scholarly journals Hierarchical Surface Texturing of Hydroxyapatite Ceramics: Influence on the Adhesive Bonding Strength of Polymeric Polycaprolactone

2020 ◽  
Vol 11 (4) ◽  
pp. 73
Author(s):  
Jonas Biggemann ◽  
Philipp Müller ◽  
David Köllner ◽  
Swantje Simon ◽  
Patrizia Hoffmann ◽  
...  
Keyword(s):  
Bonding Strength ◽  
Adhesive Bonding ◽  
Surface Texturing ◽  
Independent Effect ◽  
Nanometer Scale ◽  
Submillimeter Range ◽  
Covalent Bonds ◽  
Hydroxyapatite Ceramics ◽  
Materials Used ◽  
The Individual

The tailored manipulation of ceramic surfaces gained recent interest to optimize the performance and lifetime of composite materials used as implants. In this work, a hierarchical surface texturing of hydroxyapatite (HAp) ceramics was developed to improve the poor adhesive bonding strength in hydroxyapatite and polycaprolactone (HAp/PCL) composites. Four different types of periodic surface morphologies (grooves, cylindric pits, linear waves and Gaussian hills) were realized by a ceramic micro-transfer molding technique in the submillimeter range. A subsequent surface roughening and functionalization on a micron to nanometer scale was obtained by two different etchings with hydrochloric and tartaric acid. An ensuing silane coupling with 3-aminopropyltriethoxysilane (APTES) enhanced the chemical adhesion between the HAp surface and PCL on the nanometer scale by the formation of dipole–dipole interactions and covalent bonds. The adhesive bonding strengths of the individual and combined surface texturings were investigated by performing single-lap compressive shear tests. All individual texturing types (macro, micro and nano) showed significantly improved HAp/PCL interface strengths compared to the non-textured HAp reference, based on an enhanced mechanical, physical and chemical adhesion. The independent effect mechanisms allow the deliberately hierarchical combination of all texturing types without negative influences. The hierarchical surface-textured HAp showed a 6.5 times higher adhesive bonding strength (7.7 ± 1.5 MPa) than the non-textured reference, proving that surface texturing is an attractive method to optimize the component adhesion in composites for potential medical implants.

scholarly journals Cities, the Urban Green Environment, and Individual Subjective Well-Being: The Case of Milan, Italy

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Giorgio Tavano Blessi ◽  
Enzo Grossi ◽  
Giovanni Pieretti ◽  
Guido Ferilli ◽  
Alessandra Landi
Keyword(s):  
Urban Areas ◽  
Well Being ◽  
Spatial Proximity ◽  
Independent Effect ◽  
Subjective Well Being ◽  
Residential Proximity ◽  
Urban Green ◽  
Urban Green Areas ◽  
Green Areas ◽  
The Individual

This paper evaluates the independent effect of the spatial proximity of green urban areas upon the individual subjective well-being of the Milan population (Italy). The methodology is based on a survey undertaken in 2010 using a sample of 1,000 of Milan citizens. Univariate and multivariate analyses and GIS localization have been employed in order to rank the major individual well-being determinants and the relationship between citizens and urban green areas. Results show that the residential proximity of citizens to urban green areas seems to have little bearing on individual subjective well-being.

Vacuum Adhesive Bonding and Stress Isolation for MEMS Resonant Pressure Sensor Package

2011 ◽  
Vol 694 ◽  
pp. 896-900 ◽  
Author(s):  
Yu Xin Li ◽  
De Yong Chen ◽  
Jun Bo Wang
Keyword(s):  
Pressure Sensor ◽  
Bonding Strength ◽  
Adhesive Bonding ◽  
Thermal Stresses ◽  
Time Pressure ◽  
Bonding Temperature ◽  
Bonding Process ◽  
Temperature Drift ◽  
Stress Isolation ◽  
Sensor Package

