| 1. |
- Hammar, Linus, 1979, et al.
(författare)
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Introducing ocean energy industries to a busy marine environment
- 2017
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 74, s. 178-185
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Forskningsöversikt (refereegranskat)abstract
- The immense energy potential of the oceans is being increasingly recognized the world over, at the same time the integrity of marine ecosystems is challenged by pressure from multiple human activities. For good reasons environmental licensing procedures are precautionary and new industries must declare their detrimental impacts and provide mitigation measures. New ocean energy industries target renewable energy sources thus, on a grand scale, partly mitigating climate change. However, on-site environmental impacts are yet to be established. In this review we compare ocean energy industries with a wide range of conventional, better understood, human activities and outline environmental risks and research priorities. Results show that ocean energy systems are thought to incur many pressures, some familiar and others with yet unknown effects. Particular uncertainties regard ocean thermal energy conversion (OTEC) and large fast-moving turbines. Ocean energy industries should not be considered in isolation because the significance of environmental impacts depend on the full spectra of human activities in each area. Marine spatial planning provides a platform for holistic assessments and may facilitate the establishment of ocean energy industries, as long as risk-related uncertainties are reduced.
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| 2. |
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| 3. |
- Palmquist, Anders, 1977, et al.
(författare)
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Complex geometry and integrated macro-porosity: Clinical applications of electron beam melting to fabricate bespoke bone-anchored implants
- 2023
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 156, s. 125-145
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Forskningsöversikt (refereegranskat)abstract
- The last decade has witnessed rapid advancements in manufacturing technologies for biomedical implants. Additive manufacturing (or 3D printing) has broken down major barriers in the way of producing complex 3D geometries. Electron beam melting (EBM) is one such 3D printing process applicable to metals and alloys. EBM offers build rates up to two orders of magnitude greater than comparable laser-based technologies and a high vacuum environment to prevent accumulation of trace elements. These features make EBM particularly advantageous for materials susceptible to spontaneous oxidation and nitrogen pick-up when exposed to air (e.g., titanium and titanium-based alloys). For skeletal reconstruction(s), anatomical mimickry and integrated macro-porous architecture to facilitate bone ingrowth are undoubtedly the key features of EBM manufactured implants. Using finite element modelling of physiological loading conditions, the design of a prosthesis may be further personalised. This review looks at the many unique clinical applications of EBM in skeletal repair and the ground-breaking innovations in prosthetic rehabilitation. From a simple acetabular cup to the fifth toe, from the hand-wrist complex to the shoulder, and from vertebral replacement to cranio-maxillofacial reconstruction, EBM has experienced it all. While sternocostal reconstructions might be rare, the repair of long bones using EBM manufactured implants is becoming exceedingly frequent. Despite the various merits, several challenges remain yet untackled. Nevertheless, with the capability to produce osseointegrating implants of any conceivable shape/size, and permissive of bone ingrowth and functional loading, EBM can pave the way for numerous fascinating and novel applications in skeletal repair, regeneration, and rehabilitation. Statement of significance: Electron beam melting (EBM) offers unparalleled possibilities in producing contaminant-free, complex and intricate geometries from alloys of biomedical interest, including Ti6Al4V and CoCr. We review the diverse range of clinical applications of EBM in skeletal repair, both as mass produced off-the-shelf implants and personalised, patient-specific prostheses. From replacing large volumes of disease-affected bone to complex, multi-material reconstructions, almost every part of the human skeleton has been replaced with an EBM manufactured analog to achieve macroscopic anatomical-mimickry. However, various questions regarding long-term performance of patient-specific implants remain unaddressed. Directions for further development include designing personalised implants and prostheses based on simulated loading conditions and accounting for trabecular bone microstructure with respect to physiological factors such as patient's age and disease status.
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| 4. |
- Wilson, Stephen A., et al.
(författare)
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New materials for micro-scale sensors and actuators An engineering review
- 2007
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Ingår i: Materials science & engineering. R, Reports. - : Elsevier BV. - 0927-796X .- 1879-212X. ; 56:06-jan, s. 1-129
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Forskningsöversikt (refereegranskat)abstract
- This paper provides a detailed overview of developments in transducer materials technology relating to their current and future applications in micro-scale devices. Recent advances in piezoelectric, magnetostrictive and shape-memory alloy systems are discussed and emerging transducer materials such as magnetic nanoparticles, expandable micro-spheres and conductive polymers are introduced. Materials properties, transducer mechanisms and end applications are described and the potential for integration of the materials with ancillary systems components is viewed as an essential consideration. The review concludes with a short discussion of structural polymers that are extending the range of micro-fabrication techniques available to designers and production engineers beyond the limitations of silicon fabrication technology.
