Materials

Research

19 pages, 648 KiB

Open AccessArticle

Bone Tissue Engineering with Adipose-Derived Stem Cells in Bioactive Composites of Laser-Sintered Porous Polycaprolactone Scaffolds and Platelet-Rich Plasma

by Han-Tsung Liao^1,2, Jyh-Ping Chen^1,3,*

and Ming-Yih Lee⁴

¹ Department of Chemical and Materials Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan

² Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Craniofacial Research Center, College of Medicine, Chang Gung University, Kweishan, Taoyuan 333, Taiwan

³ Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Kweishan, Taoyuan 333, Taiwan

⁴ Department of Mechanical Engineering, Chang Gung University, Kweishan, Taoyuan 333, Taiwan

Materials 2013, 6(11), 4911-4929; https://doi.org/10.3390/ma6114911 - 25 Oct 2013

Cited by 18 | Viewed by 6785

Abstract

Three-dimensional porous polycaprolactone (PCL) scaffolds with consistent inter-pore channels, 83% porosity and 300–400 μm pore size were fabricated via selective laser sintering. The PCL scaffold was combined with platelet-rich plasma (PRP) to form a bioactive composite and studied for potential application in bone [...] Read more.

Three-dimensional porous polycaprolactone (PCL) scaffolds with consistent inter-pore channels, 83% porosity and 300–400 μm pore size were fabricated via selective laser sintering. The PCL scaffold was combined with platelet-rich plasma (PRP) to form a bioactive composite and studied for potential application in bone tissue engineering using porcine adipose-derived stem cells (PASCs). The PCL/PRP/PASCs construct showed enhanced cell seeding efficiency and synergistically increased the differentiation capability of PASCs in osteogenic medium toward the osteoblast lineage, judging from elevated alkaline phosphatase activity and up-regulated osteogenic genes expression. For in vivo study, a 3 cm × 3 cm mandible defect was created in pigs and reconstructed by implanting acellular PCL scaffolds or PCL/PRP/PASCs constructs. Both groups showed new bone formation, however, the new bone volume was 5.1 times higher for PCL/PRP/PASCs 6 months post-operation. The bone density was less and loose in the acellular PCL group and the Young’s modulus was only 29% of normal bone. In contrast, continued and compact bone formation was found in PCL/PRP/PASCs and the Young’s modulus was 81% that of normal bone. Masson’s trichrome stain, immunohistochemical analysis of osteocalcin and collagen type I also confirmed new bone formation. Full article

(This article belongs to the Section Biomaterials)

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16 pages, 2815 KiB

Open AccessArticle

Novel Ti–Zr–Hf–Fe Nanostructured Alloy for Biomedical Applications

by Anna Hynowska^1,*, Andreu Blanquer²

, Eva Pellicer^1,*

, Jordina Fornell¹, Santiago Suriñach¹

, Maria Dolors Baró¹, Sergio González¹, Elena Ibáñez², Lleonard Barrios²

, Carme Nogués^2,*

and Jordi Sort³

¹ Departament de Física, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain

² Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain

³ Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain

Materials 2013, 6(11), 4930-4945; https://doi.org/10.3390/ma6114930 - 25 Oct 2013

Cited by 35 | Viewed by 6889

Abstract

The synthesis and characterization of Ti₄₀Zr₂₀Hf₂₀Fe₂₀ (atom %) alloy, in the form of rods (f = 2 mm), prepared by arc-melting, and subsequent Cu mold suction casting, is presented. The microstructure, mechanical and corrosion properties, as [...] Read more.

The synthesis and characterization of Ti₄₀Zr₂₀Hf₂₀Fe₂₀ (atom %) alloy, in the form of rods (f = 2 mm), prepared by arc-melting, and subsequent Cu mold suction casting, is presented. The microstructure, mechanical and corrosion properties, as well as in vitro biocompatibility of this alloy, are investigated. This material consists of a mixture of several nanocrystalline phases. It exhibits excellent mechanical behavior, dominated by high strength and relatively low Young’s modulus, and also good corrosion resistance, as evidenced by the passive behavior in a wide potential window and the low corrosion current densities values. In terms of biocompatibility, this alloy is not cytotoxic and preosteoblast cells can easily adhere onto its surface and differentiate into osteoblasts. Full article

(This article belongs to the Special Issue Titanium Materials for Biomedical Application 2013)

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21 pages, 1102 KiB

Open AccessArticle

Influence of a Thiolate Chemical Layer on GaAs (100) Biofunctionalization: An Original Approach Coupling Atomic Force Microscopy and Mass Spectrometry Methods

by Alex Bienaime¹, Therese Leblois¹, Nicolas Gremaud¹, Maxime-Jean Chaudon¹, Marven El Osta², Delphine Pecqueur², Patrick Ducoroy² and Celine Elie-Caille^1,*

¹ MicroNanoSciences and Systems Department, Franche-Comté Electronique, Mécanique, Thermique et Optique—Sciences et Technologies (FEMTO-ST) Institute, 32 avenue de l'Observatoire, 25044 Besançon Cedex, France

² Clinical and Innovation Proteomic Platform, University of Burgundy, CHU, 21000 Dijon, France

Materials 2013, 6(11), 4946-4966; https://doi.org/10.3390/ma6114946 - 25 Oct 2013

Cited by 8 | Viewed by 5837

Abstract

Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs) is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly [...] Read more.

Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs) is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly sensitive transducer with a specific bio-interface; which are the two essential parts of a biosensor. To optimize the biorecognition part; it is necessary to control protein coverage and the binding affinity of the protein layer on the GaAs surface. In this paper; we investigate the potential of a specific chemical interface composed of thiolate molecules with different chain lengths; possessing hydroxyl (MUDO; for 11-mercapto-1-undecanol (HS(CH₂)₁₁OH)) or carboxyl (MHDA; for mercaptohexadecanoic acid (HS(CH₂)₁₅CO₂H)) end groups; to reconstitute a dense and homogeneous albumin (Rat Serum Albumin; RSA) protein layer on the GaAs (100) surface. The protein monolayer formation and the covalent binding existing between RSA proteins and carboxyl end groups were characterized by atomic force microscopy (AFM) analysis. Characterization in terms of topography; protein layer thickness and stability lead us to propose the 10% MHDA/MUDO interface as the optimal chemical layer to efficiently graft proteins. This analysis was coupled with in situ MALDI-TOF mass spectrometry measurements; which proved the presence of a dense and uniform grafted protein layer on the 10% MHDA/MUDO interface. We show in this study that a critical number of carboxylic docking sites (10%) is required to obtain homogeneous and dense protein coverage on GaAs. Such a protein bio-interface is of fundamental importance to ensure a highly specific and sensitive biosensor. Full article

(This article belongs to the Special Issue Functional Materials and Proteins for Bio-Sensing Applications)

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18 pages, 1018 KiB

Open AccessArticle

Predicting the Coupling Properties of Axially-Textured Materials

by Luis E. Fuentes-Cobas^1,*

, Alejandro Muñoz-Romero², María E. Montero-Cabrera¹

, Luis Fuentes-Montero³ and María E. Fuentes-Montero⁴

¹ Centro de Investigación en Materiales Avanzados, Miguel de Cervantes 120, Chihuahua, Chih 31109, Mexico

² Delphi Automotive Systems, The Mexico Technical Center, Av Hermanos Escobar No 5756, Ciudad Juarez, Chih 32310, Mexico

³ Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK

⁴ Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Nuevo Campus Universitario, Circuito Universitario Chihuahua, Chih 31125, Mexico

Materials 2013, 6(11), 4967-4984; https://doi.org/10.3390/ma6114967 - 30 Oct 2013

Cited by 15 | Viewed by 5386

Abstract

A description of methods and computer programs for the prediction of “coupling properties” in axially-textured polycrystals is presented. Starting data are the single-crystal properties, texture and stereography. The validity and proper protocols for applying the Voigt, Reuss and Hill approximations to estimate coupling [...] Read more.

