ligation force between the bracket and the wire was 200 g. According to the data obtained, the brackets had frictional force values that were statistically significant in this progressive order: stainless steel bracket, ceramic bracket with a metal reinforced slot, and traditional ceramic bracket with a ceramic slot. The beta-titanium wire showed the highest statistically significant frictional force value, followed by the nickel-titanium and the stainless steel archwires, in decreasing order. The frictional force values were directly proportional to the angulation increase between the bracket and the wire. PMID:14718880

Nishio, Clarice; da Motta, Andréa Fonseca Jardim; Elias, Carlos Nelson; Mucha, José Nelson

2004-01-01

99

Effect of remineralizing agents on bond strength of orthodontic brackets: an in vitro study  

PubMed Central

Background The purpose of this study is to evaluate the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and CPP-ACP with fluoride (CPP-ACP-F) on the shear bond strength (SBS) of orthodontic brackets bonded with two different adhesive systems. Methods One hundred twenty-six human premolar teeth were selected. One hundred twenty teeth were used for SBS testing, and six teeth were used for scanning electron microscope (SEM) examination. One hundred twenty premolars were divided into mainly three groups: CPP-ACP (group A), CPP-ACP-F (group B), and control group (group C). Each group was sub-divided into two groups according to the bonding adhesive, light cure (groups A1, B1, and C1) and chemical cure (groups A2, B2, and C2). The teeth were pre-treated with the group-specified preventive agent 1 h/day for five consecutive days. Standard edgewise brackets were bonded with the respective adhesives. SBS evaluation was done with the universal testing machine. After debonding, all the teeth were scored for adhesive remaining on the buccal surface, in accordance to adhesive remnant index, under a stereomicroscope. The acid-etched enamel surfaces were observed under SEM after treatment with CPP-ACP, CPP-ACP-F, and artificial saliva. Result In light-cure adhesive group, CPP-ACP-F (B1) showed superior results compared to the control group (C1), whereas the CPP-ACP group (A1) showed lower mean SBS than the control group (C1). Both these differences were not statistically significant (p?>?0.05). In chemical-cure adhesive group, control group C2 showed significantly superior results (p??0.01). Conclusion The SBS of the orthodontic brackets was non-significantly affected when the brackets were cured with light-cure bonding system and treated with either CPP-ACP or CPP-ACP-F, whereas with chemical-cure adhesive, decreased bond strength was seen, which was within the clinically acceptable limits. PMID:24935482

2014-01-01

100

Adherence of Streptococcus mutans and Candida albicans to different bracket materials  

PubMed Central

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

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

2012-01-01

101

Statistical Seasonal Sea Surface based Prediction Model  

NASA Astrophysics Data System (ADS)

The interannual variability of the sea surface temperature (SST) plays a key role in the strongly seasonal rainfall regime on the West African region. The predictability of the seasonal cycle of rainfall is a field widely discussed by the scientific community, with results that fail to be satisfactory due to the difficulty of dynamical models to reproduce the behavior of the Inter Tropical Convergence Zone (ITCZ). To tackle this problem, a statistical model based on oceanic predictors has been developed at the Universidad Complutense of Madrid (UCM) with the aim to complement and enhance the predictability of the West African Monsoon (WAM) as an alternative to the coupled models. The model, called S4CAST (SST-based Statistical Seasonal Forecast) is based on discriminant analysis techniques, specifically the Maximum Covariance Analysis (MCA) and Canonical Correlation Analysis (CCA). Beyond the application of the model to the prediciton of rainfall in West Africa, its use extends to a range of different oceanic, atmospheric and helth related parameters influenced by the temperature of the sea surface as a defining factor of variability.

Suarez, Roberto; Rodriguez-Fonseca, Belen; Diouf, Ibrahima

2014-05-01

102

In vitro Evaluation of Corrosion and Cytotoxicity of Orthodontic Brackets  

Microsoft Academic Search

The corrosion resistance of AISI 304 stainless steel (AISI 304 SS) and manganese stainless steel (low-nickel SS) brackets in artificial saliva was investigated. The cytotoxic effects of their corrosion products on L929 cell culture were compared by two assays, crystal violet, to evaluate cell viability, and MTT (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide), for cell metabolism and proliferation. The atomic absorption spectroscopic analysis of

M. T. Costa; M. A. Lenza; C. S. Gosch; I. Costa; F. Ribeiro-Dias

2007-01-01

103

Standing surface acoustic wave based cell coculture.  

PubMed

Precise reconstruction of heterotypic cell-cell interactions in vitro requires the coculture of different cell types in a highly controlled manner. In this article, we report a standing surface acoustic wave (SSAW)-based cell coculture platform. In our approach, different types of cells are patterned sequentially in the SSAW field to form an organized cell coculture. To validate our platform, we demonstrate a coculture of epithelial cancer cells and endothelial cells. Real-time monitoring of cell migration dynamics reveals increased cancer cell mobility when cancer cells are cocultured with endothelial cells. Our SSAW-based cell coculture platform has the advantages of contactless cell manipulation, high biocompatibility, high controllability, simplicity, and minimal interference of the cellular microenvironment. The SSAW technique demonstrated here can be a valuable analytical tool for various biological studies involving heterotypic cell-cell interactions. PMID:25232648

Li, Sixing; Guo, Feng; Chen, Yuchao; Ding, Xiaoyun; Li, Peng; Wang, Lin; Cameron, Craig E; Huang, Tony Jun

2014-10-01

104

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

PubMed Central

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

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

2014-01-01

105

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

PubMed Central

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

2014-01-01

106

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

PubMed Central

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

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

2012-01-01

107

Surface-based protein binding pocket similarity.  

PubMed

Protein similarity comparisons may be made on a local or global basis and may consider sequence information or differing levels of structural information. We present a local three-dimensional method that compares protein binding site surfaces in full atomic detail. The approach is based on the morphological similarity method which has been widely applied for global comparison of small molecules. We apply the method to all-by-all comparisons two sets of human protein kinases, a very diverse set of ATP-bound proteins from multiple species, and three heterogeneous benchmark protein binding site data sets. Cases of disagreement between sequence-based similarity and binding site similarity yield informative examples. Where sequence similarity is very low, high pocket similarity can reliably identify important binding motifs. Where sequence similarity is very high, significant differences in pocket similarity are related to ligand binding specificity and similarity. Local protein binding pocket similarity provides qualitatively complementary information to other approaches, and it can yield quantitative information in support of functional annotation. PMID:21769944

Spitzer, Russell; Cleves, Ann E; Jain, Ajay N

2011-09-01

108

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

PubMed Central

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

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

2012-01-01

109

Theoretical study of an efficient bracketing camera system architecture  

NASA Astrophysics Data System (ADS)

Although High Dynamic Range (HDR) imaging has represented, in the recent years, the topic of important researches, it has not reached yet an excellent level of the HDR scenes acquisition using the available components. Indeed, many solutions have been proposed ranging from bracketing to the beamsplitter but none of these solutions is really consistent with the moving scenes representing light's level difference. In this paper, we present an optical architecture, which exploits the stereoscopic cameras, ensuring the simultaneous capture of four different exposures of the same image on four sensors with efficient use of the available light. We also present a short description of the implemented fusion algorithm implemented.

Besrour, Amine; Snoussi, Hichem; Siala, Mohamed; Abdelkefi, Fatma

2014-03-01

110

Options for a lunar base surface architecture  

NASA Technical Reports Server (NTRS)

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.

Roberts, Barney B.

1992-01-01

111

Noncontact Human Force Capturing based on Surface Hardness Measurement  

E-print Network

Noncontact Human Force Capturing based on Surface Hardness Measurement Masahiro Fujiwara method based on skin surface hardness measurement. The measurement system is composed of an airborne ultrasound phased array and a laser displacement sensor. The surface hardness distribution of a human hand

Shinoda, Hiroyuki

112

Image-based Water Surface Reconstruction with Refractive Stereo  

E-print Network

Image-based Water Surface Reconstruction with Refractive Stereo by Nigel Jed Wesley Morris A thesis-based Water Surface Reconstruction with Refractive Stereo Nigel Jed Wesley Morris Master of Science Graduate surfaces using an indirect refractive stereo reconstruction method. Our work builds on previous work

Jepson, Allan D.

113

Electrical servo actuator bracket. [fuel control valves on jet engines  

NASA Technical Reports Server (NTRS)

An electrical servo actuator is mounted on a support arm which is allowed to pivot on a bolt through a fixed mounting bracket. The actuator is pivotally connected to the end of the support arm by a bolt which has an extension allowed to pass through a slot in the fixed mounting bracket. An actuator rod extends from the servo actuator to a crank arm which turns a control shaft. A short linear thrust of the rod pivots the crank arm through about 90 for full-on control with the rod contracted into the servo actuator, and full-off control when the rod is extended from the actuator. A spring moves the servo actuator and actuator rod toward the control crank arm once the actuator rod is fully extended in the full-off position. This assures the turning of the control shaft to a full-off position. A stop bolt and slot are provided to limit pivot motion. Once fully extended, the spring pivots the motion.

Sawyer, R. V. (inventor)

1981-01-01

114

Comparision of Shear Bond Strength of Stainless Steel and Ceramic Brackets at 24 Hours after Etching Enamel with Different Proportions of Acidulated Phosphate Fluoride  

PubMed Central

Aims and Objectives: To evaluate and compare the shear bond strength of stainless steel brackets and ceramic brackets at 24h after etching the enamel with acidulated phosphate fluoride gel (1.23% APF) at different proportions (40%,30%,20%) incorporated in conventional etchant (37% phosphoric acid). Materials and Methods: Eighty premolars (maxillary and mandibular first and second premolars) extracted for orthodontic purpose has been selected for the study and samples were divided into 4 groups containing 10 teeth each. Comprised of teeth etched Group 1 with 40% of APF gel etchant is Group 2 teeth etched with 30% of APF gel in Group 3 teeth etched with 20% of APF gel etchant and Group 4 teeth were etched with conventional etchant (37% phosphoric acid). Results: The experimental group of Acidulated Phosphate Fluoride (APF) at different proportion (40%, 30%, 20%) incorporated with etchant application for 40s on the enamel surface at 24h indicated that group 4 showed the higher bond strength of all other remaining groups and the groups 1, 2 and 3 showed satisfactory bond strength. The statistical evaluation also revealed that the bond strength of control group (37% phosphoric acid) was greater than those of experimental groups. Conclusion: The present study results shows that the ceramic brackets have higher bond strength than stainless steel brackets (material wise). PMID:25302260

Abinaya; Karthikeyan; Sarvanan; Vikram, Raj

2014-01-01

115

Surface characterization based upon significant topographic features  

NASA Astrophysics Data System (ADS)

Watershed segmentation and Wolf pruning, as defined in ISO 25178-2, allow the detection of significant features on surfaces and their characterization in terms of dimension, area, volume, curvature, shape or morphology. These new tools provide a robust way to specify functional surfaces.

Blanc, J.; Grime, D.; Blateyron, F.

2011-08-01

116

Point-Based Probabilistic Surfaces to Show Surface Uncertainty  

E-print Network

with uncertainties is an important topic with many applications in science and engineering. In these applications with which that location is known. Examples include environmental pollution borderline detection, oil basin uncertainty, point-based graphics. æ 1 INTRODUCTION EVERYTHING we measure in science and engineering can have

Rheingans, Penny

117

Study of the composition, structure, and optical properties of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket films erbium doped from the Er(pd){sub 3} complex compound  

SciTech Connect

Rutherford backscattering, IR spectroscopy, ellipsometry, and atomic-force microscopy are used to perform an integrated study of the composition, structure and optical properties of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films. The technique employed to obtain the a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films includes the high-frequency decomposition of a mixture of gases, (SiH{sub 4}){sub a} + (CH{sub 4}){sub b}, and the simultaneous thermal evaporation of a complex compound, Er(pd){sub 3}. It is demonstrated that raising the amount of CH{sub 4} in the gas mixture results in an increase in the carbon content of the films under study and an increase in the optical gap E{sub g}{sup opt} from 1.75 to 2.2 eV. Changes in the composition of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films, accompanied, in turn, by changes in the optical constants, are observed in the IR spectra. The ellipsometric spectra obtained are analyzed in terms of multiple-parameter models. The conclusion is made on the basis of this analysis that the experimental and calculated spectra coincide well when variation in the composition of the amorphous films with that of the gas mixture is taken into account. The existence of a thin (6-8 nm) silicon-oxide layer on the surface of the films under study and the validity of using the double-layer model in ellipsometric calculations is confirmed by the results of structural analyses by atomic-force microscopy.

Kudoyarova, V. Kh., E-mail: kudoyarova@mail.ioffe.ru; Tolmachev, V. A.; Gushchina, E. V. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-03-15

118

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

NASA Astrophysics Data System (ADS)

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).

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

2013-02-01

119

Influence of Tm:YAP laser irradiation on tensile strength for bracket debonding  

NASA Astrophysics Data System (ADS)

The investigation of tensile strength needed for bracket debonding was the aim of study. A diode pumped Tm: YAP microchip laser generating a continuous 2um radiation with the maximum output power of 4W was used for debonding purposes. The group of 60 brackets was debonded using classical and laser irradiation methods - the doze from 1W to 4 W, 60s. The tensile strength without laser irradiation was in the range from 39.6 N (full ceramic bracket group) to 63.7 N (ceramic bracket with metal slot group). After irradiation the tensile strength was decreased from 35.1 N (full ceramic bracket group) to 48.8 N (ceramic bracket with metal slot group). The results of our study generally agree with the previous studies, substantiating the fact that lasers can be used effectively to thermally soften the adhesive resin for removal of ceramic brackets. From the practical point of view is conclusion that during laser irradiation, thermal ablation occurs and the bracket is removed from the enamel together with the rest of the adhesive resin. Laser debonding is easier and little heat diffusion occurred.

Dostalova, Tatjana; Jelinkova, Helena; Sulc, Jan; Koranda, Petr; Nemec, Michal; Fibrich, Martin; Jelinek, Michal; Michalik, Pavel; Miyagi, Mitsunobu

2011-03-01

120

Friction Forces during Sliding of Various Brackets for Malaligned Teeth: An In Vitro Study  

PubMed Central

Aims. To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3) and low-friction (Synergy) brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine. Methods. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA) was carried out to investigate whether the following factors affect the values of friction force: (i) degree of malalignment, (ii) diameter of the orthodontic wire, and (iii) bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed. Results. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments. Conclusion. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance. PMID:23533364

Crincoli, Vito; Di Bisceglie, Maria Beatrice; Balsamo, Antonio; Serpico, Vitaliano; Chiatante, Francesco; Pappalettere, Carmine; Boccaccio, Antonio

2013-01-01

121

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

PubMed Central

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

Sungurtekin Ekci, Elif; Sandalli, Nuket

2014-01-01

122

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

PubMed Central

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

Contreras-Bulnes, Rosalia; Scougall-Vilchis, Rogelio J.; Rodriguez-Vilchis, Laura E.; Centeno-Pedraza, Claudia; Olea-Mejia, Oscar F.; Alcantara-Galena, Maria del Carmen Z.

2013-01-01

123

Speech interfaces based upon surface electromyography  

Microsoft Academic Search

This paper discusses the use of surface electromyography (EMG) to recognize and synthesize speech. The acoustic speech signal can be significantly corrupted by high noise in the environment or impeded by garments or masks. Such situations occur, for example, when firefighters wear pressurized suits with self-contained breathing apparatus (SCBA) or when astronauts perform operations in pressurized gear. In these conditions

Charles Jorgensen; Sorin Dusan

2010-01-01

124

Correction of Longitudinal Epiphyseal Bracket Disease with External Fixation: A Case Report with 6-year Follow-up Period  

Microsoft Academic Search

Longitudinal epiphyseal bracket disease is a rare congenital abnormality of the tubular bones. This syndrome eventually leads to progressive shortening and angular deformity of the involved bone. When longitudinal epiphyseal bracket disease affects the first metatarsal, a short trapezoidal shaped metatarsal is noted radiographically. We present the case of a 9-year-old patient with longitudinal epiphyseal bracket disease of the first

Ryan T. Scott; Charles Kissel; Amy Miller

2011-01-01

125

TOWARDS SPEAKER-ADAPTIVE SPEECH RECOGNITION BASED ON SURFACE ELECTROMYOGRAPHY  

E-print Network

is called surface elec- tromyography, however we use the abbreviation EMG for simplicity. #12;sted, 2005TOWARDS SPEAKER-ADAPTIVE SPEECH RECOGNITION BASED ON SURFACE ELECTROMYOGRAPHY Michael Wand that capture the movements of the human articulatory muscles at the skin surface for recognizing continuously

Schultz, Tanja

126

LIQUID SIMULATION WITH MESH-BASED SURFACE TRACKING  

E-print Network

LIQUID SIMULATION WITH MESH-BASED SURFACE TRACKING Siggraph 2011 Course Notes Half Day Course Columbia #12;Course Description Animating detailed liquid surfaces has continually been a challenge extremely detailed liquid surfaces as efficiently as possible. This course will provide attendees

Teschner, Matthias

127

Surface characterization based on optical phase shifting interferometry  

DOEpatents

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.

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

2011-08-02

128

Nanoparticle-based etching of silicon surfaces  

DOEpatents

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.

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

129

Surface-Based and Probabilistic Atlases of Primate Cerebral Cortex  

E-print Network

Neuron Primer Surface-Based and Probabilistic Atlases of Primate Cerebral Cortex David C. Van Essen. For studies of cerebral cortex there is particular utility in hybrid atlases that capitalize focuses on surface-based atlases of cerebral cortex in primates, especially humans. Cerebral cortex

Van Essen, David

130

Surface-scribed transparency-based microplates.  

PubMed

Transparency sheets, which are normally associated with use on overhead projectors, offer lowered costs and high amenability for optical diagnostics in microplate instrumentation. An alternative microplate design in which circles are scribed on the surface of the transparency to create the boundaries to hold the drop in place is investigated here. The 3D profile of the scribed regions obtained optically showed strong likelihood of affecting three-phase contact line interactions. During dispensation, the contact angle (?95°) was larger than the drop advancing state (?80°) due to a period of nonadhesion, where the contact angle later reduced to the drop advancing state followed by increase in the liquid area coverage on the substrate. It was established that 50 ?L was needed to fill the well fully, and the maximum volume retainable before breaching was 190 ?L. While the tilt angle needed for displacement reduced significantly from 50 to 95 ?L, this was markedly better than nonscribed surfaces, where tilt angles always had to be kept to within 30°. It was found that there was greater ability to fill the well with smaller volumes with dispensation at the center. This was attributed to the growing contact line not meeting the scribed edge in parallel if liquid was dispensed closer to it, wherein pinning reduction in some directions permitted liquid travel along the scribed edge to undergo contact angle hysteresis. Fluorescence measurements conducted showed no performance compromise when using scribed transparency microplates over standard microplates. PMID:23215012

Li, Xin Ye; Cheong, Brandon Huey-Ping; Somers, Anthony; Liew, Oi Wah; Ng, Tuck Wah

2013-01-15

131

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

USGS Publications Warehouse

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.

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

2007-01-01

132

Sea Surface Altimetry Based on Airborne Gnss Signal Measurements  

NASA Astrophysics Data System (ADS)

In this study the focus is on ocean surface altimetry using the signals transmitted from GNSS (Global Navigation Satellite System) satellites. A low-altitude airborne experiment was recently conducted off the coast of Sydney. Both a LiDAR experiment and a GNSS reflectometry (GNSS-R) experiment were carried out in the same aircraft, at the same time, in the presence of strong wind and rather high wave height. The sea surface characteristics, including the surface height, were derived from processing the LiDAR data. A two-loop iterative method is proposed to calculate sea surface height using the relative delay between the direct and the reflected GNSS signals. The preliminary results indicate that the results obtained from the GNSS-based surface altimetry deviate from the LiDAR-based results significantly. Identification of the error sources and mitigation of the errors are needed to achieve better surface height estimation performance using GNSS signals.

Yu, K.; Rizos, C.; Dempster, A.

2012-07-01

133

Deformation-based surface morphometry applied to gray matter deformation  

Microsoft Academic Search

We present a unified statistical approach to deformation-based morphometry applied to the cortical surface. The cerebral cortex has the topology of a 2D highly convoluted sheet. As the brain develops over time, the cortical surface area, thickness, curvature, and total gray matter volume change. It is highly likely that such age-related surface changes are not uniform. By measuring how such

Moo K. Chung; Keith J. Worsley; Steven M. Robbins; Tomas Paus; Jonathan E. Taylor; Jay N. Giedd; Judith L. Rapoport; Alan C. Evans

2003-01-01

134

Acceleration of surface-based hybridization reactions using isotachophoretic focusing.  

PubMed

We present a theoretical model and experimental demonstration of a novel method for acceleration of surface-based reactions using isotachophoresis (ITP). We use ITP to focus a sample of interest and deliver a high concentration target to a prefunctionalized surface, thus enabling rapid reaction at the sensor site. The concentration of the focused analyte is bound in space by the ITP interface and, upon reaction with the surface, continues electromigrating downstream, removing any contamination or reacted sample molecules from the surface. This constitutes a one-step react-and-wash assay which can be performed in a simple channel and does not require flow control elements or moving parts. We designed a novel microfluidic chip where reaction surfaces are formed by paramagnetic beads, immobilized at desired sites by an external magnetic field. Using this chip, we compared ITP-based surface hybridization to standard continuous flow-based hybridization and experimentally demonstrated a 2 orders of magnitude improvement in limit of detection (LoD) in a 3 min nucleic acid hybridization assay. The simple analytical model we present allows prediction of the rate of surface reaction under ITP and can be used to design and optimize such assays as a function of the physical properties of the system, including buffer chemistry, applied voltage, analyte mobility, analyte concentration, probe density, and surface length. The method, model, and experimental setup can be applied to various forms or surface reactions and may serve as the basis for highly genetic analysis and immunoassays. PMID:24517175

Karsenty, Merav; Rubin, Shimon; Bercovici, Moran

2014-03-18

135

GPU-based Collision Detection for Deformable Parameterized Surfaces  

Microsoft Academic Search

Based on the potential of current programmable GPUs, recently several approaches were developed that use the GPU to calculate deformations of surfaces like the folding of cloth or to convert higher level geometry to renderable primitives like NURBS or subdivision surfaces. These algorithms are realized as a per-frame operation and take advantage of the parallel processing power of the GPU.

Alexander Greß; Michael Guthe; Reinhard Klein

2006-01-01

136

High sensitivity surface plasmon resonace sensor based on phase detection  

Microsoft Academic Search

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

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

1996-01-01

137

FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS  

E-print Network

FEATURE BASED HANDLING OF SURFACE FAULTS IN COMPACT DISC PLAYERS Peter Fogh Odgaard ,1 Jakob & Olufsen A/S, Peter Bangs Vej 15, DK-7600 Struer, Denmark Abstract: Compact Disc players have been. However, there are still problems with playing Compact Discs related to surface faults like scratches

Wickerhauser, M. Victor

138

Image-based multiresolution shape recovery by surface deformation  

Microsoft Academic Search

This paper presents a novel approach for constructing multiresolution surface models from a set of calibrated images. The output is a texture-mapped triangular surface mesh that best matches all the input images. The mesh is obtained by deforming a generic initial mesh such as a sphere or cube according to image and geometry-based forces. This technique has the following key

Li Zhang; Steven M. Seitz

2000-01-01

139

(p + 1)-Algebra for a super p-brane: the Nambu bracket reformulation  

SciTech Connect

We express the covariant actions of a super p-brane and the corresponding equations of motion, in flat and curved superspaces, in terms of the Nambu (p + 1)-brackets. These brackets make the (p + 1)-algebra structure of a super p-brane manifest. For the flat superspace, this reconstruction of the action also allows reformulating it in terms of two sets of differential forms.

Kamani, D., E-mail: kamani@aut.ac.ir [Amirkabir University of Technology (Tehran Polytechnic), Physics Department (Iran, Islamic Republic of)

2011-05-15

140

Galvanic corrosion between orthodontic wires and brackets in fl uoride mouthwashes  

Microsoft Academic Search

SUMMARY The aim of this investigation was to determine the infl uence of fl uoride in certain mouthwashes on the risk of corrosion through galvanic coupling of orthodontic wires and brackets. Two titanium alloy wires, nickel-titanium (NiTi) and copper-nickel-titanium (CuNiTi), and the three most commonly used brackets, titanium (Ti), iron-chromium-nickel (FeCrNi) and cobalt-chromium (CoCr), were tested in a reference solution

Nicolas Schiff; Mickaël Boinet; Laurent Morgon; Michèle Lissac; Francis Dalard; Brigitte Grosgogeat

2006-01-01

141

Virtual walls based on oil-repellent surfaces for low-surface-tension liquids.  

PubMed

Manipulating and controlling water-based aqueous solutions with the use of virtual walls is relatively simple compared to that of nonaqueous low-surface-tension liquids, which pose greater challenges to microfluidic devices. This letter reports a novel technique to form a virtual wall for various low-surface-tension liquids. A microfluidic channel with virtual walls has been made to guide low-surface-tension liquids by using a specially designed oil-repellent surface. Unlike generic superoleophobic surfaces, our oil-repellent surface exhibited strong repellency to the lateral flow of low-surface-tension liquids such as hexadecane and dodecane. A plasma-assisted surface micromachining process has been utilized to form the oil-repellent surface. The use of combined features of re-entrant geometries on the surface played an important role in promoting its repellence to the lateral flow of low-surface-tension liquids. We have successfully demonstrated how low-surface-tension liquids can be well confined by the virtual walls. PMID:23311883

Almeida, Riberet; Kwon, Jae Wan

2013-01-29

142

Comparative Evaluation of Shear Bond Strength of Recycled Brackets using Different Methods: An In vitro Study  

PubMed Central

Background: Debonding of brackets commonly occurs during orthodontic treatment. Due to increase in costs replacement of a damaged bracket is not liked by the dentist. This study is done to assess the shear bond strength of recycled brackets using different methods. Materials and Methods: This study was conducted using five groups of orthodontic brackets (0.022” × 0.028”, MBT prescription) bonded on the premolars mounted in cubes. Other materials required were cubical trays, bonding material, light cure unit, universal testing machine, digital camera and sandblasting unit. Results: From the result of ANOVA test we observed the test is significant (F = 20.79, P < 0.01) and the test is rejected. When the Tukey’s t-test result was applied it was seen that the mean shear bond strength of all groups of brackets is as follows: Group I (5.31 Megapascals [Mpa]) < Group II (7.37 Mpa) < Group III (8.96 Mpa) < Group IV (5.56 Mpa) < Control group (9.24 Mpa). Alternatively we can say that shear bond strength of following bracket groups can be arranged as Group I < Group IV < Group II < Group III. Conclusion: From this study we conclude that Group III, which was recycled with an ultrasonic cleaner with electropolisher and silane coupling agent in place of primer, showed the highest shear bond strength.

Kumar, Mukesh; Maheshwari, Amit; Lall, Rajeev; Navit, Pragati; Singh, Rajeshwar; Navit, S

2014-01-01

143

Effect of moisture, saliva, and blood contamination on the shear bond strength of brackets bonded with a conventional bonding system and self-etched bonding system  

PubMed Central

Background: The success of bonding brackets to enamel with resin bonding systems is negatively affected by contamination with oral fluids such as blood and saliva. The new self-etch primer systems combine conditioning and priming agents into a single application, making the procedure more cost effective. Objective: The purpose of the study was to investigate the effect of moisture, saliva and blood contamination on shear bond strength of orthodontic brackets bonded with conventional bonding system and self-etch bonding system. Materials and Methods: Each system was examined under four enamel surface conditions (dry, water, saliva, and blood), and 80 human teeth were divided into two groups with four subgroups each of 10 according to enamel surface condition. Group 1 used conventional bonding system and Group 2 used self-etched bonding system. Subgroups 1a and 2a under dry enamel surface conditions; Subgroups 1b and 2b under moist enamel surface condition; Subgroups 3a and 3b under saliva enamel surface condition and Subgroup 4a and 4b under blood enamel surface condition. Brackets were bonded, and all the samples were then submitted to a shear bond test with a universal testing machine with a cross head speed of 1mm/sec. Results: The results showed that the contamination reduced the shear bond strength of all groups. In self-etch bonding system water and saliva had significantly higher bond strength when compared to other groups. Conclusion: It was concluded that the blood contamination showed lowest bond strength from both bonding systems. Self-etch bonding system resulted in higher bond strength than conventional bonding system under all conditions except the dry enamel surface. PMID:24678210

Prasad, Mandava; Mohamed, Shamil; Nayak, Krishna; Shetty, Sharath Kumar; Talapaneni, Ashok Kumar

2014-01-01

144

Multiresolution parameterization of meshes for improved surface-based registration  

NASA Astrophysics Data System (ADS)

Common problems in medical image analysis involve surface-based registration. The applications range from atlas matching to tracking an object's boundary in an image sequence, or segmenting anatomical structures out of images. Most proposed solutions are based on deformable surface algorithms. The main problem of such methods is that the local accuracy of the matching must often be traded off against global smoothness of the surface in order to reach global convergence of the deformation process. Our contribution is to first build a Multi-Resolution (M-R) surface from a reference segmented image, and then match this surface onto the target image in an M-R fashion using a deformable surface-like algorithm. As we proceed from lower to higher resolution, the smoothing effect of the deformable surface is more and more localized, and the surface gets closer and closer to the target boundary. We present initial results of our algorithm for atlas registration onto brain MRI showing improved convergence and accuracy over classical deformable surface methods.

