| 1. |
- Blösch, Günter, et al.
(författare)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Tidskriftsartikel (refereegranskat)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 3. |
- Rich, Rebecca L., et al.
(författare)
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A global benchmark study using affinity-based biosensors
- 2009
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Ingår i: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 386:2, s. 194-216
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Tidskriftsartikel (refereegranskat)abstract
- To explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used.
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| 5. |
- Artman, Henrik, 1968-, et al.
(författare)
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Effektiv miljötillsyn : slutrapport
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Målsättningen har varit att ta fram ny kunskap inom miljötillsynen och därigenom uppnå en effektivare miljötillsyn samt att få in nya vetenskapliga perspektiv på miljötillsyn.I rapporten studeras metoder för inspektioner och det kommunikativa samspelet mellan inspektören och företrädare för den verksamhet som inspekteras, hur den institutionella ramen för inspektionsprocessen fungerar samt visar på möjligheter att mäta effekterna av inspektioner och tillsyn.Naturvårdsverket kommer att ha resultatet som ett kunskapsunderlag i fortsatt arbete med tillsynsvägledning och utveckling av hur tillsyn och tillsynsvägledning kan följas upp och utvärderas.
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| 6. |
- Beermann, Niclas, et al.
(författare)
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Photoelectrochemical studies of oriented nanorod thin films of hematite
- 2000
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Ingår i: JOURNAL OF THE ELECTROCHEMICAL SOCIETY. - : ELECTROCHEMICAL SOC INC. - 0013-4651. ; 147:7, s. 2456-2461
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Tidskriftsartikel (refereegranskat)abstract
- Thin films consisting of nanorods of hematite (alpha-Fe2O3) with controlled orientation onto transparent conductive glass substrates have been tested as photoelectrochemical cells. These films allow a more efficient transport and collection of photogenera
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| 7. |
- Ding, Bangfu, et al.
(författare)
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Oxygen Vacancy Effect on Photoluminescence Properties of Self-Activated Yttrium Tungstate
- 2014
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:44, s. 25633-25642
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Tidskriftsartikel (refereegranskat)abstract
- A series of single-phase yttrium tungstate powders were synthesized through solid-state reaction under air or argon atmosphere. All powders showed broad band emission in the visible light region, and the argon-calcined samples presented strong near-infrared luminescence. Moreover, the long-wave excitation bands peaking at 340, 378, 380, 490, and 523 nm depended critically on the calcination atmosphere and temperature. The emergence of these new excitation bands was ascribed to different oxygen vacancy concentrations with the analysis of the first-principle calculation, Raman and X-ray absorption fine structure spectra. The oxygen vacancies caused the reduction of the average coordination number of tungsten, and the position of the localized energy band changed with the oxygen vacancy concentration. Finally, a schematic photoluminescence excitation model was proposed via anion and cation charge transfer. The obtained results promise to be very useful in interpreting self-activated tungstate luminescence mechanism. They can also serve as guide line for tuning the luminescence performance of yttrium tungstate and related materials.
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| 8. |
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Figures of Southeast Asian Modernity
- 2013. - 1
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- The idea of capturing recent transformations of Southeast Asia through vignettes about familiar yet idiosyncratic individuals is brilliant. The everyday experiences and aspirations of people trying to make sense of their lives and dreams convey a complex and often surprising view of contemporary cross-currents, upheavals, anxieties, and struggles in a volatile region. This volume offers a great way for students to understand and empathize with ordinary people and nations in rapid motion.
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| 9. |
- Fredin, Kristofer, et al.
(författare)
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Effect on Cell Efficiency following Thermal Degradation of Dye-Sensitized Mesoporous Electrodes Using N719 and D5 Sensitizers
- 2009
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:43, s. 18902-18906
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Tidskriftsartikel (refereegranskat)abstract
- This work examines the comparative durability of two common dyes at temperatures that may be experienced during fabrication of dye-sensitized solar cells (DSCs) such as through the application of thermoplastics for encapsulation or the use of a molten solid-state hole conductor. Dye-sensitized electrodes were heated in an atmosphere of air or nitrogen and thereafter used as working electrodes in DSCs. Electrodes sensitized with N719 appeared more sensitive to thermal degradation than electrodes sensitized with D5, although absorbance measurements suggest similar first-order degradation rates for the two dyes. Intensity modulated photovoltage spectroscopy and intensity modulated photocurrent spectroscopy were used to measure the effect of heating on electron lifetime and transport. It was found that the electron diffusion length may.. be as low as 10% for heated samples, compared to that of the unheated counterpart, and therefore, we assess recombination as an additional efficiency limiting process in our experiments.
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| 13. |
- Greijer, Helena, et al.
