66 research outputs found
Introduction and Letter to Firas and Ali
No full textIn this deeply personal and politically charged epistolary essay, Joanna Zabielska reflects on the intersecting forms of erasure occurring within European cultural institutions and at the continent’s militarized borders. Framed as a letter to two men—Firas and Ali—whom the author met during the humanitarian crisis at the Polish-Belarusian border, the piece recounts their experiences of pushbacks, violence, detention, and survival, contextualizing their stories within a broader critique of European migration regimes. Zabielska juxtaposes this with her account of institutional censorship in Austria, where the names of the two men were removed from her VR installation Über das Neue at Belvedere 21. Across these narrative layers, the essay examines how identities, testimonies, and lives are rendered invisible by political pressure, racism, and the rhetoric of “neutrality.” Drawing on Wisława Szymborska’s poem Conversation with a Stone, Zabielska highlights art’s ethical imperative to bear witness and resist silence. The text functions simultaneously as testimony, memorial, and act of solidarity with displaced people whose stories remain unheard
Stonefish Synanceia verrucosa Bloch & Schneider, 1801 (Actinopterygii: Synanceiidae): the first record in the Syrian coast and the fourth in the Mediterranean
No full textFish species introduction into the Mediterranean Sea is constantly increasing, and this is what worries biologists especially after the arrival of poisonous species. In this paper, Synanceia verrucosa is recorded for the first time in the Syrian marine waters, filling the gap of its distributions between north and south of the eastern Mediterranean
First record of Red cornetfish, Fistularia petimba Lacepède, 1803 (Actinopterygii: Fistulariidae) from the Syrian coast
No full textFistulariidae species (Cornetfishes) exist in tropical and subtropical waters having four species; two of them are found in the Mediterranean Sea. This study records Fistularia petimba from the Syrian marine waters for the first time, filling the gap in its distribution along the eastern Mediterranean
Argument properties of certain classes of meromorphic functions related to Cho-Kwon-Srivastava operator
No full textThe role of non-ionic surfactant-extracellular polymeric substances in removal of Listeria monocytogenes biofilm formed on different contact surfaces
No full textThe occurrence of biofilm in food processing environments can lead to spoilage and transmission of diseases, this aided in the development of this study. Listeria monocytogenes can cause serious and possibly fatal illnesses in humans and animals after ingestion the contaminated food. Spinach can be contaminated by L. monocytogenes during harvest. The effectiveness of six nonionic surfactants (Pluronic F68, Pluronic F127, Tween 20, Tween 40, Tween 80, and Brij 58) were evaluated in disrupting L. monocytogenes biofilms on the surface of spinach leaves. Wells were washed with surfactants after incubation and then mixed on a platform shaker for 1, 5, 15, and 30 min. Then, the wells were rinsed with distilled water to remove dead cells, and fixation was conducted at 30 min at 60 °C. Our findings showed that Brij 58 most effectively removed the L. monocytogenes biofilm on spinach, followed by Pluronic F127, Tween 80, Tween 40, Tween 20, and Pluronic F68.In the second experiment, the effectiveness of different types of nonionic surfactants such as Pluronic F68, Pluronic F127, Tween 20, Tween 40, Tween 80 and Brij 58 against the Listeria monocytogenes biofilm cells formed on food contact surfaces made of Low-Density Polyethylene (LDPE), Polypropylene (PP), Low-Density Polyethylene and Polypropylene (LDPE-PP), Low-Density Polyethylene and Ethylene Vinyl Acetate (LDPE-EVA), Stainless-Steel and Aluminum was determined.Acridine Orange staining (AOS) to quantify the amount of the L. monocytogenes biofilm cells that were destroyed by the nonionic surfactants after different time intervals of 1, 5, 15 and 30 min.Ph.D.Includes bibliographical referencesby Firas S. Albayat
Evolution of the welding residual stresses after cutting of a cruciform welded joint
No full textThe use of welding is widely adopted to assemble structural components in the construction industry for many years. To ensure safety of these welded components, many fatigue tests have been conducted on many different shapes and configurations of welded connections to precisely assess the fatiguelife. However, testing real-size structures and specimens is very limited due to it’s high cost and in-applicability. Thus, these full scale specimens are cut down into small scale specimens to allow applicability for testing. Different characteristics are exhibited between the full and the small scale specimens, as there are major difference in residual stresses induced by welding and cutting, which may give non conservative predictions for fatigue life.In this thesis, the objective is to forecast the