Partial Confinement Utilization for Rectangular Concrete Columns Subjected to Biaxial Bending and Axial Compression

Citation: Abd El Fattah, A. M., Rasheed, H. A., & Al-Rahmani, A. H. (2017). Partial Confinement Utilization for Rectangular Concrete Columns Subjected to Biaxial Bending and Axial Compression. International Journal of Concrete Structures and Materials, 11(1), 135-149. doi:10.1007/s40069-016-0178-zThe prediction of the actual ultimate capacity of confined concrete columns requires partial confinement utilization under eccentric loading. This is attributed to the reduction in compression zone compared to columns under pure axial compression. Modern codes and standards are introducing the need to perform extreme event analysis under static loads. There has been a number of studies that focused on the analysis and testing of concentric columns. On the other hand, the augmentation of compressive strength due to partial confinement has not been treated before. The higher eccentricity causes smaller confined concrete region in compression yielding smaller increase in strength of concrete. Accordingly, the ultimate eccentric confined strength is gradually reduced from the fully confined value f(cc) (at zero eccentricity) to the unconfined value f(c)(1) (at infinite eccentricity) as a function of the ratio of compression area to total area of each eccentricity. This approach is used to implement an adaptive Mander model for analyzing eccentrically loaded columns. Generalization of the 3D moment of area approach is implemented based on proportional loading, fiber model and the secant stiffness approach, in an incremental-iterative numerical procedure to achieve the equilibrium path of P-epsilon and M-phi response up to failure. This numerical analysis is adapted to assess the confining effect in rectangular columns confined with conventional lateral steel. This analysis is validated against experimental data found in the literature showing good correlation to the partial confinement model while rendering the full confinement treatment unsafe

Electron refraction at lateral atomic interfaces

We present theoretical simulations of electron refraction at the lateral atomic interface between a “homogeneous” Cu(111) surface and the “nanostructured” one-monolayer (ML) Ag/Cu(111) dislocation lattice. Calculations are performed for electron binding energies barely below the 1 ML Ag/ Cu(111) M-point gap (binding energy EB ¼53 meV, below the Fermi level) and slightly above its C -point energy (EB ¼160 meV), both characterized by isotropic/circular constant energy surfaces. Using plane-wave-expansion and boundary-element methods, we show that electron refraction occurs at the interface, the Snell law is obeyed, and a total internal reflection occurs beyond the critical angle. Additionally, a weak negative refraction is observed for EB ¼53 meV electron energy at beam incidence higher than the critical angle. Such an interesting observation stems from the interface phase-matching and momentum conservation with the umklapp bands at the second Brillouin zone of the dislocation lattice. The present analysis is not restricted to our Cu-Ag/Cu model system but can be readily extended to technologically relevant interfaces with spinpolarized, highly featured, and anisotropic constant energy contours, such as those characteristic for Rashba systems and topological insulators. Published by AIP Publishing.Peer ReviewedPostprint (published version

Effect of physical therapy rehabilitation program (exercise-therapy) on Irritable Bowel Syndrome

To evaluate the effect of physical therapy rehabilitation program consisted of moderate intensity aerobic exercise training (60% MHR) (Maximum Heart Rate) treadmill training on irritable bowel syndrome (IBS) symptom and quality of Life in post cholecystectomy patients. Thirty post cholecystectomy patients complaining from irritable bowel syndrome were recruited for this study; age ranged from 25 to 40 years, Patients were divided randomly into two equal groups, Group (A): received 4 weeks moderate intensity aerobic training program (60% MHR treadmill training (3 sessions per week) plus routine medical treatment protocol, Group (B): received routine medical care only. Patients assessed by Irritable Bowel Syndrome Symptom Severity Score (IBS-SSS) and Irritable Bowel Syndrome Quality of Life (IBS-QOL), Assessment was carried out before treatment and 4 weeks after treatment in both groups. Results showed that there was a significant decrease in post treatment values of IBS-SSS and IBS-QOL in comparison to pre-treatment values at both groups with (p-value < .001). Comparison between both groups post treatment showed significant difference in IBS-SSS and IBS-QOL variables, in group (A) more than group (B). Moderate intensity aerobic exercise training (60% MHR) for 4 weeks is effective in treatment of IBS post cholecystectomy through reducing IBS symptoms and improving Quality of Life

