Université Mouloud Mammeri de Tizi Ouzou (UMMTO): Research Review of Sciences and Technologies
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Evaluation of fatigue behaviour of bituminous mixtures using a 4-point bending test
Get PDFOne of the key structural failure modes found in bituminous pavement layer is flexural fatigue, resulting from repeated loading application of traffic-induced stresses. It is true that, in recent years, the 4-point bending test (4PBT) have been widely applied in order to characterise fatigue behaviour of asphalt mixtures. In this research paper, the test was used to investigate the fatigue characteristic of one unmodified and two quite different polymer modified asphalt mixtures. The 4PBT results indicated that under the same conditions, an increase trend in flexural stiffness as frequency increased from 1 Hz to 30 Hz for all three mixtures. The test results also presented an obvious difference in the initial stiffness loss behaviour of mixture types tested at 200 microstrain. In addition, in terms of fatigue lines, the 4PBT results showed the polymer modified mixtures have had a better fatigue performance in comparison with the performance of conventional mixtures as expected
Synthèse « sol-gel » des nanocristaux de TiO2 et Ag-TiO2 par dopage direct : Caractérisation et application dans la dégradation du CH3OH.
Get PDFTiO2 and doped Ag-TiO2 nanoparticles have been synthesized via a « sol-gel » technique, starting with titan isopropoxide in the presence of ethanol (≥99,8% purity), of distilled water (at pH = 9) and of ammonium hydroxide (NH4OH 30%). The powders obtained were identified as pure TiO2 and doped Ag-TiO2 through XRD and FTIR methods. The nanoparticles of TiO2 prepared through our procedure compared well with those of the commercial TiO2 (TiO2 Degussa P25) and they were tested in the photocatalytic degradation of methanol.Dans la présente investigation, la photocatalyse hétérogène a été utilisée pour dégrader le CH3OH en phase aqueuse. Pour y parvenir, les nanoparticules de TiO2 pur et de Ag-TiO2 dopé ont été synthétisées par voie « sol-gel », à partir d’un précurseur l’isopropoxyde de titane (pureté ≥ 99,999%) en présence d’éthanol (pureté ≥99,8%), d’eau distillée (pH = 9) et d’ammoniaque (30%). Les poudres synthétisées, ont été identifiées comme du TiO2 pur et dopé Ag-TiO2 par DRX et FTIR. Les nanopoudres synthétisées exhibent une cristallisation à 87,2% anatase et 12,8% rutile à 700 °C, cette composition dépasse le taux d’anatase de TiO2 P25 « Degussa P25 » commercial dont la cristallisation est à 80 % anatase + 20 % rutile. En outre ces nanopoudres intrinsèque et extrinsèque se sont révélées très efficaces dans la photodégradation du CH3OH mais celle-ci était plus importante en utilisant la poudre dopée (Ag-TiO2) à cause d’une action synergique entre le TiO2 et des propriétés catalytiques propres du métal, qui augmente la conductivité du semi-conducteur (TiO2). Les nanocristaux de TiO2 préparés ont révélé une dégradation un peu plus quantitative que le TiO2 P25 « Degussa P25 » due à son taux élevé en anatase
Research on heat resistance of A60 fire-resistant doors used on ships using CFD numerical simulation
Get PDFTypically, the design of fire doors on ships is mainly to meet thermal requirements, while thermal deformation can also significantly affect the safety performance of the door. When the fire temperature is high, the door tends to warp and deviate from the supporting frame due to uneven temperature distribution, which may lead to the spread of fire and smoke on ships. To evaluate their performance, fire doors must undergo a standardized fire test. Realistic simulation of this fire test can be of great benefit during the design phase in order to reduce the number of prototypes to be manufactured and tested. This article researches the testing process of A60 fire-resistant doors installed on ships. The A60 fire-resistant door consists of two steel plates, each measuring 1600x600x45 mm, with a 42 mm thick layer of mineral wool insulation placed between them. Test sample were heated in a gas-fired furnace for 60 minutes. The findings are given in the form of a temperature-time chart showing that the test sample meets the requirements for fire-resistant doors used for ships. This study holds significant importance for the development of the shipbuilding industry in Vietnam in the near future
Behaviour of arched hybrid sustainable precast deep beams including green Concrete
