Impedance and modulus analysis of barium calcium titanate ferroelectric ceramics

Patel Satyanarayan,Kodumudi Venkataraman Lalitha,Yadav Harekrishna 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.3

BaTiO 3 -based derivatives have been explored in recent times for potential applications in energy harvesting and ultrasonics. To this end, energy harvesting and conversion applications require an understanding of the conduction and loss mechanisms. The conduction mechanism in Ba 0.9 Ca 0.1 TiO 3 (BCT) ceramics is studied using impedance spectroscopy at different temperatures. Impedance analysis suggests the presence of two types of relaxation processes corresponding to grain and grain boundary contributions. The relaxation mechanism follows non-Debye-type behavior. The high resistance of the grain (bulk) in the ferroelectric region does not contribute to the high losses; the losses probably result from the phase transition. In addition, BCT ceramics exhibit a negative temperature coefficient of resistance (NTCR). The open-circuit pyroelectric voltage shows a twofold increase compared to (Ca, Zr) modification in BaTiO3.

Effect of uniaxial stress on energy harvesting, storage and electrocaloric performance of BZT ceramics

Patel Satyanarayan,Yadav Harekrishna,Kumar Manish 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.4

In this work, a systematic approach of waste (thermal/mechanical) energy harvesting and storage potential is studied in Ba 0.85 Zr 0.15 TiO 3 (BZT) ceramics. The eff ect of stress on energy storage density (harvesting/storage) and electrocaloric per- formance is also studied. For this purpose, polarization–electric fi eld hysteresis loops were recorded at various temperatures and uniaxial compressive stress. The Olsen cycle and electro-mechanical cycle are used for direct waste heat or mechanical energy to electrical energy conversion. A thermal energy-harvesting density of 42 kJ/m 3 per cycle was obtained when the Olsen cycle was operated between 296–343 K and 0.25–1.5 MV/m. The electro-mechanical cycle-based energy harvesting is estimated as 78 kJ/m 3 under the applied stress of 5–160 MPa and the electric fi eld of 0.25–1.5 MV/m. The energy storage density is found as 39 kJ/m 3 at zero stress fi eld and 343 K, which increases to 53 kJ/m 3 under the biased stress of 80 MPa in a wide operating temperature range of 296–328 K. It is observed that the high energy storage is a result of the reduction of the hysteresis loss. The electrocaloric temperature is found as 0.16 K and 0.18 K under the 0 and 80 MPa stress fi elds, respectively. Overall, the reported fi ndings will enrich our understanding of the stress eff ect on BZT materials, which off ers high performance for energy harvesting and storage-based applications. Moreover, this work can be also helpful in improv- ing the energy storage density and electrocaloric eff ect via stress confi nement.

Quick Sequential (Sepsis Related) Organ Failure Assessment: A high performance rapid prognostication tool in patients having acute pyelonephritis with upper urinary tract calculi

Siddharth Pandey,Satyanarayan Sankhwar,Apul Goel,Manoj Kumar,Ajay Aggarwal,Deepanshu Sharma,Samarth Agarwal,Tushar Pandey 대한비뇨의학회 2019 Investigative and Clinical Urology Vol.60 No.2

Purpose: To analyze the utility of quick Sequential Organ Failure Assessment (qSOFA) in patients with uro-sepsis due to acute pyelonephritis (APN) with upper urinary tract calculi, we conducted this study. The role of qSOFA as a tool for rapid prognostication in patients with sepsis is emerging. But there has been a great debate on its utility. Literature regarding utility of qSOFA in uro-sepsis is scarce. Materials and Methods: Ours was a retrospective study including 162 consecutive patients who were admitted for APN with upper urinary tract calculi over a 3 and half years (total 42 months) period. We evaluated the accuracy of qSOFA in predicting inhospital mortality and intensive care unit (ICU) admissions and compared this with the predictive accuracy of systemic inflammatory response syndrome (SIRS). We used the Area Under Curve (AUC) of the Receiver Operator Characteristic curve to calculate it and also calculated the optimum cut off for qSOFA score. Results: The overall mortality and ICU admission rates were 7.4% and 12.9%, respectively. qSOFA had a higher predictive accuracy for in-hospital mortality (AUC, 0.981; 95% confidence interval [CI], 0.962–1.000) and ICU admissions (AUC, 0.977; 95% CI, 0.955–0.999) than SIRS. A qSOFA score of ≥2 was an optimum cut off for predicting prognosis. In a multivariate model qSOFA ≥2 was a highly significant predictor of in-hospital mortality and ICU admissions (p<0.001). Conclusions: qSOFA is a reliable and rapid bedside tool in patients with sepsis with accuracy more than SIRS in predicting inhospital mortality and ICU admissions.

GT-PSO- An Approach For Energy Efficient Routing in WSN

Priyanka, R,Reddy, K. Satyanarayan International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.4

Sensor Nodes play a major role to monitor and sense the variations in physical space in various real-time application scenarios. These nodes are powered by limited battery resources and replacing those resource is highly tedious task along with this it increases implementation cost. Thus, maintaining a good network lifespan is amongst the utmost important challenge in this field of WSN. Currently, energy efficient routing techniques are considered as promising solution to prolong the network lifespan where multi-hop communications are performed by identifying the most energy efficient path. However, the existing scheme suffer from performance related issues. To solve the issues of existing techniques, a novel hybrid technique by merging particle swarm optimization and game theory model is presented. The PSO helps to obtain the efficient number of cluster and Cluster Head selection whereas game theory aids in finding the best optimized path from source to destination by utilizing a path selection probability approach. This probability is obtained by using conditional probability to compute payoff for agents. When compared to current strategies, the experimental study demonstrates that the proposed GTPSO strategy outperforms them.

A prospective study evaluating impact on renal function following percutaneous nephrolithotomy using Tc99m ethylenedicysteine renal scan: Does multiplicity of access tracts play a role?

Ram Yadav,Samarth Agarwal,Satyanarayan Sankhwar,Apul Goel,Manoj Kumar,Manmeet Singh,Ruchir Aeron,Vikas Kumar 대한비뇨의학회 2019 Investigative and Clinical Urology Vol.60 No.1

Purpose: A prospective study evaluating impact of percutaneous nephrolithotomy (PCNL) on renal function following PCNL using ethylenedicysteine (EC) renal scan. Does multiplicity of access tracts play a role?Materials and Methods: A prospective observational study was done and patients undergoing PCNL for renal calculi at our urology department were selected. Renal Tc99m EC scan was done pre-surgery and at 3 months follow-up. An assessment was done on decline in glomerular filtration rate (GFR) in postoperative period based on number of access tracts required. Results: A total of 110 patients were enrolled in the study. The total number of punctures was 170 with 141 being supra-costal puncture and 29 infra-costal. The total number of single punctures were 60 and classified as Group I whereas patients with double puncture and triple puncture (40 and 10 patients, respectively) were classified as Group II. Mean postoperative split renal function (in Tc99m EC scans) of patients of Group I (40.93±19.62%) was found to be higher than that of Group II (32.82±16.98%). Mean change (decline) in GFR for single, double and triple tracts were 2.68 mL/min, 3.80 mL/min, and 4.2 mL/min, respectively. Conclusions: PCNL used for stone removal can improve renal function by eradicating obstruction; however, this procedure may itself negatively impact the functions of the targeted kidney. Our study showed post PCNL decrease in GFR which worsens with an increasing number of accesses.

Temperature and frequency depended structural, morphological, and electrical topographies of Bi2MnFeO6 double perovskite

Tripathy A.,Bhuyan Satyanarayan,Das S. N.,Choudhary R. N. P. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2

A double perovskite ceramic electronic sample of Bi2MnFeO6 has been formulated and synthesized using an ordinary solid-state sintering route from the metal oxides of bismuth, manganese, and iron. The crystallographic structure, morphological, dielectric, electrical, and current–voltage parameters have been analyzed for the fabricated sample. Room temperature XRD (X-ray diffraction) investigation confirms the monoclinic phase. The microstructure obtained from scanning electron microscope reveals compact grain structures with little or no voids. The impedance as well as its electrical properties have been appraised through the impedance analyzer (LCR meter) for a wide range of temperatures and frequencies (30–230 °C and 1 kHz–1 MHz). The negative temperature coefficient of the material is derived from the impedance analysis. The non-ohmic behavior of the sample was confirmed by the current versus voltage (V–I) characteristic of the sample. Most of the significant physical and chemical properties linked with this compound may be critical in the development of future peer group electrical and electronic devices.

