Wyniki wyszukiwania - BazTech

1

Dimensional accuracy and surface roughness of polymeric dental bridges produced by different 3D printing processes

Dikova T. D., Dzhendov D. A., Ivanov I., Bliznakova K.

Archives of Materials Science and Engineering

|

2018

|

Vol. 94, nr 2

65--75

EN

Purpose: To compare the dimensions accuracy and surface roughness of polymeric dental bridges produced by different 3D printers. Design/methodology/approach: Four-part dental bridges were manufactured by three printing systems working on the basis of digital light projection (DLP) stereolithography (SLA), laser-assisted SLA and fused deposition modeling (FDM). The materials used from SLA printers are liquid methacrylate photopolymer resins, while FDM printer use thin wire plastic polylactic acid. The accuracy of the external dimensions of dental bridges was evaluated and the surface roughness was measured. Findings: It was found that compared to the base model, the dimensions of the SLA printed bridges are bigger with 1.25%-6.21%, while the corresponding dimensions of the samples, made by FDM are smaller by 1.07%-4.71%, regardless the position of the object towards the substrate. The samples, produced by FDM, are characterized with the highest roughness. The average roughness deviation (Ra) values for DLP SLA and lase-assisted SLA are 2.40 pm and 2.97 pm, respectively. Research limitations/implications: For production of high quality polymeric dental constructions next research should be targeted to investigation of the polymerization degree, stresses and deformations. Practical implications: Our study shows that 3D printers, based on laser-assisted and DLP SLA, can be successfully used for manufacturing of polymeric dental bridges - temporary restorations or cast patterns, while FDM system is more suitable for training models. The results will help the dentists to make right choice of the most suitable 3D printer. Originality/value: One of the largest fixed partial dentures - four-part bridges, produced by three different commercial 3D printing systems, were investigated by comparative analysis. The paper will attract readers’ interest in the field of biomedical materials and application of new technologies in dentistry.

2

Analysis of forming tread wheel sets

Ivanov I., Evseev D., Ovsyanikova I., Tarapanov A.

Transport Problems

|

2017

|

T. 12, z. 3

35--42

EN

This paper shows the results of a theoretical study of profile high-speed grinding (PHSG) for forming tread wheel sets during repair instead of turning and mold-milling. Significant disadvantages of these methods are low capacity to adapt to the tool and inhomogeneous structure of the wheel material. This leads to understated treatment regimens and difficulties in recovering wheel sets with thermal and mechanical defects. This study carried out modeling and analysis of emerging cutting forces. Proposed algorithms describe the random occurrence of the components of the cutting forces in the restoration profile of wheel sets with an inhomogeneous structure of the material. To identify the statistical features of randomly generated structures fractal dimension and the method of random additions were used. The multifractal spectrum formed is decomposed into monofractals by wavelet transform. The proposed method allows you to create the preconditions for controlling the parameters of the treatment process.

3

Analysis of the physical foundations of the build quality of the diagnosis structures based on electronic means of recording and analyzing the parameters of electromagnetic radiation mechanical contact connections

Grachev N., Uvaysov S., Ivanov I., Wójcik W., Komada P., Shedreyeva I., Karnakova G.

Przegląd Elektrotechniczny

|

2017

|

R. 93, nr 5

138--143

EN

The paper presents the results of research that can be put into the development and research of non-contact rapid method for assessing the quality of the assembly and installation of EM designs. To achieve the objectives, studied the behavior of the mechanical connection of the contact pairs, namely the definition of the contribution of R,L,C parameters contact joints in the modulation level and the spectral composition of the electromagnetic radiation mechanical contact pair.

PL

W artykule przedstawiono wyniki badań, które mogą być wprowadzane do rozwoju oraz badań bezdotykowego szybkiego sposobu oceny jakości montażu i instalacji projektów EM. W tym celu zbadano zachowanie połączenia mechanicznego pary styków, mianowicie zdefiniowano wpływ parametrów R, L, C połączeń stykowych na poziom modulacji i skład widmowy promieniowania elektromagnetycznego mechanicznego styku par.

4

The possibilities of improving the operational characteristics of vehicle gear by the use of cylindrical arched tooth gear drive

Ivanov I., Rubin P., Tarapanov A., Kanatnikov N.

Transport Problems

|

2016

|

T. 11, z. 2

61--66

EN

In this article, one of the most promising methods of increasing the operational characteristics of a vehicle gear by the use of cylindrical gear drives with arched teeth is presented. Despite a number of advantages, these gearings are not widely used due to design and manufacture complexity. Possible options of edge cutting machining of cylindrical gearwheel arched teeth are considered. The progressive process technology proposed by the authors combines the roughing by multi-purpose cutter head for bevel gear with circular tooth and finishing by cutter head with zero angle of cutting edge.

