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• Vibration Measurement of a Screening Machine

  116-123

  László Rónai

  József Lénárt

  Tamás Szabó

  Views:

  135

  In this paper we use linear vibration approach to make a model of a horizontal vibration screen, which can be applied at gravel pit in order to perform separation operation of the wet gravel particles. The model can produce the natural frequencies of the system, which are useful in the adjustment of the angular velocity of the vibration exciter. A laser triangulation unit is well applicable to measure peak-to-peak amplitude of the working vibration screen. Comparison has been performed between the results of the simulation and the measurements.

• Synthesis of Polylactic Acid (PLA) by Polycondensation Method

  286-293

  Tibor Horváth

  Tamás József Szabó

  Kálmán Marossy

  Views:

  292

  The Polylactic acid (PLA) is compostable and natural renewable sourced plastic type. Its mechanical properties quite similar to the PET, therefore the PLA is a good alternative for strongly ruled food industrial application. The PLA only has one critical attribute – the relatively low glass transition temperature. According to the relevant literature the glass transition of PLA is in the range of 40-70°C. In light of this fact, this material can be used only in that segments of food industrial field where the packaging process temperature are under of the lower limit of Tg range. The actual Tg of a material is highly depends on the molar mass and material structure, therefore the molar mass and the structure of material should be designed according to the future requirements of application and procedures.

• Polylactic Acid as a Potential Alternatives of Traditional Plastic Packagings in Food Industry

  123-129

  Tibor Horváth

  Tamás József Szabó

  Kálmán Marossy

  Views:

  316

  Huge quantity of synthetic polymers is used as packaging materials in different fields of food industries. A significant part of these polymers applied as a primary, direct food contact construction. The scoped application area is the sweet industry. In this field Polystyrol (PS), Polypropylene (PP) and Polyethylene terephthalate (PET) have used but during the last fifteen years the usage of PET has been grown. In one hand the price of this material is efficient, form other hand the PET is the one of the most safe (for food industrial applications) petrol chemical plastic that can be used as primary or secondary food contact packaging material. To maximize the customer safety and minimize the environmental impact of traditional PET, a new bio-sourced and bio-degradable alternative polymer aimed to be used in this special food industrial segment. One of the potential alternatives is the Polylactic acid (PLA) that would be a possible substitute as it is compostable and produced from renewable sources and has good physical and mechanical properties [1].

• Development of a Low-cost Pressure Sensor

  33-38

  László Rónai

  József Lénárt

  Tamás Szabó

  Views:

  204

  In this paper development of a pressure sensor has been discussed. The main benefit of this sensor is relatively cheap compared to commercially available ones. The unit contains a beam type load cell and a pneumatic cylinder. The load cell has 4 strain gauges in Wheatstone bridge configuration in order to convert the change of resistance into measurable voltage. The system is well applicable in numerous circumstances, where digital pressure signal is necessary for control or data acquisition.