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1.	Haque, Mohammad Mazharul, 1984, et al. (författare) Self-discharge and leakage current mitigation of neutral aqueous-based supercapacitor by means of liquid crystal additive 2020 Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 453 Tidskriftsartikel (refereegranskat)abstract Self-discharge is being recognized as one of the main obstacles to implementing the supercapacitor (SC) in standalone self-powered systems. Strategies for addressing this issue include the modification of electrodes, electrolytes, separators, and diverse device configurations. However, an improved self-discharge behavior is often achieved with a large compromise on other prominent figures of merit such as capacitance, energy density, or cycle life of the device. In this work, a thorough comparative electrochemical investigation of SCs containing a neutral aqueous electrolyte, 1 M Li2SO4, and with a liquid crystal (LC) additive, 2% 4-n-pentyl-4′-cyanobiphenyl (5CB) in 1 M Li2SO4, has been carried out at different states of charge. The results demonstrate that the device containing the LC additive 5CB exhibits a reduced self-discharge and leakage current without compromising the capacitive performance at different nominal voltages compared to the behavior of the device without 5CB. We suggest an explanation of the difference of the self-discharge behavior between the devices through tunability of the effective conductivity of the electrolyte composite upon applied voltages. As a result, in an open circuit condition, the device containing LC shows a slower diffusion of ions that facilitates a decreased self-discharge and leakage current.
2.	Li, Qi, 1990, et al. (författare) Finger Number and Device Performance: A Case Study of Reduced Graphene Oxide Microsupercapacitors 2021 Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 258:2 Tidskriftsartikel (refereegranskat)abstract Microsupercapacitors (MSCs) are recognized as suitable energy storage devices for the internet of things (IoTs) applications. Herein is described the work conducted to assess the areal energy and power densities of MSCs with 2, 10, 20, and 40 interdigital finger electrodes on a fixed device footprint area (the finger interspacing is fixed at 40 μm, and the finger width and length are allowed to vary to fit the footprint area). The MSCs are based on reduced graphene oxide (rGO) materials and fabricated with a spin-coating and etch method. The performance evaluation indicates a strong dependency of areal capacitance and energy density on the number of fingers, and the maximum (impedance match) power density is also influenced to a relatively large extent, whereas the average power density is not sensitive to the configuration parameters in the present evaluation settings (scan rate 20–200 mV s−1 and current density of 100 μA cm−2). For the rGO-based devices, the equivalent distributed resistance may play an important role in determining the device resistance and power-related performance.
3.	Vyas, Agin, 1992, et al. (författare) Enhanced Electrode Deposition for On-Chip Integrated Micro-Supercapacitors by Controlled Surface Roughening 2020 Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 5:10, s. 5219-5228 Tidskriftsartikel (refereegranskat)abstract On-chip micro-supercapacitors (MSCs), integrated with energy harvesters, hold substantial promise for developing self-powered wireless sensor systems. However, MSCs have conventionally been manufactured through techniques incompatible with semiconductor fabrication technology, the most significant bottleneck being the electrode deposition technique. Utilization of spin-coating for electrode deposition has shown potential to deliver several complementary metal-oxide-semiconductor (CMOS)-compatible MSCs on a silicon substrate. Yet, their limited electrochemical performance and yield over the substrate have remained challenges obstructing their subsequent integration. We report a facile surface roughening technique for improving the wafer yield and the electrochemical performance of CMOS-compatible MSCs, specifically for reduced graphene oxide as an electrode material. A 4 nm iron layer is deposited and annealed on the wafer substrate to increase the roughness of the surface. In comparison to standard nonroughened MSCs, the increase in surface roughness leads to a 78% increased electrode thickness, 21% improvement in mass retention, 57% improvement in the uniformity of the spin-coated electrodes, and a high yield of 87% working devices on a 2″ silicon substrate. Furthermore, these improvements directly translate to higher capacitive performance with enhanced rate capability, energy, and power density. This technique brings us one step closer to fully integrable CMOS-compatible MSCs in self-powered systems for on-chip wireless sensor electronics. ©
