scholarly journals Mechanical and Microstructural Features of Ceramic Hollow Spheres

2019 ◽  
Vol 2 (1) ◽  
pp. 27-31
Author(s):  
Alexandra Kemény ◽  
Dóra Károly
Keyword(s):  
Chemical Composition ◽  
Hollow Spheres ◽  
Type Specimens ◽  
Average Deviation ◽  
Fracture Force ◽  
Geometrical Properties ◽  
Average Value ◽  
Pressure Tests ◽  
Different Types ◽  
Contact Surfaces

Abstract In this study two different types of hollow sphere were examined by mechanical, geometrical and microstructural measurements, and the fracture force, geometrical properties and chemical composition were determined. The diameter of the „01 globocer” type specimens was 2.37 mm on average, while the value for the „03 globocer” type specimens was 6.88 mm, both were smaller than the nominal diameter. The average deviation from the circularity of the 01 globocer specimens was 8 %, the value for the 03 globocer specimens was 6 %, while the average wall porosity was 53±3 % and 56±3 % respectively. The surface of the hollow spheres was uneven, which has an impact on the contact surfaces during pressure tests, which affects the fracture force values. The average value of the fracture force of 01 globocer spheres was 42 N, and of 03 globocer hollow spheres was 288 N. The diameter had a bigger impact on the fracture force values of the type 01 specimens than in the case of 03.

The Chemical Decontamination Process Intensification, using Ultrasounds

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Eugenia Pantru ◽  
Gheorghit Jinescu ◽  
Rozalia R�dulescu ◽  
Antoneta Filcenco Olteanu ◽  
Cosmin Jinescu
Keyword(s):  
Chemical Composition ◽  
Process Intensification ◽  
Sulphuric Acid Solution ◽  
Liquid Ratio ◽  
Polluted Soils ◽  
Chemical Decontamination ◽  
First Case ◽  
Ultrasound Field ◽  
Different Types ◽  
Main Factors

This paper presents an intensive procedure used for the decontamination of the soils, which were radioactively contaminated by uranium, due to the occurrence of some antropic accidents, in order to limit the area�s pollution. The procedure used for the chemical decontamination of the polluted soils was the washing one and the decontamination degree is comparatively presented depending on the ultrasounds� presence and absence. The lab testes were performed on five types of soils , which were characterized from the granulometric, structural and chemical composition viewpoint, all these aspects represent the main factors, which determine the applied decontamination procedure�s limits and performances correlated with its utilization costs. The decontamination procedure�s kinetics for each type of soils was analyzed, using successively three different types of reagents (water, 0.1 M sulphuric acid solution and chloro-sodic solution � 100 g/L sodium chloride + 10 g/L sodium carbonate in water) for a solid to liquid ratio of 1:2, during 2 h, at a temperature of 20oC in a mechanic stirring system respectively in ultrasounds field. It was observed that the decontamination degree increases with up to 15-20% in case of the ultrasound field utilization comparing to the first case.

scholarly journals Relationship between the Optical Properties and Chemical Composition of Urban Aerosol Particles in Lithuania

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Julija Pauraite ◽  
Kristina Plauškaitė ◽  
Vadimas Dudoitis ◽  
Vidmantas Ulevicius
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Organic Aerosol ◽  
Single Scattering ◽  
Chemical Compositions ◽  
Spectra Analysis ◽  
Average Value ◽  
Aerosol Mass ◽  
In Situ Investigation

In situ investigation results of aerosol optical properties (absorption and scattering) and chemical composition at an urban background site in Lithuania (Vilnius) are presented. Investigation was performed in May-June 2017 using an aerosol chemical speciation monitor (ACSM), a 7-wavelength Aethalometer and a 3-wavelength integrating Nephelometer. A positive matrix factorisation (PMF) was used for the organic aerosol mass spectra analysis to characterise the sources of ambient organic aerosol (OA). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass-burning OA (BBOA), more and less oxygenated OA (LVOOA and SVOOA, respectively), and local hydrocarbon-like OA (LOA). The average absorption (at 470 nm) and scattering (at 450 nm) coefficients during the entire measurement campaign were 16.59 Mm−1 (standard deviation (SD) = 17.23 Mm−1) and 29.83 Mm−1 (SD = 20.45 Mm−1), respectively. Furthermore, the absorption and scattering Angström exponents (AAE and SAE, respectively) and single-scattering albedo (SSA) were calculated. The average AAE value at 470/660 nm was 0.97 (SD = 0.16) indicating traffic-related black carbon (BCtr) dominance. The average value of SAE (at 450/700 nm) was 1.93 (SD = 0.32) and could be determined by the submicron particle (PM1) dominance versus the supermicron ones (PM > 1 µm). The average value of SSA was 0.62 (SD = 0.13). Several aerosol types showed specific segregation in the SAE versus SSA plot, which underlines different optical properties due to various chemical compositions.

scholarly journals Low Frequency Noise Remove from EEG Signal

2020 ◽  
Vol 9 (1) ◽  
pp. 1510-1513
Keyword(s):  
Human Brain ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Eeg Signal ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Average Value ◽  
Different Types ◽  
The Brain

