Microstructural changes arisen by interaction of picosecond laser with austenitic materials

Investigation was carried out on austenitic material samples – stainless steel and iron base superalloy that are widely used at elevated temperatures and pressures. The samples were exposed to Nd:YAG pulsed laser, with wavelength of 1064 nm and pulse duration of 170 ps. Different pulse energy and number of pulses were applied. Spots obtained by laser interaction were observed by optical and scanning electron microscope and analyzed by energo-dispersive spectroscopy. Vickers microhardness tests were performed. In this paper, the microstructural changes, arisen by different pulse energy and number of pulses, were discussed with the aim to determine optimal laser parameters in surface treatment process

Divlje deteline na zaslanjenim staništima Vojvodine

On soil habitats used as pastures and hayfields the presence of wild trefoils is significant. Wild trefoils are important fodder crops and they increase the nutritive value of the plant biomass. 10 out of the 22 species of the genus Trifolium, which are found on the soil habitats in Vojvodina, are shown and they characterize the given ecosystems. Their general distribution is shown as well as their floristical element, distribution in Europe, ecological indices, life form, the major morphological characteristics and their distribution on the soil habitats in Vojvodina.Na slatinskim staništima, koja se koriste kao pašnjaci i senokosi, značajno je prisustvo divljih detelina, koje su važne krmne biljke i povećavaju hranljivu vrednost biljne biomase. Od 22 vrste roda Trifolium, koje su konstatovane na slatinama Vojvodine, prikazane su 10 koje karakterišu date ekosisteme. Dato je njihovo opšte rasprostranjenje, florni element rasprostranjenje u Evropi, ekološki indeksi, životna forma, najvažnije morfološke karakteristike i njihovo rasprostranjenje na slatinama u Vojvodini

