Usability evaluation of collaborative writing system for education usage is very essential to improve its functionality to make it effective, efficient and satisfactory for future use. In this thesis, the usability of web office (ThinkFree doc) i.e. one of collaborative tool was tested using mix research approach. Usability evaluation was done in step by step process, where usability test was conducted using think aloud protocol and observation during testing was noted down. Test results were then analyzed and questionnaire was designed for quantitative survey. Questionnaires were then distributed among those students who have been using Thinkfree doc for educational collaborative work. Interviews were conducted with all selected participants individually for results validations. During usability evaluation process positive and negative effects regarding software‟s usage were noted down. The result revealed that overall system‟s response is very slow. The software needs to improve its processing speed to make it more efficient for future use. The system also needs to improve overall functionality (e.g. collaborative work, synchronization, uploading and track changes etc) to provide accurate and complete results according users‟ requirements. / First Author: M. Afsar Khan. Mohallah madani masjid nawan killi village & P.O Gujar Garhi District Mardan NWFP Pakistan, Second Author: Sher Hassan. Timergara Dir Lower NWFP Pakisan

Inland waters including streams, rivers, reservoirs and lakes are regarded as a significant site of Organic Carbon (OC) cycling, and greenhouse gas production. As a result, there has been significant recent interest in the rates and fate of fluvial carbon exported from organic soils, such as peatlands. Additionally, peatlands can be subject to substantial degradation resulting in high rates of fluvial OC export, and this has led to efforts to repair degraded peatlands through restoration programmes. As a consequence, the study of degraded areas is useful to quantify the upper values of carbon release, understand processes of transformation, and evaluate the success of restoration programmes. Importantly peatlands are also collection areas for drinking water, which has implications for treatment, and requires better understanding of carbon cycling upstream of treatment works, in headwater rivers, reservoirs and pipes. UK upland blanket peat catchments are a key location in which to consider global questions surrounding fluvial carbon export and transformations, as they are highly degraded, provide a source of drinking water supply, and are currently undergoing pioneering methods of landscape scale restoration. This thesis considers Kinder Scout, an area of highly degraded and gullied blanket peatland in the South Pennines, UK. Using analysis of water samples collected over several years in the Kinder reservoir catchment and plateau, this thesis presents three novel contributions to global questions concerning OC cycling and peatlands. Firstly it provides (to date), the only carbon budget for a reservoir in a peat dominated catchment with high Particulate Organic Carbon (POC) export, which demonstrates that reservoirs may be net sources of Dissolved Organic Carbon (DOC), with the implication that POC-DOC interactions are important OC transformation mechanism in degraded systems. Secondly through use of a unique integrated combination of methods, it considers changes in carbon flux and composition in both river, lake and pipe locations, providing detailed understanding of the relative roles of river reaches, reservoirs and supply pipes, in controlling fluvial carbon cycling in peatland systems, and upstream of water treatment works. An important implication here, is that rate and direction of change in water treatability varies through a catchment. Finally, it includes results from the first widespread monitoring of the catchment scale effects of a new method of peatland revegetation. This restoration approach is being applied at landscape scale and the findings here, are that despite fears to the contrary, it does not lead to short term increases in fluvial carbon loss, which is an important piece of evidence supporting practical conservation approaches in these systems. To further enhance this research, a combination of field and laboratory investigations into carbon transformation processes, and ongoing restoration mentoring should be undertaken.

Denitrification removes large amounts of reactive nitrogen (N) from ecosystems via reduction of nitrate to dinitrogen gas. In aquatic ecosystems, the influences of terrestrial and aquatic sources of organic matter (OM) on denitrification are potentially complex. Terrestrially-derived OM is often less labile than autochthonous OM; it may inhibit denitrification directly via biochemical mechanisms; and it may indirectly inhibit denitrification by reducing light availability to—and thus OM exudation by—aquatic primary producers. Using a natural dissolved OM gradient among rivers of northern Florida, I investigated these mechanisms using laboratory denitrification assays subjected to factorial amendments of NO3- and dextrose, humic acid dosing, and cross-incubations of sediments and water. Results indicated that C-limitation increased with DOC concentrations, consistent with the indirect inhibition hypothesis. Blackwater neither depressed nor stimulated denitrification rates, indicating that this DOC neither directly inhibits nor acts as a usable OM source for denitrifiers.

