Pub Date : 2020-10-13DOI: 10.1088/2633-1357/abc968
Narayana Moorthy N, T. Kanish
Friction drilling is considered a non-traditional hole making method in which the workpiece is penetrated by a conical rotating instrument and a bush is formed without producing chips in a single cycle. In the present work, using a CNC milling machine, the friction drilling process was carried out on Be-Cu C17200 plate material. The process parameters such as spindle speed and feed rate were performed over three levels of workpiece material thickness. Surface roughness, bush length, and the thrust force of the drilled holes were analysed following drilling. For optimal surface roughness and bush formation, it is noted that spindle speed and feed rate play a significant role in friction drilling. Higher feed rate and thrust force have a direct effect on greater roughness of the surface and increased bush length. Better bushing and surface roughness are given by an increase in spindle speed.
{"title":"The impact of process parameters on surface roughness and bushing in friction drilling","authors":"Narayana Moorthy N, T. Kanish","doi":"10.1088/2633-1357/abc968","DOIUrl":"https://doi.org/10.1088/2633-1357/abc968","url":null,"abstract":"Friction drilling is considered a non-traditional hole making method in which the workpiece is penetrated by a conical rotating instrument and a bush is formed without producing chips in a single cycle. In the present work, using a CNC milling machine, the friction drilling process was carried out on Be-Cu C17200 plate material. The process parameters such as spindle speed and feed rate were performed over three levels of workpiece material thickness. Surface roughness, bush length, and the thrust force of the drilled holes were analysed following drilling. For optimal surface roughness and bush formation, it is noted that spindle speed and feed rate play a significant role in friction drilling. Higher feed rate and thrust force have a direct effect on greater roughness of the surface and increased bush length. Better bushing and surface roughness are given by an increase in spindle speed.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46367512","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 : 2020-10-10DOI: 10.1088/2633-1357/abd1e3
Movaffaq Kateb
The stencil growth of nanoscale patterns using molecular dynamics simulation has been demonstrated. A comparison has been made to a film grown by identical conditions without the stencil. It is shown that in the case of nanoscale proximity between mask and substrate, patterns of the same dimension as the mask can be obtained. The results also indicate that the obtained nanorod presents a higher surface area than the corresponding thin film. It is demonstrated that nanorod surface roughness decreases by merging adjacent surface irregularity during the deposition.
{"title":"Stencil growth of metallic nanorod: An atomistic simulation","authors":"Movaffaq Kateb","doi":"10.1088/2633-1357/abd1e3","DOIUrl":"https://doi.org/10.1088/2633-1357/abd1e3","url":null,"abstract":"The stencil growth of nanoscale patterns using molecular dynamics simulation has been demonstrated. A comparison has been made to a film grown by identical conditions without the stencil. It is shown that in the case of nanoscale proximity between mask and substrate, patterns of the same dimension as the mask can be obtained. The results also indicate that the obtained nanorod presents a higher surface area than the corresponding thin film. It is demonstrated that nanorod surface roughness decreases by merging adjacent surface irregularity during the deposition.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43606979","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 : 2020-10-10DOI: 10.1088/2633-1357/abbd2b
N. J. Dala, Wu Zhong-wen, Ding Xiao-bin, Xie Lu-you, Dong Chen-zhong
The spectra originating from the electric dipole transitions of nd (n = 3 − 5) core excited states to the 5f valence states of Am2+ to Am8+ ions have been calculated using the Dirac-Hartee-Fock method, which are compared with the results from the Flexible Atomic Code for the explanation of accuracy. It is found that both the M4,5(3d→5f) and N4,5(4d→5f) spectra of these ions consist of two peaks that are well separated in energy respectively by 202.11 eV and 49.10 eV due to strong spin-orbit interaction of the 3d−1 and 4d−1 hole state, while the O4,5(5d→5f) spectra show a broad quasi-continuum profile.
{"title":"The effect of 5f states on the nd → 5f transition energies and spectra of americium ions","authors":"N. J. Dala, Wu Zhong-wen, Ding Xiao-bin, Xie Lu-you, Dong Chen-zhong","doi":"10.1088/2633-1357/abbd2b","DOIUrl":"https://doi.org/10.1088/2633-1357/abbd2b","url":null,"abstract":"The spectra originating from the electric dipole transitions of nd (n = 3 − 5) core excited states to the 5f valence states of Am2+ to Am8+ ions have been calculated using the Dirac-Hartee-Fock method, which are compared with the results from the Flexible Atomic Code for the explanation of accuracy. It is found that both the M4,5(3d→5f) and N4,5(4d→5f) spectra of these ions consist of two peaks that are well separated in energy respectively by 202.11 eV and 49.10 eV due to strong spin-orbit interaction of the 3d−1 and 4d−1 hole state, while the O4,5(5d→5f) spectra show a broad quasi-continuum profile.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43657872","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 : 2020-10-08DOI: 10.1088/2633-1357/abbb15
S. Mehtab, M. Zaidi, Pragati S. Joshi, D. Bawari
A microwave (MW) assisted process was evolved to synthesize a series of polymer nanocomposites (PNCs) through 2,2-azobisisobutyronitrile (AIBN) initiated free radical in situ polymerization of acrylonitrile (AN) in presence of nanobariumtitanate (NBT). The reaction conditions were optimized and microwave power ranging 25 to 100 W over 10 min was found to be most suited for the synthesis of PNCs. Synthesis of PNCs has been ascertained through UV–vis, FTIR spectroscopy and microstructure were investigated through XRD and AFM. TG-DTA-DTG proclaims that PNCs acquire lower moisture content and higher heat resistance as compared to polyacrylonitrile (PAN). The synthesized PNCs have been applied as sensing material to develop electrochemical probe for detection of doxorubicin (DOX). The presence of DOX (0.01%, w/v) in phosphate buffer at pH 7.4 has shown a remarkable increase in the peak current at PNCs modified glassy carbon electrode (GCE). Cyclic voltammetric (CV) studies proof good acceptance of nanocomposites as sensing material for anti cancerous drug DOX.
{"title":"Synthesis and characterization of barium titanate/polyacrylonitrile nanocomposite for electrochemical sensing of doxorubicin","authors":"S. Mehtab, M. Zaidi, Pragati S. Joshi, D. Bawari","doi":"10.1088/2633-1357/abbb15","DOIUrl":"https://doi.org/10.1088/2633-1357/abbb15","url":null,"abstract":"A microwave (MW) assisted process was evolved to synthesize a series of polymer nanocomposites (PNCs) through 2,2-azobisisobutyronitrile (AIBN) initiated free radical in situ polymerization of acrylonitrile (AN) in presence of nanobariumtitanate (NBT). The reaction conditions were optimized and microwave power ranging 25 to 100 W over 10 min was found to be most suited for the synthesis of PNCs. Synthesis of PNCs has been ascertained through UV–vis, FTIR spectroscopy and microstructure were investigated through XRD and AFM. TG-DTA-DTG proclaims that PNCs acquire lower moisture content and higher heat resistance as compared to polyacrylonitrile (PAN). The synthesized PNCs have been applied as sensing material to develop electrochemical probe for detection of doxorubicin (DOX). The presence of DOX (0.01%, w/v) in phosphate buffer at pH 7.4 has shown a remarkable increase in the peak current at PNCs modified glassy carbon electrode (GCE). Cyclic voltammetric (CV) studies proof good acceptance of nanocomposites as sensing material for anti cancerous drug DOX.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43999279","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 : 2020-10-01DOI: 10.1088/2633-1357/abb9f2
V. Kher, Ravibabu Mulaveesala, Anju Rani, V. Arora
Thermal Non-Destructive Testing and Evaluation (TNDT&E) plays a crucial role in industrial quality control and structural health monitoring of a variety of materials. Among various TNDT&E modalities, active Infrared Thermography (IRT) has emerged as an extremely promising approach and has gained enormous significance due to its quick, whole field, non-contact and quantitative defect detection capabilities. Pulse Compression favourable Thermal Wave Imaging (PCTWI) especially Frequency Modulated Thermal Wave Imaging (FMTWI) has become popular among a number of active IRT techniques because of increment in defect detection sensitivity as well as test resolution. The present work attempts to explore the applicability of differential filtering post processing scheme for pulse compression favourable FMTWI for enhanced detection contrast, resolution and Probability of Detection (PoD). The proposed scheme has been applied on a Glass Fibre Reinforced Polymer (GFRP) sample with sub-surface flat bottom hole (FBH) defects located inside the sample at different depths. The results presented clearly demonstrate that the differential contrast approach enhances the defect detection probabilities by considering maximum and minimum deviation dip values as a figure of merit. Hence, pulse compression favourable FMTWI employing differential filtering manifests higher Probability of Detection (PoD) for defects located at different depths as compared to taking into account the peak Correlation Coefficient (CC) as a statistical figure of merit. Further Probability of Detection (PoD) of the pulse compression favourable FMTWI technique has been improved by differential filtering post-processing based scheme that reduces the memory requirement, computational cost as well as complexity.