A description of methods and computer programs for the prediction of “coupling properties” in axially-textured polycrystals is presented. Starting data are the single-crystal properties, texture and stereography. The validity and proper protocols for applying the Voigt, Reuss and Hill approximations to estimate coupling properties effective values is analyzed. Working algorithms for predicting mentioned averages are given. Bunge’s symmetrized spherical harmonics expansion of orientation distribution functions, inverse pole figures and (single and polycrystals) physical properties is applied in all stages of the proposed methodology. The established mathematical route has been systematized in a working computer program. The discussion of piezoelectricity in a representative textured ferro-piezoelectric ceramic illustrates the application of the proposed methodology. Polycrystal coupling properties, predicted by the suggested route, are fairly close to experimentally measured ones. Full article

(This article belongs to the Section Advanced Materials Characterization)

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Graphical abstract

15 pages, 863 KiB

Open AccessArticle

The Effect of Stretching on Ultraviolet Protection of Cotton and Cotton/Coolmax-Blended Weft Knitted Fabric in a Dry State

by Chi-wai Kan^1,*, Lim-yung Yam¹ and Sun-pui Ng²

¹ Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 852, China

² Hong Kong Community College, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 852, China

Materials 2013, 6(11), 4985-4999; https://doi.org/10.3390/ma6114985 - 31 Oct 2013

Cited by 19 | Viewed by 6491

Abstract

In this paper, the ultraviolet protection factor (UPF) of weft knitted fabrics made from 20Ne cotton yarn, Coolmax yarn and their blends in dry, relaxed and stretched states were studied. According to the fibre composition, samples were divided into three groups: Group I [...] Read more.

In this paper, the ultraviolet protection factor (UPF) of weft knitted fabrics made from 20Ne cotton yarn, Coolmax yarn and their blends in dry, relaxed and stretched states were studied. According to the fibre composition, samples were divided into three groups: Group I (single cotton yarn); Group II (cotton/cotton combination); and Group III (Coolmax/cotton combination) for discussion. In addition, yarn and fabric properties such as yarn tenacity, yarn strength, fibre combination and water vapour transmission that affect the corresponding UPF values are used for formulating a prediction model in order to determine UPF. Generally speaking, when samples are measured under stretched conditions in a dry state, they exhibit a remarkable reduction in ultraviolet protective power, as pores are opened up and UV radiation can easily penetrate through these pores. In addition, greater stretch percentage came along with greater reduction in UPF. This can be explained by the fact that the amount and the size of pores increase when samples are subjected to greater tension. Full article

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16 pages, 1133 KiB

Open AccessArticle

Coal Combustion Wastes Reuse in Low Energy Artificial Aggregates Manufacturing

by Claudio Ferone^1,*

, Francesco Colangelo¹

, Francesco Messina¹, Fabio Iucolano², Barbara Liguori²

and Raffaele Cioffi¹

¹ INSTM Research Group Naples Parthenope, Department of Engineering, Parthenope University of Naples, Centro Direzionale Naples, Isola C4, Naples 80143, Italy

² Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio, 80, Naples 80125, Italy

Materials 2013, 6(11), 5000-5015; https://doi.org/10.3390/ma6115000 - 31 Oct 2013

Cited by 72 | Viewed by 7312

Abstract

Sustainable building material design relies mostly on energy saving processes, decrease of raw materials consumption, and increase of waste and by-products recycling. Natural and lightweight artificial aggregates production implies relevant environmental impact. This paper addresses both the issues of residues recycling and energy [...] Read more.

Sustainable building material design relies mostly on energy saving processes, decrease of raw materials consumption, and increase of waste and by-products recycling. Natural and lightweight artificial aggregates production implies relevant environmental impact. This paper addresses both the issues of residues recycling and energy optimization. Particularly, three coal combustion wastes (Weathered Fly Ash, WFA; Wastewater Treatment Sludge, WTS; Desulfurization Device Sludge, DDS) supplied by the Italian electric utility company (ENEL) have been employed in the manufacture of cold bonded artificial aggregates. Previously, the residues have been characterized in terms of chemical and mineralogical compositions, water content, particle size distribution, and heavy metal release behavior. These wastes have been used in the mix design of binding systems with the only addition of lime. Finally, the artificial aggregates have been submitted to physical, mechanical, and leaching testing, revealing that they are potentially suitable for many civil engineering applications. Full article

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22 pages, 3147 KiB

Open AccessArticle

Microstructure of Haynes^® 282^® Superalloy after Vacuum Induction Melting and Investment Casting of Thin-Walled Components

by Hubert Matysiak^1,*, Malgorzata Zagorska², Joel Andersson^3,4,5, Alicja Balkowiec², Rafal Cygan⁶, Marcin Rasinski², Marcin Pisarek⁷, Mariusz Andrzejczuk², Krzysztof Kubiak⁸ and Krzysztof J. Kurzydlowski²

¹ Functional Materials Research Center, Warsaw University of Technology, Woloska 141, Warsaw 02-507, Poland

² Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, Warsaw 02-507, Poland

³ Guest, Keen and Nettlefolds (GKN) Aerospace Engine Systems Sweden, Trollhättan S-46181, Sweden

⁴ Department of Engineering Science, University West, Trollhättan 46186, Sweden

⁵ Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg 41296, Sweden

⁶ Wytwornia Sprzetu Komunikacyjnego, "Polskie Zaklady Lotnicze Rzeszow" S.A., Hetmanska 120, Rzeszow 35-078, Poland

⁷ Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland

⁸ Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Al. Powstancow Warszawy 8, Rzeszow 35-959, Poland

Materials 2013, 6(11), 5016-5037; https://doi.org/10.3390/ma6115016 - 1 Nov 2013

Cited by 55 | Viewed by 11047

Abstract

The aim of this work was to characterize the microstructure of the as-cast Haynes^® 282^® alloy. Observations and analyses were carried out using techniques such as X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray [...] Read more.

The aim of this work was to characterize the microstructure of the as-cast Haynes^® 282^® alloy. Observations and analyses were carried out using techniques such as X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray spectroscopy (EDS), wave length dispersive X-ray spectroscopy (WDS), auger electron spectroscopy (AES) and electron energy-loss spectrometry (EELS). The phases identified in the as-cast alloy include: γ (gamma matrix), γʹ (matrix strengthening phase), (TiMoCr)C (primary carbide), TiN (primary nitride), σ (sigma-TCP phase), (TiMo)₂SC (carbosulphide) and a lamellar constituent consisting of molybdenum and chromium rich secondary carbide phase together with γ phase. Within the dendrites the γʹ appears mostly in the form of spherical, nanometric precipitates (74 nm), while coarser (113 nm) cubic γʹ precipitates are present in the interdendritic areas. Volume fraction content of the γʹ precipitates in the dendrites and interdendritic areas are 9.6% and 8.5%, respectively. Primary nitrides metallic nitrides (MN), are homogeneously dispersed in the as-cast microstructure, while primary carbides metallic carbides (MC), preferentially precipitate in interdendritic areas. Such preference is also observed in the case of globular σ phase. Lamellar constituents characterized as secondary carbides/γ phases were together with (TiMo)₂SC phase always observed adjacent to σ phase precipitates. Crystallographic relations were established in-between the MC, σ, secondary carbides and γ/γʹ matrix. Full article

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9 pages, 390 KiB

Open AccessArticle

A Sensitive DNAzyme-Based Chiral Sensor for Lead Detection

by Hua Kuang^*, Honghong Yin, Changrui Xing and Chuanlai Xu

State Key Lab of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China

Materials 2013, 6(11), 5038-5046; https://doi.org/10.3390/ma6115038 - 1 Nov 2013

Cited by 18 | Viewed by 6260

Abstract

A DNAzyme-based sensor for the determination and quantification of lead ions (Pb²⁺) has been established, which combines the recognition and catalysis of DNAzyme with the optical properties of nanomaterials. Circular dichroism (CD) signals were obtained by a DNAzyme-based assembly of asymmetric [...] Read more.

