A priori testing of sparse adaptive polynomial chaos expansions using an ocean general circulation model database

This work explores the implementation of an adaptive strategy to design sparse ensembles of oceanic simulations suitable for constructing polynomial chaos surrogates. We use a recently developed pseudo-spectral algorithm that is based on a direct application of the Smolyak sparse grid formula and that allows the use of arbitrary admissible sparse grids. The adaptive algorithm is tested using an existing simulation database of the oceanic response to Hurricane Ivan in the Gulf of Mexico. The a priori tests demonstrate that sparse and adaptive pseudo-spectral constructions lead to substantial savings over isotropic sparse sampling in the present setting.United States. Office of Naval Research (award N00014-101-0498)United States. Dept. of Energy. Office of Advanced Scientific Computing Research (award numbers DE-SC0007020, DE-SC0008789, and DE-SC0007099)Gulf of Mexico Research Initiative (contract numbers SA1207GOMRI005 (CARTHE) and SA12GOMRI008 (DEEP-C)

Vorticity structure and evolution in a transverse jet with new algorithms for scalable particle simulation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 188-200).Transverse jets arise in many applications, including propulsion, effluent dispersion, oil field flows, V/STOL aerodynamics, and drug delivery. Furthermore, they exemplify flows dominated by coherent structures that cascade into smaller scales, a source of many current challenges in fluid dynamics. This study seeks a fundamental, mechanistic understanding of the relationship between the dispersion of jet fluid and the underlying vortical structures of the transverse jet-and of how to develop actuation that optimally manipulates their dynamics to affect mixing. We develop a massively parallel 3-D vortex simulation of a high-momentum transverse jet at large Reynolds number, featuring a discrete filament representation of the vorticity field with local mesh refinement to capture stretching and folding and hair-pin removal to regularize the formation of small scales. A novel formulation of the vorticity flux boundary conditions rigorously accounts for the interaction of channel vorticity with the jet boundary layer. This formulation yields analytical expressions for vortex lines in near field of the jet and suggests effective modes of unsteady actuation at the nozzle. The present computational approach requires hierarchical N-body methods for velocity evaluation at each timestep, as direct summation is prohibitively expensive. We introduce new clustering algorithms for parallel domain decomposition of N-body interactions and demonstrate the optimality of the resulting cluster geometries. We also develop compatible techniques for dynamic load balancing, including adaptive scaling of cluster metrics and adaptive redistribution of their centroids. These tools extend to parallel hierarchical simulation of N-body problems in gravitational astrophysics,(cont.) molecular dynamics, and other fields. Simulations reveal the mechanisms by which vortical structures evolve; previous computational and experimental investigations of these processes have been incomplete at best, limited to low Reynolds numbers, transient early-stage dynamics, or Eulerian diagnostics of essentially Lagrangian phenomena. Transformation of the cylindrical shear layer emanating from the nozzle, initially dominated by azimuthal vorticity, begins with axial elongation of its lee side to form sections of counter-rotating vorticity aligned with the jet trajectory. Periodic rollup of the shear layer accompanies this deformation, creating arcs carrying azimuthal vorticity of alternating signs, curved toward the windward side of the jet. Following the pronounced bending of the trajectory into the crossflow, we observe a catastrophic breakdown of these sparse periodic structures into a dense distribution of smaller scales, with an attendant complexity of tangled vortex filaments. Nonetheless, spatial filtering of this region reveals the persistence of counter-rotating streamwise vorticity. We further characterize the flow by calculating maximum direct Lyapunov exponents of particle trajectories, identifying repelling material surfaces that organize finite-time mixing.by Youssef Mohamed Marzouk.Ph.D

The effect of flow and mixture inhomogeneity on the dynamics of strained flames

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (leaves 76-80).by Youssef Mohamed Marzouk.S.M

2-[2-(4-Methoxyphenyl)-4,5-diphenyl-1 H

In the title compound, C(24)H(22)N(2)O(2), the central imidazole ring makes dihedral angles of 49.45 (8), 88.94 (9) and 19.43 (8)° with the benzene ring and the two phenyl rings, respectively. The dihedral angle between the phenyl rings is 77.86 (9)°, and they form dihedral angles of 49.06 (9) and 67.31 (8)° with the benzene ring. In the crystal, mol­ecules are linked by O—H⋯N hydrogen bonds, forming chains along the b axis. These chains are connected by C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (100). In addition, C—H⋯π inter­actions are also observed. The terminal C and O atoms of the ethanol group are disordered over two sets of sites with an occupancy ratio of 0.801 (5):0.199 (5)

