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1

Corrosion of orthodontic bracket bases.  

PubMed

Attention has recently been focused on the development of black and green stains in association with directly bonded stainless steel brackets. Twelve clinical cases of staining were studied in this investigation. After intraoral photography of the stains, the brackets were removed for examination with the scanning electron microscope. Multiple voids were observed at the resin-bracket interface, especially at the periphery. Considerable deterioration of the alloy base and mesh structure was observed in the void areas. Preliminary analysis of the stains showed that chromium compounds were present. The findings suggested that the presence of voids, together with poor oral hygiene, led to crevice corrosion of the Type 304 stainless steel and formation of colored corrosion products which can result in enamel stains. The use of stainless steels of improved corrosion resistance is recommended to overcome this problem. PMID:6758590

Maijer, R; Smith, D C

1982-01-01

2

Bond strength of various bracket base designs  

Microsoft Academic Search

To determine the influence of various bracket base designs on bond strength and debond interface, 6 types of metal interlock brackets of different sizes and with different base designs were evaluated. The bracket base types and mesh sizes tested were as follows: retention groove base (Dynalock, Unitek, Monrovia, Calif), circular concave base (Accuarch appliance Formula-R, Tomy, Tokyo, Japan), double mesh

Wei Nan Wang; Chung Hsing Li; Ta Hsiung Chou; Dennis Ding Hwa Wang; Li Hsiang Lin; Che Tong Lin

2004-01-01

3

Comparative evaluation of ceramic bracket base designs.  

PubMed

Since the initial introduction of ceramic brackets, base designs have been modified to reduce tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four second-generation ceramic brackets: Allure IV (A) (GAC International, Inc., Central Islip, N.Y.), Ceramaflex (C) (TP Orthodontics, Inc., LaPorte, Ind.), Intrigue (I) (Lancer Orthodontics, Carlsbad, Calif.), Transcend 2000 (T) (Unitek Corp., Monrovia, Calif.), and a foil-mesh base stainless steel bracket, DynaBond II (D) (Unitek Corp., Monrovia, Calif.). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours and the brackets were debonded with an Instron universal testing machine (Instron Corp., Canton, Mass.). A modified Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding. An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm2) necessary to debond were 174.0 (A), 71.0 (C), 189.0 (I), 228.0 (T), and 160.0 (D). Mean tensile strengths (kg/cm2) were 27.0 (A), 26.7 (C), 51.3 (I), 56.5 (T), and 48.6 (D). Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. Intrigue was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-bracket base interface for shear and tensile modes, respectively, were 80, 100 (A); 100, 90 (C); 10, 60 (I); 60, 90 (T); and 90, 80 (D).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8198079

Bordeaux, J M; Moore, R N; Bagby, M D

1994-06-01

4

Adhesion of mesh-base direct-bonding brackets.  

PubMed

The bond strength of mesh-base and metal-base brackets to human enamel was investigated for different adhesive systems. The bond strengths were determined by means of tension, shear, and torsion tests. The data were statistically analyzed and the following conclusions were drawn: 1. An adhesive system (bracket base and adhesive) cannot be selected on the basis of one test (tension, shear, or torque) alone. The various systems generally ranked differently, depending upon the test method utilized. 2. Mesh-base brackets were more retentive than the metal-base brackets in tension, while metal-base brackets were more retentive in shear. 3. For the metal-base brackets, Bond-Eze was the most retentive material, Adaptic and Orthomite followed narrowly behind, and Genie was the least retentive. 4. For the mesh-base bracket in tension and shear, Bond-Eze, Adaptic, and Solo-Tach were the most retentive materials when used with the 60-mesh base, and Genie was the least retentive. Torsion values were not useful because of a large number of bracket wing failures. PMID:285618

Thanos, C E; Munholland, T; Caputo, A A

1979-04-01

5

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

2010-11-30

6

Retention capacity of the bracket bases of new esthetic orthodontic brackets  

Microsoft Academic Search

Tensile bond strength and bond failure locations were evaluated in vitro for three types of direct bonding cements (self-cured diacrylate, dual-cured diacrylate, and dual-cured glass ionomer) with four types of brackets (stainless steel, polycarbonate, ceramic, and ceramic-polycarbonate) by using a plastic cylinder as the substrate. A highly filled, self-cured diacrylate cement gave the highest bond strength values with the polycarbonate,

Keith A. Blalock; John M. Powers

1995-01-01

7

Effect of a DPSS laser on the shear bond strength of ceramic brackets with different base designs.  

PubMed

This study evaluated the shear bond strength (SBS) and adhesive remnant index (ARI) of ceramic brackets with different base designs using a 473-nm diode-pumped solid-state (DPSS) laser to test its usefulness as a light source. A total of 180 caries-free human premolars were divided into four groups according to the base designs: microcrystalline, crystalline particle (CP), dovetail, and mesh. For each base design, teeth were divided into three different subgroups for light curing using three different light-curing units (LCUs) (quartz-tungsten-halogen unit, light-emitting diode unit, and a DPSS laser of 473 nm). Applied light intensities for the DPSS laser and the other LCUs were approximately 630 and 900 mW/cm(2), respectively. Stainless steel brackets with a mesh design served as controls. The failure modes of debonded brackets were scored using ARI. As a result, brackets bonded using the DPSS laser had the highest SBS values (16.5-27.3 MPa) among the LCUs regardless of base design. Regarding base designs, the CP groups showed the highest SBS values (22.9-27.3 MPa) regardless of LCU. Furthermore, stainless steel brackets with a mesh design had the lowest SBS values regardless of LCU. In many cases, brackets bonded using the DPSS laser had higher ARI scores and had more adhesive on their bases than on tooth surfaces. The study shows that the 473-nm DPSS laser has considerable potential for bonding ceramic brackets at lower light intensities than the other light-curing units examined. PMID:23135786

Park, Mi-Gyoung; Ro, Jung-Hoon; Park, Jeong-Kil; Ko, Ching-Chang; Kwon, Yong Hoon

2012-11-08

8

Tensile bond strength of metal bracket bonding to glazed ceramic surfaces with different surface conditionings  

PubMed Central

Objective The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments. Materials and Methods Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primer and adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively. Results The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (P<0.01). Conclusion In spite of limitations in laboratory studies it may be concluded that in application of Scotch bond multipurpose plus adhesive, phosphoric acid can be used instead of HFA for bonding brackets to the glazed ceramic restorations with enough tensile bond strength.

Akhoundi, MS. Ahmad; Kamel, M. Rahmati; Hashemi, SH. Mahmood; Imani, M.

2011-01-01

9

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

10

Shear bond strength of orthodontic brackets to aged resin composite surfaces: effect of surface conditioning.  

PubMed

The aim of this study was to investigate the effects of surface conditioning protocols on the shear bond strength (SBS) of metal brackets to aged composite resin surfaces in vitro. Ninety composite resin discs, 6 mm in diameter and 2 mm in height, were prepared and treated with an ageing procedure. After ageing, the specimens were randomly assigned to one of the following groups: (1) control with no surface treatment, (2) 38 per cent phosphoric acid gel, (3) 9.6 per cent hydrofluoric acid gel, (4) airborne aluminium trioxide particle abrasion, (5) sodium bicarbonate particle abrasion, and (6) diamond bur. The metal brackets were bonded to composite surfaces by means of an orthodontic adhesive (Transbond XT). All specimens were stored in water for 1 week at 37°C and then thermocycled (1000 cycles, 5-55°C) prior to SBS testing. SBS values and residual adhesive on the composite surface were evaluated. Analysis of variance showed a significant difference (P = 0.000) between the groups. Group 6 had the highest mean SBS (10.61 MPa), followed by group 4 (10.29 MPa). The results of this study suggest that a clinically acceptable bond strength can be achieved by surface conditioning of aged resin composite via the application of hydrofluoric acid, aluminium trioxide particle abrasion, sodium bicarbonate particle abrasion, or a diamond bur. PMID:20660131

Bayram, Mehmet; Yesilyurt, Cemal; Kusgöz, Adem; Ulker, Mustafa; Nur, Metin

2010-07-21

11

In vivo bracket retention comparison of a resin-modified glass ionomer cement and a resin-based bracket adhesive system after a year  

Microsoft Academic Search

Glass ionomer orthodontic adhesives cause less enamel demineralization during fixed orthodontic appliance treatment than do traditional resin-based products. An in vivo randomized clinical trial was performed comparing the clinical performance of a resin-modified glass ionomer (RMGI) adhesive with a no-mix, resin-based (the control) adhesive over a 12-month period. The split-mouth technique was used to analyze bracket retention, bracket failure causes,

David J. Hegarty; Tatiana V. Macfarlane

2002-01-01

12

Effects of salicylic-lactic acid conditioner on the shear bond strength of brackets and enamel surfaces.  

PubMed

The purpose of this study was to evaluate the effects of salicylic-lactic (SL) acid conditioner on the shear bond strength of brackets. Fluoride releasing (Light-bond) and non-fluoride releasing (Enlight) composite adhesives were used after conditioning with 0.22% salicylic + 9% lactic acid or 34% phosphoric acid. Composite adhesives were light cured with either a halogen light curing (HLC) unit for 30-50 s or a plasma arc curing (PAC) unit for 4 s. The shear bond strength was measured with an Instron. Failure modes of debonded brackets were identified based on adhesive remnants on the bracket and tooth. Salicylic-lactic acid conditioning was found to provide adequate shear bond strength. Groups conditioned with SL acid were debonded mainly at the enamel-resin interface and comparatively clean enamel surface after debonding was observed than those conditioned with phosphoric acid. Using confocal laser scanning microscopic examinations, it was found that demineralization patterns between SL acid and phosphoric acid conditioned groups were not different when the same adhesive was used. The SL acid conditioner did not reduce the demineralization. Light-bond adhesive showed less demineralization than Enlight adhesive. The PAC unit can be recommended as an alterative to the HLC unit because it significantly reduces the irradiation time. PMID:15790384

Chang, W-G; Lim, B-S; Yoon, T-H; Lee, Y-K; Kim, C-W

2005-04-01

13

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

PubMed

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

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

2003-05-01

14

Comparison of bond strength between simple foil mesh and laser-structured base retention brackets  

Microsoft Academic Search

The aims of the current study were to evaluate the bond strength of a new metallic orthodontic bracket with a laser structured base (Discovery, Dentaurum, Ispringen, Germany), and its effects on the site of bond failure and on the behavior of the enamel after debonding. One hundred and twenty recently extracted human premolars were bonded with 1 of 2 types

Olivier Sorel; Rafeh El Alam; Francis Chagneau; Guy Cathelineau

2002-01-01

15

CO2 laser conditioning of porcelain surfaces for bonding metal orthodontic brackets.  

PubMed

Bonding to porcelain remains to be a challenge in orthodontic treatments. The objective of this study was to evaluate the effect of CO2 laser conditioning of porcelain surfaces on shear bond strength (SBS) of orthodontic brackets. Eighty feldspathic porcelain specimens were divided into four groups of 20. In each group, half of the porcelain surfaces were deglazed, while the others remained glazed. The specimens in groups 1 to 3 were treated with a fractional CO2 laser for 10 s using 10 mJ of energy, frequency of 200 Hz and powers of 10 W (group 1), 15 W (group 2) and 20 W (group 3). In group 4, a 9.6 % hydrofluoric (HF) acid gel was used for 2 min. A silane coupling agent was applied before bracket bonding, and the SBS was measured with a universal testing machine after 24 h. Deglazing caused significant increase in SBS of laser treated porcelain surfaces (p?surfaces were compared (p?=?0.269). However, a significant between group difference was found among the deglazed specimens (p?

Ahrari, Farzaneh; Heravi, Farzin; Hosseini, Mohsen

2012-09-05

16

Compatible Poisson brackets of hydrodynamic type  

NASA Astrophysics Data System (ADS)

Some general properties of compatible Poisson brackets of hydrodynamic type are discussed, in particular: (a) an invariant differential-geometric criterion of the compatibility based on the Nijenhuis tensor which is slightly different from those existing in the literature; (b) the Lax pair with a spectral parameter governing compatible Poisson brackets in the diagonalizable case; (c) the connection of this problem with the class of surfaces in Euclidean space which possess non-trivial deformations preserving the Weingarten operator.

Ferapontov, E. V.

2001-03-01

17

Effects of different silanes and acid concentrations on bond strength of brackets to porcelain surfaces.  

PubMed

The aim of this study was to determine the optimum silane-coupling agent and the optimum concentration of acid agent when bonding to porcelain surfaces. Eighty deglazed feldspathic porcelain discs with a diameter of 10 mm and a thickness of 2 mm mounted in acrylic resin blocks were randomly divided into four groups. In groups 1 and 2, the porcelain surfaces were etched with 9.6 per cent hydrofluoric (HF) acid and in groups 3 and 4 with 5 per cent HF acid. In groups 1 and 3, the Dynalock maxillary central incisor brackets were bonded with Pulpdent silane and Unite bonding adhesive and in groups 2 and 4 with Reliance silane and Unite. Shear forces were applied to the samples using an Instron universal test machine. The non-parametric Kruskal-Wallis test was used to determine significant differences in bond strengths between the four groups and Dunn's multiple comparison test to compare subgroups. The mean bond strengths and standard deviations of groups 1 to 4 were 5.51 +/- 1.19, 6.54 +/- 0.002, 4.55 +/- 1.93, and 6.39 +/- 0.45 MPa, respectively. Specimens bonded with Reliance showed a statistically significantly higher in vitro bond strength than those bonded with Pulpdent. The concentration of etching gels did not result in any statistically significant difference on the in vitro bond strength when evaluated separately. PMID:19339674

Trakyali, Göksu; Malkondu, Ozlem; Kazazo?lu, Ender; Arun, Tülin

2009-04-01

18

In vitro orthodontic bracket bonding to porcelain.  

PubMed

This in vitro study investigated the influence of using different combinations of bracket, adhesive, and light-curing source on the tensile bond strength to porcelain and on failure patterns at debonding. Tensile tests were performed using: one ceramic bracket versus one metal bracket, two orthodontic composites; type bisphenol A-glycidyldimethacrylate and urethane dimethacrylate (UDMA), and four light-curing units with the same range of emission spectrum but various light intensities: three light-emitting diode (LED) units and one halogen-based unit. One hundred and sixty porcelain samples were randomly divided into 16 equal groups. The porcelain surface was conditioned with 9 per cent hydrofluoric acid before silane application. The composite was photo-polymerized for 40 seconds. After storage in water at 37°C for 24 hours, the samples were subjected to tensile force until bond failure. Bond strength and bond failure mode were recorded; results were analysed (? = 0.05) using R language; linear model with constant variance for the bond strength and multinomial distribution for the failure mode. The bond strength in all groups was sufficient to withstand orthodontic treatment (>6 MPa). There was no statistical difference between the adhesives, but comparing bracket × light interaction, it was significantly higher with the ceramic bracket. No significant differences were seen between the metal bracket groups, but for the ceramic bracket, the results were significantly higher with the LED light. No fracture was observed in porcelain with the metal bracket but it occurred in 35 per cent of the ceramic bracket samples and the risk was higher when using UDMA composite and lower with LED high intensity light. PMID:21447780

Al-Hity, R; Gustin, M-P; Bridel, N; Morgon, L; Grosgogeat, B

2011-03-29

19

Comparison of shear bond strength of rebonded brackets with four methods of adhesive removal.  

PubMed

Rebonding of a dislodge bracket is considered as an economic saving option which can be done with use of in-office methods or by commercial recycling. The aim of this study was to compare the shear rebond strength (SRS) of brackets recycled with different resin removal methods. Eighty premolars were divided into four experimental groups. The teeth were bonded with metal brackets. The brackets were debonded and adhesive remnants were removed from bracket bases by means of Er:YAG laser, sandblasting, direct flame, and CO2 laser, respectively. Following adhesive removal from enamel surfaces with carbide bur, recycled brackets were rebonded. Finally, all brackets were debonded with a Dartec testing machine and the SRS values were determined. The SRS values of groups 3 and 4 were significantly lower compare to other groups (P value?bracket base cleaned with Er:YAG laser irradiation. Microroughening of the base of sandblasted bracket was observed in the SEM image. Resin removal with direct flame and CO2 laser irradiation was incomplete. Er:YAG laser recycling of brackets is an efficient in-office method of reconditioning which caused minimum damage to the bracket base. PMID:23568626

Yassaei, S; Aghili, H; Khanpayeh, E; Goldani Moghadam, M

2013-04-01

20

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.

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

2013-01-01

21

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

PubMed

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

2013-01-17

22

Finite element sub-modeling analyses of damage to enamel at the incisor enamel\\/adhesive interface upon debonding for different orthodontic bracket bases  

Microsoft Academic Search

This study investigates the micro-mechanical behavior associated with enamel damage at an enamel\\/adhesive interface for different bracket bases subjected to various detachment forces using 3-D finite element (FE) sub-modeling analysis. Two FE macro-models using triangular and square bracket bases subjected to shear, tensile and torsional de-bonding forces were established using ?CT images. Six enamel\\/adhesive interface sub-models with micro- resin tag

Chun-Li Lin; Shao-Fu Huang; Hui-Chin Tsai; Wen-Jen Chang

2011-01-01

23

Load-deflection and surface properties of coated and conventional superelastic orthodontic archwires in conventional and metal-insert ceramic brackets  

PubMed Central

Background: Properties of coated archwires, which have been introduced for esthetic demands during orthodontic treatments, along with the use of tooth-colored brackets, are not clear. The aim of this study is to compare the load-deflection and surface properties of coated superelastic archwires with conventional superelastic archwires in conventional and metal-insert ceramic brackets. Materials and Methods: In this experimental study, 3 types of archwires including ultraesthetic polycoated, ultraesthetic epoxyresin coated and conventional (uncoated) superelastic nickel-titanium (NiTi) archwires were used in each of 2 types of brackets including conventional and metal-insert ceramic. To simulate oral environment, all specimens were incubated in artificial saliva using thermocycling model and then were tested in three-bracket bending test machine. Loading and unloading forces, plateau gap and end load deflection point (ELDP) were recorded. Archwires were investigated with a stereomicroscope before and after the experiment. Two-way ANOVA and Tukey tests were used at P<0.05. Results: Epoxyresin archwires produced lower forces (19 to 310 gr) compared to polycoated (61 to 359 gr) and NiTi (61 to 415 gr) (P<0.0001). The maximum ELDP (0.43 mm) was observed in epoxyresin archwires (P<0.001). Coatings of some epoxyresin wires were torn and of polycoated wires peeled off. Conventional ceramic bracket produced higher loading forces with polycoated and NiTi archwires and lower unloading forces with all 3 types of archwires compared to metal-insert type (P<0.05). Conclusion: Epoxyresin-coated archwire had the lowest force and highest ELDP. Coatings were not durable in these experimental conditions. Conventional ceramic bracket produced higher frictional force compared to metal-insert type.

Alavi, Shiva; Hosseini, Navid

2012-01-01

24

Shear bond strength of rebonded mechanically retentive ceramic brackets  

Microsoft Academic Search

The purpose of this study was to evaluate the bond strength of rebonded mechanically retentive ceramic brackets. Twenty new and 100 sandblasted rebonded ceramic brackets (Clarity, 3M Unitek, Monrovia, Calif) were bonded to 120 extracted human premolars with composite resin and divided into 6 equal groups according to how the bracket bases were treated: (1) new brackets, (2) rebonded\\/sandblasted, (3)

Chun-Hsi Chung; S. Dovid Friedman; Francis K. Mante

2002-01-01

25

Topology optimization of compressor bracket  

Microsoft Academic Search

Topology optimization is very useful engineering technique especially at the concept design stage. It is common habit to design\\u000a depending on the designer’s experience at the early stage of product development. Structural analysis methodology of compressor\\u000a bracket was verified on the static and dynamic loading condition with 2 bracket samples for the topology optimization base\\u000a model. Topology optimization is able

Jeong Woo Chang; Young Shin Lee

2008-01-01

26

Two Position Mounting Bracket for Computer Display.  

National Technical Information Service (NTIS)

A bracket for mounting a view screen fixes the screen in a retracted or a deployed position. The bracket has a base plate fixed to an upright panel. A carrier plate both swings and vertically translates on the base plate. Hinged between the base plate and...

M. J. Manceor

2003-01-01

27

Effect of flexural strength of orthodontic resin cement on bond strength of metal brackets to enamel surfaces.  

PubMed

Three types of experimental resin cements with different curing systems, dual, light, and chemical, were designed. The relationship between the flexural strengths of the three experimental and five commercial (Beauty Ortho Bond, Transbond™ XT, Light Cure Bond, Kurasper® F, and Super Bond) orthodontic resin cements on the tensile bond strength (TBS) and shear bond strength (SBS) of metal brackets to enamel was determined. Seven specimen bars of each resin were prepared for measuring the flexural strengths of the resins. Bonded specimens of each resin were prepared, seven for measuring TBS and seven SBS for after bonding of a metal bracket to a maxillary central human labial anterior tooth using experimental and commercial resin cements. The results were analysed by one-way analysis of variance and Scheffé's multiple comparison tests. The level of statistical significance was set at 0.05. Increases in the flexural strength of the resin cements were related to increases in the TBS and SBS of the metal bracket. While the light-curing cements exhibited a strong linear correlation between flexural strengths and TBS or SBS, the dual- and chemical-curing cements exhibited a different flexural strength effect on both TBS and SBS. This was a result of the adhesive layer under the metal bracket, which could be chemically cured, in contrast to the light-curing cement. To control setting time and to obtain higher initial TBS and SBS by polymerizing the resin cement under the bracket, a dual-curing system, that combines both light- and chemical-curing systems, is essential. PMID:20937669

Li, Jun

2010-10-11

28

[SIBSytem: innovation for bracket bonding?].  

PubMed

The orthodontic bracket placement has known two major improvements these last fifty years: first with the ability of bonding brackets directly on the enamel (Newmann 1965); second with the indirect bonding procedure introduced by Silvermann and Cohen in 1972. If we put aside the technological evolutions of bonding materials (brackets and adhesives), few refinements have occurred regarding the protocols in this period of time. Furthermore, direct bonding procedure seems to be used by a majority of orthodontists despite the rapidity, accuracy and ergonomics promised by indirect bonding protocol. The main originality of the system detailed in this article is to bond orthodontic brackets in a virtually predetermined position with indirect bonding advantages but with the efficiency of direct bonding because the adhesive is applied directly on the bracket base without pre-bonding necessity. This innovation has been allowed by the use of up-to-date CFAO technology. The article first describes the two components of the SIBSystem (SIBClip and SIBTray) and details the manufacturing stages. The clinical use is then evoked as well as the cautions and limits of this innovative bonding system. PMID:23719248

Moreau, Alexis

2013-05-30

29

One-step etch\\/primer for bracket bonding  

Microsoft Academic Search

A single step etch\\/primer that can be used for bonding orthodon- tic brackets with virtually any light polymerized resin-based composite bracket adhesive material that has been introduced. Clinical trials have shown it to be especially useful in re-bonding detached metallic or ceramic brackets, and for bonding brackets to fluorosed enamel. This technique report describes the PROMPT L-POP* system and demonstrates

James A. Bond; Theodore P. Croll

2001-01-01

30

Effects of Water Flow Rate on Shear Bond Strength of Orthodontic Bracket Bonded to Enamel Surface After Er:YAG Laser Ablation.  

PubMed

Abstract Objective: The aim of present study was to evaluate the effect of water flow rate on enamel surface roughness and shear bond strength (SBS) of orthodontic brackets after Er:YAG laser ablation. Background data: It is well known that external water supply is a fundamental requirement for Er:YAG laser efficiency on dental hard tissues. However, there is no consensus considering the water flow rate used during Er:YAG laser ablation. Methods: Eighty sound human upper premolar teeth were used in the present study. Seventy-six teeth were assigned into four groups according to surface treatments. The 37% phosphoric acid-etched group served as the control. Er:YAG laser irradiation was performed in three subgroups with water flow rates of 25, 36, and 48?mL/min, respectively. All specimens were subjected to a SBS test. One specimen from each different surface treatment modality was examined by scanning electron microscopy. Kruskal-Wallis test was used to compare the SBS value of each group. Results: Although the control group had the highest SBS value, statistically no significant differences were found among groups. Conclusions: Er:YAG laser application with a water flow rate of 48?mL/min produced better enamel surface alterations without any thermal damage to yield higher SBS values. PMID:24102166

Topcuoglu, Tolga; Oksayan, Ridvan; Ademci, K Ebru; Goymen, Merve; Usumez, Serdar; Usumez, Aslihan

2013-10-01

31

Shear bond strength of new and recycled brackets to enamel.  

PubMed

The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-microm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm2), brackets recycled by aluminum oxide blasting (0.34 kgf/mm2) and new brackets attached to previously bonded teeth (0.43 kgf/mm2). Brackets recycled by the specialized company (0.28 kgf/mm2) and those recycled by silicon carbide stone grinding (0.14 kgf/mm2) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/mm2) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-microm aluminum oxide particle air-abrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike. PMID:16721464

Tavares, Stenyo Wanderley; Consani, Simonides; Nouer, Darcy Flávio; Magnani, Maria Beatriz Borges de Araújo; Nouer, Paulo Roberto Aranha; Martins, Laura Moura

2006-05-02

32

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

33

Endotoxin affinity for orthodontic brackets.  

PubMed

Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue's healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and "gold" brackets were exposed to 10 EU/mm2radiolabeled Porphyromonas gingivalis or Escherichia coli lipolpoysaccharide in water and incubated for 24 hours at 37 degrees C. Brackets were then transferred to fresh lipopolysaccharide-free water and incubated for 24 hours at 37 degrees C to evaluate elution. This elution transfer was continued up to 96 hours total incubation. Lipopolysaccharide adherence and elution levels were calculated after treatment, and elution solutions were evaluated through liquid scintillation spectrometry. Mean initial lipopolysaccharide adherence ranged from 2.42 +/- 0.26 EU/mm2(E. coli, plastic) to 6.75 +/- 0.34 EU/mm2 (P. gingivalis, stainless steel). P. gingivalis lipopolysaccharide adherence was significantly greater than E. coli lipopolysaccharide adherence for all bracket types. Moreover, for each lipopolysaccharide type, stainless steel brackets exhibited significantly greater lipopolysaccharide adherence. Regarding elution, only the P. gingivalis lipopolysaccharide-exposed ceramic and plastic brackets at 24 hours and the stainless steel and ceramic brackets at 48 hours eluted measurable lipopolysaccharide. Results from this study demonstrate that P. gingivalis and E. coli LPS exhibit a high affinity for orthodontic brackets. In vivo, this affinity could affect the concentration of LPS in the gingival sulcus, thereby contributing to inflammation in tissues adjacent to the brackets. PMID:10358245

Knoernschild, K L; Rogers, H M; Lefebvre, C A; Fortson, W M; Schuster, G S

1999-06-01

34

Kauffman bracket of plane curves  

NASA Astrophysics Data System (ADS)

We lower the Kauffman bracket for links in a solid torus (see [16]) to generic plane fronts. It turns out that the bracket can be entirely defined in terms of a front itself without using the Legendrian lifting. We show that all the coefficients of the lowered bracket are in fact Vassilev type invariants of Arnold's J +-theory [3, 4]. We calculate their weight systems. As a corollary we obtain that the first coefficient is essentially the quantum deformation of the Bennequin invariant introduced recently by M. Polyak [19].

Chmutov, S.; Goryunov, V.

1996-12-01

35

Calculation of four-particle harmonic-oscillator transformation brackets  

NASA Astrophysics Data System (ADS)

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

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

2010-02-01

36

A method for producing controlled fl uoride release from an orthodontic bracket  

Microsoft Academic Search

SUMMARY The aim of this study was to manufacture and test, in vitro , a novel modifi cation to provide fl uoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.7 mm in depth) at the centre of the bracket base. Four materials, with and without the addition of sodium fl

Song Li; Ross S. Hobson; Yuxing Bai; Zhuoqun Yan; Thomas E. Carrick; John F. McCabe

37

Frictional Resistance in Self-Ligating Orthodontic Brackets and Conventionally Ligated Brackets  

Microsoft Academic Search

Objective: To compare the amount of expressed frictional resistance between orthodontic self- ligating brackets and conventionally ligated brackets in vitro as reported in the literature. Methods: Several electronic databases (Medline, PubMed, Embase, Cochrane Library, and Web of Science) were searched without limits. In vitro studies that addressed friction of self-ligating brackets compared with conventionally ligated brackets were selected and reviewed.

Sayeh Ehsani; Marie-Alice Mandich; Tarek H. El-Bialy; Carlos Flores-Mir

2009-01-01

38

Effect of pumice prophylaxis on the bond strength of orthodontic brackets  

Microsoft Academic Search

Pumice prophylaxis has long been accepted as a prerequisite for achieving adequate enamel etching during orthodontic bonding procedures. Three methods were used in this study to examine the effects of pumice prophylaxis on the bond strength of orthodontic brackets: (1) shear bond strength of brackets that were bonded to extracted premolars after surface preparation procedures, which either included or did

Steven J. Lindauer; Henry Browning; Bhavna Shroff; Frank Marshall; Ralph H. B. Anderson; Peter C. Moon

1997-01-01

39

Endotoxin affinity for orthodontic brackets  

Microsoft Academic Search

Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue’s healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and

Kent L. Knoernschild; Holly M. Rogers; Carol A. Lefebvre; Weston M. Fortson; George S. Schuster

1999-01-01

40

ESF GROUND SUPPORT - PROPOSED JACKING BRACKET EVALUATION  

SciTech Connect

This calculation applies to the Constructor's design of the proposed jacking bracket for the W6 x 20 steel set. The specific features of the jacking bracket evaluated in this analysis are the shear on the bracket bolts, and the effects of the applied moment on the W6 x 20 steel set beam segment.

Marvin D. Stine

1996-03-28

41

Debonding orthodontic ceramic brackets by ultrasonic instrumentation  

Microsoft Academic Search

Breakage of ceramic brackets because of brittleness may cause such problems as aspiration of fragments and injury by flying debris. Portions remaining on the tooth must be laboriously ground off with a handpiece. This study investigated a potential method of lowering the force required to remove ceramic brackets, i.e., use of an ultrasonic chisel. Ceramic brackets were bonded to extracted

Daniel B. Boyer; Geoffrey Engelhardt; Samir E. Bishara

1995-01-01

42

Surface Plasmon Based Spectrometer  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

43

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

44

The use of easily debondable orthodontic adhesives with ceramic brackets.  

PubMed

We experimentally produced an easily debondable orthodontic adhesive (EDA) containing heat-expandable microcapsules. The purpose of this in vitro study was to evaluate the best debondable condition when EDA was used for ceramic brackets. Shear bond strengths were measured before and after heating and were compared statistically. Temperatures of the bracket base and pulp wall were also examined during heating. Bond strengths of EDA containing 30 wt% and 40 wt% heat-expandable microcapsules were 13.4 and 12.9 MPa, respectively and decreased significantly to 3.8 and 3.7 MPa, respectively, after heating. The temperature of the pulp wall increased 1.8-3.6°C after heating, less than that required to induce pulp damage. Based on the results, we conclude that heating for 8 s during debonding of ceramic brackets bonded using EDA containing 40 wt% heat-expandable microcapsules is the most effective and safest method for the enamel and pulp. PMID:21946484

Ryu, Chiyako; Namura, Yasuhiro; Tsuruoka, Takashi; Hama, Tomohiko; Kaji, Kaori; Shimizu, Noriyoshi

2011-09-23

45

Quadratic brackets from symplectic forms  

NASA Astrophysics Data System (ADS)

We give a physicist oriented survey of Poisson-Lie symmetries of classical systems. We consider finite-dimensional geometric actions and the chiral WZNW model as examples for the general construction. An essential point is the appearance of quadratic Poisson brackets for group-like variables. It is believed that upon quantization they lead to quadratic exchange algebras. On leave from the Institute for Nuclear Research, Bulgarian Academy of Sciences, Tsarigradsko Chaussee 72, BG-1784 Sofia, Bulgaria.

Alekseev, Anton Yu.; Todorov, Ivan T.

1994-06-01

46

21 CFR 872.5470 - Orthodontic plastic bracket.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device...

2013-04-01

47

Evaluation of frictional resistance in esthetic brackets  

Microsoft Academic Search

The purpose of this study was to measure the frictional forces generated between composite, ceramic, and metal brackets and selected wire alloy-size combinations with elastomeric and stainless steel ligatures in a dry environment. Four types of composite, one ceramic, one sapphire, and one metal bracket were tested with stainless steel, nickel-titanium, and ?-titanium wires. The testing was performed with two

Eleni Bazakidou; Ram S. Nanda; Manville G. Duncanson; Pramod Sinha

1997-01-01

48

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

2006-01-20

49

Does ultra-pulse CO(2) laser reduce the risk of enamel damage during debonding of ceramic brackets?  

PubMed

This study seeks to evaluate the enamel surface characteristics of teeth after debonding of ceramic brackets with or without laser light. Eighty premolars were bonded with either of the chemically retained or the mechanically retained ceramic brackets and later debonded conventionally or through a CO(2) laser (188 W, 400 Hz). The laser was applied for 5 s with scanning movement. After debonding, the adhesive remnant index (ARI), the incidence of bracket and enamel fracture, and the lengths, frequency, and directions of enamel cracks were compared among the groups. The increase in intrapulpal temperature was measured in ten extra specimens. The data were analyzed with SPSS software. There was one case of enamel fracture in the chemical retention/conventional debonding group. When brackets were removed with pliers, incidences of bracket fracture were 45% for the chemical retention, and 15% for the mechanical retention brackets. No case of enamel or bracket fracture was seen in the laser-debonded teeth. A significant difference was observed in ARI scores among the groups. Laser debonding caused a significant decrease in the frequency of enamel cracks, compared to conventional debonding. The increase in intrapulpal temperatures was below the benchmark of 5.5 °C for all the specimens. Laser-assisted debonding of ceramic brackets could reduce the risk of enamel damage and bracket fracture, and produce the more desirable ARI scores without causing thermal damage to the pulp. However, some augmentations in the length and frequency of enamel cracks should be expected with all debonding methods. PMID:21667137

Ahrari, Farzaneh; Heravi, Farzin; Fekrazad, Reza; Farzanegan, Fahimeh; Nakhaei, Samaneh

2011-06-11

50

The Effect of Different Soft Drinks on the Shear Bond Strength of Orthodontic Brackets  

PubMed Central

Objective: It is proved that acidic soft drinks that are commonly used, have an adverse effect on dental structures, and may deteriorate oral heath of our patients and orthodontic appliances. The aim of this study was to compare the effect of yoghurt drink with other soft drinks on the shear bond strength of orthodontic brackets. Materials and Methods: Seventy-five first premolar teeth extracted for orthodontic purposes were selected and standard twin metal brackets were bonded on the center of buccal surface with No-Mix composite. The teeth were thermocycled for 625 cycles and randomly divided into five groups of artificial saliva, carbonated yoghurt drink with lactic acid base, non-carbonated yoghurt drink with lactic acid base, 7 up with citric acid base and Pepsi with phosphoric acid base. In all groups, the teeth were immersed in liquid for five-minute sessions three times with equal intervening intervals for 3 months. SBS was measured by a universal testing machine with a speed of 0.5mm/min. Data was analyzed statistically by one-way ANOVA. Results: The results showed that mean values for the shear bond strength of carbonated yoghurt drinks, non-carbonated yoghurt drinks, 7up and Pepsi groups were 12.98(±2.95), 13.26(±4.00), 16.11(±4.89), 14.73(±5.10), respectively. There was no statistically significant difference among the groups (P-value= 0.238) Conclusion: Soft drinks used in this study did not decrease the bond strength of the brackets bonded with this specific type of composite.

Omid Khoda, M.; Heravi, F.; Shafaee, H.; Mollahassani, H.

2012-01-01

51

Rankin-Cohen brackets on pseudodifferential operators  

NASA Astrophysics Data System (ADS)

Pseudodifferential operators that are invariant under the action of a discrete subgroup [Gamma] of correspond to certain sequences of modular forms for [Gamma]. Rankin-Cohen brackets are noncommutative products of modular forms expressed in terms of derivatives of modular forms. We introduce an analog of the heat operator on the space of pseudodifferential operators and use this to construct bilinear operators on that space which may be considered as Rankin-Cohen brackets. We also discuss generalized Rankin-Cohen brackets on modular forms and use these to construct certain types of modular forms.