(författare)
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Environmental aspects of electricity generation from a nanocrystalline dye-sensitized solar cell system
- 2001
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Ingår i: Renewable Energy. ; 23, s. 27-39
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Tidskriftsartikel (refereegranskat)abstract
- A Life Cycle Assessment, LCA, of a nanocrystalline dye sensitized solar cell (ncDSC) system has been performed, according to the ISO14040 standard. In brief, LCA is a tool to analyse the total environmental impact of a product or system from cradle to grave. Six different weighing methods were used to rank and select the significant environmental aspects to study further. The most significant environmental aspects according to the weighing methods are emission of sulphur dioxide and carbon dioxide. Carbon dioxide emission was selected as the environmental indicator depending on the growing attention on the global warming effect. In an environmental comparison of electricity generation from a ncDSC system and a natural gas/combined cycle power plant, the gas power plant would result in 450 g CO2/kWh and the ncDSC system in between 19–47 g CO2/kWh. The latter can be compared with 42 g CO2/kWh, according to van Brummelen et al. “Life Cycle Assessment of Roof Integrated Solar Cell Systems, (Report: Department of Science, Technology and Society, Utrecht University, The Netherlands, 1994)” for another thin film solar cell system made of amorphous silicon. The most significant activity/component contributing to environmental impact over the life cycle of the ncDSC system is the process energy for producing the solar cell module. Secondly comes the components; glass substrate, frame and junction box. The main improvement from an environmental point of view of the current technology would be an increase in the conversion efficiency from solar radiation to electricity generation and still use low energy demanding production technologies. Also the amount of material in the solar cell system should be minimised and designed to maximise recycling.
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| 17. |
- He, JJ, et al.
(författare)
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Dye-sensitized nanostructured p-type nickel oxide film as a photocathode for a solar cell
- 1999
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Ingår i: JOURNAL OF PHYSICAL CHEMISTRY B. - : AMER CHEMICAL SOC. - 1089-5647. ; 103:42, s. 8940-8943
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured NiO film was prepared by depositing nickel hydroxide slurry on conducting glass and sintering at 500 degrees C to a thickness of about 1 mu m. The photocurrent-voltage (IV) characteristics of the plain nanostructured NiO electrode recorded
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| 20. |
- Hinkley, James T., et al.
(författare)
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Prospects for solar only operation of the hybrid sulphur cycle for hydrogen production
- 2011
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 36:18, s. 11596-11603
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Tidskriftsartikel (refereegranskat)abstract
- The hybrid sulphur process is one of the most promising thermochemical water splitting cycles for large scale hydrogen production. While the process includes an electrolysis step, the use of sulphur dioxide in the electrolyser significantly reduces the electrical demand compared to conventional alkaline electrolysis. Solar operation of the cycle with zero emissions is possible if the electricity for the electrolyser and the high temperature thermal energy to complete the cycle are provided by solar technologies. This paper explores the possible use of photovoltaics (PV) to supply the electrical demand and examines a number of configurations. Production costs are determined for several scenarios and compared with base cases using conventional technologies. The hybrid sulphur cycle has promise in the medium term as a viable zero carbon production process if PV power is used to supply the electrolyser. However, the viability of this process is dependent on a market for hydrogen and a significant reduction in PV costs to around $1/W(p).
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| 21. |
- Johansson, Malin B., et al.
(författare)
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The Importance of Oxygen Vacancies in Nanocrystalline WO3−x ThinFilms Prepared by DC Magnetron Sputtering for Achieving High Photoelectrochemical Efficiency
- 2017
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 121:13, s. 7412-7420
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Tidskriftsartikel (refereegranskat)abstract
- The photoelectrochemical properties of tungsten oxide thinfilms with different stoichiometry (WO3−x) and thickness were investigated.The films were sputtered in O2/Ar gas (ratio 0.43) on glass substrates coatedwith fluorine-doped tin dioxide at two sputter pressures, Ptot = 10 and 30mTorr, yielding O/W ratios of the films, averaged over three samples, of 2.995and 2.999 (x ∼ 0.005 and x ∼ 0.001), respectively. The films were characterizedby X-ray diffraction, scanning electron microscopy, and spectrophotometry.The 10 mTorr samples showed large absorption in the near-infrared (NIR)range, whereas the 30 mTorr samples had a small absorption in this region. Theconcentration of oxygen vacancy band gap states was estimated from cyclicvoltammetry and was found to correlate with the optical absorption in the NIRregion. The incident photon to current efficiency for illumination from theelectrolyte side (IPCEEE) and substrate electrode side (IPCESE) showed higherefficiency for the more stoichiometric films, indicating that oxygen vacancies in the band gap act as recombination centers.Surprisingly high values of IPCEEE and IPCESE were found, and it was concluded that efficient charge separation and transporttake place almost throughout the entire film even for film electrodes as thick as 2 μm. Analysis of the spectral distribution of thephotoresponse (action spectra) using an extended Gärtner−Butler model to calculate the IPCE for front-side and back-sideillumination was performed and showed that the diffusion length is large, of the order of the depletion layer thickness.
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| 25. |
- Larsson, Ted, et al.
(författare)
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Electron transfer between cellobiose dehydrogenase and graphite electrodes
- 1996
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 331:3, s. 207-215
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Tidskriftsartikel (refereegranskat)abstract
- Electron transfer between the enzyme cellobiose dehydrogenase (CDH) and a flavin adenine dinucleotide (FAD) containing a catalytic active fragment of CDH (FAD-fragment) and a graphite electrode, respectively, was established. The current response in the presence of the enzyme substrate for graphite electrodes with CDH or the FAD-fragment adsorbed on the freshly polished graphite surface were compared with that of electrodes where CDH or the FAD-fragment were crosslinked in a redox polymer at the electrode surface. The initial slope, dj/d[S](S=0), where j is the current density and [S](S=0) the zero substrate concentration, was taken as a measure of the substrate response. For the electrodes with enzymes adsorbed directly on the surface, dj/d[S](S=0), was a factor of 3 lower than for electrodes prepared with the polymer mixture. The redox polymer based electrodes, with CDH and with FAD-fragment, both showed a high and close to equal substrate response. In contrast the surface adsorbed CDH gave a much higher substrate response than the FAD-fragment.
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