Elevation/Azimuth Propagation Angle Measurements Using Five-Port Wave Correlators

2006 ◽  
Author(s):  
Van Yem Vu ◽  
A. Judson Braga ◽  
Bernard Huyart ◽  
Xavier Begaud ◽  
Nguyen Bich Huyen
Keyword(s):  
Propagation Angle ◽  
Angle Measurements

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

A COMPARISON OF SPRAY ANGLE MEASUREMENTS USING OPTICAL AND MECHANICAL METHODS

2010 ◽  
Vol 20 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Yudaya R. Sivathanu ◽  
Jongmook Lim ◽  
Bill Wallace ◽  
Roger Seei
Keyword(s):  
Spray Angle ◽  
Angle Measurements ◽  
Mechanical Methods

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

Spindle Angle Measurements

BIO-PROTOCOL ◽  
2013 ◽  
Vol 3 (19) ◽  
Author(s):  
Julien Cau ◽  
Nathalie Morin ◽  
Guillaume Bompard
Keyword(s):  
Angle Measurements

Feasibility of an iPhone-based application for knee joint goniometry during gait in a stroke patient (Preprint)

2018 ◽  
Author(s):  
Claudia Nava ◽  
Patrizio Sale ◽  
Vittorio Leggero ◽  
Simona Ferrante ◽  
Cira Fundaro' ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Stroke Patient ◽  
Reference Method ◽  
Flexion Angle ◽  
Good Reliability ◽  
Rater Reliability ◽  
Maximum Extension ◽  
Angle Measurements ◽  
Hemiparetic Gait ◽  
Flexion Extension

BACKGROUND In recent years, different smartphone apps have been validated for joint goniometry, but none for goniometric assessment of gait after stroke. OBJECTIVE The aims of our work were to assess:1) to assess intra-rater reliability of an image-based goniometric app – DrGoniometer- in the measurement of the extension, flexion angles and range of motion of the knee during the hemiparetic gait of a stroke patient; (2) its validity comparing to the reference method (electrogoniometer) for flexion-extension excursion measurements; and the intra-rater agreement in the choice of the video frames. METHODS An left-hemiparetic inpatient following haemorrhagic stroke was filmed using the app while walking on a linear path. An electrogoniometer was fixed on the medial face of the affected knee in order to record the dynamic goniometry during gait. Twenty-one raters, blinded to measurements, were recruited to rate knee angle measurements from video acquired with DrGoniometer. Each rater repeated the same procedure twice, the second one at least one day after the first measure. RESULTS Results showed that flexion angle measurements are reliable (ICC95%=0.66, 0.34;0.85; SEM=4°), and adequately precise (CV=14%). Extension angles measurements demonstrated moderate reliability and higher degree of variation (ICC=0.51, 0.09;0.77; SEM 4°; CV=53%). ROM values were: ICC=0.23 (-0.21;0.60); CV=20%. Accuracy of DrGoniometer compared to the electrogoniometer was 7.3±4.7°. The selection of maximum extension frame revealed an accordance of 58% and 72% within a range of ±5 or ±10 frames, respectively; while the best flexion frame reported 86% of agreement for both range of 5 and 10 frames. CONCLUSIONS The results demonstrated moderate to good reliability concerning the maximum extension and flexion angles, while assessing ROM DrGoniometer showed poor intra-rater reliability. Flexion angle measurements seemed to be reliable according to ICC and SEM values and more precise with a limited dispersion of results DrGoniometer revealed a good accuracy in the measurement of range of motion. The agreement of the maximal extension frame was anyway adequate within 5 frames (59%) and noticeably increased within 10 frames (72%). In conclusion, DrGoniometer was found to be a valid and reliable method for assessing knee angles during hemiparetic gait. Further studies are necessary to investigate inter-rater reliability and confirm our results.

scholarly journals On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1643
Author(s):  
Ricardo Donate ◽  
María Elena Alemán-Domínguez ◽  
Mario Monzón
Keyword(s):  
Surface Properties ◽  
Enzymatic Degradation ◽  
Oxygen Plasma ◽  
Physicochemical Characterization ◽  
Surface Treatments ◽  
Carboxyl Groups ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Angle Measurements ◽  
3D Printed

Surface modification of 3D-printed PLA structures is a major issue in terms of increasing the biofunctionality and expanding the tissue engineering applications of these parts. In this paper, different exposure times were used for low-pressure oxygen plasma applied to PLA 3D-printed scaffolds. Alkali surface treatments were also evaluated, aiming to compare the modifications introduced on the surface properties by each strategy. Surface-treated samples were characterized through the quantification of carboxyl groups, energy-dispersive X-ray spectroscopy, water contact angle measurements, and differential scanning calorimetry analysis. The change in the surface properties was studied over a two-week period. In addition, an enzymatic degradation analysis was carried out to evaluate the effect of the surface treatments on the degradation profile of the 3D structures. The physicochemical characterization results suggest different mechanism pathways for each type of treatment. Alkali-treated scaffolds showed a higher concentration of carboxyl groups on their surface, which enhanced the enzymatic degradation rate, but were also proven to be more aggressive towards 3D-printed structures. In contrast, the application of the plasma treatments led to an increased hydrophilicity of the PLA surface without affecting the bulk properties. However, the changes on the properties were less steady over time.

scholarly journals Modification of PLA Scaffold Surface for Medical Applications

2021 ◽  
Vol 11 (4) ◽  
pp. 1815
Author(s):  
Michał Młotek ◽  
Agnieszka Gadomska-Gajadhur ◽  
Aleksandra Sobczak ◽  
Aleksandra Kruk ◽  
Michalina Perron ◽  
...  
Keyword(s):  
Dielectric Barrier Discharge ◽  
Phase Inversion ◽  
Barrier Discharge ◽  
Polar Component ◽  
Medical Applications ◽  
Specific Chemical ◽  
Dielectric Barrier ◽  
Angle Measurements ◽  
Wet Phase Inversion ◽  
Materials Used

Materials used for medical applications (e.g., the cellular scaffold) should have not only the specific chemical composition, but the surface layer properties as well. For this reason, a method which enables an increase in the number of pores, wettability of the surface, and improvement the conditions of nutrient transportation into the membrane is being studied. The plasma of a dielectric barrier discharge was applied for the surface modification of polylactide obtained by dry or wet phase inversion. The plasma-modified surface was analyzed by contact angle measurements with water and diiodomethane. The surface free energy (SFE) was calculated by the Owens–Wendt method. The highest SFE and its polar component (67.6 mJ/m2 and 39.5 mJ/m2, respectively) were received when the process was conducted in an Ar + CO2 gas mixture with a discharge power of 20 W. The purpose of this research was to increase the wettability and porosity of the membrane’s surface. It can be concluded that the dielectric barrier discharge can effectively change the surface of the polylactide membranes, and that the structure of the modified membranes was not damaged during modification. The process of modification was easier for the membranes made by dry phase inversion. These materials had higher SFE values after the modification.

scholarly journals Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3888
Author(s):  
Johanna Maier ◽  
Christian Vogel ◽  
Tobias Lebelt ◽  
Vinzenz Geske ◽  
Thomas Behnisch ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Polyamide 6 ◽  
Thermoplastic Composites ◽  
Efficient Production ◽  
Angle Measurements ◽  
Small Series ◽  
Contact Angle Measurements ◽  
Static Tensile ◽  
Pre Treatment ◽  
Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

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