| 471. |
|
|
| 472. |
|
|
| 473. |
- Larsson, Anna-Carin, et al.
(författare)
-
Inhibit Fire with Molecules from Nature - Application on Textiles
- 2024
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this project was to find new environmentally friendly, and safe flame retardants(FR) from bio-based resources such as agricultural waste. The intended application of the FRs was on textiles. Textiles are used in many different consumer products such as clothes, blankets, carpets, bedsheets, and upholstery, and since they are combustible, they will contribute to a large fire load in a room. One way to increase fire safety in homes and public buildings is to use flame retardants. They can delay the onset of a fire, or reduce the rate of fire spread, which gives opportunity for people to extinguish the fire, or escape in time. However, many flame retardants have been banned because they are bad for the health and/or the environment. Phytic acid (PA), which is used by plants to store phosphorus, was combined with a few molecules from the group of purines, which are naturally occurring in living systems, and consequently safe. Commonly known purines are caffeine, theobromine, and theophylline, which are found in coffee, tea and chocolate. Other purines are guanine and adenine, which are building blocks in DNA.Initially, screening tests were performed where PA and different purines were mixed in various ratios and applied on cotton, polyester, or wool. Burning tests and microscale combustion calorimetry (MCC) were used to assess the FR ability. Based on the results from the screening tests, the best mixtures were selected for further testing. The selected mixtures were PA with theophylline (TP) on cotton, and PA with adenine (AD) on cotton and polyester.In the second phase of the project, the selected mixtures were investigated with cone calorimetry to get information on their heat release properties, and with thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to get more detailed information on decomposition temperatures and processes. Nuclear magnetic resonance (NMR) was used to get additional information on the decomposition processes. Scanning electron microscopy (SEM) in combination with energy-dispersive X-ray analysis (EDX) was used to confirm the presence of both PA and purine on the textile, and to compare the surface morphology before and after FR treatment and burning.Finally, medium scale fire demonstration experiments with a mock-up chair were performed on the best mixture (PA-AD) on cotton and polyester to validate that the small and medium scale experiments are applicable also in scales that are relevant for end-use. The mixtures showed overall good FR performance, but the best result was on cotton. The results from methods where milligram size samples were used could be scaled up to fire demonstration tests. The main mechanism of action for the FR was charring the textile surface to reduce the amount of flammable pyrolysis gases, but the FR also worked by forming gases which dilute the oxygen and thus prevents the burning process. Endothermic reactions, e.g., degradation of the material, cools the material so that it will be more difficult to ignite, and formation of free radicals can stop the pyrolysis gases before they can react with the oxygen. Overall, the result was a self-extinguishing FR. The FR can also easily be applied on a textile by dipping the item in an aqueous solution.
|
|
| 474. |
- Meinhold, Guido, et al.
(författare)
-
Composition and provenance of upper Neoproterozoic and Cambrian sediments from Finnmark, Arctic Norway : Insights from a multi-method approach on the Digermulen Peninsula
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The remote Digermulen Peninsula by the Tanafjorden of north-eastern Finnmark, Arctic Norway, contains an almost complete sedimentary record across the Ediacaran–Cambrian transition as well as microfossils, macrofossils and trace fossils for studying the Ediacaran biota and the Cambrian radiation. It is one of the few localities worldwide and the only locality in Scandinavia where Ediacara-type fossils have been found. The site was located at the edge of Baltica during the Ediacaran–Cambrian transition, where potentially the dramatic climatic turnover from icehouse to greenhouse conditions can be deduced and tied to large-scale plate tectonics. The Digermulen Peninsula was first studied in the 1930s by Sven Føyn, who also published a geological map in 1937, emended by Harold G. Reading in 1959. In the following years, more detailed mapping was carried out by students from Oxford University. The exposed rocks on the Digermulen Peninsula belong to the Vestertana and Digermulen groups of the Lower Allochthon overlying the Baltic Shield. The succession consists mainly of quartz-rich sandstones and mudrocks. Deposition took place in various environments including fluvial, shallow marine and deeper marine settings. As shown by previous studies using palaeocurrent data, sediment supply was from the Baltic Shield toward the passive margin of Baltica in pre-Ediacaran time. At one point within the Ediacaran succession, it shifted by 180 degrees due to the newly formed Timanian orogen. This orogen formed in north-eastern Baltica during the late Neoproterozoic. It caused a change in source area due to the formation of the Timanian foreland basin to the east of Digermulen Peninsula. Extensive field and laboratory work by the Digermulen Early Life Research Group, with funding from the Research Council of Norway, allows for the first time a detailed analysis of sediment supply and to test current palaeotectonic models based on a multi-method provenance approach on Neoproterozoic and Cambrian mudrocks and sandstones of the Digermulen Peninsula. The methods include, amongst others, thin-section petrography, bulk-rock geochemistry (XRF, ICP-MS), bulk-rock mineralogy (XRD), conventional heavy mineral analysis, single-grain geochemistry (EMP) and zircon U-Pb geochronology. We present and discuss the first results to decipher the sediment sources and to track changes of sediment supply through this critical time interval of Earth’s history.
