Indoor air quality at a waste incineration plant in Finland

Waste has been incinerated for energy utilization for more than a hundred years, but the harmful emissions emitted from the incineration plants did not begin to cause concern until the 1980s. Many plants were shutdown and the waste incineration plant in Kyläsaari Helsinki was one of them. In later years, new landfill regulations have increased the interest in waste incineration. During the last year, four new plants were taken into operation in Finland, Westenergy in Vaasa among them. The presence of dust has been observed indoors at Westenergy waste incineration plant. Dust is defined as particles with a diameter above 10 μm, while fine particles have a diameter smaller than 2.5 μm, ultrafine under 0.1 μm and nanoparticles under 0.05 μm. In recent years, the focus of particle health research has been changed to investigate smaller particles. Ultrafine particles have been found to be more detrimental to health than larger particles. Limit values regulating the concentrations of ultrafine particles have not been determined yet. The objective of this thesis was to investigate dust and particles present inside the Westenergy waste incineration facility. The task was to investigate the potential pollutant sources and to give recommendations of how to minimize the presence of dust and particles in the power plant. The total particle number concentrations and size distributions where measured at 15 points inside the plant with an Engine Exhaust Particle Sizer (EEPS) Spectrometer. The measured particles were mainly in the ultrafine size range. Dust was only visually investigated, since the main purpose was to follow the dust accumulation. The measurement points inside the incineration plant were chosen according to investigate exposure to visitors and workers. At some points probable leakage of emissions were investigated. The measurements were carried out during approximately one month in March–April 2013. The results of the measurements showed that elevated levels of dust and particles are present in the indoor air at the waste incineration plant. The cleanest air was found in the control room, warehouse and office. The most polluted air was near the sources that were investigated due to possible leakage and in the bottom ash hall. However, the concentrations were near measured background concentrations in European cities and no leakage could be detected. The high concentrations were assumed to be a result of a lot of dust and particles present on surfaces that had not been cleaned in a while. The main source of the dust and particles present inside the waste incineration plant was thought to be particles and dust from the outside air. Other activities in the area around the waste incineration facility are ground work activities, stone crushing and traffic, which probably are sources of particle formation. Filtration of the outside air prior entering the facility would probably save personnel and visitors from nuisance and save in cleaning and maintenance costs.

[Air de Laodice]

Soitinnus: lauluääni (sopraano), piano.

Very High Energy Gamma-Rays emitting BL LAC's Population Study

Context: BL Lacs are the most numerous extragalactic objects which are detected in Very High Energy (VHE) gamma-rays band. They are a subclass of blazars. Large flux variability amplitude, sometimes happens in very short time scale, is a common characteristic of them. Significant optical polarization is another main characteristics of BL Lacs. BL Lacs' spectra have a continuous and featureless Spectral Energy Distribution (SED) which have two peaks. Among 1442 BL Lacs in the Roma-BZB catalogue, only 51 are detected in VHE gamma-rays band. BL Lacs are most numerous (more than 50% of 514 objects) objects among the sources that are detected above 10 GeV by FERMI-LAT. Therefore, many BL Lacs are expected to be discovered in VHE gamma-rays band. However, due to the limitation on current and near future technology of Imaging Air Cherenkov Telescope, astronomers are forced to predict whether an object emits VHE gamma-rays or not. Some VHE gamma-ray prediction methods are already introduced but still are not confirmed. Cross band correlations are the building blocks of introducing VHE gamma-rays prediction method. Aims: We will attempt to investigate cross band correlations between flux energy density, luminosity and spectral index of the sample. Also, we will check whether recently discovered MAGIC J2001+435 is a typical BL Lac. Methods: We select a sample of 42 TeV BL Lacs and collect 20 of their properties within five energy bands from literature and Tuorla blazar monitoring program database. All of the data are synchronized to be comparable to each other. Finally, we choose 55 pair of datasets for cross band correlations finding and investigating whether there is any correlation between each pair. For MAGIC J2001+435 we analyze the publicly available SWIFT-XRT data, and use the still unpublished VHE gamma-rays data from MAGIC collaboration. The results are compared to the other sources of the sample. Results: Low state luminosity of multiple detected VHE gamma-rays is strongly correlated luminosities in all other bands. However, the high state does not show such strong correlations. VHE gamma-rays single detected sources have similar behaviour to the low state of multiple detected ones. Finally, MAGIC J2001+435 is a typical TeV BL Lac. However, for some of the properties this source is located at the edge of the whole sample (e.g. in terms of X-rays flux). Keywords: BL Lac(s), Population study, Correlations finding, Multi wavelengths analysis, VHE gamma-rays, gamma-rays, X-rays, Optical, Radio