Jaume, Sylvain; Ferrant, Matthieu; Warfield, Simon K.; Macq, Benoit M. M.

2001-07-01

145

Design of Surfaces for Liquid Crystal-Based Bioanalytical Assays  

PubMed Central

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

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

2010-01-01

146

Reconstructing Surfaces of Particle-Based Fluids Using Anisotropic Kernels  

E-print Network

Hydrodynamics (SPH) is the most popular approach for simulating fluid since it is computationally si reconstruction method for particle- based fluid simulators such as smoothed particle hydrodynamics. In particle- based simulations, fluid surfaces are usually defined as a level set of an implicit function. We

Turk, Greg

147

Multivariate Statistics of Tensor-Based Cortical Surface Morphometry  

E-print Network

Jacobian matrix based statistics. Subjects · 80 subjects had 1.5 T 3D T1-weighted brain MRIs (a methods based on simpler univariate surface measures. Full Matrix J Determina nt of J Largest EV of J Pair, and the National Institute for Child Health and Development (EB01651, RR019771, HD050735, AG016570, LM05639 to P

Wang, Yalin

148

Interactions between acid- and base-functionalized surfaces.  

PubMed

In this paper we present an AFM force study on interactions between chemically modified surfaces. Surfaces with terminal groups of either NH(2) or COOH were obtained by chemisorption of a silane-based compound (3-amino-propyltriethoxysilane) on silica or a thiol compound (11-mercapto undecanoic acid) on gold. The surfaces were characterized by streaming potential and contact angle measurements. For the NH(2) surfaces the density of functional groups strongly depends on the pretreatment of the silica. Both the NH(2) and COOH surfaces show a steady and ongoing loss of functional groups, but on the time scale of our force measurements they can be considered to be stable. Interaction curves for the various combinations of surfaces in aqueous solutions show a strong correlation with the ionization state of the surface groups. The approach curves can be explained on the basis of electrostatic interactions. On retraction a pH-dependent adhesion is found, the strongest being between NH(2) and COOH surfaces as a result of acid-base interactions. Between NH(2) layers and between COOH layers there is also adhesion, due to the formation of H bonds. The corresponding work of adhesion W was calculated using the DMT (Derjaguin, Muller, Toporov) equation. The values of W obtained are small compared to literature data and suggest that only a fraction of the functional groups in the contact area is involved in acid-base or H-bond interactions. This is attributed mainly to the roughness of the surfaces, which substantially reduces adhesion. A rough estimate is made for the rupture force of the NH(2)-COOH acid-base bond in water. PMID:16290772

Giesbers, Marcel; Kleijn, J Mieke; Cohen Stuart, Martien A

2002-08-01

149

Mechanically robust superhydrophobic polymer surfaces based on protective micropillars.  

PubMed

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

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

2014-02-11

150

Effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cements.  

PubMed

The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups. PMID:22379131

Pereira, Tatiana Bahia Junqueira; Jansen, Wellington Corrêa; Pithon, Matheus Melo; Souki, Bernardo Quiroga; Tanaka, Orlando Motohiro; Oliveira, Dauro Douglas

2013-08-01

151

Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.  

PubMed

In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers. PMID:23572003

Andryieuski, Andrei; Lavrinenko, Andrei V

2013-04-01

152

Surface and pseudo-surface acoustic waves piezoelectrically excited in diamond-based structures  

NASA Astrophysics Data System (ADS)

Surface and pseudo-surface acoustic plane waves generated in two- and three-layer AlN/Diamond and AlN/Diamond/? -TiAl structures by a point electric source are analyzed in the mathematical framework based on the Green's matrix integral representation and guided wave asymptotics derived using the residue technique. The attention is focused on the effect of pseudo-surface-to-surface wave degeneration at certain discrete values of h /? (h is the thickness of the piezoelectric layer and ? is the wave-length). Earlier such optimal ratios were discovered and experimentally verified for the first pseudo-surface (Sezawa) wave mode in the AlN/Diamond structure. The present research reveals this effect for higher modes as well as examines its manifestation for three-layer structures with different diamond-to-AlN thickness ratios H/h.

Glushkov, Evgeny; Glushkova, Natalia; Zhang, Chuanzeng

2012-09-01

153

Silicon-based surface plasmon resonance combined with surface-enhanced Raman scattering for chemical sensing  

Microsoft Academic Search

A Si-based surface plasmon resonance (SPR) technique has been successfully applied to NO2 sensing at ppm level, with estimated detectability at less than 100 ppb. Surface-enhanced Raman scattering (SERS) has been used in this scheme as an inherent additional data acquisition channel capable of providing spectroscopic selectivity and amplified sensitivity. The behavior of both the SERS spectrum and the SPR-induced

P. I. Nikitin; A. A. Beloglazov; M. V. Valeiko; J. A. Creighton; J. D. Wright

1997-01-01

154

Wavelet-based detection of clods on a soil surface  

NASA Astrophysics Data System (ADS)

One of the aims of the tillage operation is to produce a specific range of clod sizes, suitable for plant emergence. Due to its cloddy structure, a tilled soil surface has its own roughness, which is connected also with soil water content and erosion phenomena. The comprehension and modeling of surface runoff and erosion require that the micro-topography of the soil surface is well estimated. Therefore, the present paper focuses on the soil surface analysis and characterization. An original method consisting in detecting the individual clods or large aggregates on a 3D digital elevation model (DEM) of the soil surface is introduced. A multiresolution decomposition of the surface is performed by wavelet transform. Then a supervised local maxima extraction is performed on the different sub surfaces and a last process makes the validation of the extractions and the merging of the different scales. The method of detection was evaluated with the help of a soil scientist on a controlled surface made in the laboratory as well as on real seedbed and ploughed surfaces, made by tillage operations in an agricultural field. The identifications of the clods are in good agreement, with an overall sensitivity of 84% and a specificity of 94%. The false positive or false negative detections may have several causes. Some very nearby clods may have been smoothed together in the approximation process. Other clods may be embedded into another peace of the surface relief such as another bigger clod or a part of the furrow. At last, the low levels of decomposition are dependent on the resolution and the measurement noise of the DEM. Therefore, some borders of clods may be difficult to determine. The wavelet-based detection method seems to be suitable for soil surfaces described by 2 or 3 levels of approximation such as seedbeds.

Vannier, E.; Ciarletti, V.; Darboux, F.

2009-11-01

155

Surface activation-based nanobonding and interconnection at room temperature  

NASA Astrophysics Data System (ADS)

Flip chip nanobonding and interconnect system (NBIS) equipment with high precision alignment has been developed based on the surface activated bonding method for high-density interconnection and MEMS packaging. The 3? alignment accuracy in the IR transmission system was approximately ±0.2 µm. The performance of the NBIS has been preliminarily investigated through bonding between relatively rough surfaces of copper through silicon vias (Cu-TSVs) and gold-stud bumps (Au-SBs), and smooth surfaces of silicon wafers. The Cu-TSVs of 55 µm diameter and the Au-SBs of 35 µm diameter with ~6-10 nm surface roughness (RMS) were bonded at room temperature after surface activation using an argon fast atom beam (Ar-FAB) under 0.16 N per bump. Silicon wafers of 50 mm diameter with ~0.2 nm RMS surface roughness were bonded without heating after surface activation. Void-free interfaces both in Cu-TSV/Au-SB and silicon/silicon with bonding strength equivalent to bulk fracture of Au and silicon, respectively, were achieved. A few nm thick amorphous layers were observed across the silicon/silicon interface that was fabricated by the Ar-FAB. This study in the interconnection and bonding facilitates the required three-dimensional integration on the same surface for high-density electronic and biomedical systems.

Howlader, M. M. R.; Yamauchi, A.; Suga, T.

2011-02-01

156

The Effect on Final Bond Strength of Bracket Manipulation Subsequent To Initial Positioning  

NASA Astrophysics Data System (ADS)

The shear bond strength of light activated orthodontic adhesives varies according to the composition of the material, placement protocol, and time prior to light curing. Manipulating brackets after their initial placement on a tooth can disrupt the adhesive's polymerization and compromise final bond strength. No previous research has investigated how a specific degree of manipulation, and the amount of time elapsed prior to curing, under specific lighting conditions, affects the orthodontic adhesives shear bond strength. Victory SeriesRTM, MBT prescription, premolar (3M Unitek, Monrovia, CA) orthodontic brackets were bonded using three different adhesives to sixty (60) bicuspids and varying the time after bracket manipulation before curing. The shear bond strength was calculated for each specimen. The brackets were debonded and the same teeth were rebonded with new, identical brackets, using the same protocol and under the same conditions. The results showed a statistically significant difference between the shear bond strength of Transbond XT and Grengloo, with Transbond XT having the highest strength. There was also a statistically significance difference in bond strength between the group cured 30 seconds after manipulation and the groups manipulated at different intervals prior to curing, with the 30 second group having the highest bond strength. This study confirms that various orthodontic adhesives have different bond strengths depending on manipulation and varying times prior to curing each adhesive.

Beebe, David A.

157

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

PubMed Central

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

Mansor, Noorhanizar; Saub, Roslan

2014-01-01

158

Chemical sensors based on surface-confined dendrimers  

SciTech Connect

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.

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

159

Controllable adhesive superhydrophobic surfaces based on PDMS microwell arrays.  

PubMed

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

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

2013-03-12

160

A surface coordination network based on copper adatom trimers.  

PubMed

Surface coordination networks formed by co-adsorption of metal atoms and organic ligands have interesting properties, for example regarding catalysis and data storage. Surface coordination networks studied to date have typically been based on single metal atom centers. The formation of a novel surface coordination network is now demonstrated that is based on network nodes in the form of clusters consisting of three Cu adatoms. The network forms by deposition of tetrahydroxybenzene (THB) on Cu(111) under UHV conditions. As shown from a combination of scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations, all four hydroxy groups of THB dehydrogenate upon thermal activation at 440?K. This highly reactive ligand binds to Cu adatom trimers, which are resolved by high-resolution STM. The network creates an ordered array of mono-dispersed metal clusters constituting a two-dimensional analogue of metal-organic frameworks. PMID:25251167

Bebensee, Fabian; Svane, Katrine; Bombis, Christian; Masini, Federico; Klyatskaya, Svetlana; Besenbacher, Flemming; Ruben, Mario; Hammer, Bjørk; Linderoth, Trolle R

2014-11-17

161

Three-Dimensional Surface Mesh Segmentation Using Curvedness-Based  

E-print Network

Three-Dimensional Surface Mesh Segmentation Using Curvedness-Based Region Growing Approach Anupama THREE-DIMENSIONAL mesh segmentation refers to the pro- blem of partitioning a given 3D triangular mesh objects, which in turn are generated by range sensors [4]. Examples of applications that benefit from mesh

Miller, Eric

162

Frontiers in surface-based microwave and millimeter wavelength radiometry  

Microsoft Academic Search

Surface-based radiometric sensing of atmospheric parameters has a long history of providing useful measurements of temperature, water vapor, and cloud liquid. In this Special Tributary Session to Professor Calvin Swift, several contemporary instruments are discussed and representative results are presented. Recent and promising developments include new absorption models, improved retrieval techniques, multifrequency radiometers, scanning observations of clouds, and combined active-passive

Ed R. Westwater; Susanne Crewell; Christian Mätzler

2004-01-01

163

Culturally based design: embodying trans-surface interaction in rummy  

Microsoft Academic Search

We present culturally based design (CBD), a new paradigm for designing embodied natural user interaction (NUI) with digital information by drawing on customary ways that people use physical objects. CBD coalesces experiences, practices, and embodied mental models of pre-digital activities as a basis for the design of interactive systems. We apply CBD to address trans-surface interaction, the manipulation of information

Andruid Kerne; William A. Hamilton; Zachary O. Toups

2012-01-01

164

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

NASA Astrophysics Data System (ADS)

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.

Balseiro, Paula

2014-11-01

165

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

PubMed Central

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

Liu, Jiansheng; Lu, Yanyan

2014-01-01

166

Silicon-based surface plasmon resonance combined with surface-enhanced Raman scattering for chemical sensing  

NASA Astrophysics Data System (ADS)

A Si-based surface plasmon resonance (SPR) technique has been successfully applied to NO2 sensing at ppm level, with estimated detectability at less than 100 ppb. Surface-enhanced Raman scattering (SERS) has been used in this scheme as an inherent additional data acquisition channel capable of providing spectroscopic selectivity and amplified sensitivity. The behavior of both the SERS spectrum and the SPR-induced photosignal produced by Au-on-Si grating structures coated with thin 18-crown-6 metal-free phthalocyanine films was simultaneously recorded for exposure of the films to 10 ppm of NO2 in air and its reversal in clean air. Both responses have been found to be reversible. The combination of Si-based SPR and SERS looks promising for thin-film and surface explorations, both in fundamental and sensor applications.

Nikitin, P. I.; Beloglazov, A. A.; Valeiko, M. V.; Creighton, J. A.; Wright, J. D.

1997-06-01

167

Topographic Surface-Based Modeling: Building Complex Stratigraphy with Geomorphic Surfaces  

NASA Astrophysics Data System (ADS)

Most three-dimensional geological models built using geostatistical techniques honor well data without difficulty, but fail to achieve geological realism. More often than not, model grids do not capture the stratigraphic complexity present in many depositional settings, and do not follow the actual layering in the sedimentary record, in particular where there are local volumes of steeper dips in channelized environments. Adding to the variety of surface-based modeling techniques that have been developed during the last decade, here we discuss 'topographic surface-based modeling': modeling approaches that build stratigraphy through reproducing the evolution of topographic surfaces over time. The topographies are derived from a variety of sources, including numerical forward modeling, present-day topography and bathymetry, outcrop data, and three-dimensional seismic reflection data. Whenever deposition and erosion occur at the same time, in a spatially predictable pattern (as it is often the case with instability-related morphodynamics, e.g., bedforms, meandering rivers, submarine channels), erosional surfaces are time-transgressive and can have complicated 3D geometries. These complexities are difficult to represent in object-based or voxel-based stochastic models but are easily captured in topographic surface-based models. As locations of deposition, nondeposition, and erosion are recorded for each time step, it is possible to build 3D Wheeler diagrams that show the space-time distribution of preserved and eroded sediment and the time-transgressive nature of erosional surfaces. 3D grids generated this way preserve significant stratigraphic detail without the need for a large number of grid cells. In addition, the topographic surfaces serve as inputs for realistic distribution of properties such as grain size, porosity, and permeability. For example, elevation above channel thalweg can be a proxy for property distribution in channelized settings. The methodology is applicable in modeling different depositional environments, especially in ones dominated by single-thread patterns of deposition and erosion. Examples include sinuous submarine slope channels, submarine lobe deposits, incised river valleys, and tidal inlets. These examples of topographic surface-based models show how the idea of translating geomorphology into stratigraphy has a number of useful applications.

Sylvester, Z.; Cantelli, A.; Howes, N. C.; Jobe, Z. R.; Wolinsky, M. A.; Pirmez, C.; Smith, R.

2012-12-01

168

Metallurgical characterization, galvanic corrosion, and ionic release of orthodontic brackets coupled with Ni-Ti archwires.  

PubMed

In orthodontics, a combination of metallic alloys is placed into the oral cavity during medical treatment and thus the corrosion resistance and ionic release of these appliances is of vital importance. The aim of this study is to investigate the elemental composition, microstructure, hardness, corrosion properties, and ionic release of commercially available orthodontic brackets and Copper Ni-Ti archwires. Following the assessment of the elemental composition of the orthodontic wire (Copper Ni-Ti) and the six different brackets (Micro Loc, Equilibrium, OptiMESH(XRT), Gemini, Orthos2, and Rematitan), cyclic polarization curves were obtained for each material to estimate the susceptibility of each alloy to pitting corrosion in 1M lactic acid. Galvanic corrosion between the orthodontic wire and each bracket took place in 1M lactic acid for 28 days at 37 degrees C and then the ionic concentration of Nickel and Chromium was studied. The orthodontic wire is made up from a Ni-Ti alloy with copper additions, while the orthodontic brackets are manufactured by different stainless steel grades or titanium alloys. All tested wires and brackets with the exception of Gemini are not susceptible to pitting corrosion. In galvanic corrosion, following exposure for 28 days, the lowest potential difference (approximately 250 mV) appears for the orthodontic wire Copper Ni-Ti and the bracket made up from pure titanium (Rematitan) or from the stainless steel AISI 316 grade (Micro Loc). Following completion of the galvanic corrosion experiments, measurable quantities of chromium and nickel ions were found in the residual lactic acid solution. PMID:16969817

Darabara, Myrsini S; Bourithis, Lefteris I; Zinelis, Spiros; Papadimitriou, George D

2007-04-01

169

Spectrometers for particle measurements in space based on surface reflection  

NASA Astrophysics Data System (ADS)

This is a review talk on space particle spectrometers based on the surface reflection technique. We sum up the experience in development and operation of such instruments accumulated for the last 15 years at the Swedish Institute of space Physics, Kiruna, Sweden in close cooperation with University of Bern, Bern, Switzerland. The technique is relatively new and used in space for measurements of few eV - few keV particles. It was first introduced for neutral atom detection in the GAS instrument onboard the ESA/NASA Ulysses mission (Witte et al., 1992) and later for ion measurements (Barabash et al., 2007) onboard Indian Chandrayaan-1. When a particle hit a surface, secondary electrons release and the particle is either absorbed by the surface or get scattered or reflected. The charge state of the reflected particles normally does not depend on the initial charge state and is neutral but also includes a fraction of negative and positive ions. These charged particles can be analyzed by conventional ion optics. The secondary electrons can be used for triggering a time-of-flight system. The surface reflection technique is close to the usage of foils/ulta-thin foils for particle detections but has a number of advantages. First, it does not require high pre-acceleration potentials and thus allows making more compact and light weight instruments. Secondly, it permits detection of neutral atoms down to 10 eV. Despite the interaction with the surface modifies the original particle velocity, the proper design of the following analyzer section and ion optics can mitigate this effect. We shortly introduce main characteristics of the particle - surface interactions important for this application, describe designs of the instruments flown in space, and show performances of the surface reflection based ENA and ion spectrometers developed for Mars / Venus Express, Chandrayaan-1, BepiColombo, Phobos-Grunt, and Swedish PRISMA.

Barabash, S.; Wieser, M.; Wurz, P.

2012-04-01

170

Material-based three-dimensional imaging with nanostructured surfaces  

NASA Astrophysics Data System (ADS)

Visualizing three-dimensional (3D) structures at the micrometer and nanometer scale is essential not only for characterizing materials and corrosion but also biological samples. Here, we present a material-based nano-optical method using the near-field properties of periodically nanostructured surfaces (photonic crystal slabs) to obtain 3D images. The wavelength and the quality factor of resonances in the transmission spectrum provide optical thickness information of objects on the surface, which we use for rapid topography determination of cells.

Nazirizadeh, Yousef; Reverey, Julia; Geyer, Ulf; Lemmer, Uli; Selhuber-Unkel, Christine; Gerken, Martina

2013-01-01

171

Photonic Crystal Biosensor Based on Optical Surface Waves  

PubMed Central

A label-free biosensor device based on registration of photonic crystal surface waves is described. Angular interrogation of the optical surface wave resonance is used to detect changes in the thickness of an adsorbed layer, while an additional simultaneous detection of the critical angle of total internal reflection provides independent data of the liquid refractive index. The abilities of the device are demonstrated by measuring of biotin molecule binding to a streptavidin monolayer, and by measuring association and dissociation kinetics of immunoglobulin G proteins. Additionally, deposition of PSS/PAH polyelectrolytes is recorded in situ resulting calculation of PSS and PAH monolayer thicknesses separately. PMID:23429517

Konopsky, Valery N.; Karakouz, Tanya; Alieva, Elena V.; Vicario, Chiara; Sekatskii, Sergey K.; Dietler, Giovanni

2013-01-01

172

A physically based model of global freshwater surface temperature  

NASA Astrophysics Data System (ADS)

Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through their tolerance to parasites and diseases. Models used to predict surface water temperature range between physically based deterministic models and statistical approaches. Here we present the initial results of a physically based deterministic model of global freshwater surface temperature. The model adds a surface water energy balance to river discharge modeled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff, and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by shortwave and longwave radiation and sensible and latent heat fluxes. Also included are ice formation and its effect on heat storage and river hydraulics. We use the coupled surface water and energy balance model to simulate global freshwater surface temperature at daily time steps with a spatial resolution of 0.5° on a regular grid for the period 1976-2000. We opt to parameterize the model with globally available data and apply it without calibration in order to preserve its physical basis with the outlook of evaluating the effects of atmospheric warming on freshwater surface temperature. We validate our simulation results with daily temperature data from rivers and lakes (U.S. Geological Survey (USGS), limited to the USA) and compare mean monthly temperatures with those recorded in the Global Environment Monitoring System (GEMS) data set. Results show that the model is able to capture the mean monthly surface temperature for the majority of the GEMS stations, while the interannual variability as derived from the USGS and NOAA data was captured reasonably well. Results are poorest for the Arctic rivers because the timing of ice breakup is predicted too late in the year due to the lack of including a mechanical breakup mechanism. Moreover, surface water temperatures for tropical rivers were overestimated, most likely due to an overestimation of rainfall temperature and incoming shortwave radiation. The spatiotemporal variation of water temperature reveals large temperature differences between water and atmosphere for the higher latitudes, while considerable lateral transport of heat can be observed for rivers crossing hydroclimatic zones, such as the Nile, the Mississippi, and the large rivers flowing to the Arctic. Overall, our model results show promise for future projection of global surface freshwater temperature under global change.

Beek, Ludovicus P. H.; Eikelboom, Tessa; Vliet, Michelle T. H.; Bierkens, Marc F. P.

2012-09-01

173

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 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...

2010-04-01

174

LINEAR FAMILY OF LIE BRACKETS ON THE SPACE OF MATRICES Mat(n m, K) AND ADO'S THEOREM  

E-print Network

LINEAR FAMILY OF LIE BRACKETS ON THE SPACE OF MATRICES Mat(n � m, K) AND ADO'S THEOREM B´ECHIR DALI Abstract. In this paper we classify a linear family of Lie brackets on the space of rectangular matrices representation of the (2n + 1)-dimensional Heisenberg Lie algebra Hn in a vector space V with dim V n+1. Finally

Paris-Sud XI, Université de

175

Optical Triangulation-Based Microtopographic Inspection of Surfaces  

PubMed Central

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

Costa, Manuel F. M.

2012-01-01

176

Modeling apple surface temperature dynamics based on weather data.  

PubMed

The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

2014-01-01

177

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

E-print Network

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 ...

Liu, Vincent Hok

2009-01-01

178

Lunar base surface mission operations. Lunar Base Systems Study (LBSS) task 4.1  

NASA Technical Reports Server (NTRS)

The purpose was to perform an analysis of the surface operations associated with a human-tended lunar base. Specifically, the study defined surface elements and developed mission manifests for a selected base scenario, determined the nature of surface operations associated with this scenario, generated a preliminary crew extravehicular and intravehicular activity (EVA/IVA) time resource schedule for conducting the missions, and proposed concepts for utilizing remotely operated equipment to perform repetitious or hazardous surface tasks. The operations analysis was performed on a 6 year period of human-tended lunar base operation prior to permanent occupancy. The baseline scenario was derived from a modified version of the civil needs database (CNDB) scenario. This scenario emphasizes achievement of a limited set of science and exploration objectives while emplacing the minimum habitability elements required for a permanent base.

1987-01-01

179

Miniature polarization analyzer based on surface plasmon polaritons  

NASA Astrophysics Data System (ADS)

We investigated a miniature plasmonic polarization analyzer measuring Stokes parameters of a light. The optical component consists of a 2 × 2 polarizer array, three linear polarizers, and one right-handed circular polarizer. These polarizers are formed with bull's eye structures on a metal surface. The measurements of Stokes parameters in a unit radius Poincaré sphere were demonstrated. Compact polarization-dependent optical sensing and imaging can be envisioned based on the miniature polarization analyzer.

Xie, Yu-Bo; Liu, Zheng-Yang; Wang, Qian-Jin; Zhu, Yong-Yuan; Zhang, Xue-Jin

2014-09-01

180

Acid–Base Properties of Aqueous Illite Surfaces  

Microsoft Academic Search

In this paper, the acid–base properties of illite\\/water suspensions are examined using the constant capacitance surface complexation model. On the basis of results of potentiometric titrations and solubility experiments, we conclude that the proton reactions in the supernatants of illite suspensions can be successfully represented by proton reactions of Al(H2O)63+and Si(OH)4in water solutions. For illustrating the acidic characteristics of aqueous

Qing Du; Zhongxi Sun; Willis Forsling; Hongxiao Tang

1997-01-01

181

Operational Satellite-based Surface Oil Analyses (Invited)  

Microsoft Academic Search

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

D. Streett; C. Warren

2010-01-01

182

Fourier-Based Inspection of Free-Form Reflective Surfaces  

Microsoft Academic Search

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

Y. Caulier; S. Bourennane

2008-01-01

183

On the Canonical Structure of the De Donder-Weyl Covariant Hamiltonian Formulation of Field Theory I. Graded Poisson brackets and equations of motion  

Microsoft Academic Search

The analogue of the Poisson bracket for the De Donder-Weyl (DW) Hamiltonian formulation of field theory is proposed. We start from the Hamilton- Poincar\\\\'{e}-Cartan (HPC) form of the multidimensional variational calculus and define the bracket on the differential forms over the space-time (=horizontal forms). This bracket is related to the Schouten-Nijenhuis bracket of the multivector fields which are associated with

Igor V. Kanatchikov; RWTH Aachen

1993-01-01

184

Minimizing the drawing stages of a Bracket Assembly Upper Spring using DYNAFORM  

Microsoft Academic Search

This research work deals with the formability of sheet metal parts that depends very much on material properties, machine and process parameters, and part geometry. It provides an insight into drawing of low carbon steel axis-symmetrical cylindrical cup known as Bracket Assembly Upper Spring using DYNAFORM in order to reduce the current four draw stages. The simulation process is analyzed

Farrahshaida Mohd Salleh; Izdihar Tharazi; Abdul Rahman Omar; Roseleena Jaafar; Wan Emri Wan Abdul Rahman

2011-01-01

185

The Bracketing Technique: A Method for Defining Administrative Needs and Priorities.  

ERIC Educational Resources Information Center

Bracketing is defined as a procedure whereby individual decisionmaking team members sharpen their perceptions of organizational need prior to administrative action. Like the Delphi technique, the procedure eliminates major detriments of group activity planning and includes sequential interrogations and feedback procedures. Unlike the Delphi…

LaBay, Michael J.; Peckenpaugh, Donald H.

186

The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.  

PubMed

The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching. PMID:21262931

Ozta?, E; Ba?delen, G; Kiliço?lu, H; Ulukapi, H; Aydin, I

2012-04-01

187

Comparison of shear bond strength of orthodontic brackets bonded with halogen and plasma arc light curing  

PubMed Central

Background: Reduced time and appropriate bond strength of brackets is one of the most important aspects of orthodontic treatments. Prolonged halogen light curing for bonding of brackets is undesirable, so the purpose of this study was to compare the shear bond strength of brackets bonded with halogen light and plasma arc system. Materials and Mehods: This was an experimental in vitro study. A total of 60 intact premolar teeth were collected and divided into four groups. Stainless steel orthodontic brackets were bonded to them. In groups 1 and 2, curing was done using halogen light given for 20 seconds from two and four angles. In groups 3 and 4, curing was carried out using the plasma arc system for 6 seconds from two and four angles. The shear bond strength was recorded by Instron. The statistics of ANOVA, Tukey's test, and T-test were used in data analysis. Results: There was a statistically significant difference in shear bond strength among the four groups (P = 0.043) and between group 1 with group 2 (P = 0.035). Yet, there was no statistically significant difference between brackets bonded with plasma arc and those bonded with halogen light or between the two groups of plasma arc. Conclusion: Using the plasma arc system is superior to other methods due to reduced curing time. Also, since in using the halogen light system, an increase in curing periods from different angles resulted in a significant increase in shear bond strength; it is advisable to apply the halogen light from different angles. PMID:23087739

Toodehzaeim, Mohammad Hossein; Kazemi, Alireza Danesh; Aghili, Hossein Agha; Barzegar, Kazem; Fallahtafti, Taranom

2012-01-01

188

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

PubMed

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(-1) 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

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

2014-03-01

189

Vitrified collagen-based conjunctival equivalent for ocular surface reconstruction.  