Choie, Youngju; Lee, Min Ho

2007-02-01

52

Ceramic bracket design: An analysis using the finite element method  

Microsoft Academic Search

This investigation was designed to generate finite element models for selected ceramic brackets and graphically display the stress distribution in the brackets when subjected to arch wire torsion and tipping forces. Six commercially available ceramic brackets, one monocrystalline and five polycrystalline alumina, of twin bracket design for the permanent maxillary left central incisor were studied. Three-dimensional computer models of the

Joydeep Ghosh; Ram S. Nanda; Manville G. Duncanson; G. Fräns Currier

1995-01-01

53

Covariant Poisson Brackets for Classical Fields.  

National Technical Information Service (NTIS)

Poisson brackets that are covariant under spacetime coordinate changes are presented for relativistic field theories. The formalism described here is an alternative to the sympletic formulation of field theories and has several advantages. It applies to r...

J. E. Marsden R. Montgomery P. J. Morrison W. B. Thompson

1985-01-01

54

Corrosion of resin-bonded orthodontic brackets.  

PubMed

The objective was to identify the nature and origin of indelible black and green stains found in enamel after the removal of bonded orthodontic brackets. Several brackets were examined by scanning electron microscopy and energy-dispersive x-ray analysis. Irrespective of the type of bracket or resin, morphologic evidence of corrosion activity was found. Brackets were pitted, and in some cases large amounts of metal were missing. Cracks were found in the resin which led to sites of destruction in which structures resembling microorganisms were also found. X-ray analysis showed the presence of chromium, nickel, iron, and chlorine in significant amounts in the bonding, discolored resin. It was concluded that the cracks were favoring crevice corrosion. In the presence of organisms and a lowered pH, together with a chloride environment and an oxygen gradient, conditions conducive to corrosion are established. PMID:6758601

Gwinnett, A J

1982-06-01

55

Inducing Multilingual POS Taggers and NP Bracketers via Robust Projection Across Aligned Corpora  

Microsoft Academic Search

This paper investigates the potential for projecting linguistic annotations including part-of-speech tags and base noun phrase bracketings from one language to another via automatically word-aligned parallel corpora. First, experiments assess the accuracy of unmodified direct transfer of tags and brackets from the source language English to the target languages French and Chinese, both for noisy machine-aligned sentences and for clean

David Yarowsky; Grace Ngai

2001-01-01

56

Effects of using a new protective sealant on the bond strength of orthodontic brackets.  

PubMed

This study determines the effect of applying a new protective sealant to the enamel surface on the shear bond strengths of orthodontic brackets. Sixty teeth were randomly divided into three groups. In group 1 (control), the brackets were bonded to the etched teeth using the regular sealant. In group 2, the sealant was replaced with Pro Seal and light cured as recommended by the manufacturer; the brackets were then placed, and the adhesive was light cured. In group 3, Pro Seal was applied, the bracket with the adhesive was placed on the tooth, and both Pro Seal and the adhesive were cured simultaneously. The purpose of this modification was to reduce one of the steps during the bonding procedure. A shear force was applied at the bracket-tooth interface using a Zwick Universal Test Machine. The results of the analysis of variance (F-ratio = 1.35) indicated that the shear bond strengths of the three groups were not significantly different (P = .267) from each other. The mean shear bond strength of the control group was 4.9+/-2.1 MPa. The mean shear bond strength for teeth coated with Pro Seal and light cured followed by application and light curing of the adhesive was 4.8+/-2.3 MPa, and the mean for the teeth coated with Pro Seal and then bracket placed followed by simultaneous light curing of the sealant and the adhesive was 4.0+/-1.5 MPa. PMID:15825790

Bishara, Samir E; Oonsombat, Charuphan; Soliman, Manal M A; Warren, John

2005-03-01

57

Effects of bracket design on critical contact angle.  

PubMed

ABSTRACT Objective: To explore how the position of the bracket slots relative to the archwire influences the friction between them, and how bracket design affects the critical contact angle (?c). Materials and Methods: Two kinds of stainless steel archwires (0.016 and 0.019 × 0.025-inch) were tested against four kinds of brackets (Transmission Straight Archwire bracket, Domestic MBT bracket, Tip-Edge Plus bracket, and BioQuick self-ligation bracket) in the dry state. Resistance to sliding (RS) was measured as an increase in contact angle (?). The value of ?c was calculated by two linear regression lines. Results: Friction remained stable when ? < ?c, then increased linearly when ? > ?c. The ?c values of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket were significantly larger than those for the Domestic MBT bracket and BioQuick self-ligation bracket. Conclusions: The relationship between the archwire and bracket slot significantly affects the resistance to sliding. The "edge-off" structure of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket could help to increase the ?c value, and to expand the passive configuration range. PMID:23570249

Liu, Xiaomo; Ding, Peng; Lin, Jiuxiang

2013-04-09

58

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

2013-07-29

59

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

60

Shadow Hamiltonians, Poisson brackets, and gauge theories  

NASA Astrophysics Data System (ADS)

Numerical lattice gauge theory computations to generate gauge field configurations including the effects of dynamical fermions are usually carried out using algorithms that require the molecular dynamics evolution of gauge fields using symplectic integrators. Sophisticated integrators are commonly used but hard to optimize, and force-gradient integrators show promise especially for large lattice volumes. We explain that symplectic integrators lead to very efficient Monte Carlo algorithms because they exactly conserve a shadow Hamiltonian. The shadow Hamiltonian may be expanded in terms of Poisson brackets and can be used to optimize the integrators. We show how this may be done for gauge theories by extending the formulation of Hamiltonian mechanics on Lie groups to include Poisson brackets and shadows and by giving a general method for the practical computation of forces, force gradients, and Poisson brackets for gauge theories.

Kennedy, A. D.; Silva, P. J.; Clark, M. A.

2013-02-01

61

Torque Deformation Characteristicsof Plastic Brackets: A Comparative Study  

Microsoft Academic Search

Aim: The purpose of this study was to compare the torque deformation characteristics of seven commercially available plastic brackets, both amongst each other and with stainless steel brackets. Material and Methods: Ten brackets each of (1) pure polycarbonate, (2) ceramic reinforced polycarbonate, (3) fiberglass reinforced polycarbonate, (4) ceramic reinforced polycarbonate with metal slot, (5) fiberglass reinforced polycarbonate with metal slot,

Reza Sadat-Khonsari; Azita Moshtaghy; Volker Schlegel; Bärbel Kahl-Nieke; Mathias Möller; Oskar Bauss

2004-01-01

62

Using a Bracketed Analysis as a Learning Tool.  

ERIC Educational Resources Information Center

|Bracketed analysis is an examination of experiences within a defined time frame or "bracket." It assumes the ability to learn from any source: behaviors, emotions, rational and irrational thought, insights, reflections, and reactions. A bracketed analysis to determine what went wrong with a grant proposal that missed deadlines illustrates its…

Main, Keith

1995-01-01

63

Doubled Field Theory, T-Duality and Courant-Brackets  

NASA Astrophysics Data System (ADS)

In these lecture notes we give a simple introduction into double field theory. We show that the presence of momentum and winding excitations in toroidal backgrounds of closed string theory makes it natural to consider double field theories. A tool-kit is developed based on the Courant-bracket and generalized Lie derivatives. We construct a background independent action which represents a T-duality covariantization of the Einstein-Hilbert action for gravity coupled to an antisymmetric tensor field and a dilaton.

Zwiebach, Barton

64

A method for producing controlled fluoride release from an orthodontic bracket.  

PubMed

The aim of this study was to manufacture and test, in vitro, a novel modification to provide fluoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.7 mm in depth) at the centre of the bracket base. Four materials, with and without the addition of sodium fluoride, a glass ionomer cement (Ketac Cem micro), a resin-modified glass ionomer cement (RMGIC; GC Fuji Ortho LC), a zinc phosphate (Zinc Cement Improved), and a resin (Transbond XT) were used to fill the recess in the bracket base. Fluoride release was measured daily during the first week and then weekly for 10 weeks. An ion chromatograph with suppressed conductivity was used for free fluoride ion determination. Statistical analysis to determine the amount of flouride release was undertaken using analysis of variance and Tukey's test. During the first 2 weeks, the resin group, with the addition of 38 per cent sodium fluoride added, released significantly more free fluoride (P < 0.05), but after 2 weeks the fluoride release markedly decreased. After 5 weeks, the RMGIC group, with 15 per cent added sodium fluoride, had significantly higher (P < 0.05) daily fluoride release than the other groups. The findings demonstrated that an appropriate fluoridated material can be used as a fluoride-releasing reservoir in a modified orthodontic bracket to enable it to release fluoride over the period of fixed appliance treatment. PMID:17804428

Li, Song; Hobson, Ross S; Bai, Yuxing; Yan, Zhuoqun; Carrick, Thomas E; McCabe, John F

2007-09-04

65

Bond strength of ceramic brackets bonded to enamel with amorphous calcium phosphate-containing orthodontic composite.  

PubMed

The aim of this in vitro study was to compare the shear bond strength (SBS) and failure modes of a conventional resin-based composite with a recently developed amorphous calcium phosphate (ACP)-containing orthodontic composite system. Forty freshly extracted human maxillary premolar teeth were randomly divided into two equal groups. Conventional composite (group 1; Transbond-XT; 3M Unitek) and ACP-containing orthodontic composite (group 2; Aegis-Ortho; Harry J. Bosworth Co.) were used for bonding ceramic orthodontic brackets. The SBS of these brackets were measured and recorded in megapascals (MPa). Adhesive remnant index (ARI) scores were determined after bracket failure. Data were analysed with a Student's t-test for two independent variables and Pearson's chi-square tests. Statistical analysis showed that the bond strength of group 1 (mean: 36.7 +/- 6.8 MPa) was significantly higher than group 2 (mean: 24.2 +/- 5.4 MPa; P < 0.01). Although a greater percentage of the fractures were cohesive at the composite interface (Score 1 + Score 2 = 70 per cent in group 1 and 90 per cent in group 2), statistically significant differences were observed between the groups (P < 0.05). The ACP system is suitable for bonding ceramic orthodontic brackets due to the lower SBS values compared with conventional composite. The ACP-containing composite is recommended for use in clinical orthodontic practice in order to achieve lower decalcification scores under ceramic orthodontic brackets. PMID:20080960

Uysal, Tancan; Ustdal, Ayca; Nur, Metin; Catalbas, Bulent

2010-01-15

66

Conceptual design for PSP mounting bracket  

SciTech Connect

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

Ransom, G.; Stein, R.

1991-08-16

67

Effect of fluoride solutions on the shear bond strength of orthodontic brackets.  

PubMed

The aim of this in vitro study was to evaluate the shear bond strength of brackets after pre-treatment with different fluoride solutions. This study used 48 freshly extracted sound bovine incisors that were randomly assigned to 4 experimental groups (n=12). CG: (control) without treatment; NF: 4 min application of neutral fluoride; APF: application of 1.23% acidulated phosphate fluoride (APF) for 4 min; and SFV: application of 5% sodium fluoride varnish for 6 h. For each group, after surface treatment, prophylaxis of enamel and bracket bonding with Transbond XT composite resin (3M) were performed following the manufacturer's specifications. The shear bond strength was performed with a universal testing machine 24 h after fixing the brackets. The tooth surfaces were analyzed to verify the adhesive remnant index (ARI). Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). There was statistically significant difference among the groups (p<0.0001). CG and NF groups presented significantly higher bond strength than APF and SFV. There was no significant difference between CG and NF or between APF and SFV (p>0.05). The analysis of ARI scores revealed that most failures occurred at the enamel-resin interface. It may be concluded that the pre-treatment of enamel with 1.23% APF and 5% SFV prior to fixing orthodontic brackets reduces shear bond strength values. PMID:23338263

Leódido, Gabriela da Rocha; Fernandes, Hianna Oliveira; Tonetto, Mateus Rodrigues; Presoto, Cristina Dupim; Bandéca, Matheus Coêlho; Firoozmand, Leily Macedo

2012-01-01

68

A quantum-classical bracket that satisfies the Jacobi identity  

SciTech Connect

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

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

2006-05-28

69

Effect of brushing on fluoride release from 3 bracket adhesives  

Microsoft Academic Search

The purpose of this in vitro study was to compare fluoride ion release from 3 orthodontic bracket adhesives with and without brushing the bracketed teeth with a fluoridated dentifrice. The bracket adhesives included a light-cured composite resin (Transbond; 3M Unitek, Monrovia, Calif), a fluoride-releasing composite resin (Advance; L D Caulk Division, Dentsply International, Milford, Del), and a resin-modified glass ionomer

Robert N. Staley; Steven J. Mack; James S. Wefel; Marcos A. Vargas; Jane R. Jakobsen

2004-01-01

70

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

SciTech Connect

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

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

1989-01-01

71

The effect of constant height bracket placement on marginal ridge levelling using digitized models.  

PubMed

Bracket placement is an important phase of orthodontic treatment. Final compensatory archwire bends or bracket repositioning may be avoided if brackets are accurately positioned at the outset, so as to correctly express their built-in prescription. The purpose of this study was to investigate the levelling of marginal ridges when a bracket placement protocol, with fixed values from the incisal edges and occlusal surfaces, was used on digitized models. A computerized tool, OrthoCAD, was used to predict the end result using virtual set-up software. The appliances used for digital simulation were 3M MBT Victory Series 0.022 inch with a 0.019 x 0.025 inch stainless steel final archwire on 42 digitized models. A paired t-test was used to investigate differences between the means of the pre- (T1) and post- (T2) treatment marginal ridge heights. The results showed that most of the marginal ridge points studied deteriorated during digitized treatment prediction compared with T1. Statistical and clinically significant changes (P < 0.05) were found for upper premolar and lower molar marginal ridge points. Variability in the facial contour of the teeth seemed to play an important role. PMID:19487435

Suárez, Carlos; Vilar, Teresa

2009-06-01

72

The Poisson bracket compatible with the classical reflection equation algebra  

NASA Astrophysics Data System (ADS)

We introduce a family of compatible Poisson brackets on the space of 2 × 2 polynomial matrices, which contains the reflection equation algebra bracket. Then we use it to derive a multi-Hamiltonian structure for a set of integrable systems that includes the XXX Heisenberg magnet with boundary conditions, the generalized Toda lattices and the Kowalevski top.

Tsiganov, A. V.

2008-06-01

73

Bracketing--practical considerations in Husserlian phenomenological research.  

PubMed

Nursing research leans heavily towards naturalism, with phenomenology commonly adopted. The three main schools of phenomenology used are Husserl's descriptive approach, Heidegger's interpretive hermeneutic approach and the Dutch Utrecht School of phenomenology which combines characteristics of both. Husserl's approach--the description of ordinary human experiences as perceived by each individual--involves four main steps: bracketing, intuiting, analysing and describing. Many phenomenological nurse researchers consciously decide to adopt a Heideggerian approach because of the perceived difficulties in achieving bracketing. This paper examines the concept of bracketing (epoché) and outlines some of the practical considerations when attempting to achieve it. PMID:20222275

Hamill, Conal

2010-01-01

74

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.

Ahrari, Farzaneh; Poosti, Maryam; Motahari, Pourya

2012-01-01

75

6. DETAIL VIEW OF CONNECTION BETWEEN INLCINED COLUMNS, BRACKETED STRUTS, ...  

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

6. DETAIL VIEW OF CONNECTION BETWEEN INLCINED COLUMNS, BRACKETED STRUTS, AND SHORT COLUMN CARRYING CAST-IRON ROOF TRUSSES. - Baltimore & Ohio Railroad, Martinsburg West Roundhouse, East End of Race & Martin Streets, Martinsburg, Berkeley County, WV

76

42. Detail, subdeck viaduct showing riveted brackets supporting pedestrian walkway ...  

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

42. Detail, sub-deck viaduct showing riveted brackets supporting pedestrian walkway and heavily reinforced concrete of traffic roadway: note granite blocks atop pier. - Broadway Bridge, Spanning Foundry Street, MBTA Yard, Fort Point Channel, & Lehigh Street, Boston, Suffolk County, MA

77

21. May 1974. DETAIL VIEW OF LAMP BRACKET AND SCULPTURED ...  

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

21. May 1974. DETAIL VIEW OF LAMP BRACKET AND SCULPTURED SPRING BLOCK WITH ENGINEER OR MACHINIST. - Smithfield Street Bridge, Spanning Monongahela River on Smithfield Street, Pittsburgh, Allegheny County, PA

78

15. DETAIL OF SEGMENTALLY ARCHED BRICK PANEL WITH BRACKETED GABLE ...  

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

15. DETAIL OF SEGMENTALLY ARCHED BRICK PANEL WITH BRACKETED GABLE ON NORTH SIDE OF 1916 SECTION, TAKEN FROM THE NORTH. - James Russell Lowell Elementary School, 4501 Crittenden Drive, Louisville, Jefferson County, KY

79

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

80

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

81

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

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

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

82

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

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

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

83

Effect of muffler mounting bracket designs on durability  

Microsoft Academic Search

Automotive industries perform durability tests on vehicles in the end-user environment to reduce failures and warranty costs in the end-user hands. In this paper we present the failure analysis of muffler mounting brackets of three-wheeler vehicles observed during the durability test. Cracks at the weld location between the engine cradle and brackets were observed in all the vehicles at an

Senthilnathan Subbiah; O. P. Singh; Srikanth K. Mohan; Arockia P. Jeyaraj

2011-01-01

84

Fracture strength of ceramic brackets during arch wire torsion  

Microsoft Academic Search

This study evaluated the fracture strengths of eight new vintage ceramic brackets with application of torsional forces. Palatal root torque was applied at the distal side of right maxillary central incisor brackets with 0.022-inch slots by means of a 0.0215 × 0.027-inch rounded edge stainless steel arch wire. A specially designed apparatus that attached to an Instron machine was used

Philippe C. Aknin; Ram S. Nanda; Manville G. Duncanson; G. Fräns Currier; Pramod K. Sinha

1996-01-01

85

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

86

Nanoparticle Based Surface-Enhanced Raman Spectroscopy  

SciTech Connect

Surface-enhanced Raman scattering is a powerful tool for the investigation of biological samples. Following a brief introduction to Raman and surface-enhanced Raman scattering, several examples of biophotonic applications of SERS are discussed. The concept of nanoparticle based sensors using SERS is introduced and the development of these sensors is discussed.

Talley, C E; Huser, T R; Hollars, C W; Jusinski, L; Laurence, T; Lane, S M

2005-01-03

87

Corrosion resistance of three orthodontic brackets: a comparative study of three fl uoride mouthwashes  

Microsoft Academic Search

SUMMARY In the present study, three types of orthodontic brackets were investigated: cobalt- chromium (CoCr), iron-chromium-nickel (FeCrNi) and titanium (Ti) based. Their corrosion resistance was compared with that of platinum (Pt), which was chosen as the reference material because of its excellent electrochemical properties. The test solutions were Elmex®, Meridol® and Acorea® fl uoride mouthwashes. Fusayama Meyer artifi cial saliva

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

88

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

PubMed Central

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

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

2013-01-01

89

The Shear Bond Strengths of Metal and Ceramic Brackets: An in-Vitro Comparative Study.  

PubMed

Aim: This study has compared the Shear Bond Strengths (SBSs) of ceramic brackets and metal brackets. Materials and Method: Forty freshly extracted, human maxillary first premolars were selected for bonding. They were equally bonded with ceramic brackets (Transcend series 6000) and metal brackets (Mini Dynalock Straight wire brackets). A no - mix orthodontic adhesive system was used. Their shear bond strengths were measured by using the Instron universal machine. Results: The mean bond strength of the ceramic brackets was 20.68 ± 3.89 Mpa and that of the metal brackets was 12.15 ± 1.32 MPa. Conclusion: The shear bond strength of the ceramic brackets was found to be superior than that of the metal brackets. PMID:23998105

Reddy, Y G; Sharma, Rohit; Singh, Ammandeep; Agrawal, Vishal; Agrawal, Vijay; Chaturvedi, Saurab

2013-07-01

90

Fuzzy vector median-based surface smoothing.  

PubMed

This paper proposes a novel approach for smoothing surfaces represented by triangular meshes. The proposed method is a two-step procedure: surface normal smoothing through fuzzy vector median (FVM) filtering followed by integration of surface normals for vertex position update based on the least square error (LSE) criteria. Median and Order Statistic-based filters are extensively used in signal processing, especially image processing, due to their ability to reject outliers and preserve features such as edges and monotonic regions. More recently, fuzzy ordering theory has been introduced to allow averaging among similarly valued samples. Fuzzy ordering theory leads naturally to the fuzzy median, which yields improved noise smoothing over traditional crisp median filters. This paper extends the fuzzy ordering concept to vector-based data and introduces the fuzzy vector median filter. The application of FVM filters to surface normal smoothing yields improved results over previously introduced normal smoothing algorithms. The improved filtering results, coupled with LSE vertex position update, produces surface smoothing that minimizes the effects of noise while simultaneously preserving detail features. The proposed method is simple to implement and relatively fast. Simulation results are presented showing the performance of the proposed method and its advantages over commonly used surface smoothing algorithms. Additionally, optimization procedures for FVM filters are derived and evaluated. PMID:18579957

Shen, Yuzhong; Barner, Kenneth E

91

Fast surface design based on sketched networks  

NASA Astrophysics Data System (ADS)

Computer aided design of freeformed surfaces is strongly biased towards input and optimization of surfaces. Input modules are based on digitizing drawings or placing and manipulating spline control vertices. Design, especially during the idea generation (or conceptual) design phase, is poorly supported. We present a system based on direct manipulation of shaded images of the surfaces. The designer sketches profiles on a tablet. The profiles are positioned in object space with a spaceball (6D joystick). A network of crossing curves is built interactively. The system constructs patches over this network in realtime. The designer can correct a profile by sketching. The affected surfaces are updated immediately. Patches are defined by the curves and estimated cross-boundary derivatives. They connect with G1 continuity. Our prototype surface modeler avoids the need for exact dimensions and precise coordinates, as seen in traditional systems. Instead, it supports fast, intuitive generation and evaluation of surfaces. We discuss a comparison with other systems regarding the time needed to model shapes, and some opinions of professional industrial designers.

van Dijk, Casper G.

1992-11-01

92

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

93

An anatomically based surface EMG model  

Microsoft Academic Search

A model of the surface EMG signal based on a realistic arm anatomy is presented. A finite element volume conductor model was developed using magnetic resonance (MR) images of the upper arm of a healthy male subject. The model includes both resistive and capacitive material properties. To examine the ability of the model to predict the potential distribution around the

M. M. Lowery; N. S. Stoykov; T. A. Kuiken

2003-01-01

94

Almost Poisson brackets for nonholonomic systems on Lie groups  

NASA Astrophysics Data System (ADS)

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

Garcia-Naranjo, Luis Constantino

95

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.

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

2013-01-01

96

The friction and wear patterns of orthodontic brackets and archwires in the dry state  

Microsoft Academic Search

Frictional resistance at the bracket-archwire interface has been demonstrated to impede tooth movement when sliding mechanics are used. Thus, the coefficients of friction of titanium and stainless steel brackets used in conjunction with stainless and ion-implanted beta-titanium archwires were investigated using a single contact interface between the brackets and archwires. The wear patterns between the brackets and the .016- in

D. J. Michelberger; Reg L. Eadie; M. Gary Faulkner; Kenneth E. Glover; Narasimha G. Prasad; Paul W. Major

2000-01-01

97

STRUCTURE SENSE IN HIGH SCHOOL ALGEBRA: THE EFFECT OF BRACKETS  

Microsoft Academic Search

This paper presents an initial attempt to define structure sense for high school algebra and to test part of this definition. A questionnaire was distributed to 92 eleventh grade students in order to identify those who use structure sense. Presence and absence of brackets was examined to see how they affect use of structure sense. The overall use of structure

Maureen Hoch; Tommy Dreyfus

98

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

99

Investigations in a Simplified Bracketed Grid Approach to Metrical Structure  

ERIC Educational Resources Information Center

|In this dissertation, I examine the fundamental mechanisms and assumptions of the Simplified Bracketed Grid Theory (Idsardi 1992) in two ways: first, by comparing it with Parametric Metrical Theory (Hayes 1995), and second, by implementing it in the analysis of several case studies in stress assignment and syllabification. Throughout these…

Liu, Patrick Pei

2010-01-01

100

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

101

Surface metrology system based on bidirectional microdisplays  

Microsoft Academic Search

Typical optical metrology systems for surface and shape characterization are based on a separated camera and projection unit, yielding to a limitation concerning the miniaturization of the sensor. We present a compact, highly integrated optical distance sensor applying the inverse confocal principle using a bidirectional OLED microdisplay (BiMiD). This microdisplay combines light emitting device (AM-OLED microdisplay) and photo sensitive detectors

Constanze Grossmann; Franziska Perske; Susanne Zwick; Judith Baumgarten; Bernd Richter; Stefan Riehemann; Uwe Vogel; Gunther Notni; Andreas Tünnermann

2011-01-01

102

Generating Surface Textures based on Cellular Networks  

Microsoft Academic Search

This paper describes a method allowing the automatic multi-tex- turing and simulation of surface imperfections based on a cellu- lar network. In this representation, networks of connected cells are constructed in a natural and dynamic way allowing simulta- neously real-time and multi-behavior simulation. We also intro- duce an original technique to store cells in space in a fast and boundless

Stéphane Gobron; Denis Finck

2006-01-01

103

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

PubMed

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

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

2013-04-19

104

Principal Component Based Diffeomorphic Surface Mapping  

PubMed Central

We present a new diffeomorphic surface mapping algorithm under the framework of large deformation diffeomorphic metric mapping (LDDMM). Unlike existing LDDMM approaches, this new algorithm reduces the complexity of the estimation of diffeomorphic transformations by incorporating a shape prior in which a nonlinear diffeomorphic shape space is represented by a linear space of initial momenta of diffeomorphic geodesic flows from a fixed template. In addition, for the first time, the diffeomorphic mapping is formulated within a decision-theoretic scheme based on Bayesian modeling in which an empirical shape prior is characterized by a low dimensional Gaussian distribution on initial momentum. This is achieved using principal component analysis (PCA) to construct the eigenspace of the initial momentum. A likelihood function is formulated as the conditional probability of observing surfaces given any particular value of the initial momentum, which is modeled as a random field of vector-valued measures characterizing the geometry of surfaces. We define the diffeomorphic mapping as a problem that maximizes a posterior distribution of the initial momentum given observable surfaces over the eigenspace of the initial momentum. We demonstrate the stability of the initial momentum eigenspace when altering training samples using a bootstrapping method. We then validate the mapping accuracy and show robustness to outliers whose shape variation is not incorporated into the shape prior.

Younes, Laurent; Miller, Michael I.

2013-01-01

105

Principal component based diffeomorphic surface mapping.  

PubMed

We present a new diffeomorphic surface mapping algorithm under the framework of large deformation diffeomorphic metric mapping (LDDMM). Unlike existing LDDMM approaches, this new algorithm reduces the complexity of the estimation of diffeomorphic transformations by incorporating a shape prior in which a nonlinear diffeomorphic shape space is represented by a linear space of initial momenta of diffeomorphic geodesic flows from a fixed template. In addition, for the first time, the diffeomorphic mapping is formulated within a decision-theoretic scheme based on Bayesian modeling in which an empirical shape prior is characterized by a low dimensional Gaussian distribution on initial momentum. This is achieved using principal component analysis (PCA) to construct the eigenspace of the initial momentum. A likelihood function is formulated as the conditional probability of observing surfaces given any particular value of the initial momentum, which is modeled as a random field of vector-valued measures characterizing the geometry of surfaces. We define the diffeomorphic mapping as a problem that maximizes a posterior distribution of the initial momentum given observable surfaces over the eigenspace of the initial momentum. We demonstrate the stability of the initial momentum eigenspace when altering training samples using a bootstrapping method. We then validate the mapping accuracy and show robustness to outliers whose shape variation is not incorporated into the shape prior. PMID:21937344

Qiu, Anqi; Younes, Laurent; Miller, Michael I

2011-09-19

106

Plasma arc curing of ceramic brackets: an evaluation of shear bond strength and debonding characteristics.  

PubMed

The aim of this in vitro investigation was to evaluate bond strength and debonding characteristics when a xenon plasma arc curing light is used to bond polycrystalline and monocrystalline ceramic brackets. Brackets were bonded to 240 extracted bovine mandibular incisors with a composite adhesive. Curing intervals of 1, 3, and 6 seconds were chosen for curing with the plasma arc light, and the control group was cured at 10 seconds per bracket with a conventional halogen light. Debonding was performed on a universal testing machine and according to the bracket manufacturers' recommendations. Both the polycrystalline and the monocrystalline brackets consistently debonded at the bracket-adhesive interface, regardless of debonding method, curing interval, or curing light. No enamel fractures were observed after debonding. Bracket fractures were rare and did not affect debonding. Bond strength was significantly higher for the monocrystalline brackets (P <.0001): mean shear bond strength ranged between 9.68 +/- 2.17 MPa (plasma arc curing light, 1 sec curing interval) and 10.73 +/- 3.22 MPa (halogen light, 10 sec curing interval) for the polycrystalline brackets and between 19.85 +/- 2.97 MPa (plasma arc curing light, 1 sec curing interval) and 22.94 +/- 3.20 MPa (plasma arc curing light, 3 sec curing interval) for the monocrystalline brackets. Significant differences were also found for the curing methods used (P =.047). A curing interval of 3 seconds with the plasma arc curing light is recommended for both polycrystalline and monocrystalline ceramic brackets. PMID:12970665

Klocke, Arndt; Korbmacher, Heike M; Huck, Lothar G; Ghosh, Joydeep; Kahl-Nieke, Bärbel

2003-09-01

107

Lax Pairs for Equations Describing Compatible Nonlocal Poisson Brackets of Hydrodynamic Type and Integrable Reductions of the Lamé Equations  

Microsoft Academic Search

We solve the problem of describing compatible nonlocal Poisson brackets of hydrodynamic type. We prove that for nonsingular pairs of compatible nonlocal Poisson brackets of hydrodynamic type, there exist special local coordinates such that the metrics and the Weingarten operators of both brackets are diagonal. The nonlinear evolution equations describing all nonsingular pairs of compatible nonlocal Poisson brackets of hydrodynamic

O. I. Mokhov

2004-01-01

108

Fractional Dirac bracket and quantization for constrained systems  

NASA Astrophysics Data System (ADS)

So far, it is not well known how to deal with dissipative systems. There are many paths of investigation in the literature and none of them present a systematic and general procedure to tackle the problem. On the other hand, it is well known that the fractional formalism is a powerful alternative when treating dissipative problems. In this paper, we propose a detailed way of attacking the issue using fractional calculus to construct an extension of the Dirac brackets in order to carry out the quantization of nonconservative theories through the standard canonical way. We believe that, by using the extended Dirac bracket definition, it will be possible to analyze more deeply gauge theories starting with second-class systems.

Abreu, Everton M. C.; Godinho, Cresus F. L.

2011-08-01

109

Stresses developed during clinical debonding of stainless steel orthodontic brackets.  

PubMed

The purpose of this project was to use finite element modeling to calculate and compare the peak stresses generated during clinical debonding of resin bonded brackets. Five debonding techniques were considered: tension, shear-peel, torsion loads on the bracket, wedging of the cement margin, and bracket temperature increase. The data is presented in terms of the relative potentials of the methods for causing enamel fracture. That is, in this idealized model, it was assumed that enamel failures were governed by maximum principal or shear stress. Therefore, all debonding loads and calculated stresses were scaled to correspond to unit peak principal stress or unit peak shear stress in enamel. Furthermore, it was assumed that cement cohesive failure was also governed by maximum principal or maximum shear stress and that adhesive failures were caused by interface normal or shear stress. Thus, for example, it was found that for 1.0 MPa of peak shear stress in enamel, tension and shear-peel debonding generate, respectively, 1.34 and 0.96 MPa of peak normal (tensile) stress in the cement at the enamel-cement interface. The interpretation of this information is that tension debonding is less likely to cause enamel damage than shear-peel loading if it is assumed that (1) the enamel would fail due to the high shear stress, and (2) the joint would fail at the enamel-cement interface because its normal stress limit has been exceeded. PMID:9046398

Katona, T R

1997-01-01

110

Shear bond strength of orthodontic brackets bonded with light-emitting diode curing units at various polymerization times  

Microsoft Academic Search

Light emitting diode (LED) light-curing units have recently been used to polymerize resin-based orthodontic adhesives, and preliminary studies indicate their use has been successful. The purpose of this study was to evaluate the relationship between the shear bond strength of orthodontic brackets bonded to enamel and the duration of photopolymerization with LEDs and conventional quartz-tungsten-halogen light-curing units. Three LED light-curing

Timothy Swanson; William J Dunn; Darrell E Childers; Louis J Taloumis

2004-01-01

111

A smart car for the surface shape measurement of large antenna based on laser tracker  

NASA Astrophysics Data System (ADS)

The geometric accuracy of the surface shape of large antenna is an important indicator of antenna’s quality. Currently, high-precision measurement of large antenna surface shape can be performed in two ways: photogrammetry and laser tracker. Photogrammetry is a rapid method, but its accuracy is not enough good. Laser tracker can achieve high precision, but it is very inconvenient to move the reflector (target mirror) on the surface of the antenna by hand during the measurement. So, a smart car is designed to carry the reflector in this paper. The car, controlled by wireless, has a small weight and a strong ability for climbing, and there is a holding bracket gripping the reflector and controlling reflector rise up and drop down on the car. During the measurement of laser tracker, the laser beam between laser tracker and the reflector must not be interrupted, so two high-precision three-dimensional miniature electronic compasses, which can real-time monitor the relative angle between the holding bracket and the laser tracker’s head, are both equipped on the car and the head of laser tracker to achieve automatic alignment between reflector and laser beam. With the aid of the smart car, the measurement of laser tracker has the advantages of high precision and rapidity.

Gu, Yonggang; Hu, Jing; Jin, Yi; Zhai, Chao

2012-09-01

112

Systematic Uncertainties of Glacial Chronologies Based on Surface Exposure Dating  

NASA Astrophysics Data System (ADS)

Surface exposure dating using terrestrial cosmogenic nuclides provides the opportunity to establish glacial chronologies in semi-arid high mountain regions, where the lack of organic material for radiocarbon dating has limited our knowledge about the timing and the causes of glacial advances so far. However, several scaling systems and calculation schemes exist. This can result in significant systematic uncertainties, particularly at high altitudes as e.g. in the Central Andes. We present and discuss previously published exposure ages from Bolivia and Argentina in order to illustrate the extent of the current uncertainties. It is neither possible to unambiguously determine whether the local Last Glacial Maximum (local LGM) in the tropics occurred in-phase with or predated the global LGM, nor can the subsequent Late Glacial stages be dated accurately enough to infer temperature or precipitation changes at millennial-scale timescales. We then also present new results from the Tres Lagunas in the Sierra de Santa Victoria, NW Argentina. There we can compare our glacial exposure age chronology with bracketing radiocarbon ages from lake sediments. The Tres Lagunas may thus serve as a high-altitude calibration site for 10Be dating. Paleoclimatically, we conclude that glacial deposits in NW-Argentina document glacial advances in-phase with the global LGM, but that the prominent moraines there date to the Late Glacial. This coincides with the well-documented intensification and/or southward shift of the tropical circulation and reflects the strong precipitation-sensitivity of glaciers in arid and semi-arid environments.

Ilgner, J.; Zech, R.; Baechtiger, C.; Kubik, P. W.; Veit, H.

