| 1. |
- Boman, Christoffer, et al.
(författare)
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Stove performance and emission characteristics in residential wood log and pellet combustion : Part 1: Pellet stoves
- 2011
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 25:1, s. 307-314
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Tidskriftsartikel (refereegranskat)abstract
- Stove performance, characteristics and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter and chimney draught. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NOx, organic gaseous carbon, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions and inorganic composition. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PMtot and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene and benzene and the emissions of VOC varied in the range 1.1-47 mg/MJfuel. PAH emissions (2-340 µg/MJfuel) were generally dominated by phenantrene, fluoranthene and pyrene. PMtot (15-45 mg/MJfuel) were in all cases dominated by fine particles with mass median diameters in the range 100-200 nm, peak mobility diameters of 50-85 nm and number concentrations in the range 4×1013- 3×1014 particles/MJfuel. During high load conditions the particulate matter was totally dominated by inorganic particles at 15-25 mg/MJfuel consisting of potassium, sodium, sulfur and chlorine, in the form of K2SO4, K3Na(SO4)2 and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data.
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| 2. |
- Gustafson, Anna, et al.
(författare)
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From Face to Surface : a Fragmentation Study
- 2016
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Ingår i: Seventh International Conference & Exhibition on Mass Mining : (MassMin 2016). - Sydney : The Australian Institute of Mining and Metallurgy. - 9781925100433 ; , s. 555-562
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Konferensbidrag (refereegranskat)abstract
- The underground mining process, from in-situ characteristics of the unmined rock mass to the final mill product with fully liberated minerals, consists of a chain of unit operations. Some of them influence fragmentation while fragmentation impacts others. From a production point of view, fragmentation is a key parameter for the proper functioning of many unit operations and affects total production; it influences the ability to load, haul and crush the rock later in the process. Fragmentation varies because of rock mass strength, the presence of joints, the chosen explosive, specific charge (kg/m3) and quality of drill holes. The efficiency and result of unit operations such as drilling, blasting, loading and crushing depend on the rock properties which vary throughout a mine. Generally speaking, operations are not well adapted to the actual rock properties, leading to a non-optimised flow in production. This paper presents the initial part of a project that will build knowledge on the impact of fragmentation on each step of the production chain in an underground mine. It identifies the key parameters of fragmentation which influence the overall energy consumption and productivity in a mining operation through interviews, mine visits and a literature review. In the subsequent stages of the project, a number of field tests in the case study mine will address important segments of the production process where fragmentation is a major obstacle to improvements. Optimising the entire process, rather than isolated unit operations, will lead to increased productivity, decreased amount of interruptions and lower energy consumption.
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| 3. |
- Holmberg, Hans-Christer, et al.
(författare)
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Contribution of the legs to double-poling performance in elite cross-country skiers.
- 2006
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Ingår i: Medicine and science in sports and exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 38:10, s. 1853-60
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Tidskriftsartikel (refereegranskat)abstract
- In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP.Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed.The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05).Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.
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| 4. |
- Larsson, Richard, et al.
(författare)
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A treatment of the Zeeman effect using Stokes formalism and its implementation in the Atmospheric Radiative Transfer Simulator (ARTS)
- 2014
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 133, s. 445-453
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the practical theory that was used to implement the Zeeman effect using Stokes formalism in the Atmospheric Radiative Transfer Simulator (ARTS). ARTS now treats the Zeeman effect in a general manner for several gas species for all polarizations and takes into account variations in both magnetic and atmospheric fields along a full 3D geometry. We present how Zeeman splitting affects polarization in radiative transfer simulations and find that the effect may be large in Earth settings for polarized receivers in limb observing geometry. We find that not taking a spatially varying magnetic field into account can result in absolute errors in the measurement vector of at least 10K in Earth magnetic field settings. The paper also presents qualitative tests for O2 lines against previous models (61.15GHz line) and satellite data from Odin-SMR (487.25GHz line), and the overall consistency between previous models, satellite data, and the new ARTS Zeeman module seems encouraging.
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| 5. |
- Lönnqvist, Joel, 1987-, et al.