PubMed

The main functions of the conjunctiva, an essential part of the ocular surface, are to maintain the equilibrium of the tear film and to protect the eye. Upon injuries, the prerequisite to successful ocular surface repair is conjunctival reconstruction. Tissue engineering techniques, including transplantation of autografts, amniotic membranes and numerous synthetic/natural materials, have been developed. However, none of these strategies is completely satisfactory due to lack of goblet cell repopulation, poor mechanical properties or non-standardized preparation procedure. Here, we cultured conjunctival epithelial cells on vitrified collagen membranes and developed a tissue equivalent for repairing damaged conjunctiva. Optimized vitrified collagen has superior mechanical and optical properties to previous biomaterials for ocular surface application, and its unique fibrillar structure significantly benefited conjunctival epithelial cell growth and the phenotypic development in vitro. In a rabbit model, vitrified collagen greatly promoted conjunctival regeneration with rapid re-epithelization, sufficient repopulation of goblet cells and minimized fibrosis and wound contracture, proved by gene expression analyses and histological staining. In conclusion, we have demonstrated the potential suitability of utilizing vitrified collagen-based tissue equivalent in ocular surface reconstruction. PMID:24933512

Zhou, Huifang; Lu, Qiaozhi; Guo, Qiongyu; Chae, Jemin; Fan, Xianqun; Elisseeff, Jennifer H; Grant, Michael P

2014-08-01

190

Surface engineering of graphene-based nanomaterials for biomedical applications.  

PubMed

Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications. PMID:25117569

Shi, Sixiang; Chen, Feng; Ehlerding, Emily B; Cai, Weibo

2014-09-17

191

Acid-base properties of aqueous illite surfaces  

SciTech Connect

In this paper, the acid-base properties of illite/water suspensions are examined using the constant capacitance surface complexation model. On the basis of results of potentiometric titrations and solubility experiments, the authors conclude that the proton reactions in the supernatants of illite suspensions can be successfully represented by proton reactions of Al(H{sub 2}O){sub 6}{sup 3+} and Si(OH){sub 4} in water solutions. For illustrating the acidic characteristics of aqueous illite surfaces, two surface protonation models are proposed: (1) one site-one pK{sub a} model, {triple_bond}SOH {r_reversible} {triple_bond}SO{sup {minus}} + H{sup +}, pK{sub a}{sup int} = 4.12-4.23; (2) two sites-two pK{sub a}s model, {triple_bond}S{sub 1}OH {r_reversible} {triple_bond}S{sup 1}O{sup {minus}} + H{sup +}, pK{sub a{sub I}} = 4.17-4.44, and {triple_bond}S{sub II}OH {r_reversible} {triple_bond}S{sub II}O{sup {minus}} + H{sup +}, pK{sub a{sub II}}{sup int} = 6.35-7.74. Evaluation of these two models indicates that both of them can give good descriptions of the experimental data of systems with different illite concentrations and ionic strengths and that the one site-one pK{sub a} model can be considered as a simplification of the two sites-two pK{sub a}s model. Since both models assume only deprotonation reactions at the illite surfaces, they suggest that the surface behavior of the illite is similar to that of amorphous SiO{sub 2}. Model assumptions, experimental procedures, and evaluative criteria are detailed in the paper.

Du, Q. [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry] [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry; [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences; Sun, Z.; Forsling, W. [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry] [Luleaa Univ. of Technology (Sweden). Div. of Inorganic Chemistry; Tang, H. [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences] [Academia Sinica, Beijing (China). Research Center for Eco-Environmental Sciences

1997-03-01

192

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

193

An Ab Initio Based Potential Energy Surface for Water  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

194

Localized surface plasmon resonance of silver nanoisland based glucose sensor  

NASA Astrophysics Data System (ADS)

Study of optical properties of glucose is an attractive research topic for years. One of the goals is to develop a portable device for simple, reliable, cost effective and non-invasive monitoring of glucose in blood for diabetics. In this work, we study localized surface plasmon resonance (LSPR) of Ag nanoisland based glucose sensor. The progressive shift in LSPR caused by the various concentration of glucose from 2M to 10M has been investigated to monitor the sensing property. We correlate the redshift of LSPR is due to the change in refractive index of surrounding glucose medium. Preliminary results show that this may possibly reveal a new pathway for sensing glucose.

Venugopal, N.; Mitra, Anirban

2013-06-01

195

Progress report: probabilistic and statistical bases of surface brightness fluctuations  

E-print Network

The surface brightness fluctuations (SBF) method is a statistical method applied on image pixels in different bands. This contribution aims to distinguish between the observational (statistical) method and the theoretical (probabilistic) method based on stellar population synthesis and needed for the calibration of observational SBF. We find that the commonly used SBF theoretical definition as the "mean luminosity-weighted luminosity of the stellar population" is only compatible with the observational method under quite strong hypotheses, and that it is not compatible with stellar population theory results.

M. Cervino; V. Luridiana; L. Jamet

2006-12-18

196

Spatial resolution in prism-based surface plasmon resonance microscopy.  

PubMed

Several optical surface sensing techniques, such as Surface Plasmon Resonance (SPR), work by imaging the base of a prism by one of its faces. However, such a fundamental optical concern has not been fully analyzed and understood so far, and spatial resolution remains a critical and controversial issue. In SPR, the propagation length Lx of the surface plasmon waves has been considered as the limiting factor. Here, we demonstrate that for unoptimized systems geometrical aberrations caused by the prism can be more limiting than the propagation length. By combining line-scan imaging mode with optimized prisms, we access the ultimate lateral resolution which is diffraction-limited by the object light diffusion. We describe several optimized configurations in water and discuss the trade-off between Lx and sensitivity. The improvement of resolution is confirmed by imaging micro-structured PDMS stamps and individual living eukaryote cells and bacteria on field-of-view from 0.1 to 20 mm2. PMID:25321746

Laplatine, Loïc; Leroy, Loïc; Calemczuk, Roberto; Baganizi, Dieudonné; Marche, Patrice N; Roupioz, Yoann; Livache, Thierry

2014-09-22

197

Multiresolution mesh segmentation based on surface roughness and wavelet analysis  

NASA Astrophysics Data System (ADS)

During the last decades, the three-dimensional objects have begun to compete with traditional multimedia (images, sounds and videos) and have been used by more and more applications. The common model used to represent them is a surfacic mesh due to its intrinsic simplicity and efficacity. In this paper, we present a new algorithm for the segmentation of semi-regular triangle meshes, via multiresolution analysis. Our method uses several measures which reflect the roughness of the surface for all meshes resulting from the decomposition of the initial model into different fine-to-coarse multiresolution meshes. The geometric data decomposition is based on the lifting scheme. Using that formulation, we have compared various interpolant prediction operators, associated or not with an update step. For each resolution level, the resulting approximation mesh is then partitioned into classes having almost constant roughness thanks to a clustering algorithm. Resulting classes gather regions having the same visual appearance in term of roughness. The last step consists in decomposing the mesh into connex groups of triangles using region growing ang merging algorithms. These connex surface patches are of particular interest for adaptive mesh compression, visualisation, indexation or watermarking.

Roudet, Céline; Dupont, Florent; Baskurt, Atilla

2007-01-01

198

Remote surface water monitoring radio based telemetry system  

NASA Astrophysics Data System (ADS)

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.

Goodwin, W. L.; Baxter, D.

1993-02-01

199

Osteoconductive Protamine-based Polyelectrolyte Multilayer Functionalized Surfaces  

PubMed Central

The integration of orthopedic implants with host bone presents a major challenge in joint arthroplasty, spinal fusion and tumor reconstruction. The cellular microenvironment can be programmed via implant surface functionalization allowing direct modulation of osteoblast adhesion, proliferation, and differentiation at the implant-bone interface. The development of layer-by-layer assembled polyelectrolyte multilayer (PEM) architectures has greatly expanded our ability to fabricate intricate nanometer to micron scale thin film coatings that conform to complex implant geometries. The in vivo therapeutic efficacy of thin PEM implant coatings for numerous biomedical applications has previously been reported. We have fabricated protamine-based PEM thin films that support the long-term proliferation and differentiation of pre-osteoblast cells on non-cross-linked film coated surfaces. These hydrophilic PEM functionalized surfaces with nanometer-scale roughness facilitated increased deposition of calcified matrix by osteoblasts in vitro, and thus offer the potential to enhance implant integration with host bone. The coatings can make an immediate impact in the osteogenic culture of stem cells and assessment of the osteogenic potential of new therapeutic factors. PMID:21764442

Samuel, Raymond E.; Shukla, Anita; Paik, Daniel H.; Wang, Mary X.; Fang, Jean C.; Schmidt, Daniel J.

2011-01-01

200

Subwavelength surface plasmons based on novel structures and metamaterials  

NASA Astrophysics Data System (ADS)

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.

Yang, Ruoxi

201

A large surface photomultiplier based on SiPMs  

NASA Astrophysics Data System (ADS)

Light detection through photosensitive devices represents one of the key issues for a large variety of experiments. In the recent years, Silicon PhotoMultipliers (SiPMs) based on limited Geiger-mode avalanche have been extensively studied in view of their future applications. However, their use is strongly limited by their small sensitive surfaces and by the fact that any increment in the surface turns out into an increase of the dark count rate. In the present work we describe the dark count rate reduction obtained by using a FPGA-based logical circuit for fast pre-processing of pulses from a 3×3 matrix of SiPMs. The prototype we developed supports two SiPMs: we show that a rate reduction from 6.6 Mcps (Mega counts per second) down to 0.436 Mcps at the lowest threshold (0.5 photon-equivalent) and from 1.2 kcps down to 0.02 cps for the highest threshold (3.5 photon-equivalent) is obtainable.

Barbarino, Giancarlo; de Asmundis, Riccardo; De Rosa, Gianfranca; Vivolo, Daniele; Mollo, Carlos Maximiliano

2013-10-01

202

Imidazolium-based ionic liquids grafted on solid surfaces.  

PubMed

Supported ionic liquids (SILs), which refer to ionic liquids (ILs) immobilized on supports, are among the most important derivatives of ILs. The immobilization process of ILs can transfer their desired properties to substrates. Combination of the advantages of ILs with those of support materials will derive novel performances while retaining properties of both moieties. SILs have been widely applied in almost all of fields involving ILs, and have brought about drastic expansion of the ionic liquid area. As green media in organic catalytic reactions, based on utilizing the ability of ILs to stabilize the catalysts, they have many advantages over free ILs, including avoiding the leaching of ILs, reducing their amount, and improving the recoverability and reusability of both themselves and catalysts. This has critical significance from both environmental and economical points of view. As novel functional materials in surface science and material chemistry, SILs are ideal surface modifying agents. They can modify and improve the properties of solids, such as wettability, lubricating property, separation efficiency and electrochemical response. With the achievements in the field of ILs, using magnetic nanoparticles (MNPs) to SILs has drawn increasing attention in catalytic reactions and separation technologies, and achieved substantial progress. The combination of MNPs and ILs renders magnetic SILs, which exhibit the unique properties of ILs as well as facile separation by an external magnetic field. In this article, we focus on imidazolium-based ILs covalently grafted to non-porous and porous inorganic materials. The excellent stability and durability of this kind of SILs offer a great advantage compared with free ILs and IL films physically adsorbed on substrates without covalent bonds. Including examples from our own research, we overview mainly the applications and achievements of covalent-linked SILs in catalytic reactions, surface modification, separation technologies and electrochemistry. PMID:25000475

Xin, Bingwei; Hao, Jingcheng

2014-09-22

203

Lunar surface base propulsion system study, volume 1  

NASA Technical Reports Server (NTRS)

The efficiency, capability, and evolution of a lunar base will be largely dependent on the transportation system that supports it. Beyond Space Station in low Earth orbit (LEO), a Lunar-derived propellant supply could provide the most important resource for the transportation infrastructure. The key to an efficient Lunar base propulsion system is the degree of Lunar self-sufficiency (from Earth supply) and reasonable propulsion system performance. Lunar surface propellant production requirements must be accounted in the measurement of efficiency of the entire space transportation system. Of all chemical propellant/propulsion systems considered, hydrogen/oxygen (H/O) OTVs appear most desirable, while both H/O and aluminum/oxygen propulsion systems may be considered for the lander. Aluminized-hydrogen/oxygen and Silane/oxygen propulsion systems are also promising candidates. Lunar propellant availability and processing techniques, chemical propulsion/vehicle design characteristics, and the associated performance of the total transportation infrastructure are reviewed, conceptual propulsion system designs and vehicle/basing concepts, and technology requirements are assessed in context of a Lunar Base mission scenario.

1987-01-01

204

Engineering aperiodic nanostructured surfaces for scattering-based optical devices  

NASA Astrophysics Data System (ADS)

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.

Lee, Yuk Kwan Sylvanus

205

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

PubMed Central

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

Anick, D; Rota, G C

1991-01-01

206

Micro-and nanostructured silicon-based superomniphobic surfaces.  

PubMed

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

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

2014-02-15

207

Comparison of frictional forces between aesthetic orthodontic coated wires and self-ligation brackets  

PubMed Central

Objective The purpose of this study was to evaluate the clinical efficacy of polymer- and rhodium-coated wires compared to uncoated wires by measuring the frictional forces using self-ligation brackets. Methods 0.016-inch nickel titanium (NiTi) wires and 0.017 × 0.025-inch stainless steel (SS) wires were used, and the angulations between the brackets and wires were set to 0°, 5°, and 10°. Upper maxillary premolar brackets (Clippy-C®) with a 0.022-inch slot were selected for the study and a tensile test was performed with a crosshead speed of 5 mm/min. The maximum static frictional forces and kinetic frictional forces were recorded and compared. Results The maximum static frictional forces and the kinetic frictional forces of coated wires were equal to or higher than those of the uncoated wires (p < 0.05). The maximum static frictional forces of rhodium-coated wires were significantly higher than those of polymer-coated wires when the angulations between the brackets and wires were set to (i) 5° in the 0.016-inch NiTi wires and (ii) all angulations in the 0.017 × 0.025-inch SS wires (p < 0.05). The kinetic frictional forces of rhodium-coated wires were higher than those of polymer-coated wires, except when the angulations were set to 0° in the 0.016-inch NiTi wires (p < 0.05). Conclusions Although the frictional forces of the coated wires with regards to aesthetics were equal to or greater than those of the uncoated wires, a study under similar conditions regarding the oral cavity is needed in order to establish the clinical implications. PMID:25133130

Kim, Yunmi; Cha, Jung-Yul; Hwang, Chung-Ju; Tahk, Seon Gun

2014-01-01

208

Evaluation of acquired acid resistance of enamel surrounding orthodontic brackets irradiated by laser and fluoride application.  

PubMed

Demineralization of enamel around orthodontic brackets is a clinical problem which can lead to some esthetic concerns like white spot lesions. The aim of this in vitro study was to evaluate the effect of the Er, Cr:YSGG laser and fluoride application on the acid resistance of enamel adjacent to orthodontic brackets. A total of 60 healthy, permanent, human premolars were selected and bonded with brackets, then they were randomly assigned to four groups (n?=?15): topical APF gel (1.23 % F, pH 3.5, for 4 min); Er,Cr:YSGG laser (P:0.25 W, E:12.5 mJ, RR:20 Hz, PD:140 ?s, 11 % air, without water, for 10 s); fluoride + laser group (F + L), and control group (C). All specimens were demineralized for 10 days in a 0.2 M acetate buffer solution, and the calcium content were subsequently determined with atomic absorption spectrometry. There were significant differences between the calcium content of F + L and F group in comparison to control group. The least concentration of calcium was seen in F + L group, and the most value was observed in C group. Combination of Er, Cr:YSGG laser with fluoride and fluoride alone decreased enamel solubility significantly more than laser alone. In addition, combination of laser and fluoride leads to less consumption of fluoride amount. And patients can use it at the beginning of treatment instead of daily use of fluoride. So we suggest using it in preventing enamel demineralization around orthodontic brackets. PMID:23624699

Fekrazad, Reza; Ebrahimpour, Leila

2014-11-01

209

A glucose biosensor based on surface active maghemite nanoparticles.  

PubMed

A simple carbon paste (CP) electrode, modified with novel maghemite (?-Fe2O3) nanoparticles, called SAMNs (surface active maghemite nanoparticles) and characterized by a mean diameter of about 10nm, has been developed. The electrode catalyzes the electro-reduction of hydrogen peroxide at low applied potentials (-0.1 V vs SCE). In order to improve the electrocatalytic properties of the modified electrode an ionic liquid, namely 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6), was introduced. At -0.1 V, the sensitivity of the SAMN-BMIM-PF6-CP electrode was 206.51 nA ?M(-1)cm(-2), with a detection limit (S/N=3) of 0.8 ?M, in the 0-1.5mM H2O2 concentration range. Furthermore, glucose oxidase was immobilized on the surface of maghemite nanoparticles as a monomolecular layer, by a bridge constituted of rhodamine B isothiocyanate, leading to a fluorescent, magnetic drivable nanocatalyst, containing 10 ± 2 enzyme molecules per nanoparticle. The resulting enzyme electrode presents a linear calibration curve toward glucose in solution in the concentration range of 0-1.5mM glucose, characterized by a sensitivity of 45.85 nA ?M(-1)cm(-2) and a detection limit (S/N=3) of 0.9 ?M. The storage stability of the system was evaluated and a half-life of 2 months was calculated, if the electrode is stored at 4°C in buffer. The present work demonstrates the feasibility of these surface active maghemite nanoparticles as efficient hydrogen peroxide electro-catalyst, which can be easily coupled to hydrogen peroxide producing enzymes in order to develop oxidase based reagentless biosensor devices. PMID:23454337

Baratella, Davide; Magro, Massimiliano; Sinigaglia, Giulietta; Zboril, Radek; Salviulo, Gabriella; Vianello, Fabio

2013-07-15

210

Commuting symmetry operators of the Dirac equation, Killing-Yano and Schouten-Nijenhuis brackets  

NASA Astrophysics Data System (ADS)

In this paper we derive the most general first-order symmetry operator commuting with the Dirac operator in all dimensions and signatures. Such an operator splits into Clifford even and Clifford odd parts which are given in terms of odd Killing-Yano and even closed conformal Killing-Yano inhomogeneous forms, respectively. We study commutators of these symmetry operators and give necessary and sufficient conditions under which they remain of the first-order. In this specific setting we can introduce a Killing-Yano bracket, a bilinear operation acting on odd Killing-Yano and even closed conformal Killing-Yano forms, and demonstrate that it is closely related to the Schouten-Nijenhuis bracket. An important nontrivial example of vanishing Killing-Yano brackets is given by Dirac symmetry operators generated from the principal conformal Killing-Yano tensor [hep-th/0612029]. We show that among these operators one can find a complete subset of mutually commuting operators. These operators underlie separability of the Dirac equation in Kerr-NUT-(A)dS spacetimes in all dimensions [arXiv:0711.0078].

Cariglia, Marco; Krtouš, Pavel; Kubiz?ák, David

2011-07-01

211

Evaluation of Shear Bond Strength of Orthodontic Brackets Bonded with Nano-Filled Composites  

PubMed Central

Objectives: The purpose of this study was to evaluate the shear bond strength (SBS) of orthodontic brackets bonded with two types of nano-composites in comparison to a conventional orthodontic composite. Materials and Methods: Sixty extracted human first premolars were randomly divided into 3 groups each containing 20 teeth. In group I, a conventional orthodontic composite (Transbond XT) was used to bond the brackets, while two nano-composites (Filtek TM Supreme XT and AELITE Aesthetic Enamel) were used in groups II and III respectively. The teeth were stored in distilled water at 37°C for 24 hours, thermocycled in distilled water and debonded with a universal testing machine at a crosshead speed of 1 mm/min. The adhesive remnant index (ARI) was also evaluated using a stereomicroscope. Results: AELITE Aesthetic Enamel nano-composite revealed a SBS value of 8.44±2.09 MPa, which was higher than Transbond XT (6.91±2.13) and Filtek TM Supreme XT (6.04±2.01). Statistical analysis revealed a significant difference between groups II and III (P < 0.05). No significant difference was found between groups I and III, and between groups I and II (P > 0.05). Evaluation of ARI showed that Transbond XT left fewer adhesive remains on teeth after debonding. Conclusion: Results of this study indicate that the aforementioned nano-composites can be successfully used for bonding orthodontic brackets. PMID:24910655

Chalipa, Javad; Akhondi, Mohammad Sadegh Ahmad; Arab, Sepideh; Kharrazifard, Mohammad Javad; Ahmadyar, Maryam

2013-01-01

212

Hippocampal shape analysis: surface-based representation and classification  

NASA Astrophysics Data System (ADS)

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.

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

2003-05-01

213

Plasma-based physical vapor deposition surface engineering processes  

NASA Astrophysics Data System (ADS)

Plasma-based physical vapor deposition (PVD) process developments occurring over the past few decades now allow the production of tribological coatings with properties which were previously unachievable. These new coatings will be critical in the creation of new products with improved functionality and performance, which will have a dramatic impact on, for example, their operating efficiency and lifetime. The key pioneers behind these PVD developments are discussed here, together with some significant process innovations. The latter include ionization-enhancing systems, such as thermionic assistance and arc evaporation, as well as unbalanced magnetron sputtering and magnetic plasma confinement. These developments have provided the impetus behind the recent growth in the technology field which we now know as surface engineering, and the recognition that surfaces provide the functionality and durability for almost all engineered products. Vacuum plasma technologies can thus be regarded as critical, not only for functional devices and thin film applications (for which their importance was previously most recognized), but also for structural product applications; they will thus underpin the entire spectrum of manufacturing industry.

Matthews, Allan

2003-09-01

214

Guiding Rydberg atoms above surface-based transmission lines  

NASA Astrophysics Data System (ADS)

Beams of helium atoms in selected Rydberg-Stark states with principal quantum number n=52 and electric dipole moments as large as 9910 D have been guided and deflected in the electrostatic fields surrounding surface-based electrical transmission lines. The guided atoms were detected by pulsed-electric-field ionization. Information on their position at the time of ionization was obtained from the flight time of the resulting ions to a microchannel plate detector. Comparison of the experimentally recorded data with the results of numerical calculations of particle trajectories through the guide highlight the sensitivity of the guided signal to the interaction of the atoms with each other and the surrounding 300 K blackbody radiation field.

Lancuba, P.; Hogan, S. D.

2013-10-01

215

Frequency Selective Surface Based Bandpass Filter for THz Communication System  

NASA Astrophysics Data System (ADS)

In this work, a band pass filter based on frequency selective surface (FSS) is presented. The resonance of the FSS is achieved by perforating slot type ring structure on an Aluminum layer. To ensure adequate mechanical strength, this structure is again supported by a dielectric layer. The physical dimensions of the FSS, i.e. ring radius, slot width, cell dimension and width of the layers all are responsible for the resonance behavior. In its electrical equivalent circuit, these dimensions act as inductor and capacitor. The center frequency of the designed filter is at 0.16 THz with a -3 dB bandwidth of 18 GHz. This filter can be utilized as a part of any THz communication system to achieve application specific frequency discrimination. The simulation has been carried by using commercial software-CST Microwave Studio. The performance of the fabricated FSS is evaluated by Microwave Vector Network Analyzer.

Das, Subrata; Reza, Khan Mamun; Habib, Md. Ahsan

2012-11-01

216

Chemical and Biological Sensing Based on the Surface Photovoltage Measurement of the Si Surface Potential Barrier  

NASA Astrophysics Data System (ADS)

Chemical and biological species deposited on the crystalline silicon surface created surface barrier changes that were detected using the non-contact Surface Photovoltage technique. The magnitude of the surface barrier modifications provided a signature allowing quantification of the sensed species. The simplicity and sensitivity of this technique offers an exciting opportunity for a new type of low cost sensing devices.

Nauka, K.; Li, Zhiyong; Kamins, T. I.

2005-06-01

217

Implementation of Frictional Contact Conditions in Surface to Surface, Mortar Based Computational Frameworks  

SciTech Connect

A number of recent works have established the mortar technique as an accurate and robust spatial discretization method for contact problems in computational solid mechanics. Since methods based on this idea rely on an integral, non-local representation of the contact operators, their formulation is somewhat more involved than is true for more traditional ''point to surface'' contact algorithms; in particular, the integral projections have nontrivial linearizations in the fully large deformation context. In this work, we concentrate on another aspect of formulations of this type--definition and implementation of frictional contact operators within the mortar contact framework. Issues associated with frame indifference of frictional tractions and kinematics are discussed, and a numerical demonstration of the technique is given.

Laursen, T A; Yang, B; Puso, M A

2004-04-01

218

Highly antibacterial activity of N-doped TiO2 thin films coated on stainless steel brackets under visible light irradiation  

NASA Astrophysics Data System (ADS)

In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO2 thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi; Liu, Bin; Cao, Baocheng

2014-08-01

219

Wave-and Anemometer-Based Sea Surface Wind (WASWind) for Climate Change Analysis*  

E-print Network

Wave- and Anemometer-Based Sea Surface Wind (WASWind) for Climate Change Analysis* HIROKI TOKINAGA-based measurements of sea surface wind speed display a spurious upward trend due to increases in anemometer height (ICOADS). The Wave- and Anemometer-based Sea surface Wind (WASWind) dataset is available for wind velocity

Xie, Shang-Ping

220

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases for  

E-print Network

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases explores the possibilities provided by satellite-based surface solar irradiation databases synthesis of 17 satellite-based surface solar irradiation databases available so far is presented through

Paris-Sud XI, Université de

221

Surface plasmon resonance sensor based on spectral interferometry: numerical analysis.  

PubMed

In this paper, we introduce a numerical simulation of a phase detecting surface plasmon resonance (SPR) scheme based on spectral interference. Based on the simulation, we propose a method to optimize various aspects of SPR sensors, which enables better performance in both measurement range (MR) and sensitivity. In the simulation, four parameters including the spectrum of the broadband light source, incident angle, Au film thickness, and refractive index of the prism coupler are analyzed. The results show that it is a good solution for better performance to use a warm white broadband (625-800 nm) light source, a divergence angle of the collimated incident light less than 0.02°, and an optimized 48 nm thick Au film when a visible broadband light source is used. If a near-IR light source is used, however, the Au film thickness should be somewhat thinner according the specific spectrum. In addition, a wider MR could be obtained if a prism coupler with higher refractive index is used. With all the parameters appropriately set, the SPR MR could be extended to 0.55 refractive index units while keeping the sensitivity at a level of 10(-8). PMID:23669838

Zhang, Yunfang; Li, Hui; Duan, Jingyuan; Shi, Ancun; Liu, Yuliang

2013-05-10

222

Evaluation of upper limb muscle fatigue based on surface electromyography.  

PubMed

Fatigue is believed to be a major contributory factor to occupational injuries in machine operators. The development of accurate and usable techniques to measure operator fatigue is therefore important. In this study, we used a novel method based on surface electromyography (sEMG) of the biceps brachii and the Borg scale to evaluate local muscle fatigue in the upper limb after isometric muscle action. Thirteen young males performed isometric actions with the upper limb at different force levels. sEMG activities of the biceps brachii were recorded during the actions. Borg scales were used to evaluate the subjective sensation of local fatigue of the biceps brachii after the actions. sEMG activities were analyzed using the one-third band octave method, and an equation to determine the degree of fatigue was derived based on the relationship between the variable and the Borg scale. The results showed that the relationship could be expressed by a conic curve, and could be used to evaluate muscle fatigue during machine operation. PMID:22038006

Zhou, Qianxiang; Chen, Yuhong; Ma, Chao; Zheng, Xiaohui

2011-10-01

223

The Cbf5-Nop10 Complex is a Molecular Bracket that Organizes Box H/ACA RNPs  

SciTech Connect

Box H/ACA ribonucleoprotein particles (RNPs) catalyze RNA pseudouridylation and direct processing of ribosomal RNA, and are essential architectural components of vertebrate telomerases. H/ACA RNPs comprise four proteins and a multihelical RNA. Two proteins, Cbf5 and Nop10, suffice for basal enzymatic activity in an archaeal in vitro system. We now report their cocrystal structure at 1.95-A resolution. We find that archaeal Cbf5 can assemble with yeast Nop10 and with human telomerase RNA, consistent with the high sequence identity of the RNP componenets between archaea and eukarya. Thus, the Cbf5-Nop10 architecture is phylogenetically conserved. The structure shows how Nop10 buttresses the active site of Cbf5, and it reveals two basic troughs that bidirectionally extend the active site cleft. Mutagenesis results implicate an adjacent basic patch in RNA binding. This tripartite RNA-binding surface may function as a molecular bracket that organizes the multihelical H/ACA and telomerase RNAs.

