Actual Lifetime Research Articles

Fatigue life estimation of nickel-based single crystal superalloy with different inclined film cooling holes: Initial damage quantification and coupling of damage-fracture mechanics models

Quantitative assessment of the initial damage state of a structure and fatigue life prediction on this basis, especially when it is sensitive to manufacturing quality, is crucial for both engineering application and material science. Traditional solutions based on fracture or damage mechanics either require precise constitutive relationships and cumbersome physical mechanism models or simply ignore the initial damage state. This study developed a novel equivalent initial flaw size (EIFS) quantitative evaluation method for film cooling holes in Nickel-based single crystal superalloy turbine blades to address the strong correlation between the initial damage in and fatigue life of the material. The temperature and stress field differences at the edges of holes with different inclination angles were simulated using a solid-liquid-gas three-phase level-set model and considered to represent the same initial damage. Next, the coupled damage–fracture mechanics model was used to achieve equivalent crack insertion, crack propagation, and fatigue life prediction based on the EIFS. The results indicate that this method can provide a highly robust EIFS distribution interval and that the crack geometry correction factor and EIFS distribution range are weakly correlated with the loading conditions (with an error within 2 %). The EIFS-based fatigue life predictions demonstrated a notable degree of accuracy, with the majority of the predicted and experimental fatigue lives falling within a three-fold dispersion band and all predictions remaining confined within a five-fold dispersion band of the actual lifetime. These results represent a substantial advancement in accuracy compared to traditional damage mechanics predictions. Therefore, this study provides a powerful approach for evaluating the fatigue life of turbine blades considering the initial damage state and can be widely applied to guide drilling process optimization and blade fatigue analysis.

Abstract 3465: Association with total reproductive year and the risk of biliary tract cancer in women

Abstract Background: Many studies have reported that female reproductive factors, such as parity, age at menarche or menopause, breastfeeding, or age at first birth, were associated with or not associated with the development of biliary tract cancer (BTC). Our study was planned to determine whether a long-term rather than transient exposure was associated with the risk of BTC, including total reproductive year, which was defined as the time from menarche to menopause throughout the life cycle. Methods: This nationwide cohort study included 1,059,533 women with natural menopausal women aged 40-69 years who underwent the periodic health check-up provided by the Korean National Health Insurance System in 2009. The median follow-up period was 9.3 years. Cox proportional hazard regression analysis was performed to estimate the risk of BTC based on the female reproductive factors. Results: During the 9,867,152 person-years of follow-up, 4,198 patients (0.4%) were newly diagnosed with BTC. The incidence of BTC was significantly increased in subjects younger than 40 years at menopause compared with those aged 40 years or older (HR 1.341, 95% CI, 1.095-1.642). This trend was consistent even when menopause age was subdivided into 5-year intervals (<40 vs. 40−44, 45−49, 50-54, and ≥ 55 years) for those aged 40 years or older. When compared by categorization into four quartiles, the incidence of BTC tended to be numerically lower than that of the bottom 25% with the lowest age of menopause (designated as Q1 reference group). Compared to those with total reproductive year of 30 years or more, the incidence of BTC increased significantly in the group with less than 30 years of total reproductive year (HR 1.106, 95% CI, 1.014-1.206). This tendency was significantly reproduced in comparison by categorizing the entire group into quartiles. Compared to the lower 25% group (designated as Q1 reference group), the risk of BTC showed a significant linear inverse correlation with the longer total reproductive year. Q1 group has significantly higher incidence of BTC compared to the other groups (p < 0.001). This trend was repeated in various subgroup analysis. Conclusions: In conclusion, this study demonstrated that women under the age of 40 at menopause had an increased risk of BTC compared to those over 40 years of age. Similarly, a longer period of total reproductive year was associated with a lower risk of BTC, suggesting a protective female hormonal effect on BTC. Total reproductive year may be more reliable indicator in that it reflects the actual lifetime exposure to female hormones. Citation Format: Chi Hoon Maeng, Kyungdo Han, Joo-Hyun Park, Jung Yong Hong. Association with total reproductive year and the risk of biliary tract cancer in women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3465.

Assessing the overflowing pile-up effect on the photoluminescence lifetime of nanomaterials.

The tunable complex emissive states with nanosecond to microsecond lifetimes in nanomaterials, arise due to their structural heterogeneity, enabling them with a wide range of advanced optoelectronic applications. However, understanding the complex photoluminescence lifetime in these nanomaterials is critically challenged by the overflowing pile-up effect, which occurs due to the high repetition rate of the light source in the time-correlated single photon counting (TCSPC) technique. Here, we provide a quantitative lifetime analysis, especially in metal nanoclusters, metal complexes, and semiconductor quantum dots, which suggests that the same experimental parameters can mislead the lifetime data interpretation for long-ranged luminescent nanomaterials. We demonstrate that the overflowing pile-up effect could be fatal while analyzing the excited state lifetime. Furthermore, we provide the optimized parameters that could be used to get the actual lifetime data of samples. We hope that our findings will be crucial in obtaining the error-free and accurate excited state dynamics of these long-range lifetime nanomaterials.

ДОСЛІДЖЕННЯ ТЕХНІЧНОГО СТАНУ НЕСУЧИХ МЕТАЛОКОНСТРУКЦІЙ ВАГОНІВ ТЯГОВОГО ЕЛЕКТРОРУХОМОГО СКЛАДУ ЗАЛІЗНИЦІ ГРУЗІЇ

The article analyzes the operational fleet of electric traction rolling stock of the Georgian railway. It has been established that the majority of the operating vehicles used in suburban traffic consists of electric trains of the Riga Wagon-Building Plant that have served their specified service lifetime. The need to extend the service lifetime of existing electric railway vehicles as an alternative to purchasing new ones is substantiated. Scientific and experimental studies of the technical condition of traction electric rolling stock wagons and their supporting metal structures were carried out in order to determine the actual remaining service lifetime and make a reasoned decision about the feasibility of renovation and extending the service life of the examined wagons. An examination of the technical condition of all provided wagons was carried out, and the actual residual lifetime of each of them was determined based on the results of the study. It has been established that there are practically no mechanical damages to the elements of the metal structures of the car bodies. Significant local corrosion damage of the elements on the body bolster in the area where the toilets are located was revealed. At the same time, the general technical condition of the body bolster is completely satisfactory. Detected corrosion damage of the main bearing elements of metal structures is local in nature and does not exceed permissible values. The examined metal structures of the bodies of ЕР2 type electric trains have minor mechanical and corrosion damage. The possibility of modernizing electric train cars of the ЕР2 type with an extension of the service life for 5 years based on the results of determining their actual residual lifetime is substantiated.

Passive Photovoltaic Cooling: Advances Toward Low‐Temperature Operation

AbstractWith the great increase in installation, photovoltaics will develop as the main power supply source for the world shortly. However, the actual power generation and lifetime of photovoltaics are greatly compromised by the high working temperature under outdoor operation. In this review, the recent advances of four promising passive photovoltaic cooling methods are summarized with the aim to uncover their working principles, cooling performance, and application potential in photovoltaic devices. For radiative cooling, light management strategies with ultraviolet‐photon downshift and sub‐bandgap reflection are discussed in detail to reveal their great potential in reducing photovoltaic working temperature and enhancing power generation. Subsequently, the great cooling benefits of passive evaporative cooling are underlined in terms of its superior cooling power and temperature drop of photovoltaic devices. Moreover, the promising integrated cooling strategy is further highlighted due to its great potential in enhancing electricity production and fresh water supply. Most crucially, the remaining challenges and the authors'r insights are presented to advance the commercial applications of passive cooling methods in photovoltaics.

Uncovering the role of substance use in suicide attempts using a mixed-methods approach.

