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PST Documentation v3.2.5_231128
No full textDocumentation of PST (Place Syntax Tool) v.3.2.5PST is an open source tool for performing spatial analyses. It combines the space syntax description of the urban environment with conventional descriptions of attraction into a combined accessibility analysis tool. It is currently available as a plugin for QGIS, an open source GIS software. Earlier PST versions are also available as a plugin for the MapInfo Professional GIS software.PST is developed by KTH School of Architecture, Chalmers School of Architecture (SMoG) and Spacescape AB. Alexander St\ue5hle, Lars Marcus, Daniel Koch, Martin Fitger, Ann Legeby, Gianna Stavroulaki, Meta Berghauser Pont, Anders Karlstr\uf6m, Pablo Miranda Carranza, Tobias Nordstr\uf6m.The software was first introduced in a paper by St\ue5hle, A., Marcus, L. and Karlstr\uf6m, A., (2005), ”Place Syntax: Geographic accessibility with axial lines in GIS”, published in the proceedings of the 5th Space Syntax Symposium held in Delft, the Netherlands.PST is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. The GNU Lesser General Public License is intended to guarantee your freedom to share and change all versions of a program--to make sure it remains free software for all its users.PST is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.The application is available via: https://github.com/SMoG-Chalmers/PST/releases/tag/v3.2.5Download: pstqgis_3.2.5_2023-02-07.zipDocumentation, data and tutorials are available via KTH and Chalmers:https://www.smog.chalmers.se/psthttps://www.arch.kth.se/forskning/urban-design/software\ua0The code is released under GNU Lesser General Public License and is available at https://github.com/SMoG-Chalmers/PSTYou should have received a copy of the GNU Lesser General Public License along with PST. If not, see <http://www.gnu.org/licenses/>
A whole system model framework to predict damage in turnouts
Get PDFThis paper presents a whole system model framework that enables a holistic prediction of accumulated track damage in railway turnouts. A modular approach allows for insight into the interaction of different damage mechanisms such as rail profile change due to the plastic deformation and wear as well as track settlement. The methodology focuses on the two most critical areas of the turnout in terms of damage: switch and crossing panels. It is shown that at the beginning of the service life of the turnout the running surface of the rails in these areas change significantly due to plastic deformation, which in turn increases the dynamic impact forces from passing vehicles. These impact forces cause vertical track settlement that is most pronounced in the crossing area. Track settlement introduces additional dynamics into the system leading to self-reinforcing behaviour. It is shown that the proposed methodology can predict accumulated track damage accounting for the coupling between different damage modes such as track settlement, rail profiles plastic deformation and wear. It can therefore be used for holistic assessment of turnouts e.g. in design optimisation studies
Serum metabolites associated with wholegrain consumption using nontargeted metabolic profiling: a discovery and reproducibility study
Get PDFPurpose: To identify fasting serum metabolites associated with WG intake in a free-living population adjusted for potential confounders. Methods: We selected fasting serum samples at baseline from a subset (n = 364) of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) cohort. The samples were analyzed using nontargeted metabolomics with liquid chromatography coupled with mass spectrometry (LC–MS). Association with WG intake was investigated using both random forest followed by linear regression adjusted for age, BMI, smoking, physical activity, energy and alcohol consumption, and partial Spearman correlation adjusted for the same covariates. Features selected by any of these models were shortlisted for annotation. We then checked if we could replicate the findings in an independent subset from the same cohort (n = 200). Results: Direct associations were observed between WG intake and pipecolic acid betaine, tetradecanedioic acid, four glucuronidated alkylresorcinols (ARs), and an unknown metabolite both in discovery and replication cohorts. The associations remained significant (FDR<0.05) even after adjustment for the confounders in both cohorts. Sinapyl alcohol was positively correlated with WG intake in both cohorts after adjustment for the confounders but not in linear models in the replication cohort. Some microbial metabolites, such as indolepropionic acid, were positively correlated with WG intake in the discovery cohort, but the correlations were not replicated in the replication cohort. Conclusions: The identified associations between WG intake and the seven metabolites after adjusting for confounders in both discovery and replication cohorts suggest the potential of these metabolites as robust biomarkers of WG consumption
Acidochromic organic photovoltaic integrated device
