Solid oxide electrolysis: Concluding remarks

Renewable energy resources such as solar energy, wind energy, hydropower or geothermal energy have attracted significant attention in recent years. Renewable energy sources have to match supply with demand, therefore it is essential that energy storage devices (e.g., secondary batteries) are developed. However, secondary batteries are accompanied with critical problems such as high cost for the limited energy storage capacity and loss of charge over time. Energy storage in the form of chemical species, such as H-2 or CO2, have no constraints on energy storage capacity and will also be essential. When plentiful renewable energy exists, for example, it could be used to convert H2O into hydrogen via water electrolysis. Also, renewable energy resources could be used to reduce CO2 into CO and recycle CO2 and H2O into sustainable hydrocarbon fuels in solid oxide electrolysis (SOE).open0

Properties of Non-Sintered Cement Pastes Immersed in Sea Waters at Different Temperatures for Binders Mixed with Different Ratios

This paper presents an investigation of the mechanical properties on non-sintered cement pastes immersed in sea waters at three differenttemperatures. The non-sintered cement pastes were synthesized using blended binder(Class F fly ash; FA and ground granulated blast furnace slag;GGBFS) and alkali activator(sodium hydroxide and sodium silicate). Binders were prepared by mixing the FA and GGBFS in different blend weightratios of 6:4, 7:3 and 8:2. The alkali activators were used 5wt% of blended binder, respectively. Calcium carbonate was used as an chemical additive. The compressive strength, bulk density and absorption of alkali-activated FA-GGBFS blends pastes were measured at 3 and 28 days after immersedin sea waters at three different temperatures(5??C, 15??C and 25??C). The XRD and SEM tests of the pastes were conducted at 28 days. Water-solublechloride(free chloride) and acid-soluble chloride(total chloride) contents in the pastes were also measured after 28 days immersion in sea water. Theexperimental results showed that increasing the content of FA in alkali-activated FA-GGBFS blends pastes immersed in sea water increases theabsorption, water-soluble chloride content and acid-soluble chloride content, and reduces the compressive strength and bulk density. And it was foundthat there was a variation of strength change for the alkali-activated FA-GGBFS blends pastes immersed in sea waters at three different temperaturesthat depends on the blending ratio of FA and GGBFS.clos

A Passivity-based Nonlinear Admittance Control with Application to Powered Upper-limb Control under Unknown Environmental Interactions

This paper presents an admittance controller based on the passivity theory for a powered upper-limb exoskeleton robot which is governed by the nonlinear equation of motion. Passivity allows us to include a human operator and environmental interaction in the control loop. The robot interacts with the human operator via F/T sensor and interacts with the environment mainly via end-effectors. Although the environmental interaction cannot be detected by any sensors (hence unknown), passivity allows us to have natural interaction. An analysis shows that the behavior of the actual system mimics that of a nominal model as the control gain goes to infinity, which implies that the proposed approach is an admittance controller. However, because the control gain cannot grow infinitely in practice, the performance limitation according to the achievable control gain is also analyzed. The result of this analysis indicates that the performance in the sense of infinite norm increases linearly with the control gain. In the experiments, the proposed properties were verified using 1 degree-of-freedom testbench, and an actual powered upper-limb exoskeleton was used to lift and maneuver the unknown payload.Comment: Accepted in IEEE/ASME Transactions on Mechatronics (T-MECH

Ductile Fracture Simulation of Full-scale Circumferential Cracked Pipes: (II) Stainless Steel

AbstractThis paper reports ductile fracture simulation of full-scale circumferentially cracked pipes using finite element (FE) damage analysis. In the structural integrity, without experimental investigations or with few ones, it is not an easy task to properly evaluate the crack initiation and crack propagation of large-scale components with a crack-like defect. Unfortunately, from an economic perspective, performing experiments of large-scale components would be consequently unfavorable. For these reasons, ductile fracture simulation using FE damage analysis to predict crack behavior is one efficient way to replace the test procedures. In order to simulate ductile tearing of large-scale cracked pipes, element-size-dependent critical damage model based on the stress-modified fracture strain model is proposed. To evaluate fracture behavior of full-scale cracked pipes, tensile and C(T) specimens are calibrated by FE analysis technique. Tensile properties and fracture toughness of stainless steel at 288oC are taken from Battelle Pipe Fracture Encyclopedia. After calibrations, simulated results of the full-scale pipes with a circumferential crack are compared with test data to validate the proposed method

Boundary integral equation method for resonances in gradient index cavities designed by conformal transformation optics

In the case of two-dimensional gradient index cavities designed by the conformal transformation optics, we propose a boundary integral equation method for the calculation of resonant mode functions by employing a fictitious space which is reciprocally equivalent to the physical space. Using the Green's function of the interior region of the uniform index cavity in the fictitious space, resonant mode functions and their far-field distributions in the physical space can be obtained. As a verification, resonant modes in lima\c{c}on-shaped transformation cavities were calculated and mode patterns and far-field intensity distributions were compared with those of the same modes obtained from the finite element method.Comment: 13 pages, 6 figure

The Bilirubin Level is Negatively Correlated with the Incidence of Hypertension in Normotensive Korean Population

