Potential effect of using ultrasonic irradiation to reduce concentration of COD in Palm Oil Mill Effluent (POME)

Many researchers have attempted in the past to look at the possibility of using ultrasonic irradiation or sonication in degrading organic compounds in aqueous wastewater. Ultrasonic irradiation was found to be a safe, clean and effective method for deterioration of specific organic compounds. Ultrasonic irradiation can be used as a stand-alone process, or can be integrated with other treatment methods. However, very limited study focuses on the application of ultrasonic irradiation for treating industrial wastewater; therefore, it is considered as a new research. When water is exposed to ultrasonic irradiation,+H and -OH radicals are produced; the latter is a strong oxidizing agent which can degrade organic pollutants. This study uses raw Palm Oil Mill Effluent (POME) as a test media to investigate the effectiveness of ultrasonic irradiation in reducing organic compounds based on the Chemical Oxygen Demand (COD) concentration at selected operating conditions, namely power density of ultrasonic probe and addition of catalysts. Results showed percentage reduction of COD was highest at power density 29W/L than power density 55W/L. Power density 29W/L of ultrasonic probe chose to combine with catalysts. Application of ultrasonic irradiation with presence of the catalysts CuSO4 and FeSO4, increased the percentage of COD reduction, but FeSO4 gave a better result. The highest percentage reduction of COD of raw POME is around 30% after ultrasonic irradiation process combined with the catalyst FeSO4

Acoustic Properties of Lanthanum-Samarium Phosphate Glasses

From measurements of changes in transit time of 10 MHz of ultrasonic waves as a function of temperature and hydrostatic pressure, the acoustic properties of (La203)x(Sm203)y(P20,,) (l-x-y) glasses with compositions near to that corresponding to the metaphosphate have been determined. For each glass, the second order elastic stiffness tensor components Cij ' (SOEC) continue to increase down to 10 Kin a manner consistent with phonon interactions with tVi'Qlevel systems. Measurements of the effects of hydrostatic pressure on the ultrasonic wave velocities have been used to determine the hydrostatic pressure derivatives (dCij/dP) T,P=O of the SOEC and (dBo'/ dP) T,P=O of the bulk modulus Bo at room temperature (293K). For these glasses, (dCll/dP), (dC44/dP), and (dBo / dP), are small but positive; the corresponding glasses stiffen under pressure. The elastic behaviour under pressure of these glasses lies intermediate between those of (Sm203)y(P20,,),(I_x) and (La20:1)y(P20,,) (I-x) glasses. Replacement of La3+ by Sm3+ in the temary phosphate glasses drives a slight acoustic mode softening. Possible. sources of the different effect of La:>+ and Sm3+ modifiers on the nonlinear acoustic properties of metaphosphate glasses are discussed

Penggunaan Kaedah Dinamik Ultrasonik bagi Menentukan Pemalar Kenyal Kayu Tropika

This paper reports the determination of elastic constants for 56 tropical wood species using the dynamic ultrasonic technique. Longitudinal waves (45 kHz) were used to measure the velocity in the radial (R), tangential (T) and longitudinal (L) anisotropic directions of each sample of wood. The diagonal elastic constants of each species of wood studied were estimated using the values of ultrasonic wave velocities and their mean densities via the Christoffel equations. The results show that there is a linear correlation between the elastic constants in the L, Rand T directions and density of wood. Comparison between the ultrasonic measurement and static measurement indicate that the ultrasonic measurement technique is also capable of assessing the quality of\ud tropical medium and heavy hardwood

Specific-heat Study of Low-energy Vibrational State m Vitreous Samarium Phosphates

Measurements of specific heat in the temperature range 1.5K to 30K were made for two samples of vitreous samarium phosphates. A large contribution to the specific heat, well above what is expected from acoustic phonons (in the Debye approximation), is discussed in terms of the theoretical predictions of a phonon-fracton cross-over approach. The phonon-fracton density of states used to fit the excess specific heat gives rise to model parameters with the same magnitudes as those found previously for a wide range of glasses

Effect of AgI addition on elastic properties of quaternary tellurite glass systems

A series of quaternary tellurite glasses {[(TeO2)70(B2O3)30] 90[Ag2O]10}100-z{AgI}z with z=5, 8, 10, 13 and 15 mol% were fabricated by rapid quenching technique. Pulse echo technique was employed to detect the longitudinal and shear ultrasonic velocities generated by 5 MHz transducer room temperature. Elastic properties, Poisson’s ratio, micro hardness, softening temperature and Debye temperature calculated from the measured density and ultrasonic velocity were observed to decrease monotonously with the increase of AgI content. This shows that the presence of AgI inside the glass network creates a loose packing structure of the glass network and hence reduces the rigidity and the strength of the glass system

Acoustic and thermal vibrational behavior of rare earth glasses

The ultrasonic wave velocity and the thermal expansion of the rare earth glasses have been measured as functions of temperature and pressure to test predictions of the soft potential model for the acoustic and thermal properties. The longitudinal ultrasonic wave velocities increase under pressure. The hydrostatic pressure derivative of the bulk modulus is positive: these glasses show a normal elastic response as compressed. However, the pressure derivative of the shear modulus is negative and small, indicating weak softening of shear modes under pressure. The results found are used to determine the Grüneisen parameters. This is to obtain the acoustic mode contribution to thermal expansion. After subtraction of the relaxation and anharmonic contributions, the temperature dependence of the shear wave ultrasound velocity follows a linear law as predicted by the Soft Potential Model

Study of the elastic properties of (PbO)x(P2O5)1 − x lead phosphate glass using an ultrasonic technique

Fabrication of a series of binary (PbO)x(P2O5)1−x lead phosphate glasses with various mole fractions (x = 0.1 to 0.6) was carried out using a conventional melt-quenching method. The glass density was measured by using Archimedes principle. The ultrasonic wave velocities (Vl and Vt) of the glasses were determined at room temperature by using a nondestructive test: the digital signal processing technique of the Ultrasonic Data Acquisition System (Matec 8020, Matec Instruments, USA). The experimental data for the wave velocities and densities were then used to determine the elastic properties in each series of lead phosphate glass systems: the longitudinal, shear, bulk and Young's moduli; Poisson's ratio; and the Debye temperature. Based on the results obtained, the longitudinal, shear, bulk and Young's moduli of the glasses increased with the addition of PbO content. The Poisson's ratio obtained remains almost constant, while the Debye temperature shows a continuous decrease with the addition of PbO content