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1
Zarys historii hodowli i wystaw bydla simentalskiego w Polsce
100%
Kajzer A.
Krośnieński Magazyn Rolniczy
|
1994
|
nr 06
4-5
2
Wpływ modyfikacji powierzchni tytanu (Grade 4) oraz stopu Ti6Al7Nb na zwilżalność i energię powierzchniową
63%
Kajzer A. , Dydlińska K.
|
|
tom R. 61, nr 5
217--220
PL
W pracy przedstawiono wyniki badań chropowatości, zwilżalności oraz energii powierzchniowej tytanu (Grade 4) oraz stopu Ti6Al7Nb o zróżnicowanej modyfikacji powierzchni. Odpowiednio przygotowane próbki poddano szlifowaniu na papierze o ziarnistości 1200, polerowaniu mechanicznemu zawiesiną diamentową i jako etap końcowy zawiesiną SiO2. Następnie podzielono je na grupy i część z nich dodatkowo poddano sterylizacji parowej oraz 28-dniowej ekspozycji na roztwór Ringera. Do badań wykorzystano profilometr stykowy Surtronic 3+ firmy Tylor&Hobson i goniometr SURFTENS UNIVERSAL firmy OEG. Na podstawie przeprowadzonych badań stwierdzono różnice w wartościach chropowatości oraz zwilżalności i energii powierzchniowej w zależności od badanej powierzchni. Uzyskane wartości należą do grupy wyznaczanych parametrów, które są istotne podczas doboru sposobu przygotowania powierzchni do zastosowań na implanty zarówno ortopedyczne, jak i stomatologiczne.
EN
The study presents the results of surface roughness, wettability and surface free energy of titanium (Grade 4) and T/6AI7Nb alloy of various surface modification. Properly prepared samples were submitted to grinding on paper grit 7200, mechanical polishing using slurry of diamond and as a final step Si02 suspension. Afterwards samples were divided into groups and some of them additionally subjected to steam sterilization and 28 day exposure to Ringer's solution. The profilometer Surtronic 3+ of Taylor & Hobson and goniometer SURFTENS UNIVERSAL by OEG were used in the studies. Based on the study there were differences in the values of roughness and wettability and the surface free energy depending on the test surface. The values obtained are the group of determined parameters, which are important in the selection of surface preparation for use for both the orthopedic and dental implants.
3
Content available Własności mechaniczne udowych kości bydlęcych o różnym stopniu uwodnienia
63%
Szamatowicz B. , Kajzer A.
Aktualne Problemy Biomechaniki
|
2016
|
tom z. 10
75--80
PL
Celem pracy było określenie własności wytrzymałościowych bydlęcych kości udowych o różnym stopniu uwodnienia. Podczas realizacji pracy przeprowadzono statyczną próbę trójpunktowego zginania oraz statyczną próbę jednoosiowego ściskania. W konsekwencji wyznaczono wartości wytrzymałości na zginanie oraz ściskanie wszystkich grup badawczych. Stwierdzono, że zarówno stopień uwodnienia, jak i kierunek pobierania próbek znacząco wpływa na wartości własności wytrzymałościowych.
EN
The aim of the study was determinate the mechanical properties of femoral bovine bones with varying degrees of hydration. During the execution of the work conducted the static three-point bending test and a static uniaxial compressive test. Consequently, were determine the values of bending strength and ultimate compressive strength for the all research groups. It was stated that the degree of hydration and direction of sampling significantly alters the studies strength parameters.
4
Wyszukiwanie dokładne i przybliżone ciągów tekstowych z wykorzystaniem transformaty Burrowsa Wheelera
63%
Kajzer A. , Pokrzywa R.
Studia Informatica
|
2012
|
tom Vol. 33, nr 1
77-89
PL
Niniejszy artykuł przedstawia sposoby rozwiązywania problemu wyszukiwania dokładnego i przybliżonego ciągów tekstowych z wykorzystaniem transformaty Burrowsa-Wheelera. Omówione zostało także działanie skompresowanych indeksów pełnotekstowych, dzięki którym algorytmy wyszukiwania tekstu moŹgą działać w ograniczonej przestrzeni. Głównymi strukturami danych, które zostały opisane w tekście, są Wavelet Tree oraz Bi-directional Burrows-Wheeler Transform.
EN
This paper describes how the problem of exact and approximate string matching can be resolved using Burrows-Wheeler Transform. The paper considers how compressed full-text indexes work and allow string matching algorithms to operate in a limited space. Two main data structures presented in the text are Wavelet Tree and Bi-directional Burrows Wheeler Transform.