A DNAzyme-based sensor for the determination and quantification of lead ions (Pb²⁺) has been established, which combines the recognition and catalysis of DNAzyme with the optical properties of nanomaterials. Circular dichroism (CD) signals were obtained by a DNAzyme-based assembly of asymmetric silver nanoparticle (AgNPs) dimers. A good linear relationship between CD signals and Pb²⁺concentration was obtained ranging from 0.05 ng∙mL⁻¹ to 10 ng∙mL⁻¹ with a limit of detection (LOD) of 0.02 ng∙mL⁻¹. The specificity of this sensor in lead ion detection was excellent, and a satisfactory recovery was obtained in the analysis of tap water samples. The proposed technique possesses both high sensitivity and good specificity, giving it great potential for the analysis of Pb²⁺ in water. Full article

(This article belongs to the Special Issue Functional Materials and Proteins for Bio-Sensing Applications)

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11 pages, 1028 KiB

Open AccessArticle

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

by Mastura Shafinaz Zainal Abidin^1,*, Ryo Matsumura², Mohammad Anisuzzaman², Jong-Hyeok Park², Shunpei Muta², Mohamad Rusop Mahmood³, Taizoh Sadoh² and Abdul Manaf Hashim^4,5

¹ Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor, Skudai 81310, Malaysia

² Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan

³ Faculty of Electrical Engineering, Universiti Teknologi MARA, Selangor, Shah Alam 40450, Malaysia

⁴ Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Semarak, Kuala Lumpur 54100, Malaysia

⁵ MIMOS Berhad, Technology Park Malaysia, Kuala Lumpur 57000, Malaysia

Materials 2013, 6(11), 5047-5057; https://doi.org/10.3390/ma6115047 - 6 Nov 2013

Cited by 13 | Viewed by 6690

Abstract

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of [...] Read more.

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm⁻¹ corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm⁻¹ corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility. Full article

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11 pages, 3527 KiB

Open AccessArticle

A Near-Zero Refractive Index Meta-Surface Structure for Antenna Performance Improvement

by Mohammad Habib Ullah^1,2, Mohammad Tariqul Islam^1,* and Mohammad Rashed Iqbal Faruque¹

¹ Institute of Space Science (ANGKASA), National University Malaysia, Bangi, Selangor 43600, Malaysia

² Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, National University Malaysia, Bangi, Selangor 43600, Malaysia

Materials 2013, 6(11), 5058-5068; https://doi.org/10.3390/ma6115058 - 6 Nov 2013

Cited by 48 | Viewed by 8020

Abstract

A new meta-surface structure (MSS) with a near-zero refractive index (NZRI) is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating [...] Read more.

A new meta-surface structure (MSS) with a near-zero refractive index (NZRI) is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating the planar NZRI MSS at the back of the antenna structure. The proposed NZRI MSS-loaded CPW-fed (Co-Planar Waveguide) four-element array antenna is designed on ceramic-bioplastic-ceramic sandwich substrate using high-frequency structure simulator (HFSS), a finite-element-method-based simulation tool. The gain and directivity of the antenna are significantly enhanced by incorporating the NZRI MSS with a 7 × 6 set of elements at the back of the antenna structure. Measurement results show that the maximum gains of the antenna increased from 6.21 dBi to 8.25 dBi, from 6.52 dBi to 9.05 dBi and from 10.54 dBi to 12.15 dBi in the first, second and third bands, respectively. The effect of the slot configuration in the ground plane on the reflection coefficient of the antenna was analyzed and optimized. The overall performance makes the proposed antenna appropriate for UHFFM (Ultra High Frequency Frequency Modulation) telemetry-based space applications as well as mobile satellite, microwave radiometry and radio astronomy applications. Full article

(This article belongs to the Section Advanced Materials Characterization)

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8 pages, 279 KiB

Open AccessArticle

Influence of Curing on the Strength Development of Calcium-Containing Geopolymer Mortar

by Xueying Li^*, Zheng Wang and Zhenzhen Jiao^*

School of Civil Engineering, Harbin Institute of Technology, Harbin 150006, China

Materials 2013, 6(11), 5069-5076; https://doi.org/10.3390/ma6115069 - 7 Nov 2013

Cited by 81 | Viewed by 6553

Abstract

This paper investigated the curing effects on the mechanical properties of calcium-containing geopolymer mortar. Three precursors are used: Class C fly ash, Class F fly ash plus calcium hydroxide and Class F fly ash plus slag. Curing conditions included: (1) standard curing at [...] Read more.

This paper investigated the curing effects on the mechanical properties of calcium-containing geopolymer mortar. Three precursors are used: Class C fly ash, Class F fly ash plus calcium hydroxide and Class F fly ash plus slag. Curing conditions included: (1) standard curing at 20 ± 3 °C and RH 95% (C); (2) steam curing at 60 °C for 24 h (S); (3) steam curing at 60 °C for 6 h (S6); and (4) oven curing at 60 °C for 24 h (O), then the latter three followed by the standard curing. Under the standard conditions, the flexural strength and compressive strength of Class C fly ash geopolymer mortars developed quickly until the age of 7 days, followed by a gradual increase. Specimens with Class F fly ash plus Ca(OH)₂ showed slow increase till the age of 28 days. Under these non-standard conditions (2–4), all specimens showed higher 3-day strength, while later strengths were either higher or lower than those in standard conditions, depending on the type of the precursor. Full article

(This article belongs to the Section Advanced Composites)

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17 pages, 780 KiB

Open AccessArticle

Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO

by Wei-Cheng Chu, Shih-Fan Chiang, Jheng-Guang Li and Shiao-Wei Kuo^*

Center for Nanoscience and Nanotechnology, Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan

Materials 2013, 6(11), 5077-5093; https://doi.org/10.3390/ma6115077 - 7 Nov 2013

Cited by 24 | Viewed by 8873

Abstract

After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-b-PPO-b-PEO) with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH [...] Read more.

After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-b-PPO-b-PEO) with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation. Mild pyrolysis conditions led to the removal of the PEO-b-PPO-b-PEO triblock copolymer and formation of mesoporous phenolic resin. This approach provided a variety of composition-dependent nanostructures, including disordered wormlike, body-centered-cubic spherical and disorder micelles. The regular mesoporous novolac-type phenolic resin was formed only at a phenolic content of 40–60 wt %, the result of an intriguing balance of hydrogen bonding interactions among the phenolic resin and the PEO and PPO segments of the triblock copolymer. Full article

(This article belongs to the Special Issue Advances in Nanoporous Materials)

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13 pages, 790 KiB

Open AccessArticle

Investigation on the Residual Stress State of Drawn Tubes by Numerical Simulation and Neutron Diffraction Analysis

by Heinz Palkowski^1,*, Sebastian Brück², Thilo Pirling³ and Adele Carradò⁴

¹ Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, Clausthal-Zellerfeld 38678, Germany

² Eberspächer GmbH & Co. KG, Hamburger Str. 95, Neunkirchen 66539, Germany

³ Institut Laue-Langevin, 6 rue Jules Horowitz, Grenoble 38000, France

⁴ Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 UDS-CNRS, 23 rue du Loess, BP 43, Strasbourg cedex 2 67034, France

Materials 2013, 6(11), 5118-5130; https://doi.org/10.3390/ma6115118 - 8 Nov 2013

Cited by 31 | Viewed by 7591

Abstract

Cold drawing is widely applied in the industrial production of seamless tubes, employed for various mechanical applications. During pre-processing, deviations in tools and their adjustment lead to inhomogeneities in the geometry of the tubes and cause a gradient in residuals. In this paper [...] Read more.

Cold drawing is widely applied in the industrial production of seamless tubes, employed for various mechanical applications. During pre-processing, deviations in tools and their adjustment lead to inhomogeneities in the geometry of the tubes and cause a gradient in residuals. In this paper a three dimensional finite element (3D-FE)-model is presented which was developed to calculate the change in wall thickness, eccentricity, ovality and residual macro-stress state of the tubes, produced by cold drawing. The model simulates the drawing process of tubes, drawn with and without a plug. For finite element modelling, the commercial software package Abaqus was used. To validate the model, neutron strain imaging measurements were performed on the strain imaging instrument SALSA at the Institute Laue Langevin (ILL, Grenoble, France) on a series of SF-copper tubes, drawn under controlled laboratory conditions, varying the drawing angle and the plug geometry. It can be stated that there is sufficient agreement between the finite element method (FEM)-calculation and the neutron stress determination. Full article

(This article belongs to the Section Advanced Materials Characterization)

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12 pages, 740 KiB

Open AccessArticle

A Two-Dimensional Modeling Procedure to Estimate the Loss Equivalent Resistance Including the Saturation Effect

by Rosa Ana Salas

Electronic Technology Department, Higher Polytechnic School, Carlos III University of Madrid, Avda. de la Universidad, 30, 28911, Leganés (Madrid), Spain

Materials 2013, 6(11), 5159-5170; https://doi.org/10.3390/ma6115159 - 12 Nov 2013

Cited by 1 | Viewed by 4972

Abstract

We propose a modeling procedure specifically designed for a ferrite inductor excited by a waveform in time domain. We estimate the loss resistance in the core (parameter of the electrical model of the inductor) by means of a Finite Element Method in 2D [...] Read more.