The objective of this thesis was to reconstruct the Sedimentary, Cryostratigraphic and Paleoclimatic history of Two Moose Lake, central Yukon using a new analytical technique for dating ice wedges using Dissolved Organic Carbon (DOC). During two field seasons in August 2013 and April 2014, 442 samples were collected from a newly exposed headwall of a thaw slump with 7 ice wedges and over 4m of sediment. Using cryostratigraphy, granulometry, stable isotopes and 18 14C-DOC ages, 4 stratigraphic units were delineated: 1) a sediment-rich ice layer inferred to be of glacial origin (>32ka BP); 2) a silt-rich layer deposited during the Holocene Thermal Maximum (~10 to 8.2ka BP); 3) a silt with organics layer deposited from ~8ka to 6.4ka BP, and 4) a paleo-active layer and modern active layer. 14C-DOC dating indicated two periods of ice wedge activity at Two Moose Lake, the first during the late Pleistocene (31,608 to 12,990 yr cal BP) and from the mid-Holocene to present (6,328 to 892 yr cal BP). The presence of late-Pleistocene aged ice wedges at Two Moose Lake supports the common belief of an unglaciated central Yukon during the most recent McConnell glaciation from 29.6 to 13ka BP. Values for δ18O from the Holocene- and Pleistocene-aged ice wedges were 2-3‰ and 5-9‰ depleted compared those of modern precipitation from Mayo (-22.32‰). Medium-resolution (2-4cm) sampling along with multiple 14C-DOC samples along a transect allowed for the creation of a continuous δ18O and temperature age profile to be developed from multiple ice wedges, showing a strong consistency between overlapping ages. The reconstruction of the paleoclimate of Two Moose lake is consistent with known events from southern Yukon including the Boutellier Inderstadial, a cold unglaciated central Yukon during the McConnell Glaciation, warming during the Holocene Thermal Maximum (HTM) followed by an extreme cooling event at 8.2ka BP, a cooling event at 4.2ka BP, and the subsequent warming to present temperatures.

Increased DOC and Fe concentrations from terrestrial landscapes has led to the browning of boreal surface waters. The negative societal and ecological impacts of brownification are increased cost of water purification, increased presences of algae and cyanobacteria, loss of ecosystem services and reduced recreational value. Impacts of climate change, changes in land use and reduced sulfur deposition have been identified as drivers of brownification. While it has been recognized that DOC and Fe from terrestrial landscapes is increasing, little has been done to understand the impact of different land use practices on brownification. This research aims at evaluating the DOC and Fe runoff from spruce plantations, clear-cuts and wetland landscapes and determining the export of DOC from these landscapes into humic lakes. To do that, streams running through these three different land use types were sampled for water colour, pH, temperature, conductivity, DOC and Fe both at upstream and downstream of each land use type. Further, water discharge was calculated with the help of flow speed measurements and stream profiling (width, depth and channel shape). DOC (but not Fe) concentrations changed significantly depending on land use type. Wetlands lead to reduced DOC concentrations, whereas especially spruce plantations lead to increased stream water DOC concentrations.