5
Badania własności fizykochemicznych płytki kątowej ze stali 316L
63%
Kajzer A. , Antonowicz M.
Hutnik, Wiadomości Hutnicze
|
2016
|
tom Vol. 83, nr 7
302--304
PL
W artykule przedstawiono wyniki badań własności mechanicznych i fizykochemicznych płytki kątowej do leczenia złamań międzykrętarzowych, wykonanej ze stali 316L odpornej na korozję w stanie umocnionym o powierzchni polerowanej elektrochemicznie i pasywowanej chemicznie. Płytka została usunięta z organizmu po 18 miesiącach. Analizowano wpływ ilości uszkodzeń mechanicznych powierzchni na chropowatość oraz odporność na korozję wżerową. Na podstawie uzyskanych wyników stwierdzono, że w miejscach o licznych uszkodzeniach mechanicznych powierzchni, wartości parametru Ra przekraczają 0,16 μm. Wpływa to na obniżenie odporności korozyjnej w tych obszarach w odniesieniu do powierzchni nieuszkodzonych.
EN
The paper presents results of mechanical and physicochemical properties of the angular bone plates, made of cold-worked 316L stainless steel, electrochemically polished and chemically passivated designed for the treatment of intertrochanteric fractures. The plate was removed from the body after 18 months. The influence of mechanical surface damage on roughness and pitting corrosion resistance were analyzed. It has been found based on the obtained results that in areas with mechanically damaged surface the Ra parameter exceed 0.16 μm. This affects the decrease in pitting corrosion resistance in these areas in relation to the unaffected surfaces.
6
Content available Application of the Lattice Boltzmann Method to the flow past a sphere
63%
Kajzer A. , Pozorski J.
Journal of Theoretical and Applied Mechanics
|
2017
|
tom Vol. 55 nr 3
1091--1099
EN
The results of fully resolved simulations and large eddy simulations of bluff-body flows obtained by means of the Lattice Boltzmann Method (LBM) are reported. A selection of Reynolds numbers has been investigated in unsteady laminar and transient flow regimes. Computed drag coefficients of a cube have been compared with the available data for validation purposes. Then, a more detailed analysis of the flow past a sphere is presented, including also the determination of vortex shedding frequency and the resulting Strouhal numbers. Advantages and drawbacks of the chosen geometry implementation technique, so called “staircase geometry”, are discussed. For the quest of maximum computational effi- ciency, all simulations have been carried out with the use of in-house code executed on GPU.
7
Content available remote Badania potencjodynamiczne i impedancyjne implantów do leczenia zniekształceń przedniej ściany klatki piersiowej
63%
Kajzer W. , Kajzer A.
Przegląd Elektrotechniczny
|
2013
|
tom R. 89, nr 12
275-278
PL
Celem pracy była ocena odporności korozyjnej implantów do leczenia zniekształceń przedniej ściany klatki piersiowej w stanie wyjściowym oraz po określonym czasie przebywania w organizmie człowieka. W szczególności analizowano wpływ uszkodzeń mechanicznych powierzchni implantów powstałych na wskutek ich przedoperacyjnego modelowania na własności korozyjne. Badania przeprowadzono w roztworze Ringera symulującym płyny ustrojowe człowieka.
EN
The aim of the paper was to evaluate the pitting corrosion of the implants used in the treatment of anterior deformity of chest in the initial state and after given time of presence in the human’s organism. In particular the analysis focused on the influence of mechanical damage of the implants surface arisen as a result of preoperative modeling on corrosion properties. The research was conducted in Ringer's solution which simulates human's body fluids.
8
Makroregionalna Wystawa Zwierzat Hodowlanych
63%
Kajzer A. , Stopyta R.
|
|
nr 09
6-8
9
Bieszczadzkie sympozjum
63%
Kajzer A.
Chów Bydła
|
1996
|
tom 39
|
nr 07
5
10
Content available Physicochemical Properties of Silicon Cast Iron
51%
Stawarz M. , Kajzer W. , Kajzer A. , Dojka M.
Archives of Foundry Engineering
|
2017
|
tom Vol. 17, iss. 2
101--106
EN
The article presents results of pitting corrosion studies of selected silicon cast irons. The range of studies included low, medium and high silicon cast iron. The amount of alloying addition (Si) in examined cast irons was between 5 to 25 %. Experimental melts of silicon cast irons [1-3] were conducted in Department of Foundry of Silesian University of Technology in Gliwice and pitting corrosion resistance tests were performed in Faculty of Biomedical Engineering in Department of Biomaterials and Medical Devices Engineering of Silesian University of Technology in Zabrze. In tests of corrosion resistance the potentiostat VoltaLab PGP201 was used. Results obtained in those research complement the knowledge about the corrosion resistance of iron alloys with carbon containing Si alloying addition above 17 % [4-6]. Obtained results were supplemented with metallographic examinations using scanning electron microscopy. The analysis of chemical composition for cast irons using Leco spectrometer was done and the content of alloying element (silicon) was also determined using the gravimetric method in the laboratory of the Institute of Welding in Gliwice. The compounds of microstructure was identify by X-ray diffraction.
