Assessment of Coals from Russia and Countries of Former Soviet Union for Utility Fluidized Bed Boilers

With the occurrence of fossil fuels such as oil, gas and coal we found new sources of energy that have played a critical role in the progress of our modern society. Coal is very ample compared to the other two fossil fuels. Global coal reserves at the end of 2005 were estimated at 847,5 billion tones. Along with the major energy sources, coal is the most fast growing fuel on a global basis, it provides 26% of primary energy needs and remains essential to the economies of many developed and developing countries. Coal-fired power generation accounts for 41% of the world‘s total electricity production and in some countries, such as South Africa, Poland, China, Australia, Kazakhstan and India is on very high level. Still, coal utilization represents challenges related to high emissions of air pollutants such as sulphur and nitrogen dioxides, particulate matter, mercury and carbon dioxide. In relation to these a number of technologies have been developed and are in marketable use, with further potential developments towards ―Near Zero Emission‖ coal plants. In present work, coals mined in Russia and countries of Former Soviet Union were reviewed. Distribution of coal reserves on the territory of Russia and the potential for power generation from coal-fired plants across Russia was shown. Physical and chemical properties of coals produced were listed and examined, as main factor influencing on design of the combustion facility and incineration process performance. The ash-related problems in coal-fired boilers were described. The analysis of coal ash of Russia and countries of Former Soviet Union were prepared. Feasible combustion technologies also were reviewed.

Determination of Hg in water by CVAAS using 2-aminothiazole modified silica

This paper discusses a rapid and sensitive method developed to determine trace levels of mercury in natural water samples by cold vapor atomic absorption spectrometry using a preconcentration system composed by mini-column packed with 100 mg of 2-aminothiazol modified silica gel (SiAT) coupled on-line with the spectrometer's cold vapor generator system. The optimum preconcentration conditions are also described here. The preconcentrated Hg(II) ions were eluted directly from the column to the spectrometer's cold vapor generator system using 100 µL of 2 mol L-1 hydrochloric acid and the retention efficiency achieved exceeded 95%. The enrichment factors determined were 29, 38 and 46 using 3, 4 and 5 mL of preconcentrated aqueous solutions containing 400 ng L-1 of Hg. The detection limit calculated was 5 ng L-1. The preconcentration procedure was applied to determine trace level mercury in spiked river water samples.

Interaction study of moxifloxacin with Cu(II) ion using square-wave voltammetry and its application in the determination in tablets

This work presents an electroanalytical method for the determination of moxifloxacin (MOXI) in tablets by its interaction with Cu(II) ion and subsequent electrochemical reduction at hanging mercury drop electrode (HMDE). A well-defined reduction peak at -0.21 V vs. Ag/AgCl in Phosphate buffer 0.04 mol L-1 pH 8.0 was observed for the complex reduction MOXI-Cu(II), using square-wave voltammetry (SWV). Using a 10 s of accumulation time at -0.40 V was found a limit detection of 3.60x10-8 mol l-1. The obtained results have shown good agreement with those obtained by spectrophotometric method.

Argentimetric assay of ranitidine in bulk drug and in dosage forms

Two simple, rapid and cost-effective methods based on titrimetric and spectrophotometric techniques are described for the assay of RNH in bulk drug and in dosage forms using silver nitrate, mercury(II)thiocyanate and iron(III)nitrate as reagents. In titrimetry, an aqueous solution of RNH is treated with measured excess of silver nitrate in HNO3 medium, followed by determination of unreacted silver nitrate by Volhard method using iron(III) alum indicator. Spectrophotometric method involve the addition a known excess of mercury(II)thiocyanate and iron(III)nitrate to RNH, followed by the measurement of the absorbance of iron(III)thiocyante complex at 470 nm. Titrimetric method is applicable over 4-30 mg range and the reaction stoichiometry is found to be 1:1 (RNH: AgNO3). In the spectrophotometric method, the absorbance is found to increase linearly with concentration of RNH which is corroborated by the correlation coefficient of 0.9959. The system obey Beer's law for 5-70 µg mL-1. The calculated apparent molar absorptivity and sandell sensitivity values are found to be 3.27 ´ 10³ L mol-1 cm-1, 0.107 µg cm-2 respectively. The limits of detection and quantification are also reported for the spectrophotometric method. Intra-day and inter-day precision and accuracy of the methods were evaluated as per ICH guidelines. The methods were successfully applied to the assay of RNH in formulations and the results were compared with those of a reference method by applying Student's t and F-tests. No interference was observed from common pharmaceutical excipients. The accuracy of the methods was further ascertained by performing recovery tests by standard addition method.

