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Exploring Swedish urban freight stakeholders’ interests in public spaces
Get PDFUrban stakeholders have divergent interests in the use of public space in cities and should be considered in city-planning of urban freight. This paper explores Swedish urban stakeholder’s interests in the use of public space. A literature review on Urban Freight Stakeholders (UFSs) with direct impact on city-planning, and their interest’ in the use of public space was conducted and used as a theoretical foundation in a cross-case analysis of two Swedish cities. Forty-five semi-structured interviews, and forty-one answers from a multiple-choice question were used as empirical data in the evaluation of UFSs’ interests. The paper shows that interests’ of UFSs which contribute to attractive urban environment should be considered in city-planning of urban freight. In addition, policies on road safety, decoration of the city environment and pricing the use of public space in cities need to be developed at local authorities. The paper confirms property owners as UFSs with similar accessibility and service interests as local authorities in the city-planning of urban freight. The literature review of published research and a cross-case analysis of Swedish UFSs’ interests in public space in two cities provides insights for further development of research to enrich theory and city-planning of urban freight
Electrolyte recovery from spent Lithium-Ion batteries using a low temperature thermal treatment process
Get PDFElectrolyte recovery is seldomly considered in state-of-art lithium-ion battery recycling methods but rather evaporates and decomposes uncontrolled during the pre-treatment steps. However, controlled and safe removal of the electrolyte is inevitable and of high importance to the recycling industry to minimize the environmental impact of the recycling processes by preventing severe threats produced by the inflammable, toxic and hazardous components of the electrolyte. This study investigated the effects of temperature and process time of a low temperature thermal treatment process on electrolyte recovery. The process exhaust gases and recovered products were analyzed by In-Situ Fourier-transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC–MS) to determine the effectiveness of the significant process parameters. The results show that the electrolyte solvents, which are dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), were successfully recovered for 80\ua0minutes of processing time at 130\ua0\ub0C. The LiPF6 decomposition products hydrogen fluoride (HF) and phosphoryl fluoride (POF3) were detected in the exhaust gas stream and recovered as acidic solutions. Thermal treatment below 150\ua0\ub0C is a promising approach for the recovery of the electrolyte solvents prior to the metal recycling stage due to its simplicity, feasibility, and environmental benefit
Long-term mesospheric record of EPP-IE NO measured by Odin/SMR
Get PDFDue to the long lifetime of nitric oxide (NO) in darkness conditions, during polar winter, the NO produced by energetic particle precipitation (EPP) in the mesosphere and lower thermosphere (MLT) can descend, via the middle atmospheric residual circulation, to the lower mesosphere and stratosphere, where it is involved in catalytic destruction of ozone (O3). This process is known as energetic particle precipitation indirect effect (EPP-IE). There are still significant uncertainties on the estimated amount of EPP-IE NO. To improve such estimations, we measure the total winter flux of EPP-IE NO descending through three isentropic levels in the mesosphere, that is 2600 K, 3300 K and 4000 K, based on 15 years of NO nighttime observations from the Sub-Millimetre Radiometer (SMR) on board Odin satellite. At the moment, Odin/SMR is the only instrument ensuring a global coverage of mesospheric NO observations within a few days and this is the first time EPP-IE NO has been quantified using its NO data set. Moreover, such an estimate had never been calculated for the most recent winters which are included in this study. In our method we calculate the median nighttime NO inside the polar vortex during the month prior to the descent of NO-rich air; this value is assumed as a background, produced by N2O oxidation, to be subtracted from the daily median nighttime concentrations inside the vortex; the result of this subtraction is then multiplied by the area of the vortex and the descent rate to obtain the flux; finally these daily quantities and integrated to calculate the total NO flux for each winter. We thus calculated the total EPP-IE NO flux through the mentioned levels for Northern Hemisphere (NH) winters between 2006–07 and 2020–21 and for Southern Hemisphere (SH) winters between 2007 and 2012. The total winter EPP-IE NO fluxes presented in this study are consistent with the quantities presented in similar studies. NH winters 2008–09, 2012–13 and 2018–19 are the ones presenting the highest NO fluxes at all levels. They are winters characterised by sudden stratospheric warmings followed by elevated stratopause (SSW-ES) events. The measured fluxes vary between 490 and 1000 Mmol at 4000 K, 310 and 720 Mmol at 3300 K, 270 and 510 Mmol at 2600 K. All other NH and SH winters are characterised by sensibly lower values than SSW-ES winters. The fluxes from these more dynamically quiet winters vary from winter to winter following a trend similar to the one of geomagnetic activity, as indicated by the variations in Ap index. These results indicate that the variability in the total EPP-IE NO fluxes is dominated by dynamics during the SSW-ES winters, whereas during the remaining winters it is geomagnetic activity that plays a major role