Get PDFTremendous efforts have been devoted to boosting the power conversion efficiency (PCE) of organic solar cells (OSCs) via the introduction of cathode interlayers (CILs). However, CIL materials have limited diversity and the development of multifunctional devices is largely neglected. Herein, an acidochromic organic photovoltaic integrated device is firstly proposed by introducing an acid-sensitive stimulating-reaction organic molecule as both the CIL of OSCs and the sensor of monitoring environmental acidity. The oxazolidine unit of acidochromic molecule can form a ring-opening structure after acid treatment, resulting in the remarkable color change with the direct reflection of pH value of ecological environment. The additive-free PM6:Y6 OSCs using the acidochromic molecule as the CIL achieve an excellent PCE of above 15.29 %, which is 47 % higher than that of the control device. The PCE can even maintain above 92 % after treating CIL with various strong acids (pH = 1). Moreover, the color of acidified films and the degraded performance of acidified OSCs can be easily restored by alkaline treatment. The successful application of CIL in other highly efficient photovoltaic systems proves its good universality. This work triggers the promising application of acidochromic molecules in solar cells as CIL with the additional function of recognition of acid environment
Role of surface morphology on bed material activation during indirect gasification of wood
Get PDFOlivine and alkali-feldspar were utilized in separate campaigns in an indirect dual fluidized bed gasification campaign with woody biomass as fuel. After three days, both bed materials were reported to be active towards tar removal and exhibited oxygen-carrying abilities and had formed an ash layer consisting of an outer ash deposition layer and an inner interaction layer. X-ray microtomography analysis concluded that a preferred deposition of ash happens onto convex regions of the bed particles, which results in an increase in thickness of the ash layer over convex regions. This effect is most pronounced for the outer layer which is a product of ash deposition. The inner layer exhibits a homogeneous thickness and is probably formed by interaction of Ca from the outer layer with the particles. Transmission electron microscopy revealed the presence of Fe and Mn on the surface of the particles in a solid solution with Mg. The oxygen-carrying effect which is found for aged particles is therefore attributed to the presence of Fe and Mn on the surface of aged particles. Alkali were found on the surface of both particles which are likely contributing to the catalytic activity of the material towards tar removal
Evolution of nano-pores during annealing of technically pure molybdenum sheet produced from different sintered formats
Get PDFMolybdenum is a refractory metal with no phase transformation in the solid state and a high melting point. It is therefore an excellent structural material for various high temperature applications. Especially in this field of operation, significant creep resistance is essential. To achieve this, a microstructure with grains in the range of millimeters is desired. However, as demonstrated in the present study, the onset temperature for secondary recrystallization, which would lead to a beneficial grain size, is among other things dependent on the initial dimensions of the sintered part. One possible reason for the different microstructural evolutions is the influence of residual pores in sub-micrometer size. Sheets were thus fabricated via three different production routes employing the same initial Mo powder to exclude chemical variation as an influencing factor. The samples were investigated by in-situ small-angle X-ray scattering at a synchrotron radiation source with two different heating rates. Additionally, selected annealed samples were studied ex-situ with high energy X-rays. The apparent volume fraction of pores is compared to a volatilization model for the vaporization of typical accompanying elements and the induced thermal expansion
Resilient supply management systems in times of crisis
Get PDFPurpose: This study investigated how organizations can maintain their supply chain (SC) resilience in\ua0situations where high-impact shocks cannot be absorbed and what capabilities are needed. The article is an empirical exploration of a socio-ecological view of resilience in the SC context. Design/methodology/approach: The case under study in this article is that of M\ue9decins sans Fronti\ue8res (MSF) and MSF\u27s reconfiguration of its supply management processes in response to the supply shocks during the coronavirus disease 2019 (COVID-19) pandemic. In total, 503 internal documents and ERP extractions from six databases from late 2019 to September 2020, 43 semi-structured interviews and a 3-round policy Delphi process were used to investigate this phenomenon. Findings: The authors\u27 results show that throughout the pandemic, MSF adapted its procurement and supply processes to cope with supply shortages at both the international and local levels of the SC. This was possible due to the organization\u27s capacity to use its exploitation and exploration capabilities of the organization at the same time. Research limitations/implications: This research is based on the single in-depth case study of a medical aid organization. Further research should investigate this phenomenon in commercial companies with similar or different organizational structures. Originality/value: This study constitutes a first attempt to empirically demonstrate that the four phases of the adaptive cycle put forth in the panarchy theory constitute a suitable representation of the reconfigurations that SCs follow in response to a high-impact shock. The study also adds to the growing body of knowledge on resilience by including ambidexterity as a mechanism to achieve resilience
The role of polaronic states in the enhancement of CO oxidation by single-atom Pt/CeO2