11
Content available remote FEM analysis of expandable intramedullary nails in healthy and osteoporotic femur
51%
Kajzer W. , Kajzer A. , Marciniak J.
Journal of Achievements in Materials and Manufacturing Engineering
|
2009
|
tom Vol. 37, nr 2
563-570
EN
Purpose: The paper presents the results of numerical analysis of expandable intramedullary nail – femur system in different states of healing. The aim of the research was to determine displacements, deformations and stresses occurring in a bone depending on the age of the patient and the extent level of osteoporosis. Design/methodology/approach: A femur was selected to numerical analysis. The analysis concerned the influence of the load and torsion of the system on the obtained results of displacements, deformations and reduced stresses. In order to make calculations, four models with different mechanical properties were chosen: model 1: femur with mechanical properties corresponding with a femur of a patient at the age of 16, model 2: with mechanical properties corresponding with a femur of a patient at the age of about 28, model 3: with mechanical properties corresponding with a femur of a patient at the age of about 20 and at the age of 50 to 65 years old and model 4: with mechanical properties corresponding with a femur of a patient at the age above 70 or with osteoporosis. For the chosen model of intramedullary nail, mechanical properties of titan alloy Ti-6Al-4V were used. Two load steps were analyzed: load step 1 in which simple axial load with a value ranging from 250 up to 1000 N simulating patient standing on one leg was used, and load step 2 – a torsion analyzing loads that the nail is exposed to while walking. Findings: Conducted analysis of the system showed the difference in displacements, deformations and reduced stresses depending on assumed mechanical properties of femur and load step of the system. Research limitations/implications: The limitations were connected with the necessity of simplifying the assumptions, which were associated with limitations caused by boundary conditions. In researches 4 forces loading the femur axially were used: 1: force F = 250N, 2: with force F = 500N, 3: with force F= 750N and 4: with force F = 1000N and 5 values of angle displacement of the femur head were assumed: 1: angle displacement ö = 1°, 2: ö = 5°, 3: ö = 10°, 4: ö = 15°, 5: ö = 20°. Practical implications: Obtained results can be applied in selection of stabilization methods of bone fragments and in forecasting biomechanical conditions depending on the age of patient and the state of his general conditions of bones. Originality/value: The paper presents the displacement-deformation-stress characteristics of femur - expandable intramedullary nail system, using the Finite Elements Method (FEM) in the analysis.
12
Content available remote Expandable intramedullary nail – experimental biomechanical evaluation
51%
Kajzer A. , Kajzer W. , Marciniak J.
Archives of Materials Science and Engineering
|
2010
|
tom Vol. 41, nr 1
45-52
EN
Purpose: The paper presents results of experimental analysis of femur and femur - expandable intramedullary nail system. The aim of the work was to determine displacement in three models. In addition, the torsion of the system aiming at determining the moments depending on the torsional angle of the bone was carried out. Design/methodology/approach: Three femurs were selected for studies. The analysis was carried out on the femur - expandable intramedullary nail system. The influence of the loads and displacements on the bone - nail system on the results of experimental analysis was analysed. In order to carry out calculations, three models were selected: model I - bone without fracture gap, model II and III - femur with expansion intramedullary nails - fracture gap was located 100 mm under greater trochanter. The studies were performed on femur models produced by Swedish company Sawbones. The intramedullary "Fixion IM" nails (Ti-6Al-4V alloy) were implanted into the bone. Displacements of determinated models were being recorded from the sensors every 100 N from 10 N to 2000 N. Findings: The analyses showed the difference in displacements, depending on the selected models. Research limitations/implications: The limitations were connected with simplification of boundary conditions during analysis which were the result of the simplification of the models. While studying, muscles and ligaments supporting the bone in anatomic position were not taken into consideration. Instead, the system has been loaded with the axial force (compression). Practical implications: The obtained results can be useful in clinical practice. They can be applied in selection of stabilization methods or rehabilitation as well as in describing the biomechanical conditions connected with type of bone fracture obtained from medical imaging. Originality/value: . The work compares the values of displacement of characteristic points of femur (healthy - model I) with the femur - expandable intramedullary nail system (models II and III) with the applied force. In order to estimate the value of the torsional angle of the upper part in relation to the lower one depending on the applied force, the torsion of the model was conducted. On this basis, it was indicated a maximum moment in which the nail would not become loose in medullar canal.
