| 1. |
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| 2. |
- Hallquist, Åsa M., et al.
(författare)
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Particle and gaseous emissions from individual diesel and CNG buses
- 2013
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:10, s. 5337-5350
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Tidskriftsartikel (refereegranskat)abstract
- In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III–V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel−1. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)−1 and for the CNG buses 41 ± 26 g (kg fuel)−1. An anti-relationship between EFNOx and EFPM was observed especially for buses with no DPF, and there was a positive relationship between EFPM and EFCO.
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| 3. |
- Hunsicker, Mary E., et al.
(författare)
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Functional responses and scaling in predator-prey interactions of marine fishes : contemporary issues and emerging concepts
- 2011
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Ingår i: Ecology Letters. - : Wiley-Blackwell. - 1461-023X .- 1461-0248. ; 14:12, s. 1288-1299
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Forskningsöversikt (refereegranskat)abstract
- Predatorprey interactions are a primary structuring force vital to the resilience of marine communities and sustainability of the worlds oceans. Human influences on marine ecosystems mediate changes in species interactions. This generality is evinced by the cascading effects of overharvesting top predators on the structure and function of marine ecosystems. It follows that ecological forecasting, ecosystem management, and marine spatial planning require a better understanding of food web relationships. Characterising and scaling predatorprey interactions for use in tactical and strategic tools (i.e. multi-species management and ecosystem models) are paramount in this effort. Here, we explore what issues are involved and must be considered to advance the use of predatorprey theory in the context of marine fisheries science. We address pertinent contemporary ecological issues including (1) the approaches and complexities of evaluating predator responses in marine systems; (2) the scaling up of predatorprey interactions to the population, community, and ecosystem level; (3) the role of predatorprey theory in contemporary fisheries and ecosystem modelling approaches; and (4) directions for the future. Our intent is to point out needed research directions that will improve our understanding of predatorprey interactions in the context of the sustainable marine fisheries and ecosystem management.
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| 4. |
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| 5. |
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| 6. |
- Karlsson, Christoffer, 1986-, et al.
(författare)
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Kinetics of conducting polymers with side chain quinone units
- 2013
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Konferensbidrag (refereegranskat)abstract
- Quinones have been suggested as active material in organic lithium ion battery (LIB) cathodes. They are expected to have higher specific capacities and to be cheaper and more environmentally friendly than the inorganic lithium intercalation compounds used in LIBs today. However, quinone compounds suggested for this purpose often suffer from slow kinetics and low cyclability due to dissolution. In this work, conducting polymers containing pending quinone moieties were synthesized. Immobilizing the redox active quinone units on a conducting polymer matrix decreases both resistance and solubility, which improves the speed and the cyclability of the system, while maintaining a high specific capacity. The two-electron redox reaction of the quinone units in these polymers yields a theoretical capacity of ~300 mAh/g. The polymers were studied electrochemically and spectroscopically to elucidate the kinetics of the polymer charging and the redox cycling of the quinone units.
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| 8. |
- Lu, Guo-Wei, 1976, et al.
(författare)
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40-Gbaud 16-QAM transmitter using tandem IQ modulators with binary driving electronic signals
- 2010
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 18:22, s. 23062-23069
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Tidskriftsartikel (refereegranskat)abstract
- We propose a novel 16-quadrature amplitude modulation (QAM) transmitter based on two cascaded IQ modulators driven by four separate binary electrical signals. The proposed 16-QAM transmitter features scalable configuration and stable performance with simple bias-control. Generation of 16-QAM signals at 40 Gbaud is experimentally demonstrated for the first time and visualized with a high speed constellation analyzer. The proposed modulator is also compared to two other schemes. We investigate the modulator bandwidth requirements and tolerance to accumulated chromatic dispersion through numerical simulations, and the minimum theoretical insertion attenuation is calculated analytically.
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| 9. |
- Malm, Johan, et al.
