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Gints Kucinskis, Gunars Bajars, Janis Kleperis and Janis Smits

Kinetic Behavior of LiFePO4/C Thin Film Cathode Material for Lithium-Ion Batteries

LiFePO4 was prepared in a solid state synthesis with various levels of carbon content. LiFePO4/C thin films were obtained via magnetron sputtering. The surface morphology and structure was examined. Electrochemical properties of LiFePO4/C were studied, by using cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. Thin films acquired show a potential use as a cathode in lithium ion batteries, displaying charge capacity up to 34 mAh g-1.

Open access

Jānis Kleperis, Biruta Sloka, Justs Dimants, Ilze Dimanta and Jānis Kleperis

Abstract

The analysis of the results of long-term air quality monitoring in Riga is presented, which shows that in city centre throughout the measurement time (2004-2014) according to the guidelines defined by the European Union directives and Latvian laws the limits of small particles PM10 and nitrogen dioxide (NO2) are exceeded. From the nature of appearance of pollution and from the research of morphology and composition of fine dust particles it was concluded that in the city centre where the monitoring was performed the main air pollutants are caused by internal combustion engine vehicles. The measures to reduce air pollution performed by two Action Programs (2004-2009; 2011-2015) of the City Council showed that there were only two possible ways to improve air quality in urban environment ‒ to decrease the number of traffic units and/or to decrease exhaust emissions from vehicles.

From the analysis of energy consumption and resources used for it the conclusion was drawn that Latvia is dependent on fossil fuel import, especially in traffic sector (99 %). A new trend has been observed in Latvia ‒ the type of cars is changing: the number of gasoline cars rapidly decreases and number of diesel cars is growing. Both fuels in exhaust gases of second-hand cars are giving high emissions of fine particles (soot) and nitrogen oxides as compared with new cars; 72 % of cars on the roads of Latvia are more than 13 years old. The switch to bio-diesel can improve Latvian statistics according to CO2 reduction target for 2020 but not the concentration of PM10 and NO2 on streets with dense traffic.

Therefore, to improve air quality in urban environment and simultaneously reduce the dependence of Latvia from fossil fuel import, a scenario is proposed for the changeover to zero-carbon technologies in transport and energy production. Hydrogen is analyzed from the point of view of availability of resources and commercialized technologies. The research of the public opinion was done because there is little awareness in society about hydrogen as energy carrier and simultaneously as fuel.

Open access

Janis Kleperis, Gunars Bajars, Ingrida Bremere, Martins Menniks, Arturs Viksna, Agnese Osite and Dmitrijs Pavlicuks

Air Quality in Riga and Its Improvement Options

Air quality in the city of Riga is evaluated from direct monitoring results and from accounting registered air pollutants in the city. It is concluded that from all air polluting substances listed in the European Commission directives, only nitrogen dioxide NO2 and particulate matter PM10 exceed the limits. In assessing the projected measures to improve air quality in Riga, it can be concluded that the implementation of cleaner fuels and improvements in energy efficiency of household and industrial sectors will decrease particle pollution, but measures in the transport sector will also contribute to reducing air pollution from nitrogen oxides.

Open access

Immanuels Taivans, Normunds Jurka, Līga Balode, Māris Bukovskis, Uldis Kopeika, Vadims Ogorodniks, Jānis Kleperis, Gunta Strazda, Viesturs Šiliņš and Agris Martinsons

Exhaled Air Analysis in Patients with Different Lung Diseases Using Artificial Odour Sensors

Sniffing breath to diagnose a disease has been practiced by doctors since ancient times. Nowadays, electronic noses are successfully used in the food, textile and perfume industry as well as for air pollution control. The aim of this study was to test whether exhaled breath analysed by an artificial nose could identify and discriminate between different lung diseases. A total of 76 individuals were tested: 25 bronchial asthma, 19 lung cancer, 10 pneumonia, 6 chronic obstructive pulmonary disease (COPD) patients and 16 healthy volunteers. Exhaled air was collected in plastic bags and immediately analysed using an electronic nose instrument (9185, Nordic Sensors AB) containing 14 different odour sensors. Multifactor logistic regression analysis was used to determine correlation between the amplitudes of sensor responses and the clinical diagnoses of patients and to calculate sensitivity and specificity of the method for each diagnosis. For diagnostics of asthma the sensitivity was found to be 84% and specificity — 86%. For lung cancer, the sensitivity was 74% and specificity, 95%; for pneumonia 90% and 98%, but for COPD, 33% and 97%, respectively. We conclude that an artificial nose is able to discriminate among different lung diseases with sufficiently good accuracy. This method may be further developed to implement it in clinical medicine for express diagnostics of acute and chronic lung diseases.