Hamma, Tomoko; Reichow, Steve L.; Varani, Gabriele; Ferre-D'Amare, Adrian R.

2005-12-01

224

A new Voronoi-based surface reconstruction algorithm  

Microsoft Academic Search

We describe our experience with a new algorithm for the reconstructionof surfaces from unorganized sample points in IR3. The algorithmis the first for this problem with provable guarantees. Givena "good sample" from a smooth surface, the output is guaranteed tobe topologically correct and convergent to the original surface asthe sampling density increases. The definition of a good sample isitself interesting:

Nina Amenta; Marshall W. Bern; Manolis Kamvysselis

1998-01-01

225

Tribological Properties of Laser Surface Texturing and Molybdenizing Duplex-Treated Ni-Base Alloy  

Microsoft Academic Search

Laser surface texturing (LST) and surface molybdenizing duplex-treatment was performed on Ni-base alloy in order to improve its wear resistance at high temperature. Surface molybdenizing was performed on the laser surface textured Ni-base alloy by a double glow plasma surface alloying technology. The friction and wear properties of the duplex-treated, the single-treated, and the untreated alloys were tested on a

JIANLIANG LI; DANGSHENG XIONG; HONGYAN WU; ZHONGJIA HUANG; JIHUI DAI; RAJNESH TYAGI

2010-01-01

226

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

227

Controlling silicon nanowire growth direction via surface chemistry.  

PubMed

We report on the first in situ chemical investigation of vapor-liquid-solid semiconductor nanowire growth and reveal the important, and previously unrecognized, role of transient surface chemistry near the triple-phase line. Real-time infrared spectroscopy measurements coupled with postgrowth electron microscopy demonstrate that covalently bonded hydrogen atoms are responsible for the (left angle bracket 111 right angle bracket) to (left angle bracket 112 right angle bracket) growth orientation transition commonly observed during Si nanowire growth. Our findings provide insight into the root cause of this well-known nanowire growth phenomenon and open a new route to rationally engineer the crystal structure of these nanoscale semi-conductors. PMID:22594623

Shin, Naechul; Filler, Michael A

2012-06-13

228

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

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

229

The effect of perturbations on resistance to sliding in second-order moments comparing two different bracket types  

PubMed Central

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.

Wong, Justin K; Romanyk, Dan L; Toogood, Roger W; Heo, Giseon; Carey, Jason P

2014-01-01

230

Gis-Based Surface Analysis of Archaeological Finds  

NASA Astrophysics Data System (ADS)

The international research project HiMAT (History of Mining Activities in the Tyrol and adjacent areas) is dedicated to the study of mining history in the Eastern Alps by various scientific disciplines. The aim of this program is the analysis of the mining activities' impacts on environment and human societies. Unfortunately, there is only a limited number of specific regions (e.g. Mitterberg) to offer possibilities to investigate the former mining expansions. Within this multidisciplinary project, the archaeological sites and finds are analyzed by the Surveying and Geoinformation Unit at the University of Innsbruck. This paper shows data fusion of different surveying and post-processing methods to achieve a photo-realistic digital 3D model of one of these most important finds, the Bronze Age sluice box from the Mitterberg. The applied workflow consists of four steps: 1. Point cloud processing, 2. Meshing of the point clouds and editing of the models, 3. Image orientation, bundle and image adjustment, 4. Model texturing. In addition, a short range laser scanning survey was organized before the conservation process of this wooden find. More accurate research opportunities were offered after this detailed documentation of the sluice box, for example the reconstruction of the broken parts and the surface analysis of this archaeological object were implemented using these high-resolution datasets. In conclusion, various unperceived patterns of the wooden boards were visualized by the GIS-based tool marks investigation.

Kovács, K.; Hanke, K.; Moser, M.

2011-09-01

231

Ground Based Interferometric Radar for Surface Monitoring Applications  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

232

Evaluation of surface roughness based on monochromatic speckle correlation using image processing  

Microsoft Academic Search

The measurement of roughness on machined surfaces is of great importance for manufacturing industries as the roughness of a surface has a considerable influence on its quality and function of products. In this paper, an experimental approach for surface roughness measurement based on the coherent speckle scattering pattern caused by a laser beam on the machined surfaces (grinding and milling)

B. Dhanasekar; N. Krishna Mohan; Basanta Bhaduri; B. Ramamoorthy

2008-01-01

233

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

234

Deep subwavelength waveguiding and focusing based on designer surface plasmons.  

PubMed

We experimentally demonstrate focusing and guiding electromagnetic (EM) waves in a designer surface plasmonic waveguide with deep subwavelength mode cross section. Our experiments show that a metal grating with suitable parameters, functioning as a designer surface plasmonic waveguide, can support deep subwavelength surface modes and the width of the modes can be squeezed also into deep subwavelength by tapering the width of the waveguide. The results provide a new insight into deep subwavelength waveguiding and focusing. PMID:20941046

Zhao, Wangshi; Eldaiki, Omar M; Yang, Ruoxi; Lu, Zhaolin

2010-09-27

235

Surface modification of polymer-based microfluidic devices  

Microsoft Academic Search

We report the chemical modification of poly(methyl methacrylate) (PMMA), and poly(carbonate) (PC) surfaces for applications in microfluidic systems. For PMMA, a reaction of the surface methyl ester groups with a monoanion of ?,?-diaminoalkanes (aminolysis reaction) to yield amine-terminated PMMA surfaces will be described. Furthermore, it was found that the amine functionalities were tethered to the PMMA backbone through an alkane

Steven A Soper; Alyssa C Henry; Bikas Vaidya; Michelle Galloway; Musundi Wabuyele; Robin L McCarley

2002-01-01

236

Corrosion protection of aluminum by silane-based surface treatment  

NASA Astrophysics Data System (ADS)

The possibility of using silane coupling agents as replacements for chromate treatments was investigated for aluminum substrates. In order to understand the influence of deposition parameters on silane film formation, pure Al substrates were used to study the interaction between silane coupling agents and aluminum surfaces. The silane films formed on pure A1 substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and Time-of Flight Secondary Ion Mass Spectrometry. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation in aqueous solution. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is independent of the solution dipping time. The molecular orientation of the applied silane film is determined by the pH value of the applied silane solution and the isoelectic point of the metal substrates. The deposition window in terms of pH value for A1 substrates is between 4 and 7. The total surface energy of silane-coated A1 substrate decreases with film aging time, the decreased rate, however, is determined by the nature of silane coupling agents. Based on the results obtained above, a pretreatment, which involved two-step bis-(triethoxysilyl) ethane and gamma-aminopropyltriethoxysilane, was developed for Al substrates with commercial polyester and polyurethane paints. The results of salt spray testing, cyclic corrosion testing, and electrochemical impedance spectroscopy showed that this treatment provided the same level of corrosion performance as the treatment of phosphating plus a final chromate rinse. The likely reasons for excellent performance are discussed in terms of the physical and chemical characteristics of the treatment layers and their stability in the under-film corrosion environment. Salt spray test results showed that two-step BTSE/gamma-APS could provide the same or better corrosion protection than that offered by a standard chromate treatment. Polyester or polyurethane powder-painted Al panels, pretreated with this treatment, also displayed excellent corrosion performances in the salt spray test and filiform corrosion test. Thus, the advantage of this treatment is that is combines a temporary rust prevention and a permanent prepaint treatment into one simple approach. Electrochemical impedance spectroscopy was used to study the various pre-paint treatments under the polyester paint. It provides more detailed mechanistic information about corrosion processes than salt spray test and filiform corrosion test. However, combination of corrosion tests that involve different corrosion mechanisms may still be necessary to have a better understanding of corrosion behavior of a new treatment.

Song, Jun

237

Automatic vertebral identification using surface-based registration  

NASA Astrophysics Data System (ADS)

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.

Herring, Jeannette L.; Dawant, Benoit M.

2000-06-01

238

A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences within the  

E-print Network

A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences preterm and 19 term-born neonates at term-equivalent age. We reconstructed striatal surfaces from manually R, An X, Lao Y, et al. (2013) A Multivariate Surface-Based Analysis of the Putamen in Premature

Wang, Yalin

239

Feature-based handling of surface faults in compact disc players  

Microsoft Academic Search

In this paper a novel method called feature-based control is presented. The method is designed to improve compact disc players’ handling of surface faults on the discs. The method is based on a fault-tolerant control scheme, which uses extracted features of the surface faults to remove those from the detector signals used for control during the occurrence of surface faults.

Peter Fogh Odgaard; Jakob Stoustrup; Palle Andersen; Mladen Victor Wickerhauser; Henrik Fløe Mikkelsen

2006-01-01

240

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases for  

E-print Network

2013 ISES Solar World Congress Review of satellite-based surface solar irradiation databases explores the possibilities provided by satellite-based surface solar irradiation databases. Selection and/or peer-review under responsibility of ISES Keywords: surface solar irradiation; satellite

Recanati, Catherine

241

Surface-based bedload transport relation for gravel rivers  

Microsoft Academic Search

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

G. Parker

1990-01-01

242

Trochlear surface reconstruction and evaluation based on laser scanner acquisition  

Microsoft Academic Search

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.

R. Synave; C. Couture-Veschambre

2010-01-01

243

VBGVBG3/7/2006MODIFIED LEAK DETECTOR BRACKET1 2. WELDING & INSPECTIONS SHALL BE PERFORMED  

E-print Network

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

McDonald, Kirk

244

Probability Bracket Notation, Term Vector Space, Concept Fock Space and Induced Probabilistic IR Models  

E-print Network

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.

Xing M. Wang

2011-03-20

245

LTS Gradiometers Based-On Superconducting Imaging Surface Design  

SciTech Connect

Gradiometer-like devices can be built using a superconducting imaging surface design. Such devices behave similarly to conventional wire-wound gradiometers for nearby magnetic sources. A large gradiometer array can be built by placing SQUID magnetometers close to the surface of a large superconducting plane. The most attractive advantage of such a gradiometer array is the ability to change a baseline for all channels simultaneously by mechanically moving the superconducting imaging surface relative to the sensor array. This can easily be accomplished even when the gradiometer array is cold. We built, experimentally tested, and simulated both first- and second-order gradiometer-like devices with adjustable baseline using the superconducting imaging surface design. First-order radial gradiometer sensors were made by placing planar magnetometers parallel to and near the superconducting imaging surface. A second-order electronic gradiometer was realized by subtracting the output from two of the first-order gradiometers described above.

Matlachov, A.N.; Kraus, R.H., Jr.; Espy, M.A.

1999-06-21

246

Rapid debonding of polycrystalline ceramic orthodontic brackets with an Er:YAG laser: an in vitro study.  

PubMed

The usefulness of erbium-doped yttrium aluminum garnet laser irradiation for debonding ceramic brackets is assessed using a single laser pulse. Damon Clear brackets were chosen for their 85% transmission of 2.94 ?m radiation and were bonded to 20 human third molars using the Blugloo adhesive system. Laser parameters comprised of 600 mJ pulse energy with 800 ?s duration, 1.3 mm fiber tip. Light microscopy was used to assess Adhesive Remnant Index (ARI) scores, and scanning electron microscope (SEM) images were taken of the cross-section of the enamel-adhesive interface. Nineteen brackets (95%) were successfully debonded with a single laser pulse, while one bracket (5%) required eight pulses for debonding. For all teeth, the SEM analysis showed no signs of damage to the enamel, and ARI scores of three were observed, supporting the result that the laser effect is confined in the adhesive. The presented laser parameters are able to rapidly debond suitable brackets. The debonding mechanism was concluded to be thermomechanical ablation for single pulse debonding. PMID:23525867

Mundethu, Ambili Roselina; Gutknecht, Norbert; Franzen, Rene

2014-09-01

247

Orthodontic bracket shear bond strengths produced by two high-power light-emitting diode modes and halogen light.  

PubMed

The aim of this in vitro study was to compare the shear bond strength of orthodontic brackets cured with two different high-power light-emitting diode (LED) polymerization modes with traditional halogen polymerization. A total of forty-five extracted human premolar teeth were randomly divided into three groups. Each group consisted of 15 teeth mounted in an acrylic block. Following a standard enamel etching protocol, orthodontic brackets were cured on the first group of teeth with fast-mode LED, the second group with soft-start mode LED, and on the last group with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a universal testing machine. The results showed that brackets cured with soft-start mode LED produced the highest shear bond strengths (23.86 +/- 6.20 MPa). No significant difference was found between fast-mode LED (17.14 +/- 5.75 MPa) and the halogen group (17.38 +/- 5.41 MPa) (P > .05). The LED is effective for bonding metal brackets to teeth, and the soft-start mode gives higher bond strengths than the fast mode. PMID:16283816

Türkkahraman, Hakan; Küçüke?men, H Cenker

2005-09-01

248

Probabilistic Surfaces: Point Based Primitives to Show Surface Uncertainty Gevorg Grigoryan  

E-print Network

Efficient and informative visualization of surfaces with uncertain- ties is an important topic with many on the problem of visualizing surfaces with uncertainties. This is a very important subproblem because. Or perhaps when visualizing looking at a visualization of ones brain obtained from Magnetic Resonance data

Rheingans, Penny

249

Moire based optical surface profiler for the minting industry  

NASA Astrophysics Data System (ADS)

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.

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

1992-12-01

250

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

PubMed

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

Li, Zhongyang; Butun, Serkan; Aydin, Koray

2014-08-26

251

Cauchy problem as a two-surface based `geometrodynamics'  

E-print Network

Four-dimensional spacetimes foliated by a two-parameter family of homologous two-surfaces are considered in Einstein's theory of gravity. By combining a 1+(1+2) decomposition, the canonical form of the spacetime metric and a suitable specification of the conformal structure of the foliating two-surfaces a gauge fixing is introduced. It is shown that, in terms of the chosen geometrically distinguished variables, the 1+3 Hamiltonian and momentum constraints can be recast into the form of a parabolic equation and a first order symmetric hyperbolic system, respectively. Initial data to this system can be given on one of the two-surfaces foliating the three-dimensional initial data surface. The 1+3 reduced Einstein's equations are also determined. By combining the 1+3 momentum constraint with the reduced system of the secondary 1+2 decomposition a mixed hyperbolic-hyperbolic system is formed. It is shown that solutions to this mixed hyperbolic-hyperbolic system are also solutions to the full set of Einstein's equations provided that the 1+3 Hamiltonian constraint is solved on the initial data surface $\\Sigma_0$ and the 1+2 Hamiltonian and momentum type expressions vanish on a world-tube yielded by the Lie transport of one of the two-surfaces foliating $\\Sigma_0$ along the time evolution vector field. Whenever the foliating two-surfaces are compact without boundary in the spacetime and a regular origin exists on the time-slices---this is the location where the foliating two-surfaces smoothly reduce to a point---it suffices to guarantee that the 1+3 Hamiltonian constraint holds on the initial data surface. A short discussion on the use of the geometrically distinguished variables in identifying the degrees of freedom of gravity are also included.

István Rácz

2014-09-17

252

Structural Surface of Mould Softness Abrasive Flow Precision Polishing Machining Method Based on VOF  

Microsoft Academic Search

Aiming to improve the surface roughness of precision mould structural surface in finish machining, a new mould structural surface no-tool precision polishing method based on softness abrasive flow was brought forward. Dynamical model of softness abrasive flow in bound flow oriented to mould structural surface precision machining was established based on liquid-solid two-phase flow coupling theory and a continuous media

Bo Tang; Shiming Ji; Dapeng Tan

2010-01-01

253

Surface Tension Evaluation method based on geometrical interface reconstruction  

NASA Astrophysics Data System (ADS)

This paper proposes an evaluation method of surface tension without using curvature of interface. Curvature of interface is needed to evaluate surface tension in the existing methods such as CSF model. However, stable evaluation of curvature requires finite region of interface between fluids which prevents efficient simulation of violated multi phase flow with large numbers of bubbles and droplets. The objective of the proposed methods is efficient surface tension modeling which enables simulation of highly violated air-water flow with minor number of computational cells. The proposed model directly evaluates surface tension from cross line between cell boundary and interface and does not require finite width of interface region. Two and three dimensional test cases are carried out to confirm that the method provides qualitatively appropriate results.

Fujioka, Susumu; Ushijima, Satoru

254

Surface skeleton generation based on 360-degree profile scan  

E-print Network

A rapid prototyping method is invented, which works on a specific data structure produced by an optical metrology technique: 360-degree surface profile scanning. A computer algorithm takes an object profile data, restructure ...

Chen, Lujie

255

Surfaces  

E-print Network

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; ...

DeMaio, Ernest Vincent, 1964-

1989-01-01

256

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

SciTech Connect

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.

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

257

Production of A357 motor mount bracket by the metal compression forming process  

SciTech Connect

The use of aluminum alloy castings for safety critical structural components such as engine mount brackets, steering knuckles, and control arms, offers significant opportunities for achieving weight reduction in automobiles, since they are typically about half the weight of the steel, cast iron, or ductile iron component that they replace. Metal Compression Forming (MCF) is a variant of the squeeze casting process, in which molten metal is allowed to solidify under pressure in order to close porosity and form a sound part. However, the MCF process applies pressure on the entire mold face, thereby directing pressure on all regions of the casting and producing a uniformly sound part. The process is capable of producing parts with properties close to those of forgings, while retaining the near net shape, complexity in geometry, and relatively low cost of the casting process. The paper describes the casting process development involved in the production of an aluminum A357 alloy motor mount bracket, including the use of a filling and solidification model to design the gating and determine process parameters. Tensile properties of the component are presented and correlated with those of forged components. Limited fatigue properties obtained by fully reversed strain controlled testing are also presented.

Viswanathan, S.; Brinkman, C.R.; Porter, W.D. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Purgert, R.M. [Precision Metal Forming Co., Garfield Heights, OH (United States)

1997-09-01

258

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

SciTech Connect

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.

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

1993-11-05

259

MR-Less Surface-Based Amyloid Assessment Based on 11C PiB PET  

PubMed Central

Background ?-amyloid (A?) plaques in brain's grey matter (GM) are one of the pathological hallmarks of Alzheimer's disease (AD), and can be imaged in vivo using Positron Emission Tomography (PET) with 11C or 18F radiotracers. Estimating A? burden in cortical GM has been shown to improve diagnosis and monitoring of AD. However, lacking structural information in PET images requires such assessments to be performed with anatomical MRI scans, which may not be available at different clinical settings or being contraindicated for particular reasons. This study aimed to develop an MR-less A? imaging quantification method that requires only PET images for reliable A? burden estimations. Materials and Methods The proposed method has been developed using a multi-atlas based approach on 11C-PiB scans from 143 subjects (75 PiB+ and 68 PiB- subjects) in AIBL study. A subset of 20 subjects (PET and MRI) were used as atlases: 1) MRI images were co-registered with tissue segmentation; 2) 3D surface at the GM-WM interfacing was extracted and registered to a canonical space; 3) Mean PiB retention within GM was estimated and mapped to the surface. For other participants, each atlas PET image (and surface) was registered to the subject's PET image for PiB estimation within GM. The results are combined by subject-specific atlas selection and Bayesian fusion to generate estimated surface values. Results All PiB+ subjects (N?=?75) were highly correlated between the MR-dependent and the PET-only methods with Intraclass Correlation (ICC) of 0.94, and an average relative difference error of 13% (or 0.23 SUVR) per surface vertex. All PiB- subjects (N?=?68) revealed visually akin patterns with a relative difference error of 16% (or 0.19 SUVR) per surface vertex. Conclusion The demonstrated accuracy suggests that the proposed method could be an effective clinical inspection tool for A? imaging scans when MRI images are unavailable. PMID:24427295

Zhou, Luping; Salvado, Olivier; Dore, Vincent; Bourgeat, Pierrick; Raniga, Parnesh; Macaulay, S. Lance; Ames, David; Masters, Colin L.; Ellis, Kathryn A.; Villemagne, Victor L.; Rowe, Christopher C.; Fripp, Jurgen

2014-01-01

260

The Discoloring Effects of Food on the Color Stability of Esthetic Brackets – an In-vitro Study  

Microsoft Academic Search

Aim:  The purpose of this study was to investigate the discoloring effect of certain foods on the color stability of esthetic brackets\\u000a made of different materials.\\u000a \\u000a \\u000a \\u000a Material and Methods:  Ten specimens of six different tooth-colored brackets were immersed for 10 days at 37 °C in various solutions (de-ionized\\u000a water, tea, coffee, red wine, orange juice, curry and cress) or exposed to accelerated

Susanne Wriedt; Ulf Schepke; Heiner Wehrbein

2007-01-01

261

Investigation of possibility of surface rupture derived from PFDHA and calculation of surface displacement based on dislocation  

NASA Astrophysics Data System (ADS)

A probability of surface rupture is important to configure the seismic source, such as area sources or fault models, for a seismic hazard evaluation. In Japan, Takemura (1998) estimated the probability based on the historical earthquake data. Kagawa et al. (2004) evaluated the probability based on a numerical simulation of surface displacements. The estimated probability indicates a sigmoid curve and increases between Mj (the local magnitude defined and calculated by Japan Meteorological Agency) =6.5 and Mj=7.0. The probability of surface rupture is also used in a probabilistic fault displacement analysis (PFDHA). The probability is determined from the collected earthquake catalog, which were classified into two categories: with surface rupture or without surface rupture. The logistic regression is performed for the classified earthquake data. Youngs et al. (2003), Ross and Moss (2011) and Petersen et al. (2011) indicate the logistic curves of the probability of surface rupture by normal, reverse and strike-slip faults, respectively. Takao et al. (2013) shows the logistic curve derived from only Japanese earthquake data. The Japanese probability curve shows the sharply increasing in narrow magnitude range by comparison with other curves. In this study, we estimated the probability of surface rupture applying the logistic analysis to the surface displacement derived from a surface displacement calculation. A source fault was defined in according to the procedure of Kagawa et al. (2004), which determined a seismic moment from a magnitude and estimated the area size of the asperity and the amount of slip. Strike slip and reverse faults were considered as source faults. We applied Wang et al. (2003) for calculations. The surface displacements with defined source faults were calculated by varying the depth of the fault. A threshold value as 5cm of surface displacement was used to evaluate whether a surface rupture reach or do not reach to the surface. We carried out the logistic regression analysis to the calculated displacements, which were classified by the above threshold. The estimated probability curve indicated the similar trend to the result of Takao et al. (2013). The probability of revere faults is larger than that of strike slip faults. On the other hand, PFDHA results show different trends. The probability of reverse faults at higher magnitude is lower than that of strike slip and normal faults. Ross and Moss (2011) suggested that the sediment and/or rock over the fault compress and not reach the displacement to the surface enough. The numerical theory applied in this study cannot deal with a complex initial situation such as topography.

Inoue, N.; Kitada, N.; Irikura, K.

2013-12-01

262

Surface plasmon polariton propagation in organic nanofiber based plasmonic waveguides.  

PubMed

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

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

263

Cauchy problem as a two-surface based `geometrodynamics'  

E-print Network

Four-dimensional spacetimes foliated by a two-parameter family of homologous two-surfaces are considered in Einstein's theory of gravity. By combining a 1+(1+2) decomposition, the canonical form of the spacetime metric and a suitable specification of the conformal structure of the foliating two-surfaces a gauge fixing is introduced. It is shown that, in terms of the chosen geometrically distinguished variables, the 1+3 Hamiltonian and momentum constraints can be recast into the form of a parabolic equation and a first order symmetric hyperbolic system, respectively. Initial data to this system can be given on one of the two-surfaces foliating the three-dimensional initial data surface. The 1+3 reduced Einstein's equations are also determined. By combining the 1+3 momentum constraint with the reduced system of the secondary 1+2 decomposition a mixed hyperbolic-hyperbolic system is formed. It is shown that solutions to this mixed hyperbolic-hyperbolic system are also solutions to the full set of Einstein's equa...

Rácz, István

2014-01-01

264

Correlation based novel detection scheme for HF Surface Wave Radar  

Microsoft Academic Search

The challenge in HF Surface Wave Radar (SWR) lies in the detection of a target signal in the background of a strong sea clutter. A novel detection scheme is proposed which assumes that for a given Range Doppler (RD) cell in absence of a target, the normalized second order sea clutter power along the azimuth cells will be correlated over

A. Gupta; Th. Fickenscher

2011-01-01

265

Contour-Based Surface Reconstruction using MPU Implicit Models  

E-print Network

the accuracy of the shape analysis and automated segmentation techniques used within a common family of atlas Multi-level Partition of Unity (MPU) implicit models to create a surface that approximately fits, implicit models, Multi-level Partition of Unity, normal estimation 1 Introduction With the enhancement

Breen, David E.

266

Standing surface acoustic wave (SSAW) based multichannel cell sorting  

PubMed Central

We introduce a novel microfluidic device for cell sorting in continuous flow using tunable standing surface acoustic waves. This method allows individual cells to be precisely directed into five different outlet channels in a single step. It is versatile, simple, label-free, non-invasive, and highly controllable. PMID:22992833

Ding, Xiaoyun; Lin, Sz-Chin Steven; Lapsley, Michael Ian; Li, Sixing; Guo, Xiang; Chan, Chung Yu Keith; Chiang, I-Kao; Wang, Lin; McCoy, J. Philip

2014-01-01

267

An ocean SAR simulator based on the distributed surface model  

Microsoft Academic Search

A synthetic aperture radar (SAR) simulator for ocean scene is an appropriate tool for better understanding such an intriguing and interesting environment. This paper presents some meaningful results of a simulation code that has been developed according to the distributed surface model. The code includes a generalized Bragg scattering return from short waves under oblique incidence

Giorgio Franceschetti; M. Migliaccio; D. Riccio

1995-01-01

268

Deforming surface simplification based on dynamic geometry sampling Frederic Payan  

E-print Network

illustrates this problem. It shows one hoof of the morphing sequence HORSE-TO-MAN at the first frame (Figure 2). During the morphing, this hoof is progressively transformed in one hand. The amount of unnecessary the fingers appear- ing during the morphing. In case of static surface meshes, this problem could be easily

Boyer, Edmond

269

Radar Absorbers Based on Frequency Selective Surfaces on Perforated Substrates  

Microsoft Academic Search

A new type of metamaterials is introduced which can be fabricated by printing metal patches on inhomogeneous, periodic substrates. Such structures without periodic substrate are known as Frequency Selective Surfaces (FSS) but they are more promising for EMC shielding than common FSS structures because both the effective dielectric permittivity and loss of the substrate can be controlled. A numerical method

Arya Fallahi; Matthew Mishrikey; Christian Hafner; Rüdiger Vahldieck

270

Highly directional liquid surface wave source based on resonant cavity  

Microsoft Academic Search

By placing a point source inside a resonant cavity structure, we present a method to realize a highly directional liquid surface wave source. The resonant cavity is surrounded by two slabs of different thickness, with each slab consisting of a finite square array of rigid cylinders standing vertically in the liquid. It is shown that more than 68% of the

Jun Mei; Chunyin Qiu; Jing Shi; Zhengyou Liu

2009-01-01

271

Image-Based Multiresolution Modeling by Surface Deformation  

Microsoft Academic Search

This paper presents a novel approach for constructing multiresolution surface modelsfrom a set of calibrated images. The output is a texture-mapped triangular surfacemesh that best matches all the input images. The mesh is obtained by deforming ageneric initial mesh such as a sphere or cube according to image and geometry-basedforces. This technique has the following key features: (1) the initial

Li Zhang; Steven M. Seitz

2000-01-01

272

Estimation of the surface reflectivity of SAR images based on a marked Poisson point process model  

Microsoft Academic Search

This paper presents stochastic models and estimation algorithms for speckled images. We treat speckle from a novel point of view: that of a carrier of useful surface information as opposed that of a contaminating noise. The stochastic models for surface scattering are based on a doubly stochastic marked Poisson point process. For each of these surface scattering statistical models, we

Jihad S. Daba; Mark R. Bell

1995-01-01

273

3D shape measurement of optical free-form surface based on fringe projection  

Microsoft Academic Search

Present a novel method of 3D shape measurement of optical free-from surface based on fringe projection. A virtual reference surface is proposed which can be used to improve the detection efficiency and realize the automation of measuring process. Sinusoidal fringe patterns are projected to the high reflected surface of the measured object. The deflection fringe patterns that modulated by the

Shaohui Li; Shugui Liu; Hongwei Zhang

2011-01-01

274

Surface transport properties of Fe-based superconductors: The influence of degradation and inhomogeneity  

NASA Astrophysics Data System (ADS)

Surface properties of Co-doped BaFe2As2 epitaxial superconducting thin films were inspected by X-ray photoelectron spectroscopy, scanning spreading resistance microscopy (SSRM), and point contact spectroscopy (PCS). It has been shown that surface of Fe-based superconductors degrades rapidly if being exposed to air, what results in suppression of gap-like structure on PCS spectra. Moreover, SSRM measurements revealed inhomogeneous surface conductivity, what is consistent with strong dependence of PCS spectra on contact position. Presented results suggest that fresh surface and small probing area should be assured for surface sensitive measurements like PCS to obtain intrinsic properties of Fe-based superconductors.

