The co-firing technology of coal with biomass has been implemented to enhance the usage of biomass in power generation, thus reducing the release of greenhouse gas emissions. This study deals with the fireside issues, namely ash-related issues that arise during co-combustion of coal and biomass takes place. Ash release from biomass can lead to ash deposition problems such as fouling and slagging on surfacesof power generation boilers. The scope of this work includes the development of a conceptual model that predicts the ash release behaviour and chemical composition of inorganics in coal and biomass when combusted. An advanced analytical method was developed and introduced in this work to determine the speciation of biomass.The method known as pH extraction analysis was used to determine the inorganic speciation in three biomass samples, namely wood chips, wood bark and straw. The speciation of biomass and coal was used as an input to the model to predict the behaviour and release of ash. It was found that the main gas phases during the combustion of biomass are KCl, NaCl, K2SO4 and Na2SO4. Gas-to-particle formation calculations were carried out to determine the chemical composition of coal andbiomass when cooling takes place in the boiler. The results obtained in this work can be used in future work to determine the ash deposition of coal and biomass in boilers.

<p>Atmospheric particles are ubiquitous in the Earth’s atmosphere and have potential to influence atmospheric chemistry, visibility, global climate and human health, particularly downwind from major pollution sources. The main objective of this thesis was to investigate questions pertaining to the microphysical, chemical and optical properties of aerosol particles by using in situ data collected during four experiments carried out in different regions of the Northern Hemisphere.</p><p>The first two papers of this thesis reports on airborne measurements of the aerosol optical properties performed over the North Atlantic and the Los Angeles basin. Airmasses from Europe and North Africa are usually advected in over the North Atlantic, alternating with the background marine conditions. The results showed that the aerosols are not uniformly distributed in the area and variability in the aerosol fields occurs at sub-synoptic scales. It was also observed that the single scattering coefficient varied as the polluted plumes aged, suggesting a relationship between this quantity and transport time. The measurements performed around the Los Angeles basin showed that the area’s complex topography and local meteorological circulations exert a strong control on the distribution of the aerosol in the basin. Large spatio-temporal gradients in the aerosol optical properties were observed along a transect flown from the shore towards the mountains. Profiles flown over sites located on the mountains displayed a stratified configuration with elevated aerosol layers.</p><p>Airborne data of residual particles collected in orographic wave clouds over Scandinavia were analyzed using a single particle analysis technique. Mineral dust, organic aerosols and sea salt were the main group of particles identified. Residuals composed predominantly of mineral dust were found in glaciated clouds while organic residuals were found in liquid clouds. The results suggest that organic material may inhibit freezing and have considerable influence on supercooled clouds that form through heterogeneous pathways.</p><p>The partitioning of the aerosol particles between cloud droplets and interstitial air has been addressed in terms of their microphysical properties using data obtained at a mountain-top site in Sweden during a stratocumulus event. The results showed that the scavenging efficiency varied during the cloud event, and Aitken-mode particles were also efficiently scavenged in addition to accumulation-mode particles. It is hypothesized that alterations of the aerosol chemical composition occurred during the measurement period, modifying the hygroscopic nature of the particles and decreasing their activation diameter.</p>

