This research investigates the potential of a game-theoretic-based Active Yaw Control (AYC) strategy to enhance power generation in wind farms. The proposed AYC strategy in this study replaces traditional look-up tables with a trained Artificial Neural Network (ANN) that determines the optimal yaw misalignment for turbines under time-varying atmospheric conditions. The study examines a hypothetical 3x2 rectangular arrangement of NREL 5-MW wind turbines. The FAST.Farm simulation tool, utilizing the dynamic wake meandering (DWM) model, is employed to assess both the power performance and structural load on the wind turbines. When tested with two different inflow directions and ambient turbulence (10%), the AYC strategy demonstrated a maximum increase in total power output of 2.6%, although it affected individual turbines differently. It also exhibits an increase in some structural loads, such as tower-top torque, while some components experience a slight reduction in load. The results underscore the effectiveness of the ANN-guided game-theoretic algorithm in improving wind farm power generation by mitigating the negative impact of wake interference, offering a scalable and efficient method for optimizing large-scale wind farm. However, it is essential to evaluate the overall impact of AYC on wind farm efficiency in terms of both Annual Energy Production (AEP) and structural loading under various atmospheric conditions. 

Sweden has an ambitious plan to fully decarbonise district heating by 2030 and to contribute with negative emissions of greenhouse gases in 2050. The vagaries of the energy market associated with climate, political, and social changes entail cross-sectoral integration that can fulfill these national targets. Fifth-generation district heating and cooling (5GDHC) is a relatively new concept of district energy systems that features a simultaneous supply of heating and cooling using power-to-heat technologies. This paper presents best practices for developing 5GDHC systems in Sweden to reach a consensus view on these systems among all stakeholders. A mixed-method combining best practice and roadmapping workshops has been used to disseminate mixed knowledge and experience from middle agents representing industry professionals and practitioners. Four successful implementations of 5GDHC systems are demonstrated and the important learned lessons are shared. The best practices are outlined for system planning, system modeling and simulation, prevailing business models for energy communities, and system monitoring. A roadmap from the middle agents’ point of view is composed and can be utilised to establish industry standards and common regulatory frameworks. © 2023 The Author(s)

Information-centric networks (ICNs) intrinsically support multipath transfer and thus have been seen as an exciting paradigm for IoT and edge computing, not least in the context of 5G mobile networks. One key to ICN's success in these and other networks that have to support a diverse set of services over a heterogeneous network infrastructure is to schedule traffic over the available network paths efficiently. This paper presents and evaluates ZQTRTT, a multipath scheduling scheme for ICN that load balances bulk traffic over available network paths and schedules latency-sensitive, non-bulk traffic to reduce its transfer delay. A new metric called zero queueing time (ZQT) ratio estimates path load and is used to compute forwarding fractions for load balancing. In particular, the paper shows through a simulation campaign that ZQTRTT can accommodate the demands of both latency-sensitive and-insensitive traffic as well as evenly distribute traffic over available network paths. 

This work presents synthesis and spectroscopic characterization of a new metal-organic framework (MOF). The compound Fe-BDC-DMF was synthetized by the solvothermal method and prepared via a reaction between FeCl3.6H2O and benzene-1,4-dicarboxylic acid (H2BDC) or terephthalic acid using N,N-dimethylformamide (DMF) as solvent. The powder was characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) analysis. The electrochemical properties were investigated in a typical lithium-ion battery electrolyte by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charging and discharging. The synthetized Fe-BDC-DMF metal-organic framework (MOF) contains a mixture of three phases, identified by PXRD as: MOF-235, and MIL-53(Fe) monoclinic with C2/c and P21/c space groups. The structure of the Fe-BDC is built up from Fe3+ ions, terephalates (BDC) bridges and in-situ-generated DMF ligands. The electrochemical measurements conducted in the potential range of 0.5–3.5 V vs. Li+/Li0 show the voltage profiles of Fe-BDC and a plateau capacity of around 175 mAh/g. © 2022 The Author(s)

Residual stresses created during the packaging process can adversely affect the reliability of electronics components. We used incremental hole-drilling method, following the ASTM E 837-20 standard, to measure packaging induced residual stresses in discrete packages of power electronics components. For this purpose, we bonded a strain gauge on the surface of a Gallium Nitride (GaN) power component, drilled a hole through the thickness of the component in several incremental steps, recorded the relaxed strain data on the sample surface using the strain gauge, and finally calculated the residual stresses from the measured strain data. The recorded strains and the residual stresses are related by the compliance coefficients. For the hole drilling method in the isotropic materials, the compliance coefficients are calculated from the analytical solutions, and available in the ASTM standard. But for the orthotropic multilayered components typically found in microelectronics assemblies, numerical solutions are necessary. We developed a subroutine in ANSYS APDL to calculate the compliance coefficients of the hole drilling test in the molded and embedded power electronics components. This can extend the capability of the hole drilling method to determine residual stresses in more complex layered structures found in electronics. 

Additive manufacturing (AM) of large-scale polymer and composite parts using robotic arms integrated with extruders has received significant attention in recent years. Despite the contributions of great technical progress and material development towards optimizing this manufacturing method, different failure modes observed in the final printed products have hindered its application in producing large engineering structures used in aerospace and automotive industries. We report failure modes in a variety of printed polymer and composite parts, including fuel tanks and car bumpers. Delamination and warpage observed in these parts originate mostly from thermal gradients and residual stresses accumulated during material deposition and cooling. Because printing large structures requires expensive resources, process simulation to recognize the possible failure modes can significantly lower the manufacturing cost. In this regard, accurate prediction of temperature distribution using thermal simulations is the first step. Finite element analysis (FEA) was used for process simulation of large-scale robotic AM. The important steps of the simulation are presented, and the challenges related to the modeling are recognized and discussed in detail. The numerical results showed reasonable agreement with the temperature data measured by an infrared camera. While in small-scale extrusion AM, the cooling time to the glassy state is less than 1 s, in large-scale AM, the cooling time is around two orders of magnitudes longer. © 2022 by the authors

This work presents a novel numerical methodology to model the degradation and failure of composite materials like GFRP submitted to monotonic and high cycle fatigue loads. This is done by using the Serial–Parallel Rule of Mixtures homogenisation technique together with a proper mechanical characterisation of the constituent materials of the composite. This paper also proposes an efficient way of estimating the fatigue properties of each of the material constituents (fibre or matrix) to comply with the experimental results obtained at composite level; this enables to estimate the fatigue strength of any stacking/orientation of fibres with only one mechanical characterisation of the material properties. A comparison of the results obtained analytically and experimentally for GFRP is presented. The results show the applicability and accuracy of the proposed methodology in this field.