Electrochemical study and dependence of 'transition state' in Co(II) and Ni(II) complexes with some antibiotics and cephalothin

Electrode kinetics and study of 'transition state' with applied potential in case of [M - antibiotics - cephalothin] system were reported at pH = 7.30 ± 0.01 at suitable supporting electrolyte at 25.0ºC. The M = Co or Ni and antibiotics were doxycycline, chlortetracycline, oxytetracycline, tetracycline, minocycline, amoxicillin and chloramphenicol used as primary ligands and cephalothin as secondary ligand. Kinetic parameters viz. transfer coefficient (a), degree of irreversibility (l), diffusion coefficient (D) and rate constant (k) were determined. The values of a and k varied from 0.41 to 0.59 and 2.60 X 10-3 cm s-1 to 9.67 X 10-3 cm s-1 in case of [Co - antibiotics - cephalothin] system. In case of [Ni - antibiotics - cephalothin], a and k varied from 0.41 to 0.58 and 2.34 X 10-3 cm s-1 to 9.19 X 10-3 cm s-1 respectively confirmed that transition state behaves between oxidant and reductant response to applied potential and it adjusts it self in such a way that the same is located midway between dropping mercury electrode and solution interface. The values of rate constant confirmed the quasireversible nature of electrode processes. The stability constants (logb) of complexes were also determined.

Spectrophotometric determination of arsenic in soil samples using 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol (Br-PADAP)

In this paper, a new, simple and sensitive method for arsenic determination in soil is proposed. This is based on the reduction of silver (I) and iron (III) ions by arsine followed by a complexation reaction of iron (II) with the spectrophotometric reagent Br-PADAP 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol. Arsenic determination with a Sandell's sensitivity of 3.1 10-4 cm-2, linear range from 0.1 µg ml-1 to 2.0 µg ml-1 (r560 = 0.9995), molar absorptivity of 2.45 10(5) l mol-1 cm-1 and a concentration detection limit of 1.4 ng ml-1 (3s) were obtained using a 10 ml sample volume. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for arsenic determination in the presence of several ions amounts in digested soil samples. The results revealed that antimony (III), mercury (II), germanium (IV), platinum (IV) interferes at all analyzed proportions. The interferences can be easily removed by the use of EDTA. Precision and accuracy obtained were satisfactory with a R.S.D. < 5 %. Recovery of arsenic in soil samples varied from 95.55 to 102.70 % with a mean of 99.63 %. These results demonstrated that the proposed method is applicable for arsenic analysis in different soil samples.

Optimal trading of wind power in the short term market

The energy reform, which is happening all over the world, is caused by the common concern of the future of the humankind in our shared planet. In order to keep the effects of the global warming inside of a certain limit, the use of fossil fuels must be reduced. The marginal costs of the renewable sources, RES are quite high, since they are new technology. In order to induce the implementation of RES to the power grid and lower the marginal costs, subsidies were developed in order to make the use of RES more profitable. From the RES perspective the current market is developed to favor conventional generation, which mainly uses fossil fuels. Intermittent generation, like wind power, is penalized in the electricity market since it is intermittent and thus diffi-cult to control. Therefore, the need of regulation and thus the regulation costs to the producer differ, depending on what kind of generation market participant owns. In this thesis it is studied if there is a way for market participant, who has wind power to use the special characteristics of electricity market Nord Pool and thus reach the gap between conventional generation and the intermittent generation only by placing bids to the market. Thus, an optimal bid is introduced, which purpose is to minimize the regulation costs and thus lower the marginal costs of wind power. In order to make real life simulations in Nord Pool, a wind power forecast model was created. The simulations were done in years 2009 and 2010 by using a real wind power data provided by Hyötytuuli, market data from Nord Pool and wind forecast data provided by Finnish Meteorological Institute. The optimal bid needs probability intervals and therefore the methodology to create probability distributions is introduced in this thesis. In the end of the thesis it is shown that the optimal bidding improves the position of wind power producer in the electricity market.