Plecenik, T.; Gregor, M.; Sobota, R.; Truchly, M.; Satrapinskyy, L.; Kurth, F.; Holzapfel, B.; Iida, K.; Kus, P.; Plecenik, A.

2013-07-01

275

Nanosensors based on functionalized nanoparticles and surface enhanced raman scattering  

DOEpatents

Surface-Enhanced Raman Spectroscopy (SERS) is a vibrational spectroscopic technique that utilizes metal surfaces to provide enhanced signals of several orders of magnitude. When molecules of interest are attached to designed metal nanoparticles, a SERS signal is attainable with single molecule detection limits. This provides an ultrasensitive means of detecting the presence of molecules. By using selective chemistries, metal nanoparticles can be functionalized to provide a unique signal upon analyte binding. Moreover, by using measurement techniques, such as, ratiometric received SERS spectra, such metal nanoparticles can be used to monitor dynamic processes in addition to static binding events. Accordingly, such nanoparticles can be used as nanosensors for a wide range of chemicals in fluid, gaseous and solid form, environmental sensors for pH, ion concentration, temperature, etc., and biological sensors for proteins, DNA, RNA, etc.

Talley, Chad E. (Brentwood, CA); Huser, Thomas R. (Livermore, CA); Hollars, Christopher W. (Brentwood, CA); Lane, Stephen M. (Oakland, CA); Satcher, Jr., Joe H. (Patterson, CA); Hart, Bradley R. (Brentwood, CA); Laurence, Ted A. (Livermore, CA)

2007-11-27

276

Aptamer-based surface plasmon fibre sensor for thrombin detection  

NASA Astrophysics Data System (ADS)

A series of surface plasmonic fibre devices were fabricated using multiple coatings deposited on a lapped section of a single mode fibre and post-fabrication UV laser irradiation processing with a phase mask, producing a surface relief grating structure. These devices showed high spectral sensitivity in the aqueous index regime ranging up to 4000 nm/RIU for wavelength and 800 dB/RIU for intensity. The devices were then coated with human thrombin binding aptamer. Several concentrations of thrombin in buffer solution were made, ranging from 1nM to 1?M. All the concentrations were detectable by the devices demonstrating that sub-nM concentrations may be monitored.

Allsop, T.; Nagel, D.; Neal, R.; Davies, E. M.; Mou, C.; Bond, P.; Rehman, S.; Kalli, K.; Webb, D. J.; Calverhouse, P.; Mascini, M.; Bennion, I.

2010-04-01

277

Surface plasmon-based infrared spectroscopy for cell biosensing  

NASA Astrophysics Data System (ADS)

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.

Yashunsky, Victor; Lirtsman, Vladislav; Zilbershtein, Alexander; Bein, Amir; Schwartz, Betty; Aroeti, Benjamin; Golosovsky, Michael; Davidov, Dan

2012-08-01

278

Surface Plasmon Resonance for Cell-Based Clinical Diagnosis  

PubMed Central

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

Yanase, Yuhki; Hiragun, Takaaki; Ishii, Kaori; Kawaguchi, Tomoko; Yanase, Tetsuji; Kawai, Mikio; Sakamoto, Kenji; Hide, Michihiro

2014-01-01

279

Derivation of thermokarst distribution based on climate and surface characteristics  

NASA Astrophysics Data System (ADS)

About one quarter of the northern hemisphere is covered by permafrost. Permafrost areas inherit a high amount of deposited soil organic carbon, which represents approximately 50% of the estimated global below-ground organic carbon pool and is more than twice the size of the current atmospheric carbon pool. A destabilization due to the expected amplitude of future Arctic climate warming would lead to a global-scale feedback mechanism. This feedback comprise interactions between snow, permafrost, hydrology, and ecosystems, which include altered energy and water fluxes between atmosphere and land surface. The representation of permafrost related processes in GCMs and ESMs is still rudimentary and needs to be extended to improve the climate model performance in high latitudes. In this sense thermokarst processes should be included into JSBACH, the land-surface component of MPI-ESM. Initially, a 1-D scheme of thermal dynamics will be implemented into JSBACH, which fits into very recent developments with regards to permafrost melting and freezing (T. Blome; Ekici et al., in prep.) and a dynamical wetland scheme (Stacke and Hagemann, 2012). Structural improvements and new parametrization of the model are required with regard to heat and water flow (physical processes) and carbon and nitrogen dynamics (bio-geochemical processes). The implementation of a thermokarst module is one task within the EU project PAGE21 and is a joint activity between MPI-M Hamburg and MPI-BGC Jena. Thermokarst changes are coupled thermal-hydrological processes, which lead to an enhanced thawing of ice-rich permafrost on local-to-regional scales, where the soil structure is characterized by segregated ice and ice-wedges. They result in severe consequences for soil structure, hydrology, and depletion of soil organic carbon. Thermokarst affected areas appear as a very uneven surface of hummocks and marshy hollows. The initial heat balance of the surface is disturbed by different trigger mechanisms, which cause the ground ice to melt and the soil to subside into depressions due to developing cavities in the interior. The depressions fill up with melting and precipitating water. Since deeper water bodies do not freeze up entirely, the annual mean surface temperature increases in the soil beneath. Therefore permafrost thawing is continued and depressions grow further due to soil subsidence and slope wash at the margins until a new soil surface heat balance is reached. Here I'd like to give a short overview and an introduction into the ongoing thermokarst process in the Arctic tundra. The main focus will be on investigating the actual distribution of thermokarst lakes in the high northern latitudes. The development of thermokarst lakes depends on soil parameters like ice content, surface temperature, soil texture as well as on climate states like monthly mean temperature, precipitation, winter snow depth. They contribute to the surface heat balance and may serve as a measure for thermokarst potential. Since thermokarst mechanism is a small-scale process of 10-1000m in spatial extent, it needs to be parametrized for GCM applications on ESM grid scale. Thus, we want to derive the thermokarst distribution as a function of climate and soil parameters.

Schöngaßner, Thomas; Hagemann, Stefan

2013-04-01

280

Orthogonal Least Square RBF Based Implicit Surface Reconstruction Methods  

Microsoft Academic Search

Two contributions on 3D implicit surface reconstruction from scattered points are presented in this paper. Firstly, least\\u000a square radial basis functions (LS RBF) are deduced from the conventional RBF formulations, which makes it possible to use\\u000a fewer centers when reconstruction. Then we use orthogonal least square (OLS) method to select significant centers from large\\u000a and dense point data sets. From

Xiaojun Wu; Michael Yu Wang; Qi Xia

2006-01-01

281

Engineering design optimization based on intelligent response surface methodology  

Microsoft Academic Search

An intelligent response surface methodology (IRSM) was proposed to achieve the most competitive metal forming products, in\\u000a which artificial intelligence technologies are introduced into the optimization process. It is used as simple and inexpensive\\u000a replacement for computationally expensive simulation model. In IRSM, the optimal design space can be reduced greatly without\\u000a any prior information about function distribution. Also, by identifying

Guo-hui Song; Yu Wu; Cong-xin Li

2008-01-01

282

Orthodontic bracket bonding with a plasma-arc light and resin-reinforced glass ionomer cement.  

PubMed

Developments in light-curing technology have led to the introduction of a plasma-arc light-curing unit that delivers high-intensity output for faster curing. The purposes of this study were to determine the shear bond strengths of light-cured resin-reinforced glass ionomer cement cured with a plasma-arc light-curing unit and to evaluate the durability of the resultant bond strength with thermal cycling. Comparisons were made between light-cured resin-reinforced glass ionomer cement and light-cured composite resin. Two light-curing units were used in this study: a plasma-arc light-curing unit and a conventional light-curing unit. The mean shear bond strengths of light-cured resin-reinforced glass ionomer cement with the plasma-arc and the conventional light-curing units were 20.3 MPa and 26.0 MPa, respectively. An analysis of variance showed no statistically significant differences between the plasma-arc and the conventional light-curing units. Light-cured resin-reinforced glass ionomer cement and light-cured composite resin demonstrated similar bond strengths and exhibited no statistical differences. There was no statistical difference in bond strength between the teeth that were thermal cycled and those that were not. Failure sites for the brackets bonded with light-cured resin-reinforced glass ionomer cement appeared to be predominantly at the bracket-adhesive interface. The SDs of light-cured composite resin were high for both light-curing units. Whereas the coefficients of variation for light-cured resin-reinforced glass ionomer cement ranged from 20% to 30%, those of light-cured composite resin ranged from 40% to 60%. The bond strength of light-cured resin-reinforced glass ionomer cement cured with either a conventional light-curing unit or a plasma-arc light-curing unit surpassed the clinically required threshold. The plasma-arc light-curing unit may be an advantageous alternative to the conventional light-curing unit for orthodontic bracket bonding with both light-cured resin-reinforced glass ionomer cement and light-cured composite resin. PMID:11455379

Ishikawa, H; Komori, A; Kojima, I; Ando, F

2001-07-01

283

SAR imaging simulation for an inhomogeneous undulated lunar surface based on triangulated irregular network  

Microsoft Academic Search

Based on the statistics of the lunar cratered terrain, e.g., population, dimension and shape of craters, the terrain feature\\u000a of cratered lunar surface is numerically generated. According to the inhomogeneous distribution of the lunar surface slope,\\u000a the triangulated irregular network (TIN) is employed to make the digital elevation of lunar surface model. The Kirchhoff approximation\\u000a of surface scattering is then

Wenzhe Fa; Feng Xu; Yaqiu Jin

2009-01-01

284

A silica gel based method for extracting insect surface hydrocarbons.  

PubMed

Here, we describe a novel method for the extraction of insect cuticular hydrocarbons using silica gel, herein referred to as "silica-rubbing". This method permits the selective sampling of external hydrocarbons from insect cuticle surfaces for subsequent analysis using gas chromatography-mass spectrometry (GC-MS). The cuticular hydrocarbons are first adsorbed to silica gel particles by rubbing the cuticle of insect specimens with the materials, and then are subsequently eluted using organic solvents. We compared the cuticular hydrocarbon profiles that resulted from extractions using silica-rubbing and solvent-soaking methods in four ant and one bee species: Linepithema humile, Azteca instabilis, Camponotus floridanus, Pogonomyrmex barbatus (Hymenoptera: Formicidae), and Euglossa dilemma (Hymenoptera: Apidae). We also compared the hydrocarbon profiles of Euglossa dilemma obtained via silica-rubbing and solid phase microextraction (SPME). Comparison of hydrocarbon profiles obtained by different extraction methods indicates that silica rubbing selectively extracts the hydrocarbons that are present on the surface of the cuticular wax layer, without extracting hydrocarbons from internal glands and tissues. Due to its surface specificity, efficiency, and low cost, this new method may be useful for studying the biology of insect cuticular hydrocarbons. PMID:22327277

Choe, Dong-Hwan; Ramírez, Santiago R; Tsutsui, Neil D

2012-02-01

285

Linseed Oil-Based Concrete Surface Treatment -for Building and Highway Structures in  

E-print Network

, Linseed Oil-Based Concrete Surface Treatment -for Building and Highway Structures in Hong Kong Y using jour Canadian linseed oil- based sealants on concrete specimens madejrom G30120 and G45120 Keywords: Unseed Oil, Concrete Surface Treatment, Salt Spray Resistance, Carbonation, Bond Strength, Ultra

286

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

E-print Network

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

Toronto, University of

287

March Madness and Filling out an NCAA Tournament Bracket: The Method of Using Colley Matrix and Laplace Theorem  

E-print Network

popular college sports series. Especially when the top sixty four Division I man basketball teams go to list the college football ranking with other annexed theorems are depicted and show skills and tips, offers $1 billion to anyone with the perfect March Madness bracket. According to the Nielsen Media

Marzuola, Jeremy

288

Effect of a self-etch primer\\/adhesive on the shear bond strength of orthodontic brackets  

Microsoft Academic Search

Conventional adhesive systems use 3 different agents (an enamel conditioner, a primer solution, and an adhesive resin) during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single product. Combining conditioning and priming saves time and should be more cost-effective

Samir E. Bishara; Leigh VonWald; John F. Laffoon; John J. Warren

2001-01-01

289

Chromium boron surfaced nickel-iron base alloys  

NASA Technical Reports Server (NTRS)

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.

Rashid, James M. (Inventor); Friedrich, Leonard A. (Inventor); Freling, Melvin (Inventor)

1984-01-01

290

Highly directional liquid surface wave source based on resonant cavity  

NASA Astrophysics Data System (ADS)

By placing a point source inside a resonant cavity structure, we present a method to realize a highly directional liquid surface wave source. The resonant cavity is surrounded by two slabs of different thickness, with each slab consisting of a finite square array of rigid cylinders standing vertically in the liquid. It is shown that more than 68% of the total energy is emitted out along the normal directions of the cavity within a very narrow angular range. At the resonant frequency, narrow emission pattern with half-power angular width of only several degrees is obtained.

Mei, Jun; Qiu, Chunyin; Shi, Jing; Liu, Zhengyou

2009-08-01

291

Broadband metamaterial absorber based on coupling resistive frequency selective surface.  

PubMed

We report the design, fabrication, and measurement of a broadband metamaterial absorber, which consists of lossy frequency selective surface (FSS) and a metallic ground plane separated by a dielectric layer. The compact single unit cell of the FSS contains crisscross and fractal square patch which couple with each other. Both qualitative analysis by equivalent circuit and accurate numeric calculation show that the coupling between the crisscross and the fractal square patch can enhance the bandwidth with the reflectivity below -10dB in the frequency range of 2-18GHz by producing a third absorption null. In the end, the designed absorber was realized by experiment. PMID:22418224

Sun, LiangKui; Cheng, HaiFeng; Zhou, YongJiang; Wang, Jun

2012-02-13

292

An Interacting Gauge Field Theoretic Model for Hodge Theory: Basic Canonical Brackets  

NASA Astrophysics Data System (ADS)

We derive the basic canonical brackets amongst the creation and annihilation operators for a two (1 + 1)-dimensional (2D) gauge held theoretic model of an interacting Hodge theory where a U(1) gauge field (A?) is coupled with the fermionic Dirac fields (? and bar psi). In this derivation, we exploit the spin-statistics theorem, normal ordering and the strength of the underlying six infinitesimal continuous symmetries (and the concept of their generators) that are present in the theory. We do not use the definition of the canonical conjugate momenta (corresponding to the basic fields of the theory) anywhere in our whole discussion. Thus, we conjecture that our present approach provides an alternative to the canonical method of quantization for a class of gauge field theories that are physical examples of Hodge theory where the continuous symmetries (and corresponding generators) provide the physical realizations of the de Rham cohomological operators of differential geometry at the algebraic level.

R., Kumar; Gupta, S.; R. P., Malik

2014-06-01

293

Automated Proofs using Bracket Algebra with Cinderella and OpenMath  

E-print Network

This paper describes the results of a project intended to make it possible to put forward geometrical theorems by pointing and clicking, and then obtain a proof for that theorem automatically. This goal was achieved by adding various options to Cinderella [1], a computer program with which one can create geometrical configurations. Its internal ‘Randomized prover ’ is able to discover theorems automatically. In the project the functionality was added to find proofs for these theorems with the aid of the computer algebra package GAP [9]. Communication between these two programs and the various steps in generating the proof is done by means of OpenMath [5, 7]. The proofs are represented by bracket calculations as proposed in [8].

Dan Roozemond

294

Adhesion promoters, their effect on the bond strength of metal brackets.  

PubMed

There are occasions where it is desired to increase the bond strengths of no-mix adhesives. Noncompliant patients and hypocalcified and fluorosed tooth enamel require higher bond strengths than usually obtained. It was the purpose of this investigation to study the effects of adhesion promoters to increase bond strengths. In vitro shear bond strengths that use the Instron machine (Instron Corp., Canton, Mass.) and thermocycling methods indicate the bond strengths of a no-mix adhesive bonding 80 gauge metal mesh brackets can be significantly improved through the following techniques: control (MPa 9.0), sandblasting (MPa 10.8), sandblasting and silanating (MPa 11.9), Rocatec system (MPa 10.8), Kulzer "silicoating" (MPa 13.2), and adhesion promoters--Megabond--(MPa 13.3). These adhesive promoters have been and are clinically being tested with promising results. PMID:7661138

Newman, G V; Newman, R A; Sun, B I; Ha, J L; Ozsoylu, S A

1995-09-01

295

Rough surface scattering results based on bandpass autocorrelation forms  

NASA Technical Reports Server (NTRS)

Surface-height autocorrelation forms such as Gaussian and exponential are often used in studies of near-normal incidence rough-surface scattering. Such models require the existence of a constant, or DC, value in the spectrum. The consequences of autocorrelation forms that correspond to spectral processes that are essentially bandpass in nature are examined. One such process is that of ocean wind waves. In this case, the spectral components do not extend down to zero frequency. The physical optics backscatter theory is reexamined relative to such autocorrelation functions. Experimental results obtained from a wavetank are compared to the autocorrelation model used in the analysis. The analysis indicates that Gaussian correlation length or mean-square slope is not an appropriate parameter for narrowband conditions and that significant slope is a more relevant parameter. Inherent in the deep-phase assumption is some form of slope dependency. The analysis given (and variants thereof) can be used to provide insight into the physical effects of separate spectral components and of spectral directionality.

Miller, Lee S.; Parsons, Chester L.

1990-01-01

296

Reflectance-Based Sensor Validation Over Ice Surfaces  

NASA Technical Reports Server (NTRS)

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.

Jaross, Glen; Dodge, James C. (Technical Monitor)

2003-01-01

297

Microstructure and surface properties of lignocellulosic-based activated carbons  

NASA Astrophysics Data System (ADS)

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.

González-García, P.; Centeno, T. A.; Urones-Garrote, E.; Ávila-Brande, D.; Otero-Díaz, L. C.

2013-01-01

298

Reconstruction of Two-Dimensional Randomly Rough Surfaces Based on Bidirectional Reflectance Distribution Function  

NASA Astrophysics Data System (ADS)

This article presents an inverse method for reconstructing two-dimensional randomly rough surfaces based on the available (experimental or given) data of the bidirectional reflectance distribution function (BRDF). The Maxwell's equations of electromagnetic waves are applied to describe the light scattering process of rough surfaces by accounting for the near-field effect. Such a forward problem is numerically solved with the finite-difference time-domain algorithm. The inverse scattering problem of reconstructing the surface profile is handled by means of an optimization technique—the particle swarm optimizer algorithm. As an example, reconstruction of a Gaussian rough surface is conducted based on the experimental data of BRDFs. The retrieved results of the surface profile are compared with those measured by atomic force microscopy from the samples, which shows that the reconstruction algorithm can provide the credible prediction of surface profiles. The reconstruction approach studied in this study can make reliable predictions of the actual or required surface profiles.

Xuan, Yimin; Han, Yuge; Zhou, Yue

2013-03-01

299

Multivariate Tensor-based Morphometry on Surfaces: Application to Mapping Ventricular Abnormalities in HIV/AIDS  

PubMed Central

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

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

300

Inconsistencies in surface anatomy: The need for an evidence-based reappraisal.  

PubMed

Accurate surface anatomy is a key component of safe clinical practice. But how consistent are modern clinical and surface anatomy texts in their reporting of common surface anatomy landmarks? Thirteen popular texts in common use were analyzed in detail: one clinical and anatomical reference text; seven clinical anatomy texts; two surface anatomy texts; and three clinical examination texts. Content relating to surface anatomy was reviewed, summarized, and assessed for consistency. Four main findings emerged: (i) there are numerous inconsistencies in clinically important surface markings (e.g., the femoral artery in the groin, superficial and deep inguinal rings, and accessory nerve in the posterior triangle), including inconsistencies within some texts; (ii) there is a consensus on many surface markings, e.g., the spleen and termination of the spinal cord; (iii) few texts address variation in surface anatomy related to age, sex, body mass, posture, respiration, and ethnicity; and (iv) the three standard clinical examination texts included in this review contain comparatively little surface anatomy. Seven surface anatomy landmarks were redefined within an evidence-based framework: termination of the spinal cord, supracristal plane, base of the appendix, renal length, the deep inguinal ring, the femoral artery in the groin, and the accessory nerve in the posterior triangle of the neck. An evidence-based framework is essential if surface anatomy is to be accurate and clinically relevant. PMID:20830790

Hale, Samuel J M; Mirjalili, S Ali; Stringer, Mark D

2010-11-01

301

Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial  

PubMed Central

Objective: To investigate the effect of bracket–ligature combination on the amount of orthodontic space closure over three months. Design: Randomized clinical trial with three parallel groups. Setting: A hospital orthodontic department (Chesterfield Royal Hospital, UK). Participants: Forty-five patients requiring upper first premolar extractions. Methods: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick® low friction elastomeric ligatures; (3) Damon 3MX® passive self-ligating brackets. Space closure was undertaken on 0·019×0·025-inch stainless steel archwires with nickel–titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period. Results: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P?=?0·718). Conclusion: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response. PMID:23794696

Wong, Henry; Collins, Jill; Tinsley, David; Sandler, Jonathan; Benson, Philip

2013-01-01

302

Simulation of a Lunar Surface Base Power Distribution Network for the Constellation Lunar Surface Systems  

NASA Technical Reports Server (NTRS)

The Lunar Surface Power Distribution Network Study team worked to define, breadboard, build and test an electrical power distribution system consistent with NASA's goal of providing electrical power to sustain life and power equipment used to explore the lunar surface. A testbed was set up to simulate the connection of different power sources and loads together to form a mini-grid and gain an understanding of how the power systems would interact. Within the power distribution scheme, each power source contributes to the grid in an independent manner without communication among the power sources and without a master-slave scenario. The grid consisted of four separate power sources and the accompanying power conditioning equipment. Overall system design and testing was performed. The tests were performed to observe the output and interaction of the different power sources as some sources are added and others are removed from the grid connection. The loads on the system were also varied from no load to maximum load to observe the power source interactions.

Mintz, Toby; Maslowski, Edward A.; Colozza, Anthony; McFarland, Willard; Prokopius, Kevin P.; George, Patrick J.; Hussey, Sam W.

2010-01-01

303

Surface-enhanced Raman spectroscopy based on ordered nanocap arrays  

NASA Astrophysics Data System (ADS)

We fabricated the Ag cap array for surface-enhanced Raman scattering (SERS) by Ag deposition onto two dimensional polystyrene colloid sphere templates, and 4-mercaptopyridine (4-MPy) was used as the probing molecule. When the colloids with different size were chosen as the substrate for 20 nm Ag deposition, the film on 100 nm colloids gave the significant enhancement. SERS intensity increased with the increase of Ag thickness. When 20 nm Ag film was coated by Ta, the SERS signals decreased with the increase of Ta thickness, indicating the main effect from the top of cap structure. When Co layer was added under the Ag film, the SERS intensity decreased with the increase of Co thickness because the Co layer affects electromagnetic and plasmon resonance.

Wang, Y. X.; Liu, S. S.; Gao, W. T.; Li, W.; Zhang, Y. J.; Yang, J. H.

2012-10-01

304

The localized surface plasmon resonances based on a Bragg reflector  

NASA Astrophysics Data System (ADS)

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.

Wang, Jie; Liu, Yumin; Yu, Zhongyuan; Ye, Chunwei; Lv, Hongbo; Shu, Changgan

2014-09-01

305

A Fast Terahertz Spectrometer Based on Frequency Selective Surface Filters  

NASA Astrophysics Data System (ADS)

We present a fast spectrometer working in the 0.7-4.8 THz range. Broadband radiation from a blackbody source is focused first on a rotating silicon wafer, whose surface was patterned with 18 metal band-pass filters, then on the sample under test and finally is detected by a superconducting microbolometer with microsecond time constant. The bolometer sensor is coupled to a spiral antenna whose frequency band matches the spectral range of the filters. The spectral resolution is set by the filters quality factor of about 3. A dynamic range of 100 and a S/N ratio of 20 are achieved by integrating for less than 10 second. The detector can operate up to 6 K in a closed-cycle cooler, hence making the present apparatus suitable for building up a simple terahertz video-rate spectrometer.

Carelli, P.; Chiarello, F.; Cibella, S.; Di Gaspare, A.; Leoni, R.; Ortolani, M.; Torrioli, G.

2012-05-01

306

Multilayer magnetostrictive structure based surface acoustic wave devices  

NASA Astrophysics Data System (ADS)

This study addresses the experimental and theoretical investigations of guided elastic waves propagation in piezo-magnetic multi-layered structure. The structure is composed of a 20×TbCo2(5nm)/FeCo(5nm) nanostructured multi-layer deposited between two Aluminum (Al) Inter-Digitals Transducers forming a surface acoustic wave delay line, on a Y-cut LiNbO3 substrate. We compare the calculated and measured phase velocity variation under the action of the external magnetic field orientation and magnitude. We find quantitative agreement between the measured and modeled phase velocity shift for all external magnetic field configurations (hard axis and easy axis) and for different shape modes of elastic waves at their first and third harmonic operation frequencies. The shear horizontal mode exhibits a maximum phase velocity shift close to 20% for a ratio close to 1 between magneto-elastic film thickness and wavelength.

Zhou, H.; Talbi, A.; Tiercelin, N.; Bou Matar, O.

2014-03-01

307

[A lidocaine base for surface anesthesia of the tympanic membrane].  

PubMed

An anatomical study was conducted to determine the effects of 10% lidocain base (dissolved in DMSO) on the structure of the tympanic membrane. Survival times ranged from 1 day to 3 months. Membranes were embedded in plastic and cut in semithin sections. Within 1 and 3 days mild swelling of the epithelium was seen; 1 month after treatment the connective tissue layers of the lamina propria were severely hyperplastic. 2 months after lidocain-Base application additional collagen fibres, loosely packed and less regularly, appeared in the submucosal connective tissue layer. However, normal appearance of the drums was noticeable after 3 months survival. PMID:3210864

Strutz, J; Zöllner, C

1988-07-01

308

Increased reactivity and in vitro cell response of titanium based implant surfaces after anodic oxidation.  

PubMed

In the quest for improved bone growth and attachment around dental implants, chemical surface modifications are one possibility for future developments. The biological properties of titanium based materials can be further enhanced with methods like anodic polarization to produce an active rather than a passive titanium oxide surface. Here we investigate the formation of hydroxide groups on sand blasted and acid etched titanium and titanium-zirconium alloy surfaces after anodic polarization in an alkaline solution. X-ray photoelectron spectroscopy shows that the activated surfaces had increased reactivity. Furthermore the activated surfaces show up to threefold increase in OH(-) concentration in comparison to the original surface. The surface parameters Sa, Sku, Sdr and Ssk were more closely correlated to time and current density for titanium than for titanium-zirconium. Studies with MC3T3-E1 osteoblastic cells showed that OH(-) activated surfaces increased mRNA levels of osteocalcin and collagen-I. PMID:23912792

Walter, M S; Frank, M J; Sunding, M F; Gómez-Florit, M; Monjo, M; Bucko, M M; Pamula, E; Lyngstadaas, S P; Haugen, H J

2013-12-01

309

Laser-based dynamic surface tension detection for liquid chromatography by probing a repeating drop radius  

Microsoft Academic Search

Modifications to the design of the time-based dynamic surface tension detection (DSTD) system are reported. Both a theoretical and experimental evaluation of the modifications are presented to demonstrate a reduction in flow-rate fluctuation derived systematic noise. The instrument-based limit of detection in relative surface tension change for the improved volume-based DSTD is determined to be 0.15% (3 × root-mean-square noise)

Lawrence R. Lima; Robert E. Synovec

1995-01-01

310

CAD system for footwear design based on whole real 3D data of last surface  

NASA Astrophysics Data System (ADS)

Two major parts of application of CAD in footwear design are studied: the development of last surface; computer-aided design of planar shoe-template. A new quasi-experiential development algorithm of last surface based on triangulation approximation is presented. This development algorithm consumes less time and does not need any interactive operation for precisely development compared with other development algorithm of last surface. Based on this algorithm, a software, SHOEMAKERTM, which contains computer aided automatic measurement, automatic development of last surface and computer aide design of shoe-template has been developed.

Song, Wanzhong; Su, Xianyu

2000-10-01

311

Surfaces and interfaces in polymer-based electronics  

Microsoft Academic Search

Research on electronics applications such as light-emitting devices for flat-panel displays, transistors, sensors and even solid state lasers based on conducting polymers is presently under way and in some cases has reached the stage of prototype production. The mechanisms for charge injection and conduction in these materials are being studied, as are the physics of luminescence and its quenching. Lately,

M. Fahlman; W. R. Salaneck

2002-01-01

312

Research on optical surface quality online monitoring based on support vector machine  

NASA Astrophysics Data System (ADS)

The interference of grinding wheel and optic surface during grinding process causes numerous acoustic emission (AE) phenomena. AE signals are competent for monitoring the quality of the ground surface. A quality prediction model of grinding optics is established based on support vector machine (SVM). Some time domain characteristics of AE signals are chosen as the input vectors. And surface roughness (Ra) and surface shape accuracy (P-V) are the output vectors, respectively. The experiment results show that the model can accurately predict the surface quality of the optics during grinding.