Substance use is an established risk factor for suicide attempt. Clarifying the role of substance use in suicide attempts may identify modifiable treatment targets. This study used mixed methods to associate substance use with suicide attempt history and identify pathways through which substance use contributes to attempts. Study 1 included 213 adult inpatients (n = 127 with substance use disorder [SUD]), who completed assessments of suicide attempt history as well as demographic and clinical suicide risk factors. Study 2 was a narrative analysis of suicide attempt stories described by 20 inpatients diagnosed with SUD. In Study 1, patients with co-occurring alcohol and drug use disorders reported more actual lifetime suicide attempts than did those without SUD. In addition, alcohol and drug use disorders were independently associated with lifetime suicide attempts after controlling for demographic and clinical confounders. In Study 2, substance use played a role in all suicide attempts through at least one pathway before, during, or after a triggering stressor, or as suicide attempt method. Substances play a role in suicide attempt baseline risk, acute risk and as means. It is important to target chronic and acute substance use in suicide prevention treatment plans.

Deep Bayesian survival analysis of rail useful lifetime

Reliable estimation of rail useful lifetime can provide valuable information for predictive maintenance in railway systems. However, in most cases, lifetime data is incomplete because not all pieces of rail experience failure by the end of the study horizon, a problem known as censoring. Ignoring or otherwise mistreating the censored cases might lead to false conclusions. Survival approach is particularly designed to handle censored data for analysing the expected duration of time until one event occurs, which is rail failure in this paper. This paper proposes a deep Bayesian survival approach named BNN-Surv to properly handle censored data for rail useful lifetime modelling. The proposed BNN-Surv model applies the deep neural network in the survival approach to capture the non-linear relationship between covariates and rail useful lifetime. To consider and quantify uncertainty in the model, Monte Carlo dropout, regarded as the approximate Bayesian inference, is incorporated into the deep neural network to provide the confidence interval of the estimated lifetime. The proposed approach is implemented on a four-year dataset including track geometry monitoring data, track characteristics data, various types of defect data, and maintenance and replacement (M&R) data collected from a section of railway tracks in Australia. Through extensive evaluation, including Concordance index (C-index) and root mean square error (RMSE) for evaluating model performance, as well as a proposed CW-index for evaluating uncertainty estimations, the effectiveness of the proposed approach is confirmed. The results show that, compared with other commonly used models, the proposed approach can achieve the best concordance index (C-index) of 0.80, and the estimated rail useful lifetimes are closer to real lifetimes. In addition, the proposed approach can provide the confidence interval of the estimated lifetime, with a correct coverage of 81% of the actual lifetime when the confidence interval is 1.38, which is more useful than point estimates in decision-making and maintenance planning of railroad systems.

Survey of open science practices and attitudes in the social sciences

Open science practices such as posting data or code and pre-registering analyses are increasingly prescribed and debated in the applied sciences, but the actual popularity and lifetime usage of these practices remain unknown. This study provides an assessment of attitudes toward, use of, and perceived norms regarding open science practices from a sample of authors published in top-10 (most-cited) journals and PhD students in top-20 ranked North American departments from four major social science disciplines: economics, political science, psychology, and sociology. We observe largely favorable private attitudes toward widespread lifetime usage (meaning that a researcher has used a particular practice at least once) of open science practices. As of 2020, nearly 90% of scholars had ever used at least one such practice. Support for posting data or code online is higher (88% overall support and nearly at the ceiling in some fields) than support for pre-registration (58% overall). With respect to norms, there is evidence that the scholars in our sample appear to underestimate the use of open science practices in their field. We also document that the reported lifetime prevalence of open science practices increased from 49% in 2010 to 87% a decade later.

