The introduction of invasive aquatic species in new environments has been identified as one of the four biggest threats to the world's oceans causing serious threats and harm to both ecology and human health. There is a major exchange of ship’s ballast water over longer distances between continents and regional seas, and it has been known for decades that ballast water transfers organisms to new ecosystems, where the strongest, most aggressive and adaptable species can survive and become invasive under favourable conditions. The focus of the research is to study available ballast water control technologies to determine their suitability and effectiveness in the reduction of harmful aquatic organisms and compounds in the Baltic Sea.
Andrii Grekhov, Vasil Kondratiuk and Svitlana Ilnitska
MIMO-OFDM models of RPAS communication channels based on LTE Standard were built. Dependencies of the BER on the SNR for Extended Pedestrian A and Extended Vehicular A models using 2-by-2 multiple antennas were obtained. Dependencies of the BER on the SNR for different levels of Frequency Offset at satellite transponder were studied.
Common Agricultural Policy represents the main instrument of the European Union for the development of agriculture and rural areas. European funds are vital for the productivity and competitiveness of agricultural holdings, as well as for the transfer of agricultural knowledge and innovation. Supporting small and young farms is essential for the vitality of rural areas and for the renewal of generations of farmers. The aim of this work is to transfer agricultural knowledge in order to improve the productivity of agricultural holdings, especially among young farmers and small farms. We implemented training program through European funds related to Measure 1. “Actions for knowledge transfer and information actions” from Rural Development Programme of Romania. The characteristic of 100 participants and their responses were analyzed. Most of the participants were young people up to 40 years old (59%). The vast majority of the participants were from the rural area and only 17% were from the urban area. 53% from participants were strongly agree with the fact that level of knowlegde influence farm productivity. Actions for knowledge transfer improve the adaptation of farmers to the new challenges of agriculture, as well as productivity.
All castings can have defects caused by, for example, deviations in material characteristics, structure or properties, but the skillful use of available technologies and quality management tools allows for the detection and elimination of casting incompatibilities as well as the prevention of their recurrence in the future. The aim of the article was to analyse the types of defects in castings, locate the areas with the most frequent occurrence of defects and identify the reasons for the presence of defects in castings of the control panel and its cover. The paper presents the usefulness of a combination of quality management instruments for diagnosing material discontinuities in the analyzed castings.
Autonomous underwater gliders are buoyancy propelled vehicles. Their way of propulsion relies upon changing their buoyancy with internal pumping systems enabling them up and down motions, and their forward gliding motions are generated by hydrodynamic lift forces exerted on a pair of wings attached to a glider hull. In this study lift and drag characteristics of a glider were performed using Computational Fluid Dynamics (CFD) approach and results were compared with the literature. Flow behavior, lift and drag forces distribution at different angles of attack were studied for Reynolds numbers varying around 105 for NACA0012 wing configurations. The variable of the glider was the angle of attack, the velocity was constant. Flow velocity was 0.5 m/s and angle of the body varying from −8° to 8° in steps of 2°. Results from the CFD constituted the basis for the calculation the equations of motions of glider in the vertical plane. Therefore, vehicle motion simulation was achieved through numeric integration of the equations of motion. The equations of motions will be solved in the MatLab software. This work will contribute to dynamic modelling and three-dimensional motion simulation of a torpedo shaped underwater glider.
Natalia Majca-Nowak, Ewelina Kluska and Piotr Gruda
The article presents research conducted with the project: ‘Additive manufacturing in conduction with optical methods used for optimization of 3D models’’ . The article begins with the description of properties of the materials used in three different additive technologies – Fused Deposition Modelling (FDM), Selective Laser Sintering (SLS) and Material Jetting (MJ). The next part focuses on the comparative analysis of macro- and microstructure of specimens printed in order to test selected materials in additive technologies mentioned above. In this research two types of specimens were used: dumbbell specimens and rectangular prism with hole specimens. In order to observe macrostructure specimens, they were subjected to load test until it broke. In the case of observing microstructure, they were cut in some places. Each of described additive technologies characterizes by both different way of printing and used materials. These variables have a significant influence on macro- and microstructure and fracture appearance. FDM technology specimens printed of ABS material characterized by texture surface appearance. SLS technology specimens printed of PA12 material characterized by amorphous structure. MJ technology specimens printed of VeroWhite Plus material characterized by fracture appearance which had quasi- fatigue features. The microstructure of these specimens was uniform with visible inclusions.
The article presents the description of technological trials and the results of three methods of machining carbon fiber reinforced composites panels. It also reviews the literature concerned heat affected zone in composites and its influence on material properties. As a part of the research, the cutting method using diamond coated saw was tested, as well as the milling method with two different types of carbide milling cutters. The processing of the panels was done using 4-axis CNC machine with special adapter for cutting discs in Composite Testing Laboratory (Center for Composite Technologies, Warsaw Institute of Aviation). The methods were compared in terms of machined edge quality and panel temperature during the processes. For this purpose, thermocouples were mounted into panels. Records from thermocouples were included. Edge quality and surface roughness have been checked by microscopic observation. Additionally, samples machined by each evaluated processing method were tested using differential scanning calorimetry (DSC). The method was used to determine the glass transition temperature of the tested material. The article conclusions contain a comparison of three processing methods in terms of cutting quality, process temperature, processing method productivity as well as DSC tests results.
Dušan Gaňa, Tatiana Liptáková and Lenka Markovičová
A constant increase in the production of plastic products is a major cause of general environmental pollution. The past decade recognized how significant recycling plastic waste and the development of biodegradable materials is. This paper takes a new look at reducing the amount of plastic waste in the environment. Plastic bottles are “dressed” in a special PE (polyethylene) foil before filling. After the content is consumed, the foil is removed of the bottle. Such foil can be used for transporting other products more than once. The work focuses on the investigation of the changes in properties of the light density polyethylene (LDPE) foils caused by forming during their application to the bottle. It was decided that the optimal method for this investigation was to compare the mechanical and rheological properties PE foils before and after their application to the bottle.
Integrating electric vehicles in a supply chain and distribution is a viable option when special conditions such as short distance road distribution and environmental considerations as well as small amounts of goods enabling delivery with delivery vans are met. In this paper, possibility of investment in electric vehicles for distribution of local food will be examined and analysed. Safety concerns in electric vehicles will also be addressed and accident consequences and vehicle safety will be analysed and compared with conventional vehicles that use internal combustion engines.
Customers and their perception towards service are considered as a determinant of service failure, and so, service failure and its prevention must be looked into from the perspective of the customers. This paper presents a customer-centric service failure prevention framework, which aims to provide a holistic way of service failure prevention by integrating service delivery assessment and failure analysis from a customer perspective, encompassing failure identification, assessment and prioritization of failures as a basis for corrective actions. Customer journey, service clues, and customer oriented-FMEA are employed to develop the proposed framework. The approach was applied to an enrolment process showing that using customer journey assists in determining customer processes, needs, wants and touch points in the service, and when used together with service clues further facilitates systematic and effective unveiling of potential failures that are important to customers. Assessment of failures and its prioritization with customer perspective leads to better prioritization that is reflective of the voice of customers. The case study shows that higher risk is imposed by actions emanating from the employees, reinforcing further that service failures not only concern functionality of the service but equally important also are the encounter of customers with service employees and the environment.