Advanced wastewater treatment using filamentous algae in raceway ponds with underwater light

The current study evaluated nutrient removal efficiency, algae productivity, and economic feasibility related to cultivation of the filamentous algae, Hydrodictyon reticulatum, in a pilot plant-scale raceway pond with underwater light. Following the installation of an underwater light device, removal efficiencies of T-N and T-P increased by 11.0% and 12.3%, respectively. The productivity of algae also increased by 133.8% to 5.81 g/m²?d. Installation of the underwater light device increased the wastewater treatment capacity by over 3 times in the same area and enabled the removal of nutrients by over 3.5 times and removal of carbon dioxide by an additional 39 tons/yr. Estimates indicated that the cost of wastewater treatment and nutrient removal was reduced by more than 67%, while the production cost of H. reticulatum was reduced by 18% or more. Therefore, underwater light may solve issues related to the need for large sites in existing raceway ponds and enhance the economic efficiency by improving nutrient removal efficiency and productivity.     

Inventing modern taste at the Changgyeongwon Botanical Garden

The first public botanical garden of Korea, the Changgyeongwon Botanical Garden, was established for the purpose of promoting ‘taste’ in 1909 during the Japanese colonial period. This paper examines the concept of ‘taste’—‘shumi’ and ‘chwimi’—in order to show how the Changgyeongwon Botanical Garden played a role as a colonial botanical garden in Korea during the early twentieth century. At the end of the Meiji period, the concept of ‘shumi’ to acquire cultural improvement justified the Japanese authorities’ proposal to establish the botanical garden for the purpose of promoting ‘shumi’ and developing Japanese taste in Korea. In early twentieth-century Korea, the concept of ‘chwimi’ to develop knowledge, refinement and virtues, and the discussion on the roles of botanical gardens in improving ‘chwimi’, provided the foundation for the Changgyeongwon Botanical Garden to be acknowledged as a symbol of good taste or popular culture despite its Japanese colonial origin.     

Excitations of incoherent spin-waves due to spin-transfer torque

The possibility of exciting microwave oscillations in a nanomagnet by a spin-polarized current, as predicted by Slonczewski and Berger, has recently been demonstrated. This observation opens important prospects of applications in radiofrequency components. However, some unresolved inconsistencies are found when interpreting the magnetization dynamics within the coherent spin-torque model. In some cases, the telegraph noise caused by spin-currents could not be quantitatively described by that model. This has led to controversy about the need for an effective magnetic temperature model. Here we interpret the experimental results of Kiselev et al. using micromagnetic simulations. We point out the key role played by incoherent spin-wave excitation due to spin-transfer torque. The incoherence is caused by spatial inhomogeneities in local fields generating distributions of local precession frequencies. We observe telegraph noise with gigahertz frequencies at zero temperature. This is a consequence of the chaotic dynamics and is associated with transitions between attraction wells in phase space.     

Development of a detection sensor for mixed trimethylamine and ammonia gas

This study investigated the gas sensor fabricated with TiO₂ added with metal oxide and catalyst to detect the main mixed gases, usually generated when the meat begins to decay, in order to measure the change in freshness according to protein denaturation. In particular, when fish begins to decompose, TMAO (trimethylamine oxide) is transformed into TMA (trimethylamine) by enzymes to regulate the salinity in fish, which is the major cause of fishy smell. The thick-film semi-conductor gas sensor for trimethylamine and ammonia mixed gas was fabricated with WO₃–TiO₂ prepared by sol–gel and precipitation methods. The nanosized TiO₂ was mixed with WO₃ and doped with transition metals (Pt, Ru, Pd and In). Particle sizes, phases and specific surface areas of sensor materials were investigated by SEM, XRD and BET analyses. The metal-TiO₂ thick films were prepared by screen-printing method onto Al₂O₃ substrates with platinum electrode. It was shown that the highest sensitivity and selectivity of the sensor for trimethylamine and ammonia mixed gas by doping with 1 wt.%In and 15 wt.% WO₃ was reached at the optimum operating temperature of 350 °C.     

