Nutrient runoff from excess land application of poultry litter in the Chesapeake Bay Watershed has caused damage to the Chesapeake Bay and lead to the need for alternative poultry litter disposal methods. This study provided an economic feasibility analysis of the use of poultry litter as a partial replacement of coal at an electrical generating unit in Virginia's Chesapeake Bay Watershed. Previous research on the feasibility of converting litter to energy failed to include uncertainty in benefit-cost variables, therefore, this study used risk analysis to incorporate variable uncertainty. Project net worth in previous studies was measured under a public investment scenario with risk neutral preferences but did not take into account risk averse preferences common in private investment. This paper compared benefits under both public risk neutral and private risk averse investor preferences. NPV results showed the proposed project to be feasible but sensitive to the acquisition cost of poultry litter, the unit ash value of litter, and future coal price projections. The maximum level of risk aversion required for feasibility increased when expected returns were measured on an investment scale compared to an annual income scale. Poultry litter combustion produced lower levels of NOx and SO₂ emissions compared to coal, therefore, emission allowance trading through the EPA market based trading programs generated additional benefits to the model and increased the maximum level of risk aversion permitted for feasibility. Results suggested the potential to dispose of 110 thousand tons of poultry litter per year from the Chesapeake Bay Watershed without violating EPA emission standards. / Master of Science

This is a bachelor thesis project covering a method to get an insight to what could be a first step in the electrification of the aviation system in Sweden. Sweden currently has 39 active commercial airports and the goal is to integrate airports capable of supporting electric airplanes into this system. By utilizing available travel-data, a program is created to optimally select the number of airports to electrify and which ones. No definite answer is decided however it is shown that either 3, 7 or 13 airports are good choices. Which number is favored is dependent on what aspect is weighted more: emission reduction or cost.

During the last two centuries, the development of the internal combustion engine has followed the evolution of the customer expectations. From the race for pure performances, high power, and fun to drive, perfectly well illustrated by the fabulous Mercedes 300 SL, the focus moved towards fuel efficient engines under the pressure of the still increasing oil prices. The well-known Diesel powertrain, up to this period limited to industrial vehicles, suddenly became the object of many researches, even for automotive manufacturers, specialists for sport cars. Technologic developments, mainly concerning turbocharging and injection, allowed the opening of the passenger cars market to CI engines due to acceptable noise, power and still unreachable efficiency. On the gasoline side, direct injection moved from racing to economic cars by the introduction of the stratified combustion. More recently, the pressure rose for dramatically reducing the air pollution, both in urban areas, by limiting NOx and soot, but also, at the scale of the earth, for managing CO2 rejections and thereby enlarging the efforts on efficiency. The two first combustion systems described in this document are concerning spray guided and air guided design alternatives to obtain a fuel stratification, and thereby operate the gasoline engine without throttling the air intake, aiming at a better fuel efficiency. The first concept, called MID3S, was based on a 3 valve combustion chamber with a large squish area and a high compression ratio over 12; inspired from the May Fireball system, it was developed with a house made high pressure injector operating up to 80 bars with an outwardly opening needle. An ultra-lean flame-able mixture was formed at WOT in the vicinity of the spark plug for different operating points as low as idle, while the maximum performances were quite close to the targeted 37 kW/l. The efficiency was significantly improved compared to a similar MPI engine while CO and HC were quite acceptable. On the contrary, NOx and soot would have to be improved. The robustness of the squish aerodynamic motion was unfortunately balanced by the sensitivity of spray angle and penetration versus the back pressure and thereby late injection timings, creating plug wetting and fouling. The hollow cone structure of the fuel plume was clearly responsible of