4.	Alqeeq, S. W., et al. (författare) Investigation of the homogeneity of energy conversion processes at dipolarization fronts from MMS measurements 2022 Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 29:1 Tidskriftsartikel (refereegranskat)abstract We report on six dipolarization fronts (DFs) embedded in fast earthward flows detected by the Magnetospheric Multiscale mission during a substorm event on 23 July 2017. We analyzed Ohm's law for each event and found that ions are mostly decoupled from the magnetic field by Hall fields. However, the electron pressure gradient term is also contributing to the ion decoupling and likely responsible for an electron decoupling at DF. We also analyzed the energy conversion process and found that the energy in the spacecraft frame is transferred from the electromagnetic field to the plasma (J & BULL; E > 0) ahead or at the DF, whereas it is the opposite (J & BULL; E < 0) behind the front. This reversal is mainly due to a local reversal of the cross-tail current indicating a substructure of the DF. In the fluid frame, we found that the energy is mostly transferred from the plasma to the electromagnetic field (J & BULL; E & PRIME; < 0) and should contribute to the deceleration of the fast flow. However, we show that the energy conversion process is not homogeneous at the electron scales due to electric field fluctuations likely related to lower-hybrid drift waves. Our results suggest that the role of DF in the global energy cycle of the magnetosphere still deserves more investigation. In particular, statistical studies on DF are required to be carried out with caution due to these electron scale substructures.
5.	Attaye, Ilias, et al. (författare) Protein supplementation changes gut microbial diversity and derived metabolites in subjects with type 2 diabetes 2023 Ingår i: ISCIENCE. - 2589-0042. ; 26:8 Tidskriftsartikel (refereegranskat)abstract High-protein diets are promoted for individuals with type 2 diabetes (T2D). How-ever, effects of dietary protein interventions on (gut-derived) metabolites in T2D remains understudied. We therefore performed a multi-center, randomized -controlled, isocaloric protein intervention with 151 participants following either 12-week high-protein (HP; 30Energy %, N = 78) vs. low-protein (LP; 10 Energy%, N = 73) diet. Primary objectives were dietary effects on glycemic control which were determined via glycemic excursions, continuous glucose monitors and HbA1c. Secondary objectives were impact of diet on gut microbiota composition and-derived metabolites which were determined by shotgun-metagenomics and mass spectrometry. Analyses were performed using delta changes adjusting for center, baseline, and kidney function when appropriate. This study found that a short-term 12-week isocaloric protein modulation does not affect glycemic parameters or weight in metformin-treated T2D. However, the HP diet slightly worsened kidney function, increased alpha-diversity, and production of potentially harmful microbiota-dependent metabolites, which may affect host metabolism upon prolonged exposure.
6.	Fazey, Ioan, et al. (författare) Transforming knowledge systems for life on Earth : Visions of future systems and how to get there 2020 Ingår i: Energy Research & Social Science. - : Elsevier. - 2214-6296 .- 2214-6326. ; 70 Tidskriftsartikel (refereegranskat)abstract Formalised knowledge systems, including universities and research institutes, are important for contemporary societies. They are, however, also arguably failing humanity when their impact is measured against the level of progress being made in stimulating the societal changes needed to address challenges like climate change. In this research we used a novel futures-oriented and participatory approach that asked what future envisioned knowledge systems might need to look like and how we might get there. Findings suggest that envisioned future systems will need to be much more collaborative, open, diverse, egalitarian, and able to work with values and systemic issues. They will also need to go beyond producing knowledge about our world to generating wisdom about how to act within it. To get to envisioned systems we will need to rapidly scale methodological innovations, connect innovators, and creatively accelerate learning about working with intractable challenges. We will also need to create new funding schemes, a global knowledge commons, and challenge deeply held assumptions. To genuinely be a creative force in supporting longevity of human and non-human life on our planet, the shift in knowledge systems will probably need to be at the scale of the enlightenment and speed of the scientific and technological revolution accompanying the second World War. This will require bold and strategic action from governments, scientists, civic society and sustained transformational intent.