{"title":"Investigations on probability of defect detection using differential filtering for pulse compression favourable frequency modulated thermal wave imaging for inspection of glass fibre reinforced polymers","authors":"V. Kher, Ravibabu Mulaveesala, Anju Rani, V. Arora","doi":"10.1088/2633-1357/abb9f2","DOIUrl":"https://doi.org/10.1088/2633-1357/abb9f2","url":null,"abstract":"Thermal Non-Destructive Testing and Evaluation (TNDT&E) plays a crucial role in industrial quality control and structural health monitoring of a variety of materials. Among various TNDT&E modalities, active Infrared Thermography (IRT) has emerged as an extremely promising approach and has gained enormous significance due to its quick, whole field, non-contact and quantitative defect detection capabilities. Pulse Compression favourable Thermal Wave Imaging (PCTWI) especially Frequency Modulated Thermal Wave Imaging (FMTWI) has become popular among a number of active IRT techniques because of increment in defect detection sensitivity as well as test resolution. The present work attempts to explore the applicability of differential filtering post processing scheme for pulse compression favourable FMTWI for enhanced detection contrast, resolution and Probability of Detection (PoD). The proposed scheme has been applied on a Glass Fibre Reinforced Polymer (GFRP) sample with sub-surface flat bottom hole (FBH) defects located inside the sample at different depths. The results presented clearly demonstrate that the differential contrast approach enhances the defect detection probabilities by considering maximum and minimum deviation dip values as a figure of merit. Hence, pulse compression favourable FMTWI employing differential filtering manifests higher Probability of Detection (PoD) for defects located at different depths as compared to taking into account the peak Correlation Coefficient (CC) as a statistical figure of merit. Further Probability of Detection (PoD) of the pulse compression favourable FMTWI technique has been improved by differential filtering post-processing based scheme that reduces the memory requirement, computational cost as well as complexity.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42118132","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 : 2020-09-10DOI: 10.1088/2633-1357/abb290
S. Kannan, R. Vezhavendhan, S. Kishore, Kamal Varma Kanumuru
The main objective of this study is to characterize the effect of infill percentage, printing orientation and raster angle on ABS samples prepared with 3D printing technology. In this research, samples used were fabricated with two different infill percentages (50% & 75%), 6 different raster patterns and three different orientations. The influence of these parameters on tensile properties were studied with the help of 3D printed samples as per ASTM standard D638 Type IV. From the experimental analysis it was found that the tensile properties were highly anisotropic. Stress strain graphs are plotted for all the samples and the variation of strength with respect to the three parameters are analysed. It was observed that Infill density is directly proportional to mechanical properties. Flat and vertical orientation have better strength and stiffness in comparison with vertical build. The experimental results proved that flat oriented samples exhibited variable strength for changes in raster orientation, other samples have shown minimal changes only.
本研究的主要目的是表征填充百分比、打印方向和光栅角度对采用3D打印技术制备的ABS样品的影响。在这项研究中，使用两种不同的填充百分比（50%和75%）、6种不同的光栅图案和三种不同的取向来制造所用的样品。这些参数对拉伸性能的影响是在根据ASTM标准D638 Type IV的3D打印样品的帮助下研究的。从实验分析中发现，拉伸性能是高度各向异性的。绘制了所有样品的应力-应变图，并分析了强度随三个参数的变化。据观察，填充密度与机械性能成正比。与垂直结构相比，平面和垂直方向具有更好的强度和刚度。实验结果表明，平面取向的样品在光栅取向变化时表现出不同的强度，而其他样品仅表现出最小的变化。
{"title":"Investigating the effect of orientation, infill density with Triple raster pattern on the tensile properties for 3D Printed samples","authors":"S. Kannan, R. Vezhavendhan, S. Kishore, Kamal Varma Kanumuru","doi":"10.1088/2633-1357/abb290","DOIUrl":"https://doi.org/10.1088/2633-1357/abb290","url":null,"abstract":"The main objective of this study is to characterize the effect of infill percentage, printing orientation and raster angle on ABS samples prepared with 3D printing technology. In this research, samples used were fabricated with two different infill percentages (50% & 75%), 6 different raster patterns and three different orientations. The influence of these parameters on tensile properties were studied with the help of 3D printed samples as per ASTM standard D638 Type IV. From the experimental analysis it was found that the tensile properties were highly anisotropic. Stress strain graphs are plotted for all the samples and the variation of strength with respect to the three parameters are analysed. It was observed that Infill density is directly proportional to mechanical properties. Flat and vertical orientation have better strength and stiffness in comparison with vertical build. The experimental results proved that flat oriented samples exhibited variable strength for changes in raster orientation, other samples have shown minimal changes only.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43799490","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 : 2020-09-10DOI: 10.1088/2633-1357/abb291
T. Sivayogan, J. Chow
Purpose: We developed a graphical user interface (GUI) for electron phase-space field trimming using Monte Carlo simulations. This GUI can be used for monitor unit (MU) calculation in electron therapy. Methods: The GUI and electron field trimming algorithm were developed using MATLAB and C code. Phase-space files for the electron fields were generated using the EGSnrc code based on a Varian 21EX Linac with variables of applicator size, field size and energy. Verification of the alogrithm was carried out by comparing the relative output factor, which was used for MU calculation, predicted by Monte Carlo simulations and from actual measurements. Results: Our electron field trimming algorithm was found to be about five times faster than the original Monte Carlo simulation. Clinically, the GUI performed best when using voxel size ≥ 0.3 × 0.3 × 0.3 cm3, and field size larger than 2 cm in radius based on an acceptable deviation of 2%. Conclusion: A GUI for generating irregular field for MU calculation using Monte Carlo simulations was created as a user-friendly tool in electron therapy.