Crack Repairing in Alumina by Penetrating Glass

Through-the-thickness cracks with the depth of about 2.5 mm were introduced on the flexural specimens of alumina. Borosilicate glass was then penetrated into the cracks at 1500°C to repair them. Strength testing indicated that the cracks, once repaired, became even stronger than mother material alumina. The reason of the strengthening was discussed in terms of residual stress and the rebonding of alumina grains on crack surfaces. This investigation implies that cracks in alumina can be repaired by simply penetrating glass into them.     

Chronic and acute effects of walnuts on antioxidant capacity and nutritional status in humans: a randomized,cross-over pilot study

Background  

Compared with other common plant foods, walnuts (Juglans regia) are consistently ranked among the highest in antioxidant capacity. In vitro, walnut polyphenols inhibit plasma and LDL oxidation, while in animal models they lower biomarkers of oxidative stress and raise antioxidant capacity. A limited number of human feeding trials indicate that walnuts improve some measures of antioxidant status, but not others.     

Cooling of a heated surface with an impinging water spray

Several important parameters, such as liquid mass flux, droplet size distribution, droplet velocity, and heating target conditions (roughness and surface temperature) are involved in the industrial spray cooling heat transfer process. In this study, we investigated the effect of liquid mass flux, heating target roughness, and the droplet size on the droplet wall direct contact heat transfer in spray cooling phenomena. Three different conditions of surface roughness were investigated. The measurement of test surface temperature was performed using a non-intrusive method, i. e., using an infrared thermometer. The droplet size distribution of water spray was measured with Malvern 2600. The results indicated that the most influential parameters were the liquid mass flux and the surface roughness. The droplet size and the velocity played a less important role in the direct contact heat transfer because the interactions between droplets were very strong in a dense spray. The smooth surface showed the highest heat transfer among the surfaces tested. At high air pressure ([7] kPa), however, the degree of roughness did not affect much the heat transfer rate.     

Current-Induced Spin–Orbit Torques for Spintronic Applications

Control of magnetization in magnetic nanostructures is essential for development of spintronic devices because it governs fundamental device characteristics such as energy consumption, areal density, and operation speed. In this respect, spin–orbit torque (SOT), which originates from the spin–orbit interaction, has been widely investigated due to its efficient manipulation of the magnetization using in-plane current. SOT spearheads novel spintronic applications including high-speed magnetic memories, reconfigurable logics, and neuromorphic computing. Herein, recent advances in SOT research, highlighting the considerable benefits and challenges of SOT-based spintronic devices, are reviewed. First, the materials and structural engineering that enhances SOT efficiency are discussed. Then major experimental results for field-free SOT switching of perpendicular magnetization are summarized, which includes the introduction of an internal effective magnetic field and the generation of a distinct spin current with out-of-plane spin polarization. Finally, advanced SOT functionalities are presented, focusing on the demonstration of reconfigurable and complementary operation in spin logic devices.     

Effect of various antimicrobials on the growth kinetics of foodborne pathogens in ready-to-eat, pyeonyuk (cooked and pressed pork)

This study investigated the antimicrobial effects of garlic, potassium lactate and sodium diacetate (PL/SDA) mixture, ?-polylysine, and potassium sorbate (PS) alone or in combinations of them on the growth of foodborne pathogens and production of staphylococcal enterotoxin A (SEA) in ready-to-eat (RTE) pyeonyuk at various temperatures. Lag times (LTs) of Salmonella Typhimurium were longer than those of Staphyloccus aureus at all tested temperatures, regardless of antimicrobial agent. The growth of S. Typhimurium and S. aureus were not observed in pyeonyuk made with 3% PL/SDA mixture or 1.5% ?-polylysine at 10°C. The 0.2% of PS, which is the permitted level for meat products, did not inhibit the growth of S. Typhimurium and S. aureus. Although growth of S. aureus in RTE pyeonyuk with 3% PL/SDA mixture and 1.5% ?-polylysine was observed, SEA was not produced at 17, 24, and 30°C, suggesting the application of PL/SDA mixture or ?-polylysine to reduce the risk related to the consumption of pyeonyuk.