Pipiza quadrimaculata Panzer

<i>Pipiza quadrimaculata</i> (Panzer) <p>(Figs. 3, 17, 18, 25, 26)</p> <p> <b>Material studied</b> (104ɗ 136Ψ): <b>Slovenia</b>: Julian Alps (Savica, 22.05.1988, ɗ, leg. Radnović, 14.06.1988, ɗ 5Ψ, leg. Vujić); Kamniške and Savinjske Alps (Kamniška bistrica, 16.06.1988, ɗ, leg. Vujić; Savinja, 16.06.1988, ɗ 2Ψ, leg. Radnović, Vujić; Matkov kot, 0 1.07.1989, ɗ, leg. Vujić; Matkov kot - Logarska dolina, 25.05.1989, ɗ, leg. Vujić; Logarska dolina, 25.05.1989, ɗ, leg. Vujić); mountain Menina, 24.05.1989, ɗ, leg. Vujić; mountain Menina - Kamnik, 24.05.1989, ɗ Ψ, leg. Vujić. <b>Croatia</b>: mountain Gorski Kotar, 27.05.1990, 3ɗ, leg. Vujić. <b>Bosnia and Herzegovina</b>: Kladanj, 13.05.1989, ɗ, leg. Vujić; mountain Konjuh, 25.06.1989, 3ɗ Ψ, leg. Vujić, 30.07.1989, Ψ, leg. Vujić; mountain Jahorina, 26.06.1989, 2ɗ 2Ψ, leg. Vujić, 14.06.1991, ɗ Ψ, leg. Vujić; mountain Bjelasica, 26.06.1989. Ψ, leg. Vujić. <b>Montenegro</b>: mountain Durmitor (17.07.1981, Ψ, leg. Šimić; Ž abljak, 0 2.07.1983, Ψ, leg. Šimić; Mlinski potok, 22.06.1985, 7ɗ 7Ψ, leg. Vujić, 28.06.1989, ɗ, leg. Vujić, 20.07.1997, 3Ψ, leg. Radenković, 3Ψ leg. Vujić; 23.06.1998, ɗ Ψ leg. Milenković; Sušičko jezero, 25.06.1985, Ψ, leg. Vujić; Sušičko jezero-Zlatica, 19.05.2000, ɗ leg. Vujić; Otoka Crnog jezera, 0 2.07.1981, Ψ, leg. Aleksić, 02- 04.07.1981, Ψ, leg. Ercegovac, 20.06.1983, 2ɗ, leg. Aleksić, Vujić, 24.06.1983, 2ɗ 8Ψ, leg. Aleksić, Vujić, 26.06.1983, 2Ψ, leg. Aleksić, Vujić, 0 3.07.1994. ɗ leg. Radenković; 14.07.1997, 4 Ψ leg. Mićić, 5Ψ leg. Radenković; Crno jezero, 21.06.1983, Ψ, leg. Šimić; Č eline, 27.06.1983, ɗ 2Ψ, leg. Aleksić, Vujić; Mlinski potok - Ivan do, 0 2.08.1998, ɗ leg. Vujić; Ivan do, 27.06.1993, Ψ leg. Vujić; Savin kuk, 25.06.1983, 3Ψ, leg. Aleksić, Vujić; Donja Ališnica, 0 6.07.1991, Ψ, leg. Radnović; Jablan jezero, 0 7.07.1991, Ψ, leg. Vujić; Jablan jezero, 0 6.07.1992, Ψ, leg. Vujić). <b>Serbia</b>: mountain Kopaonik (<i>Picea abies</i> forest, ɗ leg. Milenković; 20.07.1985, ɗ 2Ψ, leg. Šimić; 17- 20.07.1985, ɗ, leg. Šimić; 17.07.1985, ɗ, leg. Šimić; Samokovska reka, 19.07.1985, Ψ, leg. Vujić, 19.06.1996, ɗ 3Ψ leg. Milankov; 14.08.1997, Ψ leg. Vujić, 14.08.1997, 2Ψ leg. Milidragović; 14.08.1997, Ψ leg. Milidragović; 16.06.1986, ɗ Ψ, leg. Bożičić, Šimić, 0 5.07.1986, ɗ16Ψ, leg. Radišić, Radnović, Vujić, 21.06.1991, 2ɗ Ψ, leg. Šimić, Vujić; 16.06.1986, 21ɗ 2Ψ, leg. Bożičić, Šimić, Vujić, 0 3.08.1987, Ψ, leg. Vujić, 22.06.1991, 2ɗ Ψ, leg. Šimić, Vujić; 22.06.1991, Ψ, leg. Vujić; 24.05.1992, 2Ψ, leg. Vujić; Velika reka, 14.06.1986, 6ɗ 4Ψ, leg. Vujić; Jasle- Jablanova ravan, 14.06.1986, 17ɗ 4Ψ, leg. Bożičić, Šimić, Vujić; Jablanova ravan, 0 4.07.1986, 2Ψ, leg. Radišić, Vujić; Jankove bare, 15.06.1986, 3ɗ, leg. Bożičić, Šimić, Vujić; 0 7.07.1986, 4Ψ, leg. Šimić; Marina voda, 15.06.1986, ɗ, leg. Bożičić; Pajino preslo, 18.06.1986, 4ɗ, leg. Bożičić, Šimić, Vujić; Duboka reka, 0 6.07.1986, 4Ψ, leg. Radišić, Radnović, Vujić; 18.06.1986, 4ɗ, leg. Bożičić, Šimić, Vujić; Bačište, 0 6.07.1986, ɗ Ψ, leg. Šimić; Karamanski potok, 0 7.07.1986, 14Ψ, leg. Radišić, Radnović, Vujić, 18.06.1996, 4Ψ leg. Radović, Tanurdżić; Sunčana dolina, 23.06.1991, Ψ, leg. Vujić); mountain Stara planina (Topli do Pilj, 25.06.1987, Ψ, leg. Vujić).</p> <p> <i>Pipiza quadrimaculata</i> can be distinguished from other <i>luteitarsis</i> group species by short and broad abdomen (tergite 4 more than 2 times wide as long, Figs. 17, 18), presence of pale spots on tergites 2 and 3 (Figs. 17, 18) and well defined marginal ridge of abdomen (Figs. 17, 18). In male, the body is predominately black haired. In female, frons lacks pollinose lateral spots (Fig. 3), body hairs are very short and wing is densely microtrichose.</p> <p> <b>Variability</b>: female mesoscutum can be from pale haired to almost entirely black haired; spots on tergites can be distinct but sometimes tergites 2 and (or) 3 more or less all black (Figs. 17, 18); basoflagellomere from pale brown to predominantly dark.</p> <p> <b>Distribution</b>: from Finland south to the Pyrenees, Bulgaria and the former Yugoslavia; through northern and central Europe into Russia as far as the Pacific (Sakhalin). Also, this species supposedly occurs in North America (Speight 2007).</p> <p> <b>Ecology</b> (based on Speight 2007): preferred environment: forest; conifer forest from the <i>Fagus / Picea</i> zone up into <i>Picea</i> forest; on occasion also in humid <i>Fagus</i> forest. Adult habitat and habits: tracksides, clearings and open, mature forest. Flowers visited: yellow composites; umbellifers; <i>Alliaria, Allium ursinum, Caltha, Cardamine, Cornus, Euphorbia, Fragaria, Malus, Meum, Potentilla, Ranunculus, Rubus, Salix, Sambucus, Sorbus aucuparia.</i> Flight period: end May/July, with occasional later specimens, especially at higher altitudes. Larva: not described, but Kula (1982) records larvae as overwintering among leaf litter on the floor of spruce (<i>Picea</i>) forest.</p> <p> On the Balkan Peninsula <i>Pipiza quadrimaculata</i> appears in localities at higher altitudes, up to 700m. The main habitats of this species are <i>Fagus</i> and <i>Picea</i> forests, especially near swamps, rivers and streams. This is the most numerous species from the <i>P. luteitarsis</i> group on the Balkans.</p>Published as part of <i>Vujić, Ante, Radenković, Sne Ž Ana & Polić, Dubravka, 2008, A review of the luteitarsis group of the genus Pipiza Fallén (Diptera: Syrphidae) with description of a new species from the Balkan Peninsula, pp. 33-46 in Zootaxa 1845</i> on pages 41-44, DOI: <a href="http://zenodo.org/record/183301">10.5281/zenodo.183301</a&gt