2008-12-01

113

Surface metrology system based on bidirectional microdisplays  

NASA Astrophysics Data System (ADS)

Typical optical metrology systems for surface and shape characterization are based on a separated camera and projection unit, yielding to a limitation concerning the miniaturization of the sensor. We present a compact, highly integrated optical distance sensor applying the inverse confocal principle using a bidirectional OLED microdisplay (BiMiD). This microdisplay combines light emitting device (AM-OLED microdisplay) and photo sensitive detectors (photodiode matrix) on one single chip based on OLED-on-CMOS-technology. Comparable to conventional confocal sensors, the object is shifted through the focal plane (+/-?z) and the back reflected/scattered light is collected via an special designed optic and detected by the photo sensitive detector elements. The detected photocurrent depends on movement (?z) of the measurement plane. In contrast to conventional confocal sensors, our inverse confocal sensor detects a minimum of reflected/scattered light if the object is positioned in the focal plane. We present a novel sensor concept as well as system and optical simulations that demonstrate the principle of the novel inverse confocal sensor setup.

Grossmann, Constanze; Perske, Franziska; Zwick, Susanne; Baumgarten, Judith; Richter, Bernd; Riehemann, Stefan; Vogel, Uwe; Notni, Gunther; Tünnermann, Andreas

2011-09-01

114

Torque expression of 0.018 and 0.022 inch conventional brackets.  

PubMed

The aim of this study was to assess the effect of the moments generated with low- and high-torque brackets. Four different bracket prescription-slot combinations of the same bracket type (Mini Diamond® Twin) were evaluated: high-torque 0.018 and 0.022 inch and low-torque 0.018 and 0.022 inch. These brackets were bonded on identical maxillary acrylic resin models with levelled and aligned teeth and each model was mounted on the orthodontic measurement and simulation system (OMSS). Ten specimens of 0.017×0.025 inch and ten 0.019×0.025 inch stainless steel archwires (ORMCO) were evaluated in the low- and high-torque 0.018 inch and 0.022 inch brackets, respectively. The wires were ligated with elastomerics into the brackets and each measurement was repeated once after religation. Two-way analysis of variance and t-test were conducted to compare the generated moments between wires at low- and high-torque brackets separately. The maximum moment generated by the 0.017×0.025 inch stainless steel archwire in the 0.018 inch brackets at +15 degrees ranged from 14.33 and 12.95 Nmm for the high- and low-torque brackets, respectively. The measured torque in the 0.022 inch brackets with the 0.019×0.025 inch stainless steel archwire was 9.32 and 6.48 Nmm, respectively. The recorded differences of maximum moments between the high- and low-torque series were statistically significant. High-torque brackets produced higher moments compared with low-torque brackets. Additionally, in both high- and low-torque configurations, the thicker 0.019×0.025 inch steel archwire in the 0.022 inch slot system generated lower moments in comparison with the 0.017×0.025 inch steel archwire in the 0.018 inch slot system. PMID:22828075

Sifakakis, Iosif; Pandis, Nikolaos; Makou, Margarita; Eliades, Theodore; Katsaros, Christos; Bourauel, Christoph

2012-07-24

115

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

Microsoft Academic Search

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

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

1995-01-01

116

Compatibility, Multi-brackets and Integrability of Systems of PDEs  

Microsoft Academic Search

We establish an efficient compatibility criterion for a system of generalized complete intersection type in terms of certain\\u000a multi-brackets of differential operators. These multi-brackets generalize the higher Jacobi-Mayer brackets, important in the\\u000a study of evolutionary equations and the integrability problem. We also calculate Spencer ?-cohomology of generalized complete intersections and evaluate the formal functional dimension of the solutions space. The

Boris Kruglikov; Valentin Lychagin

2010-01-01

117

Shear, torsional, and tensile bond strengths of ceramic brackets using three adhesive filler concentrations.  

PubMed

The effect of changes in adhesive filler concentration on the shear, torsional, and tensile bond strength of a chemical, a mechanical, and a chemical/mechanical retained ceramic bracket was evaluated. Two hundred ten bovine teeth were bonded with one of three ceramic brackets using a 30%, 55%, or 80% filled adhesive. The brackets were debonded with a shear, torsional, or tensile force to test the bond strength and the site of bond failure. No significant difference was found in the shear, torsional, or tensile bond strength of each ceramic bracket type in relation to changes in the adhesive filler concentration. However, there was a trend toward increased bond strength with increasing filler concentration. Combining the data according to adhesive type revealed that the 80% filled adhesive displayed a significantly greater shear bond strength than the 30% or 55% filled adhesive and a greater torsional bond strength than the 30% filled adhesive. This supports the hypothesis of increased bond strength with increased adhesive filler concentration. The mechanically retained ceramic bracket showed greater shear bond strength and maximum shear bond strength in torsion than the chemical or chemical/mechanical retained ceramic bracket. The tensile bond strength of the mechanically retained ceramic bracket was similar to that of metal brackets reported in other studies, and the failure site was at the bracket-adhesive interface. PMID:1877551

Ostertag, A J; Dhuru, V B; Ferguson, D J; Meyer, R A

1991-09-01

118

The effect on the tensile bond strength of orthodontic brackets of titanium tetrafluoride (TiF 4) application after acid etching  

Microsoft Academic Search

Titanium tetrafluoride (TiF4) was applied to acid-etched enamel surfaces to study the effect on surface structure and tensile bond strength of orthodontic brackets. Three groups of 20 premolars each were compared in debonding tests. Group l received a 1% and Group ll received a 4% topical TiF4 treatment after acid etching. Group lIl served as control, that is, no fluoride

Tamer Büyükyilmaz; Bjørn Øgaard; Sverre Dahm

1995-01-01

119

Carbon nanotube-based robust steamphobic surfaces.  

PubMed

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

Badge, Ila; Sethi, Sunny; Dhinojwala, Ali

2011-11-22

120

Variational approach for the fusion of exposure bracketed pairs.  

PubMed

When taking pictures of a dark scene with artificial lighting, ambient light is not sufficient for most cameras to obtain both accurate color and detail information. The exposure bracketing feature usually available in many camera models enables the user to obtain a series of pictures taken in rapid succession with different exposure times; the implicit idea is that the user picks the best image from this set. But in many cases, none of these images is good enough; in general, good brightness and color information are retained from longer-exposure settings, whereas sharp details are obtained from shorter ones. In this paper, we propose a variational method for automatically combining an exposure-bracketed pair of images within a single picture that reflects the desired properties of each one. We introduce an energy functional consisting of two terms, one measuring the difference in edge information with the short-exposure image and the other measuring the local color difference with a warped version of the long-exposure image. This method is able to handle camera and subject motion as well as noise, and the results compare favorably with the state of the art. PMID:23047876

Bertalmío, Marcelo; Levine, Stacey

2012-10-02

121

Effects of buccal and lingual enamel sandblasting on shear bond strength of orthodontic brackets bonded with a self-etching primer.  

PubMed

The purpose of this study was to evaluate the effects of sandblasting on the initial shear bond strength (SBS) and on the bracket/adhesive failure mode of orthodontic brackets bonded on buccal and lingual enamel using a self-etching primer (SEP). The brackets were bonded using a SEP and composite resin on the buccal and lingual surfaces of 30 premolars with intact enamel and 30 premolars pretreated by sandblasting with 50 ?m aluminum-oxide. Student's paired t-test was used to compare the groups for differences in SBS and a multiple Chi(2) test was performed to compare the bond failure mode. It was shown that sandblasting increases significantly SBS of the SEP on the buccal surfaces but the increase on the lingual surfaces is not statistically significant. A comparison of the adhesive remnant index scores indicated that there was more residual adhesive remaining on the teeth that were treated by sandblasting than on the teeth with intact enamel. Besides, there is no statistical difference between SBS of the SEP on buccal and lingual surfaces with intact enamel. Therefore, we can conclude that sandblasting improves the bond between buccal and lingual enamel and resin ant that the SEP provides the same SBS on buccal and lingual intact surfaces. PMID:23142141

Mati, Myriam; Amm, Elie; Bouserhal, Joseph; Bassil-Nassif, Nayla

2012-11-09

122

Compatible Nonlocal Poisson Brackets of Hydrodynamic Type and Integrable Reductions of the LAMÉ Equations  

Microsoft Academic Search

The problem of description for compatible nonlocal Poisson brackets of hydrodynamic type is solved. The nonlinear equations describing all compatible nonlocal Poisson brackets of hydrodynamic type are derived and the integrability of these equations by the method of the inverse scattering problem is proved. A Lax pair with a spectral parameter is found for these nonlinear equations. In the special

O. I. Mokhov

2003-01-01

123

Evaluation of the debonding strength of orthodontic brackets using three different bonding systems  

Microsoft Academic Search

SUMMARY The aim of this work was to investigate the stability of the bracket - adhesive - enamel interface, as a function of adhesive material and of debonding procedure, in order to assess which debonding technique is the least detrimental to the enamel. Ninety lower adult bovine incisors were selected and metallic orthodontic brackets were bonded using three adhesive systems:

R. Valletta; D. Prisco; R. De Santis; L. Ambrosio; R. Martina

2007-01-01

124

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

PubMed Central

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

Kim, Joo Hyoung; Cha, Jung Yul

2012-01-01

125

Field Test of an Experimental Bracketing Sight for the M16A1 Rifle.  

National Technical Information Service (NTIS)

A field experiment was conducted to determine whether a circular bracketing sight, framing the front sight on a standard rifle, could enhance the effectiveness of the rifle system in short range, quick reaction type engagements. Two bracket sizes (1.32 an...

W. G. Kemple J. W. McKinney

1971-01-01

126

Effect of enamel laser irradiation at different pulse settings on shear bond strength of orthodontic brackets.  

PubMed

Abstract Objective: To compare the effect of laser irradiation at two different pulse settings and acid etching on the shear bond strength (SBS) of orthodontic brackets to enamel. Materials and Methods: Thirty-six premolars were allocated to three groups (n ?=? 12): (1) 37% phosphoric acid etching, (2) erbium-doped yttrium aluminum garnet (Er:YAG) laser etching with medium-short pulse mode (MSP; 100 µs, 120 mj, 10 Hz, 1.2 W), and (3) Er:YAG laser etching with quantum-square pulse mode (QSP; 120 mj, 10 Hz, 1.2 W). Metallic brackets were bonded with Transbond XT. After photopolymerization, the samples were subjected to 5000 thermal cycles and debonded with a universal testing machine, and the SBS values were recorded. Surface morphology was evaluated with profilometric examination, scanning electron microscopy, and atomic force microscopy. The adhesive remnant index (ARI) was evaluated to assess the remaining adhesive. Results: The results of SBS testing were analyzed by one-way analysis of variance and Tukey honestly significant diffference tests. The mean SBS values of QSP and MSP laser groups were 11.80 ± 2.7 MPa and 10.10 ± 4.5 MPa, respectively, and the QSP group demonstrated significantly higher SBS (P < .01) than that of the acid-etched group (6.6 ± 2.4 MPa). No significant difference was observed between the SBS values of the two laser groups (P < .05). The difference between the ARI scores of the laser groups and the acid-etched group was statistically significant (P < .05). Conclusion: Laser etching at MSP and QSP modes present successful alternatives to acid etching; however, long-term clinical studies are required to verify clinical success. PMID:23763542

Sa??r, Serkan; Usumez, Asl?han; Ademci, Ebru; Usumez, Serdar

2013-06-13

127

Cytotoxic effects of the nickel release from the stainless steel brackets: An in vitro study  

PubMed Central

Aims: The purpose of the study is to determine whether the nickel released from the stainless steel brackets have any cytotoxic effects on gingival fibroblast. Materials and Methods: Brackets are an important component of fixed orthodontics. Orthodontists are mainly concerned about the brands and various systems incorporated into the brackets. The manufactures claim bracket superiority without valid research. Since we are dealing with a biologic system factors like biocompatibility, cytotoxic potential should be taken into consideration before selecting an appliance to the patient. The cytotoxic activity of the media was investigated with MTT and comet assay. Results: The results of the study show that the amount of nickel leached is capable of bringing damage to the fibroblast. Conclusion: Our study concludes that nickel solution at minimal concentration of 1.18 ?g could damage human gingival fibroblast and the nickel released from the different brands of the brackets are not uniform.

Pillai, Ajith Rajasekharan; Gangadharan, Anil; Gangadharan, Jithin; Kumar, Nallasamy Vijaya

2013-01-01

128

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

129

Comparison of shear bond strength of orthodontic brackets bonded with light emitting diode (LED).  

PubMed

Light-emitting diode (LED) light curing units (LCU) have recently been used to polymerize resin-based orthodontic adhesives and preliminary studies indicate their use has been successful. The objectives of this study were to evaluate the shear bond strength (SBS) oforthodontic brackets bonded to enamel with a LED LCU (LEDMAX 4, Hilux, Kulzer comp.) at 10, 20 and 40 seconds and comparing them with that of 40 seconds light exposure from a conventional halogen-based LCU (Hilux unit, Heraeus Kulzer comp.). Also to assess the amount of adhesive remaining on the tooth after debonding using Adhesive Remnant Index (ARI). 120 extracted human premolars were divided into 4 groups of 30 each. After photo polymerization, all the samples were stored in distilled water at 37 degrees C for 24 hours and then subjected to a shear force with universal testing machine until bracket failure. All the recordings were evaluated statistically ANOVA and Turkey tests revealed that, no statistically significant differences were found among the shear bond strengths of 40 sec halogen (10.15 +/- 1.55), 20 sec LED (9.58 +/- 1.71) and 40 sec LED (10.34 +/- 1.83) cured groups; but the bond strength of 10 sec cure LED group (7.56 +/- 1.47) showed significantly lower than the other groups. Chi-square comparisons indicated that there were no significant differences in the ARI scores between the 4 groups tested. The results of this study are promising for orthodontic application of LED curing units in clinics, but further in vivo trials should be performed before validation. PMID:21314086

Rachala, Madhukar Reddy; Yelampalli, Muarlidhar Reddy

2010-01-01

130

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

SciTech Connect

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

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

2011-06-01

131

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

132

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

Microsoft Academic Search

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

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

2004-01-01

133

Correction of palatally displaced maxillary lateral incisors without brackets.  

PubMed

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

Choi, Kyung-Hee; Lee, Yoonjung; Kim, Minji; Chun, Youn-Sic

2013-08-22

134

Patterned superhydrophobic surface based on Pd-based metallic glass  

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

135

SURFACE PROPERTIES OF SOY-BASED POLYSOAPS  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

136

Surface similarity-based molecular query-retrieval  

PubMed Central

Background Discerning the similarity between molecules is a challenging problem in drug discovery as well as in molecular biology. The importance of this problem is due to the fact that the biochemical characteristics of a molecule are closely related to its structure. Therefore molecular similarity is a key notion in investigations targeting exploration of molecular structural space, query-retrieval in molecular databases, and structure-activity modelling. Determining molecular similarity is related to the choice of molecular representation. Currently, representations with high descriptive power and physical relevance like 3D surface-based descriptors are available. Information from such representations is both surface-based and volumetric. However, most techniques for determining molecular similarity tend to focus on idealized 2D graph-based descriptors due to the complexity that accompanies reasoning with more elaborate representations. Results This paper addresses the problem of determining similarity when molecules are described using complex surface-based representations. It proposes an intrinsic, spherical representation that systematically maps points on a molecular surface to points on a standard coordinate system (a sphere). Molecular surface properties such as shape, field strengths, and effects due to field super-positioningcan then be captured as distributions on the surface of the sphere. Surface-based molecular similarity is subsequently determined by computing the similarity of the surface-property distributions using a novel formulation of histogram-intersection. The similarity formulation is not only sensitive to the 3D distribution of the surface properties, but is also highly efficient to compute. Conclusion The proposed method obviates the computationally expensive step of molecular pose-optimisation, can incorporate conformational variations, and facilitates highly efficient determination of similarity by directly comparing molecular surfaces and surface-based properties. Retrieval performance, applications in structure-activity modeling of complex biological properties, and comparisons with existing research and commercial methods demonstrate the validity and effectiveness of the approach.

Singh, Rahul

2007-01-01

137

Bond strength to surface enamel for different tooth types  

Microsoft Academic Search

Objectives: Fixed appliance therapy in orthodontics relies on the effective bonding of brackets to surface enamel. Bracket de-bonding during treatment is both inconvenient and costly to both dentist and patient. Factors which control the efficacy of the bond are not fully understood. For example, there has never been a study to determine the efficacy of bonding to different teeth in

R. S Hobson; J. F McCabe; S. D Hogg

2001-01-01

138

Femtosecond laser surface texturing of a nickel-based superalloy  

Microsoft Academic Search

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

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

2008-01-01

139

Division of Icy Bodies into Groups Based on Surface Properties  

Microsoft Academic Search

We propose the division of the icy bodies in the outer Solar System into five groups based on their surface properties. This division can be equivalently made by three definitions involving: size\\/orbit\\/color; measured surface properties; the physical mechanisms that reprocess the surfaces. Our first group is the Small\\/Red bodies (including the red Centaurs, Kuiper Belt Objects, and Scattered Disk Objects)

Bradley E. Schaefer; D. L. Rabinowitz; S. W. Tourtellottte

2008-01-01

140

Acoustic emission-based monitoring of surfaces subjected to friction  

NASA Astrophysics Data System (ADS)

Machine parts often contain components which experience relative motion during service. Relative motion between surfaces causes fatigue crack, wear and eventual surface deterioration. Acoustic emission based machinery condition monitoring is a method which can potentially be used to monitor the state of damage present on surfaces during service. This research deals with changes that occur in the characteristics of acoustic emission signals due to altering surface roughness and texture caused by friction loading. A test fixture was used to simulate friction between surfaces of comparable surface finish and obtain acoustic emission signals generated in the process. The different characteristics of signal waveforms obtained at different instances during the test were examined. It was shown that some features like amplitude and duration of the waveforms are sensitive to surface wear.

Asamene, Kassahun; Sundaresan, Mannur

2012-03-01

141

Surface morphologies of composites based on unsaturated polyester prepolymer  

Microsoft Academic Search

We report the study of surfaces of bulk molding compounds (BMC) based on miscible polymeric thermoset blends (TB)—unsaturated polyester, styrene and low profile additive (LPA)—containing fillers and glass fibers. In contrast to scanning electron microscopy (SEM) that identified a continuous organic layer at the BMC surface, atomic force microscopy (AFM) showed the existence of aggregates linked together to form a

M. Vayer; C. Serré; N. Boyard; C. Sinturel; R. Erre

2002-01-01

142

Volume conduction in an anatomically based surface EMG model  

Microsoft Academic Search

A finite-element model to simulate surface electromyography (EMG) in a realistic human upper arm is presented. The model is used to explore the effect of limb geometry on surface-detected muscle fiber action potentials. The model was based on magnetic resonance images of the subject's upper arm and includes both resistive and capacitive material properties. To validate the model geometry, experimental

Madeleine M. Lowery; Nikolay S. Stoykov; Julius P. A. Dewald; Todd A. Kuiken

2004-01-01

143

Analysis of surface EMG signal based on empirical mode decomposition  

Microsoft Academic Search

In this paper, we propose a combination method based on the empirical mode decomposition and largest Lyapunov exponent technique for the feature extraction of surface EMG signals. Subsequently, the BP neural network is used as a classifier to identify the pattern category of upper limb motions. By the recognition analysis of the surface EMG signals, the data of the single

Min Lei; Guang Meng; Cheng Jiashui

2009-01-01

144

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

2013-01-17

145

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

PubMed

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

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

2013-03-13

146

Remote surface water monitoring radio based telemetry system.  

National Technical Information Service (NTIS)

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 microelectronic...

W. L. Goodwin D. Baxter

1993-01-01

147

NORTH PORTAL SURFACE - BASED COMPRESSED AIR SYSTEM ANALYSIS  

SciTech Connect

The purpose of this analysis is to capture the design requirements and analyze equipment performance relevant to the Surface-Based Compressed Air System (CAS) design at the Yucca Mountain Site Characterization Project (YMP) Exploratory Studies Facility (ESF).

C.L. Mellen

1995-01-18

148

Point-Based Multi-Scale Surface Representation  

Microsoft Academic Search

In this paper we present a new multi-scale surface representation based on point samples. Given an unstructured point cloud as input, our method flrst computes a series of point-based surface approximations at successively higher levels of smoothness, i.e., coarser scales of detail, using geometric low-pass flltering. These point clouds are then encoded relative to each other by ex- pressing each

MARK PAULY; LEIF P. KOBBELT; RWTH Aachen; MARKUS GROSS; ETH Zurich

149

Modeling the Acid–Base Surface Properties of Aquatic Sediments  

Microsoft Academic Search

We propose a model that explains the acid–base surface properties of clastic sediments from two Argentinean reservoir lakes.\\u000a The model uses potentiometric titration data sets and fixed parameters such as the apparent stability constants and reaction\\u000a stoichiometries of acid–base equilibriums involving known mineral phases. The model considers that sediments act as a set\\u000a of independent sorption surfaces, such as organic

L. Borgnino; M. G. Garcia; M. V. del Hidalgo; M. Avena; C. P. De Pauli; M. A. Blesa; P. J. Depetris

2010-01-01

150

Femtosecond laser surface texturing of a nickel-based superalloy  

NASA Astrophysics Data System (ADS)

Femtosecond laser (180 fs, 775 nm, 1 kHz) surface modification of the nickel-based superalloy C263 is investigated. The laser beam was scanned onto areas on the substrate with macroscopic dimensions using different fluences ( F = 0.28-30 J/cm 2), speeds ( ? = 1-10 mm/s) and number of overscans (5-90). The evolution of surface morphology, roughness, ablation depth and volume ablation rate with laser micromachining parameters were determined. The surface morphology is characterized by ripples for low average powers while for high average powers the surface becomes porous.

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

2008-12-01

151

Shock Testing of a Dry Chemical Fire Extinguisher Inclusive a Bracket.  

National Technical Information Service (NTIS)

A dry chemical fire extinguisher and a special bracket, make SAVAL, have been exposed to shock tests. Failure was ascertained with the snap lock belt mechanism. After modification the lock mechanism proved to be working satisfactorily. The shock tests wer...

F. J. VanBragt

1996-01-01

152

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.

2001-07-01

153

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

154

(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

155

Classification of catalytic reactions based on molecular surface science  

SciTech Connect

The surface science studies of catalytic reactions which have been performed to date indicate that there are three types of metal-based catalytic systems: (1) the first encompasses reactions that occur directly on a bare metal surface; (2) the second class includes reactions occurring on an overlayer that is irreversibly bound to the metal surface; and (3) reactions on coadsorbate modified surfaces fall into the third category. These catalysts contain additives that alter the bonding of reactants to the surface, or block specific reaction sites, altering reaction pathways. The following accounts present case histories of surface science studies of catalytic processes representing each of the three categories. We shall discuss ways in which these reaction types may be identified by experiments. Finally, some of the methods that could be employed to build catalysts with desirable properties will be reviewed. 90 refs., 20 figs., 2 tabs.

Somorjai, G.A.

1987-08-01

156

Surface modification for PDMS-based microfluidic devices.  

PubMed

This review focuses on advances reported from April 2009 to May 2011 in PDMS surface modifications for the application in microfluidic devices. PDMS surface modification techniques presented here include improved plasma and graft polymer coating, dynamic surfactant treatment, hydrosilylation-based surface modification and surface modification with nanomaterials such as carbon nanotubes and metal nanoparticles. Recent efforts to generate topographical and chemical patterns on PDMS are also discussed. The described surface modifications not only increase PDMS wettability, inhibit or reduce non-specific adsorption of hydrophobic species onto the surfaces in the act, but also result in the display of desired functional groups useful for molecular separations, biomolecular detection via immunoassays, cell culture and emulsion formation. PMID:22128067

Zhou, Jinwen; Khodakov, Dmitriy A; Ellis, Amanda V; Voelcker, Nicolas H

2011-11-30

157

Measurements of the torque moment in various archwire-bracket-ligation combinations.  

PubMed

The torque moment generated by third-order bends is important for tooth movement. The purpose of this study was to measure the torque moment that can be delivered by various archwire and bracket combinations at the targeted tooth. Stainless steel (SS) upper brackets with 0.018 and 0.022 inch slots, two sizes of nickel-titanium (Ni-Ti) alloy wires, and three sizes of SS wires for each bracket were used. The wire was ligated with elastics or wire. The torque moment delivered by the various archwire-bracket-ligation combinations was measured using a torque gauge. Statistical analysis was undertaken using analysis of variance (multiple comparison tests and post hoc using Tukey's honestly significant difference test. The torque moment increased as the degree of torque and wire size increased. There was no significant difference in torque moment between the SS and Ni-Ti wires at lower or higher than 40 degrees torque. The torque moment with wire ligation was significantly larger than that with elastic ligation with 0.016 × 0.022 and 0.017 × 0.025 inch Ni-Ti wires in the 0.018 inch slot brackets and the 0.017 × 0.025 and 0.019 × 0.025 inch SS and Ni-Ti wires in the 0.022 inch slot brackets. However, there was no significant difference in torque moment between either ligation method when using the full slot size wires. PMID:21571875

Hirai, Miyuki; Nakajima, Akira; Kawai, Nobuhiko; Tanaka, Eiji; Igarashi, Yu; Sakaguchi, Masahito; Sameshima, Glenn T; Shimizu, Noriyoshi

2011-05-13

158

Effect of pine bark extract on bond strength of brackets bonded to bleached human tooth enamel.  

PubMed

Abstract Aim. The purpose was to investigate the effect of pine bark (proanthocyanidin, natural antioxidant) solution on the shear bond strength (SBS) of metal brackets bonded with composite resin to human enamel after bleaching with hydrogen peroxide (HP). Materials and methods. Sixty recently extracted premolars were divided into an experimental group (n = 45), which was bleached with 40% HP, and a control group (n = 15), which was not bleached. The experimental group was further divided into three sub-groups. Specimens in group IB (n = 15) were bonded immediately after bleaching; specimens in group SA (n = 15) were bleached, then treated with 10% sodium ascorbate and then bonded; group PB specimens (n = 15) were bleached, then treated with 5% pine bark solution and bonded. The specimens were debonded with Universal testing machine. The adhesive remnant index was calculated. Results. No significant differences in shear bond strength were noted when the pine bark treated group was compared with the control group and sodium ascorbate group (p > 0.05). Treating the bleached enamel surface with 10% sodium ascorbate or 5% pine bark solution reverses the SBS reduction. Conclusion. So, as a natural antioxidant and less hazardous, clinicians can choose pine bark solution instead of sodium ascorbate. PMID:23638809

Aksakalli, Sertac; Ileri, Zehra; Karacam, Nejla

2013-05-01

159

Contour-Based Surface Reconstruction using MPU Implicit Models  

PubMed Central

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

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

2007-01-01

160

Chemical monitors based on Surface-Enhanced Raman Scattering (SERS)  

SciTech Connect

This paper presents an overview of the development of chemical monitors using the Surface-Enhanced Raman Scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 10[sup 8] when a compound is adsorbed on rough metallic surfaces having submicron protrusions. The focus of our research efforts is on the development of SERS-active sensors and instrumentation capable of field analysis and remote sensing.

Vo-Dinh, T.; Alarie, J.P.; Sutherland, W.S.; Stokes, D.L.; Miller, G.H.

1992-01-01

161

Chemical monitors based on Surface-Enhanced Raman Scattering (SERS)  

SciTech Connect

This paper presents an overview of the development of chemical monitors using the Surface-Enhanced Raman Scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 10{sup 8} when a compound is adsorbed on rough metallic surfaces having submicron protrusions. The focus of our research efforts is on the development of SERS-active sensors and instrumentation capable of field analysis and remote sensing.

Vo-Dinh, T.; Alarie, J.P.; Sutherland, W.S.; Stokes, D.L.; Miller, G.H.

1992-12-31

162

An Ultracompact Surface Plasmon Polariton-Effect-Based Polarization Rotator  

Microsoft Academic Search

A3 - m-long ultrasmall surface plasmon polariton- effect-based transverse-magnetic (TM) mode to transverse-elec- tric (TE) mode polarization rotator was demonstrated both the- oretically and experimentally. Effective polarization rotation with 11-dB polarization extinction ratio (PER) was achieved in fabri- cated devices. The insertion loss at the transition region was about 11 dB. Surface Plasmon polaritons (SPP) are electromagnetic ex- citations propagating

Jing Zhang; Shiyang Zhu; Huijuan Zhang; Shiyi Chen; Guo-Qiang Lo; Dim-Lee Kwong

2011-01-01

163

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

164

A Point-Based Approach to PDE-Based Surface Reconstruction  

Microsoft Academic Search

Variational techniques are a popular approach for recon- structing the surface of an object. In previous work, the surface is repre- sented either implicitly by the use of level sets or explicitly as a triangle mesh. In this paper we describe new formulations and develop fast algo- rithms for surface reconstruction based on partial differential equations (PDEs) derived from variational

Christian Linz; Bastian Goldlücke; Marcus A. Magnor

2006-01-01

165

Nanoparticle-Based Surface Modifications for Microtribology Control and Superhydrophobicity  

NASA Astrophysics Data System (ADS)

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

Hurst, Kendall Matthew

166

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

SciTech Connect

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

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

2012-05-15

167

The effect of clusters on surface based transport modeling  

NASA Astrophysics Data System (ADS)

Clusters are common bedforms that develop as part of the surface structure of gravel and sand channels. Surface grains may re-arrange during a receding flood flow or a sustained low flow such that the larger size fractions group into clusters of two or more grains. These clusters can increase the sheltering effect of the large grains and also the shear stress necessary to mobilize fine sediment sizes. Transport models, both surface and subsurface beds, continue to show scatter when compared to observed transport data. Residuals, the ratio of predicted to measured transport value, remain even when the transport model accounts for the coarser surface sediments through adjustment of the hiding factor. This work examines whether clusters may be responsible for some of the mismatch between predicted and observed transport rates. The Wilcock and Crowe Surface Based Transport Model has been used to predict the transport from beds for which fractional transport data were available. Residuals were then examined against channel bed surface structure. Data from the flume runs used to develop the SBTM were analyzed and clusters were identified from photographs of the channel bed surfaces. Specific residuals were then analyzed for corresponding cluster presence. This analysis provides a first estimate of how the presence of clusters can cause predicted transport rates to deviate from observation.

Curran, Joanna C.; Ockelford, Annie

2013-04-01

168

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

2013-02-25

169

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

170

Thin polymer film based rapid surface acoustic wave humidity sensors  

Microsoft Academic Search

Polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) thin films, deposited on the surface of glass slides, were studied using transmission FTIR spectroscopy upon varying relative humidity (RH) from 2 to 70%. The obtained data revealed fast dynamics of water vapor adsorption–desorption with responses on the order of several seconds. Based on the fast FTIR signal intensity changes versus RH, it

Andrii Buvailo; Yangjun Xing; Jacqueline Hines; Eric Borguet

2011-01-01

171

An Implicit Surface based 2-D \\/ 3-D Medial Extractor  

Microsoft Academic Search

ABSTRACT Medial axis of an ,object is an ,important property ,that is used ,in a ,variety of applications. Although many algorithms are available in 2-D, only a few algorithms are available for 3-D problems. Hence, a medial extractor applicable for both 2-D and 3-D problems, customized for future mesh generation applications, is desired. This thesis presents an implicit surface based

Ragunath Sankaranarayanan

2003-01-01

172

The Effects of Prophylactic Ozone Pretreatment of Enamel on Shear Bond Strength of Orthodontic Brackets Bonded with Total or Self-Etch Adhesive Systems  

PubMed Central

Objectives: The aim of this in vitro study is to determine (1) shear bond strength (SBS) of brackets bonded with self-etch and total-etch adhesive after ozone treatment (2) bond failure interface using a modified Adhesive Remnant Index (ARI). Methods: 52 premolars were randomly assigned into four groups (n=13) and received the following treatments: Group 1: 30 s Ozone (Biozonix, Ozonytron, Vehos Medikal, Ankara, Turkey) application + Transbond Plus Self-Etching Primer (SEP) (3M) + Transbond XT (3M), Group 2: Transbond Plus SEP + Transbond XT, Group 3: 30 s Ozone application + 37% orthophosphoric acid + Transbond XT Primer (3M) + Transbond XT, Group 4: 37% orthophosphoric acid + Transbond XT Primer + Transbond XT. All samples were stored in deionised water at 37°C for 24 hours. Shear debonding test was performed by applying a vertical force to the base of the bracket at a cross-head speed of 1 mm/min. Results: The mean SBS results were Group 1: 10.48 MPa; Group 2: 8.89 MPa; Group 3: 9.41 MPa; Group 4: 9.82 MPa. One-Way Variance Test revealed that the difference between the groups was not statistically significant (P=0.267). Debonded brackets were examined by an optical microscope at X16 magnification to determine the bond failure interface using a modified ARI. The results were (mean) Group 1: 2.38; Group 2: 1.31; Group 3: 3.00; Group 4: 1.92. Multiple comparisons showed that Groups 1 and 2, 2 and 3, 3 and 4 were statistically different (P=0.014, P<.001 and P=0.025). Conclusions: Ozone treatment prior to bracket bonding does not affect the shear bond strength.

Cehreli, Sevi Burcak; Guzey, Asli; Arhun, Neslihan; Cetinsahin, Alev; Unver, Bahtiyar

2010-01-01

173

Tumor bracketing and safety margin estimation using multimodal marker seeds: a proof of concept  

NASA Astrophysics Data System (ADS)

Accurate tumor excision is crucial in the locoregional treatment of cancer, and for this purpose, surgeons often rely on guide wires or radioactive markers for guidance toward the lesion. Further improvement may be obtained by adding optical guidance to currently used methods, in the form of intra-operative fluorescence imaging. To achieve such a multimodal approach, we have generated markers that can be used in a pre-, intra-, and post-operative setting, based on a cocktail of a dual-emissive inorganic dye, lipids, and pertechnetate. Phantom experiments demonstrate that these seeds can be placed accurately around a surrogate tumor using ultrasound. Three-dimensional bracketing provides delineation of the entire lesion. Combined with the multimodal nature, this provides the opportunity to predetermine the resection margins by validating the placement accuracy using multiple imaging modalities (namely, x ray, MRI, SPECT/CT, and ultrasound). The dual-emissive fluorescent properties of the dye provide the unique opportunity to intra-operatively estimate the depth of the seed in the tissue via multispectral imaging: emission green ?max=520 nm<=5 mm penetration versus emission red ?max=660 nm<=12 mm penetration. By using particles with different colors, the original geographic orientation of the excised tissue can be determined.

Buckle, Tessa; Chin, Patrick T. K.; van den Berg, Nynke S.; Loo, Claudette E.; Koops, Wim; Gilhuijs, Kenneth G. A.; van Leeuwen, Fijs W. B.

2010-09-01

174

Transfection of cells attached to selected cell based biosensor surfaces.  

PubMed

Mammalian cell attachment studies were conducted on a variety of common microchip surfaces for potential use in cell based biosensors. COS-7 cell attachment to Au, Pt or ITO, per unit area was greater than to SiO(2) surfaces. The number of cells that would attach was essentially maximized 3 h after cell seeding. HL-1 cells attached more readily to surfaces precoated with fibronectin, but by 3 h equivalent number of cells had attached independent of fibronectin precoating. Inclusion of serum in media during the initial period of attachment decreased the number of COS-7 cells attached to SiO(2) surfaces, but no dependence on serum was seen for ITO surfaces. The number of cells attached per unit area varied with the composition of the surface. However, no differences were observed in the percentage of cells transfected with a green fluorescent protein gene, or in the level of reporter gene expression over the population of transfected cells on ITO, SiO(2), Pt, Ag, or Au surfaces. Similar FACS analysis of transfected Hep G2 cells revealed lower levels of both transfection efficiency and levels of GFP fluorescence. Hep G2 cells plated on Ag did not remain attached for analysis, but there were no significant differences between tissue culture plastic and the other biosensor surfaces in the percentage of cells transfected. This suggests that, in general, cells will attach to the various conducting and nonconducting biosensor surfaces studied and will provide comparable data in reporter gene expression assays. PMID:17261315

O'Connell, Daniel J; Molinar, Arlette J; Tavares, Andre Luiz Pasqua; Mathine, David L; Runyan, Raymond B; Bahl, Joseph J

2007-01-11

175

Partial Surface Integration Based on Variational Implicit Functions and Surfaces for 3D Model Building  

Microsoft Academic Search

Most three-dimensional acquisition systems generate several partial reconstructions that have to be registered and integrated for building a complete 3D model. In this paper, we propose a volumetric shape integration method, consisting of weighted signed distance functions represented as variational implicit functions (VIF) or surfaces (VIS). Texture integration is solved similarly by using three weighted color junctions also based on

P. Claes; Dirk Vandermeulen; Luc J. Van Gool; Paul Suetens

2005-01-01

176

Surface chemical modification of poly(dimethylsiloxane)-based biomimetic materials: oil-repellent surfaces.  