7.	Hansson, Josef, 1991, et al. (författare) Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes 2020 Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 451 Tidskriftsartikel (refereegranskat)abstract The electrochemical capacitor (EC) is a key enabler for the miniaturized self-powered systems expected to become ubiquitous with the advent of the internet-of-things (IoT). Vertically aligned carbon nanotubes (VACNTs) on graphite holds promise as electrodes for compact and low-loss ECs. However, as with all ECs, the operating voltage is low, and miniaturization of higher voltage devices necessitates a bipolar design. In this paper, we demonstrate a bipolar EC using graphite/VACNTs electrodes fabricated using a joule heating chemical vapor deposition (CVD) setup. The constructed EC contains one layer of double-sided VACNTs on graphite as bipolar electrode. Compared to a series connection of two individual devices, the bipolar EC has 22% boost in volumetric energy density. More significant boost is envisaged for stacking more bipolar electrode layers. The energy enhancement is achieved without aggravating self-discharge (71.2% retention after 1 h), and at no sacrifice of cycling stability (96.7% over 50000 cycles) owing to uniform growth of VACNTs and thus eliminating cell imbalance problems.
8.	Haque, Mohammad Mazharul, 1984, et al. (författare) Identification of self-discharge mechanisms of ionic liquid electrolyte based supercapacitor under high-temperature operation 2021 Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 485 Tidskriftsartikel (refereegranskat)abstract Ionic liquids (ILs) are promising electrolytes for supercapacitors (SCs) aimed for high-temperature applications, where increased ionic conductivity results in superior capacitive performance compared to room temperature (RT) performance. However, an increased temperature also accelerates the self-discharge rate that adversely affects energy retention and restricts the usage of SCs in standalone applications. In this study, a detailed electrochemical investigation on the self-discharge behaviour of carbon-based SCs containing an IL, 1-Ethyl-3-methylimidazolium acetate (EMIM Ac), has been carried out in the temperature range RT - 60 °C, and the underlying self-discharge mechanisms are identified. The results reveal that at a high voltage of 1.5 V, the self-discharge is characterized by a combination of charge redistribution and diffusion at both RT and 60 °C. At 60 °C, the diffusion-controlled mechanism dominates at lower voltages over the charge redistribution effect, while at RT both mechanisms contribute to a similar extent. The observed difference in the self-discharge mechanism between RT and 60 °C is explained in terms of a decreased RC time constant (τRC) at elevated temperature, and the same conclusions are potentially applicable to other IL-containing SCs as well.
9.	Karltun, Anette, 1956-, et al. (författare) Knowledge management infrastructure to support quality improvement : A qualitative study of maternity services in four European hospitals 2020 Ingår i: Health Policy. - : Elsevier. - 0168-8510 .- 1872-6054. ; 124:2, s. 205-215 Tidskriftsartikel (refereegranskat)abstract The influence of multilevel healthcare system interactions on clinical quality improvement (QI) is still largely unexplored. Through the lens of knowledge management (KM) theory, this study explores how hospital managers can enhance the conditions for clinical QI given the specific multilevel and professional interactions in various healthcare systems.The research used an in-depth multilevel analysis in maternity departments in four purposively sampled European hospitals (Portugal, England, Norway and Sweden). The study combines analysis of macro-level policy documents and regulations with semi-structured interviews (96) and non-participant observations (193 hours) of hospital and clinical managers and clinical staff in maternity departments.There are four main conclusions: First, the unique multilevel configuration of national healthcare policy, hospital management and clinical professionals influence the development of clinical QI efforts. Second, these different configurations provide various and often insufficient support and guidance which affect professionals’ action strategies in QI efforts. Third, hospital managers’ opportunities and capabilities for developing a consistent KM infrastructure with reinforcing enabling conditions which merge national policies and guidelines with clinical reality is crucial for clinical QI. Fourth, understanding these interrelationships provides an opportunity for improvement of the KM infrastructure for hospital managers through tailored interventions.
