Tesi: "Carbon dioxide enrichment"

1

Dion, Louis-Martin. "Biomass gasification for carbon dioxide enrichment in greenhouses." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103689.

Testo completo

Abstract (sommario):

Biomass heating is used more and more by the greenhouse industry to reduce costs and the environmental footprint of production. The objective of this research project was to investigate the possibility of using the carbon dioxide (CO2) from the exhaust gas of a biomass heating system to enrich greenhouses with CO2 and improve crop yield. When compared to direct combustion, biomass gasification technology offers better control, which helps in reducing atmospheric emissions. Gasification is a thermo-chemical reaction, which converts solid biomass into a gaseous fuel, known as syngas. Experiments were performed at McGill University (Montreal, QC, Canada) using a downdraft gasifier to monitor its performance, with sawdust wood pellets as feedstock. Temperature and pressure monitoring provided valuable insights on optimal gasification temperatures, biomass fuel depletion in the reactor, ash grate shaking requirements, micro-explosions detection, char bed packing and pressure drop across the packed bed filter. The gasifier operated with an average equivalence ratio (the actual air to fuel ratio relative to the stoichiometric air to fuel requirement) of 0.17, below the optimal value of 0.25, and achieved a cold gas efficiency of 59%. Syngas combustion emissions produced an average of 8.8 ppm of carbon monoxide (CO), with 60% of the trials below the ASHRAE standards for indoor air quality and 90% below 20 ppm. The sulphur dioxide (SO2) emissions were below ppm levels, while ethylene (C2H4) emissions were below the critical concentration of 50 ppb for CO2 enrichment. The average nitrogen oxides (NOx) emissions were 23.6 ppm and would need to be reduced to allow commercial operations. From the empirical data, the gasifier operating with sawdust wood pellets, with a consumption of 7.7 kg/hr, could provide a maximum of 22.9 kW of thermal energy and could enrich a maximum of 1540 m2 of greenhouse surface area. Results indicated that biomass, following combustion or gasification, could provide more CO2 for greenhouse enrichment than propane or natural gas per unit of energy. Biomass gasification coupled with syngas combustion could be a promising renewable alternative to propane and natural gas for CO2 enrichment in greenhouses. Le chauffage à la biomasse résiduelle est utilisé de plus en plus par l'industrie serricole afin de réduire les coûts d'opérations et les impacts environnementaux. L'objectif de cette recherche était d'examiner la possibilité d'utiliser le dioxyde de carbone (CO2) des gaz d'échappement d'un système de chauffage à la biomasse afin d'enrichir les serres en CO2 et favoriser le rendement des cultures. Par rapport à la combustion directe, la gazéification de la biomasse offrent un meilleur contrôle qui permet de réduire les émissions atmosphériques. La gazéification est une réaction thermochimique qui convertit la biomasse solide en un combustible gazeux, le syngas. Des expériences ont été réalisées à l'Université McGill (Montréal, QC, Canada) pour étudier les performances d'un gazogène à courant descendant, alimenté avec des granules de sciure de bois. Les données de température et de pression ont fourni des informations sur les températures de gazéification optimale, le niveau de combustible dans le réacteur, les besoins d'agitation de la grille de cendre, la détection de micro-explosions et les chutes de pression au travers du lit de charbon du réacteur et du filtre au charbon. Le gazogène a fonctionné avec un ratio d'équivalence (i.e. le ratio réel par rapport au ratio stoichiométrique d'air et de combustible) moyen de 0.17, inférieur à la valeur optimale de 0.25, et une efficacité de 59%. La combustion du syngas a produit une moyenne de 8.8 ppm de monoxyde de carbone (CO), où 60% des essais ont respecté les normes de qualité de l'air, et 90% ont été en dessous de 20 ppm. Le dioxyde de soufre (SO2) a été indétectable à une résolution en ppm, et les émissions d'éthylène (C2H4) ont été inférieures à la concentration critique de 50 ppb pour l'enrichissement au CO2. La moyenne d'oxydes d'azote (NOx) a été de 23.6 ppm et devrait être réduite pour des opérations commerciales. Le gazogène alimenté aux granules de bois, avec une consommation de 7.7 kg/hr, pourrait fournir 22.9 kW d'énergie thermique et enrichir une serre d'une surface de 1540 m2. Les résultats indiquent que la gazéification de biomasse, couplée à la combustion de syngas, est une alternative prometteuse au propane et au gaz naturel pour l'enrichissement des serres au CO2, puisque davantage de CO2 par unité d'énergie est fournie et ce, à partir d'un combustible renouvelable.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Ghannoum, Oula, of Western Sydney Hawkesbury University, Faculty of Agriculture and Horticulture, and School of Horticulture. "Responses of C3 and C4 Panicum grasses to CO2 enrichment." THESIS_FAH_HOR_Ghannoum_O.xml, 1997. http://handle.uws.edu.au:8081/1959.7/139.

Testo completo

Abstract (sommario):

This project aims at investigating the effect of CO2 enrichment on the growth and gas exchange of C3, C3-C4 and C4 Panicum grasses. Potted plants were grown in soil under well watered conditions, in artificially lit environmentally controlled cabinets or naturally lit greenhouses at varying levels of CO2 enrichment. CO2 enrichment enhanced the dry weight of C3 and C4 Panicum species under optimal light and N supplies, but had no effect on the total leaf N or TNC concentrations. The high-CO2 induced photosynthetic reaction in the C3 species was accompanied by a reduced Rubisco concentration and was related to the conservation of the relative growth rate of the plant. Elevated CO2 had no effect on the photosynthetic capacity of the C4 species, but enhanced its CO2 assimilation rates under high light and N supplies. The effect of elevated CO2 on the leaf and stem anatomy reflected increased carbon supply at high CO2 in the C3 grass, and reduced transpiratory demand at high CO2 in C4 grasses. Consequently, it is clear that both C3 and C4 grasses are likely to be more productive under rising atmospheric CO2 concentrations. Doctor of Philosophy (PhD)

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Dezi, Silvia <1974&gt. "Modelling the effects of nitrogen deposition and carbon dioxide enrichment on forest carbon balance." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3362/1/dezi_silvia_tesi.pdf.

Testo completo

Abstract (sommario):

Atmospheric CO2 concentration ([CO2]) has increased over the last 250 years, mainly due to human activities. Of total anthropogenic emissions, almost 31% has been sequestered by the terrestrial biosphere. A considerable contribution to this sink comes from temperate and boreal forest ecosystems of the northern hemisphere, which contain a large amount of carbon (C) stored as biomass and soil organic matter. Several potential drivers for this forest C sequestration have been proposed, including increasing atmospheric [CO2], temperature, nitrogen (N) deposition and changes in management practices. However, it is not known which of these drivers are most important. The overall aim of this thesis project was to develop a simple ecosystem model which explicitly incorporates our best understanding of the mechanisms by which these drivers affect forest C storage, and to use this model to investigate the sensitivity of the forest ecosystem to these drivers. I firstly developed a version of the Generic Decomposition and Yield (G’DAY) model to explicitly investigate the mechanisms leading to forest C sequestration following N deposition. Specifically, I modified the G’DAY model to include advances in understanding of C allocation, canopy N uptake, and leaf trait relationships. I also incorporated a simple forest management practice subroutine. Secondly, I investigated the effect of CO2 fertilization on forest productivity with relation to the soil N availability feedback. I modified the model to allow it to simulate short-term responses of deciduous forests to environmental drivers, and applied it to data from a large-scale forest Free-Air CO2 Enrichment (FACE) experiment. Finally, I used the model to investigate the combined effects of recent observed changes in atmospheric [CO2], N deposition, and climate on a European forest stand. The model developed in my thesis project was an effective tool for analysis of effects of environmental drivers on forest ecosystem C storage. Key results from model simulations include: (i) N availability has a major role in forest ecosystem C sequestration; (ii) atmospheric N deposition is an important driver of N availability on short and long time-scales; (iii) rising temperature increases C storage by enhancing soil N availability and (iv) increasing [CO2] significantly affects forest growth and C storage only when N availability is not limiting.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Dezi, Silvia <1974&gt. "Modelling the effects of nitrogen deposition and carbon dioxide enrichment on forest carbon balance." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3362/.

