scholarly journals The evaluation of wear of tungsten carbide dental bur

2018 ◽  
Vol 19 (19) ◽  
pp. 6-9
Author(s):  
Barbara Lisiecka

Abstract Due to its durability, tungsten carbide has long been used as a material to produce dental burs. WC– Co burs are designed for smooth, efficient cutting and extended life. Dental burs are available in different sizes and shapes, for example round burs, pear and cylinder-shaped, egg-shaped, as well as there are various tapered ones, which enable an individual selection of the drill for the right treatment. Carbides can be used for standard crowns and bridges, for extensive surgical procedures and they should minimize damage to the existing teeth. The design of WC–Co dental bur reduces a patient’s discomfort because of the operating time and the fact that its liquidity is preserved. The head of the bur (the cutting edge) delivers optimum concentricity and strength. The shank is made from stainless steel allowing a bur to be autoclaved multiple times without the risk of corrosion. The main purpose of this study was to evaluate the wear of a tungsten carbide dental bur. The results of stereoscopy microscope and SEM/EDS analysis are presented.

Wear ◽  
2021 ◽  
Vol 464-465 ◽  
pp. 203537
Author(s):  
Navnath Kalel ◽  
Bhaskar Bhatt ◽  
Ashish Darpe ◽  
Jayashree Bijwe

2017 ◽  
Vol 5 (3) ◽  
pp. 21-29
Author(s):  
Феклин ◽  
S. Feklin ◽  
Графова ◽  
A. Grafova

The right to education is one of the most signifi cant rights of man and citizen. It is determined, fi rst of all, by the important role played by education in the modern world. In accordance with the Constitution of the Russian Federation and the Federal Law “On Education in the Russian Federation”, free and accessible education is guaranteed on the territory of our country. The head of the general education organization must ensure compliance with the rules for admission and individual selection of students for specialized programs. The article describes the legal basis for the admission and individual selection of students for specialized programs, commenting on individual norms of legislation. The authors give examples from the practice on frequently occurring questions of admission to educational organizations.


2008 ◽  
Vol 21 (02) ◽  
pp. 140-146
Author(s):  
M. R. Edwards ◽  
S. P. James ◽  
W. S. Dernell ◽  
R. J. Scott ◽  
A. M. Bachand ◽  
...  

SummaryThe biomechanical characteristics of 1.2 mm diameter allogeneic cortical bone pins harvested from the canine tibia were evaluated and compared to 1.1 mm diameter stainless steel pins and 1.3 mm diameter polydioxanone (PDS) pins using impact testing and four-point bending. The biomechanical performance of allogeneic cortical bone pins using impact testing was uniform with no significant differences between sites, side, and gender. In four-point bending, cortical bone pins harvested from the left tibia (204.8 ± 77.4 N/mm) were significantly stiffer than the right tibia (123.7 ± 54.4 N/mm, P=0.0001). The site of bone pin harvest also had a significant effect on stiffness, but this was dependent on interactions with gender and side. Site C in male dogs had the highest mean stiffness in the left tibia (224.4 ± 40.4 N/mm), but lowest stiffness in the right tibia (84.9 ± 24.2 N/mm). Site A in female dogs had the highest mean stiffness in the left tibia (344.9 ± 117.4 N/mm), but lowest stiffness in the right tibia (60.8 ± 3.7 N/mm). The raw and adjusted bending properties of 1.2 mm cortical bone pins were significantly better than 1.3 mm PDS pins, but significantly worse than 1.1 mm stainless steel pins (P<0.0001). In conclusion, cortical bone pins may be suitable as an implant for fracture fixation based on initial biomechanical comparison to stainless steel and PDS pins used in clinical practice.


Author(s):  
Яна Валерьевна Самиулина

В настоящей статье предпринята попытка исследовать отдельные проблемные аспекты института потерпевшего в российском уголовном процессе. В этих целях подвергнуты анализу правовые нормы, регламентирующие его процессуальный статус. Раскрываются отдельные пробелы уголовно-процессуального законодательства в сфере защиты законных прав и интересов потерпевшего. Автор акцентирует внимание на том, что совершенствование уголовно-процессуального законодательства в части расширения правомочий потерпевшего по отстаиванию своих нарушенных преступлением прав следует продолжить. На основании проведенного исследования действующего законодательства в части регламентации прав потерпевшего от преступления предлагается расширить перечень получаемых им копий постановлений, указанных в п. 13 ч. 2 ст. 42 УПК РФ. Автор предлагает включить в перечень указанной законодательной нормы право получения потерпевшим копии постановления об избрании конкретного вида меры пресечения, избранного в отношении подозреваемого (обвиняемого). Для создания действенного механизма защиты интересов потерпевших от преступления юридических лиц предлагаем ч. 9 ст. 42 УПК РФ изложить в следующей редакции: «в случае признания потерпевшим юридического лица его процессуальное право в уголовном процессе осуществляет представляющий его профессиональный адвокат». This article attempts to investigate certain problematic aspects of the institution of the victim in the Russian criminal process. For this purpose, analyzed the individual norms governing his procedural status. Separate gaps of the criminal procedure legislation in the sphere of protection of the legal rights and interests of the victim are disclosed. The author emphasizes that the improvement of the criminal procedure legislation in terms of the extension of the victim’s authority to defend his rights violated by the crime should be continued. On the basis of the study of the current legislation regarding the regulation of the rights of the victim of a crime, it is proposed to expand the list of decisions received by him, referred to in paragraph 13, part 2 of article 42 Code of Criminal Procedure. The author proposes to include in the list of the indicated legislative norm the right to receive the victim a copy of the decision on the selection of a specific type of preventive measure, selected in relation to the suspect (accused). To create an effective mechanism for protecting the interests of legal entities victims of a crime, we offer part 9 of art. 42 of the Code of Criminal Procedure of the Russian Federation shall be reworded as follows: «if a legal entity is recognized as a victim, his procedural right in criminal proceedings is exercised by the professional lawyer representing him».


