This paper presents the results of obtaining and investigations of Pb1–xBax(Zr1–yTiy)1–zSnzO3 (PBZTS) ceramics with constant x = 0.03 and y = 0.02, and variable z = 0, 0.04, 0.06 and 0.08 (abbreviations of the samples were following PBZTS0, PBZTS4, PBZTS6, PBZTS8, respectively). The investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. The ceramic samples have been obtained by conventional ceramic technology from simple oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The ceramic powders, after calcination, have been pressed into discs and sintered using free sintering (FS) method. For samples obtained in such a way, the dielectric properties at various frequencies and electrical conductivity have been investigated. The increase of Sn content orders the microstructure of ceramics, and as a result the improvement of the dielectric properties of ceramic samples can be obtained.
Blood glucose level monitoring and control is of utmost importance to millions of people who have been diagnosed with diabetes or similar illnesses. One of the conventional tests for measuring how the human body breaks down glucose is IVGTT, the Intravenous Glucose Tolerance Test. The difficulty of computing the models of glucose-insulin interaction presents an issue when attempting to implement them in embedded hardware. The Metabolic P (MP), contrary to other models, does not require solving differential equations to compute, thus it could be an effective modelling approach for real-time applications. The present paper proves that MP system methodology-based IVGTT implementation in the Field Programmable Gate Arrays (FPGA) technology is reasonably precise and sufficiently flexible to be used effectively in multi-user scenarios. Presentation of the state-of-the-art focuses on glucose-insulin interaction models, glucose monitoring systems and MP system implementation techniques. Methods for MP system computations and techniques for their implementation on FPGA, together with the original unified MP system implementation technique, have been presented in this paper. The results of an elaborate investigation into the IVGTT MP systems, as well as their single and unified MP implementation techniques have also been considered. It is shown that the techniques developed are applicable to all known IVGTT MP systems, and can achieve RMSE not higher than 15% using a word length of at least 32 bits. The novel MP system combined quality metrics and its pictorial representation allow the analysis of various implementation characteristics. Compared to the unified pipelined IVGTT MP system implementation technique, the developed unified combinational technique ensures a 2‒3 times higher speed.
In the paper the multiferroic (ferroelectric-ferromagnetic) composites based on ferroelectromagnetic/ferroelectric (BaFe1/2Nb1/2O3 (BFN)) powder and ferrite powder (zinc-nickel ferrite) were obtained by two technological methods. In the composite samples the ratio of the ferroelectromagnetic/ferroelectric powder to the magnetic powder was equal to 90:10. The ceramic powders were synthesized by the classical technological method using powder calcination/solid state synthesis, while densification of the composite powders (sintering) was carried by two different methods: (i) Free Sintering method (FS), and (ii) Spark Plasma Sintering (SPS).
At the work, a comparison of measurement results for composite samples obtained by two sintering methods was made. The studies included the following analysis: DTA, XRD, SEM, DC electrical conductivity, electric permittivity and magnetic properties. The result of measurements presented in the work revealed that the ceramic composite obtained by two different technological sintering method (classical technology – Free Sintering method and Spark Plasma Sintering technique) can be promising lead-free materials for functional applications, for example in sensors for magnetic and electric field.
In this paper an analysis of the surface properties of (Ti,Pd,Eu)Ox thin films prepared by magnetron sputtering has been described. In particular, the results of composition and structure investigations were studied in relation to the surface state and optical properties. It was found that (Ti,Pd,Eu)Ox film was nanocrystalline and had a rutile structure. The average crystallites size was equal to 7.8 nm. Films were homogeneous and had densely packed grains. Investigation of the surface properties by XPS showed that titanium was present at 4+ state (in the TiO2form), palladium occurred as PdO2(also at 4+ state), while europium was in Eu2O3form (at 3+ state). In comparison with the unmodiffied TiO2, the coating with Pd and Eu additives had a rather high transparency (approx. 47%) in the visible light range, its optical absorption edge was shifted towards into the longer wavelengths (from 345 nm to 452 nm), and the width of optical energy gap Egopt was nearly twice lower (1.82 eV). Besides, the resistivity of (Ti,Pd,Eu)Ox at room temperature was 1×103 Wcm. In the case of the film as-deposited on Si substrate (p-type) the generation of photocurrent as a response to light beam excitation (λexc = 527 nm) was observed.