Research on the durability and Sustainability of an artificial lightweight aggregate concrete made from municipal solid waste incinerator bottom ash (MSWIBA)
No full textThis study chooses to use three common cementing materials, Portland cement (OPC), ground granulated blast furnace slag (GGBFS) and fly ash (FA), as the binder for the production of three artificial lightweight coarse aggregates (ALCAs) through cold bonding with municipal solid waste incineration bottom ash (MSWIBA) in which MSWIBA accounts for 70% of the total content by volume. In this study, three ALCAs were used to replace 0%, 30%, 60%, and 100% of natural aggregates used in the production of concrete. Through capillary water absorption and rapid migration of chloride ions, the effect of the replacement amount of ALCAs on the durability of concrete was explored. Additionally, in accordance with the Material Sustainability Index (MSI), a statistical analysis of the CO2 emissions, energy consumption and cost of the concrete made of the three ALCAs was carried out. Studies have shown that ALCAs can improve the Interfacial Transition Zone (ITZ) and pore structure of concrete, thereby improving the ability of concrete to resist chloride ion penetration. In addition, the use of ALCAs can reduce the cost of concrete. Among the ALCAs used in this study, those which use GGBFS and FA as adhesives (without OPC) can improve the durability of concrete the most and reduce CO2 emissions
Fouling characteristics of microcrystalline cellulose during cross-flow microfiltration: Insights from fluid dynamic gauging and molecular dynamics simulations
Get PDFThe fouling behaviour of microcrystalline cellulose (MCC) particles on polyethersulfone (PES) membranes was investigated using fluid dynamic gauging (FDG) and molecular dynamics (MD) simulations. Experimental cross-flow microfiltration (MF) of a dilute MCC suspension at 400 mbar transmembrane pressure using 0.45 μm PES membranes revealed an estimated fouling layer thickness of 616 \ub1 5 μm for both fouled and re-fouled membranes at an applied shear stress of 37 \ub1 2 Pa. A decline in pure water flux was observed after each membrane cleaning and flushing procedure, indicating that highly resilient layers were formed close to the membrane surface. A possible explanation for the formation of resilient cellulose layers was obtained through MD simulations of the free energy profiles, which predicted deep energy minima at close interparticle separations of the cellulose–cellulose and cellulose–PES systems. The consequence of this energy minima is that attractive and repulsive forces are in balance at a specific distance between the particles, suggesting high binding energy at close interparticle distances. This implies that a certain force is needed to remove the layer or redisperse the cellulose particles. MD simulations also suggested that contributions made by repulsive hydration forces negatively influenced the adsorption of cellulose particles onto the PES membrane. These results highlight how experimental FDG measurements, when complemented with MD simulations, can provide insights into the fouling behaviour of an organic model material during cross-flow filtration
A Picture is Worth a Thousand Words: Natural Language Processing in Context
No full textModern NLP models learn language from lexical co-occurrences. While this method has allowed for significant breakthroughs, it has also exposed potential limitations of modern NLP methods. For example, NLP models are prone to hallucinate, represent a biased world view and may learn spurious correlations to solve the data instead of the task at hand. This is to some extent the consequence of training the models exclusively on text. In text, concepts are only defined by the words that accompany them and the information in text is incomplete due to reporting bias. In this work, we investigate whether additional context in the form of multimodal information can be used to improve on the representations of modern NLP models. Specifically, we consider BERT-based vision-and-language models that receive additional context from images. We hypothesize that visual training primarily should improve on the visual commonsense knowledge, i.e. obvious knowledge about visual properties, of the models. To probe for this knowledge we develop the evaluation tasks Memory Colors and Visual Property Norms. Generally, we find that the vision-and-language models considered do not outperform unimodal model counterparts. In addition to this, we find that the models switch their answer depending on prompt when evaluated for the same type of knowledge. We conclude that more work is needed on understanding and developing vision-and-language models, and that extra focus should be put on how to successfully fuse image and language processing. We also reconsider the usefulness of measuring commonsense knowledge in models that cannot represent factual knowledge
Long-term electricity supply modelling in the context of developing countries: The OSeMOSYS-LEAP soft-linking approach for Ethiopia
