Surface modification ofaisi440b stainless steel and its influence on surgical drill bits performance

The development of modern invasive surgery is highly dependent on the performance of surgical instruments, understood as long-term efficiency arising from high resistance to wear and corrosion. In order to maintain sufficient reliability, surgical cutting instruments are often made of martensitic stainless steels. Nevertheless, the use of ferrous alloys in medical applications is still a concern due to their questionable corrosion and wear resistance. To extend their bioconipatibility, improve stability in variable environmental conditions, improve ease of handling, and maximize their performance, diffusion layers and coatings are applied to the surface. The aim of this work was to evaluate the effect of TiN and diamond-like carbon (DLC) surface modification on the performance of surgical drill bits, that is. wear and corrosion resistance, measured in model and field tests. Based on the findings presented, DLC layers can be recommended as anti-wear and anti-corrosion coatings for surgical drill bits

Effect of heat treatment and plasma nitriding on corrosion resistance of 440B martensitic stainless steel

Reliability and durability assurance poses a serious challenge for surgical instruments manufacturers. Hard working conditions, such as intermittent contact with body fluids and hard bone tissues, as well as necessity to undergo frequent sterilisation processes, induce constant research into solutions capable of ensuring high wear resistance while maintaining satisfactory imperviousness to corrosion. Plasma nitriding is marked as the modern corrosion resistance improving method suitable for surgical instruments steels. The paper pre-sents findings from the heat treated and plasma nitrided AISI 440B (PN EN or DIN X90CrMoV18) steel corrosion resistance studies. Three conventionally heat treated (quenched with tempering in 250, 390 or 605°C) and three additionally plasma nitrided in N2:H2 reaction gas mixture (50:50, 35:65 and 20:80 ratio, respectively) specimens groups were examined. Furthermore, the authors evaluated the effect of machining - polishing and sandblasting - on investigated steel corrosion resistance. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. Results showed that, in comparison to conventional heat treatment, plasma nitriding of 440B stainless steel does not significantly affect its corrosive characteristics as far as the uniform nitride layer over the entire detail surface is obtained. The layer heterogeneity results in intensification of corrosion processes, making the material even more susceptible to corrosion than after conventional heat treatment, and contributing to severe, visible even with the unaided eye damages development

Registration of RGB-D images: comparison of pairwise registration variants

W dwuczęściowym artykule skupiono uwagę na problemie rejestracji chmur punktów. W pierwszej części omówiono kluczowe komponenty systemu V-SLAM uzupełnione przykładowymi algorytmami i rozwiązaniami stosowanymi w tych komponentach. W poniższej, drugiej części omówiono różne rodzaje wariantów algorytmu ICP, atrybuty punktów oraz operujące na nich metryki. Następnie omówiono metodykę badań oraz przedstawiono wyniki porównania wybranych wariantów wzajemnej rejestracji.The two-part article focuses on the problem of registration of point clouds. The first part briefly discussed the main components of V-SLAM systems and presented the main steps of the ICP (Iterative Closes Point) algorithm. In the following, second part of the paper, we analyse and compare diverse variants of the ICP algorithm. In particular, we discuss different attributes of points along with operating on them metrics that the ICP can employ. Finally, we present the research methodology and discuss the results of comparison of selected variants of ICP

Registration of RGB-D Images: Components of the System

Dwuczęściowy artykuł dotyczy problemu rejestracji obrazów RGB-D. W robotyce problem ten znany jest pod pojęciem V-SLAM (ang. Visual Simultaneous Localization and Mapping). W poniższej, pierwszej części artykułu omówiono pokrótce główne komponenty typowego systemu rejestracji, a następnie zawężono uwagę do algorytmu ICP (ang. Iterative Closest Point), służącego do wzajemnej rejestracji chmur punktów. W drugiej części artykułu uwagę skupiono na asocjacji chmur punktów, różnego rodzaju atrybutach punktów, które mogą być wykorzystane podczas znajdowania dopasowań oraz szeregu metryk operujących na tych atrybutach. Pokrótce omówiono zastosowaną metodykę badań, zaprezentowano eksperymenty mające na celu porównanie wybranych odmian algorytmu ICP oraz omówiono otrzymane wyniki.The two-part article focuses on the problem of registration of RGB-D images, a problem that in the robotics domain is known as Visual Simultaneous Localization and Mapping, or V-SLAM in short. The following, first part of the article presents a bird’s eye view on the main components of V-SLAM systems and focuses on the ICP (Iterative Closest Point), an algorithm for a pairwise registration of point clouds. In the second part we present different types of attributes of points that can be used during the association step along with different metrics that operate on those attributes and that can be employed during the registration. We also describe the methodology used in the conducted experiments and discuss the results of comparison of selected flavours of ICP

Corrosion Damage Investigation of Silver-Soldered Stainless Steel Orthodontic Appliances Used in Vivo / Ocena Zniszczeń Korozyjnych Używanych In Vivo Stałych Aparatów Ortodontycznych O Połączeniach Lutowanych Na Bazie Srebra

