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Статті в журналах з теми "Local water aging"
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Fischer, Joerg, Reinhold Lang, Patrick Bradler, Paul Freudenthaler, Wolfgang Buchberger, and Susan Mantell. "Global and Local Aging in Differently Stabilized Polypropylenes Exposed to Hot Chlorinated Water with and without Superimposed Mechanical-Environmental Loads." Polymers 11, no. 7 (July 8, 2019): 1165. http://dx.doi.org/10.3390/polym11071165.
Повний текст джерелаАнотація:
The influence of chlorinated water on the global and local aging behavior of polypropylene (PP) was investigated for three differently stabilized PP grades consisting of the same PP base polymer. While one of the PP grades contained only a processing stabilizer (PP-S0), the other two were modified with a primary phenolic antioxidant (PP-S1) and a combination of a primary phenolic antioxidant and a hindered amine stabilizer (PP-S3). To study global aging effects, micro-sized specimens were pre-exposed to chlorinated water (5 mg/L free chlorine) at 60 °C for up to 750 h. Over the entire exposure period, significant material aging was detected by monitoring a continuous decrease in stabilizer content, oxidation induction temperature, mean molar mass, and mechanical strain at break. In terms of aging resistance and ultimate mechanical performance, PP-S1 was found to outperform the other two material formulations under these test conditions. Moreover, superimposed mechanical-environmental fatigue tests with cracked round bar specimens were carried out with the three PP grades in non-chlorinated (0 mg/L free chlorine) and chlorinated (5 mg/L free chlorine) water at 80 °C and 95 °C to study local crack tip aging effects. While the fatigue crack growth resistance substantially deteriorated for all three materials in chlorinated water, a significantly stronger effect was found for the higher temperature, with crack growth rates at a given stress intensity factor range in chlorinated water being ca. 30 to 50 times faster than in non-chlorinated water, depending on the material. Molar mass measurements of material samples taken from various positions of the tested CRB specimens provided clear evidence of enhanced local crack tip aging due to the chlorinated water environment.
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Lee, Chi-Yuan, Chia-Hung Chen, Guo-Bin Jung, Shih-Chun Li, and Yi-Zhen Zeng. "Internal Microscopic Diagnosis of Accelerated Aging of Proton Exchange Membrane Water Electrolysis Cell Stack." Micromachines 11, no. 12 (December 4, 2020): 1078. http://dx.doi.org/10.3390/mi11121078.
Повний текст джерелаАнотація:
The hydrogen production reaction of the proton exchange membrane (PEM) water electrolysis cell stack is the reverse reaction of the fuel cell, but the water electrolysis operation requires high pressure, and the high pressure decomposes hydrogen molecules, thus aging or causing failure in the water electrolysis cell stack. In addition, there are five important physical parameters (current, voltage, flow, pressure and temperature) inside the water electrolysis cell stack, which can change the performance and shorten the life of the cell stack. However, the present techniques obtain data only by external simulation or single measurement; they cannot collect the internal real data in operation instantly and accurately. This study discusses the causes for aging or failure, and develops an internal real-time microscopic diagnosis tool for accelerated aging of the PEM water electrolysis cell stack. A flexible integrated (current, voltage, flow, pressure and temperature) microsensor applicable to the inside (high voltage and electrochemical environment) of the PEM water electrolysis cell stack is developed by using micro-electro-mechanical systems (MEMS) technology; it is embedded in the PEM water electrolysis cell stack for microscopic diagnosis of accelerated aging, and 100-h durability and reliability tests are performed. The distribution of important physical parameters inside the PEM water electrolysis cell stack can be measured instantly and accurately, so as to adjust it to the optimal operating conditions, and the local aging and failure problems are discussed.
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Lee, Chi-Yuan, Chia-Hung Chen, Hsian-Chun Chuang, Hsiao-Te Hsieh, and Yen-Chen Chiu. "Long-Acting Real-Time Microscopic Monitoring Inside the Proton Exchange Membrane Water Electrolyzer." Sensors 23, no. 12 (June 15, 2023): 5595. http://dx.doi.org/10.3390/s23125595.
Повний текст джерелаАнотація:
The proton exchange membrane water electrolyzer (PEMWE) requires a high operating voltage for hydrogen production to accelerate the decomposition of hydrogen molecules so that the PEMWE ages or fails. According to the prior findings of this R&D team, temperature and voltage can influence the performance or aging of PEMWE. As the PEMWE ages inside, the nonuniform flow distribution results in large temperature differences, current density drops, and runner plate corrosion. The mechanical stress and thermal stress resulting from pressure distribution nonuniformity will induce the local aging or failure of PEMWE. The authors of this study used gold etchant for etching, and acetone was used for the lift-off part. The wet etching method has the risk of over-etching, and the cost of the etching solution is also higher than that of acetone. Therefore, the authors of this experiment adopted a lift-off process. Using the flexible seven-in-one (voltage, current, temperature, humidity, flow, pressure, oxygen) microsensor developed by our team, after optimized design, fabrication, and reliability testing, it was embedded in PEMWE for 200 h. The results of our accelerated aging test prove that these physical factors affect the aging of PEMWE.
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Guan, X. H., C. Shang, S. M. Yu, and G. H. Chen. "Exploratory study on reusing water treatment works sludge to enhance primary sewage treatment." Water Supply 4, no. 1 (February 1, 2004): 159–64. http://dx.doi.org/10.2166/ws.2004.0019.
Повний текст джерелаАнотація:
This paper focused on an exploratory study on reusing waste sludge of a local water treatment works (referred to as “alum sludge”) to enhance the removal of both SS (suspended solids) and COD (chemical oxygen demand) from sewage. Laboratory jar tests were conducted using the raw sewage and the alum sludge taken from a local sewage treatment works with variations in sludge dosages, aging times and pH conditions. It has been found that adding alum sludge at dosage around 20 mg/l as Al to the sewage can increase the SS removal by more than 20% and the COD removal by at least 15%, compared with the control tests without alum sludge addition. The pH of sewage, adjusted from 5 to 9, had little impact on the SS and COD removal induced by the alum sludge. However, the alum sludge aging time substantially affected the SS and COD removal. Experiment results suggested that sweep flocculation and physical adsorption play the key roles in enhancing both SS and COD removal from the raw sewage.
