<p>Lyophilization is the process of controllably removing the water
content from a material with the objective of increasing its stability and,
hence, its shelf life. This dissertation addresses two of the challenges faced
by lyophilization, namely continuous temperature-monitoring and lengthy primary
drying step.</p>
<p>Continuous
temperature monitoring of the product is imperative to a successful lyophilization
process. It is more efficient to employ wireless temperature sensors rather
than the conventional thermocouples. These wireless sensors need to keep a low
profile that does not allow bulky battery attachment. Therefore, harvesting
microwave energy is an excellent practice to power these sensors. Energy
harvesting problem is twofold. One, designing an efficient flexible
power-harvester (rectenna). To address this problem, we present a flexible
rectenna with superior efficiency. While doing so, we establish the design
procedure that can be followed for similar designs. Two, delivering sufficient
power to the rectenna location inside the chamber. To address this problem, we
propose two electromagnetic techniques, namely the statistical electromagnetics
(SEM) and the electromagnetic time reversal (EMTR). These enable uniform power
distribution and higher total efficiency.</p>
As for the lengthy primary
drying, to speed up the process, we propose RF-heating as a replacement for
conventional heating. We establish a procedure for frequency selection based on
the material under lyophilization and the geometrical properties of the
freeze-drier’s chamber. The same techniques, SEM and EMTR are used. We conduct RF-assisted
lyophilization processes based on SEM on different pharmaceutical bare
excipients and on Myoglobin in four different excipients. The results confirm
the superiority of the proposed technique in terms of drying time and heating
uniformity.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/11323046 |
| Date | 31 January 2022 |
| Creators | Ahmed Mahmoud Mahrous Abdelraheem (8085602) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY-NC-SA 4.0 |
| Relation | https://figshare.com/articles/thesis/Electromagnetic_Techniques_for_Performance_Enhancement_of_Wireless_Systems/11323046 |
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