PubMed

The oil-repellent performance of a poly(dimethylsiloxane)-based biomimetic replica (PDMS-replica) was tuned by modifying its surface chemical composition. PDMS-replica possessing a complementary combination of hierarchical roughness and mixed -CF(3) and -SiCH(3) terminal functionality was prepared in the presence of a surface-modifying agent, using nanocasting based on soft lithography. PDMS-replica showed superhydrophobicity and enhanced oil repellency, theta(oil) approximately 86 degrees . PDMS-replica was further modified with silica nanoparticles followed by chemical vapor deposition of (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane. The -CF(3) terminal, silica-modified PDMS-replica (i.e., PDMS-replica(silica/CF(3))) showed both superhydrophobic and high oil-repellent properties (advancing theta(oil) approximately 120 degrees ). During the process of each chemical transformation, the surface pattern present on PDMS-replica was preserved and monitored using scanning electron microscopy. Surface chemical compositions of PDMS-replica and PDMS-replica(silica/CF(3)) were determined using X-ray photoelectron spectroscopy. Understanding the extent of adhesion on a biomimetic replica possessing different surface chemical compositions and roughness would provide fundamental information for various applications. PMID:20356137

Ghosh, Nilmoni; Bajoria, Arpan; Vaidya, Ashish Anant

2009-11-01

177

[In-vitro research on the thermal debonding of ceramic brackets].  

PubMed

The mechanical debonding of ceramic brackets using special instruments involves the use of a degree of force that is damaging to the enamel. For this reason, the authors have developed the Ceramic Debonding Unit for the thermal debonding of ceramic brackets. The unit reduces the force necessary for debonding, without overheating the tooth. The present article explains the principle of the unit. The influence on the temperature increase in the pulpa of the mechanical torque applied during debonding, and the time taken for debonding was investigated in extracted teeth (lower central incisors). Tests on ceramic brackets made by various manufacturers showed that safe debonding is possible if the debonding time does not exceed 3 seconds at a torque of 100 Nnm. The temperature increase in the pulpa will not exceed 5 degrees C when the Ceramic Debonding Unit is used under these conditions, so that harmful overheating of healthy teeth does not occur. PMID:1778523

Bäzner, B; Ettwein, K H; Röhlcke, F; Sernetz, F

1991-12-01

178

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.

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

2013-01-01

179

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

180

Frictional resistances in stainless steel bracket-wire combinations with effects of vertical defections  

Microsoft Academic Search

This research evaluated the effects of different bracket-wire combinations and second-order deflections on kinetic friction. Thirteen different brackets, six with 0.018 × 0.025 inch slots and seven with 0.022 × 0.028-inch slots were evaluated with six different sizes and shapes of stainless steel orthodontic wire, i.e., 0.016, 0.016 × 0.022, 0.017 × 0.025, 0.018, 0.018 × 0.025 and 0.019 ×

Randall H. Ogata; Ram S. Nanda; Manville G. Duncanson; Pramod K. Sinha; G. Fräns Currier

1996-01-01

181

A new multicomponent surface tension correlation based on scaling theory  

SciTech Connect

This paper presents a multicomponent surface tension correlation based on scaling theory. In addition to particular exponents employed, the correlation contains two new features: A corresponding-states equation is derived for a correlation coefficient, commonly referred to as a parachor. As a result, the hydrocarbon pseudocomponent parachors can be calculated through this equation, once their pseudocritical properties are estimated. An approach is proposed to calculate the parachors of mixtures. In contrast to the conventional approach, which calculates the mixture parachor via molar mixing of component parachors, this approach first obtains the pseudocritical properties of the mixture and then employs the corresponding-states equation to calculate the mixture parachor. For various reservoir-fluid related pure components, the corresponding-states equation predicts parachor values to within 1% of those listed in the literature. The surface-tension correlation developed was tested against 45 sets of measured binary surface tension data and four sets of multicomponent CO/sub 2/-reservoir oil surface tension data. Other existing surface tension correlations, i.e. Weinaug-Katz's and Stegmeier-Hough's correlations, are also tested and compared. For the 45 sets of binary data, the average deviation of the new surface tension correlation is 3.71%, which is about 50% smaller than the deviations of the other two correlation cited. In addition, for the CO/sub 2/-reservoir fluid data, the average deviation is about 7.3%, which is also a significant improvement over the existing correlations. It is worth noting that the surface tension correlation developed does not involve any adjusted parameter and it is also completely compatible with existing compositional numerical simulators.

Lee, S.T.; Chien, M.C.H.

1984-04-01

182

Surface recrystallization of a single crystal nickel-base superalloy  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

183

Beam tilted base station antenna with electromagnetic gradient surface  

Microsoft Academic Search

A base station antenna for WCDMA band (1.920-2.170 GHz) application utilizing an electromagnetic gradient surface (EGS) is proposed. The EGS is applied as a reflector of 4×2 dipole array to tilt the beam with electrically without phase shifters on low-profile structure. Therefore the beam can be tilted with lower complexity, smaller size, and cheaper cost compared to conventional mechanical or

Ji Hwan Yoon; Jihwan Ahn; Kihun Chang; Young Joong Yoon

2010-01-01

184

Fingerprint Image Segmentation Based on Quadric Surface Model  

Microsoft Academic Search

\\u000a It is essential to segment fingerprint image from background effectively, which could improve image processing speed and fingerprint\\u000a recognition accuracy. This paper proposes a novel fingerprint segmentation method at pixel level based on quadric surface\\u000a model. Three parameters, Coherence, Mean and Variance of each pixel are extracted and spatial distribution model of fingerprint pixels is acquired and analyzed. Our study

Yilong Yin; Yanrong Wang; Xiukun Yang

2005-01-01

185

Real-time path-based surface detail  

Microsoft Academic Search

We present a GPU algorithm to render path-based 3D surface detail in real-time. Our method models these features using a vector representation that is efficiently stored in two textures. First texture is used to specify the position of the features, while the second texture contains their paths, profiles and material information. A fragment shader is then proposed to evaluate this

Carles Bosch; Gustavo Patow

2010-01-01

186

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

187

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

188

Normal faciolingual inclinations of tooth crowns compared with treatment groups of standard and pretorqued brackets  

Microsoft Academic Search

Faciolingual inclinations of tooth crowns were measured on plaster casts of normal occlusions and posttreatment orthodontic models of treated cases. Normal anatomic occlusion, standard edgewise and Roth bracket groups of 10 subjects were examined for a change in torque values. On study models, crown inclinations of right and left central teeth to second molar in the upper and lower dental

Tülin U?ur; Filiz Yukay

1997-01-01

189

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.

190

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.

191

Process Qualification and Testing of LENS Deposited Ay1E125 D-Bottle Brackets.  

National Technical Information Service (NTIS)

The LENS Qualification team had the goal of performing a process qualification for the Laser Engineered Net Shaping(LENS) process. Process Qualification requires that a part be selected for process demonstration. The AY1E0125 D-Bottle Bracket from the W80...

D. D. Gill J. E. Smugeresky C. J. Atwood M. D. Jew S. Scheffel

2006-01-01

192

Stochastic Response Surface Based Simulation Of Ground Water Modeling  

SciTech Connect

Estimation of Uncertainty associated with groundwater modeling is an important aspect in nuclear industries. Traditional methods for propagating the uncertainty, such as Monte Carlo require prohibitive number of model simulation for complex model. Stochastic response surface method which is more computationally efficient is based on polynomial expansion of model input and output in terms of well behaved random variables that are identically and independently distributed. The model output at collocation point is evaluated to know the unknown coefficients in the series expansion of output. The uncertainty in concentration profile and degree of uncertainty is evaluated for model. The present paper describes the novel approach of stochastic response surface technique to estimate the uncertainty in the groundwater modeling.

Ranade, A. K.; Pandey, M.; Datta, D. [Computational Radiation Physics Section, Health Physics Division, Bhabha Atomic Research Centre Mumbai-85 (India)

2010-10-26

193

Wireless surface acoustic wave and MEMS-based microsensors  

NASA Astrophysics Data System (ADS)

The integration of SAW (Surface Acoustic Wave), MEMS and required microelectronics and conformal antennas to realize programmable microsensors suitable for many engineering and biomedical applications will be presented in this talk. This unique combination of technologies results in novel conformal sensors that can be remotely sensed by a wireless communication system with the advantage of no power requirements at the sensor site (passive sensor). The required features in many of these applications are high precision, wide dynamic range and wide frequency range. MEMS-SAW based devices presented possess typical advantages of MEMS sensors including the additional benefits of robustness, excellent sensitivity, surface conformability and durability. After a brief overview of SAW sensors and MEMS, the paper is focused on the design and fabrication of MEMS devices for a few engineering applications such as accelerometer and gyroscopes for automobile, inertial navigation sensors and tire pressure sensor.

Varadan, Vijay K.; Varadan, Vasundara V.

2001-04-01

194

Applying tensor-based morphometry to parametric surfaces can improve MRI-based disease diagnosis.  

PubMed

Many methods have been proposed for computer-assisted diagnostic classification. Full tensor information and machine learning with 3D maps derived from brain images may help detect subtle differences or classify subjects into different groups. Here we develop a new approach to apply tensor-based morphometry to parametric surface models for diagnostic classification. We use this approach to identify cortical surface features for use in diagnostic classifiers. First, with holomorphic 1-forms, we compute an efficient and accurate conformal mapping from a multiply connected mesh to the so-called slit domain. Next, the surface parameterization approach provides a natural way to register anatomical surfaces across subjects using a constrained harmonic map. To analyze anatomical differences, we then analyze the full Riemannian surface metric tensors, which retain multivariate information on local surface geometry. As the number of voxels in a 3D image is large, sparse learning is a promising method to select a subset of imaging features and to improve classification accuracy. Focusing on vertices with greatest effect sizes, we train a diagnostic classifier using the surface features selected by an L1-norm based sparse learning method. Stability selection is applied to validate the selected feature sets. We tested the algorithm on MRI-derived cortical surfaces from 42 subjects with genetically confirmed Williams syndrome and 40 age-matched controls, multivariate statistics on the local tensors gave greater effect sizes for detecting group differences relative to other TBM-based statistics including analysis of the Jacobian determinant and the largest eigenvalue of the surface metric. Our method also gave reasonable classification results relative to the Jacobian determinant, the pair of eigenvalues of the Jacobian matrix and volume features. This analysis pipeline may boost the power of morphometry studies, and may assist with image-based classification. PMID:23435208

Wang, Yalin; Yuan, Lei; Shi, Jie; Greve, Alexander; Ye, Jieping; Toga, Arthur W; Reiss, Allan L; Thompson, Paul M

2013-02-20

195

Surface acid-base behaviors of Chinese loess.  

PubMed

Acid-base titration was applied to investigate the surface acid-base properties of a Chinese loess sample at different ionic strengths. The acidimetric supernatant was regarded as the system blank of titration to correct the influence of particle dissolution on the estimation of proton consumption. The titration behavior of the system blank could be described by the hydrolysis of Al3+ and Si(OH)4 in aqueous solution as well as the production of hydroxyaluminosilicates. The formation of Al-Si species on homogeneous surface sites by hydrous aluminum and silicic acid, released from solid substrate during the acidic titration, was considered in the model description of the back-titration procedure. A surface reaction model was suggested as follows: >SOH<-->SO(-)+H+, pK(a)(int)=3.48-3.98;>SOH+Al(3+)+H4SiO4<-->SOAl(OSi(OH)3(+)+2H+, pK(SC)=3.48-4.04. Two simple surface complexation models accounted for the interfacial structure, i.e., the constant capacitance model (CCM) and the diffuse layer model (DLM), and gave a satisfactory description of the experimental data. Considering the effect of ionic strength on the electrostatic profile at the solid-aqueous interface, the DLM was appropriate at the low concentrations (0.01 and 0.005 mol/L) of background electrolyte (NaNO3 in this study), while the CCM was preferable in the case of high ionic strength (0.1 mol/L). PMID:16290808

Chu, Zhaosheng; Liu, Wenxin; Tang, Hongxiao; Qian, Tianwei; Li, Shushen; Li, Zhentang; Wu, Guibin

2002-08-15

196

Wide steering angle microscanner based on curved surface  

NASA Astrophysics Data System (ADS)

Intensive industrial and academic research is oriented towards the design and fabrication of optical beam steering systems based on MEMS technology. In most of these systems, the scanning is achieved by rotating a flat micromirror around a central axis in which the main challenge is achieving a wide mirror rotation angle. In this work, a novel method of optical beam scanning based on reflection from a curved surface is presented. The scanning occurs when the optical axis of the curved surface is displaced with respect to the optical axis of the incident beam. To overcome the possible deformation of the spot with the scanning angle, the curved surface is designed with a specific aspherical profile. Moreover, the scanning exhibits a more linearized scanning angle-displacement relation than the conventional spherical profile. The presented scanner is fabricated using DRIE technology on an SOI wafer. The curved surface (reflector) is metalized and attached to a comb-drive actuator fabricated in the same lithography step. A single-mode fiber, behaving as a Gaussian beam source, is positioned on the substrate facing the mirror. The reflected optical beam angle and spotsize in the far field is recorded versus the relative shift between the fiber and the curved mirror. The spot size is plotted versus the scanning angle and a scanning spot size uniformity of about +/-10% is obtained for optical deflection angles up to 100 degrees. As the optical beam is propagating parallel to the wafer substrate, a completely integrated laser scanner can be achieved with filters and actuators self-aligned on the same chip that allows low cost and mass production of this important product.

Sabry, Yasser; Khalil, Diaa; Saadany, Bassam; Bourouina, Tarik

2013-03-01

197

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.

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

2012-01-01

198

Localized surface plasmon resonance based fiber optic sensor with nanoparticles  

NASA Astrophysics Data System (ADS)

A localized surface plasmon resonance (LSPR) based fiber optic sensor with a nanoparticle layer coated on the core of the optical fiber has been presented and theoretically analyzed. Nanoparticles of four materials: ITO, Au, Ag and Cu have been considered for the study. The complete analysis of sensitivity of the LSPR based fiber optic sensor with each nanoparticle layer individually for various values of thickness and particle size has been done numerically in order to use these four materials in plasmonic sensing applications. The sensitivity of LSPR based fiber optic sensor increases with the increase in the thickness of nanoparticles layer for all four materials. Also, for a fixed value of thickness of nanoparticles layer, the sensitivity of LSPR based fiber optic sensor further increases as the particle size of nanoparticles increases (up to 20 nm). The optimized values of thickness and particle size of nanoparticles layers for all four materials individually are revealed to be 60 nm and 20 nm respectively. With sensitivity of 6240 nm/RIU, the 60 nm thick ITO nanoparticles layer (with 20 nm particle size) based LSPR sensor has been shown to have better performance than other three material's naoparticles based LSPR sensors.

Rani, Mahima; Sharma, Navneet K.; Sajal, Vivek

2013-04-01

199

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

200

Anodic surface oxidation mechanisms of PAN-based and pitch-based carbon fibres  

Microsoft Academic Search

In order to clarify the differences in the anodic surface oxidation mechanisms of PAN-based and pitch-based carbon fibres, the fibres were oxidized in an electrolyte and characterized using the coulostatic method, X-ray photoelectron spectroscopy, laser Raman spectroscopy, and X-ray diffraction. The interfacial bonding strength to an epoxy resin was evaluated based on the interlaminar shear strength (ILSS). The results showed

A. Fukunaga; S. Ueda; M. Nagumo

1999-01-01

201

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.

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

2011-01-01

202

Cell Kinase Activity Assay Based on Surface Enhanced Raman Spectroscopy  

PubMed Central

Kinases control many important aspects of cell behavior, such as signal transduction, growth/differentiation, and tumorogenesis. Current methods for assessing kinase activity often require specific antibodies, and/or radioactive labeling. Here we demonstrated a novel detection method to assess kinase activity based on surface enhanced Raman spectroscopy (SERS). Raman signal was obtained after amplification by silver nanoparticles. The sensitivity of this method was comparable to fluorescence measurement of peptide concentration. When purified kinase enzyme was used, the detection limit was comparable to conventional radio-labeling method. We further demonstrated the feasibility to measure kinase activity in crude cell lysate. We suggested this SERS-based kinase activity assay could be a new tool for biomedical research and application.

Yue, Zhicao; Zhuang, Fengfeng; Kumar, Rajar; Wong, Ieong; Cronin, Stephen B; Liu, Yi-Hsin

2009-01-01

203

Measurement of Orthodontic Bracket Tie Wing Elastic and Plastic Deformation by Arch Wire Torque Expression Utilizing an Optical Image Correlation Technique  

PubMed Central

Orthodontic lingual root movement (torque) is an important aspect of treatment biomechanics and is typically achieved by torsion of a rectangular wire within the orthodontic bracket slot which introduces a force couple. The magnitude of the force moment achieved by wire torsion may be influenced by deformation of the orthodontic bracket. A device utilizing an optical image correlation technique has been developed to accurately quantify bracket slot dimensional changes during application of wire torsion. Simultaneous torque moment magnitude, degrees of wire twist, and bracket slot dimension data can be gathered. Bracket tie wing elastic deformation when loaded was demonstrated and plastic deformation was also observed with a single rotation of the wire.

Lacoursiere, Ryan A.; Nobes, David S.; Homeniuk, Darren L. N.; Carey, Jason P.; Badawi, Hisham H.; Major, Paul W.

2010-01-01

204

Automatic Feature-based Surface Mapping for Brain Cortices  

Microsoft Academic Search

We present a method that maps a complex surface geometry to an equally complicated, similar surface. One main objective of our effort is to develop technology for automatically transferring surface annotations from an atlas brain to a subject brain. While macroscopic regions of brain surfaces often correspond, the detailed surface geometry of corresponding areas can vary greatly. We have developed

Fabien Vivodtzev; David F. Wiley; Lars Linsen; James Jones; Nina Amenta; Bernd Hamann; Kenneth I. Joy

205

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 6.6Mcps (Mega counts per second) down to 0.436Mcps at the lowest threshold (0.5 photon-equivalent) and from 1.2kcps down to 0.02cps 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

206

Automated Landmark Identification for Human Cortical Surface-Based Registration  

PubMed Central

Volume-based registration (VBR) is the predominant method used in human neuroimaging to compensate for individual variability. However, surface-based registration (SBR) techniques have an inherent advantage over VBR because they respect the topology of the convoluted cortical sheet. There is evidence that existing SBR methods indeed confer a registration advantage over affine VBR. Landmark-SBR constrains registration using explicit landmarks to represent corresponding geographical locations on individual and atlas surfaces. The need for manual landmark identification has been an impediment to the widespread adoption of Landmark-SBR. To circumvent this obstacle, we have implemented and evaluated an automated landmark identification (ALI) algorithm for registration to the human PALS-B12 atlas. We compared ALI performance with that from two trained human raters and one expert anatomical rater (ENR). We employed both quantitative and qualitative quality assurance metrics, including a biologically meaningful analysis of hemispheric asymmetry. ALI performed well across all quality assurance tests, indicating that it yields robust and largely accurate results that require only modest manual correction (<10 min per subject). ALI largely circumvents human error and bias and enables high throughput analysis of large neuroimaging datasets for inter-subject registration to an atlas.

Anticevic, Alan; Repovs, Grega; Dierker, Donna; Harwell, John; Coalson, Tim; Barch, Deanna M.; Van Essen, David C.

2012-01-01

207

Surface relief gratings in azobenzene supramolecular systems based on polyimides  

NASA Astrophysics Data System (ADS)

The paper describes formation of new supramolecular azopolymers based on hydrogen bonds as perspective materials for laser induced surface relief gratings (SRGs) and for polarization gratings. Supramolecular films were built on the basis of hydrogen bonds between the functional groups of polymer and azobenzene derivatives, that is 4-[4-(3-hydroxypropyloxy)phenylazo]-pyridine and 4-[4-(6-hydroxyhexyloxy)phenylazo]pyridine. Polymers with imide rings, i.e., poly(esterimide)s and poly(etherimide)s, with phenolic hydroxyl or carboxylic groups were applied as matrixes for polymer-dye supramolecular systems. They revealed glass transition temperatures (Tg) in the range of 170-260 °C, whereas supramolecular systems exhibited lower Tg (88-187 °C). The polymers were easily soluble in aprotic polar solvents and exhibited remarkable good film forming properties. Moreover, new chromophore 4-[4-(3-hydroxypropyloxy)phenylazo]pyridine was synthesized and characterized. The light induced SRGs formation and simultaneous formation of the polarization gratings were explored in prepared polymer-chromophore assembles films using a holographic grating recording technique. First time to the best of our knowledge SRGs were formed in hydrogen-bonded supramolecular systems based on polyimides. The highest SRG amplitude and thus the highest diffraction efficiency were obtained in poly(esterimide)s with the hydroxyl functional group. Additionally, the thermal stability of the photoinduced surface gratings and polarization gratings were tested revealing in the case of the SRGs partial stability and almost complete erasure of the polarization gratings.

Schab-Balcerzak, Ewa; Sobolewska, Anna; Stumpe, Joachim; Hamryszak, Lukasz; Bujak, Piotr

2012-12-01

208

Polymer-based chips for surface plasmon resonance sensors  

NASA Astrophysics Data System (ADS)

This paper presents a design and low-cost techniques for polymer-based chips for surface plasmon resonance (SPR) sensors. To obtain a polymer chip with a prism, microchannels and a chamber at microscale dimensions, replication techniques in polymers with controlled refractive index have been developed. Photoresist, polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA) and epoxy resin were used. Silicon dioxide/silicon-based molds have been obtained by anisotropic etching of silicon, and glass prisms were used as masters for replication. The photoresist molds were obtained by optical lithography and were used to obtain the microchannels and the chamber. A liquid prepolymer (PDMS, Sylgard 184) with curing agent at a ratio of 10:1 was used, and a special technique was developed in order to fabricate the components of the structure at the same time. For the deposition and direct patterning of the metallic layers onto the polymer surface, different methods were experimented with, including sputtering. The materials and techniques used to achieve SPR sensors are presented, and the possibilities and limitations of the technology are discussed.

Obreja, Paula; Cristea, Dana; Kusko, Mihai; Dinescu, Adrian

2008-06-01

209

Comparative performance of AVHRR-based multichannel sea surface temperatures  

NASA Astrophysics Data System (ADS)

A brief outline of the basic concepts of cloud filtering and atmospheric attenuation corrections used in the Multi-channel Sea Surface Temperature (MCSST) method is given. The operational MCSST procedures and products are described in detail. The comparative performance of AVHRR-based MCSST'S is discussed via the use of the results of the JPL Satellite-Derived Sea Surface Temperature workshops. For the four data periods there is surprisingly good correspondence in the sign and location of the major monthly mean SST anomaly features derived from MCSST's and those from a screened set of ship-based SST's. With the partial exception of the one data period severely affected in some areas by volcanic aerosol from El Chichon eruptions, global statistical measures of the MCSST anomalies relative to the the ship data are as follows: biases, 0.3-0.4°C (MCSST lower than ship); standard deviations, 0.5-0.6°C; and cross-correlations, +0.3 to +0.7. A refined technique in use with NOAA 9 data in 1985 has yielded consistent biases and rms differences near -0.1°C and 0.5°C, respectively.

McClain, E. Paul; Pichel, William G.; Walton, Charles C.

1985-11-01

210

Surface modification of nickel based alloys for improved oxidation resistance  

SciTech Connect

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

Jablonski, Paul D.; Alman, David E.

2005-02-01

211

Combined Satellite- and Surface-Based Observations of Clouds.  

NASA Astrophysics Data System (ADS)

A new method for combining satellite and surface-based cloud observations into a self-consistent three-dimensional field is presented. This method derives the probabilities of the cloud states, which are most consistent with all of the observations and assumptions concerning the nature and relative uncertainties of the observations. It is applied to a three-layer atmosphere using monthly satellite- and surface-based cloud observations. The reconstructions of the observed fields usually lead to modifications of the surface-observed low cloud amount of less than 0.008 fractional cloud cover. Over the ocean the satellite-view low cloud amounts are usually decreased by between 0.06 and 0.12 for most of the middle latitudes and southeastern tropical Pacific. Over land the adjustments in the satellite low cloud amounts are generally smaller. The method leads to increases in satellite high cover of between 0.03 and 0.09 over most regions, and increases in middle cloud cover of up to around 0.03 over the subtropical oceans. Comparisons between derived total cloud cover and that calculated with the commonly used random and mixed overlap assumptions suggest that the mixed assumption generally better fits the results. On the whole there is overall fairly good agreement between the percent low cloud relative to total cloud cover in the reconstructed observations and a global climate model, but the model has a far larger percentage of high clouds nearly everywhere, especially in the tropical convective regions and over the Indian subcontinent.

Weare, Bryan C.

1999-03-01

212

On Discriminating between Geometric Strategies of Surface-Based Orientation  

PubMed Central

Recently, a debate has manifested in the spatial learning literature regarding the shape parameters by which mobile organisms orient with respect to the environment. On one hand are principal-axis-based strategies which suggest that organisms extract the major and minor principal axes of space which pass through the centroid and approximate length and width of the entire space, respectively. On the other hand are medial-axis-based strategies which suggest that organisms extract a trunk-and-branch system similar to the skeleton of a shape. With competing explanations comes the necessity to devise experiments capable of producing divergent predictions. Here, we suggest that a recent experiment (i.e., Sturz and Bodily, 2011a) may be able to shed empirical light on this debate. Specifically, we suggest that a reevaluation of the design reveals that the enclosures used for training and testing appear to produce divergent predictions between these strategies. We suggest that the obtained data appear inconsistent with a medial-axis-based strategy and that the study may provide an example of the types of designs capable of discriminating between these geometric strategies of surface-based orientation. Such an approach appears critical to fundamental issues regarding the nature of space and spatial perception.

Sturz, Bradley R.; Bodily, Kent D.

2012-01-01

213

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

214

Dynamic PDE-based surface design using geometric and physical constraints  

Microsoft Academic Search

PDE surfaces, which are defined as solutions of partial differential equations (PDEs), offer many modeling advantages in surface blending, free-form surface modeling, and specifying surfaces aesthetic or functional requirements. Despite the earlier advances of PDE surfaces, previous PDE-based techniques exhibit certain difficulties such as lack of interactive sculpting capabilities and restrained topological structure of modeled objects. This paper presents an

Haixia Du; Hong Qin

2005-01-01

215

Sensitivity of microarray based immunoassays using surface-attached hydrogels.  

PubMed

A promising pathway to improve on the sensitivity of protein microarrays is to immobilize the capture antibodies in a three dimensional hydrogel matrix. We describe a simple method based on printing of an aqueous protein solution containing a photosensitive polymer and the capture antibody onto a plastic chip surface. During short UV-exposure photocrosslinking occurs, which leads to formation of a hydrogel, which is simultaneously bound to the substrate surface. In the same reaction the antibody becomes covalently attached to the forming hydrogel. As the capture antibodies are immobilized in the three-dimensional hydrogel microstructures, high fluorescence intensities can be obtained. The chip system is designed such, that non-specific protein adsorption is strongly prevented. Thus, the background fluorescence is strongly reduced and very high signal-to-background ratios are obtained (SBR>6 for c(BSA)=1 pM; SBR>100 for c(BSA)>100 pM). The kinetics of antigen binding to the arrayed antibodies can be used to determine the concentration of a specific protein (for example the tumor marker ?2-microglobulin) in solution for a broad range of analyte concentrations. By varying size and composition of the protein-filled hydrogel microstructures as well as adjusting the extent of labeling it is possible to easily adapt the surface concentration of the probe molecules such that the fluorescence signal intensity is tuned to the prevalence of the protein in the analyte. As a consequence, the signal tuning allows to analyze solutions, which contain both proteins with high (here: upper mg mL(-1) range) and with very low concentrations (here: lower ?g mL(-1) range). This way quantitative analysis with an exceptionally large dynamic range can be performed. PMID:23684467

Moschallski, Meike; Evers, Andreas; Brandstetter, Thomas; Rühe, Jürgen

2013-04-16

216

CAD-based CMM inspection of sculptured surfaces  

Microsoft Academic Search

Sculptured surfaces are used in several applications. The manufacture of sculptured surfaces is carried out using numerically-controlled machines, and automatically-generated tool paths. This process is affected by several error sources, which result in geometric deviation between the machined surface, and the design intent. Coordinate measuring machines, CMMs, are used to assess the quality of the machined surfaces. ^ A new

Diaa F ElKott

2007-01-01

217

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

218

Detection of explosives based on surface-enhanced Raman spectroscopy.  

PubMed

In this study we present a device based on surface-enhanced Raman scattering (SERS) for the detection of airborne explosives. The explosives are resublimated on a cooled nanostructured gold substrate. The explosives trinitrotoluene (TNT) and triacetone triperoxide (TATP) are used. The SERS spectrum of the explosives is analyzed. Thus, TNT is deposited from an acetonitrile solution on the gold substrate. In the case of TATP, first the bulk TATP Raman spectrum was recorded and compared with the SERS spectrum, generated by deposition out of the gas phase. The frequencies of the SERS spectrum are hardly shifted compared to the spectrum of bulk TATP. The influence of the nanostructured gold substrate temperature on the signals of TATP was studied. A decrease in temperature up to 200 K increased the intensities of the TATP bands in the SERS spectrum; below 200 K, the TATP fingerprint disappeared. PMID:20697437

Wackerbarth, Hainer; Salb, Christian; Gundrum, Lars; Niederkrüger, Matthias; Christou, Konstantin; Beushausen, Volker; Viöl, Wolfgang

2010-08-10

219

Recent advances in DNA-based directed assembly on surfaces  

NASA Astrophysics Data System (ADS)

In the last decade, ``small'' and ``integrated'' have been keywords in the field of device fabrication as the desire to exploit nanoscale phenomena and make electronic, photonic and magnetic arrays has grown. In an effort to improve resolution and control costs, much work has been dedicated to developing alternatives to conventional microfabrication technology. For this purpose, biomolecular assembly and DNA nanotechnology in particular are appealing owing to their inherent size and capacity for molecular recognition. Herein, we review recent achievements in DNA-based directed assembly on substrates. These include novel methods for patterning and depositing nanomaterials on DNA-modified surfaces as well as using synthetic DNA nanostructures such as DNA tiles and origami as templates to direct the assembly of nanoscale components. Particular attention is paid to integrating self-assembly with top-down lithography, and some possible directions for future work are discussed.

Hung, Albert M.; Noh, Hyunwoo; Cha, Jennifer N.

2010-12-01

220

[Effect of thermoelectrochemical recycling treatment on direct orthodontic brackets: morphological and dimensional S.E.M. analysis].  

PubMed

The AA, analyze the effects of recycling treatment of orthodontic stainless direct brackets. The ESMA method has been utilized, by BIG JANE E3762. A morphological and dimensional analysis has been done, before and after recycling, by SEM. PMID:3079107

Laino, A; Sangiovanni, R; Manfredi, C; Michelotti, A; Valletta, R

1988-12-01

221

Nanostructure-Based Localized Surface Plasmon Resonance Biosensors  

Microsoft Academic Search

\\u000a This chapter reviews the characteristics of localized surface plasmon resonance (LSPR), the excitation of which is mediated\\u000a by nanostructures, and its applications to biosensing. The LSPR is explored in three regimes in terms of creation and coupling\\u000a of localized surface plasmons (LSPs): LSPs created in surface-relief patterns coupled to propagating surface plasmons (SPs),\\u000a LSPs in surface-relief patterns coupled to particle

Donghyun Kim

2010-01-01

222

Surface classification and detection of latent fingerprints: Novel approach based on surface texture parameters  

Microsoft Academic Search

The classification of surfaces has importance in the field of latent fingerprint detection in crime scene forensics because the adaptive preprocessing depends on the surface texture. This paper shows a novel approach to classify various materials with the help of surface texture parameters. Three-dimensional surface data of potential crime scene is produced using a chromatic white light sensor. The results

Stefan Gruhn; Claus Vielhauer

2011-01-01

223

Does a reduction of polymerization time and bonding steps affect the bond strength of brackets?  

PubMed

High bond strengths are required in order to avoid bracket failure during treatment while brackets should be removable. In addition, chair time should be kept at a minimum. Therefore, the aim of this study was to investigate any differences in bracket's bond strength to enamel by reducing the polymerization time and the steps of bonding procedure. Five hundred teeth were randomly allocated into 20 groups. The groups were established considering the investigated curing units (quartz-tungsten-halogen (QTH) and light-emitting diode (LED), each with two different polymerization times) and the used bonding agents (Clearfil SE Bond, Transbond Plus, Ideal1, iBond, and Transbond XT Primer following acid etching). The brackets were debonded using a shear-peel load and used to calculate the bond strength. The location of adhesive failure was registered by using the modified adhesive remnant index (ARI). The influence of the parameters curing unit, curing time, and bonding agent as well as their interaction products on bond strength showed that the bonding agent influenced the bond strength most followed by curing time. The parameter curing unit as well as all the generated interaction products of it showed a lower impact. Regarding the ARI, the bonding agent exhibited also the highest influence. Using a LED resulted in comparable bond strengths as the QTH curing device also at shorter exposure times. Additionally, the two-component self-etching primers showed similar bond strengths compared to the acid-etching method. Chair time can be reduced by using two-component self-etching primers and LED without decrease of bond strength. PMID:21448637

Lamper, Timea; Steinhäuser-Andresen, Stefanie; Huth, Karin C; Ilie, Nicoleta; Paschos, Ekaterini

2011-03-30

224

An evaluation and comparison of orthodontic bracket bond strengths achieved with self-etching primer  

Microsoft Academic Search

The bonding of orthodontic brackets to enamel is a multistep process. To simplify bonding and decrease chair time, Transbond Plus Self-Etching Primer (3M Unitek, Monrovia, Calif) has been introduced; the primer combines the etching, rinsing, and priming steps. This in vitro study evaluated the shear bond strengths and interoperator variability of self-etching primer, as compared with conventional phosphoric acid etching

Helen S. I Grubisa; Giseon Heo; Don Raboud; Kenneth E Glover; Paul W Major

2004-01-01

225

Quantifying modern biomes based on surface pollen data in China  

NASA Astrophysics Data System (ADS)

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

Chen, Yu; Ni, Jian; Herzschuh, Ulrike

2010-12-01

226

Frictional Forces of Conventional and Improved Superelastic NiTi-Alloy Orthodontic Archwires in Stainless Steel and Plastic Brackets  

Microsoft Academic Search

\\u000a This study evaluated the static and kinetic frictional forces produced between different combination of orthodontic archwires\\u000a and brackets. Three types of archwires were examined: (1) stainless steel, (2) conventional NiTi alloy, and (3) improved superelastic\\u000a NiTi alloy. Two types of brackets were tested: (1) stainless steel and (2) plastic. Both static and kinetic frictional forces\\u000a were measured on a customdesigned

Jui-Ting Hsu; Li-Chun Wu; Yin-Yu Chang; Tzu-Ning Weng; Heng-Li Huang; Chein-Hung Yu

227

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

PubMed

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

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

1999-08-01

228

Effect of applying a sustained force during bonding orthodontic brackets on the adhesive layer and on shear bond strength.  

