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Sample records for simulated curved canals

  1. Comparison of canal transportation in simulated curved canals prepared with ProTaper Universal and ProTaper Gold systems

    PubMed Central

    Muniz, Brenda Leite; Pires, Frederico; Belladonna, Felipe Gonçalves; Neves, Aline Almeida; Souza, Erick Miranda; De-Deus, Gustavo

    2016-01-01

    Objectives The purpose of this study was to assess the ability of ProTaper Gold (PTG, Dentsply Maillefer) in maintaining the original profile of root canal anatomy. For that, ProTaper Universal (PTU, Dentsply Maillefer) was used as reference techniques for comparison. Materials and Methods Twenty simulated curved canals manufactured in clear resin blocks were randomly assigned to 2 groups (n = 10) according to the system used for canal instrumentation: PTU and PTG groups, upto F2 files (25/0.08). Color stereomicroscopic images from each block were taken exactly at the same position before and after instrumentation. All image processing and data analysis were performed with an open source program (FIJI). Evaluation of canal transportation was obtained for two independent canal regions: straight and curved levels. Student's t test was used with a cut-off for significance set at α = 5%. Results Instrumentation systems significantly influenced canal transportation (p < 0.0001). A significant interaction between instrumentation system and root canal level (p < 0.0001) was found. PTU and PTG systems produced similar canal transportation at the straight part, while PTG system resulted in lower canal transportation than PTU system at the curved part. Canal transportation was higher at the curved canal portion (p < 0.0001). Conclusions PTG system produced overall less canal transportation in the curved portion when compared to PTU system. PMID:26877984

  2. Preparation of severely curved simulated root canals using engine-driven rotary and conventional hand instruments.

    PubMed

    Szep, S; Gerhardt, T; Leitzbach, C; Lüder, W; Heidemann, D

    2001-03-01

    This in vitro study evaluated the efficacy and safety of six different nickel-titanium engine-driven instruments used with a torque-controlled engine device and nickel-titanium hand and stainless steel hand instruments in preparation of curved canals. A total of 80 curved (36 degrees) simulated root canals were prepared. Images before and after were superimposed, and instrumentation areas were observed. Time of instrumentation, instrument failure, change in working length and weight loss were also recorded. Results show that stainless steel hand instruments cause significantly less transportation towards the inner wall of the canal than do nickel-titanium hand instruments. No instrument fracture occurred with hand instruments, but 30-60% breakage of instruments was recorded during instrumentation with the engine-driven devices. The working length was maintained by all types of instruments. Newly developed nickel-titanium rotary files were not able to prevent straightening of the severely curved canals when a torque-controlled engine-driven device was used.

  3. In vitro comparison of passive and continuous ultrasonic irrigation in curved root canals

    PubMed Central

    Castelo-Baz, Pablo; Varela-Patiño, Purificación; Cantatore, Giuseppe; Domínguez-Perez, Ana; Ruíz-Piñón, Manuel; Martín-Biedma, Benjamín

    2016-01-01

    Background The efficacy of endodontic irrigation procedures can be compromised by the complexity of the root canal system. Delivering irrigants to the apical third of curved canals presents a particular challenge to endodontists. This study compared the effects of two ultrasonic irrigation techniques on the penetration of sodium hypochlorite into the main canal and simulated lateral canals of curved roots in extracted teeth. Material and Methods Two sets of simulated lateral canals were created at 2, 4, and 6 mm from the working length in 60 single-rooted teeth (6 canals/tooth, n = 360 canals). The teeth were randomly divided into three experimental irrigation groups: group 1 (n = 20), positive pressure irrigation (PPI); group 2 (n = 20), passive ultrasonic irrigation (PUI); and group 3 (n = 20), continuous ultrasonic irrigation (CUI). To assess the irrigation solution penetration, 20% Chinese ink (Sanford Rotring GmbH, Hamburg, Germany) was added to a 5% sodium hypochlorite solution and delivered into the curved root canals. The penetration of contrast solution into the simulated lateral canals was scored by counting the number of lateral canals (0-2) penetrated to at least 50% of the total length. Results The CUI group showed significantly higher (P < 0.05) irrigant penetration into the lateral canals and into the apical third of the main canals. The PPI group showed significantly lower sodium hypochlorite penetration (P < 0.001) into the main and lateral canals compared with that in the CUI and PUI groups. Significantly higher irrigant penetration was observed in the PUI group than the PPI group. Conclusions Using CUI as the final rinse significantly increased the penetration of irrigant solution into the simulated lateral canals and apical third of curved roots. Key words:Continuous ultrasonic irrigation, curved root canals, passive ultrasonic irrigation, positive pressure irrigation, root canal irrigation. PMID:27703613

  4. Method for Constructing Standardized Simulated Root Canals.

    ERIC Educational Resources Information Center

    Schulz-Bongert, Udo; Weine, Franklin S.

    1990-01-01

    The construction of visual and manipulative aids, clear resin blocks with root-canal-like spaces, for simulation of root canals is explained. Time, materials, and techniques are discussed. The method allows for comparison of canals, creation of any configuration of canals, and easy presentation during instruction. (MSE)

  5. Simulating Supernova Light Curves

    SciTech Connect

    Even, Wesley Paul; Dolence, Joshua C.

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  6. Quantitative transportation assessment in curved canals prepared with an off-centered rectangular design system.

    PubMed

    Silva, Emmanuel João Nogueira Leal; Vieira, Vania Cristina Gomes; Tameirão, Michele Dias Nunes; Belladonna, Felipe Gonçalves; Neves, Aline de Almeida; Souza, Erick Miranda; DE-Deus, Gustavo

    2016-01-01

    The purpose of this study was to assess the ability of an off-centered rectangular design system [ProTaper Next (PTN)] to maintain the original profile of the root canal anatomy. To this end, ProTaper Universal (PTU), Reciproc (R) and WaveOne (WO) systems were used as reference techniques for comparison. Forty clear resin blocks with simulated curved root canals were randomly assigned to 4 groups (n = 10) according to the instrumentation system used: PTN, PTU, R and WO. Color stereomicroscopic images of each block were taken before and after instrumentation. All image processing and data analysis were performed with an open source program (Fiji v.1.47n). Evaluation of canal transportation was obtained for two independent regions: straight and curved portions. Univariate analysis of variance and Tukey's Honestly Significant Difference test were performed, and a cut-off for significance was set at α = 5%. Instrumentation systems significantly influenced canal transportation (p = 0.000). Overall, R induced significantly lower canal transportation compared with WO, PTN and PTU (p = 0.000). The curved portion displayed superior canal transportation compared to the straight one (p = 0.000). The significance of the difference among instrumentation systems varied according to the canal level evaluated (p = 0.000). In its straight portion, R and WO exhibited significantly lower transportation than PTN; whereas in the curved portion, R produced the lowest deviation. PTU exhibited the highest canal transportation at both levels. It can be concluded that PTN produced less canal transportation than PTU and WO; however, R exhibited better centering ability than PTN.

  7. [Engine-driven preparation of curved root canals: a platform to assess physical parameters].

    PubMed

    Peters, O A; Kappeler, S; Bucher, W; Barbakow, F

    2001-01-01

    The number of engine-driven rotary instruments available on the market is steadily increasing. These instruments enable clinicians to prepare better shaped root canals, however, rotary instruments have a higher risk for fracture than hand instruments. Unfortunately, the stresses placed on engine-driven rotary instruments in curved canals are insufficiently studied. The aim of this study was to develop a device which could measure more accurately the physical parameters influencing rotary instruments in curved canals. For this purpose, a specially designed machine was constructed to measure the torque which develops between the rotary instrument and the motor. Apical forces and penetration depths could also be directly measured in real time. A variety of other measurements was also possible because of other special set-ups integrated into the device. In the current study torque was assessed for GT-Files, size 35 with a .12 and sizes 20 with a .12 to .06 taper. In additions to preparations in simulated canals in plastic blocks, the "ISO 3630-1 specification for fracture moment" and "number of cycles till fatigue fracture" was measured. The findings indicated that when instruments were used for preparations, torques up to 40 Nmm were present. This exceeded the static fracture load, which was less than than 13 Nmm for the size 20 with .12 taper. In contrast, the number of rotations were more than 10 times lower when shaping canals in plastic blocks with a 5 mm radius of curvature than the number of rotations to fracture in the "cyclic fatigue test". This suggests that a GT-instrument could be used in ten canals. The apical force was always greater than 1 N and occasionally, 8 N or more was recorded. Further studies on natural teeth with varying canal geometries are required using the specially developed torsional machine to reduce the incidence of instrument fracture. In this way an efficient clinical potential can be confirmed for engine-driven rotary instruments in

  8. Engine-driven preparation of curved root canals: measuring cyclic fatigue and other physical parameters.

    PubMed

    Peters, Ove A; Kappeler, Stefan; Bucher, Willi; Barbakow, Fred

    2002-04-01

    An increasing number of engine-driven rotary systems are marketed to shape root canals. Although these systems may improve the quality of canal preparations, the risk for instrument fracture is also increased. Unfortunately, the stresses generated in rotary instruments when shaping curved root canals have not been adequately studied. Consequently, the aim of an ongoing project was to develop a measurement platform that could more accurately detail physical parameters generated in a simulated clinical situation. Such a platform was constructed by fitting a torque-measuring device between the rotating endodontic instrument and the motor driving it. Apically directed force and instrument insertion depth were also recorded. Additional devices were constructed to assess cyclic fatigue and static fracture loads. The current pilot study evaluated GT rotary instruments during the shaping of curved canals in plastic blocks as well as "ISO 3630-1 torque to fracture" and number of rotations required for fatigue fracture. Results indicated that torques in excess of 40 Nmm were generated by rotary GT-Files, a significantly higher figure than static fracture loads (less than 13 Nmm for the size 20. 12 GT-File). Furthermore, the number of rotations needed to shape simulated canals with a 5 mm radius of curvature in plastic blocks was 10 times lower than the number of rotations needed to fracture instruments in a "cyclic fatigue test". Apical forces were always greater than 1 N, and in some specimens, scores of 8 N or more were recorded. Further studies are required using extracted natural teeth, with their wide anatomical variation, in order to reduce the incidence of fracture of rotary instruments. In this way, the clinical potential of engine-driven rotary instruments to safely prepare curved canals can be fully appreciated.

  9. Cyclic Fatigue Resistance and Force Generated by OneShape Instruments during Curved Canal Preparation

    PubMed Central

    Zhang, Xiaolei

    2016-01-01

    Objectives To evaluate the cyclic fatigue resistance and the force generated by OneShape files during preparation of simulated curved canals. Methods Six OneShape files (the test) and six ProTaper F2 files (the control) were subject to the bending ability test. Another thirty files of each type were used to prepare artificial canals (n = 60), which were divided into 3 groups according to respective curvatures of the canals (30°, 60°, and 90°). The numbers of cycles to fatigue (NCF) as well as the positive and negative forces that were generated by files during canal preparation were recorded. The scanning electron microscopy was applied to detect the fracture surfaces. Results Compared with ProTaper F2 files, the bending loads of OneShape files were significantly lower at deflections of 45°(P < .05), 60° (P < .05) and 75° (P < .01). No significant difference was found at 30°. OneShape files presented a higher NCF in both 60° and 90° canals than the control (P < .01). No significant difference of NCF was found between OneShape and ProTaper files in 30° canals. During the preparation of 30° canals by both files, the negative forces were dominant. With the increase of the curvature, more positive forces were observed. When the OneShape Files were compared with the control, significant different forces were found at D3 and D2 (P < .05) in 30° canals, at D2 (P < .05), D1 (P < .01) and D0 (P < .01) in 60° canals, and at D4 and D3 (P < .01) in 90° canals. Conclusions OneShape files possessed a reliable flexibility and cyclic fatigue resistance. According to the assessments of the forces generated by files, OneShape instruments performed in a more fatigue-resistant way during curved canal preparation, compared with the ProTaper F2 files. PMID:27513666

  10. Maxillary lateral incisors with two canals and two separate curved roots

    PubMed Central

    Mohan, Ajit George; Rajesh, Ebenezar A. V.; George, Liza; Sujathan; Josy, Susan Ann

    2012-01-01

    Variation in the roots and root canal anatomy seems to be the norm rather than an exception. For a successful endodontic treatment, a clinician should have a thorough knowledge of the internal and external dental anatomy and its variations. Maxillary lateral incisors usually exhibit single canal with a single root. In this case, clinical examination and radiographs clearly demonstrates the presence of two root canals with two separate curved roots. This case report emphasizes the need for attention during endodontic management of maxillary lateral incisors. PMID:23633825

  11. Simulations of Closed Timelike Curves

    NASA Astrophysics Data System (ADS)

    Brun, Todd A.; Wilde, Mark M.

    2017-03-01

    Proposed models of closed timelike curves (CTCs) have been shown to enable powerful information-processing protocols. We examine the simulation of models of CTCs both by other models of CTCs and by physical systems without access to CTCs. We prove that the recently proposed transition probability CTCs (T-CTCs) are physically equivalent to postselection CTCs (P-CTCs), in the sense that one model can simulate the other with reasonable overhead. As a consequence, their information-processing capabilities are equivalent. We also describe a method for quantum computers to simulate Deutschian CTCs (but with a reasonable overhead only in some cases). In cases for which the overhead is reasonable, it might be possible to perform the simulation in a table-top experiment. This approach has the benefit of resolving some ambiguities associated with the equivalent circuit model of Ralph et al. Furthermore, we provide an explicit form for the state of the CTC system such that it is a maximum-entropy state, as prescribed by Deutsch.

  12. Spinal canal narrowing during simulated frontal impact.

    PubMed

    Ivancic, Paul C; Panjabi, Manohar M; Tominaga, Yasuhiro; Pearson, Adam M; Elena Gimenez, S; Maak, Travis G

    2006-06-01

    Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.

  13. Comparison of curved root canals preparation using reciprocating, continuous and an association of motions.

    PubMed

    Hoppe, Carolina Bender; Böttcher, Daiana Elisabeth; Justo, Aline Martins; Só, Marcus Vinícius Reis; Grecca, Fabiana Soares

    2016-09-01

    The aim of this study was to compare the rotary ProTaper Universal system, the single-file reciprocating WaveOne system and an association of motions assessing shaping ability, cleanliness, preparation time and instrument failures after preparation of curved root canals. Sixty root canals of extracted human molar teeth, with curvatures ranging between 20° and 40°, were divided into three groups, according with preparation system. Canals were prepared until apical size 25 using the ProTaper Universal system (G1), WaveOne (G2), or a hybrid technique (G3) associating reciprocating preparation with rotary glide path and cervical pre-enlargement. Teeth were scanned pre and post-operatively using computed tomography. Direction of transportation and centering ability of canals were measured using a computer image analysis program, and the results were analyzed statistically using one-way ANOVA. Preparation time was analyzed by one-way ANOVA and the Tukey post hoc test. Instrument failures were recorded. The amounts of debris and smear layer were quantified based on a numerical evaluation scale by scanning electron microscopy and were analyzed statistically using the Kruskal-Wallis test. No difference in transportation and centering ratio was found between the systems. Instrumentation with WaveOne was significantly faster than with other instruments (p < 0.05). During preparation, no instruments fractured and three suffered deformations. For debris removal and remaining smear layer, the results for the three groups were similar. The single-file reciprocating instrument was capable of providing faster root canal preparation with similar transporting, centralization and cleaning ability when compared with continuous and an association of motions in curved canals. SCANNING 38:462-468, 2016. © 2016 Wiley Periodicals, Inc.

  14. Centering and transportation: in vitro evaluation of continuous and reciprocating systems in curved root canals

    PubMed Central

    Navós, Beatriz Vilas; Hoppe, Carolina Bender; Mestieri, Leticia Boldrin; Böttcher, Daiana Elizabeth; Só, Marcus Vinicius Reis; Grecca, Fabiana Soares

    2016-01-01

    Context: One of the goals of endodontic therapy is the shaping and cleaning of the root canal system. In recent years, there has been multiple systems instrumentation, and changes in their dynamics are central to maintain the original shape of the canal after preparation. Aims: The aim of this study was to evaluate centering and transportation in curved root canals after using ProTaper® and MTwo® in continuous rotation, Reciproc® in reciprocating motion, and a step-down manual instrumentation technique. Settings and Design: Mesiobuccal roots of human extracted the first and second maxillary molars were selected and the canals (n = 60) were divided into four groups according to the preparation techniques: PT-ProTaper®; MT-MTwo®; RE-Reciproc®; MI-manual instrumentation. Subjects and Methods: The final apical diameter was standardized to a size 25. Centering and transportation were evaluated by cone-beam computed tomography and Adobe Photoshop 8.0 software. Statistical Analysis Used: The data were statistically analyzed by ANOVA and Tukey post hoc. Results: Results of transportation showed no statistical differences (P > 0.05) between groups, and significantly, difference (P < 0.05) between ProTaper® and Reciproc® was found when evaluating centering ability in the apical third. Conclusions: We concluded that there were no differences in transportation between the evaluated systems for the preparation of curved root canals with an apical instrumentation diameter of #25. For centering ability, in the apical third, ProTaper® presented worst behavior when compared to Reciproc®. PMID:27656071

  15. Evaluation of a solvent-softened gutta-percha obturation technique in curved canals.

    PubMed

    Moyer, P W; Osetek, E M; Ashkenaz, P; Gilbert, J L

    1995-09-01

    The purpose of this study was to compare the efficacy of three obturation techniques in curved canals. Twenty-four sets of three (triplets) morphologically similar molars having root curvatures of 45 to 90+ degrees were assembled. Following canal preparation, one sample from each group was obturated by either a halothane-dipped, a chloroform-dipped, or an untreated lateral condensation technique. Twenty triplets were cleared, evaluated, and graded for homogeneity of fill, canal wall adaptation, and replication of internal anatomy. Four triplets had windows prepared to expose the apical 6 mm of filling and were viewed with scanning electron microscopy. Kruskal-Wallis test of cleared teeth indicated a significant difference in favor of the solvent-softened techniques (p = 0.01). There was no difference between chloroform- and halothane-dipped groups (p = 0.03). Scanning electron microscope evaluations of halothane-dipped samples revealed more homogeneous fills with greater canal replication than untreated gutta-percha. In addition, halothane-treated samples had appreciably less surface porosity than chloroform. Lateral condensation of halothane-treated gutta-percha was judged to be a viable obturation technique.

  16. Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography.

    PubMed

    Freire, Laila Gonzales; Gavini, Giulio; Cunha, Rodrigo Sanches; Santos, Marcelo dos

    2012-01-01

    The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

  17. Canals

    ERIC Educational Resources Information Center

    Winkleman, Michael

    1974-01-01

    In the mid-1800's, the canal system in the U.S. was thriving. But, by the end of that century, roads and railways had replaced these commercial thoroughfares. Renewed interest in the abandoned canals is now resulting in renovation and ecological site development in Pennsylvania and New Jersey. (MA)

  18. Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals

    PubMed Central

    Sabino, C. P.; Garcez, A. S.; Núñez, S. C.; Ribeiro, M. S.; Hamblin, M. R.

    2014-01-01

    Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 µM) was introduced into the canals and then irradiated (λ=660 nm, P=100 mW, beam diameter=2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency. PMID:25060900

  19. Comparative evaluation of shaping ability of different rotary NiTi instruments in curved canals using CBCT

    PubMed Central

    Arora, Anshul; Taneja, Sonali; Kumar, Mohit

    2014-01-01

    Aim: The aim of this study was to compare the canal transportation, canal centering ability, and time taken for preparation of curved root canals after instrumentation with ProFile GT Series X (GTX) files, Revo-S files, twisted files, and Mtwo files by using cone-beam computed tomography (CBCT). Materials and Methods: Forty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20 to 40 were divided according to the instrument used in canal preparation into four groups of 10 samples each: GTX (group I), Revo-S (group II), twisted file (group III), and Mtwo (group IV). The teeth were instrumented according to manufacturer's guidelines, with all groups being prepared to size 30, 0.06 taper master apical file. Canals were scanned using an i-CAT CBCT scanner (Imaging Science International, Hatfield, PA, USA) before and after preparation to evaluate the transportation and centering ratio at 3 mm, 5 mm, 7 mm, 9 mm, and 11 mm from the apex. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference (HSD) test. Results: Twisted file system showed significantly least canal transportation and highest canal centering ability values as compared to GTX, Revo-S, and Mtwo file systems. Overall, GTX, Revo-S, and Mtwo showed comparable results with respect to canal transportation and centering ability. Conclusion: The innovative method of manufacturing the TF system resulted in superior shaping ability in curved canals, with the instruments remaining more centered and producing less canal transportation than GTX, Revo-S, and Mtwo file systems. PMID:24554858

  20. Working length changes in curved canals after coronal flaring by using rotary files and hand file: An in vitro study

    PubMed Central

    Kumar, Rahul; Khambete, Neha; Patil, Suvarna; Hoshing, Upendra; Medha, Ashish; Shetty, Roshan

    2013-01-01

    Aim: This in vitro investigation examined the effect of early coronal flaring (CF) and late CF on the working length (WL) in curved root canals. Background: The objective of this study was to determine if canal length is altered as a result of CF in curved canals of molar roots. Study Design: The conditions compared were combinations of (a) stainless steel hand files using Gates Glidden (G. G.) drills (SS) versus nickel-titanium rotary files (Ni-Ti); and (b) early CF (flaring completed before WL determination) versus late CF (flaring completed after WL determination). Selected were 90 canals of extracted maxillary or mandibular first molars (mesial root of mandibular molars and the mesiobuccal root of the maxillary molars) from three groups. CF was accomplished for the SS group using G. G. drills and for the Ni-Ti group using rotary ProTaper and Hero Shaper files. WL was determined by a digital vernier caliper before CF, immediately after CF, and again after canal preparation. Statistical Analysis: A repeated measures analysis of variance (ANOVA) test and a Tukey's multiple prosthoc test were used for this study. Results: Results indicated that WL decreased for all canals as a result of canal preparation. The mean decrease in WL was significantly greater for the SS group (−0.77 ± 0.42 mm) than for the Ni-Ti groups (−0.33 mm ± 0.44). Less change in WL occurred in all groups when initial WL was determined after CF. Conclusion: WL in curved canals consistently decreases during the course of instrumentation. Clinician should keep this in mind for better treatment outcome. PMID:24082566

  1. Linear measurements to determine working length of curved canals with fine files: conventional versus digital radiography.

    PubMed

    Brito-Júnior, Manoel; Santos, Luis A N; Baleeiro, Erika N; Pêgo, Marisa M F; Eleutério, Núbia B; Camilo, Carla C

    2009-12-01

    This in vitro study compared conventional and digital radiographic linear measurements to determine the working length (WL) of curved canals with fine endodontic files. In total, 30 mesiobuccal root canals in molars were measured with a #06 K-file to a length 1 mm short of the apical foramen (WL1). Teeth were mounted in plastic blocks and standardized periapical radiographs were obtained by conventional and digital (Digora Optime) radiographic methods with #06, #08 and #10 K-files positioned in WL1. Two independent and calibrated examiners performed the conventional measurements with a millimeter ruler, from the file stop to the file tip (WL2). For the digital images, examiners used the linear measurement tool on the Digora software, in original mode (WL3). For comparison of WL1, WL2 and WL3, the Wilcoxon test (P < 0.05) was applied and the reproducibility of the measurements was assessed. There was no statistically significant difference between Wl2 and Wl3 for #06, #08 and #10 K-files (P = 0.341, 0.641 and 0.232, respectively), with an acceptable level of interexaminer agreement. The measurements of Wl2 and Wl3 were significantly (P < 0.05) larger than those of WL1. No difference was observed among the linear measures obtained with either radiographic method, which showed higher WL values than the direct measurements.

  2. Effect of Patency File on Transportation and Curve Straightening in Canal Preparation with ProTaper System.

    PubMed

    Hasheminia, Seyed Mohsen; Farhadi, Nastaran; Shokraneh, Ali

    2013-01-01

    The aim of this ex vivo study was to evaluate the effect of using a patency file on apical transportation and curve straightening during canal instrumentation with the ProTaper rotary system. Seventy permanent mandibular first molars with mesiobuccal canals, measuring 18-23 mm in length and with a 25-40° curvature (according to the Schneider method), were selected. The working lengths were determined and the teeth were mounted and divided into two experimental groups: (A) prepared by the ProTaper system without using a patency file (n = 35) and (B) prepared by the ProTaper system using a patency file (n = 35). Radiographs taken before and after the preparation were imported into Photoshop software and the apical transportation, and curve straightening were measured. Data were analyzed using independent t-test. Partial correlation analysis was performed to evaluate the relationship between the initial curvature, transportation, and curve straightening (α = 0.05). Using a patency file during canal preparation significantly decreased both apical transportation and curve straightening (P < 0.001). There were significant relationships between the angle of curvature, transportation and curve straightening in pairs (P < 0.001). Apical patency is recommended during root canal preparation with the ProTaper rotary system.

  3. Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals.

    PubMed

    Sabino, C P; Garcez, A S; Núñez, S C; Ribeiro, M S; Hamblin, M R

    2015-08-01

    Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in  vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 μM) was introduced into the canals and then irradiated (λ = 660 nm, P = 100 mW, beam diameter = 2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency.

  4. Experimental simulation of closed timelike curves

    NASA Astrophysics Data System (ADS)

    Ringbauer, Martin; Broome, Matthew A.; Myers, Casey R.; White, Andrew G.; Ralph, Timothy C.

    2014-06-01

    Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein’s field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics—essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence.

  5. Experimental simulation of closed timelike curves.

    PubMed

    Ringbauer, Martin; Broome, Matthew A; Myers, Casey R; White, Andrew G; Ralph, Timothy C

    2014-06-19

    Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics--essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence.

  6. Efficacy of different solvents in removing gutta-percha from curved root canals: a micro-computed tomography study.

    PubMed

    Sağlam, Baran Can; Koçak, Mustafa Murat; Türker, Sevinç Aktemur; Koçak, Sibel

    2014-08-01

    The aim of this study was to compare the root filling material that remained after retreatment of curved root canals with chloroform and Endosolv R as solvents. The evaluation employed micro-computed tomography (CT) imaging. Thirty-six extracted molar teeth with curved roots were selected. After preparation with ProTaper rotary instruments, the canals were filled with gutta-percha and AH26 sealer. The teeth were randomly divided into three groups according to solvent used (n = 12) as follows: group 1: chloroform; group 2: Endosolv R; group 3: no solvent (negative control). ProTaper Universal Retreatment files were used to remove each root canal filling and then the self-adjusting file was applied for two minutes. Preoperative and postoperative micro-CT images were used to assess the percentage of residual filling material. The mean percentage of residual filling material was quantified. There were no statistically significant differences between the groups in terms of percentage volume of residual root canal filling.

  7. Matters of simulation of the semicircular canal system

    NASA Technical Reports Server (NTRS)

    Gurfinkel, V. S.; Petukhov, S. V.

    1977-01-01

    A scale model of the human semicircular canal system was developed based on the theory of dynamic similitude. This enlarged model makes it convenient to conduct tests on the vestibular processes and dynamics in the semicircular canals. Tests revealed hydromechanical interaction between canals, with asymmetry of the conditions of movement of the endolymph in the canals in opposite directions. A type of vestibular reactions, occurring with angular oscillations of the head, was predicted and demonstrated using this model and human test subjects.

  8. A comparative evaluation of gutta-percha filled areas in curved root canals obturated with different techniques.

    PubMed

    Schäfer, Edgar; Nelius, Birthe; Bürklein, Sebastian

    2012-02-01

    The aim of this study was to compare different obturation techniques in severely curved canals in terms of the percentage of gutta-percha filled area and voids. The obturation times and the incidence of extrusion of filling material were also compared. Curved root canals (curvature, 25-35°) of 48 extracted human teeth were enlarged with Mtwo rotary NiTi instruments and obturated as follows: Group A: 0.04/35 matched-single-cone; Group B: cold lateral compaction with 0.04/35 gutta-percha master cone; Group C: warm vertical compaction; Group D: lateral compaction with standardized gutta-percha master cone. In all groups AHPlus was used as sealer. The teeth were sectioned horizontally at 2, 3, 4, 6 and 8 mm from the apex. The total area of each canal segment was measured and the areas of gutta-percha, sealer and voids were converted to percentages of the total area. Data were subjected to the Kruskal-Wallis and post hoc Dunn test. Obturation times were compared using ANOVA and post hoc Student-Newman-Keuls test. The matched-single-cone obturation (group A) was significantly the fastest method while warm vertical compaction (group C) required significantly more time than all other techniques (p < 0.05). No significant differences were obtained between the groups in terms of percentage of voids at any level (p > 0.05). At all levels, groups B, C, and D produced significantly higher gutta-percha filled areas (p < 0.05) and lower sealer-filled areas (p < 0.05) than group A. No significant differences were found between groups B, C, and D (p > 0.05) regarding gutta-percha and sealer-filled areas. Within the limitations of the in vitro study, it can be concluded that lateral compaction of greater taper gutta-percha cones is a fast and efficient method for obturation of curved canals.

  9. IERAPSI project: simulation of a canal wall-up mastoidectomy.

    PubMed

    Neri, E; Sellari Franceschini, S; Berrettini, S; Caramella, D; Bartolozzi, C

    2006-03-01

    Among the various EU research projects concerning the medical application of virtual reality, the project Ist-1999-12175, called IERAPSI (Integrated Environment for the Rehearsal and Planning of Surgical Interventions), specifically addressed the creation of a virtual and interactive surgical field for the temporal bone using three-dimensional images derived from CT data. We report on the experience obtained in the IERAPSI project in simulating a canal wall-up mastoidectomy. A surgeon with extensive experience in surgery of the petrous bone performed the mastoidectomy. The operative field included the mastoid, with its substantial differences in density between the cortex and the pneumatized bone, together with soft tissue structures, both on the border and inside the bone. The simulation is better in the first part of the operation than in the second part, suffering from a lack of haptic feedback from soft tissue and the surgical tool in deeper contexts, and under-representation of the variability inherent in pneumatized bone. This said, the excellent representation of dust production and removal, 3D simulation through color, and very good visual and haptic feedback in the early stage of the procedure are impressive. IERAPSI represents a potential surgical planning theater for the training of students and young surgeons, but is also expected to aid expert surgeons in the preoperative planning of difficult cases.

  10. Efficacy of Reciproc® and Profile® Instruments in the Removal of Gutta-Percha from Straight and Curved Root Canals ex Vivo

    PubMed Central

    Marfisi, Karem; Plotino, Gianluca; Clavel, Tatiana; Duran-Sindreu, Fernando; Roig, Miguel

    2015-01-01

    ABSTRACT Objectives To compare the efficacy of Reciproc® (VDW GmbH) and ProFile® (Dentsply Maillefer) instruments at removing gutta-percha from straight and curved root canals ex vivo filled using the cold lateral condensation and GuttaMaster® (VDW GmbH) techniques. Material and Methods Forty mesial roots of mandibular molars with two curved canals and 80 single-rooted teeth with straight root canals, a total of 160 root canals, were randomly assigned to eight groups (canals per group = 20) according to filling technique, retreatment instrument and root canal curvature as follows: Group I, cold lateral condensation/ProFile®/straight; Group II, cold lateral condensation/ProFile®/curved; Group III, cold lateral condensation/Reciproc®/straight; Group IV, cold lateral condensation/Reciproc®/curved; Group V, GuttaMaster®/ProFile®/straight; Group VI, GuttaMaster®/ProFile®/curved; Group VII, GuttaMaster®/Reciproc®/straight; and Group VIII, GuttaMaster®/Reciproc®/curved. The following data were recorded: procedural errors, retreatment duration and canal wall cleanliness. Means and standard deviations were calculated and analysed using the Kruskal-Wallis test, one-way analysis of variance and Tukey’s test (P < 0.05). Results Reciproc® instruments were significantly faster than ProFile® instruments at removing GuttaMaster® from both straight (P = 0.0001) and curved (P = 0.0003) root canals. Reciproc® were statistically more effective than ProFile® instruments in removing GuttaMaster® from straight root canals (P = 0.021). Regardless of filling technique or retreatment instrument, gutta-percha was removed more rapidly from curved than from straight root canals (P = 0.0001). Conclusions Neither system completely removed filling material from the root canals. Compared with ProFile® instruments, Reciproc® instruments removed GuttaMaster® filling material from straight and curved root canals more rapidly. PMID:26539283

  11. Computer simulation and capacity evaluation of Panama Canal alternatives

    SciTech Connect

    Rosselli, A.T.; Bronzini, M.S.; Weekly, D.A.

    1994-12-31

    The Operating Characteristics and Capacity Evaluation (OCCE) Study was one of the components of a group of studies of future alternatives to the Panama Canal, sponsored by a study commission formed by the governments of Panama, the US and Japan. The basic tool in the conduct of the study was the Waterway Analysis Model (WAM), developed originally by the US Army Corps of Engineers for use on the US inland waterway system and adapted under OCCE for study of Panama Canal alternatives. The study synthesized the many alternative plans for the Canal proposed historically into four basic groups: High-Rise Lock Canal, Low-Rise Lock Canal, Sea-Level Canal and Status Quo Canal. For economy, the sea-level cases were based on, essentially, a single-lane canal, in conjunction with the status quo canal. Hydraulic and navigation studies indicted that to achieve safe navigation, tide gates or locks would be required to control currents that would otherwise be generated by the differences in tides between the two oceans. The alternatives studied in detail are illustrated in the body of the paper.

  12. In vitro Comparison of Apical Debris Extrusion Using Rotary and Reciprocating Systems in Severely Curved Root Canals

    PubMed Central

    Delvarani, Abbas; Mohammadzadeh Akhlaghi, Nahid; Aminirad, Raana; Tour Savadkouhi, Sohrab; Vahdati, Seyed Aliakbar

    2017-01-01

    Introduction: The aim of this in vitro study was to compare the amount of apically extruded debris after root canal preparation using rotary and reciprocating systems in severely curved root canals. Methods and Materials: Thirty six extracted human mandibular first molars with 25-35° curvature in their mesiobuccal (MB) canal (according to Schneider’s method) were cleaned and shaped with ProTaper and WaveOne systems. The extruded debris was collected and their net weight was calculated. To compare the efficiency of the two systems, the operation time was also measured. The data were analyzed with t-test. Results: The amount of extruded debris in WaveOne group was significantly greater in comparison with ProTaper group (26%). The operating time for ProTaper was however, significantly longer than WaveOne. Conclusion: Both root preparation systems caused some degree of debris extrusion through the apical foramen. However, this amount was greater in WaveOne instruments. PMID:28179921

  13. Suitable Conditions of Reservoir Simulation for Searching Rule Curves

    NASA Astrophysics Data System (ADS)

    Kangrang, Anongrit; Chaleeraktrakoon, Chavalit

    The objective of this study is to carry out a suitable length of inflow record using in the simulation model. The second objective is to find an effect of initial reservoir capacity of reservoir simulation for searching the optimal rule curves. The reservoir simulation model was connected with genetic algorithms to search the optimal rule curves quickly. The model has been applied to determine the optimal rule curves of the Bhumibol and Sirikit Reservoirs (the Chao Phraya River Basin, Thailand). The optimal rule curves of each condition were used to assess by a Monte Carlo simulation. The results show that the shortest period of dry inflow record using in the simulation model in order to search the optimal rule curves is 10 year. Furthermore, the minimum initial capacity of reservoir for searching optimal rule curves is 10% of full capacity.

  14. Effect of glide path and apical preparation size on the incidence of apical crack during the canal preparation using Reciproc, WaveOne, and ProTaper Next systems in curved root canals: A stereomicroscope study.

    PubMed

    Topçuoğlu, Hüseyin Sinan; Düzgün, Salih; Akpek, Firdevs; Topçuoğlu, Gamze

    2016-11-01

    This study evaluated the effect of creating a glide path and apical preparation size on the incidence of apical cracks during canal preparation in mandibular molar teeth with curved canals. One hundred and forty extracted teeth were used. The teeth were randomly assigned to one control group or six experimental groups (n = 20 per group) for canal preparation. No preparation was performed on teeth in the control group. In three of the six experimental groups, a glide path was not created; a glide path was created on the curved mesial canals of all teeth in the remaining three experimental groups. All teeth in experimental groups were then instrumented with the following systems: Reciproc, WaveOne (WO), and ProTaper Next (PTN). Digital images of the apical root surfaces of these teeth were recorded before preparation, after instrumentation with size 25 files, and after instrumentation with size 40 files. The images were then inspected for the presence of any new apical cracks and propagation. There was no significant difference between the experimental groups during canal preparation using size 25 files (p > 0.05). Reciproc and WO caused more new apical cracks than did PTN during canal preparation using size 40 files (p < 0.05). However, canal preparation using size 40 files did not cause propagation of existing cracks (p > 0.05). Performing a glide path prior to canal preparation did not change the incidence of apical crack during preparation. Additionally, increasing apical preparation size may increase the incidence of apical crack during canal preparation. SCANNING 38:585-590, 2016. © 2016 Wiley Periodicals, Inc.

  15. A novel image processing and measurement system applied to quantitative analysis of simulated tooth root canal shape

    NASA Astrophysics Data System (ADS)

    Yong, Tao; Yong, Wei; Jin, Guofan; Gao, Xuejun

    2005-02-01

    Dental pulp is located in root canal of tooth. To modern root canal therapy, "Root canal preparation" is the main means to debride dental pulp infection. The shape of root canal will be changed after preparation, so, when assessing the preparation instruments and techniques, the root canal shaping ability especially the apical offset is very important factor. In this paper, a novel digital image processing and measurement system is designed and applied to quantitative analysis of simulated canal shape. By image pretreatment, feature extraction, registration and fusion, the variation of the root canals' characteristics (before and after preparation) can be accurately compared and measured, so as to assess the shaping ability of instruments. When the scanning resolution is 1200dpi or higher, the registration and measurement precision of the system can achieve 0.021mm or higher. The performance of the system is tested by a series of simulated root canals and stainless steel K-files.

  16. Filling of simulated lateral canals with gutta percha or resilon when using thermomechanical compaction

    PubMed Central

    Anna-Júnior, Arnaldo Sant’; Tanomaru-Filho, Mário; Duarte, Marco Antônio Hungaro; da Silva, Guilherme Ferreira; Bosso, Roberta; Guerreiro-Tanomaru, Juliane M.

    2014-01-01

    Aims: To evaluate the filling of simulated lateral canals with gutta-percha or Resilon when using thermomechanical compaction. Setting and Design: Forty-five human single-rooted teeth were subjected to tooth decalcification and clearing. Materials and Methods: After root canal preparation, artificial lateral canals were made at 2, 5, and 8 mm from the working length (WL), corresponding to the apical, middle, and cervical thirds, respectively. The specimens were divided (n = 15) according to the filling material: Dentsply gutta-percha (GD), Odous gutta-percha (GO), and Resilon cones (RE). Root canals were obturated by thermomechanical compaction using a #45 compactor and no sealer. Lateral canals were analyzed by digital radiography and digital images after tooth decalcification and clearing using the Image Tool software. Statistical Analysis Used: Data were subjected to the Kruskal-Wallis and Dunn tests at 5% significance. Results: In the coronal third, RE and GO presented more filling ability than GD (P < 0.05). In the middle and apical thirds, RE presented the best results. Conclusions: Resilon demonstrated filling ability as material for root canal obturation by using thermomechanical compaction. PMID:24944441

  17. Computed Tomography Evaluation of Canal Transportation and Volumetric Changes in Root Canal Dentin of Curved Canals Using Mtwo, ProTaper and ProTaper Next Rotary System-An In-vitro Study

    PubMed Central

    Shivashankar, Mayuri Biccodu; Jayasheel, Arun; Kenchanagoudra, Mallikarjun Goud

    2016-01-01

    Introduction Complete cleaning and shaping of root canal system is of paramount importance to achieve a successful root canal treatment. There are various rotary Ni-Ti systems available in the market to achieve mechanical goal of root canal preparation. But aggressive preparation of root canal with such systems would result in canal transportation and excess root dentin removal that would be one of the major reasons to decide the prognosis of root canal treated tooth. Aim The present study was conducted to compare the root canal preparation in terms of canal transportation and volumetric changes in the root canal dentin among three Ni-Ti file systems, namely Mtwo, ProTaper (PT) and ProTaper NEXT (PTN) file system, using Computed Tomography (CT). Materials and Methods A total of 45 mesiobuccal root canals of extracted first molar teeth with completely formed root apices and angle of curvature ranging between 10°- 35° were selected. These teeth were randomly divided into three experimental groups containing 15 teeth each, based on rotary system used. Group-I: Mtwo files, Group-II: PT files and Group-III: PTN files. Pre-instrumentation CT images were obtained at three cross-sectional planes – 3mm, 7mm and 11mm from apical end of the root. Similarly, post-instrumentation images were obtained. Shortest distance from the edge of the canal to the periphery of the root was analyzed by using Analysis of Variance. Results All three file systems tested in the present study presented similar behaviour with respect to the root canal transportation. Lesser canal transportation was recorded in Mtwo. But no statistically significant difference was seen in terms of canal transportation and volume of dentin removed between all three rotary systems (p>0.05). Conclusion Mtwo, PT and PTN rotary systems have similar behaviour with respect to canal transportation and volume of dentin removed. PMID:28050495

  18. 3D Analysis of D-RaCe and Self-Adjusting File in Removing Filling Materials from Curved Root Canals Instrumented and Filled with Different Techniques

    PubMed Central

    Simsek, Neslihan; Ahmetoglu, Fuat; Bulut, Elcin Tekin; Er, Kursat

    2014-01-01

    The aim of this study was to compare the efficacy of D-RaCe files and a self-adjusting file (SAF) system in removing filling material from curved root canals instrumented and filled with different techniques by using microcomputed tomography (micro-CT). The mesial roots of 20 extracted mandibular first molars were used. Root canals (mesiobuccal and mesiolingual) were instrumented with SAF or Revo-S. The canals were then filled with gutta-percha and AH Plus sealer using cold lateral compaction or thermoplasticized injectable techniques. The root fillings were first removed with D-RaCe (Step 1), followed by Step 2, in which a SAF system was used to remove the residual fillings in all groups. Micro-CT scans were used to measure the volume of residual filling after root canal filling, reinstrumentation with D-RaCe (Step 1), and reinstrumentation with SAF (Step 2). Data were analyzed using Wilcoxon and Kruskal-Wallis tests. There were no statistically significant differences between filling techniques in the canals instrumented with SAF (P = 0.292) and Revo-S (P = 0.306). The amount of remaining filling material was similar in all groups (P = 0.363); all of the instrumentation techniques left filling residue inside the canals. However, the additional use of SAF was more effective than using D-RaCe alone. PMID:25114976

  19. Comparison of Hero 642 and K3 rotary nickel-titanium files in curved canals of molars and a systematic review of the literature

    PubMed Central

    CAI, HUA-XIONG; CHENG, HUI-LING; SONG, JIE-WEN; CHEN, SU-YA

    2014-01-01

    The aim of the present study was to compare the root canal preparation ability of rotary nickel-titanium (NiTi) Hero 642 and K3 files in curved mandibular or maxillary molars. A total of 40 extracted mandibular molars with two separate mesial canals, an apical width of approximately size ≤15 and a root canal curvature of 15–30° were randomly divided into two groups and instrumented using Hero 642 (n=20) or K3 files (n=20). Canal straightening, working length, transportation, cross-sectional area, minimum dentin thickness and the canal angle curvature degree were examined, and a systematic review of the literature was conducted. No statistically significant differences were observed between the two groups with regard to the mean degree of straightening, mean change in working length, mean transportation, amount of dentin removed or remaining minimum dentin thickness (P>0.05). The canal angle curvature decreased in the two groups postoperatively. The systematic review identified six studies, and overall the two files performed similarly in the majority of categories examined. Therefore, the rotary NiTi Hero 642 and K3 files demonstrated comparable shaping abilities and maintenance of working length. PMID:25187795

  20. Comparison of the shaping ability of RaCe, FlexMaster, and ProFile nickel-titanium instruments in severely curved root canals

    PubMed Central

    Burkhardt, Lea; Weidmann, Frank; Rüttermann, Stefan

    2016-01-01

    Background This in vitro study compared the shaping ability of RaCe, FlexMaster, and ProFile rotary nickel-titanium instruments in severely curved root canals of extracted teeth. Material and Methods Sixty maxillary molars with curvatures ranging from 25° to 65° were embedded in a muffle system and portioned into five horizontal sections (thickness 1.2 mm), starting from the apex. Canals were divided into three groups (n = 20, each) and were prepared with RaCe, FlexMaster, or ProFile rotary nickel-titanium instruments and the TriAuto ZX handpiece using a crown-down preparation technique. We evaluated the difference between pre- and postoperative root canal cross-sections, loss of working length, instrument failure, and preparation time. The root canal area before and after the intervention was determined using an area-measuring software. The data were analyzed statistically using a one-way ANOVA followed by a Kruskal-Wallis multiple-comparison Z-value test. Results Specimens treated with FlexMaster showed the greatest change from preoperative cross-sections, followed by RaCe and ProFile. The cross-sectional changes induced by RaCe and FlexMaster preparation differed significantly from those produced by ProFile. Loss of working length, instrument failure, and preparation time did not differ significantly between the groups. Conclusions Root canal preparation with the three instruments did not lead to any significant alteration of the original root anatomy or working length. Thus, we conclude that RaCe, FlexMaster, and ProFile instruments are of comparable efficiency and usefulness in the preparation of severely curved root canals. Key words:Endodontics, root canal preparation, rotary, extracted teeth, nickel-titanium. PMID:27957264

  1. A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study

    PubMed Central

    Prasanthi, Nalam NVD; Rambabu, Tanikonda; Sajjan, Girija S; Varma, K Madhu; Satish, R Kalyan; Padmaja, M

    2016-01-01

    Aim: The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions. Materials and Methods: Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans. Statistical Analysis: The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests. Results: Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups. Conclusion: LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems. PMID:27656062

  2. Simulation and video animation of canal flushing created by a tide gate

    USGS Publications Warehouse

    Schoellhamer, David H.

    1988-01-01

    A tide-gate algorithm was added to a one-dimensional unsteady flow model that was calibrated, verified, and used to determine the locations of as many as five tide gates that would maximize flushing in two canal systems. Results from the flow model were used to run a branched Lagrangian transport model to simulate the flushing of a conservative constituent from the canal systems both with and without tide gates. A tide gate produces a part-time riverine flow through the canal system that improves flushing along the flow path created by the tide gate. Flushing with no tide gates and with a single optimally located tide gate are shown with a video animation.

  3. Effectiveness of XP-endo Finisher, EndoActivator, and File agitation on debris and smear layer removal in curved root canals: a comparative study.

    PubMed

    Elnaghy, Amr M; Mandorah, Ayman; Elsaka, Shaymaa E

    2017-04-01

    The purpose of this study was to assess the efficacy of the XP-endo Finisher (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) file on debris and smear layer removal in curved root canals in comparison to different irrigation regimens. Seventy-five freshly extracted human mandibular molar teeth with mesial root curved more than 20° were used in this study. The mesial root canals were mechanically prepared using the BT-Race rotary system (FKG Dentaire) and divided into five groups (n = 15) according to the following irrigation techniques: positive control, non-agitated, File agitation, XP-endo Finisher, and EndoActivator (Dentsply Tulsa Dental Specialities, Tulsa, OK, USA). Root canals were split longitudinally and evaluated by scanning electron microscopy. Five-grade scoring system was used to assess the presence of debris and smear layer at the coronal, middle, and apical regions. The XP-endo Finisher and EndoActivator groups revealed significantly lower debris and smear layer scores than the other groups at the coronal, middle, and apical regions (P < 0.05). There was no significant difference between XP-endo Finisher and EndoActivator groups (P > 0.05). The apical region had higher debris and smear layer scores compared with the coronal regions in all groups (P < 0.05), except for the positive control group; there was no significant difference between the three regions of the root canal (P > 0.05). Irrigation of curved root canals using XP-endo Finisher and EndoActivator methods appears to be more effective on debris and smear layer removal than the other tested groups.

  4. Apical Extrusion of Debris after Canal Preparation with Hand-Files Used Manually or Installed on Reciprocating Air-Driven Handpiece in Straight and Curved Canals

    PubMed Central

    Labbaf, Hossein; Shakeri, Leila; Orduie, Reza; Bastami, Farshid

    2015-01-01

    Introduction: Apical debris extrusion (DE) subsequent to root canal instrumentation, is one of the most important causes of endodontic flare-ups. The aim of this study was to compare the amount of DE after root canal instrumentation using nickel-titanium (NiTi) hand files with step-back manual technique or installed on reciprocating handpiece. Methods and Materials: This study was conducted on mesiobuccal (MB) roots of extracted maxillary first molars (n=20) and roots of mandibular premolars (n=20) that were randomly divided into two groups (n=20) according to the armamentarium used for canal preparation (air-driven reciprocating handpiece or hand instrumentation). In each group, the MB and premolar roots were prepared with the main apical sizes of 35 and 40, respectively. The extruded debris were collected and weighed. Finally, the mean dry weights were compared using ANOVA and t-test, and Tukey’s Multiple Comparisons Procedures were used to determine the significant differences in amounts of DE. The level of significance was set at 0.05. Results: Regardless of the type of teeth, the mean values of DE, were significantly lower in the handpiece group (P<0.0001). In addition, significantly lower amounts of DE was observed in premolars in similar group (P<0.001). However, this difference was not significant in MB roots of molars (P=0.20). Conclusion: Root canal preparation with reciprocating handpiece can lead to significantly lower debris extrusion than the manual step-back technique. In handpiece-prepared canals, the amount of extruded debris was significantly lower in premolar teeth. PMID:26213538

  5. [Deformations occurring in the apical third of curved root canals during biomechanical preparation using manual impulsion-traction techniques].

