The influences of fermentation temperatures, agitation rates, and additions of carbon sources, nitrogen sources, vitamins and minerals on the production of kefiran by kefir grains’ lactic acid bacteria was studied over a series of experiments. The main aim of the work was to increase the exopolysaccharide (EPS) production where customised milk was used as the fermentation medium. It was proved that the controlling of culturing conditions and the modifying of fermentation medium conditions (i.e., carbon, nitrogen, mineral sources, and vitamins) can dramatically enhance the production of the EPS. The temperature and agitation rates were critical for kefiran production during the 24h cultivation of grains our optimised conditions being 25°C and 80rpm, respectively. In addition, when optimising the effects of additional nutrition, it was discovered that lactose, thiamine, and FeCl3 led to the maximal production of EPS. The results indicated that nutrients can be utilised to improve the production of EPS and that good kefir grains’ growth does not appear to be a determining factor for a high production yield of EPS.
COBISS.SI-ID: 16645142
This contribution presents and discusses two multi-objective optimisation approaches considering total (direct and indirect) effects on the environment.Sustainability metrics, conventionally measuring direct harmful effects on the environment, are now upgraded with indirect effects in order to measure the unburdening the environment, e.g. due to the substitution of harmful with benign products. The first approach, based on a relative direct sustainability index, is now upgraded to a total sustainability index, and the second one, based on a concept of eco-cost and net profit, is extended to arecently introduced concept of eco- and total profit. These approaches are illustrated through a case study of the supply chain synthesis for producing biogas from organic and animal wastes. The results indicate that considering total effects enables obtaining more realistic solutions, than in those cases when only direct effects are considered. An appropriate trade-off between economic and environmental criteria can be established when performing a maximisation of total profit.
COBISS.SI-ID: 16020502
This study presented a multicriteria optimisation of a regional network producing bioproductsand food from biomass, including direct (burdening), indirect (unburdening) and total (direct + indirect) footprints. The generic model for the optimisation of regional networks for the production and consumption of energy from biomass within the entire production network (Čuček et al., 2010) was upgraded for the simultaneous evaluation of sustainable development based on life cycle assessment. More profitable and environmentallyfriendly solutions were obtained when considering total footprints and not only direct footprints.
COBISS.SI-ID: 15839766
This contribution presents a simplified and more practical version of an objective dimensionality reduction method within multi-objective optimisation - a Representative Objectives Method. This method is based on similarities between several objectives in order to reduce the number of objectives to a minimum number of representative objectives. This method can be applied to different direct and total objectives. In this contribution the selected objectives are annual profit and total footprints. Total footprints are the sum of direct and indirect footprints where the direct footprints only consider the burdening of the environment, whilst the total footprints consider both the burdening and unburdening of the environment. This dimensionality reduction method is applied during a demonstration case study of regional supply chains regarding the evaluations of different total environmental footprints. This case study indicates that this simplified version of the Representative Objectives Method is easy to apply and enables the user to more easily understand multi-objective optimisation solutions. It represents a practical tool for performing the dimensionality reduction of criteria during the economic and environmental optimisation of different problems when considering total environmental footprints.
COBISS.SI-ID: 17446678
This review summarizes the corrosion inhibition of steel materials in acidic media. Numerous corrosion inhibitors for steels in acidic solutions are presented. The emphasis is on HCl solutions, lower-grade steels, and elevated temperatures. This review is also devoted to corrosion inhibitor formulation design % mixtures of corrosion inhibitors with (mainly) surfactants, solvents, and intensifiers to improve the effectiveness of individual compounds at elevated temperatures. The information presented in this review is useful for diverse industrial fields, primarily for the well acidizing procedure, and secondly for other applications where corrosion inhibitors for steel materials are needed.
COBISS.SI-ID: 17802774