Comparison of rheological properties of different materials

Within the scope of the task, the rheological properties of various polymeric materials (also food, such as tomato concentrate, mustard, honey, mayonnaise, etc.) will be determined and compared. Based on rheological tests and taste, the classification of the materials and proposition of a quality control procedure, i.e. design a simple test to determine the properties of the material, will be assessed.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Crystallization kinetics of polymer materials

The properties of polymer products are defined also by the properties of feedstock materials. Moreover, the properties of polymeric materials (especially partially crystalline thermoplastics) can be changed by changing the manufacturing parameters. One of the important parameters is the rate of cooling of the material in the mold, which affects the degree of crystallinity of the polymer.

The aim of the study is to determine the influence of cooling rate on the formation of crystalline structure of polymeric materials. The task involves using the DSC method to determine the degree of crystallization and the optical microscope for observing the crystallization process.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Design of transportation data logger

During transportation a product can experience unexpected dynamic loads in form of impacts, drops and external vibration. Although this sudden load can appear during transportation only on rare occasions it can lead to significant damage of the product if the certain threshold is exceeded. Within this diploma thesis it is expected to study possibilities for construction of transportation load logger with affordable components (accelerometer, AD converter, digital signal writer) and with low energy consumption such that it would be able to operate during complete transportation process without a need for external power supply.

Contact person: Prof. PhD. Janko Slavič

Webpage of the laboratory: http://www.ladisk.si/

High-temperature tribology – Evaluation of friction and wear

More and more applications nowadays operates at high temperatures and this arises also the important challenges in terms of tribological properties at these severe conditions. Within the scope of this work, the student will use Load-Scanner tribometer device, designed for testing the tribological properties of materials up to 800 °C. The work will include performing the tests, where load (contact pressure) and number of cycles will be changed at different temperatures in order to obtain general picture of the system, especially in terms at which conditions the significant wear of materials is obtained and how it can be evaluated (by measuring the wear volume or with gravimetric technique).

Contact person: Prof. PhD. Mitjan Kalin

Webpage of the laboratory: https://www.tint.fs.uni-lj.si/

Influence of 3D printed thermochromic polymers on mechanical properties

Thermochromism is subclass of chromogenic phenomena, where visible optical properties change dependence on temperature. This phenomenon could appear in thermoplastics, duroplastics, gels, inks or paints. Colour change of thermochromic materials could be reversible or irreversible. Thermochromic systems are widely used as a carrier in various applications such as smart packaging, security printing, toys and marketing. Thermochromic pigments and their incorporation into mass market polymers have become increasingly important in the art and textile application. With use of 3D printer, a variety of different products could be made. We will focus on use of PLA filaments with incorporated thermochromic pigment. The mechanical properties of both commercial and extruded thermochromic polymer will be investigated.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Influence of Manufacturing Parameters on Piezoresistive Properties of 3D Printed Structures

An interest for additive manufacturing or 3D printing is increasing in recent years, since geometries unattainable with classical manufacturing processes, may be produced. On the other hand, parts created by additive manufacturing exhibit anisotropic properties and are highly dependent on many process parameters. The behaviour of additively manufactured parts is difficult to predict as a result. The goal of the presented thesis is to study the influence of manufacturing process on the piezoresistive properties of product, produced by fused deposition modelling. To achieve this goal, the student has to gain the basic knowledge of fused deposition modelling, design of experiments and piezoresistivitiy at first. Afterwards, the obtained knowledge has to be used, to design a systematic approach, to extract the influential manufacturing parameters by an already existing experiment.

Contact person: Prof. PhD. Janko Slavič

Webpage of the laboratory: http://www.ladisk.si/

Measurement of the ZDDP tribofilm thickness using optical interferometer and atomic force microscope

Diamond-like carbon (DLC) coatings are very promising material for the use in many applications, in particular those operating under the most demanding boundary lubrication conditions, including automotive, where low friction and durability are of extreme importance. In order to introduce DLCs to automotive application, it is necessary that DLC coatings “synchronized” with conventional automotive lubricants where zinc dithiophosphates (ZDDPs) are key additives.

Numerous studies have focused on interactions between various DLCs and lubricants containing ZDDPs, however, the understanding of ZDDP-based lubrication of DLC is still far from understood.

Within this work the emphasis will be on the measurements of ZDDP tribofilm thickness, formed on the contacting surfaces of various DLC coatings (a-C:H and a-C:H:Si), after tribological tests performed under boundary lubrication conditions. The thickness measurement will be performed using two nano-technological tools, optical interferometer and atomic force microscope.

Contact person: Prof. PhD. Mitjan Kalin

Webpage of the laboratory: https://www.tint.fs.uni-lj.si/

Measurements of thermal properties of polymeric materials using a simple device

The aim of the study is to measure the melting temperature and crystallization of various thermoplastic materials using a simple device. Within the scope, the device will be designed and manufactured. The task includes: design and manufacture of the device, testing of different thermoplastic materials and comparison of results with results, obtained with DSC method.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Planar kinematics identification using image-based methods and open-source tools

Image-based displacement measurement methods have in recent years been established as a valid alternative to many conventional techniques in experimental mechanics. The author of this thesis will have an opportunity to perform measurements using one of the most capable commercially available high-speed cameras and get familiar with some of the available open-source tools for image-based displacement measurements in the Python ecosystem. The goal is to perform an analysis of the planar kinematics of a select mechanical system, focusing on a software implementation using existing open-source tools.

Contact person: Prof. PhD. Janko Slavič

Webpage of the laboratory: http://www.ladisk.si/

Rheological properties of multiply recycled HDPE material

The reuse of polymeric materials is important for sustainable development, where recycling plays an important role in reducing waste materials. Unfortunately, some of the properties of polymeric materials change during recycling process. The aim of the study is to determine how the rheological properties of high-density polyethylene (HDPE), which are associated with processing properties, change with repeated recycling.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Surface energy – Effect of surface preparation

Surface energy is relevant property of surfaces, since it defines the interaction of surface with surroundings, other surfaces, liquids, etc. In general the surface energy defines the chemistry of surface, and common approach to determine it is in-direct. Namely, contact angles measurements by employing different models is used. Since contact angle measurements are effected not only by surface chemistry itself, but also by other effects, such as environment, surface preparation/cleaning, surface roughness, this can significantly effect on measured values and thus on calculated surface energies. In this work student will prepare surfaces with different roughness and vary environment conditions and surface preparation (cleaning). The goal is to determine which of previously mentioned effects are relevant and should be paid more attention when determining the surface energy.

Contact person: Prof. PhD. Mitjan Kalin

Webpage of the laboratory: https://www.tint.fs.uni-lj.si/

Thermal properties of multiply recycled HDPE material

The reuse of polymeric materials is important for sustainable development, where recycling plays an important role in reducing waste materials. Unfortunately, some of the properties of polymeric materials change during recycling process. The aim of the study is to determine (i) how the thermal properties of high-density polyethylene (HDPE) are changed by repeated recycling and (ii) when using recycled materials in the production process is it necessary to adjust the manufacturing parameters.

Contact person: Assist. Prof. PhD. Lidija Slemenik Perše

Webpage of the laboratory: http://web.fs.uni-lj.si/cem/sl/domov/

Topological optimization of the dynamic properties of the selected product

The aim is to acquire the knowledge of structure analysis using the topological optimization. For this purpose, it is first necessary to examine the existing state of the field, after which the topology optimization within the ANSYS software environment is performed on the selected product.

Contact person: Prof. PhD. Janko Slavič

Webpage of the laboratory: http://www.ladisk.si/