Testo completo

Abstract (sommario):

Atmospheric CO2 concentration ([CO2]) has increased over the last 250 years, mainly due to human activities. Of total anthropogenic emissions, almost 31% has been sequestered by the terrestrial biosphere. A considerable contribution to this sink comes from temperate and boreal forest ecosystems of the northern hemisphere, which contain a large amount of carbon (C) stored as biomass and soil organic matter. Several potential drivers for this forest C sequestration have been proposed, including increasing atmospheric [CO2], temperature, nitrogen (N) deposition and changes in management practices. However, it is not known which of these drivers are most important. The overall aim of this thesis project was to develop a simple ecosystem model which explicitly incorporates our best understanding of the mechanisms by which these drivers affect forest C storage, and to use this model to investigate the sensitivity of the forest ecosystem to these drivers. I firstly developed a version of the Generic Decomposition and Yield (G’DAY) model to explicitly investigate the mechanisms leading to forest C sequestration following N deposition. Specifically, I modified the G’DAY model to include advances in understanding of C allocation, canopy N uptake, and leaf trait relationships. I also incorporated a simple forest management practice subroutine. Secondly, I investigated the effect of CO2 fertilization on forest productivity with relation to the soil N availability feedback. I modified the model to allow it to simulate short-term responses of deciduous forests to environmental drivers, and applied it to data from a large-scale forest Free-Air CO2 Enrichment (FACE) experiment. Finally, I used the model to investigate the combined effects of recent observed changes in atmospheric [CO2], N deposition, and climate on a European forest stand. The model developed in my thesis project was an effective tool for analysis of effects of environmental drivers on forest ecosystem C storage. Key results from model simulations include: (i) N availability has a major role in forest ecosystem C sequestration; (ii) atmospheric N deposition is an important driver of N availability on short and long time-scales; (iii) rising temperature increases C storage by enhancing soil N availability and (iv) increasing [CO2] significantly affects forest growth and C storage only when N availability is not limiting.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Liu, Hung-Tsu (Paul). "Physiological limitations to the growth response of bean plants (Phaseolus vulgaris L.) to carbon dioxide enrichment." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30915.

Testo completo

Abstract (sommario):

Previous studies on dwarf bean plants have found a very limited growth response to CO₂ enrichment (Jolliffe and Ehret, 1985; Ehret and Jolliffe, 1985b). There was no increase in leaf area, and leaf injury was observed after about three weeks of CO₂ enrichment (Ehret and Jolliffe, 1985a). Although dry weight was increased, the increase may be limited due to restricted carbon utilization (e.g. no increases in leaf area). In this study, non-photosynthetic limitations, such as the partitioning of dry matter among plant parts, the partitioning of carbon among photosynthetic end products, and the interactive effects of nutrient and carbon supply on growth, that may contribute to the observed growth responses were investigated. Bean plants responded to CO₂ enrichment by increasing their total dry weights. This weight increase was caused by higher growth rate, at least at early growth stages, and higher unit leaf rate. The dry weight increase was mainly in the leaves, and was not evenly distributed among all plant parts. Leaf expansion and branching were not enhanced by CO₂ enrichment. The differential effects of CO₂ enrichment on growth of different parts caused significant increases in specific leaf weight and shoot root ratio, and a decrease in leaf area ratio. These results indicated that the bean plants used in this study have a limited ability to utilize the extra carbon that was fixed under CO₂ enrichment. There were small increases in glucose, fructose, and sucrose concentrations early in the CO₂ treatments. These increases became much larger after three weeks of CO₂ enrichment. The timing of the higher increases in leaf soluble sugars coincided with the timing of increases in stem and roots dry weight. There was also a large increase in starch concentration shortly after plants were transfered to CO₂ enriched condition. The higher starch concentration accounted for the majority of the weight increase in CO₂ enriched leaves, and this starch level was maintained for several days after plants were switched back to ambient CO₂ levels. A ¹⁴C study on the partitioning of carbon between leaf pools showed that carbon transfer out of the storage pool under CO₂ enrichment was limited. CO₂ enrichment had no effects on leaf protein and amino acid concentrations. No difference, or slight increases, were found in inorganic nutrient concentrations per unit leaf area. Plants grown under CO₂ enrichment, however, show a higher loss of nutrients (especially N and K) from older shoot parts (primary leaves and older trifoliates) to younger parts. High NO₃ ̄ supply increased plant dry weight and leaf area under both CO₂ enriched and ambient conditions. The dry weight increases of the stem and roots caused by CO₂ enrichment, however, were much higher and earlier for high NO₃ ̄treated plants. Furthermore, lower leaf starch concentration was also observed for those CO₂ enriched high NO₃ ̄ treated plants. High NO₃ ̄ supply also increased the leaf nutrient concentrations (N, K, Mg, Ca). Increased uptake of nutrients for high NO₃ ̄ treated plants may be partly contributed by the enhanced root growth. In addition to the growth responses, foliar abnormalities developed gradually in beans under CO₂ enrichment. Chlorosis, assessed by a loss in total chlorophyll concentration, was observed in the primary leaves after about three weeks of CO₂ enrichment. The disorder eventually appeared in the oldest trifoliate leaves after more prolonged CO₂ enrichment. The onset of leaf injury was correlated with the timing of the increases in leaf soluble sugars and the redistribution of nutrient elements from the older shoot parts to the younger parts. High NO₃ ̄ supply delayed the development of leaf injury induced by high CO₂. Results in the present studies indicate that growth responses of dwarf bean plants to CO₂ enrichment were affected by the limited carbon partitioning, and the restriction of starch degradation was indicated to be the probable cause. A higher carbon input under CO₂ enrichment may create a higher demand for inorganic elements. Effects of nutrient supply (NO₃ ̄) on growth responses and leaf injury of CO₂ enriched plants suggested that an imbalance between carbon and nutrient input could be partly related to the limited growth responses of dwarf bean plants to CO₂ enrichment. Land and Food Systems, Faculty of Graduate

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Ghannoum, Oula. "Responses of C3 and C4 Panicum grasses to CO2 enrichment." Thesis, View thesis View thesis, 1997. http://handle.uws.edu.au:8081/1959.7/139.