Processes of destruction of products used in orthodontic treatment, e.g. fixed orthodontic appliances, microimplants or dental prostheses considerably limit its operational lifetime and comfort and safety of patients. The objective of the research was to evaluate and assess corrosion damage to silver-soldered stainless steel rapid palatal expansion Hyrax devices. Used in vivo for 2 or 6 months, respectively, RPE (rapid palatal expansion) devices were analyzed macroscopically and in a scanning electron microscope with an energy X-ray analyzer for signs of corrosion. The evaluated appliances showed discernible differences between the overall condition of the noble solders and the stainless steel elements. The Ag-rich solders were chiefly covered in corrosion pits, whereas stainless steel wires, molar bands and Hyrax screws presented corrosion-free surfaces. What is more, the EDS analysis showed differential element composition of the solders. According to the results, noble materials, such as Ag-rich solders, can corrode in a salivary environment when coupled with stainless steel. The selective leaching processes are observed

Ocena zniszczeń korozyjnych używanych in vivo stałych aparatów ortodontycznych o połączeniach lutowanych na bazie srebra

Processes of destruction of products used in orthodontic treatment, e.g. fixed orthodontic appliances, microimplants or dental prostheses considerably limit its operational lifetime and comfort and safety of patients. The objective of the research was to evaluate and assess corrosion damage to silver-soldered stainless steel rapid palatal expansion Hyrax devices. Used in vivo for 2 or 6 months, respectively, RPE (rapid palatal expansion) devices were analyzed macroscopically and in a scanning electron microscope with an energy X-ray analyzer for signs of corrosion. The evaluated appliances showed discernible differences between the overall condition of the noble solders and the stainless steel elements. The Ag-rich solders were chiefly covered in corrosion pits, whereas stainless steel wires, molar bands and Hyrax screws presented corrosion-free surfaces. What is more, the EDS analysis showed differential element composition of the solders. According to the results, noble materials, such as Ag-rich solders, can corrode in a salivary environment when coupled with stainless steel. The selective leaching processes are observed.Procesy niszczenia produktów wykorzystywanych w leczeniu ortodontycznym, takich jak: stałych aparatów ortodontycznych, mikroimplantów oraz elementów protetyki stomatologicznej znacząco skracają trwałość eksploatacyjną wyrobów gotowych oraz obniżają komfort leczenia i poziom bezpieczeństwa pacjentów. Celem pracy jest ocena zniszczeń korozyjnych powstałych podczas eksploatacji wykonanych ze stali nierdzewnej stałych aparatów ortodontycznych typu Hyrax przeznaczonych do poszerzania szczęki na skutek tzw. szybkiej ekspansji podniebienia. Używane in vivo od 2 do 6 miesięcy aparaty RPE (rapid palatal expansion) przeanalizowano makroskopowo, za pomocą skaningowego mikroskopu elektronowego oraz przy użyciu rentgenowskiego spektroskopu dyspersyjnego. Analiza uzyskanych wyników wyraźnie wskazuje na różnicę w ogólnym stanie pomiędzy elementami wykonanymi ze stali nierdzewnej i lutami na bazie srebra. Połączenia lutowane we wszystkich analizowanych aparatach uległy dostrzegalnemu makroskopowo roztwarzaniu korozyjnemu, natomiast części konstrukcyjne wykonane ze stali 316L, takie jak: śruby, druty oraz pierścienie trzonowe wolne były od korozji. Co więcej, wykonana analiza składu chemicznego połączeń lutowanych wykazała nierównomierne rozłożenie pierwiastków stopowych, wskazujące na występowanie korozji selektywnej. Wyniki zrealizowanych badań wskazują, iż w połączeniu ze stalą nierdzewną w środowisku jamy ustnej możliwe jest roztwarzanie korozyjne materiałów szlachetnych, jakimi są luty srebrowe. Obserwuje się ślady zachodzących procesów selektywnego roztwarzania korozyjnego o szczególnie wysokiej intensywności na granicy stal nierdzewna – lut na bazie srebra

Are nanohedgehogs thirsty? Toward new superhydrophobic and anti-icing carbon nanohorn-polymer hybrid surfaces

85% of the world’s polymers production is made up of thermoplastics, and among them, one can find: polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). In this study, these three polymers were applied for the first time as supports for superhydrophobic and anti-icing surfaces created using single walled carbon nanohorns (SWCNH). A facile method of thermal “feathering” was used and the obtained materials were deeply characterized using thermal (thermogravimetry, differential scanning calorimetry) and microscopic (scanning electron microscopy, atomic force microscopy, confocal microscopy) methods as well as tribological and nanoindentation tests. We show that, depending on the polymer, the process of thermal “bulk” or “surface feathering” occurs. The results supported by Hansen Solubility Parameters calculation combined with Molecular Dynamics Simulations allow to explain the stability of surfaces as well as the wetting behavior revealing that all new materials are superhydrophobic. Moreover, some of them exhibit ice-phobic properties, while droplet freezing process is well described by the dynamic growth angle model. Finally, by discussing the mechanical stability, superhydrophobic and anti-icing properties two optimal surfaces (PP + SWCNH 5 min, PE + SWCNH 10 min) are chosen. Both of them possess intermediate values of Young’s modulus and show intermediate values of static contact angle hysteresis. Since the PE-based solids show enhanced tribological performance, tests, PE + SWCNH 10 min sample emerges as the most perspective in practical hydrophobic and anti-icing applications