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In this study, a 2D two-color pyrometer was developed to measure the cathode surface temperature distribution of a high-power hydrogen magnetoplasmadynamic thruster. The developed measurement system consists of an object lens, a beam splitter, bandpass filters, and two cameras. Wavelengths of 950 and 980 nm were selected to achieve a high signal-to-noise ratio by reducing the effects of plasma radiation. The cathode temperature distribution was measured in a discharge current range of 6–13 kA during approximately 1 ms quasi-steady operation. A spot-like high-temperature region over 3000 K and an overall low temperature were observed at low discharge currents. The overall cathode tip region was heated to approximately 2800 K at high discharge currents. The temperature distribution with high temperature only near the cathode tip was measured during quasi-steady operation, the duration of which is shorter than the duration of thermal conduction. These results show that the discharge current distribution near the cathode is stable during the time scale of sub-milliseconds. We confirmed that this temperature distribution remains constant during a 1 ms duty cycle through cathode temperature measurements at each operation time with a 0.2 ms exposure time. The measurement error was approximately 10% of the calculated temperature; a cross-check was performed utilizing near-infrared spectrum measurements. [ABSTRACT FROM AUTHOR]

In this study, the critical conditions of diffracted detonation waves expressed in terms of reflection point distances in Kawasaki and Kasahara (2020) were investigated for a wider range of fuel-oxidizer mixtures. In H 2 /O 2 , C 2 H 2 /O 2 , C 2 H 4 /O 2 , C 2 H 6 /O 2 , C 3 H 6 /O 2 , C 2 H 6 /N 2 O, and C 3 H 6 /N 2 O mixtures, these mixtures are used to measure the reflection point distance through the modification of the initial pressure and equivalence ratio of the mixture at room temperature. Moreover, the critical ideal reflection point distance divided by the channel width, which this dimensionless parameter was identified in the critical condition region of detonation diffraction. The results revealed that this region was in the range of 3.8 ± 0.8 for all investigated mixtures even though the equivalence ratio varied. The parameter l r,i p 0 is the product of the ideal reflection point distance and the initial pressure, which is proportional to the energy (work) per unit area required for re-initiation. The larger the product of the reflection point distance and the initial pressure, the more difficult the mixture is to re-initiate, and the inverse of this parameter represents the ease of re-initiation, which can be considered an index of detonability. Detonability, which is the objective of clarification in this study, was found to have the order C 2 H 2 /O 2 > C 2 H 4 /O 2 > C 3 H 6 /O 2 > C 2 H 6 /O 2 > H 2 /O 2 in the vicinity of the stoichiometric ratio, which is similar to the case using Matsui and Lee's critical initiation energy. [ABSTRACT FROM AUTHOR]

Rice consumption is a major source of arsenic for Asian populations. Arsenic is present in rice grain both as inorganic arsenic and as dimethylarsinic acid (DMA). It is unclear whether DMA in rice is taken up from the soil or synthesized in planta. We investigated the effect of DMA, methylarsonic acid (MMA) and arsenite amendment on arsenic speciation in rice grain grown in soil and in solution culture. We also investigated the methylation of arsenic in solution culture under suppression of bacterial activity. When rice was grown under flooded conditions after the heading stage, DMA amendment to the soil resulted in higher DMA concentration in brown rice and rice straw. In the solution culture, not only DMA amendment but also MMA or arsenite amendment increased the DMA concentration in brown rice and rice straw. DMA was detected in the solution amended by MMA or arsenite with young rice plants. When the solution included the antibacterial agent chloramphenicol, DMA concentration in the solution decreased dramatically. When only the soil was incubated with MMA or arsenite, only a slight amount of DMA was detected in the soil. These results suggest that rice rhizosphere associated bacteria would be involved in the formation of DMA in brown rice. [ABSTRACT FROM AUTHOR]

Rice consumption is a major source of cadmium and arsenic for the population of Asia. We investigated the effects of water management in rice paddy on levels of cadmium and arsenic in Japanese rice grains. Flooding increased arsenic concentrations in rice grains, whereas aerobic treatment increased the concentration of cadmium. Flooding for 3 weeks before and after heading was most effective in reducing grain cadmium concentrations, but this treatment increased the arsenic concentration considerably, whereas aerobic treatment during the same period was effective in reducing arsenic concentrations but increased the cadmium concentration markedly. Flooding treatment after heading was found to be more effective than flooding treatment before heading in reducing rice grain cadmium without a concomitant increase in total arsenic levels, although it increased inorganic arsenic levels. Concentrations of dimethylarsinic acid (DMA) in grain were very low under aerobic conditions but increased under flooded conditions. DMA accounted for 3-52% of the total arsenic concentration in grain grown in soil with a lower arsenic concentration and 10-80% in soil with a higher arsenic concentration. A possible explanation for the accumulation of DMA in rice grains is that DMA translocates from shoots/roots to the grains more readily than does inorganic arsenic. [ABSTRACT FROM AUTHOR]

Abstract: Surfactantless, hydrophilic, slightly disordered, crystalline, multiwalled carbon nanotubes (CNTs) were successfully prepared and then homogeneously and individually incorporated in an α-alumina ceramic by a recently established powder technology to investigate their load-carrying and reinforcing capabilities. As predicted, considerable structural reinforcement was obtained after spark plasma sintering, and microstructural characterizations can experimentally prove the effectiveness of the ability of these CNTs to reinforce the alumina ceramic matrix. Reinforcement mechanisms are thoroughly discussed in terms of microstructural characterizations. [Copyright &y& Elsevier]

Heteroaggregation is employed in a controlled way to the mass-production of individually alumina-decorated multi-walled carbon nanotubes (CNTs) with optimized and controlled compositions, with the aim of obtaining reinforced homogeneously dispersed CNT–alumina matrix nanocomposite after spark plasma sintering. The homogeneous composites can only be obtained for CNT concentrations in the range 2.4–16vol.%. Irreversibility of decoration is examined, and homogeneity of the composite is further investigated, based on supernatant transparency proposed in our approach. [Copyright &y& Elsevier]