(författare)
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Developments in biobanking workflow standardization providing sample integrity and stability
- 2013
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Ingår i: Journal of Proteomics. - : Elsevier BV. - 1874-3919 .- 1876-7737. ; 95:SI, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- Recommendations and outlines for standardization in biobanking processes are presented by a research team with long-term experience in clinical studies. These processes have important bearing on the use of samples in developing assays. These measurements are useful to document states of health and disease that are beneficial for academic research, commercial healthcare, drug development industry and government regulating agencies. There is a need for increasing awareness within proteomic and genomic communities regarding the basic concepts of collecting, storing and utilizing clinical samples. Quality control and sample suitability for analysis need to be documented and validated to ensure data integrity and establish contexts for interpretation of results. Standardized methods in proteomics and genomics are required to be practiced throughout the community allowing datasets to be comparable and shared for analysis. For example, sample processing of thousands of clinical samples, performed in 384 high-density sample tube systems in a fully automated workflow, preserves sample content and is presented showing validation criteria. Large studies will be accompanied by biological and molecular information with corresponding clinical records from patients and healthy donors. These developments position biobanks of human patient samples as an increasingly recognized major asset in disease research, future drug development and within patient care. Biological significance: The current manuscript is of major relevance to the proteomic and genomic fields, as it outlines the standardization aspects of biobanking and the requirements that are needed to run future clinical studies that will benefit the patients where OMICS science will play a major role. A global view of the field is given where best practice and conventional acceptances are presented along with ongoing large-scale biobanking projects. The authors represent broadly stakeholders that cover the academic, pharma, biotech and healthcare fields with extensive experience and deliveries. This contribution will be a milestone paper to the proteomic and genomic scientists to present data in the future that will have impact to the life science area.This article is part of a Special Issue entitled: Standardization and Quality Control in Proteomics.
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| 10. |
- Malm, Johan, et al.
(författare)
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Stardardization Developments for Large Scale Biobanks in Smoking Related Diseases - A Model System for Blood Sample Processing and Storage
- 2013
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Ingår i: Translational Respiratory Medicine. - : Springer Science and Business Media LLC. - 2213-0802. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Biobank samples stored in biobanks give researchers and respiratory healthcare institutions access to datasets of analytes valuable for both diagnostic and research practices. The usefulness of these samples in clinical decision-making is highly dependent on their quality and integrity. New procedures that better preserve sample integrity and reduce degradation are being developed to meet the needs of both present and future biobanking. Hereby we present an automatic sample workflow scheme that is designed to handle high numbers of blood samples. Blood fractions are aliquoted, heat sealed using novel technology, and stored in 384 tube high-density sample arrays. The newly developed 384 biobank rack system is especially suited for preserving identical small aliquots. This technology development allows rapid access to a given sample in the frozen archive while maintaining individual sample integrity with sample tube confinement and quality management. We provide data on robotic processing of clinical samples at -80°C, following initial processing, analysis and shipping between laboratories throughout Europe. Subsequent to unpacking, re-sorting, and storage at these sites, the samples have been returned for analysis. Biomarker analysis of 13 common tests in the clinical chemistry unit of the hospital provides evidence of qualitative and stable logistics using the 384-sample tube system.
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| 11. |
- Nilsson, C. L., et al.
(författare)
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Chromosome 19 Annotations with Disease Speciation: A First Report from the Global Research Consortium
- 2013
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 12:1, s. 134-149
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Tidskriftsartikel (refereegranskat)abstract
- A first research development progress report of the Chromosome 19 Consortium with members from Sweden, Norway, Spain, United States, China and India, a part of the Chromosome-centric Human Proteome Project (C-HPP) global initiative, is presented (http://www.c-hpp.org). From the chromosome 19 peptide-targeted library constituting 6159 peptides, a pilot study was conducted using a subset with 125 isotope-labeled peptides. We applied an annotation strategy with triple quadrupole, ESI-Qtrap, and MALDI mass spectrometry platforms, comparing the quality of data within and in between these instrumental set-ups. LC–MS conditions were outlined by multiplex assay developments, followed by MRM assay developments. SRM was applied to biobank samples, quantifying kallikrein 3 (prostate specific antigen) in plasma from prostate cancer patients. The antibody production has been initiated for more than 1200 genes from the entire chromosome 19, and the progress developments are presented. We developed a dedicated transcript microarray to serve as the mRNA identifier by screening cancer cell lines. NAPPA protein arrays were built to align with the transcript data with the Chromosome 19 NAPPA chip, dedicated to 90 proteins, as the first development delivery. We have introduced an IT-infrastructure utilizing a LIMS system that serves as the key interface for the research teams to share and explore data generated within the project. The cross-site data repository will form the basis for sample processing, including biological samples as well as patient samples from national Biobanks.
