This paper presents a review of methods that improve the production of volatile fatty acids (VFA) from excess sludge during the anaerobic digestion process. These methods are mainly divided into two approaches. The first approach is located in the pre-treatment methods, which change the properties of the substrates, such as thermal pre-treatment, alkaline pre-treatment, microwave pre-treatment ...

The experimental study of air movement induced by natural ventilation in greenhouses requires a system to measure the air velocity "eld. A networked, two-dimensional sonic anemometer system was developed for simultaneous measurement of the instantaneous air speed and direction at 12 locations. The system performance was tested and validated against a mass #ow controller and a commercial, three-...

Organic micro-pollutants accumulate to a certain extent in sewage sludge and are therefore ecologically relevant if the sludge is to be reused in both agriculture and landscaping applications. This paper describes the degradation of endocrine-disrupting compounds and other micro-contaminants by means of ozone and ultrasonic treatment. One of the findings is that, as expected, aromatic compounds...

We present a compact Laser Ultrasonic (LU) receiver based on two-wave mixing in photorefractive materials, for simultaneous measurement of the out-of-plane and of the in-plane displacements (2component). By taking advantage of recent developments in electronic processing, we achieved a compact optical architecture using only a single collecting aperture and a single laser probe beam. Complement...

The circulatory response to ultrasonic irradiation of the upper limbs was measured under controlled conditions by venous occlusion plethysmography. Volumetric blood flow changes were related to temperature measurements in the treated tissues. Ultrasonic irradiation of the extremities was not found, per se, to be an effective means of promoting a sustained increase in blood flow. The information...

Scanning electron microscopy, 3D optical surface profilometry, as well X-ray diffraction and backscatter analysis were implemented for studying the effects of both ultrasonic impact treatment (UIT) electrospark (UIET) procedures on microstructure, phase composition, mechanical tribological properties Ti-6Al-4V samples fabricated by wire-feed beam additive manufacturing. It was shown that he UIE...

A one-sided, nondestructive, ultrasonic technique for monitoring the setting and hardening process of concrete has recently been developed. The technique is based on monitoring the reflection coefficient of ultrasonic transverse waves at the surface of a laboratory scale hardening concrete in steel molds. The technique has been shown to reliably estimate the rate of strength gain of concrete un...