In this study we used the near-field electrospinning (NFES) process with the metallic coaxial needle injector to fabricate piezoelectric poly(vinylidene fluoride) (PVDF) hollow fiber tubes. Using these tubes, we designed an energy capture device featuring parallel electrodes to harvest low-frequency energy. We examined the effects of several parameters on the properties of the piezoelectric PVDF fiber tubes (PPTs), including the core flow rate, shell flow rate, concentration of PVDF, rotating tangential speed, and electric field. The elongation of the PPTs was greater than that of solid PVDF fibers, with the tensile strength of the PPTs reaching 32.49 MPa (as determined through a micro-tensile measurement). The output voltage of the PPTs was considerably higher (71.66 mV) and, with an external load resistance of 6 MΩ, the output power was also significantly greater (856.07 pW), which is higher than the solid PVDF fiber (output voltage = 45. 66 mV and the maximum output power = 347.61 pW). As a result, the power generation of the PPTs was 2.46 times higher than that of the solid fibers. Thus, the PPTs not only displayed mechanical stiffness but also produced a greater power output.

A flexible PVDF/PMLG energy harvester captures electromechanical energy and its energy conversion efficiency was up to three times higher than individual PVDF and PMLG.

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One of the most common means for diagnosis is through medical laboratory testing, which primarily uses venous blood as a sample. This requires an invasive method by cannulation that needs proper vein selection. The use of a vein finder would help the phlebotomist to easily locate the vein, preventing possible pre-analytical error in the specimen collection and even more discomfort and pain to the patient. This paper is a review of the scientific publications on the different developed low-cost vein finder prototypes utilizing camera assisted near infrared (NIR) light technology. Methods: Electronic databases were searched online, these included PubMed (PMC), MEDLINE, Science Direct, ResearchGate, and Institute of Electrical and Electronics Engineers (IEEE) Xplore digital library. Specifically, publications with the terms vein finder prototype, NIR technology, vein detection, and infrared imaging were screened. In addition, reference lists were used to further review related publications. Results: Cannulation challenges medical practitioners because of the different factors that can be reduced by the utilization of a vein finder. A limited number of publications regarding the assessment of personnel performing cannulation were observed. Moreover, variations in methodology, number of patients, type of patients according to their demographics and materials used in the assessment of the developed prototypes were noted. Some studies were limited with regard to the actual human testing of the prototype. Conclusions: The development of a low-cost effective near infrared (NIR) vein finder remains in the phase of improvement. Since, it is being challenged by different human factors, increasing the number of parameters and participants/human for actual testing of the prototypes must also be taken into consideration for possible commercialization. Finally, it was noted that publications regarding the assessment of the performance of phlebotomists using vein finders were limited.