10.	Li, Qi, 1990, et al. (författare) Explanation of anomalous rate capability enhancement by manganese oxide incorporation in carbon nanoﬁber electrodes for electrochemical capacitors 2020 Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 340 Tidskriftsartikel (refereegranskat)abstract Electrochemical capacitors (ECs) can provide ultra-long cycle life and ultra-fast energy delivery, characteristics which most battery technologies lack. Making composites out of carbon and pseudocapacitive materials is a popular strategy directed on narrowing the gap in energy density with regard to batteries. Usually, the incorporation of pseudocapacitive materials leads to a decrease in power performance compared to a pure carbon matrix, due to inferior electrical conductivity. This work, however, presents signiﬁcant improvement in rate capability demonstrated by a composite electrode containing carbon nanoﬁbers (NCNF) and manganese oxides (MnO2). The NCNF/MnO2 is prepared with a common method through the reaction with permanganate. The material has excellent performance metrics, especially a 78.2% rate capability (capacitance retention at 15 A g−1 relative to 0.5 A g−1), more than 10 times that for the NCNF carbon matrix. The exceptional enhancement can be explained by the development of micropores and surface area of NCNF, thus alleviating the “pore starvation” issue, and surface functional groups variation that enhances capacitive performance. This work highlights the importance of paying attention to the modiﬁcation of carbon substrate when investigating carbon composite electrodes e.g. carbon/MnO2 networks.
11.	Ma, Lichen, et al. (författare) Integrating virtual realities and psychotherapy : SWOT analysis on VR and MR based treatments of anxiety and stress-related disorders 2021 Ingår i: Cognitive Behaviour Therapy. - : Informa UK Limited. - 1650-6073 .- 1651-2316. ; 50:6, s. 509-526 Tidskriftsartikel (refereegranskat)abstract The use of virtual reality (VR) and mixed reality (MR) technology in clinical psychology is growing. Efficacious VR-based treatments for a variety of disorders have been developed. However, the field of technology-assisted psychotherapy is constantly changing with the advancement in technology. Factors such as interdisciplinary collaboration, consumer familiarity and adoption of VR products, and progress in clinical science all need to be taken into consideration when integrating virtual technologies into psychotherapies. We aim to present an overview of current expert opinions on the use of virtual technologies in the treatment of anxiety and stress-related disorders. An anonymous survey was distributed to a select group of researchers and clinicians, using an analytic framework known as Strengths, Weaknesses, Opportunities, and Threats (SWOT). Overall, the respondents had an optimistic outlook regarding the current use as well as future development and implementation of technology-assisted interventions. VR and MR psychotherapies offer distinct advantages that can overcome shortcomings associated with traditional therapy. The respondents acknowledged and discussed current limitations of VR and MR psychotherapies. They recommended consolidation of existing knowledge and encouraged standardisation in both theory and practice. Continued research is needed to leverage the strengths of VR and MR to develop better treatments.
12.	Merid, Simon Kebede, et al. (författare) Epigenome-wide meta-analysis of blood DNA methylation in newborns and children identifies numerous loci related to gestational age 2020 Ingår i: Genome Medicine. - Stockholm : Karolinska Institutet, Dept of Clinical Science and Education, Södersjukhuset. - 1756-994X. Tidskriftsartikel (refereegranskat)abstract Background: Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children. Methods: We performed meta-analysis of Illumina's HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section. We also explored associations of gestational age with DNA methylation measured at 4-18 years in additional pediatric cohorts. Follow-up analyses of DNA methylation and gene expression correlations were performed in cord blood. DNA methylation profiles were also explored in tissues relevant for gestational age health effects: fetal brain and lung. Results: We identified 8899 CpGs in cord blood that were associated with gestational age (range 27-42 weeks), at Bonferroni significance, P < 1.06 × 10- 7, of which 3343 were novel. These were annotated to 4966 genes. After restricting findings to at least three significant adjacent CpGs, we identified 1276 CpGs annotated to 325 genes. Results were generally consistent when analyses were restricted to term births. Cord blood findings tended not to persist into childhood and adolescence. Pathway analyses identified enrichment for biological processes critical to embryonic development. Follow-up of identified genes showed correlations between gestational age and DNA methylation levels in fetal brain and lung tissue, as well as correlation with expression levels. Conclusions: We identified numerous CpGs differentially methylated in relation to gestational age at birth that appear to reflect fetal developmental processes across tissues. These findings may contribute to understanding mechanisms linking gestational age to health effects.
