Search results

The purpose of this study was to examine the impact of five key build parameters – layer thickness, deposition angle, infill, extrusion speed and extrusion temperature, and their interactions – on the maximum flexural force in specimens which are made of polylactic acid (PLA).

Through a previous study on the flexural properties of PLA specimens, a statistically significant effect of layer thickness was indicated, requiring further experimentation to establish the values of quadratic term in the model, as well as to perform optimization. Instead of performing a conventional Central Composite Design, a novel, definitive screening design (DSD) was used as statistical method. DSD allowed the reduction of the number of runs required for optimization while minimizing aliasing.

Significance of deposition angle and infill as main effects was established. Moreover, significant two-way interactions between infill/layer thickness and infill/extrusion speed were detected and discussed. The optimization procedure showed that minimum level of deposition angle, maximum levels of extrusion speed and infill and near mid-level of layer thickness yield maximum flexural force.

In this study, the three levels of infill were 0.1, 0.2 and 0.3, which corresponds to 10, 20 and 30 per cent of infill, respectively. In everyday practice, infill is usually kept within this range since it allows time-efficiency, i.e. significant reduction of build time. Though, unsurprisingly, higher infill is positively correlated with flexural strength, this study provides practical directions for optimal selection of other key parameters when working with low infill values.

Optimal 3D printing with low infill can contribute to lower material waste and pollution, while PLA plastic’s biodegradability remains high on the environment protection agenda.

According to available literature, no previous studies have investigated the FDM extrusion of PLA material using a combination of low infill, deposition angle, layer thickness, extrusion speed and extrusion temperature.

Examines the sixteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Examines the fifteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

The purpose of this paper is to analyze sustainability of the constructed projects (Djerdap 1 and 2) and feasibility of the planned ones (Djerdap 3) on the river Danube in the region of Iron Gate, with multi-criteria focus on technical, economical and environmental parameters.

The main objectives were achieved by using the methodology of a holistic multi-criteria approach. Electra method was applied. The design of the three projects on the international Danube River were analyzed, from technical, economical and environmental point of view, with the goal to manage a higher involvement of renewable resources.

The results of the research imply that the most profitable technical solutions cannot reach its realization and construction if the environmental quality criteria are not fulfilled and included in the multi-criteria optimization model. At the same time, the most sustainable and environmentally friendly technical solutions, such as the renewable hydro pump storage scheme, cannot be realized without proper project management and investment.

The results and conclusions are valid for all the structures and projects of renewable resources, where there is a conflict to the environment. This research has implications to all decision-making processes focusing on holistic analyses of conflicted techno-economical and environmental parameters.

The value of the paper and research is in proving the necessity of simultaneous analyses of technical, economical and environmental impacts on the projects. All the results of the research are beneficial for stakeholders who intend to invest in renewable hydro energy resources, in the function of sustainable development.