13
Content available Biomechanical analysis of plates used for chest treatment
51%
Kajzer A. , Kajzer W. , Marciniak J. , Pilecki Z.
Engineering of Biomaterials
|
2018
|
tom Vol. 21, no. 148
26
14
Content available remote Biomechanical analysis of the intervertebral disc implant using the finite element method
51%
Kajzer W. , Kajzer A. , Pindycki I.
|
|
tom Vol. 15, nr 3(45)
57--66
EN
Dysfunctions of the vertebral column belong to a group of civilisation diseases and they affect approximately 80% of population. The underlying cause is modern (sedentary) lifestyle, low locomotive activity of people and frequent motor vehicle and sports accidents. Despite civilisation’s progress, no injury prophylactics or prevention of dysfunctions of the vertebral column have been introduced. The key element influencing function of the vertebral column is the intervertebral disc. It enables multidimensional movements and constitutes a basic connective element between the joints of the vertebral column. It also enables performing basic daily activities. Acting as a “damper”, it cushions vibrations and transmits loads between the vertebrae. One of the diseases affecting the intervertebral disc is discopathy. This is the most common degenerative disease, which can be treated by both conservative and surgical treatment. After removal of the damaged disc, it can be replaced by an adequate implant, which will assume its function. The implant will be expected to restore the vertebral column motor function, as well as to eliminate the pain resulting from compression of the spine caused by the damaged disc. This paper presents a biomechanical analysis using the finite element method for the L2-L3 vertebrae system with natural intervertebral disc, and the L2-L3 – implant of the intervertebral disc system. Two cases of the system vertebrae-implant were analysed which differed in the placement of the artificial disc in the intervertebral space. Within the conducted analysis, the state of displacement, strain and stress of reduced analysed systems and their individual elements was determined. A comparative analysis of the results and calculations was performed, also conclusions and observations were formulated, constituting a starting point for building more advanced calculation models and further analyses of such implants.
15
Characterization of quasi-static behavior of honeycomb core sandwich structures
51%
Katunin A. , John M. , Joszko K. , Kajzer A.
|
2014
|
tom T. 22, nr 53
78--84
EN
Honeycomb core sandwich composite structures gained their popularity in aircraft, aerospace, automotive and naval industries mainly due to their superior flexural stiffness and very low mass, which cause that their application in engineering constructions becomes very attractive. Since they contain core and face sheets made of different materials with different properties their behavior under quasi-static loading is highly nonlinear and the forcedisplacement response contains characteristic zones caused by various mechanical phenomena. The characterization of such behavior under tensile and bending loading as well as characterization of failure mechanisms accompanied with quasi-static loading is the main goal of this paper. Obtained experimental results and their analysis allow for better understanding of occurred phenomena in such structures, which can be helpful during modeling of elements made of such sandwich composites as well as prediction of their behavior under various loading conditions.
PL
Kompozyty przekładkowe z rdzeniem o strukturze plastra miodu zyskały swoją popularność w przemyśle lotniczym, kosmicznym, samochodowym oraz okrętowym głównie dzięki swojej wyjątkowej sztywności oraz bardzo niskiej masie, co spowodowało że ich wykorzystanie w konstrukcjach inżynierskich stało się bardzo atrakcyjne. Biorąc pod uwagę fakt, że rdzeń i okładziny wykonane są z różnych materiałów o różnych właściwościach zachowanie tych struktur pod wpływem obciążeń quasi-statycznych jest wysoce nieliniowe, a odpowiedź siła-przemieszczenie zawiera charakterystyczne obszary spowodowane różnymi zjawiskami mechanicznymi. Charakteryzacja takiego zachowania podczas obciążeń rozciągających i zginających oraz mechanizmów zniszczenia towarzyszących obciążeniom quasi-statycznym jest głównym celem tej pracy. Otrzymane wyniki eksperymentalne i ich analiza pozwalają na lepsze zrozumienie zachodzących zjawisk w takich strukturach, co może być przydatne przy modelowaniu elementów wykonanych z kompozytów przekładkowych, jak również predykcji ich zachowania przy różnych warunkach obciążenia.
