Artificial Canal Research Articles

Cyclic Fatigue Resistance of Nickel-Titanium Rotary Instruments after Simulated Clinical Use.

Objective Cyclic fatigue occurred in the curved canal when the instrument freely rotated leading to repeated compressive and tensile stresses. This study aims to evaluate the cyclic fatigue resistance (CFR) of new and used 2Shape and AF F-One rotary instrument systems by using an artificial stainless-steel canal. Methods A total of 80 rotary nickel–titanium (NiTi) instruments of two systems were used, 2Shape/TS2 and AF F-ONE/F5 (40 in each group). The instruments were subdivided into group A 20 instruments (10 per system) that remain unused, group B 20 instruments (10 per system) instrumented 20 root canals (each file prepared 1 canal for 2 minutes), group C 20 instruments (10 per system) instrumented 40 canals each for 2 minutes (each file prepared 2 canals), group D of 20 instruments (10 per system) prepared 60 canals each for 2 minutes (each file prepared 3 canals). After each canal instrumentation, the instruments were cleaned and sterilized by autoclave. Then, all the instruments underwent cyclic fatigue testing in an artificial stainless steel canal with a 50° canal curvature and a radius of curvature of 5 mm. The time and number of cycles to failure (NCF) were recorded. Data were analyzed using the Welch ANOVA test for intragroup comparison and the pairwise test for multiple comparisons. Results The unused instruments of the AF F-One rotary system showed statistically higher CFR than clinically used instruments (P < 0.05). 2Shape system was not affected by clinical use (P > 0.05). The mean NCF of AF F-One instruments was significantly higher than the equivalent file group of 2Shape instruments (P < 0.05). Conclusion A reduction in the CFR for AF F-One instruments after use was observed when compared to the new unused file group. The 2Shape system was not affected by clinical use. AF F-One performed better in terms of NCF.

Development of the Dethridge Wheel Blade Shape for Hydropower Generation in Irrigation Canals in Indonesia

Consumption of electrical energy continues to increase along with population growth. As a result, various sources of electrical energy are utilised to meet these needs, especially in areas that have not been reached by the national electricity network. In countries with hilly geography and irrigation canals, pico hydro energy is often considered an alternative. One of the tools used to convert water flow energy into electrical energy is the Dethridge wheel. The Dethridge wheel is a simple waterwheel that is easy to manufacture and suitable for irrigation canals with very low water head heights. This study aims to increase the performance of the Dethridge wheel by changing the shape of the wheel blades and examine the effect of the variation of water flow rate in the channel. Experimental and numerical methods were used to investigate the potential of the developed wheel. The Dethridge wheel and its development were tested using an artificial irrigation canal with flow rates of 20, 30, 60, 90 and 120 m3/h. Furthermore, a three-dimensional numerical model of the Dethridge wheel was simulated using Ansys Fluent 18.2 software. The highest efficiency of the experimental Dethridge wheel, 55.6%, was achieved when the flow rate was 30 m3/h. The developed Dethridge wheel efficiency increased to 71.72%. These results are also in agreement with the simulated model.

