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Assessing the Impact of Rubberized Asphalt on Reducing Hip Fracture Risk in Elderly Populations Using Human Body Models
No full textCompared to other age groups, older adults are at more significant risk of hip fracture when they fall. In addition to the higher risk of falls for the elderly, fear of falls can reduce this population’s outdoor activity. Various preventive solutions have been proposed to reduce the risk of hip fractures ranging from wearable hip protectors to indoor flooring systems. A previously developed rubberized asphalt mixture demonstrated the potential to reduce the risk of head injury. In the current study, the capability of the rubberized asphalt sample was evaluated for the risk of hip fracture for an average elderly male and an average elderly female. A previously developed human body model was positioned in a fall configuration that would give the highest impact forces toward regular asphalt. Three different rubber contents with 14, 28, 33 weight percent (% wt.) were implemented as the ground alongside one regular non-rubberized (0%) asphalt mixture, one baseline, and one extra-compliant playground rubber-composite material. The whole-body model was simulated to fall on the rubberized asphalt mixtures with an initial vertical velocity of 3 m/s with a 10° trunk angle and +10° anterior pelvis rotation. The impact forces were measured on the femoral head, and a previously developed hip fracture risk function was used to compare the rubberized asphalt mixtures. It was found that the rubberized asphalt mixture with 33% wt. rubber can reduce the impact forces up to 10% for the elderly male and female model compared to regular asphalt. The impact forces were most reduced for the extra-compliant playground material, with a 23% reduction for the female model. The risk of injury for the asphalt mixture with 33% wt. rubber was reduced up to 18% for elderly females and 20 for elderly males, compared to regular asphalt. The extra-compliant playground material had the most reduction of hip fracture risk for both sexes, 39 and 43% for elderly females and males, respectively. This study was jointly supported by a grant from “BVFF – Bana väg för framtiden” (BVFF number 2016-025) and Sweden’s innovation agency, Vinnova (D.nr.: 2013-04465, 2021-01598).</p
BRAVENT – Storskala branntester (del 2): Effekten av ventilasjonsstrategi på røykspredning og trykkontroll i en mock-up skolebygning
No full textBRAVENT – Large-scale fire tests (part 2): The effect of the ventilation strategy on smoke dispersion and pressure control in a mock-up school building In the overall BRAVENT project, the goal is to generate answers and documentation on current issues related to ventilation and fire by examining these with experimental fire tests. The present study aimed to evaluate how different failure mechanisms identified in sub-report 1, "Fire performance for non-fire rated ventilation components" [5], affect the pressure conditions and possible smoke spread in the building. In order to investigate the ventilation system's ability to control pressure balance and smoke spread in the event of a fire, 14 large-scale fire tests with different fuel types were carried out. The tests were conducted in a test building with several rooms representing a classroom, an office and a corridor. The fire tests were designed to investigate relevant fire scenarios for school buildings, but the findings from the tests may also be relevant for other purpose-built buildings. The building was equipped with a full-fledged damper-optimized ventilation system which was sized to serve a total of 450 m2 and thus provide a realistic basis for the fire tests. In sub-report 1, a number of component failures were uncovered when the system was exposed to hot smoke. The failure mechanisms led to the system losing its status and control over the dampers, thus also losing the overview of which air volumes passed through the dampers. The failure of the dampers then led to an imbalance in the ventilation system, also in rooms other than the fire room. In the extreme, this can lead to challenges in connection with escape by making it difficult or impossible to open doors. Smoke spread via the supply air ducts can occur due to smoke backflow if the pressure in the fire compartment exceeds the pressure in the supply air duct. In the experiments, the ventilation system increased to the maximum design airflow rate (Vmax) upon fire detection, and no smoke spread due to backflow of fire smoke in the supply air ducts was observed. It was not tested whether a backflow of smoke could have also been prevented at lower airflow rates than Vmax. Whether the ventilation system maintains sufficiently high pressure in the supply air duct to prevent backflow depends on, among other things, the capacity of the supply air fans, the density of the fire compartment and how quickly the fire develops. The smoke from the fire caused the filter in the unit to gradually clog. In three tests, the filter was clogged so much that the air handling unit could not extract