We propose a modeling procedure specifically designed for a ferrite inductor excited by a waveform in time domain. We estimate the loss resistance in the core (parameter of the electrical model of the inductor) by means of a Finite Element Method in 2D which leads to significant computational advantages over the 3D model. The methodology is validated for an RM (rectangular modulus) ferrite core working in the linear and the saturation regions. Excellent agreement is found between the experimental data and the computational results. Full article

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18 pages, 1054 KiB

Open AccessArticle

Preparation and Characterization of Guar-Montmorillonite Nanocomposites

by Rola Mansa and Christian Detellier^*

Centre for Catalysis Research and Innovation and Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada

Materials 2013, 6(11), 5199-5216; https://doi.org/10.3390/ma6115199 - 13 Nov 2013

Cited by 40 | Viewed by 7842

Abstract

Polymer-clay nanocomposites are highly sought-after materials, mainly due to their applicability in a variety of avenues. From the standpoint of the preparation of these nanocomposites, however, organic compatibility with clay and adherence to “green chemistry” concepts and principles can be limiting factors. As [...] Read more.

Polymer-clay nanocomposites are highly sought-after materials, mainly due to their applicability in a variety of avenues. From the standpoint of the preparation of these nanocomposites, however, organic compatibility with clay and adherence to “green chemistry” concepts and principles can be limiting factors. As such, the objective was to prepare a biopolymer-modified clay nanocomposite using a simple and environmentally friendly method of preparation, whereby pre-treatment of the clay for organic compatibility was bypassed. Novel montmorillonite nanocomposites were prepared using neutral guar gum and cationic guar gum. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of intercalated structures. A monolayer configuration of cationic guar within the interlayer space was indicated by XRD results, while treatment with neutral guar gum resulted in the observance of both monolayer and bilayer configurations. Additionally, TEM results indicated partial exfoliation. Results attributed from ¹³C cross polarization/magic angle spinning nuclear magnetic resonance spectroscopy (CP/MAS NMR) of the nanocomposites indicated peaks corresponding to the guar constituent, confirming the adsorption of the biopolymer. Inductively coupled plasma emission spectrometry (ICP-ES) results indicated the exchange of cations present in neutral guar gum with the sodium cations of montmorillonite, in the case of the neutral guar nanocomposites. Full article

(This article belongs to the Special Issue Nanocomposites of Polymers and Inorganic Particles 2013)

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17 pages, 1082 KiB

Open AccessArticle

Impact of Intragranular Substructure Parameters on the Forming Limit Diagrams of Single-Phase B.C.C. Steels

by Gérald Franz¹, Farid Abed-Meraim^2,3,*

and Marcel Berveiller²

¹ Laboratoire des Technologies Innovantes (LTI), EA 3899—IUT Amiens, Avenue des Facultés—Le Bailly, Amiens Cedex 1 F-80025, France

² Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR CNRS 7239—Arts et Métiers ParisTech, 4 rue Augustin Fresnel, Metz Cedex 3 F-57078, France

³ Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), University of Lorraine, Ile du Saulcy, Metz Cedex 1 F-57045, France

Materials 2013, 6(11), 5217-5233; https://doi.org/10.3390/ma6115217 - 13 Nov 2013

Cited by 1 | Viewed by 5559

Abstract

An advanced elastic-plastic self-consistent polycrystalline model, accounting for intragranular microstructure development and evolution, is coupled with a bifurcation-based localization criterion and applied to the numerical investigation of the impact of microstructural patterns on ductility of single-phase steels. The proposed multiscale model, taking into [...] Read more.

An advanced elastic-plastic self-consistent polycrystalline model, accounting for intragranular microstructure development and evolution, is coupled with a bifurcation-based localization criterion and applied to the numerical investigation of the impact of microstructural patterns on ductility of single-phase steels. The proposed multiscale model, taking into account essential microstructural aspects, such as initial and induced textures, dislocation densities, and softening mechanisms, allows us to emphasize the relationship between intragranular microstructure of B.C.C. steels and their ductility. A qualitative study in terms of forming limit diagrams for various dislocation networks, during monotonic loading tests, is conducted in order to analyze the impact of intragranular substructure parameters on the formability of single-phase B.C.C. steels. Full article

(This article belongs to the Special Issue Computational Modeling and Simulation in Materials Study)

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13 pages, 1692 KiB

Open AccessArticle

Preparation of “Cauliflower-Like” ZnO Micron-Sized Particles

by Tamar Gordon, Judith Grinblat and Shlomo Margel^*

Department of Chemistry, The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 52900, Israel

Materials 2013, 6(11), 5234-5246; https://doi.org/10.3390/ma6115234 - 14 Nov 2013

Cited by 7 | Viewed by 7001

Abstract

Porous polydivinyl benzene (PDVB) microspheres of narrow size distribution were formed by a single-step swelling process of template uniform polystyrene microspheres with divinyl benzene (DVB), followed by polymerization of the DVB within the swollen template microspheres. The PDVB porous particles were then formed [...] Read more.

Porous polydivinyl benzene (PDVB) microspheres of narrow size distribution were formed by a single-step swelling process of template uniform polystyrene microspheres with divinyl benzene (DVB), followed by polymerization of the DVB within the swollen template microspheres. The PDVB porous particles were then formed by dissolution of the template polystyrene polymer. Unique “cauliflower-like” ZnO microparticles were prepared by the entrapping of the ZnO precursor ZnCl₂ in the PDVB porous microspheres under vacuum, followed by calcination of the obtained ZnCl₂-PDVB microspheres in an air atmosphere. The morphology, crystallinity and fluorescence properties of those ZnO microparticles were characterized. This “cauliflower-like” shape ZnO particles is in contrast to a previous study demonstrated the preparation of spherical shaped porous ZnO and C-ZnO microparticles by a similar method, using zinc acetate (ZnAc) as a precursor. Two diverted synthesis mechanisms for those two different ZnO microparticles structures are proposed, based on studies of the distribution of each of the ZnO precursors within the PDVB microspheres. Full article

(This article belongs to the Special Issue Nanocomposites of Polymers and Inorganic Particles 2013)

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Graphical abstract

11 pages, 503 KiB

Open AccessCommunication

Magnetic Phase Transition in Ion-Irradiated Ultrathin CoN Films via Magneto-Optic Faraday Effect

by Chiung-Wu Su^*, Yen-Chu Chang and Sheng-Chi Chang

Department of Electrophysics, National Chiayi University, 300 Syuefu Rd., Chiayi 60004, Taiwan

Materials 2013, 6(11), 5247-5257; https://doi.org/10.3390/ma6115247 - 15 Nov 2013

Cited by 4 | Viewed by 5852

Abstract

The magnetic properties of 1 nm thick in-plane anisotropic Co ultrathin film on ZnO(0001) were investigated through successive 500 eV nitrogen-ion sputtering. Magneto-optical Faraday effects were used to observe the evolution of the ion-irradiated sample in longitudinal and perpendicular magnetic fields. The ferromagnetic [...] Read more.

The magnetic properties of 1 nm thick in-plane anisotropic Co ultrathin film on ZnO(0001) were investigated through successive 500 eV nitrogen-ion sputtering. Magneto-optical Faraday effects were used to observe the evolution of the ion-irradiated sample in longitudinal and perpendicular magnetic fields. The ferromagnetic phase of the initial in-plane anisotropic fcc β-Co phase transformation to β-Co(N) phase was terminated at paramagnetic CoN_x phase. In-plane anisotropy with weak out-of-plane anisotropy of the Co/ZnO sample was initially observed in the as-grown condition. In the sputtering process, the N⁺ ions induced simultaneous sputtering and doping. An abrupt spin reorientation behavior from in-plane to out-of-plane was found under prolonged sputtering condition. The existence of perpendicular anisotropy measured from the out-of-plane Faraday effect may be attributed to the co-existence of residual β-Co and Co₄N exchange bonding force by the gradual depletion of Co-N thickness. Full article

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17 pages, 1317 KiB

Open AccessArticle

Titanium Corrosion Mechanisms in the Oral Environment: A Retrieval Study

by Danieli C. Rodrigues^1,*, Pilar Valderrama², Thomas G. Wilson, Jr.³, Kelli Palmer⁴, Anie Thomas¹, Sathyanarayanan Sridhar¹, Arvind Adapalli¹, Maria Burbano¹ and Chandur Wadhwani⁵

¹ Department of Bioengineering, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX 75080, USA

² Department of Periodontics, Texas A&M University Baylor College of Dentistry, 3302 Gaston Av, Dallas, TX 75246, USA

³ Private Practice of Periodontics, 5465 Blair Road suite 200, Dallas, TX 75231, USA

⁴ Department of Molecular and Cell Biology, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX 75080, USA

⁵ Department of Restorative Dentistry, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA

Materials 2013, 6(11), 5258-5274; https://doi.org/10.3390/ma6115258 - 15 Nov 2013

Cited by 180 | Viewed by 15296

Abstract

Corrosion of titanium dental implants has been associated with implant failure and is considered one of the triggering factors for peri-implantitis. This corrosion is concerning, because a large amount of metal ions and debris are generated in this process, the accumulation of which [...] Read more.