CYCLIC AND TORSIONAL FATIGUE RESISTANCE OF THREE DIFFERENT THERMALLY TREATED NICKEL-TITANIUM ROTARY INSTRUMENTS

&#x0D; &#x0D; &#x0D; Background: The aim of this study was to evaluate the cyclic fatigue and torsional fatigue resistance of three thermally treated rotary instruments, such as: Logic 2 25.05 (LOG 25.05), Edge Taper Platinum 25.06 (EDT 25.06) and ProTaper Gold 25.08 (PTG 25.08).Methods: A total of 60 rotary instruments of LOG 25.05, EDT 25.06 and PTG 25.08 were used (n=20). Cyclic fatigue tests were performed at 36°C using an artificial stainless steel canal with a 60o angle and a 5-mm radius of curvature. The time (in seconds) and number of cycles to fracture (NCF) was recorded. The torsional test evaluated the torque and angle of rotation to failure at 3 mm from the tip according to ISO 3630-1. The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). Data were analyzed using one-way ANOVA and Holm-Sidak’s tests for multiple comparison, the level of significance was set at 5%.&#x0D; Results: EDT 25.06 had highest cyclic fatigue resistance (time and NFC), followed by LOG 25.05 and PTG 25.08 (P&lt;0.05). There were no significantly difference between LOG 25.05 and ETP 25.06 regarding the NCF (P&gt;0.05). In relation the torsional test, the LOG 25.05 and ETP 25.06 presented similar torque (P&gt;0.05). The PTG presented greater torque than the other groups (P&lt;0.05). The PTG 25.08 presented the lowest angular rotation to fracture than the other groups (P&lt;0.05). The SEM images demonstrated typical features of cyclic and torsional fracture.&#x0D; &#x0D; &#x0D;

Impact of sodium hypochlorite irrigant on fatigue resistance of different nickel-titanium instruments

Aim: The purpose of this study was to investigate the resistant of three NiTi files, ProTaper (PTN), Hyflex EDM and 2Shape (TS) to cyclic fatigue after being immersed in a 2.5 percent NaOCl irrigant solution in different times (1&amp;5 minutes) at 37°C. Materials and Methods: Seventy-two heat treated files used in this study, divided into three main groups (n=24) according to their metallurgy group-1: PTN, group-2: Hyflex EDM and group-3: TS files each group then subdivided into three subgroups, subgroup-1 immersed in 2.5 percent NaOCl for 1minute at 37°C subgroup-2 immersed in 2.5 percent NaOCl for 5 minutes at 37°C and subgroup-3 did not undergo any immersion as a control group. All files were put through cyclic fatigue testing in a digital water bath at 37°C to imitate body temperature in a stainless-steel artificial canal. The time to fracture was recorded in minutes, then by multiplying the time to fracture by the rotations per minute, the number of cycles to fracture (NCF) was calculated. The data were checked for normality before running a one-way ANOVA with a post hoc test.

Variability of Water Exchange in the Hyporheic Zone of a Lowland River in Poland Based on Gradientometric Studies

Abstract The Moszczenica is a lowland river, which is a third-order river with a length of 55 km; it flows into the Bzura River in central Poland. The objective of this study was to evaluate two important factors in the exchange between surface water and groundwater in the hyporheic zone: a considerable change in water flow conditions and various origins of riverbed sections, natural and artificial. To identify the spatial variation of the hydraulic gradient in the hyporheic zone of the river, a gradientmeter was applied. The measurements show that at low water stages, upwelling was dominant, with an evidently inactive zone, whereas downwelling was inconsiderable. However, the morphology of the riverbed changed during the flood flow, and downwelling clearly dominated. Upwelling zones retained their activity despite a major change in hydrological conditions. Present studies on the artificially dug Moszczenica Canal have documented outflow of water from an artificial medieval canal to a naturally formed drainage base. This means that despite the passage of hundreds of years, the natural drainage base of the Moszczenica River is still active. Studies have demonstrated the applicability of the gradientmeter for evaluating the interaction between surface and groundwaters in the hyporheic zone.

Torsional, Static, and Dynamic Cyclic Fatigue Resistance of Reciprocating and Continuous Rotating Nickel-Titanium Instruments