Testo completo

Abstract (sommario):

This project aims at investigating the effect of CO2 enrichment on the growth and gas exchange of C3, C3-C4 and C4 Panicum grasses. Potted plants were grown in soil under well watered conditions, in artificially lit environmentally controlled cabinets or naturally lit greenhouses at varying levels of CO2 enrichment. CO2 enrichment enhanced the dry weight of C3 and C4 Panicum species under optimal light and N supplies, but had no effect on the total leaf N or TNC concentrations. The high-CO2 induced photosynthetic reaction in the C3 species was accompanied by a reduced Rubisco concentration and was related to the conservation of the relative growth rate of the plant. Elevated CO2 had no effect on the photosynthetic capacity of the C4 species, but enhanced its CO2 assimilation rates under high light and N supplies. The effect of elevated CO2 on the leaf and stem anatomy reflected increased carbon supply at high CO2 in the C3 grass, and reduced transpiratory demand at high CO2 in C4 grasses. Consequently, it is clear that both C3 and C4 grasses are likely to be more productive under rising atmospheric CO2 concentrations.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Lukac, Martin. "Effects of atmospheric COâ†2 enrichment on root processes and mycorrhizal functioning in short rotation intensive poplar plantation." Thesis, Bangor University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391756.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Bray, Shirley M. "The interaction between carbon dioxide enrichment and salinity on growth and carbon partitioning in Phaseolus vulgaris L." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/NQ54822.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Edwards, Diane Roselyn. "Towards a plant-based method of guiding CO₂ enrichment in greenhouse tomato." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3328.

Testo completo

Abstract (sommario):

Atmospheric CO₂ enrichment is employed by greenhouse tomato growers to increase fruit yields, and CO₂ applications are managed according to atmospheric set points or CO₂ injection rates. These methods do not immediately focus on the targets of CO₂ applications: plant performance and the regulation of plant carbon status. This thesis explores several plant-based approaches that may have potential for use in the management of CO₂ in greenhouse tomato production. Three plant-based approaches to CO₂ management were explored in commercial and experimental tomato greenhouses. These were: (1) simulation modeling, (2) non-destructive analysis of growth and (3) the status of plant carbon reserves. A cost and benefit analysis (c/b) using simulation modeling was carried out using grower-collected greenhouse environment and yield data. Simulation modeling was useful for retrospectively determining c/b of several CO₂ scenarios. The model was effective in predicting long term yields, but not short term yield variations, which limits its application for CO₂ management. Non-destructive measures of growth: stem length and diameter, leaf area and fruit load were found to be too sluggish for daily CO₂ dosing decision-making. Finally, plants growing under CO₂ enrichment can deposit substantial carbon as starch in their leaves. Plant carbon status was evaluated by determining the spatial distribution of leaf starch in the shoot and by following its variation diurnally and after the onset of CO₂ enrichment. As starch is difficult to measure by a grower, leaf mass per unit area (LMA) was also monitored for assessment as a surrogate measure for starch. Leaves in positions 7 to 9 were identified as the most meaningful in the shoot to sample. Diurnal profiles indicated these leaves carryover substantial starch from one day to the next. Monitoring starch at its peak time of accumulation (14 h to 16 h), at sunset and sunrise will indicate how much the peak starch reserves are used overnight. If starch remains high between peak and sunrise the following day, then the plants are in a carbon-surplus state and CO₂ enrichment could be postponed. For upper canopy leaves LMA is substantially influenced by starch and thus is a promising surrogate.

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Newbery, R. M. "Influence of CO₂ enrichment on the growth and nutritional status of Agrostis capillaris and Calluna." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240455.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Giuntoli, Alberto. "Increased carbon dioxide concentration affects photoinhibition of photosynthesis in wheat and grapevine in the field." Thesis, University of Essex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327070.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Springer, Clint J. "Estimating net photosynthesis and productivity of a loblolly pine forest grown with carbon dioxide enrichment." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3584.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--West Virginia University, 2004. Title from document title page. Document formatted into pages; contains ix, 113 p. : ill. Vita. Includes abstract. Includes bibliographical references.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Bachman, Sarah. "Elevated atmospheric carbon dioxide and precipitation alter ecosystem carbon fluxes over northern mixed-grass prairie at the prairie heating and CO2 enrichment (PHACE) experiment in Cheyenne, Wyoming, USA." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445355711&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Scholefield, Paul Anthony. "Effects of long-term carbon dioxide enrichment on the emission of isoprene from selected plant species." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288942.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Aldarmaki, Naeema Ibrahim Karam Al-Darmaki. "Extraction and enrichment of minor lipid components of palm fatty acid distillate using supercritical carbon dioxide." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3621/.

Testo completo

Abstract (sommario):

Currently the extraction of valuable components from oils is of growing interest. Palm fatty acid distillate is a by-product from palm oil refining process which contains valuable minor components. The scope of the present work was to investigate the enrichment of high value low concentration components of palm fatty acid distillate namely squalene (1.8-2.3 wt.% squalene) using supercritical carbon dioxide as solvent with counter-current packed column kept under isothermal and longitudinal thermal gradient. The overall objective of this work was to explore the effect of extraction process parameters such as pressure, temperature, and solvent to feed ratio to optimize the conditions that lead to high separation efficiency. This work has been centred on the study of the solubility of the main lipid components in supercritical carbon dioxide, isothermal counter-current extraction, longitudinal thermal gradient fractionation and the effect of feed concentration. Solubility studies have been conducted for binary, ternary and quaternary systems as function of state of conditions through the application of a dynamic method. Binary systems of CO2/squalene, CO2/oleic acid, CO2/\( \alpha \)-tocopherol, and CO2/pseudo-component palm olein were measured at temperatures of 313, 333 and 353 K, and at a pressure range of 10 to 30 MPa. A ternary system of CO2/squalene/palm olein and a quaternary system of CO2/squalene/ palm olein/ oleic acid were also investigated at 313 K and pressures of 10 to 25 MPa. Comparison of the ternary system with the binary system showed a decrease in the solubility of squalene, with a corresponding rise in the solubility of palm olein. In the quaternary system, the presence of oleic acid decreased the selectivity of squalene. Extraction of squalene has been carried out on a counter-current glass beads packed column with the dimensions of 11.45 mm internal diameter and 1.5 m of effective height. The pressure and temperature were the operating conditions investigated and they varied from 10 – 20 MPa and 313 – 353K, respectively. Experimentation has demonstrated that squalene high fraction is achievable, however, squalene recovery has been found to be highly dependent on the extraction pressure and temperature. Squalene and free fatty acids content in the extract increased, and triglycerides content decreased during most of the fractionation runs. Longitudinal thermal gradient profiles along the column were investigated for further recovery of squalene, results showed the highest squalene recovery of more than 95% was reached and concentration of squalene was increased from 2wt% in the feed to 16wt% in the top product.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Butler, G. D., B. A. Kimball, and J. R. Mauney. "Populations of the Sweetpotato Whitefly on Cotton Grown in Open-Top Field Carbon Dioxide-Enrichment Chambers." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/204054.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Wees, David. "The effects of carbon dioxide enrichment and aeration of hydroponic nutrient solutions on the growth and yield of lettuce /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66169.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Polastrini, Elisa. "Enrichment of CO2 in marine ecosystem: effects on marine bivalve Chamelea gallina." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

Cerca il testo completo

Abstract (sommario):

