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1.	Ajeel, Raheem K., et al. (author) Comprehensive analysis of heat transfer and pressure drop in square multiple impingement jets employing innovative hybrid nanofluids 2024 In: Results in Engineering (RINENG). - : Elsevier B.V.. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract This study presents a comprehensive analysis of heat transfer and pressure drop characteristics in square multiple impingement jets utilising a novel class of hybrid nanofluids. This study goes beyond the usual vertical impingement method by looking at the use of oblique impingement in a multiple impinging jet configuration with a hybrid nanofluid. Al2O3–Cu/water with different volume fractions () such as 0.1%, 0.33%, 0.75%, and 1.0% are employed as a working fluid. The purpose of the study is to clarify the impact of the jet angle (β), the jet Reynolds number (Re), extended jet height ), and different volume fraction () on the heat transfer behaviours of the curved target surface. The jet Reynolds number varies from 8000 to 24,000, and five different jet angles (β = 15 , 30°, 45°, 60°, 90 ) and three extended jet heights = 0.2H, 0.4H, and 0.6H) are adopted. Outcomes disclosed that the highest values of Re and greatly led to an increase in heat transfer rate and pressure drop of the system. It is uncovered that the heat transfer rate of binary hybrid nanofluids enhances with increasing volume fraction from for all jet angles and Re. Results also exposed that the angle of jet, which is 45°, gives a higher Nusselt number compared to other angles proposed in this study, and the maximum boost reaches 35%. Besides, despite the fact that reducing the height of the extended jet yields enhanced heat transfer rates in comparison to other methods, it concurrently results in an elevation in pressure drop. Finally, this research yielding insights that can be applied to improve the efficiency of heat transfer systems in practical applications.
2.	Alharthai, Mohammad, et al. (author) Numerical study on enhancing shear performance of RC beams with external aluminum alloy plates bonded using steel anchors 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 22 Journal article (peer-reviewed)abstract This article compromises a three-dimensional numerical study employing the Abaqus program to investigate the behavior of reinforced concrete (RC) beams externally strengthened in shear using aluminum alloy (AA) plates bonded utilizing steel anchors. Based on previous experimental tests, a numerical validation study was conducted in two parts. The first part modeled the interaction behavior using different bonding methods between steel plates and the surface of the RC beams, whether utilizing epoxy adhesive only, steel anchors only, or a dual system between them. The second part modeled the performance of shear-defected RC beams that externally strengthened by the AA plates using epoxy adhesive. To take into account debonding collapse due to epoxy adhesive bonding, the interaction between the AA plates and beam surface was simulated with a cohesive-damage interaction. Comparing the numerical results with previous experimental studies shows the success of the numerical model in simulating the performance of different bonding methods, as well as the behavior of the RC beams defected in shear and strengthened by the AA plates, which qualified it to study some additional variables. From the study it was found that by utilizing only epoxy adhesive, the strengthening technique using the AA plate over the entire shear span zone (AASP method) was capable of increasing the ultimate capacity of the defected beam by 104%, which represents 77% of the load of the non-defected beam. It was also demonstrated that the AA plates were susceptible to collapse by the out-of-plane buckling when bonded using the steel anchors only. By utilizing a dual system for bonding the AA plates consisting of epoxy adhesive and steel anchors, the AASP method was capable of enhancing the ultimate capacity of the defected beam by 164% and changing its failure pattern to the preferred ductile bending pattern.
3.	Amran, Mugahed, et al. (author) Shrinkage mitigation in alkali-activated composites: A comprehensive insight into the potential applications for sustainable construction 2023 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 20 Research review (peer-reviewed)abstract The extant body of literature articulates a noticeable disparity in the susceptibility to cracking and concomitant material degradation between alkali-activated composites (AAC) and ordinary Portland cement (OPC), predominantly attributable to shrinkage and subsequent drying phenomena. This divergence derives from the nanoscopic porosity of AAC binders, which is substantially finer than their OPC counterparts. However, experimental research validates that the judicious incorporation of alternative cementitious materials and fibrous reinforcements enriches the shrinkage characteristics of AAC, thereby enhancing its overall structural performance. Given the crucial role of shrinkage in defining the material integrity of AAC, especially under constrained environmental conditions, an in-depth understanding of shrinkage mechanisms materializes as a necessity for conceiving efficient shrinkage-mitigating strategies. In light of the growing interest in optimizing AAC through various material integrations and methodological innovations aimed at shrinkage diminution, this scholarly review undertakes an extensive synthesis of the laboratorial investigations focused on AAC shrinkage behavior and mitigation. However, this article critically evaluates widespread strategies for shrinkage mitigation, explicating their operative mechanisms. Moreover, it is outlined gaps in the existing research paradigm, promoting for targeted scholarly endeavors to yield a more clear understanding of shrinkage dynamics and to facilitate the advancement of environmentally sustainable AAC composites. Meanwhile, this study intended to consolidate existing research on developing trends in order to gain a comprehensive understanding of the possible uses of AACs and identify viable strategies for addressing AAC shrinkages. By addressing the challenges related to micro-cracking and shrinkage, the long-term durability of AACs may be improved, leading to increased adoption of these materials as sustainable building options in the construction industry today.
4.	Awoyera, Paul O., et al. (author) Structural performance of fire-damaged concrete beams retrofitted using bamboo fiber laminates 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract Fire-induced damage is a serious threat to the structural integrity of reinforced concrete (RC) beams, necessitating an effective retrofitting strategy to restore and improve their performance. This study investigates the structural performance of fire-damaged RC beams retrofitted with bamboo fiber laminates. A comprehensive analysis was performed, incorporating degradation rules to quantify the effect of temperature on both the load-carrying capacity and ultimate deflection of the RC beams. Eight conventionally designed and reinforced RC beams were tested, with two serving as controls. The remaining six beams were tested in pairs at three different temperatures (400 ◦C, 600 ◦C, and 800 ◦C) for 2-h exposure, with one beam featuring the bamboo fiber laminates in each pair. The bamboo fiber laminates enhanced the load-carrying capacity and deflection of the fire-damaged beams when subjected to incremental loading until failure. The deflection was improved by 48.78% at 400 ◦C, restoring the load-carrying capacity to control levels. The load-carrying capacity was increased by 29.5% at 600 ◦C, while the deflection was restored by 39.37%. The load-carrying capacity was enhanced by 37% at 800 ◦C, while the deflection was improved by 4.83%. According to the findings, bamboo fiber laminate is a viable alternative to synthetic fibers for retrofitting fire-damaged beams.
5.	Cehlin, Mathias, Doktor, 1974-, et al. (author) Towards benchmarking of urban air quality based on homogenous surface emission 2023 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 20 Journal article (peer-reviewed)abstract Here, it is presented a possible methodology and experimental model for benchmarking of air quality in cities. The concept behind the methodology is that a city’s inherent structure affects the potential for contaminant removal due to the resistance it poses to inflow. The approach is based on homogenous emission across the street surface network, representing a worst-case situation. Different levels of complexity can be used for benchmarking, making it valuable for evaluating different layouts. Additionally, an urban ventilation index suitable for these kinds of experimental studies has been suggested.
6.	Chanda Nagarajan, Pratheeba, 1978, et al. (author) Turbulent uniformity fluctuations in automotive catalysts – A RANS vs DES assessment 2022 In: Results in Engineering. - : Elsevier BV. - 2590-1230. ; 16 Journal article (peer-reviewed)abstract Attaining sufficient flow uniformity in catalytic aftertreatment systems is a major challenge for the automotive industry. Computational fluid dynamics (CFD) simulations offer means of analyzing and quantifying this flow uniformity in silico. In this work, predictions from numerical simulations of flow uniformity obtained using a conventional steady-state Reynolds-Averaged Navier-Stokes (RANS) approach are contrasted against comprehensive Detached Eddy Simulations (DES) where the large-scale turbulence is resolved in space and time. It is shown that the DES approach provides access to data on flow uniformity fluctuations that could be significant for the catalyst light-off behavior. However, the computational cost of the DES is approximately three orders of magnitude larger than that of the corresponding RANS simulation.
7.	Dehsorkhi, Soha, et al. (author) Low turn-on voltage of doped organic light emitting diodes based on food dyes 2020 In: Results in Engineering. - : Elsevier. - 2590-1230. ; 5, s. 1-10 Journal article (peer-reviewed)abstract Three derivatives of food azo dye were investigated (Dyes 1, 2 and 4) by theoretical and experimental tools. Photophysical properties, based on theoretical estimations, experimental evaluations, electrochemical and photoelectrical properties were discussed. The compounds exhibited efficient emission of solid state with maximum fluorescence intensity at the range of 517–646 nm and PLQY (photoluminescence quantum yield) values at the range of 9–17% in non-doped solid state and 13–39% in doped solid state. In this study 90 wt percent of PBD (2-(4-tert-Butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole) have been used as the electron transporting host who derived balanced charge carrier transport for high internal and external efficiency of OLEDs (organic light emitting diodes). Ionization potential for compounds was found to be comparable (5.85 and 6.18 eV) by photoelectron emission spectrometry. According to the fabrication of devices for gaining charge mobility the layers of the dyes showed properties as a bipolar charge transporting with balanced hole and electron mobility and the values reaching to 1.27 × 10−4 cm2/Vs and 1.09 × 10−4 cm2/Vs respectively at high electric fields. Furthermore, OLEDs consist of azo dyes as an emitter layer fabricated by PVD (physical evaporation deposition) method and the maximum values of the best device showed, consist of, the low turn on voltage of 2.69 V and values of brightness, current efficiency, power efficiency, EQE (external quantum efficiency) 16432.40 cd/m2, 8.20 cd/A, 6.95 lm/w, 4.89% respectively.
8.	Duryodhana, D., et al. (author) Buckling and free vibrations behaviour through differential quadrature method for foamed composites 2023 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 17 Journal article (peer-reviewed)abstract The current work focuses on predicting the buckling and free vibration frequencies (fn) of cenosphere reinforced epoxy based syntactic foam beam under varying loads. Critical buckling loads (Ncr) and fn are predicted using the differential quadrature method (DQM). Ncr and fn have been calculated for beams of varying cenosphere volume fractions subjected to axial load under clamped-clamped (CC), clamped-simply (CS), simply-simply (SS), and clamped-free (CF) boundary conditions (BC′s). Upon increasing the cenosphere volume fraction, Ncr and fn of syntactic foam composites increases. These numerical outcomes are compared with the theoretical values evaluated through the Euler-Bernoulli hypothesis and further compared with experimental outcomes. Results are observed to be in precise agreement. The results of the DQM numerical analysis are given out for the different BC′s, aspect ratios, cenosphere volume fractions, and varying loads. It is perceived that depending on the BC′s, the type of axial varying loads and aspect ratios has a substantial effect on the Ncr and fn behaviour of the syntactic foam beams. A comparative study of the obtained results showed that the beam subjected to parabolic load under CC boundary conditions exhibited a higher buckling load. © 2023 The Authors
9.	Forsberg, Samuel, et al. (author) Resilience to extreme storm conditions : A comparative study of two power systems with varying dependencies on offshore wind 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 23 Journal article (peer-reviewed)abstract In the next decades, the dependencies on power production from renewable energy sources are expected to increase dramatically. A transition towards large-scale offshore wind farms together with an increased electrification of the industry and transportation sectors introduces new vulnerabilities to society. Further, extreme weather events are expected to increase in intensity and frequency, driven by climate change. However, there are significant knowledge gaps concerning the impacts of severe weather conditions on the resilience of power systems with large dependencies on offshore wind. In the present study, a comparison between two different power systems’ resilience to historical extreme storm conditions has been conducted. The power systems are the IEEE39-bus New England model and the Great Britain model. The results show significant differences between the two power systems, which underlying reasons are analysed and explained. With an offshore wind penetration level of 30 %, the New England model stays intact in terms of connected load. When increasing the penetration level to 40 %, about 10 % of the total connected load gets disconnected, whereas about 33 % of the load gets disconnected with a penetration level of 50 %. The Great Britain model stays intact in terms of connected load with a penetration level of at least 49 %.
10.	Hauashdh, Ali, et al. (author) An integrated framework for sustainable and efficient building maintenance operations aligning with climate change, SDGs, and emerging technology 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract While existing literature offers various frameworks, they primarily focus on traditional building maintenance procedures and overlook the importance of integrating sustainability, climate change, environmental factors, and emerging technologies. To address this gap, this research has developed a comprehensive framework that caters to current needs, challenges, and future priorities. The integrated framework for building maintenance operations aligns with the Sustainable Development Goals (SDGs), climate change mitigation and adaptation, the adoption of emerging technology, energy conservation, as well as safety, resilience, and effectiveness. The development of the framework encompassed four phases: pre-development phases 1 and 2, development phase 3, and validation phase 4. During this process, current issues and challenges were identified, impacts were assessed, and strategies were developed. The framework serves as a roadmap to address these challenges and requirements in future building maintenance operations, making significant contributions to all three dimensions of sustainability: environmental, social, and economic. In summary, this study offers a comprehensive and in-depth analysis of the current issues, challenges, and potential improvements and benefits in building maintenance operations, providing a practical guide for industry stakeholders and making a significant contribution to the existing body of knowledge.
11.	Hjelm, Rikard, et al. (author) A multi-perspective method for gear efficiency and contact analysis 2023 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 20 Journal article (peer-reviewed)abstract Modern gearing applications, in particular electrification, impose new challenges in many different fields of engineering and research. In specific, new demands are imposed on gears, including higher rotational speed, lower noise acceptance, and increased efficiency, as well as increased resistance against pitting and scuffing. To meet these demands, a better understanding of gear contacts is needed. The Eurostars project Effigears proposes a novel multi-perspective methodology for assessment of gear efficiency and contact analysis. The methodology consists of using a novel surface treatment method, Triboconditioning (R), implemented in a streamfinishing process, surface measurements using a scattered light method, experimental testing using the standardized FZG test rig, and contact simulations using a novel thermal elasto-hydrodynamic lubrication tool. It is found, in preliminary tests, that enhanced gear performance may be enhanced due to Triboconditioning (R) surface treat-ment. Findings also include better understanding of how surface characteristics and lubricants affect scuffing and pitting, and the effect of load distribution on gearset behavior.
12.	Hjelm, R., et al. (author) Gear tolerancing for simultaneous optimization of transmission error and contact pressure 2021 In: Results in Engineering. - : Elsevier BV. - 2590-1230. ; 9 Journal article (peer-reviewed)abstract With electrification of vehicles comes an increasing demand on low noise, which for gears translates to transmission error. In this paper, static transmission error, STE, is found for a large number of manufacturing error combinations belonging to different tolerance classes, with focus on those typically used in the automotive industry. There is a lack of studies found in the scientific literature which investigate the link between STE, contact pressure, and manufacturing error tolerances. Therefore, the aim of the present study is to investigate this link. This is done by utilizing a novel simulation tool, developed by the authors, to compute STE for gear sets with pitch and profile slope errors combinations. The model uses a parametric description of the reference profile, includes tooth modifications, uses a hybrid method for compliance, and finds contact from equilibrium. The model handles contact outside the nominal line of action, including tip contact. A simplified method, with predictions based on simulated values, is shown to be accurate and suitable for estimations. Finally, STE is linked to contact pressure for better understanding of how STE and contact pressure interact as a consequence of manufacturing errors. It is shown how this can be used to optimize the gear set with respect to both STE and contact pressure simultaneously.
13.	Isleem, Haytham F., et al. (author) Nonlinear finite element and analytical modelling of reinforced concrete filled steel tube columns under axial compression loading 2023 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 19 Journal article (peer-reviewed)abstract Local buckling of steel and excessive spalling of concrete have necessitated the need for the evaluation of reinforced concrete columns subjected to axial compression loading. Thus, this study investigates the behaviour of concrete filled steel tube (CFST) columns and reinforced concrete filled steel tube (RCFST) columns under the axial compression using the finite element modelling and machine learning (ML) techniques. To achieve this aim, a total of 85 columns from existing studies were analysed utilising the finite element modelling. The ultimate load of the generated datasets was predicted employing various ML techniques. The findings showed that the columns’ compressive strength, ductility, and toughness were improved by reducing transverse reinforcement spacing, increasing the number of reinforcing bars, and increasing the thickness and yield strength of outer steel tube. Under the axial compression loading, the finite element modelling analysis provided an accurate assessment of the structural performance of the RCFST columns. Compared to other ML approaches, gradient boosting exhibited the best performance metrics with R2 and root mean square error values of 99.925% and 0.00708 and 99.863% and 0.00717 respectively in training and testing stages, to predict the columns’ ultimate load. Overall, gradient boosting can be applied in the ultimate load prediction of CFST and RCFST columns under the axial compression, conserving resources, time, and cost in the investigation of the ultimate load of columns through laboratory testing.
14.	Jareteg, Adam, 1989, et al. (author) Effects of bed aging on temperature signals from fixed-bed adsorbers during industrial operation 2020 In: Results in Engineering. - : Elsevier BV. - 2590-1230. ; 8 Journal article (peer-reviewed)abstract The capacity of adsorber beds used in industrial-scale temperature-swing adsorption diminishes over time due to bed aging. Here, we present industrial data on the temperature signals from fixed-bed adsorbers using activated carbon designed to remove benzene and other impurities from the gas produced in biomass gasification. The aging of the adsorber beds proceeds due to irreversible adsorption of trace species and manifests itself via two simultaneous effects: a decrease in the availability of active adsorption sites over time and an increase in the overall thermal mass of the bed. Both effects tend to dampen the temperature response of the beds during operation, implying that they are easily confounded. Model descriptions of bed aging should account for both effects.
15.	Karnama, A., et al. (author) Organic data centers : A sustainable solution for computing facilities 2019 In: Results in Engineering. - : Elsevier B.V.. - 2590-1230. ; 4 Journal article (peer-reviewed)abstract In the present perspective article we provide an overview of on-going work in the literature and possible future development of organic data centers (ODC). These are defined as the combined operation of a data center and a greenhouse, and given their compatible thermal and operation requirements, ODCs have the potential to provide an excellent solution in terms of sustainability. In particular, we identify possible positive impacts of ODCs on at least 5 of the 17 United Nations (UN) Sustainable Development Goals (SDGs), including SDGs 2 and 13 on zero hunger and climate change, respectively.
16.	Khan, Majid, et al. (author) Forecasting the strength of graphene nanoparticles-reinforced cementitious composites using ensemble learning algorithms 2024 In: Results in Engineering (RINENG). - : Elsevier B.V.. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract Integrating nanomaterials into concrete is a promising solution to improve concrete strength and durability. However, the intricacies of such nanoscale cementitious composites are highly complex. Traditional regression models encounter limitations in capturing these intricate compositions to provide accurate and reliable estimations. This study focuses on developing robust prediction models for the compressive strength (CS) of graphene nanoparticle-reinforced cementitious composites (GrNCC) through machine learning (ML) algorithms. Three ML models, bagging regressor (BR), decision tree (DT), and AdaBoost regressor (AR), were employed to predict CS based on a comprehensive dataset of 172 experimental values. Seven input parameters, including graphite nanoparticle (GrN) diameter, water-to-cement ratio (wc), GrN content (GC), ultrasonication (US), sand content (SC), curing age (CA), and GrN thickness (GT), were considered. The models were trained with 70 % of the data, and the remaining 30 % of the data was used for testing the models. Statistical metrics such as mean absolute error (MAE), root mean square error (RMSE) and correlation coefficient (R) were employed to assess the predictive accuracy of the models. The DT and AR models demonstrated exceptional accuracy, yielding high correlation coefficients of 0.983 and 0.979 for training, and 0.873 and 0.822 for testing, respectively. Shapley Additive exPlanation (SHAP) analysis highlighted the influential role of curing age and GrN thickness (GT), positively impacting CS, while an increased water-to-cement ratio (w/c) negatively affected CS. This study showcases the efficacy of ML techniques in accurately predicting CS of graphene nanoparticle-modified concrete, offering a swift and cost-effective approach for assessing nanomaterial impact on concrete strength and reducing reliance on time-consuming and expensive experiments.
17.	McPherson, Guy R., et al. (author) Environmental thresholds for mass-extinction events 2022 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 13 Journal article (peer-reviewed)abstract While the global-average temperatures are rapidly rising, more researchers have been shifting their focus towards the past mass-extinction events in order to show the relations between temperature increase and temperature thresholds which might trigger extinction of species. These temperature and mass-extinction relation graphs are found practical by conservationists and policy makers to determine temperature threshold values to set climate targets. Unfortunately, this approach might be dangerous, because mass-extinction events (MEEs) are related to many environmental parameters and temperature is only one of them. Herein we provide a more comprehensive evaluation of the environmental thresholds required to sustain a habitable planet. Besides, we suggest actions within the sustainable-development goals (SDGs) to observe those critical environmental parameters, in order to assure having an inhabitable planet for the current living species.
18.	McPherson, Guy R., et al. (author) The commonly overlooked environmental tipping points 2023 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 18, s. 101118- Journal article (peer-reviewed)abstract Climate models are developed based on well-established physical principles applied to past and recent climate changes. There is considerable confidence that the models can also provide estimates of some climate variables (i.e., surface temperature, CO2 levels, ocean heat content). Despite advanced mathematical developments in the field of climate modeling, the existing climate models suffer from the following major limitations: first, the models do not consider that their estimations will be highly unreliable when a tipping point is triggered; secondly, many of the environmental tipping points are already triggered, however their existence is overlooked; and third, the existing climate models do not consider the interrelations among the tipping points (i.e., one tipping point can trigger other tipping points to be tipped more rapidly). Our objective is to describe the importance of environmental "tipping points," the importance of which is often ignored or downplayed in relevant literature. Our analysis, based on extensive multidisciplinary literature searches, reveals that there are many environmental tipping points which are overlooked in climate-modeling studies. We argue that climate modeling could be improved when the tipping points and their interrelations are all considered within the modeling process. We further discuss two other important issues regarding environmental tipping points: first, all tipping points might not be as impactful on the climate system, therefore their relative impacts should be ranked; second, it is in principle impossible to know the exact number of environmental tipping points, therefore even though it could be possible to devise improvements to the existing climate models with our suggestions, it may be impossible to achieve a perfect model to estimate the climate variables of the upcoming years. The remainder of this paper is structured as follows: In the background section, we introduce research on tipping points within commonly used climate models. We explain the aerosol masking effect and ocean dynamics with respect to their commonly overlooked roles as important contributors to environmental change. We introduce remote sensing and AI methods that serve as promising approaches for identification of currently unknown tipping points. We mention perturbation theory, a standard set of mathematical methods in physics that serves as a potentially systematic method to rank environmental tipping points according to their impact on extant climate models. In the discussion section, we make suggestions regarding further research on identifying the typically overlooked tipping points, and we make suggestions to improve climate models by considering additional information presented in the current paper. Finally, we conclude this article summarizing our chief methodological recommendations.
19.	Nadeem, Muhammad, et al. (author) Evaluation of mechanical properties of cored interlocking blocks – A step toward affordable masonry material 2023 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 18 Journal article (peer-reviewed)abstract This research study is about the evaluation of mechanical properties of locally prepared Cored 6” self-interlocking blocks. Currently, all the construction practices, whether brick masonry, block masonry, or reinforced concrete, are time consuming, relatively energy inefficient, not eco-friendly, and non-sustainable. Another issue in masonry construction is that the strength and behavior of bricks or blocks masonry depend upon the properties of the binding material (mortar) used in masonry wall joints. Considering these issues, Eco Blocks are newly introduced interlocking blocks with different sizes and shapes. Construction with interlocking blocks is faster, economical, and easier, as they do not require binding material. The aim of this study was to obtain the mechanical properties such as the compressive strength (individual block and prism), diagonal tensile strength, shear parameters, modulus of elasticity, shear modulus, and flexural strength of Cored 6′′ Eco Blocks through comprehensive experimental investigation. These showed encouraging results as compared with typical interlocking compressed earth blocks and also satisfied the threshold set forth by the international standards regulating earth construction. The compressive and flexural strengths of the blocks have been obtained as 6.03 MPa and 1.66 MPa, respectively. Based on the results outcomes, Cored 6” Eco Blocks can be utilized in load bearing walls.
20.	Neelam, R., et al. (author) Mechanical response of additively manufactured foam : A machine learning approach 2022 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 16 Journal article (peer-reviewed)abstract This paper uses ensemble and automated machine learning algorithms to predict the mechanical properties (tensile and flexural strength) of a three-dimensionally printed (3DP) foamed structure. The closed cell foams were made from the most commonly used thermoplastic, High-Density Polyethylene (HDPE). The hollow glass microspheres are infused in HDPE at varying volume %. The available data on these foams' mechanical properties are used by the chosen machine learning (ML) algorithms to propose the best suited algorithm for such a three-phased microstructure as these closed cell foams exhibit. Finally, the strength predictions from the models were validated using experimental data. The models were trained with nozzle temperature, bed temperature, and force values as input parameters. The output parameters predicted were the tensile and flexural strength. LightGBM outperforms all other models in terms of performance among ensemble-based models, while H2OAutoML outperforms all other models. All the ML algorithms produced models with greater than 95% accuracy. Finally, memory and time consumption for each model are presented. © 2022 The Authors
21.	Nouri, Leila, et al. (author) Hydrological responses to future climate change in semi-arid region of Iran (Golabar and Taham Basins, Zanjan Province) 2024 In: Results in Engineering. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract One of the most challenging and warning issues that have globally been introduced is the climate change and its effects on water resources. Climate change due to global warming has increased temperature and evaporation potential and has changed the precipitation pattern as well as precipitation amount in different seasons. The aim of this study is to assess the impact of climate change on the hydrological response of the basins of Golabar and Taham (in Zanjan province, Iran) in two future periods 2020–2030 and 2046–2065.10 different Global Climate Models (GCM) were analyzed to introduce novel selected model for future climate projections. The future climate parameters were simulated using the best climate model under the A1B and B1 emission scenarios. Two pessimistic and optimistic future climatic scenarios were defined based on the worst and the most desirable climate condition (using the temperature and precipitation data). The results showed that in the pessimistic scenario, the average annual temperature will rise 1.77 °C and 2.19 °C in Golabar and Taham basins, respectively. For the annual precipitation, reduction of 6.49 and 3.75 percent is shown for the Golabar and Taham basins, respectively. Also, in the average annual river flow, Golabar and Taham basins will experience a decrease of more than 25 percent in the future period (2046–2065). In the optimistic scenario, Golabar and Taham basins will experience 0.29 °C and 0.51 °C increase in the average annual temperature, respectively. In the annual precipitation, 3.6 and 7.01 percent increase is shown for the Golabar and Taham basins, respectively. In the average annual river flow, an increase of 7 % and 15 % would be expected in the future period (2020–2030) for the Golabar and the Taham basins, respectively.
22.	Nourozi, Behrouz, 1986-, et al. (author) Heating energy implications of utilizing gas-phase air cleaners in buildings’ centralized air handling units 2022 In: Results in Engineering (RINENG). - : Elsevier B.V.. - 2590-1230. ; 16 Journal article (peer-reviewed)abstract Ventilation systems are a vital component of buildings in order to ensure a healthy and comfortable environment for the occupants. In cold climate regions, ventilation systems are responsible for approximately 30% of building heat losses. In addition to outdoor pollutants (particulate matters, NOX, etc.), indoor emissions from materials in the form of gas pollutants and emissions from occupants are the principal indoor air quality metrics for securing an acceptable indoor concentration level. Therefore, it is of great interest to study the use of gas-phase air cleaning technologies in low-energy centralized air handling units. This study focused on reducing buildings' heating requirements by recirculating indoor air while maintaining an acceptable indoor air quality level. The heating performance of a typical residential and office building in the central Swedish climate was studied by dynamic building simulations. Indoor air recirculation rates and air changes per hour were the key parameters considered during the simulation of the building's heating demand and indoor gaseous air pollution concentration. We found that introducing indoor air recirculation reduces buildings' heating demand depending on the air change rates per hour. The results show that it is possible to reduce the energy use for heating by less than approximaytely 10% and 20% for residential and office buildings, respectively and maintain acceptable indoor air quality by using gas-phase air cleaning.
23.	Razmi, Nasrin, et al. (author) Monitoring the effect of pH on the growth of pathogenic bacteria using electrical impedance spectroscopy 2023 In: Results in Engineering (RINENG). - : ELSEVIER. - 2590-1230. ; 20 Journal article (peer-reviewed)abstract pH value is a significant environmental factor controlling the bacterial growth, activity and affecting their metabolic properties. In the present study, the effect of the different pH values (5, 6, 7, 8, and 9) of the cultivation medium on the growth rate of Escherichia coli ATCC 8739, Bacillus cereus ATCC 10876 and Pseudomonas aeruginosa 134,909/2 were studied. Plate count method and spectrophotometric measurement of optical density of the cultivation broth were used to assess growth of the pathogenic bacteria. Moreover, impedance spectroscopy measurement was applied to monitor the impedance change caused by the bacterial growth and activity at different pH values. Although the results showed that the initial pH did not completely inhibit the growth of the bacteria, the bacterial growth varied with the pH change showing the interference of pH with cell metabolism. Based on the results, the optical density of the cultivation broth measured spectrophotometrically for E. coli and B. cereus has shown good correlation with cell number determined by the plate count method in each phase of bacterial cultivation. Moreover, the results indicated that for E. coli and B. cereus the impedance value of the bacteria and the medium decreased from the beginning of the experiment till its end after 96 h from the start The impedance value during the first 24 h increased for P. aeruginosa, and then was decreasing until the end of the experiment. Nevertheless, the change in the resistance of the bacteria and the medium was proportionate to the change in cell number. For E. coli and B. cereus the resistance was decreasing with the growth of the bacteria. The linear dependency between the impedance and cell number was observed at low frequencies around 10-100 Hz. For P. aeruginosa, the resistance was increasing during the first 24 h and was decreasing afterwards. Furthermore, the resistance for P. aeruginosa was decreasing with the increase in cell number. Nonetheless, the impedance of the medium with P. aeruginosa was in linear dependency on the logarithm of cell number with the best R2 at high frequencies (0.1-1 MHz).
24.	Risberg, Mikael, et al. (author) Experimental investigation of a crawl space located in a sub-arctic climate 2020 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 7 Journal article (peer-reviewed)abstract A common type of foundation for family houses in Northern countries is crawl spaces, where mould and moisture are a common problem for a large share of these. In this study, measurement in a crawl space located in a subarctic climate has been performed for over a year. Calculation and prediction of the climate inside the crawl space are performed both for the experimental case with a dehumidifier and a theoretical case without a dehumidifier. The results show that it is not necessary to measure at several points in the crawl space since the difference between the measurement points is small. The relative humidity is below the critical in the investigated crawl space during the whole year when a dehumidifier is used and therefore is no risk for mould growth. Prediction for a naturally ventilated crawl space with ACR of 1.5 shows that mould index will reach almost four and very close not to reach zero between different years, which indicates that mould index could start to increase between the years and cause problems.
25.	Risberg, Mikael, et al. (author) Numerical calculation of heat losses for crawl space foundation at different locations in Sweden 2020 In: Results in Engineering. - : Elsevier. - 2590-1230. ; 7 Journal article (peer-reviewed)abstract Crawl space is one of the most common foundation types in Sweden, and over five hundred thousand family houses have this type of foundation. This study determines how the heat losses variate at six different locations in Sweden from the south to the north. The average heat for a year varied between 1.76 and 3.07 W/m2. The maximum heat flux was 4.43 W/m2 in Kiruna, while Falsterbo has a maximum heat flux of 3.18 W/m2. Minimum heat flux varied between 0.43 and 1.38 W/m2. A sensitivity study of the important parameter showed that the temperature is the most important parameter with a decrease in average heat flux of 0.15 W/m2 per degree increase in air temperature. Snow depth and snow days are less sensitive and give less than a 2.3% decrease for the average heat flux with a variation of ±50% and ±20 days, respectively.
26.	Rosenberg, Emelie, et al. (author) Sentiment analysis on Twitter data towards climate action 2023 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 19 Journal article (peer-reviewed)abstract Understanding the progress of the Sustainable Development Goals (SDGs) proposed by the United Nations (UN) is important, but difficult. In particular, policymakers would need to understand the sentiment within the public regarding challenges associated with climate change. With this in mind and the rise of social media, this work focuses on the task of uncovering the sentiment of Twitter users concerning climate-related issues. This is done by applying modern natural-language-processing (NLP) methods, i.e. VADER, TextBlob, and BERT, to estimate the sentiment of a gathered dataset based on climate-change keywords. A transfer-learning-based model applied to a pre-trained BERT model for embedding and tokenizing with logistic regression for sentiment classification outperformed the rule-based methods VADER and TextBlob; based on our analysis, the proposed approach led to the highest accuracy: 69%. The collected data contained significant noise, especially from the keyword 'energy'. Consequently, using more specific keywords would improve the results. The use of other methods, like BERTweet, would also increase the accuracy of the model. The overall sentiment in the analyzed data was positive. The distribution of the positive, neutral, and negative sentiments was very similar in the different SDGs.
27.	Sahil, Mehran, et al. (author) Seismic performance evaluation of exterior reinforced concrete beam-column connections retrofitted with economical perforated steel haunches 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 22 Journal article (peer-reviewed)abstract The exterior beam-column joint (BCJ) within reinforced concrete (RC) frame structures is acknowledged as a vulnerable component prone to seismic failure. This article proposes a practical and economical strengthening method for exterior BCJs using a perforated steel haunch system. This method is designed to mitigate damage in BCJs and improve the seismic performance of the structure. Employing finite element modeling (FEM) techniques, the study evaluates the impact of perforated steel haunches on the BCJs’ behavior and performance. The investigation involves creating nine distinct models, each representing a BCJ with a steel haunch system. These models include a control model without any perforations and eight variations with different levels of perforation (ranging from 10% to 50%) within the steel haunch system. Furthermore, the study analyzes the influence of perforation shapes on the connections’ performance, considering square, circular, hexagonal, and triangular shapes. The results reveal that utilizing a steel haunch without perforations significantly increases the load-carrying capacity of a BCJ by about 89%. Additionally, circular or square-shaped perforations, up to 30–35% within the steel haunch, effectively prevent the joints’ failure and promote the ductile behavior. These findings hold the potential to advance the design methodology for RC joints subjected to seismic loads, thereby enhancing the structural resilience in earthquake-prone regions.
28.	Saini, P., et al. (author) Performance evaluation of a parabolic trough collector with a uniform helical wire coil flow insert 2024 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 21 Journal article (peer-reviewed)abstract Solar energy is an extremely useful and dependable renewable energy source for meeting our society's diverse energy demands. Solar concentrator-based energy systems are currently the most efficient methods of using solar energy. Among these technologies, the parabolic trough collector is a mature and effective concentrating solar power technology with a wide range of real-world applications using solar alone or in combination with other energy sources. Flow insert is a potential approach for improving parabolic trough solar collector performance through enhanced heat transfer and heat absorption. The purpose of this study is to determine the feasibility of using a uniform helical wire coil flow insert in the LS-2 parabolic trough solar collector module. A computational fluid dynamic model developed in Ansys 18.1 is used in the current investigation. A uniform helical wire coil flow insert is modeled and compared with the plain tube without any insert inside it. Flow analysis, overall efficiency, exergy efficiency, and thermal efficiency are compared in the evaluation process. The overall efficiency and exergy efficiency of the parabolic trough collector are the most critical criteria in determining its performance. The parabolic trough collector is examined using a range of inlet fluid temperatures ranging from 303 K to 603 K and a volumetric flow rate of 50 L per minute to 250 L per minute. The pumping work is found to be the lowest, indicating that the increase in pressure drop has a negligible effect on the overall system performance. For the flow rate of 50 L per minute and inlet heat transfer fluid temperature of 303 K, the overall, exergy and thermal efficiency using a uniform helical wire coil flow insert are found to be 2.07 %, 2.1 %, and 2.2 %, respectively. © 2024 The Authors
29.	Sanchez-Roncero, Alejandro, et al. (author) The Sustainable Development Goals and Aerospace Engineering : A critical note through Artificial Intelligence 2023 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 17 Journal article (peer-reviewed)abstract The 2030 Agenda of the United Nations (UN) revolves around the Sustainable Development Goals (SDGs). A critical step towards that objective is identifying whether scientific production aligns with the SDGs' achievement. To assess this, funders and research managers need to manually estimate the impact of their funding agenda on the SDGs, focusing on accuracy, scalability, and objectiveness. With this objective in mind, in this work, we develop ASDG, an easy-to-use Artificial-Intelligence-based model for automatically identifying the potential impact of scientific papers on the UN SDGs. As a demonstrator of ASDG, we analyze the alignment of recent aerospace publications with the SDGs. The Aerospace data set analyzed in this paper consists of approximately 820,000 papers published in English from 2011 to 2020 and indexed in the Scopus database. The most-contributed SDGs are 7 (on clean energy), 9 (on industry), 11 (on sustainable cities), and 13 (on climate action). The establishment of the SDGs by the UN in the middle of the 2010 decade did not significantly affect the data. However, we find clear discrepancies among countries, likely indicative of different priorities. Also, different trends can be seen in the most and least cited papers, with apparent differences in some SDGs. Finally, the number of abstracts the code cannot identify decreases with time, possibly showing the scientific community's awareness of SDG.
30.	Schenk, F., et al. (author) Enhanced large-scale atmospheric flow interaction with ice sheets at high model resolution 2019 In: Results in Engineering. - : Elsevier. - 2590-1230. ; 3 Journal article (peer-reviewed)abstract The development in supercomputing power allows running full-complexity Earth System Models (ESM) at increasingly higher spatial resolutions on a global scale. We show here a recent example where increased model resolution leads to a fundamentally different large-scale fluid dynamical adjustment of the mean wind pattern to the presence of an ice sheet over Europe compared to a coarse resolution simulation. While the higher resolution allows for a more realistic representation of atmospheric flow interaction with complex topographic features, the interpretation and prediction of the model results with a stronger bottom-up mechanical and thermal forcing on the atmosphere becomes increasingly difficult to be studied within a fully coupled model. We emphasize that interdisciplinary approaches should be pursued where the experience from engineering approaches of studying flow around objects and the influence of boundary-layer processes can help to disentangle the complexity within ESM. Ultimately, such engineering approaches will add a more fundamental theoretical understanding and prediction of expected flow interactions and will help to design full-complexity atmospheric model experiments accordingly.
31.	Sekulic, Dragan, 1976, et al. (author) Safe speeds for a heavy articulated vehicle when passing a floating bridge tower under crosswind 2024 In: Results in Engineering. - 2590-1230. ; 23 Journal article (peer-reviewed)abstract This paper recommends safe speeds for a heavy articulated vehicle when passing by Bjørnafjorden floating bridge tower under two constant crosswind speeds (65 km/h and 100 km/h). The analysis is based on the tractor-semitrailer (TS) model with fifth-wheel (FW) coupling in roll and free in yaw. Comparison of safe speeds assessments has been made with two TS models differ in FW coupling. Aerodynamic forces and moments for TS models as function of their position relative to the bridge tower and time were computed using Computational Fluid Dynamics (CFD) simulations. For TS model coupled in roll and free in yaw, no rollover risk is noticeable for both crosswind excitations. For TS model free in roll and in yaw, roll-over risk is noticeable at lower vehicle velocities (at 36 km/h and 54 km/h). TS with rigid connection in FW stays in the traffic lane for every considered vehicle velocity. TS model which is roll and yaw moment free in the FW overestimates rollover risk assessment at lower vehicle velocities. TS model with rigid connection in the FW underestimates traffic lane departure assessment at higher vehicle velocity. Appropriate mathematical modelling of a heavy articulated vehicle that considers tractor and semitrailer units as two separate bodies coupled in roll and free in yaw is of importance for accurately assessing safe speeds when a vehicle passing by the bridge tower.
32.	Sirmacek, Beril, et al. (author) Remote sensing and AI for building climate adaptation applications 2022 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 15 Journal article (peer-reviewed)abstract Urban areas are not only one of the biggest contributors to climate change, but also they are one of the most vulnerable areas with high populations who would together experience the negative impacts. In this paper, we address some of the opportunities brought by satellite remote sensing imaging and artificial intelligence (AI) in order to measure climate adaptation of cities automatically. We propose a framework combining AI and simu-lation which may be useful for extracting indicators from remote-sensing images and may help with predictive estimation of future states of these climate-adaptation-related indicators. When such models become more robust and used in real-life applications, they may help decision makers and early responders to choose the best actions to sustain the well-being of society, natural resources and biodiversity. We underline that this is an open field and an on-going area of research for many scientists, therefore we offer an in-depth discussion on the challenges and limitations of data-driven methods and the predictive estimation models in general.
33.	Thakur, Hemant, et al. (author) Biogas production from anaerobic co-digestion of sewage sludge and food waste in continuously stirred tank reactor 2022 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 16 Journal article (peer-reviewed)abstract The purpose of current investigation was to explore the scope of integrating an anaerobic digester in a decentralized municipal wastewater treatment plant for in-situ treatment of household waste. The present work intends to identify the potential of sewage sludge and food waste for biogas generation. The study was conducted in lab scale continuous stirred tank reactor having a working volume of 6.5 L at mesophilic temperature. The paper mill sludge was used as inoculum and was stabilised using food waste substrate for initial 50 days in batch mode. Co-digestion of food waste (FW) and bio-flocculated sewage sludge (BFS) was performed using continuous feeding for maintaining OLR of 2.5 gVSL- 1D- 1at HRT of 4 days for 120 days. 2% FW and 98% BFS (by volume) was feeded in the reactor throughout the experimental duration. The highest VFA accumulation of 1902 mg L-1 were observed and maximum bio-methane yield was found to be 127.05 mLCH4 g- 1 VSadded. The pH with current feeding ratio was found stable during the reactor operation without adding external alkalinity source.
34.	Thakur, H., et al. (author) Investigation of continuous stirred tank reactors for improving the mixing in anaerobic digestion : A numerical study 2023 In: Results in Engineering (RINENG). - : Elsevier. - 2590-1230. ; 19 Journal article (peer-reviewed)abstract In this paper, mechanical impeller mixing has been analyzed through CFD which has proven to be a useful method for simulating mixing before manufacturing the digester. In this work, simulations were done for five different digester designs for TS level of 12.1%. While the fifth digester was cylindrical, the other four were cubical in design with varying impeller diameters and the number of impellers. The power law model was used to resemble the sewage sludge as a non-Newtonian fluid. The modified versions of dead volume and uniformity index were used along with velocity gradient and mixing energy level to quantify the quality of mixing. An analysis of the temperature distributions during mixing and heating was done using a thermal study. The operating speed of 250 rpm was finalized after testing at continuously increasing speeds from 50 to 600 rpm for a flat blade type impeller. As per the thermal model, a 250-W heater raised the temperature by around 15 °C in just 10 min. It was found that cylindrical vessels worked better than cubical digesters and larger impellers also helped in improving the mixing. The cylindrical digester which achieved about 67% homogeneity at a mixing energy level of around 0.95 W/m3, was the optimum design among the investigated digesters. © 2023 The Authors
35.	Varriale, Francesco, et al. (author) On the impact of pad material ingredients on particulate wear emissions from disc brakes 2023 In: Results in Engineering. - 2590-1230. ; 19 Journal article (peer-reviewed)abstract Besides friction and wear, airborne particle emission has become a central parameter when evaluating disc brake performance due to its potential adverse health effects as component of ambient air pollution. The pad friction material of brake system is composed of a mixture of ingredients grouped into four material categories: abrasives, reinforcing fibres, lubricants, and fillers. Some other ingredients which do not typically belong to aforementioned categories can be attributed to “fixed material”, such as aramid fibre, which is usually added into brake pad to harmonize the overall tribological properties. There is a gap of knowledge about how one ingredient from one category contributes to the emissions of particle number (PN) and mass (PM2.5, PM10). To investigate this, one ingredient from each category was chosen and produced as pins. As a reference, pins made of a commercial European brake friction material were also produced. The pins were tested using a pin-on-disc tribometer designed for airborne emission studies. Coefficient of friction, particle mass and number concentrations were measured during the tests. The results indicate that the abrasive and metal fibre have PN, PM2.5, and PM10 emission factors that are orders of magnitude higher than the lubricant and aramid fibre.
36.	Vinuesa, Ricardo, et al. (author) A socio-technical framework for digital contact tracing 2020 In: Results in Engineering (RINENG). - : Elsevier B.V.. - 2590-1230. ; 8 Journal article (peer-reviewed)abstract In their efforts to tackle the COVID-19 crisis, decision makers are considering the development and use of smartphone applications for contact tracing. Even though these applications differ in technology and methods, there is an increasing concern about their implications for privacy and human rights. Here we propose a framework to evaluate their suitability in terms of impact on the users, employed technology and governance methods. We illustrate its usage with three applications, and with the European Data Protection Board (EDPB) guidelines, highlighting their limitations.
37.	Vinuesa, Ricardo (author) High-fidelity simulations in complex geometries : Towards better flow understanding and development of turbulence models 2021 In: Results in Engineering (RINENG). - : Elsevier BV. - 2590-1230. ; 11 Journal article (peer-reviewed)abstract The present review shows a summary of current trends in high-fidelity simulations of turbulent flows in moderately complex geometries. These trends are put in the historical context of numerical simulations, starting with early weather predictions and continuing with seminal direct-numerical-simulation work. Here we discuss high-fidelity simulations conducted in a number of complex geometries, including ducts, pipes, wings and obstacles, and describe the potential of the spectral-element method (SEM) to carry out such simulations. Finally, we provide a number of future directions where novel data-driven methods can exploit the great wealth of highquality turbulence data in the literature.
38.	Wahlström, Jens, PhD/Docent, 1979- (author) A pin-on-disc tribometer study of friction at low contact pressures and sliding speeds for a disc brake material combination 2019 In: Results in Engineering. - : Elsevier. - 2590-1230. ; 4 Journal article (peer-reviewed)abstract Disc brake creep groan is a stick-slip phenomenon which results in a low frequency noise in road vehicles that could occur at low vehicle speeds and brake torques. Simulation approaches are used predict the stick-slip phenomena for disc brakes. These approaches depend on the friction model used. Tribometers can be used to map how the local coefficient of friction (CoF) depends on the contact pressure (p) and sliding speed (v). A CoF pv-map can be used as friction model in simulation approaches. There is a lack of CoF maps at low contact pressures and sliding speeds are reported in the literature. The aim of the presented study is to map the CoF for a disc brake material combination at low contact pressures (0.03–0.28 MPa) and sliding speeds (0–3.8 mm/s). The result shows that the friction decreases with increased contact pressure and sliding speed for the specific material combination tested and the test conditions used. More studies are needed to further investigate the validity of the results.

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