International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

When location was estimated using Sigfox’s Atlas Wi-Fi, the estimation error is several hundred meters. Meanwhile, when location was estimated using the Wi-Fi media access control (MAC) address and HERE’s API, the estimation error was ~10 m. In an Internet of Things device that obtains the Wi-Fi MAC address, the combination of exp32 and 100a was ~1/5th of the combination of Arduino R4 and Sigfox Shield.

An important aspect in organizing acoustic emission monitoring is the analysis of recorded data and selecting useful information. Despite noise suppression using frequency methods, its quantity in the recorded information can reach 99% because the process of degradation during operation typically progresses slowly, whereas the presence of acoustic noise is an inherent attribute of the technological process.
Noise suppression after data recording is carried out within the framework of the monitoring system’s software, although filtering algorithms may be specific to each application.

Insuring a sustainable development of wind energy production and consumption is challenging and highly important for /achieving of EU 20/20/20 goals for Bulgaria. Wind energy has been seen as a clean and environmentally friendly in comparison with conventional energy sources, but there are still some conflicts between wind energy project development and environmental protection goals that should be enlighten and solved. One possible way is to enhance the process of wind energy projects’ location identification. The current research is focused on identification and classification of criterion that could be used in this process. The legal requirements regarding wind energy projects’ location are analyzed and presented. Additional requirements regarding environmental protection and biodiversity conservation are identified and defined as criterion. A set of measurable indicators related to each criteria is established and proposed in this paper.

A historical aspect of uranium mining in Bulgaria has been made until its eradication in 1992. Described are the measures taken pursuant to Decree-Law No. 74 / 27.03.1998 on the liquidation of the consequences of uranium mining and processing and the gaps to be eliminated in this regard. Up to the end of uranium mining in 1992, the annual uranium yield was 660-680 t, of which 430 t was obtained by geotechnical method – drilling with drilling of the sand-type uranium. They are poor in uranium (below 0.05%), but with a few times cheaper yields (an average of $ 40 / kg for 1970-1990). Possible new uranium extraction from this type of field and mine wastewater could reach 350 t per year at a value not exceeding 80 $ / kg. It is possible to investigate and prove 40-50 000 tons of new uranium ore deposits in Bulgaria mainly in the sand-type deposits at a depth of up to 650 m.

Choosing the right warehouse location is very important question which should be considered with great care, because it has a direct influence on the operating cost. For solving this problem many methods are on disposal. According to the way of determination of new warehouse location these methods can be divided in two groups’: qualitative methods and quantitative methods. Quantitative methods are often used in practice from the reason greater objectivity and possibility to analyse obtained results. Most often used methods are: gravity method, load distance method, Weber problem and many others. For calculating of distance in the load distance method two approaches are in use rectilinear distance and Euclidean distance. Neither one of these two approaches credibly describes transport routes because they not taken into consideration any physical obstacles that might occur between potential warehouse locations. With the goal to determine the influence of distance calculation on the result of the load distance method, choice analysis of optimal location of warehouse for retail stores, shops in the urban area was performed and presented.

Analysing of material flows within the boundaries of the production system it is possible to conclude that the sources and sinks of those material flows are storages. In those storages in the function of the kind and the type numerous processes are implemented. These storage processes along with the material handling processes are responsible for quantitative and dynamic balancing of material flows and as such have a significant impact on the total cost and productivity of the production system. Due to the above reasons, the design of storage is an important task which needs to be adequately accessed. Regardless of the kind and the type and the associated processes within storage one of the main activities in the design phase of storage is to define its location, with special emphasis on interaction with other elements of the production system (production and processing equipment, material handling equipment and devices, etc.). Namely, selection of the right location, among other things ensuring the necessary conditions which will make the process of storage to meet the technical and technological, economic, organizational, IT and other requirements upon it.