Axial light emission and Ar metastable densities in a parallel plate dc micro discharge in steady state and transient regimes

Axial emission profiles in a parallel plate dc micro discharge (feedgas: argon; discharge gap d=1mm; pressure p=10Torr) were studied by means of time resolved imaging with a fast ICCD camera. Additionally, volt-ampere (V-A) characteristics were recorded and Ar* metastable densities were measured by tunable diode laser absorption spectroscopy (TDLAS). Axial emission profiles in the steady state regime are similar to corresponding profiles in standard size discharges (d=1cm, p=1Torr). For some discharge conditions relaxation oscillations are present when the micro discharge switches periodically between low current Townsend-like mode and normal glow. At the same time the axial emission profile shows transient behavior, starting with peak distribution at the anode, which gradually moves towards the cathode during the normal glow. The development of argon metastable densities highly correlates with the oscillating discharge current. Gas temperatures in the low current Townsend-like mode (T= 320-400K) and the high current glow mode (T=469-526K) were determined by the broadening of the recorded spectral profiles as a function of the discharge current.Comment: submitted to Plasma Sources Sci. Techno

Lawton, Michael T: Seven aneurysms: Tenets and techniques for clipping: Thieme 2011, ISBN 978-1-60406-054-6

In this paper, the removal of methylene blue (MB) from aqueous solution by biosorption onto apricot shellshas been investigated through batch experiments. Apricot shells were chosen as a locally available and abundant waste from fruit juice industry. Methylene blue is common pollutant of waste waters from textile industry. The influence of initial MB concentration on biosorption process has been studied. The experimental data have been analysed using Langmuir and Freundlichisotherm models. The Langmuir model better fits to experimental data, which explain monolayer adsorption. Maximum biosorption capacity is 24,31 mg/g. A comparison of the biosorption capacity of waste apricot shells with biosorption capacities of similar adsorbents previously investigated indicates that apricot shells could be a promising biosorbent for removal of MB from aqueous solution

Oscillation modes of dc microdischarges with parallel-plate geometry

Two different oscillation modes in microdischarge with parallel-plate geometry has been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier Transform Spectra of relaxation oscillations reveal chaotic behaviour of microdischarge. Volt-Ampere characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge and normal glow. However, free-running oscillations appear in subnormal glow only.Comment: Submitted to: New Journal of Physic

Long-range electronic reconstruction to a dxz,yzd_{xz,yz}-dominated Fermi surface below the LaAlO3_3/SrTiO3_3 interface

Low dimensionality, broken symmetry and easily-modulated carrier concentrations provoke novel electronic phase emergence at oxide interfaces. However, the spatial extent of such reconstructions - i.e. the interfacial "depth" - remains unclear. Examining LaAlO$_3$/SrTiO$_3$ heterostructures at previously unexplored carrier densities $n_{2D}\geq6.9\times10^{14}$ cm$^{-2}$, we observe a Shubnikov-de Haas effect for small in-plane fields, characteristic of an anisotropic 3D Fermi surface with preferential $d_{xz,yz}$ orbital occupancy extending over at least 100~nm perpendicular to the interface. Quantum oscillations from the 3D Fermi surface of bulk doped SrTiO$_3$ emerge simultaneously at higher $n_{2D}$. We distinguish three areas in doped perovskite heterostructures: narrow ($<20$ nm) 2D interfaces housing superconductivity and/or other emergent phases, electronically isotropic regions far ($>120$ nm) from the interface and new intermediate zones where interfacial proximity renormalises the electronic structure relative to the bulk.Comment: Supplementary material available at Scientific Reports websit

Optimization of hydrothermal carbonization process of grape pomace and application of obtained hydrochar

