Abstract

Dielectric properties of any particular material will determine the level of microwave (MW) heating. Therefore, measurement of the dielectric properties of MW treatment subject materials is necessary. This study investigated the dielectric properties of six roughages and three concentrate animal feeds across the microwave frequency range of 1 × 10⁹ to 5 × 10⁹ Hz. Six treatment groups, named control (at equilibrium moisture constant), oven dried (0% moisture), 25% moisture added, 50% moisture added, 75% moisture added, and 100% moisture added groups were prepared for the study. Three separate replications and five observations for each replication were used to assess the dielectric properties of these materials. The results showed that for increasing moisture content, from oven-dried, though the control status, to 100% added moisture, both the dielectric constant (real part) and the dielectric loss factor (imaginary part) increased for both the roughages and concentrates. However, the responses were not linear. The oven-dried plant samples' dielectric properties were very low compared with those of the higher moisture content samples. Thus, the sample's moisture content was the dominant contributor to the feed samples' dielectric behavior. Among all the feed samples, faba bean and wheat grain showed the highest response to added moisture. Mathematical models were developed to explain the dielectric properties of feeds as a function of frequency and moisture content. The goodness of fit (r²) for these models' real part varied between 0.85–0.99 for roughage and 0.98–0.99 for concentrate feed type. On the other hand, the goodness of fit for the imaginary part varied between 0.59–0.78 for roughage, and 0.81–0.93 for concentrate feeds.

摘要

任何特定材料的介电特性将决定微波 (MW) 加热的水平。因此，必须测量MW处理对象材料的介电特性。本研究在 1 × 10 ⁹至 5 × 10 ⁹的微波频率范围内研究了六种粗饲料和三种浓缩动物饲料的介电特性 赫兹。为研究准备了六个处理组，称为对照（在平衡水分常数下）、烘箱干燥（0% 水分）、添加 25% 水分、添加 50% 水分、添加 75% 水分和 100% 水分添加组。三个单独的重复和每个重复的五个观察被用来评估这些材料的介电特性。结果表明，为了增加水分含量，从烘箱干燥到 100% 添加水分，粗饲料和精矿的介电常数（实部）和介电损耗因子（虚部）均增加。然而，反应不是线性的。与水分含量较高的样品相比，烘干的植物样品的介电性能非常低。因此，样本' 水分含量是饲料样品介电行为的主要贡献者。在所有饲料样品中，蚕豆和小麦籽粒对添加水分的反应最高。开发了数学模型来解释作为频率和水分含量的函数的饲料的介电特性。拟合优度 (r² ) 对于这些模型的真实部分，粗饲料在 0.85-0.99 和精饲料类型的 0.98-0.99 之间变化。另一方面，虚部的拟合优度在粗饲料的 0.59-0.78 和精饲料的 0.81-0.93 之间变化。