13.	Rajendra Babu Kalai Arasi, Azega, 1995, et al. (författare) Durable Activated Carbon Electrodes with a Green Binder 2022 Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 259:2 Tidskriftsartikel (refereegranskat)abstract Herein, the fabrication and electrochemical performance of thick (180−280 μm) activated carbon (AC) electrodes with carbonized lignin-derived carbon fiber (LCF) inclusions are reported. Efforts are taken in fabricating robust free-standing electrodes from an environmentally friendly binder, microfibrillated cellulose (MFC), considering the biologically hazardous nature of other commonly used binders like polytetrafluoroethylene (PTFE), n-methyl-2-pyrrolidone (NMP), and polyvinylidene fluoride (PVDF). Generally, electrodes composed of MFC binder are prone to cracking upon drying, especially with higher mass loadings, which leads to nonflexibility and poor device stability. The LCF inclusions into the AC electrode with MFC binders not only increase flexibility but also contribute to better conductivity in the electrodes. The LCFs act as an intermediate layer among AC particles and serve as conductive pathways, facilitating exposure of more active surfaces to the electrolyte. A thick electrode with high mass loading of 10 mg cm−2 is achieved. The results show that by incorporating 2 wt% LCF to the AC material, the best device with 5 mg cm−2 delivers a specific capacitance of 97 F g−1, while the specific capacitance of the reference AC device without LCF is 85 F g−1.
14.	Röver, Corinna, 1987- (författare) Making Reindeer : The Negotiation of an Arctic Animal in Modern Swedish Sápmi, 1920-2020 2021 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The Arctic has long been perceived as a static, timeless place of shielded wilderness. This perception extended to the reindeer as both part of the Arctic environment and of traditional Indigenous livelihoods. Physically, the reindeer of Swedish Sápmi looks largely the same today as it did a century ago - an animal ostensibly unaltered and unchanged.Nevertheless, this thesis argues that the reindeer has undergone a number of fundamental shifts of meaning in Swedish Sápmi over the past century. The dissertation asks how the reindeer's roles and functions evolved in Swedish Sápmi from ca. 1920 to 2020 and examines how, why and by whom the reindeer has been negotiated. It explores the changing understanding of the reindeer's role in society, studies emerging idea(l)s and purposes, and considers what mark they left on the animal.This study is a history of the ideas, discourses and practices that shaped the modern reindeer. It examines ways of understanding and making reindeer. At different points in time, varying combinations of actors have sought to control, shape and re-define this Arctic animal. The meaning attached to it changed as a result, and with it reindeer-related policies. Swedish state policies towards the Sámi and reindeer husbandry have especially deeply impacted the way reindeer were understood and governed. Over the course of a century, policy efforts aimed to control the reindeer's movements, health, reproduction and death, with varying success. Discourse and associated practices generated multiple versions of the reindeer. In terms of these changing versions, the thesis conceptualizes the reindeer as a changing technology and a socially constructed resource.Five empirical chapters trace how the reindeer was negotiated, especially between the Swedish state and Sámi herders. They show how the reindeer's role and purpose has been under repeated negotiation and discuss some of these roles. Restrictive border and grazing policies made the reindeer a trespasser at the turn of the twentieth century. From the 1950s onwards, a modernist improvement project envisioned it as economic resource. In the course of such rationalization efforts, the reindeer became an object of techno-scientific interest. Improvers attempted to transform reindeer into productive, reliable meat machines. These efforts faced a severe setback when the Chernobyl nuclear accident in 1986 contaminated considerable numbers of reindeer, turning it into a toxic animal and a threatened bearer of Sámi culture. In more recent years, we find the reindeer at an intersection of consumer demand for natural foods and Sámi agency. It has become a symbol for claims to self-determination. Sámi champions of food sovereignty and land rights have started to reclaim and promote the reindeer as traditional and wholesome source of food through the Slow Food Sápmi movement.A closer look at these re-definitions reveals that the reindeer is no timeless, passive backdrop to human action. The reindeer itself has history - it is a historical animal with agency of its own, able to challenge efforts of control. Nevertheless, the different notions of the reindeer materialized into policies and ways of governing not only the reindeer but also their Indigenous herders. The (re)negotiations of what reindeer are or ought to be provide insights into the relationship between representatives of the Swedish state and of Sámi reindeer husbandry, as well as colonial legacies and persistently unequal power relations.