IntroductionThe aim of this study was to evaluate torsional, dynamic, and static cyclic fatigue resistance of the reciprocating One RECI (OR; Micromega, Besançon, France), WaveOne Gold (WOG; Dentsply Maillefer, Ballaigues, Switzerland), rotary One Curve (OC, MicroMega), and ProTaper Next X2 (PTN X2; Dentsply Sirona, Charlotte, NC) instruments. MethodsA total of 120 OR (n = 30), WOG (n = 30), OC (n = 30), and PTN X2 (n = 30) nickel-titanium instruments were used. Torque and rotation angle until failure under static torsion loading were measured according to ISO 3630-1. Static and dynamic fatigue resistance was measured as the time to fracture in an artificial stainless steel canal with a 60° angle and 5-mm radius of curvature at intracanal temperature. The results were analyzed with 1-way analysis of variance and the post hoc Tukey test. The alpha-type error was set at 5%. Fracture instruments from torsion and fatigue tests were examined with a scanning electron microscope. ResultsOR showed higher static fatigue resistance and rotation angle at fracture than WOG, OC, and PTN X2 (P < .05). WOG exhibited higher torsional resistance than the others (P < .05). The cyclic fatigue tests in dynamic mode had higher TTF than static for the PTN X2 and WOG groups (P < .05). In the dynamic tests, OR and WOG showed higher TTF than OC and PTN X2 (P < .05). ConclusionsUnder these experimental conditions, One RECI exhibited suitable mechanical properties with the highest cyclic fatigue resistance and angle of rotation among the tested instruments.

Glass eel (Anguilla anguilla L. 1758) feeding behaviour during upstream migration in an artificial waterway

The transition from marine to fresh water is a challenging task for juvenile eels. This critical step in the early eels' life is preceded by a metamorphosis from the oceanic larval to the continental glass eel stage, requiring major energy-demanding morphological, physiological and behavioural modifications during which time these animals do not feed. The success of the glass eels' inland migration after metamorphosis will largely depend on remaining energy levels, which can be supplemented only by resuming food uptake. Although it is crucial for their survival and the maintenance of the population, the feeding behaviour of glass eels is still an understudied aspect of the eels' complex life cycle. Many uncertainties about the phenology, diet, potential prey preferences and their relation with migration modus (migratory vs. sedentary) still remain. In this study, the authors analysed the stomach and gut contents of 458 European glass eels (Anguilla anguilla L. 1758) captured in a drainage canal connecting a small mesotidal estuary with an adjacent polder area during the spring migration seasons of 2016 and 2017. They demonstrated that although glass eels started feeding briefly upon arrival in the estuary, food uptake for early arrivals was restricted to a minority that sparsely feed on detritus and some worm-like benthic invertebrates. Along the season, food uptake intensified eventually engaging all glass eels and their dietary palette diversified including a wide array of planktonic and benthic organisms. Crustacean plankton (mainly cyclopoid copepods) was an important part of the glass eel diet, whereas benthic oligochaetes were less abundant as food source in spite of their high presence in the sediments. No clear differences in feeding behaviour could be observed between migratory and sedentary glass eels. This study showed that glass eels can use highly artificial and dynamic drainage canals as feeding ground during their critical marine/freshwater transition. This outcome is also a plea to improve the accessibility of alternative (unnatural) migration routes between the ocean and suitable freshwater growth habitats for the European eel.

Where ecologically ‘tis better to go brown than green: enhanced seagrass macrobenthic biodiversity within the canals of a brownfield coastal marina

At the start of the 21st century, a coastal residential-estate marina was developed on a previously degraded and polluted brownfield island site within Knysna estuarine bay, Garden Route National Park, South Africa, including the creation of 25 ha of new flow-through tidal canals. Canals near the larger entrance to this system now support permanently submerged beds of seagrass, which in turn support abundant macrobenthic invertebrates. In comparison with equivalent seagrass-associated assemblages present in natural channels around the island, those in the artificial marina canals were similarly structured and dominated by the same species, but the marina assemblages were significantly more species-rich (1.4 x on average) and were more abundant. Indeed, this area of marina supports the richest seagrass-associated macrofaunal biodiversity yet recorded from South Africa. The canals created de novo therefore now form a valuable addition to the bay’s marine habitat, in marked contrast to the generality that marinas developed on greenfield sites represent a net reduction in intertidal and shallow marine area and associated seagrass-associated benthos. If located and constructed appropriately, brownfield marina development and conservation of coastal marine biodiversity clearly need not be antithetical, and brownfield sites may provide opportunity for the location and management of ‘artificial marine micro-reserves’ or for the action of ‘other effective area-based conservation measures’ for soft-sediment faunas.

