Search

A long standing shortfall in the predicted L-mode edge energy transport by reduced quasi-linear models of gyrokinetic turbulent transport has been resolved. The improved model TGLF-SAT2 has higher fidelity to gyrokinetic simulations of the electron-scale contribution to the electron energy transport and the ion-scale flux surface shape dependence of energy transport. The success of TGLF-SAT2 in predicting the L-mode and Ohmic edge profiles is critical to whole pulse simulation and opens the door to prediction of the H-mode power threshold.

A field trial was conducted at Esna, Luxor Governorate, Egypt during 2012/2013 and 2013/2014 seasons to study the effect of mineral NPK and organic fertilization on growth, yield, essential oil and herb N, P and K % of Coriandrum sativum, L. plants. The obtained results revealed that all studied characters of growth, yield, essential oil and herb % of NPK were significantly augmented due to the use of both low and high NPK fertilization rates with the high one giving the highest values. Concerning organic fertilization, the different growth traits (plant height, stem diameter and herb dry weight), yield and yield component characters (number of umbels/plant and fruit yield per plant and per fed), essential oil parameters (percent and yield per plant and per fed) and NPK % in the herb were gradually increased parallel to the gradual increase in compost level. The combined treatment between the low NPK rate (50 g kristalon/10.8 m2 plot)and medium compost level (10 ton/fed) resulted in better fruit and essential oil yield than that obtained from the high NPK rate. So, the possibility of substituting one half of the mineral NPK dose by the medium compost level is justified.

Drillstring and down-hole tool failure usually results from failing to control one or more of the vibration mechanisms. The solution starts with the ability to measure different modes of vibration, hence identifying different vibration mechanisms. Lateral, torsion and axial are vibration modes that take place when drill pipes run into problems downhole. Due to the three modes of vibration mechanisms such as bit bounce, stick-slip, lateral shocks, bit and bottom hole assembly (BHA) whirl, parametric and torsional resonance occur. Understanding the causes of the destructive loads is the main step towards developing approaches to prevent or reduce their effects, hence improving drilling performance. Vibration modes and mechanisms lead to failure of the drill pipes, BHA and drill bits. Drill pipes fatigue failure is very common due to capability of producing all vibration modes and mechanisms. Drill pipe and downhole tool assembly failure usually result from failing to have power over one or more of these vibration mechanisms. A novel in house experimental setup has been developed to mimic downhole axial, lateral and torsional vibration modes and mechanisms in drilling operations. In this paper, we focus on the design and construction of the testing facility. A number of tests were conducted to validate the capability and performance of the test setup. Drill pipe fatigue failure due to lateral cyclic stresses induced in the drill pipe has also been investigated and presented in this paper. The results show that operating on a rotation speed higher than 90% of the drillstring critical speed leads to yielding in the drillstring.

Positron annihilation lifetime spectroscopy (PALS) is used to investigate polycrystalline substituted Li-ferrite samples. The dray ceramic technique was used to prepare all investigated samples. The variation of positron annihilation parameters I1%, I2%, τ1, and τ2 has been demonstrated with porosity and the initial permeability against the ionic radii of substituted ions for Li ferrite. The grain size (G.S.) increased with increasing the ionic radii of the substituted ions for Li-ferrite. The correlation between I2 and τ2 has opposite behavior with the ionic radii of the substituted ions. Whereas the correlation between I1 and τ1; has nearly the same behavior with the ionic radii of the substituted ions except for V and Gd samples. There is mostly a direct correlation between the electrical resistivity and I2 values except for Sm sample with increasing the ionic radii of substituted ions.