On the onset of fracture as a silicon-based polymer converts into the ceramic phase

Silicon-based polymers evolve into refractory ceramics when heated gradually up to ~1000°C. The conversion is accompanied by the loss of gaseous species, and by a two-fold increase in density. The shrinkage can produce microcracks if the heating rate is too high, or if the specimen is too thick. This communication builds on earlier work whereby the measurement of gas evolution, and its relationship with viscous flow, are related to the onset of fracture in disk-shaped green (polymer) samples. The onset is determined as a function of the thickness of the disks, and of the heating rate. The results are presented in the form of a processing map. The overlay with gas evolution, and strain-rate measurements, suggest that fracture initiates with the release of hydrogen and methane, starting at temperatures near 750°C.     

Motion control of underactuated linkage robot based on gymnastic skill

In this paper, a reproduction of a swing‐up and a giant swing motion of underactuated robots based on technique of the horizontal bar gymnast is discussed with focusing on an equivalent center of mass (ECM) of underactuated robots and the gymnast. At first, the behaviors of the ECM of the gymnast (ECMG) are analyzed by using a motion capturing technique and an efficient motion of the ECMG for the swing‐up and for the giant swing motion are identified from analysis results, respectively. Next, a partial linearization method, which can realize that the ECM of the Acrobot (ECMA) replicates this efficient motion, is designed and reproduces the underactuated robots the swing‐up and giant swing motion like the gymnast. Finally, an effectiveness of the proposed controller is shown by numerical simulations.     

Compositional Dependence of Normal Spectral Emissivity of Molten Cu-Fe Alloy

Metallurgical and Materials Transactions B - Normal spectral emissivity of molten Cu-Fe alloy with different compositions was measured at the wavelength of 807 nm using an electromagnetic...     

Multimodal sensing and active continuous closed‐loop feedback for achieving reliable manipulation in the outdoor physical world

The use of field robots can greatly decrease the amount of time, effort, and associated risk compared to if human workers were to carryout certain tasks such as disaster response. However, transportability and reliability remain two main issues for most current robot systems. To address the issue of transportability, we have developed a lightweight modularizable platform named AeroArm. To address the issue of reliability, we utilize a multimodal sensing approach, combining the use of multiple sensors and sensor types, and the use of different detection algorithms, as well as active continuous closed‐loop feedback to accurately estimate the state of the robot with respect to the environment. We used Challenge 2 of the 2017 Mohammed Bin Zayed International Robotics Competition as an example outdoor manipulation task, demonstrating the capabilities of our robot system and approach in achieving reliable performance in the fields, and ranked fifth place internationally in the competition.     

Chemical‐Free Approach for Z‐Isomerization of Lycopene in Tomato Powder: Hot Air and Superheated Steam Heating above the Melting Point of Lycopene

Z‐isomers of lycopene exhibit higher bioavailability and antioxidant capacity than those of the all‐E‐isomer. Therefore, it is important to develop an efficient and environmentally friendly procedure for Z‐isomerization. The current methods for Z‐isomerization of (all‐E)‐lycopene use toxic chemicals such as organic solvents and catalysts. This study is aimed to develop a chemical‐free method for Z‐isomerization of (all‐E)‐lycopene in tomato powder by hot air and superheated steam heating. The Z‐isomerization reaction is promoted by heating above the melting point of lycopene. When heated with superheated steam, the thermal decomposition of lycopene is suppressed compared to that when heated with hot air. When tomato powder is heated at 240 °C for 5 min by superheated steam, the total Z‐isomer content and remaining lycopene are 69.0% and 90.7%, respectively, while with hot air heating, the total Z‐isomer content and remaining lycopene are 69.9% and 68.0%, respectively. These results indicate that the thermal Z‐isomerization of lycopene occurs in the molten state and heating in a low oxygen atmosphere suppresses the thermal decomposition of lycopene. Practical Applications: Tomato powder rich in lycopene Z‐isomers is an important ingredient for the food and animal feed industries. Since Z‐isomers of lycopene are more soluble in solvents including ethanol which is a low‐toxicity and environmentally friendly solvent, the efficiency of lycopene extraction with ethanol can be improved by using the Z‐isomer‐rich tomato powder as a raw material. The obtained Z‐isomer‐rich extract has a high added value because the Z‐isomers have higher bioavailability and antioxidant capacity than those of the all‐E‐isomer. In addition, since lycopene Z‐isomers exhibit higher accumulation efficiency and better color improvement in hen egg yolks than those of the all‐E‐isomer, Z‐isomer‐rich tomato powder is an effective animal feed.     