Development and characterization of thin printed films for gas sensing applications

The monitoring and control of hydrogen sulfide (H2S) level is of great interest for a wide range of application areas including food quality control, defense and antiterrorist applications and air quality monitoring e.g. in mines. H2S is a very poisonous and flammable gas. Exposure to low concentrations of H2S can result in eye irritation, a sore throat and cough, shortness of breath, and fluid retention in the lungs. These symptoms usually disappear in a few weeks. Long-term, low-level exposure may result in fatigue, loss of appetite, headache, irritability, poor memory, and dizziness. Higher concentrations of 700 - 800 ppm tend to be fatal. H2S has a characteristic smell of rotten egg. However, because of temporary paralysis of olfactory nerves, the smelling capability at concentrations higher than 100 ppm is severely compromised. In addition, volatile H2S is one of the main products during the spoilage of poultry meat in anaerobic conditions. Currently, no commercial H2S sensor is available which can operate under anaerobic conditions and can be easily integrated in the food packaging. This thesis presents a step-wise progress in the development of printed H2S gas sensors. Efforts were made in the formulation, characterization and optimization of functional printable inks and coating pastes based on composites of a polymer and a metal salt as well as a composite of a metal salt and an organic acid. Different processing techniques including inkjet printing, flexographic printing, screen printing and spray coating were utilized in the fabrication of H2S sensors. The dispersions were characterized by measuring turbidity, surface tension, viscosity and particle size. The sensing films were characterized using X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and an electrical multimeter. Thin and thick printed or coated films were developed for gas sensing applications with the aim of monitoring the H2S concentrations in real life applications. Initially, a H2S gas sensor based on a composite of polyaniline and metal salt was developed. Both aqueous and solvent-based dispersions were developed and characterized. These dispersions were then utilized in the fabrication of roll-to-roll printed H2S gas sensors. However, the humidity background, long term instability and comparatively lower detection limit made these sensors less favourable for real practical applications. To overcome these problems, copper acetate based sensors were developed for H2S gas sensing. Stable inks with excellent printability were developed by tuning the surface tension, viscosity and particle size. This enabled the formation of inkjet-printed high quality copper acetate films with excellent sensitivity towards H2S. Furthermore, these sensors showed negligible humidity effects and improved selectivity, response time, lower limit of detection and coefficient of variation. The lower limit of detection of copper acetate based sensors was further improved to sub-ppm level by incorporation of catalytic gold nano-particles and subsequent plasma treatment of the sensing film. These sensors were further integrated in an inexpensive wirelessly readable RLC-circuit (where R is resistor, L is inductor and C is capacitor). The performance of these sensors towards biogenic H2S produced during the spoilage of poultry meat in the modified atmosphere package was also demonstrated in this thesis. This serves as a proof of concept that these sensors can be utilized in real life applications.

Characterization of amine-based CO2 adsorbent for Direct Air Capture

Direct air capture technologies extract CO2 from air at a concentration of as low as 400ppm. The captured CO2 can be used for the production of synthetic methane or liquid fuels. In the literature survey of this thesis, results related to direct air capture by using solid sorbents are presented and critically discussed. In the experimental part, a proprietary amine functionalized resin is characterized for direct air capture. Structural comparison is also made to a commercial resin of similar type. Based on the literature survey, the most important parameters in direct air capture process are low adsorption and desorption temperatures, good cyclic stability in dry and humid conditions, high CO2 outlet purity and a high working capacity. Primary amine functionalized solid sorbents are found to often have good qualities for direct air capture, but overall process performance is rarely studied exhaustively. Based on FTIR spectra, both resin adsorbents are found to be consisted of polystyrene functionalized with primary amine, and capture CO2 by forming carbamate. The commercial resin is more porous, has a slightly higher particle size and contains fewer impurities. Important physical parameters are gained of the proprietary resin, such as internal porosity and median particle size. The resin’s amine group is found to endure thermal treatment reasonably well. CO2 adsorption capacity gained by thermal gravimetry from 400ppm CO2 is highest at 25oC, and is found to be reasonable compared to values presented in literature. Thus, the resin is stated to exhibit promising qualities for direct air capture.

