| 1. |
- Nagaraja, Ch., et al.
(författare)
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Opening remarks
- 2016
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Konferensbidrag (refereegranskat)
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| 2. |
- Manova, S., et al.
(författare)
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Experimental investigation of heat transfer characteristics in a miniature flat heat pipe with multi-channels
- 2024
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Ingår i: International Journal of Heat and Mass Transfer. - : Elsevier Ltd. - 0017-9310 .- 1879-2189. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- The heat transfer characteristics of a miniatured flat heat pipe (MFHP) with multi-channels, featuring a port diameter of 1.18 mm, is investigated experimentally. Various operating parameters are considered, including the working fluid volume (Vf = 1.5, 2.5, and 3.5 ml), length of the liquid reservoir (Lres = No reservoir, 5, and 10 mm), orientation such as axial face (αa) or lateral side (αl), inclination angles (α = −15 to 90o), and cooling water flow rates (ṁi = 10, 15, and 20 LPH). Based on the experiments, the optimal values for the working fluid volume, reservoir length, and flow rate are determined as Vf = 2.5 ml, Lres = 5 mm, and ṁi = 20 LPH, respectively. Further analysis reveals that, the heat dissipation rate for the axial face is significantly higher than that of the lateral side, with an average percentage increase of 35.4 %. However, the lateral side outperforms the axial face in terms of stabilizing the evaporator wall temperature, reducing fluctuations by an average of 24.5 %. Moreover, the presence of multi-channels allows the MFHP in axial face orientation to dissipate a maximum heat load of 15 W against gravity at an inclination angle of αa = −15o. Finally, the variations in MFHP operation based on the orientation and its underlying physical mechanisms that contribute to enhancing heat transfer are discussed.
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| 3. |
- Mathews, T.S, et al.
(författare)
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Integration of functional reliability analysis with hardware reliability : An application to safety grade decay heat removal system of Indian 500 MWe PFBR
- 2009
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 36:4, s. 481-492
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Tidskriftsartikel (refereegranskat)abstract
- A passive system can fail either due to classical mechanical failure of components, referred to as hardware failure, or due to the failure of physical phenomena to fulfill the intended function, referred to as functional failure. In this paper a methodology is discussed for the integration of these two kinds of unreliability and applied to evaluate the integrated failure probability of the passive decay heat removal system of Indian 500 MWe prototype fast breeder reactor (PFBR). The probability of occurrence of various system hardware configurations is evaluated using the fault tree method and functional failure probabilities on the corresponding configurations are determined based on the overall approach reported in the reliability methods for passive system (RMPS) project. The variation of functional reliability with time, which is coupled to the probability of occurrence of various hardware system configurations is studied and incorporated in the integrated reliability analysis. It is observed that this consideration of the dependence of functional reliability on time will give significant advantages on system reliability. The integrated reliability analysis is also explained using an event tree. The impact of the provision for forced circulation in the primary circuit on functional reliability is also studied with this procedure and it is found that the forced circulation capability helps to bring down the total decay heat removal failure probability by lowering the peak temperatures after the reactor shut down.
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| 4. |
- Arul, A.J, et al.
(författare)
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Reliability analysis of safety grade decay heat removal system of Indian prototype fast breeder reactor
- 2006
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549. ; 33:2, s. 180-188
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Tidskriftsartikel (refereegranskat)abstract
- The 500MW Indian pool type Prototype Fast Breeder Reactor (PFBR), is provided with two independent and diverse Decay Heat Removal (DHR) systems viz., Operating Grade Decay Heat Removal System (OGDHRS) and Safety Grade Decay Heat Removal System (SGDHRS). OGDHRS utilizes the secondary sodium loops and Steam–Water System with special decay heat removal condensers for DHR function. The unreliability of this system is of the order of 0.1–0.01. The safety requirements of the present generation of fast reactors are very high, and specifically for DHR function the failure frequency should be less than 1E-7/ry. Therefore, a passive SGDHR system using four completely independent thermo-siphon loops in natural convection mode is provided to ensure adequate core cooling for all Design Basis Events. The very high reliability requirement for DHR function is achieved mainly with the help of SGDHRS. This paper presents the reliability analysis of SGDHR system. Analysis is performed by Fault Tree method using "CRAFT" software developed at Indira Gandhi Centre for Atomic Research. This software has special features for compact representation and CCF analysis of high redundancy safety systems encountered in nuclear reactors. Common Cause Failures (CCF) are evaluated by beta-factor method. The reliability target for SGDHRS arrived from DHR reliability requirement and the ultimate number of demands per year (7/y) on SGDHRS is that the failure frequency should be <=1.4E-8/de. Since it is found from the analysis that the unreliability of SGDHRS with identical loops is 5.2E-6/de and dominated by leak rates of components like AHX, DHX and sodium dump and isolation valves, options with diversity measures in important components were studied. The failure probability of SGDHRS for a design consisting of 2 types of diverse loops (Diverse AHX, DHX and sodium dump and isolation valves) is 2.1E-8/de, which practically meets the reliability requirement.
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| 5. |
- Arul, A.J., et al.
(författare)
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The power law character of off-site power failures
- 2003
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Ingår i: Annals of Nuclear Energy. - 0306-4549. ; 30:14, s. 1401-1408
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Tidskriftsartikel (refereegranskat)abstract
- A study on the behavior of off-site AC power failure recovery times at three nuclear plant sites is presented. It is shown, that power law is appropriate for the representation of failure frequency–duration correlation function of off-site power failure events, based on simple assumptions about component failure and repair rates. It is also found that the annual maxima of power failure duration follow Frechet distribution, which is a type II asymptotic distribution, strengthening our assumption of power law for the parent distribution. The extreme value distributions obtained are used for extrapolation beyond the region of observation.