Pleiotropic Effects of Sodium-Glucose Cotransporter-2 Inhibitors: Renoprotective Mechanisms beyond Glycemic Control

Diabetes mellitus is a major cause of chronic kidney disease and end-stage renal disease. However, the management of chronic kidney disease, particularly diabetes, requires vast improvements. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally developed for the treatment of diabetes, have been shown to protect against kidney injury via glycemic control, as well as various other mechanisms, including blood pressure and hemodynamic regulation, protection from lipotoxicity, and uric acid control. As such, regulation of these mechanisms is recommended as an effective multidisciplinary approach for the treatment of diabetic patients with kidney disease. Thus, SGLT2 inhibitors are expected to become key drugs for treating diabetic kidney disease. This review summarizes the recent clinical evidence pertaining to SGLT2 inhibitors as well as the mechanisms underlying their renoprotective effects. Hence, the information contained herein will advance the current understanding regarding the pleiotropic effects of SGLT2 inhibitors, while promoting future research in the field.     

Mass transfer in polycrystalline ytterbium monosilicate under oxygen potential gradients at high temperatures

Mass transfer in polycrystalline Yb₂SiO₅ wafers with precise composition control was evaluated and analyzed by oxygen permeation experiments at high temperatures using an oxygen tracer. Oxygen permeation proceeded due to mutual grain boundary diffusion of oxide ions and Yb ions without synergistic effects such as acceleration or suppression. The oxygen shielding properties of Yb₂SiO₅ were compared with those of the other line compounds such as Yb₂Si₂O₇ and Al₂O₃ based on the determined mass transfer parameters. It was found that the more preferentially an oxide ion diffuses in the grain boundary compared to the interior of the grain, the greater the effect of suppressing the movement of the oxide ion by applying an oxygen potential gradient becomes.     

Predicting nitrogen leaching with the modified LEACHM model: validation in soils receiving long-term application of animal manure composts

A variety of process-based models have been developed for predicting nitrogen (N) dynamics in agro-ecosystem; however, no reliable models have been validated for N leaching from soils receiving a long-term application of different types of animal manure composts. The Leaching Estimation and Chemistry Model (LEACHM) was recently modified by incorporating the basic structure of Rothamsted Carbon Model for extending its ability to describe soil organic matter decomposition and subsequent N leaching in soils rich in organic matter. We evaluate the applicability of the modified LEACHM in cropped Yellow soils receiving 10-year application of cattle or swine manure compost in addition to chemical fertilizers, where high-frequency field monitoring data of soil water contents, soil N contents and leachate N concentrations were available for the last 3 years. Particular attention was paid to determine all input parameters from independent measurements, parameterization from known soil properties or databases without optimisation to fit the measured field data. The model reasonably predicted temporal changes in the soil NH₄-N and NO₃-N contents, and inorganic N concentrations in the leachate as well as their differences due to different manure compost/chemical fertilizer applications. The simulations of leached N concentration yielded a Willmott index of agreement (IA) of 0.62–0.68, with those for soil moisture, soil nitrate content and crop N uptake all within an acceptable IA range. In view of the good performance without site-specific calibrations, the modified LEACHM appears to be a valuable tool for predicting N leaching from cropped soils receiving long-term manure compost applications.