415 research outputs found
David E. Aune, Prophecy in Early Christianity and the Ancient Mediterranean World, 1983
No full textIngelaere Jean-Claude. David E. Aune, Prophecy in Early Christianity and the Ancient Mediterranean World, 1983. In: Revue d'histoire et de philosophie religieuses, 65e année n°2, Avril-juin 1985. pp. 208-209
Data-driven approach to account for fluid-structure interaction effects on blast loaded steel plates
No full textBulk Metallic Glasses: Deformation and Design
No full textBulk metallic glasses are a group of alloys with amorphous atomic structure. When these alloys cool sufficiently fast, the atoms will “freeze” in the chaotic structure of the melt, rather than form crystals like most metals. The resulting materials are often very strong, hard and corrosion resistant, but brittle compared to their crystalline counterparts.
Two key limitations to the applicability of bulk metallic glasses are the focus of this thesis. Firstly, the typically very limited plasticity in tension is studied by tensile testing metallic glass samples across a range of temperatures and strain rates. Secondly, a design tool for reducing the normally high cost of discovery of new alloys is tested.
Zr70Ni16Cu6Al8 bulk metallic glass samples were mechanically tested in tension at nominal strain rates and temperatures of 10-4, 10-3, 10-2 and 10-1 s-1 and 77, 150 and 295 K, respectively. A strengthening is observed with decreased temperature, with yield strength increasing by an average of 16 % from 1503 MPa at 295 K to 1746 MPa at 77 K. Plastic deformability is found highest at 150 K, intermediate at 77 K, and very low at 295 K. At room temperature only a single sample showed any plastic deformation, which occurred due to the intersection and mutual stabilization of several shear bands. At the two lower temperatures, large plastic deformation was accommodated by the stable sliding of a single shear band. Between 150 and 295 K a reversal of strain rate sensitivity is observed, with high strain rate favoring high strength and low plasticity at low temperature and vice versa at room temperature.
In-situ probing of heat generation during the stable sliding of a shear band is achieved by studying localized boiling along the shear band in a sample submerged in liquid nitrogen during testing. By measuring size and frequency of the bubbles, heat release is correlated to plastic deformation, showing that heating occurs even during stable flow at cryogenic temperature, but only becomes noticeable well after onset of deformation. Heat release is therefore considered to be a secondary effect of the shear band deformation.
In the final part of the thesis, a tool for design of new glassy alloys is tested. By combining thermodynamic modelling in the Thermo-Calc software with a topological mismatch factor based on constituent atomic size and compositional ratios, an area in the Fe-Nb-B phase diagram is pinpointed as favorable for glass formation. Both new experimental production and literature data fit well with the predictions of the model, making it worthy of further testing in other systems
Welded aluminium connections - Behaviour and numerical modelling for large-scale simulations
No full textThis PhD thesis explores the behaviour and modelling of welded aluminium connections. It is divided into four parts: Parts 1 and 2 have been published in peer-reviewed journals, while Part 3 has been submitted for potential publication. Part 4 is a technical report that documents supplementary investigations related to this PhD project, not covered in Parts 1-3. Each part is an individual study and can be read independently. The thesis begins with a synopsis that introduces the work, followed by a presentation of its objectives, scope, and research methodology. The synopsis concludes with summaries of each part, key conclusions, and suggestions for further research.
Part 1 presents a combined experimental and numerical study on the tensile ductility of aluminium alloys subjected to heat treatments representative of welding. The experimental part includes specimen preparation and uniaxial tensile testing. A Gleeble machine generates heat treatments with high peak temperatures and heating rates that mimic those from a welding process. Following this, uniaxial tension tests are conducted at low and high strain rates. The results highlight the effects of these heat treatments on strength, strain-rate sensitivity, and fracture behaviour. The numerical part of this study examines two widely used damage models: the Cockcroft-Latham fracture criterion and the Gurson-Tvergaard model. Material models are calibrated and a parameter study is conducted based on the tension tests. A case study is also performed to emphasise the significance of the damage parameters within an idealised heat-affected zone and under plane-strain tension. The main objective is to improve the modelling of ductile fracture for aluminium alloys exposed to welding-like heat treatments.