Oceans absorb 30% of the anthropogenic CO2 release in the atmosphere (IPCC 2014). With climate change, marine ecosystems are mainly exposed to rising temperature and ocean acidification. The principal consequences of adding CO2 to seawater is to decrease the concentration of carbonate ion and lower pH. These impacts can affect marine calcifying organisms such as bivalves to produce their CaCO3 shell or compromise their fitness. The IPCC proposes Carbon dioxide Capture and Storage (CCS) in the context of a measure for mitigating climate change consequences, however a leakage of CO2 could have negative environmental implications. The research work presented investigates the possible pH effects on marine bivalve C. gallina induced by acidification with a specific aim of assessing how benthic calcifying organisms react to a CO2 leakage or more generally to the coming changes in climate. Potential CO2 leakage could re-suspend high quantities of sediments and contaminants associated with negative effects for marine biota. Therefore, a secondary purpose is to investigate the effects on clams produced by interaction among acidification and an emerging contaminant such as microplastics. Three types of analysis were performed in the study: (1) survival rate of the clam under stressful conditions; (2) physical-chemical analysis of the principal components of shell calcification; (3) histopathological analysis in gills tissues to quantify the induced lesions. The data obtained revealed a significant low survival rate of clam C. gallina in relation to a pH reduction, with a limited ability to form calcified structures and disturbed metabolic activities. The study suggests that acidification induced by CO2 leakage can damage the gills of clams, instead it showed a non significant interaction with microplastics. Future research is needed to understand and predict the biological effects and economic implications for marine ecosystem resulting from CO2 leakage.

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Iost, Regiane [UNESP]. "Problemas fitossanitários e crescimento de duas cultivares de café durante o primeiro ano em experimento FACE (“Free Air Carbon Dioxide Enrichment”)." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/97248.

Testo completo

Abstract (sommario):

Made available in DSpace on 2014-06-11T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-27Bitstream added on 2014-06-13T20:37:47Z : No. of bitstreams: 1 iost_r_me_botfca_parcial.pdf: 110809 bytes, checksum: c0abdcf9aa822016e85666ad00073d89 (MD5) Bitstreams deleted on 2015-06-25T13:01:10Z: iost_r_me_botfca_parcial.pdf,. Added 1 bitstream(s) on 2015-06-25T13:03:27Z : No. of bitstreams: 1 000713993_20160701.pdf: 96541 bytes, checksum: 5abbfa05701cbfcb731f06693b6b568e (MD5) Bitstreams deleted on 2016-07-01T13:02:17Z: 000713993_20160701.pdf,. Added 1 bitstream(s) on 2016-07-01T13:03:16Z : No. of bitstreams: 1 000713993.pdf: 476359 bytes, checksum: b723abff97761ebd0be4765541bf38af (MD5) O clima do planeta vem se alterando gradativamente nas últimas décadas em consequência da intensificação das atividades antrópicas, como a queima de combustíveis fósseis e mudanças no uso da terra, que são responsáveis por alterações em diversos componentes do ambiente, como o dióxido de carbono (CO₂), o ozônio (O3) e a radiação ultravioleta-B (UV-B). Considerando que o CO2 é o gás de efeito estufa que tem maior destaque devido ao maior volume de emissões, os efeitos do aumento da concentração de CO₂ do ar (duas condições: ambiente e elevada em relação à concentração de CO₂ do ar) foram avaliados sobre os problemas fitossanitários e o crescimento de plantas jovens de café em duas cultivares (Catuaí Vermelho IAC 144 e Obatã IAC 1669-20) durante o primeiro ano de injeção do gás em FACE (“Free Air Carbon Dioxide Enrichment”). O experimento foi realizado no campo experimental da Embrapa Meio Ambiente, em Jaguariúna, (latitude 22°71’90’’S, longitude 47°02’10’’W, altitude de 570 m), sendo composto por 12 parcelas octogonais com laterais de quatro metros e 10 metros de diâmetro. A injeção de CO2 é feita no período diurno, das 7 às 17h, em seis parcelas por meio de bicos injetores localizados nos lados das parcelas a 0,5m de altura do solo. A injeção só é feita com ventos entre 0,5 e 4,5 m/s controlada por meio de válvulas. O monitoramento e o controle do sistema são realizados por uma rede de comunicação sem fio. O aumento da concentração de CO2 do ar não teve efeito sobre o crescimento das plantas jovens de café para as duas cultivares para as variáveis: número total de folhas, número total de ramos e diâmetro do colo. Apenas o número total de nós e a altura das plantas apresentaram diferenças significativas quanto... The earth's climate has been changing gradually over the last decades as a result of the intensification of human activities such as burning fossil fuels and changes in land use, which are responsible for changes in various components of the environment, such as carbon dioxide (CO₂), ozone (O3) and ultraviolet B (UV-B). Considering that CO2 is the greenhouse gas that is more prominent due to higher emissions, the effects of increasing the concentration of CO₂ in the air (two conditions: environment and high relative concentration of CO₂ air) were evaluated on the phytosanitary problems and growth young coffee plants in both cultivars (Catuai Vermelho IAC 144 and Obatã IAC 1669-20) during the first year of gas injection in FACE (Free Air Carbon Dioxide Enrichment). The experiment was conducted at the experimental field of Embrapa Environment in Jaguariuna, (latitude 22°71'90'' S, longitude 47°02'10''W, altitude 570 m), comprising 12 plots octagonal side four meters and 10 meters in diameter. The CO2 injection is made during the day, from 7 to 17h, in six installments through nozzles located on the sides of the plots at 0.5 m height from the ground. The injection is made only with winds between 0.5 and 4.5 m/s controlled by valves. The monitoring and control system are realized by a network of wireless communication... (Complete abstract click electronic access below)

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Iost, Regiane 1983. "Problemas fitossanitários e crescimento de duas cultivares de café durante o primeiro ano em experimento FACE ("Free Air Carbon Dioxide Enrichment") /." Botucatu, 2013. http://hdl.handle.net/11449/97248.

Testo completo

Abstract (sommario):

