Analysis of earth dam-flexible canyon interaction by 3D hybrid FEM-SBFEM

La géométrie et la flexibilité d'un canyon sont les paramètres qui affectent grandement la valeur des périodes naturelles dans les barrages en terre. Le canyon entourant des barrages peut être considéré comme un domaine illimité. Pour prendre en compte ces deux effets, le canyon a été modélisé par SBFEM et le barrage en terre, à géométrie limitée, par FEM. La technique hybride SBFEM-FEM pour l'analyse tridimensionnelle dynamique de l'interaction sol-barrage a été validée avec les résultats disponibles dans la littérature. Comme la matrice de rigidité dynamique du domaine non borné est complexe et dépendante de la fréquence, la méthode classique de superposition de modes n'est pas simple pour le système d'interaction sol-structure. Ainsi, pour obtenir la fréquence propre fondamentale, le barrage a été excité en direction amont-aval. Les périodes naturelles du barrage de terre pour des canyons de formes géométriques et de coefficient de impédance différents ont été obtenues. Ils se sont avérés avoir des effets significatifs sur la période naturelle. Les résultats ont été comparés aux données enregistrées réelles. Il a été constaté que les graphiques proposés dans cette étude peuvent être utilisés par des concepteurs de barrages pour l'estimation des périodes naturelles des barrages en terre dans des canyons de formes et de propriétés matérielles différentes. Plusieurs fonctions d'amplification correspondant à différentes conditions de canyon ont été obtenues en appliquant un déplacement uniforme à la limite du canyon. Une étude approfondie a été réalisée pour examiner les effets de la géométrie et de la flexibilité du canyon sur la réponse en régime permanent du barrage. Ces deux effets ont influencé de manière importante les fonctions d'amplification. Alors que la flexibilité du canyon affecte de manière significative la valeur de la fonction d'amplification maximale, cette valeur ne change pas pour les barrages en terre dans lesquels les canyons ont des formes différentes et la même longueur. De plus, la réponse latérale du barrage de terre dans le domaine temporel a été calculée pour analyser les effets susmentionnés lors d'un tremblement de terre réel. Les fonctions d'amplification proposées ont été utilisées pour comparer les spectres de réponse enregistrés du barrage d'El Infiernillo lors des tremblements de terre de 1966 avec la fonction d'amplification calculée. Un accord raisonnable a été observé entre eux. La méthode linéaire équivalente (EQL) a été implémentée dans le FEM. La technique FEMSBFEM a été étendue pour prendre en compte l'effet du comportement non linéaire des barrages en terre. Il a été observé que le comportement non linéaire affecte grandement la fréquence naturelle, la fonction d'amplification et l'accélération de crête maximale du barrage de terre situé dans les canyons. Les effets de la géométrie et de la flexibilité du canyon sur le comportement non linéaire ont été examinés, et on a vu qu'en augmentant la flexibilité du canyon, l'effet de la non-linéarité était diminué. Le barrage d'El Infiernillo a été modélisé par FEM-SBFEM non linéaire 3D, et une comparaison de la fonction d'amplification de crête obtenue par la méthode proposée avec les données enregistrées montre la précision du FEM-SBFEM non linéaire.The canyon surrounding a dam can be assumed as an unbounded domain, and the geometry and flexibility of a canyon are parameters that greatly affect the values of natural periods in earth dams. In this thesis, in order to take into account these two effects, canyons are modeled by SBFEM, and earth dams, which have limited geometries, are modeled by FEM. The hybrid FEM-SBFEM technique used for the dynamic three-dimensional analysis of soil-earth dam interactions is validated with results available in the literature. Because the dynamic-stiffness matrix of the unbounded domain is complex and frequency-dependent, the classical mode-superposition method is not straightforward for a soil-structure interaction system, and thus, to obtain their fundamental natural frequencies, the modeled dams were excited in the upstream-downstream direction. The natural periods of earth dams in canyons with different geometries shapes and impedance ratios are obtained, and are found to have significant effects on the dams' natural periods. The results are compared with actual recorded data, and it is found that the graphs put forward in this study may be used by practical engineers for the estimation of natural periods of earth dams in canyons with different shapes and material properties. Several amplification functions corresponding to different canyon conditions are obtained by applying a uniform displacement at the canyons' boundaries. A comprehensive study is performed to examine the effects of canyon geometry and flexibility on the steady-state responses of the dams, and it is found that these two effects significantly influence the amplification functions. While the flexibility of the canyon does affect the maximum amplification function value, this value does not change for earth dams in canyons that have different shapes but the same length. In addition, the lateral responses of earth dams in the time domain are computed in order to analyze the aforementioned effects under an actual earthquake. The proposed amplification functions are used to compare the recorded response spectra of the El Infiernillo dam under the two 1966 earthquakes with the calculated amplification function, and a reasonable agreement is observed between them. The equivalent linear method (EQL) is implemented into the FEM, and the FEM-SBFEM technique is extended in order to take into consideration the effect of earth dams' nonlinear behavior. It is observed that such nonlinear behavior greatly affects the natural frequency, the amplification function, and peak crest acceleration of earth dams located in canyons. The effects of canyon geometry and flexibility on the nonlinear behavior are examined, and it is found that by increasing canyon flexibility, the effect of nonlinearity is decreased. The El Infiernillo dam is modeled by the 3D nonlinear FEM-SBFEM, and comparison of the crest amplification function obtained by the proposed method with the recorded data shows the accuracy of the nonlinear FEM-SBFEM

