Characterisation of intermetallic phases in multicomponent Al-Si alloys for piston applications

Al-Si based casting alloys are widely used for piston applications. This is due to their combination of properties, which include good castability, high strength, light weight, good wear resistance and low thermal expansion. In order for such alloys to meet increasingly demanding operational requirements, such as higher service temperatures and pressures, multicomponent Al-Si alloys, which contain several other alloying additions (Cu, Ni, Mg, Mn and Fe), have been used to further enhance the high temperature strength and fatigue resistance. Improved material properties are strongly dependent upon the morphologies, the thermal and mechanical properties, and the distribution of the intermetallic phases present in these alloys, which are in turn a function of alloy composition and cooling rate. Therefore, the main aim of this work was to characterise the many complex intermetallic phases in multicomponent Al-Si alloys. Five main areas of interest were investigated in this research. Firstly, thermodynamic modelling has been used to predict phase formation in complex alloys, which has been compared with measurements from differential scanning calorimetry (DSC). Secondly, the presence of additional elements in multicomponent Al-Si alloy systems allow many complex intermetallic phases to form, which make microstructural characterisationn on-trivial, as some of the phases have either similar crystal structures or exhibit subtle changes in their chemistries. A combination of electron backscatter diffraction (EBSD) and energy dispersive X-ray analysis (EDX) have therefore been used for discrimination between the various phases. It is shown that this is a powerful technique for microstructure characterisation and provides detailed information which can be related to the microstructuree volution during initial casting and subsequent heat treatment. Additionally, the complex morphologies of intermetallics have also been observed using 3D X-ray tomography. In this present work, a number of different experimental techniques were used to provide a rapid means of phase discrimination in order to validate microstructural evolution models. Thirdly, the mechanical properties of individual intermetallics have been investigated as a function of temperature using high -temperature nanoindentation. In particular, the hardness and modulus of a number of phases have been measured for a range of alloy compositions. The creep behaviour of intermetallic phases was also investigated, since this is important in the determination of the high temperature mechanical properties of alloys. Fourthly, the coefficients of thermal expansion of intermetallic phases were measured by high temperature X-ray diffraction, and thermal expansion anisotropy was also explored to investigate the formation of microcracking. Finally, in order to investigate the effect of both applied mechanical and thermal loads on the formation of cracks, Eshelby modelling has been used to predict the internal stresses of the different intermetallic phases and alloys, with the aid of the experimental data obtained in this work. The phase identity, composition, and the corresponding physical and mechanical properties can be used to inform alloy design strategies which, may facilitate the development of new alloys with improved properties

Mixed-Valence Uranium Germanate and Silicate: Cs_<i>x</i>(U^VO)(U^IV/VO)₂(Ge₂O₇)₂ (<i>x</i> = 3.18) and Cs₄(U^VO)(U^IV/VO)₂(Si₂O₇)₂

A new mixed-valence uranium germanate and the silicate analogue have been synthesized under hydrothermal conditions at 600 °C and 165 MPa. Their crystal structures contain infinite −U^V–O–U^IV/V–O–U^IV/V–O–U^V– chains that are connected by Ge₂O₇ or Si₂O₇ groups to form a 3D framework with six-ring channels where the Cs⁺ cations are located. Two of the Cs sites in the germanate are partially occupied. Bond-valence-sum calculation and an U 4f X-ray photoelectron spectroscopy study confirm the valence states of the uranium

Cs₃UGe₇O₁₈: A Pentavalent Uranium Germanate Containing Four- and Six-Coordinate Germanium

A pentavalent uranium germanate, Cs₃UGe₇O₁₈, was synthesized under high-temperature, high-pressure hydrothermal conditions at 585 °C and 160 MPa and structurally characterized by single-crystal X-ray diffraction and infrared spectroscopy. The valence state of uranium was confirmed by X-ray photoelectron spectroscopy and electron paramagnetic resonance. The room-temperature EPR spectrum can be simulated with two components using an axial model that are consistent with two distinct sites of uranium­(V). In the structure of the title compound, each ^[6]GeO₆ octahedron is bonded to six three-membered single-ring ^[4]Ge₃O₉^6– units to form germanate triple layers in the <i>ab</i> plane. Each layer contains nine-ring windows; however, these windows are blocked by adjacent layers. The triple layers are further connected by UO₆ octahedra to form a three-dimensional framework with intersecting six-ring channels along the ⟨11̅0⟩ directions. The Cs⁺ cation sites are fully occupied, ordered, and located in the cavities of the framework. Pentavalent uranium germanates or silicates are very rare, and only two uranium silicates and one germanate analogue have been published. However, all of them are iso-structural with those of the Nb or Ta analogues. In contrast, the title compound adopts a new structural type and contains both four- and six-coordinate germanium. Crystal data of Cs₃UGe₇O₁₈: trigonal, <i>P</i>3̅<i>c</i>1 (No. 165), <i>a</i> = 12.5582(4) Å, <i>c</i> = 19.7870(6) Å, <i>V</i> = 2702.50(15) ų, <i>Z</i> = 6, <i>D</i>_calc = 5.283 g·cm^–3, μ­(Mo Kα) = 26.528 mm^–1, <i>R</i>₁ = 0.0204, <i>wR</i>₂ = 0.0519 for 1958 reflections with <i>I</i> > 2σ­(<i>I</i>). GooF = 1.040, ρ_max,min = 1.018, and −1.823 e·Å^–3