Orientador: Raquel Ghini Banca: Antonio Carlos Maringoni Banca: Flávia Rodrigues Alves Patrício Resumo: O clima do planeta vem se alterando gradativamente nas últimas décadas em consequência da intensificação das atividades antrópicas, como a queima de combustíveis fósseis e mudanças no uso da terra, que são responsáveis por alterações em diversos componentes do ambiente, como o dióxido de carbono (CO₂), o ozônio (O3) e a radiação ultravioleta-B (UV-B). Considerando que o CO2 é o gás de efeito estufa que tem maior destaque devido ao maior volume de emissões, os efeitos do aumento da concentração de CO₂ do ar (duas condições: ambiente e elevada em relação à concentração de CO₂ do ar) foram avaliados sobre os problemas fitossanitários e o crescimento de plantas jovens de café em duas cultivares (Catuaí Vermelho IAC 144 e Obatã IAC 1669-20) durante o primeiro ano de injeção do gás em FACE ("Free Air Carbon Dioxide Enrichment"). O experimento foi realizado no campo experimental da Embrapa Meio Ambiente, em Jaguariúna, (latitude 22°71'90''S, longitude 47°02'10''W, altitude de 570 m), sendo composto por 12 parcelas octogonais com laterais de quatro metros e 10 metros de diâmetro. A injeção de CO2 é feita no período diurno, das 7 às 17h, em seis parcelas por meio de bicos injetores localizados nos lados das parcelas a 0,5m de altura do solo. A injeção só é feita com ventos entre 0,5 e 4,5 m/s controlada por meio de válvulas. O monitoramento e o controle do sistema são realizados por uma rede de comunicação sem fio. O aumento da concentração de CO2 do ar não teve efeito sobre o crescimento das plantas jovens de café para as duas cultivares para as variáveis: número total de folhas, número total de ramos e diâmetro do colo. Apenas o número total de nós e a altura das plantas apresentaram diferenças significativas quanto... (Resumo completo, clicar acesso eletrônico abaixo) Abstract: The earth's climate has been changing gradually over the last decades as a result of the intensification of human activities such as burning fossil fuels and changes in land use, which are responsible for changes in various components of the environment, such as carbon dioxide (CO₂), ozone (O3) and ultraviolet B (UV-B). Considering that CO2 is the greenhouse gas that is more prominent due to higher emissions, the effects of increasing the concentration of CO₂ in the air (two conditions: environment and high relative concentration of CO₂ air) were evaluated on the phytosanitary problems and growth young coffee plants in both cultivars (Catuai Vermelho IAC 144 and Obatã IAC 1669-20) during the first year of gas injection in FACE ("Free Air Carbon Dioxide Enrichment"). The experiment was conducted at the experimental field of Embrapa Environment in Jaguariuna, (latitude 22°71'90'' S, longitude 47°02'10''W, altitude 570 m), comprising 12 plots octagonal side four meters and 10 meters in diameter. The CO2 injection is made during the day, from 7 to 17h, in six installments through nozzles located on the sides of the plots at 0.5 m height from the ground. The injection is made only with winds between 0.5 and 4.5 m/s controlled by valves. The monitoring and control system are realized by a network of wireless communication... (Complete abstract click electronic access below) Mestre

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Iost, Regiane [UNESP]. "Café arábica em experimento tipo FACE ('Free Air Carbon Dioxide Enrichment'): intensidade da ferrugem e do bicho-mineiro e crescimento da planta." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151156.

Testo completo

Abstract (sommario):

Submitted by REGIANE IOST (regianeiost_agro@yahoo.com.br) on 2017-07-18T22:32:11Z No. of bitstreams: 1 TESE DOUTORADO REGIANE IOST.pdf: 1597027 bytes, checksum: 9d0d42f8ace87258f652a33d2c58a13a (MD5) Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-07-19T18:18:25Z (GMT) No. of bitstreams: 1 iost_r_dr_bot.pdf: 1597027 bytes, checksum: 9d0d42f8ace87258f652a33d2c58a13a (MD5) Made available in DSpace on 2017-07-19T18:18:25Z (GMT). No. of bitstreams: 1 iost_r_dr_bot.pdf: 1597027 bytes, checksum: 9d0d42f8ace87258f652a33d2c58a13a (MD5) Previous issue date: 2017-02-21 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Nas últimas décadas o clima do planeta vem se alterando gradativamente em consequência da mudança climática, devido principalmente, à intensificação das atividades antrópicas, como a queima de combustíveis fósseis e mudanças no uso da terra, as quais são responsáveis por alterações em diversos componentes do ambiente, como o dióxido de carbono (CO₂), o metano, o óxido nitroso e outros gases de efeito estufa. Considerando que o CO2 é o gás de efeito estufa que tem maior importância devido ao maior volume de emissões, os efeitos do enriquecimento do ar com CO₂[duas condições: concentração ambiente (nas faixas 360-450ppm) e concentração enriquecida (entre 490 ppm e 620 ppm)] foram avaliados sobre o desenvolvimento de plantas de café e sobre a ferrugem do cafeeiro e bicho-mineiro na cultivar “Catuaí Vermelho IAC 144” em experimento do tipo FACE (“Free Air Carbon Dioxide Enrichment”). O experimento foi composto por 12 parcelas octogonais com 10 metros de diâmetro, das quais seis foram enriquecidas com CO2 e seis permaneceram na concentração ambiente. As avaliações foram realizadas nos anos de 2013, 2014 e 2015. Para o desenvolvimento da cultura foram avaliadas a altura das plantas, o diâmetro do colo das plantas e o número de folhas nos ramos. Para os problemas fitossanitários foram avaliados a ferrugem do cafeeiro e o bicho-mineiro, ambos por meio da incidência. Em condições de enriquecimento do ar com CO2 a altura das plantas e o diâmetro do caule foram maiores, nos três anos avaliados. Não houve diferença estatística para o número de folhas em todo o período avaliado. A incidência de bicho-mineiro foi maior em condições ambientes, enquanto a incidência da ferrugem do cafeeiro foi semelhante em ambas as condições. In recent decades the planet's climate has been gradually changing as a result of climate change, mainly due to the intensification of anthropogenic activities, such as the burning of fossil fuels and changes in land use, which are responsible for changes in various components of the environment, such as carbon dioxide (CO2), methane, nitrous oxide and other greenhouse gases. Considering that CO2 is the most important greenhouse gas due to higher emissions, the effects of CO2 enrichment [two conditions: ambient concentration (between 360ppm and 490ppm) and enriched concentration (between 490ppm and 620ppm)] were evaluated on the development of coffee plants and on coffee leaf rust and leaf miner in the "Catuaí Vermelho IAC 144" cultivar in a Free Air Carbon Dioxide Enrichment (FACE) experiment. The experiment was composed of 12 octagonal plots with 10 meters in diameter, of which six were enriched with CO2 and six remained in the ambient concentration. The evaluations were carried out in the years of 2013, 2014 and 2015. For the development of the crop were evaluated height of plants, stem diameter and number of leaves in the branches. For the phytosanitary problems, was evaluated the incidence of coffee leaf rust and leafminer incidence. In CO2 enrichment conditions, plant height and stem diameter were higher in the three years evaluated. There was no statistical difference for the number of leaves throughout the evaluated period. The incidence of leaf miner was higher in environmental conditions, while the incidence of coffee leaf rust was similar in both conditions.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Iost, Regiane 1983. "Café arábica em experimento tipo FACE ('Free Air Carbon Dioxide Enrichment') : intensidade da ferrugem e do bicho-mineiro e crescimento da planta /." Botucatu, 2017. http://hdl.handle.net/11449/151156.