Get PDFSingle Atom Catalysts (SACs) have shown that the miniaturization of the active site implies new phenomena like dynamic charge transfer between isolated metal atoms and the oxide. To obtain direct proof of this character is challenging, as many experimental techniques provide averaged properties or have limitations with poorly conductive materials, leaving kinetic measurements from catalytic testing as the only reliable reference. Here we present an integrated Density Functional Theory-Microkinetic model including ground and metastable states to address the reactivity of Pt1/CeO2 for CO oxidation. Our results agree with experimentally available kinetic data in the literature and show that CO oxidation activity of Pt1/CeO2 is tunable via the electronic properties of the support. Particularly, samples with higher n-doping via oxygen depletion should be better in CO oxidation, as they help maintain the active state Pt0 of the catalyst. This provides an alternative strategy for tuning the performance of low-temperature oxidations in single-atom catalysts via charge transfer control
CO2 hydrogenation to light olefins using In2O3 and SSZ-13 catalyst-Understanding the role of zeolite acidity in olefin production
No full textWith the aim to explore the effect of acidic properties of zeolites in tandem catalysts on their performance for CO2 hydrogenation, two types of SSZ-13 zeolites with similar bulk composition, but different arrangements of framework Al, were prepared. Their morphology, pore structure, distribution of framework Al, surface acid strength and density, were explored. The results showed that SSZ-13 zeolites with isolated aluminum distribution could be successfully synthesized, however, they contained structural defects. During calcination, the framework underwent dealumination, resulting in weaker Br\uf8nsted acidity and lower crystallinity. The morphologies were, however, well preserved. Compared with the SSZ-13 zeolites, synthesized conventionally, these low acidity SSZ13 zeolites with isolated aluminum were good zeolite components in bifunctional catalysts for CO2 hydrogenation to light olefins. By combining with In2O3, they exhibited better catalytic performance for light olefin production during CO2 hydrogenation at low temperatures. Na+ cation exchange was used to adjust the Br\uf8nsted acid site (BAS) density with only minor changes to the cavity structure. Comparative experiments established that the BAS density of the zeolite, rather than the framework Al distribution (BAS distribution), overwhelmingly affected catalyst stability and product selectivity. A higher acid density reduced the selectivity for light olefins, while lower acid density tended to form inert coke species leading to rapid deactivation. The ideal amount of BAS density in the bifunctional catalyst was approximately 0.25 mmol/g, which exhibited 70% selectivity for light olefins among hydrocarbons, and 74% selectivity for CO without deactivation, after 12 h reaction at 325 celcius and 10 bar
Chronic stability of a neuroprosthesis comprising multiple adjacent Utah arrays in monkeys
Get PDFObjective. Electrical stimulation of visual cortex via a neuroprosthesis induces the perception of dots of light (\u27phosphenes\u27), potentially allowing recognition of simple shapes even after decades of blindness. However, restoration of functional vision requires large numbers of electrodes, and chronic, clinical implantation of intracortical electrodes in the visual cortex has only been achieved using devices of up to 96 channels. We evaluated the efficacy and stability of a 1024-channel neuroprosthesis system in non-human primates (NHPs) over more than 3 years to assess its suitability for long-term vision restoration. Approach. We implanted 16 microelectrode arrays (Utah arrays) consisting of 8 x 8 electrodes with iridium oxide tips in the primary visual cortex (V1) and visual area 4 (V4) of two sighted macaques. We monitored the animals\u27 health and measured electrode impedances and neuronal signal quality by calculating signal-to-noise ratios of visually driven neuronal activity, peak-to-peak voltages of the waveforms of action potentials, and the number of channels with high-amplitude signals. We delivered cortical microstimulation and determined the minimum current that could be perceived, monitoring the number of channels that successfully yielded phosphenes. We also examined the influence of the implant on a visual task after 2-3 years of implantation and determined the integrity of the brain tissue with a histological analysis 3-3.5 years post-implantation. Main results. The monkeys remained healthy throughout the implantation period and the device retained its mechanical integrity and electrical conductivity. However, we observed decreasing signal quality with time, declining numbers of phosphene-evoking electrodes, decreases in electrode impedances, and impaired performance on a visual task at visual field locations corresponding to implanted cortical regions. Current thresholds increased with time in one of the two animals. The histological analysis revealed encapsulation of arrays and cortical degeneration. Scanning electron microscopy on one array revealed degradation of IrOx coating and higher impedances for electrodes with broken tips. Significance. Long-term implantation of a high-channel-count device in NHP visual cortex was accompanied by deformation of cortical tissue and decreased stimulation efficacy and signal quality over time. We conclude that improvements in device biocompatibility and/or refinement of implantation techniques are needed before future clinical use is feasible