The Shakespeare Authorship Question: A Forensic Examination

Most authorship disputes are between rival authors, between two or more writers for whom there is conflicting evidence within the works themselves, or conflicting testimony from others about who exactly composed what. The Shakespeare Authorship Question, however, is quite different. It is based on assumptions about the supposed author’s life, on a stunning absence of testimony by people who actually knew him, as well as silence by the author himself. That is, the traditional attribution is based on a lack of direct knowledge. Despite centuries of intense research and investigation, no credible evidence from his actual lifetime has emerged linking Will Shakspere of Stratford to the illustrious dramatic canon of the author who wrote under the pseudonym William Shakespeare. One major aspect of this search has been attempts by scholars to find individuals among Shakspere’s family, friends, and co-workers who spoke of him as a writer. It turns out that no one who lived and worked during the Stratford man’s dates ever did. Nor did he or any member of his family or his descendants ever claim that he was a writer. There is simply no contemporary record of anyone mentioning him in connection with playwriting. Even among the few literary men who were personally acquainted with him – poet and playwright Michael Drayton and historian William Camden to name two -- neither ever mentioned him as a writer in their accounts of prominent men from the county of Warwickshire. Other residents of the Stratford area -- some of whom were quite familiar with the London theatrical scene -- never referred to him at all, much less as a dramatist. This included the theatergoer Edward Pudsey and the poet and playwright Fulke Greville, also Warwickshire residents. Dr. John Hall, who married Shakspere’s daughter Susanna in 1607, practiced medicine in Stratford for 30 years and wrote about his most interesting patients, never mentioned his father-in-law as a writer. This absence of direct knowledge and this absence of living testimony is unique in the history of authorship disputes. This article looks in detail at the silences of those around the Stratford man, people who should have mentioned his writing but didn’t, and ask what part such silence should play in knowledge formation.

A practical approach to LDAR effectiveness evaluation

As a growing number of oil and gas facilities worldwide implement leak detection and repair (LDAR) plans, the owners and the public are interested in better understanding their effectiveness, i.e. how total facility leak emission is decreased as a result of LDAR implementation. For this objective, it is critically important when calculating total mass leak emission to consider an estimated leak lifetime for the leakers found. Obviously, more frequent monitoring and shorter leak repair time should return lower leak lifetime and less emission. This simple yet important factor is mentioned but not detailed in existing guides. Some guides suggest formulae with the same equipment operating time both for leakers and non-leakers, which is not quite accurate since the actual leak lifetime could be significantly less than the total equipment operating time due to the proper LDAR implementation. In this article, we address this gap. The LDAR effectiveness evaluation approach utilizing leak lifetime is suggested and illustrated using examples.

Long-Term Orbital Lifetime Prediction of Highly Eccentric Orbits: A Statistical Approach

This paper concentrates on the long-term orbital lifetime prediction of highly eccentric orbits (HEOs) based on two-line element sets via a statistical approach. Due to the significantly different evolution characteristics of low- and high-inclination HEOs induced by different orbital resonances, two area-to-mass estimation methods are proposed, respectively. The resonance phenomena encountered in the HEO region strongly affect the orbital evolution and cause high sensitivity. Therefore, a statistical approach is adopted to handle these effects and correctly estimate low-inclination HEO lifetime. We use the Monte Carlo method and kernel-density estimation to calculate the probability distribution of the orbital lifetime. Finally, the performance of the method is assessed by the actual orbital lifetimes of space objects that reentered from HEOs in the past 50 years. The results indicate that our statistical approach can improve the orbital lifetime prediction accuracy to a large extent, especially for the low-inclination HEOs. If a relative error of 15% is adopted as the error tolerance, compared with the traditional method based on a single orbital propagation, our statistical method can increase the success rate from 40% to more than 70%. For the high-inclination HEOs, the objects with a relative error below 15% account for more than 90%.

Quantifying the Degree of Eddy Quasi‐Geostrophy by Generalizing Rossby Deformation

AbstractThe quasi‐geostrophy (QG) of oceanic eddies is scientifically challenging and observationally puzzling because of its marginally balanced yet resolvable nature. Here a quantitative analysis on the degree of eddy QG is carried out using altimetric sea surface height data from multiple missions. We propose a metric of Rossby period of deformation (Td) as an extension to the Rossby radius of deformation (Rd) and its related phase speed of the first baroclinic Rossby wave (Cd) which satisfies Td = Rd/Cd, implying that any robust eddy with a length scale of ∼Rd is supposed to survive for a period longer than the Rossby period ∼Td under an average propagation speed of ∼Cd if a quasi‐geostrophic balance can be maintained. In terms of a generalized Rossby deformation with regards to Rd, Td, and Cd, three indices are defined as baselines to characterize the spatial, temporal, and dynamic aspects of eddy QG according to their effective size, actual lifetime, and propagation speed, respectively.

Reduced real lifetime of PV panels – Economic consequences

The maintenance and analyzing failures of PV systems and plants are becoming more and more important issues. Our data from the long-term operation of 85 photovoltaic power plants in central Europe show that their actual lifetime is about half that of the originally planned lifetime. After about 10 years, serious failures of 1st tier (bankable) PV panels occur at an increasing rate. This article presents selected typical data and describes the most serious failures. Furthermore, economic calculations of returns on investment are carried out in relation to the price of electricity, which is currently changing at a rapid pace. It shows that the PV panel lifetime reduction from 20 to 30 years, declared at commercial leaflets, to real lifetime about 10–12 years can reduce PV power plant profit substantially, but the investment is still worth it. The reason is that after 10–12 years ser vice/maintenance expenses to replace damaged PV panels and inverters are growing very quickly. The new information could be helpful for owners of PV power plants to get a more realistic estimation of profits.

Until death do us part? In‐depth insights into Dutch consumers’ considerations about product lifetimes and lifetime extension

AbstractLong‐lasting electronic products contribute to a sustainable society; however, both expected and actual lifetimes are in decline. This research provides in‐depth insights into consumers’ considerations about product lifetimes, barriers to extending lifetimes, and responses to a product lifetime label. Results of interviews (n = 22) with Dutch consumers suggest a positive view on long‐lasting products. Nevertheless, their products’ value depreciated during their lifetimes. Consumers consider themselves unable to estimate how long products should last, which can be detrimental as low expectations tend to negatively influence actual lifetimes. Also, use intensity and consumers’ care(less) behavior influence the lifetime. To extend product lifetimes, consumers often disregard the option of repairing malfunctioning products. They have limited knowledge and ability, and believe repair provides poor value for money. Lifetime extension can also be hindered by market‐related factors, such as convenient replacement services, new technological developments, and (attractive) deals. We suggest a product lifetime label should contain relevant and reliable information; furthermore, we recommend including (extended) warranty information. When information about repairability is included, potential negative responses should be considered. Finally, raising awareness about the environmental impact of short‐lived products via a label may have a positive effect but requires more research attention.

Validation of a balancing model based on master-slave battery management system architecture

The battery management system (BMS) performs the monitoring and control of the charging/discharging process of the cell, state of charge estimation, battery safety and protection, state of health estimation, cell balancing, and thermal management. These control operations ensure accurate, safe, and reliable operating conditions, individual cell damage on battery string, and increase the cell life. Battery balancing is one of the key technologies in the BMS, which affects the actual usable capacity range, performance, and lifetime of the entire battery module. However, it is difficult to evaluate or compare the performance of the overall BMS under the multi-series battery module structure. Most of the proposed battery energy storage system (ESS) models focus on energy distribution and system estimation (microgrid or renewable energy). This study develops a balancing model for estimating the balancing performance of the BMS. A Master-Slave BMS (MS-BMS) is proposed to validate the balancing model. The Master and Slaves of the BMS employed a traditional flyback converter with a MOSFET switching array and bidirectional flyback converters with photoMOS arrays, respectively, to perform the balancing behavior. The balancing skill, balancing circuit power, equalization speed, control simplicity, modularization simplicity, and cost has been considered in designing the proposed BMS. The simulation results are verified with the experimental results, which are then compared with the balancing model's results under the five balancing conditions, and the average absolute error of the balancing duration results is 3.12%. The performance of the proposed BMS is also compared with the existing modular BMS architecture, which validates the advantages of the proposed BMS including equalization speed, control simplicity, modularization simplicity, and cost.

Ultra-high vacuum compatible full metal atom beam shutter for optical lattice clocks.

We developed a shutter driven by a solenoid to switch on/off the atomic beam of optical lattice clocks developed at KRISS [C. Y. Park etal., Metrologia 50, 119 (2013), S. Lee etal., New J. Phys. 18, 033030 (2016), H. Kim etal., Jpn. J. Appl. Phys. 56, 050302 (2017), and H. Kim etal., Metrologia 58, 055007 (2021)]. The shutter design was focused on long lifetime and compatibility with an ultra-high vacuum (UHV) environment. Thus, the solenoid was designed to be easily installed and removed from the air-side of a CF flange of the shutter. The flag in the vacuum-side moves only with the simple spring action of a sheet of a metal plate without any frictional movement of mechanical parts. All parts in the vacuum-side were made of metals (stainless steel and pure iron) to be baked over the temperature of 200 °C for UHV. The flag head of the shutter displaces up to 10mm (5mm) with a response time of 50 (30ms) and 80ms (10ms) for the opening-action and the closing-action, respectively. The lifetime was tested up to 6 × 106 cycles with no performance degradation. We expect the actual lifetime to be much longer than this by virtue of its friction-free design.

Dynamics and lifetimes of resonant phonons in the quasiparticle and nonquasiparticle regimes

The dynamics and lifetimes of a phonon with model resonant interactions from the quasiparticle to nonquasiparticle regime were investigated employing Green's function and the Green-Kubo method. In the weak-coupling case, the dynamics of the resonant phonon are analogous to a damped harmonic oscillator and its lifetime $\ensuremath{\tau}$ is in accordance with the standard phonon transport theory $\ensuremath{\tau}=\frac{1}{2\mathrm{\ensuremath{\Gamma}}}$ ($\mathrm{\ensuremath{\Gamma}}$ being the imaginary part of phonon self-energy). In the strong-coupling nonquasiparticle regime, however, the resonant phonon ``propagates'' in a complex form of wave packets and the actual phonon lifetime ${\ensuremath{\tau}}_{\mathrm{GK}}$ as determined from the Green-Kubo formula significantly deviates from the standard $\ensuremath{\tau}=\frac{1}{2\mathrm{\ensuremath{\Gamma}}}$ relation. Taking the four-phonon resonant ${\mathrm{AgCrSe}}_{2}$ and three-phonon resonant PbSe model systems as examples, the phonon nonquasiparticle dynamics and their lifetimes in real materials are further investigated by first-principle calculations. Substantial discrepancies between ${\ensuremath{\tau}}_{\mathrm{GK}}$ and $\ensuremath{\tau}$ are found for the strongly resonant phonons at high-symmetrical points in both materials. Meanwhile, the lifetime ${\ensuremath{\tau}}_{\mathrm{GK}}$ of the phonons that are not subjected to resonant phonon interactions almost recovers to the conventional theoretical result $\ensuremath{\tau}$ despite the non-Lorentzian spectral feature of these phonons. It is suggested that $\ensuremath{\omega}{\ensuremath{\tau}}_{\mathrm{GK}}$, instead of the conventional $\ensuremath{\omega}\ensuremath{\tau}$, can be applied as a criterion to distinguish phonon quasiparticles and nonquasiparticles in addition to the phonon spectral functions.

BiPO4-coated carbon microtube electrodes: preparation and characterization of their properties and electrocatalytic degradation of methylene blue.

Bismuth phosphate (BiPO4), a very attractive candidate for organics electrodegradation, harbors tremendous potential on removing contaminants from water. Here, four carbon microtube electrodes were prepared from corncob, each coated with BiPO4 by a different method to study the electrodegradation of methylene blue (MB). A thorough insight into the composite features of four electrodes was characterized. Better reversibility and electrocatalytic activity of the fourth electrode (BCC4) prepared by digital signal generator was presented with a current density of 5.71mAcm-2 at a potential of 1.6V vs Ag/AgCl. The electrochemical impedances and actual lifetime of BCC4 were 125Ω and 833h, respectively. The effectiveness of each kind of BiPO4/carbon electrode was preliminarily evaluated by analyzing the actual conversion rate of the MB concentration, which confirms MB electrodegradation by the BiPO4/carbon electrode was mainly dominated by the hydroxyl radical oxidation. The mass transfer rate was increased by carbon microtube; thereby, electrocatalysis of BiPO4/carbon electrode increased as revealed by an increase in the MB degradation rate. The rate constants k obtained for the degradation of MB by BiPO4/carbon electrode at 20℃ was 0.0046mM-1s-1, which was 11 times than that of BiPO4. The diffusion layer was decreased by carbon microtube, resulting in MB electrodegradation rate increased. The BiPO4 coated on the surface of the carbon microtube electrodes strengthened their electrocatalytic performance, which shed new light on effective selection of suitable carbon electrode for degradation of organics. Therefore, BiPO4/carbon electrode could be potentially applied in the electrodegradation of organic pollutants.

Fe3O4/TiO2/Graphene Hybrid Nanocomposite to Improve the Lifespan of Distribution Transformers

The actual lifetime of a transformer is between 30-50 years, while a foundation can be in service for 100 years. The aim of this research is to get the exact remaining lifetime of the transformers and to suggest a method to improve it. Hybrid nanoparticles are used to improve the thermal properties and dielectric strength of transformer oil. Titanium oxide (TiO2), Iron oxide (Fe3O4), and Graphene is used in specific concentration to prepare the hybrid nanoparticles. Energy Dispersive X-Ray Analysis (EDX), X-Ray Diffraction Analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR) are carried out to know whether the nanoparticles are properly synthesized. Initially Infrared thermography analysis using Fluke TiX-580 is being carried out to measure the surface temperature of the transformers and transformers under analysis are grouped. Nanofluid Transformer oil is prepared and Break Down Voltage (BDV) Test is taken to analyse the strength. Transformers are filled with nanofluid transformer oil and Infrared Thermography analysis is performed again to analyse the surface temperature. It is showing that lifetime of transformers is increased from 6 to 8% after using nanofluid transformer oil.

The Nallur Drama Festival Plays Energetically Performed the Stories of the People Affected by the War in Sri Lanka

Theatrical performances are not real, but a unique creation of real-life, It consists of two aspects, which are visual (Optical) and audible (acoustic). Both aspects take place in performing time and make a dramatic piece of real life. It is performed only for a limited time. It starts at a certain moment and then lasts and ends at another certain time. There is an actual real lifetime transformed as dramatic time. Then spectators are in real-time and dramatic time at the same time. In North Sri Lankan plays are produced by the stories of war-affected people. Since 2002, the Active Theatre Movement has brought many war-affected people’s stories to the theatre. The personal story expresses the form of effective social relationships, and gives many meanings, because those stories are complex, interconnected, and contradictory, a story performed by the human body is an expression of cultural conflict. Active Theatre Movement worked with no of war-affected people’s stories, like people who have been displaced and homeless for twenty years, struggling people resettled on their own lands after two decades, people suffering from war, not being able to live on their own lands, families lost their property and lives due to war, poverty, land becoming barren, deliberate people being evicted, etc. These factors influence the real life of North Srilanka. These stories have been the theme of the Tamil theatre in the last three decades. When conflict and oppression seem overwhelming, drama can offer hope. Tamil theatre relies on the real stories of the people. It allows people to imagine how struggles and situations can be overcome. This paper employed the Performance as a research method and take advantage of the author’s direct observations and participation Information was also obtained from actors and spectators. The paper concludes that when performing their own stories were very powerful and presented with extraordinary energy even though they are non-actors.