Testo completo

Abstract (sommario):

Orientador: Raquel Ghini Coorientador: Wagner Bettiol Banca: Edson Luiz Furtado Banca: Flávia Rodrigues Alves Patrício Banca: Kátia de Lima Nechet Banca: Dartanhã José Soares Resumo: Nas últimas décadas o clima do planeta vem se alterando gradativamente em consequência da mudança climática, devido principalmente, à intensificação das atividades antrópicas, como a queima de combustíveis fósseis e mudanças no uso da terra, as quais são responsáveis por alterações em diversos componentes do ambiente, como o dióxido de carbono (CO₂), o metano, o óxido nitroso e outros gases de efeito estufa. Considerando que o CO2 é o gás de efeito estufa que tem maior importância devido ao maior volume de emissões, os efeitos do enriquecimento do ar com CO₂[duas condições: concentração ambiente (nas faixas 360-450ppm) e concentração enriquecida (entre 490 ppm e 620 ppm)] foram avaliados sobre o desenvolvimento de plantas de café e sobre a ferrugem do cafeeiro e bicho-mineiro na cultivar "Catuaí Vermelho IAC 144" em experimento do tipo FACE ("Free Air Carbon Dioxide Enrichment"). O experimento foi composto por 12 parcelas octogonais com 10 metros de diâmetro, das quais seis foram enriquecidas com CO2 e seis permaneceram na concentração ambiente. As avaliações foram realizadas nos anos de 2013, 2014 e 2015. Para o desenvolvimento da cultura foram avaliadas a altura das plantas, o diâmetro do colo das plantas e o número de folhas nos ramos. Para os problemas fitossanitários foram avaliados a ferrugem do cafeeiro e o bicho-mineiro, ambos por meio da incidência. Em condições de enriquecimento do ar com CO2 a altura das plantas e o diâmetro do caule foram maiore... (Resumo completo, clicar acesso eletrônico abaixo) Abstract: In recent decades the planet's climate has been gradually changing as a result of climate change, mainly due to the intensification of anthropogenic activities, such as the burning of fossil fuels and changes in land use, which are responsible for changes in various components of the environment, such as carbon dioxide (CO2), methane, nitrous oxide and other greenhouse gases. Considering that CO2 is the most important greenhouse gas due to higher emissions, the effects of CO2 enrichment [two conditions: ambient concentration (between 360ppm and 490ppm) and enriched concentration (between 490ppm and 620ppm)] were evaluated on the development of coffee plants and on coffee leaf rust and leaf miner in the "Catuaí Vermelho IAC 144" cultivar in a Free Air Carbon Dioxide Enrichment (FACE) experiment. The experiment was composed of 12 octagonal plots with 10 meters in diameter, of which six were enriched with CO2 and six remained in the ambient concentration. The evaluations were carried out in the years of 2013, 2014 and 2015. For the development of the crop were evaluated height of plants, stem diameter and number of leaves in the branches. For the phytosanitary problems, was evaluated the incidence of coffee leaf rust and leafminer incidence. In CO2 enrichment conditions, plant height and stem diameter were higher in the three years evaluated. There was no statistical difference for the number of leaves throughout the evaluated period. The incidence of leaf miner was higher in environmental conditions, while the incidence of coffee leaf rust was similar in both conditions ... Doutor

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Olsson, Per. "Effects of fertilisation on rhizospheric and heterotrophic soil CO2 efflux in boreal Norway spruce stands /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/10064860.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Slaney, Michelle. "Impact of elevated temperature and [CO₂] on spring phenology and photosynthetic recovery of boreal Norway spruce /." Alnarp : Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200603.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Lin, Chia-Wei, and 林嘉偉. "Carbon dioxide enrichment PDMS/PSf composite membrane." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/cmwuq8.

Testo completo

Abstract (sommario):

碩士 中原大學 化學工程研究所 106 After the industrial revolution in the 18th century, due to the extensive factory, greenhouse gases such as carbon dioxide (CO2), methane (CH4), ozone (O3) and nitrogen oxides (NOX) were produced which have caused serious global climate and affect the people’s lives. Therefore, many researchers have used various technologies to capture the greenhouse gases to improve global warming. Food is the most basic factor for human survival. Global warming climate anomalies will reduce agricultural production and create another food crisis that threatens human survival. In recent years, membrane separation technology has received more and more attention. Therefore, we hope to use membrane technology to capture carbon dioxide. Carbon dioxide enriched air is used to promote the photosynthesis of crops to accelerate the growth of crops and shorten the production cycle of crops. Both food shortage and global warming can be solved by carbon dioxide enrichment cultivation. In this study, carbon dioxide-enriched composite membranes were prepared and used in agriculture to supply a large amount of carbon dioxide concentrated air. The carbon dioxide concentration of the original PDMS/PSf composite film is increased. But the efficiency cannot meet the requirements for promoting the growth of crops (CO2 concentration is greater than 800ppm). So we use different methods to modified the composite membrane. The results show that the concentration of carbon dioxide in permeate of the support PSf membrane is about 452 ppm, and the gas flux is about 44320 GPU. After coating PDMS and adjusting the concentration of cross-linking agent, UV/O3 treatment time and heat treatment conditions, the PDMS/PSf composite membrane, the CO2 gas flux decrease to 2336 GPU, but the carbon dioxide concentration increased to 814 ppm. FESEM, FTIR, SEM EDX, XPS, WCA, etc., were used to analyze the PDMS/PSf composite membrane. In the study, the prepared film was actually applied to greenhouse cultivation crops to prove that enriched carbon dioxide air promoted crops. The results of this study show that carbon dioxide enrichment membrane has considerable potential for the growth of crops.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Li, Wan-Hua, and 李婉華. "Carbon dioxide enrichment PEBAX/MOF composite membrane for CO2 separation." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mj8qyu.

Testo completo

Abstract (sommario):

碩士 中原大學 化學研究所 107 In this study, metal organic frameworks (MOFs) with different pore sizes or with different functional groups and poly(ether-block-amide) (Pebax-1657) were used to treat organic metal skeletons through drying-free methods. Mixing to prepare a mixed matrix film (MMM), the different loading ratio of the metal organic frameworks was studied, and the mass percentage was 1 wt% to 30 wt%. The mixed matrix membrane showed an improvement compared with the pure polymer membrane. CO2 permeability and CO2 / N2 selectivity. By processing the metal organic frameworks without drying, the results obtained can be clearly observed. When the loading of ZIF-8 is increased, the selectivity of gas separation is gradually increased, which is 20% higher than the literature. Use other metal organic frameworks such as UiO-66, NH2-UiO-66, MIL-53 (Al), A520, MIL-68 (Al), and MIL-100 (Fe) at 5 wt% loading (based on polymer) The polyether polyamine block copolymer is mixed the metal organic frameworks is processed in a drying-free manner to prepare a mixed matrix membrane, and then the gas separation performance test is performed, and the highest CO2 / N2 separation efficiency is 85.94 obtained by P-UiO-66., permeate flux 189.77 (barrer), higher than the 2008 Robeson’s Upper bound, to obtain a high permeability and high selectivity mixed matrix membrane.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Wu, Chuan-Hsiang, and 吳詮翔. "Ethyl cellulose composite membranes for carbon dioxide separation and oxygen enrichment processes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/r8d83s.

