Dynamic soil-structure interaction analysis using the scaled boundary finite-element method.

This thesis presents the development of a reliable and efficient technique for the numerical simulation of dynamic soil-structure interaction problems in anisotropic and nonhomogeneous unbounded soils of arbitrary geometry. Such a technique is indispensable in the seismic analysis of large-scale engineering constructions and, to my best knowledge, does not exist at present. The theoretical framework of the research is based on the scaled boundary finite-element method. The following advances are achieved: The scaled boundary finite-element method is extended to simulate the dynamic response of non-homogeneous unbounded domains. The scaled boundary finite element equations in the frequency and time domains are derived for power-type non-homogeneity frequently employed in geotechnical engineering. A high-frequency asymptotic expansion of the dynamic-stiffness matrix is developed. The frequency domain analysis is performed by integrating the scaled boundary finite-element equation in dynamic stiffness. In the time domain, the scaled boundary finite-element equation including convolution integrals is solved for the unit-impulse response at discrete time stations. A Padé series solution for the scaled boundary finite-element equation in dynamic stiffness is developed. It converges over the whole frequency range as the order of the approximation increases. The computationally expensive task of numerically integrating the scaled boundary finite-element equation is circumvented. Exploiting the sparsity of the coefficientmatrices in the scaled boundary finite-element equation leads to a significant reduction in computer time and memory requirements for solving large-scale problems. Furthermore, lumped coefficient matrices are obtained by adopting the auss-Lobatto-Legendre shape functions with nodal quadrature, which avoids the eigenvalue problem in determining the asymptotic expansion. A high-order local transmitting boundary constructed from a continued-fraction solution of the dynamic-stiffness matrix is developed. An equation of motion as occurring in standard structural dynamics with symmetric and frequency-independent coefficient matrices is obtained. This transmitting boundary condition can be coupled seamlessly with standard finite elements. Transient responses are evaluated by using a standard timeintegration scheme. The expensive task of evaluating convolution integrals is circumvented. The advances developed in this thesis are applicable in other disciplines of engineering and science to the analysis of scalar and vector waves in unbounded media

Optimal 6E design of an integrated solar energy-driven polygeneration and CO2 capture system: A machine learning approach

Renewable energy-driven decentralized polygeneration systems herald great potential in tackling climate change issues and promoting sustainable development. In this light, this study introduces a new machine learning-based multi-objective optimization approach of an integrated solar energy-driven polygeneration and CO2 capture system for meeting a greenhouse’s power, freshwater, and CO2 demands. The integrated solar-assisted polygeneration system comprises a 486-kW gas turbine, two steam turbines, two organic Rankine cycles, a humidification-dehumidification desalination unit to recover waste heat while producing freshwater, and a post-combustion CO2 capture unit. The proposed system is mathematically modelled and evaluated via a dynamic simulation approach implemented in MATLAB software. Moreover, sensitivity analysis is conducted to identify the most influential decision variables on the system performance. The machine learning-based multi-objective optimization strategy combines Genetic Programming (GP) and Artificial Neural Networks (ANN) to minimize total costs, environmental impacts, and economic and environmental emergy rates whilst maximizing the system exergy efficiency and freshwater production. Finally, the system performance is further investigated through comprehensive Energy, Exergy, Exergoeconomic, Exergoenvironmental, Emergoeconomic, and Emergoenvironmental (6E) analyses. The three-objective optimization of the integrated system reduces total costs, environmental impacts, and monthly environmental emergy rate by 11.4%, 34.31% and 6.38%, respectively. Furthermore, reductions up to 56.81%, 50.19% and 77.07%, respectively, are obtained for the previous indicators by the four-objective optimization model. Hence, the proposed multi-objective optimization methodology represents a valuable tool for decision-makers in implementing more cost-effective and environment-friendly solar-assisted integrated polygeneration and CO2 capture systems

Prevalence of helminth parasites in digestive tract of Persian sturgeon (Acipenser persicus) broodstocks southeast of the Caspian Sea

We collected 100 specimens of Persian sturgeon brood stocks propagated in Shahid Marjani Fish Culture Center to study internal parasites during March, April and May 2005. The center is located in the southeast of the Caspian Sea. Three different parasite species were recovered from digestive tract (stomach and intestine) of the fish. Cucullanus sphaerocephalus, Skrjabinopsolus semiarmatus showed the highest incidence and highest mean intensity (with prevalence of 80% and 55% respectively) but Leptorhynchoides plagicephalus had the lower prevalene 2 %. The prevalence of S. semiarmatus and C. sphaerocephalus were higher in males than in females whereas the intensity of these parasites was higher in females than in males. Statistical analysis of data showed a significant relationship between the occurrence of S. semiarmatus and the sex of the fish. There was a significant relationship between the occurrence of C. sphaerocephalus and the length of the fish (P 6 0.05). Forty nine percent of the fish had less than 10 worms. It was also found that the internal parasites of A. persicus in the southeast of the Caspian Sea are the same as those found in the southwest but the diversity of parasites were fewer in the former

Prevalence and Correlates of Hepatitis C Infection among Male Injection Drug Users in Detention, Tehran, Iran

For the benefit of planning for the future care and treatment of people infected with hepatitis C virus (HCV) and to help guide prevention and control programs, data are needed on HCV seroprevalence and associated risk factors. We conducted a cross-sectional sero-behavioral survey of injection drug users (IDU) detained for mandatory rehabilitation during a police sweep of Tehran, Iran, in early 2006. During the study period, a consecutive sample comprising 454 of 499 (91.0%) men arrested and determined to be IDU by urine test and physical examination consented to a face-to-face interview and blood collection for HCV antibody testing. Overall, HCV prevalence was 80.0% (95% confidence interval (CI) 76.2–83.6). Factors independently associated with HCV infection included history of incarceration (adjusted OR 4.35, 95% CI 1.88–10.08), age of first injection ≤25 years (OR 2.72, 95% CI 1.09–6.82), and history of tattooing (OR 2.33, 95% CI 1.05–5.17). HCV prevalence in this population of IDU upon intake to jail was extremely high and possibly approaching saturation. Findings support that incarceration is contributing to the increased spread of HCV infection in Iran and calls for urgent increased availability of HCV treatment, long-term preparation for the care of complications of chronic infection, and rapid scale-up of programs for the primary prevention of parenterally transmitted infections among drug users

Preliminary results of paleoseismological trenching along the Astaneh fault

The Astaneh fault with a length of more than 75 km is located in NW of Damghan. Morphotectonic investigation along the Astaneh fault and left - lateral displacement in quaternary deposits shows that, Astaneh is an active fault. It is necessary to recognize paleoseismicity of Astaneh fault because, this fault is located in seismic zone of Komes historical earthquake with Ms=7.9 (Ambraseys & Melville, 1982). Many people (more than 45000) were killed in Damghan city in Komes historical earthquake. In this paper, 4-5 paleo events along the Astaneh fault are presented through paleoseismological investigation

Melkersson–Rosenthal syndrome in the context of sarcoidosis: a case report

Background!#!Melkersson-Rosenthal syndrome is a rare disease characterized by the triad of recurrent orofacial swelling with facial paralysis and fissured dorsal tongue. Histologically, noncaseating granulomatous inflammation occurs that confirms the diagnosis. Overlaps between granulomatous diseases such as sarcoidosis and Crohn's disease are described. Systemic corticosteroid therapy is the treatment of choice for acute attacks.!##!Case presentation!#!We here present a case of a 59-year-old White woman suffering from Melkersson-Rosenthal syndrome with a past history of sarcoidosis on therapy with leflunomide in combination with low-dose tacrolimus successfully treated with the anti-leprosy drug clofazimine after failure of systemic steroid therapy.!##!Conclusions!#!We propose clofazimine as an alternative treatment in steroid-refractory cases