| 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. |
- 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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| 4. |
- 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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| 5. |
- Dimov, Aleksandar, et al.
(författare)
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Mutation testing framework for software reliability model analysis and reliability estimation
- 2010
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Ingår i: Central and Eastern European Software Engineering Conference (CEE-SECR). - 9781457706066 ; , s. 163-169
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Konferensbidrag (refereegranskat)abstract
- After several years of research, even today estimation of software reliability is extremely challenging. The undeterministic nature of the factors that contribute to the reliability estimation has led to the development of numerous statistical models for this purpose. One of the important factors that contribute to software reliability is testing. The aim of this paper is to use mutation testing for estimating the „true” reliability of a system and provide a framework for estimation of uncertainty bounds associated with testing and a measure for factors such as test coverage, time between failures and code coverage that contribute to the estimation of reliability and use mutation testing as a tool to create a software failure dataset. The approach is experimented with an open source search tool.
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| 6. |
- Khan, Bangul, et al.
(författare)
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Recent progress in thermosensitive hydrogels and their applications in drug delivery area
- 2023
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Ingår i: MedComm – Biomaterials and Applications. - 2769-643X .- 2769-643X. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- The scientific community has widely recognized thermosensitive hydrogelsas highly biocompatible material withimmense potential in drug deliverysystems. When the temperature of these hydrogels approaches that ofhuman body, a phase change occurs, enhancing their usefulness in a rangeof medical scenarios. This review article highlighted the background ofthermosensitive hydrogels, their properties, and their applications intransdermal, oral, ophthalmic, intravaginal, nasal, rectal, cancer therapy,and cell‐loaded drug delivery systems. The literature suggests numerousadvantages of these hydrogels over conventional drug delivery systems andfind applications in various fields, such as therapeutic systems, fillingprocesses, and sustained drug delivery systems. One of their key benefits isthe ability to eliminate invasive procedures like surgery, providing anoninvasive alternative for drug administration. Moreover,theystreamlinethe formulation process for both hydrophilic and hydrophobic drugdelivery systems, simplifying the development of effective treatments.The thermosensitive hydrogels have been found to be green materials withnegligible side effects and desirable drug delivery properties. Thethermosensitive hydrogel's sustained‐release characteristics, immunogenic-ity, and biodegradability have also gained increased interest. Some of thedisadvantages of thermosensitive hydrogels include delayed temperatureresponse, weak mechanical characteristics, and poor biocompatibility,which limits their potential use in drug delivery applications.
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| 7. |
- Maji, K. J., et al.
(författare)
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Assessment of city level human health impact and corresponding monetary cost burden due to air pollution in India taking Agra as a model city
- 2017
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 17:3, s. 831-842
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Tidskriftsartikel (refereegranskat)abstract
- Objectives of the present study are to provide quantitative estimations of air pollution health impacts and monetary burden on people living in Agra city, the fourth most populated city in Uttar Pradesh, India. To estimate the direct health impacts of air pollution in Agra city during year 2002 to 2014, ‘Risk of Mortality/Morbidity due to Air Pollution’ model was used which is adopted from air quality health impact assessment software, developed by world health organization (WHO). Concentrations of NO2, SO2 and PM10 have been used to assess human health impacts in terms of attributable proportion of the health outcome as- annual number of excess cases of total mortality, cardiovascular mortality, respiratory mortality, hospital admission chronic obstructive pulmonary disease (COPD), hospital admission respiratory disease and hospital admission cardiovascular disease and it was observed that attributable number of cases were 1325, 908, 155, 138, 1230 and 348 respectively in year 2002. However, after thirteen years these figures increased to 1607, 1095, 189, 167, 1568 and 394 respectively. From these results, it was observed that from 2002 to 2014, the attributable number of cases increased almost by 13.43 to 27.52%. As a result, the monetary cost burden due to air pollution related health effects also increased very highly; it was 67.99 million US$ in 2002, which transformed into 254.52 million US$ in 2014. In future, if air quality continues to follow current pollutant concentration trend, the monetary cost burden will reach a level of US$ 570.12 million in year 2020, which is not only a thoughtful matter but also a threatful matter and it signifies the importance of rectification measures for air quality in Agra city.
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| 8. |
- Maji, K. J., et al.
(författare)
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Classification of air quality monitoring stations using fuzzy similarity measures : A case study
- 2016
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Ingår i: Studies in Fuzziness and Soft Computing. - Cham : Springer International Publishing. - 1434-9922 .- 1860-0808. ; 342, s. 489-501
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Tidskriftsartikel (refereegranskat)abstract
- The objective of designing and installation air quality monitoring network (AQMN) is to reduce network density with a view to acquire maximum information on air quality with minimum expenses. In spite of the best research efforts, there has been no general acceptance of any method for deciding the number of stations. Majority of the cities have, therefore, installed monitoring stations with their own guidelines. The present paper presents a useful formulation for classification of the existing air quality monitoring stations (AQMS) using fuzzy similarity measures. The case study has been demonstrated by applying the methodology to the already-installed AQMS in Delhi, India.
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| 9. |
- 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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| 10. |
- 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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