PubMed

The objective of this research was to investigate the effect of applying a sustained seating force during bonding on the adhesive layer and on shear bond strength (SBS) of orthodontic brackets. Forty human premolars divided into two groups were included in the study. Stainless steel brackets were bonded to the premolars with Transbond XT light cure adhesive and Transbond Plus Self Etch Primer (SEP). The brackets in both groups were subjected to an initial seating force of 300 g for 3 seconds, sufficient to position the bracket. The seating force was maintained throughout the 40 seconds of light curing in group 2. SBS was tested 24 hours after bracket bonding with a shear blade using an Instron testing unit at a crosshead speed of 2 mm/minute. A Student's t-test was used to compare the bond strength of the two groups and a chi-square test to compare the frequencies of the adhesive remnant index (ARI) scores. The mean SBS was significantly different between the two groups (P=0.025). The bond strength was higher (mean 8.15±0.89 MPa) in group 2 compared with group 1 (mean 7.39±1.14 MPa). There was no significant difference (P=0.440) in the ARI scores between the two groups. Applying a sustained seating force during orthodontic bracket bonding improves bond strength but does not change the distribution of the ARI scores. PMID:21030470

Montasser, Mona A

2010-10-28

229

Surface plasmon resonance based fiber optic glucose biosensor  

NASA Astrophysics Data System (ADS)

A surface plasmon resonance (SPR) based fiber optic biosensor has been fabricated and characterized for the detection of blood glucose. Optical fiber sensor was fabricated by first coating a 50 nm thick gold film on the bare core of optical fiber and then immobilizing glucose oxidase (GOx) over it. Aqueous glucose solutions of different concentrations were prepared. To mimic the blood glucose levels, the concentration of glucose solutions were kept equal to that in human blood. The refractive indices of these sample solutions were equal to that of water up to third decimal place. SPR spectra for the sensor were recorded for these glucose solutions. When the glucose comes in contact to glucose oxidase, chemical reactions take place and as a result, the refractive index of the immobilized GOx film changes, giving rise to a shift in the resonance wavelength. Unlike electrochemical sensors, the present sensor is based on optics and can be miniaturized because of optical fiber. The present study provides a different approach for blood glucose sensing and may be commercialized after optimization of certain parameters.

Srivastava, Sachin K.; Verma, Roli; Gupta, Banshi D.

2012-01-01

230

Monocular Template-based Reconstruction of Inextensible Surfaces  

Microsoft Academic Search

We present a monocular 3D reconstruction algorithm for inextensible deformable surfaces. It uses point correspondences between\\u000a a single image of the deformed surface taken by a camera with known intrinsic parameters and a template. The main assumption\\u000a we make is that the surface shape as seen in the template is known. Since the surface is inextensible, its deformations are\\u000a isometric

Mathieu Perriollat; Richard Hartley; Adrien Bartoli

231

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

232

Classification of Surface EMG Signal Based on Energy Spectra Change  

Microsoft Academic Search

In this paper, we introduced a novel and simple methods of extracting the general features of two surface EMG signal patterns: forearm supination (FS) and forearm pronation (FP) surface EMG signals. The surface EMG signal was divided into two segments appropriately at the preparation stage and the action stages. Relative wavelet packet energy (RWPE, symbolized by pnp and pna respectively

Xiao Hu; Ping Yu; Qun Yu; Waixi Liu; Jian Qin

2008-01-01

233

Formation and properties of silicon elastomer-based responsive surfaces  

Microsoft Academic Search

Responsive surfaces facilitate prompt response to an external stimulus, such as electrical, chemical, or mechanical; the ultimate responsive surface is one that instantaneously responds to its environment with a measurable property change. We report on forming responsive surfaces from model silicon elastomer (SE) networks containing vinyl functionalities, which can be chemically or physically modified to attach various functional groups. Rapid

Julie Crowe; Dwight Schwark

2005-01-01

234

Superhydrophobic surfaces with nanofibers or nanorods based on thiophene derivatives  

NASA Astrophysics Data System (ADS)

Fabricating superhydrophobic surfaces via self-assembly of organic conjugated small molecules is realized by spray-drying the thiophene derivates organic solutions. Formation of microsized pores and arrayed nanofibers or nanorods on the surfaces is responsible for the superhydrophobicity of the coatings. This technique can be applied for fabrication of large area superhydrophobic surfaces with conjugated molecules on different substrates.

Jia, Zhixin; Liu, Mingxian; Liu, Fang; Luo, Yuanfang; Jia, Demin; Guo, Baochun

2010-01-01

235

Effects of AFM-based nanomachining process on aluminum surface  

Microsoft Academic Search

Surface analysis of nanomachined material is studied by atomic force microscopy (AFM). To understand the influence of different machined conditions on surface characterization, several nanomachining experiments are performed. Multiple furrows are conducted on a silicon substrate coated with aluminum films under the four different applied loads, including 4, 8, 12, 16?N. Results indicate that the average surface roughness and the

Te-Hua Fang; Win-Jin Chang

2003-01-01

236

Surface-based registration accuracy of CT-based image-guided spine surgery.  

PubMed

Registration is a critical and important process in maintaining the accuracy of CT-based image-guided surgery. The aim of this study was to evaluate the effects of the area of intraoperative data sampling and number of sampling points on the accuracy of surface-based registration in a CT-based spinal-navigation system, using an optical three-dimensional localizer. A cadaveric dry-bone phantom of the lumbar spine was used. To evaluate registration accuracy, three alumina ceramic balls were attached to the anterior and lateral aspects of the vertebral body. CT images of the phantom were obtained (1-mm slice thickness, at1-mm intervals) using a helical CT scanner. Twenty surface points were digitized from five zones defined on the basis of anatomical classification on the posterior aspects of the target vertebra. A total of 20 sets of sampling data were obtained. Evaluation of registration accuracy accounted for positional and rotational errors. Of the five zones, the area that was the largest and easiest to expose surgically and to digitize surface points was the lamina. The lamina was defined as standard zone. On this zone, the effect of the number of sampling points on the positional and rotational accuracy of registration was evaluated. And the effects of the additional area selected for intraoperative data sampling on the registration accuracy were evaluated. Using 20 surface points on the posterior side of the lamina, positional error was 0.96 mm +/- 0.24 mm root-mean-square (RMS) and rotational error was 0.91 degrees +/- 0.38 degrees RMS. The use of 20 surface points on the lamina usually allows surgeons to carry out sufficiently accurate registration to conduct computer-aided spine surgery. In the case of severe spondylosis, however, it might be difficult to digitize the surface points from the lamina, due to a hypertrophic facet joint or the deformity of the lamina and noisy sampling data. In such cases, registration accuracy can be improved by combining use of the 20 surface points on the lamina with surface points on other zones, such as on the both sides of the spinous process. PMID:15526221

Tamura, Yuichi; Sugano, Nobuhiko; Sasama, Toshihiko; Sato, Yoshinobu; Tamura, Shinichi; Yonenobu, Kazuo; Yoshikawa, Hideki; Ochi, Takahiro

2004-11-04

237

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

PubMed Central

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

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

2001-01-01

238

Roughness-Adaptive 3-D Watermarking Based on Masking Effect of Surface Roughness  

Microsoft Academic Search

We present a method to improve watermark robustness by exploiting the masking effect of surface roughness on watermark visibility. Our idea is to adapt watermark strength to local surface roughness based on the knowledge that human eyes are less sensitive to changes on a rougher surface patch than those on a smoother surface. In order to quantify human sensitivity to

Kwangtaek Kim; Mauro Barni; Hong Z. Tan

2010-01-01

239

Superhydrophobic/superhydrophilic surfaces from a carbon nanotube based composite coating  

NASA Astrophysics Data System (ADS)

A facile method for forming a MWNT-based composite coating with behavior of the superhydrophilic/superhydrophobic transition is demonstrated. The change of the surface microstructure and the surface chemical composition arising from increasing temperatures determines the surface wettability of the resulting composite coating. The coating surface shows the superhydrophobic property at 150, 200, and 360°, and displays superhydrophilic performance at 300°C.

Men, Xue-Hu; Zhang, Zhao-Zhu; Yang, Jin; Wang, Kun; Jiang, Wei

2010-02-01

240

Terahertz wave filter based on frequency-selective surface structure  

NASA Astrophysics Data System (ADS)

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

Sun, Chao; Li, Jiu-sheng

2011-11-01

241

Surface acoustic wave sensors of delay lines based on MEMS.  

PubMed

A high frequency Surface Acoustic Wave (SAW) filter which is the key point of the SAW sensor is made by MEMS technology. The SAW filter used for sensors needs to have the factors of high frequency, low loss and high quality factor. In order to satisfy the performance of the factors, the SAW delay lines of Electrode Wave Control Single Phase Unidirectional Transducer (EWC/SPUDT) are used in the filter. This transducer can be considered as the networks of connection of some units of IDTs and the loss of device can be effectively reduced. Based on the Coupling of Modes (COM) theory and equivalent circuit modal, the mixed matrix (P matrix) of the transducers can be deduced, and further, the response of the delay lines can be obtained. According to the calculated results, a mask layout is made. Then the SAW delay line is completed and found to agree with the theoretical simulation. Its center frequency is 503 MHz and insertion loss is low enough for use of sensors. PMID:21137910

Haofeng, Li; Rui, Jia; Weilong, Li; Chen, Chen; Xinyu, Liu

2010-11-01

242

New Manipulator Based on Surface Acoustic Wave Streaming  

NASA Astrophysics Data System (ADS)

We report a new micromanipulator based on the surface acoustic wave (SAW) streaming. When a small solid object is loaded onto a water droplet placed on a SAW substrate and the SAW is excited, the object can be moved easily and smoothly with the droplet in the SAW propagation direction. Small steel balls of 0.5 to 4.0 mm in diameter were examined as manipulated samples to be loaded onto a droplet. The experimental results are compared with those of the direct drive method without preloading, by which an object is moved towards an operating interdigital transducer (IDT) in the direction opposite to the SAW propagation direction. It was observed, that the driving efficiency of the present method was sixty times larger than that of the direct drive method. Moreover, a teflon sheet, which is difficult to move by the direct drive method, can be moved with ease by the present method. We conclude that the present method has a high potential for practical use as a micromanipulator.

Sano, Akihiko; Matsui, Yoshikazu; Shiokawa, Showko

1998-05-01

243

pH sensors based on hydrogenated diamond surfaces  

Microsoft Academic Search

We report on the operation of ungated surface conductive diamond devices in electrolytic solutions. The effect of electrolyte pH on the channel conductivity is studied in detail. It is shown that fully hydrogen terminated diamond surfaces are not pH sensitive. However, a pronounced pH sensitivity arises after a mild surface oxidation by ozone. We propose that charged ions from the

Jose A. Garrido; Stefan Kuch; Martin Stutzmann; Oliver A. Williams; R. B. Jackmann

2005-01-01

244

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

245

Quantitation of surface coverage of oligonucleotides bound to chip surfaces: a fluorescence-based approach using alkaline phosphatase digestion.  

PubMed

Silanized chip surfaces provide a reliable substrate for immobilization of oligonucleotides. The ability for rapid and sensitive detection of oligonucleotide surface coverage on these chips is crucial for their wide and effective applications in biotechnology. In this paper, two different silanization procedures were used to covalently bind fluorescent-labeled single-stranded DNA onto silicon dioxide or nitride chip surfaces. Effects of surface functionalization techniques for different surfaces, and immobilization conditions, including buffers and solution ionic strength, on surface probe coverage were investigated, quantifying the endpoint probe density by fluorescent measurement upon digestion with alkaline phosphatase (ALP). Digestion of surface-immobilized oligonuleotides with ALP released the fluorophore-tagged probe fragments back into the solution. The detection of DNA was accomplished by laser-induced fluorescence detection of the solution containing those cleaved fragments. The probe surface density on gold thin film, determined by ALP-digestion, was found to coincide well with that measured using the conventional alkanethiol-based fluorescence-displacement technique for the same system. The developed method has important implications for evaluating the performance of different oligonucleotide immobilization strategies. Also, it has the potential to serve as a sample-thrifty, time saving, and therefore routine tool to realize more realistic, practical quantification of the surface coverage of oligonucleotides immobilized on any solid surfaces. PMID:18651076

Pal, Sukdeb; Kim, Min Jung; Song, Joon Myong

2008-06-06

246

TE Surface Wave Resonances on High-Impedance Surface Based Antennas: Analysis and Modeling  

Microsoft Academic Search

Low-profile antennas comprising a horizontal dipole above a high-impedance surface are analyzed. The emphasis of this paper is on the additional resonances of the radiating struc- ture caused by surface waves propagating on the high-impedance surface. It is shown that such resonances can be favorably used for broadening the bandwidth of the antenna. The phenomenon is thoroughly modeled by exploiting

Filippo Costa; Olli Luukkonen; Constantin R. Simovski; Agostino Monorchio; Sergei A. Tretyakov; Peter M. de Maagt

2011-01-01

247

Simultaneous Estimation of Sea Surface Temperature and Precipitable Water Based on MOS-1/VTIR Data.  

National Technical Information Service (NTIS)

In the retrieval of the precipitable water and the sea surface temperature simultaneously from the data of satellite observation based on the linearized radiative transfer equation, selection of the optimum initial guess values of sea surface temperature,...

S. Takasaki M. Matsumoto K. Tsuchiya

1990-01-01

248

An organic pollution sensor based on surface photovoltage  

Microsoft Academic Search

A surface photovoltage (SPV) device, which is sensitive to surface pH, was applied to the fabrication of an organic pollution sensor. Trichosporon cutaneum, designated for use as a biochemical oxygen demand (BOD) sensor by the Japanese Industrial Standard, was employed as the immobilized biocatalyst. A flow cell of the system consists of an SPV device and a microbial membrane immobilized

Yuji Murakami; Takayuki Kikuchi; Akira Yamamura; Toshifumi Sakaguchi; Kenji Yokoyama; Yoshitaka Ito; Masataka Takiue; Hidekazu Uchida; Teruaki Katsube; Eiichi Tamiya

1998-01-01

249

pH sensors based on hydrogenated diamond surfaces  

NASA Astrophysics Data System (ADS)

We report on the operation of ungated surface conductive diamond devices in electrolytic solutions. The effect of electrolyte pH on the channel conductivity is studied in detail. It is shown that fully hydrogen terminated diamond surfaces are not pH sensitive. However, a pronounced pH sensitivity arises after a mild surface oxidation by ozone. We propose that charged ions from the electrolyte adsorbed on the oxidized surface regions induce a lateral electrostatic modulation of the conductive hole accumulation layer on the surface. In contrast, charged ions are not expected to be adsorbed on the hydrogen terminated surface, either due to the screening induced by a dense layer of strongly adsorbed counter-ions or by the absence of the proper reactive surface groups. Therefore, the modulation of the surface conductivity is generated by the oxidized regions, which are described as microscopic chemical in-plane gates. The pH sensitivity mechanism proposed here differs qualitatively from the one used to explain the behavior of conventional ion sensitive field effect transistors, resulting in a pH sensitivity higher than the Nernstian limit.

Garrido, Jose A.; Härtl, Andreas; Kuch, Stefan; Stutzmann, Martin; Williams, Oliver A.; Jackmann, R. B.

2005-02-01

250

Vision-Based Drivable Surface Detection in Autonomous Ground Vehicles  

Microsoft Academic Search

One of the primary tasks for most autonomous ground vehicles is road following. For safe maneuvering the vehicle needs to correctly identify the drivable surface. Our work is focused on the use of simple video cameras as the sensor devices. We describe a new machine learning approach to drivable surface detection that automatically combines a set of rectangular features and

Ying Guo; Vadim Gerasimov; Geoff Poulton

2006-01-01

251

Rough Surface Scattering Based on the Specular Point Theory  

Microsoft Academic Search

The average number of specular points per unit area for a two-dimensionally rough surface is derived in terms of the surface statistics. Expressions for the average of the product of the principal radii of curvature of the specular point are also obtained. These quantities are then substituted into the average scattering cross section per unit area derived from the stationary-phase

DONALD E. BARRICK

1968-01-01

252

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

NASA Astrophysics Data System (ADS)

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

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

2009-07-01

253

Superhydrophobic graphene-based materials: surface construction and functional applications.  

PubMed

Many naturally occurring surfaces have superhydrophobicity that fulfils their functional demands, which has inspired considerable interest to develop similar artificial superhydrophobic surfaces with a variety of functionalities. Graphene is an ideal candidate for functional superhydrophobic surfaces due to its exceptional physicochemical properties. The recent advances in this emerging field are summarized, including the wetting behavior of water on graphene and the formation of crumpling/nanoparticle/foam-induced hierarchical structures, with emphasis on fundamental understanding for related processes. The potential applications in energy, environmental remediation, and thermal management are also discussed. PMID:24089354

Chen, Zhongxin; Dong, Lei; Yang, Dong; Lu, Hongbin

2013-09-02

254

Influence of surface properties of resin-based composites on in vitro Streptococcus mutans biofilm development.  

PubMed

The aim of this in vitro study was to evaluate the influence of physicochemical surface properties of resin-based composites on Streptococcus mutans biofilm formation. Specimens were prepared from each of four resin-based composites by polymerization against Mylar strips. Half of the number of specimens received no further surface treatment, whereas the other half were subjected to a polishing treatment. Surface roughness (SR) and topography were assessed using profilometry and atomic force microscopy. Surface free-energy (SFE) was determined, and the chemical surface composition was analysed by X-ray photoelectron spectroscopy (XPS). S. mutans biofilms were formed on the surface of the resin-based composite specimens for either 48 or 96 h using an artificial mouth system (AMS). Polishing caused a significant decrease in SFE, and XPS analysis indicated an increase of surface silicon and a decrease of surface carbon. Only for Grandio was a significant increase in SR identified after polishing, which was probably related to the higher concentration of filler particles on its surface. Significantly less S. mutans biofilm formation was observed on polished resin-based composites than on unpolished resin-based composites. These results indicate that the proportions of resin matrix and filler particles on the surface of resin-based composites strongly influence S. mutans biofilm formation in vitro, suggesting that minimization of resin matrix exposure might be useful to reduce biofilm formation on the surface of resin-based composites. PMID:22985005

Ionescu, Andrei; Wutscher, Elisabeth; Brambilla, Eugenio; Schneider-Feyrer, Sibylle; Giessibl, Franz J; Hahnel, Sebastian

2012-08-06

255

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

256

Surface Plasmon Resonance Spectroscopy-Based Process Sensors.  

National Technical Information Service (NTIS)

The Analytical Development Section (ADS) of the Savannah River Technology Center (SRTC) developed a novel, monolithic surface plasmon resonance (SPR) probe for process monitoring as part of the Defense Programs Plant Directed Research and Development Prog...

S. McWhorter B. B. Anderson K. Zeigler

2003-01-01

257

Surface Reactions Studied by Synchrotron Based Photoelectron Spectroscopy.  

National Technical Information Service (NTIS)

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

J. Hrbek

1999-01-01

258

Molecule-Sized Gates Based on Surface-Confined Dendrimers.  

National Technical Information Service (NTIS)

In this report we demonstrate for the first time that surface confined-dendrimers embedded within self-assembled monolayers (SAMs) of alkylthiols can act as ion gates of molecular dimension. These composite organic thin films are conceptually, structurall...

M. Zhao H. Tokuhisa R. M. Crooks

1997-01-01

259

Display method study of extruded surface based on ray tracing  

Microsoft Academic Search

This paper describes the ray tracing algorithm in detail, giving the mathematical principles of intersection of the light and extruded surface objects and the method to generate normal of intersection,and building a mathematical model for computer processing and displaying tensile objects. Finally,we map out realistic images of objects in the OpenGL environment and ultimately realized the display of extruded surface

Gao Guohong; Shan Yongqiang; Fu Junhui; Lv Jinna

2010-01-01

260

Rover-Based Surface and Subsurface Modeling for Planetary Exploration  

Microsoft Academic Search

\\u000a We develop and test a technique for the creation of coupled surface and subsurface models. Images from a stereo camera are\\u000a used to estimate the motion of a rover that is collecting ground penetrating radar (GPR) data. The motion estimate and raw\\u000a sensor data are used to build two novel data products: (1) A three-dimensional, photorealistic surface model coupled with

Paul Furgale; Tim Barfoot; Nadeem Ghafoor

261

Optimizing particle collection for enhanced surface-based biosensors  

Microsoft Academic Search

In this article, electrode structures that combine dielectrophoretic effects with electrohydrodynamic fluid flow to concentrate particles on active sensor surfaces were presented. To optimize the collection effect on a surface, a novel electrode configuration called zipper electrodes has been developed. The local enrichment effect of these electrodes is such that particles at local concentration of 5×103 spores\\/mL can be collected

KAI F. HOETTGES; MICHAEL P. HUGHES; ANDREW COTTON; N. A. E. Hopkins; M. B. McDonnell

2003-01-01

262

Three-dimensional modeling of surface plasmon resonance based biosensor  

NASA Astrophysics Data System (ADS)

The surface plasmon resonance (SPR) is one of the most attractive and precise enabling mechanism for sensors in biomedical applications. Conventional biological experiments are performed manually, time consuming intervention and expensive interconnection techniques. This paper simulates three dimensional behavior of magnetic and electric fields of light coupled into a SPR mode propagating along a thin gold layer surrounded by symmetric dielectric layers. This study successfully illustrates the three-dimensional simulation of surface plasmon wave using finite element method in COMSOL Multiphysics suit.

Jahanshahi, Peyman; Parvizi, Amin; Mahamd Adikan, Faisal Rafiq

2013-06-01

263

Surface effect vehicles and surface effect: General studies. Citations from the NTIS data base  

NASA Astrophysics Data System (ADS)

The bibliography contains 180 citations in which the design of surface effect vehicles, their utilization, and their aerodynamic characteristics are investigated. Vehicles or ships in marine environments are not included.

Habercom, G. E., Jr.

1980-08-01

264

Operational Satellite-based Surface Oil Analyses (Invited)  

NASA Astrophysics Data System (ADS)

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

Streett, D.; Warren, C.

2010-12-01

265

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

266

Ship-based measurements of sea surface topography  

NASA Astrophysics Data System (ADS)

By equipping the research vessel Kilo Moana with a geodetic GPS receiver and a radar water level gauge, and using a kinematic GPS processing package, accurate 1 Hz estimates of the sea surface height were obtained. Geodetic positioning of ocean-platforms using only the GPS system cannot account for changes in the draft of the platform. This is especially problematic for ships, where changes in the load, speed and/or ocean density can change the ship's draft by 10s of centimeters. By installing a radar gauge this noise source can be removed from the estimates of the sea surface height. We envision that this technology could routinely provide high resolution information on the geoid, or the variation of the sea surface height, including sea-state, from an existing reference geoid.

Foster, J. H.; Carter, G. S.; Merrifield, M. A.

2009-06-01

267

Laser-based nanoengineering of surface topographies for biomedical applications  

NASA Astrophysics Data System (ADS)

In this study femtosecond laser systems were used for nanoengineering of special surface topographies in silicon and titanium. Besides the control of feature sizes, we demonstrated that laser structuring caused changes in material wettability due to a reduced surface contact area. These laser-engineered topographies were tested for their capability to control cellular behavior of human fibroblasts, SH-SY5Y neuroblastoma cells, and MG-63 osteoblasts. We found that fibroblasts reduced cell growth on the structures, while the other cell types proliferated at the same rate. These findings make laser-surface structuring very attractive for biomedical applications. Finally, to explain the results the correlation between topography and the biophysics of cellular adhesion, which is the key step of selective cell control, is discussed.

Schlie, Sabrina; Fadeeva, Elena; Koroleva, Anastasia; Ovsianikov, Aleksandr; Koch, Jürgen; Ngezahayo, Anaclet; Chichkov, Boris. N.

2011-04-01

268

Magnesium-based composites with improved in vitro surface biocompatibility  

PubMed Central

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

Huan, Zhiguang; Duszczyk, Jurek

2010-01-01

269

Cyclodextrin-based surface acoustic wave chemical microsensors  

SciTech Connect

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

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

1996-07-01

270

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

271

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

Microsoft Academic Search

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

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

2005-01-01

272

Downward propagating internal waves generated at the base of the surface layer of a stratified fluid  

Microsoft Academic Search

Downward propagating internal waves are observed in laboratory experiments. They appear to be generated by the 'obstacle effect' beneath a turbulent surface layer in a surface stress driven stratified flow experiment in a rectangular cavity. The obstacles are the perturbations at the base of the surface layer and the shear is created by a combination of an internal seiche and

Craig Stevens; Jorg Imberger

1994-01-01

273

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

Microsoft Academic Search

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

Mitsuru Sekioka; Kozo Yuhara

1974-01-01

274

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

Microsoft Academic Search

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

Bing Xu; Xiaoshu Wang; Yun Lu

2006-01-01

275

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

276

Poisson-bracket approach to the dynamics of bent-core molecules.  

PubMed

We generalize our previous work on the phase stability and hydrodynamic of polar liquid crystals possessing local uniaxial C infinity v symmetry to biaxial systems exhibiting local C2v symmetry. Our work is motivated by the recently discovered examples of thermotropic biaxial nematic liquid crystals comprising bent-core mesogens, whose molecular structure is characterized by a non-polar-body axis (n) as well as a polar axis (p) along the bisector of the bent mesogenic core which is coincident with a large, transverse dipole moment. The free energy for this system differs from that of biaxial nematic liquid crystals in that it contains terms violating the p-->-p symmetry. We show that, in spite of a general splay instability associated with these parity-odd terms, a uniform polarized biaxial state can be stable in a range of parameters. We then derive the hydrodynamic equations of the system, via the Poisson-bracket formalism, in the polarized state and comment on the structure of the corresponding linear hydrodynamic modes. In our Poisson-bracket derivation, we also compute the flow-alignment parameters along the three symmetry axes in terms of microscopic parameters associated with the molecular geometry of the constituent biaxial mesogens. PMID:17677474

Kung, William; Marchetti, M Cristina

2007-07-20

277

Poisson-bracket approach to the dynamics of bent-core molecules  

NASA Astrophysics Data System (ADS)

We generalize our previous work on the phase stability and hydrodynamic of polar liquid crystals possessing local uniaxial C?v symmetry to biaxial systems exhibiting local C2v symmetry. Our work is motivated by the recently discovered examples of thermotropic biaxial nematic liquid crystals comprising bent-core mesogens, whose molecular structure is characterized by a non-polar-body axis (n) as well as a polar axis (p) along the bisector of the bent mesogenic core which is coincident with a large, transverse dipole moment. The free energy for this system differs from that of biaxial nematic liquid crystals in that it contains terms violating the p?-p symmetry. We show that, in spite of a general splay instability associated with these parity-odd terms, a uniform polarized biaxial state can be stable in a range of parameters. We then derive the hydrodynamic equations of the system, via the Poisson-bracket formalism, in the polarized state and comment on the structure of the corresponding linear hydrodynamic modes. In our Poisson-bracket derivation, we also compute the flow-alignment parameters along the three symmetry axes in terms of microscopic parameters associated with the molecular geometry of the constituent biaxial mesogens.

Kung, William; Marchetti, M. Cristina

2007-07-01

278

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

279

Imaging analysis of nanolithography based on surface-plasmon polariton  

Microsoft Academic Search

The continuing size reduction of integrated circuits to nano dimensions requires the development of advanced lithographic techniques. In order to obtain the desired feature sizes, it has become increasingly complex and high-cost to use the established methods of optical projection lithography at short optical wavelengths. Surface-plasmon polariton interference lithography (SPPIL) can provide a feasible way to achieve or approach the

Wei Xiong; Xiaowei Guo; Jinglei Du; Xi Hou; Chunlei Du; Jun Yao

2006-01-01

280

Automated differentiation of urban surfaces based on airborne hyperspectral imagery  

Microsoft Academic Search

The urban environment is characterized by an intense use of the available space, where the preservation of open green spaces is of special ecological importance. Because of dynamic urban development and high mapping costs, municipal authorities are interested in effective methods for mapping urban surface cover types that can be used for evaluating ecological conditions in urban structures and supporting

Sigrid Roessner; Karl Segl; Uta Heiden; Hermann Kaufmann

2001-01-01

281

A laser-based measurement system for transparent surface forming  

NASA Astrophysics Data System (ADS)

Because the forming process of transparent surface is entirely artificial, it is difficult to meet the requirements of real-time and high precision. In this paper, the laser monitoring system solution can solve this problem. This system consists of three parts, a laser, a CCD camera, and a computer. The laser beam is injected to the transparent surface, and received by the CCD camera. The image is processed by the computer in real-time. By the changes of laser spot during the forming process, a solution is proposed to calculate the difference between the two spot images, which determines the change of height. The experimental results show that when the transparent surface grows 1mm, the effective axial length changes 30 pixels. After multiple measurements, we obtain the relationship curve between the height of the transparent surface and effective axial length. According to the curve, we calculate the measurement error is 2.725%. The processing speed of computer is also measured. It can process 10 pictures per second. The algorithm reflects superiority in both accuracy and processing speed.

Li, Mingyan; Sang, Xinzhu; Sun, Yang; Yan, Binbin; Yu, Chongxiu

2012-11-01

282

Surface-treated mica based on muscovite for anticorrosive coatings  

Microsoft Academic Search

The paper deals with using lamellar pigments for anticorrosive barrier coatings. By depositing a ferric oxide layer on a muscovite particle a pigment is obtained, which being applied to coatings improves the mechanical properties thereof, resistance to UV radiation and acts as an anticorrosion barrier. The optimum concentration of lamellar surface-treated muscovite in the coatings amounts to 20 vol. %.

Andréa Kalendová

2002-01-01

283

Tuning Performance of Metamaterial-Based Frequency Selective Surfaces  

Microsoft Academic Search

A bandpass, miniaturized-element frequency selective surface with relatively high out-band rejection was recently reported whose unit cell dimensions are smaller than lambda 0 \\/10. The new FSS is made up of a metallic, square loop array and a metallic grid on either side of a thin dielectric substrate. Further analysis on this structure reveals that, a very wide frequency tuning

Farhad Bayatpur; Kamal Sarabandi

2009-01-01

284

Modeling the acid–base surface chemistry of montmorillonite  

Microsoft Academic Search

Proton uptake on montmorillonite edge surfaces can control pore water pH, solute adsorption, dissolution kinetics and clay colloid behavior in engineered clay barriers and natural weathering environments. Knowledge of proton uptake reactions, however, is currently limited by strong discrepancies between reported montmorillonite titration data sets and by conflicting estimates of edge structure, reactivity and electrostatics. In the present study, we

Ian C. Bourg; Garrison Sposito; Alain C. M. Bourg

2007-01-01

285

Toward physically based estimation of surface irrigation infiltration  

Technology Transfer Automated Retrieval System (TEKTRAN)

Irrigation practitioners continue to use empirical infiltration equations. Theoretical infiltration equations are currently not capable of capturing surface irrigation infiltration behaviour, particularly at short times. An example is shown where the Green-Ampt equation can be adjusted to match fiel...

286

Shore-based Photogrammetry of Surface Oil Films  

Microsoft Academic Search

Naturally occurring oil slicks are commonly visible in coastal waters. These slicks are suitable proxies for fuel oil spills. We took advantage of these naturally occurring slicks by developing a low-cost system to measure these features and monitor their movement. The use of low-cost digital cameras and a mapping program produces georectified animations of surface features, which can then be

J. Whitefield; N. Record; A. J. Pershing

2010-01-01

287

Surface and Volume Discretization of Functionally Based Heterogeneous Objects  

Microsoft Academic Search

The presented approach to discretization of functionally defined heterogeneous objects is oriented towards applications associated with numerical simulation procedures, for example, finite element analysis (FEA). Such applications impose specific constraints upon the resulting surface and volume meshes in terms of their topology and metric characteristics, exactness of the geometry approximation, and conformity with initial attributes. The function representation of the

Elena Kartasheva; Valery Adzhiev; Alexander A. Pasko; Oleg Fryazinov; Vladimir Gasilov

2003-01-01

288

Paper based Flexible and Conformal SERS Substrate for Rapid Trace Detection on Real-world Surfaces  

Microsoft Academic Search

One of the important but often overlooked considerations in the design of surface enhanced Raman scattering (SERS) substrates for trace detection is the efficiency of sample collection. Conventional designs based on rigid substrates such as silicon, alumina, and glass resist conformal contact with the surface under investigation, making the sample collection inefficient. We demonstrate a novel SERS substrate based on

Srikanth Singamaneni; Chang Lee; Limei Tian

2011-01-01

289

Surface-Charge-Based Micro-Models--A Solid Foundation for Learning about Direct Current Circuits  

ERIC Educational Resources Information Center

|This study explores how the use of a surface-charge-based instructional approach affects introductory university level students' understanding of direct current (dc) circuits. The introduced teaching intervention includes electrostatics, surface-charge-based micro-models that explain the existence of an electric field inside the current-carrying…

Hirvonen, P. E.

2007-01-01

290

Surface plasmon-based infrared spectroscopy for cell biosensing.  

PubMed

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. PMID:23224170

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

2012-08-01

291

Optical multilayers for LED-based surface plasmon resonance sensors.  

PubMed

We address a structure for surface plasmon resonance (SPR) sensing supporting a symmetric bound surface plasmon, which results in a SPR feature narrower by a factor of 2 compared with that for the conventional configuration. We demonstrate that it enables a low-cost and low-power-consumption LED to be used as a polychromatic light source, which leads to a decrease in the sensor cost and an increase in the sensor miniaturization potential. Further, we show that these advancements are not at the expense of sensor performance in terms of its sensitivity and resolution. We show that the sensor can be designed to have similar sensitivity and even better resolution compared with those for a conventional configuration. PMID:16724133

Slavík, Radan; Homola, Jirí

2006-06-01

292

Subwavelength patterning based on a surface plasmon resonant cavity  

NASA Astrophysics Data System (ADS)

With the development of Super Large Scale Integration (SLSI) and integrated optics, high-resolution photolithography has become more and more important. Traditional photolithography is limited by the optical diffraction of the system. Recent discovery of extraordinary behaviors of the surface plasmon polaritons suggests a novel method of photolithography beyond the diffraction limit. In this paper, we report on a novel subwavelength nanolithography technique using a surface plasmonic resonant cavity formed by two metallic layers separated by a photoresist layer with two incident beams illuminating from two sides. Finite-difference time-domain (FDTD) simulations show that a two-dimensional (2D) dot array pattern with a period of 70 nm can be obtained using an exposure radiation of 436nm wavelength. It is also found that the period of the 2D dot array is tunable which can be implemented by varying the cavity length.

Chen, Genhua; Wang, Chinhua; Xiao, Wei; Xu, Fuyang; Lou, Yiming; Cao, Bing; Zhang, Guiju

2012-10-01

293

Surface-surface interference detection for five-axis machine tool path planning based on triangle subdivision  

Microsoft Academic Search

Interference detection between surfaces of the part and the cutting tool is important in 5-axis tool path planning process. The purpose is to ensure the tool in an interference-free posture. There are many ways to detect interference; in this article, the subdivision method is applied. In this research, a simple but high efficiency algorithm based on triangle subdivision has been

Feng Lin; Xiaolei Deng

2010-01-01

294

Surface Plasmon Resonance Based Sensitive Immunosensor for Benzaldehyde Detection  

NASA Astrophysics Data System (ADS)

Fragrant compounds used to add flavor to beverages remain in the manufacturing line after the beverage manufacturing process. Line cleanliness before the next manufacturing cycle is difficult to estimate by sensory analysis, making excessive washing necessary. A new measurement system to determine line cleanliness is desired. In this study, we attempted to detect benzaldehyde (Bz) using an anti-Bz monoclonal antibody (Bz-Ab) and a surface plasmon resonance (SPR) sensor. We fabricated two types of sensor chips using self-assembled monolayers (SAMs) and investigated which sensor surface exhibited higher sensitivity. In addition, anti-Bz antibody conjugated with horseradish peroxidase (HRP-Bz-Ab) was used to enhance the SPR signal. A detection limit of ca. 9ng/mL (ppb) was achieved using an immobilized 4-carboxybenzaldehyde sensor surface using SAMs containing ethylene glycol. When the HRP-Bz-Ab concentration was reduced to 30ng/mL, a detection limit of ca. 4ng/mL (ppb) was achieved for Bz.

