scholarly journals Use of electronic apex locators may improve determination of working length

2014 ◽  
Vol 15 (4) ◽  
pp. 120-120 ◽  
Author(s):  
Isabel Mello
Keyword(s):  
Working Length ◽  
Improve Determination

scholarly journals DETERMINATION OF THE MAIN PARAMETERS OF THE ROTARY MOWER CUTTING APPARATUS

2020 ◽  
pp. 77-85
Author(s):  
Dmitry Kondratyuk ◽  
Vitaliy Komaha
Keyword(s):  
Cutting Speed ◽  
Soil Surface ◽  
Angular Speed ◽  
Working Length ◽  
Mode Of Operation ◽  
Basic Parameters ◽  
Rotary Cutting ◽  
The Difference ◽  
Translational Speed

For mowing grass during harvesting of hay or haylage, support-free mowers with rotary movement of knives are used mainly, the productivity of which is much greater than segment-finger mowers. Free-cutting cutting apparatuses with rotational movement of knives happen with their rotation around the vertical (rotary) and horizontal (rotary) axes. Mowers that are equipped with rotary cutting devices significantly grind grass, so they are used in mower-grinders and lawn mowers. The purpose of the work is to substantiate the methodology for calculating the structural and kinematic parameters of rotary cutting devices, corresponding to the conditions of their use. The main parameters characterizing the operation of rotary cutting devices are: area, mows than in one revolution of the disk; knife working length; overlapping knives of adjacent rotors; cutting speed. In determining the basic parameters of the rotary cutting apparatus of the mower, the following assumptions were made. It was believed that the angular speed of the rotor and the translational speed of the mower are unchanged, and the movement of the unit is straightforward. In addition, the cutting apparatus performs mowing in a plane parallel to the soil surface, that is, in a plane perpendicular to most plant stems. It is shown that the absolute speed of any point of the knife varies from the maximum value equal to the sum of the peripheral speed of this point and the aggregation speed of the mower, to the minimum - the difference of the above speeds. It was found that the working length of the cutting edge of the knife is directly proportional to the speed of aggregation of the mower and inversely proportional to the angular velocity of the rotor and the number of knives mounted on it. The overlap of the path of the knives of adjacent rotors depends on the radius of the rotor; the number of knives mounted on it and the kinematic mode of operation of the cutting apparatus. Moreover, an increase in the radius of the rotor requires an increase in overlap, and an increase in the kinematic mode and the number of knives leads to a decrease in the overlap between the paths of the knives. The resulting dependence, which allows you to determine the area, mows than in one revolution of the rotor.

Electronic determination of root canal working length in primary molar teeth: an in vivo and ex vivo study

2011 ◽  
Vol 44 (5) ◽  
pp. 402-406 ◽  
Author(s):  
A. P. C. A. Beltrame ◽  
T. C. Triches ◽  
N. Sartori ◽  
M. Bolan
Keyword(s):  
Root Canal ◽  
Ex Vivo ◽  
Primary Molar ◽  
Working Length ◽  
Molar Teeth ◽  
Ex Vivo Study

Shift of ionization equilibrium in spatially confined laser induced plasma

2019 ◽  
Vol 34 (10) ◽  
pp. 1975-1981 ◽  
Author(s):  
Aleksandr S. Zakuskin ◽  
Andrey M. Popov ◽  
Timur A. Labutin
Keyword(s):  
Ionization Equilibrium ◽  
Spatial Confinement ◽  
Laser Induced Plasma ◽  
Atomic Lines ◽  
Improve Determination

Spatial confinement of laser-induced plasma leads to shift of ionization equilibrium and can improve determination of elements by their resonant atomic lines.

The Influence of Cervical Preflaring of Root Canal on Determination of Initial Apical File using Gates Glidden Drills, Protaper, Race and Diamond-Coated Galaxy Files

2012 ◽  
Vol 13 (4) ◽  
pp. 554-558 ◽  
Author(s):  
TS Ashwini ◽  
Sonam Bhandari
Keyword(s):  
Root Canal ◽  
Accurate Determination ◽  
Size Determination ◽  
File Size ◽  
Root Canals ◽  
Multiple Comparison Test ◽  
Rotary Instruments ◽  
Working Length ◽  
Maxillary Premolars

