A phase adjuster (PA) is proposed to improve the cooling effect of a loop-tube-type thermoacoustic cooling system. A PA is a device for accelerating the particle velocity. The PA is embedded in the loop tube and narrows the cross-sectional area of the part of the loop tube. The PA creates a strong boundary condition in which the particle velocity is accelerated. It is confirmed that the phases of the sound pressure and particle velocity are adjusted so that the sound generated in the loop tube is resonated with the total tube length at one-wavelength resonance. This results in a great improvement in the cooling effect of the thermoacoustic cooling system.

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This paper presents the application of anAutomatic Phase Balancing Device (APBD) to reduce current unbalance in low voltage distribution networks. The proposed algorithm allowsus to calculate the unbalanced level and to conduct the automatic phase balancing device during load variations. This device was then applied to a low voltage feeder of Cau Giay district (Viet Nam). Results show that the unbalanced current is always maintained lessthan 15 %.

In this study, ZnO-doped carbon aerogel is synthesized from cellulose in coconut peat with sodium alginate as a binder via both freeze-drying and pyrolysis processes. Of those, zinc nitrate is used as not only a crosslinking agent to form gel but also a precursor source to dope ZnO in the carbon aerogel matrix. The

The article proposes the use of a geodetic coordinate frame suitable for the reference plan geodetic networks of Vietnam used in engineering surveys. This framework minimizes distortion in horizontal spacing when going from ellipsoid to plane. In the course of the work, the parameters of the coordinate system and the height of the level surface were selected using the Universal Transverse Mercator (UTM). The equations used for the calculations are determined based on theoretical analysis and are easily applied in surveying.