La regulación mundial de emisiones contaminantes en el sector de la automoción está siendo cada día más estricta. La implantación de nuevos procedimientos está presionando la industria hacia la búsqueda de nuevas tecnologías que cumplan los objetivos de reducción de emisiones contaminantes. En el medio plazo se espera que las pruebas de emisiones a baja temperatura ambiente sean obligatorias en el proceso de homologación. La combustión a bajas temperaturas influye de forma importante en la velocidad de la reacción conllevando un aumento de las emisiones y finalmente al apagado de llama. Bajo estas condiciones, se produce un aumento de las emisiones de hidrocarburos (HC) y monóxido de carbono (CO) así como un aumento del consumo de combustible. Además, en condiciones de baja temperatura ambiente las emisiones de óxidos de nitrógeno (NOx) pueden aumentar debido a la desactivación de los sistemas de recirculación de gases de escape. En la presente tesis, se ha analizado el efecto de la baja temperatura ambiente en un motor diesel HSDI. Los ensayos fueron realizados en ciclos de conducción NEDC y WLTC. La influencia directa de las bajas temperaturas en las emisiones se analizó por medio de las medida bruta de contaminantes, aguas arriba de los sistemas de postratamiento. El funcionamiento de los sistemas de postratamiento también fue evaluado a bajas temperaturas mediante la eficiencia de la oxidación catalítica de HC y CO. Los resultados de este estudio mostraron un deterioro de las emisiones y del rendimiento efectivo a bajas temperaturas. El efecto de las bajas temperaturas varió dependiendo de condiciones de carga. El ciclo NEDC se consolida como el peor escenario de conducción, para la realización de pruebas a baja temperatura, con un incremento del 270% en HC, 250% en NOx, 125% en CO y 20% en consumo específico. El mayor grado de carga junto con el carácter más transitorio del ciclo WLTC mostraron un efecto menor de las bajas temperaturas ambiente con un aumento del 150% en HC y 250% en NOx. A diferencia del ciclo NEDC, las emisiones de CO se redujeron en un 20% y no se detectó un aumento del consumo de combustible. Además del aumento de la formación de contaminates, el análisis del catalizador de oxidación mostró una reducción de la eficiencia en ambos ciclos de conducción NEDC y WLTC. El presente trabajo tiene por objetivo comparar dos sistemas de gestión térmica para la mejora del funcionamiento de MCIA a bajas temperaturas. El primer sistema estaba basado en la gestión del flujo de refrigerante para evitar subenfriamiento en condiciones de funcionamiento en frío. Por un lado, se propusieron estrategias de bajo y nulo flujo en el circuito de refrigerante motor. Por otro lado, se realizaron ensayos con 0 flujo en el circuito de refrigerante del WCAC para evitar el subenfriamiento del aire de admisión durante puntos de baja carga en condiciones de funcionamiento en frío. El otro sistema incluía la recuperación de energía térmica del escape (EGHR). El refrigerante del WCAC se empleó como fluido de recuperación conectándose con un intercambiador de escape. La primera parte de los resultados de la gestión térmica están centrados en el análisis individual de los distintos sistemas de gestión. En las conclusiones se comparan todos los sistemas propuestas explicando las diferencias entre ellos. Mediante el uso del EGHR las emisiones de HC fueron reducidas, durante los puntos de baja carga, en comparación con el resto de estrategias térmicas planteadas. El análisis energético del EGHR se centró en la eficiencia y en el estudio la recuperación por cambio de fase. El papel que la entalpia de cambio de fase juega en la recuperación de calor residual fue estudiado por medio de la medición de concentración de vapor de agua en el gas de escape en la entrada y salida del intercambiador del EGHR. La condensación del vapor de agua de escape representó el 25% de toda la / Automotive world-wide pollutant emissions regulations are getting more stringent every day. New testing procedures are pushing the automotive industry towards researching new technologies to accomplish the emissions targets. In the mid-term future is expected that low ambient temperature emissions testing will become mandatory for any engine model type approval. Low ignition temperature greatly influences on combustion rate leading to emissions increase and eventually to misfiring events. In these conditions, high emissions of unburned hydrocarbon (HC) and carbon monoxide (CO) are released along with fuel consumption penalties. In addition, nitrogen oxides (NOx) emissions may rise under cold conditions owing to the disabling of Exhaust Gas Recirculation (EGR) systems at cold conditions. In this thesis the effect of low ambient temperature in a High Speed Direct Injection (HSDI) Light Duty (LD) engine is analysed. Tests were performed in New European Driving Cycles (NEDC) and Worldwide harmonized Light vehicles Tests (WLTC). Direct influence of low temperature on engine emissions was addressed