It is common today that operational data is recorded onboard ships within the Internet of Ships (IoS) paradigm. This enables the possibility to build ship digital twins as digital copies of the real ships. Predicting the ship’s motions with ship dynamics could be an important sub-component of these ship digital twins. A model for the ship’s dynamics can be identified based on observations of the ship’s motions. The identified model will have model uncertainty due to imperfections and idealizations made in physical model formulations as well as uncertainty from errors in the measurement data, which can be very pronounced when using full scale operational data. It is easier to develop accurate models with low model uncertainty using data obtained in a controlled laboratory environment where the measurement errors are much lower, especially in calm water conditions. The prediction model should be able to describe scenarios that a ship has never encountered before, which is possible if much of the underlying physics has been identified. Grey-box modelling is a technique which combines operational data with physical principles to achieve this. The objective of this thesis is to develop system identification methods for grey box models with good generalization of the model scale rigid body ship dynamics in calm waters. A model development procedure is proposed to handle the model uncertainty through the selection of candidate models based on a hold-out evaluation procedure. The measurement noise is handled by an iterative preprocessor, which uses an extended Kalman filter (EKF) and a Rauch Tung Striebel (RTS) smoother that uses an initially estimated predictor model from semi-empirical formulas. It is demonstrated that the ship’s roll motion with high accuracy can be described using a quadratic damping model. For the more complex manoeuvring models, multicollinearity is a large problem where the appropriate complexity needs to be selected with the bias-variance trade-off between underfitting or overfitting the data. Hold-out turning circle tests were predicted with high accuracy for the wPCC and KVLCC2 test case ships with models from the proposed development procedure and parameter estimation method. The proposed methods can produce prediction models with high generalization given that a suitable model structure has been selected from the candidate models and an appropriate split in the hold-out evaluation of the model development process has been applied.

Getting the best possible accuracy with the lowest possible computational cost is an important factor in the early design stage of ships. Potential flow-based analysis presents such a solution for seakeeping analyses. The accuracy of roll motion in potential flow is however not so good, due to the large influence from vicsous roll damping, which is missing in these calculations. This paper proposes a hybrid method, as a solution to this problem, where the viscous roll damping from Ikeda’s semi-empirical method is injected into an existing 3D unsteady fully nonlinear potential flow (FNPF) method. The hybrid method is investigated using roll decay tests with the KVLCC2 test case. This investigation shows that the accuracy of simulated roll motions is significantly improved and also shows good agreement with the corresponding roll decay model tests.

Having an accurate prediction of ship roll damping is crucial when analysing roll motions. In this paper, the simplified Ikeda method (SI-method) is compared with the original Ikeda method. The methods are compared using results from a database of roll decay tests carried out on modern merchant ships and a smaller set of predictions in which the original Ikeda method was used. It was found that most of the ships in the database had dimensions outside the limits of the SI-method. Thus, the SI-method showed poor agreement with model tests outside its limits but acceptable agreement for ships within limits. It was found that the deviations were caused by extrapolation errors of the wave-damping in the SI-method. Two ways to improve the accuracy of the SI-method were proposed based on regression, which gave about the same accuracy as the original Ikeda method. © 2021 The Author(s).

System 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.

It is essential to describe a ship’s manoeuvrability for various applications, e.g. optimal control of unmanned surface vehicles (USVs). In this study, the capability of two recognised manoeuvrability models to predict ships’ trajectories is investigated based on both simulation and open-water experiment test data. The parameters of these models are estimated by a statistical learning method. The goodness of the two estimated models for describing a merchant ship’s manoeuvrability is first studied using her manoeuvring simulation data. Then, experimental manoeuvring tests to use a USV in open water with wind and drifting effects are used to check the conventional model identification procedures. Finally, some modifications and adjustments are proposed to improve the conventional procedures. It shows that the proposed procedures can accurately derive the ship’s manoeuvrability based on experimental data. © 2022 The Author(s). 

This paper discusses the results from extensive wake wash measurements carried out with a model of a ROPAX ship passing a bay. The tests were carried out in SSPA’s sea-keeping and maneuvering basin. This model had been subjected to wash wave measurements in open water in previous tests, which gave possibilities for comparisons between restricted and unrestricted waters. Six wave gauges were placed inside and outside the bay, and a significant drawdown was noticed in addition to amplifications of the Kelvin waves. The drawdown and the Kelvin waves that occurred in the bay are difficult to explain, but this paper makes an attempt to analyze the phenomena that occur. The different wave theories that can be used in this case are presented. The methods that are used for analyzing the measured signals are described. One conclusion that can be made is that drawdown caused by the Bernoulli wave can probably be considered a worse problem than ordinary wash waves (Kelvin waves) in restricted and especially shallow waters when looking at large displacement ships.

Engineering companies face the challenge of optimising margins within product platforms while balancing individual product optimisation and maximising platform commonality. Key obstacles include organisational silos, diverse design variables, design space allocation, and varying time perspectives. This paper proposes a value-based modelling methodology that integrates both internal and external variety within the manufacturer. Using an automotive Head-Up Display (HUD) case study, we demonstrate how to effectively utilise platform margins to maximise technological variety and minimise internal variety, thereby enhancing long-term system value. This approach helps design teams understand the implications of their decisions, optimise platform margins to meet evolving technological demands, reduce costs, and maximise value. Our findings advance the understanding of margin optimisation in product platforms and support informed decision-making for engineering companies facing conflicting objectives. 