evolution of the residual stress field originated by welding of a full scale and small scale specimens of a cruciform joint at the weld toe after breaking it down into smaller specimens using a cutting process by performing a numerical analysis using Abaqusfinite element analysis software. To achieve this goal, first, a thermo-mechanical welding simulation was performed to obtain a weldingresidual stress field on a 910 mm long cruciform joint, which is done in two main parts, starting with the thermal model in which a temperature field is analysed. The temperature field from the thermal modelis used as an input for the mechanical model in which the residual stress field is produced due to the temperature change and restriction of movement of material due to the shrinkage and expansion. Secondly, the 910 mm long full-scale cruciform joint was cut into five shorter specimens of 500, 210,120, 75, and 20 mm. The welding residual stress (WRS) levels at the weld toe for each specimen was recorded and showed large stress losses and relaxations as the specimen gets shorter in length. a major longitudinal stress loss of 97% and 77% loss of maximum principle stresses when cutting downthe 910 to a 20 mm long specimen, making it almost free of WRS, but only a 5-6% loss of longitudinal and Max. principal stresses when going from 910 to 500 mm. Thirdly, after generating multiple welded specimens with different lengths, a tension load of 186.2 is set in the x-direction of the attachment plate of the cruciform joint, and the stress level at the weld toe was analyzed due to the applied load and the WRS. A 40% increase of the stress occur due to theapplied load, but a very slight decrease in longitudinal stresses for the 910, 500 and 210 mm due to depicting a plate-like behaviour in contraction due to poisson’s effect. Finally, the same specimens were analysed under the 186.2 MPa load but without including the WRS. Different shapes of stress distributions were found, and differences in stresses when comparingthe models with and without WRS in the models. The difference in longitudinal z-direction reached up to 282 MPa, while only 77 MPa in the transverse direction. The maximum principle stresses insured the importance of including WRS when performing fatigue assessment as it showed the fatigue failure to occur in the weld root with a crack to happen at the middle part. The specimens that exclude WRS would start cracking at the edges of the weld root, but in the central part of the weld seam when including WRS. The model that included WRS showed similar fracture location at the weld root as the fractured specimen performed in tests at TNO’s laboratories.The next steps in this research is the modification of a modelling methods. The results can be improved and smoothed by modelling using the effective notch method were a radius is introduced at the weld toe and the root to eliminate the stress singularities. The welding simulation can be improvedto get better results by modelling the full cruciform joint without symmetry conditions, and include a weld order for all four welds with proper cooling time in between each weld.Civil Engineerin
Distributed surface-subsurface modelling approach for evaluating the impact of rain gardens on steep terrain
No full textAs the proportion of people living in urban low-lying areas increase dramatically over time, a large number of high and steep slopes have been modified in order to increase the available land cover. This expansion usually includes vegetation removal and construction of multiple engineered impervious surfaces that can result in increased severity of flooding events at the downstream valley regions. Sloped areas at the headwaters promote rapid downward movement of water towards the low-land regions, and infiltration capacity in mountain sides is relatively small due to the near-surface bedrock layer. Therefore, stormwater BMPs-LID can be considered as one of the effective approaches to reduce urban runoff quantity and quality from steep terrain areas.
Stormwater BMPs provide sustainable, cost effective, and ecologically-friendly approach to maintain natural pre-development hydrological functions and prevent the delivery of contaminants to the receiving waters. Structural BMPs, in particular rain gardens, were selected in this work. Moreover, an integrated surface-subsurface modeling tool, MIKE SHE, was utilized for simulating the performance of distributed rain garden cells in reducing urban runoff from steep residential catchments.
A series of hypothetical cases of rain gardens with distinctive characteristics, including different sizes and implementation densities, are simulated and results are reviewed and compared to the catchment response with no stormwater BMPs. Three typical storm events were selected for model simulation and evaluation of rain gardens on steep terrain, including a 60-min storm with a 25-year return period, a typical small storm exactly followed by the design storm, moderate storm after a long period of dry weather.