Get PDFLong-term power supply modelling is particularly important for developing countries in providing sustainable solutions to electricity problems. This study presents the first detailed and complete model of the Ethiopian electricity system while considering the unique features (dominance of traditional energy, informal economy, urban-rural divide, low electrification, supply shortage, etc.) and context of developing countries that is developed by soft-linking the OSeMOSYS (Open-Source energy Modelling System) and LEAP (Long-range Energy Alternatives Planning System) modelling frameworks. Better system representation and design of plausible scenarios that explore the potential pathways of the future power supply and demand evolution until 2050 is done by performing sensitivity analysis. Sector wise and technological representation of supply and end-uses at a disaggregated level, assessment of centralized grid-based means and decentralized off-grid methods for improving electricity access are the main methodological contributions. Five policy scenarios are employed to explore different possible futures and balance the long-term electricity needs and resources. The improved efficiency scenario reduces the installed capacity by 9 GW which translates into approximately 11% total discounted cost saving (USD $ 4 billion). This economic benefit has made the efficiency scenario the most desirable compared to the other scenarios. Attributed to lower investment costs and abundant resource availability, the results show that renewable technologies are more competitive and favourable
Performance and reliability analysis of an off-grid PV mini-grid system in rural tropical Africa: A case study in southern Ethiopia
Get PDFAlthough some progress has been made in recent years, ensuring universal access to electricity remains a major challenge in many countries in sub-Saharan Africa, particularly in rural areas. In light of this challenge, solar photovoltaic (PV) mini-grid systems have emerged as a promising solution for off-grid electrification. However, little is known about their actual performance and reliability when used in real-world applications. Using real-time monitored data and IEC\u27s evaluation standard, this paper examines the performance and reliability of a 375 kWp off-grid PV mini-grid system installed in a remote small town in Ethiopia. The findings showed that the mini-grid produced 1182 kWh/day of electricity compared to the estimated generation of 2214 kWh/day, a difference of 1032 kWh/day (46.6% less). In contrast, 87% of the average daily electricity generated was delivered to the load. The discrepancies can be attributed to average PV capture losses of 2.75 kWh/kWp/day and system losses of 0.40 kWh/kWp/day. The performance evaluation results revealed that the mini-grid system is performing poorly, with average on-site module efficiency (ηpc), temperature corrected performance ratio (PRcorr), capacity factor (CF) and overall system efficiency (ηsys) of 9.85%, 42%, 13%, and 8.76%, respectively. It was found that the daily PV energy output could not meet the daily demand. As a result, the load is shed off from the power supply for 13 h a day; between 17:00 and 19:00 and again between 21:00 and 08:00. The study demonstrated that accurate demand assessment and robust system sizing, taking into account the impact of local weather conditions and prospective electricity demand growth is critical to ensure high performance and reliability of off-grid PV mini-grid systems
Electrical tuning of moir\ue9 excitons in MoSe2 bilayers
No full textRecent advances in the field of vertically stacked 2D materials have revealed a rich exciton landscape. In particular, it has been demonstrated that out-of-plane electrical fields can be used to tune the spectral position of spatially separated interlayer excitons. Other studies have shown that there is a strong hybridization of exciton states, resulting from the mixing of electronic states in both layers. However, the connection between the twist-angle dependent hybridization and field-induced energy shifts has remained in the dark. Here, we investigate on a microscopic footing the interplay of electrical and twist-angle tuning of moir\ue9 excitons in MoSe2 homobilayers. We reveal distinct energy regions in PL spectra that are clearly dominated by either intralayer or interlayer excitons, or even dark excitons. Consequently, we predict twist-angle-dependent critical electrical fields at which the material is being transformed from a direct into an indirect semiconductor. Our work provides new microscopic insights into experimentally accessible knobs to significantly tune the moir\ue9 exciton physics in atomically thin nanomaterials
Identification of metabotypes in complex biological data using tensor decomposition
Get PDFDifferences in the physiological response to treatment, such as dietary intervention, has led to the development of precision approaches in nutrition and medicine to tailor treatment for improved benefits to the individual. One such approach is to identify metabotypes, i.e., groups of individuals with similar metabolic profiles and/or regulation. Metabotyping has previously been performed using e.g., principal component analysis (PCA) on matrix data. However, metabotyping methods suitable for more complex experimental designs such as repeated measures or cross-over studies are needed. We have developed a metabotyping method for tensor data, based on CANDECOMP/PARAFAC (CP) tensor decomposition. Metabotypes are inferred from CP scores using k-means clustering, and robustness is evaluated using bootstrapping of metabolites. As a proof-of-concept, we identified metabotypes from metabolomics data where 79 metabolites were analyzed in 8 time points postprandially in 17 overweight men that underwent a three-arm dietary crossover intervention. Two metabotypes were found, characterized by differences in amino acid metabolite concentration, that were differentially associated with baseline plasma creatinine (p = 0.007) and with the baseline metabolome (p = 0.004). These results suggest that CP decomposition provides a viable approach for metabotype identification directly from complex, high-dimensional data with improved biological interpretation compared to the more simplistic PCA approach. A simulation study together with results from measured data concluded that several preprocessing methods should be taken into consideration for CP-based metabotyping on complex tensor data