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| 12. |
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| 13. |
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| 14. |
- Nyström, Gustav, et al.
(författare)
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Long cycle life nanocellulose polypyrrole electrodes
- 2011
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Ingår i: Materials Research Society Symposium Proceedings. - : Springer Science and Business Media LLC. - 0272-9172 .- 1946-4274. ; 1312, s. 415-420
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Tidskriftsartikel (refereegranskat)abstract
- A polypyrrole (PPy) nanocellulose composite was shown to cycle well over 3000 cycles in 2.0 M NaCl electrolyte when used as the active material for both electrodes in an energy storage device. SEM micrographs show a highly porous nature of the conductive paper material and electrochemical charge-discharge measurements, as well as external electrode potential monitoring, confirm the good cycling behavior of the material.
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| 15. |
- Olsson, Henrik, et al.
(författare)
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Activation Barriers Provide Insight into the Mechanism of Self-Discharge in Polypyrrole
- 2014
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:51, s. 29643-29649
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Tidskriftsartikel (refereegranskat)abstract
- Conducting polymers are envisioned to play a significant role in the development of organic matter based electrical energy conversion and storage systems. However, successful utilization of conducting polymers relies on a fundamental understanding of their inherent possibilities and limitations. In this report we studied the temperature dependence of the self-discharge in polypyrrole and show that the rate of self-discharge is kinetically controlled by a polymer intrinsic endergonic electron transfer reaction forming a reactive intermediate. We further show that this intermediate is intimately linked to a process known as overoxidation. This process is general for most, if not all, p-doped conducting polymers irrespective of medium. The results herein are therefore expected to significantly impact the development of future energy storage systems with conducting polymer based components.
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| 16. |
- Olsson, Henrik, et al.
(författare)
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Cycling stability and self-protective properties of a paper-based polypyrrole energy storage device
- 2011
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Ingår i: Electrochemistry communications. - : Elsevier BV. - 1388-2481 .- 1873-1902. ; 13:8, s. 869-871
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Tidskriftsartikel (refereegranskat)abstract
- A composite consisting of polypyrrole and cellulose from the Cladophora sp. green algae is shown to exhibit excellent cycling stability when used as the electrodes in an aqueous symmetric supercapacitor device. The capacitance of the device, which was 32.4 F g− 1, only decreased by 0.7% during 4000 galvanostatic cycles employing a current of 10 mA and potential cut-off limits of 0 and 0.8 V. No change in the electrode material's morphology could be seen when comparing cycled and pristine materials with scanning electron microscopy. Furthermore, no significant loss in capacitance was observed even when charging the device to 1.8 V. Measurements of the electrode potentials versus a common reference show that this effect was due to a device intrinsic self-protective mechanism which prevented degradation of the polypyrrole.
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| 17. |
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| 18. |
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| 19. |
- Olsson, Henrik, et al.
(författare)
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Influence of the cellulose substrate on the electrochemical properties of paper-based polypyrrole electrode materials
- 2012
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 47:13, s. 5317-5325
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the cellulose substrate on the electrochemical performance of supercapacitor electrode materials made of polypyrrole (PPy) and cellulose is investigated. Composites were synthesized by chemical polymerization of pyrrole on dispersed fibers of cellulose from Cladophora algae and dispersed wood cellulose-based commercial filter papers, respectively, as well as on Cladophora cellulose and filter paper sheets. The resulting composites, which were characterized using scanning electron microscopy, cyclic voltammetry, and elemental analysis, were found to exhibit specific charge capacities proportional to the PPy content of the composites. The highest specific capacity (i.e., 171 C/g composite or 274 C/g PPy) was obtained for composites made from dispersed Cladophora cellulose fibers. The higher specific capacities for the Cladophora cellulose composites can be explained by the fact that the Cladophora cellulose fibers were significantly thinner than the wood cellulose fibers. While the PPy was mainly situated on the surface of the Cladophora cellulose fibers, a significant part of the PPy was found to be present within the wood fibers of the filter paper-based composites. The latter can be ascribed to a higher accessibility of the aqueous pyrrole solution to the wood-based fibers as compared to the highly crystalline algae based cellulose fibers. The present results clearly show that the choice of the cellulose substrate is important when designing electrode materials for inexpensive, flexible and environmentally friendly paper-based energy storage devices.
