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Romanian aquaculture can be economically sustainable and viable if the farm is profitable, the farm's income is secure, and the products are accepted by customers. In many cases, improving environmental sustainability can lead to optimizing economic sustainability. For example, a more efficient use of food and nutrients or reduced water and energy consumption are not only beneficial for the environment, but can also reduce costs. Growth in polyculture system, which represents the growth of several species of fish in the same space (pond, pool, basin, etc.), and diversification of supply can increase consumer confidence and thus economic sustainability. The diet must provide the fish with the nutrients necessary for growth (proteins with a plastic role) and provide the energy necessary for physiological processes. Quality food ensures good development, facilitates reproduction and prevents extremely harmful diseases in an aquaculture system. The paper presents a series of experimental recipes for pelletized feed made using an experimental model of small capacity. Nutrient pellets made for feeding fish from the Cyprinid family were analyzed in terms of gross energy value, ash content, moisture, mechanical durability over time, bulk density etc. [ABSTRACT FROM AUTHOR]

Energy efficiency of modern industry machinery imply using adaptive electronic driving modules, based on digital processing units, in order to offer superior machine capabilities through firmware updating. It is a well-known fact that classic hydraulics installations mounted on industrial machinery are sometimes too complex and difficult to reconfigure and in some cases impossible. Industrial machines need to be flexible and energy efficient, leading to real challenges for industrial designers. Standardized hydraulics equipment and digital driving electronic modules are still a solution to modern industrial needs, but the energy efficiency is poor. Complexity of hydraulics installations has been, somehow, passed to electronics driving modules but leaded to a rapid increase in control system's complexity. Hydraulics manufacturing companies promote nowadays the concept of digital hydraulics systems as the answer to modern technical challenges. In this paper, the authors have investigated the possibility of using the digital hydraulics concept in replacing conventional electrohydraulic directional valves, in the case of a waste baling press. It will be underlined main advantages and disadvantages of digital hydraulics over classic hydraulics. [ABSTRACT FROM AUTHOR]