this behavior, especially because of the effect of the air entrainment inside the spray. An increase of the injection pressure from 30 to 80 bar, and probably upper, would probably reduce this effect. Concerning methodologies, a dedicated cylinder head was designed with two endoscope locations in order to visualize the interaction between spray, air, walls and combustion –or more precisely soot- with a high speed camera operating within visible wavelengths. The spray structure, formed by a succession of ligaments at the surface of the plume, was clearly emphasized in atmospheric conditions. The second design, called K5M, was based on an adjustable high tumble motion generated in the intake port. A swirl injector provided by Siemens and located between the two intake valves of the pent roof chamber, was operated until 80 bar. Mixture preparation was relying on the interaction between the air motion and the spray, the tumble velocity deviating fuel droplets towards the spark plug situated at the center of the chamber. 3D CFD simulation, PIV and LIF visualization techniques on an optical single cylinder engine were used in parallel in order to understand the spatial evolution of the equivalence ratio during the cycle and the ability to operate the engine at WOT, even at part load. At low BMEP and speed, the natural reduction of the tumble intensity might have been followed by a significant reduction of the injection pressure in order to secure an accurate balance between the two momentum energies; unfortunately, both high cycle to cycle aerodynamic fluctuations and a poor spray atomization at 30 bar didn’t allow to achieve an acceptable ignition stability at low loads due to a too lean mixture in the plug vicinity. Protruded electrodes could have been a solution to the problem but their reliable use in serial life was not secured. On the contrary, mid load performances were globally adequate. The third concept is concerning Diesel combustion aiming at very low NOx and soot emissions by using an innovative injection system. The basic idea relies on the use of a quite homogeneous combustion at low load –called Mild HCCI- and on a diffusion controlled one at higher loads. Based on two injections close one of the other in the vicinity of TDC, the Mild HCCI allows to moderate the combustion noise inherent to the premixed burning phase as the fuel injected during the second injection cools down the first combustion; the advantages of very low NOx and soot emissions until around 8 bar BMEP are meanwhile maintained. Above this value, the noise level becomes unacceptable for automotive applications and the come back to a conventional diffusive combustion becomes mandatory. Based on early academic investigations pointing out the positive effect of small nozzle holes associated to high injection pressures in terms of soot via a significant difference between the lift-off length and the liquid penetration length, an innovative injection system was adapted to a conventional combustion chamber. The first conclusion was concerning a significant improvement of the NOx/soot tradeoff at mid and high loads with quite usual EGR rates. This advantage was due to a much better fuel atomization linked to both small holes and high pressures. The second conclusion was related to the possibility to achieve a “0 soot/ 0 NOx” combustion at high loads while very much increasing EGR and air mass flows. In this case, a Lifted Flame Diffusion Controlled combustion was generated, confirming on a scale 1 engine the results obtained in academic conditions. Nevertheless, the use of 3D simulation allowed to demonstrate that mixture preparation was only one part of the result; the location of the different stages of the combustion in a Kamimoto diagram, much away from the NOx and soot peninsula, highlighted the impact of the LTC (Low Temperature Combustion) thermodynamics. Unfortunately, despite these good results, industrially available EGR and air systems are not able to provide the necessary mass flows. Concerning tools, the development steps were followed by intensive spray visualizations for both the liquid and the vapor phases, in conditions closer and closer to the actual engine. These measurements allowed to precisely evaluate the impact of the diameter size, the rail pressure and the oxygen content on the difference between lift-off and liquid lengths. Finally, the importance of coupling investigation tools like visualization and 3D simulation in conditions as close as possible to the actual engine in terms of temperature, pressure and timing –eg the ability to record a complete mixture and combustion cycle- has been emphasized for both future SI and Diesel