Freeze casting of lamellar-structured porous lead-free (Na0.52K0.48)(Nb0.95Sb0.05)O3 piezoceramic with remarkable enhancement in piezoelectric voltage constant and hydrostatic figure of merit

2021 ◽  
Vol 32 (5) ◽  
pp. 5393-5403
Author(s):  
Prashant Dixit ◽  
Shaurya Seth ◽  
Bhupender Rawal ◽  
B. Praveen Kumar ◽  
Himanshu Sekhar Panda
Keyword(s):  
Figure Of Merit ◽  
Lead Free ◽  
Freeze Casting ◽  
Piezoelectric Voltage

Niobate-based lead-free piezoceramics: a diffused phase transition boundary leading to temperature-insensitive high piezoelectric voltage coefficients

2018 ◽  
Vol 6 (5) ◽  
pp. 1116-1125 ◽  
Author(s):  
Qing Liu ◽  
Jing-Feng Li ◽  
Lei Zhao ◽  
Yichi Zhang ◽  
Jing Gao ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Stability ◽  
Lead Free ◽  
Thermally Stable ◽  
Transition Boundary ◽  
Diffused Phase Transition ◽  
Piezoelectric Voltage ◽  
Phase Transition Boundary

A large and thermally stable d33 was observed in dense and translucent KNN-based ceramics. Forming the R–O–T diffused phase transition is validated as a feasible way to realize the simultaneous enhancement of piezoelectricity and thermal stability.

Piezoelectric Voltage Constant and Sensitivity Enhancements Through Phase Boundary Structure Control of Lead-free (K,Na)NbO3-based ceramics

2021 ◽  
Author(s):  
Min-Ku Lee ◽  
Byung-Hoon Kim ◽  
Gyoung-Ja Lee
Keyword(s):  
Material Parameter ◽  
Perovskite Oxide ◽  
Lead Free ◽  
Boundary Structure ◽  
Voltage Sensitivity ◽  
Phase Boundaries ◽  
Accelerometer Sensor ◽  
Structure Control ◽  
Piezoelectric Charge ◽  
Piezoelectric Voltage

Abstract The piezoelectric voltage constant (g33) is a material parameter critical to piezoelectric voltage-type sensors for detecting vibrations or strains. Here, we report a lead-free (K,Na)NbO3 (KNN)-based piezoelectric accelerometer with voltage sensitivity enhanced by taking advantage of a high g33. To achieve a high g33, the magnitudes of piezoelectric charge constant d33 and dielectric permittivity er of KNN were best coupled by manipulating the intrinsic polymorphic phase boundaries effectively with the help of Bi-based perovskite oxide additives. For the KNN composition that derives benefit from the combination of er and d33, the value of g33 was found to be 46.9 ´ 10-3 V·m/N, which is significantly higher than those (20 - 30 ´ 10−3 V·m/N) found in well-known polycrystalline lead-based ceramics including commercial Pb(Zr,Ti)O3 (PZT). Finally, the accelerometer sensor prototype built using the modified KNN composition demonstrated higher voltage sensitivity (183 mV/g) when measuring vibrations, showing a 29% increase against the PZT-based sensor (142 mV/g).

Lead-Free Thermoelectrics: High Figure of Merit in p-type AgSnmSbTem+2

2011 ◽  
Vol 2 (1) ◽  
pp. 157-161 ◽  
Author(s):  
Mi-Kyung Han ◽  
John Androulakis ◽  
Sung-Jin Kim ◽  
Mercouri G. Kanatzidis
Keyword(s):  
Figure Of Merit ◽  
Lead Free ◽  
High Figure ◽  
P Type

scholarly journals Enhanced Pyroelectric Performance of Lead-Free Zn-Doped Na1/2Bi1/2TiO3-BaTiO3 Ceramics

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 87
Author(s):  
Satyanarayan Patel ◽  
Kodumudi Venkataraman Lalitha ◽  
Nishchay Saurabh
Keyword(s):  
Figure Of Merit ◽  
Room Temperature ◽  
Temperature Stability ◽  
Mechanical Quality Factor ◽  
Lead Free ◽  
Figures Of Merit ◽  
Undoped Material ◽  
Threefold Increase ◽  
Mechanical Quality ◽  
Independent Behavior