Observations on the Pharmacokinetics and Pharmacodynamics of Dexmedetomidine. Clinical Studies on Healthy Volunteers and Intensive Care Patients

Patients treated in intensive care units require sedation and analgesia. However, sedative drugs also have potential adverse effects, and there is no single ideal sedativeanalgesic drug for these patients. Dexmedetomidine is an apha2-adrenoceptor agonist licenced for sedation of intensive care patients and patients undergoing surgery and other invasive procedures. Several routes of parenteral administration (intravenous, intramuscular, subcutaneous and intranasal) have been utilized. In the present series of studies, the pharmacokinetics and pharmacodynamics of intranasally administered dexmedetomidine as well as the gastrointestinal effects of intravenous dexmedetomidine were determined in healthy volunteers. Pharmacokinetics of dexmedetomidine during long lasting, high-dose infusions were characterized in intensive care patients. The bioavailability of intranasal dexmedetomidine was relatively good (65%), but interindividual variation was large. Dexmedetomidine significantly inhibited gastric emptying and gastrointestinal transit. In intensive care patients, the elimination half-life of dexmedetomidine was somewhat longer than reported for infusions of shorter duration and in less ill patients or healthy volunteers. Dexmedetomidine appeared to have linear pharmacokinetics up to the studied dose rate of 2.5 μg/kg/h. Dexmedetomidine clearance was decreasing with age and its volume of distribution was increased in hypoalbuminaemic patients, resulting in a longer elimination half-life and context-sensitive half-time. Intranasally administered dexmedetomidine was efficacious and well tolerated, making it appropriate for clinical situations requiring light sedation. The clinical significance of the gastrointestinal inhibitory effects of dexmedetomidine should be further evaluated in intensive care patients. The possibility of potentially altered potency and effect duration should be taken into account when administering dexmedetomidine to elderly or hypoalbuminaemic patients.

Measurement systems of soil water matric potential and evaluation of soil moisture under different irrigation depths

The development of new methodologies and tools that enable to determine the water content in soil is of fundamental importance to the practice of irrigation. The objective of this study was to evaluate soil matric potential using mercury tensiometer and puncture digital tensiometer, and to compare the gravimetric soil moisture values obtained by tensiometric system with gravimetric soil moisture obtained by neutron attenuation technique. Four experimental plots were maintained with different soil moisture by irrigation. Three repetitions of each type of tensiometer were installed at 0.20 m depth. Based on the soil matric potential and the soil water retention curve, the corresponding gravimetric soil moisture was determined. The data was then compared to those obtained by neutron attenuation technique. The results showed that both tensiometric methods showed no difference under soil matric potential higher than -40 kPa. However, under drier soil, when the water was replaced by irrigation, the soil matric potential of the puncture digital tensiometer was less than those of the mercury tensiometer.

Oil Transportation in the Gulf of Finland in 2020 and 2030

This study is part of the Minimizing risks of maritime oil transport by holistic safety strategies (MIMIC) project. The purpose of this study is to provide a current state analysis of oil transportation volumes in the Baltic Sea and to create scenarios for oil transportation in the Gulf of Finland for the years 2020 and 2030. Future scenarios and information about oil transportation will be utilized in the modelling of oil transportation risks, which will be carried out as part of the MIMIC project. Approximately 290 million tons of oil and oil products were transported in the Baltic Sea in 2009, of which 55% (160 million tons) via the Gulf of Finland. Oil transportation volumes in the Gulf of Finland have increased from 40 million to almost 160 million tonnes over the last ten years. In Russia and Estonia, oil transportation mainly consists of export transports of the Russian oil industry. In Finnish ports in the Gulf of Finland, the majority of oil traffic is concentrated to the port of Sköldvik, while the remainder mainly consists of different oil products for domestic use. Transit transports to/from Russia make up small volumes of oil transportation. The largest oil ports in the Gulf of Finland are Primorsk, Tallinn, St. Petersburg and Sköldvik. The basis for the scenarios for the years 2020 and 2030 is formed by national energy strategies, the EU`s climate and energy strategies as well other energy and transportation forecasts for the years 2020 and 2030. Three alternative scenarios were produced for both 2020 and 2030. The oil volumes are based on the expert estimates of nine specialists. The specialists gave three volumes for each scenario: the expected oil transport volumes, and the minimum and maximum volumes. Variations in the volumes between the scenarios are not large, but each scenario tends to have rather a large difference between the figures for minimum and maximum volumes. This variation between the minimum and maximum volumes ranges around 30 to 40 million tonnes depending on the scenario. On the basis of this study, no a dramatic increase in oil transportation volumes in the Gulf of Finland is to be expected. Most of the scenarios only forecasted a moderate growth in maritime oil transportation compared to the current levels. The effects of the European energy policy favouring renewable energy sources can be seen in the 2030 scenarios, in which the transported oil volumes are smaller than in the 2020 scenarios. In the Slow development 2020 scenario, oil transport volumes for 2020 are expected to be 170.6 Mt (million tonnes), in the Average development 2020 187.1 Mt and in the Strong development 2020 201.5 Mt. The corresponding oil volumes for the 2030 scenarios were 165 Mt for the Stagnating development 2030 scenario, 177.5 Mt for the Towards a greener society 2030 scenario and 169.5 Mt in the Decarbonising society 2030 scenario.