Corrosion of titanium dental implants has been associated with implant failure and is considered one of the triggering factors for peri-implantitis. This corrosion is concerning, because a large amount of metal ions and debris are generated in this process, the accumulation of which may lead to adverse tissue reactions in vivo. The goal of this study is to investigate the mechanisms for implant degradation by evaluating the surface of five titanium dental implants retrieved due to peri-implantitis. The results demonstrated that all the implants were subjected to very acidic environments, which, in combination with normal implant loading, led to cases of severe implant discoloration, pitting attack, cracking and fretting-crevice corrosion. The results suggest that acidic environments induced by bacterial biofilms and/or inflammatory processes may trigger oxidation of the surface of titanium dental implants. The corrosive process can lead to permanent breakdown of the oxide film, which, besides releasing metal ions and debris in vivo, may also hinder re-integration of the implant surface with surrounding bone. Full article

(This article belongs to the Special Issue Titanium Materials for Biomedical Application 2013)

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Graphical abstract

11 pages, 486 KiB

Open AccessArticle

A Bone-Thickness Map as a Guide for Bone-Anchored Port Implantation Surgery in the Temporal Bone

by Jérémie Guignard^1,2, Andreas Arnold^1,3, Christian Weisstanner⁴, Marco Caversaccio^1,3,* and Christof Stieger^1,3,5

¹ ARTORG Center for Biomedical Engineering, Artificial Hearing Research, University of Bern, Bern 3008, Switzerland

² Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern 3012, Switzerland

³ Department of ENT, Head and Neck Surgery, Inselspital, University Hospital of Bern, Bern 3008, Switzerland

⁴ Department of Neuroradiology, Inselspital, University Hospital of Bern, Bern 3008, Switzerland

⁵ Department of ORL, University Hospital Basel, HNO Klinik, Hebelstr. 10, Basel 4031, Switzerland

Materials 2013, 6(11), 5291-5301; https://doi.org/10.3390/ma6115291 - 19 Nov 2013

Cited by 16 | Viewed by 6442

Abstract

The bone-anchored port (BAP) is an investigational implant, which is intended to be fixed on the temporal bone and provide vascular access. There are a number of implants taking advantage of the stability and available room in the temporal bone. These devices range [...] Read more.

The bone-anchored port (BAP) is an investigational implant, which is intended to be fixed on the temporal bone and provide vascular access. There are a number of implants taking advantage of the stability and available room in the temporal bone. These devices range from implantable hearing aids to percutaneous ports. During temporal bone surgery, injuring critical anatomical structures must be avoided. Several methods for computer-assisted temporal bone surgery are reported, which typically add an additional procedure for the patient. We propose a surgical guide in the form of a bone-thickness map displaying anatomical landmarks that can be used for planning of the surgery, and for the intra-operative decision of the implant’s location. The retro-auricular region of the temporal and parietal bone was marked on cone-beam computed tomography scans and tridimensional surfaces displaying the bone thickness were created from this space. We compared this method using a thickness map (n = 10) with conventional surgery without assistance (n = 5) in isolated human anatomical whole head specimens. The use of the thickness map reduced the rate of Dura Mater exposition from 100% to 20% and suppressed sigmoid sinus exposures. The study shows that a bone-thickness map can be used as a low-complexity method to improve patient’s safety during BAP surgery in the temporal bone. Full article

(This article belongs to the Special Issue Computational Modeling and Simulation in Materials Study)

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12 pages, 783 KiB

Open AccessArticle

Study of the Wavelength Dependence in Laser Ablation of Advanced Ceramics and Glass-Ceramic Materials in the Nanosecond Range

by Daniel Sola^*

and Jose I. Peña

Department of Science and Technology of Materials and Fluids, Material Science Institute of Aragon, University of Zaragoza-Spanish National Research Council (CSIC), Maria de Luna 3, Zaragoza 50.018, Spain

Materials 2013, 6(11), 5302-5313; https://doi.org/10.3390/ma6115302 - 19 Nov 2013

Cited by 25 | Viewed by 6779

Abstract

In this work, geometrical dimensions and ablation yields as a function of the machining method and reference position were studied when advanced ceramics and glass-ceramic materials were machined with pulsed lasers in the nanosecond range. Two laser systems, emitting at 1064 and 532 [...] Read more.

In this work, geometrical dimensions and ablation yields as a function of the machining method and reference position were studied when advanced ceramics and glass-ceramic materials were machined with pulsed lasers in the nanosecond range. Two laser systems, emitting at 1064 and 532 nm, were used. It was shown that the features obtained depend on whether the substrate is processed by means of pulse bursts or by grooves. In particular, when the samples were processed by grooves, machined depth, removed volume and ablation yields reached their maximum, placing the sample out of focus. It was shown that these characteristics do not depend on the processing conditions, the wavelength or the optical configuration, and that this is intrinsic behavior of the processing method. Furthermore, the existence of a close relation between material hardness and ablation yields was demonstrated. Full article

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21 pages, 986 KiB

Open AccessArticle

Geosynthetic Reinforcement of Sand-Mat Layer above Soft Ground

by Jong-Beom Park¹, Hyun-Soo Park² and Daehyeon Kim^3,*

¹ Shinmyeong Construction Engineering Co., Ltd.; Suncheon 540-080, Korea

² New Millennium Construction Co., Ltd.; Gwangju 500-862, Korea

³ Department of Civil Engineering, Chosun University, Gwangju 501-759, Korea

Materials 2013, 6(11), 5314-5334; https://doi.org/10.3390/ma6115314 - 19 Nov 2013

Cited by 15 | Viewed by 6439

Abstract

In order to improve the bearing capacity of soft ground for the purpose of getting trafficability of construction vehicles, the reinforcement of geosynthetics for sand-mat layers on soft ground has often been used. As the strength of the geosynthetics increases, and the sand-mat [...] Read more.

In order to improve the bearing capacity of soft ground for the purpose of getting trafficability of construction vehicles, the reinforcement of geosynthetics for sand-mat layers on soft ground has often been used. As the strength of the geosynthetics increases, and the sand-mat system becomes stronger, the bearing capacity of sand-mat systems will be increased. The depths of geosynthetics, reinforced in sand-mat layers, were varied with respect to the width of footing. The tensile strengths of geosynthetics were also varied to evaluate the effect of reinforcement on the bearing capacity of soft ground. The dispersion angles, with varying sand-mat thicknesses, were also determined in consideration of the tensile strength of geosynthetics and the depths of reinforcement installations. The bearing capacity ratios, with the variation of footing width and reinforced embedment depth, were determined for the geosynthetics-only, reinforced soft ground, 1-layer sand-mat system and 2-layer sand-mat system against the non-reinforced soft ground. From the test results of various models, a principle that better explains the concept of geosynthetic reinforcement has been found. On the basis of this principle, a new bearing capacity equation for practical use in the design of geosynthetically reinforced soft ground has been proposed by modifying Yamanouchi’s equation. Full article

(This article belongs to the Special Issue Construction Materials)

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17 pages, 1544 KiB

Open AccessArticle

Phosphorus Effects of Mesoporous Bioactive Glass on Occlude Exposed Dentin

by Wen-Cheng Chen^1,†

, Cheng-Hwei Chen^2,†, Jung-Chang Kung³, Yu-Cheng Hsiao⁴, Chi-Jen Shih^5,* and Chi-Sheng Chien^6,7,*

¹ Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan

² School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan

³ Department of Family Dentistry, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan

⁴ Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan

⁵ Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan

⁶ Department of Orthopaedics, Chi Mei Foundation Hospital, Tainan 71004, Taiwan

⁷ Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan

^† These authors contributed equally to this work.