Onodera, Takeshi; Shimizu, Takuzo; Miura, Norio; Matsumoto, Kiyoshi; Toko, Kiyoshi

295

Accurate evaluation of free-form surface profile error based on quasi particle swarm optimization algorithm and surface subdivision  

NASA Astrophysics Data System (ADS)

Although significant progress has been made in precision machining of free-form surfaces recently, inspection of such surfaces remains a difficult problem. In order to solve the problem that no specific standards for the verification of free-form surface profile are available, the profile parameters of free-form surface are proposed by referring to ISO standards regarding form tolerances and considering its complexity and non-rotational symmetry. Non-uniform rational basis spline(NURBS) for describing free-form surface is formulated. Crucial issues in surface inspection and profile error verification are localization between the design coordinate system(DCS) and measurement coordinate system(MCS) for searching the closest points on the design model corresponding to measured points. A quasi particle swarm optimization(QPSO) is proposed to search the transformation parameters to implement localization between DCS and MCS. Surface subdivide method which does the searching in a recursively reduced range of the parameters u and v of the NURBS design model is developed to find the closest points. In order to verify the effectiveness of the proposed methods, the design model is generated by NURBS and the measurement data of simulation example are generated by transforming the design model to arbitrary position and orientation, and the parts are machined based on the design model and are measured on CMM. The profile errors of simulation example and actual parts are calculated by the proposed method. The results verify that the evaluation precision of freeform surface profile error by the proposed method is higher 10%-22% than that by CMM software. The proposed method deals with the hard problem that it has a lower precision in profile error evaluation of free-form surface.

Wen, Xiulan; Zhao, Yibing; Wang, Dongxia; Zhu, Xiaochu; Xue, Xiaoqiang

2013-03-01

296

Shore-based Photogrammetry of Surface Oil Films  

NASA Astrophysics Data System (ADS)

Naturally occurring oil slicks are commonly visible in coastal waters. These slicks are suitable proxies for fuel oil spills. We took advantage of these naturally occurring slicks by developing a low-cost system to measure these features and monitor their movement. The use of low-cost digital cameras and a mapping program produces georectified animations of surface features, which can then be used to model surface oceanography, including currents and fine-scale processes such as Langmuir cells. A digital SLR camera was mounted on a bridge overlooking Portland Harbor, and it took still images every minute during daylight hours. Images were then averaged over a five minute period in order to reduce small scale variations such as boat traffic and wind waves. These mean images were then normalized to a Z-score, with the range restricted to +/- 2 standard deviations about the mean, and a threshold of approximately the lower third was used to identify slick regions. It then became possible to create a two dimensional histogram showing the probability of a slick occurring at each lat/long pixel by summing matrices over a given period. The histograms could then be constrained to various stages in the tidal cycle (e.g. high or low water), or to specific weather conditions, thus creating an atlas showing the behavior of surface features. This atlas can then be used to improve planning and pre-sighting for oil spill response in both Portland Harbor and further afield. We also found that the algorithm could also be used in other low-cost situations. Because the image is currently set to detect areas that are relatively lighter than surrounding waters, ice in the harbor showed up clearly. A digital SLR system like the one used here could therefore be used to implement a low-cost ice monitoring station. Another potential use is in red tide monitoring, which is currently being developed. Perhaps most usefully, after detecting and highlighting surface features, these highlights can be used in particle image velocimetry to model, track and interpret small scale oceanographic features for considerably lower cost and higher spatial resolutions than the current generation of many remote sensing platforms.

Whitefield, J.; Record, N.; Pershing, A. J.

2010-12-01

297

Transformer winding temperature estimation based on tank surface temperature  

NASA Astrophysics Data System (ADS)

Power transformers are among the most valuable assets of the electrical grid. Since the largest units cost in the order of millions of dollars, it is desirable to operate them in such a manner that extends their remaining lives. Operating these units at high temperature will cause excessive insulation ageing in the windings. Consequently, it is necessary to study the thermal performance of these expensive items. Measuring or estimating the winding temperature of power transformers is beneficial to a utility because this provides them with the data necessary to make informed decisions on how best to use their assets. Fiber optic sensors have recently become viable for the direct measurement of winding temperatures while a transformer is energized. However, it is only practical to install a fiber optic temperature sensor during the manufacture of a transformer. For transformers operating without fiber optic sensors, the winding temperature can be estimated with calculations using the temperature of the oil at the top of the transformer tank. When the oil temperature measurement is not easily available, the temperature of the tank surface may be used as an alternative. This paper shows how surface temperature may be utilized to estimate the winding temperature within a transformer designed for research purposes.

Guo, Wenyu; Wijaya, Jaury; Martin, Daniel; Lelekakis, Nick

2011-03-01

298

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

299

Efficient Antifouling Surface for Quantitative Surface Plasmon Resonance Based Biosensor Analysis  

PubMed Central

Non-specific binding to biosensor surfaces is a major obstacle to quantitative analysis of selective retention of analytes at immobilized target molecules. Although a range of chemical antifouling monolayers has been developed to address this problem, many macromolecular interactions still remain refractive to analysis due to the prevalent high degree of non-specific binding. In this manuscript we explore the dynamic process of the formation of self-assembled monolayers and optimize physical and chemical properties thus reducing considerably non-specific binding while maintaining the integrity of the immobilized biomolecules. As a result, analysis of specific binding of analytes to immobilized target molecules is significantly facilitated.

Nogues, Claude; Leh, Herve; Lautru, Joseph; Delelis, Olivier; Buckle, Malcolm

2012-01-01

300

Fabrication of superhydrophobic surface from binary micro-/nano-structure of mullite-whisk-based films  

NASA Astrophysics Data System (ADS)

The wettability of solid surface is a very important property of materials, which depends on both surface chemical composition and the geometry of the solid surface. We herein report a simple and inexpensive method to fabricate superhydrophobic surfaces with the use of mullite whisks (MWs) for the first time. Binary micro-/nano-structural surfaces were created by the incorporation of hydrophilic needlelike MWs with poly(?-methacryloxypropyltrimethoxysilane) to exhibit hydrophobic behavior, which further showed superhydrophobicity with water contact angle of 152.4±2? after modified with stearic acid. The wettability variation from hydrophilicity to hydrophobicity and superhydrophobicity during the assembly process are discussed based on the scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and contact-angle system. The superhydrophobicity of the surface could be attributed to the hierarchical microstructure of the rough surface induced by MWs and low surface energy of stearic acid.

Deng, Zhengyan; Yin, Yongjin; Yang, Shengyang; Wang, Cai-Feng; Chen, Su

2013-04-01

301

A Population-Average, Landmark and Surface-based (PALS) atlas of human cerebral cortex  

Microsoft Academic Search

This report describes a new electronic atlas of human cerebral cortex that provides a substrate for a wide variety of brain-mapping analyses. The Population-Average, Landmark- and Surface-based (PALS) atlas approach involves surface-based and volume-based representations of cortical shape, each available as population averages and as individual subject data. The specific PALS-B12 atlas introduced here is derived from structural MRI volumes

David C. Van Essen

2005-01-01

302

Lax pairs for the equations describing compatible nonlocal Poisson brackets of hydrodynamic type, and integrable reductions of the Lame equations  

Microsoft Academic Search

The nonlinear equations for the general nonsingular pairs of compatible nonlocal Poisson brackets of hydrodynamic type are derived and the integrability of these equations by the method of inverse scattering problem is proved. For these equations, the Lax pairs with a spectral parameter are presented. Moreover, we demonstrate the integrability of the equations for some especially important partial classes of

O. I. Mokhov

2002-01-01

303

An examination of the effects of levelingwith nickel titanium rectangular arch wires combined with torqued incisor brackets  

Microsoft Academic Search

Leveling the curve of Spee with sequential round cross-section arch wires characteristically results in incisor proclination. To prevent this, the use of low modulus, rectangular cross-section arch wires combined with torqued incisor brackets has been recommended by some clinicians. Clinical data were analyzed to determine whether this is the case. It showed that proclination does occur at a lesser angle

Stanley Braun

2001-01-01

304

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

305

Metal Work--Making a Hanging Basket Bracket. Kit No. 22. Instructor's Manual [and] Student Learning Activity Manual.  

ERIC Educational Resources Information Center

|An instructor's manual and student activity guide on making a hanging basket bracket are provided in this set of prevocational education materials which focuses on the vocational area of trade and industry (metal work). (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational…

White, Jim

306

Manipulating electromagnetic wave with the magnetic surface plasmon based metamaterials  

NASA Astrophysics Data System (ADS)

In this work, we have investigated the optical properties of the magnetic metamaterials (MMs) consisting of periodically/randomly arranged ferrite rods. By calculating the photonic band diagrams and transmittance, we have identified a photonic band gap originating from the magnetic surface plasmon (MSP) resonance. In addition, by tuning the external magnetic field (EMF), an MM slab can be used as an optical switch. Our simulated results also suggest that the optical properties of the MMs are robust against the position disorder and the size fluctuation of the ferrite rods. Moreover, by examining the relation between the transmittance and the EMF, we can optimize the EMF to realize the best switching effect. With the retrieved effective constitutive parameters ? eff and ? eff obtained from the effective-medium theory, the optimal EMF can be understood in a more clear manner.

Chen, Huajin; Liu, Shiyang

2012-05-01

307

Speaker-Adaptive Speech Recognition Based on Surface Electromyography  

NASA Astrophysics Data System (ADS)

We present our recent advances in silent speech interfaces using electromyographic signals that capture the movements of the human articulatory muscles at the skin surface for recognizing continuously spoken speech. Previous systems were limited to speaker- and session-dependent recognition tasks on small amounts of training and test data. In this article we present speaker-independent and speaker-adaptive training methods which allow us to use a large corpus of data from many speakers to train acoustic models more reliably. We use the speaker-dependent system as baseline, carefully tuning the data preprocessing and acoustic modeling. Then on our corpus we compare the performance of speaker-dependent and speaker-independent acoustic models and carry out model adaptation experiments.

Wand, Michael; Schultz, Tanja

308

An aligning auxiliary for ribbon arch brackets: rectangular boxes from ultrafine high tensile wires.  

PubMed

For the last thirty years, those using the ribbon arch brackets have disregarded the control of the apices at the start of treatment, if they have followed Begg principles. This was done for simplicity in teaching especially during the early short courses, and for anchorage purposes, yet Dr Begg's original article showed torquing control early in treatment. The problem of anchorage can now be overcome with the use of extremely light wires for bodily alignment which were not available to Dr Begg. Furthermore, clinical observations by other practitioners have confirmed the author's observation that such extremely light constant forces seem to remodel cortical bone in many patients, such as when instanding lateral incisors are brought forward. The principal reason for presenting this article is the theoretical implication--for orthodontics in general--of the possibility of cortical bone remodelling by fixed appliances. The secondary reason is that it is becoming accepted as a major advance in the Begg appliance. PMID:2152536

Mollenhauer, B

1990-10-01

309

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.

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

2013-02-01

310

Laser surface annealing of Ni-base superalloy for enhancement of material performance in hydrogen environment  

NASA Astrophysics Data System (ADS)

In the present work, laser surface annealing has been applied to an age-hardened Ni base supper alloy Inconel 718 using a 2.5kW CO2 laser to improve its performance in hydrogen environment. Laser surface annealing can produce a locally solutionized zone at the surface of Inconel 718. In the solutionized zone the age precipitates of (gamma) ' and (gamma) '' are dissolved in the matrix, and thereby the hardness of the solutionized zones is reduced to below 250Hv from approximately 450Hv of the aged base metal hardness. The surface softened zones having several hundred micro meters in depth can be obtained without melting the treated zone by controlling the laser parameters, i.e. thee defocus distance and traverse speed. Having much greater ductility than the aged base metal in hydrogen environment, the surface softened zones can effectively prevent hydrogen induced cracking, which tends to occur at the surface of a stress concentrated region. In the present case, the ductility of the surface annealed specimen is almost twice that of the base metal in a tensile test under a 29.3MPa hydrogen atmosphere at room temperature with hydrogen pre- charging. Since a controlled laser irradiation can precisely and locally anneal the surface of a stress concentrated region where hydrogen induced cracking is liable to occur, a sacrifice of strength of the structure caused by the surface softening is negligible.

Hirose, Akio; Liu, Liufa; Kobayashi, Kojiro F.

2000-11-01

311

The effects of two soft drinks on bond strength, bracket microleakage, and adhesive remnant on intact and sealed enamel.  

PubMed

The purpose of this study was to evaluate the effects of Coca-Cola and Schweppes Limón on bond strength, adhesive remnant, and microleakage beneath brackets. One hundred and twenty upper central incisor brackets were bonded to bovine incisors and divided into three groups: (1) Control, (2) Coca-Cola, and (3) Schweppes Limón. The teeth were submerged in the drinks three times a day for 15 minutes over a 15 day period. Shear bond strength (SBS) was measured with a universal testing machine, and adhesive remnant evaluated using image analysis equipment. Microleakage at the enamel-adhesive and adhesive-bracket interfaces was determined using methylene blue. One hundred and eight teeth were used for scanning electron microscopy to determine the effect of the drinks on intact and sealed enamel. SBS and adhesive remnant data were analysed using the Kruskal-Wallis test (P < 0.05) and microleakage using the Kruskal-Wallis and Mann-Whitney tests applying Bonferroni correction (P < 0.017). No significant differences were found in SBS and adhesive remnant between the groups (P > 0.05). Microleakage at the enamel-adhesive interface for groups 2 and 3 was significantly greater than for group 1 (P < 0.017). At the adhesive-bracket interface, microleakage was significantly greater in group 2 than in group 1 (P < 0.017) while microleakage in group 3 did not differ significantly from either group 1 or 2 (P < 0.017). The drinks produced enamel erosion, loss of adhesive and microleakage. Coca-Cola and Schweppes Limón did not affect the SBS of brackets or the adhesive remnant. PMID:20631082

Navarro, Raúl; Vicente, Ascensión; Ortiz, Antonio J; Bravo, Luis A

2010-07-14

312

Roth versus MBT: does bracket prescription have an effect on the subjective outcome of pre-adjusted edgewise treatment?  

PubMed

The aim was to determine if bracket prescription has any effect on the subjective outcome of pre-adjusted edgewise treatment as judged by professionals. This retrospective observational assessment study was undertaken in the Orthodontic Department of the Charles Clifford Dental Hospital, Sheffield, UK. Forty sets of post-treatment study models from patients treated using a pre-adjusted edgewise appliance (20 Roth and 20 MBT) were selected. The models were masked and shown in a random order to nine experienced orthodontic clinicians, who were asked to assess the quality of the outcome, using a pre-piloted questionnaire. The principal outcome measure was the Incisor and Canine Aesthetic Torque and Tip (ICATT) score for each of the 40 post-treatment models carried out by the nine judges. A two-way analysis of variance was undertaken with the dependent variable, total ICATT score and independent variables, Bracket prescription (Roth or MBT) and Assessor. There were statistically significant differences between the subjective assessments of the nine judges (P<0.001), but there was no statistically significant difference between the two bracket prescriptions (P = 0.900). The best agreement between a clinician's judgment of prescription used and the actual prescription was fair (kappa statistic 0.25; CI -0.05 to 0.55). The ability to determine which bracket prescription was used was no better than chance for the majority of clinicians. Bracket prescription had no effect on the subjective aesthetic judgments of post-treatment study models made by nine experienced orthodontists. PMID:22051535

Moesi, Bopelo; Dyer, Fiona; Benson, Philip E

2011-11-02

313

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

314

Bio-based hyperbranched polyurethanes for surface coating applications  

Microsoft Academic Search

High performance vegetable oil based hyperbranched polymers are not only interesting but also very useful with respect to current scenario of advanced coating materials. So in the present study hyperbranched polyurethanes have been synthesized from the monoglyceride of Mesua ferrea L. seed oil, poly(?-caprolactone)diol, 2,4-toluene diisocyanate and glycerol without using any catalyst by a two-step one pot A2+B3 approach. The

Harekrishna Deka; Niranjan Karak

2009-01-01

315

Imaging the surface of Mercury using ground-based telescopes  

Microsoft Academic Search

We describe and compare two methods of short-exposure, high-definition ground-based imaging of the planet Mercury. Two teams have recorded images of Mercury on different dates, from different locations, and with different observational and data reduction techniques. Both groups have achieved spatial resolutions of <250km, and the same albedo features and contrast levels appear where the two datasets overlap (longitudes 270–360°).

Michael Mendillo; Johan Warell; Sanjay S. Limaye; Jeffrey Baumgardner; Ann Sprague; Jody K. Wilson

2001-01-01

316

Imaging the surface of Mercury using ground-based telescopes  

Microsoft Academic Search

We describe and compare two methods of short-exposure, high-de4nition ground-based imaging of the planet Mercury. Two teams have recorded images of Mercury on di+erent dates, from di+erent locations, and withdi+erent observational and data reduction tech niques. Both groups have achieved spatial resolutions of ¡ 250 km, and the same albedo features and contrast levels appear where the two datasets overlap

Michael Mendillo; Sanjay S. Limaye; Jody K. Wilson

317

Editable polycube map for GPU-based subdivision surfaces  

Microsoft Academic Search

In this paper we propose an editable polycube mapping method that, given an arbitrary high-resolution polygonal mesh and a simple polycube representation plus optional sketched features indicating relevant correspondences between the two, provides a uniform, regular and artist-controllable quads-only mesh with a parameterized subdivision scheme. The method introduces a global parameterization, based on a divide and conquer strategy, which allows

Jiazhil Xia; Ismael Garcia; Ying He; Shi-Qing Xin; Gustavo Patow

2011-01-01

318

Surface plasmon resonance based infrared photo-detectors  

NASA Astrophysics Data System (ADS)

At present materials can be engineered to control propagation of light in certain directions at certain wavelengths. Such materials are called photonic crystals which contain a periodic arrangement of metals and dielectric materials on a wavelength scale. Surface Plasmon Resonances (SPR) in metallic and dielectric nano-arrays can be used to enhance the response of photo-detectors. There are variety of potential ways to increase the performance of infrared photo-detectors by using electromagnetic enhancement and dependence of the resonance wavelength on the arrays size, shape and the local dielectric environment integration of these apertures. A detailed analysis of the optical properties of the waveguides in two and three dimensions with periodically perforated array structures is presented. Transmission and reflection spectra, resonant modes and field patterns of photonic crystals were calculated and imaged with using FDTD (Finite-difference Time-domain) method by numerical analysis of the non-linear dispersion relation. Additionally, by varying the orientation of holes on the wave-guide, polarization sensitivity was achieved in the model.

Aytac, Yigit; Perera, Unil

2012-03-01

319

Surface-Based Respiratory Motion Classification and Verification  

NASA Astrophysics Data System (ADS)

To ensure precise tumor irradiation in radiotherapy a stable breathing pattern is mandatory as tumors are moving due to respiratory motion. Consequentially, irregularities of respiratory patterns have to be detected immediately. The causal motion of tissue also differs due to different physiological types of respiration, e.g., chest-or abdominal breathing. Currently used devices to measure respiratory motion do not incorporate complete surface deformations. Instead only small regions of interest are considered. Thereby, valuable information to detect different breathing patterns and types are lost. In this paper we present a system that uses a novel camera sensor called Time-of-Flight (ToF) for automatic classification and verification of breathing patterns. The proposed algorithm calculates multiple volume signals of different anatomical regions of the upper part of the patient’s body. Therefore disjoint regions of interest are defined for both, the patient’s abdomen and thorax. Using the calculated volume signals the type of respiration is determined in real-time by computing an energy coefficient. Changing breathing patterns can be visualized using a 2-D histogram, which is also used to classify and detect abnormal breathing phases. We evaluated the proposed method on five persons and obtained a reliable differentation of chest- and abdominal breathing in all test cases. Furthermore, we could show that the introduced 2-D histogram enables an accurate determination of changing breathing patterns.

Müller, Kerstin; Schaller, Christian; Penne, Jochen; Hornegger, Joachim

320

Surface EMG force modeling with joint angle based calibration.  

PubMed

In this paper, a calibration method to compensate for changes in SEMG amplitude with joint angle is introduced. Calibration factors were derived from constant amplitude surface electromyogram (SEMG) recordings from the biceps brachii (during elbow flexion) and the triceps brachii (during elbow extension) across seven elbow joint angles. SEMG data were then recorded from the elbow flexors (biceps brachii and brachioradialis) and extensors (triceps brachii) during isometric, constant force flexion and extension contractions at the same joint angles. The resulting force at the wrist was measured. The fast orthogonal search method was used to find a mapping between the system inputs - estimated SEMG amplitudes and joint angle - and the system output - measured force, for both calibrated and non-calibrated SEMG data. Models developed with calibrated data yielded a statistically significant improvement in force estimation compared to models developed with non-calibrated data, suggesting that the calibration method can compensate for changes in the SEMG-force relationship with changing joint angle. It was also found that the number of non-linear, joint angle-dependent terms used in the SEMG-force model was reduced with calibration. Additionally, initial inter-session analysis performed for four subjects suggests that calibration values can be used for subsequent recording sessions, and different output force levels. PMID:23273763

Hashemi, Javad; Morin, Evelyn; Mousavi, Parvin; Hashtrudi-Zaad, Keyvan

2012-12-25

321

Wavelet-Based Surface Wave Tomography in Southern Taiwan  

NASA Astrophysics Data System (ADS)

In surface-wave dispersion studies, measurements of phase and/or group velocities are always obtained with pre-determined resolutions in time and frequency domains. Wavelet analysis reveals and exploits wave-packets' intrinsically complementary spectral-temporal characteristics. In this study, we employ the Geophysical Wavelet Library (GWL, http://users.math.uni-potsdam.de/~gwl/) to identify different groups of signals and investigate their dispersive and dissipative properties between two stations. Possible biases in measurements caused by the choice of basis functions in model space and contamination of diffracted waves are corrected according to the frequency-dependent phase misfits. Synthetic tests are conducted using both spherically symmetric and 3D heterogeneous models to verify the reliability of this method. We apply this approach to the broadband records from stations in the South Taiwan Transect Array, a roughly linear deployment of 25 stations with an average inter-station distance of about 5 km. Shear-wave structure obtained from inversion of phase velocity measurements shows different patterns beneath Taiwan across the boundary between the Western Foothills and the Central Range. Eastern Taiwan possesses a fast anomaly at shallow depth (~20km) but a slow anomaly at deep (~40km). Despite poor resolution at depth <10km, our model has a lateral resolving power of less than 20km and provides better constraints down to 80-km depth, which can not be achieved by current local body-wave tomography.

Yang, H.; Zhao, L.; Hung, S.; Huang, B.

2011-12-01

322

Spline-based models for predictiveness curves and surfaces  

PubMed Central

A biomarker is defined to be a biological characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. The use of biomarkers in cancer has been advocated for a variety of purposes, which include use as surrogate endpoints, early detection of disease, proxies for environmental exposure and risk prediction. We deal with the latter issue in this paper. Several authors have proposed use of the predictiveness curve for assessing the capacity of a biomarker for risk prediction. For most situations, it is reasonable to assume monotonicity of the biomarker effects on disease risk. In this article, we propose the use of flexible modelling of the predictiveness curve and its bivariate analogue, the predictiveness surface, through the use of spline algorithms that incorporate the appropriate monotonicity constraints. Estimation proceeds through use of a two-step algorithm that represents the “smooth, then monotonize” approach. Subsampling procedures are used for inference. The methods are illustrated to data from a melanoma study.

Ghosh, Debashis; Sabel, Michael

2010-01-01

323

An oriented particle level set method based on surface coordinates  

NASA Astrophysics Data System (ADS)

In this work we present a new method for tracking evolving interfaces. Like the Adaptive Oriented Particle Level Set method (AOPLS, Ianniello and Mascio, 2010), it uses a combination of unconnected particles containing geometric information and a level set function to track the interface. In the present method, the geometric information, solved for in each particle, is a set of tangent vectors and the corresponding curvature tensor of the interface. Compared to the AOPLS method, the amount of geometric data stored in each particle is roughly halved, while still retaining a description of the interface that includes both orientation and curvature. A mechanism for ensuring a sufficiently dense distribution of particles on the interface is also included. From the information stored in each particle, a "continuous" representation of the interface is obtained by transferring the information to a level set function stored on an Eulerian grid. Unlike the AOPLS method, the present method takes the curvature into account when the zero level set is constructed. This results in significant improvements in regions of high curvature. Two different formulations of the new method have been explored. In the first, the tangent vectors deform purely according to the velocity field. In the second, the tangent vectors are forced to coincide with the principal directions of the surface. Both formulations are shown to be applicable.

Vartdal, Magnus; Bøckmann, Arne

2013-10-01

324

Biodegradation-based Polymer Surface Erosion and Surface Renewal for Foul-release at Low Ship Speeds  

Microsoft Academic Search

Non-toxic foul-release provides an environmentally friendly and sustainable technical solution to control micro- and\\/or macrofouling on ships' hulls. Silicone-based coatings have been used for foul-release at high or moderate ship speeds (>15 knots). To remove the fouling from slower ships (<15 knots), the macrofoulers in particular, biodegradable polymers may be used to make the coating surface self-renewable. Synthesized by microorganisms

Jian Yu

2003-01-01

325

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

PubMed

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

2012-10-15

326

R -mapping based method for designing of form cutting tool for sculptured surface machining  

Microsoft Academic Search

Computer-aided design (CAD) and computer-aided machining (CAM) of sculptured surfaces sometimes present problems that were not envisioned in classical differential geometry. This paper presents mathematical results that pertain to designing a form-cutting tool for machining a given sculptured surface on a multiaxis NC machine. The results obtained below are based on a new kind of surface mapping—on the so-called R-mapping

S. P. Radzevich

2002-01-01

327

Neural network based predication and optimization for groundwater/surface water system  

US Patent & Trademark Office Database

The present invention relates to a method and apparatus, based on the use of a neural network (NN), for (a) predicting important groundwater/surface water output/state variables, (b) optimizing groundwater/surface water control variables, and/or (c) sensitivity analysis, to identify physical relationships between input and output/state variables used to model the groundwater/surface water system or to analyze the performance parameters of the neural network.

2007-08-07

328

MEMS based high-impedance surface for millimetre wave dielectric rod waveguide phase shifter  

Microsoft Academic Search

Analogue type millimetre wave phase shifter based on a dielectric rod waveguide with adjacent MEMS tuneable high-impedance surface is proposed. Applying bias voltage to the MEMS varactors of the high-impedance surface allow controlling its effective impedance and consequently the phase factor of the propagation constant inside the waveguide. The measured phase difference between the phase shifter with adjacent high-impedance surface

Dmitry Chicherin; Mikael Sterner; Joachim Oberhammer; Sergey Dudorov; Dmitri Lioubtchenko; Antti J. Niskanen; Victor Ovchinnikov; Antti V. Räisänen

2010-01-01

329

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

330

Surface roughness prediction based on processing parameters in abrasive jet finishing with grinding wheel as restraint  

Microsoft Academic Search

Based on the modeling and experiments concerning the surface roughness in abrasive jet finishing with grinding wheel as restraint, the effect of abrasive size, abrasive fluid concentration, machining cycles, wheel velocity and carrier fluid on machined surface quality was investigated. Surface grinder KP-36 was employed in a jet machining experiment conducted with W18Cr4V and 40Cr materials, profilometer TALYSURF was used

Li Changhe; Mao Weiping; Du Chao; Liu Zhanrui

2010-01-01

331

Fractal-Based Modeling of Radio-Wave Scattering from the Surface of Venus  

Microsoft Academic Search

The use of fractal geometry has become increasingly attractive both as a model for natural surfaces and as the basis for a new generation of radio-wave scattering laws. The apparent advantages of the fractal-based (F-B) laws over classical laws, which typically are parameterized by a surface power reflection coefficient and a surface RMS slope-related parameter, are that (i) F-B laws

G. L. Tyler; A. K. Sultan-Salem

2005-01-01

332

Efficient infrared thermal emitters based on low-albedo polaritonic meta-surfaces  

NASA Astrophysics Data System (ADS)

A low-albedo all-semiconductor meta-surface with spectrally selective absorption peaks is demonstrated. By engineering the dimensions and shapes of the semiconductor antennas comprising the meta-surface, simultaneous reduction of reflectivity and enhancement of absorption are accomplished by controlling their electric and magnetic resonances. Thermal emissivity of the silicon carbide-based meta-surface is experimentally measured and found in agreement with both absorption measurements and theoretical predictions.

Neuner, Burton; Wu, Chihhui; Eyck, Gregory Ten; Sinclair, Michael; Brener, Igal; Shvets, Gennady

2013-05-01

333

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

334

Multivariate Tensor-based Brain Anatomical Surface Morphometry via Holomorphic One-Forms  

PubMed Central

Here we introduce multivariate tensor-based surface morphometry using holomorphic one-forms to study brain anatomy. We computed new statistics from the Riemannian metric tensors that retain the full information in the deformation tensor fields. We introduce two different holomorphic one-forms that induce different surface conformal parameterizations. We applied this framework to 3D MRI data to analyze hippocampal surface morphometry in Alzheimer’s Disease (AD; 26 subjects), lateral ventricular surface morphometry in HIV/AIDS (19 subjects) and cortical surface morphometry in Williams Syndrome (WS; 80 subjects). Experimental results demonstrated that our method powerfully detected brain surface abnormalities. Multivariate statistics on the local tensors outperformed other TBM methods including analysis of the Jacobian determinant, the largest eigenvalue, or the pair of eigenvalues, of the surface Jacobian matrix.

Wang, Yalin; Chan, Tony F.; Toga, Arthur W.; Thompson, Paul M.

2010-01-01

335

Multivariate tensor-based brain anatomical surface morphometry via holomorphic one-forms.  

PubMed

Here we introduce multivariate tensor-based surface morphometry using holomorphic one-forms to study brain anatomy. We computed new statistics from the Riemannian metric tensors that retain the full information in the deformation tensor fields. We introduce two different holomorphic one-forms that induce different surface conformal parameterizations. We applied this framework to 3D MRI data to analyze hippocampal surface morphometry in Alzheimer's Disease (AD; 26 subjects), lateral ventricular surface morphometry in HIV/AIDS (19 subjects) and cortical surface morphometry in Williams Syndrome (WS; 80 subjects). Experimental results demonstrated that our method powerfully detected brain surface abnormalities. Multivariate statistics on the local tensors outperformed other TBM methods including analysis of the Jacobian determinant, the largest eigenvalue, or the pair of eigenvalues, of the surface Jacobian matrix. PMID:20426005

Wang, Yalin; Chan, Tony F; Toga, Arthur W; Thompson, Paul M

2009-01-01

336

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

337

Effects of oxide charge and surface recombination velocity on the excess base current of BJTs  

SciTech Connect

The role of net positive oxide trapped charge and surface recombination velocity on excess base current in BJTs is identified. The effects of the two types of damage can be detected by plotting the excess base current versus base-emitter voltage. Differences and similarities between ionizing-radiation-induced and hot electron-induced degradation are discussed.

Kosier, S.L.; Schrimpf, R.D.; Wei, A. [Univ. of Arizona, Tucson, AZ (United States); DeLaus, M. [Analog Devices, Inc., Woburn, MA (United States); Fleetwood, D.M. [Sandia National Labs., Albuquerque, NM (United States); Combs, W.E. [NSWC-Crane, IN (United States)

1993-12-01

338

Uncertainty Analysis of Power System Components Based on Stochastic Response Surfaces  

Microsoft Academic Search

The output of a power system analysis mostly requires extensive knowledge and correct handling of input uncertainties. Analytical approaches often depend on simplified models whereas Monte Carlo based sampling methods are often time consuming. This paper presents an uncertainty analysis based on a limited number of well chosen samples which are used to model a stochastic response surface, based on

C. Bastiaensen; W. Deprez; E. Haesen; J. Driesen; R. Belmans

2008-01-01

339

Improving satellite-based rainfall estimates over land using spaceborne surface soil moisture retrievals  

Technology Transfer Automated Retrieval System (TEKTRAN)

Over land, remotely-sensed surface soil moisture and precipitation accumulation retrievals contain complementary information that can be exploited for the mutual benefit of both products. Here a Kalman filtering based tool is developed that utilizes a time series of spaceborne surface soil moisture ...

340

Statistics of Antarctic surface meteorology based on hourly data in 1957e2007 at Syowa Station  

Microsoft Academic Search

Statistical characteristics of the surface meteorology are examined at Syowa Station (69? 000S, 39? 350E), which is located on an island near the coastal region of the Antarctic continent, based on operational observations made over the 50-year period from February 1957 through January 2007, which includes missing periods equivalent to 5 years. Statistics are obtained for the surface temperature, sea

Kaoru Sato; Naohiko Hirasawa

2007-01-01

341

Interferometric surface plasmon resonance based on low-cost grating substrates  

Microsoft Academic Search

Surface plasmon resonance (SPR) has been used for some time in chemical and biological sensors. Some of the schemes for exciting surface plasmons include prisms and gratings. Grating-based optical SPR sensors have been demonstrated, which use light intensity variations at resonance or wavelength interrogation. Recently, a gold grating made from a commercial recordable compact disk was used for excitation of

N. Sedoglavich; R. Künnemeyer; S. R. Talele; J. C. Sharpe

2007-01-01

342

Multichannel surface EMG based estimation of bilateral hand kinematics during movements at multiple degrees of freedom  

Microsoft Academic Search

The paper proposes a method to estimate wrist kinematics from surface EMG signals for proportional and simultaneous control of multiple degrees of freedom (DOFs). The approach is based on the concurrent detection of surface EMG signals from forearm muscles and hand kinematics of both limbs during mirrored bilateral movements in free space which involve the simultaneous activation of wrist flexion\\/extension,

Silvia Muceli; Ning Jiang; Dario Farina

2010-01-01

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

Target-Localized Nanograting-Based Surface Plasmon Resonance Detection toward Label-free Molecular Biosensing  

Microsoft Academic Search

We explore the sensitivity enhancement of label-free detection based on localized surface plasmon resonance using surface-relief nanograting structures. A nanograting structure was modeled, so that target molecular interactions are localized in hot spots of the near fields. The nanograting structure was optimized numerically for the highest enhancement of sensitivity with hybridization between complementary strands of DNA as the model target

Kyungjae Ma; Dong Jun Kim; Kyujung Kim; Seyoung Moon; Donghyun Kim

2010-01-01

345

A model-based four-dimensional left ventricular surface detector  

Microsoft Academic Search

The authors have developed a general model-based surface detector for finding the four-dimensional (three spatial dimensions plus time) endocardial and epicardial left ventricular boundaries. The model encoded left ventricular (LV) shape, smoothness, and connectivity into the compatibility coefficients of a relaxation labeling algorithm. This surface detection method was applied to gated single photon emission computed tomography (SPECT) perfusion images, tomographic

Tracy L. Faber; Ernest M. Stokely; Ronald M. Peshock; James R. Corbett

1991-01-01

346

Detecting the motor unit action potential from surface EMG signals based on wavelet transform  

Microsoft Academic Search

Due to the poor temporal resolution of surface EMG signals, it is a challenging task to detect the motor unit action potential (MUAP) directly from the surface EMG signals. In this paper, a novel method based on wavelet transform was proposed to enhance the temporal resolution. In the method, some thresholds were applied to process all of the wavelet coefficients

Xiao Hu; Zhizhong Wang

2004-01-01

347

Theory and experiment of novel frequency selective surface based on substrate integrated waveguide technology  

Microsoft Academic Search

A novel frequency selective surface (FSS) based on substrate integrated waveguide (SIW) technology is investigated with simulation and experiment. The periodic unit is made of a SIW cavity with slots on the top and bottom surfaces, and the whole FSS is fabricated on a microwave substrate with standard PCB process. The high-Q property of SIW cavities greatly improved the frequency

Guo Qing Luo; Wei Hong; Zhang-Cheng Hao; Bing Liu; Wei Dong Li; Ji Xin Chen; Hou Xing Zhou; K. Wu

2005-01-01

348

Electrowetting-based control of droplet transition and morphology on artificially microstructured surfaces  

Microsoft Academic Search

Electrowetting (EW) has recently been demonstrated as a powerful tool for controlling droplet morphology on smooth and artificially structured surfaces. The present work involves a systematic experimental investigation of the influence of electrowetting in determining and altering the state of astatic droplet resting on an artificially microstructured surface. Extensive experimentation is carried out to benchmark a previously developed energy-minimization-based model

Vaibhav Bahadur; Suresh V. Garimella

2008-01-01

349

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

350

Digital elevation map reconstruction for port-based dynamic simulation of contacts on irregular surfaces  

Microsoft Academic Search

This paper presents a method to utilize a port- based multibody contact model for simulating dynamic interac- tion between irregular surfaces. The existing compliant contact model requires an analytic parametrization of the surfaces involved in the interaction, the definition of a Gauss frame in each of the contact points and initialization of the candidate contact points. The authors intend to

Martin Wassink; Raffaella Carloni; Pantelis Poulakis; Stefano Stramigioli

2009-01-01

351

Surface modification of starch based biomaterials by oxygen plasma or UV-irradiation  

Microsoft Academic Search

Radiation is widely used in biomaterials sci- ence for surface modification and sterilization. Herein, we describe the use of plasma and UV-irradiation to improve the biocompatibility of different starch-based blends in terms of cell adhesion and proliferation. Physical and chemical changes, introduced by the used methods, were evaluated by complementary techniques for surface anal- ysis such as scanning electron microscopy,

Iva Pashkuleva; Alexandra P. Marques; Filipe Vaz; Rui L. Reis

2009-01-01

352

A Model-Based Inversion of Rough Soil Surface Parameters From Radar Measurements  

Microsoft Academic Search

In this paper, a model-based retrieval algorithm is developed for the remote sensing of rough surfaces. The probabilistic and sensitive issues of parameter estimation for soil surfaces are discussed and modeled. A geophysical model function (GMF) that relates the input (observation space) and output vectors (parameter space) includes both an electromagnetic scattering model and a dielectric model; the electromagnetic scattering

K. S. Chen; T. D. Wu; J. C. Shi

2001-01-01

353

Bipedal robot walking strategy on inclined surfaces using position and orientation based inverse kinematics algorithm  

Microsoft Academic Search

This paper proposes a strategy for bipedal robot walking on inclined surfaces using position and orientation based inverse kinematics algorithm. Some researchers implemented control approaches to solve bipedal walking on inclined surfaces. Generally, most of them apply control feedback at ankle joints and also introduced many more control methodologies. In this paper, inverse kinematics methodology is introduced systematically for bipedal

Fariz Ali; Aliza Che Amran; Atsuo Kawamura

2010-01-01

354

Fully automated Liquid Extraction-Based Surface Sampling and Ionization Using a Chip-Based Robotic Nanoelectrospray Platform  

SciTech Connect

A fully automated liquid extraction-based surface sampling device utilizing an Advion NanoMate chip-based infusion nanoelectrospray ionization system is reported. Analyses were enabled for discrete spot sampling by using the Advanced User Interface of the current commercial control software. This software interface provided the parameter control necessary for the NanoMate robotic pipettor to both form and withdraw a liquid microjunction for sampling from a surface. The system was tested with three types of analytically important sample surface types, viz., spotted sample arrays on a MALDI plate, dried blood spots on paper, and whole-body thin tissue sections from drug dosed mice. The qualitative and quantitative data were consistent with previous studies employing other liquid extraction-based surface sampling techniques. The successful analyses performed here utilized the hardware and software elements already present in the NanoMate system developed to handle and analyze liquid samples. Implementation of an appropriate sample (surface) holder, a solvent reservoir, faster movement of the robotic arm, finer control over solvent flow rate when dispensing and retrieving the solution at the surface, and the ability to select any location on a surface to sample from would improve the analytical performance and utility of the platform.

Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2010-01-01

355

Chip-Scale Bioassays Based on Surface-Enhanced Raman Scattering: Fundamentals and Applications.  

National Technical Information Service (NTIS)

This work explores the development and application of chip-scale bioassays based on surface-enhanced Raman scattering (SERS) for high throughput and high sensitivity analysis of biomolecules. The size effect of gold nanoparticles on the intensity of SERS ...

H. Y. Park

2005-01-01

356

Photonic Devices Based on Surface and Composition-Engineered Infrared Colloidal Nanocrystals.  

National Technical Information Service (NTIS)

The goal of the ARO sponsored project is to develop advanced photonic devices based on surface and composition engineered semiconductor nanocrystals. The PI's laboratory has successfully carried out and exceeded the proposed goals of the project with a se...

J. Xu

2012-01-01

357

Evaluation of Crosslinking Methods and Characterization of Surface Features of a Collagen-Based Dermal Equivalent.  

National Technical Information Service (NTIS)

This work involves the development and testing of a new crosslinking method used in preparation of a collagen-based dermal equivalent. In addition to this, the sponge surface characteristics and the control of these characteristics has been studied. This ...

C. F. Whyne

1984-01-01

358

Transient localizations in metals using microstructure-based yield surfaces  

NASA Astrophysics Data System (ADS)

Classical constitutive models of phenomenological plasticity/viscoplasticity rely heavily on yield functions to distinguish plastic flow from reversible elastic deformation. Physically based yield functions are utilized here for body-centred cubic (bcc) and face-centred cubic (fcc) types of metal structures in investigating necking and dynamic shear localizations over a wide range of temperatures and strain rates. The consistency model is employed in determining the increment of the viscoplastic multiplier and consequently a proper definition for the continuum elasto-viscoplastic tangent modulus is derived. Mesh-independent results are obtained using the finite element analysis in investigating the localization behaviour for tantalum, vanadium and niobium for bcc metals and OFHC copper for fcc metals.

Voyiadjis, G. Z.; Abed, F. H.

2007-01-01

359

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

2010-12-22

360

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

Microsoft Academic Search

We investigated the effects of different Er:YAG laser treatments on the surface roughness of base metal alloys. A total of\\u000a 36 specimens were prepared of two base metal alloys (Wiron 99, Bellabond plus). The surfaces of the specimens were standardized\\u000a by gradual wet grinding with 320-, 600-, 800- and 1,000-grit silicon carbide paper for 10 s each on a grinding machine

Göknil Ergün Kunt; Ahmet Umut Güler; Gözlem Ceylan; ?brahim Duran; Pelin Özkan; Tu?rul Kirtilo?lu

361

Worn surface characteristics of Cu-based powder metallurgy bake materials for aircraft  

Microsoft Academic Search

Cu-based powder metallurgy brake materials are used for aircraft widely and successfully. The characteristics of worn surface of Cu-based powder metallurgy brake materials for aircraft after working under service condition were studied, and two main wear mechanisms were discussed. The results show that the main components of worn surface are graphite. SiO2, Fe, Cu and oxide of Fe (Fe3O4 and

Ping-ping YAO; Hong-chao SHENG; Xiang XIONG; Bai-yun HUANG

2007-01-01

362

Image-based rendering of intersecting surfaces for dynamic comparative visualization  

Microsoft Academic Search

Nested or intersecting surfaces are proven techniques for visualizing shape differences between static 3D objects (Weigle\\u000a and Taylor II, IEEE Visualization, Proceedings, pp. 503–510, 2005). In this paper we present an image-based formulation for these techniques that extends their use to dynamic scenarios, in\\u000a which surfaces can be manipulated or even deformed interactively. The formulation is based on our new layered rendering

Stef Busking; Charl P. Botha; Luca Ferrarini; Julien Milles; Frits H. Post

2011-01-01

363

Wave energy in surface layers for energy-based damage evaluation  

Microsoft Academic Search

Seismic wave energy in surface layers is calculated based on vertical array records at four sites during the 1995 Hyogo-ken Nambu earthquake by assuming vertical propagation of SH waves. The upward energy generally tends to decrease as it goes up from the base layer to the ground surface particularly in soft soil sites. Theoretical study on 1D multi-layers model to

Takaji Kokusho; Ryuichi Motoyama; Hiroshi Motoyama

2007-01-01

364

The spreading behaviour and spreading mechanism of new glucosamide-based trisiloxane on polystyrene surfaces  

Microsoft Academic Search

In order to evaluate the spreading behaviour of new glucosamide-based trisiloxane surfactants on hydrophobic surfaces, the time- and concentration-dependent spreading performance was investigated. Dynamic light scattering (DLS) was applied to investigate the role of surfactant aggregates on the spreading process. The results suggest that glucosamide-based trisiloxane surfactants show superspreading behaviour on hydrophobic surfaces; however, the spreading mechanism differs from that

Yue Zhang; Fu Han

2009-01-01

365

Surface Morphology and X-Ray Diffraction Analysis for Silicon Nanocrystal-Based Heterostructures  

NASA Astrophysics Data System (ADS)

In this work, we studied the effect of rapid thermal oxidation process on the structural and surface morphology of silicon nanocrystal-based heterostructures. PLD technique was employed in combination with rapid thermal oxidation process to form multilayers heterostructures. Results show the dependence of the surface roughness and structure on the oxidation temperature. Best surface morphology was achieved at 723 K oxidation temperature, at which, the X-ray diffraction result ensured the formation of the Cu2O phase at (111) and (002) diffraction plain with uniform porous surface.

Salim, Evan T.

2013-10-01

366

Modeling of Si-based solar cells with V-grooved surface texture by crosslight APSYS  

Microsoft Academic Search

Based on Crosslight APSYS, two-dimensional simulations have been performed on Si-based solar cell devices especially those with V-grooved surface texture. These Si-based solar cells include rear-contacted cells and passivated emitter, rear totally diffused cells etc. The APSYS simulator is based on drift-diffusion theory with many advanced features. It can enable an efficient computation across the whole solar spectra by taking

Y. G. Xiao; M. Lestrade; Z. Q. Li; Z. M. S. Li

2007-01-01

367

Evaluation of Surface Deflection in Automobile Exterior Panel by Curvature Based Method  

NASA Astrophysics Data System (ADS)

Surface deflections in exterior panel have a great effect on the external appearance of automobiles. Usually, they are occurred on large flat panels containing sudden shape changes and shows very small amplitude. Traditional methods for detecting surface deflections on stamped automobile panels are scratching the surface with a wheatstone with oil, rubbing the surface with technician's fingers, or reflecting light on the surface. All of these methods rely on a technician's sense. In this study, a curvature based method was proposed to detect and quantify the surface deflection. The measure of surface deflection was defined as the variation of curvature difference between tool and blank. The degree of surface deflection can be predicted by the correlation between the proposed measure and visual inspection. Today's simulation code has enough accuracy to predict surface deflection by using the proposed method. The appropriate simulation method to find the surface deflections accurately were studied. As a verification example, a shallow rectangular drawing with rectangular embossing was studied. The corresponding experiment was carried out. The simulation and experiment were compared and investigated to prove the effectiveness of the proposed method and the effectiveness of prediction.

Chung, W. J.; Kim, W. S.; Kim, J. H.; Seo, J. H.; Jung, T. C.

2011-08-01

368

The Spinning Membrane, SUPER-SU(?)-GAUGE Theories and Moyal Brackets  

NASA Astrophysics Data System (ADS)

Several important topics concerning the membrane and its symmetries are discussed. The fact that a space-time-independent Lagrangian density for a gauge-field configuration of a (d - 1)-dimensional SU(?) super Yang-Mills theory, reduced to one dimension (time), is equivalent to a Green-Schwarz formalism of the Euclidean Eguchi-Schild string action in d - 1 dimensions, naturally raises the question whether one can construct a Neveu-Ramond-Schwarz analog. The answer is in the negative; the world-sheet supersymmetric extension of the Eguchi-Schild action for the string cannot be viewed as a classical-vacuum configuration of a super-SU(?)-gauge theory. For the second topic we construct a "supersymmetry" charge operator, Qf, which plays the role of a residual fermionic symmetry, for fixed time, of the light-cone spinning membrane. It is explicitly shown how the Yang-Mills type of actions and, in particular, the ones for vacuum-field configurations, associated with Q(?) supergauge theories, are invariant under both Qf "supersymmetry" and the superalgebra of area-preserving superdiffeomorphisms of the light-cone spinning torus membrane, Q(?). More general actions can be constructed which are invariant under deformations of this superalgebra. In this case the ordinary (graded) Poisson brackets are replaced by super Moyal brackets. Finally, we conjecture why these actions, in analogy with what happens with the light-cone supermembrane, should correspond to a superfiber bundle (over space-time) formulation of the supersymmetric-gauge quantum-mechanical models (SGQMM's) of Flume and Baake et al.; with the general supergroup of trigonometric structure constants of Fairlie, Fletcher and Zachos as the structure supergroup of the superfiber. To support our concluding conjecture, preliminary steps are outlined which are necessary in order to fix the light-cone gauge for the spinning-membrane action. We discuss why the Qf "supersymmetry" (the remnant world-volume light-cone local supersymmetry) and the Q(?) supergauge transformations must arise as its residual symmetries.

Castro, Carlos

369

A Framework of a Model-based Simulation System for Predicting Surface Generation in Ultra-precision Raster Milling of Freeform Surfaces  

Microsoft Academic Search

The fabrication of high quality freeform surfaces used in many photonics and telecommunication products is based on ultra-precision raster milling which allows direct machining of the freeform surfaces with sub- micrometric form accuracy and nanometric surface finish. However, the achievement of a superior mirror finish still depends largely on the experience and skills of the machine operators through an expensive

C. F. Cheung; W. B. Lee

370

Microbial control of food-related surfaces: Na-Chlorophyllin-based photosensitization.  

PubMed

The aim of this study was to evaluate efficiency of photosensitization as surface sanitation alternative using model systems when food pathogens, their spores and biofilms were attached to the food-related surface (polyolefine). In addition it was important to compare antibacterial efficiency of Na-Chlorophyllin (Na-Chl)-based photosensitization with conventional sanitizers. Obtained results indicate that Bacilluscereus ATCC 12826 and Listeriamonocytogenes ATCC 7644 as well as their thermoresistant strains B.cereus SV90 and L.monocytogenes 56LY were effectively inactivated (7 log) by Na-Chl-based photosensitization in vitro. Inactivation rate of thermoresistant strains was slower. The number of attached to the surface B.cereus ATCC 12826 and L.monocytogenes ATCC 7644 was reduced from 4-4.5 log to 0 log after photosensitization treatment. To achieve adequate inactivation of thermoresistant strains the higher Na-Chl concentration and longer illumination times had to be used. Comparison of different surface decontamination treatments reveal that photosensitization is much more effective against all surface-attached B.cereus and L.monocytogenes strains than washing with water or 200 ppm Na-hypochlorite. It is important to note, that surface-attached B.cereus spores and L.monocytogenes biofilms can be eliminated from it by photosensitization as well. Our data support the idea that Na-Chlorophyllin-based photosensitization has high antibacterial potential which may serve in the future for the development of human and environment friendly, non-thermal surface decontamination technique. PMID:21807530

Luksiene, Zivile; Paskeviciute, Egle

2011-07-23

371

Band-structure-based collisional model for electronic excitations in ion-surface collisions  

SciTech Connect

Energy loss per unit path in grazing collisions with metal surfaces is studied by using the collisional and dielectric formalisms. Within both theories we make use of the band-structure-based (BSB) model to represent the surface interaction. The BSB approach is based on a model potential and provides a precise description of the one-electron states and the surface-induced potential. The method is applied to evaluate the energy lost by 100 keV protons impinging on aluminum surfaces at glancing angles. We found that when the realistic BSB description of the surface is used, the energy loss obtained from the collisional formalism agrees with the dielectric one, which includes not only binary but also plasmon excitations. The distance-dependent stopping power derived from the BSB model is in good agreement with available experimental data. We have also investigated the influence of the surface band structure in collisions with the Al(100) surface. Surface-state contributions to the energy loss and electron emission probability are analyzed.

Faraggi, M.N. [Instituto de Astronomia y Fisica del Espacio, CONICET, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Gravielle, M.S. [Instituto de Astronomia y Fisica del Espacio, CONICET, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, FCEN, Universidad de Buenos Aires, Buenos Aires (Argentina); Alducin, M.; Silkin, V.M. [Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastian (Spain); Juaristi, J.I. [Departamento de Fisica de Materiales Facultad de Quimicas, UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Unidad de Fisica de Materiales Centro Mixto CSIC-UPV/EHU, Facultad de Quimicas, UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain)

2005-07-15

372

An index to assess hydromorphological quality of Estonian surface waters based on macroinvertebrate taxonomic composition  

Microsoft Academic Search

We developed an index (MESH –Macroinvertebrates in Estonia: Score of Hydromorphology) to assess hydromorphological quality of Estonian surface waters based on macroinvertebrate taxonomic composition. The MESH is an average score based on the affinities of selected indicator taxa to flow velocity and bottom type. As both parameters were highly correlated (r=0.65) indicator response to both parameters were combined. The list

Henn Timm; Kairi Käiro; Tõnu Möls; Taavi Virro

2011-01-01

373

Study on Fruit Quality Inspection Based on Its Surface Color in Produce Logistics  

Microsoft Academic Search

A novel non-invasive and nondestructive fruit quality inspection method for produce logistics is proposed in this paper based on fruits' surface color. In this method, an image of fruits is firstly taken, which is in the RGB color model. The image is then transferred from the RGB color model to the HSI color model, and is segmented based on hue

Yizhong Wang; Yanhua Cui; George Q. Huang; Ping Zhang; Shaohui Chen

2010-01-01

374

Workpiece Surface Integrity and Tool Life Issues When Turning Inconel 718™ Nickel Based Superalloy  

Microsoft Academic Search

Inconel 718 is one of a family of nickel-based superalloys which are used extensively in the aerospace industry in the hot sections of gas turbine engines. The literature detailing the effects of varying operating parameters on tool life when machining nickel based superalloys is comprehensive, however, relatively little of this data refers to their effects on machined workpiece surface integrity.

A. R. C. Sharman; J. I. Hughes; K. Ridgway

2004-01-01

375

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

376

Smart Brackets for 3D-Force-Moment Measurements in Orthodontic Research and Therapy – Developmental Status and Prospects  

Microsoft Academic Search

Background and Aim:  Quantitative knowledge of the three-dimensional (3D) force-moment systems applied for therapeutic tooth movement is of utmost\\u000a importance, with regard to the predictability of the course of tooth movement, as well as the reduction of traumatic side\\u000a effects. The concept of a smart bracket with an integrated sensor system for 3D force and moment measurement has recently\\u000a been published.

Bernd G. Lapatki; Oliver Paul

2007-01-01

377

Assessment of clinical outcomes of Roth and MBT bracket prescription using the American Board of Orthodontics Objective Grading System  

PubMed Central

Background: There is always a need to assess whether small changes in bracket prescription can lead to visually detectable differences in tooth positions. However, with little clinical evidence to show advantages of any of the popularly used bracket systems, orthodontists are forced to make clinical decisions with little scientific guidance. Aim: To compare the orthodontic cases finished with Roth and MBT prescription using American Board of Orthodontics-Objective Grading System (ABO-OGS). Settings and Design: Department of Orthodontics, Post-graduate dental college, retrospective cross-sectional study. Materials and Methods: Forty patients selected were divided into two groups of 20 patients each finished with straight wire appliance using Roth and MBT prescription, respectively. The examiner ability was assessed and calibrated by one of the ABO certified clinician to grade cases using the OGS. Statistical Analysis: Unpaired student t-test was used and P < 0.05 was accepted as significant. Results and Conclusions: MBT bracket group had a lower score of 2.60 points in buccolingual inclination and lower score of 1.10 points in occlusal contact category that was statistically significant when compared with Roth group. The difference in total ABO-OGS score was 2.65 points showing that the outcome for the MBT prescription was better than that of the Roth prescription, which is statistically significant, but with little or no clinical significance. It can be concluded that use of either one of the Roth and MBT bracket prescriptions have no impact to the overall clinical outcome and quality of treatment entirely depends on clinician judgment and experience.

Jain, Mahesh; Varghese, Joseph; Mascarenhas, Rohan; Mogra, Subraya; Shetty, Siddarth; Dhakar, Nidhi

2013-01-01

378

Optimal Bond Trading with Personal Taxes: Implications for Bond Prices and Estimated Tax Brackets and Yield Curves  

Microsoft Academic Search

The assumption that bondholders follow either a buy-and-hold or a continuous realization trading policy, rather than the optimal trading policy,is at variance with reality and, as we demonstrate, may seriously bias the estimation of the yield curve and the implied tax bracket of the marginal investor. Tax considerations which govern a bondholder's optimal trading policy include the following: realization of

George M. Constantinides; Jonathan E. Ingersoll Jr.

1984-01-01

379

The use of Ormocer as an alternative material for bonding orthodontic brackets.  

PubMed

As new adhesives, composite resins, and bonding techniques were introduced, orthodontists adopted some of these innovations and added them to their armamentarium. The purpose of this study was to compare the shear bond strength (SBS) of two adhesive materials; one with an organically modified ceramic matrix, Admira (Voco, Cuxhaven, Germany) and another that contains the traditional Bis GMA matrix namely Transbond XT (3M Unitek, Monrovia, Calif). The new materials have a lower wear rate and are more biocompatible than traditional composites. Forty molar teeth were randomly divided into two groups: 20 teeth bonded with the Transbond adhesive system and the other 20 teeth with the Admira bonding system. Student's t-test was used to compare the SBS of the two adhesives. Significance was predetermined at P < or = .05. The results of the t-test comparisons (t = 0.489) of the SBS indicated that there was no significant (P = .628) difference between the two adhesives tested. The mean SBS for Admira was 5.1 +/- 3.3 MPa and that for Transbond XT was 4.6 +/- 3.2 MPa. It was concluded that the new material, Ormocer, which is an organically modified ceramic restorative material can potentially have orthodontic applications if available in a more flowable paste. These new materials are more biocompatible and have lower wear rate including bonding orthodontic brackets to teeth. PMID:15747824

Ajlouni, Raed; Bishara, Samir E; Soliman, Manal M; Oonsombat, Charuphan; Laffoon, John F; Warren, John

2005-01-01

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

Phase-locked loop based on machine surface topography measurement using lensed fibers  

SciTech Connect

We present the phase-locked loop (PLL)-based metrology concept using lensed fibers for on-machine surface topography measurement. The shape of a single-mode fiber at the endface was designed using an ABCD matrix method, and two designed lensed fibers--the ball type and the tapered type--were fabricated, and the performance was evaluated, respectively. As a result, the interferometric fringe was not found in the case of the ball lensed fiber, but the machined surface could be measured by utilization of autofocusing and intensity methods. On the other hand, a very clear Fizeau interferometric fringe was observed in the case of the tapered lensed fiber. Its performance was compared with the results of the capacitance sensor and a commercially available white-light interferometer. We confirmed that PLL-based surface profile measurement using the tapered and ball lensed fibers can be applied for on-machine surface topography measurement applications.

Kang, Jin-Ho; Lee, ChaBum; Joo, Jae-Young; Lee, Sun-Kyu

2011-02-01

382

Combinatorial density functional theory-based screening of surface alloys for the oxygen reduction reaction.  

SciTech Connect

A density functional theory (DFT) -based, combinatorial search for improved oxygen reduction reaction (ORR) catalysts is presented. A descriptor-based approach to estimate the ORR activity of binary surface alloys, wherein alloying occurs only in the surface layer, is described, and rigorous, potential-dependent computational tests of the stability of these alloys in aqueous, acidic environments are presented. These activity and stability criteria are applied to a database of DFT calculations on nearly 750 binary transition metal surface alloys; of these, many are predicted to be active for the ORR but, with few exceptions, they are found to be thermodynamically unstable in the acidic environments typical of low-temperature fuel cells. The results suggest that, absent other thermodynamic or kinetic mechanisms to stabilize the alloys, surface alloys are unlikely to serve as useful ORR catalysts over extended periods of operation.

Greeley, J.; Norskov, J.; Center for Nanoscale Materials; Technical Univ. of Denmark

2009-03-26

383

Soil state and surface hydrology diagnosis based on MOSES in the Met Office Nimrod nowcasting system  

NASA Astrophysics Data System (ADS)

A system has been developed and made operational at the Met Office for the real-time diagnosis of soil state and surface hydrology. It is based on the Met Office Surface Exchanges Scheme (MOSES) modified to take account of unresolved soil and topographic heterogeneity when calculating surface runoff by incorporating a Probability Distributed Moisture (PDM) scheme developed by the Centre for Ecology and Hydrology. The implementation of MOSES-PDM in the Met Office's Nimrod nowcasting system is described. High resolution soil characteristics and land cover data, together with Nimrod's analyses of precipitation amount and type, cloud cover and near-surface atmospheric variables are used to drive MOSES-PDM. Hourly values of snowmelt, runoff, net surface radiation, evaporation, potential evaporation, soil temperature, soil moisture and soil moisture deficit are calculated on a 5 km grid.

Smith, R. N. B.; Blyth, E. M.; Finch, J. W.; Goodchild, S.; Hall, R. L.; Madry, S.

384

A List-Based Method for Fast Generation of Molecular Surfaces  

PubMed Central

In this paper we present a fast and reliable method for generation of molecular surfaces. While the method is readily applicable to van der Waals surface generation, we shall be focusing on solvent-accessible surfaces (SAS) and solvent-excluded surfaces (SES) of a molecule. A list-based method is utilized to represent and generate the union of multiple spheres with arbitrary radii, with which we are able to produce the SAS and SES of a molecule in a very efficient way. The surface generated is represented by a quadrilateral mesh, which can be easily converted into a triangular mesh if needed. Some results will be provided to demonstrate the speed and quality of our mesh generation algorithms.

Yu, Zeyun

2010-01-01

385

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

386

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

2012-08-21

387

Construction of sliding constraint surfaces based on QP model in multi-step inverse analysis  

NASA Astrophysics Data System (ADS)

In this paper, the sliding constraint surfaces are automatically generated by a Pseudo-Minimum Area method (PMA), and the Initial Guess is generated on the constructed sliding constraint surface based on the One-step inverse approach. In the PMA method, the three-dimensional construction problem of sliding constraint surfaces was converted into a Quadratic Programming (QP) problem from the perspective of optimization. Since the high-efficiency solving of QP problems, the sliding constraint surfaces can be generated efficiently. Constructed sliding constraint surfaces and Initial guesses are applied to the multi-step drawing process. The numerical analysis result is compared with One-step inverse analysis and DYNAFORM to evaluate the effectiveness of the multi-step inverse analysis.

Liu, Weijie; Hu, Ping; Zhou, Ping; Zhang, Xiangkui

2013-05-01

388

3D surface reconstruction and panorama stitching based on LCD-based calibration and multi-baselines stereo matching  

Microsoft Academic Search

This paper presents an automatic method of 3D surface reconstruction and panorama stitching based on LCD-based calibration and multi-baselines stereo matching. In the method, calibration is carried out using a 2D control field composed by the completely flat liquid crystal display (LCD), on which lots of circle points with known coordinates are drawn by a simple program. Then, the technology

Zhan Zongqian; Zhang Xiaoqian

2009-01-01

389

Statistics of Antarctic surface meteorology based on hourly data in 1957–2007 at Syowa Station  

Microsoft Academic Search

Statistical characteristics of the surface meteorology are examined at Syowa Station (69°00?S, 39°35?E), which is located on an island near the coastal region of the Antarctic continent, based on operational observations made over the 50-year period from February 1957 through January 2007, which includes missing periods equivalent to 5 years. Statistics are obtained for the surface temperature, sea level pressure

Kaoru Sato; Naohiko Hirasawa

2007-01-01

390

RESIDUAL STRESS ASSESSMENT IN SURFACE-TREATED NICKEL-BASE SUPERALLOYS  

Microsoft Academic Search

Experimental results are presented to illustrate that there exists a unique window of opportunity for eddy current NDE of residual stress in surface-treated nickel-base superalloys. In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in surface-treated components. This technique is

M. P. Blodgett; P. B. Nagy

391

Effect of different surface treatments on tensile bond strength of silicone-based soft denture liner  

Microsoft Academic Search

Failure of the bond between the acrylic resin and resilient liner material is commonly encountered in clinical practice. The\\u000a purpose of this study was to investigate the effect of different surface treatments (sandblasting, Er:YAG, Nd:YAG, and KTP\\u000a lasers) on tensile bond strength of silicone-based soft denture liner. Polymethyl methacrylate test specimens were fabricated\\u000a and each received one of eight surface

Hakan Akin; Faik Tugut; Burcu Mutaf; Gulsah Akin; A. Kemal Ozdemir

392

Effect of grinding temperatures on the surface integrity of a nickel-based superalloy  

Microsoft Academic Search

An experimental study was carried out to investigate the influence of temperatures on workpiece surface integrity in the surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. The temperature response at the wheel–workpiece interface was measured using a grindable foil\\/workpiece thermocouple. Specimens with different grinding temperatures were obtained through changing the grinding conditions, including the depth of cut,

X. P Xu; Y. Q Yu; H. J Xu

2002-01-01

393

Scalability of the surface-based DNA algorithm for 3SAT  

Microsoft Academic Search

Since Adleman first proposed DNA computing for the Hamiltonian path problem, several authors have reported DNA computing for 3-SAT. Previous research presented DNA computing on surfaces and demonstrated how to solve a four-variable four-clause instance of 3-SAT, and claimed that the surface-based approach was designed to scale up to larger problems. In this paper we establish an error model for

Dafa Li; Xiangrong Li; Hongtao Huang; Xinxin Li

2006-01-01

394

Finite element based evaluation of stress intensity factors for interactive semi-elliptic surface cracks  

Microsoft Academic Search

A finite thickness plate with two coplanar self-same shallow and deep semi-elliptical surface cracks subjected to remote tensile surface traction is considered for fracture analysis. Based on three-dimensional (3D) finite element solutions, stress intensity factors (SIFs) are evaluated along the entire crack front using a force method. The line spring model has also been used to evaluate crack depth point

Raju Sethuraman; G. Siva Sankara Reddy; I. Thanga Ilango

2003-01-01

395

Acid–base chemistry of albite surfaces in aqueous solutions at standard temperature and pressure  

Microsoft Academic Search

Surface acidity of albite has been determined by potentiometric titration of water-washed and unwashed powders at 23.5°C and pH range of 2–9.5. Using NH4Cl as the background electrolyte the surface was titrated with HCl and NH4OH in both forward and backward directions. These titrants have the advantage of possessing the same acid- and base-radicals as those of the background electrolyte

Biswajit Mukhopadhyay; John V. Walther

2001-01-01

396

Characteristics of thin surface layers of cobalt-based alloys deposited by laser cladding  

Microsoft Academic Search

Thin surface layers of cobalt-based alloys (Stellite 6 and Tribaloy T-900) and 410 stainless steel (SS) were deposited on mild steel substrates by a coaxial laser cladding process. This process could produce a thin surface layer of less than 0.5 mm with low energy input. Laser-clad Stellite 6 and Tribaloy T-900 specimens exhibited refined dendritic microstructure. The interdendritic eutectics consisted

W. C. Lin; C. Chen

2006-01-01

397

Sensitive and selective chem\\/bio sensing based on surface-enhanced Raman spectroscopy (SERS)  

Microsoft Academic Search

This paper summarizes our recent progress toward developing anthrax and glucose sensors based on surface-enhanced Raman spectroscopy (SERS). Ag film over nanosphere (AgFON) substrates was used as the SERS sensor platform in both cases. The AgFON substrates have been optimized for near-infrared (NIR) laser excitations by tuning the extinction maximum of their localized surface plasmon resonance (LSPR). Bacillus subtilis spores,

Xiaoyu Zhang; Nilam C. Shah; Richard P. Van Duyne

2006-01-01

398

Ultraviolet Detectors Based on Ultraviolet--Ozone Modified Hydrogenated Diamond Surfaces  

Microsoft Academic Search

Photodetectors based on interdigitated fingers have been fabricated on hydrogen terminated diamond surfaces. These devices show weak photocurrent-to-dark current ratio (PDR˜ 10-2) and persistent photoconductivity making them inappropriate for ultraviolet (UV) detection applications despite high deep UV photocurrent (˜10-4 A) and a spectral discrimination ratio (210\\/630 nm) of 105. However, an original approach combining the previous hydrogen terminated diamond surface

Jose Alvarez; Meiyong Liao; Jean-Paul Kleider; Yasuo Koide; Masataka Imura

2009-01-01

399

Photocurrent and Surface Photovoltage Spectroscopy Investigations of CdTe-based Compounds  

Microsoft Academic Search

The potentiality of photocurrent (PC) and surface photovoltage spectrosocopy (SPS) analyses in the determination of the band gap of CdTe-based ternary alloys was investigated. Both methods can detect band-to-band and defect state-to-band transitions. The role played by the surface states in both experimental methods has been studied since it may significantly alter the results. The below-band gap energy levels have

Anna Cavallini; Daniela Cavalcoli; Antonio Castaldini; Beatrice Fraboni

2006-01-01

400

Rapid detection of DNA hybridization on surface plasmon resonance based microarrays  

Microsoft Academic Search

The detection of DNA hybridization in medical diagnostics ought to be rapid, sensitive and specific. A platform technology based on surface plasmon resonance (SPR) is presented. We use TOPAS® chips with integrated optics and combined with microfluidics. Applying a nanoliter dispenser, thiol-modified single-stranded probe DNA (anti-tag) is deposited on the gold surface of the chips to create a DNA microarray.

Alfred Kick; M. Bo?nsch; M. Mertig; A. Herr; W. Brabetz; M. Jung; F. Sonntag

2010-01-01

401

Empirical Copula Driven Hand Motion Recognition via Surface Electromyography Based Templates  

Microsoft Academic Search

\\u000a Current tendency of electromyography (EMG) based prosthetic hand is to enable the user to perform complex grasps or manipulations\\u000a with natural muscle movements. In this paper, a new classifier is introduced to identify the naturally contracted surface\\u000a EMG patterns for hand motion recognition. The recognition method utilizes a dependence structure as a motion template, which\\u000a includes one-to-one correlations of surface

Zhaojie Ju; Honghai Liu

2010-01-01

402

A Physically Based Accurate Model for Quantum Mechanical Correction to the Surface Potential of Nanoscale MOSFETs  

Microsoft Academic Search

We present a physically based explicit analytical model for the quantum mechanical (QM) correction to the surface potential of nanoscale metal-oxide-semiconductor (MOS) devices. The effect of wave function penetration into the gate dielectric is taken into account. Instead of using the band-gap widening approach, which indirectly includes QM correction, the proposed correction term is directly added to the semiclassical surface

M. A. Karim; Anisul Haque

2010-01-01

403

Microscale fabrication and characterization of a silver-polymer-based electrically activated antibacterial surface  

Microsoft Academic Search

This paper reports the fabrication methodology and characterization results for an electrically activated silver-polymer-based antibacterial surface with primary applications in preventing indirect contact transmission of infections. The surface consists of a micro-scale grating pattern of alternate silver electrodes and SU-8 partitions with a minimum feature size of 20 µm, and activated by an external voltage. In this study, prototype coupons

Rohan A. Shirwaiker; Richard A. Wysk; Subhashinie Kariyawasam; Hector Carrion; Robert C. Voigt

2011-01-01

404

A method for testing drag-reduction on riblet surfaces based on the Spalding formula  

Microsoft Academic Search

This paper presents a method based on the Spalding formula for testing drag-reduction on riblet surfaces. Its advantage lies\\u000a in that it is more convenient and yields more precise data compared with testing methods using instruments such as a scale.\\u000a With this method, data is obtained from the velocity distribution within the inner layer, nearest the riblet surface. Precision\\u000a of

Bao-Wei Song; Zhan-Yi Liu; Ting Xu; Hai-Bao Hu; Ming-Ming Huang

2009-01-01

405

A method for testing drag-reduction on riblet surfaces based on the Spalding formula  

NASA Astrophysics Data System (ADS)

This paper presents a method based on the Spalding formula for testing drag-reduction on riblet surfaces. Its advantage lies in that it is more convenient and yields more precise data compared with testing methods using instruments such as a scale. With this method, data is obtained from the velocity distribution within the inner layer, nearest the riblet surface. Precision of measurement of the velocity distribution is the key factor affecting the precision of the testing.

Song, Bao-Wei; Liu, Zhan-Yi; Xu, Ting; Hu, Hai-Bao; Huang, Ming-Ming

2009-12-01

406

Non-linear surface wave phase velocity inversion based on ray theory  

Microsoft Academic Search

The development of temporary and permanent broad-band seismic arrays reinforces the need for advanced interpretation techniques in surface-wave analysis. We present a new method based on 2-D paraxial ray theory of inverting teleseismic surface-wave phase information and constructing phase velocity maps on a regional scale. Measurements of local phase velocities and propagation directions of Rayleigh waves taken from full waveform

Marianne Bruneton; Véronique Farra; Helle Anette Pedersen

2002-01-01

407

Physics-based mathematical conditioning of the MOSFET surface potential equation  

Microsoft Academic Search

The traditional form of the implicit equation for the surface potential (?s) in metal-oxide-semiconductor field-effect transistors (MOSFETs) works well except near the flatband point ?s=0 where it is both unphysical and ill-conditioned mathematically. This represents a significant difficulty for recent surface potential-based models, which require ?s evaluation from the accumulation to the strong inversion region. Detailed physical analysis combined with

Weimin Wu; Ten-Lon Chen; Gennady Gildenblat; Colin C. McAndrew

2004-01-01

408

Probing the Photothermal Effect of Au-Based Nanocages with Surface-Enhanced Raman Scattering (SERS)**  

PubMed Central

A SERS-based thermometer for the photothermal effect The conformation of molecules on a metallic nanoparticle’s surface is sensitive to temperature variations and can be easily monitored in situ by SERS. Excitation of the metallic nanoparticle for SERS can concurrently induce a photothermal effect whereby the light absorbed by the nanoparticle is released as heat. From the SERS spectra, we could derive the changes in temperature at the surface of a nanoparticle during the photothermal effect.