|
|
| 475. |
- He, Peng
(författare)
-
Iodine Isotopes and their Species in Surface Water from the North Sea to the Northeastern Atlantic Ocean
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Huge amounts of anthropogenic 129I have been and still are released to the environment through liquid and gaseous discharges from the nuclear fuel reprocessing facilities worldwide and in particular the ones in Europe. Most of this 129I signal has been accumulated in the marine environment which plays a major role in the iodine natural pool. In this thesis, an overview of available 129I concentrations in waters of the oceans and marginal seas together with new data about 129I and 127I spatial distribution in surface seawater along a transect between the North Sea and the northeastern Atlantic Ocean are presented. After comprehensive chemical separation, the concentrations of iodine isotopes (127I and 129I) and their species (iodide and iodate) were analysed using accelerator mass spectrometry and inductively-coupled plasma mass spectrometry. The results show that, generally, changes in the 127I and 127I-/127IO3- are comparable to data from other marine waters which are related to natural distribution patterns. A considerable variation of 129I along the transect is observed with the highest values occurring in the eastern English Channel and relatively low values obtained in the northeastern Atlantic Ocean. Inventory estimations of 129I in the North Sea and the English Channel are 147 kg and 78 kg, respectively, where more than 90% resides in the Southern Bight and the eastern English Channel. Iodate is the dominant iodine species for both 127I and 129I in most seawater samples from the North Sea to the Atlantic Ocean. 129I species variability suggests a slow process of 129I- oxidation in the open sea. It takes at least 10 years for the 129I-/129IO3- pair to reach their natural equilibrium as the water is transported from the English Channel. The results suggest a main transport of 129I from the western English Channel via the Biscay Bay into the northeastern Atlantic Ocean. Further, high 129I/127I and distinctive 129I-/129IO3- values south of 40°N indicate possible contribution of 129I through Mediterranean Outflow Water. The environmental radioactive impact of 129I and possible applications in ecosystem studies are also discussed.
|
|
| 476. |
- Chierici, Melissa, 1968
(författare)
-
Carbon dioxide in the Arctic Ocean
- 2009
-
Ingår i: Japan Swedish Scientific Association workshop, Japan.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Large areas of the Arctic shelves are largely unknown with regard to the carbon dioxide system and the processes affecting the air/sea CO2 flux. This is mainly due to sparse information and lack of data as a result of large logistical challenges to conduct measurement programs which are related to the ice cover and harsh conditions in the polar oceans. Lack of information is of great concern since predictions and observations show that the polar areas are the most vulnerable region for a climate change such as a warming. Moreover, the Arctic Ocean is also predicted to be the first to become affected by an increase in ocean CO2 such as ocean acidification. However, there are large uncertainties about the direction and magnitude of the feedback processes involved in the marine system and as well as its coupling with atmospheric forcing. Large efforts in measurement programs have to be performed to be able to gain insight and understanding of the processes governing the CO2 system. One major measuring effort was performed during summer 2005 where the first continuous surface water measurements of fugacity of CO2 (fCO2sw), was performed onboard the IB Oden along the Northwest Passage from Cape Farwell (S. Greenland) to the Chukchi Sea. CO2 system parameters were measured with the aim to investigate the importance of sea ice and river runoff on the spatial variability of fCO2 and the saturation state of calcium carbonate (Ω). The variability in these parameters are related to natural occurring features such as freshwater content, sea ice, biological processes and physical upwelling. This study highlights the value of using high-frequency measurements to gain increased insight into the variable and complex conditions, encountered on the shelves in the Arctic Ocean.
|
|
| 477. |
|
|
| 478. |
|
|
| 479. |
|
|
| 480. |
- Johansson, John, 1982
(författare)
-
Optical remote sensing of industrial gas emission fluxes
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mobile optical remote sensing techniques offer promising possibilities to quantify and geographically attribute local industrial gaseous emissions to the atmosphere. Studies have shown that such emissions are often poorly understood, underestimated, and thereby not properly accounted for in emission inventories and regional atmospheric chemistry models, especially for emissions of VOCs. A better understanding and quantification of industrial VOC emissions is crucial for combating ground-level ozone, a serious problem facing most of the world's larger urban areas.This thesis presents results from a number of measurement campaigns primarily conducted in the area around Houston, Texas, USA, which has one of the world's largest concentrations of oil, gas and petrochemical industries. In the campaigns, the two flux measurement methods Solar Occultation Flux (SOF) and Mobile DOAS were used to quantify emissions of VOCs (alkanes and alkenes), SO2, NO2, and formaldehyde (HCHO) from the largest industrial conglomerates in the area.Measured emissions are compared to industry estimates reported to emission inventories, showing discrepancies of up to an order of magnitude for VOCs but not for SO2 and NO2. Emission factor models are used to estimate effects on VOC emissions of unrepresentative meteorological conditions during the measurement campaigns. These effects are determined to be too small to explain the discrepancies between measurements and reported emissions seen for VOCs.A plume chemistry model is applied to a number of cases where formaldehyde were detected together with significant amounts of alkenes in order to assess whether the formaldehyde could be explained as a secondary pollutant from the oxidation of alkenes. The results of the modeling shows that secondary emissions can only explain a small fraction of the measured formaldehyde flux in most cases, suggesting that most of the formaldehyde emissions measured from local sources were primary emissions. Secondary emissions are, however, still believed to be the largest source of formaldehyde further downwind from sources.Mobile multi-axis DOAS measurements of absolute vertical columns of NO2 and HCHO were performed in the Houston Ship Channel as a part of the 2013 NASA DISCOVER-AQ campaign in Houston. An improved methodology for deriving the vertical columns from the measured slant columns is suggested and used. The measurements are compared to several other measurement methods employed in the campaign and a significant level of agreement is found.
|
|
