On the Influence of Alloy Composition on the Additive Manufacturability of Ni-Based Superalloys

The susceptibility of nickel-based superalloys to processing-induced crack formation during laser powder-bed additive manufacturing is studied. Twelve different alloys—some of existing (heritage) type but also other newly-designed ones—are considered. A strong inter-dependence of alloy composition and processability is demonstrated. Stereological procedures are developed to enable the two dominant defect types found—solidification cracks and solid-state ductility dip cracks—to be distinguished and quantified. Differential scanning calorimetry, creep stress relaxation tests at 1000 °C and measurements of tensile ductility at 800 °C are used to interpret the effects of alloy composition. A model for solid-state cracking is proposed, based on an incapacity to relax the thermal stress arising from constrained differential thermal contraction; its development is supported by experimental measurements using a constrained bar cooling test. A modified solidification cracking criterion is proposed based upon solidification range but including also a contribution from the stress relaxation effect. This work provides fundamental insights into the role of composition on the additive manufacturability of these materials.

Effects of Curcuma Longa Ethanol Extract on Isolated Guinea Pigthile Smooth Muscle in Acetylcholine Induction

Epidemiological studies show that nearly 20% of the world's population suffers from diseases related to allergies and asthma. The main compound of turmeric is curcumin has several pharmacological properties, antioxidant properties, anti-inflammatory, asthma treatment. The study aimed to determine the effects of ethanol extract Curcuma longa on the smooth muscle of the isolated guinea pigtic trachea in acetylcholine induction. This research method was experimental to observe the relationship of Curcuma longa ethanol extract (EECL) to the relaxing effects of isolated smooth muscle trachea marmot (tracheal ring chain) inserted into a bath organ filled with Kreb's physiological fluid by maintaining a temperature of 35-370C and associated with a Matlab recorder. Samples used by male guinea pigs and ethanol extract Curcuma longa (EECL). The results of the study that ethanol extract Curcuma longa has a relaxing effect on the smooth muscles of the trachea isolated from the experimental rats contracted with acetylcholine. Ethanol extract Curcuma longa has the ability not dising from theophylline 2 x 10-4 M in reducing smooth muscle contraction of insulated Cavia porcelain trachea induced by acetylcholine, acetylcholine strength without incubation contraction compared to acetylcholine with EECL incubation showed statistically different results (p <0.05). The mechanism of Curcuma longa relaxation effect on isolated guinea pig smooth muscle is mediated through inhibition of the enzyme PDE.

Relaxation Effect of Extract Ethanol Curcuma Longa on Isolated Guine Pig Trachea

Aims: Asthma is a chronic obstructive pulmonary disease which is a world health problem that is not only infected in developed countries but also in developing countries. According to the National Asthma Education and Prevention Program (NAEPP), asthma can be defined as a chronic inflammatory disorder that occurs in the airways, which involves inflammatory cells. curcumin reduces allergic airway inflammation in mice through inhibition of a specific pathway aimed at investigating the anti-inflammatory effect of curcumin in acute allergic asthma and its underlying mechanisms in mice. Study Design: This study is experimental study. Methodology: The experimental animals were divided into 2 groups, each group consisting of 4 animals. Group 1 gave theophline as a positive control group and group 2 was given extracts with concentrations (1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, 6 mg / ml, 7 mg / ml and 8 mg / ml). These animals are acclimatized for 1 (one) week with the aim of homogenizing their food and life with the same conditions so that they are considered eligible for research. Results: The ethanol extract of curcuma longa has no different ability from atropine sulfate 1 x 10-6 M in reducing the smooth muscle contraction of isolated guinea pig tracheal induced by acetylcholine, the strength of acetylcholine without incubation contraction compared to acetylcholine with EETH incubation showed statistically different results (p<0.05). Conclusion: The mechanism of the relaxing effect of curcuma longa on isolated mouse smooth muscle is mediated through inhibition of the PDE enzyme.

A Global Optimization Algorithm for Solving Linearly Constrained Quadratic Fractional Problems

This paper first proposes a new and enhanced second order cone programming relaxation using the simultaneous matrix diagonalization technique for the linearly constrained quadratic fractional programming problem. The problem has wide applications in statics, economics and signal processing. Thus, fast and effective algorithm is required. The enhanced second order cone programming relaxation improves the relaxation effect and computational efficiency compared to the classical second order cone programming relaxation. Moreover, although the bound quality of the enhanced second order cone programming relaxation is worse than that of the copositive relaxation, the computational efficiency is significantly enhanced. Then we present a global algorithm based on the branch and bound framework. Extensive numerical experiments show that the enhanced second order cone programming relaxation-based branch and bound algorithm globally solves the problem in less computing time than the copositive relaxation approach.