Bi, Guo; Sun, Zhiji; Zhang, Dongxu

2014-08-01

313

Moving Surface Spline Interpolation Based on Green’s Function  

Microsoft Academic Search

Some commonly used interpolation algorithms are analyzed briefly in this paper. Among all of the methods, biharmonic spline\\u000a interpolation, which is based on Green’s function and proposed by Sandwell, has become the mainstream method for its high\\u000a precision, simplicity and flexibility. However, the minimum curvature method has two flaws. First, it suffers from undesirable\\u000a oscillations between data points, which is

Xingsheng Deng; Zhong-an Tang

2011-01-01

314

A Comparison of Shear Bond Strengths of Metal and Ceramic Brackets using Conventional Acid Etching Technique and Er:YAG Laser Etching  

PubMed Central

Background and aims. The aim of this study was to compare shear bond strength (SBS) of metal and ceramic brackets bonded to enamel using acid versus Er:YAG laser etching. Materials and methods. Eighty premolars were divided into 4 groups: AM (acid etching/ metal brackets), AC (acid etching/ ceramic brackets), LM (laser etching/ metal brackets) and LC (laser etching/ ceramic brackets). Enamel condition-ing was done using acid in AC and AM and Er:YAG laser in LC and LM. Brackets were debonded with a Dartec machine and the SBSs were determined. Adhesive remnant index was evaluated under a stereomicroscope. Two additional teeth were conditioned with acid and laser for scanning electron microscopy examination. Comparisons of SBS value were done by ANOVA test. Results. statistical analyses showed that SBSs of acid groups were significantly higher than that of laser groups, but dif-ferences between SBS values of AC/ AM and LC/LM were not significant. SEM examination revealed different etching pattern. Conclusion. Low power Er:YAG laser etching offers clinically acceptable SBS which besides its other superiorities to acid etching can be an appropriate alternative for bonding of ceramic brackets. PMID:25024836

Yassaei, Sogra; Fekrazad, Reza; Shahraki, Neda; Goldani Moghadam, Mahdjoube

2014-01-01

315

Fragment-based screening using surface plasmon resonance technology.  

PubMed

Surface plasmon resonance (SPR) technology has emerged as a new and powerful technique to investigate the interaction between low-molecular-weight molecules and target proteins. In the present work, the authors assemble from a large compound collection a library of 2226 molecules (fragments having low molecular weights between 100 and 300 Da) to screen them for binding to chymase, a serine protease. Both the active chymase and a zymogen-like form of the protein were used in parallel to distinguish between specific and unspecific binding. The relative ligand-binding activity of the immobilized protein was periodically measured with a reference compound. The screening experiments were performed at 25 degrees C at a fragment concentration of 200 microM in the presence of 2% DMSO. Applying the filter cascade, affinity-selectivity-competition (competition with reference compounds and cross-competition with fragments), 80 compounds show up as positive screening hits. Competition experiments between fragments show that they bind to different parts of the active site. Of 36 fragments co-crystallized for X-ray studies, 12 could be located in the active site of the protein. These results validate the authors' library and demonstrate that the application of SPR technology as a filter in fragment screening can be achieved successfully. PMID:19403917

Perspicace, Samantha; Banner, David; Benz, Jörg; Müller, Francis; Schlatter, Daniel; Huber, Walter

2009-04-01

316

A regression-based statistical correction of mesoscale simulations for near-surface wind speed using remotely sensed surface observations  

NASA Astrophysics Data System (ADS)

Wind speed is an important meteorological variable for various scientific communities. In this study, numerical mesoscale simulations were performed over the Republic of Korea in 2006, to produce wind information distributed homogeneously with space. Then, an attempt was made to statistically correct the simulated nearsurface wind speed using remotely sensed surface observations. The weak wind season (WWS, from May to October) and strong wind season (SWS, from November to April) were classified on the basis of the annual mean wind speed. Although the spatial features and monthly variation pattern of the near-surface wind speed were reasonably simulated in the Weather Research and Forecasting (WRF) model, the simulations overestimated the observed values. To correct the simulated wind speeds, a regression-based statistical algorithm with different constants and coefficients for WWS and SWS was developed using match-up datasets of wind observations and satellitederived variables (land surface temperature and normalized difference water index). The corrected wind speeds showed reasonable performance for both WWS and SWS with respect to observed values. The monthly variation in the corrected wind speeds over the Republic of Korea also matched better with observations throughout the year, within a monthly bias range of approximately ± 0.2 m s-1. The proposed algorithm using remotely sensed surface observations may be useful for correcting simulated near-surface wind speeds and improving the accuracy of wind assessments over the Republic of Korea.

Kim, Do-Yong; Kim, Jin-Young; Kim, Jae-Jin

2012-11-01

317

Effect of archwire size and material on the resistance to sliding of self-ligating brackets with second-order angulation in the dry state.  

PubMed

When paired with a particular self-ligating bracket design, the material and the geometric characteristics of an archwire influence its resistance to sliding. Four designs of self-ligating brackets (1 with a slide, 3 with clips) were coupled with 5 types of archwires: 14-mil round austenitic nickel-titanium, 16 x 22-mil rectangular austenitic nickel-titanium, 19 x 25-mil rectangular austenitic nickel-titanium, 19 x 25-mil rectangular martensitic nickel-titanium, and 19 x 25-mil rectangular stainless steel. The resistance to sliding (RS) of each archwire-bracket couple was measured at second-order angles between -9 degrees and 9 degrees. Interbracket distances of 8 and 18 mm between the test bracket and the adjacent brackets mimicked closure of a premolar extraction. When clearance exists, the RS is negligible for self-ligating brackets with slides coupled to any size of wire as well as for those with clips when coupled to wires that do not contact the clip. Once the wire attains a certain size and contacts the clip, the RS depends on the archwire size, the bracket design, and the materials of the couple. When coupled with the 16 x 22-mil wire, the brackets with clips applied normal forces ranging from a low of 5.6 centi-Newtons (cN) (1 cN = 1 g) to a high of 230 cN. When clearance disappears, the RS increased proportionally with the second-order angle. The 19 x 25-mil stainless steel wires, which were the most stiff, increased at rates between 75 and 84 cN/degree; the 14-mil austenitic nickel-titanium wires, which were the least stiff, increased at rates from 2.6 to 5.4 cN/degree. The treatment objectives for a particular patient at a specific stage should determine the appropriate archwire-bracket combination. PMID:12226612

Thorstenson, Glenys A; Kusy, Robert P

2002-09-01

318

Version 2 Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF2)  

NASA Technical Reports Server (NTRS)

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.

Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.; Shie, Chung-Lin; Starr, David O'C. (Technical Monitor)

2002-01-01

319

Excitation of surface electromagnetic waves in a graphene-based Bragg grating  

PubMed Central

Here, we report the fabrication of a graphene-based Bragg grating (one-dimensional photonic crystal) and experimentally demonstrate the excitation of surface electromagnetic waves in the periodic structure using prism coupling technique. Surface electromagnetic waves are non-radiative electromagnetic modes that appear on the surface of semi-infinite 1D photonic crystal. In order to fabricate the graphene-based Bragg grating, alternating layers of high (graphene) and low (PMMA) refractive index materials have been used. The reflectivity plot shows a deepest, narrow dip after total internal reflection angle corresponds to the surface electromagnetic mode propagating at the Bragg grating/air boundary. The proposed graphene based Bragg grating can find a variety of potential surface electromagnetic wave applications such as sensors, fluorescence emission enhancement, modulators, etc. PMID:23071901

Sreekanth, Kandammathe Valiyaveedu; Zeng, Shuwen; Shang, Jingzhi; Yong, Ken-Tye; Yu, Ting

2012-01-01

320

Low dimensional self-organization of DNA-base molecules on Cu(111) surfaces  

Microsoft Academic Search

DNA base molecules form novel low dimensional superstructures on Cu(111) surfaces through hydrogen bonding among molecules and through their epitaxial nature on the surface. Scanning tunneling microscope images have revealed that the chemical inertness of the Cu(111) substrate allows the molecules to diffuse over the surface to spontaneously self-assemble themselves into their own unique structure: adenine into one-dimensional molecular chains,

Tomoji Kawai; Hiroyuki Tanaka; Takaomi Nakagawa

1997-01-01

321

Evaluation of Surface Free Energy of Various Fruit Epicarps Using Acid–Base and Zisman Approaches  

Microsoft Academic Search

Surface free energy (SFE; ?\\u000a SV) of 16 fruit epicarps present on the Chilean market was calculated by two approaches: the acid–base and Zisman. The results\\u000a show that the fruit epicarps were low surface energy since the magnitude of ?\\u000a SV falls within a narrow range, between 37 and 44 mJ m???2. Zisman approach gave a critical surface tension values, ?\\u000a cr

Patricia Velásquez; Olivier Skurtys; Javier Enrione; Fernando Osorio

322

Evaluating Surface Trajectory-Based Operations concepts through a human-in-the-loop simulation  

Microsoft Academic Search

Surface Trajectory-Based Operations (STBO) is a concept and research area for improving the safety and efficiency of surface operations and is envisioned as part of the Federal Aviation Administration's (FAA's) Next Generation Air Transportation System (NextGen). STBO provides a concept of operating the surface in the mid — and far-term that includes automated decision support tools to assist air traffic

Emily Stelzer; Raymond M. Stanley; Kathryn Klein Shepley

2011-01-01

323

Enhanced output power in GaN-based LEDs with naturally textured surface grown by MOCVD  

Microsoft Academic Search

GaN-based light-emitting diodes (LEDs) with naturally textured surfaces grown by MOCVD were demonstrated. In this study, a growth-interruption step and a surface treatment using biscyclopentadienyl magnesium (CP2Mg) were simultaneously performed to form a plurality of nuclei sites on the surface of a p-type cladding layer, and then a p-type contact layer was grown on the p-type cladding layer, so as

C. M. Tsai; J. K. Sheu; W. C. Lai; Y. P. Hsu; P. T. Wang; C. T. Kuo; C. W. Kuo; S. J. Chang; Y. K. Su

2005-01-01

324

Semiempirical pseudopotential approach for nitride-based nanostructures and ab initio based passivation of free surfaces  

NASA Astrophysics Data System (ADS)

We present a semiempirical pseudopotential method based on screened atomic pseudopotentials and derived from ab initio calculations. This approach is motivated by the demand for pseudopotentials able to address nanostructures, where ab initio methods are both too costly and insufficiently accurate at the level of the local density approximation, while mesoscopic effective-mass approaches are inapplicable due to the small size of the structures along, at least, one dimension. In this work, we improve the traditional pseudopotential method by a two-step process: First, we invert a set of self-consistently determined screened ab initio potentials in wurtzite GaN for a range of unit-cell volumes, thus determining spherically symmetric and structurally averaged atomic potentials. Second, we adjust the potentials to reproduce observed excitation energies. We find that the adjustment represents a reasonably small perturbation over the potential, so that the ensuing potential still reproduces the original wave functions, while the excitation energies are significantly improved. We furthermore deal with the passivation of the dangling bonds of free surfaces which is relevant for the study of nanowires and colloidal nanoparticles. We present a methodology to derive passivant pseudopotentials from ab initio calculations. We apply our pseudopotential approach to the exploration of the confinement effects on the electronic structure of GaN nanowires.

Molina-Sánchez, A.; García-Cristóbal, A.; Bester, G.

2012-11-01

325

Hybrid dimension based modeling of part surface topography and identification of its characteristic parameters  

NASA Astrophysics Data System (ADS)

Since the complete description of complex part surface is difficult to achieve using the existing integral dimensional or fractal dimensional approaches, the novel concept of hybrid dimension and its modeling method of part surface topography are proposed in this paper. The hybrid dimensional model of part surface topography is established based on the deflection method of surface correlation coefficient, which associates the integral dimensional and fractal dimensional surface topographies. Superimposing the normalized fractal dimensional surface altitude field on the B-spline surface, the hybrid dimensional model can express the integral dimensional information of part surface in macro level, and the fractal dimensional detail in micro level. And the correlation of part surface topographies among different scales and different dimensions is established by the Hybrid Dimensional Surface Correlation Coefficient. Moreover, the characteristic parameter identification method for the hybrid dimensional model of part surface topography is proposed. The component information of integral dimension and fractal dimension is separated and extracted by wavelet analysis, and hybrid dimensional characteristic parameters are identified by the generalized surface structure function method and the roughness mapping method. Finally, the proposed method is applied to design and manufacture of turbo expander.

Qiu, Chan; Liu, Zhenyu; Bu, Wanghui; Tan, Jianrong

2012-07-01

326

3D shape measurement of optical free-form surface based on fringe projection  

NASA Astrophysics Data System (ADS)

Present a novel method of 3D shape measurement of optical free-from surface based on fringe projection. A virtual reference surface is proposed which can be used to improve the detection efficiency and realize the automation of measuring process. Sinusoidal fringe patterns are projected to the high reflected surface of the measured object. The deflection fringe patterns that modulated by the object surface are captured by the CCD camera. The slope information can be obtained by analyzing the relationship between the phase deflectometry and the slope of the object surface. The wave-front reconstruction method is used to reconstruct the surface. With the application of fringe projection technology the accuracy of optical free-form surfaces measurement could reach the level of tens of micrometer or even micrometer.

Li, Shaohui; Liu, Shugui; Zhang, Hongwei

2011-05-01

327

Ground-Based Microwave Radiometer Measurements over Various Surface Covers  

NASA Technical Reports Server (NTRS)

Microwave brightness temperatures were measured over a young wheat crop of varying canopy density during the First NOPEX Concentrated Field Effort near Uppsala, Sweden. Measurements were made with a portable ground-based microwave radiometer system at a frequency of 1.4 GHz. The brightness temperature at each wavelength was measured at horizontal and vertical polarization, and at incidence angles ranging from nadir to 60 degrees. Three measuring sequences were made; at full canopy, after the partial harvest, and of the bare soil. Supporting data such as soil and canopy temperature, soil moisture, other soil physical properties, and canopy biomass were also collected. Preliminary results of some of the field measurements and comparisons with theoretical calculations are presented.

Owe, Manfred; deRuiter, Jan; Gouweleeuw, Ben; vandeGriend, Adriaan

1997-01-01

328

Space-based detection of wetlands' surface water level changes from L-band SAR interferometry  

E-print Network

Space-based detection of wetlands' surface water level changes from L-band SAR interferometry�1996 reveals detectable surface changes in the Everglades wetlands. Although our study is limited to south Florida it has implication for other large-scale wetlands, because south Florida wetlands have diverse

Amelung, Falk

329

3D MHD free surface fluid flow simulation based on magnetic-field induction equations  

E-print Network

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

Abdou, Mohamed

330

3D MHD Free Surface Fluid Flow Simulation Based on Magnetic-Field Induction Equations  

E-print Network

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

California at Los Angeles, University of

331

Water Research 38 (2004) 33313339 Testing a surface tension-based model to predict the salting  

E-print Network

Water Research 38 (2004) 3331­3339 Testing a surface tension-based model to predict the salting out associated with transferring solutes from water to a salt solution to the difference in surface tensions]. With respect to inorganic salts, numerous researchers have reported that the presence of ionic species in water

Herbert, Bruce

332

Structural and Functional Analyses of Human Cerebral Cortex Using a Surface-Based Atlas  

E-print Network

Structural and Functional Analyses of Human Cerebral Cortex Using a Surface-Based Atlas D. C. Van of human cerebral cortex using surface recon- structions and cortical flat maps of the left and right hemi mon- key cerebral cortex indicate significant differences as well as many similarities in the relative

Van Essen, David

333

Tangible display systems: direct interfaces for computer-based studies of surface appearance  

Microsoft Academic Search

When evaluating the surface appearance of real objects, observers engage in complex behaviors involving active manipulation and dynamic viewpoint changes that allow them to observe the changing patterns of surface reflections. We are developing a class of tangible display systems to provide these natural modes of interaction in computer-based studies of material perception. A first-generation tangible display was created from

Benjamin A. Darling; James A. Ferwerda

2010-01-01

334

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

E-print Network

iii ABSTRACT Improving Chemical Aqueous Based Intervention Methods for Microorganism Elimination from Fresh Produce Surfaces. (December 2004) Alex Frank Puerta-Gomez, B.S., Universidad Nacional Agraria La Molina Chair of Advisory Committee: Dr... Results and Discussion................................................................... 12 Survival of S. Typhimurium LT2 on different produce surfaces after different storage times .................. 12 Attachment of S...

Puerta-Gomez, Alex Frank

2006-04-12

335

Microstructured Surfaces on LiTaO $_{3}$Based Pyroelectric Infrared Detectors  

Microsoft Academic Search

Reflections of the incident radiation from the sensor surface are a major problem in enhancing the performance of pyroelectric infrared detectors. This paper reports on the approach to reduce these reflections by patterning the sensor surface of lithium tantalate (LiTaO )-based infrared detectors with subwavelength structures. These structures provide a better refractive index matching from air to sensitive material and,

Andreas Finn; Marco Schossig; Volkmar Norkus; Gerald Gerlach

2011-01-01

336

FEM-Based Surface Wave Multimixed-Path Propagator and Path Loss Predictions  

Microsoft Academic Search

A finite element method (FEM)-based surface wave propagation prediction simulator is developed. The simulator is tested and calibrated against analytical ray-mode models that also take into account the Millington recovery effects. It successfully calculates path losses over multimixed propagation paths at MF and HF frequency bands where the surface wave contribution is significant.

Gkhan Apaydin; Levent Sevgi

2009-01-01

337

A Collision Avoidance Algorithm Based on the Virtual Target Approach for Cooperative Unmanned Surface Vehicles  

E-print Network

A Collision Avoidance Algorithm Based on the Virtual Target Approach for Cooperative Unmanned, developed for Unmanned Surface Vehicle multi- agent frameworks. The proposed collision avoidance procedure- ment of multi-agent systems, where a number of Unmanned Surface Vehicles (USVs) cooperates in a common

Paris-Sud XI, Université de

338

An explicit surface-potential-based MOSFET model for circuit simulation  

Microsoft Academic Search

In this paper, a compact MOSFET model based on terms of surface potential is presented. An explicit approximate relation for surface potential as a function of terminal voltages is developed. The resulting model combines the accuracy of implicit single-piece models and the short calculation time of regional models. A comparison with measured data shows that the model gives an accurate

Ronald van Langevelde; François M Klaassen

2000-01-01

339

PSP: An Advanced Surface-Potential-Based MOSFET Model for Circuit Simulation  

Microsoft Academic Search

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

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

340

Intelligent Balloon: A Subdivision-Based Deformable Model For Surface Reconstruction Of Arbitrary Topology  

E-print Network

Intelligent Balloon: A Subdivision-Based Deformable Model For Surface Reconstruction Of Arbitrary Balloon---which is capable of recovering arbitrary, complicated shape geometry as well as its unknown topology simultaneously. Our Intelligent Balloon is a parameterized subdivision surface whose geometry

Qin, Hong

341

High Light-Extraction GaN-Based Vertical LEDs With Double Diffuse Surfaces  

Microsoft Academic Search

High light -extraction (external quantum efficiency ~40%) 465 -nm GaN -based vertical light -emitting diodes (LEDs) employing double diffuse surfaces were fabricated. The high scattering efficiency of double diffused surfaces could be responsible for the high light output power. ©2006 Optical Society of America OCIS codes: (230. 3670 )

Ya-Ju Lee; Hao-Chung Kuo; Tien-Chang Lu; Shing-Chung Wang

2006-01-01

342

Surface plasmon resonance biochip based on ZnO thin film for nitric oxide sensing  

Microsoft Academic Search

In this study, the design of a novel optical sensor that comprises surface plasmon resonance sensing chip and zinc oxide nano-film was proposed for the detection of nitric oxide gas. The electrical and optical properties of zinc oxide film vary in the presence of nitric oxide. This effect was utilized to prepare biochemical sensors with transduction based on surface plasmon

Wei-Yi Fenga; Nan-Fu Chiub; Hui-Hsin Lub; Hsueh-Ching Shihc; Dongfang Yangd; Chii-Wann Lina

2008-01-01

343

Predictions on surface finish in electrical discharge machining based upon neural network models  

Microsoft Academic Search

Predictions on the surface finish of work-pieces in electrical discharge machining (EDM) based upon physical or empirical models have been reported in the past years. However, when the change of electrode polarity has been considered, very few models have given reliable predictions. In this study, the comparisons on predictions of surface finish for various work materials with the change of

Kuo-Ming Tsai; Pei-Jen Wang

2001-01-01

344

Satellite-based observations of surface turbulent stress during severe weather  

E-print Network

Satellite-based observations of surface turbulent stress during severe weather Mark A. Bourassa The environment of severe marine weather is harsh: in situ and satellite observations of surface turbulent stresses are extremely difficult to acquire under such conditions. Even for fair weather conditions

345

Interference-based Investigation of Microscopic Objects Near Surfaces: a View From Below  

E-print Network

, microspheres can be conveniently analyzed to measure surface roughness based on fringe visibility. Also, precise and accurate measurements of microspheres’ size were performed by means of optimized and robust fringe spacing analysis. Finally, RICM’s distinctive...

Contreras Naranjo, Jose Clemente

2013-11-26

346

A surface-based model for cardiac electrophysiology and related inverse problems  

E-print Network

A surface-based model for cardiac electrophysiology and related inverse problems Annabelle Collin Inria Saclay ^Ile-de-France, France https://m3disim.saclay.inria.fr/m3disim-staff/annabelle-collin April

Segatti, Antonio

347

Acid-base site detection and mapping on solid surfaces by Kelvin force microscopy (KFM).  

PubMed

Electrostatic potential at the surface of acidic or basic solids changes under higher relative humidity (RH), as determined by using Kelvin force microscopy (KFM). The potential on acid surfaces becomes more negative as the water vapor pressure increases, while it becomes more positive on basic solids. These results verify the following hypothesis: OH(-) or H(+) ions associated with atmospheric water ion clusters are selectively adsorbed on solid surfaces, depending on the respective Brønsted acid or base character. Therefore, Kelvin microscopy, under variable humidity, is a rigorous but convenient alternative to determine the acid-base character of solid surfaces, with a great advantage: it uses only one amphoteric and simple reagent to determine both the acid and base sites. Moreover, this technique provides information on the spatial distribution of acid-base sites, which is currently inaccessible to any other method. PMID:23126418

Gouveia, Rubia F; Bernardes, Juliana S; Ducati, Telma R D; Galembeck, Fernando

2012-12-01

348

Developing a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface  

E-print Network

on the quality of air, land, and water resources. The computation-intensive models are supported by resourcesDeveloping a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface Hsin-I Chang1

Jiang, Wen

349

Cell-based Metabolomics for Monitoring Ecological Impacts of Environmental Surface Waters  

EPA Science Inventory

Numerous surface waters are adversely impacted by contaminants released from sources such as WWfPs, CAFOs, mining activities, and agricultural operations. Ideally, an assessment strategy for these applications would include both chemical identification and effects-based monitorin...

350

Interactive object modelling based on piecewise planar surface patches?  

PubMed Central

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

Prankl, Johann; Zillich, Michael; Vincze, Markus

2013-01-01

351

Bond of acrylic teeth to different denture base resins after various surface-conditioning methods.  

PubMed

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

Lang, Reinhold; Kolbeck, Carola; Bergmann, Rainer; Handel, Gerhard; Rosentritt, Martin

2012-02-01

352

Detection of methane by a surface plasmon resonance sensor based on polarization interferometry and angle modulation  

NASA Astrophysics Data System (ADS)

A novel methane sensor based on surface plasmon resonance is presented. An isoprene rubber (IPR) film is used as the sensing layer for methane. With the technologies of polarization interferometry and angle modulation, a detecting resolution of 700 ppm is achieved, which is better than previously reported methane sensors based on surface plasmon resonance and has a potential to be improved. The technique could have potential applications in monitoring methane concentrations.

Liu, Le; Hu, Zhaoxu; Ma, Suihua; Zhang, Ying; He, Yonghong; Guo, Jihua

2010-12-01

353

Establishing material properties for thin asphalt concrete surfaces on granular bases  

E-print Network

ESTABLISHING MATERIAL PROPERTIES FOR THIN ASPHALT CONCRETE SURFACES ON GRANULAR BASES A Thesis by BARRY THOMAS ROSSON Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1985 Major Subject: Civil Engineering ESTABLISHING MATERIAL PROPERTIES FOR THIN ASPHALT CONCRETE SURFACES ON GRANULAR BASES A Thesis by BARRY THOMAS ROSSON Approved as to style and content by: Fr y L. Roberts (Cha man...

Rosson, Barry Thomas

2012-06-07

354

Effect of Surface Roughness on the Oxidation Behavior of the Ni-Base Superalloy ME3  

Microsoft Academic Search

Ni-base superalloys are used in applications, such as jet aircraft engines and power production facilities that require excellent\\u000a elevated temperature oxidation resistance. This present work evaluated the effect of surface roughness on the oxidation behavior\\u000a of the Ni-base superalloy ME3. Isothermal oxidation tests were performed in air at different times to investigate the oxide\\u000a growth kinetics. The surface oxides were

Jeffrey L. Evans

2010-01-01

355

Effect of Surface Roughness on the Oxidation Behavior of the Ni-Base Superalloy ME3  

Microsoft Academic Search

Ni-base superalloys are used in applications, such as jet aircraft engines and power production facilities that require excellent elevated temperature oxidation resistance. This present work evaluated the effect of surface roughness on the oxidation behavior of the Ni-base superalloy ME3. Isothermal oxidation tests were performed in air at different times to investigate the oxide growth kinetics. The surface oxides were

Jeffrey L. Evans

2010-01-01

356

Nonfunctionalized Polydimethyl Siloxane Superhydrophobic Surfaces Based on Hydrophobic-Hydrophilic Interactions  

SciTech Connect

Superhydrophobic surfaces based on polydimethyl siloxane (PDMS) were fabricated using a 50:50 PDM-poly(ethylene glycol) (PEG) blend. PDMS was mixed with PEG, and incomplete phase separation yielded a hierarchic structure. The phase-separated mixture was annealed at a temperature close to the crystallization temperature of the PEG. The PEG crystals were formed isothermally at the PDMS/PEG interface, leading to an engineered surface with PDMS spherulites. The resulting roughness of the surface was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The PDMS spherulites, a few micrometers in diameter observed from SEM images, were found to have an undulated (rippled) surface with nanometer-sized features. The combination of micrometer- and nanometer-sized surface features created a fractal surface and increased the water contact angle (WCA) of PDMS more than 60, resulting in a superhydrophobic PDMS surface with WCA of >160 degrees. The active surface layer for the superhydrophobicity was approximately 100 mu m thick, illustrating that the material had bulk superhydrophobicity compared to conventional fluorocarbon or fluorinated coated rough surfaces. Theoretical analysis of the fractal surface indicates that the constructed surface has a fractal dimension of 2.5, which corresponds to the Apollonian sphere packing.

Polizos, Georgios [Oak Ridge National Laboratory (ORNL); Tuncer, Enis [ORNL; Qiu, Xiaofeng [ORNL; Aytug, Tolga [ORNL; Kidder, Michelle [ORNL; Messman, Jamie M [ORNL; Sauers, Isidor [ORNL

2011-01-01

357

Friction and surface chemistry of some ferrous-base metallic glasses  

NASA Technical Reports Server (NTRS)

The friction properties of some ferrous-base metallic glasses were measured both in argon and in vacuum to a temperature of 350 C. The alloy surfaces were also analyzed with X-ray photoelectron spectroscopy to identify the compounds and elements present on the surface. The results of the investigation indicate that even when the surfaces of the amorphous alloys, or metallic glasses, are atomically clean, bulk contaminants such as boric oxide and silicon dioxide diffuse to the surfaces. Friction measurements in both argon and vacuum indicate that the alloys exhibit higher coefficients of friction in the crystalline state than they do in the amorphous state.

Miyoshi, K.; Buckley, D. H.

1982-01-01

358

Pdf modeling for premixed turbulent combustion based on the properties of iso-concentration surfaces  

NASA Technical Reports Server (NTRS)

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.

Vervisch, L.; Kollmann, W.; Bray, K. N. C.; Mantel, T.

1994-01-01

359

Surface impedance based microwave imaging method for breast cancer screening: contrast-enhanced scenario  

NASA Astrophysics Data System (ADS)

A new microwave imaging method that uses microwave contrast agents is presented for the detection and localization of breast tumours. The method is based on the reconstruction of breast surface impedance through a measured scattered field. The surface impedance modelling allows for representing the electrical properties of the breasts in terms of impedance boundary conditions, which enable us to map the inner structure of the breasts into surface impedance functions. Later a simple quantitative method is proposed to screen breasts against malignant tumours where the detection procedure is based on weighted cross correlations among impedance functions. Numerical results demonstrate that the method is capable of detecting small malignancies and provides reasonable localization.