enough air, which created an imbalance in the ventilation system. The new BRAVENT tests show that the size of the fire in relation to the air handling unit's capacity plays an important role in how long the exhaust airflow can be maintained. An air handling unit serving several small fire cells with limited available fuel will be able to maintain the required exhaust air volume longer than an aggregate serving a few large fire cells as the ratio between smoke volume and total air volume changes. Other factors that affect how long the unit can compensate for filter clogging are: • whether the air handling unit is designed for 100% or less simultaneity, i.e. the proportion of rooms that can have the maximum amount of airflow at the same time, • the condition of the filter at the start of the fire, completely new filters were used in each of the fire tests, • whether the ventilation system operates with Vmax or less airflow when a fire alarm is triggered. No smoke spread between the rooms via the exhaust duct was observed. However, since the exhaust airflow rate in one of the tests was significantly reduced to around 50% of the maximum design airflow rate, it is concluded that gradual clogging of the exhaust filter will increase the risk of smoke spreading via the exhaust duct. Clogging of the filters can be avoided by establishing a bypass. Nevertheless, it must then still be documented that all other functions of the ventilation system are safeguarded in the event of a fire. The tests carried out showed that the failure mechanism of some components (measurement errors in dampers, short circuits and clogging of the exhaust filters) can lead to the whole system no longer being able to maintain its function.Finansiert av: Norges forskningsråd, program SAMRISK-2-Samfunnssikkerhet og risiko, prosjektnummer 321099 og prosjektpartnerne</p
User-centered circular value propositions – approaches in practice and research
No full textCircular value propositions enable companies to build business models based on value preservation and circular resource flows. Circular value propositions also allow people to live more sustainably by facilitating increased utilization and resource efficiency. However, despite potential, transitions to circular business models remain low. One reason may be that circular value propositions are less attractive because they are often not developed with a user-centered approach and thus fail to meet people’s everyday needs. Through interviews with 13 companies and a literature study, this paper explores how companies consider user needs and involve users during development of circular value propositions. It also identifies conditions and actions that aid development of attractive circular offers. The findings are synthesized in a framework describing six enabling conditions and a definition of user-centered circular value propositions useful for circular economy practice and research. The authors would like to thank the interview participants for so openly sharing their experiences and valuable insights. The authors also acknowledge the two anonymous reviewers for their feedback which contributed to enhancing this manuscript. The research presented in this paper is part of the project Game-Based Approaches to Create Innovative Circular Value Propositions ( https://www.ri.se/en/what-we-do/projects/circular-co-creation-games ), which has received funding from the Swedish research council FORMAS , grant number 2021-02521 .</p
Energy, Exergy, Economic and Exergoeconomic Analyses of Chemical Looping Combustion Plant Using Waste Bark for District Heat and Power Generation with Negative Emissions
No full textThe greenhouse gas emissions from the boiler of pulp and paper industries can be minimized by adapting chemical looping combustion (CLC) technology. This work aims to analyze the energy, exergy, economic, and exergoeconomic performance of an industrial scale CLC plant for district heat and electricity generation using waste bark from the paper and pulp industry. The CLC plant with one natural ore and one industrial waste oxygen carrier (OC) is modeled using Aspen Plus. The performance of the CLC plant has been compared to Örtofta combined heat and power plant without CO2 capture and with post-combustion CO2 capture as the reference cases. Results showed that the CLC-based power plant is energetically, exegetically, and economically efficient compared to the reference cases. The circulating fluidized bed boiler unit contributes the highest exergy destruction (about 50–80%). Among the CO2 capture plants, the CLC plant with ilmenite has the lowest levelized cost of district heat (4.58 € GJ−1), and a payback period (9.69 years) followed by the CLC plant with LD slag (5.91 € GJ−1 and 11.84 years), and the plant with PCC (6.94 € GJ−1 and 13.58 years). The exergoeconomic analysis reveals that the CLC reactors have the highest cost reduction potential, followed by the steam turbine. This project was financed by the Chalmers Area of Advance Energy and J. Gust. Richert stiftelse.</p
Impacts of regular head waves on thrust deduction at model self-propulsion point