{"title":"Monitor unit calculation in electron therapy using Monte Carlo Simulation: a GUI for the phase-space field trimming","authors":"T. Sivayogan, J. Chow","doi":"10.1088/2633-1357/abb291","DOIUrl":"https://doi.org/10.1088/2633-1357/abb291","url":null,"abstract":"Purpose: We developed a graphical user interface (GUI) for electron phase-space field trimming using Monte Carlo simulations. This GUI can be used for monitor unit (MU) calculation in electron therapy. Methods: The GUI and electron field trimming algorithm were developed using MATLAB and C code. Phase-space files for the electron fields were generated using the EGSnrc code based on a Varian 21EX Linac with variables of applicator size, field size and energy. Verification of the alogrithm was carried out by comparing the relative output factor, which was used for MU calculation, predicted by Monte Carlo simulations and from actual measurements. Results: Our electron field trimming algorithm was found to be about five times faster than the original Monte Carlo simulation. Clinically, the GUI performed best when using voxel size ≥ 0.3 × 0.3 × 0.3 cm3, and field size larger than 2 cm in radius based on an acceptable deviation of 2%. Conclusion: A GUI for generating irregular field for MU calculation using Monte Carlo simulations was created as a user-friendly tool in electron therapy.","PeriodicalId":93771,"journal":{"name":"IOP SciNotes","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45927688","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/abb2b0
S. Yadav, G. Yadav, U. Yadava
Several DNA minor groove binders exhibit numerous therapeutic applications. The crystal structure demonstrating 2,5-bis[4-(N-cyclobutyldiaminomethyl)phenyl]furan binding within the minor groove of DNA has been reported by Simpson et al (2000 Bioorg. Med. Chem. Lett. 10 2593). In the present study, computational investigations on the title compound have been carried out which comprise geometry optimization, HOMO-LUMO, dipole moment, Molecular electrostatic potential(MEP), thermodynamic parameters, and IR assignments using the B3LYP/6-31G** method. The true minimum was long-established by the nonappearance of negative wavenumbers. A comparison of optimized parameters with crystallographic structure demonstrates slight variations in the conformations of the cyclobutyl groups. A small HOMO-LUMO gap indicates the high chemical reactivity and inter molecule charge transferability. The vibrational spectra of the molecule calculated in 400–3800 cm−1 region, reproduce reliable IR assignments. Bearing in mind the high pharmaceutical significance of minor groove binders and a variety of flexible options accessible for lead optimization will be a bountiful ground for the development of drugs targeting minor grooves.
{"title":"Electronic structure and vibrational assignments of 2,5-bis[4-(n-cyclobutyldiaminomethyl)phenyl]furan","authors":"S. Yadav, G. Yadav, U. Yadava","doi":"10.1088/2633-1357/abb2b0","DOIUrl":"https://doi.org/10.1088/2633-1357/abb2b0","url":null,"abstract":"Several DNA minor groove binders exhibit numerous therapeutic applications. The crystal structure demonstrating 2,5-bis[4-(N-cyclobutyldiaminomethyl)phenyl]furan binding within the minor groove of DNA has been reported by Simpson et al (2000 Bioorg. Med. Chem. Lett. 10 2593). In the present study, computational investigations on the title compound have been carried out which comprise geometry optimization, HOMO-LUMO, dipole moment, Molecular electrostatic potential(MEP), thermodynamic parameters, and IR assignments using the B3LYP/6-31G** method. The true minimum was long-established by the nonappearance of negative wavenumbers. A comparison of optimized parameters with crystallographic structure demonstrates slight variations in the conformations of the cyclobutyl groups. A small HOMO-LUMO gap indicates the high chemical reactivity and inter molecule charge transferability. The vibrational spectra of the molecule calculated in 400–3800 cm−1 region, reproduce reliable IR assignments. Bearing in mind the high pharmaceutical significance of minor groove binders and a variety of flexible options accessible for lead optimization will be a bountiful ground for the development of drugs targeting minor grooves.","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":"46100277","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/abba45
Christopher Jellen, C. Nelson, C. Brownell, J. Burkhardt, Miles Oakley
The index of refraction structure constant, Cn2, characterizing the intensity of optical turbulence, describes the disruption of a propagating electromagnetic beam passing through an inhomogeneously heated turbulent environment. In order to improve predictive models, it is critical to develop a deeper understanding of the relationships between environmental parameters and optical turbulence. To that end, an overwater, 890 m scintillometer link was established along the Chesapeake Bay adjacent to the Severn River in Annapolis, Maryland. Specifically, Cn2 data from the scintillometer, as well, as numerous meteorological parameters were collected over the period of approximately 15 months to characterize a scintillometer link in the near-maritime environment. The characteristics of this near-maritime link were distinct from those observed in prior over-land and open ocean links. Further, existing macro-meteorological models for predicting Cn2 from environmental parameters developed for open-ocean links were shown to perform poorly in the near-maritime environment. While the offshore adapted macro-meteorological model demonstrated lower prediction error, this study suggests that new models could be developed to reduce Cn2 prediction error in the near-maritime environment. The complete data set, including Cn2 measurements, and to our knowledge, one of the first to extend beyond one year, is available.
{"title":"Measurement and analysis of atmospheric optical turbulence in a near-maritime environment","authors":"Christopher Jellen, C. Nelson, C. Brownell, J. Burkhardt, Miles Oakley","doi":"10.1088/2633-1357/abba45","DOIUrl":"https://doi.org/10.1088/2633-1357/abba45","url":null,"abstract":"The index of refraction structure constant, Cn2, characterizing the intensity of optical turbulence, describes the disruption of a propagating electromagnetic beam passing through an inhomogeneously heated turbulent environment. In order to improve predictive models, it is critical to develop a deeper understanding of the relationships between environmental parameters and optical turbulence. To that end, an overwater, 890 m scintillometer link was established along the Chesapeake Bay adjacent to the Severn River in Annapolis, Maryland. Specifically, Cn2 data from the scintillometer, as well, as numerous meteorological parameters were collected over the period of approximately 15 months to characterize a scintillometer link in the near-maritime environment. The characteristics of this near-maritime link were distinct from those observed in prior over-land and open ocean links. Further, existing macro-meteorological models for predicting Cn2 from environmental parameters developed for open-ocean links were shown to perform poorly in the near-maritime environment. While the offshore adapted macro-meteorological model demonstrated lower prediction error, this study suggests that new models could be developed to reduce Cn2 prediction error in the near-maritime environment. The complete data set, including Cn2 measurements, and to our knowledge, one of the first to extend beyond one year, is available.","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":"46354391","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/abb933
S. Obilikpa
This paper presents the design and implementation of a robust H-infinity controller on two novel MEMS force sensors. The novel microelectromechanical system (MEMS) sensors incorporated a mechanism that permits tuning of the device’s mechanical stiffness and has been used for the characterization of micro-cantilever and biological tissues. To ensure stability and guaranteed performances, certain specifications such as error tracking, command moderation, disturbance rejection, and robustness in presence of uncertainties, were made and the H-infinity control technique was employed to synthesize robust controllers for the two force sensors. Finally, this robust controller, integral, and PID controllers were implemented on the real systems and their performance in closed-loop were compared.
{"title":"Robust H-infinity control of two novel MEMS force sensors","authors":"S. Obilikpa","doi":"10.1088/2633-1357/abb933","DOIUrl":"https://doi.org/10.1088/2633-1357/abb933","url":null,"abstract":"This paper presents the design and implementation of a robust H-infinity controller on two novel MEMS force sensors. The novel microelectromechanical system (MEMS) sensors incorporated a mechanism that permits tuning of the device’s mechanical stiffness and has been used for the characterization of micro-cantilever and biological tissues. To ensure stability and guaranteed performances, certain specifications such as error tracking, command moderation, disturbance rejection, and robustness in presence of uncertainties, were made and the H-infinity control technique was employed to synthesize robust controllers for the two force sensors. Finally, this robust controller, integral, and PID controllers were implemented on the real systems and their performance in closed-loop were compared.","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":"46759365","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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