At the onset of the pandemic in spring 2020, the Swedish shipping sector was first affected by border closures preventing passengers to use RoPax shipping and cruise ferries. There were some blank sailings but in general they kept operating to foster intra-European trade by trucks despite the missing revenues from passengers. Shipping in general was affected by port disrup-tions and complicated crew changes. Eventually, however, it was clear that the most dramatic disruptions on a global scale where experienced in the container segment. General media reported on delayed goods, high freight rates and, however not related to the pandemic, the Ever Given blocking the Suez Canal for a week in March 2021. Currently, there are few reports of supply chains and shipping suffering from disruptions and capacity constraints related to the pandemic. The peak in freight rates was rather replaced by depressed rates and there is a certain risk that some logisticians and supply chain managers regard the pandemic as a once-in-a-lifetime event and just want to get back to a previous be-haviour seeing container shipping as a commodity with indefinite capacity at a reasonable price. Nevertheless, the war in Ukraine, the drought in the Panama Canal and the attacks by the Houthi rebels in the Red Sea create other problems for container shipping. Freight rates increase significantly, but from very low levels. The purpose of the report is to describe and analyse how international container shipping was affected by the Covid-19 pandemic and other disruptions. The analysis takes a Swedish perspective on disruptions and tries to go beyond the anecdotal reporting and capture what happened and why. Container shipping is put into a context of economy, consumption, world trade, supply chains and logistics. The pandemic and more current events affecting container shipping market are described together with how shipping lines responded. A series of interviews with Swedish actors revealed how they perceived the disruptions and what countermeasures the actors have applied to mitigate the effects, their organisational learning and how they prepare for future disruptions

This study originates in a recognised unsustainable cost escalation for complex defence equipment. In order to understand how such cost escalation for complex product systems (CoPS) can be avoided, this study comparatively explores four different industrial sectors–energy, transportation, healthcare and defence–with and without intergenerational increasing costs, represented by four international companies. The results, collected from studying the development of one of each company’s products, reveal some characteristic differences in market factors between those sectors and companies having problems with intergenerational escalating costs and customer affordability, as compared to other sectors and companies. It is suggested that dependent on market characteristics, it might be necessary to actively manage affordability when CoPS are developed. Efforts made by the companies to make products more affordable were identified, and several factors enabling and disabling the development of less costly products without compromising customer needs were explored. Further, the implications of affordability management in a CoPS setting are elaborated on.

A secondary measurement standard filling the gap between the available static and dynamic standards was developed. The standard utilizes a quick-opening valve and bursting diaphragms to generate step-like pressures with amplitude of few kilopascals to 10 MPa and with frequency content from 10-2 Hz to 800 Hz. An important design feature of the developed standard lies in the usage of aluminium diaphragms, allowing short rise times and high frequency content. The standard is based on two reference sensors, calibrated statically and dynamically. The reference sensors showed a linear dynamic response in the intermediate frequency range and was in good agreement with the static calibration results. Therefore, extrapolation of shock tube results was implemented. To demonstrate the capabilities of the developed standard, three pressure measurement systems were characterized, and their respective dynamic response was calculated. The results show that the developed standard can provide calibration information that are not currently available.

In this paper, we introduce a robust method for dynamic characterization of pressure measuring systems used in time-varying pressure applications. The dynamic response of the pressure measuring systems in terms of sensitivity and phase as a function of frequency at various amplitudes of the measurand can be provided. The shock tube which is the candidate primary standard for dynamic pressure calibration at the National Laboratory for pressure, Sweden, was used to realize the dynamic pressure. The shock tube setup used in this study can realize reference pressure with amplitudes up to 1.7 MPa in the frequency range from below a kilohertz up to a megahertz. The amplitude of the realized step pressure was calculated using the Rankine–Hugoniot step relations. In addition, the accurate time of arrival of the generated shock at the device under test (DUT) was measured using an optical probe based on shadowgraphy. The optical detector has a response time in nanosecond time scale which is several orders of magnitude faster than the response time of any pressure measuring system. Hereby, the latency between physical stimuli and response of the DUT can be measured. By the knowledge of the amplitude and the accurate time of arrival of the reference step pressure, the transfer function of the DUT can be calculated and presented in Bode diagrams of sensitivity and phase response versus frequency. The uncertainty in sensitivity and phase measurements was estimated. The information provided by this work is useful for developing reliable models of dynamic pressure measuring system and provide accurate information about their dynamic response. That in turn will contribute to establish a traceability chain for dynamic pressure calibration.

Accurate dynamic pressure measurements are increasingly important. While traceability is lacking, several National Metrology Institutes (NMIs) and calibration laboratories are currently establishing calibration capacities. Shock tubes generating pressure steps with rise times below 1 µs are highly suitable as standards for dynamic pressures in gas. In this work, we present the results from applying a fast-opening valve (FOV) to a shock tube designed for dynamic pressure measurements. We compare the performance of the shock tube when operated with conventional single and double diaphragms and when operated using an FOV. Different aspects are addressed: shock-wave formation, repeatability in amplitude of the realized pressure steps, the assessment of the required driver pressure for realizing nominal pressure steps, and economy. The results show that using the FOV has many advantages compared to the diaphragm: better repeatability, eight times faster to operate, and enables automation of the test sequences.

This study investigated the properties and sustainability of cement-bonded composites containing industrial residues such as wood chips, tyre fibres and biomass combustion residues, i.e. bottom ash (BA) and fly ash (FA). The effect of cement-to-raw material (wood/tyre fibre) ratio (C/RM) and the aggregate content (BA and FA) on thermal and mechanical properties of the composites were investigated. Scanning electron microscopy (SEM) and life cycle analysis (LCA) were also conducted. The results revealed that as the aggregate content increased in wood composites, the mechanical properties also increased. The mean thermal conductivity and volumetric heat capacity of tyre composite samples were 0.37 W/mK and 1.2 MJ/m3K respectively, while the respective values for wood composite samples were 0.29 W/mK and 0.81 MJ/m3K. SEM analysis showed adequate bonding between wood/tyre fibres and cement matrix. LCA revealed that the materials share of the total primary energy use was about 60% for all analysed composites. © 2021 The Author(s)

Experience with wooden multi-storey houses have shown that impact sound insulation is one of most critical issues to ensure a good indoor environment. Even in cases where the impact sound insulation is fulfilled, people perceive the sound from e.g. walking neighbours as very disturbing. To investigate the subjective perception, a test facility is needed which allows for a coherent evaluation of different floor designs by listening test. The facility should ensure, that when comparing different floors, the same excitation by a walker and the same receiving room are involved. Only the floor design should be changed. As a consequence the spread in the data will only be due to the spread in the perception by subjects. In this paper a virtual design tool for low frequency impact sound insulation is presented, which consists of four parts; measured walking forces, floor models, an auralisation system which consists of a grid of loudspeakers simulating the vibration of the floor and a receiving room furnished as a common living room. In a pilot study a listening test is carried out for 13 different floors with different impact sound spectra at frequencies below 100 Hz. The results indicate that the judged annoyance strongly correlates with the judged loudness. However, there is a substantial spread observed in between the subjects participating in the listening tests. To understand this spread, a more extended study is needed with more participants and a classification of the subjects with respect to criteria such as noise sensitivity or age.

