• International Journal of Automotive Technology
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• v.7 no.3
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• pp.245-249
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• 2006

Accelerated aging of engine exhaust system components such as catalytic converters are traditionally performed using an engine/dynamometer test stand. $SwRI^{(R)}'s\;FOCAS^{(R)}$ system reduces or eliminates many of the engine based aging limitations. This paper will describe several studies. These include: 1) replication of engine based catalyst aging cycles with added precision and dependability; 2) catalyst aging with and without lubricating oil effects; 3) effects of lubricant phosphorus on catalyst performance; and 4) the potential to thermally age components beyond the capabilities of engine based systems. The first study includes the development of the SwRI FOCAS system to run programmed aging conditions with or without lubricating oil. A description of the subsystems is given. The second two studies used the SwRI FOCAS system to age catalysts. One study compared thermal-only aging using of the SwRI FOCAS system with equivalent aging on a traditional engine/dynamometer test stand. The other study examined the effect on catalyst performance of two lubricating oils containing different levels of phosphorus, and compared the results to field data generated using the same oils in a fleet of vehicles.

• BMB Reports
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• v.52 no.1
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• pp.13-23
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• 2019

Aging is accompanied by a time-dependent progressive deterioration of multiple factors of the cellular system. The past several decades have witnessed major leaps in our understanding of the biological mechanisms of aging using dietary, genetic, pharmacological, and physical interventions. Metabolic processes, including nutrient sensing pathways and mitochondrial function, have emerged as prominent regulators of aging. Mitochondria have been considered to play a key role largely due to their production of reactive oxygen species (ROS), resulting in DNA damage that accumulates over time and ultimately causes cellular failure. This theory, known as the mitochondrial free radical theory of aging (MFRTA), was favored by the aging field, but increasing inconsistent evidence has led to criticism and rejection of this idea. However, MFRTA should not be hastily rejected in its entirety because we now understand that ROS is not simply an undesired toxic metabolic byproduct, but also an important signaling molecule that is vital to cellular fitness. Notably, mitochondrial function, a term traditionally referred to bioenergetics and apoptosis, has since expanded considerably. It encompasses numerous other key biological processes, including the following: (i) complex metabolic processes, (ii) intracellular and endocrine signaling/communication, and (iii) immunity/inflammation. Here, we will discuss shortcomings of previous concepts regarding mitochondria in aging and their emerging roles based on recent advances. We will also discuss how the mitochondrial genome integrates with major theories on the evolution of aging.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.345-352
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• 2012

Purpose: The age-hardening mechanism of an Au-Ag-Cu-Pt-Zn alloy for crown and bridge fabrication was investigated by means of hardness test, X-ray diffraction study and field emission scanning electron microscopic observation. Methods: Before hardness testing, the specimens were solution treated and then were rapidly quenched into ice brine, and were subsequently aged isothermally at $400-450^{\circ}C$ for various periods of time in a molten salt bath and then quenched into ice brain. Hardness measurements were made using a Vickers microhardness tester. The specimens were examined at 15 kV using a field emission scanning electron microscope. Results: By the isothermal aging of the solution-treated specimen at $450^{\circ}C$, the hardness increased rapidly in the early stage of aging process and reached a maximum hardness value. After that, the hardness decreased slowly with prolonged aging. However, the relatively high hardness value was obtained even with 20,000 min aging. By aging the solution-treated specimen, the f.c.c. Au-Ag-rich ${\alpha}_0$ phase was transformed into the Au-Ag-rich ${\alpha}_1$ phase and the AuCu I ordered phase. Conclusion: The hardness increase in the early stage of aging process was attributed to the formation of lattice strains by the precipitation of the Cu-rich phase and then subsequent ordering into the AuCu I-type phase. The decrease in hardness in the later stage of aging process was due to the release of coherency strains by the coarsening of tweed structure in the grain interior and by the growth and coarsening of the lamellar structure in the grain boundary. The increase of inter-lamellar space contributed slightly to the softening compared to the growth of lamellar structure toward the grain interior.

• Journal of Applied Reliability
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• v.7 no.4
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• pp.163-172
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• 2007

Phenomenon, such as hardening, cracking or breaking etc.. of PVC tape for wiring harness by aging were detected on driven automobile in field. Hardening or cracking of PVC tape were confirmed decline of elongation by surrounding stress. The accelerated heat aging test was carried out applying temperature most important factor of aging, and then deduced an equation of useful life using arrhenius model. Prediction method of useful life of PVC tape was developed using miner rule calculating damage value by thermal energy classified temperature by matching deduced equation of useful life and measured temperature value on driven automobile in field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.88-91
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• 1993

In this study 9.5/65/35 PLZT was selected which has the excellent quadratic electro-optic property and slim-loop. It was fabricated by the methods of vacuum hot-pressing and sintering. The electrode of color filter was evaporated using the interdigital type masks. Hysteresis and transmission characteristics were measured. The coercive field and the nontransmited field were correlative. Aging effect was measured according to time at same temperature. Wavelengths of RGB were chosen 700[nm] for red, 545[nm] for green and 435[nm] for blue by the standard of the Commission Internationale del Eclaiage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.398-407
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• 2021

Firefighters (who are responsible for people's safety) have one of the jobs that are expected to have problems due to aging in the workforce. An increase in the average age of firefighters can lead to serious social problems. The aim of this study is to survey firefighters in Jeollanam-do about their awareness of aging in firefighters, and to propose a plan to prepare them for aging through investigation and analysis of work problems that may occur due to an aging workforce. The survey shows that the higher the age group, the higher the awareness of aging firefighters, and the higher the total work experience and internal/external work experience, the higher the awareness of aging. As a plan to solve various problems that may arise from aging in firefighters, regular operation of physical fitness promotion programs, field work, job rotation, and managerial measures (such as a change of position to an administrative department) are prepared, and drone or robot technology is used. These solutions include the introduction of applied high-tech technologies to firefighting activities, establishment of retirement management policies, and preparation of plans to revitalize the connection to private employment. In order to maximize the applicability of the field, government institutional plans and preparations are essential.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.469-472
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• 2004

There have been numerous accelerated aging laboratory tests for evaluating suitability of polymeric materials and devices. Aging test for materials and its full scale device has been conducted, but poor correlation of aging test such as service experience were observed. Service experience plays a key role in the utility section of composite insulators. A meaningful and reliable accelerated aging test is needed for evaluating composite insulator. During the service these insulators are subjected to aging stress such as humidity, pollution, and electrical field, and erosion and tracking of the weathershed occurs. This paper presents the criteria of reliability evaluation and evaluation facilities for 22.9 kV suspension composite insulator. We adopt the criteria of reliability evaluation consist of two test methods. One is CEA tracking wheel test for examining the tracking and erosion performance of composite insulator. The other is multi-stress aging test for examining effects of environmental factors such as UV, temperature, humidity, etc on composite insulator.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.284-289
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• 2014

The effects of additives (Nb, Bi and Cr) on the microstructure, varistor properties, and aging behavior of V/Mn/Co/ La/Dy co-doped zinc oxide ceramics were systematically investigated. An analysis of the microstructure showed that all of the ceramics that were modified with various additives were composed of zinc oxide grain as the main phase, and secondary phases such as $Zn_3(VO_4)_2$, $ZnV_2O_4$, and $DyVO_4$. The $Bi_2O_3$-modified samples exhibited the lowest density, the $Nb_2O_5$-modified sample exhibited the largest average grain size, and the $Cr_2O_3$-modified samples exhibited the highest breakdown field. All additives improved the non-ohmic coefficient (${\alpha}$) by either a small or a large margin, and in particular an $Nb_2O_5$ additive noticeably increased the non-ohmic coefficient to be as large as 36. The $Bi_2O_3$-modified samples exhibited the highest stability with variation rates for the breakdown field and for the non-ohmic coefficient (${\alpha}$) of -1.2% and -26.3%, respectively, after application of a DC accelerated aging stress of 0.85 EB/$85^{\circ}C$/24 h.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.105-109
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• 2007

Aging society appears immediate social problem in Korea. Housing for aging is required independent and comfortable housing life to live considering about feature of elderly. It is necessary field to prepare. Aged person who suffers the aging process several stages gets changing weak, so living environment is important aging person aspect of social, psychological and physical point. Finally, aged person living together requires facilities for the naturally communicating and active things. Community of aged person required organization of space for keeping independence and connection with each other. According to space of community, housing for aging should have a different access route. In conclusion, congregate housing of the elderly should be planed organization of space to be solved anxiety and tension and to be aware of joining the community.

• Nuclear Engineering and Technology
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• v.29 no.5
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• pp.361-367
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• 1997

The phase separation in ferrite phase of duplex stainless steel is the primary cause of thermal aging embrittlement of the LWR primary pressure boundary components. In this study the phase separation of simulated duplex stainless steel was detected by Mossbauer spectroscopy and magnetic property analysis by VSM(Vibrating Specimen Magnetometer). The simulated duplex stainless steels, Fe-Cr binary, Fe-Cr-Ni ternary, and Fe-Cr-Ni-Si quarternary allots, were aged at 370 and 40$0^{\circ}C$ up to 5,340 hours. It was observed from Mossbauer spectra analysis that internal magnetic field increases with aging time and from VSM that the specific saturation magnetization and Curie temperature increase with aging time. These result are indicative that phase separation into Fe-rich region and Cr-rich region is caused by thermal aging in the temperature range of 370~40$0^{\circ}C$ In cases of specimens containing Ni, the increase of specific saturation magnetization is much higher. This implies that Ni seems to promote Fe-Cr interdiffusion, which accelerates the phase separation into Fe-rich $\alpha$ phase and Cr-rich $\alpha$' phase.