Abstract: The objective of this research was to study heat insulation performance and fracture behavior of thermal barrier-type functionally graded material (FGM) coatings under high heat flux. The FGM coatings with thicknesses varying from 0.75 to 2.1 mm were designed and deposited onto a steel substrate by plasma spraying. With the high heat flux of 0.68 MW m−2, the thickest specimen exhibits a high surface temperature of 1690 °C and the corresponding temperature difference between the top surface and the bottom surface of the coating is high up to 760 °C. The results of thermal cycling test with a surface temperature of 1400 °C (during heating) showed that there existed a great difference in fracture location between different specimens. Fracture behavior of the coatings at surface temperatures of 1500, 1600 and 1700 °C was also investigated. The coating thickness and surface temperature were found to influence the number and the length of cracks. The specimen with the coating thickness of 1.1 mm is the most susceptible to local spallation at the top ceramic coat, while the thickest FGM coating is the most susceptible to cracking at the interface close to the bond coat. Heating time also had an effect on cracking behavior. These results provided some necessary information for appropriate design of FGM coatings to sustain higher temperatures and gradients than those in today''s applications. [Copyright &y& Elsevier]

Examines the impact of megakaryocytic polyploidization of human hematopoietic cells on AIM-1 protein kinase expression. Occurrence of DNA replication in the absence of cell division in megakaryopoiesis; Function of AIM-1 downregulation in abortive mitosis and polyploid formation; Regulation of cell growth and differentiation.

We reported the fabrication of terahertz photonic crystals by three-dimensional (3D) particle manipulation assembly. Our method, which is based on pick-and-place manipulation and interparticle laser welding, enabled accurate assembling of an arbitrary 3D structure, regardless of particle polydispersity. By using this method, we fabricated a diamond crystal from ZrO2/polyethylene composite particles (diameter of 400 μm). The obtained crystal exhibited a photonic stop gap in the <111> direction; this result was in good agreement with the theoretical result, suggesting that the crystal has a full photonic bandgap at around 0.2 THz. [ABSTRACT FROM AUTHOR]

Linking peace to tourism has led to key questions in the academic literature. Is tourism a generator of peace or simply its beneficiary? Can tourism be a social force or is it merely an industry? What kind of pedagogical principles can tourism utilise to promote learning for peace? This article offers a case study of Peace Boat, a Japan-based non-government organisation that contributes to human rights literacy and peace to reflect on some of these critical questions. It is based on a qualitative and collaborative research partnership that harnesses the power of stories of peace encounters to better understand the practices, pedagogies and potentials of peace tourism. We argue that when we utilise peace studies' concepts such as "positive and negative peace" and "peace with justice", we illuminate how dialogue in contested spaces is core to peace through tourism approaches. This study reveals a radical pedagogy and enables a more reflexive approach to reclaiming tourism in the interests of securing sustainability, human rights, justice and peace. In analysing the work of Peace Boat through its global voyages, we show how it fosters global solidarity, providing evidence that tourism can indeed contribute to sowing the seeds for global peace. [ABSTRACT FROM AUTHOR]

A high operating frequency of a pulse detonation engine is required to increase the thrust-to-engine weight ratio or thrust density. The semi-valveless pulse detonation cycle (PDC) proposed by Matsuoka et al. (2017) can achieve a high operating frequency exceeding several kilohertz. For achieving a higher operating frequency close to the upper limit of gas dynamics, it is necessary to minimize the process in which the buffer layer is applied to avoid self-ignition of the detonable mixture. Experiments were conducted, and a one-dimensional numerical model was developed to investigate the minimum thickness of the buffer layer and the required duration for the stable PDC operation. Ethylene was used as a fuel and pure oxygen as an oxidizer. The total length of two combustors with an inner diameter of 10 mm was 40 and 80 mm. Therefore, the thickness of the buffer layer of approximately 20 mm was suggested for the stable PDC operation. This result indicated that 10% of the duration of one PDC was required to prevent self-ignition (SI). In the failed PDC, the early and late SI were confirmed. Interestingly, high-frequency PDC operation with a short combustor can suppress late SI and results in a higher success rate with the same thickness of the buffer layer. Furthermore, a stable PDC operation of a 1916 Hz with a combustor with a total length of 40 mm was demonstrated. [ABSTRACT FROM AUTHOR]

To analyze non-ideal phenomena, such as burned gas backflow and non-detonation combustion, which affect the rotating detonation wave Mach number, simultaneous self-luminous visualization, time-averaged static pressure, fluctuating pressure, and thrust measurements with gaseous ethylene and oxygen were performed. Consequently, by doubling the number density of the fuel injectors, the hydrodynamic blockage ratio at the oxidizer inlet increased approximately 1.7-fold under the same oxidizer inlet area conditions. This may be attributed to the increase in the detonation propagation Mach number owing to the enhanced mixing of fuel and oxidizer. The relationship between the parasitic combustion fraction in front of the rotating detonation wave and the Mach number was also investigated by using a distributed heat release model. Consequently, it was suggested that experimental Mach number decreased from approximately 4.1 to 2.8 with increase in a mixture mass flux, and the theoretical detonation wave propagation Mach number was 7.3. • Mach number of rotating detonation wave was experimentally estimated. • Hydrodynamic blockage ratio increased with number density of fuel injectors. • Propagation speed of detonation wave increased with mixture mass flux. • Fluctuating pressure ratio decreased with increase in mixture mass flux. • The Mach number decreased from 4.1 to 2.8 with increase in mixture mass flux. [ABSTRACT FROM AUTHOR]

The defect-type evolution and gradual increase in nanodefects in the outer walls of multiwalled carbon nanotubes (MWCNTs) in a chemically oxidizing environment were thoroughly investigated using a mixture of sulfuric acid (H2SO4) and nitric acid (HNO3). A fairly low temperature of 323K was employed for the acid treatment, and this limited the reaction rate to provide a mild acidic environment for gradual chemical oxidation compared to commonly used treatment conditions. High-resolution transmission electron microscopy (HRTEM) observations clearly demonstrated the formation of groove-type defects in the outer walls of MWCNTs in the early period around 0.5-3h, followed by a morphological change into circumference-type defects and further into unzipped graphene nanoribbons. A unique parabolic variation in the intensity ratio of D and G bands (ID/IG) was observed. This observation supports the gradual oxidation of graphitic walls with increasing acid treatment time and corresponds well with the formation and evolution of nanodefects. Herein, the appropriate acid treatment time that would result in an effective number of nanodefects via suitable carboxyl functionalization, providing preferential nanocarbide sites for interfacial improvement as well as uniform dispersibility of MWCNTs, has been discussed. [ABSTRACT FROM AUTHOR]