15.	Schulte, Tim, et al. (författare) Caprin-1 binding to the critical stress granule protein G3BP1 is influenced by pH 2023 Ingår i: Open Biology. - : The Royal Society. - 2046-2441. ; 13:5 Tidskriftsartikel (refereegranskat)abstract G3BP is the central node within stress-induced protein-RNA interaction networks known as stress granules (SGs). The SG-associated proteins Caprin-1 and USP10 bind mutually exclusively to the NTF2 domain of G3BP1, promoting and inhibiting SG formation, respectively. Herein, we present the crystal structure of G3BP1-NTF2 in complex with a Caprin-1-derived short linear motif (SLiM). Caprin-1 interacts with His-31 and His-62 within a third NTF2-binding site outside those covered by USP10, as confirmed using biochemical and biophysical-binding assays. Nano-differential scanning fluorimetry revealed reduced thermal stability of G3BP1-NTF2 at acidic pH. This destabilization was counterbalanced significantly better by bound USP10 than Caprin-1. The G3BP1/USP10 complex immunoprecipated from human U2OS cells was more resistant to acidic buffer washes than G3BP1/Caprin-1. Acidification of cellular condensates by approximately 0.5 units relative to the cytosol was detected by ratiometric fluorescence analysis of pHluorin2 fused to G3BP1. Cells expressing a Caprin-1/FGDF chimera with higher G3BP1-binding affinity had reduced Caprin-1 levels and slightly reduced condensate sizes. This unexpected finding may suggest that binding of the USP10-derived SLiM to NTF2 reduces the propensity of G3BP1 to enter condensates.
16.	Tavares, Anderson, et al. (författare) Assessing losses for point set registration 2020 Ingår i: IEEE Robotics and Automation Letters. - : Institute of Electrical and Electronics Engineers Inc.. - 2377-3766. ; 5:2, s. 3360-3367 Tidskriftsartikel (refereegranskat)abstract This letter introduces a framework for evaluation of the losses used in point set registration. In order for a loss to be useful with a local optimizer, such as e.g. Levenberg-Marquardt, or expectation maximization (EM), it must be monotonic with respect to the sought transformation. This motivates us to introduce monotonicity violation probability (MVP) curves, and use these to assess monotonicity empirically for many different local distances, such as point-to-point, point-to-plane, and plane-to-plane. We also introduce a local shape-to-shape distance, based on the Wasserstein distance of the local normal distributions. Evaluation is done on a comprehensive benchmark of terrestrial lidar scans from two publicly available datasets. It demonstrates that matching robustness can be improved significantly, by using kernel versions of local distances together with inverse density based sample weighting.
17.	Velasco, Andres, et al. (författare) Investigation of vertical carbon nanosheet growth and its potential for microsupercapacitors 2021 Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1837:1 Konferensbidrag (refereegranskat)abstract One of the biggest applications that are coming with the Internet of Things (IoT) are miniaturized sensor networks that connect wirelessly to each other and the internet. Microsupercapacitors (MSCs) are ideal to power these devices, with large cyclability and lifetime. Porous carbons are the material of choice for these devices, but their morphology and manufacturing are far from optimized. Vertically oriented graphene MSCs have shown great promise due to their high specific surface areas and conductivity. In this work, the growth of vertically aligned carbon nanosheets (CNS) on 2-inch wafers has been studied, and it has been used as active material to manufacture MSC and transmission line model (TLM) wafers. The fabricated CNS MSC devices show a capacitance of 7.4 ?F (50.7 ?F/cm2, normalized to the area of the electrodes), a five-times increase from previous results obtained by the group.