16
Program hodowlany bydla rasy simentalskiej z otwartym centrum genetycznym
51%
Hetman T. , Kajzer A. , Draus S.
|
1993
|
tom 61
|
nr 02
11-12
17
Content available Studies of the Corrosion Resistance Properties of Bone Screws Made from 316L Stainless Steel in Ringer's Solution
51%
Kajzer A. , Antonowicz M. , Ziębowicz B.
|
|
tom Vol. 63, iss. 1
323--328
EN
Stainless steel 316L is one of the most common metallic biomaterials used for implants. Its passive surface provides a good corrosion resistance in the body environment, which can be reduced by surface mechanical damages. This is the reason why the bone screws made of stainless steel 316L were subjected to laboratory analysis in the initial state, after diversified implantation period and after mechanical damage of the surface. The mechanical damages were estimated on the basis of stereoscopic and scanning electron microscope (SEM). In order to estimate the pitting and crevice corrosion resistance, potentiodynamic and potentiostatic examinations were performed. On the basis of obtained results it can be stated that despite the visible damages on the surface, the investigated screws present a good pitting corrosion resistance. However, the way the screws were fastened caused frictional corrosion and existing cavities led to crevice corrosion. Moreover, clear correlation between magnitude of mechanical damages of the surface, implantation time and screws corrosion resistance was observed.
18
Content available remote Biomechanical analysis of the femurDynamic Condylar Screw (DCS) system
51%
Kajzer W. , Kajzer A. , Antonowicz M.
Archives of Materials Science and Engineering
|
2016
|
tom Vol. 79, nr 1
19--26
EN
Purpose: The aim of this study was a biomechanical evaluation of the (Dynamic Condylar Screw - DCS) system after epicondyle fractures and a comparison of obtained results of the two alternative biomaterials for the stabilizer. Design/methodology/approach: Models of stabilizer and femur were designed, the discretization was conducted and boundary conditions were set. Numerical analysis with the use of the finite element method was performed in the ANSYS Workbench 15 Software. Two models of system: M-316 LVM (stabilizer with properties CrNiMo steel - femur) and M-Ti64 (stabilizers with properties Ti6Al4V alloys – femur) were subjected to numerical analysis. As a reference point the state of displacement, strain and von Misses stresses by in helfy femur (M-HF) were determined. Findings: For all of the analysed models, the values of assumed mechanical properties of cortical bone and cancellous bone were not exceeded. Simultaneously, it is possible to use alternative biomaterials, CrNiMo steel or Ti6Al4V alloy for DCS system. Research limitations/implications: In order to perform more detailed characteristics of analysed DCS implant, in future research it is expected to carry out macro and microscopic observations for implants removed from the body and their electrochemical evaluation. Practical implications: The analysis allows the determination of potentially dangerous areas, affected to damage due to overloading. Furthermore, the analysis identifies the areas of initiation and development of crevice, pitting and fatigue corrosion. Originality/value: The presented work allows the selection of alternative metallic biomaterials for the manufacturing of the evaluated DCS system and indicates its potentially dangerous area. This work might be interesting for engineers and doctors dealing with the construction of a new forms of implants used in orthopedics.
19
Content available remote FEM analysis of compression screws used for small bone treatment
51%
Kajzer W. , Kajzer A. , Marciniak J.
Journal of Achievements in Materials and Manufacturing Engineering
|
2009
|
tom Vol. 33, nr 2
189-196
EN
Purpose: The paper presents results of numerical analysis in metatarsal bone „I” - compression screws system. The aim of the work was determined stresses, strain and displacement in the inserted screws. Design/methodology/approach: Metatarsal bone „I” was selected to researches. The analysis was carried out on the metatarsal bone „I” - compression screws system. The influence of the loads and displacements on the bone - screws system on the results of numerical analyses was analyzed. In order to carry out calculations, 2 models of diverse mechanical properties of screw - Ti-6Al-4V alloy - model 1, stainless steel (Cr-Ni-Mo) - model 2 and two load steps were selected. Findings: The analyses showed the difference in displacements, strains and stresses depending on the selected mechanical properties screws and the way of loads. Research limitations/implications: The limitations were connected with simplification of numerical model of femur as well as with the selected boundary conditions. Two difference way of loads metatarsal bone „I” - compression screws system: 1_force F = 500 N, 2_ displacement l = 1 mm were applied. Practical implications: The obtained results can be useful in clinical practice. They can be applied in selection of stabilization methods or rehabilitation as well as in describing the biomechanical conditions connected with type of bone fracture obtained from medical imaging. Originality/value: Stress-strain-displacement characteristics of metatarsal bone „I” - compression screws system, obtained from the numerical analysis were presented in the work.
20
Content available Osteosynteza śródszpikowa gwoździami rozprężnymi
51%
Kajzer A. , Kajzer W. , Marciniak J.
Engineering of Biomaterials
|
2008
|
tom Vol. 11, no. 77-80
74--76
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