Materials 2013, 6(11), 5335-5351; https://doi.org/10.3390/ma6115335 - 19 Nov 2013

Cited by 9 | Viewed by 6533

Abstract

In recent studies, sealing of exposed dentinal tubules is generally considered as one of the most effective strategies to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG) is a potential material for treating dentin hypersensitivity due to its highly specific areas for dissolution and [...] Read more.

In recent studies, sealing of exposed dentinal tubules is generally considered as one of the most effective strategies to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG) is a potential material for treating dentin hypersensitivity due to its highly specific areas for dissolution and re-precipitated reaction for reduction in dentin permeability. The groups of commercial products of PerioGlas^®, synthetic MBG and MBG without phosphorus (MBGNP) were compared. The MBG and MBGNP powders were prepared by the sol-gel method and mixed with different calculated ratios of phosphoric acid (PA) and then was brushed onto dentin surfaces. We used X-ray diffractometer (XRD), scanning electronic microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) to investigate the physiochemistry and the occlusion ability of dentinal tubules. The results showed that MBG paste mixed with PA solution has a better ability for occluding dentinal tubules than MBGNP; it has a short reaction time and good operability. The major crystallite phase of MBG agents was monocalcium phosphate monohydrate [Ca(H₂PO₄)₂·H₂O] in the early stages of the reactions. MBG pastes that were mixed with 30% and 40% PA had the ability to create excellent penetration depth greater than 80 μm. These agents have the potential to treat dentin hypersensitivity. Full article

(This article belongs to the Special Issue Ceramics for Healthcare 2013)

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15 pages, 766 KiB

Open AccessArticle

Synthesis, Molecular Structure and Cytotoxicity of Molecular Materials Based on Water Soluble Half-Sandwich Rh(III) and Ir(III) Tetranuclear Metalla-Cycles

by Gajendra Gupta¹, Benjamin S. Murray², Paul J. Dyson² and Bruno Therrien^1,*

¹ Institute of Chemistry, University of Neuchatel, Avenue de Bellevaux 51, Neuchatel CH-2000, Switzerland

² Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland

Materials 2013, 6(11), 5352-5366; https://doi.org/10.3390/ma6115352 - 20 Nov 2013

Cited by 29 | Viewed by 7154

Abstract

The neutral dinuclear complexes [(η⁵-C₅Me₅)₂Rh₂(μ-dhnq)Cl₂] (1) and [(η⁵-C₅Me₅)₂Ir₂(μ-dhnq)Cl₂] (2) (dhnqH₂ = 5,8-dihydroxy-1,4-naphthoquinone) were obtained [...] Read more.

The neutral dinuclear complexes [(η⁵-C₅Me₅)₂Rh₂(μ-dhnq)Cl₂] (1) and [(η⁵-C₅Me₅)₂Ir₂(μ-dhnq)Cl₂] (2) (dhnqH₂ = 5,8-dihydroxy-1,4-naphthoquinone) were obtained from the reaction of [(η⁵-C₅Me₅)M(μ-Cl)Cl]₂ (M = Rh, Ir) with dhnqH₂ in the presence of CH₃COONa. Treatment of 1 or 2 in methanol with linear ditopic ligands L (L = pyrazine, 4,4′-bipyridine or 1,2-bis(4-pyridyl)ethylene), in the presence of AgCF₃SO₃, affords the corresponding tetranuclear metalla-rectangles [(η⁵-C₅Me₅)₄M₄(μ-dhnq)₂(μ-L)₂]⁴⁺ (L = pyrazine, M = Rh, 3; M = Ir, 4; L = 4,4′-bipyridine, M = Rh, 5; M = Ir, 6; L = 1,2-bis(4-pyridyl)ethylene, M = Rh, 7; M = Ir, 8). All complexes were isolated as their triflate salts and were fully characterized by infrared, ¹H and ¹³C NMR spectroscopy, and some representative complexes by single-crystal X-ray structure analysis. The X-ray structures of 3, 5 and 6 confirm the formation of the tetranuclear metalla-cycles, and suggest that complexes 5 and 6 possess a cavity of sufficient size to encapsulate small guest molecules. In addition, the antiproliferative activity of the metalla-cycles 3–8 was evaluated against the human ovarian A2780 (cisplatin sensitive) and A2780cisR (cisplatin resistant) cancer cell lines and on non-tumorigenic human embryonic kidney HEK293 cells. All cationic tetranuclear metalla-rectangles were found to be highly cytotoxic, with IC₅₀ values in the low micromolar range. Full article

(This article belongs to the Special Issue Supramolecular Cage Complexes)

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15 pages, 846 KiB

Open AccessArticle

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

by Keisuke Fujisaki^1,* and Tomoyuki Ikeda^1,2

¹ Toyota Technological Institute, 2-12-1 Hisakata, Tenpaku-ku, Nagoya-city 468-8511, Japan

² Kojima Press Industry Co. Ltd., 15 Hirokuden, Ukigai-cho, Miyoshi-city 470-0207, Japan

Materials 2013, 6(11), 5367-5381; https://doi.org/10.3390/ma6115367 - 21 Nov 2013

Cited by 5 | Viewed by 4935

Abstract

To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to [...] Read more.

To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model) and the homogeneous model (macro-model). However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity. Full article

(This article belongs to the Special Issue Microwave Processing of Materials)

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16 pages, 807 KiB

Open AccessArticle

Optimized Slurries for Spray Drying: Different Approaches to Obtain Homogeneous and Deformable Alumina-Zirconia Granules

by Valentina Naglieri^1,2, Dan Gutknecht³, Vincent Garnier³

, Paola Palmero^1,*, Jérôme Chevalier^3,4 and Laura Montanaro¹

¹ Department of Applied Science and Technology, INSTM R.U. PoliTO, LINCE Lab., Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy

² Now at Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

³ Université de Lyon, INSA de Lyon, MATEIS UMR CNRS 5510, Bât. Blaise Pascal 7, Av. Jean Capelle, 69621 Villeurbanne, France

⁴ Institut Universitaire de France, 103 bd Saint-Michel, 75005 Paris, France

Materials 2013, 6(11), 5382-5397; https://doi.org/10.3390/ma6115382 - 21 Nov 2013

Cited by 33 | Viewed by 8329

Abstract

Spray drying is widely used for producing granulated feed materials for compaction process, which is the current industrial method for manufacturing alumina-zirconia femoral heads. The optimization of the granules compaction behavior requires the control of the slurry rheology. Moreover, for a dual-phase ceramic [...] Read more.

Spray drying is widely used for producing granulated feed materials for compaction process, which is the current industrial method for manufacturing alumina-zirconia femoral heads. The optimization of the granules compaction behavior requires the control of the slurry rheology. Moreover, for a dual-phase ceramic suspension, the even phase distribution has to be kept through the atomization step. Here we present two approaches addressing the key issues involved in the atomization of a composite system. Alumina-10 vol % zirconia powders were prepared by either a powder mixing route, or by the surface modification of a commercial α-alumina powder with a zirconium salt. Slurries from both powders were spray dried. The correlation between slurry rheology and pH, granules morphology and sintered microstructures was here investigated and discussed on the ground of the two feed materials characteristics. The processing conditions were optimized to obtain dense and homogeneous alumina-zirconia micro-nano composites by both processing routes. Full article

(This article belongs to the Section Advanced Composites)

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12 pages, 391 KiB

Open AccessArticle

Comparative Analysis of the Oxygen Supply and Viability of Human Osteoblasts in Three-Dimensional Titanium Scaffolds Produced by Laser-Beam or Electron-Beam Melting

by Anika Jonitz-Heincke^1,*, Jan Wieding¹, Christoph Schulze^1,2, Doris Hansmann¹ and Rainer Bader¹

¹ Biomechanics and Implant Technology Research Laboratory, Department of Orthopaedics, University Medicine Rostock, Doberaner Strasse 142, Rostock 18057, Germany

² Department of Orthopaedic Surgery, Armed Forces Hospital Westerstede, Lange Str. 38, Westerstede 26655, Germany

Materials 2013, 6(11), 5398-5409; https://doi.org/10.3390/ma6115398 - 21 Nov 2013

Cited by 28 | Viewed by 6482

Abstract

Synthetic materials for bone replacement must ensure a sufficient mechanical stability and an adequate cell proliferation within the structures. Hereby, titanium materials are suitable for producing patient-individual porous bone scaffolds by using generative techniques. In this in vitro study, the viability of human [...] Read more.