The electrical activity of the brain recorded by EEG which used to detect different types of diseases and disorders of the human brain. There is contained a large amount of random noise present during EEG recording, such as artifacts and baseline changes. These noises affect the low -frequency range of the EEG signal. These artifacts hiding some valuable information during analyzing of the EEG signal. In this paper we used the FIR filter for removing low -frequency noise(<1Hz) from the EEG signal. The performance is measured by calculating the SNR and the RMSE. We obtained RMSE average value from the test is 0.08 and the SNR value at frequency(<1Hz) is 0.0190.

scholarly journals Variations of carbon monoxide in the atmosphere of Antarctica according to ground-based and satellite measurements

2019 ◽  
pp. 97-106 ◽  
Author(s):  
V. P. Ustinov ◽  
E. L. Baranova ◽  
K. N. Visheratin ◽  
M. I. Grachev ◽  
A. V. Kalsin
Keyword(s):  
Satellite Data ◽  
Total Content ◽  
Mixing Ratio ◽  
Satellite Measurements ◽  
Average Volume ◽  
Average Deviation ◽  
Average Value ◽  
Surface Measurements ◽  
Good Agreement ◽  
Measurement Period

The results of systematic (2003–2017) measurements of the total content and the volume mixing ratio of CO at Novolazarevskaya station with a spectrometer with a resolution of 0.2 cm– 1 are presented. The inverse problem of determining the total CO content, as well as interfering gases (H2O and N2O), was solved using the SFIT4 software package. Data analysis showed that over the measurement period the average total CO content at Novolazarevskaya amounted to (8 ± 2) 1017 molec/cm2, and the average volume mixing ratio amounted to (37 ± 8) ppb. The obtained data are compared with variations in the total content of CO in Arrival-Heights station, with MOPITT satellite data, as well as with surface values of CO concentration at Syova station. The maximum values of CO are observed in September, the minimum — in January–February. For all the considered series, the trends are insignificant, while there are periods of increased CO content (2010). In recent years (2014–2017) there is a tendency towards an increase in the minimum values of CO. For  Novolazarevskaya and  Arrival-Heights satellite data are characterized by the excess of over ground data, amounting to 19% and 14%, respectively, while there is a seasonal dependence of the deviation with the minimum in December–January. Surface measurements of the total CO content are in fairly good agreement at Novolazarevskaya and Arrival-Heights, and since 2010 the average deviation is 2.4%. The average value of the concentration of CO on Syova 51 ppb is higher than the average volume mixing ratio at Novolazarevskaya. According to the spectral, wavelet and composite analyzes, in all the considered series there are oscillations in the range of 6–45 months with closely coinciding periods and phases.

scholarly journals Influence Assessment of the Information Concerning the Bearing Type of Axle Box of Cars on the Automatic Classification Accuracy of Heated Boxes

2021 ◽  
pp. 5-14
Author(s):  
V. V Burchenkov
Keyword(s):  
Density Distribution ◽  
Probability Density ◽  
Heating Temperature ◽  
Threshold Value ◽  
Probability Density Distribution ◽  
Practical Implementation ◽  
System Of Equations ◽  
Average Value ◽  
Optimal Thresholds ◽  
Different Types

Purpose. The main purpose of the work is to determine and classify the heated cars’ boxes based on the probability of appearance of roller and cassette type boxes in the classes of heated and overheated boxes, as well as the laws of probability density distribution of the recognition signs of normally heated and overheated roller and cassette type boxes. Methodology. The operation features of freight cars with cassette type axle boxes with increased operating heating have been investigated. The methodology of assessing the probability of recognition errors was proposed, which takes into account the fact that sets of normally heated and overheated boxes consist of subsets of boxes with different types of bearings. A system of equations is obtained, the roots of which represent еру values that minimize the recognition probability of the errors of the heated boxes. Findings. It was found out that with some methods of determining the bearing type, for example, by the average value of the ranges of thermal image for each car, the probability of erroneous selection may depend on the probability density distribution of the sign for bearings of different types and the threshold value of this sign. The optimal thresholds for detecting the overheated roller boxes in comparison with the optimal thresholds for detecting overheated cassette boxes were determined. It has been established that the pass of an overheated cassette bearing, provided that the type of bearing is determined correctly, is less likely to lead to an accident than if the cassette box is classified as a roller box. The rejection criteria of axle boxes according to their heating temperature difference on one of the wheel set axis for three variants of settings of the alarm system according to an arrangement of multipurpose complexes of technical means (CTM) were formulated. The practical implementation of this method of adjusting the CTM settings for the Minsk branch of the Belarusian Railways was demonstrated. Originality. A system of equations is obtained, which allows finding the optimal values of temperature thresholds for the detection of overheated roller and cassette boxes under the assumption that the error probabilities in the selection of boxes by their types are known and constant. Practical value. The developed method of adjusting the alarm settings of CTM makes it possible to significantly reduce unjustified train delays and the number of car uncouplings.