Güren, Onan; Çayören, Mehmet; Tükenmez Ergene, Lale; Akduman, Ibrahim

2014-10-01

360

Surface transport properties of Fe-based superconductors: The influence of degradation and inhomogeneity  

SciTech Connect

Surface properties of Co-doped BaFe{sub 2}As{sub 2} epitaxial superconducting thin films were inspected by X-ray photoelectron spectroscopy, scanning spreading resistance microscopy (SSRM), and point contact spectroscopy (PCS). It has been shown that surface of Fe-based superconductors degrades rapidly if being exposed to air, what results in suppression of gap-like structure on PCS spectra. Moreover, SSRM measurements revealed inhomogeneous surface conductivity, what is consistent with strong dependence of PCS spectra on contact position. Presented results suggest that fresh surface and small probing area should be assured for surface sensitive measurements like PCS to obtain intrinsic properties of Fe-based superconductors.

Plecenik, T.; Gregor, M.; Sobota, R.; Truchly, M.; Satrapinskyy, L.; Kus, P.; Plecenik, A. [Department of Experimental Physics, FMPI, Comenius University, 842 48 Bratislava (Slovakia)] [Department of Experimental Physics, FMPI, Comenius University, 842 48 Bratislava (Slovakia); Kurth, F.; Holzapfel, B.; Iida, K. [Institute for Metallic Materials, IFW Dresden, P. O. Box 270116, D-01171 Dresden (Germany)] [Institute for Metallic Materials, IFW Dresden, P. O. Box 270116, D-01171 Dresden (Germany)

2013-07-29

361

Laser restoring the glass surface treated with acid-based paint  

NASA Astrophysics Data System (ADS)

The modern city facilities are often being attacked by graffiti artists, and increasingly vandals leave "tags" using paints, which compound based on acids, hydrofluoric or acetic commonly. These paints not only ink the surface, but also increase the surface roughness, and such impact can not be corrected by conventional cleaning. Thus, it was requested to develop technology that would not only clean the surface, but also to restore its structure by smoothing out irregularities and roughness formed after exposure in acid. In this work we investigated the effect of restoring the surface of the glass, spoiled by acid-based paint and then treated with CO2-laser. During the experiments, it was found that it is real to create the single-step laser surface restoring technology.

Strusevich, Anastasia V.; Poltaev, Yuriy A.; Sinev, Dmitrii A.

2013-11-01

362

Graphene-based textured surface by pulsed laser deposition as a robust platform for surface enhanced Raman scattering applications  

NASA Astrophysics Data System (ADS)

We have developed a surface enhanced Raman scattering (SERS)-active substrate based on gold nanoparticles-decorated few-layer (fl) graphene grown by pulsed laser deposition. Diamond-Like Carbon film has been converted to fl-graphene after thermal annealing at low temperature. The formation of fl-graphene was confirmed by Raman spectroscopy, and surface morphology was highlighted by scanning electron microscopy. We found that textured fl-graphene film with nanoscale roughness was highly beneficial for SERS detection. Rhodamine 6G and p-aminothiophenol proposed as test molecules were detected with high sensitivity. The detection at low concentration of deltamethrin, an active molecule of a commercial pesticide was further demonstrated.

Tite, T.; Donnet, C.; Loir, A.-S.; Reynaud, S.; Michalon, J.-Y.; Vocanson, F.; Garrelie, F.

2014-01-01

363

Automatic Magnetic Particle Inspection System for the Bracket Welds of Atucha i Nuclear Power Plant Pressure Vessel  

NASA Astrophysics Data System (ADS)

The present work refers to the welding inspection of the brackets of Atucha I Nuclear Power Plant's Pressure Vessel (RPV) using the wet fluorescent magnetic particles technique (MT). Due to limited access and high radiation levels in the inspection area, it was necessary to automate the testing and use non conventional magnetization techniques. This paper describes the design and implementation of an automated inspection device and the tests carried out on the mock-up to set up the system. Also, magnetization techniques used are described, explaining in detail the non conventional technique of magnetization by current plates and the use of magnetic field concentrators to increase the field values in the area of interest. Finally, the device mounted on the RPV, used to inspect the bracket's weld, and the results achieved from the inspection are shown.

Katchadjian, P.; Desimone, C.; Garcia, A.; Antonaccio, C.; Schroeter, F.; Mastroleonardo, P.

2011-06-01

364

Mechanically tunable surface plasmon resonance based on gold nanoparticles and elastic membrane polydimethylsiloxane composite  

NASA Astrophysics Data System (ADS)

Surface plasmon in nanoscaled materials has recently attracted a great deal of attention due to its possibility in a wide range of application. From a practical standpoint, it is desirable for the devices having a tunability of surface plasmon frequency. To achieve this goal, in this study, a composite consisting of two-dimensional gold nanoparticles array embedded in elastic polydimethylsiloxane (PDMS) membrane has been synthesized. Because the elastic PDMS membrane has a high malleability, with an external stress, it is very easy to regulate the interparticle distance in the gold nanoparticle array. The change in the distance between each nanoparticle will alter the surface plasmon interaction, and hence surface plasmon frequency can be manipulated. It is found that when the interparticle distance increases, the enhanced surface plasma mutual coupling will cause the blueshift of surface plasmon resonance frequency. The observed result satisfies the forecast based on electromagnetic theory.

Chiang, Yu-Lun; Chen, Chih-Wei; Wang, Chun-Hsiung; Hsieh, Chun-Yi; Chen, Yung-Ting; Shih, Han-Yu; Chen, Yang-Fang

2010-01-01

365

Peculiar surface behavior of some ionic liquids based on active pharmaceutical ingredients  

NASA Astrophysics Data System (ADS)

The ionic liquids based on biologically active cations and anions, commonly designated by ionic liquids based on active pharmaceutical ingredients (ILs-APIs), are interesting compounds for use in pharmaceutical applications. Lidocaine docusate, ranitidine docusate, and didecyldimethylammonium ibuprofen are examples of promising ILs-APIs that were recently synthesized. They were submitted to biological testing and calorimetric measurements, but nothing is known about their surface properties. In this work, we measured the surface tension and the contact angles on both hydrophilic and hydrophobic surfaces in a temperature range as wide as possible. Based on the wettability data, the polarity fractions were estimated using the Fowkes theory. The peculiar surface behavior observed was tentatively attributed to the presence of mesophases.

Restolho, José; Mata, José Luis; Saramago, Benilde

2011-02-01

366

Er:YAG Laser for Brackets Bonding: A SEM Study after Debonding  

PubMed Central

Background. The introduction of Er:YAG laser in dentistry for ablation of hard tissues advocated an alternative method of enamel etching for orthodontics purpose. Materials and Methods. 55 extracted human third molars were inserted in acrylic resin blocks and divided into five groups of 11 teeth. Group 1 was treated with 37% orthophosphoric acid for 30 seconds. Group 2 was treated with laser irradiation (Er:YAG Fidelius III, Fotona, Slovenia) at 80?mJ and 4?Hz. Group 3 underwent laser treatment (80?mJ, 4?Hz), followed by 37% orthophosphoric acid for 30 seconds. The teeth in Group 4 were treated with laser at 40?mJ and 10?Hz. The teeth in Group 5 were treated with laser (40?mJ, 10?Hz), followed by 37% orthophosphoric acid for 30 seconds. The adhesive remnant index was determined after debonding. Results. Kruskas-Wallis test showed that location parameters (median and mean) are significantly different between Groups 2 and 4 when compared with control group; on the contrary no significant difference was detected between Groups 3 and 5 with the controls. Conclusion. The use of Er:YAG laser alone, as in Groups 2 and 4, showed no significant advantages over phosphoric acid in the bonding procedure for orthodontics brackets.

Ierardo, G.; Di Carlo, G.; Petrillo, F.; Luzzi, V.; Vozza, I.; Migliau, G.; Kornblit, R.; Rocca, J. P.; Polimeni, A.

2014-01-01

367

Long-term Failure Rate of Brackets Bonded with Plasma and High-intensity Light-emitting Diode Curing Lights: A Clinical Assessment  

Microsoft Academic Search

Objective: To comparatively assess the long-term failure rate of brackets bonded with a plasma or a high-intensity light-emitting diode (LED) curing light. Materials and Methods: Twenty-five patients with complete permanent dentitions with similar treatment planning and mechanotherapy were selected for the study. Brackets were bonded ac- cording to a split-mouth design with the 3M Ortholite Plasma or the high-power Satelec

Nikolaos Pandis; Sophia Strigoub; Theodore Eliades

2007-01-01

368

Use of palatal miniscrew anchorage and lingual multi-bracket appliances to enhance efficiency of molar scissors-bite correction.  

PubMed

This article reports the successful treatment method of scissors-bite correction using miniscrew anchorage and a lingual multi-bracket appliance. A female patient, 17 years and 4 months old, had a chief complaint of crowding of anterior teeth. The patient was given the diagnosis of Angle Class I malocclusion with bimaxillary protrusion and incisor crowding. She also showed a scissors-bite of the second molar on the right side. Miniscrews were inserted into the palatal region of the upper second molar to reinforce the anchorage, and a lingual multi-bracket appliance was placed into the maxilla. Miniscrews inserted palatally were used to correct the scissors-bite in the first 3 months; afterward, they were used to retract the six anterior teeth. The total active treatment period was 26 months. Because of the bite-plane effect, the upper and lower molars were separated in occlusion, and the scissors-bite was corrected effectively within a short time. The combined use of palatal miniscrew anchorage and lingual multi-bracket appliances enhances efficiency of molar scissors-bite correction. PMID:19413381

Tamamura, Nagato; Kuroda, Shingo; Sugawara, Yasuyo; Takano-Yamamoto, Teruko; Yamashiro, Takashi

2009-05-01

369

The coupling of cloud base height and surface fluxes: a transferability intercomparison  

NASA Astrophysics Data System (ADS)

This paper presents an evaluation of the simulated coupling between cloud base height (CBH) and surface fluxes over selected Coordinated Enhanced Observing Period (CEOP) reference stations by five regional climate models as part of a transferability intercomparison experiment. The model results are compared with station data obtained during the first phase of the CEOP measuring campaigns. The models gave a credible simulation of both diurnal and seasonal cycles of cloud base height and surface variables over the stations. However, the models exhibited some difficulty in reproducing the diurnal and seasonal temperatures over the tropical stations. The study used principal component analysis to show that three factors account for most of the variability in the observed and simulated data and to investigate the coupling between cloud base height and surface fluxes in the data. In the observations, CBH is well coupled with the surface fluxes over Cabauw, Bondville, Lamont, and Berms, but coupled only with temperature over Lindenberg and Tongyu. All models but GEMLAM simulate substantial coupling between CBH and surface fluxes at all stations; GEMLAM does not couple CBH with surface fluxes, but with surface temperature and specific humidity.

Gbobaniyi, Emiola O.; Abiodun, Babatunde J.; Tadross, Mark A.; Hewitson, Bruce C.; Gutowski, William J.

2011-11-01

370

Naval surface-based infrared search and track (IRST) target signature climatology analysis  

Microsoft Academic Search

A methodology is presented for estimating the impact of meteorological conditions on the detection of airborne targets by a naval surface-based IRST system. This is accomplished by linking a target signature computer code to a weather data base and collecting target contrast signature statistics as a function of target range. System performance is determined by comparing the IRST detection requirements

P. P. Ostrowski; R. W. Snedegar

1990-01-01

371

Sub-word unit based non-audible speech recognition using surface electromyography  

Microsoft Academic Search

In this paper we present a novel approach for a surface elec- tromyographic speech recognition system based on sub-word units. Rather than using full word models as integrated in our previous work we propose here smaller sub-word units as prereq- uisites for large vocabulary speech recognition. This allows the recognition of words not seen in the training set based on

Matthias Walliczek; Florian Kraft; Szu-Chen Stan Jou; Tanja Schultz; Alex Waibel

2006-01-01

372

THREE-DIMENSIONAL SOUND FIELD REPRODUCTION AND RECORDING SYSTEMS BASED ON BOUNDARY SURFACE CONTROL PRINCIPLE  

Microsoft Academic Search

Based on the boundary surface control (BSC) principle, a new recording\\/reproduction system is developed to realize high fidelity three-dimensional sound field reproduction. Theoretically, using this new system, perfect sound field reproduction can be achieved in any acoustic environment. Sound recording \\/ reproduction sys- tems based on the BSC principle require many loudspeakers and microphones. In the new system, the microphone

Seigo Enomoto; Yusuke Ikeda; Shiro Ise; Satoshi Nakamura

2008-01-01

373

Nanocluster-based white-light-emitting material employing surface tuning  

DOEpatents

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.

Wilcoxon, Jess P. (Albuquerque, NM); Abrams, Billie L. (Albuquerque, NM); Thoma, Steven G. (Albuquerque, NM)

2007-06-26

374

Broadly tunable one-way terahertz plasmonic waveguide based on nonreciprocal surface magneto plasmons.  

PubMed

One-way-propagating broadly tunable terahertz plasmonic waveguide at a subwavelength scale is proposed based on a metal-dielectric-semiconductor structure. Unlike other one-way plasmonic devices that are based on interference effects of surface plasmons, the proposed one-way device is based on nonreciprocal surface magneto plasmons under an external magnetic field. Theoretical and simulation results demonstrate that the one-way-propagating frequency band can be broadly tuned by the external magnetic fields. The proposed concept can be used to realize various high performance tunable plasmonic devices such as isolators, switches and splitters for ultracompact integrated plasmonic circuits. PMID:22660065

Hu, Bin; Wang, Qi Jie; Zhang, Ying

2012-06-01

375

Surface enhanced Raman spectroscopy (SERS) for the discrimination of Arthrobacter strains based on variations in cell surface composition.  

PubMed

Surface enhanced Raman spectroscopy (SERS) is a rapid and highly sensitive spectroscopic technique that has the potential to measure chemical changes in bacterial cell surface in response to environmental changes. The objective of this study was to determine whether SERS had sufficient resolution to differentiate closely related bacteria within a genus grown on solid and liquid medium, and a single Arthrobacter strain grown in multiple chromate concentrations. Fourteen closely related Arthrobacter strains, based on their 16S rRNA gene sequences, were used in this study. After performing principal component analysis in conjunction with Linear Discriminant Analysis, we used a novel, adapted cross-validation method, which more faithfully models the classification of spectra. All fourteen strains could be classified with up to 97% accuracy. The hierarchical trees comparing SERS spectra from the liquid and solid media datasets were different. Additionally, hierarchical trees created from the Raman data were different from those obtained using 16S rRNA gene sequences (a phylogenetic measure). A single bacterial strain grown on solid media culture with three different chromate levels also showed significant spectral distinction at discrete points identified by the new Elastic Net regularized regression method demonstrating the ability of SERS to detect environmentally induced changes in cell surface composition. This study demonstrates that SERS is effective in distinguishing between a large number of very closely related Arthrobacter strains and could be a valuable tool for rapid monitoring and characterization of phenotypic variations in a single population in response to environmental conditions. PMID:22842541

Stephen, Kate E; Homrighausen, Darren; DePalma, Glen; Nakatsu, Cindy H; Irudayaraj, Joseph

2012-09-21

376

Low dimensional self-organization of DNA-base molecules on Cu(111) surfaces  

NASA Astrophysics Data System (ADS)

DNA base molecules form novel low dimensional superstructures on Cu(111) surfaces through hydrogen bonding among molecules and through their epitaxial nature on the surface. Scanning tunneling microscope images have revealed that the chemical inertness of the Cu(111) substrate allows the molecules to diffuse over the surface to spontaneously self-assemble themselves into their own unique structure: adenine into one-dimensional molecular chains, thymine into two-dimensional islands, guanine into two-dimensional square lattices and cytosine into one-dimensional zigzag molecule-cluster networks. Molecular orbital calculations explain some of the observed self-assemblies induced by base-base hydrogen bonding. Novel superstructures of self-assembled uracial molecules have also been observed at 70 K. Isolated uracil trimers are formed at low coverage, and two-dimensional islands with a hexagonal superstructure are built up at increased coverage. The dominant force responsible for the formation of the trimers and the islands is electrostatic interaction through anisotropic hydrogen bonds between uracil molecules. This paper also discusses the DNA base molecules/surface interactions to form different adsorbed structures on various surfaces, such as SrTiO 3(100), Pd(110) and Si(100)-(2 × 1), correlated with the chemical bonding and corrugation of the surface.

Kawai, Tomoji; Tanaka, Hiroyuki; Nakagawa, Takaomi

1997-10-01

377

Fast time-of-flight camera based surface registration for radiotherapy patient positioning  

SciTech Connect

Purpose: This work introduces a rigid registration framework for patient positioning in radiotherapy, based on real-time surface acquisition by a time-of-flight (ToF) camera. Dynamic properties of the system are also investigated for future gating/tracking strategies. Methods: A novel preregistration algorithm, based on translation and rotation-invariant features representing surface structures, was developed. Using these features, corresponding three-dimensional points were computed in order to determine initial registration parameters. These parameters became a robust input to an accelerated version of the iterative closest point (ICP) algorithm for the fine-tuning of the registration result. Distance calibration and Kalman filtering were used to compensate for ToF-camera dependent noise. Additionally, the advantage of using the feature based preregistration over an ''ICP only'' strategy was evaluated, as well as the robustness of the rigid-transformation-based method to deformation. Results: The proposed surface registration method was validated using phantom data. A mean target registration error (TRE) for translations and rotations of 1.62 {+-} 1.08 mm and 0.07 deg. {+-} 0.05 deg., respectively, was achieved. There was a temporal delay of about 65 ms in the registration output, which can be seen as negligible considering the dynamics of biological systems. Feature based preregistration allowed for accurate and robust registrations even at very large initial displacements. Deformations affected the accuracy of the results, necessitating particular care in cases of deformed surfaces. Conclusions: The proposed solution is able to solve surface registration problems with an accuracy suitable for radiotherapy cases where external surfaces offer primary or complementary information to patient positioning. The system shows promising dynamic properties for its use in gating/tracking applications. The overall system is competitive with commonly-used surface registration technologies. Its main benefit is the usage of a cost-effective off-the-shelf technology for surface acquisition. Further strategies to improve the registration accuracy are under development.

Placht, Simon; Stancanello, Joseph; Schaller, Christian; Balda, Michael; Angelopoulou, Elli [Metrilus GmbH, Henkestr. 91, 91052 Erlangen (Germany) and Pattern Recognition Lab, Friedrich Alexander University Erlangen-Nuremberg, Martensstr. 3, 91058 Erlangen (Germany); German Research Cancer Centre, Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Metrilus GmbH, Henkestr. 91, 91052 Erlangen (Germany); Pattern Recognition Lab, Friedrich Alexander University Erlangen-Nuremberg, Martensstr. 3, 91058 Erlangen (Germany)

2012-01-15

378

Functional specializations in human cerebral cortex analyzed using the Visible Man surface-based atlas  

NASA Technical Reports Server (NTRS)

We used surface-based representations to analyze functional specializations in the human cerebral cortex. A computerized reconstruction of the cortical surface of the Visible Man digital atlas was generated and transformed to the Talairach coordinate system. This surface was also flattened and used to establish a surface-based coordinate system that respects the topology of the cortical sheet. The linkage between two-dimensional and three-dimensional representations allows the locations of published neuroimaging activation foci to be stereotaxically projected onto the Visible Man cortical flat map. An analysis of two activation studies related to the hearing and reading of music and of words illustrates how this approach permits the systematic estimation of the degree of functional segregation and of potential functional overlap for different aspects of sensory processing.

Drury, H. A.; Van Essen, D. C.

1997-01-01

379

Space-Based Diagnosis of Surface Ozone Sensitivity to Anthropogenic Emissions  

NASA Technical Reports Server (NTRS)

We present a novel capability in satellite remote sensing with implications for air pollution control strategy. We show that the ratio of formaldehyde columns to tropospheric nitrogen dioxide columns is an indicator of the relative sensitivity of surface ozone to emissions of nitrogen oxides (NO(x) = NO + NO2) and volatile organic compounds (VOCs). The diagnosis from these space-based observations is highly consistent with current understanding of surface ozone chemistry based on in situ observations. The satellite-derived ratios indicate that surface ozone is more sensitive to emissions of NO(x) than of VOCs throughout most continental regions of the Northern Hemisphere during summer. Exceptions include Los Angeles and industrial areas of Germany. A seasonal transition occurs in the fall when surface ozone becomes less sensitive to NOx and more sensitive to VOCs.

Martin, Randall V.; Fiore, Arlene M.; VanDonkelaar, Aaron

2004-01-01

380

Final report of ''Fundamental Surface Reaction Mechanisms in Fluorocarbon Plasma-Based Processing''  

SciTech Connect

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.

Gottlieb S. Oehrlein; H. Anderson; J. Cecchi; D. Graves

2004-09-21

381

Mechanical and electrical cold bonding based on metallic nanowire surface fasteners.  

PubMed

Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we propose a new patterned structure of Au nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N cm(-2). Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2 ?. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs. PMID:22909983

Ju, Yang; Amano, Masahiro; Chen, Mingji

2012-09-14

382

Electron-induced surface reactivity modification in Zinc oxide-based thin films  

SciTech Connect

Chemical surface reactivity is a key parameter in modern microelectronic and display technology that is defined by basic physical interactions at the liquid etcher/material surface interface. We apply recently developed low-energy electron irradiation method for surface modification of zinc oxide-based thin films affording to vary physical processes at the liquid agent/material surface interface/and widely tune its chemical reactivity. Electron irradiation leads to the formation of ultrathin layer on irradiated surface, without generation of volumetric defects, and preserves original optical and conductive properties. The method allows fabrication of high-resolution patterned templates with modified chemical etching resistance for the fabrication of three-dimensional patterned arrays.

Sabayev, V.; Aronov, D.; Rosenman, G. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Oster, L. [Sami Shamoon Academic College of Engineering, Beer-Sheva 84100 (Israel)

2008-10-06

383

Mapping surface energy balance components by combining Landsat Thematic Mapper and ground-based meteorological data  

NASA Technical Reports Server (NTRS)

Surface energy balance components were evaluated by combining satellite-based spectral data with on-site measurements of solar irradiance, air temperature, wind speed, and vapor pressure. Maps of latent heat flux density and net radiant flux density were produced using Landsat TM data for three dates. The TM-based estimates differed from Bowen-ratio and aircraft-based estimates by less than 12 percent over mature fields of cotton, wheat, and alfalfa.

Moran, M. Susan; Jackson, Ray D.; Raymond, Lee H.; Gay, Lloyd W.; Slater, Philip N.

1989-01-01

384

Dielectrophoresis-Based Discrimination of Bacteria at the Strain Level Based on Their Surface Properties  

E-print Network

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 ...

Willner, Dana

385

Microdetermination of silicon dioxide on the surface by sensors based on perfluorinated proton-conducting membranes  

NASA Astrophysics Data System (ADS)

A microdetermination method of silicon dioxide on the silicon surface is studied. In this method, a thin SiO2 layer is dissolved in an aqueous solution of hydrofluoric acid and then the resulting solution is analyzed with sensors based on perfluorinated proton-conducting membranes. Quantitative determination of silicon dioxide remaining on the silicon surface in a quantity as low as 1 × 10-6 mol is demonstrated to be feasible.

Nikitin, S. E.; Terukov, E. I.; Timofeev, S. V.; Manabaev, N. K.

2012-06-01

386

Surface modifications based on the cyanobacterial siderophore anachelin: from structure to functional biomaterials design  

Microsoft Academic Search

This review describes the design, synthesis and evaluation of novel catechol based anchors for surface modification. The anachelin\\u000a chromophore, the catecholate fragment of the siderophore anachelin from the cyanobacterium Anabaena cylindrica, allows for the immobilization of polyethylene glycol (PEG) on titania and glass surfaces thus rendering them protein resistant\\u000a and antifouling. It is proposed that catecholate siderophores constitute a class

Karl Gademann; Joanna Kobylinska; Jean-Yves Wach; Tom M. Woods

2009-01-01

387

Automatic Path Planning for Welding Robot Based on Reconstructed Surface Model  

Microsoft Academic Search

An automatic path planning method, including the torch pose planning, is proposed to improve the flexibility and automatic\\u000a planning ability of arc welding robot. The virtual object, which representing the real object to be welded, is reconstructed\\u000a firstly by non-rational B-spline surface from geometric polygonal mesh model or measured point cloud. Based on the reconstructed\\u000a non-rational surface model, the tangent

Wusheng Chou; Liang You; Tianmiao Wang

388

Surface properties of poly(dimethylsiloxane)-based inorganic\\/organic hybrid materials  

Microsoft Academic Search

Poly(dimethylsiloxane) (PDMS)-based hybrid materials were prepared by the sol–gel method on Si wafers, Al and polystyrene (PS) substrates. The reaction was monitored by attenuated total reflectance-infrared (ATR-IR) spectroscopy. The hybrid materials have always one surface made in contact with air and one with a substrate. These surfaces were investigated by using tapping mode atomic force microscopy (AFM), X-ray photo-electron spectroscopy

Zhili Li; Wei Han; Dimitry Kozodaev; José C. M. Brokken-Zijp; Peter C. Thüne

2006-01-01

389

Facile method for preparing surface-mounted cucurbit[8]uril-based rotaxanes.  

PubMed

Surface-immobilized rotaxanes are of practical interest for myriad applications including molecular rotors and analytical sensing. Herein, we present a facile method for the preparation of cucurbit[8]uril (CB[8])-based rotaxanes on gold (Au) surfaces threaded onto a viologen (MV(2+)) axle. The surface-bound CB[8] rotaxanes were characterized by contact angle measurements and optical microscopy. Direct imaging of the rotaxanes was accomplished by attaching either azobenzene-functionalized silica (Si-azo) colloids or fluorescein-labeled dopamine that were bound to the Au surface through a supramolecular heteroternary (1:1:1) complex with CB[8]. The surface density of CB[8] rotaxanes was examined based on their detection of dopamine. The calculated surface density is 4.8 × 10(13) molecules·cm(-2), which is only slightly lower than the theoretical value of 5.0 × 10(13) molecules·cm(-2). Surface-functionalized rotaxanes can be reversibly switched using external stimuli to bind electron-rich second guests for CB[8], including both small molecules such as dopamine and appropriately-functionalized colloidal particles. Such controlled reversibility gives rise to potential applications including selective sensing or reusable templates for preparing well-defined colloidal arrays. The formation of the surface-bound rotaxane structure is critical for successfully anchoring CB[8] host molecules onto Au substrates, yielding an interlocked architecture and preventing the dissociation of binary host-guest complex MV(2+)?CB[8]. The MV(2+)?CB[8] rotaxane structure thus effectively maintains the material density on the Au surface and dramatically enhances the stability of the functional surface. PMID:25170789

Hu, Chi; Lan, Yang; Tian, Feng; West, Kevin R; Scherman, Oren A

2014-09-16

390

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

NASA Astrophysics Data System (ADS)

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.

Shankaran, Dhesingh Ravi; Miura, Norio

2007-12-01

391

UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersion.  

PubMed

UV-curable low surface energy fluorinated polycarbonate-based polyurethane dispersions were synthesized by incorporating a hydroxy-terminated perfluoropolyether (PFPE) into the soft segment of polyurethane. The effects of the PFPE content on the UV-curing behavior, physical, surface, thermal properties and refractive index were investigated. The UV-curing behavior was analyzed by photo-differential scanning calorimetry. The surface free energy of the UV-cured film, which is related to the water or oil repellency, was calculated from contact angle measurements using the Lewis acid-base three liquids method. The surface free energy decreased significantly with increasing fluorine concentration because PFPE in the soft segment was tailored to the surface and produced a UV-cured film with a hydrophobic fluorine enriched surface, as confirmed by X-ray photoelectron spectroscopy. With increasing the fluorine content, the refractive indices of UV-cured films decreased. However, the UV-curing rate and final conversion was decreased with increasing contents of PFPE, which resulted in the decrease of the glass transition temperature (T(g)), crosslink density, tensile strength and surface hardness. PMID:21788027

Hwang, Hyeon-Deuk; Kim, Hyun-Joong

2011-10-15

392

Noninvasive probing of the ocean surface using laser-based nonlinear optical methods  

SciTech Connect

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.