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| 5. |
- Mahshid, Rasoul, et al.
(författare)
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Recent advances in development of additively manufactured thermosets and fiber reinforced thermosetting composites: Technologies, materials, and mechanical properties
- 2023
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Ingår i: Composites Part A: Applied Science and Manufacturing. - 1359-835X. ; 171
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Forskningsöversikt (refereegranskat)abstract
- Additive manufacturing (AM) has a great potential to create complex parts and systems lighter and stronger compared to traditional manufacturing operations. So far, several polymeric materials including different types of thermoset polymers and recently fiber reinforced thermosetting composites have been used in different additive manufacturing processes. Printed parts have shown an enhanced performance compared to their counterparts made by conventional techniques. This review article presents the state-of-the-art in the field of polymer-based additive manufacturing processes employed for thermoset resins, their corresponding fiber reinforced composites, main process parameters, build strategies, and their effects on the mechanical behavior of printed parts. This paper enlightens the basics of material extrusion, vat photopolymerization, and hybrid AM processes. In particular, these techniques involve Direct Ink Writing (DIW), Frontal Polymerization (FP), Reactive Extrusion (RE), In-bath print and cure (IBPC) that fall under extrusion-based AM system, and Stereolithography (SLA), Digital Light Processing (DLP) falling under vat photopolymerization AM.
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| 6. |
- Nik, Vahid, 1979, et al.
(författare)
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Towards climate resilient urban energy systems: A review
- 2021
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Ingår i: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 8:3
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Forskningsöversikt (refereegranskat)abstract
- Climate change and increased urban population are two major concerns for society. Moving towards more sustainable energy solutions in the urban context by integrating renewable energy technologies supports decarbonizing the energy sector and climate change mitigation. A successful transition also needs adequate consideration of climate change including extreme events to ensure the reliable performance of energy systems in the long run. This review provides an overview of and insight into the progress achieved in the energy sector to adapt to climate change, focusing on the climate resilience of urban energy systems. The state-of-the-art methodology to assess impacts of climate change including extreme events and uncertainties on the design and performance of energy systems is described and discussed. Climate resilience is an emerging concept that is increasingly used to represent the durability and stable performance of energy systems against extreme climate events. However, it has not yet been adequately explored and widely used, as its definition has not been clearly articulated and assessment is mostly based on qualitative aspects. This study reveals that a major limitation in the state-of-the-art is the inadequacy of climate change adaptation approaches in designing and preparing urban energy systems to satisfactorily address plausible extreme climate events. Furthermore, the complexity of the climate and energy models and the mismatch between their temporal and spatial resolutions are the major limitations in linking these models. Therefore, few studies have focused on the design and operation of urban energy infrastructure in terms of climate resilience. Considering the occurrence of extreme climate events and increasing demand for implementing climate adaptation strategies, the study highlights the importance of improving energy system models to consider future climate variations including extreme events to identify climate resilient energy transition pathways.
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| 7. |
- von Mentzer, Ula, 1995, et al.
(författare)
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Biomaterial Integration in the Joint: Pathological Considerations, Immunomodulation, and the Extracellular Matrix
- 2022
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Ingår i: Macromolecular Bioscience. - : Wiley. - 1616-5195 .- 1616-5187. ; 22:7
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Forskningsöversikt (refereegranskat)abstract
- Defects of articular joints are becoming an increasing societal burden due to a persistent increase in obesity and aging. For some patients suffering from cartilage erosion, joint replacement is the final option to regain proper motion and limit pain. Extensive research has been undertaken to identify novel strategies enabling earlier intervention to promote regeneration and cartilage healing. With the introduction of decellularized extracellular matrix (dECM), researchers have tapped into the potential for increased tissue regeneration by designing biomaterials with inherent biochemical and immunomodulatory signals. Compared to conventional and synthetic materials, dECM-based materials invoke a reduced foreign body response. It is therefore highly beneficial to understand the interplay of how these native tissue-based materials initiate a favorable remodeling process by the immune system. Yet, such an understanding also demands increasing considerations of the pathological environment and remodeling processes, especially for materials designed for early disease intervention. This knowledge will avoid rejection and help predict complications in conditions with inflammatory components such as arthritides. This review outlines general issues facing biomaterial integration and emphasizes the importance of tissue-derived macromolecular components in regulating essential homeostatic, immunological, and pathological processes to increase biomaterial integration for patients suffering from joint degenerative diseases.