No full textThe results obtained from the self-propulsion simulations using Computational Fluid Dynamics (CFD) in the current study, for a ship free to heave, pitch and surge with the means of a weak spring system, are combined with the formerly executed CFD results of the bare hull and propeller open water simulations to investigate the impacts of regular head waves on the propeller-hull interactions in comparison to calm water, at the self-propulsion point of the model. Despite a rather significant dependency of the nominal wake on the wave conditions, the Taylor wake fraction remains almost unchanged in different studied waves which is around 12% lower than the calm water value. The thrust deduction factor in waves is reduced (12.8%–26.1%) in comparison to the calm water value. The change of thrust deduction factor is found to be associated with the boundary layer contraction/expansion and vortical structure dynamics, originating from the wave orbital velocities as well as the significant shaft vertical motions and accelerations that resulted in a modified propeller action, and consequently diminished suction effect on the aft ship. The altered thrust deduction factor and wake fraction in waves in comparison to calm water underlines the significance of waves on the propulsive factors and propeller design. This research is funded by The Swedish Transport Administrationthrough Lighthouse (Swedish Maritime Competence Center). The simulations were performed on the resources provided by the NationalAcademic Infrastructure for Supercomputing in Sweden (NAISS) and the Swedish National Infrastructure for Computing (SNIC) at Chalmers Centre for Computational Science and Engineering (C3SE) and National Supercomputer Center at Linköping University (NSC) partiallyfunded by the Swedish Research Council through grant agreements no.2022-06725 and no. 2018-05973</p
Modulärt batteribytessystem för arbetsmaskiner – slutrapport
No full textModular battery swap system for work machines The project has developed and demonstrated how a modular battery swap system can be used in electric work machines in various industries. The purpose of the project was to demonstrate innovative technology where battery swap technology enables battery-powered machines in agriculture and forestry. The project has completed the following: 1. Designed and built a modular battery pack for work machines 2. Designed and built an automatic battery swap station 3. Completed a prototype for an autonomous electric agricultural machine 4. Electrically converted a machine for forestry We have succeeded in creating a working battery swap concept. The concept has been shown at several different demo events. The project has received a lot of positive publicity in the media. The project creates opportunities to run work machines in agriculture and forestry without the batteries needing to be unnecessarily large, heavy and expensive to carry with the machine in the field. Building electrified work machines is not a big deal. What is new in this project is that we demonstrate a battery replacement system for work machines - that works in real life! The project group has worked hard together for two years and achieved brilliant results that we are very pleased with. As expected, it took some time to agree on a concept for the common component battery pack, but once it was set, work took off. In the project, we have built seven battery packs, two electric work machines and a battery swap station including electrical system, control system and other adaptations. This would not have been possible without a dedicated and very talented project group
Effect of absorption of laser light in mirrors on Fabry-Pérot based refractometry
No full textThis work models and experimentally assesses the influence of absorption of laser light in mirrors in Fabry-Pérot based refractometers used for realization of pressure. Model parameters are assessed by experimental characterizations. Characterizations of two refractometers agree well with the predictions of the model. It is shown that, when pressures are assessed in the viscous region, the absorption of laser light in mirrors will give rise to a small alteration in the proportional response and a pressure-independent offset, where the latter is significant for He but considerably smaller for Ar and N2Funding. VINNOVA (2018-04570); Vetenskapsrådet (2020-05105); European Partnership on Metrology (22IEM04-MQB-Pascal) which is cofinanced from the European Union’s Horizon Europe Research and Innovation Programme andby the participating states.</p
CF/PEEK skins assembly by induction welding for thermoplastic composite sandwich panels