One of the most powerful ways in which we can globalize knowledge, and sociology, is to figure ways in which leading intellectual figures within insufficiently articulated knowledge cultures might inform readings of the other’s work. With the recent revivals of Antonina Kłoskowska and W.E.B. Du Bois in Polish and US sociology respectively, it is a propitious time to figure the ways in which their scholarship aligns, contrasts, and can mutually transform. In particular, the two are both concerned for how marginalized communities with their associated subjectivities engage dominant cultures, but Kłoskowska works within a national/regional frame and Du Bois a global and racial one. Too, Du Bois theorizes from within that marginalized community, with political pointedness, not from outside it or with any attempt to refrain from value judgements. Finally, while Du Bois blends Marxist accounts with a culturally rich account of Blackness and its others, Kłoskowska offers a more semiotic and intersubjective hermeneutic view of how various fusions of horizons might also create a more open world. Those who extend Kłoskowska’s tradition exemplify that very potential while Du Bois, in his very conditions of existence, made racism’s hardest shell manifest. Figuring exemplars of national and racial leadership might, however, invite powerful figurations of the future, but only when their cultural and political constitutions are made explicit.
The aim of the research was to determine the effect of sonochemical treatments on homogenization of powders as well as phase composition and thermal stability of sinters. The compounds were prepared from Eu2O3 and ZrO2 powders, weighed in the mass ratio 1:1. Initially ultrasound treatment was applied. 750-Watt ultrasonic processor VCX-750 equipped with sealed converter VC-334 and horn 630-0219 with the diameter of 13 mm (Sonics & Materials, Inc.) was used as a source of ultrasound. Applied ultrasound frequency was 20 kHz, power density was controlled in the range from 75 W/cm2 to 340 W/cm2. Investigated compounds were synthesized via solid-state reaction (SSR). The Differential Scanning Calorimetry (DSC) was used in order to investigate the effect of sonochemical treatment on the synthesis of prepared mixtures the powders particle size distribution was analyzed. Ultrasound treatment what wasn’t never been reported before.
APNB (alkaline phenolic no bake), widely known as Alphaset is one of the major sand binder systems used in foundries to make molds and cores without application of heat or gas. This is a two part system comprising of a phenol-formaldehyde resin in alkaline medium as binder and range of esters of dibasic acids and/or polyhydric alcohols as hardeners.
Resin performance varies depending upon formulations. Major variables in formulations are mole ratio of phenol: formaldehyde, total alkali content, ratio of two alkalis (NaOH & KOH) and molecular weight of polymers i.e. chain length.
In present work, one mole ratio of phenol & formaldehyde has been chosen to prepare 8 resins with following details.
Table 1.
Physical and chemical properties of eight (fresh) resins, A to H
Properties | A | B | C | D | E | F | G | H |
Viscosity at 30°C (mPs-a) | 56 | 47 | 66 | 51 | 39 | 44 | 49 | 52 |
Na (%) | 5.94 | 3.21 | 5.94 | 3.21 | nil | 2.73 | nil | 2.73 |
K (%) | nil | 3.31 | nil | 3.31 | 7.18 | 3.87 | 7.18 | 3.87 |
Molecular weight | Low | Low | High | High | Low | Low | High | High |
Gel Time at 121°C, mt-sec | 27-0 | 29-30 | 24-0 | 30-0 | 30-0 | 27-30 | 26-30 | 26-0 |
Moisture (%) | 52.43 | 52.42 | 53.01 | 53.75 | 55.58 | 54.12 | 51.61 | 54.03 |
Non-volatile Content (%) | 48.74 | 47.25 | 49.10 | 49.35 | 47.63 | 47.32 | 48.06 | 48.29 |
Specific Gravity | 1.182 | 1.177 | 1.183 | 1.180 | 1.172 | 1.184 | 1.178 | 1.188 |
Free Phenol (%) | 0.47 | 0.42 | 0.44 | 0.43 | 0.37 | 0.27 | 0.41 | 0.20 |
Properties of these 8 formulations have been studied for strength and viscosity over a period of 12 weeks in 4 week interval.
