An evaluation of microwave and RF technology as energy and time efficient alternatives for the drying process of barley malt

The objective of this project was to explore the fundamental interactions between microwave and radio frequency (RF) energy and malt. The main goal was to develop and apply a method for the reduction of time and energy costs and the enhancement of product quality in the kilning process which is used to dry malted barley. Volumetric heating technologies such as microwaves and radio frequency heating have been applied in industrial processing for many years and have the potential to reduce both time and energy costs compared with conventional heating. Potential benefits include savings in energy and process time whilst increasing product homogeneity and thus quality. Furthermore, it was important that the treatment should not adversely affect any of the key brewing (or distilling) quality parameters which are currently specified by the malt end-users. Firstly, the impact of moisture content on the dielectric properties of whole malt and barley grains (variety Tipple) at varying moisture contents relevant to the malting process (5-46% w/w) was investigated. Measurements were obtained using the transmission line waveguide technique, at room temperature (20°C) using microwave frequencies between 2.3 - 2.5 GHz. According to the results, water content was the dominant factor affecting the dielectric properties of both malt and barley grains and there was a strong similarity between malt and barley dielectric properties at a set moisture content, despite their different chemical compositions. The dielectric constant (ε´) of malt increased from 2.14 to 6.54 over the range of 5 to 46% w/w moisture, whereas for barley the equivalent range in ε´ was 2.21 to 6.72. The dielectric loss factor (ε˝) increased with moisture content for both malt and barley from 0.03 to 1.12 and from 0.03 to 1.03 respectively. The outcomes of this work could be applied to the development of microwave processing of malt and barley whole grains. Following the characterisation of these dielectric properties at microwave frequencies, it was decided that the penetration depth of microwaves in barley grains was unlikely to deliver sufficient throughput for an industrial process to be developed. Hence we opted next to investigate the application of radio frequencies (RF) to the drying of malt. We investigated the influence of radio frequency energy applied to malt hydrated to different moisture contents in comparison with a conventional drying process. At the end of the RF processing the moisture content was measured and the amylase activity of the bulk sample was tested. The high and medium loss samples did not maintain the required enzyme activity at the end of the drying process due to high sample temperature effects. In contrast, the low loss samples had better enzyme preservation, despite the fact that high temperatures (>90°C) still existed. This trend 4 could be explained by the fact that the time of the RF treatment in this experiment was less than that in the case of high and medium loss samples. Additional tests were performed to optimise the variable parameters of the RF tunnel system in order to achieve a smoother drying procedure for the malt. The observations from the RF tunnel experiments showed that more extensive study was required to control the temperature effect that was responsible for the deactivation of the amylases. Moreover an additional study on the effect of lower RF frequencies on the drying process of malt in combination with conventional drying could be more promising for the final product quality and for the decrease of time and energy costs

Electromagnetic heating for industrial kilning of malt: a feasibility study

Industrial malting operations use ~800kWh/t of energy to produce the heat required to kiln malt. Electromagnetic heating technologies are suggested as a way to potentially improve the energy efficiency of the kilning processing. In this work, the potential for using electromagnetic heating to dry malt to commercially acceptable moisture levels, whilst preserving the activity of enzymes critical for downstream brewing processes is investigated. The 2450 MHz bulk dielectric properties of malt at moisture contents consistent with those occurring at different points in the kilning process are evaluated; 12% is shown to be a critical moisture level below which drying becomes more energy intensive. Calculated penetration depths of electromagnetic energy in malt at radio frequency are 100 fold higher than at microwave frequencies, showing a significant advantage for commercial scale batch processing. The moisture contents and alpha and beta amylase activity of malt subjected to RF heating at different temperatures, treatment times and RF energy inputs in the intermediate and bound water drying regions were determined. It is shown for the first time that whilst significantly reduced process times are attainable, significant energy efficiency improvements compared to conventional kilning can only be achieved at higher product temperatures and thus at the expense of enzyme survival. It is suggested that RF heating may be feasible where higher bulk temperatures are not critical for downstream use of the material or when used in hybrid systems

Uncertainty in Natural Language Generation: From Theory to Applications

Recent advances of powerful Language Models have allowed Natural Language Generation (NLG) to emerge as an important technology that can not only perform traditional tasks like summarisation or translation, but also serve as a natural language interface to a variety of applications. As such, it is crucial that NLG systems are trustworthy and reliable, for example by indicating when they are likely to be wrong; and supporting multiple views, backgrounds and writing styles -- reflecting diverse human sub-populations. In this paper, we argue that a principled treatment of uncertainty can assist in creating systems and evaluation protocols better aligned with these goals. We first present the fundamental theory, frameworks and vocabulary required to represent uncertainty. We then characterise the main sources of uncertainty in NLG from a linguistic perspective, and propose a two-dimensional taxonomy that is more informative and faithful than the popular aleatoric/epistemic dichotomy. Finally, we move from theory to applications and highlight exciting research directions that exploit uncertainty to power decoding, controllable generation, self-assessment, selective answering, active learning and more

An evaluation of microwave and RF technology as energy and time efficient alternatives for the drying process of barley malt

The objective of this project was to explore the fundamental interactions between microwave and radio frequency (RF) energy and malt. The main goal was to develop and apply a method for the reduction of time and energy costs and the enhancement of product quality in the kilning process which is used to dry malted barley. Volumetric heating technologies such as microwaves and radio frequency heating have been applied in industrial processing for many years and have the potential to reduce both time and energy costs compared with conventional heating. Potential benefits include savings in energy and process time whilst increasing product homogeneity and thus quality. Furthermore, it was important that the treatment should not adversely affect any of the key brewing (or distilling) quality parameters which are currently specified by the malt end-users. Firstly, the impact of moisture content on the dielectric properties of whole malt and barley grains (variety Tipple) at varying moisture contents relevant to the malting process (5-46% w/w) was investigated. Measurements were obtained using the transmission line waveguide technique, at room temperature (20°C) using microwave frequencies between 2.3 - 2.5 GHz. According to the results, water content was the dominant factor affecting the dielectric properties of both malt and barley grains and there was a strong similarity between malt and barley dielectric properties at a set moisture content, despite their different chemical compositions. The dielectric constant (ε´) of malt increased from 2.14 to 6.54 over the range of 5 to 46% w/w moisture, whereas for barley the equivalent range in ε´ was 2.21 to 6.72. The dielectric loss factor (ε˝) increased with moisture content for both malt and barley from 0.03 to 1.12 and from 0.03 to 1.03 respectively. The outcomes of this work could be applied to the development of microwave processing of malt and barley whole grains. Following the characterisation of these dielectric properties at microwave frequencies, it was decided that the penetration depth of microwaves in barley grains was unlikely to deliver sufficient throughput for an industrial process to be developed. Hence we opted next to investigate the application of radio frequencies (RF) to the drying of malt. We investigated the influence of radio frequency energy applied to malt hydrated to different moisture contents in comparison with a conventional drying process. At the end of the RF processing the moisture content was measured and the amylase activity of the bulk sample was tested. The high and medium loss samples did not maintain the required enzyme activity at the end of the drying process due to high sample temperature effects. In contrast, the low loss samples had better enzyme preservation, despite the fact that high temperatures (>90°C) still existed. This trend 4 could be explained by the fact that the time of the RF treatment in this experiment was less than that in the case of high and medium loss samples. Additional tests were performed to optimise the variable parameters of the RF tunnel system in order to achieve a smoother drying procedure for the malt. The observations from the RF tunnel experiments showed that more extensive study was required to control the temperature effect that was responsible for the deactivation of the amylases. Moreover an additional study on the effect of lower RF frequencies on the drying process of malt in combination with conventional drying could be more promising for the final product quality and for the decrease of time and energy costs