    PubMed

    Roig Cayón, M; Basilio Monné, J; Canalda Sahli, C

    1990-01-01

    Apical deformations, specially zips and elbows, during instrumentation of the root canals, are studied. The authors study why do they appear, their effect on endodontic therapy, and the way of avoiding them.

  6. Effect of early coronal flaring on working length change in curved canals using rotary nickel-titanium versus stainless steel instruments.

    PubMed

    Davis, R Dean; Marshall, J Gordon; Baumgartner, J Craig

    2002-06-01

    This in vitro investigation examined pre- and postinstrumentation working length (WL) measurements in curved root canals. The conditions compared were combinations of (a) stainless steel hand files + Gates Glidden drills (SS) versus nickel-titanium rotary files (Ni-Ti); and (b) early coronal flaring (flaring completed before WL determination) versus late coronal flaring (flaring completed after WL determination). Coronal flaring was accomplished for the SS group using Gates Glidden drills and for the Ni-Ti group using rotary Ni-Ti files (n = 15/group). WL was determined before coronal flaring, immediately after coronal flaring, and again after canal preparation. Results indicated that WL decreased for all canals as a result of canal preparation. The mean decrease in WL was significantly greater for the SS group (-0.48 mm +/- 0.32) than for the Ni-Ti group (-0.22 mm +/- 0.26). Less change in WL occurred in both groups when initial WL was determined after coronal flaring (SS: -0.12 mm +/- 0.13, Ni-Ti: -0.14 mm +/- 0.25).

  7. Visualization of removal of trapped air from the apical region in simulated root canals by laser-activated irrigation using an Er,Cr:YSGG laser.

    PubMed

    Peeters, Harry Huiz; De Moor, Roeland J G; Suharto, Djoko

    2015-08-01

    The aim of this visualization study was to obtain a better understanding of the mechanism by which trapped air is removed from the apical region of simulated root canals by activation of an irrigant using an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser during endodontic procedures. A high-speed imaging system with high temporal and spatial resolution was used to visualize laser-induced shock waves in a resin block model with a curved root canal (inner diameter at the apex 0.08 mm, taper 4 %, crown height 10 mm, overall length 40 mm) and a glass cylinder model with a straight root canal (inner diameter 1 mm, crown height 10 mm, overall length 40 mm). The study utilized MZ3 and RFT3 tips in each model, without water or air spray, and with an average power of 1 W at 35 Hz. Laser-activated irrigation overcame the airlock effect by releasing air trapped in the air column. The mechanism underlying the removal of trapped air from the apical region using an Er,Cr:YSGG laser in a dry root canal is via the disruption of the surface tension at the solution-air interface. This disruption, caused by bubble implosion (cavitation), displaces air in the form of bubbles from the apical region toward the solution, which allows the solution to travel apically.

  8. Simulating the value of El Niño forecasts for the Panama Canal

    NASA Astrophysics Data System (ADS)

    Graham, Nicholas E.; Georgakakos, Konstantine P.; Vargas, Carlos; Echevers, Modesto

    2006-11-01

    The Panama Canal relies on rain-fed streamflow into Gatun Lake, the canal's primary storage facility, for operations—principally ship passage and hydropower generation. Precipitation in much of Panama has a strong negative relationship with eastern tropical Pacific sea surface temperature (SST) and this relationship is reflected in Gatun Lake inflows. For example, the correlation coefficient between wet season (July-December) inflow and NINO3 SST is -0.53 over the period 1914-1997. Operational capabilities to predict tropical Pacific SSTs have been demonstrated by several forecast systems during the past decade, and (as we show) such SST forecasts can be used to reduce the uncertainty of estimates of future inflows (compared with climatological expectations). Because substantial reductions in lake inflow negatively impact canal operations, we wondered whether these forecasts of future inflows, coupled with a method for translating that information into effective operational policy, might result in more efficient canal management. A combined simulation/optimization/assessment "virtual" canal system was implemented and exercised using operational El Niño forecasts over the period 1981-1998. The results show the following main points: At current demand levels, the canal system is relatively robust (insensitive to flow forecasts) unless flows are substantially reduced (i.e., during El Niño episodes) or forecasts are extremely accurate. The inclusion of accurately specified levels of forecast uncertainty is critical in developing economically beneficial policies. The situations in which imperfect forecast information can be useful lie between those where storage and future inflows are relatively high, and those where storage and inflows are relatively low. In the former case, demands can be met without the benefit of forecast information, and in the latter case even perfect forecast information cannot prevent operational curtailments. For a nominally configured

  9. Simulation of the effects of proposed tide gates on circulation, flushing, and water quality in residential canals, Cape Coral Florida

    USGS Publications Warehouse

    Goodwin, Carl R.

    1991-01-01

    Decades of dredging and filling of Florida's low-lying coastal wetlands have produced thousands of miles of residential tidal canals and adjacent waterfront property. Typically, these canals are poorly flushed, and over time, accumulated organic-rich bottom materials, contribute to an increasingly severe degraded water quality. One-dimensional hydrodynamic and constituent-transport models were applied to two dead-end canal systems to determine the effects of canal system interconnection using tide gates on water circulation and constituent flushing. The model simulates existing and possible future circulation and flushing conditions in about 29 miles of the approximately 130 miles of tidally influenced canals in Cape Coral, located on the central west coast of peninsular Florida. Model results indicate that tidal water-level differences between the two canal systems can be converted to kinetic energy, in the form of increased water circulation, but the use of one-way tide gate interconnections. Computations show that construction of from one to four tide gates will cause replacement of a volume of water equivalent to the total volume of canals in both systems in 15 to 9 days, respectively. Because some canals flush faster than others, 47 and 21 percent of the original canal water will remain in both systems 50 days after start of operation of one and four tide gates, respectively. Some of the effects that such increased flushing are expected to have include reduced density stratification and associated dissolved-oxygen depletion in canal bottom waters, increased localized reaeration, and more efficient discharge of stormwater runoff entering the canals.

  10. Shaping ability of three ProFile rotary instrumentation techniques in simulated resin root canals.

    PubMed

    Kum, K Y; Spängberg, L; Cha, B Y; Il-Young, J; Msd; Seung-Jong, L; Chan-Young, L

    2000-12-01

    The aim of this study was to compare the shaping ability of three ProFile rotary instrumentation techniques and a conventional step-back method in simulated root canals. Prevalence of canal aberrations, change in working length, and preparation time were measured. A total of 48 composite images were made from pre- and postcanal scanned images using Corel Photopaint 8.0 and then the amount of coronal substance the instruments removed was also calculated two-dimensionally on digitized images with the Brain C software to compare the enlarging efficiency. There were no significant differences between the three rotary groups in preparation time, change in working length, and the incidence of aberrations (p > 0.05). The amount of coronal substance the instruments removed in the ProFile .04 taper group was significantly smaller than the other three groups (p < 0.05).

  11. Apical transportation associated with ProTaper® Universal F1, F2 and F3 instruments in curved canals prepared by undergraduate students

    PubMed Central

    BRITO-JÚNIOR, Manoel; FARIA-E-SILVA, André Luis; CAMILO, Carla Cristina; PEREIRA, Rodrigo Dantas; BRAGA, Neilor Mateus Antunes; SOUSA-NETO, Manoel Damião

    2014-01-01

    Objective This study evaluated apical transportation associated with ProTaper® Universal Fl, F2 and F3 rotary files in curved canais prepared by undergraduate students. Material and Methods Twenty mesial roots of mandibular molars with curvatures ranging between 25° and 35° were selected. Mesiobuccal canals were instrumented by twenty students with the ProTaper® system (Dentsply-Maillefer, Ballaigues, Switzerland) according to the manufacturer's instructions. Pre-fiaring was performed with Sl and SX files. A #15 K-file was inserted into the root canal up to the working length (WL), and an initial digital radiograph was taken in a buccolingual direction (baseline). Afterwards, the S1, S2, F1, F2, and F3 files were employed up to the WL. Other radiographies were taken in the same orientation of the baseline after the use of the Fl, F2, and F3 files, with each file inserted into the root canal. The radiographic images were overlapped, and the Image J software was used to measure the distance between the rotary files' ends and the #15 K-file's end, characterizing the apical transportation. Data were analyzed by Repeated Measure ANOVA and by the SNK post hoc test (P<0.05). Results It was verified that file size affected apical transportation significantly (P<0.001). The F3 file showed higher apical transportation than Fl and F2, while between these last files there was no difference. Conclusion The undergraduate students produced lower apical transportation in curved canals when they did not use the F3 rotary file. PMID:24676579

  12. Effectiveness of Four Different Final Irrigation Activation Techniques on Smear Layer Removal in Curved Root Canals : A Scanning Electron Microscopy Study

    PubMed Central

    Ahuja, Puneet; Nandini, Suresh; Ballal, Suma; Velmurugan, Natanasabapathy

    2014-01-01

    Objective: The aim of this study was to assess the efficacy of apical negative pressure (ANP), manual dynamic agitation (MDA), passive ultrasonic irrigation (PUI) and needle irrigation (NI) as final irrigation activation techniques for smear layer removal in curved root canals. Materials and Methods: Mesiobuccal root canals of 80 freshly extracted maxillary first molars with curvatures ranging between 25° and 35° were used. A glide path with #08–15 K files was established before cleaning and shaping with Mtwo rotary instruments (VDW, Munich, Germany) up to size 35/0.04 taper. During instrumentation, 1 ml of 2.5% NaOCl was used at each change of file. Samples were divided into 4 equal groups (n=20) according to the final irrigation activation technique: group 1, apical negative pressure (ANP) (EndoVac); group 2, manual dynamic agitation (MDA); group 3, passive ultrasonic irrigation (PUI); and group 4, needle irrigation (NI). Root canals were split longitudinally and subjected to scanning electron microscopy. The presence of smear layer at coronal, middle and apical levels was evaluated by superimposing 300-μm square grid over the obtained photomicrographs using a four-score scale with X1,000 magnification. Results: Amongst all the groups tested, ANP showed the overall best smear layer removal efficacy (p < 0.05). Removal of smear layer was least effective with the NI technique. Conclusion: ANP (EndoVac system) can be used as the final irrigation activation technique for effective smear layer removal in curved root canals. PMID:24910670

  13. Simulated Performance of Timescale Metrics for Aperiodic Light Curves

    NASA Astrophysics Data System (ADS)

    Findeisen, Krzysztof; Cody, Ann Marie; Hillenbrand, Lynne

    2015-01-01

    Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time-domain surveys, it is increasingly essential to develop methods to quantify and analyze aperiodic variability. We develop three timescale metrics that have been little used in astronomy—Δm-Δt plots, peak-finding, and Gaussian process regression—and present simulations comparing their effectiveness across a range of aperiodic light curve shapes, characteristic timescales, observing cadences, and signal to noise ratios. We find that Gaussian process regression is easily confused by noise and by irregular sampling, even when the model being fit reflects the process underlying the light curve, but that Δm-Δt plots and peak-finding can coarsely characterize timescales across a broad region of parameter space. We make public the software we used for our simulations, both in the spirit of open research and to allow others to carry out analogous simulations for their own observing programs.

  14. SIMULATED PERFORMANCE OF TIMESCALE METRICS FOR APERIODIC LIGHT CURVES

    SciTech Connect

    Findeisen, Krzysztof; Hillenbrand, Lynne; Cody, Ann Marie

    2015-01-10

    Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time-domain surveys, it is increasingly essential to develop methods to quantify and analyze aperiodic variability. We develop three timescale metrics that have been little used in astronomy—Δm-Δt plots, peak-finding, and Gaussian process regression—and present simulations comparing their effectiveness across a range of aperiodic light curve shapes, characteristic timescales, observing cadences, and signal to noise ratios. We find that Gaussian process regression is easily confused by noise and by irregular sampling, even when the model being fit reflects the process underlying the light curve, but that Δm-Δt plots and peak-finding can coarsely characterize timescales across a broad region of parameter space. We make public the software we used for our simulations, both in the spirit of open research and to allow others to carry out analogous simulations for their own observing programs.

  15. Histological evaluation of the cleaning effectiveness of two reciprocating single-file systems in severely curved root canals: Reciproc versus WaveOne

    PubMed Central

    Carvalho, Maira de Souza; Junior, Emílio Carlos Sponchiado; Bitencourt Garrido, Angela Delfina; Roberti Garcia, Lucas da Fonseca; Franco Marques, André Augusto

    2015-01-01

    Objective: The aim of this study was to evaluate the cleaning effectiveness achieved with two reciprocating single-file systems in severely curved root canals: Reciproc and WaveOne. Materials and Methods: Twenty-five mesial roots of mandibular molars were randomly separated into two groups, according to the instrumentation system used. The negative control group consisted of five specimens that were not instrumented. The mesial canals (buccal and lingual) in Reciproc Group were instrumented with file R25 and the WaveOne group with the Primary file. The samples were submitted to histological processing and analyzed under a digital microscope. Results: The WaveOne group presented a larger amount of debris than the Reciproc Group, however, without statistically significant difference (P > 0.05). A larger amount of debris in the control group was observed, with statistically significant difference to Reciproc and WaveOne groups (P < 0.05). Conclusions: The two reciprocating single-file instrumentation systems presented similar effectiveness for root canal cleaning. PMID:25713489

  16. Removal of Gutta-Percha/Zinc-Oxide-Eugenol Sealer or Gutta-Percha/Epoxy Resin Sealer from Severely Curved Canals: An In Vitro Study

    PubMed Central

    Reddy, Santhoshini; Neelakantan, Prasanna; Saghiri, Mohammad Ali; Lotfi, Mehrdad; Subbarao, Chandragiri Venkata; Garcia-Godoy, Franklin; Gutmann, James L.

    2011-01-01

    The aim of this study was to compare the cleanliness of root canal walls after retreatment using two rotary retreatment files to hand instruments in severely curved canals obturated with gutta-percha and two different sealers. Single rooted mandibular premolars (n = 90) with root curvatures were instrumented and obturated with gutta-percha and an epoxy resin (Group 1, n = 45) or zinc oxide eugenol sealer (Group 2, n = 45). Following retreatment of the specimens (n = 15 ProTaper Universal Retreatment Files (Subgroup B) or R-Endo retreatment files (Subgroup C) after 1 month, split specimens were examined under a stereomicroscope and the percentage of remaining root filling material was statistically compared using one way ANOVA with Bonferroni adjustment for multiple comparisons (P = 0.05). The R-Endo system performed significantly better than the other two file systems (P < 0.05). None of the systems used in this study cleaned root canals thoroughly. The R-Endo system did provide cleaner walls when compared to the other instruments used. The type of root filling materials had an impact on the outcomes with all techniques. PMID:22145001

  17. Scanning Electron Microscopic Evaluation of Residual Smear Layer Following Preparation of Curved Root Canals Using Hand Instrumentation or Two Engine-Driven Systems

    PubMed Central

    Khademi, Abbasali; Saatchi, Masoud; Shokouhi, Mohammad Mehdi; Baghaei, Badri

    2015-01-01

    Introduction: In this experimental study, the amount of smear layer (SL) remnants in curved root canals after chemomechanical instrumentation with two engine-driven systems or hand instrumentation was evaluated. Methods and Materials: Forty-eight mesiobuccal roots of mandibular first molars with curvatures ranging between 25 and 35 degrees (according to Schneider’s method) were divided into three groups (n=16) which were prepared by either the ProTaper Universal file series, Reciproc single file system or hand instrumentation. The canals were intermittently irrigated with 5.25% NaOCl and 17% (ethylenediaminetetraacetic acid) EDTA, followed by distilled water as the final rinse. The roots were split longitudinally and the apical third of the specimens were evaluated under 2500× magnification with a scanning electron microscope (SEM). The mean scores of the SL were calculated and analyzed using the non-parametric Kruskal-Wallis and Mann-Whitney U tests. Results: The mean scores of the SL were 2.00±0.73, 1.94±0.68 and 1.44±0.63 µm for the ProTaper Universal, Reciproc and hand instrumentation, respectively. Mean score of SL was significantly less in the hand instrumentation group than the ProTaper (P=0.027) and Reciproc (P=0.035) groups. The difference between the two engine-driven systems, however, was not significant (P=0.803). Conclusion: The amount of smear layer in the apical third of curved root canals prepared with both engine-driven systems was similar and greater than the hand instrumentation technique. Complete cleanliness was not attained. PMID:26523137

  18. Simulations of (An)Isotropic Diffusion on Curved Biological Surfaces

    PubMed Central

    Sbalzarini, Ivo F.; Hayer, Arnold; Helenius, Ari; Koumoutsakos, Petros

    2006-01-01

    We present a computational particle method for the simulation of isotropic and anisotropic diffusion on curved biological surfaces that have been reconstructed from image data. The method is capable of handling surfaces of high curvature and complex shape, which are often encountered in biology. The method is validated on simple benchmark problems and is shown to be second-order accurate in space and time and of high parallel efficiency. It is applied to simulations of diffusion on the membrane of endoplasmic reticula (ER) in live cells. Diffusion simulations are conducted on geometries reconstructed from real ER samples and are compared to fluorescence recovery after photobleaching experiments in the same ER samples using the transmembrane protein tsO45-VSV-G, C-terminally tagged with green fluorescent protein. Such comparisons allow derivation of geometry-corrected molecular diffusion constants for membrane components from fluorescence recovery after photobleaching data. The results of the simulations indicate that the diffusion behavior of molecules in the ER membrane differs significantly from the volumetric diffusion of soluble molecules in the lumen of the same ER. The apparent speed of recovery differs by a factor of ∼4, even when the molecular diffusion constants of the two molecules are identical. In addition, the specific shape of the membrane affects the recovery half-time, which is found to vary by a factor of ∼2 in different ER samples. PMID:16284262

  19. Simulations of (an)isotropic diffusion on curved biological surfaces.

    PubMed

    Sbalzarini, Ivo F; Hayer, Arnold; Helenius, Ari; Koumoutsakos, Petros

    2006-02-01

    We present a computational particle method for the simulation of isotropic and anisotropic diffusion on curved biological surfaces that have been reconstructed from image data. The method is capable of handling surfaces of high curvature and complex shape, which are often encountered in biology. The method is validated on simple benchmark problems and is shown to be second-order accurate in space and time and of high parallel efficiency. It is applied to simulations of diffusion on the membrane of endoplasmic reticula (ER) in live cells. Diffusion simulations are conducted on geometries reconstructed from real ER samples and are compared to fluorescence recovery after photobleaching experiments in the same ER samples using the transmembrane protein tsO45-VSV-G, C-terminally tagged with green fluorescent protein. Such comparisons allow derivation of geometry-corrected molecular diffusion constants for membrane components from fluorescence recovery after photobleaching data. The results of the simulations indicate that the diffusion behavior of molecules in the ER membrane differs significantly from the volumetric diffusion of soluble molecules in the lumen of the same ER. The apparent speed of recovery differs by a factor of approximately 4, even when the molecular diffusion constants of the two molecules are identical. In addition, the specific shape of the membrane affects the recovery half-time, which is found to vary by a factor of approximately 2 in different ER samples.

  20. Irrigation Management, Evolving Canal Systems and Social Simulation in Hohokam Society, Central Arizona

    NASA Astrophysics Data System (ADS)

    Ertsen, Maurits; Murphy, John; Purdue, Louise

    2015-04-01

    As may societies that rely on irrigation, the Hohokam civilization in South West Arizona faced challenges arising from the variability and unpredictability of water supply and the physics underlying the flow of water through open channels. Such challenges can be overcome through cooperation and other forms of structured social interactions and institutions ranging from simple to complex. These interactions are influenced by and are influenced themselves by environmental conditions, including hydrology, soils and vegetation. At the same time, the environmental record provides clues to these interactions. To better understand these past interactions we combine geoarchaeological studies with flow simulations and Agent Based Modeling. Fieldwork conducted on Hohokam irrigation revealed new details about canal morphology, including shape, size, elevation, slope, and cleaning events. Micromorphological study of the sediments in these structures allow finer resolution in discerning the performance (velocity, discharge, etc.) of the canal channels and their evolution through time. We couple this with basic agent-based modeling to explore how these constraints might have required alternative strategies for cooperation. The combination of both approaches is key to discerning both broad differences between periods and fine variation within major chronological periods. We show that the coupling of social and physical models on very fine time scales can offer insight into the social arrangements and day-to-day life of people in the prehistoric past and inform our understanding of those societies' long-term changes.

  1. The reamer/irrigator/aspirator reduces femoral canal pressure in simulated TKA.

    PubMed

    Van Gorp, Cornel C; Falk, James V; Kmiec, Stanley J; Siston, Robert A

    2009-03-01

    Inserting the femoral intramedullary alignment rod during total knee arthroplasty (TKA) can generate high intramedullary pressure, which increases the risk of intraoperative complications caused by fat embolism. Despite modifications to the surgical procedure, the best method to prevent this increase in pressure remains unknown. The reamer/irrigator/aspirator is a surgical instrument designed for use during femoral canal entry to increase the canal size and remove intramedullary fat and may prevent this pressure increase. We posed two hypotheses: (1) using the reamer/irrigator/aspirator system will result in lower maximum femoral intramedullary pressure than using only conventional instrumentation during the initial steps of a TKA; and (2) using the reamer/irrigator/aspirator system in the initial steps of TKA will result in a mean maximum intramedullary pressure less than 200 mm Hg. We simulated a TKA on 14 cadaveric femurs to compare the femoral intramedullary pressure using both methods. Considerable decreases in femoral intramedullary pressure of 86% proximally and 87% distally were obtained by using the reamer/irrigator/aspirator system. The mean maximum pressure using the reamer/irrigator/aspirator system was less than 200 mm Hg. Additional clinical studies are needed to confirm any reduction in complications using the reamer/irrigator/aspirator system.

  2. The Reamer/Irrigator/Aspirator Reduces Femoral Canal Pressure in Simulated TKA

    PubMed Central

    Van Gorp, Cornel C.; Falk, James V.; Kmiec, Stanley J.

    2008-01-01

    Inserting the femoral intramedullary alignment rod during total knee arthroplasty (TKA) can generate high intramedullary pressure, which increases the risk of intraoperative complications caused by fat embolism. Despite modifications to the surgical procedure, the best method to prevent this increase in pressure remains unknown. The reamer/irrigator/aspirator is a surgical instrument designed for use during femoral canal entry to increase the canal size and remove intramedullary fat and may prevent this pressure increase. We posed two hypotheses: (1) using the reamer/irrigator/aspirator system will result in lower maximum femoral intramedullary pressure than using only conventional instrumentation during the initial steps of a TKA; and (2) using the reamer/irrigator/aspirator system in the initial steps of TKA will result in a mean maximum intramedullary pressure less than 200 mm Hg. We simulated a TKA on 14 cadaveric femurs to compare the femoral intramedullary pressure using both methods. Considerable decreases in femoral intramedullary pressure of 86% proximally and 87% distally were obtained by using the reamer/irrigator/aspirator system. The mean maximum pressure using the reamer/irrigator/aspirator system was less than 200 mm Hg. Additional clinical studies are needed to confirm any reduction in complications using the reamer/irrigator/aspirator system. PMID:18425558

  3. SHG simulations of plasmonic nanoparticles using curved elements.

    PubMed

    Kullock, René; Hille, Andreas; Haussmann, Alexander; Grafström, Stefan; Eng, Lukas M

    2011-07-18

    We demonstrate that simulating plasmonic nanostructures by means of curved elements (CEs) significantly increases the accuracy and computation speed not only in the linear but also in the nonlinear regime. We implemented CEs within the discontinuous Galerkin (DG) method and, as an example of a nonlinear effect, investigated second-harmonic generation (SHG) at a silver nanoparticle. The second-harmonic response of the material is simulated by an extended Lorentz model (ELM). In the linear regime the CEs are ≈ 9 times faster than ordinary elements for the same accuracy, provide a much better convergence and show fewer unphysical field artifacts. For DG-SHG calculations CEs are almost indispensable to obtain physically reasonable results at all. Additionally, their boundary approximation has to be of the same order as their polynomial degree to achieve artifact-free field distributions. In return, the use of such CEs with the DG method pays off more than evidently, since the additional computation time is only 1%.

  4. Shaping ability of Reciproc and TF Adaptive systems in severely curved canals of rapid microCT-based prototyping molar replicas

    PubMed Central

    ORDINOLA-ZAPATA, Ronald; BRAMANTE, Clovis Monteiro; DUARTE, Marco Antonio Húngaro; CAVENAGO, Bruno Cavalini; JARAMILLO, David; VERSIANI, Marco Aurélio

    2014-01-01

    Objective: To evaluate the shaping ability of Reciproc and Twisted-File Adaptive systems in rapid prototyping replicas. Material and Methods: Two mandibular molars showing S-shaped and 62-degree curvatures in the mesial root were scanned by using a microcomputed tomography (μCT) system. The data were exported in the stereolitograhic format and 20 samples of each molar were printed at 16 µm resolution. The mesial canals of 10 replicas of each specimen were prepared with each system. Transportation was measured by overlapping radiographs taken before and after preparation and resin thickness after instrumentation was measured by μCT. Results: Both systems maintained the original shape of the apical third in both anatomies (P>0.05). Overall, considering the resin thickness in the 62-degree replicas, no statistical difference was found between the systems (P>0.05). In the S-shaped curvature replica, Reciproc significantly decreased the thickness of the resin walls in comparison with TF Adaptive. Conclusions: The evaluated systems were able to maintain the original shape at the apical third of severely curved mesial canals of molar replicas. PMID:24918662

  5. Alterations of the Danger Zone after Preparation of Curved Root Canals Using WaveOne with Reverse Rotation or Reciprocation Movements

    PubMed Central

    Shantiaee, Yazdan; Dianat, Omid; Paymanpour, Payam; Nahvi, Golnaz; Ketabi, Mohammad Ali; Kolahi Ahari, Golbarg

    2015-01-01

    Introduction: The aim of this study was to compare the changes that occur in the danger zone (DZ) after preparation of curved mesiobuccal (MB) canals of mandibular first molars with WaveOne instruments in two different movements [reciprocation (RCP) and counter-clockwise rotation (CCWR)] by means of cone-beam computed tomography (CBCT). Methods and Materials: MB canals of 30 mandibular molars were randomly divided into 2 groups (n=15); WaveOne/RCP and WaveOne/CCWR. Pre- and post-instrumentation CBCT images were assessed for changes in the dentin thickness in DZ (2 and 4 mm below the highest point of the root furcation) in both groups. Data was analyzed using the repeated measures ANOVA test. Results: There was no statistically significant difference between two experimental groups in terms of remaining dentin thickness at 2 and 4 mm levels below the highest point of the furcation (P>0.05). Conclusion: The efficacy of WaveOne instrument on changes of the dentin thickness in the DZ was not affected by different file movements. PMID:26213536

  6. Simulating cartilage conduction sound to estimate the sound pressure level in the external auditory canal

    NASA Astrophysics Data System (ADS)

    Shimokura, Ryota; Hosoi, Hiroshi; Nishimura, Tadashi; Iwakura, Takashi; Yamanaka, Toshiaki

    2015-01-01

    When the aural cartilage is made to vibrate it generates sound directly into the external auditory canal which can be clearly heard. Although the concept of cartilage conduction can be applied to various speech communication and music industrial devices (e.g. smartphones, music players and hearing aids), the conductive performance of such devices has not yet been defined because the calibration methods are different from those currently used for air and bone conduction. Thus, the aim of this study was to simulate the cartilage conduction sound (CCS) using a head and torso simulator (HATS) and a model of aural cartilage (polyurethane resin pipe) and compare the results with experimental ones. Using the HATS, we found the simulated CCS at frequencies above 2 kHz corresponded to the average measured CCS from seven subjects. Using a model of skull bone and aural cartilage, we found that the simulated CCS at frequencies lower than 1.5 kHz agreed with the measured CCS. Therefore, a combination of these two methods can be used to estimate the CCS with high accuracy.

  7. Direct numerical simulation of curved turbulent channel flow

    NASA Technical Reports Server (NTRS)

    Moser, R. D.; Moin, P.

    1984-01-01

    Low Reynolds number, mildly curved, turbulent channel flow has been simulated numerically without subgrid scale models. A new spectral numerical method developed for this problem was used, and the computations were performed with 2 million degrees of freedom. A variety of statistical and structural information has been extracted from the computed flow fields. These include mean velocity, turbulence stresses, velocity skewness, and flatness factors, space time correlations and spectra, all the terms in the Reynolds stress balance equations, and contour and vector plots of instantaneous velocity fields. The effects of curvature on this flow were determined by comparing the concave and convex sides of the channel. The observed effects are consistent with experimental observations for mild curvature. The most significant difference in the turbulence statistics between the concave and convex sides was in the Reynolds shear stress. This was accompanied by significant differences in the terms of the Reynolds shear stress balance equations. In addition, it was found that stationary Taylor-Gortler vortices were present and that they had a significant effect on the flow by contributing to the mean Reynolds shear stress, and by affecting the underlying turbulence.

  8. Mechanical Behavior of a NiTi Endodontic File During Insertion in an Anatomic Root Canal Using Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Legrand, V.; Moyne, S.; Pino, L.; Arbab Chirani, S.; Calloch, S.; Chevalier, V.; Arbab Chirani, R.

    2015-12-01

    Superelastic NiTi shape memory alloys (SMA) have biomedical applications including rotary endodontic files. These alloys are used thanks to their flexibility, which is due to solid-solid martensitic transformation. Unfortunately, the intracanal file separation can occur during canal preparation. To avoid this problem and to have a good idea of the mechanical behavior of these instruments, finite elements simulations taking into account the real shape of root canals are proposed in this study. This is possible by using a well-adapted model describing all the particularities of SMA and representative limit conditions. The behavior model has been validated in previous studies under complex loadings. It is implemented in ABAQUS® finite elements software. The anatomic shapes of root canals are extracted by microtomography using a real tooth. They are applied as limit conditions in realized simulations to be as near as possible to clinical conditions. The mechanical behavior of an endodontic file is then simulated during insertion in a root canal without and with rotation. This permits to obtain different information like the loading applied to the instrument during its use, the stress, and the phase transformation fields through the file. This is useful not only for clinical use but also for new NiTi endodontic instruments design.

  9. Simulations of curved assemblies in soft matter and biological systems

    NASA Astrophysics Data System (ADS)

    Qiao, Cong

    Viruses are small infectious agents that replicate only inside living cells of other organisms. In the viral life cycle, the self-assembly of the outer protein shell (capsid) is an essential step. We study this process in the hope of shedding light on development of antiviral drugs, gene therapy and other virus-related technologies that can benefit the humankind. More fundamentally, learning about the process of viral capsid assembly can elucidate the assembly mechanisms of a wide range of complex structures. In this work, we use molecular dynamics simulations and coarse-grained computational models to study viral capsid assembly in several situations where geometric constraints play a role in dictating assembly outcomes. We first focus on icosahedral viruses with single-stranded RNA genomes, in which case the capsid usually assembles around the genomic RNA. It is consistently observed in experiments that such viral particles are ''overcharged'', meaning the net negative charge on the viral genome is greater than the net positive charge on the viral capsid. We computationally investigate the mechanisms that lead to ``overcharging'', and more broadly, how the encapsidated genome length is influenced by the capsid. We perform both dynamical simulations of the assembly process and equilibrium calculations to determine the optimal genome length (meaning that which maximizes the assembly yield and/or minimizes the free energy of the assembled virus). We find that the optimal genome length is determined by the interplay between capsid size, net capsid charge, distribution of capsid charge and nucleic acid structures. Our simulations demonstrate that overcharging results from a combination of electrostatic screening and the geometric constraints associated with encapsulating a nucleic acid inside of a spherical virus. We then study the assembly of the immature HIV. In contrast to icosahedral viruses, the immature HIV forms an asymmetric particle, consisting of continuous

  10. Reconstruction of quadratic curves in 3D using two or more perspective views: simulation studies

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjeev; Sukavanam, N.; Balasubramanian, R.

    2006-01-01

    The shapes of many natural and man-made objects have planar and curvilinear surfaces. The images of such curves usually do not have sufficient distinctive features to apply conventional feature-based reconstruction algorithms. In this paper, we describe a method of reconstruction of a quadratic curve in 3-D space as an intersection of two cones containing the respective projected curve images. The correspondence between this pair of projections of the curve is assumed to be established in this work. Using least-square curve fitting, the parameters of a curve in 2-D space are found. From this we are reconstructing the 3-D quadratic curve. Relevant mathematical formulations and analytical solutions for obtaining the equation of reconstructed curve are given. The result of the described reconstruction methodology are studied by simulation studies. This reconstruction methodology is applicable to LBW decision in cricket, path of the missile, Robotic Vision, path lanning etc.

  11. Shaping ability of reciprocating motion of WaveOne and HyFlex in moderate to severe curved canals: A comparative study with cone beam computed tomography

    PubMed Central

    Simpsy, Gurram Samuel; Sajjan, Girija S.; Mudunuri, Padmaja; Chittem, Jyothi; Prasanthi, Nalam N. V. D.; Balaga, Pankaj

    2016-01-01

    Introduction: M-Wire and reciprocating motion of WaveOne and controlled memory (CM) wire) of HyFlex were the recent innovations using thermal treatment. Therefore, a study was planned to evaluate the shaping ability of reciprocating motion of WaveOne and HyFlex using cone beam computed tomography (CBCT). Methodology: Forty-five freshly extracted mandibular teeth were selected and stored in saline until use. All teeth were scanned pre- and post-operatively using CBCT (Kodak 9000). All teeth were accessed and divided into three groups. (1) Group 1 (control n = 15): Instrumented with ProTaper. (2) Group 2 (n = 15): Instrumented with primary file (8%/25) WaveOne. (3) Group 3 (n = 15): Instrumented with (4%/25) HyFlex CM. Sections at 1, 3, and 5 mm were obtained from the pre- and post-operative scans. Measurement was done using CS3D software and Adobe Photoshop software. Apical transportation and degree of straightening were measured and statistically analyzed. Results: HyFlex showed lesser apical transportation when compared to other groups at 1 and 3 mm. WaveOne showed lesser degree of straightening when compared to other groups. Conclusion: This present study concluded that all systems could be employed in routine endodontics whereas HyFlex and WaveOne could be employed in severely curved canals. PMID:27994323

  12. Photodynamic Inactivation of Root Canal Bacteria by Light Activation through Human Dental Hard and Simulated Surrounding Tissue

    PubMed Central

    Cieplik, Fabian; Pummer, Andreas; Leibl, Christoph; Regensburger, Johannes; Schmalz, Gottfried; Buchalla, Wolfgang; Hiller, Karl-Anton; Maisch, Tim

    2016-01-01

    Introduction: Photodynamic inactivation of bacteria (PIB) may be a supportive antimicrobial approach for use in endodontics, but sufficient activation of photosensitizers (PS) in root canals is a critical point. Therefore, aim of this study was to evaluate the ability of PS absorbing blue (TMPyP) or red light (Methylene Blue; MB) for light activation through human dental hard and simulated surrounding tissue to inactivate root canal bacteria. Methods: A tooth model was fabricated with a human premolar and two molars in an acrylic resin bloc simulating the optical properties of a porcine jaw. The distal root canal of the first molar was enlarged to insert a glass tube (external diameter 2 mm) containing PS and stationary-phase Enterococcus faecalis. Both PS (10 μM) were irradiated for 120 s with BlueV (20 mW/cm2; λem = 400–460 nm) or PDT 1200L (37.8 mW/cm2; λem = 570–680 nm; both: Waldmann Medizintechnik), respectively. Irradiation parameters ensured identical numbers of photons absorbed by each PS. Three setups were chosen: irradiating the glass pipette only (G), the glass pipette inside the single tooth without (GT) and with (GTM) simulated surrounding tissues. Colony forming units (CFU) were evaluated. Transmission measurements of the buccal halves of hemisected mandibular first molars were performed by means of a photospectrometer. Results: PIB with both PS led to reduction by ≥ 5 log10 of E. faecalis CFU for each setup. From transmission measurements, a threshold wavelength λth for allowing an amount of light transmission for sufficient activation of PS was determined to be 430 nm. Conclusion: This study can be seen as proof of principle that light activation of given intra-canal PS from outside a tooth may be possible at wavelengths ≥ 430 nm, facilitating clinical application of PIB in endodontics. PMID:27379059

  13. Numerical Simulation of Ballistic Limit Curves for Orbital Debris Shielding.

    DTIC Science & Technology

    1998-05-01

    conducted to evaluate the use of this new code for orbital debris shielding design. Two sets of simulations, one for a single bumper Whipple shield and...experiment. The results show that EXOS provides an accurate and computationally tractable approach to simulate orbital debris shield performance.

  14. A Comparative SEM Investigation of Smear Layer Remaining on Dentinal Walls by Three Rotary NiTi Files with Different Cross Sectional Designs in Moderately Curved Canals

    PubMed Central

    Kakkar, Pooja; Vats, Asit

    2015-01-01

    Objective: The objective of this study was to compare the smear layer formed on root canal walls during canal preparation of extracted human teeth by Twisted, Mtwo, and ProTaper rotary nickel titanium instruments. Materials and Methods: Sixty single rooted human premolar teeth with root curvature <250 were selected and randomly divided into three Groups (n= 20 teeth per Group). Three types of rotary nickel titanium instruments were used, Twisted (SybronEndo, Orange, CA, USA), Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) according to manufacturer’s instructions to instrument the root canals. Irrigation for all groups was performed after each instrument change with 3ml of 3% sodium hypochlorite followed by Glyde (File Prep, Dentsply, Maillefer, Ballaigues, Switzerland) as chelator paste and lubricant. Three different areas (coronal, middle and apical thirds) of the root canal were evaluated using scanning electron microscopy (SEM). The canal wall of each sample was assessed and compared using a predefined scale for the presence or absence of smear layer. Data were analysed statistically using ANOVA and Tukey HSD test Results: All three groups showed statistically significant more smear layer in the apical thirds of the canal as compared to the coronal and middle thirds (p<0.001). Mtwo rotary file system produced significantly less smear layer (p<0.001) compared to Twisted and ProTaper rotary instruments in the apical portion. Twisted Files resulted in less smear layer formation in the apical thirds of the canal compared to ProTaper rotary instruments but were statistically insignificant. Conclusion: Completely clean root canals were not found after instrumentation with any of the three instruments. Under the confines of this study Mtwo instruments produced significantly cleaner dentin wall surfaces throughout the canal length in comparison to Twisted and ProTaper rotary files. Twisted Files proved to be comparable to Pro

  15. An improved algorithm of three B-spline curve interpolation and simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Wanjun; Xu, Dongmei; Meng, Xinhong; Zhang, Feng

    2017-03-01

    As a key interpolation technique in CNC system machine tool, three B-spline curve interpolator has been proposed to change the drawbacks caused by linear and circular interpolator, Such as interpolation time bigger, three B-spline curves step error are not easy changed,and so on. This paper an improved algorithm of three B-spline curve interpolation and simulation is proposed. By Using MATALAB 7.0 computer soft in three B-spline curve interpolation is developed for verifying the proposed modification algorithm of three B-spline curve interpolation experimentally. The simulation results show that the algorithm is correct; it is consistent with a three B-spline curve interpolation requirements.

  16. Thermoluminescence curves simulation using genetic algorithm with factorial design

    NASA Astrophysics Data System (ADS)

    Popko, E. A.; Weinstein, I. A.

    2016-05-01

    The evolutionary approach is an effective optimization tool for numeric analysis of thermoluminescence (TL) processes to assess the microparameters of kinetic models and to determine its effects on the shape of TL peaks. In this paper, the procedure for tuning of genetic algorithm (GA) is presented. This approach is based on multifactorial experiment and allows choosing intrinsic mechanisms of evolutionary operators which provide the most efficient algorithm performance. The proposed method is tested by considering the “one trap-one recombination center” (OTOR) model as an example and advantages for approximation of experimental TL curves are shown.

  17. Particle sedimentation in curved tubes: A 3D simulation and optimization for treatment of vestibular vertigo

    NASA Astrophysics Data System (ADS)

    White, Brian; Squires, Todd M.; Hain, Timothy C.; Stone, Howard A.

    2003-11-01

    Benign paroxysmal positional vertigo (BPPV) is a mechanical disorder of the vestibular system where micron-size crystals abnormally drift into the semicircular canals of the inner ear that sense angular motion of the head. Sedimentation of these crystals causes sensation of motion after true head motion has stopped: vertigo results. The usual clinical treatment is through a series of head maneuvers designed to move the particles into a less sensitive region of the canal system. We present a three-dimensional model to simulate treatment of BPPV by determining the complete hydrodynamic motion of the particles through the course of a therapeutic maneuver while using a realistic representation of the actual geometry. Analyses of clinical maneuvers show the parameter range for which they are effective, and indicate inefficiencies in current practice. In addition, an optimization process determines the most effective head maneuver, which significantly differs from those currently in practice.

  18. The Simulation of an Oxidation-Reduction Titration Curve with Computer Algebra

    ERIC Educational Resources Information Center

    Whiteley, Richard V., Jr.

    2015-01-01

    Although the simulation of an oxidation/reduction titration curve is an important exercise in an undergraduate course in quantitative analysis, that exercise is frequently simplified to accommodate computational limitations. With the use of readily available computer algebra systems, however, such curves for complicated systems can be generated…

  19. Panama Canal capacity analysis

    SciTech Connect

    Bronzini, M.S.

    1995-04-27

    Predicting the transit capacities of the various Panama Canal alternatives required analyzing data on present Canal operations, adapting and extending an existing computer simulation model, performing simulation runs for each of the alternatives, and using the simulation model outputs to develop capacity estimates. These activities are summarized in this paper. A more complete account may be found in the project final report (TAMS 1993). Some of the material in this paper also appeared in a previously published paper (Rosselli, Bronzini, and Weekly 1994).

  20. Preparation time and perceptions of Brazilian specialists and dental students regarding simulated root canals for endodontic teaching: a preliminary study.

    PubMed

    dos S Luz, Diandra; de S Ourique, Fernanda; Scarparo, Roberta K; Vier-Pelisser, Fabiana V; Morgental, Renata D; Waltrick, Silvana B G; de Figueiredo, José A P

    2015-01-01

    The aim of this preliminary study was to evaluate the desirability of alternative models of artificial teeth versus extracted natural teeth for use in preclinical dental education. Specifically, the study was designed to compare the preparation time and perceptions of difficulty of undergraduate dental students and endodontists in carrying out root canal preparations on resin models (both clear and opaque) and extracted natural teeth. Twenty participants-ten fifth-year students at a Brazilian dental school and ten endodontists with at least five years' experience in the specialty-performed root canal instrumentation on two samples of each model. Preparation times were recorded, and the participants completed a questionnaire about the anatomical and physical characteristics of these models. The results showed that the time required for performing endodontic procedures in the natural teeth was higher than in the alternative models. The perceptions of the students and specialists regarding some topics on the questionnaire were significantly different. The students had more positive opinions about artificial teeth made of opaque resin, while the specialists had more positive opinions about simulated root canals in clear resin blocks. This study suggests that neither of the alternative models fulfilled requirements to replace natural teeth in endodontic teaching; improvements are still necessary to accomplish this goal.

  1. Modeling and eddy simulation of rotating and curved turbulent flows

    NASA Astrophysics Data System (ADS)

    Arolla, Sunil Kumar

    In the first part of this work, two different approaches to incorporate the effects of rotation and curvature in scalar eddy viscosity models have been explored. One is the "Modified coefficients approach"---to parameterize the model coefficients such that the growth rate of turbulent kinetic energy is suppressed or enhanced. The other is the "Bifurcation approach"---to parameterize eddy-viscosity coefficient such that the equilibrium solution bifurcates from healthy to decaying solution branches. Simple, yet, predictive models in each of these two approaches are proposed and validated on some benchmark test cases characterized by profound effects of system rotation and/or streamline curvature. The results obtained with both the models are encouraging. Application of the models to some practically relevant flow configurations is also discussed. In the second part, a computational framework is developed with recycling and rescaling method of inflow generation to perform eddy simulation of turbomachinery flows. A systematic validation is carried out on a spatially developing boundary layer on flat plate, flow through a channel and an annulus. Then, large eddy simulation of turbine transition duct is performed to demonstrate the effectiveness of this methodology.

  2. Methods for simulating solute breakthrough curves in pumping groundwater wells

    USGS Publications Warehouse

    Starn, J. Jeffrey; Bagtzoglou, Amvrossios C.; Robbins, Gary A.

    2012-01-01

    In modeling there is always a trade-off between execution time and accuracy. For gradient-based parameter estimation methods, where a simulation model is run repeatedly to populate a Jacobian (sensitivity) matrix, there exists a need for rapid simulation methods of known accuracy that can decrease execution time, and thus make the model more useful without sacrificing accuracy. Convolution-based methods can be executed rapidly for any desired input function once the residence-time distribution is known. The residence-time distribution can be calculated efficiently using particle tracking, but particle tracking can be ambiguous near a pumping well if the grid is too coarse. We present several embedded analytical expressions for improving particle tracking near a pumping well and compare them with a finely gridded finite-difference solution in terms of accuracy and CPU usage. Even though the embedded analytical approach can improve particle tracking near a well, particle methods reduce, but do not eliminate, reliance on a grid because velocity fields typically are calculated on a grid, and additional error is incurred using linear interpolation of velocity. A dilution rate can be calculated for a given grid and pumping well to determine if the grid is sufficiently refined. Embedded analytical expressions increase accuracy but add significantly to CPU usage. Structural error introduced by the numerical solution method may affect parameter estimates.

  3. Simulation of a G-tolerance curve using the pulsatile cardiovascular model

    NASA Technical Reports Server (NTRS)

    Solomon, M.; Srinivasan, R.

    1985-01-01

    A computer simulation study, performed to assess the ability of the cardiovascular model to reproduce the G tolerance curve (G level versus tolerance time) is reported. A composite strength duration curve derived from experimental data obtained in human centrifugation studies was used for comparison. The effects of abolishing automomic control and of blood volume loss on G tolerance were also simulated. The results provide additional validation of the model. The need for the presence of autonomic reflexes even at low levels of G is pointed out. The low margin of safety with a loss of blood volume indicated by the simulation results underscores the necessity for protective measures during Shuttle reentry.

  4. Water pollution risk simulation and prediction in the main canal of the South-to-North Water Transfer Project

    NASA Astrophysics Data System (ADS)

    Tang, Caihong; Yi, Yujun; Yang, Zhifeng; Cheng, Xi

    2014-11-01

    The middle route of the South-to-North Water Transfer Project (MRP) will divert water to Beijing Tuancheng Lake from Taocha in the Danjiangkou reservoir located in the Hubei province of China. The MRP is composed of a long canal and complex hydraulic structures and will transfer water in open channel areas to provide drinking water for Beijing, Shijiazhuang and other cities under extremely strict water quality requirements. A large number of vehicular accidents, occurred on the many highway bridges across the main canal would cause significant water pollution in the main canal. To ensure that water quality is maintained during the diversion process, the effects of pollutants on water quality due to sudden pollution accidents were simulated and analyzed in this paper. The MIKE11 HD module was used to calculate the hydraulic characteristics of the 42-km Xishi-to-Beijuma River channel of the MRP. Six types of hydraulic structures, including inverted siphons, gates, highway bridges, culverts and tunnels, were included in this model. Based on the hydrodynamic model, the MIKE11 AD module, which is one-dimensional advection dispersion model, was built for TP, NH3-N, CODMn and F. The validated results showed that the computed values agreed well with the measured values. In accordance with transportation data across the Dianbei Highway Bridge, the effects of traffic accidents on the bridge on water quality were analyzed. Based on simulated scenarios with three discharge rates (ranged from 12 m3/s to 17 m3/s, 40 m3/s, and 60 m3/s) and three pollution loading concentration levels (5 t, 10 t and 20 t) when trucks spill their contents (i.e., phosphate fertilizer, cyanide, oil and chromium solution) into the channel, emergency measures were proposed. Reasonable solutions to ensure the water quality with regard to the various types of pollutants were proposed, including treating polluted water, maintaining materials, and personnel reserves.

  5. Shaping ability of ProTaper NEXT, ProTaper Universal and iRace files in simulated S-shaped canals.

    PubMed

    Hiran-us, Sirawut; Pimkhaokham, Somsinee; Sawasdichai, Jirapat; Ebihara, Arata; Suda, Hideaki

    2016-04-01

    The aim of this study was to determine the shaping ability of three nickel-titanium endodontic file systems by comparing three parameters: canal deviation, apical foramen position and instrumentation time. A glide path was established in 30 simulated S-shaped canal blocks that were randomly assigned into three groups (n = 10): ProTaper Universal, ProTaper NEXT and iRace. Each group was instrumented per its manufacturer's directions. Pre- and postoperative images were superimposed to determine any canal deviation or change in apical foramen position. The instrumentation times were recorded. The iRace system resulted in the least mean canal deviation. The apical foramen position was least shifted by the iRace system. The iRace system also required the least instrumentation time. The iRace system demonstrated the most favourable shaping ability in all three parameters.