Changes in composition of colostrum of Egyptian buffaloes and Holstein cows

<p>Abstract</p> <p>Background</p> <p>Changes in colostrum composition of Egyptian buffaloes and Holstein cows collected at calving, 6, 12, 24, 48, 72, 96, 120 h and after 14 days of parturition were studied. Total solids, total protein, whey proteins, fat, lactose and ash contents were determined. Macro- and micro-elements, IgG, IgM, IGF-1, lactoferrin and vitamins (A and E) were also estimated.</p> <p>Results</p> <p>At calving, the total protein and whey proteins concentration did not differ between buffalo and cow colostrum, while total solids, fat, lactose and ash concentrations were higher in buffalo than in cow colostrum. All components decreased gradually as the transition period advanced except lactose which conversely increased. On the fifth day post-partum, concentration of total protein, whey proteins, fat, ash and total solids decreased by 69.39, 91.53, 36.91, 45.58 and 43.85% for buffalo and by 75.99, 94.12, 53.36, 33.59 and 52.26% for cow colostrum. However, lactose concentration increased by 42.45% for buffalo and 57.39% for cow colostrum. The macro-and micro-elements concentration of both colostrums tended to decline slightly toward normality on the fifth day of parturition. Buffalo colostrum had a higher concentration of vitamin E than cow colostrum during the experimental period. At calving, the concentration of vitamin A in buffalo colostrum was found to be approximately 1.50 times lower than in cow colostrum. The concentrations of IgG, IgM, IGF-1 and lactoferrin decreased by 97.90, 97.50, 96.25 and 96.70% for buffalo and 76.96, 74.92, 76.00 and 77.44% for cow colostrum, respectively after five days of parturition.</p> <p>Conclusions</p> <p>There is a dramatic change in buffalo and cow colostrum composition from the first milking until the fifth day of parturition. There are differences between buffalo and cow colostrum composition during the five days after calving. The composition of both colostrums approaches to those of normal milk within five days after parturition.</p

Synthesis and efficiency of new pyridine, chromene and thiazole containing compounds as antimicrobial and antioxidant agents

ABSTRACT. The versatile scaffold, N'-(2-cyanoacetyl)-2-hydroxybenzohydrazide (3) was utilized in the production of new pyridine, chromene and thiazole derivatives as antimicrobial and antioxidant agents. The synthetic strategy involves the treatment of precursor 3 with various arylidene-malononitrile and 3-aryl-2-cyanoacrylate compounds to furnish substituted pyridines 5 and 7. The interaction of 3 with salicylaldehyde and/or phenyl isothiocyanate followed by cyclization with chloroacetone produced the corresponding 2-imino-2H-chromene-3-carbohydrazide and (thiazol-2-ylidene-acetyl)-salicylic acid hydrazide compounds 8 and 9, respectively. The structural features of the synthesized compounds were confirmed by using spectroscopic methods such as (IR, 1H NMR, 13C NMR and MS). The new pyridine, chromene and thiazole products showed potent antioxidants and antimicrobial activities. The thiazole derivative 9 exhibited the highest anti-bacterial and antifungal activities against S. aureus (75.0%) and B. subtilis (73.9%) and C. albicans (66.6%). The combination between salicylic acid hydrazide and thiazole moieties in the hybrid 9 indicated the best antioxidant activity (87.9%). &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; KEY WORDS: Salicylic hydrazide, Arylidene-malononitrile, Pyridine, Thiazole, Antioxidant &nbsp; Bull. Chem. Soc. Ethiop. 2022, 36(1), 137-148.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; DOI: https://dx.doi.org/10.4314/bcse.v36i1.12&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp