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Aufsatz
Process and utility systems integration and optimisation for ultra-low energy milk powder production
(2017-04-26)
This study applies a Total Site Heat Integration approach in conjunction with a detailed process and utility model, to develop an innovative ultra-low energy milk powder plant design. The basis for the analysis is a state-of-the-art modern milk powder plant that requires 5265 MJ/tp of fuel and 210.5 kWh/tp (58.5 MJe/tp) of electricity. The model of the modern milk powder plant was validated against industrial data and changes to process and/or utility systems are targeted and implemented into the model to understand ...
Aufsatz
Automatic Time Series Segmentation as the Basis for Unsupervised, Non-Intrusive Load Monitoring of Machine Tools
(2019)
Detailed energy monitoring and benchmarking at the individual component level is necessary to increase energy efficiency in complex production systems. Non-intrusive load monitoring (NILM) provides an economical solution for operational state detection and load disaggregation without the need for large-scale use of fine-grained energy meters. Existing supervised NILM approaches require detailed training data including control information about individual devices. Unsupervised approaches, on the other hand, often ...
Aufsatz
Total Site Utility Systems Optimisation for Milk Powder Production
(2016)
This study applies the Total Site Heat Integration method, in conjunction with a detailed process and utility model, to investigate three methods to increase the energy efficiency of the utility supply system for milk powder production. Sequentially explored opportunities are: (1) increasing boiler efficiency through condensing economisers, (2) waste heat recovery from the chiller unit, and (3) Combined Heat and Power (CHP) for electricity production. The basis for the analysis is the anticipated future milk powder ...
Aufsatz
Numerical Two-Scale Simulations of Damage Evolution at Refractory Materials
(2014-02-25)
Fracture and damage processes on micro- and mesoscale are combined with macroscale simulations applying numerical multiscale approaches. Cracks and grain boundaries are reproduced in cell models that take account of transand intercrystalline crack growth. The global, in general thermomechanical boundary value problem is considered within a continuum mechanics framework. Two approaches are presented combining the scales. Simple processes on the smaller level are described in analytical models including the damage ...
Aufsatz
Sensor Concept Based on Piezoelectric PVDF Films for the Structural Health Monitoring of Fatigue Crack Growth
(2011)
A new sensor concept for monitoring fatigue crack growth in technical structures is presented. It allows the in-situ determination of the position of the crack tip as well as the fracture mechanical quantities. The required data are obtained from a piezoelectric polymer film, which is attached to the surface of the monitored structure. The stress intensity factors and the crack tip position are calculated from electrical potentials obtained from a sensor array by solving the non-linear inverse problem.
Aufsatz
Crack path predictions and experiments in plane structures considering anisotropic properties and material interfaces
(2015-09-28)
In many engineering applications special requirements are directed to a material's fracture behavior and the prediction of crack paths. Especially if the material exhibits anisotropic elastic properties or fracture toughnesses, e.g. in textured or composite materials, the simulation of crack paths is challenging. Here, the
application of path independent interaction integrals (I-integrals), J-, L- and M-integrals is beneficial for an accurate crack tip loading analysis.
Numerical tools for the calculation of loading ...
Aufsatz
Microscale-Motivated Continuum Damage Simulations of Brittle Ceramics under Thermomechanical Loading
(2016-05-02)
Two approaches towards modeling damage in a brittle material caused by thermomechanical loading are presented.
Bothrelyonmicrocrack growth, in the first case in ahomogeneousmatrix, in the second one at grain boundaries.Two-scale simulations e.g. of thermal shocks applied to single-phase or layered structures are performed in connection with the finite element method. Damage and crack patterns are predicted just as quantities like residual strength or critical temperature jumps.
Aufsatz
On the track of human errors - Procedure and results of an innovative assembly planning method
(2018-03-07)
Manual assembly operations are the endmost place of the production process and with it represent a melting pot for organizational, time-related and qualitative errors of manufacturing. Because competitive advantages are increasingly determined in the manual assembly, the creation of economical and reliable work steps is of fundamental importance for future business success. For that reason, at the institute of the authors, a procedure has been developed to use the knowledge of the Expert System for Task Taxonomy that ...
Aufsatz
Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures
(2017-08-25)
The physical properties of polycrystalline materials depend on their microstructure, which is the nano- to centimeter scale arrangement of phases and defects in their interior. Such microstructure depends on the shape, crystallographic phase and orientation, and interfacing of the grains constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF ...
Aufsatz
Assessment of probabilistic distributed factors influencing renewable energy supply for hotels using Monte-Carlo methods
(2017-04-05)
This paper investigates the use of renewable energies to supply hotels in island regions. The aim is to evaluate the effect of weather and occupancy fluctuations on the sensitivity of investment criteria. The sensitivity of the chosen energy system is examined using a Monte Carlo simulation considering stochastic weather data, occupancy rates and energy needs. For this purpose, algorithms based on measured data are developed and applied to a case study on the Canary Islands.
The results underline that electricity ...