In order to enhance bioactive properties of titanium 99.2 used in implantology and various biomedical applications, numerous methods to form tight oxide coatings are being investigated. Some of these interesting techniques for generating TiO2 coatings include: electrochemical methods with anodizing, electric discharge treatment, plasma methods (PVD) and diffusive methods (i.e. oxidation in a fluidized bed). Each method aims to create a thin homogenous oxide coating characterized with thermal stability and repassivation ability in the presence of body fluid environment. However, new methods are still sought for increasing the biocompatibility of the substrate following a change in the intensity of depositing on the oxide coating compounds with high biocompatibility with body tissues, including hydroxyapatite, which constitutes the basis for subsequent osseointegration processes. The article presents investigation of HAp formation on titanium substrate surface after hybrid oxidation process. Hybrid surface treatments combine methods of fluidized bed atmospheric diffusive treatment FADT with the PVD surface treatment realized with different parameters (FADT – 640°C / 8h and PVD – magnetron sputtering with TiO2 target). In order to investigate the effects of hybrid oxidation and the formation of HAp molecules, SEM-EDS, SEM-EBSD, STEM-EDS, RS, nanoindentation and Kokubo bioactivity tests (c-SBF2) were carried out. The hybrid method of titanium oxidation, proposed by the Author, presents a new outlook on the modification and development of the properties of oxide coatings in the area of biomedical applications. Combining the ways of Ti Grade 2 oxidation in the hybrid method highly improves the formation of hydroxyapatite compounds and shows the potential of applying such a technique in implantology, where the intensive growth of bone tissues is crucial.
The paper presents research of metallic glass based on a Mg72Zn24Ca4 alloy. Metallic glass was prepared using induction melting and further injection on a spinning copper wheel. The X-ray diffractometer and differential scanning calorimeter (DSC) were used to investigate the phase transformation of the amorphous ribbon. The heat released in the crystallization process, during isothermal annealing, based on the differential scanning calorimeter investigation, was determined to be 166.18 Jg-1. The effect of isothermal annealing temperature on the kinetics of the amorphous alloy crystallization process using differential scanning calorimeter was investigated. For this purpose, two isothermal annealing temperatures were selected. The incubation time decreases as the temperature of the isothermal annealing increases from 300 to 252 seconds. The same relationship is visible in the case of duration of the phase transformation, which also decreases as the temperature of the isothermal annealing increases from 360 to 228 seconds. The obtained results show a significant influence of isothermal annealing temperature on the degree of phase transformation.
Heat treatment processes, due to qualitative requirements for the cast machinery components and restrictions on energy consumption resulting on the one hand from environmental concerns, and on the other hand from a requirements coming from minimization of manufacturing costs, are resulting in searching after a technologies enabling obtainment of satisfactory results, in form of improved mechanical properties mainly, while minimizing (limiting) parameters of successive operations of the heat treatment. Heat treatment of the T6 type presented in this paper consists in operations of heating of investigated alloys to suitably selected temperature (range of this temperature was evaluated on the base of the ATD method), holding at such temperature for a short time, and next rapid cooling in water (20 oC) followed by artificial ageing, could be such technology in term s of above mentioned understanding of this issue. Performed T6 heat treatment with limited parameters of solutioning operation resulted in visible increase in tensile strength Rm of AlSi7Mg, AlSi7Cu3Mg and AlSi9Cu3(Fe) alloys.
We propose an approach to indirectly learn the Web Ontology Language OWL 2 property characteristics as an explanation for a deep recurrent neural network (RNN). The input is a knowledge graph represented in Resource Description Framework (RDF) and the output are scored axioms representing the characteristics. The proposed method is capable of learning all the characteristics included in OWL 2: functional, inverse functional, reflexive and irreflexive, symmetric and asymmetric, transitive. We report and discuss experimental evaluation on DBpedia 2016-10, showing that the proposed approach has advantages over a simple counting baseline.