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| 20. |
- Olsson, Henrik
(författare)
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Nanocomposites of Cellulose and Conducting Polymer for Electrical Energy Storage
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The world’s increased energy storage demand, as well as the environmental concerns related to the combustion of fossil fuels, has triggered a transition to intermittent renewable energy sources as well as to electrical and hybrid vehicles. Current day rechargeable batteries are, due to the invention and development of lithium ion batteries, technologically well positioned to answer to some of these demands. Conventional batteries, however, utilize inorganic materials of limited supply that require large amounts of energy during refining and processing. The materials also add a significant cost to the final product, making the rechargeable batteries less attractive for large scale applications. During the last decade, significant efforts have been made to find suitable organic matter based electrode materials that can replace the inorganic materials. One class of organic materials that can be used for electrical energy storage, or be included as components in organic matter based energy storage systems, is conducting polymers.The aim of this thesis was to investigate the possibilities and limitations of using the conducting polymer polypyrrole in energy storage applications. The polymer was synthesized onto cellulose extracted from the Cladophora sp. algae, and the result was a flexible composite material. Symmetrical energy storage devices constructed with the composite material were shown to exhibit a pseudocapacitive behavior. The resistance in the cells was investigated and was found to scale linearly with the separator thickness. Cells could be cycled for 4,000 cycles without significant capacitance loss and cells that were overcharged to 1.8 V cell potential, were found to be protected by a resistive potential drop. Devices were constructed as proof-of-concept and were used to power a remote control and a digital thermometer.The self-discharge in polypyrrole was studied extensively. It was found that oxygen was responsible for the oxidation of the reduced electrode, while the positive electrode self-discharged due to a faradaic reaction. Through spectroscopy and the temperature dependence of the self-discharge, it was suggested that the self-discharge of oxidized polypyrrole is linked to the degradation at high potentials, commonly referred to as overoxidation.
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| 21. |
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| 22. |
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| 23. |
- Olsson, Henrik, et al.
(författare)
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Self-discharge Reactions in Energy Storage Devices Based on Polypyrrole-cellulose Composite Electrodes
- 2014
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Ingår i: Green. - : Walter de Gruyter GmbH. - 1869-8778 .- 1869-876X. ; 4:1-6, s. 27-39
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Tidskriftsartikel (refereegranskat)abstract
- The self-discharge behavior of organic electrodes and symmetric devices for sustainable energy storage, composed of electrodes containing a thin layer of polypyrrole coated onto a high surface area cellulose matrix, has been studied for the first time using different electrode sizes and electrolytes. Experimental data from open circuit measurements of the individual electrode potentials of charged symmetrical two-electrode energy storage devices as a function of time were evaluated based on three different self-discharge models. This evaluation clearly showed that the self-discharge process of the positive electrode is governed by a previously undetected activation-controlled faradaic reaction while the self-discharge of the negative electrode is due to diffusion controlled oxidation involving oxygen dissolved in the electrolyte. Potentiostatic three-electrode measurements and spectroelectrochemical experiments also showed that protons as well as maleimide were released from positively polarized polypyrrole electrodes. These new findings clearly show that the self-discharge of the cells originate from two different types of reactions on the positive and negative electrodes and that the main contribution to the self-discharge of the cells comes from an activation controlled reaction involving the positive electrode. These results provide an improved understanding of polypyrrole based devices and also yield new possibilities for the development of stable conducting polymer system for energy storage applications.
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| 25. |
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