engines. In particular, the forecasted increase of the rail pressures will lead to re-optimize the different available spray models and eventually to re-adapt them in terms of physical phenomena because of the great variations of the spray velocity and of the Weber number. The presence of cavitation in the nozzle holes will also have to be taken into account as it has a key role versus coking. In conclusion, it is quite clear that the development of stratified gasoline and low emissions Diesel engines will more and more rely on the mixture preparation and on its association with low gas temperatures. / Gastaldi, P. (2015). INFLUENCE OF THE MIXTURE PREPARATION ON THE COMBUSTION IN DIRECT INJECTION ENGINES [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48534

Tesis por compendio / [EN] Climate change, a resultant effect of greenhouse gas emissions, is a worldwide concern because its continuation is having significant impacts on people, natural resources and economic conditions around the world. The root cause of this recent past and projected climate change is now recognised to be the warming potential of a number of greenhouse gases that, by absorbing terrestrial infrared radiation, raise the temperature of the troposphere and with it, global surface temperatures. The major greenhouse gases are water vapour, carbon dioxide, methane, nitrous oxide and fluorinated gases. While carbon dioxide receives the most attention as a factor which causes global warming, methane also cause significant radiative forcing. Methane is only second to carbon dioxide in its contribution to global warming and its emissions are caused by both natural and anthropogenic actions. Human activities such as intensive livestock farming are the primary cause of the increased methane concentrations in the atmosphere, being ruminants the animals which create large amounts of methane via fermentation of feeds in the rumen. During this physiological digestive process, hydrogen is released by some microbes during fermentation of forage and is used by methanogenic Archaea (methanogens) to convert carbon dioxide to methane, which is released through eructation, normal respiration and small quantities as flatus. Rumen fermentation of cattle contributes the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. Several techniques have been developed to quantify methane emissions from ruminants - indirect calorimetry, sulphur hexafluoride tracer technique and in vitro gas production technique - and some strategies for reduction of methane emissions from the rumen have been described - defaunation treatment, vaccine and dietary composition -. The initial topics of this research were: design the experiments with goats because there are not many reports about methane emissions in these animals; investigate the influence of dietary composition (carbohydrates) as a strategy for reduction methane emissions from the rumen; and use the indirect calorimetry as method to quantify methane production. Consequently, three experiments were performed. Murciano-Granadina goats during mid or late lactation were used. Diets were mixed rations that differed in the inclusion of cereal or fibrous by-products. The effect of diet was studied on milk yield, digestibility, rumen parameters, energy partitioning, carbon and nitrogen balance, substrate oxidation and methane productions. In the first experiment, gas exchange was measured using a face mask which was fixed to the head of the goat by a rubber band; a sample of exhaled gas was stored in a gas collection bag which was connected to an analyzer, and it measured the concentration of O2, CO2 and CH4 from the air. This first experiment replaces corn grain with beet pulp and the amount of methane recovered was 19.6 and 29.7 g/day, respectively. In the other two experiments, gas exchange was measured by a head box designed for small ruminants where the goat introduced the whole head and a specific software automatically recorded concentrations of O2, CO2 and CH4 from the exhaled air continuously throughout the day. The second experiment involved two diets with high and low level of starch and no differences were found on methane emission (28.5 g/day). The experiment number three replaces ingredient by ingredient like in the experiment number one. Here, barley grain was replaced with orange pulp or soybean hulls and no differences were found, with an average methane production value of 41 g/day. The metabolizable energy intake during the three experiments was 1279 kJ/kg of BW0.75 and day on average, and the efficiency use of metabolizable energy intake for milk production was 0.6. / [ES] El cambio climático es una preocupación de ámbito mundial debido a que su perpetuación en el tiempo está teniendo un impacto significativo sobre las personas, los recursos naturales y las condiciones económicas de todo el mundo. La causa fundamental de este fenómeno es el potencial de calentamiento de una serie de gases de efecto invernadero que, mediante la absorción de la radiación infrarroja terrestre, elevan la temperatura de la troposfera y, con ella, las temperaturas superficiales de la Tierra. Los principales gases de efecto invernadero son el vapor de agua, el dióxido de carbono, el metano, el óxido nitroso y los gases fluorados. El metano, después del dióxido de carbono, es el gas que más repercusión tiene sobre el calentamiento global y sus emisiones son causadas tanto por acciones naturales como humanas. Actividades antropogénicas tales como la ganadería intensiva son la principal causa de aumento de las concentraciones de metano en la atmósfera, siendo los rumiantes los animales que mayores cantidades de metano generan a través de la fermentación de alimentos que se produce en el rumen. Las emisiones de metano del ganado vacuno son las que principalmente contribuyen al efecto invernadero seguido de las ovejas, las cabras y los búfalos, respectivamente. Se han descrito diferentes técnicas para medir las emisiones de metano de los rumiantes - la calorimetría indirecta, la técnica del marcador con hexafluoruro de azufre y la técnica de producción de gas in vitro - y, además, se han mencionado algunas estrategias para reducir las emisiones de metano - la defaunación, las vacunas y la composición de la dieta -. Los puntos clave de esta Tesis fueron: diseñar los experimentos con cabras, debido a que no hay muchas investigaciones sobre emisiones de metano en estos animales; estudiar la influencia de la composición de la dieta (hidratos de carbono) como una posible estrategia para la reducción de las emisiones de metano del rumen; y utilizar la calorimetría indirecta como método para cuantificar la producción de metano. Se realizaron tres experimentos. Se utilizaron cabras de la raza Murciano-Granadina en mitad o final de la lactación. Las dietas eran raciones mixtas que diferían en la inclusión de cereal o subproductos fibrosos. El efecto de la dieta se estudió en la producción de leche, la digestibilidad, los parámetros del rumen, la partición de energía, el balance de carbono y nitrógeno, la oxidación de nutrientes y las producciones de metano. En el primer experimento, el intercambio de gases se midió utilizando una mascarilla que se fijó a la cabeza de la cabra con una goma; se almacenó una muestra de gas exhalado en una bolsa de recogida de gas que estaba conectada a un analizador, y se midió la concentración de O2, CO2 y CH4 del aire. En este primer experimento se reemplazó el grano de maíz con pulpa de remolacha y la cantidad de metano recuperado fue del 19,6 y 29,7 g/día, respectivamente. En los otros dos experimentos, el intercambio de gases se midió mediante una urna o cajón diseñado para pequeños rumiantes, donde la cabra introducía toda la cabeza y un programa informático grababa automáticamente las concentraciones de O2, CO2 y CH4 del aire exhalado de forma continua a lo largo del día. El segundo experimento consistió en dos dietas con alto y bajo nivel de almidón y no se encontraron diferencias en la emisión de metano (28,5 g/día). En el tercer experimento se sustituyó ingrediente por ingrediente como en el experimento número uno. El grano de cebada se sustituyó por pulpa de naranja o cascarilla de soja y tampoco se encontraron diferencias, con un valor promedio de la producción de metano de 41 g/día. La energía metabolizable ingerida durante los tres experimentos fue de 1279 kJ/kg de peso metabólico (PV0.75) y día de promedio, y la eficiencia de utilización de la energía metabolizable ingerida para la producción de leche fue de / [CA] El canvi climàtic és una preocupació d'àmbit mundial ja que la seua perpetuació en el temps està tenint un impacte significatiu sobre les persones, els recursos naturals i les condicions econòmiques de tot el món. La causa fonamental d'aquest fenòmen és el potencial d'escalfament d'una sèrie de gasos d'efecte hivernacle que, mitjançant l'absorció de la radiació infraroja terrestre, eleven la temperatura de la troposfera i, amb ella, les temperatures superficials de la Terra. Els principals gasos d'efecte hivernacle són el vapor d'aigua, el diòxid de carboni, el metà, l'òxid nitrós i els gasos fluorats. El metà, després del diòxid de carboni, és el gas que més repercussió té sobre l'escalfament global i les seues emissions són causades tant per accions naturals com humanes. Activitats antropogèniques com ara la ramaderia intensiva són la principal causa d'augment de les concentracions de metà a l'atmosfera, sent els remugants els animals que més quantitats de metà generen a través de la fermentació d'aliments que es produeix al rumen. Les emissions de metà dels bovins són les que principalment contribueixen a l'efecte hivernacle seguit de les ovelles, les cabres i els búfals, respectivament. S'han descrit diferents tècniques per mesurar les emissions de metà dels remugants - la calorimetria indirecta, la tècnica del marcador amb hexafluorur de sofre i la tècnica de producció de gas in vitro - i, a més, s'han esmentat algunes estratègies per reduir les emissions de metà - la defaunació, les vacunes i la composició de la dieta -. Els punts clau d'aquesta Tesi van ser: dissenyar els experiments amb cabres, pel fet que no hi ha moltes investigacions sobre emissions de metà en aquests animals; estudiar la influència de la composició de la dieta (hidrats de carboni) com una possible estratègia per a la reducció de les emissions de metà del rumen; i utilitzar la calorimetria indirecta com a mètode per quantificar la producció de metà. Es van realitzar tres experiments. S'utilitzaren cabres de la raça Murciano-Granadina a la meitat o final de la lactació. Les dietes eren racions mixtes que diferien en la inclusió de cereal o subproductes fibrosos. L'efecte de la dieta es va estudiar en la producció de llet, la digestibilitat, els paràmetres del rumen, la partició d'energia, el balanç de carboni i nitrogen, l'oxidació de nutrients i les produccions de metà. En el primer experiment, l'intercanvi de gasos es va mesurar utilitzant una màscara que es va fixar al cap de la cabra amb una goma; es va emmagatzemar una mostra de gas exhalat en una bossa de recollida de gas que estava connectada a un analitzador, i es va mesurar la concentració d'O2, CO2 i CH4 de l'aire. En aquest primer experiment es va reemplaçar el gra de blat de moro amb polpa de remolatxa i la quantitat de metà recuperat va ser del 19,6 i 29,7 g/dia, respectivament. En els altres dos experiments, l'intercanvi de gasos es va mesurar mitjançant una urna o calaix dissenyat per a petits remugants, on la cabra introduïa tot el cap i un programa informàtic gravava automàticament les concentracions d'O2, CO2 i CH4 de l'aire exhalat de forma contínua al llarg del dia. El segon experiment va consistir en dues dietes amb alt i baix nivell de midó i no es van trobar diferències en l'emissió de metà (28,5 g/dia). En el tercer experiment es va substituir ingredient per ingredient com en l'experiment número u. El gra d'ordi es va substituir per polpa de taronja o pellofa de soja i tampoc es van trobar diferències, amb un valor mitjà de la producció de metà de 41 g/dia. L'energia metabolitzable ingerida durant els tres experiments va ser de 1279 kJ/kg de pes metabòlic (PV0.75) i dia de mitjana, i l'eficiència d'utilització de l'energia metabolitzable ingerida per a la producció de llet va ser de 0,6. / Ibáñez Sanchis, C. (2015). INFLUENCE OF NUTRITION ON METHANE GAS PRODUCTION IN MURCIANO-GRANADINA GOATS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59389 / Compendio

The objectives of this study were to determine: 1) ammonia emission rates from stored scraped and flushed manure from dairy cows fed either normal or low N diet; and 2) seasonal effects on ammonia emission rates from stored scraped and flushed dairy manure. Four pilot-scale tanks were used for manure storage with different treatments - scraped manure for normal diet (NS), flushed manure for normal diet (NF), scraped manure for low N diet (LS), and flushed manure for low N diet (LF). The first part of the study lasted for 1 month and four treatments were all investigated; the second part of the study lasted for 12 months and two tanks with treatments NS and NF were investigated. Dynamic flux chambers and a photoacoustic gas analyzer were used to measure ammonia emission rates. There was no significant change of the N content of manure as the dietary N content is reduced (from 17.8% to 15.9% crude protein). However, ammonia emission rates from manure storage tanks were reduced by 33% (from 27.4 ± 38.1 to 18.4 ± 21.9 mg m⁻²h⁻¹; P<0.0001 based on paired t-test). Flushing manure reduced emission rates by 72% compared to scraping manure (from 35.6 ± 39.6 to 10.1 ± 8.2 mg m⁻²h⁻¹; P<0.0001 based on paired t-test). Ammonia emission rates for NS, NF, LS and LF were 43.9 ± 48.0, 10.9 ± 8.7, 27.4 ± 27.3, and 9.3 ± 7.8 mg m-2 h-1, respectively. The chamber headspace temperature for NS, NF, LS and LF were 26.0 ± 6.9, 25.8 ± 6.8, 26.6 ± 6.5, and 27.2 ± 6.7 °C, respectively. The manure pH for NS, NF, LS, and LF were 6.3 ± 0.1, 6.4 ± 0.3, 6.4 ± 0.1, and 