The effect of laser processing on the structure, microstructure and hardness of high-speed steel produced by powder metallurgy was investigated. The samples were surfaces remelted with impulse CO2 laser radiation under different operation conditions. In the remelted layer, the presence of full remelting, partial remelting and heat affected zones was detected. As a result of concentrated laser beam treatment, microstructures characteristic of the rapid crystallization process were observed. The microstructure in the full remelting zone was characterized by a fine microdendritic structure with the average distance between the secondary axes of dendrites below 1 µm and the dissolution of primary carbides. Retained austenite was found in the remelted samples, the amounts of which depended on the treatment parameters and grew with an increase in the speed of the laser beam movement. There was no unequivocal effect of the distance of the irradiated surface from the focus of the beam focusing system on the content of retained austenite. Due to the presence of retained austenite in the remelted part, the hardness decreased by about 23% compared to the hardness of the material before the treatment. On the other hand, laser processing leads to strong refinement of the microstructure and eliminates the residual porosity of powder steels, which can increase the toughness and cutting performance of steel. The research also showed the possibility of shaping the geometry of the remelting zone by the appropriate selection of machining parameters
The paper presents an analysis of the behaviour of bent reinforced concrete beams strengthened with CFRP laminates fixed with adhesive before and after unloading, and more importantly, an analysis of the work of reinforced concrete beams strengthened with pre-stressed CFRP laminates fixed with adhesive. The analyses were based on a moment-curvature model prepared by the author for reinforced concrete beams strengthened under load with pre-stressed CFRP laminates. The model was used to determine the effect of compression with CFRP laminates and their mechanical properties on the effectiveness of strengthening the reinforced concrete beams analysed in this study.
Civil engineering is one of the many fields of occurrences of uncertain parameters. The present paper in an attempt to present and describe the most common methods used for inclusions of uncertain parameters . These methods can be applied in the area of civil engineering as well as for a larger domain. Definitions and short explanations of methods based on probability, interval analysis, fuzzy sets, and convex sets are presented. Selected advantages, disadvantages, and the most common fields of implementation are indicated.
An example of a cantilever beam presented in this paper shows the main differences between the methods. Results of the performed analysis indicate that the use of convex sets allows us to obtain an accuracy of results similar to stochastic models. At the same time, the computational speed characteristic for interval methods is maintained.
The main objective of the article is to present quantified and measurable risks likelihood appearance, impact and significance of inspected and monitored 48 commercial construction projects and their feasibility to be carried out. Original technical, financial and organisational feasibility studies in compliance with a rigorous Bank Investment Supervision requirements have been executed by the author in the period of 2005–2018. Methodology of construction project appraisal for financing and execution professional preparation have been laid out – technical documentation, arrangements, realisation. Analysis and assessment of Bank Investment Supervision consisted of project execution plan PEP, geotechnical and environmental conditions, permit design, agreements and decision impacts of local authorities, engineering contract for construction works, project insurance and performance bonds, schedule of execution tasks and their costs, payment plan, investment budget and project economical effectiveness, scope of monthly construction works execution assessed by Earned Value Method approach and handover procedure of construction project. An attempt was made to express numerically the relationship between risks impacts and their level of likelihood. Also, a method of associating the influence of projects risks impacts on the extent of the likelihood of project risk occurrence which makes possible to determine the direction and the strength of this relationship was presented. Finally, risks likelihood appearance, impact and significance variability of commercial construction projects within last two years of booming investment industry have been determined.
The aim of the study was to develop a practical approach to parametric shaping of spatial steel rod structures formed based on a hyperbolic paraboloid. This design approach was realized by application of designing tools working in environment of Rhinoceros 3D, that is its plug-in Grasshopper for geometric modelling and Karamba 3D for structural analysis. The goal of this research was to elaborate an universal scripts in order to create rod structures‘ models of various forms and grid patterns, as well as evaluating their structural behaviour dependently on various boundary conditions. The optimisation criterion was the minimum mass and deflection. Several proposals of coverings by means of single layer grid structures were presented and analysed to choose the best solution. The rod structures generated based on a hyperbolic paraboloid turned out to be structures with good static properties, so may be an interesting proposals to cover large areas.