Get PDFIn recent years, the use of waste construction materials in the production of sustainable and cost-effective structural members such as deep beams has become more interesting. In the present work, a new sustainable model of a hybrid deep beam has been proposed and compared with the Horizontally hybrid model. Nine specimens have been tested experimentally under mid-span static loading up to failure. The arch region of the proposed model is made of steel fiber concrete (SFC), while other regions are made of concrete with recycled coarse aggregate (RCA) with three ratios of replacement (0%, 50%, and 100%). The specimens are grouped in three sets, each with three specimens representing the conventional model, the proposed model (ARC1), and the modified model (ARC2). The response has been studied in terms of cracking load, failure load, crack width, cracking pattern, and toughness. Results revealed that the proposed model ARC1 enhanced capacity by 6.7%, 6.8%, and 9.4% compared to the conventional hybrid model for the three value of RCA. While for the model ARC2 capacity improved by 13.5%, 19.6%, and 19.1. Regarding the toughness, enhancements of 12.5%, 18.7%, and 32.9% were obtained for the model ARC1 compared to the traditional hybrid model. While for model ARC2, it is enhanced by 25.2%, 51.1%, and 62.1% respectively. The proposed hybrid models may contribute in reduction the cost of construction and reduce the environmental effects of the waste of construction materials
Assessing sustainability performance by applying the TOPSIS method in road construction projects
Get PDFThe sustainability of road development projects must be evaluated holistically. These guarantees roads are constructed to endure fluctuating climatic circumstances and decreasing overall costs and environmental implications. Establishing a comprehensive methodology and framework to evaluate the sustainability level of infrastructure investment projects is crucial. This study presents a methodology that combines the Life Cycle Approach with the TOPSIS technique to conduct a comprehensive assessment of the sustainability level. The social, conventional environmental, and economic implications were initially evaluated through a life cycle method. The TOPSIS technique was subsequently utilized to rank the alternatives according to the metrics obtained from these evaluations. For validation, three pavement options in a project are compared to select the most sustainable alternative by using the proposed integrated TOPSIS technique. The results signify that option Y3 has superior sustainability performance relative to Y1 and Y2. Consequently, option 3 (normal Asphaltic Concrete) emerges as the most sustainable selection among the evaluated choices
تحليل الخطاب النقدي لرواية «ريح الجنوب» لعبد الحميد بن هدوقة معتمداً علی نظرية «نورمن فرکلاف»
No full textCritical discourse analysis as a modern methods of text analysis, helps us in a deep understanding of the text and of the links between textual elements. This research analyzes the Algerian novel "The Wind of the South", dealing with social problems after the earth reforms. In this study based on the descriptive and analytical method, adopting the critical discourse analysis of Fairclough, the researcher tried to reach the deep layers of the text, and to reveal the link between power and ideology. The research results indicated the existence of dialectical and bilateral links between language and authority, as the language used in this novel reveals the extent of the characters' possession of power. The rotation system of the characters decreases with decreament of their power. The contrasts led to the creation of a special structure for the village community, and thus could lead to a change in the society structure. Studying the problems of “Nafeeseh” one of the original characters, introduces the addressee to contrast between the city, the symbol of life, and the village, the symbol of death
التداولية وعلاقتها بالحقول المعرفية الأخرى
No full textIn this research, we aim to review: “the Pragmatics and its relationship with other surrounding fields of knowledge , such as linguistics, philosophy, mathematics, logic, psychology, sociology, literature, discourse analysis ... and others. This paper aims to identify the epistemological references that contributed to the establishment and development of the pragmatic thought, and Determining its general features within different fields of knowledge. Through this paper, we will try to answer the following questions: - Does pragmatics interfere with other fields? - What is the nature of the relationship between pragmatics and other fields close to it? And how that openness contributed to building its concepts? - What are the limits of interfering between pragmatics and other knowledgement fields
