Chad A. Beaudette, Qiaomiao Tu, Mohammad Ali Eslamisaray, U. Kortshagen
Titanium dioxide in its pure wide bandgap “white” form is a non-toxic, efficient, and practical photocatalyst, but predominately absorbs light in the ultraviolet range of the spectrum. The absorption range, however, can be extended into the visible by doping with oxygen vacancies or impurities, such as nitrogen, giving the material a black or brown appearance. To date, nitrogen-doped titanium dioxide has primarily been produced with approaches that require long processing times or multi-step synthesis protocols. Here, we present a fast (timescale of tens of milliseconds) all-gas-phase process, which enables the seamless tuning of the optical properties of titanium dioxide nanoparticles from white to brown. Titanium dioxide particles were synthesized through injection of tetrakis (dimethylamido)titanium (TDMAT), argon, and oxygen into a nonthermal plasma. The positions of the electrode and oxygen inlet relative to the precursor inlet are found to strongly influence particle properties. Variation of these parameters allowed for control over the produced particle optical properties from large bandgap (white) to small bandgap (brown). In addition, the particle microstructure can be tuned from amorphous to crystalline anatase phase titanium dioxide. The photocatalytic performance was tested under solar irradiation and amorphous particles exhibit the highest degree of photocatalytic decomposition of the dyes methyl orange and methylene blue.
{"title":"Plasma-Synthesized Nitrogen-Doped Titanium Dioxide Nanoparticles With Tunable Visible Light Absorption and Photocatalytic Activity","authors":"Chad A. Beaudette, Qiaomiao Tu, Mohammad Ali Eslamisaray, U. Kortshagen","doi":"10.1115/1.4053338","DOIUrl":"https://doi.org/10.1115/1.4053338","url":null,"abstract":"\u0000 Titanium dioxide in its pure wide bandgap “white” form is a non-toxic, efficient, and practical photocatalyst, but predominately absorbs light in the ultraviolet range of the spectrum. The absorption range, however, can be extended into the visible by doping with oxygen vacancies or impurities, such as nitrogen, giving the material a black or brown appearance. To date, nitrogen-doped titanium dioxide has primarily been produced with approaches that require long processing times or multi-step synthesis protocols. Here, we present a fast (timescale of tens of milliseconds) all-gas-phase process, which enables the seamless tuning of the optical properties of titanium dioxide nanoparticles from white to brown. Titanium dioxide particles were synthesized through injection of tetrakis (dimethylamido)titanium (TDMAT), argon, and oxygen into a nonthermal plasma. The positions of the electrode and oxygen inlet relative to the precursor inlet are found to strongly influence particle properties. Variation of these parameters allowed for control over the produced particle optical properties from large bandgap (white) to small bandgap (brown). In addition, the particle microstructure can be tuned from amorphous to crystalline anatase phase titanium dioxide. The photocatalytic performance was tested under solar irradiation and amorphous particles exhibit the highest degree of photocatalytic decomposition of the dyes methyl orange and methylene blue.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80463314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Collin Ynchausti, Clark Roubicek, Joseph Erickson, Brandon Sargent, S. Magleby, L. Howell
The hexagonal twist origami pattern has characteristics that made it a candidate for next-generation deployable space arrays. It has a deployed area that is up to 3.3 times larger than the stowed area, has a single-degree-of-freedom which simplifies actuation, it is flat-foldable making flat positions possible in both stowed and deployed positions, and its rigid foldability means that its motion is enabled by rotation about distinct axes without deformation of its panels. Although the pattern shows promise for deployable systems, it cannot be directly applied with thick materials because of the self-intersection of nesting panels. This paper presents the kinematics and mechanical advantages of the hexagonal twist pattern, addresses the self-intersection problem by implementing five different thickness accommodation techniques and provides metrics for comparing thickness accommodation techniques to determine which would be best suited for a given application. The concepts are demonstrated through two applications: a deployable reflectarray antenna and a LiDAR telescope.
{"title":"Hexagonal Twist Origami Pattern for Deployable Space Arrays","authors":"Collin Ynchausti, Clark Roubicek, Joseph Erickson, Brandon Sargent, S. Magleby, L. Howell","doi":"10.1115/1.4055357","DOIUrl":"https://doi.org/10.1115/1.4055357","url":null,"abstract":"\u0000 The hexagonal twist origami pattern has characteristics that made it a candidate for next-generation deployable space arrays. It has a deployed area that is up to 3.3 times larger than the stowed area, has a single-degree-of-freedom which simplifies actuation, it is flat-foldable making flat positions possible in both stowed and deployed positions, and its rigid foldability means that its motion is enabled by rotation about distinct axes without deformation of its panels. Although the pattern shows promise for deployable systems, it cannot be directly applied with thick materials because of the self-intersection of nesting panels. This paper presents the kinematics and mechanical advantages of the hexagonal twist pattern, addresses the self-intersection problem by implementing five different thickness accommodation techniques and provides metrics for comparing thickness accommodation techniques to determine which would be best suited for a given application. The concepts are demonstrated through two applications: a deployable reflectarray antenna and a LiDAR telescope.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80728029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three geothermal systems, including single-flash, double-flash, and double-flash connected turbine flash geothermal power plants, are compared in terms of electrical power production and exergy efficiency. In the double-flash connected turbine (double-T) geothermal electrical power production systems, the outlet stream from the first steam turbine is recovered in the mixing chamber and combined with the vapor product of the second separator. The thermodynamic model for the single-flash, double-flash, and double-T geothermal systems is developed using energy and exergy balances for each component of the systems. From the thermodynamic model, the optimum flash chambers pressures, at which the electrical power production is a maximum, can be determined. It is found that, for an input geothermal source temperature of 230 °C and an input geothermal water mass flowrate of 230 kg/s, the optimum pressures for the first flash chamber are 300 kPa, 350 kPa, and 350 kPa for the single-flash, double-flash, and double-T geothermal systems, respectively. The electrical power produced in these systems at their corresponding optimum flashing pressures, respectively, are 16,000 kW, 19,500 kW, and 20,600 kW. Also, for the single-flash, double-flash, and double-T geothermal systems, the exergy efficiency at the optimum flash chamber pressures are found to be 44.2%, 47.1%, and 48.5%, respectively.
{"title":"Comparison of Thermodynamic Performances in Three Geothermal Power Plants Using Flash Steam","authors":"Aida Farsi, M. Rosen","doi":"10.1115/1.4054038","DOIUrl":"https://doi.org/10.1115/1.4054038","url":null,"abstract":"\u0000 Three geothermal systems, including single-flash, double-flash, and double-flash connected turbine flash geothermal power plants, are compared in terms of electrical power production and exergy efficiency. In the double-flash connected turbine (double-T) geothermal electrical power production systems, the outlet stream from the first steam turbine is recovered in the mixing chamber and combined with the vapor product of the second separator. The thermodynamic model for the single-flash, double-flash, and double-T geothermal systems is developed using energy and exergy balances for each component of the systems. From the thermodynamic model, the optimum flash chambers pressures, at which the electrical power production is a maximum, can be determined. It is found that, for an input geothermal source temperature of 230 °C and an input geothermal water mass flowrate of 230 kg/s, the optimum pressures for the first flash chamber are 300 kPa, 350 kPa, and 350 kPa for the single-flash, double-flash, and double-T geothermal systems, respectively. The electrical power produced in these systems at their corresponding optimum flashing pressures, respectively, are 16,000 kW, 19,500 kW, and 20,600 kW. Also, for the single-flash, double-flash, and double-T geothermal systems, the exergy efficiency at the optimum flash chamber pressures are found to be 44.2%, 47.1%, and 48.5%, respectively.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"158 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79993076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Lund, J. E. Thorsen, Steen Schelle Jensen, F. P. Madsen
Future district heating systems and technologies—also known as fourth-generation district heating—have a potentially important role to play in the green transition of societies. The implementation of fourth-generation district heating involves adjustments in the demand side to allow for low temperature supply. In order to facilitate such changes, district heating supply companies have in recent years introduced tariffs with penalties for high return temperatures and benefits for low return temperatures. This paper describes the case of a housing community of 17 buildings in their attempts to adjust to such tariffs as an integrated part of connecting to district heating. Replacing domestic hot water tanks with instantaneous heat exchangers and introducing smart meters resulted in abilities to lower the return temperature from around 40 °C to around 30 °C. However, the current design of the motivation tariffs does not yet fully compensate the consumers because the supply company provides unnecessarily high supply temperatures. Based on such efforts, this paper discusses the fairness and effectiveness of the tariffs and provides recommendations for improving them.
{"title":"Fourth-Generation District Heating and Motivation Tariffs","authors":"H. Lund, J. E. Thorsen, Steen Schelle Jensen, F. P. Madsen","doi":"10.1115/1.4053420","DOIUrl":"https://doi.org/10.1115/1.4053420","url":null,"abstract":"\u0000 Future district heating systems and technologies—also known as fourth-generation district heating—have a potentially important role to play in the green transition of societies. The implementation of fourth-generation district heating involves adjustments in the demand side to allow for low temperature supply. In order to facilitate such changes, district heating supply companies have in recent years introduced tariffs with penalties for high return temperatures and benefits for low return temperatures. This paper describes the case of a housing community of 17 buildings in their attempts to adjust to such tariffs as an integrated part of connecting to district heating. Replacing domestic hot water tanks with instantaneous heat exchangers and introducing smart meters resulted in abilities to lower the return temperature from around 40 °C to around 30 °C. However, the current design of the motivation tariffs does not yet fully compensate the consumers because the supply company provides unnecessarily high supply temperatures. Based on such efforts, this paper discusses the fairness and effectiveness of the tariffs and provides recommendations for improving them.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80257074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal energy storage (TES) coupled with nuclear energy could be a transformative contribution to address the mismatch in energy production and demand that occur with the expanding use of solar and wind energy. TES can generate new revenue for the nuclear plant and help decarbonize the electricity grid. Prior work by the authors identified two technical approaches to interface TES with nuclear. One, termed the primary cycle TES, charges and discharges the TES within the main Rankine power cycle. The second, termed the secondary cycle TES or SCTES, discharges the TES to a secondary power cycle. The present work analyzes the potential economic benefits of TES in an arbitrage market for a 1050 MWe nuclear plant. The study is the first to provide a realistic quantification of the impacts of changes in capacity factor due to use of TES on revenue and internal rate of return (IRR). The analysis is for a three-year period for peaking powers from 120% to 150% of the conventional nuclear plant for an exemplary deregulated utility represented by the Electric Reliability Council of Texas (ERCOT). The SCTES consistently provides the highest revenue and IRR. The benefits increase with increasing use of TES and variability of electricity prices. The results provide a technically sound understanding of the effects of how TES is integrated with nuclear power on economics and strong economic support for pursuing design and implementation of the SCTES.
{"title":"Nuclear Power Coupled With Thermal Energy Storage: Impact of Technical Performance on Economics in an Exemplary Electricity Grid","authors":"Fletcher Carlson, J. Davidson","doi":"10.1115/1.4053419","DOIUrl":"https://doi.org/10.1115/1.4053419","url":null,"abstract":"\u0000 Thermal energy storage (TES) coupled with nuclear energy could be a transformative contribution to address the mismatch in energy production and demand that occur with the expanding use of solar and wind energy. TES can generate new revenue for the nuclear plant and help decarbonize the electricity grid. Prior work by the authors identified two technical approaches to interface TES with nuclear. One, termed the primary cycle TES, charges and discharges the TES within the main Rankine power cycle. The second, termed the secondary cycle TES or SCTES, discharges the TES to a secondary power cycle. The present work analyzes the potential economic benefits of TES in an arbitrage market for a 1050 MWe nuclear plant. The study is the first to provide a realistic quantification of the impacts of changes in capacity factor due to use of TES on revenue and internal rate of return (IRR). The analysis is for a three-year period for peaking powers from 120% to 150% of the conventional nuclear plant for an exemplary deregulated utility represented by the Electric Reliability Council of Texas (ERCOT). The SCTES consistently provides the highest revenue and IRR. The benefits increase with increasing use of TES and variability of electricity prices. The results provide a technically sound understanding of the effects of how TES is integrated with nuclear power on economics and strong economic support for pursuing design and implementation of the SCTES.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82923101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph M. Staller, R. Craven, S. Idem, S. Munukutla, Keith Kirkpatrick, D. Benton, Susan Eisenstadt, Karsten Kopperstad, Seth Leedy, J. McHale, A. Licata, Dan Andrei
This paper describes a real-time performance monitoring method based on PTC 4-2013 for determining instantaneous heat rates for coal-fired power plants. The calculation protocol uses a modified output–loss approach applied to a control volume that closely conforms to the boiler. The largest energy balance term is the heat transfer rate to the steam, which is known accurately in real-time when the plant employs properly calibrated instrumentation. The first-law energy balance also requires a balanced combustion equation which depends on coal composition, which is not known in real-time. A periodic or alert-driven calibration utilizes an ultimate analysis of a carefully collected coal sample and historic plant data obtained during the collection time of the coal sample. This is used to calculate correction factors for the coal mass flowrate, air preheater leakage, and CO2 and SO2 concentrations at the economizer exit derived from continuous emissions monitoring systems (CEMS) measurements performed at that location. The iterative calculations required to determine the coal composition in real-time are presented. The real-time performance algorithm exhibited significant sensitivity associated with measurements of the steam heat transfer rate, which was the dominant term in the overall boiler energy balance. Other input parameters generally yielded a much lower influence on calculated heat rate. It was concluded that for optimal accuracy of the output–loss method the steam and coal mass flowrates must be measured as accurately as possible.
{"title":"A Real-Time Output–Loss Method for Monitoring Heat Rate for Coal-Fired Power Plants","authors":"Joseph M. Staller, R. Craven, S. Idem, S. Munukutla, Keith Kirkpatrick, D. Benton, Susan Eisenstadt, Karsten Kopperstad, Seth Leedy, J. McHale, A. Licata, Dan Andrei","doi":"10.1115/1.4055627","DOIUrl":"https://doi.org/10.1115/1.4055627","url":null,"abstract":"\u0000 This paper describes a real-time performance monitoring method based on PTC 4-2013 for determining instantaneous heat rates for coal-fired power plants. The calculation protocol uses a modified output–loss approach applied to a control volume that closely conforms to the boiler. The largest energy balance term is the heat transfer rate to the steam, which is known accurately in real-time when the plant employs properly calibrated instrumentation. The first-law energy balance also requires a balanced combustion equation which depends on coal composition, which is not known in real-time. A periodic or alert-driven calibration utilizes an ultimate analysis of a carefully collected coal sample and historic plant data obtained during the collection time of the coal sample. This is used to calculate correction factors for the coal mass flowrate, air preheater leakage, and CO2 and SO2 concentrations at the economizer exit derived from continuous emissions monitoring systems (CEMS) measurements performed at that location. The iterative calculations required to determine the coal composition in real-time are presented. The real-time performance algorithm exhibited significant sensitivity associated with measurements of the steam heat transfer rate, which was the dominant term in the overall boiler energy balance. Other input parameters generally yielded a much lower influence on calculated heat rate. It was concluded that for optimal accuracy of the output–loss method the steam and coal mass flowrates must be measured as accurately as possible.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85149502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The release of dispersant from an aircraft onto an oil spill is simulated using the AGDISPpro computer model, to develop a better understanding of how aircraft type, spray systems, and meteorological conditions affect the prediction of surface deposition. This model, originally developed for predicting the aerial release of pesticides for agricultural spray applications, is ideally suited to simulate the effects of aircraft type and flight condition/configuration, spray system arrangement, wind speed and direction, temperature and relative humidity (evaporation), release height, and spray application rate when spraying an oil spill. Predictions of droplet trajectories from the aircraft to the surface, drop size distributions at the release height, and deposition profiles are compared to two historical datasets for the Lockheed C-130, from field studies conducted in 1982 and 1993. This article shows that model accuracy improves from R2 = 0.411 to 0.827 with the earlier data, to R2 = 0.885 to 0.968 with the later data, most probably because of a better understanding of nozzle locations in the 1993 data. Model accuracy also appears improved when the aircraft flies in an in-wind direction, a configuration strongly recommended in the available literature.
{"title":"Predicting the Aerial Application of Dispersant Onto an Oil Spill","authors":"M. Teske, G. Whitehouse","doi":"10.1115/1.4055984","DOIUrl":"https://doi.org/10.1115/1.4055984","url":null,"abstract":"\u0000 The release of dispersant from an aircraft onto an oil spill is simulated using the AGDISPpro computer model, to develop a better understanding of how aircraft type, spray systems, and meteorological conditions affect the prediction of surface deposition. This model, originally developed for predicting the aerial release of pesticides for agricultural spray applications, is ideally suited to simulate the effects of aircraft type and flight condition/configuration, spray system arrangement, wind speed and direction, temperature and relative humidity (evaporation), release height, and spray application rate when spraying an oil spill. Predictions of droplet trajectories from the aircraft to the surface, drop size distributions at the release height, and deposition profiles are compared to two historical datasets for the Lockheed C-130, from field studies conducted in 1982 and 1993. This article shows that model accuracy improves from R2 = 0.411 to 0.827 with the earlier data, to R2 = 0.885 to 0.968 with the later data, most probably because of a better understanding of nozzle locations in the 1993 data. Model accuracy also appears improved when the aircraft flies in an in-wind direction, a configuration strongly recommended in the available literature.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80558854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A lack of knowledge acquisition (LOKA), among engineering staff members in supply firms (e.g., vendors), owner/operator utilities (e.g., licensees), and in regulatory agencies (e.g., the NRC), can impair nuclear power plant (NPP) safety in ways that can persist throughout the operating lifetime of an NPP. A LOKA occurs when experienced technical reviewers fail to pass enough information, or technology, to less-experienced technical reviewers. The existence of a LOKA, among technical reviewers, can lead to errors and omissions that can result in misleading or incomplete licensing bases. Eight examples of errors and omissions are presented, each of which is evaluated in the context of physical phenomena, logic, licensing strategy, and effects upon regulation. These errors and omissions could be attributed to several causes, one of which could be a LOKA. Reliable attribution to a LOKA or its causes is not directly addressed, since attention is focused principally upon the safety implications of errors and omissions that may possibly, but not exclusively, be due to a LOKA. The epistemology of a LOKA, which may consider training or human relations, is generally addressed in other studies, which apply to issues that affect more than the nuclear power industry. If those who design, analyze, license, operate, and regulate NPPs do not adequately understand and apply proven engineering principles, standards, and established regulations, critical thinking, and sound logical reasoning, then it could be said that a LOKA exists. A LOKA could hamper the development of defensible conclusions in safety analyses, viable licensing strategies, and fair regulatory judgments. Eight examples of errors and omissions are presented, each of which leads to a conclusion that seems to conflict with an industry standard, a federal regulation, an engineering principle or physical phenomenon, or just plain logic. The examples are generally evaluated in accordance with the requirements of a well-known, oft-cited nuclear industry standard, which is now almost half a century old. This standard was published in 1973 by the American Nuclear Society (ANS) (1973, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants, La Grange Park, IL, ANS-N18.2-1973). It expresses the fundamental principle of nuclear safety and licensing, which is applied by vendors, licensees, and regulators alike. This Standard defines nuclear safety criteria and plant design requirements for plant operating situations or events according to their expected frequencies of occurrence. Those events that have high frequencies of occurrence must not pose a danger to the public. Events that could pose the greatest danger to the public must be limited, by design, to extremely low expected frequencies of occurrence. This concept is implemented by grouping postulated plant situations (or events) into categories that are defined according to their expected frequencies of occurrence. License
在供应公司(如供应商)、业主/运营商公用事业公司(如被许可方)和监管机构(如美国核管理委员会)的工程人员中，缺乏知识获取(LOKA)可能会损害核电厂的安全，并在核电厂的整个运行寿命期间持续存在。当经验丰富的技术审查人员未能将足够的信息或技术传递给经验不足的技术审查人员时，就会发生LOKA。在技术审查人员中存在LOKA可能会导致错误和遗漏，从而导致误导性或不完整的许可基础。提出了8个错误和遗漏的例子，每个例子都在物理现象、逻辑、许可策略和对监管的影响的背景下进行了评估。这些错误和遗漏可归因于几个原因，其中一个可能是LOKA。对于LOKA或其原因的可靠归属没有直接解决，因为注意力主要集中在可能但并非完全由LOKA引起的错误和遗漏的安全影响上。LOKA的认识论可能考虑到培训或人际关系，一般在其他研究中讨论，这些研究适用于影响比核动力工业更大的问题。如果那些设计、分析、许可、运营和管理核电站的人不能充分理解和应用经过验证的工程原理、标准、既定法规、批判性思维和合理的逻辑推理，那么可以说LOKA是存在的。LOKA可能会阻碍安全性分析、可行的许可策略和公平监管判断中可辩护结论的发展。文中给出了8个错误和遗漏的例子，每一个都导致了一个似乎与行业标准、联邦法规、工程原理或物理现象或简单逻辑相冲突的结论。这些例子通常是根据一个众所周知的、经常被引用的核工业标准的要求进行评估的，这个标准现在已经有近半个世纪的历史了。该标准于1973年由美国核学会(ANS)发布(1973年，《固定压水反应堆工厂设计的核安全标准》，La Grange Park, IL, ANS- n18.2 -1973)。它表达了核安全和许可的基本原则，适用于供应商、许可证持有者和监管机构。本标准根据预期发生频率，定义核电厂运行情况或事件的核安全准则和核电厂设计要求。发生频率高的事件不得对公众构成危险。对于可能对公众构成最大危险的事件，必须有计划地控制在极低的预期发生频率之内。这个概念是通过将假定的工厂情况(或事件)分组到根据其预期发生频率定义的类别中来实现的。被许可方必须对每个类别的事件进行分析和评估，以证明事件的后果不超过该类别的指定可接受限度。此外，被许可人必须证明某些事件不会发展成更严重的事件(例如，事件将被归为更严重、后果更高的类别)，而不会同时发生独立的故障。也就是说，标准(美国核学会，1973年，《设计稳压水反应堆核电站的核安全标准》，La Grange Park, IL, ANS-N18.2-1973)要求核电站的设计方式必须不允许高频、低后果事件降级为高频、高后果事件。在示例评估中考虑的错误和遗漏可能是由于LOKA以及其他可能的原因造成的。在每个示例中，LOKA就足够了;但没有必要，以产生注意到的错误和遗漏。注意力集中在LOKA的安全含义上，而不是它的认识论。核电工业中的LOKA，包括其监管机构，正在进行中，因为它没有得到承认和补救。
{"title":"A Lack of Knowledge Acquisition Can Impair Nuclear Power Plant Safety","authors":"Samuel Miranda, Ralph Caruso","doi":"10.1115/1.4053988","DOIUrl":"https://doi.org/10.1115/1.4053988","url":null,"abstract":"\u0000 A lack of knowledge acquisition (LOKA), among engineering staff members in supply firms (e.g., vendors), owner/operator utilities (e.g., licensees), and in regulatory agencies (e.g., the NRC), can impair nuclear power plant (NPP) safety in ways that can persist throughout the operating lifetime of an NPP. A LOKA occurs when experienced technical reviewers fail to pass enough information, or technology, to less-experienced technical reviewers. The existence of a LOKA, among technical reviewers, can lead to errors and omissions that can result in misleading or incomplete licensing bases. Eight examples of errors and omissions are presented, each of which is evaluated in the context of physical phenomena, logic, licensing strategy, and effects upon regulation. These errors and omissions could be attributed to several causes, one of which could be a LOKA. Reliable attribution to a LOKA or its causes is not directly addressed, since attention is focused principally upon the safety implications of errors and omissions that may possibly, but not exclusively, be due to a LOKA. The epistemology of a LOKA, which may consider training or human relations, is generally addressed in other studies, which apply to issues that affect more than the nuclear power industry. If those who design, analyze, license, operate, and regulate NPPs do not adequately understand and apply proven engineering principles, standards, and established regulations, critical thinking, and sound logical reasoning, then it could be said that a LOKA exists. A LOKA could hamper the development of defensible conclusions in safety analyses, viable licensing strategies, and fair regulatory judgments. Eight examples of errors and omissions are presented, each of which leads to a conclusion that seems to conflict with an industry standard, a federal regulation, an engineering principle or physical phenomenon, or just plain logic. The examples are generally evaluated in accordance with the requirements of a well-known, oft-cited nuclear industry standard, which is now almost half a century old. This standard was published in 1973 by the American Nuclear Society (ANS) (1973, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants, La Grange Park, IL, ANS-N18.2-1973). It expresses the fundamental principle of nuclear safety and licensing, which is applied by vendors, licensees, and regulators alike. This Standard defines nuclear safety criteria and plant design requirements for plant operating situations or events according to their expected frequencies of occurrence. Those events that have high frequencies of occurrence must not pose a danger to the public. Events that could pose the greatest danger to the public must be limited, by design, to extremely low expected frequencies of occurrence. This concept is implemented by grouping postulated plant situations (or events) into categories that are defined according to their expected frequencies of occurrence. License","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91343186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The large amplitude vibrations of functionally graded (FG) beams consisting of metal rich layers at the bottom, ceramic rich layers at the top, and a concentrated mass at the mid-span have been studied using coupled displacement field method. Unlike traditional methods, the coupled displacement field method reduces the 2n undetermined coefficients problem, one each for total rotation and transverse displacement distribution of the beam at n modes, to n undetermined coefficients using a coupling equation obtained from the minimization of potential energy principle. A suitable admissible function having single undetermined coefficient has been assumed for total rotation distribution and the corresponding transverse displacement distribution of the beam has been obtained at each mode for hinged-hinged and clamped-clamped FG beams. The equations of motion for large amplitude vibrations of FG beams at each mode in terms of the undetermined coefficients are derived from the conservation of total energy principle. The free vibration problem is solved using harmonic balance method whereas the forced vibration problem is solved using the Newmark-β method to obtain the time response of the undetermined coefficients and the dynamic response of the beam has been computed from the modal superposition method. The proposed coupled displacement field approach has been successfully applied for the first time to study the large amplitude vibrations of FG beams with suitable validations, and the influence of power law index, slenderness ratio, harmonic load, and concentrated mass has been investigated.
{"title":"Large Amplitude Free and Forced Vibrations of Functionally Graded Timoshenko Beams Using Coupled Displacement Field Method","authors":"P. Sathujoda, Bharath Obalareddy, K. Meera Saheb","doi":"10.1115/1.4055080","DOIUrl":"https://doi.org/10.1115/1.4055080","url":null,"abstract":"\u0000 The large amplitude vibrations of functionally graded (FG) beams consisting of metal rich layers at the bottom, ceramic rich layers at the top, and a concentrated mass at the mid-span have been studied using coupled displacement field method. Unlike traditional methods, the coupled displacement field method reduces the 2n undetermined coefficients problem, one each for total rotation and transverse displacement distribution of the beam at n modes, to n undetermined coefficients using a coupling equation obtained from the minimization of potential energy principle. A suitable admissible function having single undetermined coefficient has been assumed for total rotation distribution and the corresponding transverse displacement distribution of the beam has been obtained at each mode for hinged-hinged and clamped-clamped FG beams. The equations of motion for large amplitude vibrations of FG beams at each mode in terms of the undetermined coefficients are derived from the conservation of total energy principle. The free vibration problem is solved using harmonic balance method whereas the forced vibration problem is solved using the Newmark-β method to obtain the time response of the undetermined coefficients and the dynamic response of the beam has been computed from the modal superposition method. The proposed coupled displacement field approach has been successfully applied for the first time to study the large amplitude vibrations of FG beams with suitable validations, and the influence of power law index, slenderness ratio, harmonic load, and concentrated mass has been investigated.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74209870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports a unified analogy-based computation methodology, together with a concept of multifield, multifunctional sensing, from elasticity to electromagnetic-chemical-thermal fields, via utilizing the similarities of mechanical-electromagnetic-chemical-thermal (MEMCT) field variables, governing equations, and the material properties pertaining to each individual field. Two equivalences are systemized, which are the field-formulation equivalence and surface-value equivalence. Due to similarity, a number of thermal, electromagnetic, or chemical solutions can be obtained from the direct degeneration of existing mechanical solutions by making specified equivalences of 2G↔k0↔ϖ0↔μ0↔β0 with G for shear modulus, k0 for heat conductivity, ϖ0 for dielectric permittivity, μ0 for magnetic permeability, and β0 for chemical diffusivity, as well as by setting Poisson’s ratio ν → 0.5. These specified equivalences enable quick solutions to other fields directly from mechanics formulations, such as those in the forms of the Galerkin vectors and Papkovich-Neuber potentials, and field coupling, by means of analogy. Several examples are given, one is used to demonstrate that the field solutions of a layered half-space with imperfect thermal, electromagnetic, or chemical interfaces can be readily obtained from the elastic solutions involving interfacial imperfections via the obtained formulation equivalence. A set of simple equations are derived to relate surface behaviors of different fields via the obtained surface-value equivalence, on which a concept of multifield sensing is proposed.
{"title":"A Unified Analogy-Based Computation Methodology From Elasticity to Electromagnetic-Chemical-Thermal Fields and a Concept of Multifield Sensing","authors":"Xin Zhang, Q. Wang","doi":"10.1115/1.4053910","DOIUrl":"https://doi.org/10.1115/1.4053910","url":null,"abstract":"\u0000 This paper reports a unified analogy-based computation methodology, together with a concept of multifield, multifunctional sensing, from elasticity to electromagnetic-chemical-thermal fields, via utilizing the similarities of mechanical-electromagnetic-chemical-thermal (MEMCT) field variables, governing equations, and the material properties pertaining to each individual field. Two equivalences are systemized, which are the field-formulation equivalence and surface-value equivalence. Due to similarity, a number of thermal, electromagnetic, or chemical solutions can be obtained from the direct degeneration of existing mechanical solutions by making specified equivalences of 2G↔k0↔ϖ0↔μ0↔β0 with G for shear modulus, k0 for heat conductivity, ϖ0 for dielectric permittivity, μ0 for magnetic permeability, and β0 for chemical diffusivity, as well as by setting Poisson’s ratio ν → 0.5. These specified equivalences enable quick solutions to other fields directly from mechanics formulations, such as those in the forms of the Galerkin vectors and Papkovich-Neuber potentials, and field coupling, by means of analogy. Several examples are given, one is used to demonstrate that the field solutions of a layered half-space with imperfect thermal, electromagnetic, or chemical interfaces can be readily obtained from the elastic solutions involving interfacial imperfections via the obtained formulation equivalence. A set of simple equations are derived to relate surface behaviors of different fields via the obtained surface-value equivalence, on which a concept of multifield sensing is proposed.","PeriodicalId":8652,"journal":{"name":"ASME Open Journal of Engineering","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79742498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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