ABSTRACT Aim To investigate the influence of cervical preflaring on apical file size determination using four different rotary instruments. Materials and methods Fifty root canals from extracted human maxillary premolars with complete root formation, straight roots were used for the study. Access opening was done and the working length established with 8 no K-file for each canal. Teeth were randomly divided into five groups of 10 canals. In Group 1- no preflaring was done and acted as control and in Groups 2, 3, 4 and 5 cervical and middle third preflaring of the root canals were done using Gates Glidden drills, Protaper instruments, Race instruments and Galaxy files respectively. After preflaring, the apical file size determination was done and the initial apical file (IAF) was fixed at the working length. Teeth were sectioned transversally 1 mm from the apex, with the binding file in position. The samples were imaged under stereomicroscope with 30× magnification. Root canal and file maximum diameters were recorded for each sample. The readings were subjected to analysis of variance test and Scheffe's multiple comparison test. Results Preflaring with Race instruments lead to most accurate determination of the IAF. It was followed by Protaper, Galaxy files and Gates Glidden drills. Conclusion Traditional method of apical size determination may lead to a substantial underestimation of actual canal size. Cervical preflaring increases the accuracy of apical size determination. Clinical significance Thus, cervical preflaring is recommended before selection of IAF as it increases the accuracy of apical size determination. How to cite this article Ashwini TS, Bhandari S. The Influence of Cervical Preflaring of Root Canal on Determination of Initial Apical File using Gates Glidden Drills, Protaper, Race and Diamond-Coated Galaxy Files. J Contemp Dent Pract 2012; 13(4):554-558.

Modeling of Ethylene in Pipeline Leak Detection System

2004 ◽  
Author(s):  
Jakob Bu¨chert
Keyword(s):  
Real Time ◽  
Detection System ◽  
Leak Detection ◽  
Practical Experience ◽  
Time Model ◽  
Pump Stations ◽  
Pipeline Model ◽  
Improve Determination

This paper describes experiences with an improved equation of state (EOS) for ethylene for an existing real time pipeline model. The main scope of the model is leak detection, batch, contaminant and pig tracking. Altogether the pipeline model includes transportation of batched liquid ethylene, ethane, propane, butane and natural gas liquids (NGL). The pipeline is approximately 1900 miles miles long and includes laterals, 33 pump stations, 9 injection/delivery stations and 5 propane terminals. Originally the model used a BWRS EOS for all the above products. At that time a number of false leak alarms were experienced related to pipeline sections containing ethylene. A case study was carried out, specifically for ethylene, to investigate the effect of replacing the BWRS EOS with a modified Helmholtz EOS. The study showed that replacing the EOS on average would improve determination of the ethylene densities by 1.6%–5.6% with an expected reduction in the alarm rate for ethylene cases by approximately 50%. As a result the modified Helmholtz EOS was implemented in the real time model. Results are presented to show the practical experience with the new EOS gained over the last years.

scholarly journals Influence of cervical preflaring on determination of apical file size in maxillary molars: SEM analysis

2005 ◽  
Vol 16 (3) ◽  
pp. 181-186 ◽  
Author(s):  
José Roberto Vanni ◽  
Roberto Santos ◽  
Orlando Limongi ◽  
Danilo M. Zanello Guerisoli ◽  
Alexandre Capelli ◽  
...  
Keyword(s):  
Cross Sections ◽  
Root Apex ◽  
Sem Analysis ◽  
Pulp Tissue ◽  
Maxillary Molars ◽  
Canal Diameter ◽  
Working Length ◽  
Major Discrepancy ◽  
Post Hoc

The purpose of this study was to investigate the influence of cervical preflaring on determination of the initial apical file in mesiobuccal roots of maxillary molars. Fifty first molars with degree of curvature of the mesiobuccal root between 10° and 15° were utilized. After standard access opening and removal of pulp tissue, the working length (WL) was determined at 1 mm from the root apex. Five groups (n=10) were formed at random, according to the type of cervical preflaring performed. In group 1, the size of the initial apical file was determined without cervical preflaring. In groups 2 to 5, the cervical and middle thirds of the canals were preflared with Gates-Glidden drills, K3 Orifice Opener instruments, ProTaper instruments and LA Axxess burs, respectively. Canals were sized manually with K-files, starting with size 08 K-files, inserted passively up to the WL. File sizes were increased until a binding sensation was felt at the WL and the size of the file was recorded. The binding instruments were fixed into the canals at the WL with methylcyanacrylate. Cross-sections of the WL region were examined under scanning electron microscopy and the discrepancies between the canal diameter and the diameter of first file to bind at the WL were calculated using UTHSCSA ImageTool software. Data were analyzed statistically by ANOVA and multiple comparisons were done by Tukey's HSD post-hoc test. Significant differences (p<0.001) were found among the groups. The major discrepancy was observed for the group without preflaring (mean 0.1543 mm ± 0.0216). Cervical preflaring with LA Axxess burs produced the least discrepancies between the canal size and the diameter of the initial apical instrument (mean 0.026 mm ± 0.0037), followed by ProTaper files (mean 0.0567 mm ± 0.0354). Canals preflared with Gates-Glidden drills and K3 Orifice Opener instruments showed statistically similar discrepancy results to each other (p>0.05) (means 0.1167 mm ± 0.0231 and 0.1313 mm ± 0.0344, respectively). In conclusion, preflaring of the cervical and middle thirds improved the determination of the initial apical instrument. Canals preflared with LA Axxess burs showed a more accurate binding of the files to the anatomical diameter at the WL in the mesiobuccal roots of maxillary first molars.

Sign in / Sign up

Export Citation Format

Share Document