Atmospheric particles are ubiquitous in the Earth’s atmosphere and have potential to influence atmospheric chemistry, visibility, global climate and human health, particularly downwind from major pollution sources. The main objective of this thesis was to investigate questions pertaining to the microphysical, chemical and optical properties of aerosol particles by using in situ data collected during four experiments carried out in different regions of the Northern Hemisphere. The first two papers of this thesis reports on airborne measurements of the aerosol optical properties performed over the North Atlantic and the Los Angeles basin. Airmasses from Europe and North Africa are usually advected in over the North Atlantic, alternating with the background marine conditions. The results showed that the aerosols are not uniformly distributed in the area and variability in the aerosol fields occurs at sub-synoptic scales. It was also observed that the single scattering coefficient varied as the polluted plumes aged, suggesting a relationship between this quantity and transport time. The measurements performed around the Los Angeles basin showed that the area’s complex topography and local meteorological circulations exert a strong control on the distribution of the aerosol in the basin. Large spatio-temporal gradients in the aerosol optical properties were observed along a transect flown from the shore towards the mountains. Profiles flown over sites located on the mountains displayed a stratified configuration with elevated aerosol layers. Airborne data of residual particles collected in orographic wave clouds over Scandinavia were analyzed using a single particle analysis technique. Mineral dust, organic aerosols and sea salt were the main group of particles identified. Residuals composed predominantly of mineral dust were found in glaciated clouds while organic residuals were found in liquid clouds. The results suggest that organic material may inhibit freezing and have considerable influence on supercooled clouds that form through heterogeneous pathways. The partitioning of the aerosol particles between cloud droplets and interstitial air has been addressed in terms of their microphysical properties using data obtained at a mountain-top site in Sweden during a stratocumulus event. The results showed that the scavenging efficiency varied during the cloud event, and Aitken-mode particles were also efficiently scavenged in addition to accumulation-mode particles. It is hypothesized that alterations of the aerosol chemical composition occurred during the measurement period, modifying the hygroscopic nature of the particles and decreasing their activation diameter.

The root epidermis, being the outermost cell layer of the organ, is in contact with the soil environment. The position of the epidermis determines its important roles, such as taking up water and ions from the surrounding soil, and defending against harmful microorganisms. What is the chemical composition of the walls in this layer? The chemical nature of the soybean epidermal wall modifying substance was investigated in this study with the use of histochemical tests coupled with electron microscopy, and chemical depolymerizations in combination with chromatography. Soybean (<em>Glycine max</em>) was used as a test species in the present studay. Results of histochemical and electron microscopical studies indicated that the epidermal walls are modified with suberin. The suberized epidermal walls were permeable to apoplastic tracers, differing from those of cells with suberized Casparian bands, possibly due to the spatial distribution or chemical components of the suberin. Suberin may occur in a diffuse form linked with other wall components in the epidermis. What is the chemical nature of this modification, and does it play a role in pathogen resistance? The root epidermal wall compositions of two soybean cultivars were compared; one (cv. Conrad) is resistant to <em>Phytophthora sojae</em> and the other (cv. OX 760-6) is susceptible to this root-rot oomycete. Their epidermal walls were isolated enzymatically and subjected to two different degradation methods, i. e. BF₃-MeOH transesterification and nitrobenzene oxidation. The compositions of depolymerisates of the cell walls determined by GC-MS indicated four dominant suberin monomers varying in chain length from C16 to C24. In all epidermal cell walls, &omega;-hydroxycarboxylic acids were more abundant than diacids, carboxylic acids and alcohols. Two of the monomers detected (hydroxycarboxylic acid and a,&omega;-dicarboxylic acid) are known to be characteristic suberin markers. The quantitative chemical compositions significantly differed in the epidermal cell walls of the two soybean varieties. Walls of the resistant cultivar (Conrad) had a greater quantity of both the aliphatic and aromatic components of the polymer than the susceptible cultivar (OX760-6), providing evidence to support the hypothesis that preformed suberin plays a role in plant defense.

Since the phase stability region of CuInSe2 (CIS) extends as wide as a few atomic percent, composition variation in a microscopic scale is nature to this material and can be detected by EPMA or TEM-EDS. As the detection volume is kept as small as possible (e.g. we used an electron probe with a diameter of 3nm to measure a TEM specimen thinned by a focused ion beam to a 80 nm thickness), the composition data fluctuate rather significantly. For a near-stoichiometric CIS film prepared by co-evaporation or a selenized film using binary selenides as precursor, the composition variations in a nanometer scale were quite distinct. Due to the tedious procedures for making TEM specimens and doing measurements, we normally used EPMA for the composition analysis. Although the composition was measured in a micrometer scale, its variation still can be detected and expressed by the standard deviation. Our results showed that the selenized films prepared by using binary selenides as precursors (they were used to make the device in this work) had much better composition uniformity as compared with the films selenized from the elemental precursors. We also found that even the time period for the selenization process was short (rapid thermal selenization) or long (conventional selenization), the composition variation did not make any changes. Since there still has problems for making devices by using rapid thermal selenization, we successfully fabricated the CIS thin-film solar cells through the conventional selenization processes. The I-V characteristics of the best CIS cell is in the following: Voc=0.398 V, Jsc=41.14 mA/cm2, fill factor (FF)=54.58%, efficiency= 9.29%. We also made a CIGS cell and found that the open circuit voltage was increased to 0.461 V. However, the efficiency was 4.42%. It still needs more effort to boost its short circuit current and fill factor.

