On the rate of convergence in periodic homogenization of scalar first-order ordinary differential equations

In this paper, we study the rate of convergence in periodic homogenization of scalar ordinary differential equations. We provide a quantitative error estimate between the solutions of a first-order ordinary differential equation with rapidly oscillating coefficients and the limiting homogenized solution. As an application of our result, we obtain an error estimate for the solution of some particular linear transport equations

The top quark electric dipole moment in an MSSM extension with vector like multiplets

The electric dipole moment (EDM) of the top quark is calculated in a model with a vector like multiplet which mixes with the third generation in an extension of the MSSM. Such mixings allow for new CP violating phases. Including these new CP phases, the EDM of the top in this class of models is computed. The top EDM arises from loops involving the exchange of the W, the Z as well as from the exchange involving the charginos, the neutralinos, the gluino, and the vector like multiplet and their superpartners. The analysis of the EDM of the top is more complicated than for the light quarks because the mass of the external fermion, in this case the top quark mass cannot be ignored relative to the masses inside the loops. A numerical analysis is presented and it is shown that the top EDM could be close to $10^{-19} ecm$ consistent with the current limits on the EDM of the electron, the neutron and on atomic EDMs. A top EDM of size $10^{-19}ecm$ could be accessible in collider experiments such as the ILC.Comment: 21 pages and 5 figues. Accepted for publication in Physical Review

The Chromoelectric Dipole Moment of the Top Quark in Models with Vector Like Multiplets

The chromoelectric dipole moment of the top quark is calculated in a model with a vector like multiplet which mixes with the third generation in an extension of the MSSM. Such mixings allow for new CP violating phases. Including these new CP phases, the chromoelectric dipole moment that generates an electric dipole of the top in this class of models is computed. The top chromoelectric dipole moment operator arises from loops involving the exchange of the W, the Z as well as from the exchange involving the charginos, the neutralinos, the gluino, and the vector like multiplet and their superpartners. The analysis of the chromoelectric dipole moment operator of the top is more complicated than for the light quarks because the mass of the external fermion, in this case the top quark mass, cannot be ignored relative to the masses inside the loops. A numerical analysis is presented and it is shown that the contribution to the top EDM could lie in the range ($10^{-19}-10^{-18})$ ecm consistent with the current limits on the EDM of the electron, the neutron and on atomic EDMs. A top EDM of size $(10^{-19}-10^{-18})$ ecm could be accessible in collider experiments such as at the LHC and at the ILC.Comment: 17 pages, 6 figures. Accepted for publication in Phys. Rev.

Extraction, Characterization and Determination of Physicochemical Properties of Biodiesel obtained from Desert Date (Balanites aegyptiaca) Seed Oil

Biodiesel is a domestically produced, clean-burning, renewable substitute for petroleum diesel. Using biodiesel as a vehicle fuel increases energy security, improves air quality and the environment, and provides safety benefits. . This study extracted, characterized and determined the physicochemical properties of biodiesel produced from Desert date (B. aegyptiaca) seed oil using Soxhlet extraction method with n-hexane as the extraction solvent. The oil obtained was characterized using FTIR and GC-MS analyses and its physicochemical properties determined. The oil obtained was subsequently transesterified using methanol and KOH catalyst. The obtained biodiesel was characterized and its physicochemical properties determined. The result showed that B. aegyptiaca seed oil had density of 0.9 g/cm3, viscosity of 6 cSt at 40 0C and viscosity of 2.5 cSt at 100 0C. The cloud and pour points of the oil was 21 and 9 0C respectively. The oil comprised of eleven fatty acids; predominantly linoleic acid (21.88 %), vaccenic acid (13.90 %) and palmitic acid (10.96 %). The biodiesel had density of 0.88 g/cm3, kinematic viscosity of 4.2 cSt, cloud and pour points of 16 0C and 7 0C respectively. The biodiesel also had free fatty acid (FFA) of 0.79 %, iodine value of 42 mgI2/100g and saponification value of 176. The biodiesel primarily consisted of 9,12-Octadecadienoic acid methyl ester (45.46 %), Hexadecanoic acid methyl ester (20.12 %), Butyl-9,12-Octadecadienoate (12.43 %) and Heptadecanoic acid-16-methyl ester (10.43 %). The properties obtained for the biodiesel were comparable to those of biodiesels reported in literature and thus, shows remarkable potentials to be used as substitute to fossil-based diesel fuel

Production of Biolubricants from Balanites aegyptiaca Seed Oil via Epoxidation and Double Transesterification Techniques

