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

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.

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>

Study of the Fixing Process of Threaded Connections By Anaerobic Materials

2018 ◽  
pp. 122-127
Author(s):  
P. P. Fedirko ◽  
V. O. Krol ◽  
V. S. Bonchyk
Keyword(s):  
Room Temperature ◽  
Glycol Ethers ◽  
Threaded Connections ◽  
Torque Wrench ◽  
Mechanical Methods ◽  
Study Results ◽  
Polyalkylene Glycol ◽  
High Conversion Rate ◽  
Anaerobic Adhesives ◽  
Protection Of The Metal

The article presents the study results of the anaerobic materials effect on the strength of threaded connections in the repair of machinery and equipment. Their use is the simplest, most economical and reliable method of fixing and restoring threaded connections. The basis of the anaerobic compositions is polymerization compounds of the acrylic series, most often dimethacrylic and polyalkylene glycol ethers, which are characterized by a high conversion rate into spatially cross-linked polymers. Unlike mechanical methods of fixation and recovery, anaerobic materials completely fill the space between the threads of the spiral. This significantly increases the friction between the parts of the connection, improves the protection of the metal of the interface against corrosion, increases the torque when unscrewing in relation to the tightening torque, increases the resistance of the connection to the action of vibration, shock, shock loads. For the research, anaerobic thread locks were purchased, which were tested according to the same procedure and, after 24 hours at room temperature, each connection was clamped in a vice in turn so that the head of the torque wrench captures only the top nut, which had to be unscrewed. The rate of hardening of anaerobic adhesives is influenced by the size of the gaps between the combined surfaces, temperature, cleaning quality, the nature of the coating, etc. It has been established that the presence of polymerized anaerobic materials in the contact zone of parts significantly increases the strength of the joints. The conducted studies allowed to verify in practice the conformity of the tested anaerobic clamps of threaded connections to the stated parameters, to delineate the scope of their application. So, anaerobic adhesives for fixing threaded connections allow you to fix screws, nuts, bolts and pins to protect against loosening and loosening due to vibration

Cellulose Nanofibrils-based Hydrogels for Biomedical Applications: Progresses and Challenges

2020 ◽  
Vol 27 (28) ◽  
pp. 4622-4646 ◽  
Author(s):  
Huayu Liu ◽  
Kun Liu ◽  
Xiao Han ◽  
Hongxiang Xie ◽  
Chuanling Si ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metal Ion ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Cellulose Nanofibrils ◽  
Wound Dressings ◽  
Preparation Methods ◽  
Tissue Scaffold ◽  
Surface Areas ◽  
Mechanical Methods

Background: Cellulose Nanofibrils (CNFs) are natural nanomaterials with nanometer dimensions. Compared with ordinary cellulose, CNFs own good mechanical properties, large specific surface areas, high Young's modulus, strong hydrophilicity and other distinguishing characteristics, which make them widely used in many fields. This review aims to introduce the preparation of CNFs-based hydrogels and their recent biomedical application advances. Methods: By searching the recent literatures, we have summarized the preparation methods of CNFs, including mechanical methods and chemical mechanical methods, and also introduced the fabrication methods of CNFs-based hydrogels, including CNFs cross-linked with metal ion and with polymers. In addition, we have summarized the biomedical applications of CNFs-based hydrogels, including scaffold materials and wound dressings. Results: CNFs-based hydrogels are new types of materials that are non-toxic and display a certain mechanical strength. In the tissue scaffold application, they can provide a micro-environment for the damaged tissue to repair and regenerate it. In wound dressing applications, it can fit the wound surface and protect the wound from the external environment, thereby effectively promoting the healing of skin tissue. Conclusion: By summarizing the preparation and application of CNFs-based hydrogels, we have analyzed and forecasted their development trends. At present, the research of CNFs-based hydrogels is still in the laboratory stage. It needs further exploration to be applied in practice. The development of medical hydrogels with high mechanical properties and biocompatibility still poses significant challenges.

On the Influence of the Slot Orifice in Diesel Common Rail Nozzle

2018 ◽  
Vol 11 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Giancarlo Chiatti ◽  
Ornella Chiavola ◽  
Fulvio Palmieri ◽  
Roberto Pompei
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Experimental Analysis ◽  
Common Rail ◽  
Spray Angle ◽  
The Novel ◽  
Hydraulic Behavior ◽  
Reference Information ◽  
Light Duty ◽  
Set Up

Background:The paper deals with a diesel common rail nozzle in which a novel orifice layout is implemented.Objective:Its influence on the nozzle mechanical-hydraulic behavior and on the spray shape transient development is experimentally investigated.Methods:In the research, a solenoid injector for light duty diesel engines is equipped with the novel nozzle prototype and tested. The prototype layout is described, pointing out the features of the nozzle orifices, in which a Slot cross-section is adopted; the investigation is accomplished extending the hydraulic tests and the spray visualizations to a reference nozzle with standard holes. The influence of the hole layout on the mechanical-hydraulic behavior of the nozzle is assessed by experimental analysis based on the rate of injection measurement, in comparison with the reference nozzle. Once the hydraulic behavior of the novel nozzle has been characterized in terms of mass flow rate, the slot influence on the spray shape is assessed analyzing the macroscopic features such as the penetration distance and the spray angle, in non evaporative conditions. The study is carried out under transient injection conditions, for different injection pressures, up to 1400 bar.Results:The results on spray characteristics also provide reference information to set up spray models suited to take the Slot orifice into account.

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.

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