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The 8-node iso-parametric thin shell element was employed in the study of stress concentrations in the welded tubular “K” joint. Element equilibrium equations were derived using isoparametric formulation based on thin shell theory. After assembly, the resulting system equations were solved using existing fortran programs. Numerical experiments were conducted to isolate and locate ideal gap (positions) for the two braces of the “K” joint. The nominal stresses were calculated from which stress concentration factors were obtained. The resulting stress concentration factors were presented both as tables and as figures. A good agreement between our solutions and those for model joints in the literature is good and acceptable. It was found that the wider apart the brace spacing is, the weaker the strength of the joint. It was also found that the best location for the braces occurs when the stress level changes sign either from positive to negative or vice versa at a critical sampling point.
Calcified rock-forming marine filamented benthic micro- and macrophytes of Dzhelindia Kolosov, 1970 (Figure 1(а)) and Chaptchaica Kolosov, 1975 (Figure 1(b)) genera, thrived in Neoproterozoic (1000-541 million years ago) Siberia together with cyanobacteria. Their belonging to Rhodophyta is well-grounded. These and other Neoproterozoic rodofits, as well as Epiphyton Bornemann 1886 (Figure 1(c)) and other Early Cambrian (541-513 million years ago) benthic algae, oxygenating floor of epicontinental sea basin, formed conditions, favorable for the animals. In combination with other biotic, and such abiotic factors as: equatorial position and tectonic feature of Siberian platform; volcanism; transgression of the sea; diversity of ecologic niches, these conditions were prerequisites of skeleton and shell acquisition by Early Cambrian animals, and as a consequence, accelerated morphologic evolution, increased diversity of taxons of different groups of animals.
The gross alpha (α)
and beta (β) activities and trace heavy elemental concentrations have
been determined in Single Super Phosphate
(SSP) and Nitrogen Phosphorous Potassium (NPK) fertilizers samples used
for agricultural purposes in Nigeria. Cultivated farm soil samples from two
regions (north and south) in the country and samples of phosphate rocks were
also analyzed for gross α and β radioactivity and elemental
concentrations. The beta activity concentration in the NPK (15-15-15)
fertilizers was found to vary from 2410.0 ± 80.0 Bq·kg–1 to 4560 ± 140.0 Bq·kg–1, between 1340.0 ± 70.0 Bq·kg–1 and 1440.0 ± 70.0 Bq
In this paper, we
deal with the uniqueness problems on entire and meromorphic functions con- cerning
differential polynomials that share fixed-points. Moreover, we generalise and
improve some results of Weichuan Lin, Hongxun Yi, Meng Chao, C. Y. Fang, M. L.
Fang and Junfeng xu.
Two very important
factors which determine the effectiveness of a pump are its volumetric and
power efficiencies. Yin and Ghoneim constructed a prototype of a Flexible-Matrix-Composite
(FMC) body pump with a very high volumetric efficiency or pumping potential
(the relative volume reduction due to a relative input stroke). The high
volumetric efficiency is attributed to the geometry of the pump’s structure
(hyperboloid) as well as the high negative effective Poisson’s ratio of the
flexible-matrix-composite (carbon/polyurethane) laminate adopted for the body
of the pump. However, the power efficiency of the pump was not evaluated. It is
the objective of the current paper to obtain an estimate of the power
efficiency of the pump. The viscoelastic properties of the 3-layer FMC
(carbon/polyurethane) laminate are evaluated experimentally using the Dynamic
Mechanical Analyzer (DMA) as well as analytically by applying the correspondence
principle together with the micro-mechanics approach. In order to obtain an
estimate of the power efficiency of the FMC body pump, the axial and shear loss
factors of a laminated infinitely long cylindrical tube as functions of β and θ fiber orientation angles are determined employing the Adam and
Bacon approach. The analysis engenders high loss factors (greater than 0.4),
which suggests that the power efficiency of the proposed pump using the 3-layer
carbon/polyurethane laminate may be low.
The flow of viscous incompressible fluid through a tube is considered. The similarity transformation is used to reduce the governing equations into nonlinear ordinary differential equation. The solution procedure includes application of long series analysis with polynomial coefficients. The series representing physical parameters ( ) reveal qualitative features which are comparable to pure numerical results. The analysis enables in extending region of validity. A complete description of the solutions is presented.