Predmet ovog rada je razvoj i optimizacija procesa hidrotermalne karbonizacije komine grožđa i ispitivanje mogućnosti upotrebe dobijene hidročađi kao adsorbensa olova iz vodenih rastvora. U cilju optimizacije procesa, ispitan je uticaj reakcione temperature na transformaciju biomase, primenom različitih fizičko-hemijskih metoda karakterizacije dobijenih proizvoda karbonizacije na 180, 200 i 220 °C. Hidrotermalno indukovane strukturne promene u dobijenim hidročađima su okarakterisane ispitivanjem fizičko-hemijskog sastava, gorivnih karakteristika, kao i primenom termogravimetrijske, morfološke i spektroskopske analize, dok je u procesnim vodama određen sadržaj neorganskih elemenata, urađena spektroskopska analiza, analiza sadržaja pojedinačnih organskih komponenti i ispitan antioksidativni potencijal. Dobijeni rezultati su pokazali da između dobijenih hidročađi postoje bitne strukturne razlike. Utvrđeno je da hidrotermalna degradacija hemiceluloze i celuloze, uzrokovana povećanjem temperature karbonizacije u najvećoj meri indukuje strukturne promene biomase tokom konverzije. Hidročađ koja poseduje značajan energetski potencijal, povećan sadržaj ugljenika i aromatičnost, kao i mogućnost re-adsorpcije pojedinih neorganskih elemenata dobijena je karbonizacijom na 220 °C. Takođe, povećanje reakcione temperature dovodi do porasta sadržaja fenola, polifenolnih jedinjenja i organskih molekula u procesnim vodama, dok istovremeno uzrokuje opadanje antioksidativne aktivnosti, ukupnog sadržaja antocijana i organskih kiselina. Mogućnost upotrebe hidročađi kao biosrbenta ispitana je sa aspekta adsorpcije Pb2+ jona iz vodenih rastvora. Kako bi se izabrao uzorak sa najboljim adsorpcionim kapacitetom izvršena su preliminarna ispitivanja procesa adsorpcije Pb2+ jona primenom hidročađi dobijenih na tri pomenute reakcione temperature. Dobijeni rezultati su ukazali da hidročađ dobijena na 220 °C pokazuje najbolji adsorpcioni kapacitet (27,8 mg/g), pa je stoga ova hidročađ izabrana za detaljna ispitivanja procesa adsorpcije Pb2+ jona...The subject of this work was the development and optimization of hydrothermal carbonization of grape pomace and investigation of potential applications of the obtained hydrochar as adsorbent of lead from aqueous solutions. In order to optimize the process, influence of the reaction temperature on transformation of biomass was investigated using different physico-chemical characterization methods of the products obtained at 180, 200 and 220 °C. Hydrothermal induced structural changes in hydrochars were elucidated by examination of physico-chemical composition, fuel characteristics, using thermogravimetric, morphological and spectroscopic analysis. IR spectroscopy, analysis of inorganic, as well as organic compounds, and antioxidant assays, were used for process waters characterization. The results showed significant structural differences between the obtained products. It has been found that degradation of hemicellulose and cellulose, caused by temperature increase, governs the most significant structural changes in biomass during carbonization. The formation of hydrochar with significant energy potential, increased carbon content and the best adsorption ability, but decreased H/C ratio was achieved at 220 °C. Also, at higher temperature an increase in total phenolic and organic content in process waters was observed, while total antioxidative capacity, anthocyanin and organic acid content simultaneously decreased. Application of the obtained hydrochars was tested via adsorption of Pb2+ ions from aqueous solution. In order to select material with the best adsorption ability, preliminary studies of Pb2+ sorption using hydrochars obtained at three aforementioned reaction temperatures were performed. Obtained results indicated that hydrochar produced at 220 °C exhibited the best adsorption potential (27.8 mg/g), and therefore this sample was chosen for further investigations of Pb2+ removal..

DELLA protein regulation during shade avoidance

Shade avoidance responses are suit of adaptive reactions for gaining sufficient light by plants grown in shading conditions. This phenomenon consists of enhanced elongation of shoot-like organs, upward movements of leaves and accelerated flowering and fruit-set. Adaptive reactions result from the activity of many plant growth regulators. Our study was focused on DELLA proteins which are components of gibberellin (GA) plant hormone signaling in regulating shade avoidance of Arabidopsis petioles and hypocotyls. We confirmed the involvement of these proteins in GA-regulated shade avoidance and showed interaction of these proteins with auxin and ethylene which partly regulates shade avoidance responses

Significance of combined therapy of heparine and exercise in patients with refractory angina pectoris