A series of laboratory and field investigations were carried out to elucidate the importance of natural organic matter in aquatic systems, i.e., trace element scavenging (e.g., 234Th) by exopolymeric substances (EPS), formation of biofilms, as well as interactions with 129I. A method involving cross flow ultrafiltration, followed by a three-step cartridge soaking and stirred-cell diafiltration, was developed for isolating EPS from phytoplankton cultures, especially in seawater media. EPS isolated from a marine diatom, Amphora sp. was then subjected to semi-quantitative (e.g., carbohydrate, proteins) and quantitative analysis (e.g., neutral sugars, acidic sugars, sulfate). It appeared that Th (IV) binding by EPS was dominated by the acidic polysaccharides of fraction. For EPS of biofilms collected from polluted streams, hydrophobic proteins were the most abundant components in EPS, followed by more hydrophilic carbohydrates. However, chemical composition of carbohydrates or proteins, i.e., monosaccharides and amino acids, respectively, varied with environmental conditions and substrata applied, which suggests that the formation of biofilms on different substrates is regulated by specific properties of microorganisms, environmental conditions and nature of substratum. No correlation between relative hydrophobicity of substratum and development of biofilm was found in this study. A sensitive and rapid GC-MS method was developed to enable the determination of isotopic ratios (129I/127I) of speciated iodine in natural waters. At the F-area of the Savannah River Site (SRS), iodine species in the groundwater consisted of 48.8 percent iodide, 27.3 percent iodate and 23.9 percent organo-iodine. Each of these iodine species exhibited vastly different transport behavior in the column experiments using surface soil from the SRS. Results demonstrated that mobility of iodine species depended greatly on the iodine concentration, mostly due to the limited sorptive capacity for anions of the soil. EPS, especially enzymes (e.g., haloperoxidases) could facilitate the incorporation of iodide to natural organic carbon. At high input concentrations of iodate (78.7 μM), iodate was found to be completely reduced and subsequently followed the transport behavior of iodide. The marked reduction of iodate was probably associated with natural organic carbon and facilitated by bacteria, besides inorganic reductants (e.g., Fe2 ) in sediments and pore water.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2009. / Härtill 5 uppsatser.

Asphalt mixtures or asphalt concrete are used to pave about 93% of about 2.6 million miles paved roads and highways in the US. Asphalt concrete is a composite of aggregates and asphalt binder; asphalt binder works as a glue to bind the aggregate particles. The mechanical response of the asphalt binder is dependent on the time/rate of loading, temperature and age. An asphalt concrete mixture inherits most of these characteristics from the asphalt binder. Also the asphalt binder plays a critical role in providing the asphalt concrete the ability to resist tensile stresses and relaxing thermally induced stresses that can lead to fatigue and low temperature cracking, respectively. Hence, it is very important (but not sufficient) to ensure that asphalt binders used in the production of asphalt concrete are inherently resistant to cracking, rutting and other distresses that a pavement may undergo. Current binder specification (AASHTO M-320) to evaluate its fatigue cracking is based on the stiffness of the binder and not on its tensile strength. Also, measurements following current specifications are made on test specimens subjected to a uniaxial mode of loading that does not produce the same stress state in the binder as in the case of asphalt concrete. Another challenge in being able to produce binders with inherently superior performing characteristics is the fact that the asphalt binders produced in a refinery do not have a consistent chemical composition. The chemical composition of asphalt binder depends on the source and refining process of crude oil. There is a need to better quantify the tensile strength of asphalt binder and understand the relationship between the chemical composition of asphalt binders and its mechanical properties. The knowledge from this study can be used to engineer asphalt binders that have superior performance characteristics. The objective of this research was to quantify the tensile strength of asphalt binder, develop a metric for the tensile strength and identify the relationship between chemical composition and mechanical properties of asphalt binder. Laboratory tests were performed on binders of different grades using a poker chip geometry to simulate confined state by varying the film thickness, rate of loading and modes of loading. The chemical properties of asphalt binder were studied based on SARA fractionation. The findings from this research showed that the modified correspondence principles can unify and explain the rate and mode dependency of asphalt binder. This study also quantified the relationship between chemical composition, and rheological and mechanical properties of asphalt binder. Finally, a composite model was developed based on the individual properties of chemical fractions which could predict the dynamic modulus of the asphaltenes doped and resins doped binder. / text

A study was conducted to evaluate the quality characteristics in a comparative manner of grass-fed and grain-fed beef. Thirty two commercially bred beef steers were used. These steers were assigned to one of four treatments; grain-fed, grass/grain-fed, grass-fed and irrigated. These treatments were each reflective of the ration that would be provided to the animal. Individual animal weights were recorded every 28 days throughout the portion of the study. The grain-fed animals realized the highest (P<0.05) average daily gain with the grass-fed and irrigated having the lowest. The steers were harvested when they reached the pre-determined criteria, which was 0.4 inch back fat as measured at the 12th rib via ultrasonography, for the grain-fed or 800 pounds for the grass-fed animals. All animals, once harvested, were graded based upon USDA quality grades with results mirroring those previously mentioned. Carcasses were involved in an aging study in which all left sides of the carcasses were fabricated into primal cuts, vacuumed packaged and aged for 14 days while the right sides were dry aged during the same period. Shear force data were collected to provide for a measure of tenderness. All samples were significantly (P<0.05) more tender following aging with no difference being realized between aging techniques. Percent cutout was also calculated for the two techniques to quantify what difference, if any, existed. No significant difference (P>0.05) was shown between wet and dry aging with regard to percent cutout. Sensory evaluation was also conducted based upon the attributes of juiciness, tenderness and flavor intensity. For all three attributes grain-fed beef was favored (P<0.05). The panelists detected no difference in aging technique for any of the treatments (P>0.05).Carcass soft tissue chemical composition (lipid, protein and moisture) was also evaluated for the treatments. Grain-fed beef was shown to be highest (P<0.05) for overall percent lipid and lowest for percent moisture and protein. The grass-fed carcasses were the opposite, being highest for overall moisture and protein and lowest for lipid (P<0.05).

There is the first time when there have been compared an activity of enzymes such as α- and β-amylase, maltase, xylanase, cellulase, catalase and protease, the quantity of vitamins C and E and alterable and inalterable amino acids and the value of energy of separate wheat grain cultivars 'Širvinta 1' and 'Zentos' grown up following separate technologies and thereafter sprouted. Germinated wheat grain have been used for producing new fermented milk products when biochemical composition and microbiological pollution have been in-vestigated. / Pirmą kartą buvo nustatytas ir palygintas pagal skirtingas technologijas išaugintų, o po to daigintų kviečių veislių 'Širvinta 1' ir 'Zentos' grūdų α- ir β-amilazių, maltazės, ksilanazės, celiulazės, katalazės, proteazių fermentų aktyvumas, C ir E vitaminų, pakeičiamųjų ir nepakeičiamųjų aminorūgščių kiekiai ir energinė vertė. Pirmą kartą įvertinus ekologiškai augintų, daigintų kviečių biocheminę sudėtį, mikromicetinę ir bakterinę taršą, jie panaudoti naujiems rauginto pieno produktams kurti.