scholarly journals The laboratory tests of hybrid layers combining hardfacing and nitriding dedicated to increase the durability of forging tools in hot forging processes

2019 ◽  
Vol 91 (2) ◽  
Author(s):  
Paweł Widomski ◽  
Zbigniew Gronostajski ◽  
Marcin Kaszuba ◽  
Jagoda Kowalska ◽  
Mariusz Pawełczyk
Keyword(s):  
Surface Layer ◽  
Chemical Composition ◽  
Laboratory Tests ◽  
Hot Forging ◽  
Composition Analysis ◽  
Wear Resistant ◽  
Gas Nitriding ◽  
Use Wear ◽  
Different Types ◽  
Hybrid Layers

In response to the growing need to use wear-resistant layers that increase durability of tools in forging pro-cesses, hybrid layers have been proposed that combine hardfacing with nitriding treatment. This article presents the results of laboratory tests of surface wear-resistant layers made with a new hybrid technology Gas-Shielded Metal Arc surfacing (hardfacing) with ZeroFlow gas nitriding. Specimens made with hardfacing or nitriding were prepared and examined. Analysis covered the thorough microstructure study, EDX chemical composition analysis and microhardness analysis. In experiment, 3 different types of nitrided layers were proposed for alpha, gamma prim and epsilon nitrides in the surface layer. The results of metallographic research in the surface layer was presented. The analysis of chemical composition in the particular overlay welds was performed to determine the content of alloying elements in the particular overlay welds. The susceptibility to nitriding of used weld materials as well as the ability to form particular types of nitrides on selected welded substrates was also tested.

scholarly journals The Role of the Diameter of the Titanium, Fiber and Zirconium Posts

2018 ◽  
Vol 11 ◽  
pp. 2241-2249
Author(s):  
Vesna Jurukovska Shotarovska ◽  
Biljana Kapusevska ◽  
Nikola Dereban
Keyword(s):  
Mechanical Properties ◽  
Fracture Strength ◽  
Software System ◽  
Fracture Force ◽  
Fiber Posts ◽  
Special Software ◽  
Different Types ◽  
Different Diameters

The goal is to compare the strength of a fracture among titanium, fiber and zirconium posts. We have formed three group: titanium, fiber and zirconium,, and each group has 20 samples with 3 different diameters. The posts were tested using "Shimadzu Univerzal Testing Mashine" at the same distance, and the force was applied to all at the same place. The fracture strength was registered on a special software system. Between posts with the same diameter (1.2 mm) the greatest average fracture force has titanium posts 161.69 N (± 0.07), followed by fiber posts 45.38N (± 0, 01) and zirconium posts 34.81N (± 0.01). between the subgroups of the same  diameter (1.35mm), the greatest average fracture strength has the titanium posts 165.26N (± 0.01), followed by the fiber posts 71.57N (± 0.01) and zirconium posts 46.53N (± 0.004). between the subgroups of the same diameter (1.5 mm) the largest average fracture force has titanium posts 202.42N (± 0.01), followed by fiber posts 73.67N (± 0.004) and zirconium posts 67.15N (± 0.004). The diameter of the different types of posts gives different mechanical properties that affect differently the resistance of the fracture strength.

scholarly journals The sensory acceptability of a tilapia (Oreochromis niloticus) mechanically separated meat-based spread

2012 ◽  
Vol 15 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Daniela De Grandi Castro Freitas ◽  
Alda Letícia da Silva Santos Resende ◽  
Angela Aparecida Lemos Furtado ◽  
Luana Tashima ◽  
Henrique Muniz Bechara
Keyword(s):  
Chemical Composition ◽  
Oreochromis Niloticus ◽  
Raw Material ◽  
Common Salt ◽  
Microbiological Analysis ◽  
Sensory Acceptability ◽  
Different Types ◽  
Adequate Quality ◽  
Mechanically Separated Meat ◽  
Hedonic Scale

Mechanically Separated Meat (MSM) is an alternative for the diversification of new fish-based products and also as a solution for the use of waste from the filleting industries. Tilapia MSM was used in this study for the formulation of a fish spread aimed at investigating its acceptability by consumers. Two spread formulations were prepared with different types of commercial salt: seasoned salt (A) and common salt (B). The consumers (112) evaluated their acceptance with respect to overall impression, spreadability, appearance and flavour acceptability on a 9-point hedonic scale. A microbiological analysis of the Tilapia MSM was also carried out and the chemical composition of the Tilapia MSM-based spread determined. When considering the acceptance of all the consumers, the overall impression, appearance and flavour were significantly (P < 0.05) lower for the spread made with common salt (B). However, three different consumer segments could be found from the overall impression of the Tilapia MSM-based spread. The largest segment also preferred the spread made with the seasoned salt (A), but both products were well accepted. The tilapia MSM presented adequate quality as a raw material according to the technical regulations for microbiological standards. The final product presented the following chemical composition: moisture - 62.17%; ash - 2.11%; protein - 9.75% and lipid - 18.81%. These results could be of great importance for the industry in developing and marketing new products obtained from mechanically separated Tilapia meat.

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