Pub Date : 2020-08-29DOI: 10.1088/2633-1357/abad0d
Alessandro Cultrera, L. Callegaro
We propose a simple algorithm to locate the ‘corner’ of an L-curve, a function often used to select the regularisation parameter for the solution of ill-posed inverse problems. The algorithm involves the Menger curvature of a circumcircle and the golden section search method. It efficiently finds the regularisation parameter value corresponding to the maximum positive curvature region of the L-curve. The algorithm is applied to some commonly available test problems and compared to the typical way of locating the l-curve corner by means of its analytical curvature. The application of the algorithm to the data processing of an electrical resistance tomography experiment on thin conductive films is also reported.
{"title":"A simple algorithm to find the L-curve corner in the regularisation of ill-posed inverse problems","authors":"Alessandro Cultrera, L. Callegaro","doi":"10.1088/2633-1357/abad0d","DOIUrl":"https://doi.org/10.1088/2633-1357/abad0d","url":null,"abstract":"We propose a simple algorithm to locate the ‘corner’ of an L-curve, a function often used to select the regularisation parameter for the solution of ill-posed inverse problems. The algorithm involves the Menger curvature of a circumcircle and the golden section search method. It efficiently finds the regularisation parameter value corresponding to the maximum positive curvature region of the L-curve. The algorithm is applied to some commonly available test problems and compared to the typical way of locating the l-curve corner by means of its analytical curvature. The application of the algorithm to the data processing of an electrical resistance tomography experiment on thin conductive films is also reported.","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":"61192959","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 : 2020-08-28DOI: 10.1088/2633-1357/aba739
R. Kruse, Suboh Alkhushayni
The first confirmed case of COVID-19 in the United States was January 20, 2020 in Washington, while the first globally confirmed cases were in China in December 2019. The CDC's Influenza-like Illness Surveillance Network is used to track the amount of people who seek medical attention for influenza-like illnesses, along with the illness cause. The metric rILI- is used to assess the amount of people who test negative for influenza or any other specific cause. To assess the evidence of COVID-19 presence in the US in late December 2019 or early January 2020, rILI- data from 2010 to mid-March 2020 was used to perform three types of analysis. First, we forecast prediction intervals using data until mid-November 2019 and compared the predictions with observed values for the subsequent 16 weeks. Second, we performed residual hypothesis testing by removing the trend and seasonality in order to compare residuals from before and after November 17, 2019. Third, we used changepoint analysis to identify major changes in trend and seasonality. This study provides strong evidence of COVID-19 presence in the US in late December 2019 or early January 2020. Combined with the knowledge that COVID-19 was spreading across other parts of the world, anomalous patterns in ILINet data should have been a warning sign that COVID-19 was already spreading in the US. The purpose of the study was not to identify specific states, but South Dakota has the strongest evidence of any US state, followed by California, Delaware, Maine, and New Mexico.
{"title":"Identifying regional COVID-19 presence early with time series analysis","authors":"R. Kruse, Suboh Alkhushayni","doi":"10.1088/2633-1357/aba739","DOIUrl":"https://doi.org/10.1088/2633-1357/aba739","url":null,"abstract":"The first confirmed case of COVID-19 in the United States was January 20, 2020 in Washington, while the first globally confirmed cases were in China in December 2019. The CDC's Influenza-like Illness Surveillance Network is used to track the amount of people who seek medical attention for influenza-like illnesses, along with the illness cause. The metric rILI- is used to assess the amount of people who test negative for influenza or any other specific cause. To assess the evidence of COVID-19 presence in the US in late December 2019 or early January 2020, rILI- data from 2010 to mid-March 2020 was used to perform three types of analysis. First, we forecast prediction intervals using data until mid-November 2019 and compared the predictions with observed values for the subsequent 16 weeks. Second, we performed residual hypothesis testing by removing the trend and seasonality in order to compare residuals from before and after November 17, 2019. Third, we used changepoint analysis to identify major changes in trend and seasonality. This study provides strong evidence of COVID-19 presence in the US in late December 2019 or early January 2020. Combined with the knowledge that COVID-19 was spreading across other parts of the world, anomalous patterns in ILINet data should have been a warning sign that COVID-19 was already spreading in the US. The purpose of the study was not to identify specific states, but South Dakota has the strongest evidence of any US state, followed by California, Delaware, Maine, and New Mexico.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44958419","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 : 2020-08-27DOI: 10.1088/2633-1357/abb345
T. Zhao, C. Wu, M. Soleimani
Inspired by the human skin sensory mechanism, there are growing interests in creating a sense of touch in robotics. This work describes a new impedance based design to create an artificial tactile sensing skin. It has demonstrated that the electrical impedance tomography imaging technique allows for detecting the pressure distribution in a large area by a distributed touch sensor. The sensor is fabricated by filling a circular shaped phantom with liquid conductor and covering with an elastic shell on the top. The proposed sensor can detect the pressure applied to the elastic top using electrical impedance tomography imaging method. The sensor can therefore operate as a touch sensor mimicking a piezo-impedance operation in a simple fashion. The new sensor can differentiate between various force levels and their locations and thus produces a distribution of pressure. Such a simple sensor can function as a large area skin, enabling smarter human-machine interactions in emerging augmented reality and robotic applications.
{"title":"Ionic liquid based distributed touch sensor using electrical impedance tomography","authors":"T. Zhao, C. Wu, M. Soleimani","doi":"10.1088/2633-1357/abb345","DOIUrl":"https://doi.org/10.1088/2633-1357/abb345","url":null,"abstract":"Inspired by the human skin sensory mechanism, there are growing interests in creating a sense of touch in robotics. This work describes a new impedance based design to create an artificial tactile sensing skin. It has demonstrated that the electrical impedance tomography imaging technique allows for detecting the pressure distribution in a large area by a distributed touch sensor. The sensor is fabricated by filling a circular shaped phantom with liquid conductor and covering with an elastic shell on the top. The proposed sensor can detect the pressure applied to the elastic top using electrical impedance tomography imaging method. The sensor can therefore operate as a touch sensor mimicking a piezo-impedance operation in a simple fashion. The new sensor can differentiate between various force levels and their locations and thus produces a distribution of pressure. Such a simple sensor can function as a large area skin, enabling smarter human-machine interactions in emerging augmented reality and robotic applications.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46240551","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 : 2020-08-24DOI: 10.1088/2633-1357/abaa35
Jessica Alfonsi
Preliminary computational data are presented related to shape changes in the distribution of participation ratios of electronic wavefunctions from 1D and 2D Fibonacci quasicrystals. They suggest a likely connection between a distorsion-induced metal-insulator transition and the golden number spanning the word sequence underlying the quasiperiodicity of these systems.
{"title":"Searching for metal-insulator transition in Fibonacci quasicrystals by distribution analysis of electronic wavefunction participation ratios","authors":"Jessica Alfonsi","doi":"10.1088/2633-1357/abaa35","DOIUrl":"https://doi.org/10.1088/2633-1357/abaa35","url":null,"abstract":"Preliminary computational data are presented related to shape changes in the distribution of participation ratios of electronic wavefunctions from 1D and 2D Fibonacci quasicrystals. They suggest a likely connection between a distorsion-induced metal-insulator transition and the golden number spanning the word sequence underlying the quasiperiodicity of these systems.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46523521","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 : 2020-08-14DOI: 10.1088/2633-1357/abaa54
Robbi Vivek Vardhan, M. M, Saumen Mandal
In this contribution, an efficient aqueous solution combustion technique was implemented to achieve zirconia films on stainless steel substrates at 400 °C, by low capital and facile spray pyrolysis of a combustible precursor comprising stoichiometric amounts of zirconium oxynitrate hydrate and glycine. Detailed derivation of stoichiometric redox reaction is emphasized in the present work. Thermal behaviour of combustible precursor revealed the combustion temperature at ∼220 °C. Crystalline tetragonal zirconia film was deposited at 400 °C with a wavy morphological surface inferred from diffraction patterns and microstructural studies, respectively. Besides, an approach to fabricate spray pyrolysed YSZ films through combustion at 400 °C was successfully accomplished. These films can have a potential impact on biomedical and thermal barrier applications.
{"title":"Stoichiometric redox reaction-controlled, combustion assisted spray pyrolyzed zirconia films on stainless steel","authors":"Robbi Vivek Vardhan, M. M, Saumen Mandal","doi":"10.1088/2633-1357/abaa54","DOIUrl":"https://doi.org/10.1088/2633-1357/abaa54","url":null,"abstract":"In this contribution, an efficient aqueous solution combustion technique was implemented to achieve zirconia films on stainless steel substrates at 400 °C, by low capital and facile spray pyrolysis of a combustible precursor comprising stoichiometric amounts of zirconium oxynitrate hydrate and glycine. Detailed derivation of stoichiometric redox reaction is emphasized in the present work. Thermal behaviour of combustible precursor revealed the combustion temperature at ∼220 °C. Crystalline tetragonal zirconia film was deposited at 400 °C with a wavy morphological surface inferred from diffraction patterns and microstructural studies, respectively. Besides, an approach to fabricate spray pyrolysed YSZ films through combustion at 400 °C was successfully accomplished. These films can have a potential impact on biomedical and thermal barrier applications.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46256367","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 : 2020-08-14DOI: 10.1088/2633-1357/aba7f6
M. Craven, Yaoling Wang, Haiping Yang, Chunfei Wu, X. Tu
An innovative integrated gasification and plasma-catalytic system has been developed to produce cleaner syngas from a model biofeedstock (α-cellulose). The influence of Co/γ-Al2O3 catalyst on the plasma reforming of tar-contaminated syngas has been investigated using a cylindrical dielectric barrier discharge reactor. The results show that plasma-catalytic processing of the syngas from biomass gasification significantly reduces the concentration of tars by 88% and enhances the total gas product yield and the syngas ratio (H2/CO) by up to 90%.
{"title":"Integrated gasification and non-thermal plasma-catalysis system for cleaner syngas production from cellulose","authors":"M. Craven, Yaoling Wang, Haiping Yang, Chunfei Wu, X. Tu","doi":"10.1088/2633-1357/aba7f6","DOIUrl":"https://doi.org/10.1088/2633-1357/aba7f6","url":null,"abstract":"An innovative integrated gasification and plasma-catalytic system has been developed to produce cleaner syngas from a model biofeedstock (α-cellulose). The influence of Co/γ-Al2O3 catalyst on the plasma reforming of tar-contaminated syngas has been investigated using a cylindrical dielectric barrier discharge reactor. The results show that plasma-catalytic processing of the syngas from biomass gasification significantly reduces the concentration of tars by 88% and enhances the total gas product yield and the syngas ratio (H2/CO) by up to 90%.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45315187","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 : 2020-08-14DOI: 10.1088/2633-1357/aba5a2
C. Duston
We present an algorithm which determines the fundamental group of a spatial section using topspin networks. Tracking the topology of the spatial section is a unique feature of this approach, which is not possible in standard Loop Quantum Gravity. This leads to an example of spatial topology change in a smooth 4-manifold represented by a topspin foam.
{"title":"An illustration of topology change in quantum gravity using the topspin network formalism","authors":"C. Duston","doi":"10.1088/2633-1357/aba5a2","DOIUrl":"https://doi.org/10.1088/2633-1357/aba5a2","url":null,"abstract":"We present an algorithm which determines the fundamental group of a spatial section using topspin networks. Tracking the topology of the spatial section is a unique feature of this approach, which is not possible in standard Loop Quantum Gravity. This leads to an example of spatial topology change in a smooth 4-manifold represented by a topspin foam.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41550287","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 : 2020-08-14DOI: 10.1088/2633-1357/aba1f6
S. Krivov, A. Lazukin, Y. A. Serdyukov, S. Gundareva, G. Romanov
In this work an effect of the 10-min pre-sowing treatment by the constant electric field with the 3 kV cm−1 electric field strength on the soft spring wheat seed germination is studied at various positions of the seeds in a plane-parallel electrode system. The effects of the electric field direction and contact conditions of the seeds with a plane aluminum electrode (no contact, when the seeds lie on the isolating plate; contact with the positive or negative high-voltage or grounded electrode) are compared. The treatment response is estimated by the morphological characteristics of 3-day seedlings—germination, the shoot length and the length of individual roots. At all modes, the treatment does not change seed germination. At each considered variant of seed location, the electric field effect did not reduce the average length of the root system and the shoot length below the ones at the control variant. The significant increase of morphological characteristics is achieved at the seed contact with the high voltage electrode.
{"title":"Effect of constant high-voltage electric field on wheat seed germination","authors":"S. Krivov, A. Lazukin, Y. A. Serdyukov, S. Gundareva, G. Romanov","doi":"10.1088/2633-1357/aba1f6","DOIUrl":"https://doi.org/10.1088/2633-1357/aba1f6","url":null,"abstract":"In this work an effect of the 10-min pre-sowing treatment by the constant electric field with the 3 kV cm−1 electric field strength on the soft spring wheat seed germination is studied at various positions of the seeds in a plane-parallel electrode system. The effects of the electric field direction and contact conditions of the seeds with a plane aluminum electrode (no contact, when the seeds lie on the isolating plate; contact with the positive or negative high-voltage or grounded electrode) are compared. The treatment response is estimated by the morphological characteristics of 3-day seedlings—germination, the shoot length and the length of individual roots. At all modes, the treatment does not change seed germination. At each considered variant of seed location, the electric field effect did not reduce the average length of the root system and the shoot length below the ones at the control variant. The significant increase of morphological characteristics is achieved at the seed contact with the high voltage electrode.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43426970","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 : 2020-07-21DOI: 10.1088/2633-1357/aba1f7
SheikhRashel Al Ahmed, J. Ferdous, Md. Suruz Mian
A novel heterojunction structure of cadmium telluride (CdTe)/zinc sulfide (ZnS)/zinc telluride (ZnTe) for thin-film solar cell (TFSC) applications was investigated numerically by Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D). We made a comparative study on the performance of single-layer of Si/CdTe and multi-layers of Si/CdTe/ZnS/ZnTe structures. The optimum values for the thicknesses of CdTe absorber, ZnS, and ZnTe layers in the cell were found to be 2500, 40, and 80 nm, respectively. In the present work, the conversion efficiency (η) of 21.38% was obtained with open-circuit voltage, Voc = 1.01 V, short-circuit current density, Jsc = 29.32 mA cm−2, and fill-factor, FF = 72.06% in case of multi-layer structure with antireflection coatings (ARCs). The simulation results suggest that the ARC layers presented in this study would be effective to fabricate the high-efficiency solar cells.
{"title":"Development of a novel CdTe/ZnS/ZnTe heterojunction thin-film solar cells: a numerical approach","authors":"SheikhRashel Al Ahmed, J. Ferdous, Md. Suruz Mian","doi":"10.1088/2633-1357/aba1f7","DOIUrl":"https://doi.org/10.1088/2633-1357/aba1f7","url":null,"abstract":"A novel heterojunction structure of cadmium telluride (CdTe)/zinc sulfide (ZnS)/zinc telluride (ZnTe) for thin-film solar cell (TFSC) applications was investigated numerically by Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D). We made a comparative study on the performance of single-layer of Si/CdTe and multi-layers of Si/CdTe/ZnS/ZnTe structures. The optimum values for the thicknesses of CdTe absorber, ZnS, and ZnTe layers in the cell were found to be 2500, 40, and 80 nm, respectively. In the present work, the conversion efficiency (η) of 21.38% was obtained with open-circuit voltage, Voc = 1.01 V, short-circuit current density, Jsc = 29.32 mA cm−2, and fill-factor, FF = 72.06% in case of multi-layer structure with antireflection coatings (ARCs). The simulation results suggest that the ARC layers presented in this study would be effective to fabricate the high-efficiency solar cells.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2633-1357/aba1f7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48798208","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 : 2020-07-21DOI: 10.1088/2633-1357/ab92f6
C. Ottaviani, G. Spedalieri, S. Braunstein, S. Pirandola
A general security proof of continuous variable (CV) measurement device independent (MDI) quantum key distribution (QKD) should not be automatically reduced to the analysis of one-mode Gaussian attacks (in particular, independent entangling-cloner attacks). To stress this point, the present work provides a very simple (almost trivial) argument, showing that there are an infinite number of two-mode Gaussian attacks that cannot be reduced to or simulated by one-mode Gaussian attacks. This result further confirms that the security analysis of CV-MDI-QKD must generally involve a careful minimization over two-mode attacks as originally performed in (Pirandola et al, 2015 Nature Photon. 9, 397–402; arXiv:1312.4104 (2013)).
{"title":"CV-MDI-QKD with coherent state: beyond one-mode Gaussian attacks","authors":"C. Ottaviani, G. Spedalieri, S. Braunstein, S. Pirandola","doi":"10.1088/2633-1357/ab92f6","DOIUrl":"https://doi.org/10.1088/2633-1357/ab92f6","url":null,"abstract":"A general security proof of continuous variable (CV) measurement device independent (MDI) quantum key distribution (QKD) should not be automatically reduced to the analysis of one-mode Gaussian attacks (in particular, independent entangling-cloner attacks). To stress this point, the present work provides a very simple (almost trivial) argument, showing that there are an infinite number of two-mode Gaussian attacks that cannot be reduced to or simulated by one-mode Gaussian attacks. This result further confirms that the security analysis of CV-MDI-QKD must generally involve a careful minimization over two-mode attacks as originally performed in (Pirandola et al, 2015 Nature Photon. 9, 397–402; arXiv:1312.4104 (2013)).","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45178828","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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