Lead-free Na1/2Bi1/2TiO3-BaTiO3 (NBT-BT) has gained revived interest due to its exceptionally good high power properties in comparison to commercial lead-based piezoelectrics. Recently, Zn-modified NBT-BT-based materials as solid solution and composites have been reported to exhibit enhanced depolarization temperatures and a high mechanical quality factor. In this work, the pyroelectric properties of Zn-doped NBT-6mole%BT and NBT-9mole%BT ceramics are investigated. The doped compositions of NBT-6BT and NBT-9BT feature a relatively stable pyroelectric property in a wide temperature range of ~37 K (300–330 K) and 80 K (300–380 K), respectively. A threefold increase in detector figure of merit is noted for 0.01 mole Zn-doped NBT-6mole% BT at room temperature in comparison to undoped NBT-6mole%BT and this increase is higher than those of major lead-free materials. A broad range of the temperature-independent behavior for the figures of merit was noted (303–380 K) for Zn-doped NBT-6mole% BT, which is 30 K higher than the undoped material. The large pyroelectric figures of merit and good temperature stability renders Zn-doped NBT-BT an ideal candidate for pyroelectric detector and energy harvesting applications.

High Piezoelectric Voltage Coefficient in Structured Lead-Free (K,Na,Li)NbO3Particulate-Epoxy Composites

2016 ◽  
Vol 99 (12) ◽  
pp. 3957-3963 ◽  
Author(s):  
Nijesh K. James ◽  
Daniella B. Deutz ◽  
Ranjita K. Bose ◽  
Sybrand van der Zwaag ◽  
Pim Groen
Keyword(s):  
Lead Free ◽  
Epoxy Composites ◽  
Voltage Coefficient ◽  
Piezoelectric Voltage

Seti Figure of Merit

1997 ◽  
Vol 161 ◽  
pp. 711-717 ◽  
Author(s):  
John W. Dreher ◽  
D. Kent Cullers
Keyword(s):  
Figure Of Merit ◽  
Qualitative Difference ◽  
Current Generation ◽  
Detection Range ◽  
Sky Surveys ◽  
Independent Observations ◽  
Good For

AbstractWe develop a figure of merit for SETI observations which is anexplicitfunction of the EIRP of the transmitters, which allows us to treat sky surveys and targeted searches on the same footing. For each EIRP, we calculate the product of terms measuring the number of stars within detection range, the range of frequencies searched, and the number of independent observations for each star. For a given set of SETI observations, the result is a graph of merit versus transmitter EIRP. We apply this technique to several completed and ongoing SETI programs. The results provide a quantitative confirmation of the expected qualitative difference between sky surveys and targeted searches: the Project Phoenix targeted search is good for finding transmitters in the 109to 1014W range, while the sky surveys do their best at higher powers. Current generation optical SETI is not yet competitive with microwave SETI.

The Measurement of Performance in Probabilistic Diagnosis IV. Utility Considerations in Therapeutics and Prognostics

1981 ◽  
Vol 20 (02) ◽  
pp. 80-96 ◽  
Author(s):  
J. D. F. Habbema ◽  
J. Hilden
Keyword(s):  
Decision Theory ◽  
Figure Of Merit ◽  
Acute Abdominal Pain ◽  
Theory Approach ◽  
Expected Loss ◽  
Patient Benefit ◽  
Evaluation Approach ◽  
Average Loss ◽  
Actual Decision ◽  
Probabilistic Diagnosis

It is argued that it is preferable to evaluate probabilistic diagnosis systems in terms of utility (patient benefit) or loss (negative benefit). We have adopted the provisional strategy of scoring performance as if the system were the actual decision-maker (not just an aid to him) and argue that a rational figure of merit is given by the average loss which patients would incur by having the system decide on treatment, the treatment being selected according to the minimum expected loss principle of decision theory.A similar approach is taken to the problem of evaluating probabilistic prognoses, but the fundamental differences between treatment selection skill and prognostic skill and their implications for the assessment of such skills are stressed. The necessary elements of decision theory are explained by means of simple examples mainly taken from the acute abdomen, and the proposed evaluation tools are applied to Acute Abdominal Pain data analysed in our previous papers by other (not decision-theoretic) means. The main difficulty of the decision theory approach, viz. that of obtaining good medical utility values upon which the analysis can be based, receives due attention, and the evaluation approach is extended to cover more realistic situations in which utility or loss values vary from patient to patient.

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