The Administrative Costs of Local Government Property-Based User Charges and Their Regressivity

The paper measures the administrative costs (assessment and collection costs) of immovable property user charges in local governments in Croatia. This study represents a small scale survey comprising mostly small local governments. First, we establish their costs structure and then we compare the cost-revenue ratio with their size. As expected, the administrative costs of the analyzed user charges turned out to be regressive in regards to the size of local governments. The results imply that substitution of those different charges would be beneficial for local government budgets. In order to mitigate the problem we propose several alternatives: one general tax/charge; amalgamation of the smallest local governments or referring to assessment and collection of user charges in small local governments to the larger/mutual unit

ODS+Hf and AISI 316L steel surface variations at high laser intensity, 1013 W/cm2, in air and vacuum: comparative study

The behavior of Oxide Dispersion Strengthened (ODS) steel with addition of hafnium, as well as AISI 316L steel, at high laser intensity of ~1013 W/cm2 in ambiences of air and vacuum, was studied. Irradiation source was Ti:Sapphire laser operating at 804 nm and pulse length of ~65 fs. Morphological and chemical studies were considered, thus that: (i) given laser intensity induced damages on both steels with the damage being more prominent on AISI 316L steel; (ii) various surface features were present, such as coral-like structure and Laser Induced Periodic Surface Structures (LIPSS), with LIPSS being dominant on the surface; (iii) the interaction was accompanied by generation of plasma above the target, and (iv) chemical analysis has shown that surface elemental content also depends on the ambience used.SPIG 2022 : 31st Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers and abstracts of invited lectures, topical invited lectures and progress reports; September 5-9,2022, Belgrad

The Influence of Pregnancy on Development and Course of Chronic Relapsing Experimental Autoimmune Encephalomyelitis in Rats: Implications for Multiple Sclerosis

Multiple sclerosis is a chronic, autoimmune disease of the central nervous system, which mainly affects young women during a reproductive period of life. Since, its symptoms might be significantly affected by pregnancy, in this study we investigated the development and kinetics of disease in the model of chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE), induced in genetically susceptible Dark Agouti (DA) strain of rats. They were sensitized with bovine brain white matter homogenate (BBH) in complete Freund’s adjuvant during the first, second or third week of pregnancy, and the disease scores were compared between treatment groups, and identically treated nongravid females. Additionally, the susceptibility to the induction of EAE was tested in offspring of mothers that during the pregnancy were sensitized with BBH. The data have shown that pregnancy does not block the induction of EAE, but that it significantly changes the course of diseases, depending on time of immunization. In rats sensitized during the first week of gestation the onset of the clinical signs was delayed, but after the delivery the intensity of disease significantly increased. Similar aggravation, with appearance of monophasic form of disease was observed in the group of rats sensitized during the third week of gestation. On the contrary, in rats sensitized during the second week of gestation the beneficial effects were observed, with later onset of attacks, and lower disease score. Furthermore, offspring of these rats after immunization with BBH developed a monophasic form of EAE of lower intensity, suggesting that some protective factors might be transferred across the placenta

Synthesis and characterization of Cu-ZrB2 alloy produced by PM techniques

The copper alloy with 7vol.% ZrB2 examined in this study was consolidated via powder metallurgy processing (PM) by combining mechanical alloying and hot pressing process. Structural changes, morphological properties and elemental analysis of the hotpressed samples were studied as a function of milling time with the use of X-ray diffraction, scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometry (EDS). Also, mechanical properties of the Cu-7vol.%ZrB2 alloy was investigated. Distribution of ZrB2 particles and presence of agglomerates in the Cu matrix directly depend on the milling time and show strong influence on hardness, compressive and electrical properties of Cu-ZrB2 alloys. [Projekat Ministarstva nauke Republike Srbije, br. 172005

The Effect of Ball-Powder Ratio on The Mechanical and Structural Properties of CuZrB Composite Materials Fabricated by Powder Metallurgy

Copper matrix composites exhibit excellent mechanical and thermal properties. The composite consists of copper (Cu), zirconium (Zr), and boron (B) and is produced using the powder metallurgy technique. The high-energy ball milling was applied for mechanical alloying of the Cu-Zr-B powder mixture to achieve the desired ratio for obtaining a copper matrix reinforced with ZrB2 ceramic particles. The milling times of 10 and 40 hours for two different ball-to-powder ratios are investigated for a powder mixture with a composition of Cu-2.71Zr-2.27B (wt.%). XRD and SEM analyses were employed to determine structural and morphological changes in the mechanically alloyed powder mixture. Investigation of the morphological parameters shows that with prolonged milling, the shape of mixed particles becomes more uniform, while their structural parameters have been drastically changed. It is determined that during high-energy ball milling of the Cu-2.71Zr-2.27B (wt.%), the size of the copper powder decreases as the mechanical alloying increases for both ball-powder ratios. Dislocation densities reach their maximum value at around 30 hours of mechanical alloying for both ball-powder ratios, with dislocation density being higher for the 1:15 ratio, after which they decrease owing to the recrystallization of the copper matrix. XRD analysis shows no presence of ZrB2 reinforcement particles or oxides during milling

Polymer characteristics and mechanical properties of bulk-fill, giomer, fiber-reinforced and low-shrinkage composites

