Remote Friction Reduction on Polystyrene Foam Surface by Focused Airborne Ultrasound.

In recent years, various tactile displays having the ability to change their surface friction have been proposed. These displays can express many types of textures and shapes that the materials used for them do not possess. In our study, we found that the ultrasound converged on the surface of polystyrene foam reduces the surface friction. This method has potential applications in disposable and three-dimensional tactile displays. In this study, physical and psychophysical experiments were conducted to verify the effectiveness of the proposed method and to examine the basic conditions under which it is perceived. As a result, we confirmed that the surface friction was reduced on the polystyrene foam, which may be due to the squeeze film effect caused by the external ultrasound excitation of the surface.

Dust Aerosol Detection by the Modified CO2 Slicing Method.

Dust aerosols, which have diverse and strong influences on the environment, must be monitored. Satellite data are effective for monitoring atmospheric conditions globally. In this work, the modified CO2 slicing method, a cloud detection technique using thermal infrared data from space, was applied to GOSAT data to detect the dust aerosol layer height. The results were compared using lidar measurements. Comparison of horizontal distributions found for northern Africa during summer revealed that both the relative frequencies of the low level aerosol layer from the slicing method and the dust frequencies of CALIPSO are high in northern coastal areas. Comparisons of detected layer top heights using collocated data with CALIPSO and ground-based lidar consistently showed high detection frequencies of the lower level aerosol layer, although the slicing method sometimes produces overestimates. This tendency is significant over land. The main causes of this tendency might be uncertainty of the surface skin temperature and a temperature inversion layer in the atmosphere. The results revealed that obtaining the detailed behavior of dust aerosols using the modified slicing method alone is difficult.

Ground-based measurements of column-averaged carbon dioxide molar mixing ratios in a peatland fire-prone area of Central Kalimantan, Indonesia.

Tropical peatlands in Indonesia have been disturbed over decades and are a source of carbon dioxide (CO2) into the atmosphere by peat respiration and peatland fire. With a portable solar spectrometer, we have performed measurements of column-averaged CO2 dry-air molar mixing ratios, XCO2, in Palangka Raya, Indonesia, and quantify the emission dynamics of the peatland with use of the data for weather, fire hotspot, ground water table, local airport operation visibility and weather radar images. Total emission of CO2 from surface and underground peat fires as well as from peatland ecosystem is evaluated by day-to-day variability of XCO2. We found that the peatland fire and the net ecosystem CO2 exchange contributed with the same order of magnitude to the CO2 emission during the non-El Niño Southern Oscillation year of July 2014-August 2015.