6.1 ± 0.1, respectively. Both dietary N reduction and manure flushing are recommended to reduce ammonia emission rates from dairy manure storage tanks. Ammonia emission rates were higher in summer and fall, due to higher air temperature and higher manure pH. The pH of scraped manure was 7.2 ± 0.6, 6.7 ± 0.2, 6.5 ± 0.3 and 7.0 ± 0.3 for fall, winter, spring and summer, respectively. The pH of flushed manure was 6.8 ± 0.4, 6.7 ± 0.4, 6.4 ± 0.3 and 6.8 ± 0.4 for fall, winter, spring and summer, respectively. Ammonia emission rates from scraped manure for fall, winter, spring, and summer were 7.4 ± 8.6, -0.5 ± 1.2, 1.1 ± 1.9, and 5.8 ± 2.7 mg m⁻²h⁻¹, respectively. Ammonia emission rates from flushed manure for fall, winter, spring, and summer were 3.9 ± 4.2, -0.5 ± 0.9, 0.8 ± 1.4, and 4.4 ± 1.2 mg m⁻²h⁻¹, respectively. Seasonal changes of air temperature and manure pH were key factors affecting ammonia emissions from manure storage in this study. Seasonal climate conditions including precipitations (rainstorms and snows) and icing can cause reduction of ammonia emissions from manure storage in open air. More attention should be paid to reduce ammonia emissions in warmer seasons, e.g., by covering the storage facilities. / Master of Science

A comprehensive model is developed to estimate and predict the fuel consumption and emissions by domestic commercial aviation in the Continental United States. Most of the existing fuel consumption and emission models are limited in their ability to predict the annual fuel burn for air transportation at the national level. For example, those models either require real track data or are developed only to model single flight scenarios.  The model developed in this thesis is part of a software framework called the Transportation Systems Analysis Model (TSAM). The model has the capability to estimate fuel consumption and emissions for millions of domestic flights in a year in the continental U.S. TSAM is a nationwide, long-distance, multimodal travel demand forecast model developed at Virginia Tech. The model enables TSAM to quantify fuel and emission metrics for various modes of transportation. The EUROCONTROL Base of Aircraft Data (BADA) is employed as the Aircraft Performance Model to simulate individual flight profiles and calculate fuel burn rates. Fuel consumption on the ground (taxi mode) is estimated separately. Different operational conditions like wind states, terminal area detour, cruise altitude and airport elevation are considered in the model. Emissions of HC, CO, NOx and SOx are computed inside the Landing/Take-off (LTO) cycle based on the fuel consumption estimate, while greenhouse gas of CO2 is calculated for the complete flight cycle. / Master of Science

Broilers are raised indoors on high density farms with bedding/litter to trap their manure. Ammonia gas, which is produced as the manure decomposes, has adverse effects on human health, bird welfare and the environment. Using litter amendments can reduce the amount and, consequently, the effects of ammonia emitted from broiler houses. The objective of this study was to determine the effectiveness of a biodegradable litter amendment (BLA) in reducing ammonia emitted from a broiler house. A pilot scale test was set up with six adjacent, individually ventilated rooms and a stocking density of 0.07 m² per bird. The birds were fed with a standard commercial, corn and soybean meal based diet and water was provided ad libitum. The first flock was grown on 10 cm of fresh, kiln-dried pine shavings, while subsequent flocks were grown on top-dressed reused litter. The two treatments (control (CTL) and BLA) were randomly assigned to the six rooms after flock 1, to give three replicates per treatment. The exhaust air from the rooms was sampled for ammonia concentration for two days each week starting at four days of age to determine the amount of ammonia emitted. Over three subsequent flocks, the total mass of ammonia emitted from rooms treated with BLA was 31% to 47% lower than the control. Ammonia emitted per bird grown on treated litter and per kg of harvested bird weight was 32% to 44% lower, and the exhaust fans ran 7% to 22% less than CTL over the same period. For both BLA and CTL, the amount of ammonia emitted generally increased with bird age and litter reuse. The study showed that BLA effectively reduced ammonia emitted from a broiler house and that there are potential energy savings from using the amendment. However, ammonia emitted from the BLA rooms during the final flock was 57% higher than CTL, which was attributed to insufficient water (less than 18% moisture by weight) to support the reaction between BLA and ammonia. / Ph. D.