Low-frequency impact sound caused by upstairs neighbors walking on the floor is a key acoustic challenge regarding lightweight floors and a major source of disturbance particularly in wooden buildings. To investigate the effect of floor design on the perceived walking sound, a virtual design tool has been developed, which allows for auralising the impact sounds containing low frequencies down to 20 Hz. Using this tool, footstep sounds on 10 different lightweight floors were auralised by a loudspeaker grid mounted in the ceiling of an acoustically controlled lab, which is furnished as a common living room. The walking sounds were subjectively evaluated through listening tests while the subjects were sitting freely on a sofa without needing to use any extra listening equipment. The listening test results suggest that loudness, thumpiness and reverberation are correlated with the perceived annoyance. The results also indicate a correlation between annoyance and age as well as the individual experience of earlier exposure to noise.

Low-frequency impact sound caused by upstairs neighbors walking on the floor is a key acoustic challenge regarding lightweight floors and a major source of disturbance particularly in wooden buildings. To investigate the effect of floor design on the perceived walking sound, a virtual design tool has been developed, which allows for auralising the impact sounds containing low frequencies down to 20 Hz. Using this tool, footstep sounds on 10 different lightweight floors were auralised by a loudspeaker grid mounted in the ceiling of an acoustically controlled lab, which is furnished as a common living room. The walking sounds were subjectively evaluated through listening tests while the subjects were sitting freely on a sofa without needing to use any extra listening equipment. The listening test results suggest that loudness, thumpiness and reverberation are correlated with the perceived annoyance. The results also indicate a correlation between annoyance and age as well as the individual experience of earlier exposure to noise. © 2023 First author et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

In this article, we report on a carbon-coated optical fiber that is suitable to be used simultaneously as a transmission medium and as a sensor. It consists of a standard single mode fiber (SMF) sleeved in two layers of coating, which provide protection and isolation from external elements. The inner layer is made of carbon, whereas the outer is made of polymer. When the fiber is subjected to mechanical stress, the electrical resistance of the carbon layer changes accordingly. The voltage variations caused by the former can be measured with high accuracy and without interfering with the light propagating through the SMF. In this work, the feasibility of this operating principle is demonstrated in a low coherence Michelson interferometer in which electrical and optical signals were measured simultaneously and compared to each other. Results indicate that electrical measurements are as precise as the optical ones and with linear behavior, reaching a sensitivity of 1.582 mV/με and able to detect vibrations down to 100 mHz. © 2024 The Authors

Because of the successful application of hydrofoils on the America's Cup catamarans in the past two campaigns the interest in foiling sailing craft has boosted. Foils have been fitted to a large number of yachts with great success, ranging from dinghies to ocean racers. An interesting question is whether one of the slowest racing boats in the world, the Optimist dinghy, can foil, and if so, at what minimum wind speed. The present paper presents a comprehensive design campaign to answer the two questions. The campaign includes a newly developed Velocity Prediction Program (VPP) for foiling/non-foiling conditions, a wind tunnel test of sail aerodynamics, a towing tank test of hull hydrodynamics and a large number of numerical predictions of foil characteristics. An optimum foil configuration is developed and towing tank tested with satisfactory results. The final proof of the concept is a successful on the water test with stable foiling at a speed of 12 knots.

This text is an extension of notes from courses first given during the 1990-ies for engineers employed in industry, and then for master students in the international masters programme at Chalmers Technical University in Gothenburg 2001-2009. Hence, it covers most issues of fatigue analysis as taught on the master level in universities. The micromechanical features of fatigue as studied in materials science constitute an area of research and education in itself. The descriptions here are simplistic. Some fundamental models are introduced just to give qualitative indications of the micromechanical background to fatigue phenomena. These models are useful for the understanding of principal effects found by experiments on the macroscopic level. Some emphasis is given to the stochastic nature of fatigue. The use of statistical methods in design is described as well as uncertainty assessments in the evaluation of experiments to find material properties connected to fatigue. Most of the mathematical expressions used in fatigue design are not physical laws but suitable models suggested from curve fitting of experimental results, and then a critical statistical assessment is essential. The aim is to supply an easy-to-use support to people working with fatigue in industrial environments or as teachers on the bachelor or master level in universities. It should give useful background and understanding to handbook formulas and requirements in standards. If the text is used in courses it should be complemented by examples and problems to solve since only a few examples of a principal character are included. Likewise, extensive handbook data for e g stress concentration and stress intensity factors, and material properties, are necessary for use in practical design situations. Computer programs for solving of various problems, as FEM codes or procedures to find load spectra are not included, since the field is changing quickly, and the Internet gives ample information. The intention has not been to produce a reference work for scientific studies of fatigue. Therefore, literature references are few and only including works of authors having produced milestone contributions to the area, or well renowned textbooks, standards, and handbooks. It is underlined that all experimental evidence shows that fatigue phenomena in real materials can by no means be precisely described by mathematical models and formulas. Models are sometimes developed in the text by sophisticated mathematical tools giving such an impression. But they are just models, often competing with one another, and they only constitute a framework for understanding and approximate data for design.