Cs₃UGe₇O₁₈: A Pentavalent Uranium Germanate Containing Four- and Six-Coordinate Germanium

A pentavalent uranium germanate, Cs₃UGe₇O₁₈, was synthesized under high-temperature, high-pressure hydrothermal conditions at 585 °C and 160 MPa and structurally characterized by single-crystal X-ray diffraction and infrared spectroscopy. The valence state of uranium was confirmed by X-ray photoelectron spectroscopy and electron paramagnetic resonance. The room-temperature EPR spectrum can be simulated with two components using an axial model that are consistent with two distinct sites of uranium­(V). In the structure of the title compound, each ^[6]GeO₆ octahedron is bonded to six three-membered single-ring ^[4]Ge₃O₉^6– units to form germanate triple layers in the <i>ab</i> plane. Each layer contains nine-ring windows; however, these windows are blocked by adjacent layers. The triple layers are further connected by UO₆ octahedra to form a three-dimensional framework with intersecting six-ring channels along the ⟨11̅0⟩ directions. The Cs⁺ cation sites are fully occupied, ordered, and located in the cavities of the framework. Pentavalent uranium germanates or silicates are very rare, and only two uranium silicates and one germanate analogue have been published. However, all of them are iso-structural with those of the Nb or Ta analogues. In contrast, the title compound adopts a new structural type and contains both four- and six-coordinate germanium. Crystal data of Cs₃UGe₇O₁₈: trigonal, <i>P</i>3̅<i>c</i>1 (No. 165), <i>a</i> = 12.5582(4) Å, <i>c</i> = 19.7870(6) Å, <i>V</i> = 2702.50(15) ų, <i>Z</i> = 6, <i>D</i>_calc = 5.283 g·cm^–3, μ­(Mo Kα) = 26.528 mm^–1, <i>R</i>₁ = 0.0204, <i>wR</i>₂ = 0.0519 for 1958 reflections with <i>I</i> > 2σ­(<i>I</i>). GooF = 1.040, ρ_max,min = 1.018, and −1.823 e·Å^–3

Relationship Between Symptoms Of Androgen Deficiency, Anxiety, Depression, and Quality Of Life among Male Psychiatric Outpatients

<p>Presented in the 53rd Annual Meeting of Taiwan Society of Psychiatry.</p

Prevalence and Risk Factors of Testosterone Deficiency at a Men’s Health Clinic in Taiwan

<p>A cross-sectional study of testosterone deficiency at a men's health polyclinic in an Asian population.</p> <p>Presented in the Taiwanese Society of Biological. Psychiatry and. Neuropsychopharmacology. /. Taiwanese College of Neuropsychiatry (TSBPN- TCNP) 2014 Annual Congress.</p

Additional file 2: Figure S2. of Vibrio vulnificus MARTX cytotoxin causes inactivation of phagocytosis-related signaling molecules in macrophages

Morphological change of HeLa cells infected by various MARTXVv1 domain-deletion mutants. Morphology of the HeLa cells coincubated with bacteria at MOI 10 for 90 min was examined under a light microscope. YJ016: WT strain; HL128: MD mutant. Bar = 50 μm. Data are representative of three independent experiments. (TIFF 3870 kb

Additional file 1: Figure S1. of Vibrio vulnificus MARTX cytotoxin causes inactivation of phagocytosis-related signaling molecules in macrophages

Expression of MARTXVv1 mutant proteins in the domain-deletion mutants. Total cell lysate collected from the bacteria cultured in LB for 4 h was fractionated by electrophoresis on an 8% SDS-polyacrylamide gel and then subjected to immunoblotting with anti-ERM antibody. YJ016: WT strain; HL128: MD mutant. Data are representative of three independent experiments. (TIFF 989 kb

Cytotoxicity of selected seven compounds in NSCLC cell lines of the NCI <i>in vitro</i> 60-cell lines Drug Screen Program were on the micro-molar level.

<p>The better cytotoxicity of each compound against nine cells was highlighted.</p

Investigational structures of PARP-1 Inhibitors.

<p>Investigational structures of PARP-1 Inhibitors.</p