This paper presents a method of low temperature adhesive bonding and stress isolation for MEMS resonant pressure sensor hermetic packaging using non-photosensitive benzo-cyclo-butene (BCB) from Dow Co. According to the bonding process, pre-bake time, pumping time, pressure placed on the sensor and the thickness of crosslink layer are the most important factors. Stress isolation is designed to minimize thermal stresses to the resonant pressure sensor package. Experimental results show that this bonding process is a viable for MEMS resonant pressure sensor with the bonding temperature below 250°C, measured bonding strength more than 30MPa, the temperature drift less than 0.05%/°C in the range of -40°C to 70°C(10% of that without stress isolation), and the bonding strength maintains well after thermal treatments, handling, bench testing and implantations.

scholarly journals A FULL-SCALE STUDY OF THE STRENGTH OF MASSIVE WOOD GLUING WITH MODERN ADHESIVES WHEN OPERATING IN VARIOUS CONDITIONS

2020 ◽  
Vol 10 (1) ◽  
pp. 105-115
Author(s):  
Larisa Ponomarenko ◽  
Ekaterina Kantieva ◽  
Maksim Posluhaev ◽  
Aleksandr Chernyshev
Keyword(s):  
Bonding Strength ◽  
Polyvinyl Acetate ◽  
Adhesive Bonding ◽  
Adhesive Layer ◽  
Correct Choice ◽  
Operating Conditions ◽  
Furniture Manufacturing ◽  
Wooden House ◽  
House Building ◽  
Adhesive Materials

Abstract Glues are widely used to connect various materials, especially since in some cases other options for combining materials are not suitable. The paper deals with the bonding of solid hardwood with modern adhesive materials. Currently, a large group of adhesives of various brands from Russian and foreign manufacturers is presented on the market. In the woodworking industry, adhesives are used in the carpentry and furniture, manufacturing, in wooden house-building, in the production of finishing materials, etc., which are operated outside and inside the premises in constant and variable humidity conditions. Therefore, the correct choice of adhesives plays an important role both for the manufacturer and subsequently for the consumer of the resulting product. In this work, we have studied the dependence of the tensile strength when chipping along the adhesive layer on the type of glue, wood species, and operating conditions. We have selected the following adhesives based on polychloroprene, polyvinyl acetate and rubber. The greatest strength of the adhesive bonding when gluing solid hardwood is given by polyvinyl acetate adhesives. When using the product in conditions of changing temperature and humidity, the bonding strength decreases, in some cases significantly. In fairness, it should be noted that not only the type of glue, but also the type of wood affects the bonding strength

scholarly journals FEM Analysis of Various Multilayer Structures for CMOS Compatible Wearable Acousto-Optic Devices

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7863
Author(s):  
Mehwish Hanif ◽  
Varun Jeoti ◽  
Mohamad Radzi Ahmad ◽  
Muhammad Zubair Aslam ◽  
Saima Qureshi ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Figure Of Merit ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Fem Analysis ◽  
Film Structure ◽  
Multilayer Structures ◽  
Electromechanical Coupling Coefficient ◽  
Materials Used ◽  
The Individual

Lately, wearable applications featuring photonic on-chip sensors are on the rise. Among many ways of controlling and/or modulating, the acousto-optic technique is seen to be a popular technique. This paper undertakes the study of different multilayer structures that can be fabricated for realizing an acousto-optic device, the objective being to obtain a high acousto-optic figure of merit (AOFM). By varying the thicknesses of the layers of these materials, several properties are discussed. The study shows that the multilayer thin film structure-based devices can give a high value of electromechanical coupling coefficient (k2) and a high AOFM as compared to the bulk piezoelectric/optical materials. The study is conducted to find the optimal normalised thickness of the multilayer structures with a material possessing the best optical and piezoelectric properties for fabricating acousto-optic devices. Based on simulations and studies of SAW propagation characteristics such as the electromechanical coupling coefficient (k2) and phase velocity (v), the acousto-optic figure of merit is calculated. The maximum value of the acousto-optic figure of merit achieved is higher than the AOFM of all the individual materials used in these layer structures. The suggested SAW device has potential application in wearable and small footprint acousto-optic devices and gives better results than those made with bulk piezoelectric materials.

scholarly journals Non-Covalent Interactions Involving Alkaline-Earth Atoms and Lewis Bases B: An ab Initio Investigation of Beryllium and Magnesium Bonds, B···MR2 (M = Be or Mg, and R = H, F or CH3)

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 35 ◽  
Author(s):  
Ibon Alkorta ◽  
Anthony Legon
Keyword(s):  
Ab Initio ◽  
Lewis Acids ◽  
Alkaline Earth ◽  
Basis Set ◽  
Covalent Bonds ◽  
Lewis Bases ◽  
Complete Basis Set ◽  
Definition Of ◽  
The Individual ◽  
Equilibrium Dissociation

Geometries, equilibrium dissociation energies (De), intermolecular stretching, and quadratic force constants (kσ) determined by ab initio calculations conducted at the CCSD(T)/aug-cc-pVTZ level of theory, with De obtained by using the complete basis set (CBS) extrapolation [CCSD(T)/CBS energy], are presented for the B···BeR2 and B···MgR2 complexes, where B is one of the following Lewis bases: CO, H2S, PH3, HCN, H2O or NH3, and R is H, F or CH3. The BeR2 and MgR2 precursor molecules were shown to be linear and non-dipolar. The non-covalent intermolecular bond in the B···BeR2 complexes is shown to result from the interaction of the electrophilic band around the Be atom of BeR2 (as indicated by the molecular electrostatic potential surface) with non-bonding electron pairs of the base, B, and may be described as a beryllium bond by analogy with complexes such as B···CO2, which contain a tetrel bond. The conclusions for the B···MgR2 series are similar and a magnesium bond can be correspondingly invoked. The geometries established for B···BeR2 and B···MgR2 can be rationalized by a simple rule previously enunciated for tetrel-bonded complexes of the type B···CO2. It is also shown that the dissociation energy, De, is directly proportional to the force constant, kσ, in each B···MR2 series, but with a constant of proportionality different from that established for many hydrogen-bonded B···HX complexes and halogen-bonded B···XY complexes. The values of the electrophilicity, EA, determined from the De for B···BeR2 complexes for the individual Lewis acids, A, reveal the order A = BeF2 > BeH2 > Be(CH3)2—a result that is consistent with the −I and +I effects of F and CH3 relative to H. The conclusions for the MgR2 series are similar but, for a given R, they have smaller electrophilicities than those of the BeR2 series. A definition of alkaline-earth non-covalent bonds is presented.

scholarly journals Laser Surface Texturing and Electropolishing of CoCr and Ti6Al4V-ELI Alloys for Biomedical Applications

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5203
Author(s):  
Jesús A. Sandoval-Robles ◽  
Ciro A. Rodríguez ◽  
Erika García-López
Keyword(s):  
Surface Roughness ◽  
Unit Length ◽  
Surface Texturing ◽  
Orthopedic Implants ◽  
Laser Surface Texturing ◽  
Material Surface ◽  
Roughness Parameters ◽  
X Ray ◽  
Surface Roughness Parameters ◽  
Materials Used

The interplay between a prosthetic and tissue represents an important factor for the fixation of orthopedic implants. Laser texturing tests and electropolishing were performed on two materials used in the fabrication of medical devices, i.e., CoCr and Ti6Al4V-ELI alloys. The material surface was textured with a diode-pumped solid state (DPSS) laser and its effect on the surface quality and material modification, under different combinations of laser power and marking speed, were investigated. Our results indicate that an increment of energy per unit length causes an incremental trend in surface roughness parameters. Additionally, phase transformation on the surface of both alloys was achieved. Chemical analysis by energy dispersive X-ray spectrometer (EDX) shows the formation of (Co(Cr,Mo)) phase and the M23C6 precipitate on the CoCr surface; while quantitative analysis of the X-ray diffractometer (XRD) results demonstrates the oxidation of the Ti alloy with the formation of Ti2O and Ti6O from the reduction of the α-Ti phase. The behaviors were both related with an increase of the energy per unit length. Control of the final surface roughness was achieved by an electropolishing post-treatment, minimizing the as-treated values. After polishing, a reduction of surface roughness parameters was obtained in a range between 3% and 44%, while no changes in chemical composition or present phases were observed.

scholarly journals A Low-Cost, Non-hazardous Protocol for Surface Texturing of Glass Particles

2019 ◽  
Vol 67 (4) ◽  
Author(s):  
Anelechi Ibekwe ◽  
Yukie Tanino ◽  
Dubravka Pokrajac
Keyword(s):  
Low Cost ◽  
Packed Column ◽  
Surface Texturing ◽  
Nanometer Scale ◽  
Length Scale ◽  
Glass Spheres ◽  
Hard Particles ◽  
Microscope Images ◽  
Scanning Electron ◽  
Roughness Size

Abstract We present a cheap, efficient, and non-hazardous protocol for altering the roughness of hard particles at the nanometer-scale using a stone tumbler, a tool which is normally used for polishing stones. Six different textures were achieved by lining the tumbler with sandpaper of mean grit diameters $$d_{\mathrm{g}}=201$$dg=201, 58.5, 18.3, 12.6, and $$8.4\,\upmu \hbox {m}$$8.4μm. Two textures were created by tumbling a batch of glass spheres for 4 h and for 12 h with the $$12.6\,\upmu \hbox {m}$$12.6μm sandpaper; all other textures were established by tumbling for 12 h. Surface roughness was characterized by the integral length scale, $$\xi$$ξ, evaluated from 7 nm/pix resolution scanning electron microscope images. Roughness size increased from $$\xi = 24$$ξ=24 to 31 nm as the grit size decreased from $$d_{\mathrm{g}} = 201$$dg=201 to $$18.3\,\upmu \hbox {m}$$18.3μm, and then decreased to $$\xi = 6.4\,\hbox {nm}$$ξ=6.4nm at the smallest $$d_{\mathrm{g}}$$dg. The largest $$\xi \,(= 34\,\hbox {nm})$$ξ(=34nm) was achieved using a $$12.6\,\upmu \hbox {m}$$12.6μm sandpaper and the shorter tumbling time of 4 h. The permeability of a packed column of the particles broadly decreased with increasing $$\xi$$ξ, indicating that permeability decreases with increasing roughness size.

Nanometer-scale features on micrometer-scale surface texturing: A bone histological, gene expression, and nanomechanical study

Bone ◽  
2014 ◽  
Vol 65 ◽  
pp. 25-32 ◽  
Author(s):  
Paulo G. Coelho ◽  
Tadahiro Takayama ◽  
Daniel Yoo ◽  
Ryo Jimbo ◽  
Sanjay Karunagaran ◽  
...  
Keyword(s):  
Gene Expression ◽  
Surface Texturing ◽  
Nanometer Scale ◽  
Micrometer Scale ◽  
Scale Surface

Damascene-Patterned Metal-Adhesive (Cu-BCB) Redistribution Layers

2006 ◽  
Vol 970 ◽  
Author(s):  
Ronald J. Gutmann ◽  
J. Jay McMahon ◽  
Jian-Qiang Lu
Keyword(s):  
Bonding Strength ◽  
Adhesive Bonding ◽  
Process Integration ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Wafer Level ◽  
Technology Platform ◽  
Metal Bonding ◽  
Wafer Level Packaging ◽  
Metal Metal

ABSTRACTA monolithic, wafer-level three-dimensional (3D) technology platform is described that is compatible with next-generation wafer level packaging (WLP) processes. The platform combines the advantages of both (1) high bonding strength and adaptability to IC wafer topography variations with spin-on dielectric adhesive bonding and (2) process integration and via-area advantages of metal-metal bonding. A copper-benzocyclobutene (Cu-BCB) process is described that incorporates single-level damascene-patterned Cu vias with partially-cured BCB as the bonding adhesive layer. A demonstration vehicle consisting of a two-wafer stack of 2-4 μm diameter vias has shown the bondability of both Cu-to-Cu and BCB-to-BCB. Planarization conditions to achieve BCB-BCB bonding with low-resistance Cu-Cu contacts have been examined, with wafer-scale planarization requirements compared to other 3D platforms. Concerns about stress induced at the tantalum (Ta) liner-to-BCB interface resulting in partial delamination are discussed. While across-wafer uniformity has not been demonstrated, the viability of this WLP-compatible 3D platform has been shown.

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