scholarly journals Electrospinning of a Copolymer PVDF-co-HFP Solved in DMF/Acetone: Explicit Relations among Viscosity, Polymer Concentration, DMF/Acetone Ratio and Mean Nanofiber Diameter

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3418
Author(s):  
Petr Filip ◽  
Jana Zelenkova ◽  
Petra Peer
Keyword(s):  
Experimental Data ◽  
Master Curve ◽  
Polymer Concentration ◽  
Mean Deviation ◽  
Algebraic Expressions ◽  
Nanofiber Diameter ◽  
The Mean ◽  
Copolymer Poly ◽  
Mutual Relations ◽  
Viscosity Polymer

The process of electrospinning polymer solutions depends on many entry parameters, with each having a significant impact on the overall process and where complexity prevents the expression of their interplay. However, under the assumption that most parameters are fixed, it is possible to evaluate the mutual relations between pairs or triples of the chosen parameters. In this case, the experiments were carried out with a copolymer poly(vinylidene-co-hexafluoropropylene) solved in mixed N,N’-dimethylformamide (DMF)/acetone solvent for eight polymer concentrations (8, 10, 12, 15, 18, 21, 24, and 27 wt.%) and five DMF/acetone ratios (1/0, 4/1, 2/1, 1/1, 1/2). Processing of the obtained data (viscosity, mean nanofiber diameter) aimed to determine algebraic expressions relating both to viscosity and a mean nanofiber diameter with polymer concentration, as well as DMF/acetone ratio. Moreover, a master curve relating these parameters with no fitting factors was proposed continuously covering a sufficiently broad range of concentration as well as DMF/acetone ratio. A comparison of algebraic evaluation with the experimental data seems to be very good (the mean deviation for viscosity was about 2%, while, for a mean nanofiber diameter was slightly less than 10%).

scholarly journals Evaluation of carbide capacity in CaO-based ternary systems at 1773k for refining process

2020 ◽  
Vol 56 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Z.-G. Yu ◽  
H.-Y. Leng ◽  
L.-J. Wang ◽  
K. Chou
Keyword(s):  
Experimental Data ◽  
Present Model ◽  
Value Added ◽  
Ternary Systems ◽  
Mean Deviation ◽  
Contour Lines ◽  
Removal Of Impurities ◽  
The Mean ◽  
Predicted Values ◽  
Special Steels

Refining slags is widely used in the production of high-value-added alloys and special steels. The removal of impurities depends on the mass transfer between the slag-metal interface, and the carbide capacity of the refining slags is crucial to control the carbon content in the final products. A phenomenological model is introduced in this article for the calculation of carbide capacity of different CaO-based ternary refining slags. The contour lines of carbide capacity in CaO-Al2O3- CaF2, CaO-SiO2-CaF2 CaO-SiO2-MnO systems are calculated based on limited experimental data by the present model. The experimental data within the calculation boundary are compared with the predicted values and satisfactory agreements are observed with the mean deviation being 1.4%, 2.3%, and 1.6%, for these three systems respectively. The present model is powerful and flexible in the calculation of carbide capacity of CaO-based ternary refining slags and can be applied to other systems.

scholarly journals Polymer weight determination from numerical and experimental data of the reduced viscosity of polymer in brine

2019 ◽  
Vol 65 (4 Jul-Aug) ◽  
pp. 321
Author(s):  
A. Vega Paz ◽  
F. De J. Guevara Rodríguez ◽  
J. F. Palomeque Santiago ◽  
And N. Victorovna Likhanova
Keyword(s):  
Experimental Data ◽  
Polymer Concentration ◽  
Dynamics Simulation ◽  
Radius Of Gyration ◽  
Trimethyl Ammonium Chloride ◽  
Reduced Viscosity ◽  
The Mean ◽  
Temperature And Pressure ◽  
Vinyl Benzyl ◽  
Poly Acrylamide

The molecular weight of poly[acrylamide-co-vinylpyrrolidone-co-(vinyl benzyl) trimethyl ammonium]chloride is determined from numerical and experimental data of the reduced viscosity of polymer in brine (with 0.1M NaCl) at normal temperature and pressure. The methodology is based on the numerical results of the mean radius of gyration of polymer and reduced viscosity which is derived from the molecular dynamics simulation of the mixture by using the NPT ensemble. The formula of the reduced viscosity as a function of the polymer radius of gyration and the polymer concentration in brine is proposed.

scholarly journals New Perspective for Heat Transfer Evaluation During Film Condensation Inside Tubes

2021 ◽  
Vol 39 (2) ◽  
pp. 390-402
Author(s):  
Yanán Camaraza-Medina
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Reynolds Number ◽  
Single Phase ◽  
Film Condensation ◽  
Mean Deviation ◽  
Two Phase ◽  
Wide Range ◽  
The Mean ◽  
Vertical Tubes

This paper presents the main results of the research developed by the author in his postdoctoral investigations on heat transfer calculations during film condensation inside tubes. The elements studied are combined in an analysis expression that provides a reasonable fit with the available experimental data, which includes a total of 22 fluids, including water, refrigerants and a wide range of organic substances, which condense inside horizontal, inclined and vertical tubes. These experimental data were obtained from the reports of 33 sources. Available data covers tube diameters from 2 to 50 mm, mass flow rates from 3 to 850 kg/(m2s), reduced pressures ranging from 0.0008 to 0.91, values for single-phase from 1 to , Reynolds number for two-phase from 900 to 594390, Reynolds number for single-phase from 65 to 84950 and vapor quality from 0.01 to 0.99. The mean deviation found for the analyzed data for horizontal tubes was 13.4%, while for the inclined and vertical tubes data the mean deviation was 14.9%. In all cases, the agreement of the proposed model is good enough to be considered satisfactory for practical design.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

scholarly journals Correlation between fundus autofluorescence and visual function in patients with cone-rod dystrophy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoru Kanda ◽  
Takumi Hara ◽  
Ryosuke Fujino ◽  
Keiko Azuma ◽  
Hirotsugu Soga ◽  
...  
Keyword(s):  
Visual Field ◽  
Significant Relationship ◽  
Fundus Autofluorescence ◽  
Univariate Analysis ◽  
Retrospective Chart Review ◽  
Mean Deviation ◽  
Wide Field ◽  
The Mean ◽  
The Relationship ◽  
Field Imaging

AbstractThis study aimed to investigate the relationship between autofluorescence (AF) signal measured with ultra-wide field imaging and visual functions in patients with cone-rod dystrophy (CORD). A retrospective chart review was performed for CORD patients. We performed the visual field test and fundus autofluorescence (FAF) measurement and visualized retinal structures with optical coherence tomography (OCT) on the same day. Using binarised FAF images, we identified a low FAF area ratio (LFAR: low FAF/30°). Relationships between age and logMAR visual acuity (VA), central retinal thickness (CRT), central choroidal thickness (CCT), mean deviation (MD) value, and LFAR were investigated. Thirty-seven eyes of 21 CORD patients (8 men and 13 women) were enrolled. The mean patient age was 49.8 years. LogMAR VA and MD were 0.52 ± 0.47 and − 17.91 ± 10.59 dB, respectively. There was a significant relationship between logMAR VA and MD (p = 0.001). LogMAR VA significantly correlated with CRT (p = 0.006) but not with other parameters. Conversely, univariate analysis suggested a significant relationship between MD and LFAR (p = 0.001). In the multivariate analysis, LFAR was significantly associated with MD (p = 0.002). In conclusion, it is useful to measure the low FAF area in patients with CORD. The AF measurement reflects the visual field deterioration but not VA in CORD.

scholarly journals Application of Artificial Intelligence (AI) for Sustainable Highway and Road System

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Md Arifuzzaman ◽  
Muhammad Aniq Gul ◽  
Kaffayatullah Khan ◽  
S. M. Zakir Hossain
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Adhesion Force ◽  
Model Development ◽  
Real Life ◽  
Bayesian Optimization ◽  
Support Vector ◽  
Adhesive Properties ◽  
Bayesian Optimization Algorithm ◽  
The Mean

There are several environmental factors such as temperature differential, moisture, oxidation, etc. that affect the extended life of the modified asphalt influencing its desired adhesive properties. Knowledge of the properties of asphalt adhesives can help to provide a more resilient and durable asphalt surface. In this study, a hybrid of Bayesian optimization algorithm and support vector regression approach is recommended to predict the adhesion force of asphalt. The effects of three important variables viz., conditions (fresh, wet and aged), binder types (base, 4% SB, 5% SB, 4% SBS and 5% SBS), and Carbon Nano Tube doses (0.5%, 1.0% and 1.5%) on adhesive force are taken into consideration. Real-life experimental data (405 specimens) are considered for model development. Using atomic force microscopy, the adhesive strength of nanoscales of test specimens is determined according to functional groups on the asphalt. It is found that the model predictions overlap with the experimental data with a high R2 of 90.5% and relative deviation are scattered around zero line. Besides, the mean, median and standard deviations of experimental and the predicted values are very close. In addition, the mean absolute Error, root mean square error and fractional bias values were found to be low, indicating the high performance of the developed model.

Relationship between mean follow-up intraocular pressure, rates of visual field progression and current target intraocular pressure guidelines

2020 ◽  
pp. bjophthalmol-2020-317406
Author(s):  
Bruna Melchior ◽  
Carlos Gustavo De Moraes ◽  
Jayter S Paula ◽  
George A Cioffi ◽  
Christopher A Girkin ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Visual Field ◽  
Treatment Guidelines ◽  
Evaluation Study ◽  
Mean Deviation ◽  
Racial Groups ◽  
Current Guideline ◽  
Registration Number ◽  
The Mean

AimsTo investigate if eyes presenting intraocular pressure (IOP) within the limits of current guideline-driven target IOP indeed experience slow rates of glaucomatous visual field (VF) progression.MethodsA total of 8598 24-2 VF tests from 603 eyes from the African Descent and Glaucoma Evaluation Study with manifest glaucoma were included. The sample was split into three groups based on baseline VF mean deviation (MD): G1 (better than −5.0 dB), G2 (−5.0 to −10 dB) and G3 (worse than −10 dB). We investigated the relationship between existing target IOP guidelines and rates of MD progression in these groups.ResultsFor stable eyes, the medians and IQR of the mean follow-up IOP were G1=15.0 mmHg (IQR: 13.1 to 17.7), G2=13.2 mmHg (IQR: 11.6 to 14.3) and G3=11.9 mmHg (IQR: 10.1 to 13.8) (p<0.01). When considering the mean follow-up IOP within the limits proposed by current guidelines, the median MD slopes were: −0.20 dB/y (IQR: −0.43 to −0.02) for G1<21 mmHg, −0.19 dB/y (IQR: −0.51 to −0.01) for G2<18 mmHg and −0.15 dB/y (IQR: −0.47 to 0.05) for G3<15 mmHg (p=0.63). There were no significant differences between racial groups.ConclusionIn a sample of patients with manifest glaucoma, despite substantial variability between eyes, adherence to treatment guidelines helped slow the rates of global VF progression at various stages of disease.Trial registration numberclinicaltrials.gov Identifier: NCT00221923.

Moments of the mean deviation

Biometrika ◽  
1954 ◽  
Vol 41 (3-4) ◽  
pp. 541-542
Author(s):  
A. R. KAMAT
Keyword(s):  
Mean Deviation ◽  
The Mean

The Bootstrap-Method: Discussion and Proposal for Improvement / Das bootstrap-Verfahren: Diskussion und Verbesserungsvorschlag

1998 ◽  
Vol 217 (1) ◽  
Author(s):  
Hans Schneeberger
Keyword(s):  
Bootstrap Method ◽  
Law School ◽  
Mean Deviation ◽  
Alternative Method ◽  
Doubling Method ◽  
The Mean ◽  
The Bootstrap Method

SummaryWith Efron’s law-school example the bootstrap method is compared with an alternative method, called doubling. It is shown, that the mean deviation of the estimator is always smaller for the doubling method.

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