Liquid propellants are commonly used in rocket engines due to their high energy density. In this study, we focused on the use of liquid ethanol and liquid nitrous oxide as propellants in a cylindrical rotating detonation engine (RDE) for practical applications, and examined the effects of various conditions on the bipropellant RDE performance. We varied the vapor quality of nitrous oxide in a mixture of liquid and gaseous nitrous oxide due to the flash boiling. In addition, we varied the liquid ethanol temperature, the injector stiffness, and momentum angle of the propellant. We then analyzed the effects of these changes on the propagation mode of the RDE under atmospheric pressure conditions. The results showed that a rotating detonation wave was observed under the combination of high vapor quality of nitrous oxide, high injector stiffness, high liquid ethanol temperature, and high momentum angle. The propagation velocity was obtained as 73∼83 % of the Chapman-Jouguet velocity. Long-duration combustion tests were also conducted, and the internal combustion structure was confirmed from the erosion of the carbon-carbon (C/C) composite material. The detonation wave was considered to propagate near the bottom of the RDE with liquid propellants from the erosion heights of the C/C composite. The erosion height was confirmed to be consistent with the fill height calculated using the sound speed of the nitrous oxide. In addition, characteristic exhaust velocity efficiencies of more than 85 % were achieved in all combustion tests. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have a remarkable load-bearing ability. Recently, however, multi-walled CNTs (MWCNTs) have been shown to possess dramatically higher load-bearing ability when intimately embedded in an oxide ceramic .Al2O3/, because the load could be transferred not to only their outermost walls but also their generally unloaded inner walls via the strong interwall shear resistance originating from residual compressive stresses. This phenomenon is characterized by an uncommon, highly energy-dissipating, multiwall-type failure of individual MWCNTs during hybrid fracture, with no evidence of pullout. Here, we demonstrate that this nanoscale in-MWCNT load-transfer process, at an optimized, high loading of MWCNTs (10 vol%) and in a pore-free and uniform platform, leads to unprecedented, dramatic simultaneous enhancement in strain tolerance (81%), fracture toughness (52.2%), and flexural strength (22%) of the Al2O3 ceramic matrix. The extent of toughening by this mechanism is also the highest ever reported. This unprecedented performance by using a high loading of functional MWCNTs, namely, toughening, strengthening, softening and lightening, simultaneously and at this level, has implications for many functional and structural applications. [ABSTRACT FROM AUTHOR]

Abstract: This research describes an investigation of the interfacial phases formed between aluminum (Al) and carbon nanotubes (CNT) which properties depend on the processing temperature (below, slightly above and over the melting point of Al). Al–CNT compacts were prepared by spark plasma sintering followed by heat treatment in order to observe the interface phases. The microstructures of both the as-sintered and heat-treated materials have been observed by optical, scanning and transmission electron microscopies. The amorphous Al oxide observed at the boundaries in the as-sintered material is transformed to crystalline Al oxide after the heat treatment. In addition, some of the CNTs decomposed and reacted with the Al, resulting in the formation of Al carbide which shows different size distributions depending on the heat treatment temperature. According to the results, it is possible to control the phase formed at the Al–CNT interface by controlling the process temperature and those controlled interfaces will be playing important role to the properties in a bulk materials. [Copyright &y& Elsevier]

Background: Rice is a major source of dietary intake of arsenic (As) for the populations that consume rice as a staple food. Therefore, it is necessary to reduce the As concentration in rice to avoid the potential risk to human health. In this study, the genetic diversity in As accumulation and As speciation in rice grains was investigated using a world rice core collection (WRC) comprising 69 accessions grown over a 3-year period. Moreover, quantitative trait locus (QTL) analysis was conducted to identify QTLs controlling the dimethylarsinic acid (DMA) content of rice grains. Results: There was a 3-fold difference in the grain As concentration of WRC. Concentrations of total-As, inorganic As, and DMA were significantly affected by genotype, year, and genotype-year interaction effects. Among the WRC accessions, Local Basmati and Tima ( indica type) were identified as cultivars with the lowest stable total-As and inorganic As concentrations. Using an F population derived from Padi Perak (a high-DMA accession) and Koshihikari (a low-DMA cultivar), we identified two QTLs on chromosome 6 ( qDMAs6.1 and qDMAs6.2) and one QTL on chromosome 8 ( qDMAs8) that were responsible for variations in the grain DMA concentration. Approximately 73% of total phenotypic variance in DMA was explained by the three QTLs. Conclusions: Based on the results provided, one strategy for developing rice cultivars with a low level of toxic As would be to change the proportion of organic As on the basis of a low level of total As content. [ABSTRACT FROM AUTHOR]

Abstract: The interface in multi-walled carbon nanotube (MWCNT)–metal matrix composites significantly effects the interfacial thermal diffusion characteristics vary due to the presence of an interphase. The thermal conductivities of MWCNT–copper (Cu) composites with and without amorphous impurity layers at the MWCNT–Cu interface as well as the Cu grain boundary have been studied. The measured thermal conductivities of composites containing chemically treated MWCNT with no amorphous impurity layers were much better than those containing pristine MWCNT. Interfacial and intergranular matrix amorphous layers, thought to originate from Cu oxide in Cu powders and amorphous carbon on the surface of the pristine MWCNT, were observed in the pristine MWCNT–Cu composite matrix. Interfacial amorphous layers a few nanometers thick generated at pristine MWCNT–Cu interfaces act as a thermal barrier and due to the relatively large thermal resistance of these layers the MWCNT are expected to act like elongated pores. Intergranular amorphous layers at the Cu grain boundaries also show thermal resistance, resulting in a decrease in the effective thermal conductivity of the Cu matrix. It is expected that amorphous carbon is partially removed by extended chemical treatment with sulfuric acid (H2SO4) and nitric acid (HNO3), inhibiting amorphous layer formation and resulting in an increase in thermal conductivity of the composites. Our results suggest that extended chemical treatment with H2SO4 and HNO3 is necessary not only for uniform dispersion of MWCNT in the ethanol solution, but also for preparation of clean surfaces free of amorphous carbon in the initial MWCNT for effective MWCNT–Cu composite fabrication. [Copyright &y& Elsevier]