There is a large body of research available focusing on how ship hull conditions, including various hull coatings, coating defects, and biofouling, influence the boundary layer, and hence resistance and wake field of a ship. Despite this there seems to be little consensus or established best practice within the ship design community on how to model hull roughness for ship-scale CFD. This study reviews and compares proposed methods to model hull roughness, to support its use in the ship design community. The impact of various types of roughness on additional resistance and wake fields are computed and presented for the well-established test case KVLCC2. The surfaces included in the review are divided into three groups: 1) high quality, newly painted surfaces, 2) surfaces with different extent of poor paint application and/or hull coating damages; and 3) surfaces covered with light slime layers. The review shows the use of a variety of roughness functions, both Colebrook-type and inflectional with three distinct flow regimes, as well as a variety of strategies to obtain the roughness length scales. We do not observe any convergence within the research community towards specific roughness functions or methods to obtain the roughness length scales. The comparison using KVLCC2 clearly illustrates that disparities in surface texture cause large differences in additional resistance, and consequently no strong correlation to a single parameter, e.g. AHR (Average Hull Roughness). This implies that, to be able to select a suitable hull roughness model for a CFD-setup, more details of the surface characteristics are required, such as hydrodynamic characterization of hull coating and expected fouling. © 2020 The Authors

Installing an energy saving device such as a pre-swirl duct (PSD) is a major investment for a ship owner and prior to an order a reliable prediction of the energy savings is required. Currently there is no standard for how such a prediction is to be carried out, possible alternatives are both model-scale tests in towing tanks with associated scaling procedures, as well as methods based on computational fluid dynamics (CFD). This paper summarizes a CFD benchmark study comparing industrial state-of-the-art ship-scale CFD predictions of the power reduction through installation of a PSD, where the objective was to both obtain an indication on the reliability in this kind of prediction and to gain insight into how the computational procedure affects the results. It is a blind study, the KVLCC2, which the PSD is mounted on, has never been built and hence there is no ship-scale data available. The 10 participants conducted in total 22 different predictions of the power reduction with respect to a baseline case without PSD. The predicted power reductions are both positive and negative, on average 0.4%, with a standard deviation of 1.6%-units, when not considering two predictions based on model-scale CFD and two outliers associated with large uncertainties in the results. Among the variations present in computational procedure, two were found to significantly influence the predictions. First, a geometrically resolved propeller model applying sliding mesh interfaces is in average predicting a higher power reduction with the PSD compared to simplified propeller models. The second factor with notable influence on the power reduction prediction is the wake field prediction, which, besides numerical configuration, is affected by how hull roughness is considered. © 2022 The Authors

The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11-18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR.

BECCS from biogas production

Global CO₂ emissions amount to about 40 Gtonnes/year and they need to be rapidly reduced if we are to meet adopted climate targets. To achieve this, a variety of measures is needed, such as more electrification, reduced use of fossil energy, more renewable energy, energy efficiency improvements and CCS (Carbon Capture and Storage). However, this will not be enough, but will also require so-called negative emissions, which means that CO₂ is removed from the atmosphere through, for example, increased afforestation, increased carbon storage in soil (e.g. biochar), or by capturing and storing CO₂ of biogenic origin in geological formations, also known as bio-CCS or BECCS. At global level, the need for negative emissions is estimated to be in the order of several billion tonnes of CO₂ per year if it shall be possible to reach the 1.5-degree target and net zero emissions by 2050. At national level, Sweden’s target is to achieve net zero emissions by 2045 and from then on to be climate positive. This means that territorial emissions from the 1990 level must be reduced by at least 85% by 2045 and that the remaining 15 % will be eliminated by means of so-called supplementary measures including bio-CCS as an important measure.

The need for bio-CCS is significant and the actors who can deliver biogenic CO₂ at the right quality and at low cost will have good business opportunities in an expected future global marketplace for negative emissions. With this project, we have investigated the opportunities CO₂ from biogas production has to contribute to bio-CCS in Sweden. At biogas plants that produce vehicle gas, there is already equipment to separate CO₂ from biogas, so-called upgrading technologies. By modifying and extending this technology, pure liquid CO₂ can be generated. The CO₂ is then transported to terminals in Swedish ports while waiting for transport by ship to the place for permanent storage.

The project has studied gas purification and liquefaction based on the four most common upgrading techniques: water scrubber, PSA (pressure swing adsorption), membrane separation and amine scrubber. The residual gas (the CO₂-rich gas leaving the upgrading equipment) differs between different upgrading technologies, which affects the need for subsequent purification steps. Results from modelling and simulation have led to two proposed technology chains. For amine scrubbers, a simple process of compression, drying and liquefaction is sufficient to achieve the CCS specification of the liquid CO₂. PSA, membranes and water scrubbers require more advanced gas purification including a two-phase separation and recirculation of gases with low dew point, such as O₂ and CH₄. The recirculated gas is recycled to the inlet of the upgrading process, leading to the double benefit of increased amount of valuable CH₄ product and further reduction of greenhouse gas emissions to the atmosphere. A side effect is that the need for conventional residual gas management is eliminated.

Cost calculations have been carried out for biogas plants with a production capacity of 20, 50 and 120 GWh/year. With an availability of 95% and a CO₂ content of 39% in raw biogas (gas before upgrading), this equates to a CO₂ production of 2,400, 5,900 and 14,200 tons/year, respectively. A starting point for the study has been that systems for large-scale bio-CCS/CCS will be established and that this will lead to the construction of several CO₂ terminals in Swedish ports. Furthermore, it is assumed that these terminals allow third-party access where a supplementary volume of biogenic CO₂ from biogas plants can constitute a portion of the total managed amount. Around each terminal, clusters of biogas plants are estimated to emerge, which each can deliver approximately 20,000–100,000 tons CO₂ per year. The distribution from biogas plants to port terminals may be done by truck transport where the loading capacity amounts to 34 tons of CO₂. After the terminal, CO₂ is transported by ship to the place for permanent storage.

The cost of producing liquid CO₂ from biogas depends on local conditions such as CO₂ flow, O₂ content, upgrading technology, new or existing plant, transport distance to terminal, etc. In order to determine what the cost will be for each individual biogas plant, it is necessary to adapt the calculations to local conditions. Through the project, generic calculations have been carried out which show that large biogas plants have good opportunities to produce liquid CO₂ at competitive costs, but also that there is a strong scaling effect. For example, the cost is about SEK 200–300/tonne CO₂ for new plants with 120 GWh in annual biogas production. With investment support, the cost drops to about SEK 150–200/tonne. For new plants in the intermediate segment (50 GWh/year), the cost is slightly higher, SEK 300–450/tonne (without capital grants) and SEK 190–275/tonne (with capital grants). For smaller plants (20 GWh/year), the cost rises significantly, especially for water scrubbers.