A group of old apartment houses with the age over 100 years (that is those carried out before the First World War) takes an important place in polish building resources. Technical maintenance of apartment houses, traditional methods erected, is nowadays and will be a valid problem in the nearest future. The results of the work refer to the general population, estimated for 600 objects, that is about 20% of municipal downtown apartment houses in Wrocław.
The purpose of the research was to identify an influence of widely considered maintenance of apartment houses on a degree and intensity of their elements’ deterioration. The goal of the work has been fulfilled by symptoms’ analysis of declining of inspected elements’ exploitation values, that is identification of mechanics of their defects arising.
The range of the work has required creation of original qualitative model of pinpointed defects and its transfer into quantitative one. It has made possible to analyse the reason - effect phenomena „defect - technical wear” relevant to the most important elements of Wroclaw downtown district’s apartment houses. The research procedure has been conducted in accordance of fuzzy sets theory which made possible to describe qualitative model of pinpointed defects and its transfer into a quantitative one.
The article discusses the dangers arising from construction disasters. This phenomenon is the most serious effect of the risk that may occur in construction. I presented this on the basis of an analysis of all construction disasters that have taken place in Poland in the last twenty years. I made a detailed analysis of the events that occurred during the maintenance of building facilities, taking into account the reasons for their occurrence and the effects they cause. The aim of this analysis is to identify areas of risk in order to eliminate the hazard and, as a consequence, take appropriate actions to counteract this type of events. Unfortunately, one should be aware that despite technical progress building disasters cannot be completely avoided in our surrounding, but one must use the knowledge acquired on this basis to minimize their number.
The paper presents a comprehensive look at the perspectives on the use of THz in digital communication systems. The publication aims to focus on arguments that justify a significant increase in the frequency of radio links and their integration with fibre-based networks. Comparison of THz links with their microwave and optical counterparts is discussed from basic physical limitations to technological constraints. Main attention is paid to the available channel capacity resulting from its bandwidth and signal-to-noise ratio. The short final discussion is about technology platforms that seem to be crucial to the availability of suitable THz sources. According to the author, the biggest advantage of using bands in the range of several hundred GHz for a digital data transmission is their use for mobile communication over short distances, as well as for broadband indoor links. However, these applications require a development of compact electronic THz sources with low noise and power reaching single watts. This is beyond the range of the most popular silicon-based technology platform, although a significant progress can be expected with the development of technologies based on wide bandgap semiconductors. Fibre optic connections remain the unquestioned leader in communication over long distances and permanent links.
An efficient operation of a Ho:YLF laser pumped by a Tm-doped fibre laser is reported. The research in a continuous-wave (CW) operation was done for two crystals of the same 0.5 at.%Ho dopant concentration and with different lengths (3×3×30 mm3 and 3×3×50 mm3). For an output coupling transmission of 20% and a crystal length of 50 mm, the maximum CWoutput power of 38.9 W for 81.4 W of incident pump power, corresponding to the slope efficiency of 52.3% and optical-to-optical conversion efficiency of 47.8% (determined with respect to the incident pump power) was achieved. The highest opti- cal-to-optical conversion efficiency of 70.2% with respect to the absorbed pump power was obtained. The influence of a heat-sink cooling water temperature on theCWlaser performance was studied. For a Q-switched operation the pulse repe- tition frequency (PRF) was changed from 2 to 10 kHz. The maximum average output power of 34.1 W at the PRF of 10 kHz was obtained for a 50 mm holmium crystal length. For 2 kHz PRF and 71.9 W of incident pump power, pulse energies of 13.7 mJ with a 21 ns FWHM pulse width corresponding to 652 kW peak power were recorded.
Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabolite, dichlorodiphenyldichloroethylene (DDE) can disturb the secretory function of the ovary and both contractions and secretory function of the uterus during the estrus cycle and pregnancy. Additionally, PCBs can pass through the placental barrier into allantoic and amniotic fluid. The presence of PCBs in these fluids is associated with higher frequency of spontaneous abortions and premature births in humans and animals. Therefore, the effect of PCBs, DDT and DDE on the connexins (Cx26, Cx32 and Cx43) and keratin 8 (KRT8) expression in bovine placentomes was investigated. The placentome slices from the second trimester of pregnancy were incubated with PCB153, 126, 77, DDT and DDE (each at doses of 1, 10 or 100 ng/ml) for 48 h. Then, the slices were stained using immunohistochemistry. The density of Cxs staining was measured with Axio- Vision Rel. 4.8 software in fetal-maternal connections and binuclear cells (BNC). None of the tested xenobiotics (XBs) affected the localization of Cxs and KRT8 in the fetal-maternal connection area, but the XBs affected the density of Cxs in fetal-maternal connections and binuclear cells (BNCs). Depend on the doses, in fetal-maternal connections all used PCBs changed the protein expression of different Cxs, while in BNCs, all tested XBs except DDT increased the expression of Cxs. None of investigated XBs affected on KRT8 expression. In summary, used XBs affect the expression of Cxs and change the quantitative relationships between them. Therefore, XBs can unfavorably influence function of the utero-placental barrier in cows.
Construction and demolition (C&D) waste management should be accordance with the waste management hierarchy. In practice, C&D waste are often downcycling. It is the result of many factors, including lack of awareness about the value inherent in waste. The paper presents analysis of the adaptability of non-destructive testing (NDT) methods for technical assessment of waste properties. As part of the work, non-destructive testing methods were described and classified in accordance with material and the features they enable testing. The publication presents examples of the use of NDT in the recovery of building materials during construction projects, in the field of influence of technical information of waste on the way it is managed. Finally, a scheme of waste management process during the renovation of an object with the application of NDT methods was presented.
Elaborating composites containing waste materials requires study of basic mechanical properties and assessment of their structure quality. The subject of investigation was PPC concrete where aggregate was substituted with PET remaining after beverages bottles grinding. Substitution was done up to 25% (by volume). Waste material was fractioned and applied in various granulations. The main goal was to indicate the influence of such modification on the composite mechanical properties and to examine composite structure quality at macro level. Since PET and quartz differ greatly in density, to perform such examination it was possible to apply the nondestructive ultrasonic method, one of the most common NDT techniques used in material science and industry. The paper presents the effects of substitution of quartz with PET on ultrasonic wave propagation in PCC. The ultrasonic test results (measurements of wave velocity) compared with results of destructive tests (flexural and compressive strength) showed great correlation.
The main purpose of the study is to investigate the mechanical properties around an underground gas storage cavern in bedded salt rock. Firstly, considering the characteristics of the salt rock formation in China, the mechanical model was simplified into a hollow cylinder, which containing non-salt interlayer. In terms of elastic theory, Love displacement function was developed, and the elastic general solution of stress and deformation components were obtained after determining the undetermined coefficients. Under the same condition, numerical simulation was carried out. The validity of the elastic general solution is verified by comparing to numerical simulation results. Furthermore, Based on the feasible general elastic solution, viscoelastic solution was obtained through Laplace transformation and inverse Laplace transform, which could provide reference for the study on the stability and tightness of underground gas storage carven during operation to some extent.
