Table of Contents

  • SCIENCE

    • MICROBIAL CLEANING OF MINE WATERS FOLLOWED BY ELECTRICITY GENERATION

      pg(s) 10-11

      Acid mine drainage waters polluted by iron, several non-ferrous metals (mainly copper, zinc and cobalt) and sulphates as the main pollutants were efficiently treated by a lab-scale passive system consisting of an alkaline limestone drain and a permeable reactive multibarrier connected in a series. The multibarrier was filled by a mixture of solid biodegradable organic substrates (mainly of plant biomass) and was inhabited by different metabolically connected anaerobic microorganisms (mainly different heterotrophs including some iron-reducing and sulphate-reducing bacteria). The effluents from this system were rich in soluble organic compounds and were treated in a microbial fuel cell in which consortium of electrochemically active microorganisms used these compounds as donors of electrons for electricity generation.

  • BUSINESS

    • EVALUATION OF CUSTOMER RELATIONSHIP MANAGEMENT SELECTION CRITERIA

      pg(s) 12-14

      This research is about evaluation of Customer Relationship Management (CRM) selection criteria for construction industry in Turkey. It is difficult to implement CRM in construction industry because of its characteristics specifications like transactions and operations volume both in customer and company site. Therefore CRM selection is also as important as CRM implementation. The aim of this research is to evaluate the criteria for CRM selection and then determine the weights of the chosen criteria. The method is going to be Analytic Hierarchy Process (AHP).

    • THE CROWDFUNDING PROCESS – AN UNDERESTIMATED OPPORTUNITY IN BULGARIA

      pg(s) 15-17

      This article represents a review of good practices in crowdfunding. The subject is the opportunities which create conditions for using the crowdfunding process by entrepreneurs and perspectives for implementation of this good practice in Bulgaria. The concept of crowdfunding in Bulgaria is mentioned a lot but barely in the last few years can be observed the standing out of pronounces examples and good practices. The appearance of financial instruments for starting technological companies promises to become an accelerator for the entrepreneur ecosystem in Bulgaria. This paper examines how different platforms in crowdfunding campaigns influence the entrepreneur’s choice of targeted crowdfunding goal.

    • RISK ASSESSMENT FOR THE PRODUCTION PROCESS

      pg(s) 18-21

      Risk management constitutes currently one of the most important elements of the management of an enterprise, which is crucial to its security and continuous improvement. This is a several-stage process, and its implementation should systematic and principled in character. The article sets out the risk assessment for activities performed in conjunction with individual operations of a manufacturing process, and specifically, the book production process. The risk assessment was preceded by the identification of hazards to technological, transport and control operations, followed by their analysis using an indicator method. Operations have been identified, which are characterized by the highest risk, and preventive and prophylactic actions using various control measures (technical, organizational, legal, individual and collective) have been proposed. Risk assessment for a task is a primary outline for the use and implementation of risk management issues that go beyond the commercial risk assessment in an enterprise.

    • EXPLORING THE IMPACT OF IRRIGATION TECHNOLOGIES ON THE YIELD OF HYBRID SUNFLOWER VARIETIES

      pg(s) 22-30

      A Polish experience with 10 hybrids of sunflower field was made on the Chelopechene Field, Sofia, on cinnamon forest soil. Sunflower hybrids are grown under non-irrigating conditions and under irrigation conditions with drip irrigation and microwaving.

      The meteorological conditions during the study period determined the number of irrigations and the size of the irrigation and irrigation norms of the culture.

      It has been found that the yields obtained under irrigation conditions are higher than 13 to 46%, with drip irrigation giving better results than sprinkling.

      The Maritsa, San Luka and A58xC23 hybrids have been shown to be suitable for growing in non-irrigated conditions, while the hybrids "Vokil", "Michaela" and "Maritsa" hybrids are irrigated.

  • SCIENCE

    • EFFECT OF PLASMA DENSITY ON RESIDUAL BACTERIAL NUMBER AND APPLIED VOLTAGE

      pg(s) 3-5

      Plasma basic ion implantation (PBII) with high negative voltage pulses has been applied to test specimens in a sterilization process as a technique suitable for three-dimensional workpieces. Pulsed high negative voltage was applied to the electrode in this process at the gas pressure of oxygen. It was reported that the PBII process reduced the numbers of active Bacillus pumilus cells using self-ignited plasma N2 gas generated by only pulsed voltages. The number of bacteria survivors was reduced by 10-5with a few min exposure. As the ion energy is the most important processing parameter, a simple method to estimate the oxygen ion energy calculated using distribution for oxygen in Si implanted by PBII was estimated. In this work, the Effect of Plasma Density on Residual Bacterial Number and Applied Voltage is studied.

  • BUSINESS

    • IRRIGATION WATER PRODUCTIVITY FOR RASPBERRIES GROWN IN DRIP IRRIGATION CONDITIONS

      pg(s) 31-34

      To determine the irrigation water productivity for raspberries during their cultivation in the soil-meteorological conditions of the area of the village of Chelopechene – Sofia, studies have been carried out with drip irrigation of a plantation with the variety "Lyulin". Various regimes have been studied – from full satisfaction of the daily needs of the culture to water, to irrigation with 20% and 40% reduction in irrigation regulations.

      The meteorological conditions during the study period determined the number of irrigations and the size of the irrigation and irrigation norms of the culture.

      On average, over the survey period, the highest yields were obtained with the watered with 100% irrigation norm option. The increase in yields resulting from the irrigation is about three times the non-irrigated option in surface drip irrigation.

      The highest irrigation water productivity of 4.3 kg of raspberries per cubic meter of water is obtained in variants irrigated with a 40% reduced irrigation rate.

  • SOCIETY

  • SCIENCE

    • AN APPROACH FOR CLUSTERING SOCIAL MEDIA TEXT MESSAGES, RETRIEVED FROM CONTINUOUS DATA STREAMS

      pg(s) 6-9

      Using k-means clustering algorithm, a new approach to handle evolving topics and discussions in social media environment is proposed. Different segmentation techniques and applications to handle large volumes of data are explored. Relevant works that consider using fading functions and half-life weight measurements as a tool to remove inactive clusters are discussed. A set of rules and a controlling variable called time to recover are introduced as a simple means of managing cluster lifecycles. Short case study is conducted with Twitter data retrieved between the 19th and 22nd of January 2018.