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Nirmal Prashanth Maria Joseph (니르말 프라샤츠 마리아 조세프라),Nagamalleswara Rao Alluri(올루리 나가마레스와라 라오),Abisegapriyan K.S(아비세가프리얀 K.S),Sang Jae Kim(김상재) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
The barium titanate system was analyzed to improve the electrical properties through the effect of sintering and dopant substitution. The barium titanate was modified with various dopants and prepared six different compositions, and the optimized composition was analyzed with four different sintering conditions towards high electrical properties. The synthesized material XRD pattern and Raman spectrum confirm that it formed as morphotropic phase boundary with dual-phase. The morphological and elemental analyses were confirmed the random shape particles with all the elements present in the stoichiometric ratio. The material's dielectric and ferroelectric properties were analyzed. The measured maximum piezoelectric coefficient d<sub>33</sub> was 260 pC/N for the optimized 0.3Ba<sub>0.7</sub>Ca<sub>0.3</sub>TiO<sub>3</sub>-0.7BaSn<sub>0.12</sub>Ti<sub>0.88</sub>O<sub>3</sub> system. The finalized system used in the fabrication of piezoelectric nanogenerator for biomechanical motion energy conversion. The energy harvester device was fabricated in a cost-effective process. Its eco-friendly nature and the biomechanical energy conversion will partially help solve the energy crisis and the development of battery-free sensors.
Maria Joseph Raj, Nirmal Prashanth,Alluri, Nagamalleswara Rao,Vivekananthan, Venkateswaran,Chandrasekhar, Arunkumar,Khandelwal, Gaurav,Kim, Sang-Jae Elsevier 2018 APPLIED ENERGY Vol.228 No.-
<P><B>Abstract</B></P> <P>A cost-effective layer-by-layer brush-coating technique was developed to fabricate a flexible yarn-based piezoelectric nanogenerator (FY-PNG) to harness abundant waste mechanical energy. A simple sol-gel method was used to synthesize the orthorhombic crystalline phase of bismuth titanate perovskite, i.e., Bi<SUB>4</SUB>Ti<SUB>3</SUB>O<SUB>12</SUB> (BiTO). A single FY-PNG device generated a maximum peak-to-peak open-circuit voltage (V<SUB>OC(P–P)</SUB>), short-circuit current (I<SUB>SC(P–P)</SUB>), and instantaneous area power density of 60 V, 400 nA, and 18.5 mW/m<SUP>2</SUP>, respectively, upon application of a 1 N periodic mechanical load. The switching polarity of the FY-PNG demonstrated good phase shifting between the output signals and confirmed that the output derived from the device and not from any external sources. The working mechanism, electrical poling effect, force analysis, repeatability, stability, charging, energy storage analysis, and sensitivity to biomechanical force of the FY-PNG was thoroughly investigated. The FY-PNG device output was used to power five commercial green light-emitting diodes (LEDs) and a display system. Additionally, a non-invasive self-powered breathing sensor (SPBS) was developed to monitor human inhalation/exhalation. The repeatability and reproducibility of SPBS evaluated using different devices and test subjects demonstrated a good variation in output (i.e., 0.2–0.4 V) for inhalation/exhalation; the SPBS was also evaluated under slow/fast and constant breathing conditions. The proposed brush-coating technique for FY-PNGs is an efficient, cost-effective, eco-friendly, and easily scalable technique that can pave the way to the design of novel-shaped PNG devices for applications such as implantable self-powered biosensors and automotive electronic systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cost-effective brush coating technique employed to coat all layers of nanogenerator. </LI> <LI> Flexible Yarn-piezoelectric nanogenerator has dual functionality-harvesting/sensing. </LI> <LI> Self-powered breath sensor has good repeatability/stability with test subjects. </LI> <LI> Proposed nanogenerator is suitable to harness linear/nonlinear surface motions. </LI> <LI> Fabrication process is eco-friendly, less time consuming, and high reproducibility. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Self-propelled Adaptive Electrophoretic Drug Diffusion Device Using Piezoelectric Gradient
Abisegapriyan KS(K.S. 아비세가프리얀),Nirmal Prashanth Maria Joseph (니르말 프라샨스 마리아 조셉 라즈),Sang-Jae Kim(김상재) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4
A piezoelectric-driven electroporation system is developed for transdermal drug delivery with an adaptive diffusion rate for improved patient comfort and compliance. A miniaturized in-situ piezo-electrophoretic membrane was designed to trigger the electro-responsive drug carrier and activate the electrophoretic treatment for enhanced drug delivery efficiency through biomechanical motion. In this system, a flexible transdermal patch, with a bio-inspired integration of Agarose-BNKT based permeable membrane, was adopted to ensure stable drug diffusion due to an applied pressure gradient. The integrated system efficiently releases a drug dosage of 5 μg/cm<sup>2</sup> per minute by tapping over the patch. Furthermore, the system has achieved an adaptable drug release rate from 0.15 to 0.35 μg/cm<sup>2</sup> per minute by varying the finger winding (bending angle of the patch). Our results demonstrate that the proposed system is intended to provide patients with an easy approach to achieve a customized rate and dosage of drug release and expanding the applications of biocompatible piezo-materials and devices.