Due to the unrecognized effect of tigecycline (TIG) on CD4+ and CD8+ T cells, the present study has been undertaken in order to determine whether the drug can affect these cells in respect of their counts, and the production of IFN-γ, IL-17 (pro-inflammatory and immune-protective cytokines), IL-4 (anti-inflammatory and immune-protective cytokine), IL-10 and TGF-β (anti-inflammatory and immune-suppressive cytokines). Murine lymphocytes were treated with TIG for 48 and 96 h at concentrations reflecting its plasma levels obtained in vivo at therapeutic doses, and at 10-fold lower concentrations. It was found that TIG neither affected substantially the percentage and absolute counts of entire CD4+ and CD8+ T cell populations nor influenced the Foxp3+CD25+CD4+ regulatory/suppressive T cell subset. Furthermore, the percentages of IL-4-, IL-10-, IL-17- and TGF-β-producing CD4+ T cells were not altered following the exposure to TIG. Similarly, TIG did not influence IFN-γ production by CD8+ T cells. Thus, with respect to the parameters evaluated, TIG does not seem to exert immune-suppressive and anti-inflammatory effects.
The aim of the study was to develop new laparoscopic technique for repeated recovery of sheep oocytes. Oocytes were aspirated with specifically designed catheter. It allowed to recover oocytes without ovary damage and to preserve very good quality of recovered oocytes. Fifteen ewes were oocytes donors. Oocytes were collected: one time (group I, n=15), two times (group II, n=15), three times (group III, n=10), four times (group IV, n=5). The endoscope was inserted into the abdominal cavity. Two trockars for putting the manipulators were inserted 15 cm cranial from the udder. Oocytes were collected by aspiration of the follicular fluid from the ovarian follicles. The observed clinical complications were: ovary bleeding and cicatrix at place of needle insertion, the fragmentary adhesion of infundibulum and ovary, adhesions of omentum and peri- toneum near the place where the grasping forceps were inserted and adhesion of ovary and uterus. Ovarian follicles (n=204) were aspirated, 130 (63.8%) oocytes were obtained. Out of 130 obtained oocytes, 112 were qualified for in vitro maturation. The remaining 18 oocytes (13.8%) were rejected due to cytoplasmic changes. The proposed technique allows for the collecting oocytes of good quality that can be used for IMV/IVF techniques and cloning.
One of the challenges of modern crystallography of complex systems (complex metallic alloys, proteins, aperiodic crystals and quasicrystals) is to properly describe the disorder in these systems and discuss correctly the refinement results in terms of the structural disorder. In this paper we briefly discuss a new approach to phasons and phonons in quasicrystals and focus on the new theory of phonons in these materials. A newly derived correction factor for phonons in the form of the Bessel function is the approximated way of describing optic modes in the phonon spectra of quasicrystals. It is applied to a real decagonal quasicrystal in the Al-Cu-Rh system with 56/38 atoms per thick/thin structural unit, based on 2092 unique reflections selected from the collected diffraction data, significantly improving the refinement results. The final R-factor value is 7.24%, which is over 0.5% better result comparing to originally reported. We believe our work will open a broader discussion on the disorder in quasicrystals (and other aperiodic systems) and motivate to develop new approaches to treat the diffraction data influenced by different types of disorder in the new way.
A longstanding folk tradition among rural Russian peasants, ulichnye familii (‘street surnames’) were used by Doukhobors colloquially ‘on the street’ of a village to distinguish among families sharing the same official surname. Similar to Quebecois dit names and Scottish sept names, ulichnye familii arose because of the low surname stock within Doukhobor society. Passed down to succeeding generations and transferred between settlements, these names became a recognized form of address among Doukhobors, helping structure kinship networks and organize social interactions among villagers. When a large contingent of Doukhobors emigrated from the Caucasus to the Canadian prairies in 1899, they continued this naming practice in their settlements well into the early 20th century. A ubiquitous part of their culture for generations, today ulichnye familii have all but disappeared among Doukhobors, as a result of their assimilation, dispersal and modernization. This article offers an analysis of the Doukhobor anthroponymic custom of ulichnye familii: the social factors leading to their adoption; the etymological processes through which these names were formed; the manner in which they were used and transmitted; and the elements contributing to their eventual decline and disuse. It also includes an inventory of extant ulichnye familii among the Doukhobors of the Caucasus and Canada, obtained through extensive fi eld interviews and archival research.