Design of compositions and types of structures of injection molded dispersed filled thermoplastics with good processability and high strength

The issues on the assessment of rheological properties of dispersed filled polymer composite materials (DFPCM) in terms of generalized parameters of disperse structure are considered. The dependences of pressure loss during injection molding of thin-walled DFPСM products with different types of disperse structure: dilute, low-filled, medium-filled and high-filled systems are given for the first time. It has been established that to obtain DFPCM based on thermoplastics with good processing properties and products with high strength, it is necessary to create materials having medium-filled type of structure and the generalized parameter Θ ≈ 0.5-0.6 vol/vol. The algorithm for calculating the dispersed filler content with known basic properties to provide a given type of DFPCM structure is proposed.

Research of Disperse Composition of Air-and-Water Mix Generated by Ejector Aeration System During Wastewater Floatation Treatment

The process of waste water treatment by floatation using ejector system of aeration has been considered in this paper. The system’s main shortcoming has been noted: receipt of large bubbles with a diameter about 1 mm, that not always allows get a high performance of cleaning. It has been noted that the most effectively the process of floatation treatment for industrial sewage from fine pollutions is performed when the bubbles’ sizes are less than 100 microns, and when there is a big range of pollutions in water it is reasonable to receive the bubbles with a wide disperse structure. The carried-out overview of Russian and foreign sources has demonstrated that the main shortcomings of existing dispersion devices used for crushing of the bubbles generated by the ejector is insufficient dispersion extent in case of low gas content, work instability, technology complexity. For sewage treatment process intensification and remedial action of the existing devices has been offered a combined aeration system consisting of ejector and original dispersing device. On laboratory installation have been conducted experimental studies on determination of disperse composition for air-and-water mix generated by the offered aeration system. The received results confirm a possibility for receipt of fine bubbles in the range of 20–300 microns with a degree of bubbles of fraction less than 100 microns up to 80 %, and with an average diameter of 60–80 microns. A feature of the bubbles’ disperse structure has been noted: allocation from it several groups of bubbles with different values of average diameters. This feature can be used for intensification of process for water treatment from pollutions with various floatability degrees. Dependences of researched characteristics on dispersant’s diameter and height have been presented. They allow perform a choice of dispersant’s geometrical parameters for receipt of the air-and-water mix’s required disperse composition aimed to management of floatation process.

CURRENT STATE OF THE SEA SYSTEM IN BRAZIL: A COMPARATIVE STUDY

After the first applications in the early 1990's, the practice of SEA in Brazil has been going through a slow, but important evolution. In this paper we elaborate on the main aspects of this evolution, based on the findings of a comparative study that put the practice of SEA in different contexts into perspective. SEA systems considered included consolidated (UK, Spain and Portugal) and unconsolidated (South Africa, Mexico, Angola and Mozambique) systems. The Brazilian system is characterised by a disperse structure and a low level of self-organisation, which makes integration with plan making difficult while, at the same time, stimulating "flexible" and "adaptive" SEA processes. We suggest that the lack of both, institutional drivers and a clear procedural framework are hindering further development of the Brazilian system.