by engine out pollutants sampling. The effect on aftertreatment systems was also evaluated by the CO and HC oxidation efficiency. The results of this survey indicated a general detriment of pollutant emissions and brake thermal efficiency at low ambient temperatures. The effect of low temperature varied depending on the engine load test conditions. NEDC comes up as the worst scenario for low temperature testing with an increase of 270% in HC, 250% in NOx, 125% in CO and 20% in Brake Specific Fuel Consumption (BSFC). Running at higher engine loads and transient conditions, as it's performed in WLTC tests, showed a lower effect of ambient temperature with an increase of 150% in HC and 250% in NOx. In contrast to NEDC, CO emissions were reduced in 20% and no engine efficiency penalty was spotted. In addition to the pollutant emission formation increase, the aftertreatment analysis showed a significant reduction of the Diesel Oxidative Catalyst (DOC) efficiency in both NEDC and WLTC. This work is aimed to analyse and compare two different thermal management approaches for engine enhancement running at low ambient temperature. The first approach relied on coolant management aimed to avoid overcooling when running at cold conditions. On one hand, low flow and 0 flow engine coolant strategies were performed while Water Charge Air Cooled (WCAC) coolant is recirculated. On the other hand, WCAC 0 flow was applied for avoiding overcooling at low ambient temperatures. The other layout was based on an exhaust gas heat recovery system (EGHR). WCAC coolant was directed to an exhaust tail pipe heat exchanger for waste heat recovery. Recovered heat was released in the WCAC for speeding up the intake air temperature increase. The first part of the thermal management results is focused on the analysis by thermal layout. Comparison of both thermal management is discussed in the conclusions section of that chapter. By enabling an EGHR system, HC emissions were reduced during low load driving phases in comparison with the other of layouts. EGHR energy analysis was also conducted, focusing on energy efficiency and phase change recovery analysis. The role that latent enthalpy plays on waste heat recovery was addressed by measuring the water vapour concentration in the exhaust stream at both EGHR heat exchanger inlet and outlet. Water vapour condensation represented the 25% of the total recovered energy. / La regulació mundial d'emissions contaminants en el sector de l'automoció està sent cada vegada més estricta. La implantació de nous procediments està pressionant la indústria cap a la cerca de noves tecnologies que complisquen els objectius de reducció d'emissions contaminants. En el mig termini s'espera que les proves d'emissions a baixa temperatura ambient siguen obligatòries en el procés d'homologació. La combustió a baixes temperatures influeix de forma important en la velocitat de la reacció comportant un augment de les emissions i finalment a l'apagat de flama. Sota aquestes condicions, es produeix un augment de les emissions d'hidrocarburs (HC) i monòxid de carboni (CO) així com un augment del consum de combustible. A més, en condicions de baixa temperatura ambiente les emissions d'òxids de nitrogen (NOx) poden augmentar a causa de la desactivació dels sistemes de recirculació de gasos d'escapament. En la present tesi, s'ha analitzat l'efecte de la baixa temperatura ambiente en un motor dièsel HSDI. Els assajos van ser realitzats en cicles de conducció NEDC i WLTC. La influència directa de les baixes temperatures en les emissions es va analitzar per mitjà de la mesura bruta de contaminants, aigües a dalt dels sistemes de postractament. El funcionament dels sistemes de postractament també va ser avaluat a baixes temperatures mitjançant l'eficiència de la oxidació catalítica de HC i CO. Els resultats d'aquest estudi van mostrar una deterioració de les emissions i del rendiment efectiu a baixes temperatures. L'efecte de les baixes temperatures variava depenent de les condicions de càrrega. El cicle NEDC es consolida com el pitjor escenari de conducció, per a la realització de proves a baixa temperatura, amb un increment del 270% en HC, 250% en NOx, 125% en CO i 20% en consum específic. El major grau de càrrega juntament amb el caràcter més transitori del cicle WLTC van mostrar un efecte menor de les baixes temperatures ambient amb un augment del 150% en HC i 250% en NOx. A diferència del cicle NEDC, les emissions de CO es van reduir en un 20% i no es va detectar un augment del consum de combustible. A més de l'augment de la formació de contaminants, l'anàlisi del catalitzador d' oxidació va mostrar una reducció de l'eficiència en tots dos cicles de conducció NEDC i WLTC. El present treball té per objectiu comparar dos sistemes de gestió tèrmica per a la millora del funcionament dels MCIA a baixes temperatures. El primer sistema estava basat en la gestió del flux de refrigerant per a evitar subrefredament en condicions de funcionament en fred. D'una banda, es van