Revisiting the Fault Locking of the Central Himalayan Thrust with a Viscoelastic Earthquake-Cycle Deformation Model

Based on a viscoelastic earthquake-cycle deformation model, we revisit the fault locking of the central Himalayan thrust using geodetic data acquired in the past three decades. By incorporating the viscoelastic relaxation effect induced by stress buildup and release, our viscoelastic model is capable of explaining the far-field observation with similar fault locking width obtained in previous studies. Elastic models underestimate the far-field deformation and consequently underestimate the fault slip rate by attributing the far-field deformation to stable intraplate deformation. A steady-state viscosity of ∼1019 Pa·s is required for the lower crust beneath south Tibet to best fit the crustal velocity. The optimal slip rate and locking width of the central Main Himalayan Thrust are estimated to 18.8 ± 1.6 mm/a and 85 ± 2.1 km, respectively. The inferred fault locking width, along with the down-dip rupture extension of the 2015 Gorkha earthquake, agrees well with the identified mid-crustal ramp, which leads to an interpretation that the fault geometry of the central Himalayan thrust plays an important role on fault kinematics. Our results highlight that viscoelastic relaxation during the earthquake cycle should be incorporated for robust estimation of fault locking parameters and reasonable data fitting.

Measurement of the Quadratic Electro-Optic Coefficient of KTN Crystal with an Electro-Optic Modulation System in the Presence of Polar Nano-Regions

An electro-optic modulation system was adopted for measuring the quadratic electro-optic coefficient of KTN crystal. Theoretical analysis and experimental results verified the feasibility of this method. The quadratic electro-optic coefficient of a KTN crystal chip, which has a Curie temperature of 0 °C, was measured using this system in the temperature range of 2 °C to 18 °C (Tc = 0 °C). The influences of temperature, AC voltage and frequency on the quadratic electro-optic coefficient were discussed. It was found that the relaxation effect of PNRs (polar nano-regions) played an important role in the determination of the quadratic electro-optic coefficient of KTN crystal.

Structural and Impedance Analysis of 0.7Pb(Mg1/3Nb2/3)O3- 0.3PbTiO3 Ceramic

Background: Since (1-x)[Pb(Mg1/3Nb2/3)O3]-(x)PbTiO3 (PMN-PT) ceramic has high dielectric constant and piezoelectric coefficient, it has been widely investigated for profound applications in electro-optical devices, sensors, multilayer capacitors and actuators. Objectives: The aim is to study the structural and electrical properties of 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (0.7PMN-0.3PT) ceramic to understand the biphasic structural nature using Rietveld Refinement. Also, it characterises on the basis of electrical properties such as impedance and modulus to understand the relaxation process, type of conduction process as well as the role of grain and grain boundary resistance in the material. Methods: 0.7PMN-0.3PT is synthesised by mixed oxide method using PbO, MgO, Nb2O5 and TiO2 as precursor materials. Results: The XRD data reveals the biphasic structure of tetragonal phase with the space group of P4mm and monoclinic phase with the space group of Pm. The complex impedance analysis clearly represents the effect of grain on the overall resistance and departs from normal Debye type behaviour. Also, the resistance is found to decrease with temperature, thereby confirming the semiconducting nature of the sample. The presence of long as well as short-range mobility of charge carriers is confirmed from the modulus and impedance analysis. The influence of long-range motion is observed at high temperature and of short-range motion at low temperatures. Conclusion: XRD analysis confirmed the biphasic structure of M+T phase. The frequency-dependent modulus and impedance spectroscopy show the presence of a relaxation effect in the ceramic which is found to increase with temperature. The Nyquist plot shows that the resistance is decreased with temperature, thereby confirming the NTCR behaviour in the studied sample.

Comparative Analysis on Seismicity and Stress Triggering of Strong Earthquakes Sequence in Central Tibet

The Central Tibet constitutes part of the central part of Qinghai-Tibetan Plateau, which is one of the highest seismic activity areas in China. This paper discussed the regularity of seismic activity in this area. Based on a stratified viscoelastic earth model, we calculated the Coulomb stress changes imparted from the 4 strong earthquakes (M≥6.3) the Bengco - southeastern piedmont of Nyainqentanglha mountain fault zone in this region. The result shows that the study area may enter a new active period from 2020. There was a trigger between strong earthquakes (M≥6.3) on the Bengco fault - southeastern piedmont of Nyainqentanglha mountain fault zone. The post-seismic viscous relaxation effect of a strong earthquake had a significant impact on subsequent earthquakes(M≥6.3). In future 100 years, the Coulomb stress loading is more than 1.0 MPa in northwest section of Bengco fault and central of Nimu segment of southeastern piedmont of Nyainqentanglha mountain fault, thence strong earthquakes may occur in this two fault segments. The maximum magnitude of the earthquake will be M6.7 in the future 100 years.