An experimental investigation of highly underexpanded exhaust jets impinging in a direction normal to a curved surface was conducted in the NASA-Langley Research Center 55-foot vacuum cylinder. The investigation included measurements of impingement pressures and measurements of various normal shock characteristics. Variables of the investigation were the size of the jet, jet-exit Mach number, exhaust gas, distance of the jet from the impingement surface, curvature of the surface, and jet-exit to ambient pressure ratio. The experimental data are presented and compared with available theory. / Master of Science

Formaldehyde emissions from non-structural wood composites are regulated and the regulation target is urea-formaldehyde (UF) resin. UF resins are hydrolytically unstable and constantly emit formaldehyde as a function of temperature and relative humidity. When heated, wood also generates formaldehyde, but this was of little concern until 2010 when formaldehyde regulations became much more demanding. This regulation motivated the industry to account for all formaldehyde sources, synthetic as from resin, and biogenic as from wood. This effort represents first steps towards quantifying biogenic and synthetic contributions to formaldehyde emissions in non-structural wood composites. It is possible to distinguish the 13C/12C isotope ratio of UF resins from the isotope ratio of plant biomass. Conditions during and after composite hot-pressing promote reactions that generate formaldehyde from wood and UF resin, and the kinetic isotope effect continuously lowers the product isotope ratios as a function of yield. If such isotope fractionation did not occur, it would be a simple matter to quantify contributions of wood and UF resin to formaldehyde emissions using static isotope ratios. Isotope fractionation, therefore, complicates the requirements for distinguishing biogenic and synthetic formaldehyde in wood composite emissions. Those requirements are 1) establish the reference carbon isotope ratios in wood and in UF resin (just the formaldehyde portion of UF), and 2) estimate the kinetic isotope effects in formaldehyde generation by wood and cured UF resin. The latter requirement fixes a range for the respective isotope ratios; the numerical ranges enable a simple model of the average isotope ratio for a mixture of biogenic and synthetic formaldehyde in wood composite emissions. Finally, the measured isotope ratio of captured emissions would be compared to the model. This work did not achieve all aspects of the requirements mentioned, but a solid foundation was established for future completion of the ultimate goals. In reference to requirement 1, the carbon isotope ratio of experimental Pinus taeda wood was accurately measured (including some isolated fractions) using isotope ratio mass spectroscopy (IRMS). IRMS of UF resin first requires removal of urea carbons- UF resin was subjected to acid hydrolysis and capture of the resin formaldehyde into aqueous ammonium hydroxide. This provided a nearly quantitative conversion (negligible isotope fractionation) of resin formaldehyde into hexamine for IRMS. Using this hexamine method, the formaldehyde carbon isotope ratios of two industrial UF resins were accurately measured, demonstrating basic feasibility for the project goal. Estimating the kinetic isotope effect (Requirement 2) required creation of a thermochemical reactor, where wood or cured UF resin was heated under N2 flow such that the emitted formaldehyde was easily captured. In this case, conversion of captured formaldehyde into hexamine was abandoned in favor of silica gel cartridges loaded with sodium bisulfite. Isolation and IRMS of the formaldehyde-bisulfite adduct were effective and considered easily transferable to industrial settings. This system was employed to measure fractionation in cured resin as a function of relative humidity, and in Pinus taeda wood as a function of relative humidity, temperature, and time. More information about isotope fractionation is required; but most notable was the fractionation behavior in wood where evidence was found for multiple formaldehyde generating reactions. Overall, this work established feasibility for the goals and laid the foundation for future efforts. / Master of Science / Home-interior products like cabinetry are often produced with wood composites adhesively bonded with urea-formaldehyde (UF) resin. UF resins are low cost and highly effective, but their chemical nature results in formaldehyde emission from the composite. High emissions are avoided, and the federal government has regulated and steadily reduced allowable emissions since 1985. The industry continuously improved UF technologies to meet regulations, as in 2010 when the most demanding regulations were implemented. At that time, many people were unaware that wood also generates formaldehyde; this occurs at very low levels but heating during composite manufacture causes a temporary burst of natural formaldehyde. Some wood types produce unusually high formaldehyde levels, making regulation compliance more difficult. This situation, and the desire to raise public awareness, created a major industrial goal: determine how much formaldehyde emission originates from the resin and how much originates from the wood. These formaldehyde sources can be distinguished by measuring the carbon isotope ratio, 13C/12C. This ratio changes and varies due to the kinetic isotope effect. Slight differences in 13C and 12C reactivity reveal the source as either petrochemical (synthetic formaldehyde) or plant-based (biogenic formaldehyde). This work demonstrates that achieving the industry goal is entirely feasible, and it provides the analytical foundation. The technical strategy is: 1) establish reference isotope ratios in wood and in UF resin, and 2) from the corresponding wood composite, capture formaldehyde emissions, measure the isotope ratio, and simply calculate the percentage contributions from the reference sources. However, a complication exists. When the reference sources generate formaldehyde, the respective isotope ratios change systematically in a process called isotope fractionation (another term for the kinetic isotope effect). Consequently, this effort developed methods to measure fractionation when cured UF resin and wood separately generate formaldehyde, with greater emphasis on wood. Isotope fractionation in wood revealed multiple fractionation mechanisms. This complexity presents intriguing possibilities for new perspectives on formaldehyde emission from wood and cured UF resin. In summary, this work demonstrated how source contributions to formaldehyde emissions can be determined; it established effective methods required to refine and perfect the approach, and it revealed that isotope fractionation could serve as an entirely novel tool in the materials science of wood composites.

In conjunction with Atlantic Pacific Engineering and the Henry County Public Service Authority, Virginia Tech’s Environmental Engineering program measured the emissions from an experimental scrap tire incinerator/wastewater treatment plant sludge dryer. This report recounts the techniques used and the results obtained during this testing. The Virginia Department of Environmental Quality supplied a list of pollutants of permitting interest which included a variety of criteria pollutants, toxics, and metals. Sampling for all the listed compounds required adherence to EPA Methods 5, 201A, 29, 0010, 0011, 0030, 6, 7D, 26A, and 18. Emissions testing transpired during the incinerator’s 72-hour test burn: 0800 October 30th to 0800 November 2nd, 1995. Due to time constraints, only part of one nonpotable water sampling series was completed rather than the proposed duplicate testing using both drying agents: nonpotable water and sludge. High particulate (57 lb/hr) and metal (21.4 lb/hr total) emissions indicate a fairly significant amount of air pollution control equipment will be necessary for a commercial plant. Both nitrogen oxides and sulfur dioxide had low emission rates: 1.73 lb/hr and 0.64 lb/hr, respectively, due to the nonpotable water spray acting as a fairly efficient scrubber removing a great deal of nitrogen oxides, sulfur dioxide, and some metals. Because of sample analysis preparation problems, no organics results were obtained. Commercial development of this incinerator will have to include a sizable quantity of air pollution control equipment: a $5 million plant will need approximately $1 million worth of control equipment. / Master of Science