CO2 wettability of rock and implications for core-flooding

Rock became more CO2 wet with increasing pressure, temperature and brine salinities and less CO2 wet with increasing surface roughness - i.e. a lower storage capacity can be inferred for structural trapping. Moreover, we demonstrate that gas densities correlate remarkably well with wettability also a physical model was developed to provide a theoretical framework. Furthermore, the permeability of sandstone samples reduced after injection of brine, CO2-saturated brine or supercritical CO2 at reservoir conditions

Assignment integration in order to achieve the successful studio-based education (An Idea Implementation of Integrated Architecture Experiential Learning)

The formal architecture undergraduate degree (S1) is determined by taking total 144 credits, in 8 semesters (4 years). After he/she graduated and earn the B.Arch, to become a professional architect one must take 1-2 year’s professional diploma including internship in one architectural bureau. All this limitations may cause several strategies such as a curriculum adjustment in order to meet all the teaching materials needed. Those strategies includes; eliminating some subjects that considered not necessary, decreasing the teaching materials content in order to create lesser credits so more subjects may be added into the curriculum, or merging some subjects into a new subject and adding more credits into it. This condition affecting the learning objective of the new subject cannot be achieved optimally. Seeing this tendency, an idea has emerged by integrating some of the subjects’ assignments into one comprehensive assignment. This concept is derived into scenarios that a student will undergo a one big assignment containing materials from several subjects, and the scoring phase will be examined from several subjects’ point of views. This paper will discuss the effectiveness of architecture subject assignment integration, in this case the architecture design studio as the core of architecture education with other supporting subjects including the theoretical subjects, to achieve architecture education’s target and objective. Methodology of research used is qualitative research through observation methods: (1) Condition of the studio assignments with other supporting subjects (theory and skill) assignments that can be integrated, (2) Strategy to achieve the learning objective target through the integration of the studio assignments with other subjects' assignments, (3), Advantage and disadvantage of the assignments’ integration scenario. Hopefully the result of the integration of the studio assignments with other subject's assignments can achieve the successful architecture education, effective, target fulfilled, and optimize

Improving basalt wettability to de-risk CO2 geo-storage in basaltic formations

CO2 geo-storage in basaltic formations has recently been identified as a viable option to rapidly dispose large quantities of CO2, hence mitigating anthropogenic CO2 emissions. However, it has been shown that basalt is weakly water-wet or intermediate-wet at typical storage conditions, which reduces capillary trapping capacities and increases lateral and vertical spreading of the CO2 plume; and these effects increase project risk. We thus propose here to prime basalt surfaces with anionic surfactant (here we used sodium dodecyl benzene sulfonate), and demonstrate that such priming is highly efficient, and renders the basalt completely water-wet even at high pressures and minute sodium dodecyl benzene sulfonate concentrations. Such a wettability alteration can therefore significantly de-risk storage projects. This work aids in the improvement of CO2 storage in basaltic formations and supports implementation of industrial-scale CO2 geo-sequestration and climate change mitigation

Is Noncycloplegic Photorefraction Applicable for Screening Refractive Amblyopia Risk Factors?