Terapijska arteriogeneza predstavlja novu terapijsku opciju za ove bolesnike sa refraktornom ishemijkom koronarnom bolesti. Cilj terapijske arteriogeneze je da indukuje stvaranje novih krvnih sudova koji mogu da poboljšaju protok krvi u regionima koji nemaju adekvatno snabdevanje krvlju. Našim istraživenjem očekujemo da tokom perioda praćenja bolesnici koji budu dobijali heparin (H) zajedno sa fizičkim opterećenjem imaju više izraženu koronarnu arteriogenezu i kolateralnu cirkulaciju, manje tegoba po tipu stabilne srčane angine i manju ishemiju srčanog mišića na stresnoj ehokardiografiji. Ciljevi: ove studije, koja je uključivala bolesnike sa refraktornom srčanom anginom koji nisu kandidati za revaskularizaciju, su da se: 1. Proceni težina stabilne srčane angine pre i nakon fizičkog treninga. 2. Izračuna indeks pokretljivosti zidova leve komore pri maksimalnom opterećenju tokom stres egokardiografskog testa opterećenjem pre i nakon fizičkog treninga. 3. Proceni kolateralna cirkulacija na MSCT koronarnoj angiografiji pre i nakon fizičkog treninga. Materijal i metode: Naša studija je obuhvatila 32 bolesnika sa hroničnom stabilnom anginom pektoris refraktornom na optimalnu medikamentnu terapiju, koji nisu kandidati za perkutanu i/ili hiruršku revaskularizaciju (tzv. ''no-option” bolesnici). Kao drugi kriterijum za uključenje u studiju bolesnici su morali biti sposobni da vežbaju. Ovi pacijenti su se u periodu od 2013. do 2019. godine lečili na Klinici za kardiologiju Kliničkog Centra Srbije. Bolesnici su bili randomizovani u 2 grupe (po 16 bolesnika u svakoj grupi). Grupa 1 (placebo+vežbanje, P+E), bolesnici koji su podvrgnuti standardnoj fizikalnoj rehabilitaciji (iv. Placebo 10 minuta pre svake od 2 dnevne sesije fizičkog treninga koji se održava 5 dana nedeljno tokom 2 nedelje). Kao placebo injekciju koristili smo intravensku injekciju od 2 ml sa fiziološkim rastvorem (0,9% NaCl). Grupa 2 (heparin+vežbanje, H+E), bolesnici koji su bili podvrgnuti standardnoj fizikalnoj rehabilitaciji sa prethodnom primenom leka (isto kao prethodna grupa ali sa heparinom 100 ij/kg do maksimalne doze od 5000 ij iv. 10 minuta pre fizičkog treninga)...Therapeutic arteriogenesis represents a new therapeutic option for patients with refractory cardiac angina. The goal of therapeutic arteriogenesis is to induce the formation of new blood vessels that can improve blood flow in regions that do not have adequate blood supply. In our study, we expect that during the follow-up period, patients receiving heparin (H), together with physical activity (exercise, E), have a more pronounced coronary arteriogenesis and collateral circulation, less severe type of stable cardiac angina, and less cardiac muscle ischemia on stress echocardiography. The aims: of the present study, which included patients with refractory cardiac angina who were not candidates for revascularization, was to: 1. Assess the severity of stable cardiac angina before and after physical training. 2. Calculate the peak stress wall motion score index of the left ventricule during stress echocardiography testing before and after physical training. 3. Assess collateral circulation by MSCT coronary angiography before and after physical training. Matherial and methods: Our study included 32 patients with chronic stable angina pectoris refractory to optimal medicament therapy, who are not candidates for percutaneous and/ or surgical revascularization (so-called 'no option' patients). As a second criterion for inclusion in the study, patients had to be able to exercise. From 2013 to 2019, these patients were treated at the Cardiology Clinic of the Clinical Center of Serbia. Patients were randomized into 2 groups (16 patients in each group). Group 1 (placebo, P + exercise, E), patients undergoing standard physical rehabilitation (iv. placebo 10 minutes before each 2-day physical training session, held 5 days per week for 2 weeks). We used intravenous injection of 2 ml saline (0.9% NaCl) as a placebo injection. Group 2 (heparin, H + exercise, E), patients undergoing standard physical rehabilitation with heparin pretraetment (same exercise as the previous group but with heparin 100 IU/ kg to maximum doses of 5000 IU iv. administration 10 minutes before physical training). All patients underwent an echocardiographic examination and exercise stress echocardiography testing according to the standard Bruce protocol before starting the training and at the end of a 2-week training cycle..

Rheological Modeling of Yarn Elongation

Na temelju eksperimentalnih podataka dobivenih za istezanje pređe u standardnim uvjetima ispitivanja, kombinacijom poznatih elementarnih reoloških modela, postavljenih reoloških modela istezanja pređe, izvedene su i riješene odgovarajuće diferencijalne jednadžbe za ispitivane pređe. Time je dobivena ovisnost između jedinične sile (naprezanja) i relativnog istezanja. Modeli su postavljeni za tri vrste pređe: vunena pređa finoće 21 tex prosječnog broja uvoja 1646 m-1 uz koeficijent varijacije 6,78%, pamučna pređa finoće 10 tex prosječnog broja uvoja 1020 m-1 uz koeficijent varijacije 16,7 i pređa od mješavine vuna/PES 76/24% finoće 12,5 tex prosječnog broja uvoja 1080 m-1.Based on the experimental data obtained for yarn elongation in standard test conditions, by combination of known elementary rheological models and established rheological models of yarn elongation, differential equations for the tested yarns were derived and solved. Thereby, the dependence between unit force (stress) and relative elongation was obtained. The models were established for three types of yarn: wool yarn with a count of 21 tex of anaverage twist level of 1,646 m-1 with a variation coefficient of 6.78%, cotton yarn with a count of 10 tex of an average twist level of 1,020 m2 with a variation coefficient of 16.7% and wool/PES blend yarn 76/24% with a count of 12.5 tex and an average twist level of 1,080 min-1

Side-detection of out-coupled core light from a microfluidic fiber microslit

The interactions of the core-propagating light with an intersecting microslit within a conventional single-mode fiber are investigated. Orientation-dependent out-coupling of core light was utilized to create side-detection, miniature fiber rotation sensors