Hydro-dynamic and geochemical assessment of three successive cutoff meanders of the Danube Delta

Abstract Hydrological and sedimentological data were collected on several cross-sections of both natural and artificial canals of three cutoff meanders (Mahmudia, Dunavăţul de Sus, and Dunavăţul de Jos meanders) of the Sfântu Gheorghe branch at the beginning of June 2017. The hydrological data shows a heterogeneous distribution of water discharges: on the meanders of Mahmudia and Dunavăţul de Jos, most of the liquid flow passes through artificial channels. In the case of the Dunavăţul de Sus meander, the cut meander is the main transport channel for the liquid flow. The statistical analysis of chemical data evidenced an excellent quality of the bottom sediments, with few parameters exceeding the limits (for Ni, Cu, and Cr). These results correlated with the hydrological measurements made on each investigated cross-section.

EVALUATION OF ENVIRONMENTAL SITUATION IN NARTA LAGOON, VLORA, ALBANIA

Narta Lagoon is one of the biggest Lagoons in Albania. It is situated in the southern part of the Vjosa River delta. Two canals in the northwest and southwest parts of the lagoon connect it to the Adriatic Sea. These artificial canals enable the water exchange process with the sea during tidal flow. Vjose - Narta area is considered a Protected Landscape, so environmental monitoring is important. Setting and design: Water samples were taken monthly, at six evenly distributed sample stations. The study was conducted from January – to December 2018. Materials and methods: The assessment of microbial contamination was performed with the MPN method. Total coliform, fecal coliform, and fecal streptococci were tested as fecal contamination indicators. PH and salinity were the physicochemical parameters analyzed. Conclusions: the cleanest sampling station is the one near contact with the seawater. The most polluted stations are stations 2, 4, and 6. Temperature values range from 5 oC in January to 33 oC in August. Lagoon pollution is caused by an anthropogenic factor as well as a lack of appropriate cleaning strategies.

Irrigant flow in the root canal during ultrasonic activation: A numerical fluid-structure interaction model and its validation.

AimThe aim of the study was (a) to develop a three‐dimensional numerical model combining the oscillation of a tapered ultrasonic file and the induced irrigant flow along with their two‐way interaction in the confinement of a root canal. (b) To validate this model through comparison with experiments and theoretical (analytical) solutions of the flow.MethodologyTwo partial numerical models, one for the oscillation of the ultrasonic file and another one for the irrigant flow inside the root canal around the file, were created and coupled in order to take into account the two‐way coupled fluid–structure interaction. Simulations were carried out for ultrasonic K‐files and for smooth wires driven at four different amplitudes in air or inside an irrigant‐filled straight root canal. The oscillation pattern of the K‐files was determined experimentally by Scanning Laser Vibrometry, and the flow pattern inside an artificial root canal was analysed using high‐speed imaging together with Particle Image Velocimetry. Analytical solutions were obtained from an earlier study. Numerical, experimental and analytical results were compared to assess the validity of the model.ResultsThe comparison of the oscillation amplitude and node location of the ultrasonic files and of the irrigant flow field showed a close agreement between the simulations, experiments and theoretical solutions.ConclusionsThe model is able to predict reliably the file oscillation and irrigant flow inside root canals during ultrasonic activation under similar conditions.

Evaluation Of Effect Of Root Canal Irrigating Solutions On The Cyclic Fatigue Resistance Of Rotary Nickel-Titanium File – An In-Vitro Study

