The acoustic field generated by a moving point source in terms of normal modes predicts that each mode has a different Doppler shift, i.e., modal Doppler shifts, which contains the velocity information of the moving source. This paper presents a method to estimate the velocity of a distant harmonic source in a Pekeris waveguide passively based on modal Doppler shifts. Combined with the fact that the modal depth function varies slowly with frequency, a cost function is designed to realize the velocity estimation of a distant harmonic source with a single hydrophone when the bottom parameters are unknown. The effectiveness of the method is validated by simulations.

Hollow yttria partially stabilized zirconia (8 wt% Y 2 O 3 fibers have been successfully synthesized using cotton fibers as template. Cotton fibers were first immersed into a mixed solution of Zr(NO 3 4 and Y(NO 3 3 and subsequently sintered in air at a high temperature to obtain the final YPSZ fibers. The as-prepared fibers were characterized by SEM and XRD, respectively. TG-DTG and DTA were also adopted to investigate the sintering process. The results indicated that the synthesized YPSZ fibers are hollow in centre and still retain the fibrous cotton morphologies after the complete removal of the cotton body. And these hollow fibers may have good thermal insulating properties that can be used as thermal barriers at high temperatures.

Estimation of modal wavenumbers is important for inference of geoacoustic properties and data-driven matched field processing in shallow water waveguides. This paper introduces a deep neural network called combining physical informed neural network (CPINN) for modal wavenumber estimation using a vertical linear array (VLA). Note that the sound field recorded by a VLA can be expressed as a linear superposition of finite modal depth functions, and the differential equations satisfied by the modal depth functions are related to the corresponding modal wavenumbers. CPINN can estimate the modal wavenumbers by introducing the proxies of the modal depth functions and constraining them to satisfy the corresponding differential equations. The performance of the CPINN is evaluated by simulated data in a noisy shallow water environment. Numerical results show that, when compared with the previous methods, CPINN does not need to know the exact horizontal distance between the sound source and the VLA. Moreover, CPINN can estimate the modal wavenumbers at the VLA position in the case where the range segment traversed by the source, i.e., the aperture in the range direction, is smaller than the maximum modal cycle distance and in a range-dependent waveguide.

The separation process and the utility were considered simultaneously in order to reduce the cooling capacity of the propylene refrigeration system, and even to completely remove it. Two new types of heat pump distillation processes were proposed. The software Aspen Plus was used to simulate different heat pump distillation processes of ethylene and propylene to determine operating parameters and the best separation processes. The results show that the cold and hot utility would be reduced by 44.30% and 70.64% respectively when B-type and A-type heat pump distillation processes were used for ethylene and propylene separately. Furthermore, the temperature difference between hot and cold streams decreases after optimization by analyzing the T-H diagram. The energy has been more reasonably used, which proves the proposed processes are appropriate and effective.

Nanofiber nonwoven has been used in many fields due to the high surface area to volume ratio of the nanofibers and other extremely excellent properties. Nanofiber yarn, which is composed of long nanofiber with some twists for expanding nanofibers application, has been a challenging. A continuous nanofiber yarn was fabricated by a electrospinning technique with two oppositely charged spinnerets system in this work. The effect of process parameters such as applied voltage, the distance and the angle between the two spinnerets were examined in detail. The optimum parameters obtained included that the applied voltage was ±16kV, the distance and the angle between the two spinnerets were 8cm and 120o respectively. The nanofiber yarn has good potential applications in textile, medical, and biology.