Are there any predictive risk factors for failure of ureteric stent in patients with obstructive urolithiasis with sepsis?

Siddharth Pandey,Deepanshu Sharma,Satyanarayan Sankhwar,Manmeet Singh,Gaurav Garg,Ajay Aggarwal,Ashish Sharma,Samarth Agarwal 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.6

Purpose: To compare patients with sepsis due to obstructive urolithiasis (Sep-OU) and underwent drainage by percutaneous nephrostomy (PCN) or a double-J (DJ)-ureteral stent and to identify predictive risk factors of DJ stent failure in these patients. Materials and Methods: We reviewed our records from January 2013 to July 2018 and identified 286 adult patients with Sep-OU out of which 36 had bilateral involvement, thus total 322 renal units were studied. Urologic residents in training carried out both ureteral stenting and PCN tube placement. Demographic data and stone characteristics were recorded along with Charlson comorbidity index. For predicting risk factors of DJ stent failure, those variables that had a p-value <0.1 in univariate analysis were combined in a multinomial regression analysis model. Results: The patients with PCN placement were significantly older than those with DJ stent placement (p=0.001) and also had significant number of units with multiple calculi (p=0.018). PCN was also placed more frequently in those patients with a upper ureteric calculi (p<0.05). On multinomial regression analysis multiple calculi (p=0.014; odds ratio [OR], 4.878; 95% confidence interval [CI], 1.377–17.276) and larger calculi size (p=0.040; OR, 0.974; 95% CI, 0.950–0.999) were the significant predictors of DJ stent failure. Conclusions: In patients with sepsis from obstructive urolithiasis due to larger and multiple calculi a PCN placement might be better suited although this data requires further prospective randomized studies to be extrapolated.

분극반전된 LiTaO3 광도파로에서의 주파수 증배에 의한 고출력 청색광 발생 ( High Power Blue Light Generation in a Domain-Inverted LiTaO3 Waveguide by Frequency Doubling )

진용성,손영성,유태경,M. N. Satyanarayan 한국통신학회 1997 광전자공학회 학술회의 Vol.4 No.1

Secure Device to Device Communications using Lightweight Cryptographic Protocol

Ajith Kumar, V,Reddy, K Satyanarayan International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.11

The device to device (D2D) communication is an important and emerging area for future cellular networks. It is concerned about all aspect of secure data transmission between end devices along with originality of the data. In this paradigm, the major concerns are about how keys are delivered between the devices when the devices require the cryptographic keys. Another major concern is how effectively the receiver device verifies the data sent by the sender device which means that the receiver checks the originality of the data. In order to fulfill these requirements, the proposed system able to derive a cryptographic key using a single secret key and these derived keys are securely transmitted to the intended receiver with procedure called mutual authentication. Initially, derived keys are computed by applying robust procedure so that any adversary feel difficulties for cracking the keys. The experimental results shows that both sender and receiver can identify themselves and receiver device will decrypt the data only after verifying the originality of the data. Only the devices which are mutually authenticated each other can interchange the data so that entry of the intruder node at any stage is not possible.

Contactless Stimulation of Multiple Piezoelectric Devices Using Electric Field

Tanaya Nayak,Biswaranjan Swain,Praveen P. Nayak,Satyanarayan Bhuyan 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.3

The contactless energy transmission scheme using parallel-plate capacitor like structure has been explored which provides a platform for energization of multiple piezoelectric (piezo) components. In the proposed method, ac electric fi eld lines produced by copper electrodes penetrate to the piezo components that are coaxially aligned and positioned in-between at certain distance away from each electrode. Consequently, the components are strongly excited at a point where the functioning electric field source frequency alike with the mechanical resonant frequency of the piezo components. The maximum output power corresponding to optimum load and resonant frequency acquired from the contactless energized multi piezo devices is better than that of power obtained from contactless energized single piezo component by this parallel-plate capacitor electric field generator. The testing results reveal the practicability of non contact stimulation/excitation of multi piezo components simultaneously through electric fi eld.