18.	Vyas, Agin, 1992, et al. (författare) Alkyl-Amino Functionalized Reduced-Graphene-Oxide–heptadecan-9-amine-Based Spin-Coated Microsupercapacitors for On-Chip Low Power Electronics 2022 Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 259:2 Tidskriftsartikel (refereegranskat)abstract With the miniaturization of microelectronics, integrated circuits can benefit from an on-chip solid-state power supply. Microsupercapacitors (MSCs), owing to their long lifetimes and complementary metal-oxide-semiconductor (CMOS) compatible fabrication, can be a potential on-chip energy storage unit. MSCs fabricated through spin coating graphene-oxide (GrO) often suffer from insufficient electrode thicknesses that lead to low energy densities. It, therefore, requires functionalizations for GrO that can improve the MSC electrode thickness and, thereby, the performance of the MSC. Thus, herein, the MSCs fabricated of alkyl-amino functionalized reduced-graphene-oxide–heptadecan-9-amine (rGO) are reported for enhanced electrode thickness, high capacitance, and lower series resistance compared with functionalized GrO-based MSCs (GO-MSCs). The functionalized rGO solves a significant issue of inadequate electrode thickness in wafer-scale MSC fabrication while achieving higher energy densities in fewer spin coatings. The rGO-MSC displays an areal capacitance of 108 μF cm−2 compared with 24 μF cm−2 for the GO-MSC while also demonstrating more than twice its power density in an integration compatible ionic liquid electrolyte 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfony)imide (EMIM-TFSI).
19.	Vyas, Agin, 1992, et al. (författare) Comparison of Thermally Grown Carbon Nanofiber-Based and Reduced Graphene Oxide-Based CMOS-Compatible Microsupercapacitors 2021 Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 258:2 Tidskriftsartikel (refereegranskat)abstract Microsupercapacitors as miniature energy storage devices require complementary metal-oxide-semiconductor (CMOS) compatible techniques for electrode deposition to be integrated in wireless sensor network sensor systems. Among several processing techniques, chemical vapor deposition (CVD) and spin coating, present in CMOS manufacturing facilities, are the two most viable processes for electrode growth and deposition, respectively. To make an argument for choosing either of these techniques to fabricate MSCs utilizable for an on-chip power supply, we need a comparative assessment of their electrochemical performance. Herein, the evaluation of MSCs with CVD-grown carbon nanofiber (CNF)-based and spin-coated reduced graphene oxide (rGO)-based electrodes is reported. The devices are compared for their capacitance, energy and power density, charge retention, characteristic frequencies, and ease of fabrication over a large sweep of scan rates, current densities, and frequencies. The rGO-based MSCs demonstrate 112 mu F cm(-2) at 100 mV s(-1) and a power density of 12.8 mW cm(-2). The CNF-based MSCs show 269.7 mu F cm(-2) and 30.8 mW cm(-2). CVD-grown CNF outperforms spin-coated rGO in capacitive storage at low frequencies, whereas the latter is better in terms of charge retention and high-frequency capacitance response.
20.	Vyas, Agin, 1992, et al. (författare) Impact of electrode geometry and thickness on planar on-chip microsupercapacitors 2020 Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 10:52, s. 31435-31441 Tidskriftsartikel (refereegranskat)abstract We report an assessment of the influence of both finger geometry and vertically-oriented carbon nanofiber lengths in planar micro-supercapacitors. Increasing the finger number leads to an up-scaling in areal power densities, which increases with scan rate. Growing the nanofibers longer, however, does not lead to a proportional growth in capacitance, proposedly related to limited ion penetration of the electrode.
