Isogeometric analysis for functionally graded microplates based on modified couple stress theory

Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture the size-dependent effects within the microplates. Meanwhile, the quasi-3D theory which is constructed from a novel seventh-order shear deformation refined plate theory with four unknowns is able to consider both shear deformations and thickness stretching effect without requiring shear correction factors. The NURBS-based isogeometric analysis is integrated to exactly describe the geometry and approximately calculate the unknown fields with higher-order derivative and continuity requirements. The convergence and verification show the validity and efficiency of this proposed computational approach in comparison with those existing in the literature. It is further applied to study the static bending, free vibration and buckling responses of rectangular and circular functionally graded microplates with various types of boundary conditions. A number of investigations are also conducted to illustrate the effects of the material length scale, material index, and length-to-thickness ratios on the responses of the microplates.Comment: 57 pages, 14 figures, 18 table

A profiling analysis of contributions of cigarette smoking, dietary calcium intakes, and physical activity to fragility fracture in the elderly

Fragility fracture and bone mineral density (BMD) are influenced by common and modifiable lifestyle factors. In this study, we sought to define the contribution of lifestyle factors to fracture risk by using a profiling approach. The study involved 1683 women and 1010 men (50+ years old, followed up for up to 20 years). The incidence of new fractures was ascertained by X-ray reports. A “lifestyle risk score” (LRS) was derived as the weighted sum of effects of dietary calcium intake, physical activity index, and cigarette smoking. Each individual had a unique LRS, with higher scores being associated with a healthier lifestyle. Baseline values of lifestyle factors were assessed. In either men or women, individuals with a fracture had a significantly lower age-adjusted LRS than those without a fracture. In men, each unit lower in LRS was associated with a 66% increase in the risk of total fracture (non-adjusted hazard ratio [HR] 1.66; 95% CI, 1.26 to 2.20) and still significant after adjusting for age, weight or BMD. However, in women, the association was uncertain (HR 1.30; 95% CI, 1.11 to 1.53). These data suggest that unhealthy lifestyle habits are associated with an increased risk of fracture in men, but not in women, and that the association is mediated by BMD

Scalar sextet in the 331 model with right-handed neutrinos

A Higgs sextet is introduced in order to generate Dirac and Majorana neutrino masses in the 331 model with right-handed neutrinos. As will be seen, the present sextet introduction leads to a rich neutrino mass structure. The smallness of neutrino masses can be achieved via, for example, a seesaw limit. The fact that the masses of the charged leptons are not effected by their new Yukawa couplings to the sextet is convenient for generating small neutrino masses.Comment: RevTeX4, 5 pages, no figure. To appear in Phys. Rev. D. Misprints removed (v.2

Development of freshwater prawn (Macrobrachium rosenbergii) seed production and culture technology in the Mekong Delta Region of Vietnam: A review of the JIRCAS Project at Cantho University.

The Mekong Delta of Vietnam is a region rich in aquatic resources having high potential for aquaculture development. Inland aquaculture in the Mekong Delta has greatly increased since the last decade. Fish culture carried out in combination with other agricultural activities such as animal husbandry and rice cultivation, and intensive aquaculture in ponds and cages have been the dominant forms of fish production. However, the giant freshwater prawn, Macrobrachium rosenbergii, has recently become a species of economic significance and the target of aquaculture activity in the Mekong Delta. M. rosenbergii is cultured throughout the region in the rice fields, ponds, orchard gardens and in pens along river banks. The major constraints in this industry are seed supply and culture techniques, becoming the major obstacles for the further development of the culture of this species. In a collaborative research project implemented between the Japan International Research Center for Agricultural Sciences (JIRCAS) and Cantho University (CTU) since 1994, studies have been carried out on various aspects relating to the establishment of M. rosenbergii seed production and culture technology. The project is now in the middle of its second phase and has generated a great deal of scientific and practical information. This paper presents an overview of the achievements of this project

Seismic Interpretation of the Nam Con Son Basin and Its Implication for the Tectonic Evolution

DOI:10.17014/ijog.3.2.127-137The Nam Con Son Basin covering an area of circa 110,000 km2 is characterized by complex tectonic settings of the basin which has not fully been understood. Multiple faults allowed favourable migration passageways for hydrocarbons to go in and out of traps. Despite a large amount of newly acquired seismic and well data there is no significant update on the tectonic evolution and history of the basin development. In this study, the vast amount of seismic and well data were integrated and reinterpreted to define the key structural events in the Nam Con Son Basin. The results show that the basin has undergone two extentional phases. The first N - S extensional phase terminated at around 30 M.a. forming E - W trending grabens which are complicated by multiple half grabens filled by Lower Oligocene sediments. These grabens were reactivated during the second NW - SE extension (Middle Miocene), that resulted from the progressive propagation of NE-SW listric fault from the middle part of the grabens to the margins, and the large scale building up of roll-over structure. Further to the SW, the faults of the second extentional phase turn to NNE-SSW and ultimately N - S in the SW edge of the basin. Most of the fault systems were inactive by Upper Miocene except for the N - S fault system which is still active until recent time

The Higgs Sector of the Minimal 3 3 1 Model Revisited

The mass spectrum and the eigenstates of the Higgs sector of the minimal 3 3 1 model are revisited in detail. There are discrepancies between our results and previous results by another author.Comment: 20 pages, latex, two figures. One note and one reference are adde