Analysis of variance (ANOVA) was conducted as part of statistical procedures in order to validate the effect of rain garden density and storm intensity on flow reduction. The statistical analysis helps to answer whether rain gardens on steep terrain systematically reduce runoff volumes or is this random noise due to random selection of hypothetical scenarios.
Simulation results suggest that implementing distributed rain gardens on steep terrain would reduce peak flow rates and runoff volumes of stormwater up to 60% and 50%, respectively. However, implementation density and rain garden allocation plays a major role in mitigating urban runoff quantities. The best-case scenario includes the construction of all potential rain gardens, as well as implementing rain gardens with areas of at least 8% of the impervious area within a catchment, to accomplish a peak reduction of around 65%.
The response of soil saturation to rain garden allocation within the steep catchment varied considerably in some implementation scenarios. Subsurface flows and artificial retaining walls significantly affected the performance of distributed rain gardens in reducing urban runoff. It is important to consider the impact of unsaturated zone flow when designing and planning rain gardens on sloped drainage basins for sufficient stormwater runoff control. Furthermore, rain gardens should be better allocated near upstream locations to result in better potential performance of rain gardens on steep terrain.
Statistical results indicated that rain garden density has a statistically significant effect on runoff reduction over steep terrain. However, implementing rain garden systems on hillslopes requires extra attention in the allocation of each cell in order to achieve adequate stormwater runoff control at a low implementation cost.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-05-01The student, Firas Rababaa, accepted the attached license on 2021-04-28 at 17:39.The student, Firas Rababaa, submitted this Thesis for approval on 2021-04-28 at 17:51.This Thesis was approved for publication on 2021-04-29 at 16:16.DSpace SAF Submission Ingestion Package generated from Vireo submission #16610 on 2021-09-16 at 17:06:46Made available in DSpace on 2021-09-17T02:34:51Z (GMT). No. of bitstreams: 2
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Previous issue date: 2021-04-29Embargo set by: Seth Robbins for item 118598
Lift date: 2023-09-17T02:34:57Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
Lachen und Weinen mit ungebetenen Gästen : Kulturelle Grenzüberschreitungen in Abbas Khiders Ohrfeige und Firas Alshaters Ich komm auf Deutschland zu
No full textThis study investigates literary representations of refugees in contemporary German literature. Specifically, it analyzes the autobiography Ich komm auf Deutschland zu (2016) written by a Syrian refugee, Firas Alshater, who arrived in Germany in 2013, and the auto-fictional novel Ohrfeige (2016) by the German-Iraqi author Abbas Khider, who sought asylum in Germany in 2000. Both authors write from a transcultural point of view which challenges the definition of German culture and its ostensible dividing lines. As refugees themselves, these transnational authors have created works that interact aesthetically with contemporary German and European asylum and migration law, while vividly portraying the affective aspects of flight, trauma, and resettlement for those who manage to reach Germany. Both authors make use of irony, satire, and parody, which turn their works into aesthetic interventions that bring together social and political debates surrounding the topic of refugees in modern Germany. Each oeuvre defies the representation of refugees as victims and cultural outsiders. The texts expose ways in which fear and anxiety construct images of refugees as threatening and by which they are relegated to the margins of society. Through Alshaters and Khiders work, readers may question the imagined boundaries of the nation-state and reconsider notions of belonging. The humor embedded in their writing teases out tensions, contradictions, and resonances across time and space. Particularly, the persistent desire to look to ethnicity as a presumed guarantor of Germany’s collective self is challenged. Alshater’s humoristic-ironic style as well as his application of allusion and imagery and Khider’s employment of parody expose national and cultural ambiguity. By humanizing the term “ethnicity,” which is primarily viewed as a public identity, the authors stress the inclusion of a personal component, pointing to a common human need for recognition. Readers of these two works are invited to untether themselves from a singular national focus and instead view Germany as a dynamic imagined community - a moveable construct that will continue to evolve as events that occur in one place of the world do not stay contained within borders of nation states drawn on maps.Arts, Faculty ofCentral, Eastern, and Northern European Studies, Department ofGraduat
The Effect of Admixtures on the Buildability of 3D Printed Alkali-Activated Materials with Glass Wool: 3D Printing of Alkali-Activated Materials
No full textResearch about alkali-activated materials or geopolymers has increased in the past decade as they are regarded as a potential replacement to cement-based materials. This is due to the fact that alkali-activated materials possess several advantages over cement-based materials, and the most important one is that they are more sustainable to the environment, as they have less CO2 emissions, less energy consumption during the production process, and the use of byproducts as a binder.The main aim of this work is to develop a mixture that has superior buildability properties with an open time of two hours or more. In order to achieve this, the effect of admixtures, specifically retarders and viscosity modifying admixtures had to be studied. The use of admixtures in geopolymer has been regarded as a complex subject because multiple factors influence their effect on the mixture, like: binders used and their percentages, alkaline activator used, and liquid to binder ratio. In this work, the effect of 3 retarders: sucrose, sodium chloride, and sodium borate on the setting time, flowability, and yield stress development was studied. Moreover, the effect of those retarders was studied with the addition of viscosity modifying admixtures: nano-clay (attapulgite), xanthan gum, sodium carboxymethyl starch, and sodium carboxymethyl cellulose on the same properties.The binders and the alkaline activator used were fixed through out the entire work. the binder composed of 60% fly ash, 20% blast furnace slag, and 20% glass wool. The alkaline activator consists of sodium hydroxide and sodium silicate with a SiO2/Na2O ratio of 1.5. The addition of sucrose didn’t lead to any delay in the setting time. While both sodium chloride and sodium borate delayed the setting time, increased the flowability, and improved the extrudability of the mixtures. Out of the viscosity modifying admixtures, attapulgite had the most positive effect as it improved the thixotropic behaviour of all the mixes and improved the yield stress. Sodium carboxymethyl starch and cellulose almost had the same effect on the all the mixtures as they both improved extrudability and the yield stress in a similar trend. Xanthan gum was considered a poor admixture to be added to this mixture as it led to significant dryness which led to loss in fluidity which affected both flowability and extrudability.The most suitable design was the B3lbA0.5 mixture which has 3% borax and 0.5% attapulgite and a liquid to binder ratio of 0.45. It had an initial setting time of more than 8 hours, flowability was maintained for 2.5 hours and it remained extrudable for 2 hours. Its yield stress ranged from 1360.87 Pa to 1977.78Pa. After 28 days, it had a flexural and compressive strength of 5.72 MPa and 30.42 MPa respectively. Moreover, the flexural and compressive strength of 3D printed prisms was tested in the vertical and horizontal direction on the 7th day. The results showed that the flexural strength of the 3D printed prism tested in the vertical direction was the highest compared to the cast prism and 3D printed prism tested in the horizontal direction by 0.29% and 0.43% respectively. While the compressive strength of 3D printed cube tested in the horizontal direction was higher than both the cast cube and the 3D printed cube tested in the vertical direction by 0.24% and 0.32% respectively. The strength results indicate thatthe mixture could be used in structural applications. The tensile bond strength was 0.69 MPa and the failure occurred near the glue, meaning that the interface is stronger than the material. In 3D printed concrete, usually the interface between the layers is the weakest point, however due to the addition of attapulgite the interface was strengthened. This explains why the compressive strength in the horizontal direction was higher than the vertical one as the interface was no longer the weak link in the specimen. The mixture’s buildability wasn’t optimal as the bottom layer had a slight big deformation and it had onlyten layers of printed material, but that is reasonable since the open time is 2 hours. This means that for big spans this mixture can be useful as it can be printed for a long period of time and its yield stress will develop.In order for the mixture to be printable, it had to have an initial setting time higher than three hours, a spread diameter between 150-200mm and a yield stress above 1400 Pa. The above mentioned resultsfall within the range of values that were needed to have a printable mixture. However, after printing the mixture it was concluded that a spread diameter of 150-180mm and a yield stress above 1600 Pa would be more suitable for both printability and buildability, because when the spread diameter was above180mm and the yield stress was lower than 1600 Pa, the mixture’s viscosity impacted the buildability.Wool2LoopCivil Engineerin
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