21.	Vyas, Agin, 1992, et al. (författare) Spin-Coated Heterogenous Stacked Electrodes for Performance Enhancement in CMOS-Compatible On-Chip Microsupercapacitors 2022 Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 5:4, s. 4221-4231 Tidskriftsartikel (refereegranskat)abstract Integration of microsupercapacitors (MSCs) with on-chip sensors and actuators with nanoenergy harvesters can improve the lifetime of wireless sensor nodes in an Internet-of-Things (IoT) architecture. However, to be easy to integrate with such harvester technology, MSCs should be fabricated through a complementary-metal-oxide-semiconductor (CMOS) compatible technology, ubiquitous in electrode choice with the capability of heterogeneous stacking of electrodes for modulation in properties driven by application requirements. In this article, we address both these issues through fabrication of multielectrode modular, high energy density microsupercapacitors (MSC) containing reduced graphene oxide (GO), GO-heptadecane-9-amine (GO-HD9A), rGO-octadecylamine (rGO-ODA), and rGO-heptadecane-9-amine (rGO-HD9A) that stack through a scalable, CMOS compatible, high-wafer-yield spin-coating process. Furthermore, we compare the performance of the stack with individual electrode MSCs fabricated through the same process. The individual electrodes, in the presence of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfony)imide (EMIM-TFSI), demonstrate a capacitance of 38, 30, 36, and 105 μF/cm^2 at 20 mV/s^1 whereas the fabricated stack of electrodes demonstrates a high capacitance of 280 μF/cm^2 at 20 mV/s^1 while retaining and enhancing the material-dependent capacitance, charge retention, and power density.
22.	Vyas, Agin, 1992, et al. (författare) Towards Integrated Flexible Energy Harvester and Supercapacitor for Self-powered Wearable Sensors 2020 Ingår i: 2019 19TH INTERNATIONAL CONFERENCE ON MICRO AND NANOTECHNOLOGY FOR POWER GENERATION AND ENERGY CONVERSION APPLICATIONS (POWERMEMS). Konferensbidrag (refereegranskat)abstract We present the first results of a flexible energy harvester and a foldable supercapacitor to power wearable and flexible sensors. The flexible energy harvester is fabricated by using 38 mu m piezoelectric polyvinylidene difluoride (PVDF) sandwiched between carbon electrodes. Both the design and process excel in simplicity and cost-effectiveness. The flexible harvester demonstrates a power output of 2.6 mu W cm(-3) at a resonant frequency of 50 Hz with a 3dB bandwidth of about 11 Hz, which is higher than devices previously reported and similar to a commercial PZT harvester film of same size. A flexible energy storage supercapacitor (GP-SC) was fabricated using a graphite/VACNTs (vertically aligned carbon nanotubes) material as electrodes. A prototype GP-SCs has an areal capacitance of about 1.2 mF cm(-2). Finally, an integrated scheme is proposed for future work.
23.	Willstrand, Ola, et al. (författare) Toxic Gases from Fire in Electric Vehicles 2020 Rapport (övrigt vetenskapligt/konstnärligt)abstract The ongoing shift to electromobility has identified new risk areas. Fires involving electric vehicles have attracted considerable media attention and a strong concern related to burning electric vehicles containing lithium-ion batteries is the release of toxic gas. This report includes a literature review, vehicle fire tests, battery fire tests and simulations to gather and present data on gas and heat release during fire in electric vehicles. One electrical vehicle and one conventional vehicle in the full-scale fire tests were of the same model from the same manufacturer which enable a good comparison between the powertrains. Peak heat release rate and total heat release are affected by the fire scenario and vehicle model, but not significantly on the powertrain. Regarding toxic gases, hydrogen fluoride represents the largest difference between electric vehicles and conventional vehicles, but when smoke from vehicle fire is inhaled there are several acute toxic gases present regardless of the type of vehicle burning. Except hydrogen fluoride, there are also some specific metals present in the smoke that constitutes a large difference between the powertrains.

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