Synthetic materials for bone replacement must ensure a sufficient mechanical stability and an adequate cell proliferation within the structures. Hereby, titanium materials are suitable for producing patient-individual porous bone scaffolds by using generative techniques. In this in vitro study, the viability of human osteoblasts was investigated in porous 3D Ti6Al4V scaffolds, which were produced by electron-beam (EBM) or laser-beam melting (LBM). For each examination, two cylindrical scaffolds (30 mm × 10 mm in size, 700 µm × 700 µm macropores) were placed on each other and seeded with cells. The oxygen consumption and the acidification in the center of the structures were investigated by means of microsensors. Additionally, the synthesis of pro-collagen type 1 was analyzed. On the LBM titanium scaffolds, vital bone cells were detected in the center and in the periphery after 8 days of cultivation. In the EBM titanium constructs, however, vital cells were only visible in the center. During the cultivation period, the cells increasingly produced procollagen type 1 in both scaffolds. In comparison to the periphery, the oxygen content in the center of the scaffolds slightly decreased. Furthermore, a slight acidification of the medium was detectable. Compared to LBM, the EBM titanium scaffolds showed a less favorable behavior with regard to cell seeding. Full article

(This article belongs to the Special Issue Titanium Materials for Biomedical Application 2013)

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17 pages, 951 KiB

Open AccessArticle

Rapid Microwave Synthesis, Characterization and Reactivity of Lithium Nitride Hydride, Li₄NH

by Nuria Tapia-Ruiz¹, Natalie Sorbie¹, Nicolas Vaché^1,2, Tuan K. A. Hoang¹ and Duncan H. Gregory^1,*

¹ WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK

² Ecole Nationale Supérieure de Chimie de Clermont-Ferrand, Université Blaise Pascal, BP 187, Aubière Cedex 63174, France

Materials 2013, 6(11), 5410-5426; https://doi.org/10.3390/ma6115410 - 21 Nov 2013

Cited by 8 | Viewed by 8271

Abstract

Lithium nitride hydride, Li₄NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space [...] Read more.

Lithium nitride hydride, Li₄NH, was synthesised from lithium nitride and lithium hydride over minute timescales, using microwave synthesis methods in the solid state for the first time. The structure of the microwave-synthesised powders was confirmed by powder X-ray diffraction [tetragonal space group I4₁/a; a = 4.8864(1) Å, c = 9.9183(2) Å] and the nitride hydride reacts with moist air under ambient conditions to produce lithium hydroxide and subsequently lithium carbonate. Li₄NH undergoes no dehydrogenation or decomposition [under Ar_(g)] below 773 K. A tetragonal–cubic phase transition, however, occurs for the compound at ca. 770 K. The new high temperature (HT) phase adopts an anti-fluorite structure (space group Fm 3̅ m; a = 4.9462(3) Å) with N³⁻ and H⁻ ions disordered on the 4a sites. Thermal treatment of Li₄NH under nitrogen yields a stoichiometric mixture of lithium nitride and lithium imide (Li₃N and Li₂NH respectively). Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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13 pages, 598 KiB

Open AccessCommunication

Voltammetric Studies on Gold Electrodes Coated with Chitosan-Containing Layer-by-Layer Films

by Shigehiro Takahashi¹, Ryota Watahiki¹, Kohji Tomida¹, Baozhen Wang^1,2 and Jun-ichi Anzai^1,*

¹ Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan

² Department of Nutrition and Food Hygiene, School of Public Health, Shandong University, 44 WenhuaXilu, Jinan, Shandong 250012, China

Materials 2013, 6(11), 5427-5439; https://doi.org/10.3390/ma6115427 - 21 Nov 2013

Cited by 4 | Viewed by 5583

Abstract

Gold (Au) electrodes coated with layer-by-layer (LbL) thin films composed of chitosan (CHI) were prepared to evaluate the redox properties of hexaammine ruthenium ions, Ru(NH₃)₆³⁺, and ferricyanide ions, Fe(CN)₆³⁻ LbL films were prepared on an Au [...] Read more.

Gold (Au) electrodes coated with layer-by-layer (LbL) thin films composed of chitosan (CHI) were prepared to evaluate the redox properties of hexaammine ruthenium ions, Ru(NH₃)₆³⁺, and ferricyanide ions, Fe(CN)₆³⁻ LbL films were prepared on an Au electrode by electrostatic LbL deposition using polycationic CHI and poly(vinyl sulfate) (PVS) or poly(acrylic acid) (PAA) as anionic component. Redox peak current in cyclic voltammetry of Ru(NH₃)₆³⁺ on the CHI/PVS and CHI/PAA film-coated electrodes increased with increasing thickness of the films. Interestingly, the cyclic voltammograms showed two pair of redox peaks, originating from Ru(NH₃)₆³⁺ diffusing across the LbL layers and from those confined in the film. The results were rationalized in terms of the electrostatic interactions between Ru(NH₃)₆³⁺ and excess negative charges in the LbL films originating from PVS and PAA. In contrast, Fe(CN)₆³⁻ was not confined in the LbL films due to electrostatic repulsion of Fe(CN)₆³⁻ and excess negative charges. Significant amounts of Ru(NH₃)₆³⁺ were confined in the films at pH 7.0, whereas few ions were bound at pH 3.0 due to the reduced net negative charge in the films. The results suggest a potential use of the CHI-containing LbL films as scaffold for immobilizing positively charged ionic species on the electrode surface. Full article

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7 pages, 300 KiB

Open AccessArticle

Efficiency Improvement of HIT Solar Cells on p-Type Si Wafers

by Chun-You Wei¹, Chu-Hsuan Lin^1,*, Hao-Tse Hsiao¹, Po-Chuan Yang², Chih-Ming Wang¹ and Yen-Chih Pan¹

¹ Department of Opto-Electronic Engineering, National Dong Hwa University, Shoufeng, Hualien 97401, Taiwan

² No. 23-10, Wenhua Rd., Xindian District, New Taipei City 23144, Taiwan

Materials 2013, 6(11), 5440-5446; https://doi.org/10.3390/ma6115440 - 22 Nov 2013

Cited by 23 | Viewed by 6395

Abstract

Single crystal silicon solar cells are still predominant in the market due to the abundance of silicon on earth and their acceptable efficiency. Different solar-cell structures of single crystalline Si have been investigated to boost efficiency; the heterojunction with intrinsic thin layer (HIT) [...] Read more.

Single crystal silicon solar cells are still predominant in the market due to the abundance of silicon on earth and their acceptable efficiency. Different solar-cell structures of single crystalline Si have been investigated to boost efficiency; the heterojunction with intrinsic thin layer (HIT) structure is currently the leading technology. The record efficiency values of state-of-the art HIT solar cells have always been based on n-type single-crystalline Si wafers. Improving the efficiency of cells based on p-type single-crystalline Si wafers could provide broader options for the development of HIT solar cells. In this study, we varied the thickness of intrinsic hydrogenated amorphous Si layer to improve the efficiency of HIT solar cells on p-type Si wafers. Full article

(This article belongs to the Special Issue Solar Energy Materials 2013)

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Review

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32 pages, 2067 KiB

Open AccessReview

Molding of Plasmonic Resonances in Metallic Nanostructures: Dependence of the Non-Linear Electric Permittivity on System Size and Temperature

by Alessandro Alabastri^1,*, Salvatore Tuccio¹, Andrea Giugni¹, Andrea Toma¹, Carlo Liberale¹, Gobind Das¹, Francesco De Angelis¹, Enzo Di Fabrizio^2,3 and Remo Proietti Zaccaria^1,*

¹ Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163, Italy

² King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering (PSE) Division, Biological and Environmental Science and Engineering (BESE) Division, Thuwal 23955-6900, Kingdom of Saudi Arabia

³ Bio-Nanotechnology and Engineering for Medicine (BIONEM), Department of Experimental and Clinical Medicine, University of Magna Graecia Viale Europa, Germaneto, Catanzaro 88100, Italy

Materials 2013, 6(11), 4879-4910; https://doi.org/10.3390/ma6114879 - 25 Oct 2013

Cited by 139 | Viewed by 14305

Abstract

In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in [...] Read more.