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Andrew, J. Jefferson, Vellayaraj Arumugam, and Hom N. Dhakal. "Effect of Intra-Ply Hybrid Patches and Hydrothermal Aging on Local Bending Response of Repaired GFRP Composite Laminates." Molecules 25, no. 10 (May 16, 2020): 2325. http://dx.doi.org/10.3390/molecules25102325.
Повний текст джерелаАнотація:
This study investigates the influence of intra-ply hybrid patches and hydrothermal aging on the indentation properties of patch repaired GFRP composites. Fabrics with various proportions of glass and Kevlar fibers were employed as the patches to achieve enhanced mechanical properties by hybridizing Kevlar and glass fibers together. Hydrothermal aging behavior of repaired composite laminates modified with water-resistant glass fibers in the outer layers was further investigated. Specimens were immersed in an environmental chamber containing seawater at temperatures of 30 (ambient), 50, and 70 °C until up to saturation. Damage mechanisms of repaired laminates were monitored using real-time acoustic emission (AE) technique. The experimental results showed that specimens repaired with 50G:50K patches offered superior performance than the virgin specimens. The hydrothermal aging effect on indentation behavior of the modified repaired specimens showed a considerable reduction in indentation properties, with higher strength retention exhibited by the repaired specimens modified with chopped glass fibers compared to the particulate fibers.
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Qin, Feng, Wenchao Zhang, Mingzi Zhang, Xiao Long, Loubin Si, Zhenjiang Li, Jiuzuo Huang, and Xiaojun Wang. "Adipose-Derived Stem Cells Improve the Aging Skin of Nude Mice by Promoting Angiogenesis and Reducing Local Tissue Water." Aesthetic Surgery Journal 41, no. 7 (January 11, 2021): NP905—NP913. http://dx.doi.org/10.1093/asj/sjab001.
Повний текст джерелаАнотація:
Abstract Background Adipose-derived stem cells (ASCs) are considered promising cells for skin rejuvenation. However, whether the angiogenetic effect of ASCs plays an important role in the treatment of aging skin and its influence on skin tissue remain elusive. Objectives The aim of this study was to evaluate the effect of ASCs on angiogenesis and local tissue water (LTW) in the aging skin of nude mice. Methods Twelve nude mice were randomly divided into a UVB-induced photoaging group and a natural aging group. After the mouse model had been established, ASCs and phosphate-buffered saline (PBS) were then each injected into different sides of the dorsal skin of the mice. Blood perfusion and LTW content were measured. After 7 weeks, mice were killed, and skin samples were collected to measure the thickness of the dermis, the density of the capillaries, and the expression of angiogenic growth factors. Results ASC therapy significantly increased the thickness of the dermis, the number of capillaries, and the expression of some angiogenic growth factors (vascular endothelial growth factor, insulin-like growth factor 1, and epidermal growth factor). At 7 weeks after injection, blood perfusion was significantly higher on the side injected with ASCs than on the side injected with PBS. LTW content was increased in the PBS-injected side, but the ASC-injected side showed no significant changes over time. Conclusions ASCs increased dermal thickness, promoted angiogenesis, and reduced LTW content in the skin of photoaging mice, providing a potential clinical therapy for skin rejuvenation.
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Zhai, Yan Wei, Chang Wu Liu, and Xina Xian Zhai. "Research on Main Problems and their Countermeasures on Chinese Small Hydropower Development." Applied Mechanics and Materials 295-298 (February 2013): 1889–93. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.1889.
Повний текст джерелаАнотація:
The constructions of small hydropower stations play an important role in improving local energy structure, development of corporations, agricultural and environmental melioration, and improving living standard of local people. Thus, studying status at small hydropower stations of China and existed problems in their development has a practical significance. With investigation data, the paper comprehensively analyzed running status of the stations, equipment aging in their development, lower utilized water resources, backward management, and disordered exploitation, etc. Therefore, the authors put forward the stations need to be technically reformed, perfecting management, professional training and so on, so that utilization efficiency on water resources could be continually improved.
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Kim, Taehyeon, Jihoon Shin, Jinseok Hyung, Kibum Kim, Jayong Koo, and YoonKyung Cha. "Willingness to Pay for Improved Water Supply Services Based on Asset Management: A Contingent Valuation Study in South Korea." Water 13, no. 15 (July 26, 2021): 2040. http://dx.doi.org/10.3390/w13152040.
Повний текст джерелаАнотація:
The pressure on water infrastructure has increased due to an increase in the number of aging water pipes. Aging pipes are prone to failure, causing significant financial losses and service disruptions. The increasing number of aged pipes and limited budget for pipe rehabilitation or replacement necessitates water infrastructure asset management to ensure sustainable water supply services. In this study, contingent valuation was used to estimate the willingness to pay (WTP) and value improved water supply services through the implementation of asset management. To estimate the WTP at the individual and county levels, we performed a nationwide survey including eight provinces and 24 counties/cities with distinct water supply service performances. At the individual level, the median WTP estimated using the double-bounded dichotomous choice model was 249.50 KRW/month (0.22 USD/month). The results showed that high-level satisfaction of customers with water supply services and positive price perception of water bills resulted in a high WTP. At the county level, decreasing water supply service performances were associated with a low WTP, indicating that proper interventions by local utilities are required to achieve sustainable water supply services. Our results provide a quantitative basis for decision-making in implementation of water infrastructure asset management.
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Bao, Keyu, Rushikesh Padsala, Daniela Thrän, and Bastian Schröter. "Urban Water Demand Simulation in Residential and Non-Residential Buildings Based on a CityGML Data Model." ISPRS International Journal of Geo-Information 9, no. 11 (October 28, 2020): 642. http://dx.doi.org/10.3390/ijgi9110642.