Korenowski, G.M.; Frysinger, G.S.; Asher, W.E. (Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry)

1992-06-01

393

A comparative study of surface acid-base characteristics of natural illites from different origins  

SciTech Connect

The acid-base characteristics of naturally occurring illites, collected from different locations, were investigated by potentiometeric titrations. The experimental data were interpreted using the constant capacitance surface complexation model. Considerable release of Al and Si from illite samples and subsequent complexation or precipitation of hydroxyl aluminosilicates generated during the acidimetric forward titration and the alkalimetric back titration, respectively, were observed. In order to describe the acid-base chemistry of aqueous illite surfaces, two surface proton-reaction models, introducing the corresponding reactions between the dissolved aluminum species and silicic acid, as well as a surface Al-Si complex on homogeneous illite surface sites, were proposed. Optimization results indicated that both models could provide a good description of the titration behavior for all aqueous illite systems in this study. The intrinsic acidity constants for the different illites were similar in Model 1, showing some generalities in their acid-base properties. Model 1 may be considered as a simplification of Model 2, evident in the similarities between the corresponding constants. In addition, the formation constant for surface Al-Si species (complexes or precipitates) is relatively stable in this study.

Liu, W.; Sun, Z.; Forsling, W.; Du, Q.; Tang, H.

1999-11-01

394

Equilibrium surface tension, dynamic surface tension, and micellization properties of lactobionamide-type sugar-based gemini surfactants.  

PubMed

A sugar-based gemini surfactant N,N'-dialkyl-N,N'-dilactobionamideethylenediamine (2C(n)Lac, where n represents alkyl chain lengths of 8, 10, 12, and 14) was synthesized by reacting N,N'-dialkylethylenediamine with lactobionic acid. The adsorption properties of 2C(n)Lac were characterized by equilibrium and dynamic surface tension measurements. Their micellization properties were investigated by steady-state fluorescence using pyrene as a probe and dynamic light scattering (DLS) techniques. The dependence of these properties on the alkyl chain length and the number of sugars was determined through a comparison with the corresponding monomeric surfactants C(n)MLA and previously reported sugar-based gemini surfactants containing monosaccharide gluconamide or disaccharide lactobionamide groups with a hexanediamide spacer. The critical micelle concentration (cmc) and surface tension of 2C(n)Lac are both lower than those of C(n)MLA surfactants. These lower values indicate that the synthesized sugar-based gemini surfactants have excellent micelle-forming ability in solution and high adsorption ability at the air-water interface, which result from strong interactions of the hydrogen bonds between the hydroxyls in lactobionamide groups. When the alkyl chain length of 2C(n)Lac increases to 14, premicellar formation occurs in the solution along with adsorption at the air-water interface at concentrations below the cmc. Furthermore, 2C(n)Lac forms micelles measuring 4 to 12 nm in solution, with no dependence on the alkyl chain length, and their size slightly increases with increasing concentration. PMID:23728326

Yoshimura, Tomokazu; Umezawa, Shin; Fujino, Akihiko; Torigoe, Kanjiro; Sakai, Kenichi; Sakai, Hideki; Abe, Masahiko; Esumi, Kunio

2013-01-01

395

Surface modification of polyacrylonitrile-based carbon fiber and its interaction with imide  

NASA Astrophysics Data System (ADS)

In this work, sized polyacrylonitrile (PAN)-based carbon fibers were chemically modified with nitric acid and maleic anhydride (MA) in order to improve the interaction between carbon fiber surface and polyimide matrix. Bismaleimide (BMI) was selected as a model compound of polyimide to react with modified carbon fiber. The surface characteristic changing after modification and surface reaction was investigated by element analysis (EA), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and surface enhanced Raman scattering (SERS). The results indicated that the modification of carbon fiber surface with MA might follow the Diels Alder reaction mechanism. In the surface reaction between modified fibers and BMI, among the various surface functional groups, the hydroxyl group provided from phenolic hydroxyl group and bridged structure on carbon fiber may be the most effective group reacted with imide structure. The results may shed some light on the design of the appropriate surface structure, which could react with polyimide, and the manufacture of the carbon fiber-reinforced polyimide matrix composites.

Xu, Bing; Wang, Xiaoshu; Lu, Yun

2006-12-01

396

An implicit evolution scheme for active contours and surfaces based on IIR filtering.  

PubMed

In this work, we present an approach for implementing an implicit scheme for the numerical solution of the partial differential equation of the evolution of an active contour/surface. The proposed scheme is applicable to any variant of the traditional active contour (AC), irrespectively of the calculation of the image-based force field and it is readily applicable to explicitly parameterized active surfaces (AS). The proposed approach is formulated as an infinite impulse response (IIR) filtering of the coordinates of the contour/surface points. The poles of the filter are determined by the parameters controlling the shape of the active contour/surface. We show that the proposed IIR-based implicit evolution scheme has very low complexity. Furthermore, the proposed scheme is numerically stable, thus it allows the convergence of the AC/AS with significantly fewer iterations than the explicit evolution scheme. It also possesses the separability property along the two parameters of the AS, thus it may be applied to deformable surfaces, without the need to store and invert large sparse matrices. We implemented the proposed IIR-based implicit evolution scheme in the Vector Field Convolution (VFC) AC/AS using synthetic and clinical volumetric data. We compared the segmentation results with those of the explicit AC/AS evolution, in terms of accuracy and efficiency. Results show that the VFC AC/AS with the proposed IIR-based implicit evolution scheme achieves the same segmentation results with the explicit scheme, with considerably less computation time. PMID:24637146

Delibasis, Konstantinos K; Asvestas, Pantelis A; Kechriniotis, Aristides I; Matsopoulos, George K

2014-05-01

397

Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interface  

SciTech Connect

The plasma-material interface and its impact on the performance of magnetically confined thermonuclear fusion plasmas are considered to be one of the key scientific gaps in the realization of nuclear fusion power. At this interface, high particle and heat flux from the fusion plasma can limit the material's lifetime and reliability and therefore hinder operation of the fusion device. Lithium-based surfaces are now being used in major magnetic confinement fusion devices and have observed profound effects on plasma performance including enhanced confinement, suppression and control of edge localized modes (ELM), lower hydrogen recycling and impurity suppression. The critical spatial scale length of deuterium and helium particle interactions in lithium ranges between 5-100 nm depending on the incident particle energies at the edge and magnetic configuration. Lithium-based surfaces also range from liquid state to solid lithium coatings on a variety of substrates (e.g., graphite, stainless steel, refractory metal W/Mo/etc., or porous metal structures). Temperature-dependent effects from lithium-based surfaces as plasma facing components (PFC) include magnetohydrodynamic (MHD) instability issues related to liquid lithium, surface impurity, and deuterium retention issues, and anomalous physical sputtering increase at temperatures above lithium's melting point. The paper discusses the viability of lithium-based surfaces in future burning-plasma environments such as those found in ITER and DEMO-like fusion reactor devices.

Allain, Jean Paul; Taylor, Chase N. [School of Nuclear Engineering, Purdue University, 400 Central Avenue, West Lafayette, Indiana 47907 (United States)

2012-05-15

398

Lithium-based surfaces controlling fusion plasma behavior at the plasma-material interfacea)  

NASA Astrophysics Data System (ADS)

The plasma-material interface and its impact on the performance of magnetically confined thermonuclear fusion plasmas are considered to be one of the key scientific gaps in the realization of nuclear fusion power. At this interface, high particle and heat flux from the fusion plasma can limit the material's lifetime and reliability and therefore hinder operation of the fusion device. Lithium-based surfaces are now being used in major magnetic confinement fusion devices and have observed profound effects on plasma performance including enhanced confinement, suppression and control of edge localized modes (ELM), lower hydrogen recycling and impurity suppression. The critical spatial scale length of deuterium and helium particle interactions in lithium ranges between 5-100 nm depending on the incident particle energies at the edge and magnetic configuration. Lithium-based surfaces also range from liquid state to solid lithium coatings on a variety of substrates (e.g., graphite, stainless steel, refractory metal W/Mo/etc., or porous metal structures). Temperature-dependent effects from lithium-based surfaces as plasma facing components (PFC) include magnetohydrodynamic (MHD) instability issues related to liquid lithium, surface impurity, and deuterium retention issues, and anomalous physical sputtering increase at temperatures above lithium's melting point. The paper discusses the viability of lithium-based surfaces in future burning-plasma environments such as those found in ITER and DEMO-like fusion reactor devices.

Allain, Jean Paul; Taylor, Chase N.

2012-05-01

399

Assessment of genotoxicity of herbal medicinal products: application of the "bracketing and matrixing" concept using the example of Valerianae radix (valerian root).  

PubMed

An assessment of genotoxicity is a precondition for marketing authorization respectively registration of herbal medicinal products (HMPs), as well as for inclusion into the 'Community list of herbal substances, preparations and combinations thereof for use in traditional herbal medicinal products' established by the European Commission in accordance with Directive 2001/83/EC as amended, and based on proposals from the Committee on Herbal Medicinal Products (HMPC). In the 'Guideline on the assessment of genotoxicity of herbal substances/preparations' (EMEA/HMPC/107079/2007) HMPC has described a stepwise approach for genotoxicity testing, according to which the Ames test is a sufficient base for the assessment of genotoxicity in case of an unequivocally negative result. For reducing efforts for testing of individual herbal substances/preparations, HMPC has also developed the 'guideline on selection of test materials for genotoxicity testing for traditional herbal medicinal products/herbal medicinal products' (EMEA/HMPC/67644/2009) with the aim to allow testing of a standard range of test materials which could be considered representative of the commonly used preparations from a specific herbal drug according to a 'bracketing/matrixing' approach. The purpose of this paper is to provide data on the practical application of this bracketing and matrixing concept using the example of Valerianae radix, with the intention of facilitating its inclusion in the "Community list". Five extraction solvents, representing the extremes of the polarity range and including also mid-range extraction solvents, were used, covering the entire spectrum of phytochemical constituents of Valerianae radix, thereby including polar and non-polar constituents. Extracts were tested in the Ames test according to all relevant guidelines. Results were unequivocally negative for all extracts. A review of the literature showed that this result is in accordance with the available data, thus demonstrating the lack of a genotoxic potential. In conclusion the two guidelines on genotoxicity provide a practically applicable concept. Valerianae radix has no genotoxic potential, supporting its use in HMPs and its inclusion in the Community list. PMID:24837473

Kelber, Olaf; Wegener, Tankred; Steinhoff, Barbara; Staiger, Christiane; Wiesner, Jacqueline; Knöss, Werner; Kraft, Karin

2014-01-01

400

Effects of Er:YAG laser treatments on surface roughness of base metal alloys.  

PubMed

We investigated the effects of different Er:YAG laser treatments on the surface roughness of base metal alloys. A total of 36 specimens were prepared of two base metal alloys (Wiron 99, Bellabond plus). The surfaces of the specimens were standardized by gradual wet grinding with 320-, 600-, 800- and 1,000-grit silicon carbide paper for 10 s each on a grinding machine at 300 rpm. Specimens of each alloy were randomly divided into six groups (n = 6) comprising a control group (group C), a group sandblasted with Al(2)O(3) powder at 60 psi for 10 s through a nozzle at a distance of 10 mm (group S), and four Er:YAG laser (Fotona AT) treatment groups. The laser treatment groups were as follows: 500 mJ, 10 Hz, 100 ?s (group 500MSP); 500 mJ, 10 Hz, 300 ?s (group 500SP); 400 mJ, 10 Hz, 100 ?s (group 400MSP); and 400 mJ, 10 Hz, 300 ?s (group 400SP). Surface roughness measurements (Ra) were performed using a profilometer. The data were analysed by two-way ANOVA, and mean values were compared using Tukey's HSD test (? = 0.05). According to the two-way ANOVA results, the base metal alloys and interaction between base metal alloy and surface treatment were not statistically significant different (p > 0.05), the surface treatments were significantly different (p < 0.0001). For the two base metal alloy groups, no significant differences were observed among the control, 400MSP, and 400SP groups (p = 0.912), and these groups demonstrated the lowest Ra values. The highest Ra value was observed in group S (p < 0.05). Er:YAG laser treatment at 400 and 500 mJ/10 Hz is not an alternative method for surface roughening of base metal alloys. PMID:20960215

Kunt, Göknil Ergün; Güler, Ahmet Umut; Ceylan, Gözlem; Duran, Ibrahim; Ozkan, Pelin; Kirtilo?lu, Tu?rul

2012-01-01

401

New trends in instrumental design for surface plasmon resonance-based biosensors.  

PubMed

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

Abbas, Abdennour; Linman, Matthew J; Cheng, Quan

2011-01-15

402

Amplitude panning-based sound system for a horizontal surface computer: A user-based study  

Microsoft Academic Search

Given the growing popularity of multi-touch mobility devices (e.g., iPods, smartphones), the move to multi-user touch screens and horizontal surfaces is a likely trajectory of the technology. Before smart tables become widely accepted, there are many questions particularly with respect to sound production and reception and multi model interaction for these devices that need to be explored (i.e., the interaction

Jonathan Lam; Bill Kapralos; Karen Collins; Andrew Hogue; Kamen Kanev

2010-01-01

403

Grain boundaries at the surface of consolidated MgO nanocrystals and acid-base functionality.  

PubMed

The increase of the surface basicity-acidity of MgO material by factors of 1.8-3.0 due to consolidation of its nanocrystals was demonstrated by the indicator titration. It was shown that the parallel increase of surface acidity and basicity is attributed to the formation of grain boundaries (GB) after MgO aerogel densification. A simple model predicting the increase of surface acidity-basicity of MgO that correlates with the results of direct measurements was proposed. The model is based on the study of the fine atomic structure at GB surface areas in consolidated MgO nanocrystals in the framework of Density Functional Theory. It is found that the displacements of coordinatively unsaturated surface ions near the GB are significant at the distances ~3-4 atomic layers from the geometrical contact plane between nanocrystals. The detailed analysis of atomic positions inside GB demonstrated the coordination deficiency of surface atoms at the GB areas leading to the formation of stretched bonds and to creation of low coordinated surface ions due to splitting of coordination numbers of surface atoms belonging to GB areas. Density of states for electrons shows the existence of additional states in the band gap close to the bottom of the conduction band. The adsorption energy of CO2 molecules atop oxygen atoms exposed at surface GB areas is of the same order of magnitude as that reported for oxygen atoms at crystallographic edges and corners of MgO crystals. It provides additional options for bonding of molecules at the surface of nanocrystalline MgO increasing the adsorption capacity and catalytic activity. PMID:23907522

Vingurt, Dima; Fuks, David; Landau, Miron V; Vidruk, Roxana; Herskowitz, Moti

2013-09-21

404

SiGe Based Low Temperature Electronics for Lunar Surface Applications  

NASA Technical Reports Server (NTRS)

The temperature at the permanently shadowed regions of the moon's surface is approximately -240 C. Other areas of the lunar surface experience temperatures that vary between 120 C and -180 C during the day and night respectively. To protect against the large temperature variations of the moon surface, traditional electronics used in lunar robotics systems are placed inside a thermally controlled housing which is bulky, consumes power and adds complexity to the integration and test. SiGe Based electronics have the capability to operate over wide temperature range like that of the lunar surface. Deploying low temperature SiGe electronics in a lander platform can minimize the need for the central thermal protection system and enable the development of a new generation of landers and mobility platforms with highly efficient distributed architecture. For the past five years a team consisting of NASA, university and industry researchers has been examining the low temperature and wide temperature characteristic of SiGe based transistors for developing electronics for wide temperature needs of NASA environments such as the Moon, Titan, Mars and Europa. This presentation reports on the status of the development of wide temperature SiGe based electronics for the landers and lunar surface mobility systems.

Mojarradi, Mohammad M.; Kolawa, Elizabeth; Blalock, Benjamin; Cressler, John

2012-01-01

405

Surface analysis of cast aluminum by means of artificial vision and AI-based techniques  

NASA Astrophysics Data System (ADS)

An architecture for surface analysis of continuous cast aluminum strip is described. The data volume to be processed has forced up the development of a high-parallel architecture for high- speed image processing. An especially suitable lighting system has been developed for defect enhancing in metallic surfaces. A special effort has been put in the design of the defect detection algorithm to reach two main objectives: robustness and low processing time. These goals have been achieved combining a local analysis together with data interpretation based on syntactical analysis that has allowed us to avoid morphological analysis. Defect classification is accomplished by means of rule-based systems along with data-based classifiers. The use of clustering techniques is discussed to perform partitions in Rn by SOM, divergency methods to reduce the feature vector applied to the data-based classifiers. The combination of techniques inside a hybrid system leads to near 100% classification success.

Platero, Carlos; Fernandez, Carlos; Campoy, Pascual; Aracil, Rafael

1996-02-01

406

Simultaneous Sterilization With Surface Modification Of Plastic Bottle By Plasma-Based Ion Implantation  

NASA Astrophysics Data System (ADS)

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.

Sakudo, N.; Ikenaga, N.; Ikeda, F.; Nakayama, Y.; Kishi, Y.; Yajima, Z.

2011-01-01

407

Simultaneous Sterilization With Surface Modification Of Plastic Bottle By Plasma-Based Ion Implantation  

SciTech Connect

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.

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

408

Feature extraction based on contourlet transform and its application to surface inspection of metals  

NASA Astrophysics Data System (ADS)

Surface defects that affect the quality of metals are an important factor. Machine vision systems commonly perform surface inspection, and feature extraction of defects is essential. The rapidity and universality of the algorithm are two crucial issues in actual application. A new method of feature extraction based on contourlet transform and kernel locality preserving projections is proposed to extract sufficient and effective features from metal surface images. Image information at certain direction is important to recognition of defects, and contourlet transform is introduced for its flexible direction setting. Images of metal surfaces are decomposed into multiple directional subbands with contourlet transform. Then features of all subbands are extracted and combined into a high-dimensional feature vector, which is reduced to a low-dimensional feature vector by kernel locality preserving projections. The method is tested with a Brodatz database and two surface defect databases from industrial surface-inspection systems of continuous casting slabs and aluminum strips. Experimental results show that the proposed method performs better than the other three methods in accuracy and efficiency. The total classification rates of surface defects of continuous casting slabs and aluminum strips are up to 93.55% and 92.5%, respectively.

Ai, Yonghao; Xu, Ke

2012-11-01

409

A new method for measuring wetness of flowing steam based on surface plasmon resonance  

PubMed Central

A novel method for real-time and inline wetness measurement based on surface plasmon resonance (SPR) is presented in this paper. The Kretschmann geometry is adopted to excite surface plasmon waves in our measurement system. In order to prevent water coating, an ultrathin layer of hydrophobic coating is formed on the surface of Au layer. The experimental results show that the level of steam wetness can be obtained via the area ratio of water and air on the prism, which is determined by analyzing the SPR spectrum of wet steam based on a Gaussian model. In addition, during the online measurement of flowing wet steam wetness, significant shifts in the resonant position of the SPR spectrum occurred, which can be attributed to the strong interaction of the adjacent water droplets. PMID:24418483

2014-01-01

410

Design document for the Surface Currents Data Base (SCDB) Management System (SCDBMS), version 1.0  

NASA Technical Reports Server (NTRS)

The Surface Currents Database Management System (SCDBMS) provides access to the Surface Currents Data Base (SCDB) which is maintained by the Naval Oceanographic Office (NAVOCEANO). The SCDBMS incorporates database technology in providing seamless access to surface current data. The SCDBMS is an interactive software application with a graphical user interface (GUI) that supports user control of SCDBMS functional capabilities. The purpose of this document is to define and describe the structural framework and logistical design of the software components/units which are integrated into the major computer software configuration item (CSCI) identified as the SCDBMS, Version 1.0. The preliminary design is based on functional specifications and requirements identified in the governing Statement of Work prepared by the Naval Oceanographic Office (NAVOCEANO) and distributed as a request for proposal by the National Aeronautics and Space Administration (NASA).

Krisnnamagaru, Ramesh; Cesario, Cheryl; Foster, M. S.; Das, Vishnumohan

1994-01-01

411

Effects of chairside polishing and brushing on surface roughness of acrylic denture base resins  

Microsoft Academic Search

The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture\\u000a base resins were compared. Acrylic denture base resins (auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins)\\u000a were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens\\u000a were subjected to mechanical brushing using a wear tester

Seung-Kyun Kim; Ju-Mi Park; Min-Ho Lee; Jae-Youn Jung; Shipu Li; Xinyu Wang

2009-01-01

412

Design of a refractive index sensor based on surface soliton waveguides  

NASA Astrophysics Data System (ADS)

The design of an innovative integrated sensor based on superficial soliton waveguides is presented. This configuration is called a RISSOR: refractive-index surface-soliton sensor. The hybrid structure combines traditional rib waveguides with a superficial one realized by a superficial photorefractive soliton. Simulations are performed using a BPM numerical code. The sensitivity of the proposed device is based on the solitonic evanescent wave as well as the coupling between the rib and solitonic waveguides.

Fiumara, T.; Fazio, E.

2013-12-01

413

Experimental determination of photostability and fluorescence-based detection of PAHs on the Martian surface  

NASA Astrophysics Data System (ADS)

Even in the absence of any biosphere on Mars, organic molecules, including polycyclic aromatic hydrocarbons (PAHs), are expected on its surface due to delivery by comets and meteorites of extraterrestrial organics synthesized by astrochemistry, or perhaps in situ synthesis in ancient prebiotic chemistry. Any organic compounds exposed to the unfiltered solar ultraviolet spectrum or oxidizing surface conditions would have been readily destroyed, but discoverable caches of Martian organics may remain shielded in the subsurface or within surface rocks. We have studied the stability of three representative polycyclic aromatic hydrocarbons (PAHs) in a Mars chamber, emulating the ultraviolet spectrum of unfiltered sunlight under temperature and pressure conditions of the Martian surface. Fluorescence spectroscopy is used as a sensitive indicator of remaining PAH concentration for laboratory quantification of molecular degradation rates once exposed on the Martian surface. Fluorescence-based instrumentation has also been proposed as an effective surveying method for prebiotic organics on the Martian surface. We find the representative PAHs, anthracene, pyrene, and perylene, to have persistence half-lives once exposed on the Martian surface of between 25 and 60 h of noontime summer UV irradiation, as measured by fluorescence at their peak excitation wavelength. This equates to between 4 and 9.6 sols when the diurnal cycle of UV light intensity on the Martian surface is taken into account, giving a substantial window of opportunity for detection of organic fluorescence before photodegradation. This study thus supports the use of fluorescence-based instrumentation for surveying recently exposed material (such as from cores or drill tailings) for native Martian organic molecules in rover missions.

Dartnell, Lewis R.; Patel, Manish R.; Storrie-Lombardi, Michael C.; Ward, John M.; Muller, Jan-Peter

2012-05-01

414

BlueTable: Connecting Wireless Mobile Devices on Interactive Surfaces Using Vision-Based Handshaking  

E-print Network

-Based Handshaking Andrew D. Wilson Raman Sarin Microsoft Research One Microsoft Way Redmond, WA awilson process detects a phone-like object on the surface, the system follows a handshaking procedure using the idea of detecting synchronous events such as touching or bumping devices together [5, 6], or pressing

Dumais, Susan

415

Current gain in bipolar transistors with a field plate over the base surface  

E-print Network

Current gain in bipolar transistors with a field plate over the base surface V. Anantharam and K.N. Bhat Indexing terms: Bipolar transistors, Analogue simulation, Carrier lifetime, Minority carriers. Abstract: Vertical n-p-n and lateral p-n-p transistor structures of an integrated circuit are studied using

Anantharam, Venkat

416

Surface plasmon resonance based fiber optic refractive index sensor utilizing Cu/ZnO layer  

NASA Astrophysics Data System (ADS)

Modeling of a miniaturized fiber optic sensor based on surface plasmon resonance (SPR) utilizing Cu/ZnO layer is presented. Attenuated total internal reflection with Kretschmann configuration is the basis of the theoretical model. The performance of the sensor is evaluated in terms of sensitivity and detection accuracy.

Mishra, Satyendra Kr; Varshney, Charul; Gupta, Banshi D.

2013-06-01

417

An image-based retrieval algorithm of aerosol characteristics and surface reflectance for satellite images  

Microsoft Academic Search

An image-based retrieval algorithm of aerosol characteristics and surface reflectance for satellite images is proposed. By assuming the Junge size distributed aerosol in the atmosphere and feeding back the new Junge parameter, not only the aerosol optical depth but also the Junge parameter, single-scattering albedo and phase function can be iteratively derived and converged from digital counts of dense dark

C. H. LIU; A. J. CHEN; G. R. LIU

1996-01-01

418

Packet-based Ray Tracing of Catmull-Clark Subdivision Surfaces  

E-print Network

, Dylan Lacewell and Ingo Wald § Intel Corporation School of Computing, University of Utah Walt Disney Dylan Lacewell Ingo Wald Intel Corporation School of Computing, University of Utah Walt Disney surface scene containing 1.79M base faces, from Disney's Meet the Robinsons (c). Left: For reference

Wald, Ingo

419

A spline-based parameter and state estimation technique for static models of elastic surfaces  

NASA Technical Reports Server (NTRS)

Parameter and state estimation techniques for an elliptic system arising in a developmental model for the antenna surface in the Maypole Hoop/Column antenna are discussed. A computational algorithm based on spline approximations for the state and elastic parameters is given and numerical results obtained using this algorithm are summarized.

Banks, H. T.; Daniel, P. L.; Armstrong, E. S.

1983-01-01

420

Localization of Mars rovers using descent and surface-based image data  

E-print Network

image data. The Mars Pathfinder Mission in 1997 clearly demonstrated the importance of mobility systems and Golombek, 1998; Golombek et al., 1997]. In the planned 2003 Mars Exploration Rover (MER) Mission two roversLocalization of Mars rovers using descent and surface-based image data Rongxing Li, Fei Ma

Olson, Clark F.

421

Sulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor  

E-print Network

the magnitude of the sensor's response to alternating hydrogen and oxygen pulses by about 70%, as compared, either as H2 or, in the pres- ence of oxygen, as H2O. The sensor signal is obtained by monitoringSulfur surface chemistry on the platinum gate of a silicon carbide based hydrogen sensor Yung Ho

Tobin, Roger G.

422

Fiber-Optic Sensors Based on Surface Plasmon Resonance: A Comprehensive Review  

Microsoft Academic Search

Since the introduction of optical fiber technology in the field of sensor based on the technique of surface plasmon resonance (SPR), fiber-optic SPR sensors have witnessed a lot of advancements. This paper reports on the past, present, and future scope of fiber-optic SPR sensors in the field of sensing of different chemical, physical, and biochemical parameters. A detailed mechanism of

Anuj K. Sharma; Rajan Jha; B. D. Gupta

2007-01-01

423

POTENTIAL INHALATION EXPOSURE TO VOLATILE CHEMICALS IN WATER-BASED HARD-SURFACE CLEANERS  

EPA Science Inventory

Potential inhalation exposure of building occupants to volatile chemicals in water-based hard-surface cleaners was evaluated by analyzing 267 material safety data sheets (MSDSs). Among the 154 chemicals reported, 44 are volatile or semi-volatile. Hazardous air pollutants (HAPs) r...

424

Optimized synthesis of aminooxy-peptides as glycoprobe precursors for surface-based sugarprotein interaction studies  

E-print Network

. By avoiding base- containing activation mixtures which cause over-acylation, it practically suppresses of the importance of protein glycosylation as a key player in inter- and intra- cellular communication,1­4 the need available is scarce, the immobilization chemistry to the sensor chip surface must be optimal to avoid losses

Pompeu Fabra, Universitat

425

On the Design of Optimization Strategies Based on Global Response Surface Approximation Models  

Microsoft Academic Search

Striking the correct balance between global exploration of search spaces and local exploitation of promising basins of attraction is one of the principal concerns in the design of global optimization algorithms. This is true in the case of techniques based on global response surface approximation models as well. After constructing such a model using some initial database of designs it

András Sóbester; Stephen J. Leary; Andy J. Keane

2005-01-01

426

Development of biosensor systems based on surface plasmon resonance phenomenon: physical, chemical, and biological aspects  

Microsoft Academic Search

The represented work is aimed at the problem of optimization of optical biosensors based on the surface plasmon resonance (SPR) effect in thin gold films. Using it, one can characterize biomolecular interactions by detection of the resonance angle shift in a real time scale without any labels. To provide reliable operation of a sensor chip, we deposited a sensitive gold

Ekaterina V. Kostyukevich; Yuri M. Shirshov

2004-01-01

427

An effective nonlinear boundary condition for a corroding surface. Identification of the damage based  

E-print Network

, University of Delaware, Newark, DE 18716 1 #12; Corrosive Fluid f Metal Wm w Figure 1: A sketch is the corresponding thin layer of corrosive fluid, the top surface of which is assumed to be grounded. Different the determination of corrosion damage based on measurements of the boundary voltage potential and the associated

428

MESH GENERATION ON HIGH-CURVATURE SURFACES BASED ON A BACKGROUND QUADTREE STRUCTURE  

E-print Network

@tecgraf.puc-rio.br ABSTRACT This paper extends a previously proposed algorithm for generating unstructured meshes in three-dimensional unstructured meshes in three-dimensional [1] and two-dimensional [2,3] domains. The mesh is generatedMESH GENERATION ON HIGH-CURVATURE SURFACES BASED ON A BACKGROUND QUADTREE STRUCTURE Antonio C. O

Frey, Pascal

429