Study of Nd203-CuO-P205 glass system by elastic properties

Longitudinal and shear ultrasonic velocities were measured in different compositions of the glass system Nd203(x)CuO(35-x)P205(65) at temperature range between 270 K and 323 K. From the transit time data and density, we found that all the elastic properties for these glasses decrease as the Nd203 content increase, which indicates a weakening ofthe binding energy in the network

Organs in Orthodox Worship: Debate and Identity

Conceptions of Orthodox identity typically involve three important topics—dispute, validation, and diversity. This essay examines the use of instrumental music, specifically organs, within Orthodox parishes, a phenomenon localized mostly to churches of the Greek Orthodox Archdiocese of America, and the means by which debates around instrumental use form conceptions of Orthodox identity. After examining arguments for and against the use of instruments within worship, the essay concludes with a call for a greater emphasis to be placed on diversity within Orthodox liturgical praxis and, to a larger degree, thought

Performance of a hydrogen burner to simulate air entering scramjet combustors

Tests were conducted to determine the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions. The test gas simulates air in that it duplicates the total temperature, total pressure, and the volume fraction of oxygen of air at flight conditions. The main objective of the tests was to determine the performance of the burner as a function of the effective exhaust port area. The conclusions were: (1) pressure oscillations of the chugging type were reduced in amplitude to plus or minus 2 percent of the mean pressure level by proper sizing of hydrogen, oxygen, and air injector flow areas; (2) combustion efficiency remained essentially constant as the exhaust port area was increased by a factor of 3.4; (3) the mean total temperature determined from integrating the exit radial gas property profiles was within plus or minus 5 percent of the theoretical bulk total temperature; (4) the measured exit total temperature profile had a local peak temperature more than 30 percent greater than the theoretical bulk total temperature; and (5) measured heat transfer to the burner liner was 75 percent of that predicted by theory based on a flat radial temperature profile

The effect of initial flow nonuniformity on second-stage fuel injection and combustion in a supersonic duct

The effects of flow nonuniformity on second-stage hydrogen fuel injection and combustion in supersonic flow were evaluated. The first case, second-stage fuel injection into a uniform duct flow, produced data indicating that fuel mixing is considerably slower than estimates based on an empirical mixing correlation. The second-case, two-stage fuel injection (or second-stage fuel injection into a nonuniform duct flow), produced a large interaction between stages with extensive flow separation. For this case the measured wall pressure, heat transfer, and amount of reaction at the duct exit were significantly greater than estimates based on the mixing correlation. Substantially more second-stage fuel burned in the second case than in the first case. Overall effects of unmixedness/chemical kinetics were found not to be significant at the exit for stoichiometric fuel injection

LEAD AND CADMIUM REMOVAL FROM AQUEOUS SOLUTION USING WASTE MATERIAL (MICROWAVE INCINERATED RICE HUSK ASH)

Presence of heavy metals in aquatic systems has become a serious problem. Heavy metals such Cadmium (Cd) and Lead (Pb) are mostly resulted from industrial activities and adverse effects on environment as well as human health. As a result, there has been a great deal of attention given to new technologies for removal of heavy metal ions from contaminated waters. Commonly used treatment technologies were mostly effective, except for their high operational cost. Thus, this study proposed Microwave Incinerated Rice Husk Ash (MIRRA), locally available agricultural waste for the removal of Pb (II) and Cd (II) from synthetic wastewater by batch adsorption process. Adsorption involves separation of a substance from one phase accompanied by its accumulation or concentration at the surface of another. Influences of pH, initial metal concentration, contact time and absorbent dosage on the removal efficiency of those metals from aqueous solution were studied. pH 3.0 and 4.0 were found to be optimum condition for maximum adsorption of Pb (II) and Cd (II) ions from aqueous solution. The removal efficiency of both metals correlated with the contact time between adsorbent and adsorbate, initial metal concentration as well as adsorbent dosage. Adsorption of Pb (II) and Cd (IT) were reached equilibrium after 60 and 120 minutes respectively; with both found to be better fitted with pseudo second order kinetic model. The maximum removal percentage of Pb (II) and Cd (II) were achieved at an adsorbent loading weight of 400 mg and 200 mg correspondingly. The equilibrium adsorption capacity of adsorbent used for Pb (II) and Cd (II) was calculated to be Langmuir and Freundlich respectively. The experimental data were found to fit the Langmuir isotherm for Pb (II) (R2 = 0.9991) and Freundlich isothetm for Cd (II) (R2 = 0.7951 )