Повний текст джерелаАнотація:
Humans’ activities in urban areas put a strain on local water resources. This paper introduces a method to accurately simulate the stress urban water demand in Germany puts on local resources on a single-building level, and scalable to regional levels without loss of detail. The method integrates building geometry, building physics, census, socio-economy and meteorological information to provide a general approach to assessing water demands that also overcome obstacles on data aggregation and processing imposed by data privacy guidelines. Three German counties were used as validation cases to prove the feasibility of the presented approach: on average, per capita water demand and aggregated water demand deviates by less than 7% from real demand data. Scenarios applied to a case region Ludwigsburg in Germany, which takes the increment of water price, aging of the population and the climate change into account, show that the residential water demand has the change of −2%, +7% and −0.4% respectively. The industrial water demand increases by 46% due to the development of economy indicated by GDP per capita. The rise of precipitation and temperature raise the water demand in non-residential buildings (excluding industry) of 1%.
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Kuipers, Nathan T., Charity L. Sauder, Matthew L. Kearney, and Chester A. Ray. "Interactive effect of aging and local muscle heating on renal vasoconstriction during isometric handgrip." American Journal of Physiology-Renal Physiology 297, no. 2 (August 2009): F327—F332. http://dx.doi.org/10.1152/ajprenal.00165.2009.
Повний текст джерелаАнотація:
The purpose of the study was to determine the interactive effect of aging and forearm muscle heating on renal vascular conductance and muscle sympathetic nerve activity (MSNA) during ischemic isometric handgrip. A tube-lined, water-perfused sleeve was used to heat the forearm in 12 young (27 ± 1 yr) and 9 older (63 ± 1 yr) subjects. Ischemic isometric handgrip was performed before and after heating. Muscle temperature (intramuscular thermistor) was 34.3 ± 0.2 and 38.7 ± 0.1°C during normothermia and heating, respectively. At rest, heating had no effect on renal blood velocity (Doppler ultrasound) or renal vascular conductance in either group (young, n = 12; older, n = 8). Heating compared with normothermia caused a significantly greater increase in renal vasoconstriction during exercise and postexercise muscle ischemia (PEMI) in both groups. However, the increase in renal vasoconstriction during heating was greater in the older compared with the young subjects (18 ± 3 vs. 8 ± 3%). During handgrip, heating elicited greater increases in MSNA responses in the older group (young, n = 12; older, n = 6), whereas no statistical difference was observed between groups during PEMI. In summary, aging augments renal vascular responses to ischemic isometric handgrip during heating of the exercising muscle. The greater renal vasoconstriction was associated with augmented MSNA in the older subjects.
Дисертації з теми "Local water aging"
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Țîntatu, Andreea. "Étude des mécanismes de vieillissement hydrique à l’échelle locale et de leur influence sur le comportement mécanique d’assemblages collés." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2023. http://www.theses.fr/2023ENTA0004.
Повний текст джерелаАнотація:
Le collage structural est une technique d’assemblage de plus en plus utilisée dans le milieu industriel. Dans le domaine naval, ou plus généralement maritime, en présence d’eau de mer, la prédiction de l’effet de l’humidité sur le comportement mécanique des assemblages collés est d’une importance capitale. L’objectif de cette thèse est d’étudier la diffusion de l’eau dans un matériau adhésif époxy bicomposant et de proposer une stratégie de modélisation simplifiée du comportement mécanique d’un tel adhésif au sein d’un assemblage collé de type joint à simple recouvrement, en prenant en compte les effets du vieillissement hydrique. Tout d’abord, une analyse expérimentale de l’absorption d’eau dans l’adhésif est réalisée par gravimétrie et tomographie aux rayons X. La présence de pores dans le joint polymère permet une compréhension locale de l’évolution de la cinétique de diffusion, ce qui conduit au choix final et à la validation d'un modèle de diffusion. Ensuite, sur la base d’essais expérimentaux, le comportement à long terme de l’adhésif étudié est caractérisé pour différents niveaux d’absorption d’eau. Un modèle élément fini 1D enrichi est ensuite développé, permettant la modélisation multi-physique d’un joint à simple recouvrement, de manière robuste et efficace. Des simulations par éléments finis 2D et des essais sur assemblages sont enfin réalisés à des fins de validationStructural bonding is an increasingly used industrial assembly technique. In the naval, or more generally maritime, field, in the presence of seawater, the prediction of the effect of humidity on the mechanical behavior of bonded assemblies is of paramount importance. The aim of this thesis is to study water diffusion in a two-component epoxy adhesive material, and to propose a simplified modeling strategy for the mechanical behavior of such an adhesive in a single-lap joint bonded assembly, considering the effects of water aging. First, experimental analysis of water absorption in the adhesive is performed using gravimetry and X-ray tomography. The presence of pores in the polymer joint allows us to understand the local evolution of diffusion kinetics, leading to the final choice and validation of a diffusion model. Then, based on experimental tests, the long-term behavior of the investigated adhesive is characterized for different amounts of absorbed water. An enriched 1D finite element model is then developed, enabling the multi-physics modeling of a single lap joint robustly and efficiently. Finally, 2D finite element simulations and tests are carried out for validation purposes
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Francisconi, dos Rios Luciana Fávaro, Leslie Casas-Apayco, Marcela Pagani Calabria, Paulo Afonso Silveria Francisconi, Ana Flávia Sanches Borges, and Linda Wang. "Role of chlorhexidine in bond strength to artificially eroded dentin over time." Quintessence Publishing Group, 2015. http://hdl.handle.net/10757/607257.
Повний текст джерелаАнотація:
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.PURPOSE: To assess the long-term effect of a 2% aqueous chlorhexidine (CHX) solution on bond strength to artificially eroded dentin compared to sound dentin. MATERIALS AND METHODS: Flat mid-coronal dentin surfaces of extracted third molars (n = 28) were subjected only to grinding with a 600-grit SiC paper for 1 min (sound dentin S, n = 14) or additionally to erosive pH cycling with a cola-based soft-drink (eroded dentin E, n = 14). After acid etching, rinsing, and air drying, S and E were rehydrated with 1.5 μl of 2% CHX (S2%, n = 7; E2%, n = 7) or of distilled water (control SC, n = 7; EC, n = 7). Composite buildups were incrementally constructed with Filtek Z350 following Adper Single Bond 2 application. Specimens were sectioned into beams, which were subjected to microtensile testing immediately or after 6 or 12 months of aging. Fractured surfaces were observed under a digital microscope (50X magnification). Microtensile bond strength (μTBS) (MPa) was analyzed by three-way ANOVA and Tukey's tests (α = 0.05) and failure mode by the Kruskal-Wallis test (α = 0.05). RESULTS: Compared to sound dentin, eroded dentin was consistently related to lower μTBS. Immediately and after 12-month aging, the effect of CHX was insignificant, but it was significant after 6-month aging, when it conserved the bond strength to both eroded and sound dentin. The percentage of adhesive and mixed failures were equivalent, and significantly more frequent than cohesive failures, whether in dentin or in composite. CONCLUSION: The 2% CHX effect on bond strength conservation to both eroded and sound dentin was not found to be persistent.
Revisión por pares
Книги з теми "Local water aging"
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Hanson, Ardis, Peter D. Hurd, and Bruce Lubotsky Levin. Global Health. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190238308.003.0003.
Повний текст джерелаАнотація:
Global public health includes the essentials of a healthy environment, such as drinkable water, food that is plentiful and safe to eat, and waste disposal that keeps the population safe. However, global health also focuses on the prevention of disease, the promotion of healthy lifestyles, and the early detection of health problems. While these issues were once critical local problems, diseases, such as tuberculosis and cholera, illustrate the importance of a global perspective on the health of the world population. This chapter offers case studies on Haïti and Ebola, showing how national health issues not only affect a nation or a state but also the world. Discussions on global health and health equity across the developmental lifespan include interventions to address infectious diseases and lifestyle choices and the social forces of aging, poverty, and urbanization. The chapter also examines the need for increased pharmacovigilance as a global issue.
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Goldstone, Jack A. Population Movements and Security. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190846626.013.277.
Повний текст джерелаАнотація:
Population movements can affect security in a variety of ways. Aside from altering a society’s overall balance of population and physical resources, they exert a considerable influence on the institutions of society—the state, elite recruitment and social status, the military, labor organizations and peasant villages—in a way that undermines political and social order. The consequences of population movements for security can also be seen in differential population growth and migration, differential aging of different populations, and issues of resource allocation and climate change. The work of T. R. Malthus in the early nineteenth century advanced the argument that more people would put an undesirable burden on societies, and weaken them. Julian Simon turned the Malthusian argument on its head with his claim that people were the “ultimate resource,” and that the more people were around to work on solving the globe’s problems, the more likely it was that powerful solutions would be found. The debate between Malthusians, represented by Paul Ehrlich, and Cornucopians, represented by Simon, from the 1960s to the 1990s was primarily about the impact of population on economic growth. In the 1990s, a new direction emerged in the debate on population and security. This was the argument that population growth would lead to local shortages of critical resources such as farmland, water, and timber, and that these could trigger internal conflicts and even civil wars. These conflicts arise only where states and economies are relatively weak and unable to respond to population growth.
Частини книг з теми "Local water aging"
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Koynova, Teodora, Vanya Koleva, Asya P. Dragoeva, and Nikolay Natchev. "Peri-Urban National Parks as Green Spaces for Recreation." In Research Anthology on Supporting Healthy Aging in a Digital Society, 1400–1413. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-5295-0.ch079.
Повний текст джерелаАнотація:
Little is known regarding the significance for local people of peri-urban national parks as recreational areas. The main goal of the present article is to evaluate the social impact and importance of peri-urban parks for visitors as a green space for outdoor recreation. For this investigation on-site, face-to-face interviews were conducted. The main reason for visiting NP are: “to be near to nature” (64.71%), “to practice sport” (58.09%) and “relaxing” (43.38%). Spending time in NP is considered by most interviewed people to be of crucial importance both for physical (96.32%) and for mental (83.82%) health. It should be noted that high frequency of park visits was reported only by young, employed and well-educated people. Data collected shows that park management plan should encourage low-income groups (unemployed and elderly) to use outdoor recreation as a part of preventive healthcare. The access for older adults, people with disabilities and children to the park should be facilitated. Services like access to clean water, toilets and seating places must be improved. The data from the authors' survey could be useful for the peri-urban national parks development as green spaces for promoting health among all demographic groups of local inhabitants.
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Nakayama, Keiko, and Katsuhiro Sakurai. "Japanese Forest Conservation System: The Forest Environment Tax." In Sustainable Forest Management - Surpassing Climate Change and Land Degradation [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1004223.
Повний текст джерелаАнотація:
Japan is a forest-rich country, with forests covering approximately 70% of its land. It is a well-known fact that forests have a wide range of public functions, including prevention of global warming, conservation of national land, and cultivation of water sources. However, owing to low prices for domestic timber due to cheap imports, a decline in forestry workers, a lack of funds, and an aging population, poorly maintained and degraded forests have become a nationwide problem. Since the 1990s, several local governments have established funds for water resources for forest replenishment as a gesture of gratitude to upstream regions that provide a safe water supply. Furthermore, in 2003, 37 of Japan’s 47 prefectures imposed a forest environment tax on prefectural residents, starting with Kochi Prefecture. In 2019, the law of forest environment tax and forest environment transfer tax was enacted, and due to be levied as a national tax in 2024. A unique initiative in the world is a Japanese fund for forest replenishment that began out of gratitude to the upstream regions that provide water. This paper examines the funds and taxes for forest cultivation in Japan, focusing on how they were introduced, accumulated, and collected.
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Dal Prete, Ivano. "The Medieval Earth." In On the Edge of Eternity, 36—C2.P58. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780190678890.003.0003.
Повний текст джерелаАнотація:
Abstract Chapter 2 discusses medieval models of the physical changes of the globe, which often entailed the possibility or “probability” of an ancient Earth. The Bible was not the only source that described the destruction of humankind by a catastrophic flood: Plato, Aristotle, Ovid, and Seneca all posited that a physically and morally “corrupt” Earth was periodically renovated by deluges of water or fire, either universal or local, occasioned by particular astral conjunctions. Scholars like Jean Buridan and Albert of Saxony deployed impressive intellectual efforts to show that new mountains could replace aging ones as they were eroded, since the absence of such a mechanism would have denied the possibility of an ancient Earth. While they could not determine when the world began, they went to great extents to demonstrate that its extreme antiquity was physically plausible as well as compatible with the faith.
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Arnesen, Tor, and Stine Kvamme. "Fritidsbygg i fjellområdet – en egen boligstruktur?" In Utmark i endring, 123–50. Cappelen Damm Akademisk/NOASP, 2021. http://dx.doi.org/10.23865/noasp.151.ch5.
Повний текст джерелаАнотація:
There are as many leisure and second homes in the mountainous region of Southern Norway as there are primary detached house residences, and since 2000, more than three second homes have been built for every detached house. The balance in housing stock between primary and second homes is rapidly shifting towards secondary homes. More than half of the second homes in the region, and practically all those built since 2000, have high technical standards (water, sewage, road access, Internet service, electricity, etc). On average they are used 60 to 90 days a year (chiefly weekends and holidays), with frequency depending on their technical standard. A recent demographic report reveals a declining and aging fixed population in the region and forecasts a continuing decline. Second homes in the region are mainly owned by those living in urban coastal areas outside the region, persons who are “invisible” in the local population analysis. A good half of all second homes, particularly the high-standard ones, are in agglomerations in outlying areas, forming a “recreational sprawl” where urban and rural residences are linked by “recreational commuting”. Covid-19 experiences, with widespread remote working from the second home, has also shown the elasticity between the two residential platforms. More than just a leisure home, the second home agglomerations may be viewed more accurately as a unique housing stock being developed in mountain areas for part-time rural community inhabitants. A new demographic approach will be necessary to monitor this aspect of the population in many modern rural societies.
Тези доповідей конференцій з теми "Local water aging"
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Nakamura, Izumi, Akihito Otani, and Masaki Shiratori. "Failure Behavior of Elbows With Local Wall Thinning Under Cyclic Load." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2950.
Повний текст джерелаАнотація:
Pressurized piping systems used in nuclear power plants are supposed to be degraded by the effects of aging. Local wall thinning is one of the defects considered to be caused in piping systems due to the effects of aging, but the failure behavior of thinned wall pipes under seismic load is still not clear. Therefore an experimental and analytical study to clarify the failure behavior of thinned wall pipes is being conducted. In this paper, the experimental results of locally thinned wall elbows under cyclic bending load are described. Displacement-controlled cyclic bending tests were conducted on elbows with local wall thinning. The test models were pressurized to 10MPa with room temperature water and were subjected to in-plane or/and out-of-plane cyclic bending load until their failures. From the tests, the failure modes of the thinned wall elbows were found to be fatigue failure at the flank of the elbow, or fatigue and buckling failure accompanied with ratchet deformation. It was also found that the life of the thinned wall elbow subjected to out-of-plane bending were extremely lower than that of the elbow without wall thinning. The failure modes and fatigue lives of elbows seemed to be affected by a ratchet phenomenon.
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Snyder, Matthew D., Tama´s R. Liszkai, and Anne Demma. "Materials Aging Degradation of Reactor Vessel Internals: Part III—Structural Evaluation and Local Finite Element Models." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77784.
Повний текст джерелаАнотація:
Pressurized water reactor (PWR) internals components can experience material aging and degradation due to irradiation. The purpose of the functionality analysis is to provide a best-estimate evaluation of the reactor internals core barrel assembly for materials degradation to see if the components retain their function. The evaluation uses an irradiated material-specific constitutive model for use in a finite element analysis [1] representing the current state of knowledge for plasticity, creep, stress relaxation, void swelling, and embrittlement. This constitutive model is a function of temperature and fluence. The analysis focuses on finding the integrated effects of material aging combined with steady-state operational characteristics of the reactor internals. In order to evaluate the potential failure mechanisms of the core barrel assembly, finite element models were developed capable of representing the complex interactions between the components. The goal of this specific analysis is to characterize the potential failure modes, spatial and chronological distribution of potential component failures for a representative model of the Babcock & Wilcox-type (B&W) designed plants. Evaluation of the reactor vessel internals for materials aging degradation involves three analytical calculations. Radiation calculations of the core provide essential information on radiation dose and heat rates of the internals. The computational fluid dynamics domain (CFD) allows evaluation of the internals temperatures through conjugate heat transfer (CHT) analysis coupled with coolant flow. Detailed structural analysis of the internals components and bolted connections is the third major physics field involved, which facilitates the development of operating stress fields within the internals. Structural analysis was performed as two parts. First, a global structural model of the core barrel assembly was used to represent the interaction of components of the core barrel assembly during 60 years of operation. The global model does not include detail of the areas of stress concentration within bolted connections. Therefore local models of selected bolts were developed. Results of both the global and local models were used as a basis for evaluating age-related effects. The description of the functionality analysis for the B&W designed RV internals is divided into three papers. Part I was presented in PVP-2008 [2] and included a description of the overall methodology with special attention to CFD-CHT evaluations. Part II, to be presented at PVP 2009 [2] describes global structural finite element models. Part III, presented in this paper, presents a description of local models of bolted connections, results, and conclusions.
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Ja´nosine´ Bi´ro´, A´gnes, Sa´ndor Ra´tkai, Ma´rton Osztheimer, Katalin Baumann-ne´ Tanits, and Sa´ndor Baranya. "Development of Component Specific Ageing Management Programmes for Mechanical Components at the NPP Paks." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77504.
Повний текст джерелаАнотація:
The plant’s current ageing management practice is based on designer’s specifications and the more than 20 years of operation and maintenance experience. This practice meets the established rules and requirements in depth. In accordance with local regulations for long term operation the implementation of a comprehensive ageing management system for a defined scope of nuclear (safety classes 1–3+) components is required. As part of the comprehensive system, type ageing management programmes (TAMP) are developed, from which component specific programmes (SAMP) shall be developed and executed for the passive components of the concerned scope. This presentation summarizes the specific ageing management programmes of the WWER main components (reactor pressure vessel, steam generator, pressurizer, main coolant pump, main circulation pipeline, main gate valve) and of some other mechanical equipment (ECCS heat-exchangers, main steamline valves, steam generator drain expander tanks and emergency feedwater pumps). The development of the SAMPs is based on the TAMPs that describe the degradation processes (low-cycle fatigue, thermal ageing, irradiation damage, stress corrosion, boric acid corrosion, wear, local corrosion, irradiation assisted stress corrosion, loosening of threaded fasteners, swelling, high-cycle fatigue, general corrosion, thermal stratification fatigue, erosion, erosion-corrosion, water hammer, ground water corrosion, microbiological corrosion, deposition). The format and content of the SAMP comply with the domestic regulatory system and essentially follow the attributes of the US NRC’s 10 element ageing management programme (scope, prevention, parameters to be inspected, detection, monitoring-trending, acceptance criteria, corrective actions, feedback, administrative control, utilization of operating experience). During programme development, the review and, based on specific aspects, the examination of compliance of each established programme (technical review plan, ISI programme, ISI acceptance standards, maintenance instructions, water chemistry programmes, operational manuals, other inspection programmes etc.) dealing with the given component and affecting its ageing management were carried out, also taking account of the Aging Management (AM) review reports produced as part of the service life extension project. On the one hand the evaluation of the SAMP confirmed the effectiveness of the programmes currently applied, from ageing management aspects, and on the other hand, the recommended developments and enhancements help establish and strengthen the Comprehensive Ageing Management system.
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Weng, Fang-Bor, Ay Su, Chun-Ying Hsu, Guo-bin Jung, Chi-Yuan Lee, Chun-Wei Li, and Wei-Mon Yan. "Experimental Investigation of Aging for Multi-Segments PEM Fuel Cell With Dynamic Loading Cycles." In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85012.
Повний текст джерелаАнотація:
The effect of humidification on aging of local membrane electrode assembly (MEA) was investigated using dynamic cycling-change output current measurements. During the investigation, the active area of MEA was divided into 8 segments from upstream to downstream. The experiment was carried out before activation and those results served as bench mark for the results obtained after activation. The results of humidification of MEA were collected from the high frequency resistance (HFR). It was found that HFR of the first region was largest due to less water humidification. With the gas flow to the downstream, the concentration of vapor and liquid water was high, the MEA was humidified and consequently the value of HFR also decreased. The flooding in the last segment was might be due to the accumulation of water. This phenomenon resulted in the undershoot of HFR curve. The HFR curve would become steady when the flooding was removed at the last segment. The experiment of dynamic output current was carried out for 450 cycles and the total time was about 150 hours. It was found that the polarization curve became steady had less differentiation between each segment after 450 cycles of dynamic output current measurements tests. The slop of cyclic voltammetry (CV) curves charts increased from region 6 to region 8. It was supposed that the water content in the MEA was less at low loading condition and the MEA become dried. But the water content was more in high loading condition. The MEA would be in the cycle of expansion and contraction during the drying and humidification exchange process. The result suggested that the membrane might be affected easily in the downstream. Besides, the surface area of catalyst would also decay the peak of CV curve due to the water flooding which might block the mass transfer resulting in fuel starvation, carbon corrosion and catalyst degradation in downstream.
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Park, Haekeum, Kibum Kim, Jinseok Hyung, Taehyeon Kim, and Jayong Koo. "Efficiency analysis and evaluation model development of water distribution system rebuilding project using DEA method." In 2nd WDSA/CCWI Joint Conference. València: Editorial Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/wdsa-ccwi2022.2022.14768.
Повний текст джерелаАнотація:
The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, while pipe aging causes water suspension accidents and the scale of such accidents is getting large. Accordingly, the Ministry of Environment has been promoting the local water distribution system rebuilding project since 2017 to build a block system, pipe network maintenance work, leak management work, etc. Related projects are being promoted. In this study, analyzed the efficiency of the improvement of the revenue water ratio according to the DEA(Data Envelopment Analysis) method-based water distribution system rebuilding project, and develop an evaluation model for the water distribution system rebuilding project using the efficiency analysis results.In this study, DEA analysis was performed by selecting 15 local governments that showed cost-effectiveness among 20 local governments that were carrying out the performance evaluation for the 2017 rebuilding project. In this study, DEA analysis was performed considering the number of DMUs secured three times or more than the sum of input and output factors suggested in Banker et al.(1984)’s previous study.The input indicators of this study are the values derived by dividing the block system construction cost, pipe network maintenance cost, leak management cost invested for the local water distribution system rebuilding project from 2017 to 2020 by the lengths of the project target water distribution pipes. As the output indicators, the rate of increase in the revenue water ratio, which was changed according to the input project cost, was applied.In addition, a project cost evaluation model was developed for the improvement of the revenue water ratio by using the optimal efficiency point derived through the efficiency analysis with the effect of improving the revenue water ratio as a calculation index. For model development, multiple regression analysis was performed according to the step-selection method that included only independent variables with high explanatory power that had an influence on the dependent variable in the regression model to develop the model.As such, in this study, the efficiency analysis of local governments performing the local water distribution system rebuilding project was performed, and a project cost evaluation model was developed to improve the revenue water ratio. It is judged that the methodology and development model used in this study can be utilized in the analysis and evaluation of the project efficiency of the additional target area of the local water distribution system rebuilding project in the future.
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Liszkai, Tama´s R., Matthew Snyder, and Anne Demma. "Materials Aging Degradation of Reactor Vessel Internals: Part II—Structural Evaluation and Global Finite Element Models." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77786.
Повний текст джерелаАнотація:
Pressurized water reactor (PWR) vessel internals components can experience material aging and degradation due to irradiation [1]. The Electric Power Research Institute (EPRI), under sponsorship of the Materials Reliability Program (MRP), developed PWR Internals Inspection and Evaluation (I&E) Guidelines mainly to support license renewal of U.S. plants [2]. The functionality analysis of reactor internals components and assemblies was one of the tools used to develop these guidelines. The purpose of the functionality analysis is to provide a best estimate evaluation of the reactor internals core barrel assembly for materials degradation and to assess whether the components retain their function. The evaluation uses an irradiated material-specific constitutive model for use in a finite element analysis representing the current state of knowledge for plasticity, creep, stress relaxation, void swelling, and embrittlement [3], 4, [5]. This constitutive model is a function of temperature and fluence. The analysis focuses on finding the integrated effects of material aging combined with steady-state operational characteristics of the reactor vessel (RV) internals. In order to evaluate the potential failure mechanisms of the core barrel assembly, finite element models were developed capable of representing the complex interactions between the components. The goal of this specific analysis is to characterize the potential failure modes, spatial and chronological distribution of potential component failures for a representative model of the Babcock & Wilcox (B&W) designed plants. Evaluation of the reactor vessel internals for materials aging degradation involves three analytical calculations. Radiation calculations of the core provide essential information on radiation dose and heat rates, due to gamma-heating, of the RV internals. The computational fluid dynamics domain (CFD) allows the evaluation of the RV internals temperatures through conjugate heat transfer (CHT) analysis coupled with coolant flow. Detailed structural analysis of the RV internals components and bolted connections is the third major analytical calculation, which facilitates the development of operating stress fields within the RV internals. Structural analysis was performed as two parts. First, a global structural model of the core barrel assembly was used to represent the interaction of components of the core barrel assembly during 60 years of operation. The global model does not include detail of the areas of stress concentration within bolted connections, therefore local models of selected bolts were developed. Results of both the global and local models were used as a basis for evaluating age-related effects. The description of the functionality analysis for the B&W designed RV internals is divided into three papers. Part I was presented in PVP-2008 [6] and included a description of the overall methodology with special attention to CFD-CHT evaluations. Part II, detailed in this paper, describes global structural finite element models. Part III, to be also presented at PVP-2009 [7], presents a description of local models of bolted connections, results, and conclusions.
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Kirchhofer, Rita, Henry Vaillancourt, Michael Garner, and Russell C. Cipolla. "Dealloying of As-Welded Microstructures in Aluminum Bronzes in Essential Cooling Water Service." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-66255.
Повний текст джерелаАнотація:
Dealloying of aluminum-bronze (Al-Brz) is a potential environmentally-induced degradation mechanism in piping systems and components exposed to marine, brackish, or raw water service. Examples of this form of degradation have been observed in ASME Code Class 3 Essential Cooling Water systems. The degradation mechanism is loss of material due to selective leaching (i.e., dealuminification) due to localized corrosion. The dealloying occurs in the eutectoid phase in binary alloys; the eutectoid consists of α + β or α + β/γ2, and is dependent on aluminum content of the alloy, cooling rate during fabrication/welding, and the presence of a local crevice for the corrosion process to concentrate. Cast components are susceptible to general dealloying but unlike them, weldments of wrought pipe have not exhibited the same extent of degradation. The dealloying process leaves micro-voids in the microstructure within the eutectoid. Leakage (weepage) will occur once dealloying has extended through the wall thickness via a network of porous transformed phase. The dealloying process also causes a reduction in mechanical strength and fracture toughness properties. A detailed metallurgical evaluation has been completed to establish a fundamental understanding of the resistance of the pipe welds to dealloying that explains the better performance of the welds versus the castings. Factors affecting the dealloying susceptibility, such as aluminum and iron content, cooling rates during the solidification process, and the resulting microstructural differences were studied and evaluated. It was found that dealloying will not penetrate into the material unless a continuous network of susceptible microstructure is present. The difference in susceptibility between castings and weldments to dealloying was also determined. The findings of this comparative evaluation were significant and are being used in the aging management program to justify continued use of aluminum bronze piping welds for extended service for both above ground and below ground (buried) piping systems.
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Che Daud, M. Faizal, Siti Nur Shaffee, and Maung Maung Myo Thant. "Novel Technology for Sand Management at Ageing Field: Cost Optimisation of Offshore Sand Handling and Disposal." In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21163-ms.
Повний текст джерелаАнотація:
Abstract Excessive sand production is synonymous with aging fields and increased water production. Some offshore fields in Malaysia produce sand in the range of tonnes per day. Conventionally, the produced sand needs to be sent onshore for treatment, increasing the OPEX for a field with an already declining production. This paper presents a newly developed technology to help operators in handling and disposal of produced sand offshore. A hybrid system of a unique mechanical agitation and the chemical solution was developed for offshore sand cleaning. The system aims to remove Oil-in-Water (OIW) and Oil-in-Sand (OIS) content according to the local regulations and requirements for offshore disposal. In the lab-scale screening, the best performing deoiling chemical for oil removal from the sand was achieved using novel chemical formulations containing surfactants with higher water affinity (hydrophilic). In the bench-scale prototype evaluation, the deoiling chemical was coupled with a mechanical system. A semi-automated, pilot-scale unit with the capacity to handle approximately 1 metric tonne of oily sand was constructed and used for further testing. In the lab stage, the sand deoiling formulation was identified and optimized. Up to bench-scale testing, only 30ppm of deoiling chemical is required to clean the field sand to OIS of <1wt% and OIW of less than 40ppm. The effectiveness of mechanical agitation and low dosage of chemical deoiling is further proven via testing using the pilot-scale unit. It has been shown that a superior cleaning quality meeting the onboard disposal specification can be achieved via this system compared to existing technology which is based on only mechanical means. An example of potential sand cleaning system integration and tie-in to an existing offshore facility with excessive sand production is also discussed in this work. The compact sand cleaning system is a novel technology to reduce OIS content, leading to reduced sand handling and disposal OPEX for aging fields.
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Glass, S. W., Leonard S. Fifield, and Mychal P. Spencer. "Transition to Online Cable Insulation Condition Monitoring." In 2021 48th Annual Review of Progress in Quantitative Nondestructive Evaluation. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/qnde2021-75014.
Повний текст джерелаАнотація:
Abstract Nuclear power plant cables were originally qualified for 40 year life and generally have not required specific test verification to assure service availability through the initial plant qualification period. However, license renewals to 60 and 80 years of operation require a cable aging management program that depends on some form of test and verification to assure fitness for service. Environmental stress (temperature, radiation, chemicals, water, and mechanical) varies dramatically within a nuclear power plant and, in some cases, cables have degraded and required repair or replacement before their qualified end-of-life period. In other cases, cable conditions have been mild and dependable cable performance confirmed to extend well beyond the initial qualified life. Most offline performance-based testing requires cables to be decoupled and de-energized for specially trained technicians to perform testing. These offline tests constitute an expensive operational burden that limits the economic viability of nuclear power plants. Although initial investment may be higher, new online test practices are emerging as options or complements to offline testing that avoid or minimize the regularly scheduled offline test burden. These online methods include electrical and fiber-optic partial discharge measurement, spread spectrum time or frequency domain reflectometry, distributed temperature profile measurements, and local interdigital capacitance measurement of insulation characteristics. Introduction of these methods must be supported by research to confirm efficacy plus either publicly financed or market driven investment to support the start-up expense of cost-effective instrumentation to monitor cable condition and assure reliable operation. This work summarizes various online cable assessment technologies plus introduces a new cable motor test bed to assess some of these technologies in a controlled test environment.
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Jenewein, Oswald. "Post-Oil Environments: Responsive Design Strategies for Coastal City-Landscapes of Oil." In 2020 ACSA Fall Conference. ACSA Press, 2020. http://dx.doi.org/10.35483/acsa.aia.fallintercarbon.20.4.
Повний текст джерелаАнотація:
This paper summarizes parts of an interdisciplinary research and design project on climate adaptation strategies on the scale of architecture and the city within the case-study territory of Corpus Christi Bay in South Texas. In particular, this paper assesses the challenges of the emerging process of re-industrialization along the Texas Coast, highlighting significant impacts of industrial growth on the city landscape of Downtown Corpus Christi, which is located directly adjacent to the industrial oil port. A proposed masterplan is shown in this paper to demonstrate how responsive design strategies may benefit post-oil city-landscapes in the age of anthropogenic climate change. The emphasis is storm-water and flood mitigation, walkability, alternative transportation, and urban place-making in response to community input related to the United Nations Sustainable Development Goals (SDGs) and the AIA Framework for Designing for Equitable Communities. Methodologically, this project builds upon a mixed-methods approach. It includes qualitative and quantitative data gathered through Participatory Action Research, a successful tool to connect the research team and students to local communities, stakeholders, and constituents. The paper suggests that this era of re-industrialization needs to be seen as a transformative process that enables the aging city landscape to adapt to both changing ecological conditions and the time after this late oil boom. Urban identity, socio-economic diversity, and healthy conditions for urban ecosystems are essential parameters to inform the development of comprehensive strategies for the built environment. The responsive design strategies shown in this paper pro- pose the implementation of an infrastructural landscape addressing these challenges. The central element of the master plan is a canal that serves multiple purposes, including disaster preparation and response infrastructure, stormwater management, and alternative transportation for inner-city and city-to-city connections, has been developed to adapt Downtown Corpus Christi to the projected ecological changes.
Звіти організацій з теми "Local water aging"
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Perera, Duminda, Vladimir Smakhtin, Spencer Williams, Taylor North, and Allen Curry. Ageing Water Storage Infrastructure: An Emerging Global Risk. United Nations University Institute for Water, Environment and Health, January 2021. http://dx.doi.org/10.53328/qsyl1281.
Повний текст джерелаАнотація:
The Report provides an overview of the current state of knowledge on the ageing of large dams –an emerging global development issue as tens of thousands of existing large dams have reached or exceeded an “alert” age threshold of 50 years, and many others will soon approach 100 years. These aged structures incur rapidly rising maintenance needs and costs while simultaneously declining their effectiveness and posing potential threats to human safety and the environment. The Report analyzes large dam construction trends across major geographical regions and primary dam functions, such as water supply, irrigation, flood control, hydropower, and recreation. Analysis of existing global datasets indicates that despite plans in some regions and countries to build more water storage dams, particularly for hydropower generation, there will not be another “dam revolution” to match the scale of the high-intensity dam construction experienced in the early to middle, 20th century. At the same time, many of the large dams constructed then are aging, and hence we are already experiencing a “mass ageing” of water storage infrastructure. The Report further explores the emerging practice of decommissioning ageing dams, which can be removal or re-operation, to address issues of ensuring public safety, escalating maintenance costs, reservoir sedimentation, and restoration of a natural river ecosystem. Decommissioning becomes the option if economic and practical limitations prevent a dam from being upgraded or if its original use has become obsolete. The cost of dam removal is estimated to be an order of magnitude less than that of repairing. The Report also gives an overview of dam decommissioning’s socio-economic impacts, including those on local livelihoods, heritage, property value, recreation, and aesthetics. Notably, the nature of these impacts varies significantly between low- and high-income countries. The Report shows that while dam decommissioning is a relatively recent phenomenon, it is gaining pace in the USA and Europe, where many dams are older. However, it is primarily small dams that have been removed to date, and the decommissioning of large dams is still in its infancy, with only a few known cases in the last decade. A few case studies of ageing and decommissioned large dams illustrate the complexity and length of the process that is often necessary to orchestrate the dam removal safely. Even removing a small dam requires years (often decades), continuous expert and public involvement, and lengthy regulatory reviews. With the mass ageing of dams well underway, it is important to develop a framework of protocols that will guide and accelerate the process of dam removal. Overall, the Report aims to attract global attention to the creeping issue of ageing water storage infrastructure and stimulate international efforts to deal with this emerging water risk. This Report’s primary target audiences are governments and their partners responsible for planning and implementing water infrastructure development and management, emphasizing adaptat