Reactive oxygen species have been known to be an important factor in the pathogenesis of hypertension. Bilirubin, one of the metabolites of heme degraded by heme oxygenase, is a potent anti-oxidant. We verified the effect of serum bilirubin level on the incidence of hypertension in normotensive subjects. We grouped 1,208 normotensive subjects by the criterion of the highest quintile value of serum bilirubin, 1.1 mg/dL. The incidence of hypertension was higher in group 1 with bilirubin less than 1.1 mg/dL than in group 2 with bilirubin 1.1 mg/dL or more (186/908 vs. 43/300, p=0.018). The relative risk for hypertension was 0.71 (95% confidence interval, 0.51-0.99), p=0.048 in group 2 compared to group 1 by Cox's proportional hazard model. Among the groups stratified by gender, smoking, and liver function status, the group 2 showed a lower risk of hypertension in females and in non-smokers. In conclusion, a mild increase within the physiological range of serum bilirubin concentration was negatively correlated with the incidence of hypertension. The effect of bilirubin on the development of hypertension was more evident in females and in non-smokers

Curcumin induces stabilization of Nrf2 protein through Keap1 cysteine modification

The present study was aimed to investigate the effects of curcumin, a representative chemopreventive phytochemical with pronounced antioxidant and anti-inflammatory properties, on activation of Nrf2 and expression of its target protein heme oxygenase-1 (HO-1) in mouse skin in vivo and in cultured murine epidermal cells. Treatment of mouse epidermal JB6 cells with curcumin resulted in the induction of HO-1 expression, and this was abrogated in cells transiently transfected with Nrf2 siRNA. While curcumin treatment increased protein expression of Nrf2, it did not alter the steady-state level of the Nrf2 mRNA transcript. Treatment of cells with curcumin stabilized Nrf2 by inhibiting ubiquitination and subsequent 26S proteasomal degradation of this transcription factor. Tetrahydrocurcumin, a non-electrophilic analogue of curcumin that lacks the alpha,beta-unsaturated carbonyl group, failed to induce HO-1 expression as well as nuclear translocation of Nrf2 and its binding to the antioxidant/electrophile response elements. Cells transfected with a mutant Keap1 protein in which cysteine 151 (Cys151) is replaced by serine exhibited marked reduction in curcumin-induced Nrf2 transactivation. Mass spectrometric analysis revealed that curcumin binds to Keap1 Cys151, supporting that this amino acid is a critical target for curcumin modification of Keap1, which facilitates the liberation of Nrf2. Thus, it is likely that the alpha,beta-unsaturated carbonyl moiety of curcumin is essential for its binding to Keap1 and stabilization of Nrf2 by hampering ubiquitination and proteasomal degradation.

Graphene Q-switched Yb:KYW planar waveguide laser

A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in a 2.4-cm-long waveguide laser operating near 1027 nm. Average output powers up to 34 mW and pulse durations as short as 349 ns are achieved. The measured output beam profile, clearly exhibiting a single mode, agrees well with the theoretically calculated mode intensity distribution inside the waveguide. As the pump power is increased, the repetition rate and pulse energy increase from 191 to 607 kHz and from 7.4 to 58.6 nJ, respectively, whereas the pulse duration decreases from 2.09 μs to 349 ns

Young Malaysian Consumers’ Attitude and Intention to Imitate Korean Celebrity Endorsements

This study addressed the issue of young Malaysian consumers’ intention to imitate Korean celebrities’ endorsement in advertisements. The researchers specifically focused on the impact of Korean celebrity characteristics and the consumer’s individual characteristics on the latter’s attitude towards imitating celebrity endorsements and the consumer’s intention to imitate. 602 young Malaysian consumers in the Klang Valley participated in this study. The results pointed to celebrity characteristics namely attractiveness and trustworthiness as directly and indirectly significant, whilst credibility and expertise were directly and indirectly not significant predictors on consumer attitude toward imitating celebrity endorsements. In addition, individual characteristics namely self-satisfaction and expression of power were directly and indirectly significant predictors on consumer attitude towards imitating celebrity endorsements. There was also a significant effect on attitude towards imitating celebrity endorsements on intention to imitate. Suggestions for future research are discussed at the end of this paper

Development of IoT-Based Sensor Tag for Smart Factory

To reduce the rate of defective products and ensure the health of employees, it has become increasingly necessary to improve air quality in factories. To do so, it is important to accurately determine the air quality in the factory first. However, currently available industry-grade sensors require complex and often separate construction processes, making them difficult to use in complicated industrial sites. In order to solve such an issue, this study developed an IoT-based sensor that can collect data such as factory temperature, humidity, CO2 levels, dust, and stench. This study has also developed software to manage the IoT-based sensors, which can transmit the data via RF communication. Sensor tags were tested for basic environmental durability, including waterproof, dustproof, and vibration standards. The sensors can be connected via USB to a computer to configure its settings and access the stored data within the sensors. Unlike other existing environmental sensors, these can be easily installed anywhere as they transmit data via wireless communication. These sensors can also be installed in the factory to check the factory’s internal pollution level in real time. The application of this sensor will enable the real-time monitoring of air pollution in factories. By locating the polluted areas accurately, it will be possible to exercise distributed control over ventilation devices to prevent further spread of pollutants, while also pushing out the polluted air to maintain an optimal working environment. Future studies should develop a simulation model for determining the ideal installation location for the sensors. There also needs to be further studies in developing a distributed-controlled air-conditioning system to run empirical tests