Introduction/Objective. The objective was to determine the degree of conversion (DC), cross-link density, percentage of leachable monomers, flexural strength (FS), and hardness (HV) of nanohybrid, nanofilled bulk-fill, giomer, fiber-reinforced, and low-shrinkage composites. Methods. Standardized specimens (n = 5/group) of Tetric EvoCeram Bulk Fill, Filtek Bulk Fill, Beautifil, EverX posterior, Kalore, Filtek Z250 (microhybrid control), and Tetric EvoCeram (nanohybrid control) were subjected to micro-Raman spectroscopy, three-point bending, and HV. Cross-linking density and leachable monomers were ascertained based on the ratio of HV and DC before and after immersion in absolute ethanol. Results. DC was in the range 50.4–70.5%, the highest for Filtek Bulk and the lowest for Kalore. The highest %DC change was in Beautifil (10.3%) and the lowest in Filtek Bulk (1.4%) and Z250 (1.28%). FS ranged between 78.9 MPa (TEC) and 126.7 MPa (Filtek Bulk). HV ranged between 58.6 (Kalore) and 113.9 (Z250) and significantly decreased post-immersion (19–55%). HV48h inversely correlated to HV% loss (r = -0.761), whilst DC positively correlated with FS (r = 0.893). Conclusion. Filtek Bulk, EverX, and Z250 showed the highest DC. The lowest DC and mechanical properties were observed for Kalore. The greatest cross-link density was shown by Filtek Bulk. There were up to 10% of leachable monomers. DC and FS positively correlated

Perforin Expression in Peripheral Blood Lymphatic Cells of Patients Subjected to Laparoscopic or Open Cholecystectomy

Perforin-(P-) related characteristics of cytotoxic T lymphocytes and natural killer cells were investigated in peripheral blood of patients subjected to open (OC; n = 23) or laparoscopic cholecystectomy (LC; n = 21) and healthy controls (n = 20). Blood samples were obtained preoperatively and 24 hours after the surgeries, and the data were correlated with the intensity of cholestasis and concomitant inflammation, determined by functional hepatic tests. Postoperative differences were found to be minimal: OC decreased only the percentage of CD56+ cells, while LC decreased the fraction of CD8+P+ cells and augmented the mean fluorescence intensity of P in CD56 cells. Patients elected for OC had, however, higher preoperative numbers of total P+, CD3+P+, and CD4+P+ cells than patients elected for LC and healthy controls, while both groups of patients, preoperatively, had lower fraction of CD16+P+ and CD56+P+ cells. These changes were in high correlation with blood concentrations of CRP, AP, and ALT, emphasizing the link between the preoperative cholestasis and inflammation and P-dependent cytotoxic mechanisms

Action of pulsed lasers on titanium target: surface effects

The interaction of lasers with metals has been studied for decades, and has been especially intensified lately, due to the development of new, efficient pulsed lasers. Titanium has a number of excellent properties, making it applicable in various modern technologies. Treatment and processing of titanium is possible with various techniques, and the application of lasers gives a special quality, such as high precision machining or obtaining specific structures on the surface which cannot be generated by other methods. During our research, surface processing of titanium was conducted by various pulsed lasers: nanosecond CO2 laser, picosecond Nd:YAG laser and femtosecond Ti: sapphire laser. In order to find the optimal conditions for surface modification of titanium, the influence of different laser parameters (wavelength, pulse duration, pulse energy, etc.), as well as the influence of the ambient, was examined. The titanium samples were irradiated in different environments, ie. in air, oxygen, nitrogen, carbon dioxide, helium and in vacuum, which affected the chemical composition and morphology of the target surface.SPIG 2022 : 31st Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers and abstracts of invited lectures, topical invited lectures and progress reports; September 5-9,2022, Belgrad

ns-Laser – titanium interaction: hydrogen ambience

Interaction of a pulsed, ns-laser operating at 10.6 μm with a titanium target in hydrogen ambience was studied. In general, interaction in this type of environment is scarcely studied; however it can be of great importance. Titanium and its alloys show excellent physical and chemical properties and for these reasons they are attractive for aero-space and marine engineering, medicine, nuclear problematics, etc. Some phenomena, especially the action of thermal flux on a material, within fission/fusion reactor for example, can be simulated by ns-laser [1,2]. The Ti-surface variations at high TEA CO2 laser energy density/fluence of ~20 J/cm2 and intensity of ~60 MW/cm2 were investigated in this work. Irradiation was carried out at a reduced H2 atmosphere of ~200 mbar [3]. The energy absorbed from the laser beam is partially converted to thermal energy, which generates a series of effects, such as melting, vaporization of the molten material, shock waves, etc. Also, it should be mentioned that irradiation was accompanied by generation of plasma in front of the target. The following titanium target surface changes and phenomena were observed: (i) the damages were only on a superficial level (Fig. 1B) with depth ≤ 2 μm; (ii) appearance of pores on the grain boundaries in the central irradiated zone (Fig. 1A). The cracking effect is visible as well in this zone. In the main, all changes can be attributed to the extra-fast heating and cooling process; (iii) in the peripheral zones similar features were registered, while the transition between irradiated and non-irradiated region is sharp. It can be concluded from this study that the reported laser fluence and intensity, in hydrogen ambience, effectively modified the titanium target. The created surface structures generally could be acceptable in cases where high roughness is required, while for some applications in nuclear technologies additional studies should be done (in this context, the presence of H2 in fusion reactor materials is not desirable [3]).IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad