Pub Date : 2020-09-01DOI: 10.1088/2633-1357/abb9f1
E. Grubert
This note uses electricity generator level 2001–2018 US capacity, generation, and heat input data to evaluate trends in same-plant capacity factor (how much plants run) and heat rate (how efficiently plants run) as plants age. Based on compound annual growth rates for capacity factor and, for thermal plants, heat rate, and based on the subset of US plants that have been operating since 2010 or earlier, same-plant capacity factors increased slightly, and heat rates decreased slightly, between 2001–2018 (weighted average based on 2018 plant capacity). Trends vary by region, fuel, and plant age. Notably, US natural gas-fired power plants tended to run more, and more efficiently, as they aged, while coal-fired power plants tended to run less, and less efficiently. Potential drivers include relative plant age, policy, financial competitiveness, and an anticipated tendency for plant operators to react to the effects of equipment aging with maintenance, repair, replacement, and optimization. These observations can inform committed emissions-based research, which requires making assumptions about how plant operational characteristics change (or do not) as they age.
{"title":"Same-plant trends in capacity factor and heat rate for US power plants, 2001–2018","authors":"E. Grubert","doi":"10.1088/2633-1357/abb9f1","DOIUrl":"https://doi.org/10.1088/2633-1357/abb9f1","url":null,"abstract":"This note uses electricity generator level 2001–2018 US capacity, generation, and heat input data to evaluate trends in same-plant capacity factor (how much plants run) and heat rate (how efficiently plants run) as plants age. Based on compound annual growth rates for capacity factor and, for thermal plants, heat rate, and based on the subset of US plants that have been operating since 2010 or earlier, same-plant capacity factors increased slightly, and heat rates decreased slightly, between 2001–2018 (weighted average based on 2018 plant capacity). Trends vary by region, fuel, and plant age. Notably, US natural gas-fired power plants tended to run more, and more efficiently, as they aged, while coal-fired power plants tended to run less, and less efficiently. Potential drivers include relative plant age, policy, financial competitiveness, and an anticipated tendency for plant operators to react to the effects of equipment aging with maintenance, repair, replacement, and optimization. These observations can inform committed emissions-based research, which requires making assumptions about how plant operational characteristics change (or do not) as they age.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47126813","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}
Pub Date : 2020-09-01DOI: 10.1088/2633-1357/abb2af
Chiranjib Mukhopadhyay, A. Pati, S. Sazim
We prove a generalized version of a previously conjectured inequality by Zhang et al (Zhang et al 2018 Phys. Lett. A 382, 1516–23) for the quantum addition operation defined by Datta et al (Audenaert et al 2016 J. Math. Phy. 57, 052202) in the context of proving an entropy power inequality for qubits. We also show that the quantum addition operation commutes with an incoherent channel, which may have possible implications for resource theories of coherence in optical settings.
我们证明了Zhang等人先前猜想的不等式的广义版本(Zhang et al 2018 Phys)。列托人。由Datta等人定义的量子加法运算(Audenaert et al 2016 J. Math)， A 382, 1516-23。Phy. 57, 052202)在证明量子比特的熵幂不等式的背景下。我们还表明，量子加法操作与非相干信道进行交换，这可能对光学环境中的相干资源理论产生影响。
{"title":"Quantum addition imparts less disorder than mixing and commutes with incoherent channels","authors":"Chiranjib Mukhopadhyay, A. Pati, S. Sazim","doi":"10.1088/2633-1357/abb2af","DOIUrl":"https://doi.org/10.1088/2633-1357/abb2af","url":null,"abstract":"We prove a generalized version of a previously conjectured inequality by Zhang et al (Zhang et al 2018 Phys. Lett. A 382, 1516–23) for the quantum addition operation defined by Datta et al (Audenaert et al 2016 J. Math. Phy. 57, 052202) in the context of proving an entropy power inequality for qubits. We also show that the quantum addition operation commutes with an incoherent channel, which may have possible implications for resource theories of coherence in optical settings.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61193648","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abaf37
S. Rudz, Robin Flaugere, M. Wartel, S. Pellerin, J. Hanus
In laser-induced breakdown experiments, the absorbed energy is one of the first measured parameters. For a given optical configuration and incident energy, the measured absorbed energy depending on pressure always exhibits a similar curve for the tested gases: argon, nitrogen, carbon dioxide and air. This work presents an empirical modelling to predict the pressure dependence of the absorbed energy in mono-atomic and molecular gas efficiently. The first series of experiments, involving Ar, N2 and CO2, presents its efficiency over pressure from 50 to 2400 mbar and incident laser energies from ∼15 to ∼135 mJ. The second series presents the effectiveness of this modelling on air. All experiments are conducted with a Nd:YAG laser at 532 nm and a focal radius of 4.23 μm.