The quality control of glycoprotein folding in the endoplasmic reticulum, a trip from trypanosomes to mammals

The present review deals with the stages of synthesis and processing of asparagine-linked oligosaccharides occurring in the lumen of the endoplasmic reticulum and their relationship to the acquisition by glycoproteins of their proper tertiary structures. Special emphasis is placed on reactions taking place in trypanosomatid protozoa since their study has allowed the detection of the transient glucosylation of glycoproteins catalyzed by UDP-Glc:glycoprotein glucosyltransferase and glucosidase II. The former enzyme has the unique property of covalently tagging improperly folded conformations by catalyzing the formation of protein-linked Glc1Man7GlcNAc2, Glc1Man8GlcNac2 and Glc1Man9GlcNAc2 from the unglucosylated proteins. Glucosyltransferase is a soluble protein of the endoplasmic reticulum that recognizes protein domains exposed in denatured but not in native conformations (probably hydrophobic amino acids) and the innermost N-acetylglucosamine unit that is hidden from macromolecular probes in most native glycoproteins. In vivo, the glucose units are removed by glucosidase II. The influence of oligosaccharides in glycoprotein folding is reviewed as well as the participation of endoplasmic reticulum chaperones (calnexin and calreticulin) that recognize monoglucosylated species in the same process. A model for the quality control of glycoprotein folding in the endoplasmic reticulum, i.e., the mechanism by which cells recognize the tertiary structure of glycoproteins and only allow transit to the Golgi apparatus of properly folded species, is discussed. The main elements of this control are calnexin and calreticulin as retaining components, the UDP-Glc:glycoprotein glucosyltransferase as a sensor of tertiary structures and glucosidase II as the releasing agent.

Methylmercury intoxication and histochemical demonstration of NADPH-diaphorase activity in the striate cortex of adult cats

The effects of methylmercury (MeHg) on histochemical demonstration of the NADPH-diaphorase (NADPH-d) activity in the striate cortex were studied in 4 adult cats. Two animals were used as control. The contaminated animals received 50 ml milk containing 0.42 µg MeHg and 100 g fish containing 0.03 µg MeHg daily for 2 months. The level of MeHg in area 17 of intoxicated animals was 3.2 µg/g wet weight brain tissue. Two cats were perfused 24 h after the last dose (group 1) and the other animals were perfused 6 months later (group 2). After microtomy, sections were processed for NADPHd histochemistry procedures using the malic enzyme method. Dendritic branch counts were performed from camera lucida drawings for control and intoxicated animals (N = 80). Average, standard deviation and Student t-test were calculated for each data group. The concentrations of mercury (Hg) in milk, fish and brain tissue were measured by acid digestion of samples, followed by reduction of total Hg in the digested sample to metallic Hg using stannous chloride followed by atomic fluorescence analysis. Only group 2 revealed a reduction of the neuropil enzyme activity and morphometric analysis showed a reduction in dendritic field area and in the number of distal dendrite branches of the NADPHd neurons in the white matter (P<0.05). These results suggest that NADPHd neurons in the white matter are more vulnerable to the long-term effects of MeHg than NADPHd neurons in the gray matter.