Attempt has been made to develop a simple test for simulating hot & retained strength of molds in laboratory. Process followed for chasing hot and retained strength is described under clause 2.
With more and more understanding of the chemistry of alphaset system in last three & half decades it has been possible to identify role of variables contributing towards specific properties vis a vis developing tailor made formulations to fulfill requirements of individual foundries right from mold making to de coring.
This article deals with the effect of manganese that is the most applied element to eliminate the negative effect of iron in the investigated alloy AlSi7Mg0.3. In this time are several methods that are used for elimination harmful effect of iron. The most used method is elimination by applying the additive elements, so-called iron correctors. The influence of manganese on the morphology of excluded ironbased intermetallic phases was analysed at various iron contents (0.4; 0.8 and 1.2 wt. %). The effect of manganese was assessed in additions of 0.1; 0.2; 0.4 and 0.6 wt. % Mn. The morphology of iron intermetallic phases was assessed using electron microscopy (SEM) and EDX analysis. The increase of iron content in investigated alloys caused the formation of more intermetallic phases and this effect has been more significant with higher concentrations of manganese. The measurements carried out also showed that alloys with the same Mn/Fe ratio can manifest different structures and characteristics of excluded iron-based intermetallic phases, which might, at the same time, be related to different resulting mechanical properties.
The paper presents new ensemble solutions, which can forecast the average level of particulate matters PM10 and PM2.5 with increased accuracy. The proposed network is composed of weak predictors integrated into a final expert system. The members of the ensemble are built based on deep multilayer perceptron and decision tree and use bagging and boosting principle in elaborating common decisions. The numerical experiments have been carried out for prediction of daily average pollution of PM10 and PM2.5 for the next day. The results of experiments have shown, that bagging and boosting ensembles employing these weak predictors improve greatly the quality of results. The mean absolute errors have been reduced by more than 30% in the case of PM10 and 20% in the case of PM2.5 in comparison to individually acting predictors.
We present a prototype of a simple, low-cost setup for a fast scatterometric surface texture measurements. We used a total integrated scatter method (TIS) with a semiconductor laser (λ = 638 nm) and a Si photodiode. Using our setup, we estimated the roughness parameters Rq for two reference surfaces (Al mirrors with flatness λ/10) and seven equal steel plates to compare. The setup is easily adaptable for a fast, preliminary manufacturing quality control. We show is possible to construct a low-cost measurement system with nanometric precision.
This essay is constructed of two parts: the first is a historiographical sketch of several theories concerning nationalism and gender; the second part puts some of these theories into practice in interpreting an article from a fin-desiècle Polish illustrated weekly magazine.
The paper presents research program of bond between glass fiber reinforced polymer bars and concrete in reference to the steel bars. Bond between the reinforcement and concrete is a crucial parameter governing a behaviour of reinforced concrete members and transferring of the internal forces from concrete to the reinforcement. The use of FRP bars as an equivalent reinforcement to steel in concrete structures has increased in recent years. The FRP bars are very different from steel, mainly due to much lower elasticity modulus and their anisotropic structure. Good performance of FRP reinforced concrete requires sufficient interfacial bond between bars and concrete. However, there are no specific standards referring to the surface preparation of these bars, that leads to variable bond behaviour of the composite reinforcement to the concrete. The objective of the study was to investigate the influence of variable parameters on the bond behaviour to concrete. The experimental program consisted of eighteen beam bond specimens varying in: bar diameter (12 mm, 16 mm, 18 mm) and type of reinforcement (GFRP sand – coated and steel bars). Although the GFRP bars indicated good bond behaviour to concrete, the average bond strength was slightly lower than that of steel reinforcement of 16mm and 18 mm, while it was higher for the GFRP bars of 12 mm diameter.
Cockburn Island is one of the most historically significant places on the Antarctic continent. The isle was first surveyed in early 1843 during Captain James Ross famous expedition, but the early explorers failed to recognise its geological and palaeontological significance. Cockburn Island is exceptional for it has the only succession of Upper Cretaceous, Eocene and MiocenePliocene rocks on the continent, which is now known to contain an admirable and diverse fossil record of fauna and flora. These fossil assemblages are providing exciting new information on the evolutionary history of Antarctica. At least 22 species of Late Cretaceous macroinvertebrates and vertebrates have been recognised, whereas the Eocene record is slightly more diverse at 28 macroinvertebrate taxa recorded. The Pliocene macrofossil record is depauperate atsome 11 species, butmicrofossils (diatoms, ostracods, foraminifera) are represented by at least 94 taxa. The palaeoecologic and palaeobiogeographic significance of fossil assemblages is explored in this paper. Further, a checklist of fossils is presented herein, for the first time, as is a bibliography of the geology and palaeontology of the island.
Mud samples from two lakes in West Greenland were kept frozen at 18°C for 18 years. When they were thawed, 4 Cladocera species hatched from diapausing eggs: Daphnia pulex (De Geer, 1778), Macrothrix hirsuticornis (Norman et Brady, 1867) and Chydorus arcticus (Rřen, 1987), which are by far the most abundant Cladocera species in the high Arctic north of 74°N. Another species was Alona quadrangularis (O. F. Müller, 1785), which occurs up to 72°N. All these species gave rise to parthenogenetic offspring and produced ephippia within a time frame comparable to an Arctic summer season. Up to 9 other Cladocera species were likely to be present in the original populations, but did not hatch anymore after 12 years.
In article a two-dimensional photonic crystal (PhC) is considered and modelled as a new generation antireflection coating for optoelectronic devices. Traditional antireflective coatings (ARCs) reduce the reflection of the radiation only – the new generation of antireflective coatings should affect the distribution of the radiation also. Such functionality can be provided by the two-dimensional PhC which reduce the reflection and scatter transmitted light. Prior to the fabrication, the PhCs should be designed and analysed. Results of the analysis should provide quantitative means for choice of materials and design solutions. In work, we analyse the electromagnetic field distribution as Poynting vectors inside the materials of optoelectronic devices, in order to investigate the possibility of improving the construction of future optoelectronic devices. Furthermore, we calculate the reflection and transmission of that ARC. It’s a complex optic analysis of new generation of ARC. The numerical analysis has been performed with the FDTD method in Lumerical Software. In work, we consider the two-dimensional photonic crystal on the top surface of optoelectronic structures. We compared the results with the traditional ARC from these same parameters as PhC: thickness and material. As an example, we presented the application of modelled, photonic crystal, thin-film, GaAs solar cells with PhC on top. The efficiency of this solar cell, using the photonic crystal, was improved by 6.3% over the efficiency of this same solar cell without PhC. Thus, our research strongly suggests that the unique properties of the photonic crystal could be used as a new generation of ARC.
The solar photovoltaic technology is one of the renewable technologies with the potential to shape a future-proof, reliable, scalable and affordable electricity system. It is important to provide better resources for any upcoming technology. CdS/CdTe thin films have long been considered as one enticing option for reliable and cost-effective solar cells to be developed. N-type CdS as a transparent window layer in heterojunction structures is one of the best choices for CdTe cells. In a solar cell structure, window layer material plays a very crucial role to improve its performance. For this reason, this review focuses on the basic and significant aspects such as importance of the window layer thickness, degradation effect, use of nano-wire arrays, and an ammonia-free process to deposit the window layer. Also, an attempt has been made to analyze various processes improving window layer properties. Necessary discussions have been included to review the impact of solar cell parameters on the above aspects. It is anticipated that this review article will fulfill the requirement of knowledge to be used in the fabrication of CdS/CdTe solar cells.
The aim of this work was to present a method of tissue culture research by measuring the impedance of cells cultured in the presence of nichrome. For this purpose, the Electric Cell-substrate Impedance Sensing system was used with a prototype substrate containing comb capacitors made of nichrome. Magnetron sputtering, photolithography and etching processes were used to produce the thin-film electrodes. In the experimental part, cells of mouse fibroblast cell line L929 were cultured according to the instruction manual in complete medium, under controlled growth conditions. Inoculation of arrays was carried out by 300 microliters per well of cell suspension at ~1.2×105 cells/ml. The results of the monitoring cells behavior in tissue culture indicate good cell viability and proliferative potential.