Aim- The aim of this in-vitro study was to compare the effect of NaOCl, EDTA, Propolis and Distilled water on cyclic fatigue resistance of Protaper Gold rotary NiTi instruments.&#x0D; Method- A total of 40 commercially available rotary (n =40) Ni-Ti files were used to assess the effect of different root canal irrigants on their cyclic fatigue resistance. The files were divided into four groups (n=10 per group) as Group 1- Distilled water (Control group), Group 2 – 5.25 % NaOCl, Group 3 -17% EDTA and Group 4 - Propolis. The instruments were rotated in custom-made stainless steel artificial canal (angle of 60˚and 5 mm radius), fixed in a glass container with irrigating solution until the instrument fractured. The time to fracture was registered for each instrument and the number of cycles to fracture (NCF) was calculated and statistical analysis was done.&#x0D; Result- NiTi files used with Group 1 (Distilled water) exhibited best cyclic fatigue resistance (1386.50±37.12) amongst all the tested groups followed by Group 4 (Propolis) and Group 3 (EDTA). Group 2 (5.25 % NaOCl) showed least cyclic fatigue resistance (971.50 ± 48.879) compared to other groups (P&gt;0.05). &#x0D; Conclusion- NiTi files exhibited best cyclic fatigue resistance when used with distilled water and NaOCl irrigating solution significantly deteriorated the surface characteristics and cyclic fatigue resistance of rotary NiTi files.

A Comparative Study of Two Martensitic Alloy Systems in Endodontic Files Carried out by Unskilled Hands

The aim of this study was to compare the behavior of two heat-treated file systems on resin blocks in unskilled hands. For this purpose, an in vitro, randomized, cross-sectional study was conducted to compare ProTaper Gold (PTG) with BlueShaper (BS) files. A total of 81 resin blocks were used and analyzed photographically to assess the amount of material removed during instrumentation. PTG removed more material on the outside of the curve in the coronal and apical third, while BS removed more material on the inner part of the curve in the middle third. The procedural errors observed in the total sample were apical transportation (33.8%), blockages (4.9%), ledges (3.7%), and canal perforation. PTG produced more apical transportation, and there were no statistically significant differences between the groups in the formation of ledges, canal perforations, or blockages. No file fractures were recorded during the study. Within the limitations of this study, we can affirm that neither file excessively deformed the artificial canals, and the PTG file produced more apical transportation.

Torsional Fracture Resistance of Niti Rotary Glide Path Files under Flexural Stress

This study aimed to evaluate the effects of flexural stress on the torsional fracture resistance of NiTi glide path files. PathFile #16/02, RaCe #15/04, RaCe Evo #15/04, HyFlex EDM #15/03, TruNatomy Glider #17/02, and V Taper 2H #17/04 were examined by scanning electron microscopy (SEM) (n = 3/brand) and subjected to differential scanning calorimetry (n = 2/brand). Torsional fracture resistance testing was performed in straight (ISO 3630-1) and flexural modes (n = 15/brand/mode). Flexural mode testing involved instruments rotating within a stainless-steel artificial double-curved canal. Ultimate strength and distortion angle until failure were recorded, and fractured instruments were examined by SEM. Statistical analyses involved independent sample t-test and one-way analysis of variance with Games–Howell pots hoc test. Austenitic transformation- finishing temperatures of heat-treated files were above body temperature. For RaCe Evo, HyFlex EDM, TruNatomy Glider, and V Taper 2H, the flexural mode resulted in a significantly higher distortion angle compared to the straight mode (p &lt; 0.05). The maximum torque of RaCe Evo, HyFlex EDM increased with the flexural stress (p &lt; 0.05). V taper 2H showed the highest distortion angle and ultimate strength. SEM showed typical patterns of torsional fracture for all tested files. The flexural stress positively affected distortion angle of heat-treated NiTi glide path files.

Comparative evaluation of fracture resistance of hyflex edm, neolix neo niti, protaper next and protaper gold files- an in-vitro study

Aim: The purpose of the present research was to assess the comparison of the fracture resistance ability of various endodontic files like- Hyflex EDM, Neolix Neo NiTi, Protaper Next and Protaper Gold. Methodology: All the instruments were subjected to fracture test using a stainless-steel artificial canal. Time required for fracture as well as number of cycles to failure was calculated at 5 and 8 mm distance from the end of root canal tip. The fractured surfaces were then visualized using electron microscope. The data was analysed using student t-test and Weibull reliability estimation. Results: Hyflex EDM OneFile instruments showed significantly greater cyclic fatigue resistance than protaper Gold Primary instruments as well as protaper next and neolix NiTi. A significant difference was found between the groups for the length of the fracture 5 mm from the tip (P &lt; 0.01). No significant difference was found between the groups for the length of the fracture 8 mm from the tip (P &gt; 0.01). Conclusion: Hyflex EDM OneFile demonstrated the highest performance in terms of cyclic fatigue resistance.