Testo completo

Abstract (sommario):

碩士 國立宜蘭大學 化學工程與材料工程學系碩士班 103 In this study, the oligomer, glycerol propoxylate-block-ethoxylate (GP-b-E) or the amino-modified hollow silica (NH2-HS) with different shaps as the additives were added in the ethyl cellulose (EC) polymer to prepare a series of EC composite membranes. These composite membranes were applied to the gas separation processes. The effects of the concentration of casting solution and the oligomer content on the properties and gas separation performance of membrane were investigated. The effects of the shape, surface amino-modification, and content of hollow silica on the properties and gas separation performance of membrane were also studied in this study. Scanning electron microscope (SEM) was used to observe the morphologies of the membranes and hollow silica. Fourier transform infrared (FTIR) was used to analyze the surface chemical structure of amino-modified hollow silica. Energy Dispersive X-ray spectrometer (EDX) was used to observe the distribution of hollow silica in the membrane. Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) were used to analyze the thermal properties of the membranes. Tensile tester (Instron) was used to measure the mechanical properties of the membranes. The gas sorption measurement was carried out by the microbalance to determine the adsorbed amount of gas. In the addition system of GP-b-E oligomer, from the SEM observation, the addition of the GP-b-E oligomer in the EC membrane causes the membrane morphology converts the more closed porous structure to the more connected porous structure. With an increase in the added amount of GP-b-E, connected porous structure in the membrane increased. From the results of the DSC and mechanical property measurements, the addition of the GP-b-E oligomer causes a decrease in the melting point, Young's modulus, and tensile strength and an increase in the elongation. From the results of the gas permeation experiments, the addition of the oligomer having the ether groups in the EC membrane can effectively promote the permeability coefficients of carbon dioxide and oxygen. The EC/GP-b-E composite membrane prepared by the addition content of EC:GP-b-E=1:0.5 (by weight) has the desirable gas separation performance which is the carbon dioxide and oxygen permeability coefficients of 1506.3 barrer and 228.5 barrer and the carbon dioxide/nitrogen and oxygen/nitrogen selectivities of 17.5 and 2.7, respectively. From the analysis of the solution-diffusion mechanism, the gas permeability coefficient and selectivity of the EC/GP-b-E composite membrane are dominated by it’s the gas diffusivity coefficient and diffusivity selectivity. In the addition system of HS and NH2-HS, from the results of SEM observation and FTIR analysis, the amino-modified hollow silica with different shaps was prepared successfully. From the SEM observation and EDX analysis, the spherical NH2-HS can be distributed in the EC membrane uniformly. From the result of mechanical property measurement, the addition of the spherical NH2-HS causes a decreases in Young's modulus, tensile strength and elongation. From the TGA and DSC measurements, the addition of the spherical NH2-HS in the EC membrane enhances the thermal stability of the membrane slightly but decreases the glass transition temperature (Tg) and melting point (Tm). From the results of the gas permeation experiments, the addition of the spherical HS in the EC membrane can effectively promote the permeability coefficients of carbon dioxide and oxygen. The EC/spherical NH2-HS composite membrane prepared by the addition content of EC:spherical NH2-HS=1:0.1 (by weight) has the desirable gas separation performance which is the carbon dioxide and oxygen permeability coefficients of 190.1 barrer and 33.7 barrer and the carbon dioxide/nitrogen and oxygen/nitrogen selectivities of 19.7 and 3.5, respectively.

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Lee, Dal-Hoon. "Energy saving through integrated greenhouse climate control for heating, ventilation and carbon dioxide enrichment." Thesis, 1993. http://hdl.handle.net/2429/4987.

Testo completo

Abstract (sommario):

A computer model was developed for predicting heating, ventilation and CO 2 enrichment requirements for a standard tomato greenhouse range located in the Fraser valley of British Columbia. Predicted and measured data were compared for typical cases of outside weather conditions. The mathematical model which is comprised of heat and mass balances for the greenhouse thermal environment and crop photosynthesis has yielded reasonably accurate simulation results compared to observed values. Heating requirement was predicted to within 10-14% for three typical cases of weather conditions, but deviated by 35% from actual energy consumption data under one situation(Case #3). Predicted ventilation demand also followed closely the trend of observed vent openings data, except for Case #4 . Energy saving is achieved in different manners for the four cases.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Lutze, Jason Lewis. "Carbon and nitrogen relationships in swards of Danthonia richardsonii in response to carbon dioxide enrichment and nitrogen supply." Phd thesis, 1996. http://hdl.handle.net/1885/10981.

Testo completo

Abstract (sommario):

Atmospheric C0₂ concentrations are increasing steadily, although not fast enough to account for all anthropogenic emissions. Uptake of extra carbon by the terrestrial biosphere in response to the CO₂ concentration increase may, in turn, be moderating the rate of increase. However, there are uncertainties pertaining to the ability of natural ecosystems to respond to this increase in terms of productivity and carbon sequestration, when productivity is restricted by nitrogen availability. This study provides experimental data on the response of microcosms of the wild, C₃ Australian grass Danthonia richardsonii Cashmore to C0₂ enrichment over 4 years of growth in the Canberra Phytotron, when productivity was restricted by low nitrogen availability. Complementary experiments with isolated plants elucidated the effects of C0₂ enrichment on carbon and nitrogen acquisition and allocation. The general growth response of D. richardsonii to C0₂ enrichment was compared with other C₃ grasses in further isolated plant experiments. Microcosms accumulated extra carbon under C0₂ enrichment. Microcosms were supplied continuously with 3 productivity limiting rates of N supply, 2.2, 6.7 or 19.8 g N m⁻² yr⁻¹, at atmospheric C0₂ concentrations of 359 or 718 μLL⁻¹. Controlled quantities of water were supplied and periodic drought imposed. The effect of C0₂ on total plant-soil system carbon was highly significant at all N supply rates, and did not diminish over time. Increased microcosm carbon was attained without a persistent increase in leaf area index, and above ground live carbon was not increased by C0₂ enrichment after the first year. Leaf turnover was higher at high C0₂, as was the amount of total senesced leaf. Root carbon was lower at high C0₂ at lowand mid-N, but higher at high-N. Rates of water-use were lower at high C0₂, resulting in a higher soil water content. At the higher N levels both soil microbial and non-microbial carbon were increased at high C0₂, while total soil carbon and non-microbial carbon were increased at low-N. Low- and mid-N microcosms gained significant amounts of nitrogen from the environment, attributed to a combination of nitrogen deposition and free-living nitrogen fixation. Nitrogen loss from the high-N microcosms was lower at high C0₂. Green leaf nitrogen concentration and total standing leaf nitrogen were reduced by C0₂ enrichment. Increased C:N ratios of senesced leaf at high C0₂ resulted in decreased decomposition (cumulated microbial respiration) in vitro. This was not reflected at the microcosm level, possibly owing to increased soil water content and microbial biomass. High C0₂ increased carbon accumulation by isolated plants when grown at several N levels (0.05, 0.2, 0.5 or 6 mg N plan⁻¹ day⁻¹ ) over 37 days. Net assimilation rate and leaf nitrogen productivity were increased at high C0₂• Whole plant (g N g⁻¹ C) and leaf nitrogen concentrations (g N g⁻¹ C or g N m⁻² ) were reduced by C0₂ enrichment when nitrogen supply restricted growth. Allometric relationships showed that carbon allocation and root nitrogen concentration (g N g⁻¹ C) were not affected by C0₂ enrichment. Nitrogen allocation to root, as a proportion of total plant nitrogen was increased at high C0₂, and leaf to root surface area ratio reduced, indicating a shift in investment from processes involved with carbon acquisition to those involved with nitrogen acquisition. The differences were small at the higher rates of N supply. As an isolated plant, D. richardsonii exhibited a similar response in dry matter or carbon accumulation to C0₂ enrichment ( -360 μL L⁻¹ and -720 μLL⁻¹ ) as other grasses when nitrogen - supply was abundant (Hoagland solution) or growth limiting (0.4 or 1.6 mg N planf1 day"1 ) over 71 days. Total transpiration (g H₂0 planf1 ) was reduced, and transpiration efficiency (g C g-1 H20) increased at high C0₂ in plants experiencing nitrogen limitation, but was not determined in the plants supplied with abundant N. D. richardsonii showed real increases in nitrogen use efficiency at high C0₂. This was expressed at the microcosm level as increases in total plant-soil system carbon gain a high C0₂ at all rates of nitrogen supply. The magnitude of this response is large enough to account for a significant proportion of global anthropogenic carbon emissions, if applicable to all ecosystems in the field.