Abstract: A hybrid structure of graphene nanoleaves attached on a carbon nanotube and rectangular graphene nanosheets (GNSs) were fabricated by means of radial followed by longitudinal unzipping of crystalline multiwalled carbon nanotubes (MWCNTs) grown by catalytic chemical vapor deposition, using a chemical method containing sulfuric acid and nitric acid. Consecutive unzipping in the radial direction and then in the longitudinal direction of a nanotube has never been reported. Our simple chemical approach will open the path to fabrication for rectangular GNSs in the hundred nanometers by few hundred nanometers scale and a broad application of MWCNTs to the novel carbon nanostructure. [Copyright &y& Elsevier]

Abstract: The effect of microstructure upon thermal expansion and sintering shrinkage in plasma-sprayed zirconia coatings was investigated by an accurate dilatometry. Cut-out samples with different microstructures were prepared from 5.8-mm-thick atmospheric plasma-sprayed (APS) and water-stabilized plasma coatings (WSP). It was quantitatively determined that the samples cut out of different thickness positions had minor differences in microstructure, and these APS samples largely differed from the WSP samples. The thermal expansion behaviors of all the samples coincided after a short annealing time despite their initial structural differences. On the other hand, all the samples showed a significant difference in sintering shrinkages with annealing at 1400°C. This result was consistent with the theoretical result calculated with Cipitria''s sintering model in terms of the relationship between shrinkage and microstructure. It was therefore demonstrated that the initial microstructure, particularly the splat thickness and the inter-splat pore height, exerts a great influence on the sinterability of plasma-sprayed coatings. [Copyright &y& Elsevier]

Abstract: The synthesis and formation mechanism of barium hexaaluminate compound (Ba-β-Al2O3) by solid-state reactions between powdered reactants of alumina (Al2O3) and barium carbonate (BaCO3) have been investigated. The processes for synthesizing Ba-β-Al2O3 phase include mechanically activated milling of Al2O3–BaCO3 powder mixtures and subsequent solid-state reactions at high temperatures. The mechanically activated milling results in a significant decrease in the decomposition temperature of BaCO3, hence promotes its reactions with Al2O3. Almost monophasic Ba-β-Al2O3 can be synthesized by 9–12h ball milling, followed by heat treatment at 1500°C for 2h. The formation of Ba-β-Al2O3 phase includes three stages: (i) decomposition of BaCO3, (ii) formation and growth of spherical BaO·Al2O3 particles, and (iii) reaction between Al2O3 and BaO·Al2O3 to form Ba-β-Al2O3 with an elongated morphology. [Copyright &y& Elsevier]

We determined the natural Cd balance in a cultivated rice paddy field in Japan. The main sources of Cd in the non-polluted paddy field were phosphorus fertilizer and precipitation (annual input of Cd, 2,000mg ha-1 and 1,020mg ha-1, respectively). These sources account for 95% of the total input of Cd (3,192mg ha-1). The actual increase of Cd in the soil was 0.0016mg kg-1, we thus consider Cd in soil increases only slightly as a result of rice culture. This study indicates that it is difficult to reduce Cd loading by irrigation water treatment in a non-polluted paddy field. This further indicates that once a field is polluted by Cd it is difficult to decrease the accumulated Cd by the ordinary cultivation of rice plants. [ABSTRACT FROM AUTHOR]

To analyze a rotating detonation cycle (RDC) with burned gas backflow, simultaneous self-luminous visualization, pressure, and thrust measurements with gaseous ethylene and oxygen were performed. Three different geometric blockage ratios (bottom-wall-surface area to cross-sectional area of combustor) were set at 89.2 , 70.2 , and 51.7 %. The fuel and oxidizer mass flow rates and equivalence ratio were constant at 20.6 g / s , 41.2 g / s , and 1.7, respectively. During the combustion test, the single detonation wave rotated at 1557, 1459, and 1353 m/s, and the propagation speed increased proportionally for the geometric blockage ratio. The estimated fuel–oxidizer–based specific impulse was in the range of 148 ± 8 s , and the impact of the geometric blockage ratio and propagation speeds on this specific impulse was not confirmed. The hydrodynamic blockage ratio of the oxidizer injector due to the detonation wave was estimated using the oxidizer plenum pressure. It was found that the hydrodynamic blockage ratio linearly decreased with an increase in the geometric blockage ratio. This important trend suggests that the RDC operation is limited in the region of the lower geometric blockage ratio. It is also predicted that a reduction in the hydrodynamic blockage ratio while maintaining the geometric blockage ratio is required for stable RDC operation and achievement of pressure gain combustion. Moreover, the whole RDC structure including the burned gas back flow successfully visualized at the frame rate of 0.5 and 1 µs. The validity of estimated hydrodynamic blockage ratio was demonstrated by comparison with the visualization experiment. It was concluded that the hydrodynamic blockage ratio was primarily determined mainly by the time scale of the burned gas backflow. [ABSTRACT FROM AUTHOR]

Despite the ultrahigh intrinsic strength of multiwalled carbon nanotube (MWCNT), the strengthening effect on ceramic matrix composite remains far from expectation mainly due to the weak load transfer between the reinforcement and ceramic matrix. With the assistance of the in situ pullout test, it is revealed that the liquid‐phase sintering (LPS) can serve as a novel strategy to achieve effective load transfer in MWCNT reinforced ceramic matrix composites. The YAlO3 formed liquid phase during spark plasma sintering of SiC composite greatly facilitates radical elastic deformation of MWCNT, leading to highly increased interfacial shear strength (IFSS) as well as interlayer shear resistance (ISR) of nested walls. The liquid phase with superior wettability can even penetrate into the defects of MWCNT, which further increases the ISR of MWCNT. Moreover, the first‐principles calculation indicates that the oxygen terminated YAlO3 phase displays much stronger bonding compared with SiC matrix, which is also responsible for the large IFSS in the composite. As a result, as high as 30% improvement of bending strength is achieved in the composite with only 3 wt% MWCNT in comparison to the monolithic ceramic, manifesting the unprecedented strengthening effect of MWCNT assisted by LPS. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (CNTs) have been employed for the first time to fabricate bulk, layered, nanostructure-controlled functionally graded (FG) alumina ceramics using a recently established powder technology. Gradual and homogeneous incorporation of the CNTs within the alumina ceramic shows promise to effectively cause in-depth gradients in microstructure, grain size and hardness. The FG concept offers the potential to successfully bridge conventional ceramics to their nanocomposites containing a high concentration of CNTs. [Copyright &y& Elsevier]

Aluminum matrix composites reinforced with carbon fibers or diamond particles have been fabricated by a powder metallurgy process and characterized for thermal management applications. Al/C composite is a nonreactive system (absence of chemical reaction between the metallic matrix and the ceramic reinforcement) due to the presence of an alumina layer on the surface of the aluminum powder particles. In order to achieve fully dense materials and to enhance the thermo-mechanical properties of the Al/C composite materials, a semi-liquid method has been carried out with the addition of a small amount of Al-Si alloys in the Al matrix. Thermal conductivity and coefficient of thermal expansion were enhanced as compared with Al/C composites without Al-Si alloys and the experimental values were close to the ones predicted by analytical models. [ABSTRACT FROM AUTHOR]

Three-dimensional artificial crystals with periodicity corresponding to terahertz wave lengths were fabricated by self-assembling monosized metal spherical particles. The metal crystals were weakly sintered to utilize them as templates. The metal templates were inverted to air spheres crystal embedded in dielectric resin though infiltration and etching. The resulting resin inverted crystals clearly presented the photonic stop gaps within terahertz wave region and the frequencies of the gaps were confirmed to agree well with calculation by plane wave expansion method. [ABSTRACT FROM AUTHOR]

Naldemedine is a peripherally acting μ‐opioid‐receptor antagonist for the treatment of opioid‐induced constipation. Two phase 1 single‐dose studies investigated the pharmacokinetics and safety of a 0.2‐mg oral dose of naldemedine in subjects with renal impairment (mild, n = 9; moderate, n = 9; severe, n = 6; and end‐stage renal disease, n = 8) or hepatic impairment (mild or moderate, n = 8 each) and demographically matched healthy subjects with normal renal and hepatic function (n = 8, both studies). Pharmacokinetic assessments indicate that dose adjustments for naldemedine are not necessary for subjects with any degree of renal impairment or for subjects with mild or moderate hepatic impairment. In subjects with renal impairment compared with healthy subjects with normal renal function, the geometric mean ratios of naldemedine area under the concentration‐time curve (AUC0‐inf) ranged from 82.8% (90%CI 69.5% to 98.6%) to 137.8% (90%CI 114.0% to 166.5%). Renal clearance decreased with reduced renal function (normal function 1.3 L/h; mild impairment 1.1 L/h; moderate impairment 1.0 L/h; severe impairment 0.5 L/h), and only 2.7% of naldemedine was removed by hemodialysis. In subjects with hepatic impairment compared with healthy subjects with normal hepatic function, the geometric mean ratio of AUC0‐inf ranged from 82.8% (90%CI 65.7% to 104.5%) to 105.2% (90%CI 83.4% to 132.6%). Naldemedine was well tolerated in both healthy subjects and subjects with renal or hepatic impairment, and reported adverse events were generally consistent with the known safety profile. [ABSTRACT FROM AUTHOR]

The multiple-ion-probe measurement method is a method to measure a propagating flame using ion probes installed on the wall surface of a combustion chamber. The dynamic behavior of the propagating flame along the wall surface can be regenerated from the dataset of flame signals from individual ion probes. Although this method only captures flames near the wall surface, the flame propagation behavior can be indirectly visualized. Because this method can attain very high temporal resolution, it can provide precise measurements of high-speed phenomena such as knocking in spark-ignition engines and detonation in detonation combustors. This study aimed to investigate the ability of a developed 64-channel multiple-ion-probe measurement system to characterize a propagating flame. To this end, three flames with substantially different propagation velocities were measured using the proposed multiple-ion-probe measurement system. During the experiments, methane–oxygen stoichiometric mixtures diluted with different amounts of nitrogen were used. The flame propagation velocity varied within the range of several m/s for a turbulent flame to 2.4 km/s for detonation by varying the dilution ratio of nitrogen. In the case where a mixture with a nitrogen mole fraction of 0.71 was used, a phenomenon of repeating stagnation and reacceleration of the propagating flame was observed. Furthermore, the phenomenon considered to be flame quenching was also observed near the wall. In the case of no dilution (nitrogen mole fraction = 0.00), multiple-ion probes with an installation interval of 1.5 mm indicated that the velocity fluctuated within the range of −500 m/s to +2000 m/s with respect to the Chapman–Jouguet detonation velocity of 2390 m/s. Experiments involving soot foil recording conducted in parallel confirmed that this velocity fluctuation was derived from the detonation cell structure and that micro-explosions in the detonation front could be captured using the multiple-ion-probe method. [ABSTRACT FROM AUTHOR]

Metallic or ceramic micro/nanoporous materials have attracted particular attention due to some interesting structural and functional properties. There exist a variety of methods for producing porous materials by which optimized features can be reached. Spark plasma sintering (SPS) is one of these new-emerging approaches. This technique is often combined with conventional technologies and produce a variety of porous structures with tailorable microstructure and physicomechanical properties. This review addresses SPS and obtainable porous materials with nanoscale and microscale microstructural features. The processing methods, microstructural phenomena, and physicomechanical properties of these materials are discussed in some details, along with the likely future directions required for this novel field. [ABSTRACT FROM AUTHOR]