  6. On a framework for generating PoD curves assisted by numerical simulations

    SciTech Connect

    Subair, S. Mohamed Agrawal, Shweta Balasubramaniam, Krishnan Rajagopal, Prabhu; Kumar, Anish; Rao, Purnachandra B.; Tamanna, Jayakumar

    2015-03-31

    The Probability of Detection (PoD) curve method has emerged as an important tool for the assessment of the performance of NDE techniques, a topic of particular interest to the nuclear industry where inspection qualification is very important. The conventional experimental means of generating PoD curves though, can be expensive, requiring large data sets (covering defects and test conditions), and equipment and operator time. Several methods of achieving faster estimates for PoD curves using physics-based modelling have been developed to address this problem. Numerical modelling techniques are also attractive, especially given the ever-increasing computational power available to scientists today. Here we develop procedures for obtaining PoD curves, assisted by numerical simulation and based on Bayesian statistics. Numerical simulations are performed using Finite Element analysis for factors that are assumed to be independent, random and normally distributed. PoD curves so generated are compared with experiments on austenitic stainless steel (SS) plates with artificially created notches. We examine issues affecting the PoD curve generation process including codes, standards, distribution of defect parameters and the choice of the noise threshold. We also study the assumption of normal distribution for signal response parameters and consider strategies for dealing with data that may be more complex or sparse to justify this. These topics are addressed and illustrated through the example case of generation of PoD curves for pulse-echo ultrasonic inspection of vertical surface-breaking cracks in SS plates.

  7. On a framework for generating PoD curves assisted by numerical simulations

    NASA Astrophysics Data System (ADS)

    Subair, S. Mohamed; Agrawal, Shweta; Balasubramaniam, Krishnan; Rajagopal, Prabhu; Kumar, Anish; Rao, Purnachandra B.; Tamanna, Jayakumar

    2015-03-01

    The Probability of Detection (PoD) curve method has emerged as an important tool for the assessment of the performance of NDE techniques, a topic of particular interest to the nuclear industry where inspection qualification is very important. The conventional experimental means of generating PoD curves though, can be expensive, requiring large data sets (covering defects and test conditions), and equipment and operator time. Several methods of achieving faster estimates for PoD curves using physics-based modelling have been developed to address this problem. Numerical modelling techniques are also attractive, especially given the ever-increasing computational power available to scientists today. Here we develop procedures for obtaining PoD curves, assisted by numerical simulation and based on Bayesian statistics. Numerical simulations are performed using Finite Element analysis for factors that are assumed to be independent, random and normally distributed. PoD curves so generated are compared with experiments on austenitic stainless steel (SS) plates with artificially created notches. We examine issues affecting the PoD curve generation process including codes, standards, distribution of defect parameters and the choice of the noise threshold. We also study the assumption of normal distribution for signal response parameters and consider strategies for dealing with data that may be more complex or sparse to justify this. These topics are addressed and illustrated through the example case of generation of PoD curves for pulse-echo ultrasonic inspection of vertical surface-breaking cracks in SS plates.

  8. Influence of Operator's Experience on the Shaping Ability of Protaper Universal and Waveone Systems: A Comparative Study on Simulated Root Canals

    PubMed Central

    Troiano, Giuseppe; Dioguardi, Mario; Cocco, Armando; Giannatempo, Giovanni; Laino, Luigi; Ciavarella, Domenico; Berutti, Elio; Lo Muzio, Lorenzo

    2016-01-01

    Objective: To assess the influence of operator experience on: shaping and centering ability, mean preparation time and presence of canal aberrations of ProTaper Universal and WaveOne systems on simulated root canals. Materials and Methods: Sixty S-shaped canals in resin blocks were assigned to four groups (n=15 for each group). Group1 (Experienced operator, ProTaper), Group2 (Experienced operator, WaveOne), Group3 (Inexperienced operator, ProTaper), Group4 (Inexperienced operator, WaveOne). Photographic method was used to record pre- and post-instrumentations images. After superimposition, it has been evaluated presence of canal aberrations and differences in shaping and centering ability between groups. Results: WaveOne system produced a lower amount of canal aberrations both in the hand of expert than inexpert operators. However, a WaveOne instrument breakage occurred in the hands of an inexperienced operator. No differences have been found in the evaluation of shaping ability with both systematics. Operator’s experience doesn't influence the shaping ability of ProTaper and WaveOne systems. Conclusion: Experience factor could influence the centering ability in the use of both the systematics. However, WaveOne Primary reduce the mean preparation time and the presence of canal aberrations. PMID:27843508

  9. GERLUMPH Data Release 2: 2.5 Billion Simulated Microlensing Light Curves

    NASA Astrophysics Data System (ADS)

    Vernardos, G.; Fluke, C. J.; Bate, N. F.; Croton, D.; Vohl, D.

    2015-04-01

    In the upcoming synoptic all-sky survey era of astronomy, thousands of new multiply imaged quasars are expected to be discovered and monitored regularly. Light curves from the images of gravitationally lensed quasars are further affected by superimposed variability due to microlensing. In order to disentangle the microlensing from the intrinsic variability of the light curves, the time delays between the multiple images have to be accurately measured. The resulting microlensing light curves can then be analyzed to reveal information about the background source, such as the size of the quasar accretion disk. In this paper we present the most extensive and coherent collection of simulated microlensing light curves; we have generated \\gt 2.5 billion light curves using the GERLUMPH high resolution microlensing magnification maps. Our simulations can be used to train algorithms to measure lensed quasar time delays, plan future monitoring campaigns, and study light curve properties throughout parameter space. Our data are openly available to the community and are complemented by online eResearch tools, located at http://gerlumph.swin.edu.au.

  10. Digital simulation of scanning electrochemical microscopy approach curves to enzyme films with Michaelis-Menten kinetics.

    PubMed

    Burchardt, Malte; Träuble, Markus; Wittstock, Gunther

    2009-06-15

    The formalism for simulating scanning electrochemical microscopy (SECM) experiments by boundary element methods in three space coordinates has been extended to allow consideration of nonlinear boundary conditions. This is achieved by iteratively refining the boundary conditions that are encoded in a boundary condition matrix. As an example, the simulations are compared to experimental approach curves in the SECM feedback mode toward samples modified with glucose oxidase (GOx). The GOx layer was prepared by the layer-by-layer assembly of polyelectrolytes using glucose oxidase as one of the polyelectrolytes. The comparison of the simulated and experimental curves showed that under a wide range of experimentally accessible conditions approximations of the kinetics at the sample by first order models yield misleading results. The approach curves differ also qualitatively from curves calculated with first order models. As a consequence, this may lead to severe deviations when such curves are fitted to first order kinetic models. The use of linear approximations to describe the enzymatic reaction in SECM feedback experiments is justified only if the ratio of the mediator and Michaelis-Menten constant is equal to or smaller than 0.1 (deviation less than 10%).

  11. Centering Ability of ProTaper Next and WaveOne Classic in J-Shape Simulated Root Canals

    PubMed Central

    Dioguardi, Mario; Cocco, Armando; Giuliani, Michele; Fabiani, Cristiano; D'Alessandro, Alfonso; Ciavarella, Domenico

    2016-01-01

    Introduction. The aim of this study was to evaluate and compare the shaping and centering ability of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) and WaveOne Classic systems (Dentsply Maillefer) in simulated root canals. Methods. Forty J-shaped canals in resin blocks were assigned to two groups (n = 20 for each group). Photographic method was used to record pre- and postinstrumentation images. After superimposition, centering and shaping ability were recorded at 9 different levels from the apex using the software Autocad 2013 (Autodesk Inc., San Rafael, USA). Results. Shaping procedures with ProTaper Next resulted in a lower amount of resin removed at each reference point level. In addition, the pattern of centering ability improved after the use of ProTaper Next in 8 of 9 measurement points. Conclusions. Within the limitations of this study, shaping procedures with ProTaper Next instruments demonstrated a lower amount of resin removed and a better centering ability than WaveOne Classic system. PMID:28054031

  12. Centering Ability of ProTaper Next and WaveOne Classic in J-Shape Simulated Root Canals.

    PubMed

    Troiano, Giuseppe; Dioguardi, Mario; Cocco, Armando; Giuliani, Michele; Fabiani, Cristiano; D'Alessandro, Alfonso; Ciavarella, Domenico; Lo Muzio, Lorenzo

    2016-01-01

    Introduction. The aim of this study was to evaluate and compare the shaping and centering ability of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) and WaveOne Classic systems (Dentsply Maillefer) in simulated root canals. Methods. Forty J-shaped canals in resin blocks were assigned to two groups (n = 20 for each group). Photographic method was used to record pre- and postinstrumentation images. After superimposition, centering and shaping ability were recorded at 9 different levels from the apex using the software Autocad 2013 (Autodesk Inc., San Rafael, USA). Results. Shaping procedures with ProTaper Next resulted in a lower amount of resin removed at each reference point level. In addition, the pattern of centering ability improved after the use of ProTaper Next in 8 of 9 measurement points. Conclusions. Within the limitations of this study, shaping procedures with ProTaper Next instruments demonstrated a lower amount of resin removed and a better centering ability than WaveOne Classic system.

  13. 3D Numerical Simulation of Turbulent Buoyant Flow and Heat Transport in a Curved Open Channel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-dimensional buoyancy-extended version of kappa-epsilon turbulence model was developed for simulating the turbulent flow and heat transport in a curved open channel. The density- induced buoyant force was included in the model, and the influence of temperature stratification on flow field was...

  14. Monte Carlo Simulations for the Purpose of Efficiency Curve Calibration for the Fastscan Whole Body Counter

    NASA Astrophysics Data System (ADS)

    Graham, Hannah Robyn

    In order to be able to qualify and quantify radiation exposure in terms of dose, a Fastscan whole body counter must be calibrated correctly. Current calibration methods do not take the full range of body types into consideration when creating efficiency curve calibrations. The goal of this work is the creation of a Monte Carlo (MCNP) model, that allows the simulation of efficiency curves for a diverse population of subjects. Models were created for both the Darlington and the Pickering Fastscan WBCs, and the simulations were benchmarked against experimental results with good agreement. The Pickering Fastscan was found to have agreement to within +/-9%, and the Darlington Fastscan had agreement to within +/-11%. Further simulations were conducted to investigate the effects of increased body fat on the detected activity, as well as locating the position of external contamination using front/back ratios of activity. Simulations were also conducted to create efficiency calibrations that had good agreement with the manufacturer's efficiency curves. The work completed in this thesis can be used to create efficiency calibration curves for unique body compositions in the future.

  15. Manual flying of curved precision approaches to landing with electromechanical instrumentation. A piloted simulation study

    NASA Technical Reports Server (NTRS)

    Knox, Charles E.

    1993-01-01

    A piloted simulation study was conducted to examine the requirements for using electromechanical flight instrumentation to provide situation information and flight guidance for manually controlled flight along curved precision approach paths to a landing. Six pilots were used as test subjects. The data from these tests indicated that flight director guidance is required for the manually controlled flight of a jet transport airplane on curved approach paths. Acceptable path tracking performance was attained with each of the three situation information algorithms tested. Approach paths with both multiple sequential turns and short final path segments were evaluated. Pilot comments indicated that all the approach paths tested could be used in normal airline operations.

  16. The X-ray Variability of NGC 4945: Characterizing the Power Spectrum through Light Curve Simulations

    SciTech Connect

    Mueller, M

    2003-12-17

    For light curves sampled on an uneven grid of observation times, the shape of the power density spectrum (PDS) includes severe distortion effects due to the window function, and simulations of light curves are indispensable to recover the true PDS. We present an improved method for comparing light curves generated from a PDS model to the measured data and apply it to a 50-day long RXTE observations of NGC 4945, a Seyfert 2 galaxy with well-determined mass from megamaser observations. The improvements over previously reported investigations include the adjustment of the PDS model normalization for each simulated light curve in order to directly investigate how well the chosen PDS shape describes the source data. We furthermore implement a robust goodness-of-fit measure that does not depend on the form of the variable used to describe the power in the periodogram. We conclude that a knee-type function (smoothly broken power law) describes the data better than a simple power law; the best-fit break frequency is {approx} 10{sup -6} Hz.

  17. Projectile shape influence on ballistic limit curves as determined by computational simulation

    SciTech Connect

    Hertel, E.S. Jr.; Chhabildas, L.C.

    1995-09-01

    A requirement for an effective debris shield is that it must protect a spacecraft from impacts by irregularly shaped particles. A series of numerical simulations has been performed using the multi-dimensional shock physics code CTH to numerically determine the ballistic limit curve for a Whipple bumper shield. Two different projectile shapes are considered for the numerical simulations, flat plates of varying diameters with a constant thickness and spheres of varying diameters. The critical diameter of ballistic limit was determined over a velocity range from 4 km/s to 15 km/s. We have found both experimentally and numerically that the particle shape has a significant effect on the debris cloud distribution, ballistic limit curve, and penetration capability.

  18. Dispersion curves from short-time molecular dynamics simulation. 1. Diatomic chain results

    SciTech Connect

    Noid, D.W.; Broocks, B.T.; Gray, S.K.; Marple, S.L.

    1988-06-16

    The multiple signal classification method (MUSIC) for frequency estimation is used to compute the frequency dispersion curves of a diatomic chain from the time-dependent structure factor. In this paper, the authors demonstrate that MUSIC can accurately determine the frequencies from very short time trajectories. MUSIC is also used to show how the frequencies can vary in time, i.e., along a trajectory. The method is ideally suited for analyzing molecular dynamics simulations of large systems.

  19. Comparative Study on Two Melting Simulation Methods: Melting Curve of Gold

    NASA Astrophysics Data System (ADS)

    Liu, Zhong-Li; Sun, Jun-Sheng; Li, Rui; Zhang, Xiu-Lu; Cai, Ling-Cang

    2016-05-01

    Melting simulation methods are of crucial importance to determining melting temperature of materials efficiently. A high-efficiency melting simulation method saves much simulation time and computational resources. To compare the efficiency of our newly developed shock melting (SM) method with that of the well-established two-phase (TP) method, we calculate the high-pressure melting curve of Au using the two methods based on the optimally selected interatomic potentials. Although we only use 640 atoms to determine the melting temperature of Au in the SM method, the resulting melting curve accords very well with the results from the TP method using much more atoms. Thus, this shows that a much smaller system size in SM method can still achieve a fully converged melting curve compared with the TP method, implying the robustness and efficiency of the SM method. Supported by the National Natural Science Foundation of China under Grant No. 41574076 and the NSAF of China under Grant No. U1230201/A06, and the Young Core Teacher Scheme of Henan Province under Grant No. 2014GGJS-108

  20. Scanning electron microscopic evaluation of the influence of manual and mechanical glide path on the surface of nickel-titanium rotary instruments in moderately curved root canals: An in-vivo study

    PubMed Central

    Patel, Dishant; Bashetty, Kusum; Srirekha, A.; Archana, S.; Savitha, B.; Vijay, R.

    2016-01-01

    Aim: The aim of this study was to evaluate the influence of manual versus mechanical glide path (GP) on the surface changes of two different nickel-titanium rotary instruments used during root canal therapy in a moderately curved root canal. Materials and Methods: Sixty systemically healthy controls were selected for the study. Controls were divided randomly into four groups: Group 1: Manual GP followed by RaCe rotary instruments, Group 2: Manual GP followed by HyFlex rotary instruments, Group 3: Mechanical GP followed by RaCe rotary instruments, Group 4: Mechanical GP followed by HyFlex rotary instruments. After access opening, GP was prepared and rotary instruments were used according to manufacturer's instructions. All instruments were evaluated for defects under standard error mean before their use and after a single use. The scorings for the files were given at apical and middle third. Statistical Analysis Used: Chi-squared test was used. Results: The results showed that there is no statistical difference between any of the groups. Irrespective of the GP and rotary files used, more defects were present in the apical third when compared to middle third of the rotary instrument. Conclusion: Within the limitations of this study, it can be concluded that there was no effect of manual or mechanical GP on surface defects of subsequent rotary file system used. PMID:27994317

  1. 2D PIC simulations of a curved supercritical shock: dynamics of the whistler precursor

    NASA Astrophysics Data System (ADS)

    Stienlet, Joël.; Savoini, Philippe; Lembege, Bertrand

    2010-05-01

    The whistler precursor emitted from the curved terrestrial shock front plays an important role in pre-decelerating and heating the incoming solar wind. Most previous works have mainly analyzed the features of the whistler precursor emission for a 1D planar shock where it is forced to propagate along the shock normal (Liewer and al, 1991) or to propagate obliquely with respect to a fixed shock normal direction in 2D planar shock simulation (Krauss-Varban et al., 1995). In the present case, the dynamics of the precursor is analyzed with the help of a 2D full particle simulation for a continuously curved shock within the angular range 90o ≥ ?Bn ≥ 45o where ?Bn is the angle between the shock normal and the upstream magnetostatic field. Both electrons and ions dynamics are described by a self consistent approach. Our results show that (i) the whistler precursor extends far from the shock front mainly along the magnetostatic field (projected on the simulation plane) and not along the shock normal; (ii) the width of these curved wave fronts (precursor) strongly decreases when moving far from the shock front; (iii) at the shock front, the precursor is emitted within an angular range much larger than that predicted by linear theory; (iv) the damping rate of the whistler precursor is analyzed for different directions of the shock normal. Wave particle energy transfer is analysed, and these results will be discussed and compared with previous 1D and 2D simulations of planar shocks; (v) the whistler precursor is not monochromatic, and interferences between modes are evidenced by beats and wave-packets in front of the shock. The impact of this effect on damping rate measurements will be discussed.

  2. Flow and transport simulation models for prediction of chlorine contact tank flow-through curves.

    PubMed

    Wang, Hong; Shao, Xuejun; Falconer, Roger A

    2003-01-01

    Turbulent flow, solute transport, and chemical and biological decay are some of the basic processes encountered in water treatment plants. This paper presents recent developments in the numerical simulation of turbulent flow and disinfection processes in disinfection contact tanks. Simulation runs have been conducted for various tank design alternatives and in different grid resolutions. The accuracy of simulated contact tank flow and the disinfection process depends largely on calculations of the hydrodynamic and solute transport characteristics in the tanks. A key factor of this is the accuracy of advection and shear stress term computations, which can be affected by the use of different hydrodynamic submodels and numerical schemes. The performance of a simulation model relies to a great extent on the right combination of such submodels and numerical schemes. In this study, a number of simulation models were tested against realistic tank configurations and measurements to evaluate the various combinations of turbulence models and difference schemes by analyzing predicted flow and solute transport patterns, as well as the corresponding flow-through curves. Models for disinfection tank simulations are recommended based on comparisons of simulation results with measurements. These models may also be applied to other water treatment processes such as wastewater treatment.

  3. Supernova Shock Breakout Light Curves and Spectra from CASTRO Multigroup Radiation Simulations

    NASA Astrophysics Data System (ADS)

    Lovegrove, Elizabeth; Woosley, S. E.

    2014-01-01

    We present preliminary results from a study of supernova shock breakout with the new multigroup radiation transport version of the CASTRO simulation code. Shock breakout occurs when the outgoing shockwave of a supernova explosion reaches the surface of the progenitor star and produces a bright flash. The breakout flash's spectral temperature, duration, and luminosity carry information about the progenitor star that may otherwise be very difficult to recover. To aid in detection and understanding of this phenomenon, we present integrated light curves and spectra of breakouts from a range of progenitors and explosions, including very low energy supernovae and pair-instability supernovae.

  4. Molecular dynamics simulations of the melting curve of NiAl alloy under pressure

    SciTech Connect

    Zhang, Wenjin; Peng, Yufeng; Liu, Zhongli

    2014-05-15

    The melting curve of B2-NiAl alloy under pressure has been investigated using molecular dynamics technique and the embedded atom method (EAM) potential. The melting temperatures were determined with two approaches, the one-phase and the two-phase methods. The first one simulates a homogeneous melting, while the second one involves a heterogeneous melting of materials. Both approaches reduce the superheating effectively and their results are close to each other at the applied pressures. By fitting the well-known Simon equation to our melting data, we yielded the melting curves for NiAl: 1783(1 + P/9.801){sup 0.298} (one-phase approach), 1850(1 + P/12.806){sup 0.357} (two-phase approach). The good agreement of the resulting equation of states and the zero-pressure melting point (calc., 1850 ± 25 K, exp., 1911 K) with experiment proved the correctness of these results. These melting data complemented the absence of experimental high-pressure melting of NiAl. To check the transferability of this EAM potential, we have also predicted the melting curves of pure nickel and pure aluminum. Results show the calculated melting point of Nickel agrees well with experiment at zero pressure, while the melting point of aluminum is slightly higher than experiment.

  5. Confocal laser scanning, scanning electron, and transmission electron microscopy investigation of Enterococcus faecalis biofilm degradation using passive and active sodium hypochlorite irrigation within a simulated root canal model.

    PubMed

    Mohmmed, Saifalarab A; Vianna, Morgana E; Penny, Matthew R; Hilton, Stephen T; Mordan, Nicola; Knowles, Jonathan C

    2017-02-28

    Root canal irrigation is an important adjunct to control microbial infection. The aim of this study was to investigate the effect of 2.5% (wt/vol) sodium hypochlorite (NaOCl) agitation on the removal, killing, and degradation of Enterococcus faecalis biofilm. A total of 45 root canal models were manufactured using 3D printing with each model comprising an 18 mm length simulated root canal of apical size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3 mm of the models for 10 days. A total of 60 s of 9 ml of 2.5% NaOCl irrigation using syringe and needle was performed, the irrigant was either left stagnant in the canal or agitated using manual (Gutta-percha), sonic, and ultrasonic methods for 30 s. Following irrigation, the residual biofilms were observed using confocal laser scanning, scanning electron, and transmission electron microscopy. The data were analyzed using one-way ANOVA with Dunnett post hoc tests at a level of significance p ≤ .05. Consequence of root canal irrigation indicate that the reduction in the amount of biofilm achieved with the active irrigation groups (manual, sonic, and ultrasonic) was significantly greater when compared with the passive and untreated groups (p < .05). Collectively, finding indicate that passive irrigation exhibited more residual biofilm on the model surface than irrigant agitated by manual or automated (sonic, ultrasonic) methods. Total biofilm degradation and nonviable cells were associated with the ultrasonic group.

  6. Prior-knowledge-based feedforward network simulation of true boiling point curve of crude oil.

    PubMed

    Chen, C W; Chen, D Z

    2001-11-01

    Theoretical results and practical experience indicate that feedforward networks can approximate a wide class of functional relationships very well. This property is exploited in modeling chemical processes. Given finite and noisy training data, it is important to encode the prior knowledge in neural networks to improve the fit precision and the prediction ability of the model. In this paper, as to the three-layer feedforward networks and the monotonic constraint, the unconstrained method, Joerding's penalty function method, the interpolation method, and the constrained optimization method are analyzed first. Then two novel methods, the exponential weight method and the adaptive method, are proposed. These methods are applied in simulating the true boiling point curve of a crude oil with the condition of increasing monotonicity. The simulation experimental results show that the network models trained by the novel methods are good at approximating the actual process. Finally, all these methods are discussed and compared with each other.

  7. 2D PIC simulations of a curved supercritical shock: dynamics of the whistler precursor

    NASA Astrophysics Data System (ADS)

    Stienlet, J.; Lembege, B.; Savoini, P.

    2009-12-01

    The whistler precursor emitted from the curved terrestrial shock front plays an important role in pre-decelerating and heating the incoming solar wind. Most previous works have mainly analyzed the features of the whistler precursor emission for a 1D planar shock where it is forced to propagate along the shock normal (Liewer and al, 1991) or to propagate obliquely with respect to a fixed shock normal direction in 2D planar shock simulation (Krauss-Varban et al., 1995). In the present case, the dynamics of the precursor is analyzed for a full curved shock with the help of a 2D full particle simulation where full curvature effects and both electrons and ions dynamics are described by a self consistent approach. Curvature effects continously cover all shock normal directions within the angular range 90° ≤ θBn ≤ 45° where θBn is the angle between the shock normal and the upstream magnetostatic field. This approach allows a free accessibility of the whistler precursor to a large angular range without any constraint. Preliminary results show that : (i) the whistler precursor strongly extends far from the shock front mainly along the magnetostatic field (projected on the simulation plane) but this extension is progressively reduced outside this privileged direction; (ii) wave fronts of the whistler precursor have a curvature similar to that of the main curved shock front but the width of these curved wave fronts strongly decreases when moving far from the shock front; (iii) near the shock front, the precursor is emitted within an angular range much larger than that predicted by linear theory; (iv) the critical angle of occurrence of the precursor fits with the theoretical value expected from Krasnoselskikh et al. (2002) model but this angle is not associated to a transition between stationary and non-stationary shocks in contrast with a statement announced by this theoretical model; and (v) the damping rate of the whistler precursor is analyzed for different

  8. Toward computer simulation of high-LET in vitro survival curves

    NASA Astrophysics Data System (ADS)

    Heuskin, A.-C.; Michiels, C.; Lucas, S.

    2013-09-01

    We developed a Monte Carlo based computer program called MCSC (Monte Carlo Survival Curve) able to predict the survival fraction of cells irradiated in vitro with a broad beam of high linear energy transfer particles. Three types of cell responses are studied: the usual high dose response, the bystander effect and the low-dose hypersensitivity (HRS). The program models the broad beam irradiation and double strand break distribution following Poisson statistics. The progression of cells through the cell cycle is taken into account while the repair takes place. Input parameters are experimentally determined for A549 lung carcinoma cells irradiated with 10 and 20 keV µm-1 protons, 115 keV µm-1 alpha particles and for EAhy926 endothelial cells exposed to 115 keV µm-1 alpha particles. Results of simulations are presented and compared with experimental survival curves obtained for A549 and EAhy296 cells. Results are in good agreement with experimental data for both cell lines and all irradiation protocols. The benefits of MCSC are several: the gain of time that would have been spent performing time-consuming clonogenic assays, the capacity to estimate survival fraction of cell lines not forming colonies and possibly the evaluation of radiosensitivity parameters of given individuals.

  9. A fixed-base simulation study of two STOL aircraft flying curved, descending instrument approach paths

    NASA Technical Reports Server (NTRS)

    Benner, M. S.; Sawyer, R. H.; Mclaughlin, M. D.

    1973-01-01

    A real-time, fixed-base simulation study has been conducted to determine the curved, descending approach paths (within passenger-comfort limits) that would be acceptable to pilots, the flight-director-system logic requirements for curved-flight-path guidance, and the paths which can be flown within proposed microwave landing system (MLS) coverage angles. Two STOL aircraft configurations were used in the study. Generally, no differences in the results between the two STOL configurations were found. The investigation showed that paths with a 1828.8 meter turn radius and a 1828.8 meter final-approach distance were acceptable without winds and with winds up to at least 15 knots for airspeeds from 75 to 100 knots. The altitude at roll-out from the final turn determined which final-approach distances were acceptable. Pilots preferred to have an initial straight leg of about 1 n. mi. after MLS guidance acquisition before turn intercept. The size of the azimuth coverage angle necessary to meet passenger and pilot criteria depends on the size of the turn angle: plus or minus 60 deg was adequate to cover all paths execpt ones with a 180 deg turn.

  10. Effects of the offset term in experimental simulation on afterglow decay curve.

    PubMed

    Tsai, Chi-Yang; Lin, Jeng-Wen; Huang, Yih-Ping; Huang, Yung-Chieh

    2014-01-01

    This study examines the effect of the offset term in a multiple single exponential equation that fits into experimental afterglow decay curve data for material applications. For afterglow materials applied and attached to structures, the inclusion of this offset term may reduce the values of the calculated decay times, τ i , and enlarge the time invariant constants, A i , in the associated equation compared to theoretically perfect test conditions. Using a set of experimental data obtained from a lab under dim light, adjustments can be made to calculate the required parameters for an equation without the offset term. This study uses mathematical simulations and lab tests to support our thesis and crosslink test results generated from different ambient light conditions. This paper defines the offset ratio as the ratio of the offset value, I 0, versus the initial light intensity in an equation. This ratio can be used to evaluate possible effects on the calculated parameters of an equation in an associated numerical simulation. The most reliable parameters will have consistent results from the use of multiple single exponential equations, with and without the offset term, in simulations to obtain them in an equation to model a set of data.

  11. Rupture Dynamics Simulation for Non-Planar fault by a Curved Grid Finite Difference Method

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Zhu, G.; Chen, X.

    2011-12-01

    We first implement the non-staggered finite difference method to solve the dynamic rupture problem, with split-node, for non-planar fault. Split-node method for dynamic simulation has been used widely, because of that it's more precise to represent the fault plane than other methods, for example, thick fault, stress glut and so on. The finite difference method is also a popular numeric method to solve kinematic and dynamic problem in seismology. However, previous works focus most of theirs eyes on the staggered-grid method, because of its simplicity and computational efficiency. However this method has its own disadvantage comparing to non-staggered finite difference method at some fact for example describing the boundary condition, especially the irregular boundary, or non-planar fault. Zhang and Chen (2006) proposed the MacCormack high order non-staggered finite difference method based on curved grids to precisely solve irregular boundary problem. Based upon on this non-staggered grid method, we make success of simulating the spontaneous rupture problem. The fault plane is a kind of boundary condition, which could be irregular of course. So it's convinced that we could simulate rupture process in the case of any kind of bending fault plane. We will prove this method is valid in the case of Cartesian coordinate first. In the case of bending fault, the curvilinear grids will be used.

  12. Numerical simulation of flow and aquaculture organic waste dispersion in a curved channel

    NASA Astrophysics Data System (ADS)

    Ali, Alfatih; Thiem, Øyvind; Berntsen, Jarle

    2013-10-01

    The dispersion and deposition of particulate organic matter from a fish cage located in an idealized curved channel with a 90° bend are studied for different horizontal grid resolutions. The model system consists of a three-dimensional, random-walk particle tracking model coupled to a terrain-following ocean model. The particle tracking model is a Lagrangian particle tracking simulator which uses the local flow field, simulated by the ocean model, for advection of the particles and random walk to simulate the turbulent diffusion. The sinking of particles is modeled by imposing an individual particle settling velocity. As the homogeneous water flows through the bend in the channel, the results show that a cross-channel secondary circulation is developed. The motion of this flow is similar to a helical motion where the water in the upper layers moves towards the outer bank and towards the inner bank in the lower layers. The intensity of the secondary circulation will depend on the viscosity scheme and increases as the horizontal grid resolution decreases which significantly affects the distribution of the particles on the seabed. The presence of the secondary circulation leads to that most of the particles that settle, settle close to the inner bank of the channel.

  13. Spectral optimization simulation of white light based on the photopic eye-sensitivity curve

    NASA Astrophysics Data System (ADS)

    Dai, Qi; Hao, Luoxi; Lin, Yi; Cui, Zhe

    2016-02-01

    Spectral optimization simulation of white light is studied to boost maximum attainable luminous efficacy of radiation at high color-rendering index (CRI) and various color temperatures. The photopic eye-sensitivity curve V(λ) is utilized as the dominant portion of white light spectra. Emission spectra of a blue InGaN light-emitting diode (LED) and a red AlInGaP LED are added to the spectrum of V(λ) to match white color coordinates. It is demonstrated that at the condition of color temperature from 2500 K to 6500 K and CRI above 90, such white sources can achieve spectral efficacy of 330-390 lm/W, which is higher than the previously reported theoretical maximum values. We show that this eye-sensitivity-based approach also has advantages on component energy conversion efficiency compared with previously reported optimization solutions.

  14. Spectral optimization simulation of white light based on the photopic eye-sensitivity curve

    SciTech Connect

    Dai, Qi; Hao, Luoxi; Lin, Yi; Cui, Zhe

    2016-02-07

    Spectral optimization simulation of white light is studied to boost maximum attainable luminous efficacy of radiation at high color-rendering index (CRI) and various color temperatures. The photopic eye-sensitivity curve V(λ) is utilized as the dominant portion of white light spectra. Emission spectra of a blue InGaN light-emitting diode (LED) and a red AlInGaP LED are added to the spectrum of V(λ) to match white color coordinates. It is demonstrated that at the condition of color temperature from 2500 K to 6500 K and CRI above 90, such white sources can achieve spectral efficacy of 330–390 lm/W, which is higher than the previously reported theoretical maximum values. We show that this eye-sensitivity-based approach also has advantages on component energy conversion efficiency compared with previously reported optimization solutions.

  15. The Water Retention Curves in THF Hydrate-Bearing Sediments - Experimental Measurement and Pore Scale Simulation

    NASA Astrophysics Data System (ADS)

    Mahabadi, N.; Zheng, X.; Dai, S.; Seol, Y.; Zapata, C.; Yun, T.; Jang, J.

    2015-12-01

    The water retention curve (WRC) of hydrate-bearing sediments is critically important to understand the behaviour of hydrate dissociation for gas production. Most gas hydrates in marine environment have been formed from an aqueous phase (gas-dissolved water). However, the gas hydrate formation from an aqueous phase in a laboratory requires long period due to low gas solubility in water and is also associated with many experimental difficulties such as hydrate dissolution, difficult hydrate saturation control, and dynamic hydrate dissolution and formation. In this study, tetrahydrofuran (THF) is chosen to form THF hydrate because the formation process is faster than gas hydrate formation and hydrate saturation is easy to control. THF hydrate is formed at water-excess condition. Therefore, there is only water in the pore space after a target THF hydrate saturation is obtained. The pore habit of THF hydrate is investigated by visual observation in a transparent micromodel and X-ray computed tomography images; and the water retention curves are obtained under different THF hydrate saturation conditions. Targeted THF hydrate saturations are Sh=0, 0.2, 0.4, 0.6 and 0.8. Results shown that at a given water saturation the capillary pressure increases as THF hydrate saturation increases. And the gas entry pressure increases with increasing hydrate saturation. The WRC obtained by experiments is also compared with the results of a pore-network model simulation and Lattice Boltzmann Method. The fitting parameters of van Genuchten equation for different hydrate saturation conditions are suggested for the use as input parameters of reservoir simulators.

  16. Light Curves from an MHD Simulation of a Black Hole Accretion Disk

    NASA Astrophysics Data System (ADS)

    Schnittman, Jeremy D.; Krolik, Julian H.; Hawley, John F.

    2006-11-01

    We use a relativistic ray-tracing code to calculate the light curves observed from a global, general relativistic, magnetohydrodynamic simulation of an accretion flow onto a Schwarzschild black hole. We apply three basic emission models to sample different properties of the time-dependent accretion disk. With one of these models, which assumes thermal blackbody emission and free-free absorption, we can predict qualitative features of the high-frequency power spectrum from stellar-mass black holes in the ``thermal dominant'' state. The simulated power spectrum is characterized by a power law of index Γ~3 and total rms fractional variance of <~2% above 10 Hz. For each emission model, we find that the variability amplitude should increase with increasing inclination angle. On the basis of a newly developed formalism for quantifying the significance of quasi-periodic oscillations (QPOs) in simulation data, we find that these simulations are able to identify any such features with (rms/mean) amplitudes >~1% near the orbital frequency at the innermost stable orbit. Initial results indicate the existence of transient QPO peaks with frequency ratios of nearly 2:3 at a 99.9% confidence limit, but they are not generic features, because at any given time they are seen only from certain observer directions. In addition, we present detailed analysis of the azimuthal structure of the accretion disk and the evolution of density perturbations in the inner disk. These ``hot-spot'' structures appear to be roughly self-similar over a range of disk radii, with a single characteristic size δφ=25deg and δr/r=0.3, and typical lifetimes Tl~0.3Torb.

  17. Rotation curve fitting and its fatal attraction to cores in realistically simulated galaxy observations

    NASA Astrophysics Data System (ADS)

    Pineda, Juan C. B.; Hayward, Christopher C.; Springel, Volker; Mendes de Oliveira, Claudia

    2017-04-01

    We study the role of systematic effects in observational studies of the cusp-core problem under the minimum disc approximation using a suite of high-resolution (25-pc softening length) hydrodynamical simulations of dwarf galaxies. We mimic realistic kinematic observations and fit the mock rotation curves with two analytic models commonly used to differentiate cores from cusps in the dark matter distribution. We find that the cored pseudo-isothermal sphere (ISO) model is strongly favoured by the reduced χ ^2_ν of the fits in spite of the fact that our simulations contain cuspy Navarro-Frenk-White profiles (NFW). We show that even idealized measurements of the gas circular motions can lead to the incorrect answer if velocity underestimates induced by pressure support, with a typical size of order ∼5 km s-1 in the central kiloparsec, are neglected. Increasing the spatial resolution of the mock observations leads to more misleading results because the inner region, where the effect of pressure support is most significant, is better sampled. Fits to observations with a spatial resolution of 100 pc (2 arcsec at 10 Mpc) favour the ISO model in 78-90 per cent of the cases, while at 800-pc resolution, 41-77 per cent of the galaxies indicate the fictitious presence of a dark matter core. The coefficients of our best-fitting models agree well with those reported in observational studies; therefore, we conclude that NFW haloes cannot be ruled out reliably from this type of analysis.

  18. High-order numerical simulations of pulsatile flow in a curved artery model

    NASA Astrophysics Data System (ADS)

    Cox, Christopher; Liang, Chunlei; Plesniak, Michael W.

    2016-11-01

    Cardiovascular flows are pulsatile, incompressible and occur in complex geometries with compliant walls. Together, these factors can produce an environment that can affect the progression of cardiovascular disease by altering wall shear stresses. Unstructured high-order CFD methods are well suited for capturing unsteady vortex-dominated viscous flows, and these methods provide high accuracy for similar cost as low-order methods. We use an in-house three-dimensional flux reconstruction Navier-Stokes solver to simulate secondary flows and vortical structures within a rigid 180-degree curved artery model under pulsatile flow of a Newtonian blood-analog fluid. Our simulations use a physiological flowrate waveform taken from the carotid artery. We are particularly interested in the dynamics during the deceleration phase of the waveform, where we observe the deformed-Dean, Dean, Lyne and Wall vortices. Our numerical results reveal the complex nature of these vortices both in space and time and their effect on overall wall shear stress. Numerical results agree with and complement experimental results obtained in our laboratory using particle image velocimetry. Supported by the GW Center for Biomimetics and Bioinspired Engineering.

  19. Analog-model simulations for secondary canal controls and forward pumping water-management schemes in southeast Florida

    USGS Publications Warehouse

    Cordes, E.H.; Gardner, Richard Alfred

    1976-01-01

    The analog model of the Biscayne aquifer of southeast Florida was used to approximate the effects of two proposed water-management schemes. One involved adding a secondary control structure in a major canal which is controlled near the coast. In the model the controls were operated in accordance with canal water level both above and below the secondary control. Although the model could not differentiate between control openings of 1 foot or 5 feet, it showed that the secondary control is a viable method of conserving ground water. The second scheme involved pumping ground water ('forward pumping') from the Biscayne aquifer in inland areas during the dry season to: (1) augment canal flows toward the coast to sustain ground-water levels there, and (2) generate additional ground-water storage space for recharge in the wet season. Several sites on the model were programmed for forward pumping wells and the storage change was noted as a percentage of the ground-water withdrawal. (Woodard-USGS)

  20. Impact of truncated area under the curve on failed bioequivalence studies: a computer simulation analysis.

    PubMed

    Mahmood, Iftekhar

    2004-01-01

    The common measures used in a bioequivalence study are area under the curve (AUC) and the maximum plasma concentration. Estimation of AUC requires frequent blood samples. For long half-life drugs, sampling for long periods of time may become cumbersome. To resolve this issue some investigators have suggested the use of truncated AUC in bioequivalence studies for long half-life drugs. The suggested length of time for the truncated AUC is 72 hours. Many studies have been conducted to show that truncated AUC till 72 hours is a suitable approach. However, the suitability of truncated AUC for failed bioequivalence study has not been demonstrated. This report of simulated plasma concentration versus time data evaluates the suitability of truncated AUC for failed bioequivalence study of two hypothetical drugs. The results of the study indicate that the truncated approach for the estimation of the AUC for long half-life drugs in bioequivalence studies may be useful but it also increases the probability of accepting drugs as being bioequivalent when they are not.

  1. 3. ELEVATION. FROM SOUTH WITH CANAL PRISM. Canal Road ...

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

    3. ELEVATION. FROM SOUTH WITH CANAL PRISM. - Canal Road Bridge, Canal Road spanning Delaware Canal Diversion, Locks 22 & 23 in Delaware Canal State Park in Williams Township, Raubsville, Northampton County, PA

  2. Diagnosing Hydrologic Flow Paths in Forest and Pasture Land Uses within the Panama Canal Watershed Using Simulated Rainfall and Electrical Resistivity Tomography

    NASA Astrophysics Data System (ADS)

    Ogden, F. L.; Mojica, A.; Kempema, E. W.; Briceno, J. C.; Regina, J. A.

    2014-12-01

    Hydrological processes in the humid tropics are poorly understood and an important topic when it comes to water management in the seasonal tropics. The Smithsonian Tropical Research Institute, Panama Canal Watershed Experiment, Agua Salud Project, seeks to understand these processes and quantify the long-term effects of different land cover and use across the Panama Canal Watershed. In this study we used an ARS-type rainfall simulator to apply rainfall rates up to 200 mm per hour over a 2m by 6m area on deep saprolitic soils in forest and pasture land covers. A salinity contrast added to the applied rainwater allowed observation of bulk flow paths and velocities in the subsurface. The observed effects of land cover and land use on hydrological response were striking. In the forest site, we were unable to produce surface runoff even after the application of 600 mm of rainfall in three hours, and observed flow in soils down to approximately 2 m depth, and no downslope macropore flow. In the pasture site, surface runoff was produced, and we measured the permeability of the area with applied rainfall. Observed flow paths were much shallower, less than 1 m depth, with significant macropore flow observed at downslope positions. We hypothesize that land use and land cover have significant impacts on flow paths as they affect creation, connectivity, and function of biologically created macropores in the soil.

  3. Photometric Identification of Population III Core-Collapse Supernovae: Multicolor Light Curve Simulations

    NASA Astrophysics Data System (ADS)

    Tolstov, Alexey; Nomoto, Ken'ichi; Tominaga, Nozomu; Ishigaki, Miho N.; Blinnikov, Sergey; Suzuki, Tomoharu

    We study the multicolor light curves for a number of metal-free core-collapse supernova (SN) models (25-100 ȯ ) to determine the indicators for the detection and identification of first generation SNe. We use mixing-fallback supernova explosion models that explain the observed abundance patterns of metal-poor stars. Numerical calculations of the multicolor light curves are performed using the multigroup radiation hydrodynamic code STELLA. The calculated light curves of metal-free SNe are compared with solar-metallicity models and observed SNe. We conclude that the multicolor light curves could be used to identify first-generation SNe in current (Subaru/HSC) and future transient surveys (LSST, James Webb Space Telescope). They are also suitable for identifying low-metallicity SNe in the nearby universe (PTF, Pan-STARRS, Gaia).

  4. Accretion disc time lag distributions: applying CREAM to simulated AGN light curves

    NASA Astrophysics Data System (ADS)

    Starkey, D. A.; Horne, Keith; Villforth, C.

    2016-02-01

    Active galactic nuclei (AGN) vary in their brightness across all wavelengths. Moreover, longer wavelength ultraviolet-optical continuum light curves appear to be delayed with respect to shorter wavelength light curves. A simple way to model these delays is by assuming thermal reprocessing of a variable point source (a lamp post) by a blackbody accretion disc. We introduce a new method, CREAM (Continuum REprocessed AGN Markov Chain Monte Carlo), that models continuum variations using this lamp post model. The disc light curves lag the lamp post emission with a time delay distribution sensitive to the disc temperature-radius profile and inclination. We test CREAM's ability to recover both inclination and product of black hole mass and accretion rate {Mdot{M}}, and show that the code is also able to infer the shape of the driving light curve. CREAM is applied to synthetic light curves expected from 1000 s exposures of a 17th magnitude AGN with a 2-m telescope in Sloan g and i bands with Signal-to-Noise Ratio (SNR) of 500-900 depending on the filter and lunar phase. We also test CREAM on poorer quality g and i light curves with SNR = 100. We find in the high-SNR case that CREAM can recover the accretion disc inclination to within an uncertainty of 5° and an {Mdot{M}} to within 0.04 dex.

  5. 21. 1934 aerial of Tempe Canal, Sections 19 and 30 ...

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

    21. 1934 aerial of Tempe Canal, Sections 19 and 30 (T1N R5E) and Sections 24 and 25 (T1N R4E) (top of page is north). The main canal enters the picture at upper right and curves out of picture at lower right. The Hayden Branch (thin dark line) runs from top of picture to the southwest, then curves to the west. The Western Branch enters picture running parallel to main canal, then angles off to southwest. Photographer: Unknown, 1934. Source: SRP Cartographic Drafting - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  6. Simulation of ultrasonic inspection of curved composites using a hybrid semi-analytical/numerical code

    NASA Astrophysics Data System (ADS)

    Reverdy, Frédéric; Mahaut, Steve; Dominguez, Nicolas; Dubois, Philippe

    2015-03-01

    Carbon Fiber reinforced composites are increasingly used in structural parts in the aeronautics industry, as they allow to reduce the weight of aircrafts while maintaining high mechanical performances. However, such structures can be complicated to inspect due to their complex geometries and complex composite properties, leading to highly heterogeneous and anisotropic materials. Different potential damages and manufacturing flaws related to these parts are to be detected: porosities, ply waviness, delaminations after impact. Ultrasonic inspection, which is commonly used to test the full volume of composite panels, thus has to cope with both complex wave propagation (within anisotropic parts whose crystallographic orientation varies according to the layers structure) and flaw interaction (local distortion of plies such as ply waviness, small pores, structural noise due to periodicity patterns…). Developing NDT procedures for those parts therefore requires simulation tools to help for understanding those phenomena, and to optimize probes and techniques. Within the CIVA multi-techniques platform, CEA-LIST has developed semi-analytical tools for ultrasonic techniques, which have the advantages of high computational efficiency (fast calculations), but with limited range of application due to some hypothesis (for instance, homogenization approaches which don't allow to take account of structural noise). On the other hand, numerical methods such as finite element (FEM) or finite difference in time domain (FDTD) are more suitable to compute ultrasonic wave propagation and defect scattering in complex materials such as composite but require more computational efforts. Hybrid methods couple semi-analytical solutions and numerical computations in limited spatial domains to handle complex cases with high computation performances. In CIVA we have integrated a hybrid model that combines the semi-analytical methods developed at CEA to FDTD codes developed at Airbus Group

  7. Stochastic simulation of soil particle-size curves in heterogeneous aquifer systems through a Bayes space approach

    NASA Astrophysics Data System (ADS)

    Menafoglio, A.; Guadagnini, A.; Secchi, P.

    2016-08-01

    We address the problem of stochastic simulation of soil particle-size curves (PSCs) in heterogeneous aquifer systems. Unlike traditional approaches that focus solely on a few selected features of PSCs (e.g., selected quantiles), our approach considers the entire particle-size curves and can optionally include conditioning on available data. We rely on our prior work to model PSCs as cumulative distribution functions and interpret their density functions as functional compositions. We thus approximate the latter through an expansion over an appropriate basis of functions. This enables us to (a) effectively deal with the data dimensionality and constraints and (b) to develop a simulation method for PSCs based upon a suitable and well defined projection procedure. The new theoretical framework allows representing and reproducing the complete information content embedded in PSC data. As a first field application, we demonstrate the quality of unconditional and conditional simulations obtained with our methodology by considering a set of particle-size curves collected within a shallow alluvial aquifer in the Neckar river valley, Germany.

  8. Evolution of the SCS curve number method and its applications to continuous runoff simulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Natural Resources Conservation Service (NRCS) [previously Soil Conservation Service (SCS)] developed the SCS runoff curve-number (CN) method for estimating direct runoff from storm rainfall. The NRCS uses the CN method for designing structures and for evaluating their effectiveness. Structural...

  9. A Laboratory Simulation of Urban Runoff and the Potential for Hydrograph Prediction with Curve Numbers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Urban drainages are mosaics of pervious and impervious surfaces, and prediction of runoff hydrology with a lumped modeling approach using the NRCS curve number may be appropriate. However, the prognostic capability of such a lumped approach is complicated by routing and connectivity amongst infiltra...

  10. COMPARING THE LIGHT CURVES OF SIMULATED TYPE Ia SUPERNOVAE WITH OBSERVATIONS USING DATA-DRIVEN MODELS

    SciTech Connect

    Diemer, Benedikt; Kessler, Richard; Graziani, Carlo; Jordan, George C. IV; Lamb, Donald Q.; Long, Min; Van Rossum, Daniel R.

    2013-08-20

    We propose a robust, quantitative method to compare the synthetic light curves of a Type Ia supernova (SN Ia) explosion model with a large set of observed SNe Ia, and derive a figure of merit for the explosion model's agreement with observations. The synthetic light curves are fit with the data-driven model SALT2 which returns values for stretch, color, and magnitude at peak brightness, as well as a goodness-of-fit parameter. Each fit is performed multiple times with different choices of filter bands and epoch range in order to quantify the systematic uncertainty on the fitted parameters. We use a parametric population model for the distribution of observed SN Ia parameters from large surveys, and extend it to represent red, dim, and bright outliers found in a low-redshift SN Ia data set. We discuss the potential uncertainties of this population model and find it to be reliable given the current uncertainties on cosmological parameters. Using our population model, we assign each set of fitted parameters a likelihood of being observed in nature, and a figure of merit based on this likelihood. We define a second figure of merit based on the quality of the light curve fit, and combine the two measures into an overall figure of merit for each explosion model. We compute figures of merit for a variety of one-, two-, and three-dimensional explosion models and show that our evaluation method allows meaningful inferences across a wide range of light curve quality and fitted parameters.

