Cracking of porcelain coatings bonded to metal substrates of different modulus and hardness

2001 ◽  
Vol 16 (5) ◽  
pp. 1471-1478 ◽  
Author(s):  
Hong Zhao ◽  
Xiaozhi Hu ◽  
Mark B. Bush ◽  
Brian R. Lawn
Keyword(s):  
Critical Loads ◽  
Lower Surface ◽  
Bilayer System ◽  
Pd Alloy ◽  
Metal Yield ◽  
Radial Cracks ◽  
Substrate Hardness ◽  
Preceding Study ◽  
Alloy Metal

A preceding study of contact damage in a bilayer system consisting of a porcelain coating on a stiff Pd-alloy substrate is here expanded to investigate the role of substrate modulus and hardness. Bilayers are made by fusing the same dental porcelain onto Co-, Pd-, and Au-alloy metal bases. Indentations are made on the porcelain surfaces using spheres of radii 2.38 and 3.98 mm. Critical loads to initiate cone fracture at the top surface of the porcelain and yield in the substrate below the contact are measured as a function of porcelain thickness. Radial cracks form at the lower surface of the coating once the substrate yield is well developed. By virtue of its controlling role in the metal yield process, substrate hardness is revealed to be a key material parameter—substrate modulus plays a secondary role. A simple elasticitybased analysis for predetermining critical loads for a given brittle/plastic bilayer system is presented.

Embedded Interface Regulates Underwater Actuation of Solvent-Responsive Soft Grippers

Soft Matter ◽  
2021 ◽  
Author(s):  
Rajesh Kumar Meena ◽  
Sridatta Rapaka ◽  
Raghunandan Pratoori ◽  
Ratna Kumar Annabattula ◽  
Pijush Ghosh
Keyword(s):  
Thin Films ◽  
Polymer Thin Films ◽  
Bilayer System

In this work, we report the role of an embedded interface between two polymer thin films in determining the overall folding and actuation characteristics of a bilayer system applied for...

Confined Gas Atomization: The Role of the Melt Delivery Tube in Particle Size Control

1986 ◽  
Vol 80 ◽  
Author(s):  
R. V. Raman
Keyword(s):  
Unique Feature ◽  
Size Control ◽  
Lower Surface ◽  
Spherical Particles ◽  
Gas Atomization ◽  
Reactive Elements ◽  
Delivery Tube ◽  
Atomization Process ◽  
Rapidly Solidified

AbstractGas atomization is one of the key processes used for the production of rapidly solidified materials. The unique feature of the gas atomization process is its capability to form spherical powders of multicomponent alloys containing reactive elements. Spherically shaped powder is specified in the secondary processing operations used in a number of applications. This requirement has resulted from the higher flow rate, better packing density, and lower surface area obtained in spherical particles compared to irregularly shaped particles.

scholarly journals Thermodynamics of manganese oxides: Sodium, potassium, and calcium birnessite and cryptomelane

2017 ◽  
Vol 114 (7) ◽  
pp. E1046-E1053 ◽  
Author(s):  
Nancy Birkner ◽  
Alexandra Navrotsky
Keyword(s):  
Surface Energy ◽  
Surface Area ◽  
Oxidation State ◽  
Manganese Oxides ◽  
Lower Surface ◽  
Surface Energies ◽  
Surface Areas ◽  
Bulk Thermodynamics ◽  
Lower Surface Energy

Manganese oxides with layer and tunnel structures occur widely in nature and inspire technological applications. Having variable compositions, these structures often are found as small particles (nanophases). This study explores, using experimental thermochemistry, the role of composition, oxidation state, structure, and surface energy in the their thermodynamic stability. The measured surface energies of cryptomelane, sodium birnessite, potassium birnessite and calcium birnessite are all significantly lower than those of binary manganese oxides (Mn3O4, Mn2O3, and MnO2), consistent with added stabilization of the layer and tunnel structures at the nanoscale. Surface energies generally decrease with decreasing average manganese oxidation state. A stabilizing enthalpy contribution arises from increasing counter-cation content. The formation of cryptomelane from birnessite in contact with aqueous solution is favored by the removal of ions from the layered phase. At large surface area, surface-energy differences make cryptomelane formation thermodynamically less favorable than birnessite formation. In contrast, at small to moderate surface areas, bulk thermodynamics and the energetics of the aqueous phase drive cryptomelane formation from birnessite, perhaps aided by oxidation-state differences. Transformation among birnessite phases of increasing surface area favors compositions with lower surface energy. These quantitative thermodynamic findings explain and support qualitative observations of phase-transformation patterns gathered from natural and synthetic manganese oxides.

The role of the color of the substratum on the initiation of the probing behavior in Myzus persicae (Sulzer) and Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae)

1990 ◽  
Vol 68 (4) ◽  
pp. 694-698 ◽  
Author(s):  
Yvan Pelletier
Keyword(s):  
Myzus Persicae ◽  
Green Peach Aphid ◽  
Lower Surface ◽  
Aphid Species ◽  
Macrosiphum Euphorbiae ◽  
Potato Leaf ◽  
Potato Aphid ◽  
Probing Behavior

Twenty-five colors were evaluated for their effect on the initiation of probing behavior in the green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas). The proportion of aphids of both species initiating probing behavior was maximum on green, yellow, or orange and lowest on purple, blue, white, or black. The time taken by individual aphids to begin probing was shorter for M. persicae than for M. euphorbiae but was essentially unaffected by colors. A larger proportion of both aphid species probed on the lower surface of potato (var. Kathadin) leaflet compared with the upper surface. The proportion of aphids initiating probing was the same on the lower surface of a potato leaf and on paper similar in color, indicating that the color of the substratum is determinant in the initiation of feeding for those aphids.

scholarly journals Role of Palladium in Hydrogen Absorption of Ti-Pd Alloy

1980 ◽  
Vol 29 (12) ◽  
pp. 622-628
Author(s):  
Toshio Fukuzuka ◽  
Kazutoshi Shimogori ◽  
Hiroshi Satoh
Keyword(s):  
Hydrogen Absorption ◽  
Pd Alloy

Modeling of effects of adhesive interlayers on contact-induced radial cracking in brittle coatings on substrates

2003 ◽  
Vol 18 (6) ◽  
pp. 1481-1486 ◽  
Author(s):  
Chun-Hway Hsueh ◽  
Jong Ho Kim ◽  
Do Kyung Kim
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Critical Load ◽  
Elastic Foundation ◽  
Critical Loads ◽  
Glass Substrates ◽  
Adhesive Interlayer ◽  
Semiempirical Equation ◽  
Radial Cracks ◽  
Fitting Parameters

The effects of soft adhesive interlayers on contact-induced radial cracking in brittle coatings on supporting substrates were investigated recently. A semiempirical equation for the critical load to initiate radial cracking was derived, which used three fitting parameters obtained by comparison with the finite element results. An analytical model is derived in the present study to illustrate the effects of adhesive interlayers. This is achieved by adopting the analogy between the coating/substrate system and a plate on an elastic foundation. In the presence of an adhesive interlayer, the interlayer/substrate bilayer is treated as the effective elastic foundation. The effective modulus of foundation for the bilayer is derived, and the solution for coating/interlayer/substrate systems can be obtained from the existing solution for coating/substrate systems by replacing the modulus of foundation. Specific results are calculated for critical loads to initiate radial cracks in silicon coatings bonded by adhesive interlayers of different materials and thicknesses to glass substrates. The present analytical solution provides an alternative other than the existing semiempirical equation in predicting the effects of adhesive interlayers.

scholarly journals Comment: Trade Politics—A Debate

1994 ◽  
Vol 15 ◽  
pp. 89-97 ◽  
Author(s):  
John T. Passé-Smith
Keyword(s):  
Fast Track ◽  
Major Change ◽  
Presidential Power ◽  
White House ◽  
Trade Politics ◽  
Zero Sum ◽  
Trade Deals ◽  
The Relationship ◽  
Preceding Study

The preceding study by Byron W. Daynes and Glen Sussman is valuable in that it points to the complexity of trade and of trade legislation, highlighting the role of presidential fast-track authority within that process. Unfortunately, the authors overstate the case for the waxing of presidential power, choosing to view the evolving relationship as a zero-sum game. The reality is that major trade deals such as those in which fast-track authority is utilized are so complex and politically sensitive that the White House and Congress must work together to achieve success. The evolving relationship is one of managed conflict, not open hostility. The fast-track mechanism does constitute a major change in the relationship between the legislative and executive branches, as the authors document, but change does not automatically mean that the executive is sacking the legislative.

Doctor Faustus and A Shrew

PMLA ◽  
1947 ◽  
Vol 62 (4) ◽  
pp. 950-957
Author(s):  
Raymond A. Houk
Keyword(s):  
Original Version ◽  
Common Source ◽  
Doctor Faustus ◽  
Preceding Study

This study of Christopher Marlowe's The Tragicall Historie of Doctor Faustus and The Taming of a Shrew is related to the preceding study on “Shakespeare's Shrew and Greene's Orlando” in that both involve parallels between A Shrew and contemporary plays—parallels which have been thought by H. D. Sykes and others to involve Samuel Rowley in the rôle of a contributor to each. Instead of such a common author a theory of common sources in earlier versions of the plays is herein maintained. Shakespeare is apparently not involved in these parallels with Doctor Faustus either as the author of The Taming of the Shrew or as the probable author of the original version of the play.The parallels with A Shrew which are herewith cited seem to call for a theory of a common source in an earlier form of Doctor Faustus than the 1604 and 1616 texts.1

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