Ecoterra, No. 5, pp. 24-25, 2005
Liviu SUCIU, Vasile COSMA, Mircea CRĂCIUN
S.C. ICPE Bistriţa S.A.
Ioan PLATON, Natalia ŢIGĂUAN
Staţiunea de Cercetare şi Dezvoltare pentru Pomicultură Bistriţa
Abstract: The controlled atmosphere storehouses are the most modern preservation enclosures, where the maximum duration of maintaining the quality of the fruit and of the vegetables is achieved. The installation that we describe here and which has been used in the process of preserving fruit for 9 or 12 months, with perishability percentages of only 2-6 %, was made and tested at the Bistriţa Fruit Growing Research and Development Station. At the level of our region, such an installation was also made in Reghin, more exactly in the Dedrad village, Mureş county, at farm 14 of the Pomicola Batos Ltd. trading company. The installation is composed of the following subassemblies: the device for disinfecting the air with nitrogen, the aggregate for causing coldness, the humidifier, the evaporator, the exhausting fan, two ultrasounds generators and the control panel, which were mounted on the wall both in the control room and in the refrigerating room. After putting the apple containers in the storing room, the door is hermetically closed. The coldness aggregate, the humidifier, the nitrogen generator and the automation & control panel are put into function. The data relative to the temperature, the humidity, the maximum and minimum allowed concentration of carbon dioxide, oxygen and nitrogen are entered. These data will be kept in the programmed intervals by means of the sensors. As a result of the experimentations performed by using the pilot installation described above, the findings were that the disinfection with nitrogen did not affect the properties of the apple (table 1) and, plus, it brought forth a lower perishability than in the storehouses with no disinfection with nitrogen, reaching a perishability value lower than 3 % for a 9 month preservation period. The automation of the installation brought along a diminishment of the energetic consumption, that is to say of the preservation costs. By incessantly monitoring the values of the humidity, of the temperature and of the concentration of oxygen, carbon dioxide and nitrogen on a computer, the result was a better surveillance of the functioning of the installation in best conditions.
Key words: controlled atmosphere, monitoring, ozone generator
Ecoterra, No. 5, pp. 26-27, 2005
Benoni LIXANDRU, Gabriel TRANDAFIR
Facultatea de Zootehnie şi Biotehnologii Timişoara
R.A. Apele Române, filiala Banat, Timişoara
Abstract: The waters in the Ier Valley have got a partially oligotrophic structure, which is generally mesotrophic, with some eutrophised areas. The eutrophisation process reaches its maximum development in summer, generally in July, after which the intensity gradually decreases towards autumn, alongside with the drop of the temperature. Besides the dejections of the protected ornitho-fauna, an important source of phosphorus is represented by the domestic palmipeds, on account of the higher values of phosphorus in the points where the flocks of these birds with a free access in the area have been often noticed. The intensity of the aerobic mineralization process is higher in summertime, especially in the sunny locations of the water puddles. In summer, the mesotrophic and eutrophic type values of the phyto-planctonic biomass are approximately 75 % from the number of the investigated samples. Towards autumn, the values of the eutrophisation indices diminish towards the mesotrophic-type ones, with some exceptions in certain areas.
Key words: Ier Valley, trophic structure, ornithofauna, mineralization
Ecoterra, No. 5, pp. 28-29, 2005
Zoltan BOCSKAI, Ancuţa CICEU, Claudia CICEU, Adrian BĂLAN
S.C. ICPE Bistriţa S.A.
Abstract: The work presents the putting on of a modulus of micro-farm for the introduction of a valuable species of African catfish (Clarias Gariepinus) in the Romanian aquaculture and the drawing up of the technology of a hyper-intensive breeding. The breeding modulus will have a capacity of 2 tons of fish for a useful volume of 8 cubic metres of water. The planned breeding farm functions in a closed system with thermally and hydro-chemically conditioned re-circulated water, which allows the practising of some unusual high densities, i.e. 250 and 450 kg of fed living fish/1 cubic metre of volume for the breeding tank (approximately 250-450 kg of fish/550-750 kg of water).
Key words: African catfish, micro-farm, hyper-intensive breeding
Ecoterra, No. 5, pp. 32-33, 2005
Abstract: The engineering of quality, according to Taguchi, consists in determining, from a multitude of possible technical solutions, the one that offers the maximum ‘robustness’ at the lowest cost price. For this purpose, he developed a new ‘philosophy’ of the products/processes quality, by introducing new concepts, terms and methods, part of them completely original (such as the quadratic function of the quality losses, the S/N ratio, the use of the experimental models for reducing dispersion and so forth), part of them being founded on some well-known things (such as R.A. Fisher’s design based on an experimental model, Demings and Juran’s theses on achieving quality). The optimization of the products/processes according to the Taguchi methods is one of the newest techniques relative to quality, which begins being applied on a large scale ever since 1980. Its essential characteristic, that is maximum quality at a minimal price, recommends it as an extremely necessary means for the industrial development and notably for the growth of the small and medium companies.
Key words: quality engineering, Taguchi methods, product and process optimization
Ecoterra, No. 5, pp. 33-34, 2005
Dan ROBESCU, Constantin MIOC
Universitatea Politehnică din Bucureşti
Abstract: The biological purification of the waste waters is a chemical and biochemical process based on the metabolic activity of some groups of aerobic bacteria. Within this activity, the organic matter based on carbon is mineralized until the carbon dioxide and water. The process, if well conducted and mastered, can have an efficiency as high as even 98 %. The measurements performed in the biological treatment plants have shown that contradictory and irreproducible results have been appearing for several years, which has led to the idea of chaos that may be noticed in practice. Thus, most of the times, identical values of the quality parameters upon the admission in the waste water treatment plants happen to lead, the moment of the evacuation, to some results that are totally different, hard to explain and to justify. In addition, during exploitation there also appear situations where some totally different values upon the entrance lead to some identical results the moment of the evacuation. This work here intuitively describes the way in which chaotic behaviours in the evolution of the dynamic system described by the generalized equations are likely to appear.
Key words: waste water, biological purification, aerobic bacteria, efficiency, generalized equations