In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in the damping coefficients. Electronic scattering processes are described and included in the dielectric function, showing their role in determining plasmon lifetime at resonance. Relationships among permittivity, electric conductivity and refractive index are examined. Finally, a temperature dependent permittivity model is presented and is employed to predict temperature and non-linear field intensity dependence on commonly used plasmonic geometries, such as nanospheres. Full article

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24 pages, 2090 KiB

Open AccessReview

Magneto-Optical Thin Films for On-Chip Monolithic Integration of Non-Reciprocal Photonic Devices

by Lei Bi^1,*, Juejun Hu², Peng Jiang^3,†, Hyun Suk Kim^3,††, Dong Hun Kim³, Mehmet Cengiz Onbasli³, Gerald F. Dionne³ and Caroline A. Ross³

¹ State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, No. 4 Sec. 2 Jianshe N. Street, Chengdu 610054, China

² Department of Materials Science & Engineering, University of Delaware, 305 DuPont Hall, Newark, DE 19716, USA

³ Department of Materials Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA

^† Current Address: Huawei Technologies Co., Ltd., Bantian, Longgang District, Shenzhen 518129, China

^†† Current Address: Samsung Electronics Co., Ltd., Mt. 14-1, Nongseo-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do 449-712, Korea

Materials 2013, 6(11), 5094-5117; https://doi.org/10.3390/ma6115094 - 8 Nov 2013

Cited by 86 | Viewed by 11777

Abstract

Achieving monolithic integration of nonreciprocal photonic devices on semiconductor substrates has been long sought by the photonics research society. One way to achieve this goal is to deposit high quality magneto-optical oxide thin films on a semiconductor substrate. In this paper, we review [...] Read more.

Achieving monolithic integration of nonreciprocal photonic devices on semiconductor substrates has been long sought by the photonics research society. One way to achieve this goal is to deposit high quality magneto-optical oxide thin films on a semiconductor substrate. In this paper, we review our recent research activity on magneto-optical oxide thin films toward the goal of monolithic integration of nonreciprocal photonic devices on silicon. We demonstrate high Faraday rotation at telecommunication wavelengths in several novel magnetooptical oxide thin films including Co substituted CeO₂_−δ, Co- or Fe-substituted SrTiO₃₋_δ, as well as polycrystalline garnets on silicon. Figures of merit of 3~4 deg/dB and 21 deg/dB are achieved in epitaxial Sr(Ti_0.2Ga_0.4Fe_0.4)O₃₋_δ and polycrystalline (CeY₂)Fe₅O₁₂ films, respectively. We also demonstrate an optical isolator on silicon, based on a racetrack resonator using polycrystalline (CeY₂)Fe₅O₁₂/silicon strip-loaded waveguides. Our work demonstrates that physical vapor deposited magneto-optical oxide thin films on silicon can achieve high Faraday rotation, low optical loss and high magneto-optical figure of merit, therefore enabling novel high-performance non-reciprocal photonic devices monolithically integrated on semiconductor substrates. Full article

(This article belongs to the Special Issue Photonic Materials and Applications)

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28 pages, 638 KiB

Open AccessReview

The Change from Past to Future for Adsorbent Materials in Treatment of Dyeing Wastewaters

by George Z. Kyzas^1,2,*

, Jie Fu³ and Kostas A. Matis¹

¹ Laboratory of General & Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR 541 24, Greece

² Department of Petroleum and Natural Gas Technology, Technological Educational Institute of Kavala, Kavala GR 654 04, Greece

³ Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, USA

Materials 2013, 6(11), 5131-5158; https://doi.org/10.3390/ma6115131 - 8 Nov 2013

Cited by 177 | Viewed by 12303

Abstract

Adsorption is one of the most promising decolorization techniques in dyeing wastewater treatment. Adsorption techniques for wastewater treatment have become more popular in recent years owing to their efficiency in the removal of pollutants too stable for biological methods. Dye adsorption is a [...] Read more.

Adsorption is one of the most promising decolorization techniques in dyeing wastewater treatment. Adsorption techniques for wastewater treatment have become more popular in recent years owing to their efficiency in the removal of pollutants too stable for biological methods. Dye adsorption is a result of two mechanisms (adsorption and ion exchange) and is influenced by many factors as dye/adsorbent interaction, adsorbent’s surface area, particle size, temperature, pH, and contact time. The main advantage of adsorption recently became the use of low-cost materials, which reduces the procedure cost. The present review firstly introduced the technology process, research history and research hotspot of adsorption. Then, the application of adsorption in treatment of dyeing wastewaters in the past decades was summarized, revealing the impressive changes in modes, trends, and conditions. From this review article, the different philosophy of synthesis of adsorbent materials became evident. Full article

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28 pages, 917 KiB

Open AccessReview

Recent Development of Flax Fibres and Their Reinforced Composites Based on Different Polymeric Matrices

by Jinchun Zhu^1,*, Huijun Zhu², James Njuguna³

and Hrushikesh Abhyankar^1,*

¹ Centre of Automotive Technology, Cranfield University, Cranfield, MK43 0AL, UK

² Cranfiled Health, Cranfield University, Cranfield, MK43 0AL, UK

³ Institute for Innovation, Design and Sustainability, Robert Gordon University, Aberdeen AB10 7GJ, UK

Materials 2013, 6(11), 5171-5198; https://doi.org/10.3390/ma6115171 - 12 Nov 2013

Cited by 229 | Viewed by 16481

Abstract

This work describes flax fibre reinforced polymeric composites with recent developments. The properties of flax fibres, as well as advanced fibre treatments such as mercerization, silane treatment, acylation, peroxide treatment and coatings for the enhancement of flax/matrix incompatibility are presented. The characteristic properties [...] Read more.

This work describes flax fibre reinforced polymeric composites with recent developments. The properties of flax fibres, as well as advanced fibre treatments such as mercerization, silane treatment, acylation, peroxide treatment and coatings for the enhancement of flax/matrix incompatibility are presented. The characteristic properties and characterizations of flax composites on various polymers including polypropylene (PP) and polylactic acid, epoxy, bio-epoxy and bio-phenolic resin are discussed. A brief overview is also given on the recent nanotechnology applied in flax composites. Full article

(This article belongs to the Section Biomaterials)

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Other

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16 pages, 613 KiB

Open AccessConcept Paper

An Empirical Approach to Correlating Thermo-Mechanical Fatigue Behaviour of a Polycrystalline Ni-Base Superalloy

by Mark Whittaker¹, Robert Lancaster^1,*

, William Harrison¹

, Christopher Pretty¹ and Stephen Williams²

¹ Materials Research Centre, College of Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, UK

² Rolls-Royce plc, Elton Road, Derby DE24 8BJ, UK

Materials 2013, 6(11), 5275-5290; https://doi.org/10.3390/ma6115275 - 15 Nov 2013

Cited by 8 | Viewed by 6049

Abstract

Assessment of thermo-mechanical fatigue behaviour of the polycrystalline nickel alloy RR1000 reveals a significant effect of phase angle on fatigue life. The current paper explores two scenarios: the first where the mechanical strain range is held constant and comparisons of the fatigue life [...] Read more.

Assessment of thermo-mechanical fatigue behaviour of the polycrystalline nickel alloy RR1000 reveals a significant effect of phase angle on fatigue life. The current paper explores two scenarios: the first where the mechanical strain range is held constant and comparisons of the fatigue life are made for different phase angle tests; and secondly, the difference between the behaviour of In-phase (IP) and −180° Out-Of-Phase (OOP) tests over a variety of applied strain ranges. It is shown that different lifing approaches are currently required for the two scenarios, with a mean stress based approach being more applicable in the first case, whereas a Basquin-type model proves more applicable in the second. However, it is also demonstrated that the crack propagation phase should also be considered in these types of tests for high strain ranges and projects that future modelling approaches should attempt to unify mean stress, stress range and a crack propagation phase. Full article

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Materials, Volume 6, Issue 11 (November 2013) – 35 articles , Pages 4879-5446

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