Effect of Rotational Speed on the Resistance of NiTi Alloy Endodontic Rotary Files to Cyclic Fatigue-An In Vitro Study.

The present study aims to evaluate and contrast the function of the rotational speed of NiTi alloy endodontic rotary files on how resistant they are to dynamic cyclic fatigue. Methods: A total of 150 NiTi alloy endodontic rotary files with similar geometrical design and metallurgical properties were randomly divided into study groups: Group A: 200 rpm (n = 30); Group B: 350 rpm (n = 30); Group C: 500 rpm (n = 30); Group D: reciprocating movement at 350 rpm with 120° counterclockwise and 30° clockwise motion (350 rpm+) (n = 30); and Group E: reciprocating movement at 400 rpm with 120° counterclockwise and 30° clockwise motion (400 rpm+) (n = 30). A dynamic device was designed to carry out dynamic cyclic fatigue tests using artificial root canal systems made from stainless steel with an apical diameter of 250 µm, 5 mm radius of curvature, 60° curvature angle, and 6% taper, and 20 mm in length. A Weibull statistical analysis and ANOVA test were used to analyze the results. Results: The ANOVA analysis showed differences in time to failure among all the study groups that were of statistical significance (p < 0.001). Conclusions: NiTi alloy endodontic rotary files using reciprocating movement at 350 rpm with 120° counterclockwise and 30° clockwise motion exhibit greater resistance to dynamic cyclic fatigue than files used with a reciprocating movement at 400 rpm with 120° counterclockwise and 30° clockwise motion, continuous rotational speed at 200 rpm, continuous rotational speed at 350 rpm, or continuous rotational speed at 500 rpm; it is therefore advisable to use reciprocating movements at a low speed.

In vitro evaluation of cyclic fatigue resistance of thermally treated novel nickel-titanium rotary instruments

The objective of this study was to evaluate the cyclic fatigue resistance of novel NiTi files (subjected to heat treatment) using the in vitro model (artificial canal). Twelve ProDesign Logic instruments - PDL 25/.06 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) and 12 Protaper Next X2 instruments - PTN (tip 25) were included in this research. The Static cyclic fatigue test was performed with a grooved stainless steel block simulating a canal of 1,5 mm diameters, a 60o angle of curvature and 5 mm radius. The files were positioned inside the artificial canal and rotated until the fracture occurred. Using the time until fracture (seconds) and the number of rotations per minute (RPM), the number of cycles until fracture (NCF) was calculated and the length of ruptured fragments was registered. Three samples from each group were analyzed in Scanning Electronic Microscopy (SEM) to characterize the metal rupture. Data were analyzed using the Mann-Whitney non-parametric test and the level of significance considered was p&lt;0.05. PDL obtained a mean value of 956,0 NCF (352,0 - SD) and PTN achieved 391,0 NCF (36.7 - SD) with statistical significance between the groups (p &lt; 0.001). There was no statistical difference on fragment length (p &gt; 0.05). SEM analysis showed features compatible with ductile fracture. ProDesign LOGIC files showed higher NCF than Protaper Next X2. There was no difference between groups considering the length of the ruptured fragment.

Effect of NaOCl and EDTA irrigating solutions on the cyclic fatigue resistance of EdgeTaper Platinum instruments