The thermal expansion behaviors of few-layered graphene (FLG)/Al composites fabricated via spark plasma sintering and hot extrusion were evaluated. We demonstrated the first example of efficiently reducing the coefficients of thermal expansion (CTEs) of Al composites by incorporating FLG. The CTE of the Al matrix decreased from 26.72 × 10−6 K−1 to 25.53 × 10−6 K−1 with incorporating of merely 0.4 vol% of FLG. Due to the detachment of FLG-Al interface at elevated temperatures, the CTEs of the composites were slightly higher than those estimated by theoretical prediction. This result was further confirmed by the presence of hysteresis phenomenon of the cyclic expansion behavior of the FLG/Al composite. Moreover, the FLG exhibited a high constraining efficiency of ∼13, being more effective at lowering the CTEs of Al composites as compared to other traditional fillers. This work could be significant for guiding the design of high-performance graphene/Al composites for thermal management applications. Image 1 • Thermal expansion behaviors of graphene/Al composites were firstly studied. • Uniform few-layer graphene (FLG)/Al composites were successfully fabricated. • Coefficients of thermal expansion (CTEs) of Al decreased efficiently with incorporating FLG. • The hysteresis of cyclic expansion behavior occurred due to interfacial detachment. • Graphene is more effective at lowering the CTEs of Al composites than traditional fillers. [ABSTRACT FROM AUTHOR]

Abstract Fabricating high-strength Al matrix composites without sacrificing their electrical conductivity is a critical issue in the design of Al-based conductors. Here, we demonstrate for the first time, an example of improving the interfacial load transfer and strength of few-layer graphene (FLG)/Al composites by an appropriate interfacial reaction. Monocrystalline Al 4 C 3 nanorods that tightly conjoined the FLG platelets with the Al matrix were produced by manipulating the sintering temperature. As revealed by transmission electron microscopy and by a shear lag model that provides a quantitative estimate of the strengthening, the Al 4 C 3 nanorods ensured an efficient load transfer at the FLG-Al interface, thereby giving rise to a considerable enhancement of strength in the composite. Moreover, the electrical conductivity is almost as high as that of pure Al, which could be a significant step toward the preparation of high-performance Al-based conductors. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract Although filled skutterudites are very promising thermoelectric (TE) materials at intermediate temperature, most of the high-performance skutterudites reported are multiple-filled materials that tend to have poor stability and machinability. Here, we successfully fabricate single-filled skutterudite based composites with uniformly dispersed β-SiC nanoparticles via cryogenic grinding and spark plasma sintering. The nanocomposites show not only increased Seebeck coefficient owing to a possible energy filtering effect, but also reduced lattice thermal conductivity through enhanced phonon scattering. A maximum ZT value of 1.42 at 850 K with greatly improved mechanical properties is achieved, which is very attractive for the application in TE devices. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract We successfully fabricated a controllable intragranular pore containing hydroxyapatite (HA) by the combination of an electric current assisted sintering and pre-heat treatment process. The microstructure and mechanical properties of the sintered HA bulk with and without intragranular pores were investigated in this study. Fully densified HA fabricated by the combination of an electric assisted sintering and pre-heat treatment process showed extremely superior mechanical properties. Meanwhile, hierarchically structured porous HA consisting of nanosized intragranular pores without macropores in the grain boundary showed dramatically decreased elastic modulus by different fracture mechanism compared with fully densified HA. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The MoSiBTiC alloy is one promising candidate for ultrahigh–temperature materials. However, it faces severe challenges in the machining of complex shapes because of its significant brittleness, high melting point, and stiffness. To overcome this challenge, we have successfully fabricated MoSiBTiC alloy parts via laser powder bed fusion (L-PBF). A combination of arc-melting and controllable high-energy ball milling (HEBM) was employed to prepare suitable MoSiBTiC powders for L-PBF. The evolution of powder morphology, constituent phases, and laser absorptivity, as well as particle size and distribution during HEBM, was investigated. Moreover, the effects of L-PBF parameters on the densification, microstructure, and mechanical performance of MoSiBTiC alloy builds were studied. A dense MoSiBTiC alloy, mainly consisting of a Mo solid-solution, Mo 5 SiB 2 , Mo 2 C, and TiC phases, was obtained at an energy density of 156 J mm−3 using the laser power of 70 W. Compared to the as-cast alloy, the L-PBF-processed MoSiBTiC alloy possessed more uniform and finer grain structures, while exhibiting a lower Vickers hardness due to the existence of internal microcracks. It was also proved that the small quantity of ZrO 2 particles from HEBM processing was uniformly imbedded in L-PBF builds. This work may offer significant guidance for designing and producing complexly shaped refractory intermetallics with unique microstructures in ultrahigh–temperature applications. Graphical abstract Image 1 Highlights • Additive manufacturing of MoSiBTiC alloy for ultrahigh–temperature material was firstly attempted. • An effective approach was developed and optimized for large-scale production of starting MoSiBTiC powders. • High-density MoSiBTiC alloy (∼99.8%) was produced via optimizing laser processing conditions. • Additive-manufactured MoSiBTiC alloy had more uniform and finer grain structures than as-cast one. [ABSTRACT FROM AUTHOR]

Abstract A novel Al 4 C 3 nanorod was synthesized through an in situ reaction between graphene oxide (GO) and Al powders during laser powder bed fusion (L-PBF). The few-layer GO sheets were prepared by a modified Hummers method and were mixed with Al powders by electrostatic self-assembly. After subsequent L-PBF processing, the GO reacted with Al atoms completely to form Al 4 C 3 nanorods that had a mean diameter of ∼140 nm and length of ∼2.3 μm, displaying a higher aspect ratio than that made by traditional powder metallurgy. Observations of high-resolution transmission electron microscopy revealed that the Al 4 C 3 was monocrystalline and intimately contacted with the Al matrix, consequently resulting in the noticeably enhanced mechanical performance of the composite. This work may offer significant guidance for designing and producing new high-specific-strength materials for structural applications. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Background and Objective: Baloxavir marboxil, a prodrug that is metabolized to baloxavir acid, suppresses viral replication by inhibiting cap-dependent endonuclease. This first-in-human phase I study evaluated the safety, tolerability, and pharmacokinetics of baloxavir marboxil/baloxavir acid in healthy Japanese volunteers (Study 1), while food effects were evaluated in a separate phase I, crossover study in healthy Japanese volunteers (Study 2).Methods: Study 1 participants were randomized to single-dose oral baloxavir marboxil (6, 20, 40, 60, or 80 mg; n = 6 per dose) or placebo (n = 10), while Study 2 participants (n = 15) received single-dose oral baloxavir marboxil 20 mg in fasted, fed, and before-meal states.Results: Baloxavir marboxil was well tolerated; there were few treatment-emergent adverse events and no serious adverse events/deaths. The mean plasma baloxavir acid concentration 24 h after single-dose (C24) oral baloxavir marboxil 6 mg was 6.92 ng/mL, exceeding the target C24 (6.85 ng/mL) estimated in nonclinical studies. In Study 1, baloxavir acid exposure demonstrated dose-proportional increases in the fasted state, with maximum plasma concentration generally attained within 3.5 h. Terminal elimination half-life ranged from 49 to 91 h. In Study 2, exposure was decreased and apparent clearance increased in the fed and before-meal states versus the fasted state; however, exposure exceeded the target C24 in all states.Conclusion: Single-dose oral baloxavir marboxil was well tolerated, had a favorable safety profile, and had favorable pharmacokinetic characteristics, including a long half-life, supporting single oral dosing. The baloxavir acid area under the plasma concentration-time curve decreased with food intake by approximately 40%. [ABSTRACT FROM AUTHOR]