PROSPECTIVE EFFECT OF RED ALGAE, ACTINOTRICHIA FRAGILIS, AGAINST SOME OSTEOARTHRITIS AETIOLOGY

Background: Osteoarthritis (OA) is a progressive disease characterized by joints pain and articular cartilage destruction. Most of the current treatment strategies for OA are effective for symptoms relief but are accompanied with adverse side effect. Thus, the present investigation aims to evaluate the potential influence of red algae, Actinotrichia fragilis, in the dry powder form (AFP) or gel form (AFG) on some relevant factors of OA progression as well as assess its safety through in vitro and in vivo experiments. Materials and Methods: In vitro, AFP was analyzed for its chemical constituents screening, amino acid, proteinase inhibitory activity, HRBC membrane stabilization activity, free radical scavenging activity, total antioxidant potency, nitric oxide radical scavenging power. In vivo, Organization for Economic Co-operation and Development (OECD) toxicity test was performed to test the safety of AFP on rats. Results: The present findings revealed that AFP and AFG can be considered as inflammatory-proteinase-oxidant inhibitor and considered to be safe according to the OECD guideline. Conclusion: AFP and AFG may have the potency to become the therapeutic candidate for OA disease as it prevents the key causes of OA initiation

Screening for hypertension among adults: community outreach in Cairo, Egypt

Background: Studies have shown alarming levels of hypertension among adults in the Middle East. The aim of our study is to measure the prevalence rate of hypertension among adults in Cairo (Egypt), identify possible risk factors for the development of hypertension and assess the rates of undiagnosed and uncontrolled hypertension. Methods: Cluster sampling was utilized and the fieldwork was conducted by 12 teams; each team consisted of a house officer, community worker and senior epidemiologist. A formulated questionnaire that addresses risk factors for hypertension was filled by all participants. Also, weight and height measurements were done to calculate the body mass index. Blood pressure measurement was done by calibrated sphygmomanometers. Blood pressure measurement was done twice, and a mean recording was calculated. A case which recorded both systolic blood pressure of ≥140 and diastolic blood pressure of ≥90 was considered hypertensive. Results: The study included 774 adult residents of Al-Waily District (Western Zone of Cairo) in late 2011 and early 2012. The mean age of the study participants was 46.5 (SD 17.9) years. Female subjects constituted 67.1% of the studied sample. The prevalence rate of hypertension in our study was 16.5% (95% confidence interval (CI): 13.9-19.3). The rate of hypertension was higher among females and three times higher among obese compared with normal or overweight adults. The prevalence of undiagnosed hypertension was 11% (95% CI: 8.4-13.9), and uncontrolled hypertension was 30% (95% CI: 24.2-37). Conclusions: Community outreach campaigns should be conducted regularly in the future for early detection of hypertension cases and proper health education about hypertension and its dangerous consequences

Comparison between the Accuracy of Endoanal Ultrasonography and Body Coil MRI in Preoperative Assessment of Internal Opening of Perianal Fistula Complex

Abstract Background and Aim: Surgery for anal fistula is a commonly performed practice. Integral part of fistula surgery is identification of the internal opening if high recurrence rate is to be diminished. In this study, accuracy of endoanal ultrasound versus body coil M.R.I in detection of the internal fistula opening was evaluated by comparing both modalities with the intra operative findings as a standard reference

Injection Drug Use Is a Risk Factor for HCV Infection in Urban Egypt

OBJECTIVE: To identify current risk factors for hepatitis C virus (HCV) transmission in Greater Cairo. DESIGN AND SETTING: A 1:1 matched case-control study was conducted comparing incident acute symptomatic hepatitis C patients in two "fever" hospitals of Greater Cairo with two control groups: household members of the cases and acute hepatitis A patients diagnosed at the same hospitals. Controls were matched on the same age and sex to cases and were all anti-HCV antibody negative. Iatrogenic, community and household exposures to HCV in the one to six months before symptoms onset for cases, and date of interview for controls, were exhaustively assessed. RESULTS: From 2002 to 2007, 94 definite acute symptomatic HCV cases and 188 controls were enrolled in the study. In multivariate analysis, intravenous injections (OR = 5.0; 95% CI = 1.2-20.2), medical stitches (OR = 4.2; 95% CI = 1.6-11.3), injection drug use (IDU) (OR = 7.9; 95% CI = 1.4-43.5), recent marriage (OR = 3.3; 95% CI = 1.1-9.9) and illiteracy (OR = 3.9; 95% CI = 1.8-8.5) were independently associated with an increased HCV risk. CONCLUSION: In urban Cairo, invasive health care procedures remain a source of HCV transmission and IDU is an emerging risk factor. Strict application of standard precautions during health care is a priority. Implementation of comprehensive infection prevention programs for IDU should be considered