Les zones d’ombre du phénomène de la définition et l’acte de définir : Le cas de la langue Amazighe (Kabyle)
Get PDFThe idea of the definition of words and/or things has sown through its evolution a certain doubt in the eyes of many specialists, whether in philosophy or in the sciences of language. However, many writings have tried to situate this problem despite the difference in schools to which they relate. Thus, this work will be devoted to the study of the elements that contribute to the construction of the definition resulting from natural languages. The anchoring of the definition and its structure leads us to question the nature of the status of the elements that compose it, in this case: the defined and the defining statement.The instruments allowing the definition to take root in the discourse of the users or the lexicographer follow a rather singular process in the birth of a defining statement. This nascent definitional discourse is subordinated to the language capital of each other, but in both cases are necessarily subjective
مناهج النقد الأدبي والجدل الثقافي، مطارحة أبستمولوجية حول "الوظيفة الجمالية البنيوية" و"الهجنة الثقافية ما بعد البنيوية" أنموذجا.
No full textTraditional criticism has previously taken care of the issue of dialectical dualism as a language - thought and its relationship to the acquisition of knowledge on the literary and critical levels, meaning which is earlier and first than the other without producing a decisive conclusion towards them, and we believe that traditional criticism would not have been eager for the emergence of the tendency of structural criticism and then post-structural criticism Had it not been for his failure in this issue of decisiveness, from this point of view he tries to research an argument and not an approach to resurrect the issue again at the level of the most accurate unit or sensitive element within two critical schools that are not completely different, but they are a scientific breakthrough for one of them on the ruins of the other, namely the "structural aesthetic function" or (structuralism). Functionalism) in the critical literary and structural lesson and the "cultural hybrid" in the post-structuralist critical and literary lesson, which we think that both constitute an epistemological stage in the theory of criticism and the theory of literature and the steady scientific and cognitive progress that resists stability and isolation, that is, both of them are an epistemological effort towards the search for what literature and criticism are. The real ones, as our discussion will reveal the paradox or the dialectical deficiency of both models to complement them, for they need someone to complement them on the level of their principles, procedural foundations, and forbidding. Jh; Neither the language of the dryness of imagination and abstraction is of criticism and literature that has completed epistemological circles, nor the content tendency that is not dependent on the aesthetics of the language statement that would curb the ferocity of the self and its extreme wildness are likewis
Flexural and Shear Performance of the Reinforced Beams made of Geopolymer Concrete: A review
Get PDFGeopolymer is known to have many structural and nonstructural benefits, but the attractive characteristic of this novel material is that it depends essentially on a byproduct from different industries, and the use of Portland cement is absent. This concrete is an environmentally friendly product and is essential as the sustainability issue is considered. Compared with the material properties, the behavior of reinforced concrete members made of geopolymer has gained less importance by past researchers. Therefore, this review paper aims to summarize the evidence of the structural behavior of geopolymer concrete beams to provide a better understanding of the characteristics of reinforced geopolymer beams. A total of sixteen published works on geopolymer beams reinforced with steel rebar have been reviewed, and it found that there are 83 beams tested in flexure and 29 beams tested to highlight the shear behavior. For comparison, some researchers have tested control beams made of Portland cement concrete (PCC). It is noted that geopolymer concrete (GPC) beams have a performance, in general, better than that of PCC beams in terms of strength and ductility. Design proposals for PCC beams could be safely used for GPC beams, and the software based on the finite element method accurately predicts the load-deflection response. However, further study is recommended to provide more detailed and cost-effective design methodologies for the potential use of GPC in large-scale field applications