No full textA method to assemble sandwich panels made of carbon fibre reinforced poly-ether-ether-ketone (CF/PEEK) facesheets and 3D-printed poly-ether-imide (PEI) honeycomb cores using induction welding is presented. Induction heating patterns inside CF/PEEK laminates of variable dimensions are first evaluated with a thermal camera and compared to a COMSOL Multiphysics model. Sandwich samples are then prepared by vacuum-assisted continuous induction welding under parameters selected from the modelling effort. Joining of sandwich panels made of CF/PEEK facesheets by induction welding under vacuum is demonstrated. Facesheets do not deconsolidate in the process and core crushing is avoided. Flatwise skin/core strength of the welded samples reaches up to 7 MPa, above reported performance for thermoset or thermoplastic composite sandwich panels. sThis work was funded by CREPEC (Research Center for High Performance Polymer and Composite Systems), NSERC (Natural Sciences and Engineering Research Council of Canada) (grant number ALLRP R.G. Martin et al. Composites Part B 284 (2024) 11167611556497-20), PRIMA Qu´ebec (Pole ˆ de Recherche et d’Innovation en Mat´eriaux Avanc´es) (grant number R20-13-004), the Canadian Space Agency (CSA), Ariane Group, NanoXplore inc, M¨ekanic and Dyze Design. </p
Adopting automated bug assignment in practice — a longitudinal case study at Ericsson
No full text[Context] The continuous inflow of bug reports is a considerable challenge in large development projects. Inspired by contemporary work on mining software repositories, we designed a prototype bug assignment solution based on machine learning in 2011-2016. The prototype evolved into an internal Ericsson product, TRR, in 2017-2018. TRR’s first bug assignment without human intervention happened in April 2019. [Objective] Our study evaluates the adoption of TRR within its industrial context at Ericsson, i.e., we provide lessons learned related to the productization of a research prototype within a company. Moreover, we investigate 1) how TRR performs in the field, 2) what value TRR provides to Ericsson, and 3) how TRR has influenced the ways of working. [Method] We conduct a preregistered industrial case study combining interviews with TRR stakeholders, minutes from sprint planning meetings, and bug-tracking data. The data analysis includes thematic analysis, descriptive statistics, and Bayesian causal analysis. [Results] TRR is now an incorporated part of the bug assignment process. Considering the abstraction levels of the telecommunications stack, high-level modules are more positive while low-level modules experienced some drawbacks. Most importantly, some bug reports directly reach low-level modules without first having passed through fundamental root-cause analysis steps at higher levels. On average, TRR automatically assigns 30% of the incoming bug reports with an accuracy of 75%. Auto-routed TRs are resolved around 21% faster within Ericsson, and TRR has saved highly seasoned engineers many hours of work. Indirect effects of adopting TRR include process improvements, process awareness, increased communication, and higher job satisfaction. [Conclusions] TRR has saved time at Ericsson, but the adoption of automated bug assignment was more intricate compared to similar endeavors reported from other companies. We primarily attribute the difference to the very large size of the organization and the complex products. Key facilitators in the successful adoption include a gradual introduction, product champions, and careful stakeholder analysis.
System identification of a physics-informed ship model for better predictions in wind conditions
No full textSystem identification offers ways to obtain proper models describing a ship’s dynamics in real operational conditions but poses significant challenges, such as the multicollinearity and generality of the identified model. This paper proposes a new physics-informed ship manoeuvring model, where a deterministic semi-empirical rudder model has been added, to guide the identification towards a physically correct hydrodynamic model. This is an essential building block to distinguish the hydrodynamic modelling uncertainties from wind, waves, and currents – in real sea conditions – which is particularly important for ships with wind-assisted propulsion. In the physics-informed manoeuvring modelling framework, a systematical procedure is developed to establish various force/motion components within the manoeuvring system by inverse dynamics regression. The novel test case wind-powered pure car carrier (wPCC) assesses the physical correctness. First, a reference model, assumed to resemble the physically correct kinetics, is established via parameter identification on virtual captive tests. Then, the model tests are used to build both the physics-informed model and a physics-uninformed mathematical model for comparison. All models predicted the zigzag tests with satisfactory agreement. Thus, they can indeed be considered as being mathematically correct. However, introducing a semi-empirical rudder model seems to have guided the identification towards a more physically correct calm water hydrodynamic model, having lower multicollinearity and better generalization.The authors would like to acknowledge the financial support from Trafikverket/Lighthouse (grant id: FP4 2020) to prepare this paper. They would also thank all personnel at SSPA who have been involved in creating the model test results, building the ship models, and conducting the experiments.</p