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- Kuzmenko, Volodymyr, 1987, et al.
(författare)
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Cellulose-derived carbon nanofibers/graphene composite electrodes for powerful compact supercapacitors
- 2017
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:73, s. 45968-45977
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we demonstrate a unique supercapacitor composite electrode material that is originated from a sustainable cellulosic precursor via simultaneous one-step carbonization/reduction of cellulose/graphene oxide mats at 800 degrees C. The resulting freestanding material consists of mechanically stable carbon nanofibrous (CNF, fiber diameter 50-500 nm) scaffolds tightly intertwined with highly conductive reduced graphene oxide (rGO) sheets with a thickness of 1-3 nm. The material is mesoporous and has electrical conductivity of 49 S cm(-1), attributed to the well-interconnected graphene layers. The electrochemical evaluation of the CNF/graphene composite electrodes in a supercapacitor device shows very promising volumetric values of capacitance, energy and power density (up to 46 F cm(-3), 1.46 W h L-1 and 1.09 kW L-1, respectively). Moreover, the composite electrodes retain an impressive 97% of the initial capacitance over 4000 cycles. With these superior properties, the produced composite electrodes should be the "looked-for" components in compact supercapacitors used for increasingly popular portable electronics and hybrid vehicles.
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| 3. |
- Calles, Olle, 1974-, et al.
(författare)
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Success of a low-sloping rack for improving downstream passage of silver eels at a hydroelectric plant
- 2013
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Ingår i: Freshwater Biology. - : John Wiley & Sons. - 0046-5070 .- 1365-2427. ; 58, s. 2168-2179
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Tidskriftsartikel (refereegranskat)abstract
- 1. The European eel (Anguilla anguilla) is a critically endangered species, and one major threat is thesurvival of silver eels migrating downstream towards the sea from lake and river rearing areas. Duringthis migration, many eels are impinged and die on intake racks, or are injured or killed whenpassing through turbines.2. Intake racks at a hydroelectric plant were modified to avoid impingement and to collect eels withoutinjury; high mortality on both racks and in turbines was previously documented. Modificationsconsisted of reducing the rack gap width from 20 to 18 mm, decreasing the rack slope from 63 to 35degrees, increasing the rack surface area by 58% and installing six openings in the rack leading totraps.3. Downstream passage conditions for silver eels at the hydroelectric plant were significantlyimproved, reducing mortality from >70% at the old steep 20 mm racks to <10% at the modified18 mm rack collection facility. No tagged eels were impinged and killed on the racks, and 80%entered the collection facility.4. Survival can probably be improved even more, as the individuals that passed the facility mostlikely escaped through holes in the traps. Moreover, injured untagged eels were still encountered atthe modified racks, illustrating the need for rehabilitative measures to be implemented at all obstaclesbetween the main eel rearing areas and the sea.
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| 4. |
- Lindskog, Carin, 1965-
(författare)
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Tensions experienced and balancing strategies used in Agile Software Development environments
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To achieve efficiency in rapidly changing environments, working methods that promote change and flexibility are needed. Thus, the Agile ways of working (i.e. Agile values, principles, and frameworks) are today the most common approach to developing software and something that is currently spreading to many other industries and organizations outside of the traditional IT sector. However, it is challenging to combine the business-driven need for predictability and planning with the Agile ways of working, e.g. changeability, self-management and step-by-step development and delivery; therefore, several tensions can arise at the team and organizational levels. Tensions can, for example, be experienced if the team members’ experiences are rooted in traditional project environments with stable processes and predefined requirements based on detailed planning. This dissertation aims to contribute to our knowledge of Agile Software Development (ASD) by examining the contradictions and tensions in ASD environments, as well as how to balance and react to these tensions. The dissertation responds to the great need for conceptual development in the field of Information Systems. The target groups are both researchers and practitioners.The research reported on in this dissertation is based on one conceptual study and two empirical studies. The studies reported on in four appended papers jointly contribute toward answering three research questions (RQs):RQ 1: What is the nature of the tensions experienced in ASD environments?RQ 2: What are the sources of the tensions experienced in ASD environments?RQ 3: What ambidextrous strategies can be used to both balance and react to the tensions found in ASD environments?This dissertation brings together concepts from academic domains of knowledge (organizational theories of [paradoxical] tensions and ambidexterity and Activity Theory derived from socio-psychological theory) in order to provide a new insight into the complexity of ASD.This dissertation contributes by discussing and visualizing how patterns of contradictions, categorized tensions and ambidextrous (i.e. the ability to manage two seemingly contradictory activities) strategies have been compiled and connected. This dissertation also contributes by describing how three models that can be used to develop the concept of “shared mental models”, which is so important to team-based learning.
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