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Investigation of residual stresses in polypropylene using hot plate welding
(2020-08-05)
During the cooling process of the molten material, residual stresses appear because the reduced volume of the cooled material cannot fully fill the space formerly occupied by the molten material. The morphology in and around the weld is formed by different factors depending on the material and process parameters. Different morphological structures relate to different mechanical properties. The process parameters and the welding results including morphology and residual stress are linked together. In this article, ...
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Optimal Energy Supply Structures for Industrial Sites in Different Countries Considering Energy Transitions: A Cheese Factory Case Study
(2016)
This present study focuses on analysing the most efficient utility energy supply structure in terms of primary energy efficiency, carbon emissions and energy costs. In the German dairy industry, separate conversion with gas fired steam boiler, and cooling with ammonia chillers are the-state-of-the-art technologies. It is attractive due to its robustness and low investment costs. But given the ongoing energy transition to renewable energy, opportunities to reduce emissions will become increasingly important. There are ...
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Dimensioning of Heat Pump Systems Based on Pinch Analysis and Energy Monitoring Data
(2018)
In this paper, typical process chains of metal processing/gear manufacturing are examined according to the pinch method with regard to their potential for heat recovery and their suitability for heat pump applications. The focus is on machine tools and parts washing machines as fluctuating heat sources and sinks. Heat sources at a low temperature level, such as the cooling of machine tools, are becoming increasingly important in contrast to conventional fossil waste heat sources due to the electrification of energy ...
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Evaluation of a Stratified Tank based Heat Recovery Loop via Dynamic Simulation
(2018)
Prerequisite for hot water recovery in the dairy and beverage industry is the use of heat storage, such as stratified tanks. Total Site Heat Integration enables the targeting of heat recovery potential, the concrete identification of suitable sinks and source profiles and the dimensioning of intermediate circuits and storages. For a cost and energy efficient storage, the aim to maintain stratification by suitable thermocline control management. Dynamic simulation enables a reliable estimation of energy savings and ...
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Influence of the degree of crystallinity and the surface free energy on the adhesion properties of different PLA/PBS blends in multicomponent injection molding
(2020-01-10)
Biocomposites made of biodegradable polymers have grown in interest due to their environmentally friendliness, considering that non-biodegradable polymers waste conduces to pollution, displaying high environmental impact in climatic changes. Therefore, in the presented study, biodegradable Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) were investigated as a series of PLA/PBS melt-blending compounds with the weight ratios of 50/50, 60/40, 70/30, 80/20 and 90/10. In a two-component injection molding ...
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Relaxation properties of polyoxymethylene and ethylene–octene copolymer blend in solid and melt states
(2012-08-30)
Rheological properties of polyoxymethylene (POM) and ethylene–octene copolymer (EOC) in solid and melt states were investigated. Blends were prepared with a twin screw extruder at broad component wt-to-wt ratios (10, 30, 50, 70, 90 wt% of EOC). The morphology as well as calorimetric, rheological, and elastic properties of the blends were studied. The investigation showed that POM/EOC blends were heterogeneous in nature and had a broad phase transition region between 30 and 70 wt% of POM. Because during processing ...
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Predictive Simulation-based Optimisation of Cooling System Including a Sprinkler Tank
(2018)
Prerequisite for an efficient cooling energy system is the knowledge and the optimal combination of different operating conditions of individual compression and free cooling chillers. The performance of cooling systems depends on its part load performance and its condensing temperature, which are often unknown. Recorded energy data remains unused and manufacturers' data significantly differs from the real performance. For this purpose, manufacturer and real data are combined and continuously adapted to form partial ...
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Mechanical properties of hybrid glass/kenaf fibre-reinforced epoxy composite with matrix modification using liquid epoxidised natural rubber
(2015-04-27)
The hybridisation of natural fibre with glass fibre provides a method to improve the mechanical properties instead of using the natural fibres alone. This research is focused on the hybridisation of glass/kenaf fibre with the addition of liquid epoxidised natural rubber to enhance the desired mechanical properties of the composite by reducing the synthetic fibre usage and encourage the natural fibre consumption. Liquid epoxidised natural rubber was added to the epoxy matrix in order to improve its mechanical properties ...
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Parameter identification for constitutive models of innovative textile composite materials using digital image correlation
(2019-11-18)
This contribution focuses on an innovative composite material consisting of textile layers made from continuous wooden fibers embedded in a thermoplastic matrix. A finite element simulation of potential use‐cases is planned to support the development process and to study the suitability of the material in an architectural context. The simulation is based on a constitutive model assuming homogenous orthotropic elastic behavior and will be expanded to include multiscale modeling in future research. The material parameters ...