Air-Sea Battle -konsepti John Wardenin Enemy as a System -teorian näkökulmasta

Tutkielman tavoitteena oli analysoida Air-Sea Battle -konseptia ja sen lähtökohtana ollutta viholliskuvaa John Wardenin Enemy as a System -teorian näkökulmasta julkisten asiakirjojen, raporttien ja artikkeleiden avulla. Tutkimusmenetelmänä on käytetty teoriaohjaavaa sisällönanalyysia. Tutkimusongelmaksi muodostui: ”Miten Air-Sea Battle -konsepti näyttäytyy Wardenin Enemy as a System -teorian näkökulmasta?” Tutkimuskysymyksien avulla pyrittiin lisäksi löytämään konseptin kehittämiseen johtaneita tekijöitä suurstrategisella tasolla, arvioimaan konseptin mukaista aseellisen voiman käyttöä sekä analysoimaan konseptia suhteessa Wardenin näkemyksiin sotilasstrategiasta. Wardenin Enemy as a System -teoria on esitelty tutkielman alkupuolella hyödyntäen alkuperäistekstejä, aiheesta kirjoitettuja tutkimuksia ja artikkeleita sekä sotataidollista kirjallisuutta. Air-Sea Battle -konseptia käsittelevän luvun aineisto on luokiteltu Wardenin neljän strategisen kysymyksen teemojen, eli tavoitteen, vaikuttamisen kohteiden, keinojen ja irtautumisen, mukaisesti. Tärkeimmät lähteet varsinaisen Air-Sea Battle -asiakirjan lisäksi olivat Yhdysvaltojen turvallisuus- ja sotilasstrategiaa määrittelevät dokumentit, tutkimuslaitosten julkaisemat raportit sekä aikakauslehtiartikkelit. Aineiston perusteella Yhdysvallat näkee tiettyjen valtioiden, kuten Kiinan, kehittyvät niin kutsutut anti-access/area denial -suorituskyvyt uhkana alueelliselle tasapainolle ja heidän kyvylleen ylläpitää sotilaallista läsnäoloa strategisesti merkittävillä alueilla. Air-Sea le -konseptin tavoitteena on määritellä ja kehittää suorituskyvyt, operatiiviset suunnitelmat ja toimintamallit, joiden mukaan toimivalla joukolla kyetään luomaan riittävä pelotevaikutus konfliktin ehkäisemiseksi tai säilyttämään toiminnanvapaus alueella sen muodostuessa.

Air defence in Northern Europe

Finnish Defence Studies is published under the auspices of the National Defence College, and the contributions reflect the fields of research and teaching of the College. Finnish Defence Studies will occasionally feature documentation on Finnish Security Policy. Views expressed are those of the authors and do not necessarily imply endorsement by the National Defence College.

Natural freeze crystallization : purification of aqueous Na2SO4 solutions with cold air

The aim of this thesis was to examine efficiency of freeze crystallization and eutectic freeze crystallization in purification of wastewater by imitating natural freezing. In addition, a mathematic model based on heat transfer to determine ice thickness and ice growth rate was examined. Also, the amount of sodium sulfate crystallized at the eutectic point was under investigation. In literature part, advantages and applications of the freeze crystallization are discussed, and possibility to apply it in Northern hemisphere winter weather conditions is under study. Furthermore, main sources of sodium sulfate from Finnish industries are described. The experiments were carried out in modified chest freezer, where a fan was placed in order to obtain laminar air flow inside. Picolog PT-104 data logger was used to monitor temperature changes in the salt-water solution, and constant temperature was maintained in the crystallizer with Lauda RP 850 thermostat. The impurity of formed ice layer was determined by weighing ice samples after experiment and again after 24 hours drying to full dryness in oven. Volume of salt-water solution was also measured after experiment. The highest purity of formed ice layer was obtained with small temperature difference and with long freezing time. On the other hand, the amount of crystallized sodium sulfate was its greatest with long freezing time and higher temperature difference. The results obtained by the mathematic model and empirical results did not differ significantly in most of the experiments. However, the difference increased when salt-water mixture reached its eutectic point, leading to simultaneous ice and salt crystallization. Eutectic point was reached only with the highest salt concentration with one exception. In these cases, calculated values were in many cases greater than the experimental ones. In winter weather conditions freeze crystallization is cost-effective wastewater treatment method and rather simple. Nonetheless, the efficiency and separation rate are strongly depended on ambient temperature and its changes