BackgroundTo compare the solution on the cyclic fatigue resistance of EdgeTaper Platinum (ETP) instruments with that of ProTaper Gold (PTG) in the presence of ethylenediaminetetraacetic acid (EDTA) or sodium hypochlorite (NaOCl) irrigating solutions.MethodsSixty PTG and 60 ETP instruments with the same size (#25) and taper (8%) were tested under 17% EDTA, 5.25% NaOCl, or distilled water (n = 20 each). Cyclic fatigue was tested using artificial canals that were milled in stainless steel blocks using a laser micromachining technique. The canals had a curvature angle of 60 and a curvature radius of 5 mm. The center of maximum curvature was set at 5 mm from the instrument tip. The block of artificial canals was stabilized inside a container that was filled with one of the tested solutions. The temperature was fixed at 37 °C with a tolerance limit of 1 °C. The number of cycles to fracture (NCF) was calculated and the fractured surfaces were examined using a scanning electron microscope. All statistical analyses were performed using SPSS software Version 20 (IBM-SPSS Inc., Chicago, IL) at a confidence level of 95%.ResultsETP showed higher NCF than PTG in any of the tested solutions (P < 0.05). Within each group, NaOCl drastically decreased the NCF compared to water and EDTA (P < 0.05) and changing the solution from distilled water to EDTA did not affect the fatigue resistance (P > 0.05).ConclusionsETP showed improved cyclic fatigue performance compared to PTG in all tested irrigating solutions. EDTA can be used in combination with NiTi instruments during canal instrumentation without compromising the cyclic fatigue resistance of PTG and ETP instruments. However, NaOCl drastically decreased the NCF.

Inclusion of flood diversion canal operation in the H08 hydrological model with a case study from the Chao Phraya River basin: model development and validation

Abstract. Water diversion systems play crucial roles in assuaging flood risk by diverting and redistributing water within and among basins. For flood and drought assessments, including investigations of the effects of diversion systems on river discharge worldwide, the explicit inclusion of these systems into global hydrological models (GHMs) is essential. However, such representation remains in the pioneering stage because of complex canal operations and insufficient data. Therefore, we developed a regionalized canal operation scheme and implemented it in the H08 GHM for flood diversion in the Chao Phraya River basin (CPRB), Thailand, which is a complex river network with several natural and artificial diversion canals and has been subject to severe flooding in the past, including recent years. Region-specific validation results revealed that the enhanced H08 model with the regionalized diversion scheme could effectively simulate the observed flood diversion pattern in the CPRB. Diverted water comprises approximately 49 % of the annual average river discharge in the CPRB. The simulations further confirmed that the presented canal scheme had the potential to reduce flood risk in the basin by significantly reducing the number of flooding days. A generalized canal scheme with simple input data settings was also constructed for future global applications, providing insights into the maximum level of discharge reduction achievable with diversion of nearly 57 % of the annual average river discharge of the CPRB. Overall, the enhanced H08 model with canal schemes can be adapted and applied to different contexts and regions, accounting for the characteristics of each river network by maintaining the basic principles unaltered.

Fatigue strength of Bassi LogicTM and Hyflex EDM endodontic instruments in an artificial canal with an extreme curvature

The objective of this study was to perform a comparative analysis of the fatigue strength of NiTi instruments in an in vitro model (artificial canal). Ten Hyflex EDM instruments (tip: 10; taper: .05) (Coltene/Whaledent, Altstätten, Switzerland) and ten Bassi LogicTM instruments (tip: 15; taper: .05) (Bassi Endo, Belo Horizonte, Brazil) were used. For the static bending fatigue strength test, we used a stainless-steel artificial canal with a 5-mm curvature radius, 90º curvature, and inner diameter of 1.5 mm. The instruments were run in the artificial canal until the occurrence of fracture. The time was recorded and the number of cycles was calculated. The length of the fragments was measured and three samples from each group were analyzed using scanning electron micrscopy for the characterization of metal fatigue. The data were compared using the nonparametric Man-Whitney test (samples with non-normal distribution), with the significance level set at 5% (p&lt;0.05). Bassi LogicTM instruments tolerated a greater number of cycles compared to the Hyflex EDM (p &lt; 0.05). Significant differences in fragment size were also found between groups (p &lt; 0.05). Mean fragment size was larger among the Hyflex EDM instruments compared to the Bassi LogicTM instruments.The Bassi LogicTM 15.05 exhibited greater fatigue strength in artificial canals with an accentuated curvature compared to Hyflex EDM 10.05.