Author(s):  
Dmitriy B. Slinko ◽  
Vyacheslav A. Denisov ◽  
Dmitriy A. Dobrin ◽  
Andrey V. Afanas’yev ◽  
Pavel M. Kislov

Reducing operating costs during soil processing and increasing the wear resistance of parts and components is an important condition for reducing the cost of agricultural products, increasing its efficiency and competitiveness. The development of materials with increased wear resistance and new effective technologies for strengthening working bodies in their manufacture is now becoming an urgent task. (Research purpose) The research purpose is increasing the wear resistance of the working bodies of soil-processing machines by electric arc surfacing. (Materials and methods) During the experimental study, it has been performed testing of modes and surfacing of a pilot batch of working bodies from Kverneland for field tests in VIM on an automated installation for electric arc surfacing. Authors used eutectic CastolinEnDotec DO*30 powder wire with a diameter of 1.2 millimeters and a boron content of up to 4 percent for surfacing wear-resistant rollers, which allows to obtain wear-resistant rollers with a hardness of up to 65 HRC without pores and cracks. (Results and discussion) It has been revealed that hardened ploughshares that have passed field tests are subject to lower wear rates compared to non-hardened ones. It was found that when operating time is 24.785 hectares per ploughshare, the wear of the linear size of the cutting edge along the width of hardened ploughshares is on average up to 10-11 millimeters less than that of non-hardened ones. It was found that when processing 228 hectares, the wear of the linear size of the cutting edge along the width of hardened bits is on average up to 9-10 millimeters less than that of non-hardened ones. (Conclusions) The technology of surfacing with intermittent wear-resistant rollers provides an increase in the efficiency of hardening of Kverneland working bodies according to the criterion of wear resistance by an average of 20-30 percent. The adjusted technological parameters of the surfacing process will reduce the wear rate and increase the service life of the blade part of the working bodies, as well as reduce the amount of surfaced material by an average of 60 percent. The continuation of work on strengthening the working bodies should be aimed at changing the surfacing scheme and choosing a cheaper domestic cored wire.


1994 ◽  
Vol 27 (1) ◽  
pp. 33
Author(s):  
Richard Af Petersens ◽  
Ola Runnerstam

Wear ◽  
2021 ◽  
pp. 203788
Author(s):  
Shaogang Cui ◽  
Shenglu Lu ◽  
Kiet Tieu ◽  
Ganesh Kumar Meenashisundaram ◽  
Long Wang ◽  
...  

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 158
Author(s):  
Colin Eady

For 30 years, forage ryegrass breeding has known that the germplasm may contain a maternally inherited symbiotic Epichloë endophyte. These endophytes produce a suite of secondary alkaloid compounds, dependent upon strain. Many produce ergot and other alkaloids, which are associated with both insect deterrence and livestock health issues. The levels of alkaloids and other endophyte characteristics are influenced by strain, host germplasm, and environmental conditions. Some strains in the right host germplasm can confer an advantage over biotic and abiotic stressors, thus acting as a maternally inherited desirable ‘trait’. Through seed production, these mutualistic endophytes do not transmit into 100% of the crop seed and are less vigorous than the grass seed itself. This causes stability and longevity issues for seed production and storage should the ‘trait’ be desired in the germplasm. This makes understanding the precise nature of the relationship vitally important to the plant breeder. These Epichloë endophytes cannot be ‘bred’ in the conventional sense, as they are asexual. Instead, the breeder may modulate endophyte characteristics through selection of host germplasm, a sort of breeding by proxy. This article explores, from a forage seed company perspective, the issues that endophyte characteristics and breeding them by proxy have on ryegrass breeding, and outlines the methods used to assess the ‘trait’, and the application of these through the breeding, production, and deployment processes. Finally, this article investigates opportunities for enhancing the utilisation of alkaloid-producing endophytes within pastures, with a focus on balancing alkaloid levels to further enhance pest deterrence and improving livestock outcomes.


Author(s):  
Mohammad Malekan ◽  
Camilla D. Bloch-Jensen ◽  
Maryam Alizadeh Zolbin ◽  
Klaus B. Ørskov ◽  
Henrik M. Jensen ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
D. Bolla ◽  
N. Deseö ◽  
A. Sturm ◽  
A. Schöning ◽  
C. Leimgruber

Mature cystic teratomas (MCTs) of the ovary represent 44% of ovarian neoplasmas. The surgical approach is important in young women especially for the cosmetic results. Nowadays most of the ovarian surgeries can be performed laparoscopically. An alternative between laparoscopy and laparotomy is the minilaparotomy (ML) which can be an interesting option, thanks to the small incision. We report a 39-year-old woman who was referred to our hospital with acute abdominal pain. In her past history the patient had an uncomplicated delivery. During pregnancy a 6 cm bilateral MCT was diagnosed and expectant management was followed. A left-sided ovarial torsion was postulated, and laparoscopic detorsion was performed. To avoid a rupture of the left MCT, the operation was interrupted. To remove the cyst, a ML was done two weeks later. A left-sided salpingo-oophorectomy was performed due to a large cyst including the entire ovary. On the other side, the right dermoid cyst was entirely removed. The advantage of a ML is not only shorter operating time with less learning curve compared to laparoscopy but also the possibility to extract the adnexal mass from the abdominal cavity with lower risk of rupture and in addition the possibility to preserve more ovarian tissue.


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