proposar estratègies de baix i nul flux en el circuit de refrigerant motor. D'altra banda, es van realitzar assajos amb 0 flux en el circuit de refrigerant del WCAC per a evitar el subrefredament de l'aire d'admissió durant punts de baixa càrrega en condicions de funcionament en fred. L'altre sistema incloïa la recuperació d'energia tèrmica de l'escapament (EGHR). El refrigerant del WCAC es va emprar com fluït de recuperació connectant-se amb un bescanviador d'escapament. La primera part dels resultats de la gestió tèrmica estan centrats en l'anàlisi individual dels diferents sistemes de gestió. En les conclusions es comparen tots els sistemes proposats explicant les diferències entre ells. Mitjançant l'ús del EGHR les emissions de HC van ser reduïdes, durant els punts de baixa càrrega, en comparació de la resta d'estratègies tèrmiques plantejades. L'anàlisi energètic del EGHR es va centrar en l'eficiència i en l'estudi de la recuperació per canvi de fase. El paper que l'entalpia de canvi de fase juga en la recuperació de calor residual va ser estudiat per mitjà del mesurament de concentració de vapor d'aigua en el gas d'escapament en l'entrada i eixida del bescanviador del EGHR. La condensació del vapor d'aigua de l'escapament va representar el 25% de tota l'energia recuperada. / Moratal Martínez, AA. (2018). EXPERIMENTAL ANALYSIS OF THERMAL MANAGEMENT INFLUENCE ON PERFORMANCE AND EMISSIONS IN DIESEL ENGINES AT LOW AMBIENT TEMPERATURE [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/111950 / TESIS

During recent decades the brownification through leaching of organic carbon into Northern hemisphere water bodies has become apparent. This is considered a problem because of the implications it has on ecosystems and freshwater sources used for drinking water. It could be beneficial if wetlands can be used for reducing brownification but also detrimental if wetlands instead increase it as construction of wetlands is common practice for treating agricultural runoff in Sweden.  This study compares inlet and outlet absorbance in five wetlands in Kalmar County in Sweden and finds that one removes colour, two increases colour and two does not change the colour of the water at all. The study also compares absorbance values with variables concerning flow and temperature and concludes that a higher absorbance at inlet increases removal similar to how nutrient removal in wetlands work. Inlet absorbance is also dependent on flow with higher flow resulting in higher absorbance. Periods of no flow did not contribute to any changes in absorbance, but this could be because of a limited sample pool. Future recommendations for research include a more extensive look into periods of no flow and affecting variables to ensure wetlands do not contribute to brownification.

The Diesel Oxidation Catalyst (DOC) is subjected to harsh conditions, causing its performance to diminish over time as the result of different aging mechanisms, which either decreases or lowers the accessibility to the catalyst’s active sites. Previous work using chemisorption to quantify aging progression has resulted in a reproducibility of 17%. In this study it has been attempted to lower this, while also performing performance evaluations to see if correlations exist between dispersion and Light-Off Temperature (LOT). Two catalysts have been investigated, LLC (Low Loading Catalyst) and HLC (High Loading Catalyst). These were hydrothermally aged at 600 C, 700 C and 800 C. In addition to these, two HLC engine cell samples were also investigated. To ensure sample homogeneity, different sample preparation methods were investigated. Catalyst samples were crushed, or had their washcoat layer removed, or were milled and then sieved. A total of 5 runs were done using fresh catalysts of LLC and HLC to calculate the standard deviation. Evaluation of performance was done on all samples using Synthetic Catalyst Activity Testing (SCAT). It was deemed that the only viable sample preparation method was to mill and sieve as other methods would be hard to reproduce. The results showed that the reproducibility for LLC was %STD = 4% and for HLC %STD = 2%. For LLC, a correlation between catalytic activity and dispersion was found. The activity dropped with respect to the dispersion in a close to linear fashion without a large effect on BET surface area. For HLC the dispersion decreased largely upon hydrothermal aging, however no correlation was found with the activity; only when aged at 800 C a significant change in LOT was noted. The BET surface area measurements were inconsistent. Lower dispersion sometimes resulted in higher surface area. Engine cell samples exhibited notable decrease in dispersion, but not in surface area, and did not correlate to the hydrothermally aged catalysts, which might be due to other effects inhibiting CO chemisorption during measurements. / Dieseloxidationskatalysatorn (DOC) utsätts för tuffa förhållanden, vilket medför att dess prestanda minskar med tiden på grund av olika