(författare)
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Plant cover and species compositions on subarctic green roofs
- 2017
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Ingår i: 14th IWA/IAHR International Conference on Urban Drainage in Prague, Czech Republic 10-15 September 2017.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Thisstudy looked at the plant cover and species composition of green roofs in a subarctic climate. The study’s aim was to evaluate the cover of plants and moss on green roofs in northern Sweden. Data was gathered from a field survey in summer 2016 andevaluatedroof sections located on buildings in three different towns located on a latitudinal gradient.Apart from plant cover substrate depth, slope andexposure was recorded. The results showed that the average vascular plant cover was low in the two northern locations (32% and 27%) while in the southernmost location it was high (>85%).
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| 6. |
- Migdalas, Athanasios, et al.
(författare)
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A Note on Open Problems and Challenges in Optimization Theory and Algorithms
- 2018
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Ingår i: Open Problems in Optimization and Data Analysis. - Cham : Springer Publishing Company. - 9783319991429 - 9783319991412 ; , s. 1-8
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Bokkapitel (refereegranskat)abstract
- Computational and theoretical open problems in optimization, computational geometry, data science, logistics, statistics, supply chain modeling, and data analysis are examined in this book. Each contribution provides the fundamentals needed to fully comprehend the impact of individual problems. Current theoretical, algorithmic, and practical methods used to circumvent each problem are provided to stimulate a new effort towards innovative and efficient solutions. Aimed towards graduate students and researchers in mathematics, optimization, operations research, quantitative logistics, data analysis, and statistics, this book provides a broad comprehensive approach to understanding the significance of specific challenging or open problems within each discipline.
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| 7. |
- Pettersson, Esbjörn, et al.
(författare)
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Stove performance and emission characteristics in residential wood log and pellet combustion : Part 2: Wood stove
- 2011
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 25:1, s. 315-323
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Tidskriftsartikel (refereegranskat)abstract
- The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NOx, organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJfuel, while OGC varied from 210 to 3300 mg/MJfuel. Dominating VOCs were methane, followed by ethene, acetylene and benzene. Methane varied from 9 to 1600 mg/MJfuel. The non-methane volatile organic compound (NMVOC) emissions were in the range of 20-2300 mg/MJfuel. The PAHtot emissions varied from 0.8 to 220 mg/MJfuel, in most cases dominated by phenantrene, fluoranthene and pyrene. PMtot were in all cases dominated by fine particles and varied in the range 38-350 mg/MJfuel. The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200-320 nm and 220-330 nm respectively and number concentrations in the range of 1-4×1013 particles/MJfuel. Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of conditions is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies reports considerably higher emissions especially for diluted particle sampling.
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| 8. |
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| 9. |
- Wilkinson, Cathy, 1973-
(författare)
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Social-ecological resilience and planning: an interdisciplinary exploration
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite considerable expansion in the scope and function of the state with respect to environmental protection, the world’s biological diversity and ecosystem services continue to deteriorate. Finding ways to better govern human-nature relations in cities is an important part of addressing this decline. The aim of this thesis is to explore the potential of social-ecological resilience to inform urban governance in theory and practice, through a focus on strategic spatial planning. Resilience has become an increasingly important urban policy discourse and much hope is placed in its potential to improve urban governance. However, there is an acknowledged gap between social-ecological resilience as an ideal and the ability to govern towards it in practice. At the time this doctoral research commenced there had been no engagement with social-ecological resilience in the planning theory literature and minimal engagement by empirical planning research. It is to this gap the thesis contributes. Social-ecological resilience scholarship is found to offer planning theory a partly new way of understanding complex human-nature relations. This is relevant to calls by planning theorists for more attention to matters of substance, including ecological processes. With respect to practice, planners see potential for social-ecological resilience to critically inform strategic spatial planning, including through the framing of problems, tools for analysis/synthesis and governance options. There are also however, lessons for social-ecological resilience scholarship that emerge from the detailed empirical research which suggests that attention to the politics of the everyday activities of administrators, elected officials, planning officials, conservationists and citizens operating within the so-called ‘mangle of practice’ is critical to explaining the gap between the ideal of governing for urban resilience, and what happens in practice.
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| 10. |
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