Leaching of Selected Elements From Coal Ash Dumping

Coal ash obtained by coal combustion in the “Nikola Tesla A” power plant in Obrenovac near Belgrade (Serbia) is suspended in river water then carried by a pipeline to a dump. In order to predict the leachability and possible environmental impact of selected elements due to ionic strength of river water, we extracted coal ash with distilled water and 0.002 M–2 M solutions of KNO3. The results show that changes in river water ionic strength could significantly influence pollution by calcium, chromium and manganese ions, but not by zinc, nickel and copper ions. In the case of lead, magnesium, arsenic and iron ions it is difficult to predict the effects of ionic strength on pollution processes in the vicinity of the dump. Further, pollution by cadmium ions is unlikely because extractable cadmium is not detectable within the applied ionic strength range

Fractionation and potential mobility of trace metals in Danube alluvial aquifer within an industrialized zone

Thirty-five alluvial sediments of the River Danube and 12 groundwater samples were taken within the Panevo Oil Refinery (Serbia). The results for groundwater samples exceed European primary drinking water standards for Fe (obtained results, > 200 mu g/l) and Mn (obtained results, > 50 mu g/l), while the levels of the trace metals are below the thresholds for drinking water quality. Sediments were treated by sequential extraction procedure with five different solutions, each having a higher extraction capacity than the previous one. We also wanted to determine the possible relationships among trace metals and between sediment properties and elemental concentrations. These solutions partitioned metals into CH(3)COONH(4) extractable (F1); HCl carbonate extractable and NH(2)OH center dot HCl easily reducible (F2); (NH(4))(2)C(2)O(4)/H(2)C(2)O(4) moderately reducible (F3); H(2)O(2)-HNO(3) organic/sulfide extractable fractions (F4); and HCl acid-soluble residue (F5). The sum of trace metals Ni, Pb, Cu, and Zn associated with the first two fractions (exchangeable, carbonate, and easily reducible) is significant and extremely important because it represents the proportion of heavy metals that can be easily remobilized by changes in environmental conditions such as pH, redox potential, salinity, etc. Sediments located nearer the groundwater flow are exposed to stronger groundwater fluctuation and had a higher quantity of amorphous and less stable substrates of trace metals. Principal component analysis was used to understand and visualize the associations between the trace metals and certain geological forms within analyzed sediments. The observed association between Cr with total sulfur and Mn from the acid-soluble residue could indicate that Cr is in the form of reduced, less toxic Cr(III), which is from the ecochemical point of view very important

Optimizacija parametara laserske površinske obrade u cilju poboljšanja mehaničkih osobina austenitnih materijala

Prikazano tehničko rešenje se primenjuje za poboljšanje mehaničkih osobina delova izrađenih od austenitnih materijala, pre svega superlegura nikla, koji se koriste za rad na povišenim temperaturama i pritiscima. Visoke radne temperature i pritisci zahtevaju što veću otpornost na zamor i koroziju, bolje mehaničke osobine, i osobine i strukturu površinskog sloja. Uvođenjem definisanih parametara laserske površinske obrade, odnosno optimizacijom parametara, postižu se optimalni rezultati u pogledu mikrostrukture, površinske morfologije i topografije, tvrdoće, a time i na osobine materijala: dinamičku čvrstoću, koroziju, mehaničke osobine i drugo. Oblast primene datog tehničkog rešenja se odnosi pre svega na avioindustriju, automobilsku industriju i energetiku, ali se data rešenja mogu uspešno primeniti i u nuklearnoj industriji