In this study, Balanites aegyptiaca seed oil was extracted from the ground seed using the Soxhlet extraction method with n-hexane as the extraction solvent to produce two biolubricants; one via epoxidation to produce Balanites aegyptiaca Lubricant (BAB-E) and the other via transesterification with trimethylolpropane to produce Balanites aegyptiaca Lubricant (BAB-T). Both biolubricants were characterized using Fourier Transform Infrared Spectrometry. The physicochemical properties, lubricity and thermal properties of the produced biolubricants were determined. Results showed that the biolubricants had wavelengths of 3008.0 cm-1 associated with C-H stretching, 2922.8 cm-1 to -OH (acid), 1740.7 cm-1 to C=O, 1488.8 cm-1 to C=C stretching, 1364.2 cm-1 to NO2, 1237.6 cm-1 to C-O, 1159.2 cm-1 to C-C and 723.1 cm-1 to C-H bending. BAB-T had viscosities of 58.29 and 10.36 cSt at 40 and 100 OC respectively while those of BAB-E were 54.37 and 9.56 cSt. They had viscosity index of 168 and 161, and pour points of -9 and -8 respectively. These values were observed to be within acceptable range. BAB-T had coefficient of friction of 0.094 ± 0.014 while that of BAB-E was 0.080 ± 0.010 respectively. The biolubricants were observed to have thermal stability and showed properties similar to those of lubricants and show remarkable potentials to be used as alternatives to fossil-based lubricants

Intensive shrimp Penaeus semisulcatus Dee Haan, culture in the Arabian Gulf during the summer

P. semisulcatus juveniles (average weight 9.7g) from Manifa Lagoon on the Arabian Gulf were randomly stocked in tanks (0.8m3) at three stocking density levels (25, 50 and 75 shrimp/m3) in four replicates. The tanks were put together in a flow-through system and were covered with plastic nets. Water flow rates were 1, 2, and 3 litres/min for densities 25, 50 and 75 shrimp/m3, respectively, Filtered aerated seawater (30± 3 °C) was utilized. Fresh water was mixed with the seawater to keep water salinity down to 39%o. The whole system was shaded to reduce water temperature from the direct sun light. Shrimps were fed during the night for six weeks experimental period. No mortality occurred throughout the experimental period. Growth rates were similar in the three stocking densities, under the experimental conditions. Future studies are needed to determine the maximum sustainable stocking densities

Effects of CP Violation on Event Rates in the Direct Detection of Dark Matter

A full analytic analysis of the effects of CP violating phases on the event rates in the direct detection of dark matter in the scattering of neutralinos from nuclear targets is given. The analysis includes CP violating phases in softly broken supersymmetry in the framework of the minimal supersymmetric standard model (MSSM) when generational mixings are ignored. A numerical analysis shows that large CP violating phases including the constraints from the experimental limits on the neutron and the electron electric dipole moment (EDM) can produce substantial effects on the event rates in dark matter detectors.Comment: 17 pages, LaTex, including 2 figures; revised version to appear in the Physical Review

A Predictive Structural Model of Standards-Based School Evaluation on Student Outcome

The current study examined the relationship between school leadership, school environment, teaching and learning strategies, and students’ performance on national assessment in math and science. In addition, it examined the mediating role of teaching and learning strategies in its relation to school leadership, school environment, and students’ performance in math and science as well. Study data was utilized from two datasets. First, the School Evaluation Standards scale (SES), which includes three subscales: school leadership, school environment, and teaching and learning strategies was utilized from a total of 711 schools that were randomly chosen from Saudi Arabia. Second, these school average scores in national assessment of math and science were collected. The finding revealed that there were direct and indirect effects of school leadership, school environment, teaching and learning strategies on students’ performance in math and science. Furthermore, teaching and learning strategies played as mediator between school leadership and school environment and students performance in math and science. The results of the research provided insights on how school evaluation standards (SES) affect academic performance and learning outcomes. Educational policy makers can benefit from the results of this study by evaluating school performance assessment standards and the level of practices to gauge the degree of application in real world practices and determine the room for improvements

The Pulsed Spectra of Two Extraordinary Pulsars

We report on X-ray monitoring of two isolated pulsars within the same RXTE field of view. PSR J1811-1925 in the young supernova remnant G11.2-0.3 has a nearly sinusoidal pulse profile with a hard pulsed spectrum (photon index \~1.2). The pulsar is a highly efficient (~ 1% of spin-down energy) emitter of 2-50 keV pulsed X-rays despite having a fairly typical B ~ 2e12 G magnetic field. PSR J1809-1943/XTE J1810-197 is a newly discovered slow (P=5.54 s), apparently isolated X-ray pulsar which increased in flux by a factor of ~100 in 2003 January. Nine months of monitoring observations have shown a decrease in pulsed flux of ~ 30% without a significant change in its apparently thermal spectrum (kT ~0.7 keV) or pulse profile. During this time, the spin-down torque has fluctuated by a factor of ~ 2. Both the torque and the flux have remained steady for the last 3 months, at levels consistent with a magnetar interpretation.Comment: 3 pages, 4 figures, to appear in the Proceedings of X-ray Timing 2003: Rossi and Beyond, ed. P. Kaaret, F.K. Lamb, & J.H. Swank held in Cambridge, MA, Nov. 3-5, 200

Gaugino CP phases and EDMs in the extended gauge mediation SUSY breaking

We study phenomenological aspects of the soft supersymmetry breaking parameters in a model with the extended gauge mediation supersymmetry breaking. In this model gaugino masses can be non-universal and as its result physical CP-phases remain in the gaugino sector even after the R-transformation. These phases contribute to the electric dipole moment (EDM) of an electron and a neutron. We show that their experimental bounds can be satisfied even for the situation such that there exist the order one CP-phases and the masses of superpartners are of the order of 100 GeV.Comment: LaTeX, 26 pages, 6 figure