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| 6. |
- Khan, B., et al.
(författare)
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Drawbacks of Artificial Intelligence and Their Potential Solutions in the Healthcare Sector
- 2023
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Ingår i: Biomedical Materials and Devices. - : Springer Nature. - 2731-4812 .- 2731-4820. ; 1:2, s. 731-738
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Tidskriftsartikel (refereegranskat)abstract
- Artificial intelligence (AI) has the potential to make substantial progress toward the goal of making healthcare more personalized, predictive, preventative, and interactive. We believe AI will continue its present path and ultimately become a mature and effective tool for the healthcare sector. Besides this AI-based systems raise concerns regarding data security and privacy. Because health records are important and vulnerable, hackers often target them during data breaches. The absence of standard guidelines for the moral use of AI and ML in healthcare has only served to worsen the situation. There is debate about how far artificial intelligence (AI) may be utilized ethically in healthcare settings since there are no universal guidelines for its use. Therefore, maintaining the confidentiality of medical records is crucial. This study enlightens the possible drawbacks of AI in the implementation of healthcare sector and their solutions to overcome these situations.
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| 7. |
- Kiran, P., et al.
(författare)
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Machine learning based 64-QAM classification techniques for enhanced optical communication
- 2023
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Ingår i: Optical and quantum electronics. - : Springer. - 0306-8919 .- 1572-817X. ; 55:13
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Tidskriftsartikel (refereegranskat)abstract
- Due to their greatly increased spectrum efficiency, high-order quadrature amplitude modulation (QAM) formats are especially successful at increasing transmission capacity. QAM is extremely sensitive to nonlinear distortion because of its dense constellation and SNR-hungry configuration. Autonomous neural network (ANN) derived nonlinear decision boundaries that are adaptively created by machine learning techniques can be used to classify symbols. The proposed work focusing on the quadrature amplitude modulation (QAM) scheme, the approach is to formulate an autonomous neural network (ANN) that can predict the class of each symbol from a signal stream of symbols. Experimental accuracy for each ANN's of proposed work achieves 89% by analysing all tests. Comprehensive results are presented with comparisons, demonstrating notable nonlinear mitigation with BER reductions. Additionally, it offers a glimpse into potential future research plans intended to raise the likelihood that predictions would come true and their accuracy.
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| 8. |
- Mathews, T.S, et al.
(författare)
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Functional reliability analysis of Safety Grade Decay Heat Removal System of Indian 500 MWe PFBR
- 2008
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 238:9, s. 2369-2376
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Tidskriftsartikel (refereegranskat)abstract
- Passive systems are increasingly deployed in nuclear industry with an objective of increasing reliability and safety of operations with reduced cost. Methods for assessing the reliability of thermal-hydraulic passive systems, that is systems with moving working fluid, address the issues in natural buoyancy-driven flow that could result in a failure to meet the design safety limits under accident scenarios. This is referred as design functional reliability. This paper presents the results of functional reliability analysis carried out for the passive Safety Grade Decay Heat Removal System (SGDHRS) of IndianPrototype Fast Breeder Reactor (PFBR). The analysis is carried out based on the overall approach reported in the Reliability Methods for Passive System (RMPS, European Commission) project. Functionalfailure probability is calculated using Monte-Carlo method and also with method of moments.
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| 9. |
- Ramakrishnan, M., et al.
(författare)
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Estimation of station blackout frequency for Indian fast breeder test reactor
- 2008
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549. ; 35:12, s. 2332-2337
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the comparison of station blackout (SBO) frequency computed with approximate time averaged expressions for diesel generator unavailability and time dependent cutset evaluation method. It is found that the frequency of SBO is under predicted by a factor of 2 by approximate time averaged expressions for SBO durations of 8 h and 16 h. The time dependent cutset evaluation method is applied for offsite power feeder outage management by treating the change in SBO frequency when one of the feeders is taken out for maintenance for ‘n’ days, as the risk measure.
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| 10. |
- Yadav, J. S., et al.
(författare)
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Stabilized old landfill leachate treatment using electrocoagulation
- 2017
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Ingår i: EnvironmentAsia. - 1906-1714. ; 10:1, s. 25-33
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Tidskriftsartikel (refereegranskat)abstract
- Electrocoagulation of leachate samples was performed by using aluminium and iron electrodes. The objective of study was to optimize the parameters such as current density, electrolysis time and pH for maximum removal of chemical oxygen demand by electrocoagulation process from landfill leachate collected from Deonar landfill in Mumbai, India. Landfill leachate was found to have Turbidity (177 NTU), Chemical oxygen demand (2300 mg/l), low BOD/COD ratio (0.10) and Total solids (10910) mg/l respectively. The Chemical Oxygen Demand (COD) of leachate sample was found to be 2300 mg/l and Biochemical Oxygen Demand (BOD) confirming that it was old or stabilized leachate. 47% COD was removed at current density of 466A/m2 with optimum electrolysis time of 60 mins and pH 8 with aluminium electrode while for iron electrodes, the COD removal efficiency came out to be 56% at current density of 466A/m2, optimum electrolysis time 90 mins and pH 6.
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