Vibration energy harvesters are especially interesting to use in an environment where there is one dominant vibration frequency present because then the harvesters can be designed to resonate at that specific frequency. To spread out the power yield over more frequencies a multi-modal harvester can be used which can resonate at multiple frequencies. A vibration with more than one sine wave can be manifested in a number of ways. The two frequencies can be present simultaneously, or they can alternate each other. How the energy harvesters react to these different vibration inputs is researched in this paper. Two fundamentally different multi-modal energy harvesters are used here. One which can be described by a coupled system of equations and one uncoupled. Two prototypes of an uncoupled and one coupled device are made and tested on an electromagnetic shaker. The vibration signals are sent to the shaker and the power output of the energy harvesters is measured using piezoelectric transducers mounted to the mechanisms. The results show that a phaseshift in the sine wave input signal generally results in a increase in power, where a decrease was assumed beforehand. When switching the input vibration from the first to the second eigenfrequency the power output does drop significantly, but the coupled mechanism has a substantially higher power output than the uncoupled device. And when the mechanisms are excited by a vibration with two eigenfrequencies at the same time no significant difference between the two can be observed, nor does the power output drop significantly. While the comparison between these two mechanisms is probably accurate, the quantitative conclusions must be taken with a grain of salt as it was noticed in a later stage of the research that the vibration signals were not consistent over the entire time period. At this point it is unclear if an overall better mechanism can be picked between the coupled and uncoupled one. However, it is shown that both have their distinct advantages where they outperform their counterpart, which can be used for designing a better energy harvester in future applications

Background The clinical stage of non-small cell lung cancer (NSCLC) determines the initial treatment, whereas the pathologic stage best determines prognosis and the need for adjuvant treatment. In an era in which stereotactic ablative radiotherapy (SABR) has become an alternative modality to surgical intervention, clinical staging is even more important, because pathologic staging is omitted in the case of SABR. The objective of this study was to determine the concordance between clinical and pathologic stage in routine clinical practice for patients with early-stage NSCLC. Methods Prospective data were derived from the Dutch Lung Surgery Audit (DLSA) in 2013 and 2014. Patients with clinical stage I NSCLC who underwent surgical resection and had a positron emission tomography-computed tomography (PET-CT) scan in their clinical workup were selected. Clinical and pathologic TNM (cTNM and pTNM) stages were compared. Results From a total of 1,790 patients with clinical stage I, 1,555 (87%) patients were included in this analysis. Concordance between cTNM and pTNM was 59.9%. Of the patients with clinical stage I, 22.6% were upstaged to pathologic stage II or higher. In total, 14.9% of all patients with clinical stage I had nodal metastases, and 5.5% of all patients had unforeseen N2 disease. In patients with clinical stage T2a tumors, 21.3% had nodal metastases, 14.5% being N1 and 6.7% being N2 disease. Conclusions Concordance between clinical and pathologic stage is 59.9%. In patients with clinical stage I NSCLC, 22.6% were upstaged to pathologic stage II or higher, which is an indication for adjuvant chemotherapy. Improvement in accuracy of staging is thus needed, particularly for these patients.@en