åldringsmekanismer, vilka antingen minskar dess aktiva säten eller minskar tillgängligheten till dessa. Tidigare studier då kemisorption använts för att kvantifiera vilken utsträckning katalysatorn har blivit deaktiverad har resulterat i en reproducerbarhet på 17%. Denna studie har syftat till att minska detta, men även till att utföra prestandamätningar för att se om det existerar korrelationer mellan dispersion och tändtemperatur (LOT). Två katalysatorer undersöktes, LLC (lågladdad katalysator) och HLC (högladdad katalysator), både som färska, men även som hydrotermiskt åldrade i 600 C, 700 C and 800 C. Dessutom undersöktes två motorcellsprover av HLC. För att säkerställa provhomogenitet undersöktes olika provprepareringsmetoder. Katalysatorprover krossades, eller fick washcoat avlägsnat eller maldes samt siktades. Totalt fem körningar gjordes på färska katalysatorer (LLC och HLC). Prestandamätningar gjordes på samtliga prov i Synthetic Catalyst Activity Testing (SCAT). Det bedömdes att den enda gångbara provprepareringsmetoden var att mala samt sikta katalysatorn då de andra metoderna skulle bli svåra att upprepa på ett reproducerbart sätt. Resultaten visade att reproducerbarheten för LLC var %STD = 4% och för HLC %STD = 2%. LLC visade på korrelation mellan katalytisk aktivitet och dispersion. Aktiviteten minskade linjärt utan större förluster i BETytarea. För HLC minskade dispersionen i hög grad med ökad åldringstemperatur, däremot kunde ingen korrelation med katalytisk aktivitet påvisas; enbart då katalysatorn åldrades vid 800 C ändrades LOT signifikant. Förändringarna i BET-ytarean var inte beroende av åldringstemperatur då lägre dispersion ibland resulterade i högre ytarea. För motorcellsproverna uppmättes en märkbart låg dispersion, medan ytarean var relativt oförändrad. Dessa resultat kunde inte korreleras till de hydrotermiskt åldrade proverna, vilket kan bero på att andra effekter inhiberat CO kemisorptionen.

In natural ecosystems, like deciduous and coniferous forests, soil CO2 flux or soil respiration is highly variable and influenced by multiple factors including temperature, precipitation, dissolved soil organic carbon (DOC), dissolved organic matter (DOM), and bacterial and fungal biomass and diversity. However, as the human population continues to grow rapidly, so too do urbanized landscapes with unknown consequences to soil respiration. To determine the extent urbanization influences seasonal shifts in microorganisms and environmental drivers alter soil respiration, we evaluated bacterial and fungal communities, soil physiochemical characteristics, and respiration in forested and urbanizing ecosystems in three watersheds across northern Utah, USA. Based on the next-generation sequencing of the 16s DNA and RNA, we found that montane bacteria were predominantly structured by season while urban bacteria were influenced by degree of urbanization. There was no apparent effect of season on montane fungi, but urban fungal communities followed patterns similar to urban bacterial communities. Bacterial diversity was sensitive to seasonality, especially in montane ecosystems, declining 21-34% from spring to summer and staying relatively low into fall, and fungal diversity was generally depressed in spring. Urban bacterial communities were differentiated by substantially more bacterial taxa with 62 unique OTUs within families structing phylogenetic differences compared with only 18 taxa differentiating montane communities. Similar to bacteria and fungi, DOC and ammonium concentrations fluctuated predominantly by season while these same parameters where highly variable among urban soils among the three watersheds. Structural components of DOM via parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices show varying patterns between montane and urban systems with humic substance resistance to biodegradability found more dominantly in montane systems. Incorporating all soil chemical parameters, daily temperature and moisture, and fungal and bacterial diversity and richness in mixed linear effects models describing daily CO2 over all seasons, we found that a single model best described montane soil respiration, while individual watershed models best described urban respiration. Montane respiration was related to the availability of DOC, different DOM components, and rRNA-based bacterial diversity . Alternatively, urban respiration was influenced by either bacterial diversity and richness in our rapidly urbanizing environment, DOM characteristics and soil O2 in the more agricultural urban soils, or the DOM parameter humification index (HIX) in highly urbanized soils. Our results suggest that urbanization creates distinct bacterial and fungal communities with a single soil biotic or chemical parameter structuring soil respiration, while montane ecosystems select for similar bacterial and fungal communities with respiration sensitive to fluctuations in soil moisture, bacteria and the recalcitrance of carbon (C) resources.

No description available.