Purpose: To compare the accuracy of noncycloplegic photorefraction (NCP) with that of cycloplegic refraction (CR) for detecting refractive amblyopia risk factors (RARFs) and to determine cutoff points. Methods: In this diagnostic test study, right eyes of 185 children (aged 1 to 14 years) first underwent NCP using the PlusoptiX SO4 photoscreener followed by CR. Based on CR results, hyperopia (≥ +3.5 D), myopia (≥ -3 D), astigmatism (≥ 1.5 D), and anisometropia (≥ 1.5 D) were set as diagnostic criteria based on AAPOS guidelines. The difference in the detection of RARFs by the two methods was the main outcome measure. Results: RARFs were present in 57 (30.8%) and 52 (28.1%) of cases by CR and NCP, respectively, with an 89.7% agreement. In contrast to myopia and astigmatism, mean spherical power in hyperopic eyes was significantly different based on the two methods (P < 0.001), being higher with CR (+5.96 ± 2.13 D) as compared to NCP (+2.37 ± 1.36 D). Considering CR as the gold standard, specificities for NCP exceeded 93% and sensitivities were also acceptable (≥ 83%) for myopia and astigmatism. Nevertheless, sensitivity of NCP for detecting hyperopia was only 45.4%. Using a cutoff point of +1.87 D, instead of +3.5 D, for hyperopia, sensitivity of NCP was increased to 81.8% with specificity of 84%. Conclusion: NCP is a relatively accurate method for detecting RARFs in myopia and astigmatism. Using an alternative cutoff point in this study, NCP may be considered an acceptable device for detecting hyperopia as well

Long-term visual outcome of congenital cataract at a Tertiary Referral Center from 2004 to 2014

AbstractPurposeTo assess the long-term visual acuity (VA) outcome after congenital cataract surgery at Imam Hossein Medical Center (Tertiary Referral Center) (2004–2014).MethodsIn this descriptive study, records of 120 patients with a history of congenital cataract surgery were studied. Those with traumatic, metabolic cataract, aged <5 years at the last visit who were not able to respond VA testing accurately and follow-up < 6 months were excluded. Cases with incomplete files were recalled and reexamined. Finally, the records of 42 patients (71 eyes) were included.ResultsIn this study, 20 males and 22 females with a mean age of 11.80 ± 6 years at their last visit were studied. Bilateral and unilateral cataract was seen in 69% and 31% of cases, respectively. Posterior and anterior subcapsular opacity was the most common (53.70%) and rarest (1.90%) type of congenital cataract, respectively. The mean age at the time of operation and surgical interval was 65 ± 66.6 (range: 1–200) and 12.9 ± 23.5 (range: 0–96) months, respectively. The most common method of refractive error correction was pseudophakia plus glasses (56.3%) with the mean best corrected visual acuity (BCVA) of 0.29 ± 0.28 LogMAR., The mean BCVA was 0.7 ± 0.53 LogMAR for aphakic patients correcting by glasses. In our study, amblyopia (56%), glaucoma (23.90%), and posterior capsular opacity (16.40%) were observed during their follow-ups on an average of 76 ± 65 months (median: 60, range: 6–240). Unilateral cataract, aphakia, nystagmus, female gender, and strabismus were risk factors of VA loss.ConclusionBased on our results, 56% of cases showed amblyopia. It could be due to late operation (especially in unilateral cases), longer surgical interval between two eyes, and no compliance of amblyopia therapy. Early detection through screening may reduce the rate of amblyopia. Refractive errors, visual acuity, amblyopia, glaucoma, posterior capsular opacity, and compliance of amblyopia therapy should be checked regularly at follow-up visits

Major Dietary Patterns Relationship with Severity of Coronary Artery Disease in Gaza-Strip, Palestine: A Cross-Sectional Study

BACKGROUND፡ The association of dietary patterns (DPs) linked to the severity of coronary artery disease (CAD) is little known. Therefore, this study aims to explore the relationship between major DPs and the severity of CAD.METHODS: This cross-sectional study was conducted among423 newly discovered CAD patients (both genders, aged 35-65 years), who underwent coronary angiography. The severity of CAD was assessed by the Gensini score. All patients were tested using a semi-quantitative food frequency questionnaire and other related data through face-to-face interviews. Factor analysis and logistic regression were applied by using SPSS version-24.RESULTS: By principal component analysis, two major DPs were identified: “Unhealthy” DP that characterized mainly by high intakes of sugar and sweets, soft drinks, salts, cooking oils, and processed meats, and “Healthy” DP that consisting high intakes of fruits, fish, poultry, vegetables, whole grains. After adjustment for confounding variables, the odds of severe CAD was significantly higher in the third (T3) and second (T2) tertile of the unhealthy pattern by 4.79 and 2.48 times more compared to the first tertile (T1) (OR 4.79; 95%CI 2.60, 8.83; P&lt;0.001) and (OR 2.48; 95%CI 1.40, 4.39; P=0.002), respectively. However, the odds of CAD severity in the T3 and T2 of the healthy pattern was lowered by 0.24 and 0.38 times less compared to the T1 (OR 0.24; 95%CI 0.12, 0.47; P=0.002) and (OR 0.38; 95%CI 0.20, 0.73;P=0.006), respectively.CONCLUSION: The severity of CAD was significantly increased by the unhealthy dietary pattern, while decreased by adherence to the healthy pattern