The transport cost up to the terminal is affected by the distance and amount of CO₂ handled. For example, the cost of truck transport from larger biogas plants is about SEK 200/tonne at 100 km one-way to terminal. The total cost of bio-CCS from biogas including terminal handling, ship transport and final storage is affected by many parameters and there are uncertainties in cost estimates along the entire chain. In a calculation example for a biogas plant with membrane upgrading, 100 km of truck transport one way to terminal in Gothenburg and transport and final storage according to Northern Light's concept, the total cost was estimated at SEK 830–1020/tonne CO₂ for larger biogas plants (120 GWh/year).

When the bio-CCS from biogas is introduced, negative emissions arise from two sources, firstly from the final storage itself, which is the main part, and secondly by reducing CH₄ emissions from the upgrading plants, which is a smaller, but not negligible part. The total CO₂ efficiency of the value chain is determined by energy consumption, transport distance, selected storage solution and CH₄ slip before the introduction of bio-CCS. Emissions from truck transport are small in this context. In total, CO₂ efficiency in many cases amounts to close to 100%, i.e. net emissions in the value chain up to final storage are close to zero. For plants that initially had relatively high CH₄ emissions from the upgrading unit, the climate benefit is even greater, with CO₂ efficiency throughout the chain being well over 100%.

A driving hypothesis in the project has been that CO₂ from biogas can be the CO₂ stream in society that is one of the lowest-hanging fruits and that the value chain is well placed to be more cost-effective than other concepts for bio-CCS. Based on the results of the project, we can conclude that the hypothesis is likely to hold. The cost up to the terminal will in many cases likely be lower compared to capture and liquefaction from large point sources. With efficient technology and distribution solutions, biogas producers should be able to contribute to bio-CCS to a fairly large extent, up to about 10% of Sweden's need for negative emissions. For biogas operators, this would mean a broadening of the business where CO₂ is seen as a valuable product which complements the revenues from the production of biomethane. 

Autonomous delivery vehicles – what kind of vehicles are they and does it matter? The project GLAD – Goods deliveries during the last mile of self-driving vehicles explores how tomorrow's small autonomous delivery vehicles (ADV) could operate in the transport system. The goal of the GLAD project is to develop knowledge about the needs and challenges of such vehicles in Sweden before they are in real operation. In the project, there are several work packages that work with different challenges in relation to ADV. To explore these issues, the project has developed a prototype of an ADV, which is based on a vehicle which today is classified as a three-wheeled moped. But designed as an ADV it could be a different kind of vehicle. One result from one of the work packages in the project is that ADVs driving on public roads should maintain the same speed as other traffic to avoid critical traffic situations. This means that ADVs should be able to drive at a maximum speed of 70 km/h. Another requirement is that the ADVs should be able of carrying a load of 500 kg. These requirements are a conclusion from interviews with drivers of small manually driven delivery vehicles about how they experience today's traffic situations, from which type of road they use and how they use their vehicles. The purpose of this report is to identify obstacles and opportunities from a regulatory perspective to implement ADVs in Sweden in a safe way. Rules that may affect the development of ADVs are, for example, whether they are covered by the Machinery Directive or whether they should be type approved. Other rules concern license plates, motor liability insurance, where the vehicles may be driven and driving license requirements. The aim of the legislations is to create a safe vehicle to use. After a review of existing regulations, it is closest at hand that future ADVs, based on the requirements set in the project, are classified as a 4-wheel heavy motorcycle for the transport of goods. The vehicle also needs a type-approval. It can be argued that an ADV with that weight and speed will have a lot to prove from a safety perspective in a type-approval process and that a market introduction is therefore further away in time. If the speed requirements are lowered instead i.e., maximum of 30 km/h, it could be classified as a motor tool. The advantage of motor tools is that these must be CE-marked by the manufacturer, which in turn means that they have a shorter time to market because the process does not involve a type-approval agency.

It will be a few years before we have autonomous buses that drive around the city´s streets and squares without drivers. On the other hand, it should be possible to have autonomous buses in a depot at an early stage in order to have more efficient maintenance of the vehicles when they are not in services, while at the same time learning how to be part of the future operation. Such buses would be type-approved for manual traffic (SAE level 0-2), but not approved for autonomous road operation (SAE level 4-5).During one and the same day, the bus will therefore transfer between the regulations forfenced (depot) and non-fenced (road) areas, between being autonomous and notautonomous.The bus, which was previously a legal “static whole”, will now instead be tested based ontwo regulations depending on its current environment and level of autonomy. This is acompletely new situation, that a bus is “dynamically divisible” from a regulatory perspective, which in turn has consequences for who is to decide that the vehicle is safe to use in a certain environment.

After analysing the challenges based on existing regulations, interviewing relevant authorities, arranging workshops with various stakeholders and meetings with experts in certification, our conclusion is that the bus should be self-certified through CE marking according to the Machine Directive to be considered safe in autonomous mode within the depot. This is the authors´ conclusion and not necessarily representative for the other parties involved in the project.

Our prediction is also that we will see more of self-certification of autonomous vehicles in the future. Partly because there are such large international markets working that  way, such as the North America one, and partly because it enables a faster market introduction of dynamic vehicle concepts. With dynamic vehicle concept, we mean vehicles that gain new capacity by replacing the chassis or changing software settings and thus go from being a bus to a truck or from a car to a moped car. Maybe even several times a day.

But with self-certification, the need for standardization will also increase, both forprocesses and products. When it comes to processes, it can be about how to certify a vehicle, especially how to do the risk analysis. For products, standardized descriptions of the technology´s function will facilitate your own self-certification as you know how to describe your product, but also how to build your certification based on the included certified components. The current regulations will also need to be updated if more vehicles are to be self-certified, such as the Machine Directive.

Finally, we want to highlight the method used behind the conclusions. The project has been carried out as a policy lab where we have gathered different actors around a common challenge. In this way, we have anchored both the challenge of autonomous vehicles within the fenced area and on our conclusions in concrete details. The choice of method has also given relevant authorities the opportunity to familiarize themselves withhow they should relate to tomorrow´s technology without having to present a view on how they will relate to a specific test or vehicle going forward. In this way, Swedish authorities are ready to take on technical innovations once they are introduced to the market.

Systems of Systems is being applied in ever more complex contexts. This paper reports findings from a city logistics initiative. As many other environmental challenges, this setting can be characterized as 'wicked', e.g. the organizations that need to be involved solving the issues are contributing causes and there is no obvious single authority able to make decisions. Our findings suggest that such settings lead to vagueness and 'late binding' of key actors and incentives making the early modelling phases highly challenging. Supplementing the wave model of SoS development, we describe specific coping mechanisms for such settings including designing for multiple SoS archetypes and identifying and prioritizing archetype-generic capabilities. 

There have been a number of fires on board ro-ro ships with severe consequences the last decades, several which have started in a ro-ro space. To prevent and mitigate future fire accidents, cost-effective solutions to improve ships’ abilities to independently handle a fire starting in a ro-ro space are needed. Within the LASH FIRE project, innovative solutions aimed at strengthening the independent fire protection of ro-ro ships have been developed and demonstrated. These solutions are developed to strengthen all parts of the fire protection chain, from ignition prevention all the way to evacuation. This deliverable, D04.10, presents an overview of the testing and demonstration of the solutions. Through this deliverable, external parties, such as industry actors, will have a compilation of the evaluation and its outcome for the different solutions that have been developed and demonstrated within LASH FIRE.

Alkali metal-containing compounds are readily released during thermal conversion of solid fuels, and may have both detrimental and beneficial effects on chemical looping combustion. Here, we characterize alkali interactions with the inner walls of a laboratory-scale reactor under oxidizing, reducing and inert conditions at temperatures up to 900 °C. KCl aerosol particles are continuously introduced to the stainless steel reactor and the alkali concentration is measured on-line with a surface ionization detector. Aerosol particles evaporate at temperatures above 500 °C and KCl molecules rapidly diffuse to the reactor wall. Up to 92% of the alkali reaching the wall below 700 °C remains adsorbed, while re-evaporation is important at higher temperatures, where up to 74% remains adsorbed. Transient changes in alkali concentration are observed during repeated redox cycles, which are associated with changes in chemical composition of the wall material. Metal oxides on the reactor wall are partially depleted under reducing conditions, which allow for the formation of a new potassium-rich phase that is stable in a reducing atmosphere, but not under inert conditions. The observed wall effects are concluded to be extensive and include major transient effects depending on gas composition, and the implications for laboratory studies and improved experimental methodology are discussed. 

Chemical-Looping Combustion (CLC) of biofuels is a promising technology for cost-efficient CO2 separation and can lead to negative CO2 emissions when combined with carbon capture and storage. A potential challenge in developing CLC technology is the effects of alkali metal-containing compounds released during fuel conversion. This study investigates the interactions between alkali and an oxygen carrier (OC), CaMn0.775Ti0.125Mg0.1O3-δ, to better understand the fate of alkali in CLC. A laboratory-scale fluidized bed reactor is operated at 800–900 °C in oxidizing, reducing and inert atmospheres to mimic CLC conditions. Alkali is fed to the reactor as aerosol KCl particles, and alkali in the exhaust is measured online with a surface ionization detector. The alkali concentration changes with gas environment, temperature, and alkali loading, and the concentration profile has excellent reproducibility over repeated redox cycles. Alkali-OC interactions are dominated by alkali uptake under most conditions, except for a release during OC reduction. Uptake is significant during stable reducing conditions, and is limited under oxidizing conditions. The total uptake during a redox cycle is favored by a high alkali loading, while the influence of temperature is weak. The implications for the understanding of alkali behavior in CLC and further development are discussed. 

This paper aims to define the challenges and requirements necessary for the holistic management of wind turbine blades at the end of their service (EoS). Conducted within the Swedish research project Circublade, this study focuses on Sweden, although many challenges and findings are applicable to other countries. Various alternatives for managing EoS wind turbine blades exist at different levels of market maturity, but this paper specifically focuses on repurposing the blades into new products. The development of three concept designs—short-span pedestrian bridges, façade elements for building applications, and noise barriers for roads and railways—has been explored, along with aspects related to material sourcing, logistics, and implementation. For material sourcing, a digital platform containing blade data and tools to facilitate repurposing has been developed. An environmental evaluation of the different concepts highlights the significant impact of transportation on the overall environmental footprint, underscoring the necessity of a holistic approach to managing EoS blades.

System of systems (SoS) are intended to solve problems, provide more effective services, and enable greater collaborative behaviour. For SoS operating within the mobility domain, where the usefulness of the SoS solution largely depends on how many people will use the SoS, it is necessary to consider if there are potential gender aspects of the user that may negatively impact the SoS usefulness. In this study, we present the results from a literature survey on gender aspects of the usage of new mobility solutions and use this to present a conceptual model for how gender affects SoS mobility usage and how SoS stakeholders can act to impact this influence.The literature survey identified several gender aspects of using new mobility solutions. These aspects can significantly impact the usefulness and utilisation of SoS within the mobility domain. The conceptual model developed from the survey findings highlights the importance of considering gender in SoS mobility usage. By understanding how gender influences the usage of such SoS, stakeholders can take action to address any potential negative impacts. This model provides a framework for designing more inclusive and user-friendly SoS solutions that cater to the needs and preferences of all users, regardless of gender. 

Two approaches to modelling the effects of embedded defects and impact damage in composite aerostructures are presented. These differ in the manner in which the damage is represented; one as an equivalent delamination and the other as a soft inclusion with non-linear homogenized material properties. These techniques are applied to study the effects of defects and impact damage on the performance of composite panels.

Artificial Intelligence offers a wide variety of capabilities that can potentially address people's needs and desires in their specific contexts. This pilot study presents a collaborative method using a deck of AI cards tested with 58 production, AI, and information science students, and experts from an accessible media agency. The results suggest that, with the support of the method and AI cards, participants can ideate and reach conceptual AI solutions. Such conceptualisations can contribute to a more inclusive integration of AI solutions in society.

Novel IoT market solutions and research promise IoT modules that do not require  programming or electrical setup, yet shop floor personnel need to face problem solving  activities to create technical solutions. This paper introduces the Karakuri card deck and  presents a case study composed of four workshop sessions in four manufacturing settings,  where shop floor personnel tested the cards as a means of ideating and presenting  conceptual IoT solutions in the form of diagrams. The results indicate the validity of the  proposed conceptual solutions and suggest prototyping as a next step.

This paper presents a collaborative solution developed to enable people without prior Internet of Things (IoT) knowledge to ideate, conceptualise, role-play and prototype potential improvements to their work processes and environments. The solution, called the Karakuri IoT toolkit and method, was tested in two workshops with eight production leaders at a Swedish manufacturing company. Outcomes were analysed from the perspectives of materials interaction and instruments of inquiry. Results indicate the solution can help people conceive and prototype improvement ideas at early design stages. 

Heating of tap water makes up the lion share of the total energy used in the urban water cycle, up to 90 %. Estimates show that 780 to 1,150 kWh per person and year is used in Sweden for heating water. This energy mainly ends up in the sewers. Even if variations in energy use for this purpose are large and savings are possible, wastewater heat recovery, using heat exchangers or heat pumps, has a large potential.

Europe’s low-carbon energy policy favors a greater use of fuel cells and technologies based on hydrogen used as a fuel. Hydrogen delivered at the hydrogen refueling station must be compliant with requirements stated in different standards. Currently, the quality control process is performed by offline analysis of the hydrogen fuel. It is, however, beneficial to continuously monitor at least some of the contaminants onsite using chemical sensors. For hydrogen quality control with regard to contaminants, high sensitivity, integration parameters, and low cost are the most important requirements. In this study, we have reviewed the existing sensor technologies to detect contaminants in hydrogen, then discussed the implementation of sensors at a hydrogen refueling stations, described the state-of-art in protocols to perform assessment of these sensor technologies, and, finally, identified the gaps and needs in these areas. It was clear that sensors are not yet commercially available for all gaseous contaminants mentioned in ISO14687:2019. The development of standardized testing protocols is required to go hand in hand with the development of chemical sensors for this application following a similar approach to the one undertaken for air sensors. © 2021 by the authors. 

Renewable gases, hydrogen and biomethane can be used for the same applications as natural gas: to heat homes, power vehicles and generate electricity. They have the potential to contribute to the decarbonisation of the gas grid. Hydrogen blending with existing natural gas pipelines is also proposed as a means to increase the performance of renewable energy systems. Carbon capture and storage (CCS) and carbon capture and utilisation (CCU) technologies can be an answer to the global challenge of significantly reducing greenhouse gas emissions. Due to production methods, these gases typically contain species in trace amounts that can negatively impact the equipment they come into contact with or pipelines when injected into the gas grid. It is therefore necessary to ensure proper (and stable) gas quality that meets the requirements set out in the relevant standards. The gas quality standards require the collection and transport of a representative gas sample from the point of use to the analytical laboratory; i.e., no compounds may be added to or removed from the gas during sampling and transport. To obtain a representative sample, many challenges must be overcome. The biggest challenge is material compatibility and managing adsorption risks in the sampling systems (sampling line and sampling vessels). However, other challenges arise from the need for flow measurement with non-pure gases or from the nature of the matrix. Currently, there are no conclusive results of short-term stability measurements carried out under gas purity conditions (suitable pressure, matrix, appropriate concentrations, simultaneous presence of several species). © 2022, The Author(s).

The quality of the hydrogen delivered by refuelling stations is critical for end-users and society. The purity of the hydrogen dispensed at hydrogen refuelling points should comply with the technical specifications included in the ISO 14687:2019 and EN 17124:2022 standards. Once laboratories have set up methods, they need to verify their performances, for example through participation in interlaboratory comparisons. Due to the challenge associated with the production of stable reference materials and transport of these which are produced in hydrogen at high pressure (>10 bar), interlaboratory comparisons have been organized in different steps, with increasing extent. This study describes an inter-laboratory comparison exercise for hydrogen fuel involving a large number of participants (13 laboratories), completed in less than a year and included eight key contaminants of hydrogen fuel at level close to the ISO14687 threshold. These compounds were selected based on their high probability of occurrence or because they have been found in hydrogen fuel samples. For the results of the intercomparison, it appeared that fully complying with ISO 21087:2019 is still challenging for many participants and highlighted the importance of organising these types of exercises. Many laboratories performed corrective actions based on their results, which in turn significantly improved their performances. © 2024 The Author(s)

The International Convention for the Safety of Life at Sea (SOLAS) recognises five different fire-extinguishing system solutions for ro-ro spaces on ships; manually activated water spray systems (Resolution A.123(V)), automatic sprinkler or deluge water spray systems and automatic nozzle or deluge water mist systems (MSC.1/Circ.1430), high-expansion foam systems and gas fire-extinguishing systems (FSS Code). A review of potential commercially available alternative systems, their expected performance efficiency and water consumption was made. Based on this review, two alternative fire-extinguishing systems were identified: Compressed Air Foam Systems (CAFS) and foam-water sprinkler/spray systems. Fire suppression performance testing of water spray systems according to the Resolution A.123(V) and MSC.1/Circ.1430, a CAFS and a foam-water spray system were conducted. The water spray system per MSC.1/Circ.1430 had superior performance while the system per Resolution A.123(V) and the foam-water spray system limited the fire size to some degrees. The CAFS provided limited fire suppression performance.

Closed ro-ro spaces on maritime vehicle carriers are usually protected by a total-flooding carbon dioxide system. Such systems have many benefits, for example that there are no residues that can adversely affect the protected objects (in this case thousands of vehicles) and the agent is electrically non-conductive. However, there could be a considerable time delay from the start of a fire until the carbon dioxide system is discharged. Experience has shown that this delay time can cause significant fire damage and jeopardize the performance of the system. Within the EU funded LASH FIRE project, design and installation guidelines for supplementary automatic water-based fire sprinkler systems were developed. An important design feature is that the system automatically activates at an early stage of a fire. This would allow more time to fight the fire manually or to safely evacuate the space and discharge the CO2 system when the fire is controlled to one or a few vehicles instead of at a time when it has escalated in size. The work was partly based on a comprehensive literature review that identified relevant standards and information applicable to the design of automatic fire sprinkler and deluge water spray systems. Large-scale fire tests verified that the suggested system designs were able to provide control of realistic vehicle fires, including fires in passenger cars and a freight truck.