The authors of article “Genetic diversity of arsenic accumulation in rice and QTL analysis of methylated arsenic in rice grains” (Kuramata et al. 2013) would like to note that the original version of the article online unfortunately contains the following errors: [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) has attracted considerable attention as an advanced method for the fabrication of biomedical devices. However, SLM-manufactured parts easily accumulate large amounts of residual stress due to rapid heating and cooling, which negatively affects their mechanical properties. In this study, Co–Cr–Mo alloy specimens were fabricated by SLM and then heat-treated at various temperatures (750, 900, 1050, or 1150 °C) to relieve the residual stress and improve their mechanical properties. The alloy microstructure was analyzed via confocal laser scanning microscopy, scanning electron microscopy combined with energy dispersive X-ray spectroscopy, electron backscattered diffraction, and X-ray diffraction techniques, whereas the mechanical properties of the produced specimens were evaluated by tensile and Vickers hardness tests. The results showed that increasing the heat-treatment temperature from 750 °C to 1150 °C increased the ductility of the alloy and decreased its 0.2% offset yield strength and Vickers hardness. Both γ and ε phases formed in all heat-treated specimens, and the volume fraction of the ε phase decreased with increasing heat-treatment temperature. After the specimens were heated to 750–1050 °C, a recovery process was initiated, which proceeded as the temperature increased; however, the residual stress in the studied specimens was not sufficiently relieved. In contrast, after heating to 1150 °C, the formation of equiaxed grains and the drastic relief of the residual stress were observed simultaneously, accompanied by an increase in the elongation of the specimen and a decrease in its strength (as compared to those of the other heat-treated specimens), indicating that the specimen completely recrystallized and that the residual stress was the driving force of this recrystallization. Thus, heat-treating at 1150 °C for 6 h is an effective method for eliminating the residual stress, leading to a homogenized microstructure and satisfactory ductility. [ABSTRACT FROM AUTHOR]

A strategy utilizing carbon nanotubes (CNTs) was put forward to synthesize in situ TiC/Mo-based composites via laser powder bed fusion (laser PBF). The functionalized CNTs were dispersed with MoTiAl powders under electrostatic attraction by heteroagglomeration. During laser PBF, individual CNTs reacted with Ti elements and were completely transformed into monocrystalline TiC. Those TiC reinforcements were homogeneously dispersed and intimately contacted the matrix, giving rise to the morphological evolution of a MoTiAl matrix from the nearly columnar to fine equiaxed grains as well as improved mechanical performance. Our finding offers significant guidance for designing and producing advanced Mo-based composites in the application of heat-resistant materials. [ABSTRACT FROM AUTHOR]

Periodic lines with intervals ranging from ∼220 μm down to ∼27 μm were fabricated on the surface of Zr 55 Cu 30 Al 10 Ni 5 metallic glass ribbon and disk samples by laser irradiation. The X-ray diffraction results indicated that both oxides (monoclinic ZrO 2 , tetragonal ZrO 2 ) and crystallites (Cu 10 Zr 7 , NiZr 2 ) existed together with the amorphous phase on the surface of the laser-patterned metallic glass samples. The energy-dispersive X-ray spectroscopy of a cross section of a disk sample clearly showed that high amounts of aluminum (292% of the nominal composition) and oxygen were present in the laser-irradiated area, suggesting that Al 2 O 3 formed on the surface of the laser-irradiated region. Reflective diffraction spots were observed from the fine grids with a grating period of ∼27 μm, indicating the excellent periodicity and accuracy of the pattern in two dimensions on the surface of the metallic glass substrates. Calculation of the grating period using Bragg's law confirmed that the spots originated from the periodic patterns of the laser-irradiated lines. Along the lines, pairs of ridges and hollows with a height/depth of ∼0.5 μm were observed; such specific morphology generated the diffraction spots as a reflective grating. We observed structural color gradation from the periodic fine grids under a fluorescent light. The present study showed that it is possible to prepare optical gratings on the surface of metallic glasses by laser irradiation more cheaply and easily than by conventional imprinting. [ABSTRACT FROM AUTHOR]

Titanium sub-oxides of Magnéli phase are considered as earth-abundant, non-toxic materials for thermoelectric application at high temperature, but very limited investigation has been reported mainly owing to the difficulty lying in obtaining monophasic material. Herein we describe a facile strategy to prepare monophasic Ti 9 O 17 and Ti 4 O 7 powder, in which the single Ti 9 O 17 phase is obtained for the first time. After spark plasma sintering, the thermoelectric properties of monophasic Ti 9 O 17 and Ti 4 O 7 ceramics are studied comparatively. Despite the one magnitude lower electrical conductivity, Ti 9 O 17 shows higher power factor compared with Ti 4 O 7 due to the large Seebeck coefficient. Moreover, with the low electronic thermal conductivity, sub-micron scaled grain size and nano-scaled crystallographic shear plane, the Ti 9 O 17 ceramic exhibits even lower thermal conductivity compared to Ti 4 O 7 , leading to a ZT of 0.16 at 764 K, which is the best thermoelectric performance among reported Magnéli phases. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (PBF) offers many technological opportunities for producing high-performance composite parts with tailored structures. However, fabrication of suitable composite powders possessing homogenous dispersion, good flowability, suitable particle size and distribution is a prerequisite and main challenge currently faced. In this study, a novel strategy was developed to prepare nanoceramic/metal powders by using acid-treated carbon nanotubes (ATCNTs) as an agent. In detail, a 3 wt% ATCNT/Al 2 O 3 colloid, in which the negatively-charged ATCNTs were partially covered with positively-charged Al 2 O 3 nanoparticles under electrostatic attraction, was obtained by heteroagglomeration; subsequently, the uncovered surface areas of ATCNTs were intimately bonded to the positively-charged MoTiAl powders during their mixing. This ATCNT bridging made individual Al 2 O 3 uniformly wrap on the surface of MoTiAl without aggregation. The Al 2 O 3 -coated MoTiAl powders remained similar in shape, particle size, and distribution to uncoated ones, simultaneously showing higher laser absorptivity due to an increased surface roughness. The PBF-processed Al 2 O 3 -ATCNT/MoTiAl composite was dense, in which Al 2 O 3 nanoparticles were homogenously dispersed and intimately contacted with MoTiAl, giving rise to an increase in the hardness of the matrix. [ABSTRACT FROM AUTHOR]

Periodic lines, approximately 15-μm-wide and separated by several hundred micrometers, were prepared on the surface of Zr 55 Cu 30 Al 10 Ni 5 metallic glass by scanning a focused laser beam across the samples in air. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) suggested that the lines produced by the focused laser beam consisted of localized metal oxides (tetragonal ZrO 2 , monoclinic ZrO 2 ) and crystallites (Cu 10 Zr 7 ), which was in contrast to the amorphous substrate. The electron backscatter diffraction (EBSD) also confirmed the successful patterning of the lines which was mainly composed of the fine ZrO 2 grains. The energy dispersive X-ray spectroscopy (EDS) mapping clearly exhibits that high amounts of zirconium (161% of the nominal composition) as well as oxygen (58.9%) and a certain amount of aluminum (80% of the nominal composition) were presented in the beam-scanned area. The Auger electron spectroscopy (AES) was also conducted to see the atomic percentage from the top surface to the depth direction and showed that the created oxides were thermally stable and therefore oxidization cannot proceed with increasing the number of laser scan. We confirmed that the laser irradiation method has a large degree of freedom for designing patterns, such as interdigital, dots, and letters because of the precise control over the scanning stage. [ABSTRACT FROM AUTHOR]

Iron-ferrite composites fabricated by powder metallurgy processes were studied for electromagnetic and large band microwave absorption applications. The sintering behavior of such composites is not well-understood, and these materials have been found to lose their magnetic properties or mechanical properties. Different systems of Fe/NiZn ferrite composites were investigated in order to better understand the chemical reactions that occur between oxide spinel and iron particles during the fabrication process. Three different systems, two models and one reference material were studied to analyze the chemical reactions in the aforementioned fabrication process. The first model consisted of iron films deposited by Physical Vapor Deposition (PVD) onto an NiZn-ferrite substrate. The reference material was made of a mixture of hot pressed iron and ferrite powders. In the second model, a SiO 2 layer was deposited by PVD onto the NiZn-ferrite substrate, followed by iron deposition by PVD to study the role of SiO 2 as a diffusion barrier. The materials were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), dilatometry, electron probe microscopy analysis (EPMA) and X-ray diffraction (XRD). For the Fe/NiZn ferrite systems, the experimental results showed (i) an oxido-reduction reaction above 600 °C that produced FeO and Fe x Ni 1-x phases and (ii) a diffusion process of Ni and Zn. The combination of diffusion and oxido-reduction reaction induced the total consumption of the initial phase and a considerable decrease in magnetic properties. By adding a silica layer between the iron and ferrite layers, the redox interfacial reaction and iron diffusion were prevented at temperatures up to 800 °C. [ABSTRACT FROM AUTHOR]

The technological and industrial needs for development of fully dense nanocomposites have led to significant advances in spark plasma sintering (SPS) technique and its enhanced forms. This technique has opened up a new prospect over carbon nanotube (CNT)-metal matrix nanocomposites (MMNCs) with superior physical or mechanical characteristics. To date, a large number of authentic papers have been published over this ongoing field, but have not been comprehensively reviewed. The pertinent research works cover some significant aspects of CNT-MMNCs requiring a concise review on (i) the potential phase transformations of pure CNTs and microstructure evolution; (ii) the novel approaches for uniform dispersion of CNTs inside the metallic matrices including Cu, Al, Ag, Ni, Ti, Mg, and Fe; and (iii) recent improvements in mechanical, thermal, electrical, biological, and tribological properties of CNT-MMNCs. The present review paper strives to scrutinize the aforementioned topics and provide a broad overview of the unsolved challenges and suggested solutions for them. [ABSTRACT FROM AUTHOR]

The thermal expansion response of multi-walled carbon nanotube (MWCNT) reinforced Al matrix composites was employed to discuss the improvement of the load transfer at the interface between the MWCNTs and the Al matrix. An aluminum carbide (Al 4 C 3 ) nanostructure at the end of the MWCNTs, incorporated in the Al matrix, was produced by appropriate heat-treatment. The stress contrast around the Al 4 C 3 observed in the high-resolution transmission electron microscopy (HRTEM) image revealed the evidence of a trace of friction, which would lead to the enhancement of the anchor effect from the Al matrix. This anchor effect of Al 4 C 3 may hinder the local interfacial slippage and constrain the deformation of the Al matrix. As a result, the thermal expansion behavior became linear and reversible under cyclic thermal load. It is concluded that the formation of Al 4 C 3 could effectively enhance the load transfer in MWCNT/Al composites. The yield strength of MWCNT/Al composites was substantially increased under the appropriate quantity of Al 4 C 3 produced at the MWCNT-Al interface by precisely controlled heat-treatment. [ABSTRACT FROM AUTHOR]