The plant communities of classes Hydrochari-lemnetea Oberd. 1967 and Potametea tx. Et Prsg. 1942 of the Labudovo okno locality (Serbia)

Labudovo okno locality (50 m-84 m elevation) is situated in the south-eastern part of the edge of the Pannonian Plains, resting along the left bank of the Danube between 1982 km and 1078 km. The investigated locality is the result of rise of the Danube level after dam building of the hydroelectric power station Đerdap I. The vegetation comprises aquatic associations of the classes Hydrochari-Lemnetea Oberd. 1967 and Potametea Tx. et Prsg. 1942. The class Hydrochari-Lemnetea Oberd. 1967 includes the following phytocoenoses: Lemno-Spirodeletum W. Koch 1954, Salvinio-Spirodeletum polyrrhizae Slavnić 1956, Lemno minoris-Azolletum filiculoides Br.-Bl. 1952, Ceratophylletum demersi (Soó 27) Hild 1956. The class Potametea Tx. et Prsg. 1942 includes the associations Myriophyllo-Potametum Soó 1934, Nympaeetum albo-luteae Nowinski 1928, Trapetum natantis Mülleret Görs 1960

Severe Lipoatrophy in a Patient With Type 2 Diabetes in Response to Human Insulin Analogs Glargine and Degludec: Possible Involvement of CD4 T Cell–Mediated Tissue Remodeling

CASE SUMMARY A female patient age 69 years with .10-year history of type 2 diabetes (T2D), on a therapy of premixed aspart insulin, presented with poor glycemic control (HbA1c 8.7%). Change of therapy to three injections of short- acting aspart and once-daily glargine improved glycemic control but resulted in severe lipoatrophy at all sites of injection, a rare complication of insulin therapy almost exclusively associated with type 1 diabetes (T1D). The patient had C-peptide levels within normal range and lacked autoantibodies against GAD, islet antigen 2 (IA-2), and tissue transglutaminase (tTg), excluding T1D. Glargine injection was replaced by degludec, but this did not prevent formation of new indentures. Histological analysis of tissue biopsies revealed strong tissue remodeling at affected sites including fibrosis, reduction of adipocyte size, and increased vascularization. Immunohistochemical staining showed a strong influx of CD4 T cells in affected sites but no apparent signs of T cell–mediated cell death. Flow cytometry of peripheral blood leukocytes did not show an overt effector cell profile of CD4 T cells, indicating that the response was mediated locally. Our findings indicate that insulin-induced lipoatrophy in the context of T2D is distinct from that seen in T1D and appears to depend on CD4 T cell–mediated tissue remodeling

Histological characteristics of sugar beet leaves potentially linked to drought tolerance

Water is becoming more and more limiting factor of sugar beet production and the productivity of the crop can be significantly improved by increased drought tolerance. It is therefore a great challenge to assess the degree of variability of anatomical and morphological traits of breeding material with respect to water use efficiency and drought, that can be used as potential markers for selection of sugar beet genotypes with better tolerance to water shortage. To achieve this, the first step is to assess the degree of genetic variability with respect to anatomical and histological features linked to water management in plants, under optimal water supply. Comparative histiological analysis of lamina and petiole was done on 12 sugar beet genotypes which previously showed divergent responses to lack of water in the field. The plants were grown in semi-controlled conditions of a glasshouse, and watered daily. Mircromorphological analyses were done to assess leaf epidermal characteristics, by both light and SEM, and lamina and petiole histological features. The measurements were used to calculate the percentage of individual tissues in relation to the thickness of the lamina, main vein area and petiole area. The general structure of sample variability was established by principal component analysis (PCA), based on correlation matrix. In majority of genotypes the ratio of the size of cells of spongy parenchyma and palisade cells in average was 80%. Low genotypic variability of the studied histological parameters of the lamina and petiole may reflect the narrow genetic base of tested breeding material. The most significant genotypic difference, considering leaf epidermal tissue, was in % of adaxial and abaxial epidermis. The highest found number of stomata per mm(2) on both adaxial and abaxial epidermis was 40% higher than the lowest. During water stress, when stomata are closed, plant survival depends on the amount of water lost through the cuticle. SEM analysis of adaxial epidermis of the lamina show that cuticle varies in texture. Considering the observed genotypic variability in cuticle ornamentation and the fact that plants develop various strategies of adaptation to drought, finding genotypes with increased drought tolerance could be based on the characteristics of the cuticle and epidermis