1,780 research outputs found
Psychodynamics and Regression of Social Groups
The paper discusses same aspects of psychodynamics and regression of social groups.
The aims of the study are: 1. to promote the understanding of group processes which
point out the presence of complex phenomena within social group and should help group
members and a group leader to function on the higher level of sensitivity, capability and
effectiveness; 2. to stimulate the knowledge implementation in problem resolving among
social groups (organizations). The group psychodynamic, group regression and mechanisms
against it, are theoretically based on aspects of psychoanalytic group psychology,
using the method of descriptive literature overlook. Conclusion: the permanent evaluation
of group functioning, group situation and group processes by some group members
and by the whole group are conditions for preservation of regressive group phenomena
on rather low level, or successful functioning on more mature level, creating the feeling
of satisfaction in group and among its members
Long-term monitoring of the broad-line region properties in a selected sample of AGN
We present the results of the long-term optical monitoring campaign of active
galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of
the Russian Academy of Science. This campaign has produced a remarkable set of
optical spectra, since we have monitored for several decades different types of
broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and
radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of
the properties of the broad line region (BLR) of these objects is based on the
variability of the broad emission lines. We hereby give a comparative review of
the variability properties of the broad emission lines and the BLR of seven
different type 1 AGNs, emphasizing some important results, such as the
variability rate, the BLR geometry, and the presence of the intrinsic Baldwin
effect. We are discussing the difference and similarity in the continuum and
emission line variability, focusing on what is the impact of our results to the
supermassive black hole mass determination from the BLR properties.Comment: Published in Frontiers in Astronomy and Space Scienc
Microstructural evolution during friction stir welding of AlSi1MgMn alloy
This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6) obtained through the Friction Stir Welding (FSW) process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out
Mikrostrukturni razvitak AlSi1MgMn slitine tijekom zavarivanja trenjem
This paper provides the research of the influence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6) obtained through the Friction Stir Welding (FSW) process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.U radu se istražuje uticaj geometrijskih i kinematskih parametara na mikrostrukturu i mehanička svojstva zavarenog spoja od aluminijske slitine AlSi-1MgMn (6082-T6) dobivene postupkom zavarivanja trenjem (ZT). Parametri provedenih pokusa su brzina zavarivanja, kutna brzina okretanja alata, kut nagiba trna, promjer trna i promjer čela alata. Kod dobivenih zavarenih uzoraka izvedena su dinamička ispitivanja na udarnu žilavosti i određene su mikrostrukturne zone
The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran
The application of the hydrogen-palladium electrode (H2/Pd) as the indicator electrode for the determination of relative acidity scale (Es, mV) of tetrahydrofuran (THF) and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH), which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol) and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid) were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051
Comparison of 35 and 50 {\mu}m thin HPK UFSD after neutron irradiation up to 6*10^15 neq/cm^2
We report results from the testing of 35 {\mu}m thick Ultra-Fast Silicon
Detectors (UFSD produced by Hamamatsu Photonics (HPK), Japan and the comparison
of these new results to data reported before on 50 {\mu}m thick UFSD produced
by HPK. The 35 {\mu}m thick sensors were irradiated with neutrons to fluences
of 0, 1*10^14, 1*10^15, 3*10^15, 6*10^15 neq/cm^2. The sensors were tested
pre-irradiation and post-irradiation with minimum ionizing particles (MIPs)
from a 90Sr \b{eta}-source. The leakage current, capacitance, internal gain and
the timing resolution were measured as a function of bias voltage at -20C and
-27C. The timing resolution was extracted from the time difference with a
second calibrated UFSD in coincidence, using the constant fraction method for
both. Within the fluence range measured, the advantage of the 35 {\mu}m thick
UFSD in timing accuracy, bias voltage and power can be established.Comment: 9 pages, 9 figures, HSTD11 Okinawa. arXiv admin note: text overlap
with arXiv:1707.0496
Natural radionuclides in soil profiles surrounding the largest coal-fired power plant in Serbia
This study evaluates the influence of the largest Serbian coal-fired power plant on radionuclide concentrations in soil profiles up to 50 cm in depth. Thirty soil profiles were sampled from the plant surroundings (up to 10 km distance) and analyzed using standard methods for soil physicochemical properties and gamma ray spectrometry for specific activities of natural radionuclides (K-40, Ra-226 and Th-232) Spatial and vertical distribution of radionuclides was determined and analyzed to show the relations between the specific activities in the soil and soil properties and the most influential factors of natural radionuclide variability were identified. The radiological indices for surface soil were calculated and radiological risk assessment was performed. The measured specific activities were similar to values of BACKGROUND: levels for Serbia. The sampling depth did not show any significant influence on specific activities of natural radionuclides. The strongest predictor of specific activities of the investigated radionuclides was soil granulometry. All parameters of radiological risk assessment were below the recommended values and adopted limits. It appears that the coal-fired power plant does not have a significant impact on the spatial and vertical distribution of natural radionuclides in the area of interest, but technologically enhanced natural radioactivity as a consequence of the plant operations was identified within the first 1.5 km from the power plant
"It happened, what's the problem?" and "A guide through the problem" - A model for consideration of ecological issues in chemistry education
In order to improve the ability to apply knowledge of chemistry (acquired in the existing educational system) in real life, the model for consideration of ecological issues was developed and applied in high school. The model consists of a continuous text "It Happened, What's the Problem?" and a test with non-continuous text "A Guide Through the Problem", which were prepared for consideration of the problem of eutrophication. All results obtained (average achievement of 70.9 +/- 14.3 %) showed that the application of the model enabled: understanding of an ecological problem based on scientific representations of the term eutrophication given in the continuous text, realization that pollution of the environment may be directly related to modern life, application of acquired knowledge of chemistry to observe and understand the cause and effect of eutrophication in the environment, to draw a scientific conclusion, and understanding the importance of science and technology discoveries for solving ecological problems. In addition, the model contributed to the development of student's environmental literacy (ecological knowledge and cognitive skills), ability to think critically, and provided possibilities for classroom knowledge to become applicable in real life
Efects of chemical and physical soil properties on activity phosphomonoesterase
In the present work, effects of hemical and phisical soil properties on activity phosphomonoesterase are presented. Chemical and physical properties of calcomelanosols, chernozems, humogleys, solonetzes and fluvisols have been determined by standard methods. The highest total activities of PME were found in brownized calcareous black soil and lowest in Bt,na in the solonetz horizon. PME activity is correlated to humus content. pH is negatively and significantly correlated with the activity of acid PME. The activity of PME has not been significantly influenced by inorganic P and K contents in the investigated soils. Activites of alkaline and acid PME are not in significant correlations with the contents of the investigated soil fractions.Publishe
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