RU

В статье представлен один из перспективных способов повышения эксплуатационных характеристик приводов транспортных средств за счет применения цилиндрических передач с арочными зубьями. Несмотря на целый ряд преимуществ, такие передачи не имеют широкого распространения это связано сосложностью их проектирования и изготовления. Рассмотрены возможные варианты лезвийной обработки арочных зубьев цилиндрических колес. Авторами предложен прогрессивный технологический процесс. Сочетающий черновую обработку универсальными резцовыми головками для обработки конических колес скруговым зубом и чистовую - резцовыми головками с нулевым углом профиля.

5

The development of wooden bridges through the ages – a review of selected examples of heritage objects. Part 2 – the iconic structures from the western slavdom area and those that inspired them

Partov D., Maślak M., Ivanov I., Petkov M., Sergeev D., Dimitrova A.

Czasopismo Techniczne. Budownictwo

|

2016

|

Y. 113, iss. 2-B

107--120

EN

In the second part of this article, the development of the timber bridges is shown in detail in relation to the historical and cultural contexts specific to different regions subjectively selected from around the world. For such a purpose, some iconic timber bridges are presented and discussed on a country by country basis. Their mutual comparison allows us not only to appreciate the craftsmanship of both ancient and medieval builders but also to see the diversity of the proposed structural solutions.

PL

W drugiej części niniejszego artykułu pokazano szczegółowo rozwój mostów drewnianych, odnosząc go do historycznych i kulturowych kontekstów specyficznych dla różnych regionów subiektywnie wybranych z całego świata. W tym celu niektóre ikoniczne obiekty mostowe są prezentowane i omawiane kraj po kraju. Ich wzajemne porównanie pozwala nie tylko na docenienie rzemiosła starożytnych i średniowiecznych budowniczych, ale również na dostrzeżenie różnorodności zaproponowanych rozwiązań konstrukcyjnych.

6

Recovery tread wheel pairs of machining

Ivanov I., Tarapanov A., Kononov D., Vorobev A.

Transport Problems

|

2013

|

T. 8, z. 1

105--112

EN

The basic methods of resurfacing wheels are determined and analised. It’s shown that for raising resource of used wheels and decreasing requirements of railway transport for new wheels it’s reasonable to use methods of recovering not only geometric parameters of rim, but also its mechanical properties. It’s marked that use of infeed profile high-speed grinding (VPVSh) enables to intensify significantly process of mechanical treatment of wheel rim profile both when its resurfacing in service and when manufacturing new wheel.

RU

Проанализированы основные методы восстановления колес. Показано, что для повышения ресурса использования колес и уменьшения потребностей железнодорожного транспорта в новых колесах разумно использовать методы восстановления не только геометрических параметров обода, но и его механических свойств. Отмечено, что использование врезного профильного высокоскоростного шлифования позволяет значительно улучшить процесс механической обработки профиля поверхности катания колеса при его эксплуатации и при изготовлении.

7

Electronic system for analyzing the electrical resistance of biological tissue in forensics

Manukova A., Ivanov I.

Elektronika : konstrukcje, technologie, zastosowania

|

2011

|

Vol. 52, nr 6

121-124

EN

In forensics there is a continuous development of new methods for analyzing the condition of the objects in order to improve the quality of the manipulations and operations as well as the accuracy of the conclusions made. Changing of the electrical resistance of tissues is an significant parameter that helps in pro per judgment of post-mortem changes of studied objects, based on the ability of tissue to be at the same time a conductor and a dielectric. Electrical and dielectric permittivity of an area is a complex function - on one hand are the parameters of influential currents and voltages together with their frequencies, and on the other hand is the physiological state of studied objects. The purpose of this article is to present an electronic system for testing the electrical resistance of tissue in running post-mortem changes, aiming to increase efficiency in the collection of objective evidences - that are applied to the medical expertise in forensics.

PL

W medycynie sądowej stale się rozwijają nowe metody analizy stanu obiektów bilogicznych w celu poprawy jakości wykonywanych zabiegów oraz zwiększenia dokładności wyników i wniosków. Zmiany rezystancji elektrycznej tkanek są zasadniczym wskaźnikiem, za pomocą którego można ocenić zmiany w badanych obiektach biologicznych po zgonie. Tkanki biologiczne mają jednocześnie właściwości elektryczne i dielektryczne. Przenikalność elektryczna tkanek jest złożoną funkcją przyłożonych napięć, płynących prądów i stanu fizjologicznego badanych obiektów. W artykule przedstawiono system elektroniczny do badania pośmiertnych zmian rezystancji elektrycznej tkanek biologicznych w celu przedstawienia obiektywnych dowodów jako załączniki do ekspertyzy w medycynie sądowej.