{"title":"Normalization of absorbed energy and pressure in laser-induced breakdown in mono-atomic and molecular gases according to incident laser energy and initial pressure","authors":"S. Rudz, Robin Flaugere, M. Wartel, S. Pellerin, J. Hanus","doi":"10.1088/2633-1357/abaf37","DOIUrl":"https://doi.org/10.1088/2633-1357/abaf37","url":null,"abstract":"In laser-induced breakdown experiments, the absorbed energy is one of the first measured parameters. For a given optical configuration and incident energy, the measured absorbed energy depending on pressure always exhibits a similar curve for the tested gases: argon, nitrogen, carbon dioxide and air. This work presents an empirical modelling to predict the pressure dependence of the absorbed energy in mono-atomic and molecular gas efficiently. The first series of experiments, involving Ar, N2 and CO2, presents its efficiency over pressure from 50 to 2400 mbar and incident laser energies from ∼15 to ∼135 mJ. The second series presents the effectiveness of this modelling on air. All experiments are conducted with a Nd:YAG laser at 532 nm and a focal radius of 4.23 μm.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42570101","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/ababe9
Abhinav, R. Ribeiro, R. Raghav
The transition in temperature and associated stress induced during machining, may affect the structural integrity of the Al7075-T6 alloy. In the present study, Steinberg Guinan material parameters were used to investigate the dynamic behaviour viz chip morphology (fracture mechanism), temperature change and flow stress in the elasto-visco material Al7075-T6. An explicit algorithm, was adopted to investigate the outcomes. Results showed chip formation and the mode of fracture was closely related with depth of cut and can influence the temperature and flow stress during the machining process. Work hardening and edge dislocation slip in the secondary shear zone was observed to have a notable influence. An optimal machining condition was found between 0.6 and 0.7 mm depth of cut.
{"title":"Elasto-Visco behavior of Al7075-T6 using a numerical technique","authors":"Abhinav, R. Ribeiro, R. Raghav","doi":"10.1088/2633-1357/ababe9","DOIUrl":"https://doi.org/10.1088/2633-1357/ababe9","url":null,"abstract":"The transition in temperature and associated stress induced during machining, may affect the structural integrity of the Al7075-T6 alloy. In the present study, Steinberg Guinan material parameters were used to investigate the dynamic behaviour viz chip morphology (fracture mechanism), temperature change and flow stress in the elasto-visco material Al7075-T6. An explicit algorithm, was adopted to investigate the outcomes. Results showed chip formation and the mode of fracture was closely related with depth of cut and can influence the temperature and flow stress during the machining process. Work hardening and edge dislocation slip in the secondary shear zone was observed to have a notable influence. An optimal machining condition was found between 0.6 and 0.7 mm depth of cut.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47521839","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abae79
Ruochen Sun, Zhichao Feng, Song Gao, Pingan Liu, H. Qi, N. Song
In this study, three lead (Pb) nanoparticles, including cone, sphere and cylinder, are modeled and melted using molecular dynamic (MD) simulations. The choice of initial geometries mainly affects the initial and middle stages of phase transition. Initially, the melting point of the cone model is much lower than other two models. This is because the transition of the cone model is induced by its sharp edge, which is prone to be melted. Then, the transition of all models keeps toward the centre of mass. Meanwhile, cone and cylinder models are deformed into spheres. The deforming rate is higher than transition. Finally, all three models were fully melted into the shape of the spheres. Therefore, initial Pb nano-geometries do not affect the final stage of the phase transition.
{"title":"Using molecular dynamic simulations to describe the solid-liquid phase transition of lead nanoparticles with different nano-geometries","authors":"Ruochen Sun, Zhichao Feng, Song Gao, Pingan Liu, H. Qi, N. Song","doi":"10.1088/2633-1357/abae79","DOIUrl":"https://doi.org/10.1088/2633-1357/abae79","url":null,"abstract":"In this study, three lead (Pb) nanoparticles, including cone, sphere and cylinder, are modeled and melted using molecular dynamic (MD) simulations. The choice of initial geometries mainly affects the initial and middle stages of phase transition. Initially, the melting point of the cone model is much lower than other two models. This is because the transition of the cone model is induced by its sharp edge, which is prone to be melted. Then, the transition of all models keeps toward the centre of mass. Meanwhile, cone and cylinder models are deformed into spheres. The deforming rate is higher than transition. Finally, all three models were fully melted into the shape of the spheres. Therefore, initial Pb nano-geometries do not affect the final stage of the phase transition.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45673701","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abb0f5
Yashpal Gupta, Varghese Paul V, A. Jacob, A. Mohanty
In this study, the effect of the core thickness of the sandwich composite on its flexural strength was investigated. E-glass fibre reinforced epoxy-based laminates were used as the skin materials whereas a polyurethane foam was used as the core material with varying thickness of 5, 7, and 9 mm. The experimental/theoretical and FEA analysis were carried out. Results indicated that as core thickness increased, the axial face stresses/core shear stresses and total deformation decreased. This improved the composite structural properties. This improvement was accompanied by a minor increase in weight. A good concurrence was observed between theoretical and FEA results. These results allow us to compare and select optimum parameters for aerospace applications.
{"title":"Effect of the core thickness on the flexural behaviour of polymer foam sandwich structures","authors":"Yashpal Gupta, Varghese Paul V, A. Jacob, A. Mohanty","doi":"10.1088/2633-1357/abb0f5","DOIUrl":"https://doi.org/10.1088/2633-1357/abb0f5","url":null,"abstract":"In this study, the effect of the core thickness of the sandwich composite on its flexural strength was investigated. E-glass fibre reinforced epoxy-based laminates were used as the skin materials whereas a polyurethane foam was used as the core material with varying thickness of 5, 7, and 9 mm. The experimental/theoretical and FEA analysis were carried out. Results indicated that as core thickness increased, the axial face stresses/core shear stresses and total deformation decreased. This improved the composite structural properties. This improvement was accompanied by a minor increase in weight. A good concurrence was observed between theoretical and FEA results. These results allow us to compare and select optimum parameters for aerospace applications.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46101769","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abaf36
Sushobhan Pradhan, S. Mohanta
This article presents a detail experimental procedure to perform float-and-sink tests for classifying coal samples according to their densities. Moreover, this article emphasizes obtaining ‘partition curves’ for three different coal samples (heavy media bath, big barrel and small barrel), which helps in evaluating and demonstrating classifier performance. Calculations of independent variables such as ‘Probable Error’ and ‘Imperfection’ are also discussed for partition curve that helps in evaluating the effectiveness of various beneficiation equipment used for the upgradation of quality of coal received from different coal mines. It was observed that there is a tendency for the partition curves to steepen as the density of separation decreases. In other words, separations at lower density is sharper than separations at higher density.
{"title":"A method to perform float-and-sink test for separation of coal samples of various densities and determination of ‘Probable Error’ and ‘Imperfection’","authors":"Sushobhan Pradhan, S. Mohanta","doi":"10.1088/2633-1357/abaf36","DOIUrl":"https://doi.org/10.1088/2633-1357/abaf36","url":null,"abstract":"This article presents a detail experimental procedure to perform float-and-sink tests for classifying coal samples according to their densities. Moreover, this article emphasizes obtaining ‘partition curves’ for three different coal samples (heavy media bath, big barrel and small barrel), which helps in evaluating and demonstrating classifier performance. Calculations of independent variables such as ‘Probable Error’ and ‘Imperfection’ are also discussed for partition curve that helps in evaluating the effectiveness of various beneficiation equipment used for the upgradation of quality of coal received from different coal mines. It was observed that there is a tendency for the partition curves to steepen as the density of separation decreases. In other words, separations at lower density is sharper than separations at higher density.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42854407","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/ab99cc
Lewa’ Alzaleq, V. Manoranjan
In this short note, we study the Fisher-KPP population model with a time-dependent Allee threshold. We consider the time dependence as sinusoidal functions and rational functions as they relate to varying environmental situations of the model. Employing the generalized Riccati equation mapping method, we obtain exact traveling wave solutions. Also, when the time-dependent Allee threshold decays to a constant value, we recover the traveling wave solution of the degenerate Fitzhugh-Nagumo equation from our general solution.
{"title":"Analysis of the Fisher-KPP equation with a time-dependent Allee effect","authors":"Lewa’ Alzaleq, V. Manoranjan","doi":"10.1088/2633-1357/ab99cc","DOIUrl":"https://doi.org/10.1088/2633-1357/ab99cc","url":null,"abstract":"In this short note, we study the Fisher-KPP population model with a time-dependent Allee threshold. We consider the time dependence as sinusoidal functions and rational functions as they relate to varying environmental situations of the model. Employing the generalized Riccati equation mapping method, we obtain exact traveling wave solutions. Also, when the time-dependent Allee threshold decays to a constant value, we recover the traveling wave solution of the degenerate Fitzhugh-Nagumo equation from our general solution.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2633-1357/ab99cc","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43101186","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abaf67
M. Yadav, V. Yadav
In the present study, authors are conceptually showing that the classically considered time limit to use the semi-infinite approximate solutions is highly conservative, particularly at the internal location(s) inside the finite heat conduction medium. Accordingly, a new length scale, which accounts the heat propagation from the far-field boundary condition as well, is proposed to ascertain the prolonged time limit. The proposed time limit is obtained by comparing the temperature distribution in a finite heat conduction problem with its equivalent semi-infinite model. Overall, three standard one-dimensional heat conduction problems are analysed and the proposed time limit is found to be valid in all three problems. The new time limit will certainly boost the utility of the semi-infinite solutions and rejuvenate the interest of the scientific community in such solutions.
{"title":"Time limit for using the semi-infinite heat transfer solutions: a novel approach","authors":"M. Yadav, V. Yadav","doi":"10.1088/2633-1357/abaf67","DOIUrl":"https://doi.org/10.1088/2633-1357/abaf67","url":null,"abstract":"In the present study, authors are conceptually showing that the classically considered time limit to use the semi-infinite approximate solutions is highly conservative, particularly at the internal location(s) inside the finite heat conduction medium. Accordingly, a new length scale, which accounts the heat propagation from the far-field boundary condition as well, is proposed to ascertain the prolonged time limit. The proposed time limit is obtained by comparing the temperature distribution in a finite heat conduction problem with its equivalent semi-infinite model. Overall, three standard one-dimensional heat conduction problems are analysed and the proposed time limit is found to be valid in all three problems. The new time limit will certainly boost the utility of the semi-infinite solutions and rejuvenate the interest of the scientific community in such solutions.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41393529","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}
Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abafed
Hollis Williams
We study the problem of a thin liquid film falling down an inclined slope. We use a simplified model to study the evolution and morphology of the solitary waves on a thin film with a periodic forcing at the inlet. In recent work by Denner et al (2016 Phys. Rev. E 93, 033121), the regime for high Re was studied and results obtained on the geometry and dispersion of the waves. We wish to establish whether similar results are observed in a regime of smaller Re and examine quantities which can be compared with experiment, such as the maximum and minimum film height as a function of a rescaled Reynolds number which accounts for the inclination of the substrate. Our results show some evidence that h min collapses onto a single curve when plotted as a function of Re*, and approaches the absolute value of h min/h N = 0.375 in agreement with results obtained at higher Re. We also obtain a curve for d/λ which can be compared with the results reported in (Denner et al 2016 Phys. Rev. E 93, 033121).
{"title":"Solitary waves on falling liquid films in the low Reynolds number regime","authors":"Hollis Williams","doi":"10.1088/2633-1357/abafed","DOIUrl":"https://doi.org/10.1088/2633-1357/abafed","url":null,"abstract":"We study the problem of a thin liquid film falling down an inclined slope. We use a simplified model to study the evolution and morphology of the solitary waves on a thin film with a periodic forcing at the inlet. In recent work by Denner et al (2016 Phys. Rev. E 93, 033121), the regime for high Re was studied and results obtained on the geometry and dispersion of the waves. We wish to establish whether similar results are observed in a regime of smaller Re and examine quantities which can be compared with experiment, such as the maximum and minimum film height as a function of a rescaled Reynolds number which accounts for the inclination of the substrate. Our results show some evidence that h min collapses onto a single curve when plotted as a function of Re*, and approaches the absolute value of h min/h N = 0.375 in agreement with results obtained at higher Re. We also obtain a curve for d/λ which can be compared with the results reported in (Denner et al 2016 Phys. Rev. E 93, 033121).","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47022202","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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