  11. An evidence-based laparoscopic simulation curriculum shortens the clinical learning curve and reduces surgical adverse events

    PubMed Central

    De Win, Gunter; Van Bruwaene, Siska; Kulkarni, Jyotsna; Van Calster, Ben; Aggarwal, Rajesh; Allen, Christopher; Lissens, Ann; De Ridder, Dirk; Miserez, Marc

    2016-01-01

    Background Surgical simulation is becoming increasingly important in surgical education. However, the method of simulation to be incorporated into a surgical curriculum is unclear. We compared the effectiveness of a proficiency-based preclinical simulation training in laparoscopy with conventional surgical training and conventional surgical training interspersed with standard simulation sessions. Materials and methods In this prospective single-blinded trial, 30 final-year medical students were randomized into three groups, which differed in the way they were exposed to laparoscopic simulation training. The control group received only clinical training during residency, whereas the interval group received clinical training in combination with simulation training. The Center for Surgical Technologies Preclinical Training Program (CST PTP) group received a proficiency-based preclinical simulation course during the final year of medical school but was not exposed to any extra simulation training during surgical residency. After 6 months of surgical residency, the influence on the learning curve while performing five consecutive human laparoscopic cholecystectomies was evaluated with motion tracking, time, Global Operative Assessment of Laparoscopic Skills, and number of adverse events (perforation of gall bladder, bleeding, and damage to liver tissue). Results The odds of adverse events were 4.5 (95% confidence interval 1.3–15.3) and 3.9 (95% confidence interval 1.5–9.7) times lower for the CST PTP group compared with the control and interval groups. For raw time, corrected time, movements, path length, and Global Operative Assessment of Laparoscopic Skills, the CST PTP trainees nearly always started at a better level and were never outperformed by the other trainees. Conclusion Proficiency-based preclinical training has a positive impact on the learning curve of a laparoscopic cholecystectomy and diminishes adverse events. PMID:27512343

  12. Flow Curve Determination at Large Plastic Strain Levels to Accurately Constitutive Equations of AHSS in Forming Simulation

    NASA Astrophysics Data System (ADS)

    Lemoine, X.; Sriram, S.; Kergen, R.

    2011-05-01

    ArcelorMittal continuously develops new steel grades (AHSS) with high performance for the automotive industry to improve the weight reduction and the passive safety. The wide market introduction of AHSS raises a new challenge for manufacturers in terms of material models in the prediction of forming—especially formability and springback. The relatively low uniform elongation, the high UTS and the low forming limit curve of these AHSS may cause difficulties in forming simulations. One of these difficulties is the consequence of the relatively low uniform elongation on the parameters identification of isotropic hardening model. Different experimental tests allow to reach large plastic strain levels (hydraulic bulge test, stack compression test, shear test…). After a description on how to determine the flow curve in these experimental tests, a comparison of the different flow curves is made for different steel grades. The ArcelorMittal identification protocol for hardening models is only based on stress-strain curves determined in uniaxial tension. Experimental tests where large plastic strain levels are reached are used to validate our identification protocol and to recommend some hardening models. Finally, the influence of isotropic hardening models and yield loci in forming prediction for AHSS steels will be presented.

  13. A new approach to canal surface with parallel transport frame

    NASA Astrophysics Data System (ADS)

    Kiṣi, Ilim; Öztürk, Günay

    In the present study, we attend to the canal surfaces with the spine curve γ according to the parallel transport frame in Euclidean 4-space 𝔼4. We give an example of these surfaces and obtain some results about curvature conditions in 𝔼4. Moreover, the visualizations of projections of canal surfaces are presented. Lastly, we give the necessary and sufficient conditions for canal surfaces to become weak superconformal.

  14. New approaches to the simulation of heat-capacity curves and phase diagrams of pseudobinary phospholipid mixtures.

    PubMed Central

    Johann, C; Garidel, P; Mennicke, L; Blume, A

    1996-01-01

    A simulation program using least-squares minimization was developed to calculate and fit heat capacity (cp) curves to experimental thermograms of dilute aqueous dispersions of phospholipid mixtures determined by high-sensitivity differential scanning calorimetry. We analyzed cp curves and phase diagrams of the pseudobinary aqueous lipid systems 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol/ 1,2-dipalmitoyl-sn-glycero-3phosphatidylcholine (DMPG/DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphatidic acid/1, 2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DMPA/DPPC) at pH 7. The simulation of the cp curves is based on regular solution theory using two nonideality parameters rho g and rho l for symmetric nonideal mixing in the gel and the liquid-crystalline phases. The broadening of the cp curves owing to limited cooperativity is incorporated into the simulation by convolution of the cp curves calculated for infinite cooperativity with a broadening function derived from a simple two-state transition model with the cooperative unit size n = delta HVH/delta Hcal as an adjustable parameter. The nonideality parameters and the cooperative unit size turn out to be functions of composition. In a second step, phase diagrams were calculated and fitted to the experimental data by use of regular solution theory with four different model assumptions. The best fits were obtained with a four-parameter model based on nonsymmetric, nonideal mixing in both phases. The simulations of the phase diagrams show that the absolute values of the nonideality parameters can be changed in a certain range without large effects on the shape of the phase diagram as long as the difference of the nonideality parameters for rho g for the gel and rho l for the liquid-crystalline phase remains constant. The miscibility in DMPG/DPPC and DMPA/DPPC mixtures differs remarkably because, for DMPG/DPPC, delta rho = rho l -rho g is negative, whereas for DMPA/DPPC this difference is positive. For DMPA/DPPC, this

  15. Application of software for automated canal management (SacMan) to the WM lateral canal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulation studies have demonstrated that automatic control of canals is more effective when feedforward scheduling, or routing of know demand changes, is combined with centralized, automatic, distant, downstream-water-level control. In practice, few canals use this approach. To help further develop...

  16. Atrioventricular Canal Defect

    MedlinePlus

    ... al. Clinical manifestations, pathophysiology, and diagnosis of atrioventricular (AV) canal defects. http://www.uptodate.com/home. Accessed ... CE, et al. Management and outcome of atrioventricular (AV) canal defects. http://www.uptodate.com/home. Accessed ...

  17. 25. Photocopy of photograph (original print at Gage Canal Company ...

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

    25. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, March 1954. VIEW OF THE GAGE IRRIGATION CANAL, CONCRETE 'COVERING COMPLETED & BACKFILLED TO WATERMAN AVENUE...CURVING TOWARD NO. 1 TUNNEL' - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  18. MCRaT Simulations of Long Gamma Ray Burst Spectra and Light Curves

    NASA Astrophysics Data System (ADS)

    Parsotan, T.; Lazzati, D.

    2016-10-01

    We present the results of the Monte Carlo Radiation Transfer, MCRaT, simulations of long gamma ray bursts from a variety of stellar progenitors and jet properties, including variable engines. We also compare the resulting spectra to observed data.

  19. Simulation of tissue activity curves of 64Cu-ATSM for sub-target volume delineation in radiotherapy

    NASA Astrophysics Data System (ADS)

    Dalah, E.; Bradley, D.; Nisbet, A.

    2010-02-01

    There is much interest in positron emission tomography (PET) for measurements of regional tracer concentration in hypoxic tumour-bearing tissue, focusing on the need for accurate radiotherapy treatment planning. Generally, relevant data are taken over multiple time frames in the form of tissue activity curves (TACs), thus providing an indication of vasculature structure and geometry. This is a potential key in providing information on cellular perfusion and limited diffusion. A number of theoretical studies have attempted to describe tracer uptake in tissue cells in an effort to understand such complicated behaviour of cellular uptake and the mechanism of washout. More recently, a novel computerized reaction diffusion equation method was developed by Kelly and Brady (2006 A model to simulate tumour oxygenation and dynamic [18F]-FMISO PET data Phys. Med. Biol. 51 5859-73), where they managed to simulate the realistic dynamic TACs of 18F-FMISO. The model was developed over a multi-step process. Here we present a refinement to the work of Kelly and Brady, such that the model allows simulation of a realistic tissue activity curve (TAC) of any hypoxia selective PET tracer, in a single step process. In this work we show particular interest in simulating the TAC of perhaps the most promising hypoxia selective tracer, 64Cu-ATSM. In addition, we demonstrate its potential role in tumour sub-volume delineation for radiotherapy treatment planning. Simulation results have demonstrated the significant high contrast of imaging using ATSM, with a tumour to blood ratio ranging from 2.24 to 4.1.

  20. Simulations of peristaltic slip-flow of hydromagnetic bio-fluid in a curved channel

    NASA Astrophysics Data System (ADS)

    Ali, N.; Javid, K.; Sajid, M.

    2016-02-01

    The influence of slip and magnetic field on transport characteristics of a bio-fluid are analyzed in a curved channel. The problem is modeled in curvilinear coordinate system under the assumption that the wavelength of the peristaltic wave is larger in magnitude compared to the width of the channel. The resulting nonlinear boundary value problem (BVP) is solved using an implicit finite difference technique (FDT). The flow velocity, pressure rise per wavelength and stream function are illustrated through graphs for various values of rheological and geometrical parameters of the problem. The study reveals that a thin boundary layer exists at the channel wall for strong magnetic field. Moreover, small values of Weissenberg number counteract the curvature and make the velocity profile symmetric. It is also observed that pressure rise per wavelength in pumping region increases (decreases) by increasing magnetic field, Weissenberg number and curvature of the channel (slip parameter).

  1. Large-eddy simulation of curved-geometry flows using contravariant components of velocity

    NASA Astrophysics Data System (ADS)

    Yuan, Weixing; Xu, Hongyi; Khalid, Mahmood

    2011-01-01

    The current large-eddy simulation (LES) research makes use of the contravariant components as the dependent variables on a staggered grid system for the discretisation of the governing equations in curvilinear coordinates. This technology provides a possibility to investigate efficiently turbulent flows in complex geometries. To test and validate the recently developed in-house LES code, LESSGA (Large-Eddy Simulation on a Staggered Grid Arrangement), numerical simulations were performed for turbulent flows in a concentric annular pipe and transitional flows past an airfoil. In this article, the computed results of flows in a concentric annular pipe with a radius ratio of a = R inner/Router = 0.5 at ? and flows past an SD7003 airfoil at Rec = 60,000 and angle of attack α = 4° are compared with available experimental and DNS data. Technical difficulties experienced are also discussed.

  2. Numerical simulations of the charged-particle flow dynamics for sources with a curved emission surface

    NASA Astrophysics Data System (ADS)

    Altsybeyev, V. V.

    2016-12-01

    The implementation of numerical methods for studying the dynamics of particle flows produced by pulsed sources is discussed. A particle tracking method with so-called gun iteration for simulations of beam dynamics is used. For the space charge limited emission problem, we suggest a Gauss law emission model for precise current-density calculation in the case of a curvilinear emitter. The results of numerical simulations of particle-flow formation for cylindrical bipolar diode and for diode with elliptical emitter are presented.

  3. Parameter Estimation and Confidence Regions in the Method of Light Curve Simulations for the Analysis of Power Density Spectra

    SciTech Connect

    Mueller, M.; Madejski, G.

    2009-05-20

    The Method of Light Curve Simulations is a tool that has been applied to X-ray monitoring observations of Active Galactic Nuclei (AGN) for the characterization of the Power Density Spectrum (PDS) of temporal variability and measurement of associated break frequencies (which appear to be an important diagnostic for the mass of the black hole in these systems as well as their accretion state). It relies on a model for the PDS that is fit to the observed data. The determination of confidence regions on the fitted model parameters is of particular importance, and we show how the Neyman construction based on distributions of estimates may be implemented in the context of light curve simulations. We believe that this procedure offers advantages over the method used in earlier reports on PDS model fits, not least with respect to the correspondence between the size of the confidence region and the precision with which the data constrain the values of the model parameters. We plan to apply the new procedure to existing RXTE and XMM observations of Seyfert I galaxies as well as RXTE observations of the Seyfert II galaxy NGC 4945.

  4. PARAMETER ESTIMATION AND CONFIDENCE REGIONS IN THE METHOD OF LIGHT-CURVE SIMULATIONS FOR THE ANALYSIS OF POWER DENSITY SPECTRA

    SciTech Connect

    Mueller, Martin; Madejski, Greg

    2009-07-20

    The method of light-curve simulations is a tool that has been applied to X-ray monitoring observations of active galactic nuclei for the characterization of the power density spectrum (PDS) of temporal variability and measurement of associated break frequencies (which appear to be an important diagnostic for the mass of the black hole in these systems as well as their accretion state). It relies on a model for the PDS that is fitted to the observed data. The determination of confidence regions on the fitted model parameters is of particular importance, and we show how the Neyman construction based on distributions of estimates may be implemented in the context of light-curve simulations. We believe that this procedure offers advantages over the method used in earlier reports on PDS model fits, not least with respect to the correspondence between the size of the confidence region and the precision with which the data constrain the values of the model parameters. We plan to apply the new procedure to existing RXTE and XMM-Newton observations of Seyfert I galaxies as well as RXTE observations of the Seyfert II galaxy NGC 4945.

  5. Parameter Estimation and Confidence Regions in the Method of Light-Curve Simulations for the Analysis of Power Density Spectra

    NASA Astrophysics Data System (ADS)

    Mueller, Martin; Madejski, Greg

    2009-07-01

    The method of light-curve simulations is a tool that has been applied to X-ray monitoring observations of active galactic nuclei for the characterization of the power density spectrum (PDS) of temporal variability and measurement of associated break frequencies (which appear to be an important diagnostic for the mass of the black hole in these systems as well as their accretion state). It relies on a model for the PDS that is fitted to the observed data. The determination of confidence regions on the fitted model parameters is of particular importance, and we show how the Neyman construction based on distributions of estimates may be implemented in the context of light-curve simulations. We believe that this procedure offers advantages over the method used in earlier reports on PDS model fits, not least with respect to the correspondence between the size of the confidence region and the precision with which the data constrain the values of the model parameters. We plan to apply the new procedure to existing RXTE and XMM-Newton observations of Seyfert I galaxies as well as RXTE observations of the Seyfert II galaxy NGC 4945.

  6. Anterior canal BPPV and apogeotropic posterior canal BPPV: two rare forms of vertical canalolithiasis.

    PubMed

    Califano, L; Salafia, F; Mazzone, S; Melillo, M G; Califano, M

    2014-06-01

    Posterior canal benign paroxysmal positional vertigo (BPPV) is the most frequent form of BPPV. It is characterized by a paroxysmal positioning nystagmus evoked through Dix-Hallpike and Semont positioning tests. Anterior canal BPPV (AC) is more rare than posterior canal BPPV; it presents a prevalent down beating positioning nystagmus, with a torsional component clockwise for the left canal, counterclockwise for the right canal. Due to the possible lack of the torsional component, it is sometimes difficult to identify the affected ear. An apogeotropic variant of posterior BPPV (APC) has recently been described, characterised by a paroxysmal positional nystagmus in the opposite direction to the one evoked in posterior canal BPPV: the linear component is down-beating, the torsional component is clockwise for the right canal, counter-clockwise for the left canal, so that a contra-lateral anterior canal BPPV could be simulated. During a 16 month period, of 934 BPPV patients observed, the authors identified 23 (2.5%) cases of apogeotropic posterior canal BPPV and 11 (1.2%) cases of anterior canal BPPV, diagnosed using the specific oculomotor patterns described in the literature. Anterior canal BPPV was treated with the repositioning manoeuvre proposed by Yacovino, which does not require identification of the affected side, whereas apogeotropic posterior canal BPPV was treated with the Quick Liberatory Rotation manoeuvre for the typical posterior canal BPPV, since in the Dix-Hallpike position otoliths are in the same position if they come either from the ampullary arm or from the non-ampullary arm. The direct resolution of BPPV (one step therapy) was obtained in 12/34 patients, 8/23 patients with APC and 4/11 patients with AC; canalar conversion into typical posterior canal BPPV, later treated through Quick Liberatory Rotation (two-step therapy), was obtained in 19 patients,14/23 with APC and 5/11 with AC. Three patients were lost to follow-up. Considering the effects of

  7. Effect of motion cues during complex curved approach and landing tasks: A piloted simulation study

    NASA Technical Reports Server (NTRS)

    Scanlon, Charles H.

    1987-01-01

    A piloted simulation study was conducted to examine the effect of motion cues using a high fidelity simulation of commercial aircraft during the performance of complex approach and landing tasks in the Microwave Landing System (MLS) signal environment. The data from these tests indicate that in a high complexity MLS approach task with moderate turbulence and wind, the pilot uses motion cues to improve path tracking performance. No significant differences in tracking accuracy were noted for the low and medium complexity tasks, regardless of the presence of motion cues. Higher control input rates were measured for all tasks when motion was used. Pilot eye scan, as measured by instrument dwell time, was faster when motion cues were used regardless of the complexity of the approach tasks. Pilot comments indicated a preference for motion. With motion cues, pilots appeared to work harder in all levels of task complexity and to improve tracking performance in the most complex approach task.

  8. Impact of sample geometry on the measurement of pressure-saturation curves: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Moura, M.; Fiorentino, E.-A.; Mâløy, K. J.; Schäfer, G.; Toussaint, R.

    2015-11-01

    In this paper, we study the influence of sample geometry on the measurement of pressure-saturation relationships, by analyzing the drainage of a two-phase flow from a quasi-2-D random porous medium. The medium is transparent, which allows for the direct visualization of the invasion pattern during flow, and is initially saturated with a viscous liquid (a dyed glycerol-water mix). As the pressure in the liquid is gradually reduced, air penetrates from an open inlet, displacing the liquid which leaves the system from an outlet on the opposite side. Pressure measurements and images of the flow are recorded and the pressure-saturation relationship is computed. We show that this relationship depends on the system size and aspect ratio. The effects of the system's boundaries on this relationship are measured experimentally and compared with simulations produced using an invasion percolation algorithm. The pressure build up at the beginning and end of the invasion process are particularly affected by the boundaries of the system whereas at the central part of the model (when the air front progresses far from these boundaries), the invasion happens at a statistically constant capillary pressure. These observations have led us to propose a much simplified pressure-saturation relationship, valid for systems that are large enough such that the invasion is not influenced by boundary effects. The properties of this relationship depend on the capillary pressure thresholds distribution, sample dimensions, and average pore connectivity and its applications may be of particular interest for simulations of two-phase flow in large porous media.

  9. Anisotropic post-yield response of cancellous bone simulated by stress-strain curves of bulk equivalent structures.

    PubMed

    Tsouknidas, Alexander; Maliaris, Georgios; Savvakis, Savvas; Michailidis, Nikolaos

    2015-01-01

    During the last decade, finite element (FE) modelling has become ubiquitous in understanding complex mechanobiological phenomena, e.g. bone-implant interactions. The extensive computational effort required to achieve biorealistic results when modelling the post-yield behaviour of microstructures like cancellous bone is a major limitation of these techniques. This study describes the anisotropic biomechanical response of cancellous bone through stress-strain curves of equivalent bulk geometries. A cancellous bone segment, reverse engineered by micro computed tomography, was subjected to uniaxial compression. The material's constitutive law, obtained by nano-indentations, was considered during the simulation of the experimental process. A homodimensionally bulk geometry was employed to determine equivalent properties, resulting in a similar anisotropic response to the trabecular structure. The experimental verification of our model sustained that the obtained stress-strain curves can adequately reflect the post-yield behaviour of the sample. The introduced approach facilitates the consideration of nonlinearity and anisotropy of the tissue, while reducing the geometrical complexity of the model to a minimum.

  10. Root canal irrigants

    PubMed Central

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

  11. 14. Junction of the Tempe Canal and Western Canal, looking ...

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

    14. Junction of the Tempe Canal and Western Canal, looking north. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  12. Bitter Root Irrigation district canal, looking east, typical section (canal ...

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

    Bitter Root Irrigation district canal, looking east, typical section (canal full) - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  13. The Comparative Efficacy of Different Files in The Removal of Different Sealers in Simulated Root Canal Retreatment- An In-vitro Study

    PubMed Central

    Kanaparthy, Aruna

    2016-01-01

    Introduction Root canal treatment enjoys a high success rate all over the world and has saved billions of teeth from extraction. However, there are instances of failure, the main causes being insufficient cleaning and inadequate obturation. In such cases the most conservative treatment option would be non-surgical retreatment. It requires regaining access to the entire root canal system through removal of the original root canal filling thus permitting further cleaning and re- obturation. Removal of gutta-percha and sealer becomes a critical step to gain access to the root canal system, remove necrotic tissue debris, bacteria and infected dentin. Aim To compare and evaluate the efficacy of manual hand Hedstrom files and two rotary retreatment file systems ProTaper Universal retreatment files and MtwoR (retreatment) files in the removal of root canal filling material during root canal retreatment and the influence of the type of sealers zinc oxide eugenol and AH plus on the presence of remaining debris in the reinstrumented canals in the apical, middle and coronal third. Materials and Methods Sixty single rooted human premolar teeth were divided into 3 Groups of 20 teeth each Group I (20 Teeth): prepared using hand K Files, Group II (20 Teeth): prepared using ProTaper rotary system and Group III (20 Teeth): prepared using Mtwo rotary system. In Groups- IA, IIA, IIIA: (10 teeth each) Obturation was done using Zinc Oxide Eugenol sealer and gutta percha. In Groups- IB, IIB, IIIB: (10 teeth each) obturation was done with AH Plus sealer and gutta percha. All the teeth were subjected to retreatment. Groups IA and IB with Hedstrom files, Groups IIA and IIB with ProTaper retreatment files and for Groups IIIA and IIIB with Mtwo retreatment Files. The roots were longitudinally split and were observed under a stereomicroscope for remaining amount of filling material on the canal walls. Statistical analysis was done using One–way ANOVA (Analysis of variance) test and Tukey

  14. An In Vitro Comparative Study of Intracanal Fluid Motion and Wall Shear Stress Induced by Ultrasonic and Polymer Rotary Finishing Files in a Simulated Root Canal Model

    PubMed Central

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software. PMID:22461994

  15. An in vitro comparative study of intracanal fluid motion and wall shear stress induced by ultrasonic and polymer rotary finishing files in a simulated root canal model.

    PubMed

    Koch, Jon; Borg, John; Mattson, Abby; Olsen, Kris; Bahcall, James

    2012-01-01

    Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

  16. Analysis of the terrestrial ion foreshock: 2D Full-Particle simulation of a curved supercritical shock

    NASA Astrophysics Data System (ADS)

    Lembege, B.; Savoini, P.; Stienlet, J.

    2013-05-01

    Two distinct ion populations backstreaming into the solar wind have been clearly evidenced by various space missions within the quasi-perpendicular region of the ion foreshock located upstream of the Earth's Bow shock (i.e. for 45° ≤ Theta_Bn ≤ 90°, where Theta_Bn is the angle between the shock normal and the upstream magnetostatic field): (i) field-aligned ion beams (« FAB ») characterized by a gyrotropic distribution, and (ii) gyro-phase bunched ions («GPB »), characterized by a NON gyrotropic distribution. The origin of these backstreaming ions has not been clearly identified and is presently analyzed with the help of 2D PIC simulation of a curved shock, where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described within a self consistent approach. Present simulations evidence that these two populations can be effectively created directly by the shock front without invoking microinstabilities. The analysis of both individual and statistical ion trajectories evidences that: (i) two new parameters, namely the interaction time DT_inter and distance of penetration L_depth into the shock wave, play a key role and allow to discriminate these two populations. "GPB" population is characterized by a very short interaction time (DT_inter = 1 to 2 Tci) in comparison to the "FAB" population (DT_inter = 2 Tci to 10 Tci) which moves back and forth between the upstream edge of the shock front and the overshoot, where tci is the upstream ion gyroperiod. (ii) the importance of the injection angle (i.e. the angle between the normal of the shock front and the gyration velocity when ions reach the shock) to understand how the reflection process takes place. (iii) "FAB" population drifts along the curved shock front scanning a large Theta_Bn range from 90°. (iv) "GPB" population is embedded within the "FAB" population near the shock front which explains the difficulty to identify such a population in the experimental

  17. The anomalous canal between two accessory foramina on the mandibular ramus: the temporal crest canal

    PubMed Central

    Han, S-S; Hwang, J-J

    2014-01-01

    Objectives: The temporal crest canal (TCC) is a variation of the bony canal with two accessory foramina that correspond to an entrance and an exit on the mandibular ramus. This study investigated the anatomical characteristics of the TCC using CBCT. Methods: The study population consisted 446 patients who had undergone CBCT. Sagittal, cross-sectional and three-dimensional images were evaluated for the presence of a TCC. The canals were classified into two types according to the configuration, and the location of the posterior accessory foramen of the TCC was also recorded. Results: 6 TCCs were present in 4 of 446 patients (0.90% of the total population). All of the TCCs were observed in males, and all of the posterior foramina were located superior to the mandibular foramina on the medial aspect of the mandibular ramus. There were five noticeably curved and increasingly narrow canals (Type 1) and one slightly curved and uniformly wide canal (Type 2). Conclusions: Precise knowledge of the TCC is clinically important for suitable local anaesthetic nerve block and the planning of surgical procedures that involve the mandibular ramus. Three-dimensional images of CBCT data are particularly effective for confirming the presence of this variation. PMID:24959708

  18. Numerical simulation of peristaltic flow of a biorheological fluid with shear-dependent viscosity in a curved channel.

    PubMed

    Ali, N; Javid, K; Sajid, M; Anwar Bég, O

    2016-01-01

    Peristaltic motion of a non-Newtonian Carreau fluid is analyzed in a curved channel under the long wavelength and low Reynolds number assumptions, as a simulation of digestive transport. The flow regime is shown to be governed by a dimensionless fourth-order, nonlinear, ordinary differential equation subject to no-slip wall boundary conditions. A well-tested finite difference method based on an iterative scheme is employed for the solution of the boundary value problem. The important phenomena of pumping and trapping associated with the peristaltic motion are investigated for various values of rheological parameters of Carreau fluid and curvature of the channel. An increase in Weissenberg number is found to generate a small eddy in the vicinity of the lower wall of the channel, which is enhanced with further increase in Weissenberg number. For shear-thinning bio-fluids (power-law rheological index, n < 1) greater Weissenberg number displaces the maximum velocity toward the upper wall. For shear-thickening bio-fluids, the velocity amplitude is enhanced markedly with increasing Weissenberg number.

  19. Bush Canal Floodgate Study

    DTIC Science & Technology

    2009-07-01

    ER D C/ CH L TR -0 9 -9 Bush Canal Floodgate Study Tate O. McAlpin, Rutherford C. Berger, and Amena M. Henville July 2009 C oa st...al a n d H yd ra u lic s La b or at or y Approved for public release; distribution is unlimited. ERDC/CHL TR-09-9 July 2009 Bush Canal ...LA 70118-3651 Under Military Interdepartmental Purchase Request (MIPR) W42HEM60734548, “H&H Modeling of Bush Canal /Morganza to the Gulf” ERDC/CHL

  20. Simulation of dissolved oxygen and biochemical oxygen demand, Plantation Canal, Broward County, Florida with an evaluation of the QUAL-I model for use in south Florida

    USGS Publications Warehouse

    Russo, Thomas N.; McQuivey, Raul S.

    1975-01-01

    A mathematical model; QUAL-I, developed by the Texas Water Development Board, was evaluated as a management tool in predicting the spatial and temporal distribution of dissolved oxygen and biochemical oxygen demand in Plantation Canal. Predictions based on the QUAL-I model, which was verified only against midday summer-flow conditions, showed that improvement of quality of inflows from sewage treatment plants and use of at least 130 cubic feet per second of dilution water would improve water quality in the canal significantly. The model was not fully amenable to use on Plantation Canal because: (1) it did not consider photosynthetic production, nitrification, and benthic oxygen demand as sources and sinks of oxygen; (2) the model assumptions of complete mixing, transport, and steady state were not met; and (3) the data base was inadequate because it consisted of only one set of data for each case. However, it was felt that meaningful results could be obtained for some sets of conditions. (Woodard-USGS)

  1. Experimental depth dose curves of a 67.5 MeV proton beam for benchmarking and validation of Monte Carlo simulation

    PubMed Central

    Faddegon, Bruce A.; Shin, Jungwook; Castenada, Carlos M.; Ramos-Méndez, José; Daftari, Inder K.

    2015-01-01

    Purpose: To measure depth dose curves for a 67.5 ± 0.1 MeV proton beam for benchmarking and validation of Monte Carlo simulation. Methods: Depth dose curves were measured in 2 beam lines. Protons in the raw beam line traversed a Ta scattering foil, 0.1016 or 0.381 mm thick, a secondary emission monitor comprised of thin Al foils, and a thin Kapton exit window. The beam energy and peak width and the composition and density of material traversed by the beam were known with sufficient accuracy to permit benchmark quality measurements. Diodes for charged particle dosimetry from two different manufacturers were used to scan the depth dose curves with 0.003 mm depth reproducibility in a water tank placed 300 mm from the exit window. Depth in water was determined with an uncertainty of 0.15 mm, including the uncertainty in the water equivalent depth of the sensitive volume of the detector. Parallel-plate chambers were used to verify the accuracy of the shape of the Bragg peak and the peak-to-plateau ratio measured with the diodes. The uncertainty in the measured peak-to-plateau ratio was 4%. Depth dose curves were also measured with a diode for a Bragg curve and treatment beam spread out Bragg peak (SOBP) on the beam line used for eye treatment. The measurements were compared to Monte Carlo simulation done with geant4 using topas. Results: The 80% dose at the distal side of the Bragg peak for the thinner foil was at 37.47 ± 0.11 mm (average of measurement with diodes from two different manufacturers), compared to the simulated value of 37.20 mm. The 80% dose for the thicker foil was at 35.08 ± 0.15 mm, compared to the simulated value of 34.90 mm. The measured peak-to-plateau ratio was within one standard deviation experimental uncertainty of the simulated result for the thinnest foil and two standard deviations for the thickest foil. It was necessary to include the collimation in the simulation, which had a more pronounced effect on the peak-to-plateau ratio for the

  2. Experimental depth dose curves of a 67.5 MeV proton beam for benchmarking and validation of Monte Carlo simulation

    SciTech Connect

    Faddegon, Bruce A. Ramos-Méndez, José; Daftari, Inder K.; Shin, Jungwook; Castenada, Carlos M.

    2015-07-15

    Purpose: To measure depth dose curves for a 67.5 ± 0.1 MeV proton beam for benchmarking and validation of Monte Carlo simulation. Methods: Depth dose curves were measured in 2 beam lines. Protons in the raw beam line traversed a Ta scattering foil, 0.1016 or 0.381 mm thick, a secondary emission monitor comprised of thin Al foils, and a thin Kapton exit window. The beam energy and peak width and the composition and density of material traversed by the beam were known with sufficient accuracy to permit benchmark quality measurements. Diodes for charged particle dosimetry from two different manufacturers were used to scan the depth dose curves with 0.003 mm depth reproducibility in a water tank placed 300 mm from the exit window. Depth in water was determined with an uncertainty of 0.15 mm, including the uncertainty in the water equivalent depth of the sensitive volume of the detector. Parallel-plate chambers were used to verify the accuracy of the shape of the Bragg peak and the peak-to-plateau ratio measured with the diodes. The uncertainty in the measured peak-to-plateau ratio was 4%. Depth dose curves were also measured with a diode for a Bragg curve and treatment beam spread out Bragg peak (SOBP) on the beam line used for eye treatment. The measurements were compared to Monte Carlo simulation done with GEANT4 using TOPAS. Results: The 80% dose at the distal side of the Bragg peak for the thinner foil was at 37.47 ± 0.11 mm (average of measurement with diodes from two different manufacturers), compared to the simulated value of 37.20 mm. The 80% dose for the thicker foil was at 35.08 ± 0.15 mm, compared to the simulated value of 34.90 mm. The measured peak-to-plateau ratio was within one standard deviation experimental uncertainty of the simulated result for the thinnest foil and two standard deviations for the thickest foil. It was necessary to include the collimation in the simulation, which had a more pronounced effect on the peak-to-plateau ratio for the

  3. The Semicircular Canal Microphonic

    NASA Technical Reports Server (NTRS)

    Rabbitt, R. D.; Boyle, R.; Highstein, S. M.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Present experiments were designed to quantify the alternating current (AC) component of the semicircular canal microphonic for angular motion stimulation as a function of stimulus frequency and amplitude. The oyster toadfish, Opsanus tau, was used as the experimental model. Calibrated mechanical indentation of the horizontal canal duct was used as a stimulus to generate hair-cell and afferent responses reproducing those present during head rotation. Sensitivity to polarization of the endolymph DC voltage re: perilymph was also investigated. Modulation of endolymph voltage was recorded using conventional glass electrodes and lock-in amplification over the frequency range 0.2-80 Hz. Access to the endolymph for inserting voltage recording and current passing electrodes was obtained by sectioning the anterior canal at its apex and isolating the cut ends in air. For sinusoidal stimulation below approx.10 Hz, the horizontal semicircular canal AC microphonic was nearly independent of stimulus frequency and equal to approximately 4 microV per micron indent (equivalent to approx. 1 microV per deg/s). A saturating nonlinearity decreasing the microphonic gain was present for stimuli exceeding approx.3 micron indent (approx. 12 deg/s angular velocity). The phase was not sensitive to the saturating nonlinearity. The microphonic exhibited a resonance near 30Hz consistent with basolateral current hair cell resonance observed previously in voltage-clamp records from semicircular canal hair cells. The magnitude and phase of the microphonic exhibited sensitivity to endolymphatic polarization consistent with electro-chemical reversal of hair cell transduction currents.

  4. 55. View of junction of unlined canal and lined canal, ...

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

    55. View of junction of unlined canal and lined canal, looking southwest. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  5. 54. View of junction of unlined canal and lined canal, ...

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

    54. View of junction of unlined canal and lined canal, looking southwest. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  6. A novel approach in assessment of root canal curvature

    PubMed Central

    Sadeghi, Shiva; Poryousef, Vahideh

    2009-01-01

    Introduction: The purpose of this in vitro study was to introduce a new method to describe root canal curvatures and to assess the degree of curvature of human permanent mandibular teeth with curved root canals. Materials and Methods: One hundred and thirty five mesial root canals of mandibular first and second molar teeth were selected. Access cavities were prepared. After inserting a K-file size #10 into each canal, radiographs were taken. Canal curvature was determined by measuring the Schneider angle, canal access angle, as well as the canal radius, length, height and curvature starting distance on scanned radiographs using a computerized image processing system. Data was evaluated statistically using Pearson correlation. Results: The mean canal access angle (CAA) and Schneider angle (S) were 8.04◦ (3.46) and 19◦ (6.99), respectively. The Pearson correlation analysis found significant positive correlation between S and CAA (r=0.826, P<0.0001). Negative correlations were found between radius and length (r= –0.4, P<0.0001), radius and Schneider angle (r= –0.4, P<0.0001), radius and CAA (r= –0.24, P=0.004) and CAA and curvature starting distance (r= 0.4, P<0.0001). There was no correlation between height and distance (r=0.013, P=0.789), as well as CAA and height (r=0.654, P=0.001). Conclusion: Under the limitations of this study, the results indicated that the shape of root canal curvature can be more accurately described using two angles, Schneider in combination with Canal access angle. The related parameters included radius, length, distance and height of curvature. [Iranian Endodontic Journal 2009;4(4):131-4] PMID:24019833

  7. A Molecular Dynamics simulation of Hugoniot curves of HMX using ReaxFF and its application in SPH modeling of macroscale terminal effects

    NASA Astrophysics Data System (ADS)

    Liu, Gui-Rong; Wang, Gangyu; Peng, Qing; de, Suvranu

    2015-06-01

    HMX is a widely used high explosive. Hugoniot curve is a valuable tool for analyzing the equations of state, and is of importance for all energetic materials including HMX. The Hugoniot curves serve as one of the key character in continuum modeling of high explosives. It can be obtained from experimental measurements, and recently also from computational studies. In this study, the Hugoniot curve of HMX is calculated using a multi-scale shock technique via Molecular Dynamics (MD) simulations, where the reactive force field ReaxFF is obtained from Quantum Mechanics calculations and tailored for HMX. It is found that our MD Hugoniot curve of HMX from the optimized ReaxFF potential agree well with experiments. The MD Hugoniot curve of HMX is also incorporated in our in-house Smoothed Particle Hydrodynamics (SPH) code for the modeling of the macro-scale explosive behaviors of HMX explosives and HMX cased in a 3D cylinder. The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant HDTRA1-13-1-0025.

  8. Polyacrylamide Transport in Water Delivery Canals

    NASA Astrophysics Data System (ADS)

    Chen, L.; Zhu, J.; Young, M.

    2007-12-01

    Linear, anionic polyacrylamide (PAM) is being considered in the western United States as a technology to reduce seepage in unlined water delivery canals. A broad laboratory and field testing program has been undertaken to understand the benefits and potential environmental impacts of PAM use. The ability to predict the fate and transport of PAM in water delivery canals could prove to be a useful planning tool for PAM application. However, one key area of uncertainty of this type of canal treatment is the hydration, reaction, and settling rates of PAM after the dry powder is added to the canal water. In this study, we have developed a model that incorporates a number of known physical and chemical processes that can affect PAM transport, such as convection, dispersion, dissolution, flocculation, and settling, while solving the governing convection-dispersion transport equation. The model uses a mixed analytical and advanced numerical approach, and implements a transient partitioning of PAM mass between the canal water, the substrate soil, and potentially to open water bodies downstream of the application point. All source terms are modeled based on physical and chemical mechanisms as well as laboratory or field determined parameters. To more closely simulate field treatment of some canals, where PAM application moves upstream in time, the model is capable of implementing either a fixed or mobile upper boundary. In the latter treatment, the PAM can be added discretely or continuously in both time and space. A number of test situations have been simulated thus far, including theoretical and hypothetical cases for a wide range of conditions. The model also performed well when predicting PAM concentrations from a full-scale canal treatment experiment. The model provides a useful tool for predicting PAM fate and transport in water delivery canals, and therefore can play an important role in evaluating the efficacy of PAM application for water resources management

  9. Curved Beam Computed Tomography based Structural Rigidity Analysis of Bones with Simulated Lytic Defect: A Comparative Study with Finite Element Analysis

    PubMed Central

    Oftadeh, R.; Karimi, Z.; Villa-Camacho, J.; Tanck, E.; Verdonschot, N.; Goebel, R.; Snyder, B. D.; Hashemi, H. N.; Vaziri, A.; Nazarian, A.

    2016-01-01

    In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections. Experimental results were compared to the results obtained from FEA and CTRA. The failure loads predicated by curved beam CTRA and FEA are in agreement with experimental results. The results also show that the proposed method is an efficient and reliable method to find both the location and magnitude of failure load. Moreover, the results show that the proposed curved CTRA outperforms the regular straight beam CTRA, which ignores the bone intrinsic curvature and can be used as a useful tool in clinical practices. PMID:27585495

  10. Numerical simulations of rubber networks at moderate to high tensile strains using a purely enthalpic force extension curve for individual chains

    SciTech Connect

    Hanson, David Edward

    2009-01-01

    We report the results of numerical simulations of random, three-dimensional, periodic, tetrafunctional networks in response to a volume-preserving tensile strain. For the intranode force, we use a polynomial fit to a purely enthalpic ab initio force extension curve for extended polyisoprene. The simulation includes a relaxation procedure to minimize the node forces and enforces chain rupture when the extension of a network chain reaches the ab initio rupture strain. For the reasonable assumption that the distribution of network chain lengths is Gaussian, we find that the calculated snap-back velocity, temperature increase due to chain ruptures and predicted tensile stress versus strain curve are consistent with experimental data in the moderate to high extension regime. Our results show that a perfect tetrafunctional polyisoprene network is extremely robust, capable of supporting tensile stresses at least a factor of 10 greater than what is observed experimentally.

  11. 56. View of lined canal looking east toward unlined canal, ...

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

    56. View of lined canal looking east toward unlined canal, from road bridge crossing lined canal. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  12. Love canal questions

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    The Environmental Protection Agency (EPA) conducted a 3-month monitoring study of the Love Canal area near Niagara Falls, N.Y., after the federal government pronounced that a potential health risk existed due to chemical waste dumps. In 1982 the Department of Health and Human Services (HHS) decided that the area was habitable, subject to implementation of effective safeguards against leakage from the canal and to cleaning up of the contaminants. Now, the Congressional Office of Technology Assessment (OTA) has announced that, with the information available, it is not possible to demonstrate with certainty that unsafe levels do not exist within the so-called “emergency declaration area” (EDA).

  13. Effectiveness of conventional syringe irrigation, vibringe, and passive ultrasonic irrigation performed with different irrigation regimes in removing triple antibiotic paste from simulated root canal irregularities

    PubMed Central

    Topçuoğlu, Hüseyin Sinan; Aktı, Ahmet; Topçuoğlu, Gamze; Düzgün, Salih; Ulusan, Özge; Akpek, Firdevs

    2016-01-01

    Background: This study evaluated the efficacy of a sonic device (Vibringe), passive ultrasonic irrigation (PUI), and conventional syringe irrigation (CSI) in the removal of triple antibiotic paste (TAP) from artificial standardized grooves in the apical and coronal thirds of a root canal. Materials and Methods: One-hundred eighteen root canals were prepared using the ProTaper system. The roots were split longitudinally, and a standardized groove was prepared in the apical and coronal parts of one segment. The grooves were filled with TAP, and the roots were reassembled. The roots were randomly divided into nine experimental groups and two control groups, according to the following irrigation methods: (1) CSI with sodium hypochlorite (NaOCl) + ethylenediaminetetraacetic acid (EDTA), (2) CSI/EDTA, (3) CSI/NaOCl, (4) PUI/NaOCl + EDTA, (5) PUI/EDTA, (6) PUI/NaOCl, (7) Vibringe/NaOCl + EDTA, (8) Vibringe/EDTA, and (9) Vibringe/NaOCl. The amount of remaining medicament was evaluated under a stereomicroscope. Results: In the apical third, Vibringe/NaOCl + EDTA and PUI/NaOCl + EDTA were superior to the other groups (P < 0.05); there was no significant difference between the other experimental groups (P > 0.05). In the coronal third, there was no significant difference between the experimental groups (P > 0.05). Conclusions: The use of the NaOCl/EDTA combination together with sonic or ultrasonic agitation improved the removal of TAP from the apical third. PMID:27563179

  14. A novel model for testing the efficiency of removal of calcium hydroxide from complex root canal anatomies.

    PubMed

    Küçükkaya Eren, Selen; Aksel, Hacer; Parashos, Peter

    2017-04-01

    The purpose of this study was to evaluate the efficacy of several irrigation protocols in the removal of calcium hydroxide [Ca(OH)2 ] from simulated internal root resorption cavities in a complex root canal anatomy model. The 20° to 35° curved mesiobuccal roots of 94 maxillary molars were sectioned longitudinally; internal resorption cavities were prepared in the apical third of the canal walls. Calcium hydroxide was placed into the cavities and the root halves reassembled. Four teeth were used as controls, and 90 teeth were randomly divided into six experimental groups (n = 15), according to the irrigation protocols used: syringe irrigation; H2 O2 (HP); Navitip FX; Vibringe-syringe; Vibringe-NaviTip FX; ultrasonically activated irrigation (UAI) using an ultrasonic K-file. In the HP group, 2.5% NaOCl and 3% H2 O2 were used, while 2.5% NaOCl and 17% EDTA were used in the remaining groups. Stereomicroscope images and radiographs were used to measure the remaining Ca(OH)2 . The model proved to be suitable for simulating complex anatomy. Positive correlation was found between stereomicroscope and radiographic analyses (P < 0.05). UAI removed significantly more Ca(OH)2 than the other experimental groups (P < 0.05). The HP group was the least efficient protocol (P < 0.05). It would appear that a reliable model has been developed that simulates complex root canal anatomy. Irrigant activation protocols enhanced Ca(OH)2 removal.

  15. Applications of Sphere Geometry in Canal Surface Design

    DTIC Science & Technology

    2000-01-01

    surface, the problem was solved by Pottmann and Peternell [11]. They proved the surprising result that any canal surface with rational spine curve m(t) and... Peternell [11]. In this paper we will follow the second option. It results in the concept of Minkowski Pythagorean Hodograph curves. §5. Minkowski...Boehm, General cyclides, Comput. Aided Geom. Design 15 (1998), 699-710. 11. Peternell , M., and H. Pottmann, Computing rational parametrizations of

  16. Panama: Owning the Canal

    DTIC Science & Technology

    2014-03-01

    construction materials , waiving tariffs on Panamanian goods entering the zone, allowing Panamanians into zone hospitals and constructing a highway for more...landslide in the Gaillard Cut (also called Culebra Cut), dumping about one half million cubic yards of earth material and debris into the Panama Canal...temporary cautionary transit procedures in order to keep the channel safely operating while cleanup was ongoing. The PCC implemented landslide control

  17. Derivation of a Provisional, Age-dependent, AIS2+ Thoracic Risk Curve for the THOR50 Test Dummy via Integration of NASS Cases, PMHS Tests, and Simulation Data.

    PubMed

    Laituri, Tony R; Henry, Scott; El-Jawahri, Raed; Muralidharan, Nirmal; Li, Guosong; Nutt, Marvin

    2015-11-01

    A provisional, age-dependent thoracic risk equation (or, "risk curve") was derived to estimate moderate-to-fatal injury potential (AIS2+), pertaining to men with responses gaged by the advanced mid-sized male test dummy (THOR50). The derivation involved two distinct data sources: cases from real-world crashes (e.g., the National Automotive Sampling System, NASS) and cases involving post-mortem human subjects (PMHS). The derivation was therefore more comprehensive, as NASS datasets generally skew towards younger occupants, and PMHS datasets generally skew towards older occupants. However, known deficiencies had to be addressed (e.g., the NASS cases had unknown stimuli, and the PMHS tests required transformation of known stimuli into THOR50 stimuli). For the NASS portion of the analysis, chest-injury outcomes for adult male drivers about the size of the THOR50 were collected from real-world, 11-1 o'clock, full-engagement frontal crashes (NASS, 1995-2012 calendar years, 1985-2012 model-year light passenger vehicles). The screening for THOR50-sized men involved application of a set of newly-derived "correction" equations for self-reported height and weight data in NASS. Finally, THOR50 stimuli were estimated via field simulations involving attendant representative restraint systems, and those stimuli were then assigned to corresponding NASS cases (n=508). For the PMHS portion of the analysis, simulation-based closure equations were developed to convert PMHS stimuli into THOR50 stimuli. Specifically, closure equations were derived for the four measurement locations on the THOR50 chest by cross-correlating the results of matched-loading simulations between the test dummy and the age-dependent, Ford Human Body Model. The resulting closure equations demonstrated acceptable fidelity (n=75 matched simulations, R2≥0.99). These equations were applied to the THOR50-sized men in the PMHS dataset (n=20). The NASS and PMHS datasets were combined and subjected to survival

  18. Laboratory Simulation of Urban Runoff and Estimation of Runoff Hydrographs with Experimental Curve Numbers Implemented in USEPA SWMM

    EPA Science Inventory

    The prognostic capabilities of a lumped hydrologic modeling approach may be complicated by routing and connectivity among infiltrative and impervious surfaces. We used artificial rainfall to generate runoff from impervious and bare soil boxes arranged in series to simulate differ...

  19. Modeling and measurement of root canal using stereo digital radiography

    NASA Astrophysics Data System (ADS)

    Analoui, Mostafa; Krisnamurthy, Satthya; Brown, Cecil

    2000-04-01

    Determining root canal length is a crucial step in success of root canal treatment. Root canal length is commonly estimated based on pre-operation intraoral radiography. 2D depiction of a 3D object is the primary source of error in this approach. Techniques based on impedance measurement are more accurate than radiographic approaches, but do not offer a method for depicting the shape of canal. In this study, we investigated a stererotactic approach for modeling and measurement of root canal of human dentition. A weakly perspective model approximated the projectional geometry. A series of computer-simulated objects was used to test accuracy of this model as the first step. The, to assess the clinical viability of such an approach, endodontic files inserted in the root canal phantoms were fixed on an adjustable platform between a radiographic cone and an image receptor. Parameters of projection matrix were computed based on the relative positions of image receptors, focal spot, and test objects. Rotating the specimen platform from 0 to 980 degrees at 5-degree intervals set relative angulations for stereo images. Root canal is defined as the intersection of two surfaces defined by each projection. Computation of error for length measurement indicates that for angulations greater than 40 degrees the error is within clinically acceptable ranges.

  20. BINSYN: A Publicly Available Program for Simulating Spectra and Light Curves of Binary Systems with or without Accretion Disks

    NASA Astrophysics Data System (ADS)

    Linnell, Albert P.; DeStefano, Paul; Hubeny, Ivan

    2012-08-01

    The BINSYN program suite, a collection of programs for analysis of binary star systems with or without an optically thick accretion disk, is available for download from a wiki. This article describes the package, including download instructions. BINSYN produces synthetic spectra of individual binary star components plus a synthetic spectrum of the system. If the system includes an accretion disk, BINSYN also produces a separate synthetic spectrum of the disk face and rim. A system routine convolves the synthetic spectra with filter profiles of several photometric standards to produce absolute synthetic photometry output. The package generates synthetic light curves and determines an optimized solution for system parameters. This article includes illustrative literature references that have used the suite, including mass transfer rates in several cataclysmic binary systems.

