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  • Author: Attila Gergely x
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Abstract

This paper discusses the design steps, working principle and structure of a small-scale thermo-plastic extrusion machine that will be used in a laboratory at the Sapientia University. The aim of the laboratory is to present the polymer processing technologies by student-built machines and to stress the importance of plastic recycling. In order to recycle plastic parts a grinding process is necessary, followed by extrusion. During the process the machine melts the polymer and extrudes a filament that can be converted into granulates or used as it is. The structure of the extrusion machine is rather similar to that of a commercial one, however it focuses on presenting the manufacturing principles and cost effectiveness.

Abstract

The aim of this paper is to present a granulate manufacturing machine that will be used for recycling plastics in a laboratory at the Sapientia University. In order to produce granulates of recycled plastics the plastic part has to be ground and then extruded. The extruded polymer filament then can be converted to granulates. We present the working principle, design steps, structure and 3D model of a small scale granulate producing machine with a cost-effective approach

Abstract

The price of firewood has increased substantially in the last couple of years due to the high volume of export. The branches and smaller diameter pieces are considered leftovers and are not exportable, however they are suitable as firewood. Chainsaws are used to cut the larger diameter wood, but this way is not efficient for cutting up branches and smaller diameter wood pieces. In this paper we present the structure, working principle and the 3D model of a machine that can be used to chop smaller diameter wood branches in a simple and efficient way.

Abstract

The aim of this study is to conclude the experiences of the maintenance practice of an artificial thermal lake. The first years (2015-2017) of the development of the lake were analysed and evaluated along the following questions: a) What kind of design processes and maintenance interventions are related to the process of fitting the lake into the landscape? b) How have the ecological conditions of the lake evolved in the past period (zonation, succession, plantation and colonization)? c) Which general experiences could be gained from the operation of this artificial thermal lake this far? The authors of the present study were already engaged in the planning process, participating in the preparation of four different design documentations. The planting design and the maintenance instructions were based on a physico-chemical monitoring, phytoplankton, zooplankton and macroinvertebrate sampling, and machrophyte assessment. The significant processes during the three years of the lake are presented by functional groups of biota, separately assessing the characteristics of the changes of macrophytes. In 2017 an individual macroinvertebrate assessment was done, moreover a fish die-off occurred in August 2017, which are mentioned separately as well. The data in total suggested that the water of the lake is highly hypertrophic, further machrophyte introduction can prevent the plant nutriments to be absorbed by algae. Partly the algal growth but also the unlucky coincidence of other factors (e.g. high water temperature, cold weather front, maintenance problems) led to the die-off of the spontaneously overpopulated fish stock in 2017.

Abstract

Field surveys are essential in the Hungarian motorway planning process so that it would be possible to assess their impacts on the landscape, since the available databases are insufficient in respect of listing all the valuable elements of the landscape. The aims of the research are to analyse the impacts of the planned M30 Motorway (located in north-eastern Hungary) on the landscape, to enumerate the cultural and natural valuable elements of the landscape near and within the area to be expropriated, to explore the possibilities of their protection and to outline the possible land use conflicts likely to arise after the implementation of the motorway. The main sources used for the research were: landscape, green space management and environmental protection studies made for the modification of the affected settlements’ urban plans, field surveys alongside the entire track, and existing environmental databases. In the case of M30 motorway, the chosen corridor was mostly acceptable in the sections where the motorway track leads along the track of the existing Main Road 3, because it is fitted to an existing linear artificial landscape element, it is basically on the border of two natural micro-regions and can also fit into the existing land use structure. Nevertheless, it is not considered to be the best choice in places where it separates vineyards from vine cellars, where it is located within 50 meters from residential areas or where it passes through small plot vineyards or horticultural areas instead of the arable lands of the nearby plain.

Abstract

Aim: To evaluate the value of a more closed perioperative ECG follow-up in the investigation and forecasting of cardiovascular events during and after hospital admission.

Methods: We included in the study 30 asymptomatic patients from cardiac point of view (14 women, 16 men, mean age 63 years), who underwent total hip arthroplasty. ECGs were performed on the day before surgery, on the day of surgery, after the intervention, and on the 3rd day. We looked for the correlations between ECG changes and clinical events.

Results: The commonest postoperative new ECG changes were QTc prolongation (14 patients -46,6%) and sinus tachycardia (8 patients - 26,6%). There were no major cardiac events during hospitalization, and we found possible correlations in two cases between perioperative ST-T changes and postdischarge clinical events: one exitus and one case of ischemic heart disease.

Conclusions: Our data do not support the efficacy of a more closed, routine ECG follow-up in the studied, low risk patient population, but new perioperative ST-T changes always have to be taken into account.

Abstract

The effective recycling of polymer materials remains unresolved to this day, and this has had a devastating effect on the environment. This study examines an alternative method to PET recycling that is the generation of polymer fibers and fiber mats for filtration applications. The electrospinning instrumentation used in this study had to be designed and built in order to carry out the research. We have managed to produce PET fibers with 200-600 nm diameter, and free-standing fiber mats that could potentially be used in filtration applications.