Part 2 presents a study on the behaviour and modelling of simple cross-welded connections. This study focuses on large-scale analyses, where the weak zones are represented with a few shell elements. A shell-element modelling framework suitable for large-scale analyses is thus proposed, which accounts for geometrical instability, thinning, and ductile fracture. Calibration and validation of the proposed modelling framework are performed using cross-weld tension tests. The test campaign includes tensile testing of two Al-Mg-Si alloys (AA6082 and AA6060) and two widely used welding techniques (MIG and FSW). The main objective is accurately capturing the overall weld and heat-affected zone (HAZ) behaviour under cross-weld tensile loading with shell-element simulations. Two approaches are investigated where the size of the HAZ is either fully modelled or lumped into one row of elements. The shell-element simulations of the cross-weld tension tests, with several element sizes larger than the plate thickness, show reasonable agreement with the experimental results.
Part 3 investigates the testing and modelling of welded aluminium joints at the component level. A novel test campaign examines the behaviour of a welded T-joint under quasi-static and impact loading. The deformation is confined to the heat-affected zones (HAZ), which corresponded well with the low hardness values of the HAZ compared to the base and weld materials. Higher force levels were observed in the impact tests compared to the quasi-static tests, indicating that the T-joint under impact loading experienced inertia and strain-rate effects. This study’s numerical part considers the HAZ modelling using shell elements. A virtual calibration procedure is proposed to establish model parameters applicable in large-scale analyses based on the output from a welding simulation and a microstructure-based model. The virtual calibration procedure is benchmarked against the welded T-joint and a cross-weld tensile case, where the base and HAZ materials’ hardness, yield stress, and work hardening are captured reasonably well. To this end, shell-element simulations of the T-joint tests are conducted, and the results resemble those of the experiments to a great extent.
Part 4 of this PhD thesis is a technical report documenting experimental studies carried out as part of this project, which were not included in Parts 1-3. A substantial part of the T-joint test campaign was omitted from Part 3 to satisfy the journal’s page limit. Further, a weld start and stop activity is documented, where cross-weld tensile testing was conducted with specimens having either a weld start or stop. Single-lap joints have also been tested as a part of this PhD project, where the weld was subjected to unfavourable loading conditions. A common observation for all tests reported herein is that fracture initiation occurred within the weld, in contrast to Parts 1-3, where it occurred within the HAZ
Electrical Engineering Alumnus Helps Entrepreneurs Succeed
No full textDavid Aune serves on engineering school\u27s advisory boar
Review of Norwegian support to FIFAMANOR By
No full textNorwegian University of Life Sciences (UMB). Noragric’s activities include research, education and assignments, focusing particularly, but not exclusively, on developing countries and countries with economies in transition. Besides Noragric’s role as the international gateway for UMB, Noragric also acts on behalf of the Norwegian College of Veterinary Medicine (NVH) and of Norwegian Agricultural Research International (NARI), which form alliances with UMB. Noragric Reports present findings from various studies and assignments, including programme appraisals and evaluations. This Noragric Report was commissioned by the Norwegian Agency for Development Cooperation (NORAD). Extracts from this publication may only be reproduced after prior consultation with the consultant team leader (Jens Aune). The findings, interpretations and conclusions expressed in this publication are entirely those of the author(s) and cannot be attributed directly to the Department of International Environmen
The sense of a beginning : Bakhtinian dialogic criticism on 'the gospel' in Mark.
No full textContemporary literary approaches have caused paradigm shifts in Biblical Studies in the last two decades as it appears in a great deal of Markan studies using narrative, reader-response, deconstructive, feminist, and new historicist approaches. However, literary studies on the Gospel of Mark have not taken into account theoretical questions underlying those approaches. As a result biblical critics are driven by new trends without ever having a chance to examine the critical baggage of the approaches. Consequently, there is a gap of communication between the old and the new one. Therefore this thesis is an attempt to meet the need of enhancing the quality of critical endeavour in biblical studies. In the light of most recent competing critical theories of literature, the first contribution of this thesis is the methodological finding that Bakhtinian dialogic criticism contains the most profound philosophical and practical foundations for solving some crucial theoretical problems in contemporary literary theories. It is a critique to a Saussurian linguistic system of language which becomes the very foundation of modern and postmodern literary criticism. Bakhtinian literary theory shifts the foundation of literary criticism on linguistic signs into the creative activity of the socio-cultural production of human communication. The shift into socio-cultural reality of language communication makes the notion of 'genre' very important to unlock the problem of text and context in literary studies. Since the Gospel of Mark has fascinated most literary critics in Biblical Studies, the problem of 'genre' of this gospel is chosen as the focus of this study. Secondly, as no agreement is reached as to what 'genre' the Gospel of Mark belongs, this thesis makes its contribution to the discussion by locating the problem of 'genre' of Mark in the context of genre theories and argues that the Bakhtinian suggestion to find genre in the socio-cultural sphere by analysing artistic intercourse between narrative agents in Mark has freed the competing analysis from the unresolved problem between the kerygmatic (content oriented) approach and the analogical (form oriented) approach. To achieve finding 'genre' in the socio-cultural sphere, this thesis focuses on Bakhtinian analysis of the process of artistic intercourse between narrative agents. The narrative communicative interrelationships between narrative agents is constructed in this thesis as a 'stereophonic' Bakhtinian model of dialogic communication. This model is an original contribution of this thesis for revising the traditional two dimensional model of narrative communication. Based on this dialogical model of communication, a special role is given to the Bakhtinian 'author-creator' in the realization process of genre through the interaction of polyphonic voices. Through the interaction of voices of the author-artist and the hero we are led to discover a relatively stable type of portraying and controlling reality in Mark, known as the genre of Roman 'satire'. The closest literary affinity is Satyrica by Petronius. This narrative strategy of 'satire' in Mark has its root in the prophetic discourse of the Old Testament which is saturating the speech of the narrator, John the Immerser, the centurion, the people, and even Jesus. Finally, the whole search for Markan 'genre' culminates in the analysis of the realization of genre through the analysis of Bakhtinian chronotope. The reality of the genre of Mark is its social reality that is in its role as dpxrj/ 'beginning'. As the Gospel of Mark proclaims itself as 'a beginning', it defines its claim of socio-cultural 'authority' in early Christianity. It is this 'sense of beginning' which enables the narrating and the narrated world of Mark to interact dialogically
Behaving as a convert : moral teaching in Ephesians against its traditional and social backgrounds.
No full textThe study examines Eph 4:1-5:20. Consisting of five chapters, it probes the following five passages: 4:1-16; 4:17-24; 4:25-5:2; 5:3-14; and 5:15-20. Each chapter investigates the relevant verses exegetically, focussing on behavioural aspects. This overview is then compared with issues raised in chapters 1-3, with similar notions of morality from antecedent Pauline writings and with selected Jewish and Graeco Roman writings. The final section of each chapter builds and then applies a social science or social history model. Though exhibiting differences from Paul's undisputed writings, the basic moral view of these verses is Pauline. Various Jewish writings (LXX, Greek versions of OT Pseudepigrapha and relevant passages from Josephus, Philo and Qumran) are brought to bear on these verses. Certain Graeco-Roman writings, (Plato's Laws, Aristotle's Nicornachean Ethics and discourses from Dio Chrysostom and Epictetus) are also examined. Though a remarkable number of affinities exist between Ephesians and these other writings, no evidence of direct influence is detected. Rather, Ephesians appears to be a product of its age, expressing similar ideas because it shares elements of a common world view. Ephesians differs from most of the non-Pauline writings examined by linking morality with religious devotion. Social network and exchange theories (chapter 1), New Religious Movements theories (chapters 2 and 3), principles from honour and shame cultures (chapter 4) and a social model from symposia (chapter 5) were applied to relevant passages. Though historical circumstances behind the letter are unknown, Ephesians' moral teaching portrays human situations. The NRM theory applied in chapters 2 and 3 proved to be particularly helpful in explaining how Ephesians' rejection of gentile immorality (4:17-19) does not contradict its acceptance of gentile social structures
Deep learning-based analysis to identify fluid-structure interaction effects during the response of blast-loaded plates
No full textBlast events within urban areas in recent decades necessitate that protective design is no longer reserved for military installations. Modern civil infrastructure composed of light-weight, flexible materials has introduced the consideration of fluid-structure interaction (FSI) effects in blast-resistant design. While the action of blast loading on massive, rigid structures in military fortifications is well established, assessment of FSI effects is, at present, only possible through computationally expensive coupled simulations. In this study, a data-driven approach is proposed to assist in the identification of the blast-loading scenarios for which FSI effects play a significant role. A series of feed-forward deep neural networks (DNNs) were designed to learn weighted associations between characteristics of uncoupled simulations and a correction factor determined by the out-of-plane displacement arising from FSI effects in corresponding coupled simulations. The DNNs were trained, validated and tested on simulation results of various blast-loading conditions and material parameters for metallic target plates. DNNs exposed to mass-per-unit-area, identified as an influential factor in quantifying FSI effects, generalised well across a range of unseen data. The explainability approach was used to highlight the driving parameters of FSI effect predictions which further evidenced the findings. The ability to provide quick assessments of FSI influence may serve to identify opportunities to exploit FSI effects for improved structural integrity of light-weight protective structures where the use of uncoupled numerical models is currently limited
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