  1. Simulation of current-voltage curves for inverted planar structure perovskite solar cells using equivalent circuit model with inductance

    NASA Astrophysics Data System (ADS)

    Cojocaru, Ludmila; Uchida, Satoshi; Jayaweera, Piyankarage V. V.; Kaneko, Shoji; Toyoshima, Yasutake; Nakazaki, Jotaro; Kubo, Takaya; Segawa, Hiroshi

    2017-02-01

    Physical modeling of hysteretic behavior in current-voltage (I-V) curves of perovskite solar cells (PSCs) is necessary for further improving their power conversion efficiencies (PCEs). The reduction of hysteresis in inverted planar structure PSCs (p-PSCs) has been achieved by using a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) layer. In the cases, the opposite trend of the I-V hysteresis has been observed where the forward scan shows slightly higher efficiency than the reverse scan. In this paper, an equivalent circuit model with inductance is proposed. This model consists of a Schottky diode involving a parasitic inductance focusing PCBM/Al(Ca) interface and accurately represents the opposite trend of the I-V hysteresis of the p-PSC with an inverted structure.

  2. Simulation of the shape of chaperonins using the small-angle x-ray scattering curves and torus form factor

    SciTech Connect

    Amarantov, S. V.; Naletova, I. N.; Kurochkina, L. P.

    2011-08-15

    The inverse scattering problem has been solved for protein complexes whose surfaces can be described by a set of the simplest doubly connected surfaces in the uniform approximation (a scattering potential inside the molecule is a constant). Solutions of two proteins-well-known GroEL bacterial chaperonin and poor-studied bacteriophage chaperonin, which is a product of 146 gene (gp146)-were taken for the experiment. The shapes of protein complexes have been efficiently reconstructed from the experimental scattering curves. The shell method, the method of the rotation of amino acid sequences with the use of the form factor of an amino acid, and the method of seeking the model parameters of a protein complex with the preliminarily obtained form factor of the model have been used to reconstruct the shape of these particles.

  3. Numerical simulation for peristalsis of Carreau-Yasuda nanofluid in curved channel with mixed convection and porous space

    PubMed Central

    Tanveer, Anum; Hayat, T.; Alsaedi, A.; Ahmad, B.

    2017-01-01

    Main theme of present investigation is to model and analyze the peristaltic activity of Carraeu-Yasuda nanofluid saturating porous space in a curved channel. Unlike the traditional approach, the porous medium effects are characterized by employing modified Darcy’s law for Carreau-Yasuda fluid. To our knowledge this is first attempt in this direction for Carreau-Yasuda fluid. Heat and mass transfer are further considered. Simultaneous effects of heat and mass transfer are examined in presence of mixed convection, viscous dissipation and thermal radiation. The compliant characteristics for channel walls are taken into account. The resulting complex mathematical system has been discussed for small Reynolds number and large wavelength concepts. Numerical approximation to solutions are thus plotted in graphs and the physical description is presented. It is concluded that larger porosity in a medium cause an enhancement in fluid velocity and reduction in concentration. PMID:28151968

  4. Distributed control at Love canal

    SciTech Connect

    McPherson, G.; Rider, G.J.; Sadowski, B.; Moore, M.

    1994-09-01

    Love Canal is known worldwide as the site of one of the worst non-nuclear environmental disasters in modern history. For 12 years, a Niagara Falls, New York chemical company used the canal bed as a chemical dump. This article discusses the computerized control of equipment used to remove the toxic materials from the ground under Love Canal, and how the minimization of maintenance is reducing maintenance costs and increasing operator safety.

  5. Investigating inter-segmental connections between thoracic ganglia in the stick insect by means of experimental and simulated phase response curves.

    PubMed

    Tóth, Tibor I; Grabowska, Martyna; Rosjat, Nils; Hellekes, Katja; Borgmann, Anke; Daun-Gruhn, Silvia

    2015-06-01

    The neuronal networks that control the motion of the individual legs in insects, in particular in the stick insect, are located in the pro-, meso- and meta-thoracic ganglia. They ensure high flexibility of movement control. Thus, the legs can move in an apparently independent way, e.g., during search movements, but also in tight coordination during locomotion. The latter is evidently a very important behavioural mode. It has, therefore, inspired a large number of studies, all aiming at uncovering the nature of the inter-leg coordination. One of the basic questions has been as to how the individual control networks in the three thoracic ganglia are connected to each other. One way to study this problem is to use phase response curves. They can reveal properties of the coupling between oscillatory systems, such as the central pattern generators in the control networks in the thoracic ganglia. In this paper, we report results that we have achieved by means of a combined experimental and modelling approach. We have calculated phase response curves from data obtained in as yet unpublished experiments as well as from those in previously published ones. By using models of the connected pro- and meso-thoracic control networks of the protractor and retractor neuromuscular systems, we have also produced simulated phase response curves and compared them with the experimental ones. In this way, we could gain important information of the nature of the connections between the aforementioned control networks. Specifically, we have found that connections from both the protractor and the retractor "sides" of the pro-thoracic network to the meso-thoracic one are necessary for producing phase response curves that show close similarity to the experimental ones. Furthermore, the strength of the excitatory connections has been proven to be crucial, while the inhibitory connections have essentially been irrelevant. We, thus, suggest that this type of connection might also be present in

  6. Comparison of Curved Root Canals Prepared with Various Chelating Agents

    DTIC Science & Technology

    2012-06-01

    A thesis submitted to the Faculty of the Endodontics Graduate Program Naval Postgraduate Dental School Uniformed Services...Professional Development Center ~ Terry D. Webb, DDS, MS CAPT, DC, USN Chairman, Endodontics Dept. Glen M. Imamura, s: MS CAPT, DC, USN Ch"JiiL=h n...beyond brief excerpts, is with the permission of the copyright owner. Kelli Swenson, DDS, MS Endodontics Department Naval Postgraduate Dental

  7. Using a High-Fidelity Patient Simulator with First-Year Medical Students to Facilitate Learning of Cardiovascular Function Curves

    ERIC Educational Resources Information Center

    Harris, David M.; Ryan, Kathleen; Rabuck, Cynthia

    2012-01-01

    Students are relying on technology for learning more than ever, and educators need to adapt to facilitate student learning. High-fidelity patient simulators (HFPS) are usually reserved for the clinical years of medical education and are geared to improve clinical decision skills, teamwork, and patient safety. Finding ways to incorporate HFPS into…

  8. ASTER Suez Canal

    NASA Technical Reports Server (NTRS)

    2000-01-01

    One of the most important waterways in the world, the Suez Canal runs north to south across the Isthmus of Suez in northeastern Egypt. This image of the canal covers an area 36 kilometers (22 miles) wide and 60 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. It shows the northern part of the canal, with the Mediterranean Sea just visible in the upper right corner. The Suez Canal connects the Mediterranean Sea with the Gulf of Suez, an arm of the Red Sea. The artificial canal provides an important shortcut for ships operating between both European and American ports and ports located in southern Asia, eastern Africa, and Oceania. With a length of about 195 kilometers (121 miles) and a minimum channel width of 60 meters (197 feet), the Suez Canal is able to accommodate ships as large as 150,000 tons fully loaded. Because no locks interrupt traffic on this sea level waterway, the transit time only averages about 15 hours. ASTER acquired this scene on May 19, 2000.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five

  9. 15. ROUTE OF CANAL NORTHWEST OF THE DILLON CEMETERY. CANAL ...

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

    15. ROUTE OF CANAL NORTHWEST OF THE DILLON CEMETERY. CANAL PASSES BELOW HILLSIDE IN FOREGROUND, THROUGH THE LOWER EDGE OF THE TREES ON LEFT, ON FAR SIDE OF SMALL VALLEY JUST RIGHT OF CENTER, AND AROUND THE PROMINENT POINT ON THE RIGHT. VIEW IS TO THE EAST-SOUTHEAST. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  10. Controversy at Love Canal.

    PubMed

    Paigen, B

    1982-06-01

    A cancer researcher reviews the events surrounding the toxic waste contamination at Love Canal with emphasis on the political nature of the controversy about its health impact. Antagonism between the community and the New York State Department of Health was fueled by several factors: the state's awareness that it gained from delay in investigation, disagreement on health problems to be studied, control over the information gathering process, silencing of opposition opinion, and the violation of norms of scientific behavior. The author calls for the establishment of standards of ethical behavior for scientists in such situations, standards for conflict resolution, and means of appeal for those injured.

  11. Simulations of Gamma-Ray Burst Jets in a Stratified External Medium: Dynamics, Afterglow Light Curves, Jet Breaks, and Radio Calorimetry

    NASA Astrophysics Data System (ADS)

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-05-01

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρextvpropr -k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ-1 0. For larger k values, however, the lateral expansion is faster at early times (when Γ > θ-1 0) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θobs <= θ0) than by the slope of the external density profile (for 0 <= k <= 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more

  12. Osmolarity and root canal antiseptics.

    PubMed

    Rossi-Fedele, G; Guastalli, A R

    2014-04-01

    Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: 'osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm'. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, 'in press' and 'early view', and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo-osmosis in root canal disinfection, or osmosis in any further desirable

  13. Models to Estimate Lactation Curves of Milk Yield and Somatic Cell Count in Dairy Cows at the Herd Level for the Use in Simulations and Predictive Models

    PubMed Central

    Græsbøll, Kaare; Kirkeby, Carsten; Nielsen, Søren Saxmose; Halasa, Tariq; Toft, Nils; Christiansen, Lasse Engbo

    2016-01-01

    Typically, central milk recording data from dairy herds are recorded less than monthly. Over-fitting early in lactation periods is a challenge, which we explored in different ways by reducing the number of parameters needed to describe the milk yield and somatic cell count of individual cows. Furthermore, we investigated how the parameters of lactation models correlate between parities and from dam to offspring. The aim of the study was to provide simple and robust models for cow level milk yield and somatic cell count for fitting to sparse data to parameterize herd- and cow-specific simulation of dairy herds. Data from 610 Danish Holstein herds were used to determine parity traits in milk production regarding milk yield and somatic cell count of individual cows. Parity was stratified in first, second, and third and higher for milk, and first to sixth and higher for somatic cell count. Fitting of herd level parameters allowed for cow level lactation curves with three, two, or one parameters per lactation. Correlations of milk yield and somatic cell count were estimated between lactations and between dam and offspring. The shape of the lactation curves varied markedly between farms. The correlation between lactations for milk yield and somatic cell count was 0.2–0.6 and significant on more than 95% of farms. The variation in the daily milk yield was observed to be a source of variation to the somatic cell count, and the total somatic cell count was less correlated with the milk production than somatic cells per milliliter. A positive correlation was found between relative levels of the total somatic cell count and the milk yield. The variation of lactation and somatic cell count curves between farms highlights the importance of a herd level approach. The one-parameter per cow model using a herd level curve allows for estimating the cow production level from first the recording in the parity, while a two-parameter model requires more recordings for a credible

  14. Bradford Curves.

    ERIC Educational Resources Information Center

    Rousseau, Ronald

    1994-01-01

    Discussion of informetric distributions shows that generalized Leimkuhler functions give proper fits to a large variety of Bradford curves, including those exhibiting a Groos droop or a rising tail. The Kolmogorov-Smirnov test is used to test goodness of fit, and least-square fits are compared with Egghe's method. (Contains 53 references.) (LRW)

  15. GAMMA-RAY BURST AFTERGLOW LIGHT CURVES FROM A LORENTZ-BOOSTED SIMULATION FRAME AND THE SHAPE OF THE JET BREAK

    SciTech Connect

    Van Eerten, Hendrik; MacFadyen, Andrew

    2013-04-20

    The early stages of decelerating gamma-ray burst (GRB) afterglow jets have been notoriously difficult to resolve numerically using two-dimensional hydrodynamical simulations even at very high resolution, due to the extreme thinness of the blast wave and high outflow Lorentz factors. However, these resolution issues can be avoided by performing the simulations in a boosted frame, which makes it possible to calculate afterglow light curves from numerically computed flows in sufficient detail to accurately quantify the shape of the jet break and the post-break steepening of the light curve. Here, we study afterglow jet breaks for jets with opening angles of 0.05, 0.1, and 0.2 radians decelerating in a surrounding medium of constant density, observed at various angles ranging from on-axis to the edge of the jet. A single set of scale-invariant functions describing the time evolution of afterglow synchrotron spectral break frequencies and peak flux, depending only on jet opening angle and observer angle, are all that is needed to reconstruct light curves for arbitrary explosion energy, circumburst density and synchrotron particle distribution power law slope p. These functions are presented in the paper. Their time evolutions change directly following the jet break, although an earlier reported temporary post-break steepening of the cooling break is found to have been resolution-induced. We compare synthetic light curves to fit functions using sharp power law breaks as well as smooth power law transitions. We confirm our earlier finding that the measured jet break time is very sensitive to the angle of the observer and can be postponed significantly. We find that the difference in temporal indices across the jet break is larger than theoretically anticipated and is about -(0.5 + 0.5p) below the cooling break and about -(0.25 + 0.5p) above the cooling break, both leading to post-break slopes of roughly about 0.25 - 1.3p, although different observer angles, jet opening

  16. Kinetic analysis of enzyme systems with suicide substrate in the presence of a reversible competitive inhibitor, tested by simulated progress curves.

    PubMed

    Moruno-Dávila, M A; Garrido-del Solo, C; García-Moreno, M; Havsteen, B H; Garcia-Sevilla, F; Garcia-Cánovas, F; Varón, R

    2001-02-01

    The use of suicide substrates remains a very important and useful method in enzymology for studying enzyme mechanisms and designing potential drugs. Suicide substrates act as modified substrates for the target enzymes and bind to the active site. Therefore the presence of a competitive reversible inhibitor decreases the rate of substrate-induced inactivation and protects the enzyme from this inactivation. This lowering on the inactivation rate has evident physiological advantages, since it allows the easy acquisition of experimental data and facilitates kinetic data analysis by providing another variable (inhibitor concentration). However despite the importance of the simultaneous action of a suicide substrate and a competitive reversible inhibition, to date no corresponding kinetic analysis has been carried out. Therefore we present a general kinetic analysis of a Michaelis-Menten reaction mechanism with double inhibition caused by both, a suicide substrate and a competitive reversible inhibitor. We assume rapid equilibrium of the reversible reaction steps involved, while the time course equations for the reaction product have been derived with the assumption of a limiting enzyme. The goodness of the analytical solutions has been tested by comparison with the simulated curves obtained by numerical integration. A kinetic data analysis to determine the corresponding kinetic parameters from the time progress curve of the product is suggested. In conclusion, we present a complete kinetic analysis of an enzyme reaction mechanism as described above in an attempt to fill a gap in the theoretical treatment of this type of system.

  17. A mathematical approach towards simulating a realistic tissue activity curve of 64Cu-ATSM for the purpose of sub-target volume delineation in radiotherapy

    NASA Astrophysics Data System (ADS)

    Dalah, E.; Bradley, D.; Nisbet, A.

    2010-07-01

    One unique feature of positron emission tomography (PET) is that it allows measurements of regional tracer concentration in hypoxic tumour-bearing tissue, supporting the need for accurate radiotherapy treatment planning. Generally the data are taken over multiple time frames, in the form of tissue activity curves (TACs), providing an indication of the presence of hypoxia, the degree of oxygen perfusion, vascular geometry and hypoxia fraction. In order to understand such a complicated phenomenon a number of theoretical studies have attempted to describe tracer uptake in tissue cells. More recently, a novel computerized reaction diffusion equation method developed by Kelly and Brady has allowed simulation of the realistic TACs of 18F-FMISO, with representation of physiological oxygen heterogeneity and tracer kinetics. We present a refinement to the work of Kelly and Brady, with a particular interest in simulating TACs of the most promising hypoxia selective tracer, 64Cu-ATSM, demonstrating its potential role in tumour sub-volume delineation for radiotherapy treatment planning. Simulation results have demonstrated the high contrast of imaging using ATSM, with a tumour to blood ratio ranging 2.24-4.1. Similarly, results of tumour sub-volumes generated using three different thresholding methods were all well correlated.

  18. 173. CANAL TENDER OPERATING LOCK MACHINERY ON THE MORRIS CANAL. ...

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

    173. CANAL TENDER OPERATING LOCK MACHINERY ON THE MORRIS CANAL. AS THE LOCK TENDER TURNS THE CRANK, A SMALL COGGED WHEEL (PINION) ON THE CRANK TURNS A LARGER COGGED WHEEL, (MAIN GEAR). MAIN GEAR ENGAGES A COGGED BAR CALLED A TRAVELLER WHICH MOVES FORWARD OR BACK DEPENDING ON WHICH WAY THE CRANK IS TURNED. CONNECTED TO THE TRAVELLER ARE TO LONG RODS (GATE ARMS) WHICH IN TURN ARE CONNECTED TO THE GATE'S TOP BEAM (ONE FOR EACH GATE). AS THE TRAVELLER MOVES FORWARD THE GATE ARMS EXTEND PUSHING THE GATES OPEN. - Morris Canal, Phillipsburg, Warren County, NJ

  19. Phase transition of Boolean networks with partially nested canalizing functions

    NASA Astrophysics Data System (ADS)

    Jansen, Kayse; Matache, Mihaela Teodora

    2013-07-01

    We generate the critical condition for the phase transition of a Boolean network governed by partially nested canalizing functions for which a fraction of the inputs are canalizing, while the remaining non-canalizing inputs obey a complementary threshold Boolean function. Past studies have considered the stability of fully or partially nested canalizing functions paired with random choices of the complementary function. In some of those studies conflicting results were found with regard to the presence of chaotic behavior. Moreover, those studies focus mostly on ergodic networks in which initial states are assumed equally likely. We relax that assumption and find the critical condition for the sensitivity of the network under a non-ergodic scenario. We use the proposed mathematical model to determine parameter values for which phase transitions from order to chaos occur. We generate Derrida plots to show that the mathematical model matches the actual network dynamics. The phase transition diagrams indicate that both order and chaos can occur, and that certain parameters induce a larger range of values leading to order versus chaos. The edge-of-chaos curves are identified analytically and numerically. It is shown that the depth of canalization does not cause major dynamical changes once certain thresholds are reached; these thresholds are fairly small in comparison to the connectivity of the nodes.

  20. A Review and Comparison of Methods for Recreating Individual Patient Data from Published Kaplan-Meier Survival Curves for Economic Evaluations: A Simulation Study

    PubMed Central

    Wan, Xiaomin; Peng, Liubao; Li, Yuanjian

    2015-01-01

    Background In general, the individual patient-level data (IPD) collected in clinical trials are not available to independent researchers to conduct economic evaluations; researchers only have access to published survival curves and summary statistics. Thus, methods that use published survival curves and summary statistics to reproduce statistics for economic evaluations are essential. Four methods have been identified: two traditional methods 1) least squares method, 2) graphical method; and two recently proposed methods by 3) Hoyle and Henley, 4) Guyot et al. The four methods were first individually reviewed and subsequently assessed regarding their abilities to estimate mean survival through a simulation study. Methods A number of different scenarios were developed that comprised combinations of various sample sizes, censoring rates and parametric survival distributions. One thousand simulated survival datasets were generated for each scenario, and all methods were applied to actual IPD. The uncertainty in the estimate of mean survival time was also captured. Results All methods provided accurate estimates of the mean survival time when the sample size was 500 and a Weibull distribution was used. When the sample size was 100 and the Weibull distribution was used, the Guyot et al. method was almost as accurate as the Hoyle and Henley method; however, more biases were identified in the traditional methods. When a lognormal distribution was used, the Guyot et al. method generated noticeably less bias and a more accurate uncertainty compared with the Hoyle and Henley method. Conclusions The traditional methods should not be preferred because of their remarkable overestimation. When the Weibull distribution was used for a fitted model, the Guyot et al. method was almost as accurate as the Hoyle and Henley method. However, if the lognormal distribution was used, the Guyot et al. method was less biased compared with the Hoyle and Henley method. PMID:25803659

  1. S-Shaped Canals: A Series of Cases Performed by Four Specialists around the World

    PubMed Central

    Machado, Ricardo; Chaniottis, Antonis; Vera, Jorge; Saucedo, Carlos; Vansan, Luiz Pascoal; Silva, Emmanuel João Nogueira Leal

    2014-01-01

    Recognition of anatomical variations is a real challenge for clinicians undertaking therapy regardless of the teeth that are to be treated. The extent of the curvature is one of the most important variables that could lead to instrument fracture. In clinical conditions, two curves can be present in the same root canal trajectory. This type of geometry is denoted as the “S” shape, and it is a challenging condition. This report describes a different clinical and educational scenario where four specialists around the world present different approaches for the treatment of root canals with double curvatures or S-shaped canals. Endodontic therapy is a very nuanced and challenging science and art. The clinical and teaching experience of the authors show different approaches that can be successfully employed to treat challenging teeth having roots with multiple curves. The necessity of precise knowledge of the root canal morphology and its variation is also underlined. PMID:25143838

  2. An In Vitro Comparison of Root Canal Transportation by Reciproc File With and Without Glide Path

    PubMed Central

    Nazarimoghadam, Kiumars; Daryaeian, Mohammad; Ramazani, Nahid

    2014-01-01

    Objective: The aim of ideal canal preparation is to prevent iatrogenic aberrations such as transportation. The aim of this study was to evaluate the root canal transportation by Reciproc file with and without glide path. Materials and Methods: Thirty acrylic-resin blocks with a curvature of 60° and size#10 (2% taper) were assigned into two groups (n= 15). In group 1, the glide path was performed using stainless steel k-files size#10 and 15 at working length In group 2, canals were prepared with Reciproc file system at working length. By using digital imaging software (AutoCAD 2008), the pre-instrumentation and post-instrumentation digital images were superimposed over, taking the landmarks as reference points. Then the radius of the internal and external curve of the specimens was calculated at three α, β and γ points (1mm to apex as α, 3mm to apex as β, and 5mm to apex as γ). The data were statically analyzed using the independent T-test and Mann-Whitney U test by SPSS version 16. Results: Glide path was found significant for only external curve in the apical third of the canal; that is, 5mm to apex (P=0.005). But in the other third, canal modification was not significant (P> 0.008). Conclusion: Canal transportation in the apical third of the canal seems to be significantly reduced when glide path is performed using reciprocating files. PMID:25628682

  3. The Love Canal: Beyond science?

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    When in 1978, the New York State Department of Health issued the report, ‘Love Canal—Public Health Time Bomb,’ the serious effects of chemical waste contamination in the Love Canal area became an issue of national concern. A few ‘studies’ since then have produced results in concert with those of initial reports that described ‘conditions of acute health effects’ as being linked to hazardous wastes incorporated in landfill in the Love Canal site near Niagara Falls, New York. Now that a ‘blue ribbon’ panel of experts from the medical sciences has reviewed the problems of Love Canal, however, a different view has emerged. The ‘Report of the Governors' Panel to Review Scientific Studies and the Development of Public Policy on Problems Resulting from Hazardous Wastes,’ transmitted in October of this year, identifies the following factors about the health effects at Love Canal:

  4. Superior Semicircular Canal Dehiscence (SSCD)

    MedlinePlus

    ... canal that is being activated. Analysis of the eye movements evoked by sound and pressure stimuli in patients ... to the identification of this syndrome. These evoked eye movements often align with the plane of the superior ...

  5. Looking back at Love Canal

    SciTech Connect

    Deegan, J. Jr.

    1987-05-01

    In the first part of this series (ES and T, April 1987, pp. 328-31) it was pointed out that the methods and conclusions of EPA's Love Canal Study were the subject of some controversy in the environmental community. Others defended the agency's approaches and methods. Part 2 makes no attempt to resolve the controversy; its purpose is to present the results and conclusions of the Love Canal.

  6. The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations

    SciTech Connect

    Mueller, Martin; /SLAC

    2010-12-16

    The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

  7. Response curves for phosphorus plume lengths from reactive-solute-transport simulations of onland disposal of wastewater in noncarbonate sand and gravel aquifers

    USGS Publications Warehouse

    Colman, John A.

    2005-01-01

    infiltration bed after disposal cessation. Duration of disposal before cessation was assumed to be 50 years into an infiltration bed of 20,000 square feet at the rate of 3 gallons per square foot per day. Time for the maximum extent of the phosphorus plume to develop is on the order of 100 years after disposal cessation. Simulations indicated that phosphorus transport beyond the extent of the 0.015 milligram-per-liter concentration contour was never more than 0.18 kilogram per year, an amount that would likely not alter the ecology of most surface water. Simulations of phosphorus plume lengths were summarized in a series of response curves. Simulated plume lengths ranged from 200 feet for low phosphorus-concentration effluents (0.25 milligram per liter) and thick (50 feet) unsaturated zones to 3,400 feet for high phosphorus-concentration effluents (14 milligrams per liter) discharged directly into the aquifer (unsaturated-zone thickness of 0 feet). Plume length was nearly independent of unsaturated-zone thickness at phosphorus concentrations in the wastewater that were less than 2 milligrams per liter because little or no phosphorus mineral formed at low phosphorus concentrations. For effluents of high phosphorus concentration, plume length varied from 3,400 feet for unsaturated-zone thickness of 0 to 2,550 feet for unsaturated-zone thickness of 50 feet. Model treatments of flow and equilibrium-controlled chemistry likely were more accurate than rates of kinetically controlled reactions, notably precipitation of iron-phosphate minerals; the kinetics of such reactions are less well known and thus less well defined in the model. Sensitivity analysis indicated that many chemical and physical aquifer properties, such as hydraulic gradient and model width, did not affect the simulated plume length appreciably, but duration of discharge, size of infiltration bed, amount of dispersion, and number of sorption sites on the aquifer sediments did affect plume length ap

  8. Mimamata and Love Canal: A Pollution Tale of Two Cities.

    ERIC Educational Resources Information Center

    Williams, Mary Louise

    1993-01-01

    Presents a lesson plan about case studies of the environmental disasters of Minamata, Japan and Love Canal, New York. Compares how the legal cases were handled in two constitutional democracies. Provides six handouts that include maps, role descriptions for simulations, and student readings. (CFR)

  9. Root Canal Shaping by Single-File Systems and Rotary Instruments: a Laboratory Study

    PubMed Central

    Bane, Khaly; Faye, Babacar; Sarr, Mouhamed; Niang, Seydina O; Ndiaye, Diouma; Machtou, Pierre

    2015-01-01

    Introduction: The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Methods and Materials: Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25° and 35° and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc (R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey’s test. The level of significance was set at 0.05. Results: Both single-instrument systems reduced the canal preparation time by approximately 50% (P<0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P<0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P<0.05). No case of blockage or perforation was found during shaping in any group. Conclusion: Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature. PMID:25834600

  10. Computed tomography evaluation of rotary systems on the root canal transportation and centering ability.

    PubMed

    Pagliosa, André; Sousa-Neto, Manoel Damião; Versiani, Marco Aurélio; Raucci-Neto, Walter; Silva-Sousa, Yara Teresinha Corrêa; Alfredo, Edson

    2015-01-01

    The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi) rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10), according to the biomechanical preparative system used: Hero 642 (HR), Liberator (LB), ProTaper (PT), and Twisted File (TF). The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey's tests (α = 0.05). The results demonstrated no significant difference (p > 0.05) in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR); -0.004 ± 0.044 mm (LB); -0.003 ± 0.064 mm (PT); -0.021 ± 0.064 mm (TF). The mean canal centering ability was: -0.093 ± 0.147 mm (HR); -0.001 ± 0.100 mm (LB); -0.002 ± 0.134 mm (PT); -0.033 ± 0.133 mm (TF). Also, there was no significant difference among the root segments (p > 0.05). It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape.

  11. Method for Simulating the Thickness Distribution of a Cubic Boron Nitride Film Deposited on a Curved Substrate using Ion-beam-assisted Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Valizadeh, R.; Colligon, J. S.; Kanematsu, H.; Morisato, K.

    A method for simulating the thickness distribution of cubic boron nitride (cBN) films deposited on a curved substrate using ion-beam-assisted vapor deposition (IBAD) is established and discussed. The deposition conditions are (i) boron arriving rate is 3.2 Å/s, (ii) ion current density is in the range 600-1600 μA/cm2, and (iii) gas composition fed into the ion source is 36% N2 + Ar. It was found that, due to simultaneous deposition and sputtering, the boron resputtering yield (which depends on the ion incident angle during cBN deposition) estimated from experimental data was higher than that of the boron sputtering yield of the BN films with a density of 3.482 g/cm3 calculated by the TRIM code. Using the above empirical boron resputtering yield, it is estimated that in the case of static coating, cBN films would not be formed when the incident angle is more than 40°. However, with continuous waving, the distribution of film thickness improves and the results are consistent with the experimental results. This estimation also agrees with the experimental results of discrete waving deposition within an allowable margin of error

  12. Modeling of sound transmission from ear canal to cochlea.

    PubMed

    Gan, Rong Z; Reeves, Brian P; Wang, Xuelin

    2007-12-01

    A 3-D finite element (FE) model of the human ear consisting of the external ear canal, middle ear, and cochlea is reported in this paper. The acoustic-structure-fluid coupled FE analysis was conducted on the model which included the air in the ear canal and middle ear cavity, the fluid in the cochlea, and the middle ear and cochlea structures (i.e., bones and soft tissues). The middle ear transfer function such as the movements of tympanic membrane, stapes footplate, and round window, the sound pressure gain across the middle ear, and the cochlear input impedance in response to sound stimulus applied in the ear canal were derived and compared with the published experimental measurements in human temporal bones. The frequency sensitivity of the basilar membrane motion and intracochlear pressure induced by sound pressure in the ear canal was predicted along the length of the basilar membrane from the basal turn to the apex. The satisfactory agreements between the model and experimental data in the literature indicate that the middle ear function was well simulated by the model and the simplified cochlea was able to correlate sound stimulus in the ear canal with vibration of the basilar membrane and pressure variation of the cochlear fluid. This study is the first step toward the development of a comprehensive FE model of the entire human ear for acoustic-mechanical analysis.

  13. Corinth Canal, Greece

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Isthmus of Corinth has played a very important role in the history of Greece. It is the only land bridge between the country's north (Attica) and south (Peloponnese). It is a 6 km wide tongue of land separating the Gulf of Corinth from the Saronic Sea. Populations, armies and commodities have got to move through it. In the 6th century BCE, the Greeks built the Diolkos, a 10 meter-wide stone roadway to pull ships across the Isthmus on wooden cylinders and wheeled vehicles. In 1882, a canal was started and completed 11 years later. It is 6343 meters long, 25 meters wide, and 8 meters deep.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 25.3 by 37.7 kilometers (15.7 by 23.4 miles) Location: 37.9 degrees North latitude, 23 degrees East longitude

  14. Ship canals and aquatic ecosystems

    USGS Publications Warehouse

    Aron, William I.; Smith, Stanford H.

    1971-01-01

    Through a combination of ecosystem homeostasis and the perversity of man and nature, oftentimes the significant biological changes effected by environmental modifications are not detected until long after the initial change has taken place. The immediate impact, which may range from the spectacular to the undetectable, is a deceptive measure of the long-term and often more important changes in the ecosystem. Two major engineering achievements illustrate this premise: (i) construction of the Erie Canal, which provided access from the Atlantic Ocean to the Great Lakes, and the Welland Canal, which bypasses the block between Lakes Ontario and Erie created by Niagara Falls (Fig. 1), and (ii) construction of the Suez Canal between the Red Sea and the Mediterranean Sea.

  15. Wavelength dependence of photon-induced photoacoustic streaming technique for root canal irrigation

    NASA Astrophysics Data System (ADS)

    Lukač, Nejc; Zadravec, Jure; Gregorčič, Peter; Lukač, Matjaž; Jezeršek, Matija

    2016-07-01

    Laser-enhanced irrigation of complex root canals appears to be a very promising technique to improve the outcome of root canal treatment. This applies, in particular, if the technique can be effective at very low laser energies in irrigating not only the main canal but also the small lateral canals. This is important in order to avoid potential undesirable effects at higher laser energies such as temperature increase, dentin ablation, or extrusion of irrigating solution beyond the apical foramen. An improved understanding of the role of laser parameters, such as laser wavelength and pulse duration, in irrigation of lateral canals is therefore desired in order to optimize treatment efficacy. The influence of laser wavelength and pulse duration on cavitation phenomena was studied using shadow photography and a method of measuring fluid flow in lateral canals based on tracking of movements of small air bubbles naturally forming in liquid as a result of laser agitation. A simulated model of a root canal including a narrow lateral canal designed to represent typical root canal morphology was used for the water flow measurements. The following three laser wavelengths with relatively high absorption in water were studied: Er:YAG (2.94 μm), Er,Cr:YSGG (2.73 μm), and Nd:YAP (1.34 μm). Among the three wavelengths studied, the Er:YAG laser wavelength was found to be the most effective in formation of cavitation bubbles and in generating fluid motions within narrow lateral canals. A comparison between the shadow photography and fluid motion data indicates that it is the bubble's radius and not the bubble's volume that predominantly influences the fluid motion within lateral canals. Based on the results of our study, it appears that effective minimally invasive laser-assisted irrigation can be performed with low Er:YAG laser pulse energies below 10 mJ.

  16. The influence of canal curvature on the mechanical efficacy of root canal irrigation in vitro using real-time imaging of bioluminescent bacteria.

    PubMed

    Nguy, Donald; Sedgley, Christine

    2006-11-01

    There are no quantitative data on the mechanical efficacy of irrigation in the removal of bacteria from curved canals. This study quantitatively analyzed the effects of root canal curvature and preparation size on the mechanical efficacy of irrigation using 33 mandibular single-rooted bicuspids allocated to groups according to root canal curvatures, group 1 (straight) 4 to 8 degrees, group 2 (intermediate curvature) 15 to 19 degrees, and group 3 (greatest curvature) 24 to 28 degrees. Teeth were sequentially instrumented to sizes 27/.04, 36/.04, and 46/.04 using a crown-down technique. Suspensions of the bioluminescent reporter strain Pseudomonas fluorescens 5RL (1.5 x 10(6) cells) were inoculated into canals of sterilized teeth after each sequential instrumentation. Canals were irrigated with 6 ml of irrigant delivered 1 mm from working length using a 30-gauge needle. Remaining bacteria were quantified using real-time bioluminescent imaging. Irrigation was significantly less effective in 24 to 28 degrees curvature canals prepared to size 27/.04 compared to 46/.04 (p < 0.007, repeated-measures ANOVA).

  17. Sonic instruments in root canal therapy.

    PubMed

    Waplington, M; Lumley, P J; Walmsley, A D

    1995-10-01

    Although hand instrumentation is considered the most acceptable method of preparing root canals, sonic instruments may be useful additions to the endodontic armamentarium. Sonic instrumentation may be incorporated as an adjunct to traditional techniques for shaping the root canal. The use of such instruments may assist the practitioner during root canal treatment in general practice.

  18. [Anatomical variations in the hypoglossal canal].

    PubMed

    De Francisco, M; Lemos, J L; Liberti, E A; Adamo, J; Jácomo, A L; Matson, E

    1990-01-01

    In this paper, 492 human dried skulls grouped according to sex and race (White and no White) were examined and the presence of a double hypoglossal canal was observed in 97 skulls. The statistical analysis allowed us to conclude that no significative difference exists in race X canal type; sex X canal type; race X side and sex X side interations.

  19. Erie Canal Technology: Stump Pullers

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2013-10-01

    Many years ago I saw a picture of a huge set of wheels that was used to remove tree stumps during the construction of the Erie Canal (1817-1825) and was intrigued by its use of leverage, mechanical advantage, and torque. Figure 1 is a scale model of the device based on my memory of the (lost) picture and published accounts.

  20. Erie Canal Technology: Stump Pullers

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2013-01-01

    Many years ago I saw a picture of a huge set of wheels that was used to remove tree stumps during the construction of the Erie Canal (1817-1825) and was intrigued by its use of leverage, mechanical advantage, and torque. Figure 1 is a scale model of the device based on my memory of the (lost) picture and published accounts.

  1. [Endodontic microbiology: antimicrobial canal medications].

    PubMed

    Seltzer, S; Farber, P A

    1989-06-01

    Medicaments used for reducing or eliminating microorganisms from infected root canals include: irrigating solutions, such as sodium hypochlorite, urea peroxide and hydrogen peroxide, chloramine, iodine-potassium-iodide solution, and chlorhexidine solution. In addition, various intracanal drugs, such as calcium hydroxide and antibiotics, are in use. The characteristics of these drugs are discussed.

  2. Dynamic intratubular biomineralization following root canal obturation with pozzolan‐based mineral trioxide aggregate sealer cement

    PubMed Central

    Yoo, Yeon‐Jee; Baek, Seung‐Ho; Kum, Kee‐Yeon; Shon, Won‐Jun; Woo, Kyung‐Mi

    2015-01-01

    Summary The application of mineral trioxide aggregates (MTA) cement during the root canal obturation is gaining concern due to its bioactive characteristic to form an apatite in dentinal tubules. In this regard, this study was to assess the biomineralization of dentinal tubules following root canal obturation by using pozzolan‐based (Pz‐) MTA sealer cement (EndoSeal MTA, Maruchi). Sixty curved roots (mesiobuccal, distobuccal) from human maxillary molars were instrumented and prepared for root canal obturation. The canals were obturated with gutta‐percha (GP) and Pz‐MTA sealer by using continuous wave of condensation technique. Canals obturated solely with ProRoot MTA (Dentsply Tulsa Dental) or Pz‐MTA sealer were used for comparison. In order to evaluate the biomineralization ability under different conditions, the PBS pretreatment before the root canal obturation was performed in each additional samples. At dentin‐material interfaces, the extension of intratubular biomineralization was analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy. When the root canal was obturated with GP and Pz‐MTA sealer, enhanced biomineralization of the dentinal tubules beyond the penetrated sealer tag was confirmed under the SEM observation (p < 0.05). Mineralized apatite structures (calcium/phosphorous ratio, 1.45–1.89) connecting its way through the dentinal tubules were detected at 350–400 μm from the tubule orifice, and the pre‐crystallization seeds were also observed along the intra‐ and/or inter‐tubular collagen fiber. Intratubular biomineralization depth was significantly enhanced in all PBS pretreated canals (p < 0.05). Pz‐MTA cement can be used as a promising bioactive root canal sealer to enhance biomineralization of dentinal tubules under controlled environment. SCANNING 38:50–56, 2016. © 2015 The Authors. Scanning Published by Wiley Periodicals, Inc. PMID:26179659

  3. Full-particle 2-D Simulations of the Ion Foreshock associated to a Supercritical Quasi-perpendicular Curved Collisionless Shock : Origin of Backstreaming Energetic Particles

    NASA Astrophysics Data System (ADS)

    Savoini, P.; Lembege, B.

    2014-12-01

    The ion foreshock located upstream of the Earth's bow shock is populated with ions reflected back by the shock front. In-situ spacecraft measurements have clearly established the existence of two distinct populations in the upstream of the quasi-perpendicular shock region (i.e. for 45o ≤ ΘBn≤ 90o, where ΘBn is the angle between the shock normal and the upstream magnetostatic field): (i) field-aligned ion beams (or 'FAB') characterized by a gyrotropic distribution, and (ii) gyro-phase bunched ions (or 'GPB') characterized by a NON gyrotropic distribution, which exhibits a non-vanishing perpendicular bulk velocity. The use of 2D PIC simulations where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described, has evidenced that the shock front itself can be the possible source of these two characteristic populations. A recent analysis has evidenced that both populations can be discriminated in terms of interaction time (Δtinter) with the shock front. 'GPB' and 'FAB' populations are characterized by a short (Δtinter ~ 1 τci) and much larger (Δtinter ≥ 2 τci) interaction time respectively, where τci is the ion upstream gyroperiod. In addition, present statistical results evidence that: (i) backstreaming ions are splitted into 'FAB' and 'GPB' populations depending on their injection angle when hitting the shock front (defined between the local normal to the shock front and the gyration velocity vector). (ii) As a consequence, ion trajectories strongly differ between the 'FAB' and 'GPB' populations at the shock front. In particular, 'FAB' ions suffer multi-bounces along the curved front whereas 'GPB' ions make only one bounce. Such differences may explain why the 'FAB' population loses their gyro-phase coherency and become gyrotropic which is not the case for the 'GPB'. Then, the differences observed between 'FAB' and 'GPB' populations do not involve some distinct reflection processes as often claimed in the

  4. Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples

    PubMed Central

    Jacobs, Reinhilde; Lambrechts, Paul; Brizuela, Claudia; Cabrera, Carolina; Concha, Guillermo; Pedemonte, María Eugenia

    2015-01-01

    Purpose This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. Materials and Methods We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. Results The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. Conclusion In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning. PMID:26125004

  5. 12. CONCRETE LINING ON A CURVING SEGMENT OF THE LATERAL ...

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

    12. CONCRETE LINING ON A CURVING SEGMENT OF THE LATERAL NEAR THE NORTHEAST END OF LAKE LADORA (SECTION 2). - Highline Canal, Sand Creek Lateral, Beginning at intersection of Peoria Street & Highline Canal in Arapahoe County (City of Aurora), Sand Creek lateral Extends 15 miles Northerly through Araphoe County, City & County of Denver, & Adams County to its end point, approximately 1/4 mile Southest of intersectioin of D Street & Ninth Avenue in Adams County (Rocky Mountain Arsenal, Commerce City Vicinity), Commerce City, Adams County, CO

  6. Management of Six Root Canals in Mandibular First Molar

    PubMed Central

    Gomes, Fabio de Almeida; Sousa, Bruno Carvalho

    2015-01-01

    Success in root canal treatment is achieved after thorough cleaning, shaping, and obturation of the root canal system. This clinical case describes conventional root canal treatment of an unusual mandibular first molar with six root canals. The prognosis for endodontic treatment in teeth with abnormal morphology is unfavorable if the clinician fails to recognize extra root canals. PMID:25685156

  7. Sediment loads in canals 18, 23, and 24 in southeastern Florida

    USGS Publications Warehouse

    Pitt, William A. J.

    1971-01-01

    Suspended-sediment concentrations and suspended-sediment discharges were determined in selected canals in St. Lucie, Martin, and Palm Beach Counties, in southeastern Florida. Sediment rating curves were developed to relate water discharge to sediment concentration at the three sites sampled. An evaluation of the concentration and sediment loads shows that larger amounts of suspended sediment were being carried into the St. Lucie River estuary than were being carried into the Loxahatchee River estuary. Peat and muck soils in areas drained for agricultural planting and citrus cultivation are readily carried by runoff water into major canals that traverse the region.

  8. The primate semicircular canal system and locomotion

    PubMed Central

    Spoor, Fred; Garland, Theodore; Krovitz, Gail; Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan

    2007-01-01

    The semicircular canal system of vertebrates helps coordinate body movements, including stabilization of gaze during locomotion. Quantitative phylogenetically informed analysis of the radius of curvature of the three semicircular canals in 91 extant and recently extinct primate species and 119 other mammalian taxa provide support for the hypothesis that canal size varies in relation to the jerkiness of head motion during locomotion. Primate and other mammalian species studied here that are agile and have fast, jerky locomotion have significantly larger canals relative to body mass than those that move more cautiously. PMID:17576932

  9. Love Canal: environmental and toxicological studies

    SciTech Connect

    Kim, C.S.

    1981-01-01

    The New York State Department of Health has been involved at the Love Canal since 1978. The State has carried out numerous environmental and toxicological studies. The major purposes for these studies were to define how Love Canal contaminants might be escaping into the environment at large, what paths contaminant migration might take, and what toxicological effects Love Canal chemicals might have individually and together. Although underground contaminant migration was hypothesized along swales and underground utility bedding, these mechanisms have been proven not to be operative except for some migration along the utility bedding under Frontier Avenue. In general no underground migration has occurred outside the confines of the three city blocks that contain the Love Canal referred to as the ''first ring''. Studies have been confused by apparent burial of waste materials in areas proximate but not directly connected to the Love Canal. Migration of Love Canal leachate has occurred through storm sewers. Love Canal contaminants have reached creeks to the north and the Niagara River to the south through storm sewer transport. In spite of finding 2, 3, 7, 8 tetrachlorodibenzoparadioxin (TCDD), toxicological studies in situ and through exposure to volatile components in Love Canal soils do not indicate unusual toxicity. Animal studies continue in an attempt to determine the teratogenic and fetotoxic potential of Love Canal chemicals under different routes of exposure.

  10. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal...

  11. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal...

  12. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal...

  13. 10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, ...

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

    10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, CLAD COUNTER WEIGHT, WATER SPAN RAISED OUT OF VIEW - Cape Cod Canal Lift Bridge, Spanning Cape Cod Canal, Buzzards Bay, Barnstable County, MA

  14. 3. August, 1971. VIEW ALONG CANAL SHOWING BORDER PATH AND ...

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

    3. August, 1971. VIEW ALONG CANAL SHOWING BORDER PATH AND BRIDGE FOR INSPECTION - ABOUT ONE MILE FROM CANAL HEAD. - Hurricane Irrigation Canal, State Route 15 Vicinity, Hurricane, Washington County, UT

  15. 5. Division Gates of the Consolidated Canal, looking northeast. The ...

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

    5. Division Gates of the Consolidated Canal, looking northeast. The Tempe Canal heads here (left). Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  16. 15. VIEW OF GAGE IRRIGATION CANAL NEAR HILLTOP DRIVE AND ...

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

    15. VIEW OF GAGE IRRIGATION CANAL NEAR HILLTOP DRIVE AND BARTON ROAD, SHOWING END OF SIPHON. CANAL FOLLOWS CONTOUR OF HILL UNDER DIRT ROAD - Gage Irrigation Canal, Running from Santa Ana River to Arlington Heights, Riverside, Riverside County, CA

  17. 11. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW ...

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

    11. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW LOOKING WEST FROM MAIN CANAL - San Carlos Irrigation Project, Marin Canal, Amhurst-Hayden Dam to Picacho Reservoir, Coolidge, Pinal County, AZ

  18. Dundee Canal Industrial Historic District, Beginning at George Street in ...

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

    Dundee Canal Industrial Historic District, Beginning at George Street in Passaic & extending north along Dundee Canal approximately 1.2 miles to Canal headgates opposite East Clifton Avenue in Clifton, Passaic, Passaic County, NJ

  19. Evaluating Pending Decisions in a Large Introductory Course: The Panama Canal Treaties.

    ERIC Educational Resources Information Center

    Gilman, Stuart C.; And Others

    1979-01-01

    Describes a simulation for an introductory American government course. It was based on the Panama Canal treaties ratification process, a decision pending in the Senate which was due to culminate before the end of the course. By keying the simulation to a real event, participants obtained real-world feedback on how closely their roles approximated…

  20. Root Canal Treatment of a Maxillary Second Premolar with Two Palatal Root Canals: A Case Report

    PubMed Central

    Golmohammadi, Maryam; Jafarzadeh, Hamid

    2016-01-01

    Accurate diagnosis of the root canal morphology and anatomy is essential for thorough shaping and cleaning of the entire root canal system and consequent successful treatment. This report describes a case of maxillary second premolar with two roots and three root canals (two mesial and distal palatal canals). The case report underlines the importance of complete knowledge about root canal morphology and possible variations, coupled with clinical and radiographic examination in order to increase the ability of clinicians to treat difficult cases. PMID:27471538

  1. A mathematical model of epiphyseal development: hypothesis on the cartilage canals growth.

    PubMed

    Garzon-Alvarado, Diego Alexander; Peinado Cortes, Liliana Mabel; Cardenas Sandoval, Rosy Paola

    2010-12-01

    The role of cartilage canals is to transport nutrients and biological factors that cause the appearance of the secondary ossification centre (SOC). The SOC appears in the centre of the epiphysis of long bones. The canal development is a complex interaction between mechanical and biological factors that guide its expansion into the centre of the epiphysis. This article introduces the 'Hypothesis on the growth of cartilage canals'. Here, we have considered that the development of these canals is an essential event for the appearance of SOC. Moreover, it is also considered to be important for the transport of molecular factors (RUNX2 and MMP9) at the ends of such canals. Once the canals are merged in the centre of the epiphysis, these factors are released causing hypertrophy of adjacent cells. This RUNX2 and MMP9 release occurs due to the action of mechanical loads that supports the epiphysis. In order to test this hypothesis, we use a hybrid approach using the finite element method to simulate the mechanical stresses present in the epiphysis and the cellular automata to simulate the expansion of the canals and the hypertrophy factors pathway. By using this hybrid approach, we have obtained as a result the spatial-temporal patterns for the growth of cartilage canals and hypertrophy factors within the epiphysis. The model is in qualitative agreement with experimental results previously reported by other authors. Thus, we conclude that this model may be used as a methodological basis to present a complete mathematical model of the processes involved in epiphyseal development.

  2. 33 CFR 117.445 - Franklin Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Franklin Canal. 117.445 Section 117.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.445 Franklin Canal. The draw of the Chatsworth Bridge, mile 4.8 at Franklin, shall...

  3. 33 CFR 117.285 - Grand Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing Island bridge, mile 0.7, shall open on...

  4. 33 CFR 117.787 - Gowanus Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Gowanus Canal. 117.787 Section 117.787 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.787 Gowanus Canal. The draws of the Ninth Street Bridge, mile 1.4, the Third...

  5. 33 CFR 117.453 - Houma Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Houma Canal. 117.453 Section 117.453 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.453 Houma Canal. The draw of the S3197 bridge, mile 1.7 at Houma, shall open on signal...

  6. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  7. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  8. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  9. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  10. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  11. [Upper lateral incisor with 2 canals].

    PubMed

    Fabra Campos, H

    1991-01-01

    Clinical case summary of the patient with an upper lateral incisor with two root canals. The suspicion that there might be an anatomic anomaly in the root that includes a complex root canal system was made when an advanced radicular groove was detected in the lingual surface or an excessively enlarged cingulum.

  12. 33 CFR 117.444 - Falgout Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Falgout Canal. 117.444 Section 117.444 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.444 Falgout Canal. The draw of the...

  13. Benign lesions of the external auditory canal.

    PubMed

    Tran, L P; Grundfast, K M; Selesnick, S H

    1996-10-01

    Benign mass lesions of the external auditory canal, such as exostoses and osteomas, are common findings on physical examination but most often do not require treatment. The differential diagnosis of lesions in the external auditory canal, however, should not be limited to those benign processes discussed here, but should also include infectious, dermatologic, congenital, and malignant processes.

  14. Metoptic canal, duplication of the optic canal and Warwick’s foramen in human orbits.

    PubMed

    Bertelli, Eugenio

    2014-01-01

    The region of the optic strut is sometimes traversed by some minor canals whose incidence and general characteristics have never been studied. As such canals could be the route for vessels that could interfere in the surgery of the orbital apex, we undertook a detailed anatomical study on a vast collection of dry skulls. The examination of 943 dry adult skulls and 360 foetal skulls was carried out to precise the anatomy of canals in the optic strut area, their development and relationships with the optic canal. A canal traversing the optic strut was present in 8.54 % of the orbits. Based on diameter, position within the optic strut, and thickness of the bony plate separating it from the optic canal or from the superior orbital fissure, the canals piercing the optic strut were classified into four types, which include the well-known duplication of the optic canal, different aspects of the metoptic canal and a type of canal that to our knowledge has never been reported. Warwick’s foramen was found in 0.74 % of orbits. The area of the optic strut is the frequent site of canals joining the orbit with the middle cranial fossa. Some of them can host the ophthalmic artery; others could be run by minor vessels which, however, could be the source of annoying bleedings in surgical procedures.

  15. Improvement of Water Quality at Dongbin Harbor with Construction of an Inland Canal, Korea

    PubMed Central

    Cho, Yong-Sik

    2014-01-01

    The behaviors of the water body of Dongbin Harbor located at Pohang City, Gyongpook Province, in Korea were numerically simulated in this study. A canal was planned to connect the harbor and the Hyeongsan River to improve water quality inside the harbor. The current system was first simulated by using a commercial program RMA2, with respect to both tidal currents and river flow. The progress inside the harbor from a supply of fresh water from the Hyeongsan River was then predicted by using RMA4. Both the present and future conditions (before and after construction of an inland canal) were taken into consideration in numerical simulations. It is concluded that the water quality inside the harbor can be improved considerably after construction of the canal. PMID:25003149

  16. Tissue engineering in endodontics: root canal revascularization.

    PubMed

    Palit Madhu Chanda; Hegde, K Sundeep; Bhat, Sham S; Sargod, Sharan S; Mantha, Somasundar; Chattopadhyay, Sayan

    2014-01-01

    Root canal revascularization attempts to make necrotic tooth alive by the use of certain simple clinical protocols. Earlier apexification was the treatment of choice for treating and preserving immature permanent teeth that have lost pulp vitality. This procedure promoted the formation of apical barrier to seal the root canal of immature teeth and nonvital filling materials contained within root canal space. However with the success of root canal revascularization to regenerate the pulp dentin complex of necrotic immature tooth has made us to rethink if apexification is at the beginning of its end. The objective of this review is to discuss the new concepts of tissue engineering in endodontics and the clinical steps of root canal revascularization.

  17. Looking back at Love Canal

    SciTech Connect

    Deegan, J. Jr.

    1987-04-01

    The comprehensive environmental study which describes the results of a monitoring program conducted by EPA at Love Canal is evaluated by EPA's former study director. Attention is focused on the episode's history and the agency's study methods. The aim of the program was to constitute a study team, design a monitoring study, reprogram and reallocate the financial resources needed to conduct the study, and identify and employ contractors who would collect and analyze environmental samples. The agency was directed to ensure the quality of the data acquired from various environmental media and analyzed by numerous laboratories; to integrate, interpret, and report the data; and to assess, from an environmental perspective, the habitability of the area.

  18. Cochlear microphonic broad tuning curves

    NASA Astrophysics Data System (ADS)

    Ayat, Mohammad; Teal, Paul D.; Searchfield, Grant D.; Razali, Najwani

    2015-12-01

    It is known that the cochlear microphonic voltage exhibits much broader tuning than does the basilar membrane motion. The most commonly used explanation for this is that when an electrode is inserted at a particular point inside the scala media, the microphonic potentials of neighbouring hair cells have different phases, leading to cancelation at the electrodes location. In situ recording of functioning outer hair cells (OHCs) for investigating this hypothesis is exceptionally difficult. Therefore, to investigate the discrepancy between the tuning curves of the basilar membrane and those of the cochlear microphonic, and the effect of phase cancellation of adjacent hair cells on the broadness of the cochlear microphonic tuning curves, we use an electromechanical model of the cochlea to devise an experiment. We explore the effect of adjacent hair cells (i.e., longitudinal phase cancellation) on the broadness of the cochlear microphonic tuning curves in different locations. The results of the experiment indicate that active longitudinal coupling (i.e., coupling with active adjacent outer hair cells) only slightly changes the broadness of the CM tuning curves. The results also demonstrate that there is a π phase difference between the potentials produced by the hair bundle and the soma near the place associated with the characteristic frequency based on place-frequency maps (i.e., the best place). We suggest that the transversal phase cancellation (caused by the phase difference between the hair bundle and the soma) plays a far more important role than longitudinal phase cancellation in the broadness of the cochlear microphonic tuning curves. Moreover, by increasing the modelled longitudinal resistance resulting the cochlear microphonic curves exhibiting sharper tuning. The results of the simulations suggest that the passive network of the organ of Corti determines the phase difference between the hair bundle and soma, and hence determines the sharpness of the

  19. How to bond to root canal dentin

    NASA Astrophysics Data System (ADS)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  20. Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model

    PubMed Central

    Bauer, Brad A.; Patel, Sandeep

    2009-01-01

    We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of Tc=623 K, ρc=0.351 g∕cm3, and Pc=250.9 atm, which are in good agreement with experimental values of Tc=647.1 K, ρc=0.322 g∕cm3, and Pc=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (Tc=631 K and ρc=0.308 g∕cm3). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300–450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase

  1. Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model

    NASA Astrophysics Data System (ADS)

    Bauer, Brad A.; Patel, Sandeep

    2009-08-01

    We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of Tc=623 K, ρc=0.351 g/cm3, and Pc=250.9 atm, which are in good agreement with experimental values of Tc=647.1 K, ρc=0.322 g/cm3, and Pc=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (Tc=631 K and ρc=0.308 g/cm3). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300-450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase-dependent polarizability with

  2. Are driving and overtaking on right curves more dangerous than on left curves?

    PubMed

    Othman, Sarbaz; Thomson, Robert; Lannér, Gunnar

    2010-01-01

    It is well known that crashes on horizontal curves are a cause for concern in all countries due to the frequency and severity of crashes at curves compared to road tangents. A recent study of crashes in western Sweden reported a higher rate of crashes in right curves than left curves. To further understand this result, this paper reports the results of novel analyses of the responses of vehicles and drivers during negotiating and overtaking maneuvers on curves for right hand traffic. The overall objectives of the study were to find road parameters for curves that affect vehicle dynamic responses, to analyze these responses during overtaking maneuvers on curves, and to link the results with driver behavior for different curve directions. The studied road features were speed, super-elevation, radius and friction including their interactions, while the analyzed vehicle dynamic factors were lateral acceleration and yaw angular velocity. A simulation program, PC-Crash, has been used to simulate road parameters and vehicle response interaction in curves. Overtaking maneuvers have been simulated for all road feature combinations in a total of 108 runs. Analysis of variances (ANOVA) was performed, using two sided randomized block design, to find differences in vehicle responses for the curve parameters. To study driver response, a field test using an instrumented vehicle and 32 participants was reviewed as it contained longitudinal speed and acceleration data for analysis. The simulation results showed that road features affect overtaking performance in right and left curves differently. Overtaking on right curves was sensitive to radius and the interaction of radius with road condition; while overtaking on left curves was more sensitive to super-elevation. Comparisons of lateral acceleration and yaw angular velocity during these maneuvers showed different vehicle response configurations depending on curve direction and maneuver path. The field test experiments also showed

  3. 158. Photocopy of transit book (taken from Twin Falls Canal ...

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

    158. Photocopy of transit book (taken from Twin Falls Canal Company Transit Book #404T, Page 3, #46, Division One). START OF MAIN CANAL SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  4. 154. Photocopy of transit book (taken from Twin Falls Canal ...

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

    154. Photocopy of transit book (taken from Twin Falls Canal Company Surveyor's Transit Book #405T, Page 2, #46 Division One). STATEMENT OF SIGHT-SETTING FOR 1903 SURVEY TO ALIGN SOUTH SIDE CANAL, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  5. 180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, ...

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

    180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, Photographer, date unknown. BLASTING TWIN FALLS CANAL, TWIN FALLS COUNTY; BLASTING COTTONWOOD AREA TO REPLACE FLUME BY RUNNING HIGH LINE THROUGH SOLID ROCK. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  6. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  7. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  8. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  9. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  10. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  11. Seepage investigations of Noyes Canal, Menard County, Texas

    USGS Publications Warehouse

    Yost, Ivan Dale

    1953-01-01

    At the request of the U.S. Department of Agriculture, Soil Conservation Service, and the Menard Irrigation Company, a seepage investigation was made on Noyes Canal (Menard Irrigation Company Canal) in Menard County, Texas, from the headgates of the canal to where the canal empties back into the San Saba River.

  12. 3. Dundee Canal looking northwest from north of Dundee Textile ...

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

    3. Dundee Canal looking northwest from north of Dundee Textile Company Mill - Dundee Canal Industrial Historic District, Beginning at George Street in Passaic & extending north along Dundee Canal approximately 1.2 miles to Canal headgates opposite East Clifton Avenue in Clifton, Passaic, Passaic County, NJ

  13. Growth of Intracranial Aneurysms Arised from Curved Vessels under the Influence of Elevated Wall Shear Stress ─ A Computer Simulation Study

    NASA Astrophysics Data System (ADS)

    Feng, Yixiang; Wada, Shigeo; Tsubota, Ken-Ichi; Yamaguchi, Takami

    Recent studies have suggested that long standing elevated wall shear stress might degenerate the arterial wall and be involved in the pathogenesis of intracranial aneurysm formation and development. The present study focuses on the interplay between the hemodynamic stresses, arterial wall degeneration and deformation. By constructing a computational model and examining the hypotheses that govern the rules to grow an intracranial aneurysm, we simulate the formation and development of intracranial aneurysms. The high wall shear stress is found to propagate towards the proximal and distal end of the formed aneurysm, which becomes the key factor for the expansion of wall degeneration and aneurysm progression. The development of aneurysm is influenced by the wall shear stress threshold, the Reynolds number and the rate of wall degeneration. Our preliminary results indicate that computer simulation can be used in the study of aneurysm mechanics and yields new insight into the mechanism of aneurysm pathophysiology.

  14. Remote sensing used for power curves

    NASA Astrophysics Data System (ADS)

    Wagner, R.; Jørgensen, H. E.; Paulsen, U. S.; Larsen, T. J.; Antoniou, I.; Thesbjerg, L.

    2008-05-01

    : Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviation in the power curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. The comparison of the power curves obtained with the three instruments to the traditional power curve, obtained using a cup anemometer measurement, confirms the results obtained from the simulations. Using LiDAR profiles reduces the error in power curve measurement, when these are used as relative instrument together with a cup anemometer. Results from the SoDAR do not show such promising results, probably because of noisy measurements resulting in distorted profiles.

  15. 7. View north at back (canal side) of culvert inlet, ...

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

    7. View north at back (canal side) of culvert inlet, with canal bank completely removed. Background to foreground: back of inlet headwall with tops of high inlet barrels exposed; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall at site of former canal edge of canal bank; dewatered canal bed and plank sheathing on top of culvert barrels beneath canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

  16. 8. VIEW SHOWING THE DEMOSSING OF GRAND CANAL LOCATION UNKNOWN. ...

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

    8. VIEW SHOWING THE DEMOSSING OF GRAND CANAL LOCATION UNKNOWN. AT TEAM OF HORSES ON OPPOSITE BANKS OF THE CANAL DRAG A CHAIN BETWEEN THEM ALONG THE BOTTOM OF THE CANAL, WHICH PULLS THE MOSS AND WEEDS LOOSE. THE PLANS THEN FLOAT DOWN THE CANAL AND ARE CAUGHT IN A SCREEN AND REMOVED. Photographer unknown, 1923 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  17. CT appearances of external ear canal cholesteatoma.

    PubMed

    Malcolm, P N; Francis, I S; Wareing, M J; Cox, T C

    1997-09-01

    External ear canal cholesteatoma (EECC) is rare in ear, nose and throat (ENT) practice. Two cases, one bilateral, are described. Computed tomography demonstrates the extent of bony involvement. Erosion of the external canal should not be overlooked when reviewing CT of the petrous bone in cases of discharge from the ear. EECC may necessitate surgery and delay in the diagnosis of EECC can result in progressive bony destruction.

  18. Mechanics of the Panama Canal slides

    USGS Publications Warehouse

    Becker, George F.

    1917-01-01

    Dr. Becker visited the Canal Zone in 1913 as a geologist of the United States Geological Survey and since that time has given the problem the benefit of his study. His appointment as a member of the committee of the National Academy of Sciences has made it appropriate for his conclusions, based upon his personal observations and already reported in part to the Canal Commission, to be stated for the benefit of his associates and other American scientists and engineers.

  19. Disinfection of Contaminated Canals by Different Laser Wavelengths, while Performing Root Canal Therapy.

    PubMed

    Asnaashari, Mohammad; Safavi, Nassimeh

    2013-01-01

    Removal of smear layer and disinfection of canals are important objectives of teeth root canal cleaning. In order to achieve this purpose, rinsing substances, intra canal drugs as well as ultrasound are used. Today, use of laser to remove smear layer and to disinfect root canals has increasingly attracted the attentions. Till now different lasers such as CO2, Nd:YAG, Er:YAG, Er,Cr:YSGG have been used for debris and smear removal from the canals. Numerous studies have shown that Er:YAG is the most appropriate laser for intra canal debris and smear removal. In addition different laser wavelengths have been used directly or as an adjunctive to disinfect canals. Laser light can penetrate areas of canals where irrigating and disinfecting solutions cannot reach, like secondary canals and deep dentinal tubules and also can eliminate microorganisms. Different studies have confirmed the penetration of Nd:YAG laser in deep dentin and reduction of microorganisms penetration. But studies on comparison of antibacterial effects of Nd:YAG laser with sodium hypochlorite showed effectiveness of both, with a better effect for sodium hypochlorite. Studies performed in relation with anti-microbial effects of Diode laser with various parameters show that this laser can be effective in reducing intra canal bacterial count and penetration in the depth of 500 microns in dentin. In studies performed on Diode laser in combination with canal irrigating solutions such as sodium hypochlorite and oxygenated water better results were obtained. Although studies on disinfection by the Erbium laser family show that use of this laser alone can be effective in disinfecting canals, studies evaluating the disinfecting effects of this laser and different concentrations of sodium hypochlorite show that the latter alone is more effective in disinfecting canals. And better results were obtained when Erbium laser was used in combination with sodium hypochlorite irrigating solution in canals. Results of the

  20. Origin of the Ion Foreshock in a Quasi-perpendicular Curved Collisionless Shock: Particles Trajectory Analysis in 2D PIC Simulations

    NASA Astrophysics Data System (ADS)

    Savoini, P.; Lembege, B.

    2015-12-01

    The ion foreshock located upstream of the Earth's shock wave is populated with ions having interacted with the shock, and then, reflected back with an high energy gain. Spacecrafts have clearly established the existence of two distinct populations in the quasi-perpendicular shock region (i.e. for 45° ≤ ΘBn ≤ 90°, where ΘBn is the angle between the shock normal and the upstream magnetic field) : (i) field-aligned ion beams or « FAB » characterized by a gyrotropic distribution, and (ii) gyro-phase bunched ions or « GPB » characterized by a NON gyrotropic distribution. One of the important unresolved problem is the exact origin of the particles contributing to these two populations. To our knowledge, it was the first time that full-particle simulations have been performed including self-consistently the shock front curvature and nonstationarity, and the time-of-flight effects. Our analysis evidences that these two backstreaming populations may be reflected by the front itself and can be differentiated both in terms of interaction time and trajectory within the shock front. In particular, simulations evidence that "GPB" population is characterized by a short interaction time (ΔTinter = 1 to 2 τci) while the "FAB" population corresponds to a much larger time range (from 1 τci to 10 τci), where tci is the upstream ion gyroperiod. Present individual ion trajectories evidence that "FAB" population shows a strong perpendicular drift at the shock front (i.e. strong dependence of the pitch angle to the perpendicular velocity) whereas the "GPB" population shows no perpendicular drift (i.e. its pitch angle is mainly driven by the parallel velocity). Such differences explain why the "FAB" population loses their gyro-phase coherency and become gyrotropic which is not the case for the "GPB". This important result was not expected and greatly simplifies the question of their origin.

  1. The fluid mechanics of root canal irrigation.

    PubMed

    Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

    2010-12-01

    Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid

  2. Optimizing Canal Structure Operation Using Meta-heuristic Algorithms in the Treasure Valley, Idaho

    NASA Astrophysics Data System (ADS)

    Hernandez, J.; Ha, W.; Campbell, A.

    2012-12-01

    The computer program that was proven to produce optimal operational solutions for open-channel irrigation conveyance and distribution networks for synthetic data in previous research was tested for real world data. Data gathered from databases and the field by the Boise Project, Idaho, provided input to the hydraulic model for the physical characteristics of the conveyance system. We selected three reaches of the Deer Flat Low Line in the Treasure Valley for optimizing actual gate operations. The total of 59.1 km canal with a maximum capacity of 34 m3/s irrigates mainly corn, wheat, sugar-beet and potato crops. The computer model uses an accuracy-based learning classifier system (XCS) with an embedded genetic algorithm to produce optimal rules for gate structure operation in irrigation canals. Rules are generated through the exploration and exploitation of genetic algorithm population, with the support of RootCanal, an unsteady-state hydraulic simulation model. The objective function was set for satisfying variable demand along three reaches while minimizing water level deviations from target. All canal gate structures operate simultaneously while maintaining water depth near target values during variable-demand periods, with a hydraulically stabilized system. It is noteworthy to mention that this very simple 3-reach problem, requires the computer performing several thousand simulations during continuous days for finding plausible solutions. The model is currently simulating the Deer Flat Low Line Canal in Caldwell, Idaho with promising results. The population evolution is measured by a fitness parameter, which shows that canal structure operations generated by the model are improving towards plausible solutions. This research is one step forward for optimizing the way we use and manage water resources. Relying on management practices of the past will no longer work in a world that is impacted by global climate variability.

  3. Application of pharmacokinetic/pharmacodynamic modelling and simulation for the prediction of target attainment of ceftobiprole against meticillin-resistant Staphylococcus aureus using minimum inhibitory concentration and time-kill curve based approaches.

    PubMed

    Barbour, April M; Schmidt, Stephan; Zhuang, Luning; Rand, Kenneth; Derendorf, Hartmut

    2014-01-01

    The purpose of this report was to compare two different methods for dose optimisation of antimicrobials. The probability of target attainment (PTA) was calculated using Monte Carlo simulation to predict the PK/PD target of fT>MIC or modelling and simulation of time-kill curve data. Ceftobiprole, the paradigm compound, activity against two MRSA strains was determined, ATCC 33591 (MIC=2mg/L) and a clinical isolate (MIC=1mg/L). A two-subpopulation model accounting for drug degradation during the experiment adequately fit the time-kill curve data (concentration range 0.25-16× MIC). The PTA was calculated for plasma, skeletal muscle and subcutaneous adipose tissue based on data from a microdialysis study in healthy volunteers. A two-compartment model with distribution factors to account for differences between free serum and tissue interstitial space fluid concentration appropriately fit the pharmacokinetic data. Pharmacodynamic endpoints of fT>MIC of 30% or 40% and 1- or 2-log kill were used. The PTA was >90% in all tissues based on the PK/PD endpoint of fT>MIC >40%. The PTAs based on a 1- or 2-log kill from the time-kill experiments were lower than those calculated based on fT>MIC. The PTA of a 1-log kill was >90% for both MRSA isolates for plasma and skeletal muscle but was slightly below 90% for subcutaneous adipose tissue (both isolates ca. 88%). The results support a dosing regimen of 500mg three times daily as a 2-h intravenous infusion. This dose should be confirmed as additional pharmacokinetic data from various patient populations become available.

  4. The Skipping Rope Curve

    ERIC Educational Resources Information Center

    Nordmark, Arne; Essen, Hanno

    2007-01-01

    The equilibrium of a flexible inextensible string, or chain, in the centrifugal force field of a rotating reference frame is investigated. It is assumed that the end points are fixed on the rotation axis. The shape of the curve, the skipping rope curve or "troposkien", is given by the Jacobi elliptic function sn. (Contains 3 figures.)

  5. Anodic Polarization Curves Revisited

    ERIC Educational Resources Information Center

    Liu, Yue; Drew, Michael G. B.; Liu, Ying; Liu, Lin

    2013-01-01

    An experiment published in this "Journal" has been revisited and it is found that the curve pattern of the anodic polarization curve for iron repeats itself successively when the potential scan is repeated. It is surprising that this observation has not been reported previously in the literature because it immediately brings into…

  6. Flow-duration curves

    USGS Publications Warehouse

    Searcy, James Kincheon

    1959-01-01

    The flow-duration curve is a cumulative frequency curve that shows the percent of time specified discharges were equaled or exceeded during a given period. It combines in one curve the flow characteristics of a stream throughout the range of discharge, without regard to the sequence of occurrence. If the period upon which the curve is based represents the long-term flow of a stream, the curve may be used to predict the distribution of future flows for water- power, water-supply, and pollution studies. This report shows that differences in geology affect the low-flow ends of flow-duration curves of streams in adjacent basins. Thus, duration curves are useful in appraising the geologic characteristics of drainage basins. A method for adjusting flow-duration curves of short periods to represent long-term conditions is presented. The adjustment is made by correlating the records of a short-term station with those of a long-term station.

  7. Tornado-Shaped Curves

    ERIC Educational Resources Information Center

    Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio

    2017-01-01

    In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.

  8. Predicting streamflows in snowmelt-driven watersheds using the flow duration curve method

    NASA Astrophysics Data System (ADS)

    Kim, D.; Kaluarachchi, J.

    2014-05-01

    Predicting streamflows in snow-fed watersheds in the Western United States is important for water allocation. Since many of these watersheds are heavily regulated through canal networks and reservoirs, predicting expected natural flows and therefore water availability under limited data is always a challenge. This study investigates the applicability of the flow duration curve (FDC) method for predicting natural flows in gauged and regulated snow-fed watersheds. Point snow observations, air temperature, precipitation, and snow water equivalent were used to simulate the snowmelt process with the SNOW-17 model, and extended to streamflow simulation using the FDC method with a modified current precipitation index. For regulated watersheds, a parametric regional FDC method was applied to reconstruct natural flow. For comparison, a simplified tank model was used considering both lumped and semi-distributed approaches. The proximity regionalization method was used to simulate streamflows in the regulated watersheds with the tank model. The results showed that the FDC method is capable of producing satisfactory natural flow estimates in gauged watersheds when high correlation exists between current precipitation index and streamflow. For regulated watersheds, the regional FDC method produced acceptable river diversion estimates, but it seemed to have more uncertainty due to less robustness of the FDC method. In spite of its simplicity, the FDC method is a practical approach with less computational burden for studies with minimal data availability.

  9. CURVES: curve evolution for vessel segmentation.

    PubMed

    Lorigo, L M; Faugeras, O D; Grimson, W E; Keriven, R; Kikinis, R; Nabavi, A; Westin, C F

    2001-09-01

    The vasculature is of utmost importance in neurosurgery. Direct visualization of images acquired with current imaging modalities, however, cannot provide a spatial representation of small vessels. These vessels, and their branches which show considerable variations, are most important in planning and performing neurosurgical procedures. In planning they provide information on where the lesion draws its blood supply and where it drains. During surgery the vessels serve as landmarks and guidelines to the lesion. The more minute the information is, the more precise the navigation and localization of computer guided procedures. Beyond neurosurgery and neurological study, vascular information is also crucial in cardiovascular surgery, diagnosis, and research. This paper addresses the problem of automatic segmentation of complicated curvilinear structures in three-dimensional imagery, with the primary application of segmenting vasculature in magnetic resonance angiography (MRA) images. The method presented is based on recent curve and surface evolution work in the computer vision community which models the object boundary as a manifold that evolves iteratively to minimize an energy criterion. This energy criterion is based both on intensity values in the image and on local smoothness properties of the object boundary, which is the vessel wall in this application. In particular, the method handles curves evolving in 3D, in contrast with previous work that has dealt with curves in 2D and surfaces in 3D. Results are presented on cerebral and aortic MRA data as well as lung computed tomography (CT) data.

  10. Infinite swapping in curved spaces

    NASA Astrophysics Data System (ADS)

    Curotto, E.; Mella, Massimo

    2014-01-01

    We develop an extension of the infinite swapping and partial infinite swapping techniques [N. Plattner, J. D. Doll, P. Dupuis, H. Wang, Y. Liu, and J. E. Gubernatis, J. Chem. Phys. 135, 134111 (2011)] to curved spaces. Furthermore, we test the performance of infinite swapping and partial infinite swapping in a series of flat spaces characterized by the same potential energy surface model. We develop a second order variational algorithm for general curved spaces without the extended Lagrangian formalism to include holonomic constraints. We test the new methods by carrying out NVT classical ensemble simulations on a set of multidimensional toroids mapped by stereographic projections and characterized by a potential energy surface built from a linear combination of decoupled double wells shaped purposely to create rare events over a range of temperatures.

  11. Infinite swapping in curved spaces.

    PubMed

    Curotto, E; Mella, Massimo

    2014-01-07

    We develop an extension of the infinite swapping and partial infinite swapping techniques [N. Plattner, J. D. Doll, P. Dupuis, H. Wang, Y. Liu, and J. E. Gubernatis, J. Chem. Phys. 135, 134111 (2011)] to curved spaces. Furthermore, we test the performance of infinite swapping and partial infinite swapping in a series of flat spaces characterized by the same potential energy surface model. We develop a second order variational algorithm for general curved spaces without the extended Lagrangian formalism to include holonomic constraints. We test the new methods by carrying out NVT classical ensemble simulations on a set of multidimensional toroids mapped by stereographic projections and characterized by a potential energy surface built from a linear combination of decoupled double wells shaped purposely to create rare events over a range of temperatures.

  12. New Treatment Strategy for Apogeotropic Horizontal Canal Benign Paroxysmal Positional Vertigo

    PubMed Central

    e Maia, Francisco Zuma

    2016-01-01

    The apogeotropic variant of horizontal semicircular canal benign paroxysmal positional vertigo (HC-BPPV) is attributed to canalithiasis of the anterior arm or cupulolithiasis. Despite some therapeutic maneuvers, I propose a new treatment strategy for apogeotropic HC-BPPV that is designed to detach both the otoconial debris from the anterior arm of the semicircular canal and the debris that is attached to the utricular side of the cupula using inertia and gravity and based on simulations with a 3D biomechanical model. PMID:27942374

  13. Learning curve for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic lesions in a novel ex-vivo simulation model

    PubMed Central

    Gonzalez, J. M.; Cohen, J.; Gromski, M. A.; Saito, K.; Loundou, A.; Matthes, K.

    2016-01-01

    Background: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is essential in the management of digestive cancers. However, teaching and learning this technique remain challenging due to the lack of cost-effective models. Material and methods: This was a prospective experimental study using a complete porcine upper gastrointestinal ex-vivo organ package, placed in an Erlangen Active Simulator for Interventional Endoscopy (EASIE-R), and prepared with one cyst and two solid masses (2 cm). Five fellows inexperienced in EUS-FNA were enrolled, performing 10 procedures on each lesion, alternatively. The total time, number of attempts for success, of needle view losses, and of scope handling were recorded, associated with an independent skills rating by procedure. We compared the first 15 procedures with the last 15 for each fellow. Results: The fellows successfully performed all procedures in 2 to 40 minutes, requiring 1 to 6 attempts. All (5/5) improved their total time taken (P < 0.001), number of times when the EUS view of the needle was lost (P < 0.05), scope handling (P < 0.005), and skills rating (P < 0.001), whereas 4/5 (80 %) improved their number of attempts. The overall evaluation showed a significant decrease (P < 0.001) in the total time taken (11.2 ± 7.8 vs 4.3 ± 2.2 minutes), number of attempts (2.6 ± 1.2 vs 1.2 ± 0.7), number of times when the EUS view of the needle was lost (2.3 ± 2 vs 0.5 ± 0.7), and need for scope handling (1.1 ± 1.7 vs 0.1 ± 0.2). We also observed an improvement in skills rating (5 ± 1.9 vs. 7.7 ± 1.1). Conclusion: This newly designed ex-vivo model seems to be an effective way to improve the initial learning of EUS-FNA, by performing 30 procedures. PMID:27995190

  14. Canal Shaping with One Shape File and Twisted Files: A Comparative Study

    PubMed Central

    Kumar, Vedati Santosh; Aravind, Kumbakonam; Kumar, Harish TVS; Vishal M, Bharath; Vizaikumar, Vasudha Nelluri; Das, Rupali; Vamsilatha, K

    2014-01-01

    Aim: The aim of this study was to compare the shaping ability of two different rotary Nickel –Titanium (Ni-Ti) files, One shape file and Twisted files in a simulated artificial canals. Materials and Methods: A total of 40 endodontic training blocks were used in this study and divided in two groups consisting of 20 each ( n = 20) and the shaping ability was accessed based on the left over ink stain in the artificial canal. Results: Image proplus analysis software and stereomicroscope were used for analysing the shaping ability of the files and statistical analysis was done by SPSS software. Twisted files showed better shaping ability compared to one shape file both experimentally and statistically. Conclusion: It can be concluded that twisted files shaped the canals better then one shape file. PMID:25654059

  15. Numerical Analysis of the Influence of the Auditory External Canal Geometry on the Human Hearing Response

    NASA Astrophysics Data System (ADS)

    Caminos, Luis; Garcia-Gonzalez, Antonio; Gonzalez-Herrera, Antonio

    2011-11-01

    This paper presents the analysis and discussion about different effects of the external auditory canal (EAC) geometry on the response of the human hearing system. Simulation has been made by means of 3D finite element models which included EAC and a model of the ossicular-eardrum system. Different EAC geometries were constructed, coupled to a middle ear model validated in previous works. The EAC geometry is based on anatomical measurements taken from the literature. The relative position and orientation of the tympanic membrane and section reduction of the canal at the isthmus were studied and analyzed with a harmonic analysis. A sound pressure level of 90 dB was applied at the canal entrance and through fluid-structure coupling, the pressures in the umbo and the displacements of umbo and stapes footplate were measured in a frequency range from 100 Hz to 20000 Hz.

  16. Preceramic irrigation canals in the Peruvian Andes.

    PubMed

    Dillehay, Tom D; Eling, Herbert H; Rossen, Jack

    2005-11-22

    One of the most important developments in the existence of human society was the successful shift from a subsistence economy based on foraging to one primarily based on food production derived from cultivated plants and domesticated animals. The shift to plant food production occurred in only a few independent centers around the world and involved a commitment to increased sedentism and social interaction and to permanent agricultural fields and canals. One center was Peru, where early civilization and food production were beginning to develop by at least 4,500 years ago. New archeological evidence points to 5,400- and possible 6,700-year-old small-scale gravity canals in a circumscribed valley of the western Andean foothills in northern Peru that are associated with farming on low terrace benches at the foot of alluvial fans in areas where the canals are drawn from hydraulically manageable small lateral streams. This evidence reveals early environmental manipulation and incipient food production in an artificially created wet agroecosystem rather than simply the intensive harvesting or gardening of plants in moist natural areas. This finding is different from previously conceived notions, which expected early canals in lower-elevated, broad coastal valleys. The evidence also points to communal organization of labor to construct and maintain the canals and to the scheduling of daily activities beyond individual households. The development of early organized irrigation farming was combined with a hunting and gathering economy to support an increase in the local population size.

  17. Preceramic irrigation canals in the Peruvian Andes

    PubMed Central

    Dillehay, Tom D.; Eling, Herbert H.; Rossen, Jack

    2005-01-01

    One of the most important developments in the existence of human society was the successful shift from a subsistence economy based on foraging to one primarily based on food production derived from cultivated plants and domesticated animals. The shift to plant food production occurred in only a few independent centers around the world and involved a commitment to increased sedentism and social interaction and to permanent agricultural fields and canals. One center was Peru, where early civilization and food production were beginning to develop by at least 4,500 years ago. New archeological evidence points to 5,400- and possible 6,700-year-old small-scale gravity canals in a circumscribed valley of the western Andean foothills in northern Peru that are associated with farming on low terrace benches at the foot of alluvial fans in areas where the canals are drawn from hydraulically manageable small lateral streams. This evidence reveals early environmental manipulation and incipient food production in an artificially created wet agroecosystem rather than simply the intensive harvesting or gardening of plants in moist natural areas. This finding is different from previously conceived notions, which expected early canals in lower-elevated, broad coastal valleys. The evidence also points to communal organization of labor to construct and maintain the canals and to the scheduling of daily activities beyond individual households. The development of early organized irrigation farming was combined with a hunting and gathering economy to support an increase in the local population size. PMID:16284247

  18. Effect of dowel space preparation on the apical seal of root canal fillings.

    PubMed

    Raiden, G C; Gendelman, H

    1994-06-01

    The effect of post preparation on the apical seal was studied using simulated root canals. The maximum level of removal was tested with residual fillings 1, 2, 3, and 4 mm long. All of the artificial canals were filled with gutta-percha, Grossman's sealer, and lateral condensation. The removal was immediate and carried out with warm pluggers and the dowel space was completed with a Peeso drill. Stainless steel posts were cemented with zinc phosphate cement in the free space of the root canals. The coronal access of the canals was sealed with temporary fillings. After setting the materials, the specimens were immersed in a 2% methylene blue dye solution for 72 h and were observed with a measuring microscope. The final length of the apical fillings was found to be different from the intended length in every group. As far as leakage was concerned, 1, 2, and 3 mm-long fillings did not show a significant difference when compared with the negative control group (that is to say, filled canals where no dowel space was created). In the 4 mm fillings the leakage value was zero. These findings may be of clinical importance when restoring short roots.

  19. Mechanics of Curved Folds

    NASA Astrophysics Data System (ADS)

    Dias, Marcelo A.; Santangelo, Christian D.

    2011-03-01

    Despite an almost two thousand year history, origami, the art of folding paper, remains a challenge both artistically and scientifically. Traditionally, origami is practiced by folding along straight creases. A whole new set of shapes can be explored, however, if, instead of straight creases, one folds along arbitrary curves. We present a mechanical model for curved fold origami in which the energy of a plastically-deformed crease is balanced by the bending energy of developable regions on either side of the crease. Though geometry requires that a sheet buckle when folded along a closed curve, its shape depends on the elasticity of the sheet. NSF DMR-0846582.

  20. Calculating the equation of state parameters and predicting the spinodal curve of isotactic polypropylene/poly(ethylene-co-octene) blend by molecular dynamics simulations combined with Sanchez-Lacombe lattice fluid theory.

    PubMed

    Li, Zhan-Wei; Lu, Zhong-Yuan; Sun, Zhao-Yan; Li, Ze-Sheng; An, Li-Jia

    2007-05-31

    Molecular dynamics simulations are adopted to calculate the equation of state characteristic parameters P*, rho*, and T* of isotactic polypropylene (iPP) and poly(ethylene-co-octene) (PEOC), which can be further used in the Sanchez-Lacombe lattice fluid theory (SLLFT) to describe the respective physical properties. The calculated T* is a function of the temperature, which was also found in the literature. To solve this problem, we propose a Boltzmann fitting of the data and obtain T* at the high-temperature limit. With these characteristic parameters, the pressure-volume-temperature (PVT) data of iPP and PEOC are predicted by the SLLFT equation of state. To justify the correctness of our results, we also obtain the PVT data for iPP and PEOC by experiments. Good agreement is found between the two sets of data. By integrating the Euler-Lagrange equation and the Cahn-Hilliard relation, we predict the density profiles and the surface tensions for iPP and PEOC, respectively. Furthermore, a recursive method is proposed to obtain the characteristic interaction energy parameter between iPP and PEOC. This method, which does not require fitting to the experimental phase equilibrium data, suggests an alternative way to predict the phase diagrams that are not easily obtained in experiments. As an example, in the framework of SLLFT, the spinodal curve for the iPP/PEOC blend is predicted at the low molecular weights that are used in the simulations.

  1. Tooth anatomy risk factors influencing root canal working length accessibility

    PubMed Central

    Tang, Lu; Sun, Tuo-qi; Gao, Xiao-jie; Zhou, Xue-dong; Huang, Ding-ming

    2011-01-01

    The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth location), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P<0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure. PMID:21789962

  2. Quantifying canal leakage rates using a mass-balance approach and heat-based hydraulic conductivity estimates in selected irrigation canals, western Nebraska, 2007 through 2009

    USGS Publications Warehouse

    Hobza, Christopher M.; Andersen, Michael J.

    2010-01-01

    The water supply in areas of the North Platte River Basin in the Nebraska Panhandle has been designated as fully appropriated or overappropriated by the Nebraska Department of Natural Resources (NDNR). Enacted legislation (Legislative Bill 962) requires the North Platte Natural Resources District (NPNRD) and the NDNR to develop an Integrated Management Plan (IMP) to balance groundwater and surface-water supply and demand in the NPNRD. A clear understanding of the groundwater and surface-water systems is critical for the development of a successful IMP. The primary source of groundwater recharge in parts of the NPNRD is from irrigation canal leakage. Because canal leakage constitutes a large part of the hydrologic budget, spatially distributing canal leakage to the groundwater system is important to any management strategy. Surface geophysical data collected along selected reaches of irrigation canals has allowed for the spatial distribution of leakage on a relative basis; however, the actual magnitude of leakage remains poorly defined. To address this need, the U.S. Geological Survey, in cooperation with the NPNRD, established streamflow-gaging stations at upstream and downstream ends from two selected canal reaches to allow a mass-balance approach to be used to calculate daily leakage rates. Water-level and sediment temperature data were collected and simulated at three temperature monitoring sites to allow the use of heat as a tracer to estimate the hydraulic conductivity of canal bed sediment. Canal-leakage rates were estimated by applying Darcy's Law to modeled vertical hydraulic conductivity and either the estimated or measured hydraulic gradient. This approach will improve the understanding of the spatial and temporal variability of canal leakage in varying geologic settings identified in capacitively coupled resistivity surveys. The high-leakage potential study reach of the Tri-State Canal had two streamflow-gaging stations and two temperature monitoring

  3. Low-frequency otolith and semicircular canal interactions after canal inactivation

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Merfeld, D. M.; Hess, B. J.

    2000-01-01

    During sustained constant velocity and low-frequency off-vertical axis rotations (OVAR), otolith signals contribute significantly to slow-phase eye velocity. The adaptive plasticity of these responses was investigated here after semicircular canal plugging. Inactivation of semicircular canals results in a highly compromised and deficient vestibulo-ocular reflex (VOR). Based on the VOR enhancement hypothesis, one could expect an adaptive increase of otolith-borne angular velocity signals due to combined otolith/canal inputs after inactivation of the semicircular canals. Contrary to expectations, however, the steady-state slow-phase velocity during constant velocity OVAR decreased in amplitude over time. A similar progressive decrease in VOR gain was also observed during low-frequency off-vertical axis oscillations. This response deterioration was present in animals with either lateral or vertical semicircular canals inactivated and was limited to the plane(s) of the plugged canals. The results are consistent with the idea that the low-frequency otolith signals do not simply enhance VOR responses. Rather, the nervous system appears to correlate vestibular sensory information from the otoliths and the semicircular canals to generate an integral response to head motion.

  4. Highly curved microchannel plates

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Cully, S.; Warren, J.; Gaines, G. A.; Priedhorsky, W.; Bloch, J.

    1990-01-01

    Several spherically curved microchannel plate (MCP) stack configurations were studied as part of an ongoing astrophysical detector development program, and as part of the development of the ALEXIS satellite payload. MCP pairs with surface radii of curvature as small as 7 cm, and diameters up to 46 mm have been evaluated. The experiments show that the gain (greater than 1.5 x 10 exp 7) and background characteristics (about 0.5 events/sq cm per sec) of highly curved MCP stacks are in general equivalent to the performance achieved with flat MCP stacks of similar configuration. However, gain variations across the curved MCP's due to variations in the channel length to diameter ratio are observed. The overall pulse height distribution of a highly curved surface MCP stack (greater than 50 percent FWHM) is thus broader than its flat counterpart (less than 30 percent). Preconditioning of curved MCP stacks gives comparable results to flat MCP stacks, but it also decreases the overall gain variations. Flat fields of curved MCP stacks have the same general characteristics as flat MCP stacks.

  5. Accurate Measurement of Canal Length during Root Canal Treatment: An In Vivo Study

    PubMed Central

    Sadaf, Durre; Ahmad, Muhammad Zubair

    2015-01-01

    Objectives: To assess the consistency and accuracy of Electronic Apex Locator (EAL) (Root ZXII) in individual canals and its association with other clinical variables. Study Design: Cross-Sectional study. Place of study: Dental section of the Aga Khan University Hospital, Karachi, Pakistan. Materials and Methods: Working length was measured by EAL in 180 patients requiring endodontic therapy in molar and premolar teeth. The effects of clinical variables e.g. gender and pulpal status on the consistency and accuracy of EAL were recorded. Performance of apex locator was considered “Consistent” when the scale bar was stable and moved only in correspondence to the movement of file in the root canal. Accuracy was determined by inserting the file at the working length determined by the EAL and periapical view of radiograph was taken using paralleling technique. Estimated working length was considered accurate when the file tip was located 0-2mm short of the radiographic apex. If the file was overextended from the radiographic apex, it showed dysfunction of the EAL. Results: Consistency of EAL was found 97.6% in distobuccal canals, 91.1% in palatal canals, 73.7% in mesiolingual canals, 83.3% in mesiobuccal and 80.2% in distal canals. Accuracy of EAL was 91.4% in mesiolingual canal, 92% in mesiobuccal, and 90.2% in Palatal and 93.2% in distal canal. Conclusion: Consistency of electronic apex locator vary in different canals, however consistent measurements are highly accurate. No significant association was found between other clinical variables with the consistency and accuracy of EAL.

  6. OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM ...

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

    OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM FROM DIRECTION OF KACHESS DAM. VIEW TO NORTH - Kachess Dam, 1904 Cascade Canal Company Crib Dam, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

  7. CANAL EXITING FLUME AND BEGINNING EARTHLINED MAIN SECTION AT MOUTH ...

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

    CANAL EXITING FLUME AND BEGINNING EARTH-LINED MAIN SECTION AT MOUTH OF PLATTE RIVER CANYON. VIEW TO WEST - High Line Canal, Mouth of South Platte River to confluence with Second Creek, Denver, Denver County, CO

  8. 77. ROOSEVELT POWER CANAL LOCATION MAP, WORK TO BE DONE ...

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

    77. ROOSEVELT POWER CANAL LOCATION MAP, WORK TO BE DONE BY CONTRACT Courtesy of Dept. of the Interior, Bureau of Reclamation, Salt River Project - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  9. Stratification and enumeration of Boolean functions by canalizing depth

    NASA Astrophysics Data System (ADS)

    He, Qijun; Macauley, Matthew

    2016-01-01

    Boolean network models have gained popularity in computational systems biology over the last dozen years. Many of these networks use canalizing Boolean functions, which has led to increased interest in the study of these functions. The canalizing depth of a function describes how many canalizing variables can be recursively "picked off", until a non-canalizing function remains. In this paper, we show how every Boolean function has a unique algebraic form involving extended monomial layers and a well-defined core polynomial. This generalizes recent work on the algebraic structure of nested canalizing functions, and it yields a stratification of all Boolean functions by their canalizing depth. As a result, we obtain closed formulas for the number of n-variable Boolean functions with depth k, which simultaneously generalizes enumeration formulas for canalizing, and nested canalizing functions.

  10. 4. VIEW SHOWING EXCAVATION IN ARIZONA CANAL, 8 MILES NORTHEAST ...

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

    4. VIEW SHOWING EXCAVATION IN ARIZONA CANAL, 8 MILES NORTHEAST OF PHOENIX. NOTE MEN DRILLING AND EXCAVATING IN OPERATION; CAMELBACK MOUNTAIN IN THE DISTANCE Photographer: Walter J. Lubken. No date - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ

  11. NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM ...

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

    NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM (LATER FILL ENCROACHING LEFT) NEAR CENTER OF THIS STRETCH; VIEW TO SOUTHWEST - Blackstone Canal Worcester-Millbury Segment, Eastern bank of Blackstone River, Millbury, Worcester County, MA

  12. Surgical endodontic management of infected lateral canals of maxillary incisors

    PubMed Central

    2015-01-01

    This case report presents surgical endodontic management outcomes of maxillary incisors that were infected via the lateral canals. Two cases are presented in which endodontically-treated maxillary central incisors had sustained lateral canal infections. A surgical endodontic treatment was performed on both teeth. Flap elevation revealed vertical bone destruction along the root surface and infected lateral canals, and microscopy revealed that the lateral canals were the origin of the lesions. After the infected lateral canals were surgically managed, both teeth were asymptomatic and labial fistulas were resolved. There were no clinical or radiographic signs of surgical endodontic management failure at follow-up visits. This case report highlights the clinical significance and surgical endodontic management of infected lateral canal of maxillary incisor. It is important to be aware of root canal anatomy variability in maxillary incisors. Maxillary central incisors infected via the lateral canal can be successfully managed by surgical endodontic treatment. PMID:25671217

  13. 23. Photocopy of photograph (original print at Gage Canal Company ...

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

    23. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1917. VIEW OF FLUME NO. 3 OF GAGE IRRIGATION CANAL AND NEW 66' REINFORCED CONCRETE PIPELINE - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  14. 24. Photocopy of photograph (original print at Gage Canal Company ...

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

    24. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1939. VIEW OF SAND PUMP HOUSE AT THE HEAD OF THE GAGE IRRIGATION CANAL - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  15. 26. Photocopy of photograph (original print at Gage Canal Company ...

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

    26. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1931. VIEW OF CONSTRUCTION OF GUNITE INVERT SIPHON REPLACING FLUME NO. 10 ON GAGE IRRIGATION CANAL - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  16. 27. Photocopy of photograph (original print at Gage Canal Company ...

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

    27. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1913. TIGHTENING JOINTS AND ADJUSTING PLATES ON STEEL FLUME AT MOCKINGBIRD DAM ON THE GAGE IRRIGATION CANAL - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  17. 22. Photocopy of photograph (original print at Gage Canal Company ...

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

    22. Photocopy of photograph (original print at Gage Canal Company Office), photographer and date unknown. 'FLUME NO. 9, 'GAGE CANAL SYSTEM,' RIVERSIDE, CAL.' VIEW OF FLUME OVER TEQUESQUITE ARROYO. - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  18. 29. Photocopy of photograph (original print at Gage Canal Company ...

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

    29. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1926. CENTRIFUGAL PUMPS AT OLIVEWOOD PUMPING STATION ON THE GAGE IRRIGATION CANAL - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  19. 9. VIEW SHOWING ARIZONA CANAL WITH CITRUS ORCHARDS, FACING NORTH. ...

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

    9. VIEW SHOWING ARIZONA CANAL WITH CITRUS ORCHARDS, FACING NORTH. CAMELBACK MOUNTAIN IS IN THE BACKGROUND Photographer: unknown. No date - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ

  20. 28. Photocopy of photograph (original print at Gage Canal Company ...

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

    28. Photocopy of photograph (original print at Gage Canal Company Office), photographer unknown, ca. 1913. CONSTRUCTION OF CORE WALL AT MOCKINGBIRD DAM ON THE GAGE IRRIGATION CANAL - California Citrus Heritage Recording Project, Riverside, Riverside County, CA

  1. 2. VIEW NORTHWEST, GENERAL VIEW SHOWING RAILWAY CANAL TRUSS IN ...

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

    2. VIEW NORTHWEST, GENERAL VIEW SHOWING RAILWAY CANAL TRUSS IN CENTER, RAILWAY RIVER TRUSS ON LEFT, HIGHWAY TRUSSES IN BACKGROUND - White Rock Bridge, Spanning Pawcatuck River & White Rock Canal, Westerly, Washington County, RI

  2. 5. VIEW SOUTHWEST, INTERIOR CANAL WALL (Original Fabric) Bald ...