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| 8. |
- Diamond, Miriam, et al.
(författare)
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Exploring the planetary boundary for chemical pollution
- 2015
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 78, s. 8-15
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Forskningsöversikt (refereegranskat)abstract
- Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if “unacceptable global change” is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social approaches to mitigate global chemical pollution that emphasize a preventative approach; coordinate pollution control and sustainability efforts; and facilitate implementation of multiple (and potentially decentralized) control efforts involving scientists, civil society, government, non-governmental organizations and international bodies.
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| 9. |
- Riva, Fabio, et al.
(författare)
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Electricity access and rural development: Review of complex socio-economic dynamics and casual diagrams for more appropriate energy modelling
- 2018
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Ingår i: Energy for Sustainable Development. - : Elsevier BV. - 2352-4669 .- 0973-0826. ; 43, s. 203-223
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Forskningsöversikt (refereegranskat)abstract
- The causal relationships between electrification and development of poor, rural communities are complex and contextual. The existing literature focuses mainly on the impact of rural electrification and electricity use on local socio-economic development, while the reverse feedbacks of various social and economic changes on electricity demand and supply have not been fully characterized. Most electricity access impact assessments assume linear, one-way effects and linear growth in electricity demand. However, the projections rarely match the reality, creating challenges for rural utilities. From a modelling perspective, the lack of attention to dynamic complexities of the electricity-development nexus prevents the appropriate modelling of electricity demand over time and, hence, informed planning for and sizing of power plants. With the goal to improve modelling of the electricity-development nexus, we undertake a comprehensive review and extensive analysis of the peer-reviewed literature on electricity access and its impact on rural socio-economic development, and vice versa. We characterize and describe the nexus between electricity access and development through graphical casual diagrams that allow us to capture, visualise and discuss the complexity and feedback loops. Based on this, we suggest guidelines for developing appropriate models able to include and simulate such complexities. Our analysis confirms that electricity use is interconnected through complex casual relations with multiple dimensions of socio-economic development, viz. income generating activities, market production and revenues, household economy, local health and population, education, and habits and social networks. The casual diagrams can be seen as a first step of the conceptualization phase of model building, which aims at describing and understanding the structure of a system. The presence of multiple uncertain parameters and complex diffusion mechanisms that describe the complex system under analysis suggests that systems-dynamic simulations can allow modelling such complex and dynamic relations, as well as dealing with the high uncertainties at stake, especially when coupled with stochastic approaches.
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| 10. |
- Komitov, Lachezar, 1944
(författare)
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Tuning the alignment of liquid crystals by means of nano-structured surfaces
- 2008
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Ingår i: Journal of the SID. - 1071-0922. ; 16:9, s. 919-925
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Forskningsöversikt (refereegranskat)abstract
- The solid-surface/liquid-crystal interactions, defining the field-free alignment of the liquid crystal in conventional liquid-crystal displays, are playing a vital role in their optical appearance and performance. Nano- scale changes in the solid-surface structure induced by light have been recently shown to affect the anchoring strength and the easy-axis direction. Fine tuning of the anchoring strength is also demonstrated by nano- structuring of the Langmuir–Blodgett monolayer employed as liquid-crystal alignment layers promoting homeotropic orientation. On the basis of nano-engineering of the surface alignment properties, two novel alignment concepts have been introduced: electrically commanded surfaces (ECS) and high-performance alignment layers (HiPAL). Nano-structured polymers related to these concepts have been designed, synthesized, and used as materials for alignment layers in LCDs. ECS materials belong to the category of active alignment materials designed to mediate switching of the liquid crystal, whereas the HiPALmaterials make possible the control of the molecular tilt angle in a broad range, from 0° to 90°, and they seem to enable the control of the anchoring strength as well. The nano-structured alignment materials are strong candidates for implementation in a new generation of advanced liquid-crystal displays and devices.
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