Search results for "Kali"
showing 10 items of 823 documents
Analysis of self-trapped hole mobility in alkali halides and metal halides
2017
Support from Latvian National Research Program IMIS2 (2014–2017) and LZP Grant No. 237/2012 (2013–2016) is greatly appreciated.
Photosensitivity of SiO2–Al and SiO2–Na glasses under ArF (193 nm) laser
2009
Abstract Photosensitivity of SiO 2 –Al and SiO 2 –Na glass samples was probed by means of the induced optical absorption and luminescence as well as by electron spin-resonance (ESR) after irradiation with excimer-laser photons (ArF, 193 nm). Permanent visible darkening in the case of SiO 2 –Al and transient, life time about one hour, visible darkening in the case of SiO 2 –Na was found under irradiation at 290 K. No darkening was observed at 80 K for either kind of material. This investigation is dedicated to revealing the electronic processes responsible for photosensitivity at 290 and 80 K. The photosensitivity of both materials is related to impurity defects excited directly in the case …
A new neuraminic acid derivative and three types of glycopeptides isolated from the Cuvierian tubules of the sea cucumber Holothuria forskali
1973
The Cuvierian tubules of Holothuria forskali Della Chiaje, a sea cucumber found in the Adriatic Sea, were investigated with regard to their carbohydrate moieties. From a Pronase digest of these tubules three types of carbohydrate units were isolated and characterized. 1. A high-molecular-weight glycopeptide fraction was shown to contain sulphated polyfucose, galactosamine, a uronic acid and a previously unknown neuraminic acid derivative. The sulphate was shown by i.r. analysis to be present as an O-ester. The carbohydrate unit was linked O-glycosidically to threonine and serine residues in the polypeptide chain. The hitherto unknown neuraminic acid derivative (Hf-neuraminic acid) was resis…
Detection of primary DNA damage in Chlamydomonas reinhardtii by means of modified microgel electrophoresis.
1997
The assessment of genotoxic potential in surface water requires test methods, among which are those that detect initial DNA damage in organisms of aquatic biocenosis. The microgel electrophoresis (MGE) "comet assay" was applied to a ubiquitous unicellular green alga (Chlamydomonas reinhardtii) to detect DNA damage caused by genotoxins. For this, the test protocol described by Singh NP et al. [Exp Cell Res 175: 184-191, 1988] was modified. Major modifications were the use of alkaline lysis buffer with ionic detergents and the reduction of preincubation and electrophoresis times. Short-time exposure of Chlamydomonas to the well-known genotoxicants 4-nitroquinoline-1-oxide (4-NQO), N-nitrosodi…
A Multi-Position Calibration Method for Consumer-Grade Accelerometers, Gyroscopes, and Magnetometers to Field Conditions
2017
This paper presents a calibration method for consumer-grade accelerometers, gyroscopes, and magnetometers. Considering the calibration of consumer-grade sensors, it is essential that no specialized equipment is required to create reference signals. In addition, the less is required from the reference signals, the more suitable the method is on the field. In the proposed method, the novelty in the calibration of the gyroscopes lies in the exploitation of only the known net rotations between the positions in a multi-position calibration. For accelerometers and magnetometers, the innovation is that the direction of reference signals, the gravity and the magnetic field of the Earth, are estimat…
A method for measuring low-weight carboxylic acids from biosolid compost
2006
Concentration of low-weight carboxylic acids (LWCA) is one of the important parameters that should be taken into consideration when compost is applied as soil improver for plant cultivation, because high amounts of LWCA can be toxic to plants. The present work describes a method for analysis of LWCA in compost as a useful tool for monitoring compost quality and safety. The method was tested on compost samples of two different ages: 3 (immature) and 6 (mature) months old. Acids from compost samples were extracted at high pH, filtered, and freeze-dried. The dried sodium salts were derivatized with a sulfuric acid–methanol mixture and concentrations of 11 low-weight fatty acids (C1–C10) were a…
Free and bound chlorophenols in kraft pulp bleaching effluents
1992
Abstract Free (F; hexane extractable) and chemically bound (B; alkali extractable) chlorophenols, catechols and guaiacols were measured from effluents of the C and E stages of chlorobleaching of kraft softwood pulp. Ratio B/F was in moste cases nearly one, but for tetrachloroguaiacol B/F was 20 in C and 2.70 in E stage. Organically bound chlorine (OCl) in chlorophenols was less than one percent of the total AOX (Adsorbable Organic Halogen) emitted.
Specific detection of cyclobutane pyrimidine dimers in phytoplankton DNA by a non-radioactive assay based on T4-endonuclease V digestion.
2001
The effect of artificial and natural UV irradiation on DNA in marine phytoplankton Isochrysis galbana monoculture was investigated. The presence of cyclobutane pyrimidine dimers (CPDs) in unlabelled I. galbana DNA was detected by a non-radiometric alkaline filter elution assay after T4-endonuclease V digestion. The quantity of CPDs was estimated by alkaline agarose gel electrophoresis. Precise determination of the amount of DNA in the presence of I. galbana pigments was achieved by oxazole yellow homodimer (YOYO) dye. T4-endonuclease V-sensitive sites frequency (ESS/kb), measured after exposure to 2-40 kJ m(-2) of artificial UV light, increased in a dose-dependent manner. Twelve hours after…
Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants
2012
During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χ(fd)), and temperature dependence of magnetic susceptibility. Mineralogical and geochemical analyses included scanning electron microscopy with energy dispersive spectroscopy, microprobe analysis and X-ray diffraction. The TMPs in fly ash from hard coal combustio…
Organic material dissolved during oxygen-alkali pulping of hot-water-extracted spruce sawdust
2016
Untreated and hot-water-extracted (HWE) Norway spruce (Picea abies) sawdust was cooked using the sulfur-free oxygen-alkali (OA) method under the following conditions: temperature, 170 °C; liquor-to-wood ratio, 5:1 L/kg; and NaOH charge, 19% on the oven-dry sawdust. In comparison with earlier studies conducted with birch sawdust, the spruce cooking yield data, together with the amount of the pulp rejects (78% to 86% for reference pulps from the initial feedstock and 73% to 83% for pulps from the HWE feedstock), revealed that the pretreatment stage prior to spruce OA pulping caused different effects on pulping performance. The analyses of the three main compound groups (i.e., lignin, volatile…