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

    5. VIEW SOUTHWEST, INTERIOR CANAL WALL (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  3. 7. REMAINS OF PLANK WALL WITHIN CANAL CONSTRUCTED TO PROTECT ...

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

    7. REMAINS OF PLANK WALL WITHIN CANAL CONSTRUCTED TO PROTECT OUTSIDE CANAL BANK, LOOKING SOUTHWEST. NOTE CROSS SUPPORT POLES EXTENDING TO HILLSIDE. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  4. 6. REMAINS OF PLANK WALL NAILED TO POSTS WITHIN CANAL ...

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

    6. REMAINS OF PLANK WALL NAILED TO POSTS WITHIN CANAL CONSTRUCTED TO PROTECT OUTSIDE CANAL BANK. VIEW IS TO THE WEST. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  5. MAIN CANAL HEADWORKS, FROM DOWNSTREAM (TO RIGHT), NOTE SAND AND ...

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

    MAIN CANAL HEADWORKS, FROM DOWNSTREAM (TO RIGHT), NOTE SAND AND SILT SLUICE GATE FOR DIVERSION DAM ON LEFT, VIEW TO NORTHWEST - Salmon Creek Diversion Dam, Main Canal Headworks, Salmon Creek, Okanogan, Okanogan County, WA

  6. 4. VIEW LOOKING NORTH OF SAN TAN INDIAN CANAL WITH ...

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

    4. VIEW LOOKING NORTH OF SAN TAN INDIAN CANAL WITH NEWER CHECK AND TURNOUT STRUCTURE IN FOREGROUND - San Carlos Irrigation Project, San Tan Indian Canal, North of Gila River, Coolidge, Pinal County, AZ

  7. 12. CONCRETE DROP STRUCTURE ON NORTH SIDE CANAL WITH TWO ...

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

    12. CONCRETE DROP STRUCTURE ON NORTH SIDE CANAL WITH TWO TURNOUTS IN BACKGROUND, T4S R7E S24. VIEW LOOKING EAST - San Carlos Irrigation Project, North Side Canal, North of Gila River, Coolidge, Pinal County, AZ

  8. 19. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING NORTHEAST ...

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

    19. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING NORTHEAST FROM 56TH STREET, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  9. 26. VIEW OF THE PEDESTRIAN BRIDGE CROSSING GRAND CANAL AT ...

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

    26. VIEW OF THE PEDESTRIAN BRIDGE CROSSING GRAND CANAL AT 30TH STREET IN PHOENIX, LOOKING WEST, Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  10. 21. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST ...

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

    21. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST LOCATION UNKNOWN. THE WIDE DRY BED OF THE SALT RIVER SPANS THE BACKGROUND. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  11. 10. Tempe Canal, looking south from Apache Boulevard, showing new ...

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

    10. Tempe Canal, looking south from Apache Boulevard, showing new apartments and old farm silos. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  12. 20. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTHEAST ...

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

    20. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTHEAST FROM 56TH STREET, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  13. 6. Tempe Crosscut Canal, looking west from Division Gates. Lateral ...

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

    6. Tempe Crosscut Canal, looking west from Division Gates. Lateral at left is for local delivery of irrigation water. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  14. 17. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH ...

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

    17. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH FROM GROVE PARKWAY, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  15. 18. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH ...

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

    18. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH TOWARD ELLIOT ROAD, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  16. 32. VIEW OF TERMINUS OF GRAND CANAL, SHOWING TURNOUT GATES, ...

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

    32. VIEW OF TERMINUS OF GRAND CANAL, SHOWING TURNOUT GATES, LOOKING SOUTHWEST. WASTE WATER IS TURNED INTO THE BED OF NEW RIVER. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  17. 31. VIEW SHOWING DEMOSSING ALONG GRAND CANAL. THE DRAGLINE SCOOPS ...

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

    31. VIEW SHOWING DEMOSSING ALONG GRAND CANAL. THE DRAGLINE SCOOPS UP AQUATIC WEEDS AND DEPOSITS THEM IN A DUMP TRUCK. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  18. View north, west (back) wall of canal, mu shed in ...

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

    View north, west (back) wall of canal, mu shed in background. - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Long Slip Canal, New Jersey Transit Hoboken Rail Yard, Hoboken, Hudson County, NJ

  19. 1. LOOKING WEST ON LEHIGH CANAL, GRAPHITE MILL IN FOREGROUND ...

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

    1. LOOKING WEST ON LEHIGH CANAL, GRAPHITE MILL IN FOREGROUND - Pettinos Brothers Graphite Manufacturing Mill, On Sand Island, south side of Lehigh Canal, west of Hill-to-Hill Bridge, Bethlehem, Northampton County, PA

  20. 122. Jet Lowe, Photographer, July 1978. POWER CANAL LOOKING NORTH. ...

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

    122. Jet Lowe, Photographer, July 1978. POWER CANAL LOOKING NORTH. WOODEN LINING OF CANAL STILL VISIBLE NEXT TO ROCKS. - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  1. Environmental Sampling in the Panama Canal Zone. 1 December 1976.

    DTIC Science & Technology

    1977-01-20

    disappearance of even persistent pesticides may be exceptionally rapid in the tropical climate of the Canal Zone. This report also discusses the nature and scope of pest management operations in the Canal Zone.

  2. Bitter Root Irrigation district canal, looking east, typical section and ...

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

    Bitter Root Irrigation district canal, looking east, typical section and crossing - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  3. 58. View of lined canal looking west from road bridge ...

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

    58. View of lined canal looking west from road bridge crossing lined canal. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  4. 10. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW ...

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

    10. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW LOOKING EAST FROM PICACHO RESERVOIR INLET CHANNEL - San Carlos Irrigation Project, Marin Canal, Amhurst-Hayden Dam to Picacho Reservoir, Coolidge, Pinal County, AZ

  5. 2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ...

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

    2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ITS WAY TOWARD THE CEMENT MILL Photographer: Walter J. Lubken, November 19, 1907 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  6. 7. VIEW OF MAIN CANAL, LOOKING SOUTH, IMMEDIATELY DOWNSTREAM FROM ...

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

    7. VIEW OF MAIN CANAL, LOOKING SOUTH, IMMEDIATELY DOWNSTREAM FROM THE SNAKE RIVER VALLEY IRRIGATION DISTRICT, SECTION 34, T2N, R37E - Woodville Canal Company, West side of Snake River (River Mile 796), Woodville, Bingham County, ID

  7. 12. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND ...

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

    12. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND BARTON ROAD SHOWING BEGINNING OF SIPHON, DATED '1952' - Gage Irrigation Canal, Running from Santa Ana River to Arlington Heights, Riverside, Riverside County, CA

  8. [Radio-anatomical variants of the optic canal].

    PubMed

    Bourjat, P; Bittighoffer, B

    1984-10-01

    Two variants of the optic canal are described by the same patient. During the foetal development, the optic canal and the orbital fissure are first separated by an anterior strut, then by a posterior strut, who secondary fuse into a single optic strut. The keyhole anomaly of the optic canal results from the absence of the posterior optic strut. The duplicate cranial opening of the optic canal results from the absence of fusion of the anterior and posterior struts.

  9. 28. MAIN CANAL Photographic copy of historic photo, July ...

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

    28. MAIN CANAL - Photographic copy of historic photo, July 18, 1906 (original print located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) J.J. Lubken, photographer 'LOOKING SOUTH FROM STATION 413, ON THE MAIN CANAL, SHOWING THE REMODLING SIC OF THE OLD PECOS VALLEY IRRIGATING CANAL' - Carlsbad Irrigation District, Main Canal, 4 miles North to 12 miles Southeast of Carlsbad, Carlsbad, Eddy County, NM

  10. 14. VIEW OF WESTERN CANAL AT THE SALT RIVER PROJECT'S ...

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

    14. VIEW OF WESTERN CANAL AT THE SALT RIVER PROJECT'S KYRENE STEAM POWER PLANT, TEMPE. THE WESTERN CANAL BEGINS TO TURN NORTH AT THIS POINT, AND DIVERTS WATER TO THE HIGHLINE PUMP PLANT AND THE KYRENE LATERAL. THE KYRENE PLANT INLET (LEFT-CENTER) ALSO DIVERTS CANAL WATER FOR PLANT OPERATION AND COOLING. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

  11. 21. VIEW OF NORTHERN BRANCH OF HIGHLINE CANAL, SECTION 1, ...

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

    21. VIEW OF NORTHERN BRANCH OF HIGHLINE CANAL, SECTION 1, T1S-R3E, SHOWING NON-PROJECT LAND, STILL DESERT, IN FOREGROUND AND CULTIVATED FIELDS OF THE SALT RIVER PROJECT BELOW THE CANAL, LOOKING NORTH. A SMALL PORTION OF NON-IRRIGABLE LAND BELOW THE CANAL IS SHOWN AT LEFT, March 1990 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  12. 13. VIEW OF WESTERN CANAL EAST OF CARRIAGE LANE IN ...

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

    13. VIEW OF WESTERN CANAL EAST OF CARRIAGE LANE IN TEMPE, SHOWING DROP STRUCTURE AND GROUNDWATER PUMP. THIS IS THE LAST OF FOUR PUMPS WHICH FEED DIRECTLY INTO THE CANAL BETWEEN ALMA SCHOOL ROAD AND PRICE ROAD. ON THIS DAY, ALL FOUR PUMPS, OPERATING AT FULL OUTPUT, HAVE CONSIDERABLY SWELLED THE FLOW TO THE CANAL. NOTE THE OLD FASHIONED BRICKWORK ON THE NORTH BANK. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

  13. 75 FR 39632 - Regulated Navigation Area; Gulf Intracoastal Waterway, Inner Harbor Navigation Canal, Harvey...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ..., Inner Harbor Navigation Canal, Harvey Canal, Algiers Canal, New Orleans, LA; Correction ACTION: Interim... Navigation Canal, Harvey Canal, Algiers Canal, New Orleans, LA into the Code of Federal Regulations. That... Commander (LCDR) Marty Daniels, Coast Guard; telephone (504) 565-5044, e-mail...

  14. 155. Photocopy of transit book (taken from Twin Falls Canal ...

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

    155. Photocopy of transit book (taken from Twin Falls Canal Company Surveyor's Transit Book #405T, Page 1, #46 Division One). STATEMENT RE: SURVEY ALIGNMENT 3/03, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  15. 159. Photocopy of written record (taken from Twin Falls Canal ...

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

    159. Photocopy of written record (taken from Twin Falls Canal Company Low Line Book #1, pp. 76,77). RECORD OF BORROW AT LOW LINE SIPHON. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  16. 156. Photocopy of written record (taken from Twin Falls Canal ...

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

    156. Photocopy of written record (taken from Twin Falls Canal Company, Low Line Book #1, pp.2,3). LOW LINE CONTRACTORS AND BORROW RECORD. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  17. 31. MAIN CANAL Photographic copy of historic photo, December ...

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

    31. MAIN CANAL - Photographic copy of historic photo, December 13, 1939 (original print in '1939 Annual Report of the Carlsbad Project,' located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) photographer unknown 'LINING MAIN CANAL AROUND GYP BEND' - Carlsbad Irrigation District, Main Canal, 4 miles North to 12 miles Southeast of Carlsbad, Carlsbad, Eddy County, NM

  18. 192. Photocopy of drawing, Twin Falls Canal Company, date unknown. ...

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

    192. Photocopy of drawing, Twin Falls Canal Company, date unknown. TOPOGRAPHICAL MAP (DAM DRAWN IN), MILNER SITE, TWIN FALLS COUNTY, MILNER, IDAHO; RIGHT SIDE OF MAP (LEFT ON ID-15-183). - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  19. 183. Photocopy of map (Twin Falls Canal Company). TOPOGRAPHICAL MAP ...

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

    183. Photocopy of map (Twin Falls Canal Company). TOPOGRAPHICAL MAP OF MILNER DAM SITE, TWIN FALLS COUNTY, MILNER, IDAHO; MAP, LEFT SIDE ONLY. CROSS REFERENCE: ID-15-192. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  20. 187. Photocopy of drawing, Twin Falls Canal Company, date unknown. ...

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

    187. Photocopy of drawing, Twin Falls Canal Company, date unknown. TOPOGRAPHICAL MAP OF MILNER DAM LOCATION, TWIN FALLS COUNTY, MILNER, IDAHO; BLUEPRINT MAP. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  1. 70. GENERAL VIEW OF CANAL IN DOVER LOOKING EAST. WHAT ...

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

    70. GENERAL VIEW OF CANAL IN DOVER LOOKING EAST. WHAT APPEARS TO BE A SWING BRIDGE IS VISIBLE ACROSS CANAL ON RIGHT SIDE OF PHOTOGRAPH (NOTE THAT THIS MAY ALSO BE A LIFT BRIDGE WITH THE LIFT EQUIPMENT REMOVED). - Morris Canal, Phillipsburg, Warren County, NJ

  2. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  3. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  4. 21 CFR 872.3820 - Root canal filling resin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Root canal filling resin. 872.3820 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3820 Root canal filling resin. (a) Identification. A root canal filling resin is a device composed of material, such as methylmethacrylate,...

  5. 11. Tempe Canal, looking north from the Superstition Freeway at ...

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

    11. Tempe Canal, looking north from the Superstition Freeway at the point where the canal turns west toward the Superstition flume. Equipment in center is beginning excavation for the pipe headworks. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  6. 13. Tempe Canal along Price Road, looking north from Baseline ...

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

    13. Tempe Canal along Price Road, looking north from Baseline Road. This is the section of the canal which will be piped. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  7. 16. VIEW OF HIGHLINE CANAL PIPELINE OUTLET, SHOWING THE OUTLET, ...

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

    16. VIEW OF HIGHLINE CANAL PIPELINE OUTLET, SHOWING THE OUTLET, A GROUNDWATER PUMP (LEFT), AND THE SOUTH BRANCH OF THE CANAL (FOREGROUND), August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  8. 20. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING EAST ...

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

    20. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING EAST FROM SOUTH BANK NEAR SETTLING BASIN (see HAER Photograph No. AZ-30-17, Crosscut Hydro Plant). THE LARGE FOREGROUND PIPE CARRIED WATER ACROSS THE CANAL FROM THE SETTLING BASIN TO THE CROSSCUT STEAM PLANT. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  9. 82. ROOSEVELT POWER CANAL, SUGGESTED ARRANGEMENT FOR ELECTRICAL OPERATION OF ...

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

    82. ROOSEVELT POWER CANAL, SUGGESTED ARRANGEMENT FOR ELECTRICAL OPERATION OF SLUICE GATES AND CANAL INTAKE GATES AT DIVERSION DAM Courtesy of Dept. of the Interior, Bureau of Reclamation, Salt River Project, Arizona - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  10. 14. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND ...

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

    14. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND BARTON ROAD, SHOWING OLD ROUTE OF CANAL VIADUCT ACROSS BARTON ROAD. SIPHON NOW GOES UNDER ROAD AND EMERGES AT RIGHT REAR BELOW TWO TELEPHONE POLES (SEE CA-120-15) - Gage Irrigation Canal, Running from Santa Ana River to Arlington Heights, Riverside, Riverside County, CA

  11. 157. Photocopy of drawing (taken from Twin Falls Canal Company ...

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

    157. Photocopy of drawing (taken from Twin Falls Canal Company Field Book #360, Page 75, entitled, 'Clay-Seam Cut-Off.' Cross-Reference: ID-15-153). MILNER DAM SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  12. 153. Photocopy of drawing (taken from Twin Falls Canal Company ...

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

    153. Photocopy of drawing (taken from Twin Falls Canal Company Field Book #360, Page 74, entitled, 'Clay-Seam Cut-Off.' Cross-Reference: ID-15-157). MILNER DAM SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  13. Newer Root Canal Irrigants in Horizon: A Review

    PubMed Central

    Jaju, Sushma; Jaju, Prashant P.

    2011-01-01

    Sodium hypochloride is the most commonly used endodontic irrigant, despite limitations. None of the presently available root canal irrigants satisfy the requirements of ideal root canal irrigant. Newer root canal irrigants are studied for potential replacement of sodium hypochloride. This article reviews the potential irrigants with their advantages and limitations with their future in endodontic irrigation. PMID:22190936

  14. 24. VIEW SHOWING WASTE GATES ON GRAND CANAL AT JUNCTION ...

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

    24. VIEW SHOWING WASTE GATES ON GRAND CANAL AT JUNCTION WITH OLD CROSSCUT NE/4, Sec. 7, TIN, R4E; LOOKING WEST. OLD CROSSCUT CANAL ENTERS FROM RIGHT. WASTE GATE ON LEFT EMPTIES INTO SALT RIVER BED Photographer: Kevin Kreisel-Coons, May 1990 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  15. 134. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN ...

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

    134. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN FALLS COUNTY, SOUTH OF HANSEN, IDAHO; VIEW OF LOW LINE AND POWER GATES, WEST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  16. 197. Photocopy of drawing, Twin Falls, Canal Company, date unknown. ...

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

    197. Photocopy of drawing, Twin Falls, Canal Company, date unknown. GATE STEMS AND LIFTING DEVICES, NO COUNTY; BLUEPRINT SKETCHES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  17. 132. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN ...

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

    132. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN FALLS COUNTY, SOUTH OF HANSEN, IDAHO; POWER GATES FOR HYDRO-ELECTRIC. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  18. Root Canal Stripping: Malpractice or Common Procedural Accident-An Ethical Dilemma in Endodontics.

    PubMed

    Ciobanu, Ionela Elisabeta; Rusu, Darian; Stratul, Stefan-Ioan; Didilescu, Andreea Cristina; Cristache, Corina Marilena

    2016-01-01

    Root canal stripping is defined as an oblong, vertical perforation that appears especially in the middle section of curved root canals during endodontic treatments with nickel-titanium (Ni-Ti) instruments. Its occurrence may drastically affect the outcome of the treatment, transforming a common otherwise efficient endodontic procedure into a complication such as tooth extraction. In order to discuss the ethical and legal consequences, two cases of dental strip perforations are herewith presented. Due to the existence of risk factors for dental strip perforation, experience of the clinician and the use of magnification and modern imagistic methods (CBCT) may avoid or reduce the frequency of this type of accidents. Under correct working circumstances, dental stripping should not be regarded as a malpractice but as a procedural accident. However, the patient must always be informed, before and during the endodontic procedure, about the event and the possible complications that may occur.

  19. Root Canal Stripping: Malpractice or Common Procedural Accident—An Ethical Dilemma in Endodontics

    PubMed Central

    Ciobanu, Ionela Elisabeta; Rusu, Darian; Didilescu, Andreea Cristina

    2016-01-01

    Root canal stripping is defined as an oblong, vertical perforation that appears especially in the middle section of curved root canals during endodontic treatments with nickel-titanium (Ni-Ti) instruments. Its occurrence may drastically affect the outcome of the treatment, transforming a common otherwise efficient endodontic procedure into a complication such as tooth extraction. In order to discuss the ethical and legal consequences, two cases of dental strip perforations are herewith presented. Due to the existence of risk factors for dental strip perforation, experience of the clinician and the use of magnification and modern imagistic methods (CBCT) may avoid or reduce the frequency of this type of accidents. Under correct working circumstances, dental stripping should not be regarded as a malpractice but as a procedural accident. However, the patient must always be informed, before and during the endodontic procedure, about the event and the possible complications that may occur. PMID:27672458

  20. The effects of a canalplasty and a canal wall reconstruction on perceived sound quality: preliminary results.

    PubMed

    van Spronsen, E; Brienesse, P; Ebbens, F A; Dreschler, W A

    2016-10-01

    Objective of this work was to evaluate the perceptual effect of the acoustic properties before and after canalplasty and a reconstruction of the posterior canal wall in revision modified radical cavity surgery. This is a prospective study. Twenty normal hearing subjects were presented six simulated sound conditions representing the acoustic properties of six different ear canals (two normal ears, and two pre- and postoperative conditions). The six different real ear unaided responses of these ear canals were used to filter Dutch sentences, resulting in six simulated sound conditions. A seventh unfiltered 'reference' condition was used for comparison. Sound quality was evaluated using a seven-point paired comparison rating and a visual analogue scale (VAS). Significant differences in sound quality were found between all conditions and the pre-operative cavity condition (all p < 0.001) using both the paired comparison rating and VAS. No significant differences in VAS were found comparing the other conditions with each other. But when using the paired comparison rating, the post-operative canalplasty condition and both the pre and post-operative cavity conditions differed significantly from the other conditions. This explorative study shows that altering the acoustics of the OEAC after a canalplasty and a reconstruction of the ear canal in revision modified radical cavity surgery results in perceivable changes in sound quality. It is likely that these changes are primarily due to volume changes. To which extent these changes are of clinical importance remains to be determined.

  1. Comparison of nine methods to estimate ear-canal stimulus levels

    PubMed Central

    Souza, Natalie N.; Dhar, Sumitrajit; Neely, Stephen T.; Siegel, Jonathan H.

    2014-01-01

    The reliability of nine measures of the stimulus level in the human ear canal was compared by measuring the sensitivity of behavioral hearing thresholds to changes in the depth of insertion of an otoacoustic emission probe. Four measures were the ear-canal pressure, the eardrum pressure estimated from it and the pressure measured in an ear simulator with and without compensation for insertion depth. The remaining five quantities were derived from the ear-canal pressure and the Thévenin-equivalent source characteristics of the probe: Forward pressure, initial forward pressure, the pressure transmitted into the middle ear, eardrum sound pressure estimated by summing the magnitudes of the forward and reverse pressure (integrated pressure) and absorbed power. Two sets of behavioral thresholds were measured in 26 subjects from 0.125 to 20 kHz, with the probe inserted at relatively deep and shallow positions in the ear canal. The greatest dependence on insertion depth was for transmitted pressure and absorbed power. The measures with the least dependence on insertion depth throughout the frequency range (best performance) included the depth-compensated simulator, eardrum, forward, and integrated pressures. Among these, forward pressure is advantageous because it quantifies stimulus phase. PMID:25324079

  2. The Panama Canal and Social Justice.

    ERIC Educational Resources Information Center

    Wilde, Margaret D., Ed.

    The booklet, designed to explore the issues of international justice in the context of the Gospel, reviews relations between the United States and Panama. It includes background materials and a study guide for parish leaders and other educators. The central question pertaining to the Panama Canal concerns the rights of the United States according…

  3. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington State pontoon highway bridge near Port Gamble operates as follows: (a) The draw shall open on signal if at least one hour's notice is given. The draw shall be opened horizontally for 300 feet unless...

  4. Comparative in vitro investigation of different methods for temporary root canal filling with aqueous suspensions of calcium hydroxide.

    PubMed

    Staehle, H J; Thomä, C; Müller, H P

    1997-06-01

    Three methods for temporarily filling root canals with calcium hydroxide pastes were compared. Each of 20 root canals of extracted, human, single-rooted teeth was shaped with hand instruments under standardized conditions up to ISO size 50 and filled using a syringe system, a lentulo spiral or an endodontic reamer. Quality of fillings was assessed radiographically and by inspecting ground preparations. Ridit (relative to an identified distribution) analysis was employed to confirm differences in frequencies of certain quality criteria obtained with various application methods. With regard to degree of obturation and occurrence of porosities, application of temporary fillings with a lentulo spiral or syringe system revealed significantly better results than application with hand instruments (reamer). No differences with regard to degree of obturation were detected when comparing results obtained with syringe or lentulo. Fewer porosities in the apical part of the root canal were seen, both on radiographs and ground sections, with the syringe system compared with the lentulo spiral. In the presence of some contradictory reports found in the literature, the present study suggests that, after straight or slightly curved root canals have been shaped up to at least ISO size 50, high quality temporary root canal fillings may be obtained by application of an aqueous suspension of calcium hydroxide with a syringe system.

  5. The sales learning curve.

    PubMed

    Leslie, Mark; Holloway, Charles A

    2006-01-01

    When a company launches a new product into a new market, the temptation is to immediately ramp up sales force capacity to gain customers as quickly as possible. But hiring a full sales force too early just causes the firm to burn through cash and fail to meet revenue expectations. Before it can sell an innovative product efficiently, the entire organization needs to learn how customers will acquire and use it, a process the authors call the sales learning curve. The concept of a learning curve is well understood in manufacturing. Employees transfer knowledge and experience back and forth between the production line and purchasing, manufacturing, engineering, planning, and operations. The sales learning curve unfolds similarly through the give-and-take between the company--marketing, sales, product support, and product development--and its customers. As customers adopt the product, the firm modifies both the offering and the processes associated with making and selling it. Progress along the manufacturing curve is measured by tracking cost per unit: The more a firm learns about the manufacturing process, the more efficient it becomes, and the lower the unit cost goes. Progress along the sales learning curve is measured in an analogous way: The more a company learns about the sales process, the more efficient it becomes at selling, and the higher the sales yield. As the sales yield increases, the sales learning process unfolds in three distinct phases--initiation, transition, and execution. Each phase requires a different size--and kind--of sales force and represents a different stage in a company's production, marketing, and sales strategies. Adjusting those strategies as the firm progresses along the sales learning curve allows managers to plan resource allocation more accurately, set appropriate expectations, avoid disastrous cash shortfalls, and reduce both the time and money required to turn a profit.

  6. Rehabilitation of concrete canals in urban catchments using low impact development techniques

    NASA Astrophysics Data System (ADS)

    Palanisamy, Bakkiyalakshmi; Chui, Ting Fong May

    2015-04-01

    Urbanization generally increases surface runoff and pollutant loading and decreases infiltration and dry weather flow in canals. Efforts to handle the increased surface runoff, such as widening and deepening canals, further degrade the landscape and riverine habitats. To avert the negative effects of such changes, low-impact development (LID) has been adopted to restore natural flow processes and enhance nutrient removal from urban runoff in recent years. However, the installation of LID techniques often requires space, which can be very limited in intensely developing catchments. This study proposes to install a LID structure, referred to as the Green Channel Cover (GCC), in the space available on top of an open concrete canal to retain stormwater at the receiving end of the water body. The bioretention LID module of the Environmental Protection Agency's Storm Water Management Model 5 was used to simulate flow through the proposed GCC. The peak canal flow depth in a heavily urbanized, tropical catchment was reduced by up to 14% in the presence of the GCC, which occupied only 0.07% of the catchment area. The proposed GCC also retained up to 36 mm of the storm water runoff during peak flows, which resulted in peak flow reduction, especially during high intensity rainfall events with precipitation rates greater than 25 mm h-1. A sensitivity analysis showed that the hydraulic conductivity and depths of the soil and storage layers of the GCC did not influence the peak flow reduction as much as the percent impervious area of the catchment. A partial GCC, with an opening that allows direct sunlight and rainfall into canal, was also successfully tested for efficiency in reducing canal peak flows. Overall, the GCC was found to be a good augmentation to existing rehabilitation measures in urban catchments.

  7. Monitoring Project CANAL Training Activities: Parent Day Workshops for 70 Project CANAL Schools (April 18 through July 3, 1991).

    ERIC Educational Resources Information Center

    Davidson, Mary E.; Kurtz, Norman R.

    An evaluation was done to assess the participation of parents from the 70 Creating a New Approach to Learning Project (Project CANAL) schools in Project CANAL training activities. Project CANAL offered workshops for parents during the months of April and July 1991. The parent day workshops were to provide parents of participating schools with data…

  8. Dynamics of curved interfaces

    SciTech Connect

    Escudero, Carlos

    2009-08-15

    Stochastic growth phenomena on curved interfaces are studied by means of stochastic partial differential equations. These are derived as counterparts of linear planar equations on a curved geometry after a reparametrization invariance principle has been applied. We examine differences and similarities with the classical planar equations. Some characteristic features are the loss of correlation through time and a particular behavior of the average fluctuations. Dependence on the metric is also explored. The diffusive model that propagates correlations ballistically in the planar situation is particularly interesting, as this propagation becomes nonuniversal in the new regime.

  9. Generating artificial light curves: revisited and updated

    NASA Astrophysics Data System (ADS)

    Emmanoulopoulos, D.; McHardy, I. M.; Papadakis, I. E.

    2013-08-01

    The production of artificial light curves with known statistical and variability properties is of great importance in astrophysics. Consolidating the confidence levels during cross-correlation studies, understanding the artefacts induced by sampling irregularities, establishing detection limits for future observatories are just some of the applications of simulated data sets. Currently, the widely used methodology of amplitude and phase randomization is able to produce artificial light curves which have a given underlying power spectral density (PSD) but which are strictly Gaussian distributed. This restriction is a significant limitation, since the majority of the light curves, e.g. active galactic nuclei, X-ray binaries, gamma-ray bursts, show strong deviations from Gaussianity exhibiting `burst-like' events in their light curves yielding long-tailed probability density functions (PDFs). In this study, we propose a simple method which is able to precisely reproduce light curves which match both the PSD and the PDF of either an observed light curve or a theoretical model. The PDF can be representative of either the parent distribution or the actual distribution of the observed data, depending on the study to be conducted for a given source. The final artificial light curves contain all of the statistical and variability properties of the observed source or theoretical model, i.e. the same PDF and PSD, respectively. Within the framework of Reproducible Research, the code and the illustrative example used in this paper are both made publicly available in the form of an interactive MATHEMATICA notebook.

  10. Classification of ASKAP Vast Radio Light Curves

    NASA Technical Reports Server (NTRS)

    Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.

    2012-01-01

    The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.

  11. Graphing Polar Curves

    ERIC Educational Resources Information Center

    Lawes, Jonathan F.

    2013-01-01

    Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…

  12. Textbook Factor Demand Curves.

    ERIC Educational Resources Information Center

    Davis, Joe C.

    1994-01-01

    Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)

  13. Curve Fit Challenge

    ERIC Educational Resources Information Center

    Harper, Suzanne R.; Driskell, Shannon

    2005-01-01

    Graphic tips for using the Geometer's Sketchpad (GSP) are described. The methods to import an image into GSP, define a coordinate system, plot points and curve fit the function using a graphical calculator are demonstrated where the graphic features of GSP allow teachers to expand the use of the technology application beyond the classroom.

  14. The Bacterial Growth Curve.

    ERIC Educational Resources Information Center

    Paulton, Richard J. L.

    1991-01-01

    A procedure that allows students to view an entire bacterial growth curve during a two- to three-hour student laboratory period is described. Observations of the lag phase, logarithmic phase, maximum stationary phase, and phase of decline are possible. A nonpathogenic, marine bacterium is used in the investigation. (KR)

  15. Comparison of the rheological properties of four root canal sealers

    PubMed Central

    Chang, Seok Woo; Lee, Young-Kyu; Zhu, Qiang; Shon, Won Jun; Lee, Woo Cheol; Kum, Kee Yeon; Baek, Seung Ho; Lee, In Bog; Lim, Bum-Soon; Bae, Kwang Shik

    2015-01-01

    The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method (ISO 6876), and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer (Capseal) and three commercial root canal sealers (AH Plus, Sealapex and Pulp Canal Sealer EWT) were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method (n=5) and their viscosities were measured using a strain-controlled rheometer (n=5). The correlation between these two values was statistically analysed using Spearman's correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated (ρ=−0.8618). The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order: AH Pluscanal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers. PMID:25059248

  16. Dorello's Canal for Laymen: A Lego-Like Presentation

    PubMed Central

    Ezer, Haim; Banerjee, Anirban Deep; Thakur, Jai Deep; Nanda, Anil

    2012-01-01

    Objective Dorello's canal was first described by Gruber in 1859, and later by Dorello. Vail also described the anatomy of Dorello's canal. In the preceding century, Dorello's canal was clinically important, in understanding sixth nerve palsy and nowadays it is mostly important for skull base surgery. The understanding of the three dimensional anatomy, of this canal is very difficult to understand, and there is no simple explanation for its anatomy and its relationship with adjacent structures. We present a simple, Lego-like, presentation of Dorello's canal, in a stepwise manner. Materials and Methods Dorello's canal was dissected in five formalin-fixed cadaver specimens (10 sides). The craniotomy was performed, while preserving the neural and vascular structures associated with the canal. A 3D model was created, to explain the canal's anatomy. Results Using the petrous pyramid, the sixth nerve, the cavernous sinus, the trigeminal ganglion, the petorclival ligament and the posterior clinoid, the three-dimensional structure of Dorello's canal was defined. This simple representation aids in understanding the three dimensional relationship of Dorello's canal to its neighboring structures. Conclusion Dorello's canal with its three dimensional structure and relationship to its neighboring anatomical structures could be reconstructed using a few anatomical building blocks. This method simplifies the understanding of this complex anatomical structure, and could be used for teaching purposes for aspiring neurosurgeons, and anatomy students. PMID:23730547

  17. Population reference range for developmental lumbar spinal canal size

    PubMed Central

    Huang, Junbin; Law, Sheung-Wai; Xiao, Fan; Leung, Jason Chi Shun; Wang, Defeng; Shi, Lin

    2016-01-01

    Background Considerable variability exists in normal developmental lumbar spinal canal size. This impacts the likelihood of neural compromise. Spinal canal development is complete by 17 years. As diseases incurred thereafter do not knowingly affect the developmental size of the spinal canal, it is reasonable to use a selected population undergoing abdominopelvic computed tomography (CT) examination to determine developmental lumbar spinal canal size. Methods Study approval was granted by the Clinical Research Ethics Committee. Between Feb 2014 and Jan 2015, mid-vertebral spinal canal cross-sectional area (CSA), depth, width, and vertebral body CSA at each level from L1–L5 was measured, using a semi-automated computerized method in 1,080 ambulatory patients (540 males, 540 females, mean age, 50.5±17 years). Patient height and weight was measured. Results A reference range for developmental lumbar spinal canal dimensions was developed at each lumbar level for each sex. There was a 34% variation in spinal canal CSA between smallest and largest quartiles. Developmental spinal canal CSA and depth were consistently smallest at L3, enlarging cranially and caudally. Taller people had slightly larger lumbar spinal canals (P<0.0001). Males had larger spinal canal CSAs than females though relative to vertebral body CSA, spinal canal CSA was larger in females. There was no change in spinal canal CSA with age, weight or BMI (P<0.05). Conclusions A population reference range for developmental lumbar spinal canal size was developed. This allows one to objectively determine the degree of developmental spinal canal stenosis present on an individual patient basis. PMID:28090445

  18. Water quality of the Boca Raton canal system and effects of the Hillsboro Canal inflow, southeastern Florida, 1990-91

    USGS Publications Warehouse

    McKenzie, D.J.

    1995-01-01

    The City of Boca Raton in southeastern Palm Beach County, Florida, is an urban residential area that has sustained a constant population growth with subsequent increase in water use. The Boca Raton network of canals is controlled to provide for drainage of excess water, to maintain proper coastal ground-water levels to prevent saltwater intrusion, and to recharge the surficial aquifer system from which the city withdraws potable water. Most of the water supplied to the Boca Raton canal system and the surficial aquifer system, other than rainfall and runoff, is pumped from the Hillsboro Canal. The Biscayne aquifer, principal hydrogeologic unit of the surficial aquifer system, is highly permeable and there is a close relation between water levels in the canals and the aquifer. The amount of water supplied by seepage from the conservation areas is unknown. Because the Hillsboro Canal flows from Lake Okeechobee and Water Conservation Areas 1 and 2, which are places of more highly mineralized ground water and surface water, the canal is a possible source of contamination. Water samples were collected at 10 canal sites during wet and dry seasons and analyzed for major inorganic ions and related characteristics, nutrients, and trace elements. All concentrations were generally within or less than the drinking-water standards established by the Florida Department of Environmental Protection. The high concentrations of sodium and chloride that were detected in samples from the Boca Raton canal system are probably from the more mineralized water of the Hillsboro Canal. Other water-quality data, gathered from various sources from 1982 through 1991, did not indicate any significant changes nor trends. The effects of the Hillsboro Canal on the water quality of the Boca Raton canal system are indicated by increased concentrations of sodium, chloride, dissolved solids, and total organic carbon. Concentrations of the constituents in the canal water generally decrease with distance

  19. Trishear for curved faults

    NASA Astrophysics Data System (ADS)

    Brandenburg, J. P.

    2013-08-01

    Fault-propagation folds form an important trapping element in both onshore and offshore fold-thrust belts, and as such benefit from reliable interpretation. Building an accurate geologic interpretation of such structures requires palinspastic restorations, which are made more challenging by the interplay between folding and faulting. Trishear (Erslev, 1991; Allmendinger, 1998) is a useful tool to unravel this relationship kinematically, but is limited by a restriction to planar fault geometries, or at least planar fault segments. Here, new methods are presented for trishear along continuously curved reverse faults defining a flat-ramp transition. In these methods, rotation of the hanging wall above a curved fault is coupled to translation along a horizontal detachment. Including hanging wall rotation allows for investigation of structures with progressive backlimb rotation. Application of the new algorithms are shown for two fault-propagation fold structures: the Turner Valley Anticline in Southwestern Alberta, and the Alpha Structure in the Niger Delta.

  20. Atlas of fatigue curves

    SciTech Connect

    Boyer, H.E.

    1986-01-01

    This Atlas was developed to serve engineers who are looking for fatigue data on a particular metal or alloy. Having these curves compiled in a single book will also facilitate the computerization of the involved data. It is pointed out that plans are under way to make the data in this book available in ASCII files for analysis by computer programs. S-N curves which typify effects of major variables are considered along with low-carbon steels, medium-carbon steels, alloy steels, HSLA steels, high-strength alloy steels, heat-resisting steels, stainless steels, maraging steels, cast irons, and heat-resisting alloys. Attention is also given to aluminum alloys, copper alloys, magnesium alloys, molybdenum, tin alloys, titanium and titanium alloys, zirconium, steel castings, closed-die forgings, powder metallurgy parts, composites, effects of surface treatments, and test results for component parts.

  1. Congenital narrowing of the cervical spinal canal.

    PubMed Central

    Kessler, J T

    1975-01-01

    The clinical and laboratory findings in six patients with congenital narrowing of the cervical spinal canal and neurological symptoms are described. A variable age of onset and an entirely male occurrence were found. Signs and symptoms of spinal cord dysfunction predominated in all but one patient. Symptoms were produced in five patients by increased physical activity alone. Congenital narrowing of the cervical spinal canal may result in cord compression without a history of injury and occasionally without evidence of significant bony degenerative changes. The clinical features may be distinguishable from those found in cervical spondylosis without congenital narrowing. Intermittent claudication of the cervical spinal cord appears to be an important feature of this syndrome. Surgery improved four out of five people. PMID:1219087

  2. Partial atrioventricular canal defect in a dog.

    PubMed

    Santamarina, G; Espino, L; Vila, M; Suarez, M L

    2002-01-01

    A case of a partial atrial canal defect is described in a nine-month-old female English setter. The patient had a large ostium primum atrial septal defect and a concurrent malformation of the mitral valve. Electrocardiographic and radiographic findings were suggestive of marked enlargement of the right heart and pulmonary overcirculation. Definitive diagnosis and assessment of the haemodynamic consequences were made using echocardiography. The magnitude of the left-to-right intracardiac shunt was estimated by measuring the pulmonary to systemic flow ratio (Qp/Qs) from Doppler-derived pulmonary and aortic blood flow. The results of this report suggest that dogs with a partial atrioventricular canal defect and concurrent mild mitral regurgitation may exhibit no clinical signs during the first years of life, even in cases with a Qp/Qs ratio of greater than 2.

  3. Mouse Curve Biometrics

    SciTech Connect

    Schulz, Douglas A.

    2007-10-08

    A biometric system suitable for validating user identity using only mouse movements and no specialized equipment is presented. Mouse curves (mouse movements with little or no pause between them) are individually classied and used to develop classication histograms, which are representative of an individual's typical mouse use. These classication histograms can then be compared to validate identity. This classication approach is suitable for providing continuous identity validation during an entire user session.

  4. In vitro study of effect of solvent on root canal retreatment.

    PubMed

    Oyama, Kazumi Onaga Nagayama; Siqueira, Evandro Luiz; Santos, Marcelo dos

    2002-01-01

    The aim of this study was to assess the effectiveness of five different solvents: xylol, eucalyptol, halothane, chloroform and orange oil on softening gutta-percha in simulated root canals. One drop of solvent was placed into a reservoir made in a simulated canal whose channel was previously instrumented and filled with gutta-percha and N-Rickert sealer. After 5 min, softening was evaluated for each solvent by the penetration of a spreader while applying force with a 442 Instron apparatus to reach a depth of 5 mm. The results were analyzed statistically by the Kruskal-Wallis test. Xylol and orange oil were better in softening gutta-percha than the other solvents. There was no significant difference between xylol and orange oil, but these were statistically different from eucalyptol, halothane and chloroform (p < 0.01).

  5. Effect of two contemporary root canal sealers on root canal dentin microhardness

    PubMed Central

    2017-01-01

    Background Successful root canal treatment depends on proper cleaning, disinfecting and shaping of the root canal space. Pulpless teeth have lower dentin microhardness value compared to that of vital teeth. A material which can cause change in dentin composition may affect the microhardness. Thus the aim of this study was to evaluate and compare the effect of two root canal sealers on dentin microhardness. Material and Methods Forty two single rooted teeth were selected and divided into 3 equal groups; Apexit, iRootSP and control groups (n=14) Each group was then divided into 2 subgroups according to the post evaluation period; 1 week and 2 months (n=7). Root canal procedure was done in the experimental groups and obturation was made using either; Apexit, iRootSP or left unprepared and unobturated in the control group. Roots were sectioned transversely into cervical, middle and apical segments. The three sections of each root were mounted in a plastic chuck with acrylic resin. The coronal dentin surfaces of the root segments werepolished. Microhardness of each section was measured at 500 µm and 1000 µm from the canal lumen. Results Four way-ANOVA revealed that different tested sealer materials, canal third, measuring distance from the pulp and time as independent variables had statistically non significant effect on mean microhardness values (VHN) at p≤0.001. Among iRootSP groups there was a statistically significant difference between iRoot SP at coronal root portion (87.79±17.83) and iRoot SP at apical root portion (76.26±9.33) groups where (p=0.01). IRoot SP at coronal canal third had higher statistically significant mean microhardness value (87.79±17.83) compared to Apexit at coronal third (73.61±13.47) where (p=0.01). Conclusions Root canal sealers do not affect dentin microhardness. Key words:Root canal, dentin, sealers, microhardness, bioceramic. PMID:28149466

  6. A pilot study to assess adductor canal catheter tip migration in a cadaver model.

    PubMed

    Leng, Jody C; Harrison, T Kyle; Miller, Brett; Howard, Steven K; Conroy, Myles; Udani, Ankeet; Shum, Cynthia; Mariano, Edward R

    2015-04-01

    An adductor canal catheter may facilitate early ambulation after total knee arthroplasty, but there is concern over preoperative placement since intraoperative migration of catheters may occur from surgical manipulation and result in ineffective analgesia. We hypothesized that catheter type and subcutaneous tunneling may influence tip migration for preoperatively inserted adductor canal catheters. In a male unembalmed human cadaver, 20 catheter insertion trials were divided randomly into one of four groups: flexible epidural catheter either tunneled or not tunneled; or rigid stimulating catheter either tunneled or not tunneled. Intraoperative patient manipulation was simulated by five range-of-motion exercises of the knee. Distance and length measurements were performed by a blinded regional anesthesiologist. Changes in catheter tip to nerve distance (p = 0.225) and length of catheter within the adductor canal (p = 0.467) were not different between the four groups. Two of five non-tunneled stimulating catheters (40 %) were dislodged compared to 0/5 in all other groups (p = 0.187). A cadaver model may be useful for assessing migration of regional anesthesia catheters; catheter type and subcutaneous tunneling may not affect migration of adductor canal catheters based on this preliminary study. However, future studies involving a larger sample size, actual patients, and other catheter types are warranted.

  7. Bacterial streamers in curved microchannels

    NASA Astrophysics Data System (ADS)

    Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard

    2009-11-01

    Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.

  8. Quantization on Curves

    NASA Astrophysics Data System (ADS)

    Frønsdal, Christian; Kontsevich, Maxim

    2007-02-01

    Deformation quantization on varieties with singularities offers perspectives that are not found on manifolds. The Harrison component of Hochschild cohomology, vanishing on smooth manifolds, reflects information about singularities. The Harrison 2-cochains are symmetric and are interpreted in terms of abelian *-products. This paper begins a study of abelian quantization on plane curves over mathbb{C}, being algebraic varieties of the form {mathbb{C}}^2/R, where R is a polynomial in two variables; that is, abelian deformations of the coordinate algebra mathbb{C}[x,y]/(R). To understand the connection between the singularities of a variety and cohomology we determine the algebraic Hochschild (co)homology and its Barr Gerstenhaber Schack decomposition. Homology is the same for all plane curves mathbb{C}[x,y]/R, but the cohomology depends on the local algebra of the singularity of R at the origin. The Appendix, by Maxim Kontsevich, explains in modern mathematical language a way to calculate Hochschild and Harrison cohomology groups for algebras of functions on singular planar curves etc. based on Koszul resolutions.

  9. Will the Nicaragua Canal connect or divide?

    PubMed

    Gross, Michael

    2014-11-03

    A century after the opening of the Panama Canal, a second inter-oceanic passage is set to be built in Central America, this time in Nicaragua. The ambitious and astronomically expensive project promises to bring economic opportunity to a poor country but it also carries risks to its tropical ecosystems. Will the new waterway ultimately link two oceans or divide a continent? Michael Gross investigates.

  10. Molecular network control through boolean canalization.

    PubMed

    Murrugarra, David; Dimitrova, Elena S

    2015-12-01

    Boolean networks are an important class of computational models for molecular interaction networks. Boolean canalization, a type of hierarchical clustering of the inputs of a Boolean function, has been extensively studied in the context of network modeling where each layer of canalization adds a degree of stability in the dynamics of the network. Recently, dynamic network control approaches have been used for the design of new therapeutic interventions and for other applications such as stem cell reprogramming. This work studies the role of canalization in the control of Boolean molecular networks. It provides a method for identifying the potential edges to control in the wiring diagram of a network for avoiding undesirable state transitions. The method is based on identifying appropriate input-output combinations on undesirable transitions that can be modified using the edges in the wiring diagram of the network. Moreover, a method for estimating the number of changed transitions in the state space of the system as a result of an edge deletion in the wiring diagram is presented. The control methods of this paper were applied to a mutated cell-cycle model and to a p53-mdm2 model to identify potential control targets.

  11. Geometric Observers for Dynamically Evolving Curves

    PubMed Central

    Niethammer, Marc; Vela, Patricio A.; Tannenbaum, Allen

    2009-01-01

    This paper proposes a deterministic observer design for visual tracking based on nonparametric implicit (level-set) curve descriptions. The observer is continuous discrete with continuous-time system dynamics and discrete-time measurements. Its state-space consists of an estimated curve position augmented by additional states (e.g., velocities) associated with every point on the estimated curve. Multiple simulation models are proposed for state prediction. Measurements are performed through standard static segmentation algorithms and optical-flow computations. Special emphasis is given to the geometric formulation of the overall dynamical system. The discrete-time measurements lead to the problem of geometric curve interpolation and the discrete-time filtering of quantities propagated along with the estimated curve. Interpolation and filtering are intimately linked to the correspondence problem between curves. Correspondences are established by a Laplace-equation approach. The proposed scheme is implemented completely implicitly (by Eulerian numerical solutions of transport equations) and thus naturally allows for topological changes and subpixel accuracy on the computational grid. PMID:18421113

  12. EVALUATION OF APICAL DEVIATION IN ROOT CANALS INSTRUMENTED WITH K3 AND ProTaper SYSTEMS

    PubMed Central

    dos Santos, Mariana Diniz Bisi; Marceliano, Marília Fagury; Souza, Patrícia Rodrigues de Almeida Silva E

    2006-01-01

    Objectives: this study evaluated the apical deviation of curved root canals instrumented with K3 and ProTaper systems. Material and methods: twenty root canals of human maxillary and mandibular first molars were employed, which were divided into 2 groups: group A (10 teeth) was instrumented with the K3 system, and group B (10 teeth) with the ProTaper system. Evaluation of deviation was performed by double radiographic exposure. Radiographs were achieved before and after instrumentation, with 0.3-second, thus allowing superimposition of images. Three-dimensional computerized tomograph was performed in 3 specimens in each group, as an additional means to evaluate the apical deviation. Results: were evaluated by the parametric test Student-Newman-Keuls at 5%, which did not reveal significance between groups concerning the apical deviation. The results of computerized tomograph images demonstrated that the larger deviation of the root canal occurred at the distolingual area for both systems. Conclusions: both techniques produced a mild apical deviation. Computerized microtomography was shown to be accurate for experimental endodontics studies. PMID:19089248

  13. A new engine-driven canal preparation system with electronic canal measuring capability.

    PubMed

    Kobayashi, C; Yoshioka, T; Suda, H

    1997-12-01

    A new cordless engine-driven root canal preparation system has been developed that electronically monitors the location of the file tip and the torque applied to the file during all instrumentation procedures. The Root ZX is mounted inside the handpiece to measure the canal length. The engine is driven with a rechargeable battery, and it works more than 40 minutes without a recharge. Nickel-titanium files are used for this preparation system. The file is rotated at 240 to 280 rpms. When the file tip reaches the apical constriction, the revolution of the file can be automatically reversed (Auto-apical-reverse mechanism). If there is too much torque, the rotation is automatically reversed (Auto-torque-reverse mechanism). These automatic functions promise a safer engine preparation of the canal with nickel-titanium files.