Decreased gastric emptying and gastrointestinal and intestinal transits of liquid after complete spinal cord transection in awake rats

We studied the effect of complete spinal cord transection (SCT) on gastric emptying (GE) and on gastrointestinal (GI) and intestinal transits of liquid in awake rats using the phenol red method. Male Wistar rats (N = 65) weighing 180-200 g were fasted for 24 h and complete SCT was performed between C7 and T1 vertebrae after a careful midline dorsal incision. GE and GI and intestinal transits were measured 15 min, 6 h or 24 h after recovery from anesthesia. A test meal (0.5 mg/ml phenol red in 5% glucose solution) was administered intragastrically (1.5 ml) and the animals were sacrificed by an iv thiopental overdose 10 min later to evaluate GE and GI transit. For intestinal transit measurements, 1 ml of the test meal was administered into the proximal duodenum through a cannula inserted into a gastric fistula. GE was inhibited (P<0.05) by 34.3, 23.4 and 22.7%, respectively, at 15 min, 6 h and 24 h after SCT. GI transit was inhibited (P<0.05) by 42.5, 19.8 and 18.4%, respectively, at 15 min, 6 h and 24 h after SCT. Intestinal transit was also inhibited (P<0.05) by 48.8, 47.2 and 40.1%, respectively, at 15 min, 6 h and 24 h after SCT. Mean arterial pressure was significantly decreased (P<0.05) by 48.5, 46.8 and 41.5%, respectively, at 15 min, 6 h and 24 h after SCT. In summary, our report describes a decreased GE and GI and intestinal transits in awake rats within the first 24 h after high SCT.

Total and segmental colonic transit time in constipated patients with Chagas’ disease without megaesophagus or megacolon

Manometric and pharmacological tests have shown that motor abnormalities may occur in the non-dilated colons of chagasic patients. In order to investigate the presence of abnormalities of colonic function in constipated patients with Chagas’ disease (ChC) without megaesophagus or megacolon, studies of total and segmental colonic transit time with radiopaque markers were performed on 15 ChC patients, 27 healthy volunteers and 17 patients with idiopathic constipation (IC). The values obtained for the control group were similar to those reported in the literature (total colonic time: 34.1 ± 15.6 h; right colon: 9.9 ± 7.3 h; left colon: 10.8 ± 10 h, and rectosigmoid: 12.6 ± 9.9 h). Colonic transit time data permitted us to divide both IC and ChC patients into groups with normal transit and those with slow colonic transit. Colonic inertia was detected in 41% of IC patients and in 13% of ChC patients; left colon isolated stasis (hindgut dysfunction) was detected in 12% of IC patients and 7% of ChC patients, and outlet obstruction was detected in 6% of IC patients and 7% of ChC patients. There were no significant differences in total or segmental colonic transit times between slow transit IC and slow transit ChC patients. In conclusion, an impairment of colonic motility was detected in about 30% of constipated patients with Chagas’ disease without megaesophagus or megacolon. This subgroup of patients presented no distinctive clinical feature or pattern of colonic dysmotility when compared to patients with slow transit idiopathic constipation.

Dietary fiber intake, stool frequency and colonic transit time in chronic functional constipation in children

The objective of the present study was to evaluate associations between fiber intake, colonic transit time and stool frequency. Thirty-eight patients aged 4 to 14 years were submitted to alimentary evaluation and to measurement of colonic transit time. The median fiber intake of the total sample was age + 10.3 g/day. Only 18.4% of the subjects presented a daily dietary fiber intake below the levels recommended by the American Health Foundation. In this group, the median left colonic transit time was shorter than in the group with higher dietary fiber intake (11 vs 17 h, P = 0.067). The correlation between stool frequency and colonic transit time was negative and weak for left colon (r = -0.3, P = 0.04), and negative and moderate for rectosigmoid and total colon (r = -0.5, P<0.001 and r = -0.5, P<0.001, respectively). The stool frequency was lower in the group with slow transit time (0.8 vs 2.3 per week, P = 0.014). In conclusion, most patients with chronic functional constipation had adequate dietary fiber intake. The negative correlation between stool frequency and colonic transit time increased progressively from proximal segments to distal segments of the colon. Patients with normal and prolonged colonic transit time differ in terms of stool frequency.