Rycenga, Matthew; Wang, Zhipeng; Gordon, Eric; Cobley, Claire M.; Schwartz, Andrea G.; Lo, Cynthia S.

2010-01-01

409

Surface plasmon resonance sensor for domoic acid based on grafted imprinted polymer  

Microsoft Academic Search

A molecularly imprinted polymer (MIP) film for domoic acid (DA) was synthesised by direct photo-grafting onto a gold chip suitable for a surface plasmon resonance (SPR) based bioanalytical instrument system, the BIAcore 3000™. The gold surface was first functionalised with a self-assembled monolayer of 2-mercaptoethylamine and subsequent carbodiimide chemistry was performed for covalent attachment of the photoinitiator, 4,4?-azobis(cyanovaleric acid). This

M. Lotierzo; O. Y. F. Henry; S. Piletsky; I. Tothill; D. Cullen; M. Kania; B. Hock; A. P. F Turner

2004-01-01

410

Superhydrophobic Zr-based metallic glass surface with high adhesive force  

NASA Astrophysics Data System (ADS)

Micro/nano hierarchical structures were constructed on Zr35Ti30Be26.75Cu8.25 metallic glass surface by silicon moulding and subsequently chemical etching. The as-formed surface exhibited both superhydrophobicity and high adhesive force towards water. The superhydrophobicity is rationalized based on the modified Cassie-Baxter model [A. B. D. Cassie and S. Baxter, Trans. Faraday Soc. 40, 546 (1944)]. The origin of the robust adhesion is described in terms of intermolecular capillary forces. The present results not only provide a method to fabricate superhydrophobic metallic glasses surface but also explore an important industrial application as dry adhesives and transport of liquid microdroplets.

Li, Ning; Xia, Ting; Heng, Liping; Liu, Lin

2013-06-01

411

Automatic Cortical Sulcal Parcellation Based on Surface Principal Direction Flow Field Tracking  

PubMed Central

The human cerebral cortex is a highly convoluted structure composed of sulci and gyri, corresponding to the valleys and ridges of the cortical surface respectively. Automatic parcellation of the cortical surface into sulcal regions is of great importance in structural and functional mapping of the human brain. In this paper, a novel method is proposed for automatic cortical sulcal parcellation based on the geometric characteristics of cortical surface including its principal curvatures and principal directions. This method is composed of two major steps: 1) employing the hidden Markov random field model (HMRF) and the expectation maximization (EM) algorithm on the maximum principal curvatures of the cortical surface for sulcal region segmentation, and 2) using a principal direction flow field tracking method on the cortical surface for sulcal basin segmentation. The flow field is obtained by diffusing the principal direction field on the cortical surface mesh. A unique feature of this method is that the automatic sulcal parcellation process is quite robust and efficient, and is independent of any external guidance such as atlas-based warping. The method has been successfully applied to the inner cortical surfaces of twelve healthy human brain MR images. Both quantitative and qualitative evaluation results demonstrate the validity and efficiency of the proposed method.

Li, Gang; Guo, Lei; Nie, Jingxin; Liu, Tianming

2009-01-01

412

Surface changes induced by fluoride prophylactic agents on titanium-based orthodontic wires.  

PubMed

This study investigated the effect of fluoride prophylactic agents on the surfaces of titanium-based orthodontic wires. Four types of titanium-based orthodontic wires (2 nickel-titanium alloy wires [nickel-titanium and copper-nickel-titanium] and 2 beta-titanium alloy wires [titanium-molybdenum and titanium-niobium], all from Ormco, Glendora, Calif) with similar sizes were prepared and immersed in 5 fluoride prophylactic agents (2 acidulated phosphate fluoride agents [Nupro APF (Dentsply International, York, Pa) and Florentine III (Confi-Dental, Louisville, Colo)], 1 neutral agent [Neupro Neutral (Dentsply International)] and 2 stannous fluoride agents [Florentine II (Confi-Dental) and Perio-Med (Omni International, Warrenton, Va)]) for 5 minutes, 1 hour, and 24 hours. After immersion, average surface roughness and color changes were evaluated. The surface changes were observed with a scanning electron microscope. The average surface roughness data were statistically analyzed by analysis of variance and Tukey post hoc test at a significance level of alpha = 0.05. There were no significant differences in average surface roughness value among fluoride solutions or orthodontic wires, except for the titanium-molybdenum wire, which showed significantly (P <.05) higher average surface roughness values after immersion in Nupro APF for 24 hours. The results suggested that a few applications of acidulated phosphate fluoride agents might change the surface color of the beta-titanium alloy wires, particularly the titanium-molybdenum wire, which contains a large amount (about 80%) of titanium. PMID:12806345

Watanabe, Ikuya; Watanabe, Etsuko

2003-06-01

413

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

414

Development of a laser-scattering-based probe for on-line measurement of surface roughness.  

PubMed

The design and properties of an optical probe for on-line measurement of surface roughness are discussed. Based on light scattering, a probe that consists of a laser diode, a measuring lens, and a linear photodiode array was designed to detect surface roughness, in which the light scattered from a test surface at a relatively large scattering angle phi (=28 degrees) can be collected to enhance measuring range and repeatability. A coaxial design that incorporates a dual-laser probe and compressed air makes the proposed system insensitive to the position of the test surface and to surface conditions such as the presence of debris, vibration, and lubricants that result from machining. The results from measurements of several sets of specimens have demonstrated the feasibility of measuring surface roughness by using light scattering. On-line measurement on a diamond-turning lathe has shown that the proposed technique is stable and compact enough to be applicable to on-line measurement of surface roughness of an engineering surface. PMID:12638888

Wang, Shihua; Tian, Yunhui; Tay, Cho Jui; Quan, Chenggen

2003-03-01

415

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

416

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

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

417

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

PubMed Central

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.

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

2010-01-01

418

GaN-based high contrast grating surface-emitting lasers  

NASA Astrophysics Data System (ADS)

GaN-based high contrast grating surface-emitting lasers (HCG SELs) with AlN/GaN distributed Bragg reflectors were reported. The device exhibited a low threshold pumping energy density of about 0.56 mJ/cm2 and the lasing wavelength was at 393.6 nm with a high degree of polarization of 73% at room temperature. The specific lasing mode and polarization characterisitcs agreed well with the theoretical modeling. The low threshold characteristics of our GaN-based HCG SELs faciliated by the Fano resonance can serve as the best candidate in blue surface emitting laser sources.

Wu, Tzeng-Tsong; Wu, Shu-Hsien; Lu, Tien-Chang; Wang, Shing-Chung

2013-02-01

419

Model-based RSA of a femoral hip stem using surface and geometrical shape models.  

PubMed

Roentgen stereophotogrammetry (RSA) is a highly accurate three-dimensional measuring technique for assessing micromotion of orthopaedic implants. A drawback is that markers have to be attached to the implant. Model-based techniques have been developed to prevent using special marked implants. We compared two model-based RSA methods with standard marker-based RSA techniques. The first model-based RSA method used surface models, and the second method used elementary geometrical shape (EGS) models. We used a commercially available stem to perform experiments with a phantom as well as reanalysis of patient RSA radiographs. The data from the phantom experiment indicated the accuracy and precision of the elementary geometrical shape model-based RSA method is equal to marker-based RSA. For model-based RSA using surface models, the accuracy is equal to the accuracy of marker-based RSA, but its precision is worse. We found no difference in accuracy and precision between the two model-based RSA techniques in clinical data. For this particular hip stem, EGS model-based RSA is a good alternative for marker-based RSA. PMID:16826102

Kaptein, Bart L; Valstar, Edward R; Spoor, Cees W; Stoel, Berend C; Rozing, Piet M

2006-07-01

420

A test of the validity of range of motion studies of fossil archosaur elbow mobility using repeated-measures analysis and the extant phylogenetic bracket.  

PubMed

Recent studies have presented range of motion (ROM) data in degrees for dinosaur forelimb joints, usually via physical manipulation of one individual. Using these data, researchers have inferred limb orientations, postures, gaits, ecological functions and even phylogenetic trends within clades. However, important areas of concern remain unaddressed; for example, how does ROM at a forelimb joint change after soft tissues are lost in archosaurs? And are fossil ROM methodologies amenable to reproducibility and statistical analysis? Here, we investigated these questions using the extant phylogenetic bracket of dinosaurs. Repeated measures of elbow joint ROM from Struthio camelus and Alligator mississippiensis forelimbs were statistically analyzed as they were sequentially dissected through five levels of tissue removal treatment. Our data indicate that there are no statistically significant differences in repeated measures of ROM between observers who use the same techniques. Extrinsic soft tissues, such as integument, muscles and ligaments were found to impede ROM at the elbow joint. Intrinsic soft tissues, such as articular cartilage, may increase ROM. The hypothesis that the articular surfaces of the bones within the elbow joints of archosaurs provide a general approximation of mobility is supported. Final ROMs were less than the initial ROMs in both taxa, which suggests that prior reports of elbow joint ROMs in degrees for nonavian dinosaurs may represent conservative estimates. We conclude that if observer bias and other variables are controlled for, ROM studies of fossil archosaur limbs can obtain useful degree data for inferring joint mobility in vivo. PMID:22623191

Hutson, Joel D; Hutson, Kelda N

2012-06-15

421

Surface Energy Fluxes on the Great Lakes Based on Satellite-Observed Surface Temperatures 1992 to 1995  

Microsoft Academic Search

Accurate estimates of surface energy exchange components are critical for understanding many physical processes of large lakes and their atmospheric environment. In this paper, the seasonal cycle of latent, sensible, and total heat flux from the surface of the Great Lakes is estimated. Lake surface temperatures derived from the NOAA\\/AVHRR satellite, along with meteorological data from surface station observations are

Brent M. Lofgren; Yongchun Zhu

2000-01-01

422

Analyzing the footprints of near-surface aqueous turbulence: An image processing-based approach  

NASA Astrophysics Data System (ADS)

Abstract In this contribution, a detailed investigation of <span class="hlt">surface</span> thermal patterns on the water <span class="hlt">surface</span> is presented, with wind speeds ranging from 1 to 7 m s - 1 and various <span class="hlt">surface</span> conditions. Distinct structures can be observed on the <span class="hlt">surface</span>—small-scale short-lived structures termed fish scales and larger-scale cold streaks that are consistent with the footprints of Langmuir circulations. The structure of the <span class="hlt">surface</span> heat pattern depends strongly on wind-induced stress. Consistent behavior regarding the spacing of cold streaks can be observed in a range of laboratory facilities when expressed as a function of water-sided friction velocity, u * . This behavior systematically decreased until a point of saturation at u * = 0.7 cm/s. We present a new image processing-<span class="hlt">based</span> approach to the analysis of the spacing of cold streaks <span class="hlt">based</span> on a machine learning approach to classify the thermal footprints of near-<span class="hlt">surface</span> turbulence. Comparison is made with studies of Langmuir circulation and the following key points are found. Results suggest a saturation in the tangential stress, anticipating that similar behavior will be observed in the open ocean. A relation to Langmuir numbers shows that thermal footprints in infrared images are consistent with Langmuir circulations and depend strongly on wind wave conditions.</p> <div class="credits"> <p class="dwt_author">Schnieders, J.; Garbe, C. S.; Peirson, W. L.; Smith, G. B.; Zappa, C. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">423</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3432236"> <span id="translatedtitle">Parcellations and Hemispheric Asymmetries of Human Cerebral Cortex Analyzed on <span class="hlt">Surface-Based</span> Atlases</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">We report on <span class="hlt">surface-based</span> analyses that enhance our understanding of human cortical organization, including its convolutions and its parcellation into many distinct areas. The <span class="hlt">surface</span> area of human neocortex averages 973 cm2 per hemisphere, <span class="hlt">based</span> on cortical midthickness <span class="hlt">surfaces</span> of 2 cohorts of subjects. We implemented a method to register individual subjects to a hybrid version of the FreeSurfer “fsaverage” atlas whose left and right hemispheres are in precise geographic correspondence. Cortical folding patterns in the resultant population-average “fs_LR” midthickness <span class="hlt">surfaces</span> are remarkably similar in the left and right hemispheres, even in regions showing significant asymmetry in 3D position. Both hemispheres are equal in average <span class="hlt">surface</span> area, but hotspots of <span class="hlt">surface</span> area asymmetry are present in the Sylvian Fissure and elsewhere, together with a broad pattern of asymmetries that are significant though small in magnitude. Multiple cortical parcellation schemes registered to the human atlas provide valuable reference data sets for comparisons with other studies. Identified cortical areas vary in size by more than 2 orders of magnitude. The total number of human neocortical areas is estimated to be ?150 to 200 areas per hemisphere, which is modestly larger than a recent estimate for the macaque.</p> <div class="credits"> <p class="dwt_author">Glasser, Matthew F.; Dierker, Donna L.; Harwell, John; Coalson, Timothy</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">424</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JChPh.137a4703F"> <span id="translatedtitle">Origin of synergistic effect over Ni-<span class="hlt">based</span> bimetallic <span class="hlt">surfaces</span>: A density functional theory study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Density functional theory calculations have been conducted to explore the physical origin of the synergistic effect over Ni-<span class="hlt">based</span> <span class="hlt">surface</span> alloys using methane dissociation as a probe reaction. Some late transition metal atoms (M = Cu, Ru, Rh, Pd, Ag, Pt, and Au) are substituted for <span class="hlt">surface</span> Ni atoms to examine the variation in electronic structure and adsorption property of Ni(111). Two types of threefold hollow sites, namely, the Ni2M and Ni3 sites, are taken into account. The calculated results indicate that the variation in the CHx adsorption energy at the Ni2M and Ni3 sites is dominated by the ensemble and ligand effect, respectively, and the other factors such as <span class="hlt">surface</span> and adsorbate distortion and electrostatic interaction affect the catalytic properties of the bimetallic <span class="hlt">surfaces</span> to a smaller extent. Both the Brønsted-Evans-Polanyi relationship and the scaling correlation hold true on the Ni-<span class="hlt">based</span> bimetallic <span class="hlt">surfaces</span>. With the combination of these two linear energy relations, the corrected binding energy of atomic C is found to be a good descriptor for representing the catalytic activity of the alloyed <span class="hlt">surfaces</span>. Considering the compromise between the catalytic activity and catalyst stability, we suggest that the Rh/Ni catalyst is a good candidate for methane dissociation.</p> <div class="credits"> <p class="dwt_author">Fan, Chen; Zhu, Yi-An; Xu, Yue; Zhou, Yan; Zhou, Xing-Gui; Chen, De</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">425</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23755737"> <span id="translatedtitle">Comprehensive structural, <span class="hlt">surface</span>-chemical and electrochemical characterization of nickel-<span class="hlt">based</span> metallic foams.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Nickel-<span class="hlt">based</span> metallic foams are commonly used in electrochemical energy storage devices (rechargeable batteries) as both current collectors and active mass support. These materials attract attention as tunable electrode materials because they are available in a range of chemical compositions, pore structures, pore sizes, and densities. This contribution presents structural, chemical, and electrochemical characterization of Ni-<span class="hlt">based</span> metallic foams. Several materials and <span class="hlt">surface</span> science techniques (transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), focused ion beam (FIB), and X-ray photoelectron spectroscopy (XPS)) and electrochemical methods (cyclic voltammetry (CV)) are used to examine the micro-, meso-, and nanoscopic structural characteristics, <span class="hlt">surface</span> morphology, and <span class="hlt">surface</span>-chemical composition of these materials. XPS combined with Ar-ion etching is employed to analyze the <span class="hlt">surface</span> and near-<span class="hlt">surface</span> chemical composition of the foams. The specific and electrochemically active <span class="hlt">surface</span> areas (As, Aecsa) are determined using CV. Though the foams exhibit structural robustness typical of bulk materials, they have large As, in the range of 200-600 cm(2) g(-1). In addition, they are dual-porosity materials and possess both macro- and mesopores. PMID:23755737</p> <div class="credits"> <p class="dwt_author">van Drunen, Julia; Kinkead, Brandy; Wang, Michael C P; Sourty, Erwan; Gates, Byron D; Jerkiewicz, Gregory</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-06-24</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">426</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21206160"> <span id="translatedtitle">Evaluating <span class="hlt">surface</span> roughness of a polyamide denture <span class="hlt">base</span> material in comparison with poly (methyl methacrylate).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Polyamide denture <span class="hlt">base</span> materials are more flexible than the commonly used poly (methyl methacrylate) (PMMA). However polishability of polyamides has not been examined adequately. This study investigated the <span class="hlt">surface</span> roughness (Ra) and clinical acceptability of samples of a polyamide denture <span class="hlt">base</span> material and PMMA fabricated by injection moulding and traditional heat processing systems, respectively. Half of each sample <span class="hlt">surface</span> was polished using the conventional technique (lathe with pumice followed by high shine buffs) and the other half was left unpolished. A profilometer was used to measure Ra along 3 tracks on each <span class="hlt">surface</span> before and after polishing. Two-way ANOVA was used to compare the two <span class="hlt">surfaces</span> of the two materials for variations in Ra values. Polyamide denture <span class="hlt">base</span> material when polished with conventional laboratory technique became more than 7 times smoother whereas processed PMMA when polished became more than 20 times smoother using the same polishing technique. However the <span class="hlt">surface</span> roughness of polyamide is well within the accepted norm of 0.2 µm Ra. Polyamide produces a clinically acceptable smoothness after conventional polishing by lathe. PMID:21206160</p> <div class="credits"> <p class="dwt_author">Abuzar, Menaka A; Bellur, Suman; Duong, Nancy; Kim, Billy B; Lu, Priscilla; Palfreyman, Nick; Surendran, Dharshan; Tran, Vinh T</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">427</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGRD..118..577H"> <span id="translatedtitle">Enhancing model-<span class="hlt">based</span> land <span class="hlt">surface</span> temperature estimates using multiplatform microwave observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Land <span class="hlt">surface</span> temperature plays an important role in <span class="hlt">surface</span> processes and is a key input for physically <span class="hlt">based</span> retrieval algorithms of soil moisture and evaporation. This study presents a framework for using independent estimates of land <span class="hlt">surface</span> temperature from five microwave satellite sensors to improve the accuracy of land <span class="hlt">surface</span> temperature output from a numerical weather prediction system in an off-line (postprocessing) analysis. First, structural differences in timing and amplitude of the temperature signal were addressed. Then, satellite observations were assimilated into an auto-regressive error model, formulated to estimate errors in the numerical weather prediction output. Errors in daily minimum and amplitude were treated separately. Results of this study provide new insights about potential added benefits of preprocessing and off-line assimilation of microwave remote sensing-<span class="hlt">based</span> and model-<span class="hlt">based</span> temperature retrievals. It is shown that the satellite observations may be used to reduce errors in <span class="hlt">surface</span> temperature, particularly for day-time hours. Preprocessing is responsible for the bulk of this reduction in temperature error; data assimilation is shown to further reduce the random temperature error by a few tenths of a Kelvin, accounting for a 10% reduction in RMSE.</p> <div class="credits"> <p class="dwt_author">Holmes, Thomas R. H.; Crow, Wade T.; Tugrul Yilmaz, M.; Jackson, Thomas J.; Basara, Jeffrey B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3182401"> <span id="translatedtitle">Single-Molecule Force Spectroscopy of DNA-<span class="hlt">Based</span> Reversible Polymer Bridges: <span class="hlt">Surface</span> Robustness and Homogeneity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Single-molecule force spectroscopy, as implemented in an atomic force microscope, provides a rarely-used method by which to monitor dynamic processes that occur near <span class="hlt">surfaces</span>. Here, a methodology is presented and characterized that facilitates the study of polymer bridging across nanometer-sized gaps. The model system employed is that of DNA-<span class="hlt">based</span> reversible polymers, and an automated procedure is introduced that allows the AFM tip-<span class="hlt">surface</span> contact point to be automatically determined, and the distance d between opposing <span class="hlt">surfaces</span> to be actively controlled. Using this methodology, the importance of several experimental parameters was systematically studied, e.g. the frequency of repeated tip/<span class="hlt">surface</span> contacts, the area of the substrate <span class="hlt">surface</span> sampled by the AFM, and the use of multiple AFM tips and substrates. Experiments revealed the <span class="hlt">surfaces</span> to be robust throughout pulling experiments, so that multiple touches and pulls could be carried out on a single spot with no measurable affect on the results. Differences in observed bridging probabilities were observed, both on different spots on the same <span class="hlt">surface</span> and, more dramatically, from one day to another. Data normalization via a reference measurement allows data from multiple days to be directly compared.</p> <div class="credits"> <p class="dwt_author">Serpe, Michael J.; Whitehead, Jason R.; Rivera, Monica; Clark, Robert L.; Craig, Stephen L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012OptEn..51k3605A"> <span id="translatedtitle">Feature extraction <span class="hlt">based</span> on contourlet transform and its application to <span class="hlt">surface</span> inspection of metals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Surface</span> defects that affect the quality of metals are an important factor. Machine vision systems commonly perform <span class="hlt">surface</span> 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 <span class="hlt">based</span> on contourlet transform and kernel locality preserving projections is proposed to extract sufficient and effective features from metal <span class="hlt">surface</span> 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 <span class="hlt">surfaces</span> 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 <span class="hlt">surface</span> defect databases from industrial <span class="hlt">surface</span>-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 <span class="hlt">surface</span> defects of continuous casting slabs and aluminum strips are up to 93.55% and 92.5%, respectively.</p> <div class="credits"> <p class="dwt_author">Ai, Yonghao; Xu, Ke</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21513138"> <span id="translatedtitle">Simultaneous Sterilization With <span class="hlt">Surface</span> Modification Of Plastic Bottle By Plasma-<span class="hlt">Based</span> Ion Implantation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Dry sterilization of polymeric material is developed. The technique utilizes the plasma-<span class="hlt">based</span> ion implantation which is same as for <span class="hlt">surface</span> 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 <span class="hlt">surface</span> modification enhanced the gas barrier characteristics of plastic bottles. Comparing the implantation conditions for the sterilization experiment with those for the <span class="hlt">surface</span> modification, we find that both sterilization and <span class="hlt">surface</span> 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.</p> <div class="credits"> <p class="dwt_author">Sakudo, N.; Ikenaga, N.; Ikeda, F.; Nakayama, Y.; Kishi, Y.; Yajima, Z. [Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838 (Japan)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">431</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012SPIE.8417E..07X"> <span id="translatedtitle">3D detection technique of <span class="hlt">surface</span> defects for heavy rail <span class="hlt">based</span> on binocular stereo vision</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The large number of scales on steel rails makes it impossible to apply traditional 2-D vision techniques to <span class="hlt">surface</span> inspection of steel rails. A 3-D detection technique <span class="hlt">based</span> on binocular stereo vision was developed to detect <span class="hlt">surface</span> defects of steel rails. Laser stripes emitted by linear lasers were projected on the <span class="hlt">surface</span> of steel rails, and images of laser lines were captured synchronously with two CCD cameras. Standard curves on heavy rails were obtained by adopting segment fitting method. Depth of the defects was calculated by matching points which were obtained respectively from the deepest defect point and its corresponding point on the standard curve. The examination showed that the error of the defect depth with the technique is 3.5%, and it is insensitive to vibration of steel rails during production. Thus the technique is applicable to on-line <span class="hlt">surface</span> inspection of steel rails.</p> <div class="credits"> <p class="dwt_author">Xu, Ke; Zhou, Peng; Hu, Chaofan</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">432</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008SPIE.7127E..50Y"> <span id="translatedtitle"><span class="hlt">Surface</span> smoothness detection algorithm <span class="hlt">based</span> on two-dimensional wavelet and computer vision</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This work proposes an algorithm to measure the smoothness of three-dimensional object. Firstly use computer vision technology to reconstruct the three-dimensional <span class="hlt">surface</span>. Then construct high order vanishing moment wavelet to analyze the data. In order to detect the discontinuous derivative points, this paper proposes an algorithm <span class="hlt">based</span> on wavelet transform. Wavelet is used to descript <span class="hlt">surface</span> smoothness and detect abnormal data. When using different vanishing moment wavelets to deal with data, we would get different value at those points with different smoothness value. That <span class="hlt">surface</span> with same smoothness would become a plane. Meanwhile, in order to improve the algorithm validity, this paper proposes using Daubechies wavelet. This algorithm resolved our project problem. It can be used in other projects that require the <span class="hlt">surface</span> with good smoothness.</p> <div class="credits"> <p class="dwt_author">Yang, Jian; Lu, Nai-Guang; Dong, Mingli</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">433</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010SPIE.7849E..36W"> <span id="translatedtitle">White light interferometry for fast areal <span class="hlt">surface</span> measurement <span class="hlt">based</span> on GPGPU</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">White-light interferometry is always an extremely useful and powerful tool for optical <span class="hlt">surface</span> measurement. In this paper, a novelty method <span class="hlt">based</span> on rapid positioning and fast <span class="hlt">surface</span> measurement is proposed. The adjustment of optical path difference (OPD) is done automatically by a wavelength scanning method, and the processing of white-light interference patterns is accelerated by GPGPU which stands for General-Purpose computation on Graphics Processing Units, also known as GPU Computing. Graphics Processing Units are high-performance many-core processors in which the data are processed in parallel. As a result, the time we need to obtain a <span class="hlt">surface</span> shape is reduced to ten percents compared with the conventional white-light interferometry. With these advantages, it is possible to measure a rough and areal <span class="hlt">surface</span> in a short time.</p> <div class="credits"> <p class="dwt_author">Wang, Jing; Wang, Kaiwei; Zhao, Shuangshuang; Lin, Li; Bai, Jian</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">434</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24041089"> <span id="translatedtitle">Nanopore <span class="hlt">Surface</span> Coating Delivers Nanopore Size and Shape through Conductance-<span class="hlt">Based</span> Sizing.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The performance of nanopore single-molecule sensing elements depends intimately on their physical dimensions and <span class="hlt">surface</span> chemical properties. These factors underpin the dependence of the nanopore ionic conductance on electrolyte concentration, yet the measured, or modeled, dependence only partially illuminates the details of geometry and <span class="hlt">surface</span> chemistry. Using the electrolyte-dependent conductance data before and after selective <span class="hlt">surface</span> functionalization of solid-state nanopores, however, introduces more degrees of freedom and improves the performance of conductance-<span class="hlt">based</span> nanopore characterizations. Sets of representative nanopore profiles were used to generate conductance data, and the nanopore shape and exact dimensions were identified, through conductance alone, by orders-of-magnitude reductions in the geometry optimization metrics. The optimization framework could similarly be used to evaluate the nanopore <span class="hlt">surface</span> coating thickness. PMID:24041089</p> <div class="credits"> <p class="dwt_author">Frament, Cameron M; Bandara, Nuwan; Dwyer, Jason R</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">435</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013SPIE.8791E..1IG"> <span id="translatedtitle">Automatic area <span class="hlt">based</span> registration method and its application to the <span class="hlt">surface</span> inspection of steel industry products</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We describe the automated application of an area <span class="hlt">based</span> registration method to the <span class="hlt">surface</span> inspection of steel industry products as a tool to solve an intermediate mosaicing problem. The main problem of area <span class="hlt">based</span> methods is that there is high probability that the results of a matching process will be incorrect if a region of interest without any relevant detail is used. The selection of a region of interest with relevant content continues to be a problem nowadays. We propose a method to select a salient area when using a zero mean normalised cross correlation metric and a block as a region of interest. The selection of the size and the position of the block is focused on ensuring a smooth unimodal similarity <span class="hlt">surface</span> around the maximum similitude point. Experiments show a correlation between the <span class="hlt">surface</span> kurtosis of the block autocovariance and the same coefficient measured over the correlation <span class="hlt">surface</span> around the maximum similitude point for the three different steel products analysed. We check that the maximum correlation value is reached abruptly, in a small range of pixels around the maximum similitude point, in correlation <span class="hlt">surfaces</span> obtained from blocks containing non-relevant information. On the other hand, salient blocks usually lead to unimodal smooth similarity <span class="hlt">surfaces</span> with small sensitivity to noise in contrast with the ones obtained from non-remarkable blocks. Also, the method proposed allows the application of fast search algorithms <span class="hlt">based</span> on the unimodality of the correlation <span class="hlt">surface</span>, obtaining high computational time reduction in comparison with full search strategies using fast normalised cross correlation algorithms.</p> <div class="credits"> <p class="dwt_author">García Llenderrozos, Ricardo; Álvarez García, Ignacio; Enguita González, José M.; Rodríguez Jiménez, Silvia</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">436</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16342503"> <span id="translatedtitle">A 3-d <span class="hlt">surface</span> reconstruction approach <span class="hlt">based</span> on postnonlinear ICA model.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Photometric stereo technique deals with the reconstruction of three-dimensional (3-D) shape of an object by using several images of the same <span class="hlt">surface</span> taken from the same viewpoint but under illuminations from different directions. In this paper, we propose a new photometric stereo scheme <span class="hlt">based</span> on a new reflectance model and the postnonlinear (PNL) independent components analysis (ICA) method. The proposed nonlinear reflectance model consists of diffuse components and specular components for modeling the <span class="hlt">surface</span> reflectance of a stereo object in an image. Unlike the previous approaches, these two components are not separated and processed individually in the proposed model. An unsupervised learning adaptation algorithm is developed to estimate the reflectance model <span class="hlt">based</span> on image intensities. In this algorithm, the PNL ICA method is used to obtain the <span class="hlt">surface</span> normal on each point of an image. Then, the 3-D <span class="hlt">surface</span> model is reconstructed <span class="hlt">based</span> on the estimated <span class="hlt">surface</span> normal on each point of image by using the enforcing integrability method. Two experiments are performed to assess the performance of the proposed approach. We test our algorithm on synthetically generated images for the reconstruction of <span class="hlt">surface</span> of objects and on a number of real images captured from the Yale Face Database B. These testing images contain variability due to illumination and varying albedo in each point of <span class="hlt">surface</span> of human faces. All the experimental results are compared to those of the existing photometric stereo approaches tested on the same images. The results clearly indicate the superiority of the proposed nonlinear reflectance model over the conventional Lambertian model and the other linear hybrid reflectance model. PMID:16342503</p> <div class="credits"> <p class="dwt_author">Lin, Chin-Teng; Cheng, Wen-Chang; Liang, Sheng-Fu</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">437</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JCoPh.228.7706L"> <span id="translatedtitle">A grid <span class="hlt">based</span> particle method for evolution of open curves and <span class="hlt">surfaces</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We propose a new numerical method for modeling motion of open curves in two dimensions and open <span class="hlt">surfaces</span> in three dimensions. Following the grid <span class="hlt">based</span> particle method we proposed in [S. Leung, H.K. Zhao, A grid <span class="hlt">based</span> particle method for moving interface problems. J. Comput. Phys. 228 (2009) 2993-3024], we represent the open curve or the open <span class="hlt">surface</span> by meshless Lagrangian particles sampled according to an underlying fixed Eulerian mesh. The underlying grid is used to provide a quasi-uniform sampling and neighboring information for meshless particles. The key idea in the current paper is to represent and to track end-points of the open curve and boundary-points of the open <span class="hlt">surface</span> explicitly and consistently with interior particles. We apply our algorithms to several applications including spiral crystal growth modeling and image segmentation using active contours.</p> <div class="credits"> <p class="dwt_author">Leung, Shingyu; Zhao, Hongkai</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">438</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JMiMi..15..270J"> <span id="translatedtitle">Paraffin <span class="hlt">surfaces</span> for culture-<span class="hlt">based</span> detection of mycobacteria in environmental samples</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper, we describe the development of paraffin <span class="hlt">surfaces</span> for culture-<span class="hlt">based</span> detection of mycobacteria in environmental samples. The <span class="hlt">surfaces</span> use the well-described paraffinophilic nature of mycobacteria to rapidly and selectively differentiate them from non-target microorganisms. New methods of depositing and patterning paraffin were developed, including using butanol or a heat gun to generate molten paraffin that was subsequently deposited by spin coating and patterned by wet and dry etching techniques. Using these techniques, 18 mm glass wafers with paraffin films of 10 70 µm were fabricated and subsequently etched to form different patterns. Prototype paraffin <span class="hlt">surfaces</span> were experimentally tested to demonstrate the concept of rapid and selective detection of mycobacteria in environmental samples collected from a municipal sewage treatment plant. Our successful demonstration of the culture-<span class="hlt">based</span> detection on paraffin substrates presents an alternative approach for tracking microorganisms in complex environmental samples.</p> <div class="credits"> <p class="dwt_author">Jing, Gaoshan; Eluru, Hima B.; Polaczyk, Amy; Kinkle, Brian; Oerther, Daniel B.; Papautsky, Ian</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">439</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23736415"> <span id="translatedtitle">Fundaments of optical far-field subwavelength resolution <span class="hlt">based</span> on illumination with <span class="hlt">surface</span> waves.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present a general discussion about the fundamental physical principles involved in a novel class of optical superlenses that permit to realize in the far-field direct non-scanning images with subwavelength resolution. Described superlenses are <span class="hlt">based</span> in the illumination of the object under observation with <span class="hlt">surface</span> waves excited by fluorescence, the enhanced transmission of fluorescence via coupling with <span class="hlt">surface</span> waves, and the occurrence of far-field coherence-related fluorescence diffraction phenomena. A Fourier optics description of the image formation <span class="hlt">based</span> on illumination with <span class="hlt">surface</span> waves is presented, and several recent experimental realizations of this technique are discussed. Our theoretical approach explains why images with subwavelength resolution can be formed directly in the microscope camera, without involving scanning or numerical post-processing. While resolution of the order of ?/7 has been demonstrated using the described approach, we anticipate that deeper optical subwavelength resolution should be expected. PMID:23736415</p> <div class="credits"> <p class="dwt_author">Lopez-Boada, Roberto; Regan, Charles J; Dominguez, Daniel; Bernussi, Ayrton A; Grave de Peralta, Luis</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">440</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23614498"> <span id="translatedtitle">Tunable <span class="hlt">surface</span> electron spin splitting with electric double-layer transistors <span class="hlt">based</span> on InN.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Electrically manipulating electron spins <span class="hlt">based</span> on Rashba spin-orbit coupling (SOC) is a key pathway for applications of spintronics and spin-<span class="hlt">based</span> quantum computation. Two-dimensional electron systems (2DESs) offer a particularly important SOC platform, where spin polarization can be tuned with an electric field perpendicular to the 2DES. Here, by measuring the tunable circular photogalvanic effect (CPGE), we present a room-temperature electric-field-modulated spin splitting of <span class="hlt">surface</span> electrons on InN epitaxial thin films that is a good candidate to realize spin injection. The <span class="hlt">surface</span> band bending and resulting CPGE current are successfully modulated by ionic liquid gating within an electric double-layer transistor configuration. The clear gate voltage dependence of CPGE current indicates that the spin splitting of the <span class="hlt">surface</span> electron accumulation layer is effectively tuned, providing a way to modulate the injected spin polarization in potential spintronic devices. PMID:23614498</p> <div class="credits"> <p class="dwt_author">Yin, Chunming; Yuan, Hongtao; Wang, Xinqiang; Liu, Shitao; Zhang, Shan; Tang, Ning; Xu, Fujun; Chen, Zhuoyu; Shimotani, Hidekazu; Iwasa, Yoshihiro; Chen, Yonghai; Ge, Weikun; Shen, Bo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-29</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_21");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a style="font-weight: bold;">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_23");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> </div><!-- page_22 div --> <div id="page_23" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_22");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a>