  14. Cellinoid shape model for multiple light curves

    NASA Astrophysics Data System (ADS)

    Lu, Xiao-Ping; Ip, Wing-Huen

    2015-04-01

    Extended from the ellipsoid shape, cellinoid shape model consists of eight octants from eight different ellipsoids with the constraint that the adjacent octants have the same semi-axes in common. With the asymmetric shape, cellinoid shape model could be adopted in simulating the irregular shapes of asteroids. In this article, we attempt to apply cellinoid shape model to multiple light curves observed in various geometries and present some techniques to make the whole inverse process more efficient. Finally numerical experiments confirm that cellinoid shape model could derive the physical parameters of asteroids from both of synthetic and real light curves.

  15. Environmental pollution and shipping feasibility of the Nicaragua Canal.

    PubMed

    Chen, Jihong; Zeng, Xin; Deng, Yibing

    2016-12-15

    In recent years, the Nicaraguan government's renewed interest in constructing this interoceanic canal has once again aroused widespread concern, particularly in the global shipping industry. The project's immense ecological risks, coupled with the recent expansions of both the Panama Canal and the Suez Canal, have raised questions among scientists and experts about its viability. Whether the Nicaragua Canal is really feasible for international shipping, given its high marine pollution risks, requires the further study. This paper discusses and analyses the feasibility of the Nicaragua Canal in the context of its environmental impact and value as a shipping service. This paper aims to provide an important information reference to inform strategic decision-making among policymakers and stakeholders. Our research results indicate that the environmental complexity, economic costs and safety risks of building a new transoceanic canal are simply too high to justify the project.

  16. Rotation Curves of Galaxies

    NASA Astrophysics Data System (ADS)

    Kalnajs, Agris J.

    One can obtain a fairly good understanding of the relation between axially symmetric mass distributions and the rotation curves they produce without resorting to calculations. However it does require a break with tradition. The first step consists of replacing quantities such as surface density, volume density, and circular velocity with the mass in a ring, mass in a spherical shell, and the square of the circular velocity, or more precisely with 2 pi G r mu(r), 4 pi G r^2 rho(r), and Vc^2 (r). These three quantities all have the same dimensions, and are related to each other by scale-free linear operators. The second step consists of introducing ln(r) as the coordinate. On the log scale the scale-free operators becomes the more familiar convolution operations. Convolutions are easily handled by Fourier techniques and a surface density can be converted into a rotation curve or volume density in a small fraction of a second. A simple plot of 2 pi G r mu(r) as a function of ln(r) reveals the relative contributions of different radii to Vc^2(r). Such a plot also constitutes a sanity test for the fitting of various laws to photometric data. There are numerous examples in the literature of excellent fits to the tails that lack data or are poor fits around the maximum of 2 pi G r mu(r). I will discuss some exact relations between the above three quantities as well as some empirical observations such as the near equality of the maxima of 2 pi G r mu(r) and Vc^2 (r) curves for flat mass distributions.

  17. Curved PVDF airborne transducer.

    PubMed

    Wang, H; Toda, M

    1999-01-01

    In the application of airborne ultrasonic ranging measurement, a partially cylindrical (curved) PVDF transducer can effectively couple ultrasound into the air and generate strong sound pressure. Because of its geometrical features, the ultrasound beam angles of a curved PVDF transducer can be unsymmetrical (i.e., broad horizontally and narrow vertically). This feature is desired in some applications. In this work, a curved PVDF air transducer is investigated both theoretically and experimentally. Two resonances were observed in this transducer. They are length extensional mode and flexural bending mode. Surface vibration profiles of these two modes were measured by a laser vibrometer. It was found from the experiment that the surface vibration was not uniform along the curvature direction for both vibration modes. Theoretical calculations based on a model developed in this work confirmed the experimental results. Two displacement peaks were found in the piezoelectric active direction of PVDF film for the length extensional mode; three peaks were found for the flexural bending mode. The observed peak positions were in good agreement with the calculation results. Transient surface displacement measurements revealed that vibration peaks were in phase for the length extensional mode and out of phase for the flexural bending mode. Therefore, the length extensional mode can generate a stronger ultrasound wave than the flexural bending mode. The resonance frequencies and vibration amplitudes of the two modes strongly depend on the structure parameters as well as the material properties. For the transducer design, the theoretical model developed in this work can be used to optimize the ultrasound performance.

  18. Magnetism in curved geometries

    NASA Astrophysics Data System (ADS)

    Streubel, Robert; Fischer, Peter; Kronast, Florian; Kravchuk, Volodymyr P.; Sheka, Denis D.; Gaididei, Yuri; Schmidt, Oliver G.; Makarov, Denys

    2016-09-01

    Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii-Moriya-like interaction. As a consequence, a family of novel curvature-driven effects emerges, which includes magnetochiral effects and topologically induced magnetization patterning, resulting in theoretically predicted unlimited domain wall velocities, chirality symmetry breaking and Cherenkov-like effects for magnons. The broad range of altered physical properties makes these curved architectures appealing in view of fundamental research on e.g. skyrmionic systems, magnonic crystals or exotic spin configurations. In addition to these rich physics, the application potential of three-dimensionally shaped objects is currently being explored as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices. These recent developments ranging from theoretical predictions over fabrication of three-dimensionally curved magnetic thin films, hollow cylinders or wires, to their characterization using integral means as well as the development of advanced tomography approaches are in the focus of this review.

  19. Magnetism in curved geometries

    SciTech Connect

    Streubel, Robert; Fischer, Peter; Kronast, Florian; Kravchuk, Volodymyr P.; Sheka, Denis D.; Gaididei, Yuri; Schmidt, Oliver G.; Makarov, Denys

    2016-08-17

    Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii–Moriya-like interaction. As a consequence, a family of novel curvature-driven effects emerges, which includes magnetochiral effects and topologically induced magnetization patterning, resulting in theoretically predicted unlimited domain wall velocities, chirality symmetry breaking and Cherenkov-like effects for magnons. The broad range of altered physical properties makes these curved architectures appealing in view of fundamental research on e.g. skyrmionic systems, magnonic crystals or exotic spin configurations. In addition to these rich physics, the application potential of three-dimensionally shaped objects is currently being explored as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices. Finally, these recent developments ranging from theoretical predictions over fabrication of three-dimensionally curved magnetic thin films, hollow cylinders or wires, to their characterization using integral means as well as the development of advanced tomography approaches are in the focus of this review.

  20. Magnetism in curved geometries

    DOE PAGES

    Streubel, Robert; Fischer, Peter; Kronast, Florian; ...

    2016-08-17

    Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii–Moriya-like interaction. Asmore » a consequence, a family of novel curvature-driven effects emerges, which includes magnetochiral effects and topologically induced magnetization patterning, resulting in theoretically predicted unlimited domain wall velocities, chirality symmetry breaking and Cherenkov-like effects for magnons. The broad range of altered physical properties makes these curved architectures appealing in view of fundamental research on e.g. skyrmionic systems, magnonic crystals or exotic spin configurations. In addition to these rich physics, the application potential of three-dimensionally shaped objects is currently being explored as magnetic field sensorics for magnetofluidic applications, spin-wave filters, advanced magneto-encephalography devices for diagnosis of epilepsy or for energy-efficient racetrack memory devices. Finally, these recent developments ranging from theoretical predictions over fabrication of three-dimensionally curved magnetic thin films, hollow cylinders or wires, to their characterization using integral means as well as the development of advanced tomography approaches are in the focus of this review.« less

  1. Complementary Curves of Descent

    DTIC Science & Technology

    2012-11-16

    provision of law , no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid...curves of descent 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) US Naval Academy,Physics Department,Annapolis,MD,21402-1363 8. PERFORMING ORGANIZATION

  2. Curved cap corrugated sheet

    NASA Technical Reports Server (NTRS)

    Davis, R. C.; Bales, T. T.; Royster, D. M.; Jackson, L. R. (Inventor)

    1984-01-01

    The report describes a structure for a strong, lightweight corrugated sheet. The sheet is planar or curved and includes a plurality of corrugation segments, each segment being comprised of a generally U-shaped corrugation with a part-cylindrical crown and cap strip, and straight side walls and with secondary corrugations oriented at right angles to said side walls. The cap strip is bonded to the crown and the longitudinal edge of said cap strip extends beyond edge at the intersection between said crown and said side walls. The high strength relative to weight of the structure makes it desirable for use in aircraft or spacecraft.

  3. 9. EAST SIDE CANAL Photographic copy of historic photo, ...

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

    9. EAST SIDE CANAL - Photographic copy of historic photo, September 17, 1940 (original print in '1940 Annual Report of the Carlsbad Project,' located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) photographer unknown 'CCC ENROLLEES STARTING EXCAVATION FOR ROCK LINING DOWNSTREAM FROM STA. 22. EAST CANAL, LAT. #8' - Carlsbad Irrigation District, East Side Canal, 1 mile North to 2 miles East of Carlsbad, Carlsbad, Eddy County, NM

  4. 10. EAST SIDE CANAL Photographic copy of historic photo, ...

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

    10. EAST SIDE CANAL - Photographic copy of historic photo, December 3, 1940 (original print in '1940 Annual Report of the Carlsbad Project,' located at the Carlsbad Irrigation District offices, Carlsbad, New Mexico) photographer unknown 'LOOKING DOWN FROM STA. #22 LATERAL #8, EAST CANAL. AFTER CCC ENROLLEES FINISHED ROCK LINING' - Carlsbad Irrigation District, East Side Canal, 1 mile North to 2 miles East of Carlsbad, Carlsbad, Eddy County, NM

  5. PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL STA. ...

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

    PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL - STA. 132+82.15. TEXAS HILL CANAL AND DISTRIBUTION SYSTEM. United States Department of Interior, Bureau of Reclamation; Gila Project, Arizona, Wellton-Mohawk Division. Drawing No. 50-D-3200, dated February 7, 1955, Denver, Colorado - Wellton-Mohawk Irrigation System, Relift Station, Texas Hill Canal 2.5, Northern Terminus of Avenue 51 East, approximately .5 mile south of Union Pacific Railroad, Wellton, Yuma County, AZ

  6. GENERAL PLANS AND SECTIONS. WASTEWAY NO. 1. WELLTONMOHAWK CANAL ...

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

    GENERAL PLANS AND SECTIONS. WASTEWAY NO. 1. WELLTON-MOHAWK CANAL - STA. 99+23.50. United States Department of the Interior, Bureau of Reclamation; Gila Project, Arizona, Wellton-Mohawk Division. Drawing No. 50-D-2422, dated January 19, 1949, Denver Colorado - Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal, North side of Wellton-Mohawk Canal, bounded by Gila River to North & the Union Pacific Railroad & Gila Mountains to south, Wellton, Yuma County, AZ

  7. Magnetic resonance imaging of the internal auditory canal

    SciTech Connect

    Daniels, D.L.; Herfkins, R.; Koehler, P.R.; Millen, S.J.; Shaffer, K.A.; Williams, A.L.; Haughton, V.M.

    1984-04-01

    Three patients with exclusively or predominantly intracanalicular neuromas and 5 with presumably normal internal auditory canals were examined with prototype 1.4- or 1.5-tesla magnetic resonance (MR) scanners. MR images showed the 7th and 8th cranial nerves in the internal auditory canal. The intracanalicular neuromas had larger diameter and slightly greater signal strength than the nerves. Early results suggest that minimal enlargement of the nerves can be detected even in the internal auditory canal.

  8. 82. CANAL WEST OF LOCK 12 EAST NEAR BOONTON. STORAGE ...

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

    82. CANAL WEST OF LOCK 12 EAST NEAR BOONTON. STORAGE BUILDING AND CHUTE ON LEFT SIDE OF CANAL MAY BE A COAL FACILITY. COAL WOULD BE UNLOADED FROM THE BOAT AND PASSED UP THE CHUTE INTO THE COAL STORAGE BIN. COAL COULD THEN BE LOADED INTO WAGONS FROM THE BOTTOM OF THE BIN ON THE OPPOSITE SIDE OF THE STRUCTURE WHEN NECESSARY. - Morris Canal, Phillipsburg, Warren County, NJ

  9. Transforming Curves into Curves with the Same Shape.

    ERIC Educational Resources Information Center

    Levine, Michael V.

    Curves are considered to have the same shape when they are related by a similarity transformation of a certain kind. This paper extends earlier work on parallel curves to curves with the same shape. Some examples are given more or less explicitly. A generalization is used to show that the theory is ordinal and to show how the theory may be applied…

  10. 12. VIEW OF WESTERN CANAL AT ALMA SCHOOL ROAD IN ...

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

    12. VIEW OF WESTERN CANAL AT ALMA SCHOOL ROAD IN MESA, THE LOCATION AT WHICH THE PECK, PINE AND WALLACE FEEDERS FORMERLY JOINED TO FORM THE WESTERN CANAL. THE PECK AND PINE FEEDERS, NOW KNOWN AS LATERAL 9 AND LATERAL 10, AND ALMOST ENTIRELY PIPED, STILL JOIN THE WESTERN CANAL AT THIS POINT, BUT AN EQUALLY IMPORTANT SOURCE OF SUPPLY IS THE NUMEROUS GROUNDWATER PUMPS LOCATED ON THE SYSTEM. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

  11. Inverse solution of ear-canal area function from reflectance.

    PubMed

    Rasetshwane, Daniel M; Neely, Stephen T

    2011-12-01

    A number of acoustical applications require the transformation of acoustical quantities, such as impedance and pressure that are measured at the entrance of the ear canal, to quantities at the eardrum. This transformation often requires knowledge of the shape of the ear canal. Previous attempts to measure ear-canal area functions were either invasive, non-reproducible, or could only measure the area function up to a point mid-way along the canal. A method to determine the area function of the ear canal from measurements of acoustic impedance at the entrance of the ear canal is described. The method is based on a solution to the inverse problem in which measurements of impedance are used to calculate reflectance, which is then used to determine the area function of the canal. The mean ear-canal area function determined using this method is similar to mean ear-canal area functions measured by other researchers using different techniques. The advantage of the proposed method over previous methods is that it is non- invasive, fast, and reproducible.

  12. GeoGebra helps to know canal surfaces better

    NASA Astrophysics Data System (ADS)

    Bímová, Daniela; Bittnerová, Daniela; Vraštil, Ondřej

    2015-11-01

    GeoGebra 5.0 is the dynamic geometric and mathematic software which dynamic tools allow the user to solve dynamic problems in a plane and as well as in the three-dimensional space. The contribution presents the dynamic applets constructed in GeoGebra 5.0 that show the origin as well as some properties of various kinds of canal surfaces. There are described the applets for constructing the canal surfaces in the paper. Some of the created canal surfaces are compared with the real life canal surface examples.

  13. MAXILLARY FIRST PREMOLAR WITH THREE ROOT CANALS: A CASE REPORT

    PubMed Central

    Sulaiman, A.O; Dosumu, O.O; Amedari, McKing

    2013-01-01

    The maxillary first premolar is the most commonly bi- rooted tooth with occasional presentation of three roots system; it is a transitional tooth between incisors and molars. Although it usually has two canals, it may rarely have three and this third canal can easily be missed. Thus meticulous knowledge of tooth morphology, careful interpretation of angled radiographs, proper access cavity preparation and a detailed exploration of the interior of the tooth is needed to ensure a proper endodontic treatment. This article reports a rare finding of three canals in a maxillary first premolar with non well defined root outline radiographically during an elective root canal treatment. PMID:25161429

  14. Wind Simulation

    SciTech Connect

    Walker, Howard Andrew

    2008-12-31

    The Software consists of a spreadsheet written in Microsoft Excel that provides an hourly simulation of a wind energy system, which includes a calculation of wind turbine output as a power-curve fit of wind speed.

  15. Mapping curved spacetimes into Dirac spinors

    PubMed Central

    Sabín, Carlos

    2017-01-01

    We show how to transform a Dirac equation in a curved static spacetime into a Dirac equation in flat spacetime. In particular, we show that any solution of the free massless Dirac equation in a 1 + 1 dimensional flat spacetime can be transformed via a local phase transformation into a solution of the corresponding Dirac equation in a curved static background, where the spacetime metric is encoded into the phase. In this way, the existing quantum simulators of the Dirac equation can naturally incorporate curved static spacetimes. As a first example we use our technique to obtain solutions of the Dirac equation in a particular family of interesting spacetimes in 1 + 1 dimensions. PMID:28074908

  16. Mapping curved spacetimes into Dirac spinors.

    PubMed

    Sabín, Carlos

    2017-01-11

    We show how to transform a Dirac equation in a curved static spacetime into a Dirac equation in flat spacetime. In particular, we show that any solution of the free massless Dirac equation in a 1 + 1 dimensional flat spacetime can be transformed via a local phase transformation into a solution of the corresponding Dirac equation in a curved static background, where the spacetime metric is encoded into the phase. In this way, the existing quantum simulators of the Dirac equation can naturally incorporate curved static spacetimes. As a first example we use our technique to obtain solutions of the Dirac equation in a particular family of interesting spacetimes in 1 + 1 dimensions.

  17. Geometric Mechanics of Curved Crease Origami

    NASA Astrophysics Data System (ADS)

    Dias, Marcelo A.; Dudte, Levi H.; Mahadevan, L.; Santangelo, Christian D.

    2012-09-01

    Folding a sheet of paper along a curve can lead to structures seen in decorative art and utilitarian packing boxes. Here we present a theory for the simplest such structure: an annular circular strip that is folded along a central circular curve to form a three-dimensional buckled structure driven by geometrical frustration. We quantify this shape in terms of the radius of the circle, the dihedral angle of the fold, and the mechanical properties of the sheet of paper and the fold itself. When the sheet is isometrically deformed everywhere except along the fold itself, stiff folds result in creases with constant curvature and oscillatory torsion. However, relatively softer folds inherit the broken symmetry of the buckled shape with oscillatory curvature and torsion. Our asymptotic analysis of the isometrically deformed state is corroborated by numerical simulations that allow us to generalize our analysis to study structures with multiple curved creases.

  18. Geometric mechanics of curved crease origami.

    PubMed

    Dias, Marcelo A; Dudte, Levi H; Mahadevan, L; Santangelo, Christian D

    2012-09-14

    Folding a sheet of paper along a curve can lead to structures seen in decorative art and utilitarian packing boxes. Here we present a theory for the simplest such structure: an annular circular strip that is folded along a central circular curve to form a three-dimensional buckled structure driven by geometrical frustration. We quantify this shape in terms of the radius of the circle, the dihedral angle of the fold, and the mechanical properties of the sheet of paper and the fold itself. When the sheet is isometrically deformed everywhere except along the fold itself, stiff folds result in creases with constant curvature and oscillatory torsion. However, relatively softer folds inherit the broken symmetry of the buckled shape with oscillatory curvature and torsion. Our asymptotic analysis of the isometrically deformed state is corroborated by numerical simulations that allow us to generalize our analysis to study structures with multiple curved creases.

  19. The Characteristic Curves of Water

    NASA Astrophysics Data System (ADS)

    Neumaier, Arnold; Deiters, Ulrich K.

    2016-09-01

    In 1960, E. H. Brown defined a set of characteristic curves (also known as ideal curves) of pure fluids, along which some thermodynamic properties match those of an ideal gas. These curves are used for testing the extrapolation behaviour of equations of state. This work is revisited, and an elegant representation of the first-order characteristic curves as level curves of a master function is proposed. It is shown that Brown's postulate—that these curves are unique and dome-shaped in a double-logarithmic p, T representation—may fail for fluids exhibiting a density anomaly. A careful study of the Amagat curve (Joule inversion curve) generated from the IAPWS-95 reference equation of state for water reveals the existence of an additional branch.

  20. Cancer Incidence among Former Love Canal Residents

    PubMed Central

    Gensburg, Lenore J.; Pantea, Cristian; Kielb, Christine; Fitzgerald, Edward; Stark, Alice; Kim, Nancy

    2009-01-01

    Background The Love Canal was a rectangular 16-acre, 10-ft-deep chemical waste landfill situated in a residential neighborhood in Niagara Falls, New York. This seriously contaminated site came to public attention in 1978. Only one prior study examined cancer incidence in former residents of the Love Canal neighborhood (LC). Objective In this study we aimed to describe cancer incidence in former LC residents from 1979 to 1996 and to investigate whether it differs from that of New York State (NYS) and Niagara County (NC). Methods From 1978 to 1982, we interviewed 6,181 former residents, and 5,052 were eligible to be included in this study. In 1996, we identified 304 cancer diagnoses in this cohort using the NYS Cancer Registry. We compared LC cancer incidence with that of NYS and NC using standardized incidence ratios (SIRs), and we compared risks within the LC group by potential exposure to the landfill using survival analysis. Results SIRs were elevated for cancers of the bladder [SIRNYS = 1.44; 95% confidence interval (CI), 0.91–2.16] and kidney (SIRNYS = 1.48; 95% CI, 0.76–2.58). Although CIs included 1.00, other studies have linked these cancers to chemicals similar to those found at Love Canal. We also found higher rates of bladder cancer among residents exposed as children, based on two cases. Conclusions In explaining these excess risks, the role of exposure to the landfill is unclear given such limitations as a relatively small and incomplete study cohort, imprecise exposure measurements, and the exclusion of cancers diagnosed before 1979. Given the relatively young age of the cohort, further surveillance is warranted. PMID:19672407

  1. Multiple CubicBezier Curves.

    ERIC Educational Resources Information Center

    Khonsari, Michael M.; Horn, Douglas

    1990-01-01

    An algorithm is described for generating smooth curves of first-order continuity. The algorithm is composed of several cubic Bezier curves joined together at the user defined control points. Introduced is a tension control parameter which can be set thus providing additional flexibility in the design of free-form curves. (KR)

  2. Titration Curves: Fact and Fiction.

    ERIC Educational Resources Information Center

    Chamberlain, John

    1997-01-01

    Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…

  3. Assessment of trace metal contamination in a historical freshwater canal (Buckingham Canal), Chennai, India.

    PubMed

    Jayaprakash, M; Nagarajan, R; Velmurugan, P M; Sathiyamoorthy, J; Krishnamurthy, R R; Urban, B

    2012-12-01

    The present study was done to assess the sources and the major processes controlling the trace metal distribution in sediments of Buckingham Canal. Based on the observed geochemical variations, the sediments are grouped as South Buckingham Canal and North Buckingham Canal sediments (SBC and NBC, respectively). SBC sediments show enrichment in Fe, Ti, Mn, Cr, V, Mo, and As concentrations, while NBC sediments show enrichment in Sn, Cu, Pb, Zn, Ni, and Hg. The calculated Chemical Index of Alteration and Chemical Index of Weathering values for all the sediments are relatively higher than the North American Shale Composite and Upper Continental Crust but similar to Post-Archaean Average Shale, and suggest a source area with moderate weathering. Overall, SBC sediments are highly enriched in Mo, Zn, Cu, and Hg (geoaccumulation index (I(geo)) class 4-6), whereas NBC sediments are enriched in Sn, Cu, Zn, and Hg (I(geo) class 4-6). Cu, Ni, and Cr show higher than Effects-Range Median values and hence the biological adverse effect of these metals is 20%; Zn, which accounts for 50%, in the NBC sediments, has a more biological adverse effect than other metals found in these sediments. The calculated I(geo), Enrichment Factor, and Contamination Factor values indicate that Mo, Hg, Sn, Cu, and Zn are highly enriched in the Buckingham Canal sediments, suggesting the rapid urban and industrial development of Chennai Metropolitan City have negatively influenced on the surrounding aquatic ecosystem.

  4. Canalers and Conservationists: The Projected Cross-Florida Canal. Instructional Activities Series IA/S-8.

    ERIC Educational Resources Information Center

    Fernald, Edward A.

    This activity is one of a series of 17 teacher-developed instructional activities for geography at the secondary-grade level described in SO 009 140. This activity investigates environmental quality employing the problem-solving technique. Using a map which shows the proposed route of the cross-Florida barge canal as a focal point, the teacher…

  5. Large small cell carcinoma of anorectal canal.

    PubMed

    Ghahramani, Leila; Mohammadianpanah, Mohammad; Hosseini, Seyed Vahid; Hosseinzade, Masood; Izadpanah, Ahmad; Ebrahimian, Saba; Bananzadeh, Alimohammad

    2014-03-01

    Neurofibromatosis type-1 (NF1), also known as Von Recklinghausen disease, is an autosomal dominant disorder with incidence of one per 4000. Neurofibromas are benign, heterogeneous, peripheral nerve sheath tumors coming up from the connective tissue of peripheral nerve sheaths, particularly the endoneurium. Visceral involvement in disseminated neurofibromatosis is considered rare. Neurofibroma occurs most frequently in the stomach and jejunum, but colon and anorectal canal may also be involved. Gastrointestinal neurofibromas may lead to bleeding, obstruction, intussusception, protein-losing enteropathy and bowel perforation. We encountered a case of diffusely involving the anorectal area by huge neurofibroma, which resulted in pelvic pain with watery diarrhea and urgency.

  6. [Frey's syndrome of the external auditory canal].

    PubMed

    Constantinidis, J; Kyriafinis, G; Ereliadis, S; Daniilidis, J

    2004-10-01

    Frey's syndrome of the external auditory canal is extremely rare. A 55-year old woman presented with a 6 month history of unilateral gustatory otorrhea. She never complained of hearing impairment, tinnitus, vertigo or otalgia. No trauma or surgical signs were evident near the ear or parotid gland. Examination of the ear showed an intact tympanic membrane without disease. A diagnosis of gustatory sweating syndrome was suggested by the observation of sweat production after chewing and by Minor's starch-iodine test. Symptoms were relieved after tympanic neurectomy. The pathogenesis, differential diagnosis and treatment options are discussed.

  7. Cancer incidence in the Love Canal area

    SciTech Connect

    Janerich, D.T.; Burnett, W.S.; Feck, G.; Hoff, M.; Nasca, P.; Polednak, A.P.; Greenwald, P.; Vianna, N.

    1981-06-01

    Data from the New York Cancer Registry show no evidence for higher cancer rates associated with residence near the Love Canal toxic waste burial site in comparison with the entire state outside of New York City. Rates of liver cancer, lymphoma, and leukemia, which were selected for special attention, were not consistently elevated. Among the other cancers studied, a higher rate was noted only for respiratory cancer, but it was not consistent across age groups and appeared to be related to a high rate for the entire city of Niagara Falls. There was no evidence that the lung cancer rate was associated with the toxic wastes buried at the dump site.

  8. Cancer incidence in the Love Canal area.

    PubMed

    Janerich, D T; Burnett, W S; Feck, G; Hoff, M; Nasca, P; Polednak, A P; Greenwald, P; Vianna, N

    1981-06-19

    Data from the New York Cancer Registry show no evidence for higher cancer rates associated with residence near the Love Canal toxic waste burial site in comparison with the entire state outside of New York City. Rates of liver cancer, lymphoma, and leukemia, which were selected for special attention, were not consistently elevated. Among the other cancers studied, a higher rate was noted only for respiratory cancer, but it was not consistent across age groups and appeared to be related to a high rate for the entire city of Niagara Falls. There was no evidence that the lung cancer rate was associated with the toxic wastes buried at the dump site.

  9. Suez Canal Clearance Operation, Task Force 65

    DTIC Science & Technology

    1975-05-01

    and remove the four wrecks from the central region of the canal; DREDGE 23, Tug MONGUED, Dredge KASSER and a Concrete Caisson. All salvage operations...feet BUCKET DREDGE NO. 23 72.00 1600 tons 191 feet TUG MONGUED 81.50 1200 tons 165 feet DIPPER DREDGE KASSER 81.50 1200 tons 125 feet CONCRETE CAISSON...MONGUED, DREDGE KASSER , and DREDGE 23 to wet dump in the Great Bitter Lake. Heavy crane THOR arrived in Port Said after transit from Hamburg, Germany

  10. Quantum relative Lorenz curves

    NASA Astrophysics Data System (ADS)

    Buscemi, Francesco; Gour, Gilad

    2017-01-01

    The theory of majorization and its variants, including thermomajorization, have been found to play a central role in the formulation of many physical resource theories, ranging from entanglement theory to quantum thermodynamics. Here we formulate the framework of quantum relative Lorenz curves, and show how it is able to unify majorization, thermomajorization, and their noncommutative analogs. In doing so, we define the family of Hilbert α divergences and show how it relates with other divergences used in quantum information theory. We then apply these tools to the problem of deciding the existence of a suitable transformation from an initial pair of quantum states to a final one, focusing in particular on applications to the resource theory of athermality, a precursor of quantum thermodynamics.

  11. Multipulse phase resetting curves

    NASA Astrophysics Data System (ADS)

    Krishnan, Giri P.; Bazhenov, Maxim; Pikovsky, Arkady

    2013-10-01

    In this paper, we introduce and study systematically, in terms of phase response curves, the effect of dual-pulse excitation on the dynamics of an autonomous oscillator. Specifically, we test the deviations from linear summation of phase advances resulting from two small perturbations. We analytically derive a correction term, which generally appears for oscillators whose intrinsic dimensionality is >1. The nonlinear correction term is found to be proportional to the square of the perturbation. We demonstrate this effect in the Stuart-Landau model and in various higher dimensional neuronal models. This deviation from the superposition principle needs to be taken into account in studies of networks of pulse-coupled oscillators. Further, this deviation could be used in the verification of oscillator models via a dual-pulse excitation.

  12. Roles of the combined irrigation, drainage, and storage of the canal network in improving water reuse in the irrigation districts along the lower Yellow River, China

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Luo, Yi; He, Chansheng; Lai, Jianbin; Li, Xiubin

    2010-09-01

    SummaryThe commonly used irrigation system in the irrigation districts (with a combined irrigation area of 3.334 × 10 6 ha) along the lower Yellow River of China is canal network. It delivers water from the Yellow River to the fields, collects surface runoff and drainage from cropland, and stores both of them for subsequent irrigation uses. This paper developed a new combined irrigation, drainage, and storage (CIDS) module for the SWAT2000 model, simulated the multiple roles of the CIDS canal system, and estimated its performance in improving water reuse in the irrigation districts under different irrigation and water diversion scenarios. The simulation results show that the annual evapotranspiration (ET) of the double-cropping winter wheat and summer maize was the highest under the full irrigation scenario (automatic irrigation), and the lowest under the no irrigation scenario. It varied between these two values when different irrigation schedules were adopted. Precipitation could only meet the water requirement of the double-cropping system by 62-96% on an annual basis; that of the winter wheat by 32-36%, summer maize by 92-123%, and cotton by 87-98% on a seasonal basis. Hence, effective irrigation management for winter wheat is critical to ensure high wheat yield in the study area. Runoff generation was closely related to precipitation and influenced by irrigation. The highest and lowest annual runoff accounted for 19% and 11% of the annual precipitation under the full irrigation and no irrigation scenarios, respectively. Nearly 70% of the annual runoff occurred during months of July and August due to the concentrated precipitation in these 2 months. The CIDS canals play an important role in delivering the diversion water from the Yellow River, intercepting the surface runoff and drainage from cropland (inflow of the CIDS canal) and recharging the shallow aquifer for later use. Roughly 14-26% of the simulated total flow in the CIDS canal system recharged

  13. Water Environment Evolution along the China Grand Canal

    NASA Astrophysics Data System (ADS)

    Mao, F.; Wu, Y. X.; Yang, B. F.; Li, X. J.

    2014-03-01

    The China Grand Canal is one of the earliest canals in the world, having lasted for nearly 3000 years. Even its section canals have a rich history, such as the North-South Grand Canal that was established during the Sui Dynasty, whereas the Beijing-Hangzhou Canal was excavated during the Yuan Dynasty and the east line of the South-to-North Water Diversion. As one of the longest in the world, the China Grand Canal's total length is over 3500 kilometers. This length includes the navigable, unnavigable, and underground sections. Making the best use of situations and according to local conditions, the Chinese people harmoniously constructed the Beijing-Hangzhou Canal with nature. Tens of millions of workers took nearly 3000 years to complete the great shipping system. Navigable sections still exist for up to 900 kilometers and the volume of freight traffic is approximately 300 million tons. The canal remains the main logistical channel of the North-to-South Coal Transportation, South-to-North Water Diversion, and resources circulation. To date, China is promoting the success of heritage application. Part of these efforts is the declaration of the China Grand Canal as a World Cultural Heritage by 2014. In addition, the east route of the South-to-North Water Transfer project is planned to be navigable by 2016. The ancient Beijing-Hangzhou Grand Canal will usher in the new ecological civilization and cultural revival along the canal. This paper presents technical methods of water environment evolution research on the river system, river, and water quality along the Beijing-Hangzhou Canal through the integration of historical literature and modern remote sensing image data. The study carried out water environment investigation and analysis along the Beijing-Hangzhou canal by using ETM, SPOT image data, and GPS measurement data. Spatial and temporal evolution characteristics and regulations of the Beijing-Hangzhou Grand Canal regional water environment in the span of 3000

  14. Root canal filling evaluation using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Negrutiu, Meda L.; Sinescu, Cosmin; Topala, Florin; Nica, Luminita; Ionita, Ciprian; Marcauteanu, Corina; Goguta, Luciana; Bradu, Adrian; Dobre, George; Rominu, Mihai; Podoleanu, Adrian Gh.

    2010-04-01

    Endodontic therapy consists in cleaning and shaping the root canal system, removing organic debris and sealing the intra-canal space with permanent filling materials. The purpose of this study was to evaluate various root canal fillings in order to detect material defects, the marginal adaptation at the root canal walls and to assess the quality of the apical sealing. 21 extracted single-root canal human teeth were selected for this study. We instrumented all roots using NiTi rotary instruments. All canals were enlarged with a 6% taper size 30 GT instrument, 0,5 mm from the anatomical apex. The root canals were irrigated with 5% sodium hypochlorite, followed by 17% ethylenediaminetetraacetic acid (EDTA). After the instrumentation was completed, the root canals were obturated using a thermoplasticizable polymer of polyesters. In order to assess the defects inside the filling material and the marginal fit to the root canal walls, the conebeam micro-computed tomography (CBμCT) was used first. After the CBμCT investigation, time domain optical coherence tomography working in en face mode (TDefOCT) was employed to evaluate the previous samples. The TDefOCT system was working at 1300 nm and was doubled by a confocal channel at 970 nm. The results obtained by CBμCT revealed no visible defects inside the root-canal fillings and at the interfaces with the root-canal walls. TDefOCT investigations permit to visualize a more complex stratificated structure at the interface filling material/dental hard tissue and in the apical region.

  15. The Strength-Interval Curve in Cardiac Tissue

    PubMed Central

    Kandel, Sunil M.; Roth, Bradley J.

    2013-01-01

    The bidomain model describes the electrical properties of cardiac tissue and is often used to simulate the response of the heart to an electric shock. The strength-interval curve summarizes how refractory tissue is excited. This paper analyzes calculations of the strength-interval curve when a stimulus is applied through a unipolar electrode. In particular, the bidomain model is used to clarify why the cathodal and anodal strength-interval curves are different, and what the mechanism of the “dip” in the anodal strength-interval curve is. PMID:23509598

  16. Automated reasoning about cubic curves.

    SciTech Connect

    Padmanabhan, R.; McCune, W.; Mathematics and Computer Science; Univ. of Manitoba

    1995-01-01

    It is well known that the n-ary morphisms defined on projective algebraic curves satisfy some strong local-to-global equational rules of derivation not satisfied in general by universal algebras. For example, every rationally defined group law on a cubic curve must be commutative. Here we extract from the geometry of curves a first order property (gL) satisfied by all morphisms defined on these curves such that the equational consequences known for projective curves can be derived automatically from a set of six rules (stated within the first-order logic with equality). First, the rule (gL) is implemented in the theorem-proving program Otter. Then we use Otter to automatically prove some incidence theorems on projective curves without any further reference to the underlying geometry or topology of the curves.

  17. Update on Schlemm's Canal Based Procedures

    PubMed Central

    Mansouri, Kaweh; Shaarawy, Tarek

    2015-01-01

    Surgical options for glaucoma have expanded in recent years. This article provides an evidence-based update on the novel or emerging surgical techniques for the treatment of open-angle glaucoma that are based on the Schlemm's canal (SC). Canaloplasty is an ab externo approach and was developed as an alternative to traditional filtering surgeries. The Hydrus microstent (Ivantis Inc., Irvine, CA) is a so-called SC scaffold that directly bypasses the trabecular meshwork to drain aqueous humor into the SC, which it keeps dilated over approximately one quadrant. Canaloplasty has also been shown to lower intraocular pressure (IOP) by up to 40% and combined with cataract surgery. IOP was lowered 44% at 24 months while maintaining a favorable safety profile. The Hydrus device has been proposed as an adjunct to cataract extraction surgery. To date, no published evidence from clinical trials is available on its in vivo safety and efficacy. Schlemm's canal based glaucoma procedures show promise as alternative treatments to traditional glaucoma surgery. Surgeons must be comfortable with angle anatomy. A prerequisite for functionality of these techniques is the integrity of the distal outflow system. At present, however, it is not possible to conclude whether these novel procedures will be viable alternatives to standard filtering surgery over the long-term. PMID:25624672

  18. New Technologies to Improve Root Canal Disinfection.

    PubMed

    Plotino, Gianluca; Cortese, Teresa; Grande, Nicola M; Leonardi, Denise P; Di Giorgio, Gianni; Testarelli, Luca; Gambarini, Gianluca

    2016-01-01

    Effective irrigant delivery and agitation are prerequisites to promote root canal disinfection and debris removal and improve successful endodontic treatment. This paper presents an overview of the currently available technologies to improve the cleaning of the endodontic space and their debridement efficacy. A PubMed electronic search was conducted with appropriate key words to identify the relevant literature on this topic. After retrieving the full-text articles, all the articles were reviewed and the most appropriate were included in this review. Several different systems of mechanical activation of irrigants to improve endodontic disinfection were analysed: manual agitation with gutta-percha cones, endodontic instruments or special brushes, vibrating systems activated by low-speed hand-pieces or by sonic or subsonic energy, use of ultrasonic or laser energy to mechanically activate the irrigants and apical negative pressure irrigation systems. Furthermore, this review aims to describe systems designed to improve the intracanal bacterial decontamination by a specific chemical action, such as ozone, direct laser action or light-activated disinfection. The ultrasonic activation of root canal irrigants and of sodium hypochlorite in particular still remains the gold standard to which all other systems of mechanical agitation analyzed in this article were compared. From this overview, it is evident that the use of different irrigation systems can provide several advantages in the clinical endodontic outcome and that integration of new technologies, coupled with enhanced techniques and materials, may help everyday clinical practice.

  19. 33 CFR 117.273 - Canaveral Barge Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Canaveral Barge Canal. 117.273 Section 117.273 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.273 Canaveral Barge Canal. (a) The drawspan of the Christa McAuliffe...

  20. 33 CFR 117.159 - Grant Line Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grant Line Canal. 117.159 Section 117.159 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.159 Grant Line Canal. The draw of the San Joaquin County highway bridge, mile 5.5...

  1. 33 CFR 117.235 - Chesapeake and Delaware Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chesapeake and Delaware Canal. 117.235 Section 117.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.235 Chesapeake and Delaware Canal. The draw of the Conrail bridge, mile...

  2. 33 CFR 117.239 - Lewes and Rehoboth Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lewes and Rehoboth Canal. 117.239 Section 117.239 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.239 Lewes and Rehoboth Canal. (a) The draw of the Savannah Road/SR 18...

  3. 33 CFR 117.586 - Annisquam River and Blynman Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Annisquam River and Blynman Canal. 117.586 Section 117.586 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.586 Annisquam River and Blynman Canal. The draw of the Blynman...

  4. 33 CFR 117.181 - Oakland Inner Harbor Tidal Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Oakland Inner Harbor Tidal Canal. 117.181 Section 117.181 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.181 Oakland Inner Harbor Tidal Canal. The draws of the...

  5. 33 CFR 117.769 - Black Rock Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Black Rock Canal. 117.769 Section 117.769 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.769 Black Rock Canal. The draws of...

  6. 33 CFR 117.589 - Cape Cod Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw...

  7. 33 CFR 117.589 - Cape Cod Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw...

  8. 33 CFR 117.589 - Cape Cod Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw...

  9. 33 CFR 117.589 - Cape Cod Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw...

  10. 33 CFR 117.589 - Cape Cod Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw...

  11. Photocopy of photograph (from Barge Canal contract 56, photo album ...

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

    Photocopy of photograph (from Barge Canal contract 56, photo album negative, 49, New York State Archives and Manuscripts), photographer unknown, 1912 View northwest, barge canal sluice around 5 combined, completed - Glens Falls Feeder, Sluice, Along south side of Glens Falls Feeder between locks 10 & 20, Hudson Falls, Washington County, NY

  12. Photocopy of photograph (from Barge Canal contract 56, photo album ...

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

    Photocopy of photograph (from Barge Canal contract 56, photo album negative 26, New York State Archives and Manuscripts), photographer unknown, 1912 View northwest, barge canal sluice around 5 combined under construction - Glens Falls Feeder, Sluice, Along south side of Glens Falls Feeder between locks 10 & 20, Hudson Falls, Washington County, NY

  13. 29. VIEW OF GRAND CANAL, LOOKING WEST TOWARD BROPHY PREP ...

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

    29. VIEW OF GRAND CANAL, LOOKING WEST TOWARD BROPHY PREP AND ST. FRANCIS CHURCH (compare this photograph with AZ-17-15, taken at the same spot in 1937). Photographer: Kevin Kreisel-Coons, May 1990 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  14. 3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH ...

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

    3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH OF THE SPILLWAY; VIEW TO WEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  15. 1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) ...

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

    1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) SOUTH OF THE SPILLWAY; VIEW TO SOUTH. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  16. 2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH ...

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

    2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH OF THE SPILLWAY; VIEW TO SOUTHWEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  17. REACTIVITY MEASUREMENT FACILITY, UNDER CONSTRUCTION OVER MTR CANAL IN BASEMENT ...

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

    REACTIVITY MEASUREMENT FACILITY, UNDER CONSTRUCTION OVER MTR CANAL IN BASEMENT OF MTR BUILDING, TRA-603. WOOD PLANKS REST ON CANAL WALL OBSERVABLE IN FOREGROUND. INL NEGATIVE NO. 11745. Unknown Photographer, 8/20/1954 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  18. Convergence or reticulation? Mosaic evolution in the canalized American Amaryllidaceae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canalization is defined as the suppression of phenotypic variation, or, in the context of molecular evolution, genetic buffering that has evolved under natural selection in order to stabilize the phenotype. Very little is understood on the processes behind canalization, even in today’s genomic era....

  19. 1. General oblique view from south side of Canal Street ...

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

    1. General oblique view from south side of Canal Street showing Paper Machine Building at southwest corner of site; view to northeast. - Champion-International Paper Company, Paper Machine Building, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  20. 3. VIEW EAST, DETAIL OF INTERIOR CANAL WALL (Original Fabric) ...

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

    3. VIEW EAST, DETAIL OF INTERIOR CANAL WALL (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  1. 6. VIEW WEST, INTERIOR CANAL WALL, FLOOR FULLY EXCAVATED (Original ...

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

    6. VIEW WEST, INTERIOR CANAL WALL, FLOOR FULLY EXCAVATED (Original Fabric) - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  2. 7. SAND FILTERS, CANAL TO LEFT. CONCRETE OVERFLOW AREA TO ...

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

    7. SAND FILTERS, CANAL TO LEFT. CONCRETE OVERFLOW AREA TO LEFT OF CANAL ORIGINALLY PLANNED AS A STORAGE LAKE. VIEW LOOKING DUE WEST OF HINDS COMPLEX IN BACKGROUND OF SAND FILTERS. - Hinds Pump Plant, East of Joshua Tree National Monument, 5 miles north of Route 10, Hayfield, Riverside County, CA

  3. 78 FR 10524 - Drawbridge Operation Regulation; Charenton Canal, Baldwin, LA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-14

    ... (BNSF) Railway Company swing span bridge across Charenton Canal, mile 0.4, at Baldwin, St. Mary Parish... temporary deviation from the operating schedule of the swing span railroad bridge across the Charenton Canal... the passage of vessels. This deviation allows the swing span of the bridge to remain in the...

  4. 5 CFR 550.714 - Panama Canal Commission employees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Panama Canal Commission employees. 550... PAY ADMINISTRATION (GENERAL) Severance Pay § 550.714 Panama Canal Commission employees. (a) Notwithstanding any other provisions of this subpart, an employee separated from employment with the Panama...

  5. 5 CFR 550.714 - Panama Canal Commission employees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Panama Canal Commission employees. 550... PAY ADMINISTRATION (GENERAL) Severance Pay § 550.714 Panama Canal Commission employees. (a) Notwithstanding any other provisions of this subpart, an employee separated from employment with the Panama...

  6. 5 CFR 550.714 - Panama Canal Commission employees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Panama Canal Commission employees. 550... PAY ADMINISTRATION (GENERAL) Severance Pay § 550.714 Panama Canal Commission employees. (a) Notwithstanding any other provisions of this subpart, an employee separated from employment with the Panama...

  7. 5 CFR 550.714 - Panama Canal Commission employees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Panama Canal Commission employees. 550... PAY ADMINISTRATION (GENERAL) Severance Pay § 550.714 Panama Canal Commission employees. (a) Notwithstanding any other provisions of this subpart, an employee separated from employment with the Panama...

  8. 5 CFR 550.714 - Panama Canal Commission employees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Panama Canal Commission employees. 550... PAY ADMINISTRATION (GENERAL) Severance Pay § 550.714 Panama Canal Commission employees. (a) Notwithstanding any other provisions of this subpart, an employee separated from employment with the Panama...

  9. 8. FLUME BOX Y, LOOKING NORTH. CANAL HEADING RIGHT FOLLOWS ...

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

    8. FLUME BOX Y, LOOKING NORTH. CANAL HEADING RIGHT FOLLOWS HILLSIDE INTO DRAINAGE; FLUME HEADING LEFT CROSSED GULCH ON A TRESTLE. NOTE CONCRETE ABUTMENTS NEAR TOP RIGHT INSTALLED IN 1935 TO PREVENT WATER FROM ESCAPING CANAL AT OLD TRESTLE ENTRANCE. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  10. 14. ANGULAR QUARTZITE ROCK REINFORCEMENT ON INTERIOR OF OUTSIDE CANAL ...

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

    14. ANGULAR QUARTZITE ROCK REINFORCEMENT ON INTERIOR OF OUTSIDE CANAL BANK, LOOKING SOUTH-SOUTHEAST. CANAL ROUTE VISIBLE ALONG HILLSIDE NEAR TOP LEFT. NOTE DILLON RESERVOIR, HIGHWAY 6, AND NEW RESIDENTIAL CONSTRUCTION AT RIGHT AND CENTER. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  11. 10. CANAL CUT THROUGH SHALE BEDROCK ON PROMINENT POINT, LOOKING ...

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

    10. CANAL CUT THROUGH SHALE BEDROCK ON PROMINENT POINT, LOOKING NORTH-NORTHEAST. NOTE CONCRETE ABUTMENTS PROBABLY INSTALLED IN 1935 TO PREVENT WATER FROM ESCAPING THROUGH A CANAL BANK BREACH. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  12. 5. Lower end of the Old Crosscut Canal, circa 1977 ...

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

    5. Lower end of the Old Crosscut Canal, circa 1977 aerial view. The Old Crosscut runs from bottom right to join the Grand. Note lack of trees, and wasteway to the bed of the Salt River. Photographer unknown. Source: Pueblo Grande Museum Cultural Park. - Old Crosscut Canal, North Side of Salt River, Phoenix, Maricopa County, AZ

  13. 22. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST ...

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

    22. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST FROM BELOW THE SETTLING BASIN (see HAER Photograph No. AZ-30-17, Crosscut Hydro Plant). Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  14. 18. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT BEFORE 1989 ...

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

    18. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT BEFORE 1989 REALIGNMENT, LOOKING NORTH TOWARD RAILROAD CROSSING AND CROSSCUT STEAM PLANT LARGE WHITE BUILDING. THE CROSSCUT HYDRO PLANT IS HIDDEN BY TREES TO RIGHT OF STEAM PLANT. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  15. 63. CANAL BOAT IN CRADLE AT TOP OF PLANE. TO ...

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

    63. CANAL BOAT IN CRADLE AT TOP OF PLANE. TO PASS OVER THE SUMMIT (THE HUMP OF LAND AT THE TOP OF PLANE TO HOLD BACK THE WATER AT THAT LEVEL), THE BOATS HAVE SEEN HINGED AND TWO CRADLES ARE USED TO CARRY THE BOAT UP THE PLANE. - Morris Canal, Phillipsburg, Warren County, NJ

  16. 33 CFR 117.769 - Black Rock Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Black Rock Canal. 117.769 Section 117.769 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.769 Black Rock Canal. The draws of...

  17. 33 CFR 117.769 - Black Rock Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Black Rock Canal. 117.769 Section 117.769 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.769 Black Rock Canal. The draws of...

  18. 33 CFR 117.769 - Black Rock Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Black Rock Canal. 117.769 Section 117.769 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.769 Black Rock Canal. The draws of...

  19. 33 CFR 117.769 - Black Rock Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Black Rock Canal. 117.769 Section 117.769 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.769 Black Rock Canal. The draws of...

  20. 33 CFR 117.159 - Grant Line Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Grant Line Canal. 117.159 Section 117.159 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements California § 117.159 Grant Line Canal. The draw of...