scholarly journals Effect of Punch Surface Grooves on Microformability of AA6063 Backward Microextrusion

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1299
Author(s):  
Tatsuya Funazuka ◽  
Kuniaki Dohda ◽  
Tomomi Shiratori ◽  
Ryo Hiramiya ◽  
Ikumu Watanabe
Keyword(s):  
Surface Properties ◽  
Material Properties ◽  
Size Effects ◽  
Groove Depth ◽  
The Other ◽  
Extrusion Force ◽  
Micro Scale ◽  
Backward Extrusion ◽  
Tool Surface ◽  
Frictional Effects

In order to apply conventional forming processes at the micro scale, the size effects caused by material properties and frictional effects must be taken into account. In this research, the effects of tool surface properties such as punch surface grooves on microextrudability, assessed using extrusion force, shape of the extrusion, and Vickers hardness, were investigated using an AA6063 billet. Microscale grooves of 5 to 10 µm were fabricated on the punch surface. The extrusion force increased rapidly as the stroke progressed for all the grooves. Comparing the product geometries showed that, the smaller the groove size, the lower the adhesion and the longer the backward extrusion length. The results of material analysis using EBSD showed that a 5 µm groove depth punch improved the material flowability and uniformly introduced more strain. On the other hand, material flowability was reduced and strain was applied nonuniformly when a mirror-finish tool was used. Therefore, the tribology between the tool and the material was controlled by changing the surface properties of the punch to improve formability.

On Slip Inception and Static Friction for Smooth Dry Contact

2014 ◽  
Vol 81 (12) ◽  
Author(s):  
Xi Shi
Keyword(s):  
Shear Strength ◽  
Contact Area ◽  
Material Properties ◽  
Static Friction ◽  
Friction Model ◽  
Interfacial Bonding ◽  
The Other ◽  
Material Failure ◽  
Bonding Failure ◽  
Dry Contact

Slip inception mechanism is very important for modeling of static friction and understanding of some experimental observations of friction. In this work, slip inception was treated as a local competence of interfacial bonding failure and weaker material failure. At any contacting point, if bond shear strength is weaker than softer material shear strength, slip inception is governed by interfacial bonding failure. Otherwise, it is governed by softer material failure. Considering the possible co-existence of these two slip inception mechanisms during presliding, a hybrid static friction model for smooth dry contact was proposed, which indicates that the static friction consists of two components: one contributed by contact area where bonding failure is dominant and the other contributed by contact area where material failure is dominant. With the proposed static friction model, the effects of contact pressure, the material properties, and the contact geometry on static friction were discussed.

scholarly journals Early development of corn seedlings primed with synthetic tenorite nanofertilizer

2020 ◽  
Vol 42 ◽  
Author(s):  
Michel Esper Neto ◽  
David W. Britt ◽  
Kyle Alan Jackson ◽  
Alessandro Lucca Braccini ◽  
Tadeu Takeyoshi Inoue ◽  
...  
Keyword(s):  
Seed Germination ◽  
Size Effects ◽  
Seed Priming ◽  
Seedling Development ◽  
Cuo Nanoparticles ◽  
The Other ◽  
Corn Seed ◽  
Cu Toxicity ◽  
Germination And Growth

Abstract: Fertilizer formulation alternatives that avoid unnecessary losses and environmental impacts are being investigated in agricultural management. Seed priming with nanofertilizers prior to planting, reduces concerns about non-target dispersion; however, priming formulations and concentrations must be carefully selected to avoid undesired effects. Here, seed germination and seedling development were evaluated after seed priming with CuO nanoparticles (NPs), CuO bulk and CuCl2. The seeds were immersed in priming solutions of 0, 20, 40, 80 and 160 mg.L−1 Cu for the three Cu sources. Following 8 hours priming, the seeds were evaluated for germination and vigor (first germination count). Root and shoot lengths were measured as well as shoot and root dry biomass. The copper NP did not show any toxic effects on corn seed germination and growth, and also promoted higher biomass when compared to the other Cu sources. On the other hand, CuCl2 primed seeds exhibited Cu-toxicity in roots and shoots for all concentrations tested. Bulk Cu priming results indicated the better role of NPs size effects. These findings support NP-seed priming as an alternative to delivery of essential micronutrients, such as copper, to corn seedlings.

Effect of Electrolytic Temperature on Nano-Hydroapatite Deposition on ASD Bioceramic Films

2014 ◽  
Vol 609-610 ◽  
pp. 64-67
Author(s):  
Xiao Ni Ma ◽  
Li Hua Zhang ◽  
Li Xue Zheng ◽  
Zhan Hua Yang ◽  
Qing Gao ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Process Parameters ◽  
The Other ◽  
Porous Films ◽  
Film Properties ◽  
High Quality ◽  
Quality Performance ◽  
Micro Scale ◽  
Novel Technique ◽  
Leading Role

Anodic spark deposition (ASD) is a novel technique to deposit bioceramic films on the surface of titanium (Ti) and its alloys, and the films prepared with nano/micro scale pores are characterized by high-quality performance for dental implant. Among the process parameters, electrolyte provides a leading role owing to its vital influence not only on the films chemistry but also on the electrical conductivity of the circuit, which affects the film properties. In this study, titania porous films were synthesized by ASD and the effect of electrolytic temperature on microstructure and chemical composition of the films was studied. The results show that the electrolytic temperature could significantly influence the surface topography, thickness and chemical composition of the oxidation films produced by ASD and, therefore, determined the layered hydroapatite (HA) deposition as the other process parameters were fixed.

Scatter in Dwell Time Cracking for a Ni-Based Superalloy in Combination With Overloads

2015 ◽  
Author(s):  
Erik Storgärds ◽  
Jonas Saarimäki ◽  
Kjell Simonsson ◽  
Sören Sjöström ◽  
David Gustafsson ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Crack Growth ◽  
Material Properties ◽  
Inconel 718 ◽  
Dwell Time ◽  
The Other ◽  
Surface Cracks ◽  
Multiple Tests ◽  
Material Data

In this paper scatter in crack growth for dwell time loadings in combination with overloads has been investigated. Multiple tests were performed for surface cracks at 550°C in the commonly used high temperature material Inconel 718. The test specimens originate from two different batches which also provides for a discussion of how material properties affect the dwell time damage and overload impact. In combination with these tests an investigation of the microstructure was also carried out, which shows how it influences the growth rate. The results from this study show that, in order to take overloads into consideration when analysing spectrum loadings containing dwell times, one needs a substantial amount of material data available as the scatter seen from one batch to the other is of significant proportions.

Comparison of Four Surfactants: In Vitro Surface Properties and Responses of Preterm Lambs to Treatment at Birth

PEDIATRICS ◽  
1987 ◽  
Vol 79 (1) ◽  
pp. 38-46
Author(s):  
Machiko Ikegami ◽  
Yotaro Agata ◽  
Tarek Elkady ◽  
Mikko Hallman ◽  
David Berry ◽  
...  
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Surface Adsorption ◽  
Soluble Proteins ◽  
The Other ◽  
Clinical Responses ◽  
Spreading Rates ◽  
Surface Spreading

Natural sheep surfactant, rabbit surfactant, human surfactant, and surfactant TA were compared for in vitro surface properties and for responses of preterm lambs to treatment. Equivalent amounts of sheep, rabbit, and human surfactants were needed to lower the surface tension to less than 10 dynes/cm, whereas four times less surfactant TA similarly lowered the surface tension. Surface-spreading rates were similar for the surfactants. The surface adsorption of the batch of human surfactant tested was much slower than was adsorption of the other surfactants. Ventilation was significantly improved in all surfactant-treated lambs relative to the control lambs, indicating the general efficacy of the surfactant treatments. Overall, surfactant TA had the best in vitro characteristics, yet the preterm lambs treated at birth with surfactant TA had lower Po2 values and higher ventilatory requirements than did the sheep surfactant-treated lambs. The in vivo responses to rabbit surfactant were intermediate between the responses to sheep surfactant and to surfactant TA. Human surfactant resulted in the least effective clinical response. More of the phosphatidylcholine associated with human surfactant and surfactant TA was lost from the alveoli and lung tissue after four hours of ventilation than was lost from sheep or rabbit surfactant-treated lambs. More intravascular radiolabeled albumin leaked into the alveoli of the surfactant TA-treated lambs than sheep or rabbit surfactant-treated. lambs. The four surfactants also had different sensitivities to the effects on minimum surface tensions of the soluble proteins present in alveolar washes. The study demonstrates that the range of clinical responses was not predictable based on the in vitro surface properties that we measured. The surfactants behaved differently with respect to loss from the lungs and sensitivity to soluble proteins. Factors other than surface properties are important for the in vivo responses to surfactant treatments.

Flexural Properties and Polished Surface Characteristics of a Structural Colored Resin Composite

2021 ◽  
Author(s):  
K Mizutani ◽  
R Ishii ◽  
T Takamizawa ◽  
S Shibasaki ◽  
H Kurokawa ◽  
...  
Keyword(s):  
Surface Properties ◽  
Resin Composite ◽  
Surface Characteristics ◽  
The Other ◽  
Polished Surface ◽  
Flexural Properties ◽  
Strong Positive Correlation ◽  
Resin Composites ◽  
Diamond Bur ◽  
Flexible Disk

SUMMARY Objective: The aim of this study was to determine the flexural properties and surface characteristics of a structural colored resin composite after different finishing and polishing methods, in comparison to those of conventional resin composites. Methods and Materials: A structural color resin composite, Omnichroma (OM, Tokuyama Corp, Chiyoda City, Tokyo, Japan), and two comparison resin composites, Filtek Supreme Ultra (FS, 3M, St Paul, MN, USA) and Tetric EvoCeram (TE, Ivoclar Vivadent, Schaan, Liechtenstein), were used. The flexural properties of the resin composites were determined in accordance with the ISO 4049 specifications. For surface properties, 70 polymerized specimens of each resin composite were prepared and divided into seven groups of 10. Surface roughness (Sa), gloss (GU), and surface free energy (SFE) were investigated after the following finishing and polishing methods. Three groups of specimens were finished with a superfine-grit diamond bur (SFD), and three with a tungsten carbide bur (TCB). After finishing, one of the two remaining groups was polished with a one-step silicone point (CMP), and the other with an aluminum oxide flexible disk (SSD). A group ground with SiC 320-grit was set as a baseline. Results: The average flexural strength ranged from 116.6 to 142.3 MPa in the following order with significant differences between each value: FS > TE > OM. The average E ranged from 6.8 to 13.2 GPa in the following order with significant differences between each value: FS > TE > OM. The average R ranged from 0.77 to 1.01 MJ/mm3 in the following order: OM > FS > TE. The Sa values of the OM groups polished with CMP and SSD were found to be significantly lower than those of the other resin composites, regardless of the finishing method. The GU values appeared to be dependent on the material and the finishing method used. The OM specimens polished with SSD showed significantly higher GU values than those polished with CMP. Most of the resin composites polished with SSD demonstrated significantly higher γS values compared to the other groups. Extremely strong negative correlations between Sa and GU in the combined data from the three resin composites and each resin composite and between Sa and γS in the OM specimens were observed; GU showed a strong positive correlation with γS in the same material. Conclusion: These findings indicate that both flexural and surface properties are material dependent. Furthermore, the different finishing and polishing methods used in this study were observed to affect the Sa, GU, and SFE of the resin composites.

Surface Modification of a-C:H(N) Thin Films by Plasma Treatment

2005 ◽  
Vol 11 (S03) ◽  
pp. 162-165 ◽  
Author(s):  
L. von Mühlen ◽  
R. A. Simao ◽  
C. A. Achete
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Optical Properties ◽  
Surface Modification ◽  
Surface Chemistry ◽  
Plasma Treatment ◽  
Surface Properties ◽  
Functional Groups ◽  
Material Properties ◽  
Modify Surface

Surface chemistry and topography of materials are generally preponderant factors in a series of material properties, such as adhesion, wettability, friction and optical properties [1]. Wettability of films, for example, can be altered significantly by modifying its surface roughness and also by incorporating functional groups. Plasma treatment is a powerful and versatile way to modify surface properties of amorphous nitrogen-incorporated carbon thin films (a-C:H(N)) and obtain materials with improved properties, once it is possible to modify the surfaces in a controlled way by specific settings of plasma conditions. [2 - 4]

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