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Brown, ZA. "The effects of elevated carbon dioxide on greenhouse gas emissions from a temperate pasture." Thesis, 2020. https://eprints.utas.edu.au/34798/1/Brown_whole_thesis.pdf.

Testo completo

Abstract (sommario):

Global surface temperatures have been rising since the pre-industrial era and are predicted to continue rising due to the positive radiative forcing of greenhouse gases in the atmosphere. The atmospheric concentration of carbon dioxide (CO\(_2\)), the gas responsible for most of this warming, has increased since the industrial revolution due to the burning of fossil fuels and land use change. The concentration of nitrous oxide (N\(_2\)O), a potent greenhouse gas with substantially higher global warming potential than CO\(_2\) over a 100-y horizon, has similarly increased due to agriculture and nitrogenous fertiliser use. In addition to warming the earth’s surface, elevated CO\(_2\) (eCO\(_2\)) may change terrestrial carbon (C) and nitrogen (N) cycling due to plant responses to increased C availability. Plants respond to eCO\(_2\) in two ways: through increased biomass production and increased water-use efficiency. These responses may alter the availability of C, N and water in soils, which could affect microbial activity through shifts in substrate availability and soil aerobic status. As many processes mediated by microbes release CO\(_2\) and N\(_2\)O, it is likely that both plant responses to eCO\(_2\) could alter these gas fluxes. Soils are the largest source of CO\(_2\) and N\(_2\)O, making it essential that accurate predictions of future greenhouse gas emissions include the response of these processes to eCO\(_2\). Using a temperate pasture dominated by Lolium perenne, this study measured the impact of three levels of CO\(_2\) concentration (400, 475 and 550 μmol CO\(_2\) mol\(^{-1}\)) on the emission of CO\(_2\) and N\(_2\)O. Additionally, water supply was independently controlled via irrigation treatments (adequate, excess = +20% and limit = -40%) to determine if CO\(_2\)-effects on soil processes were driven by plant production, soil water content or both. Plant biomass was increased under 550 μmol CO\(_2\) mol\(^{-1}\) relative to ambient due entirely to greater root growth but no similar change in production was present under 475 μmol CO\(_2\) mol\(^{-1}\). Plant N requirements were increased under eCO\(_2\) relative to ambient, resulting in additional N immobilised in plantbiomass under eCO\(_2\) and substantially lower soil mineral N availability. Consequently, N\(_2\)O emissions were never higher under eCO\(_2\) than ambient and were often lower. This effect dramatically reduced N\(_2\)O emissions from this pasture with the strongest effect in the week following fertiliser application when emissions were highest. Under eCO\(_2\), soil CO\(_2\) emissions were higher than at 400 μmol CO\(_2\) mol\(^{-1}\), though mean emissions were similar between 475 and 550 μmol CO\(_2\) mol\(^{-1}\). Similarly, the rate of root decomposition in soils under eCO\(_2\) was higher than in control plots as was the loss of soil C. The CO\(_2\)-effect on both CO\(_2\) and N\(_2\)O emissions was independent of soil water content, demonstrating that the CO\(_2\)-effect on plant production and organic matter inputs drove the processes underlying these fluxes. Therefore, eCO\(_2\) had a strong effect on the emission of CO\(_2\) and N\(_2\)O from this temperate pasture. In particular, N\(_2\)O emissions were suppressed by the CO\(_2\)-effect on plant N immobilisation and CO\(_2\) emissions were accelerated due to increased belowground C input. Importantly, the effects of soil water content on these emissions were absent in this system entirely, suggesting that the CO\(_2\)-effect on plant production can have a substantial impact on greenhouse gas emissions from temperate pastures.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Chomba, Bernard Malata. "Carbon dioxide enrichment and the role of carbohydrate reserves in root growth potential of cold-stored Engelmann spruce (Picea Engelmannii Parry) seedlings." Thesis, 1992. http://hdl.handle.net/2429/3313.

Testo completo

Abstract (sommario):

Two experiments were conducted to examine the role of carbohydrate reserves in spring root growth potential (RGP)of Engelmann spruce (Picea engelmannii Parry) seedlings. In the first experiment, the effects of pre-storage carbon dioxide enrichment (CE) on total non-structural carbohydrates (TNC) and post-storage root growth were studied. Seedlings were grown from seed for 202 days in growth chambers with ambient (340 μL•L-1) and CO2 enriched(1000 μL•L-1) air. Reciprocal transfers between treatments took place at 60 and 120 days. Photoperiod was reduced at100 days to induce bud set. After 180 days seedlings were hardened-off for storage at -5°C. At 268 and 327 days, seedlings were planted in a growth chamber in three water baths. New roots >5 mm long were counted after 28 days growth. Seedlings were also assessed for bud break every two days. At each planting time, and at 80, 120, 140, and 202days, seedlings were randomly selected from each of the CO2 treatments and harvested for analysis of starch and soluble sugar content. Growth data were also collected. In the second experiment, the relative contributions of reserve carbon and current photosynthate to new root growth were studied. Seedlings were raised using standard nursery procedures up to bud set (end of September, 1990). Seedlings were then moved into a growth chamber and placed in four Plexiglas boxes for stable carbon isotope labelling. Two boxes received ambient CO2 with normal isotopic composition [More abstracts follows]

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Attavanich, Witsanu. "Essays on the Effect of Climate Change on Agriculture and Agricultural Transportation." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10493.

Testo completo

Abstract (sommario):

This dissertation analyzes the impact of climate, and atmospheric carbon dioxide (CO2) on crop yields and grain transportation. The analysis of crop yields endeavors to advance the literature by statistically estimating the effects of atmospheric carbon dioxide (CO2) on observed crop yields. This is done using an econometric model estimated over pooled historical data for 1950-2009 and data from the free air CO2 enrichment experiments. The main findings are: 1) yields of soybeans, cotton, and wheat directly respond to the elevated CO2, while yields of corn and sorghum do not; 2) the effect of crop technological progress on mean yields is non-linear; 3) ignoring atmospheric CO2 in an econometric model of crop yield likely leads to overestimates of the pure effects of climate change and technological progress on crop yields; and 4) average climate conditions and climate variability contribute in a statistically significant way to average crop yields and their variability. To examine climate change impacts on grain transportation flows, this study employs two modeling systems, a U.S. agricultural sector model and an international grain transportation model, with linked inputs/outputs. The main findings are that under climate change: 1) the excess supply of corn and soybeans generally increases in Northern U.S. regions, while it declines in Central and Southern regions; 2) the Corn Belt, the largest producer of corn in the U.S., is anticipated to ship less corn; 3) the importance of lower Mississippi River ports, the largest current destination for U.S. grain exports, diminishes under the climate change cases, whereas the role of Pacific Northwest ports, Great Lakes ports, and Atlantic ports is projected to increase; 4) the demand for grain shipment via rail and truck rises, while demand for barge transport drops.

Gli stili APA, Harvard, Vancouver, ISO e altri

Tesi sul tema "Carbon dioxide enrichment"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili