172 research outputs found
Modified Broms’ method for formation of working platform on very soft soil
No full textConstruction over soft soil is a challenge as the ground can be too soft to work on it. To overcome this, a working platform has to be formed before any soil improvement work can be carried out. One of such methods was proposed by Broms (1987) which uses geotextile and sand berms. In this paper, a modified Broms' method is proposed to use geotextile tubes to confine the sand berms. A new analytical solution is also proposed to calculate the tensile strain and the profile of geotextile under the sand berms/tubes. Design charts for different design conditions are also developed. Parametric studies were conducted to identify the key parameters affecting the design. Finite element analyses (FEA) and a field trial were also carried out to verify the modified Broms' method and the proposed solution. The monitoring data agree reasonably well with the results obtained from proposed solution and FEA. A design procedure for modified Broms' method and Broms’ method is proposed using the analytical solution.Nanyang Technological UniversityThe field trial was carried out as a research project jointly with JTC Corporation, Singapore. The financial support from the JTC Corporation through the NTU-JTC Industrial Infrastructural Innovation Centre (I3C) is gratefully acknowledged. The first author is also grateful to the scholarship provided by NTU for his PhD
Airway management in emergency anaesthesia
No full textBackgroundAirway management in critically ill patients, particularly rapid sequence induction and intubation (RSI) for emergency anaesthesia, remains a high-stakes and time-critical procedure associated with significant morbidity and mortality. Maximizing first-pass success (FPS) is a critical quality target, as multiple intubation attempts correlate with increased adverse events. Current global guidelines stress the need for a systematic approach to technical execution, patient physiology, operational logistics, and human factors to refine safe practices. The Scandinavian Helicopter Emergency Medical Service (HEMS) system, which is staffed by highly experienced anaesthesiologists, operates under challenging constraints, necessitating research that validates adaptable techniques and effective team dynamics. Historically, prehospital guidelines have advocated for 360-degree access outside the vehicle, potentially increasing critical on-scene time. Furthermore, contemporary practice has explored the use of alternative adjuncts for emergency anaesthesia, such as high-flow nasal oxygen (HFNO) for preoxygenation and prolonging the safe apnoea time, that can further mitigate these risky procedures. However, robust, multicentre evidence supporting operational changes, such as in-cabin intubation or quantifying the influence of the airway assistant, has been sparse. This thesis sought to contribute empirical evidence across these domains. The first phase of this doctoral project focused on evaluating the safety profile of HFNO as an alternative preoxygenation strategy within the emergency surgical population. The next trial addressed logistical constraints in prehospital care, specifically testing whether intubating within the confined space of a vehicle could match the success rates of traditional exterior procedures. Finally, we utilized the same dataset to explore human factors, specifically analysing whether the professional designation of the assisting provider correlated with procedural outcomes.MethodsThis thesis comprises three clinical studies, Study I ("PRIOR2"), a prospective, randomized controlled, international multicentre trial conducted across six centres in Sweden and Switzerland (n=349). Patients who underwent RSI for emergency surgery were randomized 1:1 to receive preoxygenation with HFNO or a tight-fitting facemask. The primary outcome was the incidence of oxygen saturation (SpO2) less than 93% from the start of preoxygenation until one minute after tracheal intubation. Study II ("PHASTER"), a prospective, observational, international multicentre study involving 12 HEMS bases across Scandinavia (n=422 drug-assisted tracheal intubations). This study was designed as a noninferiority trial to compare FPS and complication rates when intubation was performed in-cabin (in a helicopter or ambulance) versus outside. The primary outcome was the FPS rate. Noninferiority was defined by a margin (Δ) of -4.5%. Propensity score matching was used to adjust for confounding factors related to the observational nature of the location choice. Study III (PHASTER Subgroup Analysis), a retrospective subgroup analysis of Study II data (n=422) investigating the influence of the airway assistant's professional background, anaesthetist (anaesthesiologist or nurse anaesthetist) vs. nonanaesthetist (e.g., other physician, other nurse or paramedic), on FPS and complication rates. Binary logistic regression was used to calculate adjusted odds ratios (aORs) for the outcomes, adjusting for covariates such as initial patient condition, VL use, and operator experience.ResultsStudy I: No difference was detected in the primary outcome, desaturation within one minute of intubation. Five patients (2.9%) in the HFNO group desaturated below 93%, whereas six patients (3.4%) in the facemask group desaturated (p=0.77). No difference was detected in the incidence of gastric regurgitation or desaturation between office hours and on-call hours. There was a greater incidence of desaturation in the Switzerland cohort (7%) than in the Sweden cohort overall (1.6%) (p = 0.009).Study II: The FPS rate was 89.2% for in-cabin procedures and 86.3% for outside procedures. The confidence interval for the difference did not include the noninferiority margin (Δ= -4.5) and therefore successfully met the predefined criteria for noninferiority. Intubations performed in the helicopter cabin resulted in a significantly shorter mean on-scene time (27 minutes vs. 32 minutes, p=0.004).Study III: FPS was nearly identical between the anaesthetist-assisted (88.1%) and nonanaesthetist-assisted (87.8%) groups. The assistant profession was not independently associated with FPS (aOR 1.05, 95% CI 0.54-2.12) or overall complication rates (aOR 1.79, 95% CI 0.66-5.39).ConclusionsThis thesis validates essential strategies for increasing the standard of emergency airway management. The results of Study I support technical efficacy and flexibility. HFNO is deemed a functionally equivalent and as good alternative to facemask preoxygenation during RSI, offering crucial technical flexibility, particularly for physiologically compromised patients, by supporting the strategy of continuous apneic oxygenation. Study II highlights logistical efficiency since the in-cabin intubation procedure is noninferior to outside intubation in terms of FPS and safety while achieving a significantly shorter on-scene time. This provides evidence-based justification for adapting HEMS SOPs to maximize logistical efficiency without compromising core safety metrics. Study III adds perspectives on team resilience. In highly experienced, protocol-driven emergency medical systems, team performance and system governance are dominant predictors of success, as the professional background of the airway assistant does not independently influence outcomes. Taken together, these results support a flexible, patient- and context-tailored approach to RSI, prioritizing FPS through meticulous techniques, optimized logistics, and sustained investment in multidisciplinary team processes and systemic governance.List of scientific papersI. Preoxygenation using high-flow nasal oxygen vs. tight facemask during rapid sequence induction. A. Sjöblom, J. Broms, M. Hedberg, Å. Lodenius, A. Furubacke, R. Henningsson, A. Wiklund, S. Nabecker, L. Theiler, M. Jonsson Fagerlund. Anaesthesia, 2021; 76: 1159-62. https://doi.org/10.1111/anae.15426II. Prehospital tracheal intubations by anaesthetist-staffed critical care teams: a prospective observational multicentre study. J. Broms, C. Linhardt, E. Fevang, F. Helliksson, G. Skallsjö, H. Haugland, J. Knudsen, M. Bekkevold, M. Tvede, P. Brandenstein, T. Hansen, A. Krüger, L. Rognås, HM. Lossius, M. Gellerfors. British Journal of Anaesthesia, 2023 1;131(6):1102-11. https://doi.org/10.1016/j.bja.2023.09.013III. The impact of airway assistants on prehospital endotracheal intubations - a subgroup analysis of data from anaesthesiologist-staffed helicopter critical care teams. J. Broms, M. Günther, C. Svensén, A. Krüger, L. Rognås, M. Gellerfors. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 2025, Nov 25. https://doi.org/10.1186/s13049-025-01515-y</p
Laterally Loaded Piles, Models and Measurements
No full textA thesis presented on the comparison between different geotechnical models for single piles, which are loaded laterally at the top, on the basis of field measurements. The considered models are Blum, Brinch Hansen, Broms, the Characteristic Load Method, the Nondimensional Method, the Single Pile Module of MSheet, p-y Analysis by MPile and Finite Element Analysis by Plaxis.Geotechnical EngineeringGeo-EngineeringCivil Engineering and Geoscience
Dissertatio historica, de praestantia historiae sacrae prae profana: cujus partem priorem, consensu amplissimi senatus philosophici in Regia Academia Aboënsi, praeside mag. Johanne Bilmark, hist. & phil. pract. prof. reg. & orgin. Atque facultatis philosoph. h. t. decano, publicae bonorum censurae subjicit Andreas Öberg, Nericia-Svecus. In aud. Maj. die IX. Dec. anni MDCCLXVII. H. p. m. s
No full textInvocatio: Deo duce.Dedicatio: Renata Charlotta von Morian, f. Nieroth [ruots. pr.], Johan Broms [ruots. pr.].Arkit: 2 arkintunnuksetonta lehteä, A-B4 C2.Painovuosi nimekkeestä
Toward symmetric organic aqueous flow batteries: triarylamine‐based bipolar molecules and their characterization via an extended Koutecký‐Levich analysis
No full textSymmetric organic flow batteries (SOFBs) can potentially address membrane crossover problems by employing bipolar redox-active organic molecules (BROMs). Herein, a triarylamine (TAA) skeleton was chosen as a posolyte moiety for a new class of bipolar molecules for pH-neutral aqueous FBs. Pyridinium and viologen derivatives were tethered to the posolyte moiety, and the new compounds were characterized. Cyclic voltammetry revealed that only viologen with a highly hydrophilic substituent, connected to the TAA moiety via a Zincke reaction, could be reversibly reduced. Varying the supporting electrolyte concentration on the selected derivative revealed water solubility as a challenge for further development. The selected derivative, MeO-TPA-Vi-DMAE, was subjected to hydrodynamic voltammetry, and a modified Koutecký-Levich analysis was developed to investigate the observed potential-dependent currents at the hydrodynamically dominated region, which are often seen with redox-active organic molecules. This model discarded a purely Ohmic effect, showing a useful Levich slope at a certain overpotential before the onset of a secondary reaction. TAA-based BROMs hold promise for pH-neutral aqueous SOFBs, and the results will guide the design of new derivatives. The three-term Koutecký-Levich relation here introduced will be useful not only to develop BROM-based flow batteries but will most likely appeal to a much broader audience
Effects of temperature and body size on the clearance rate of Oikopleura dioica
No full textThe effects of temperature and body size on the clearance rate of the appendicularian Oikopleura dioica were investigated. The clearance rate increased with the trunk length of the animals according to a power function with exponent 3.2 +/- 0.17 (range 2.9-3.8). The intercepts of the three regressions were significantly different with the highest rates at 20degreesC, corresponding to a Q(10), value of 1.78 (10-20degreesC)
Un'estensione della Teoria di Broms nel calcolo dei pali sollecitati da forze orizzontali
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