Here we present a biofuel cell that can turn glucose and starch into electric energy. Compartmentalized with a Nafion® membrane, the cell oxidizes biofuels and reduces O2 in the anolyte and catholyte, respectively. Glucose is oxidized by glucose oxidase (GOx), and the released electrons are transported to the anode by 1,4-benzoquinone (BZQ). Oxygen is reduced by laccase (Lac) that receives electrons from the cathode carried by 2,2'-azino-bis(3- ethylbenothiazoline-6-sulfonate) (ABTS). When starch is fed, amylase is added in the anolyte for saccharification. The cell can generate a power density of ca. 50 μW/cm2 at 25°C rapidly, even with a starch fuel. In this paper, we will detail the factors that affect the cell performances and demonstrate the biofuel cell's niche in electronic devices.
Firmness is an important biomaterial property in assessing the internal quality of agricultural products. This article briefly summarizes recent research results of a new frequency-based firmness index for solid fruits and vegetables of ellipsoidal shape. This new firmness index is in fact a generalization of the conventional ones targeted for spherical fruits and vegetables. Meanwhile, it can also serve as a dynamic Modulus of Elasticity (MOE) estimator. The development of this new firmness index extends the potential applications of non-destructive firmness estimation to non-spherical fruits and vegetables. The theory of formulation is first introduced, followed by a discussion on two experimental case studies, “tri-star” pear and Chinese radish. The results show that the new firmness index is indeed more robust and accurate, especially for ellipsoids with long principal axes ratios.
In order to clarify the soil deformation at the ground contact surface, traveling tests using a rubber-coated rigid wheel were carried out with −5%, 5%, 10%, 20% and 40% slip using a sophisticated soil bin test apparatus. The displacement of soil particles at the ground contact surface was observed through the movement of acrylic wires (1 mm in diameter) laid down on the soil surface. PTV (Particle Tracking Velocimetry), an effective image processing technique, was employed to detect the movement of the acrylic wires using image processing of a series of pictures. The detected movement is assumed to coincide with that of soil particles at the same position. Accordingly, the movement of soil particles could be successfully measured and analyzed. In addition, the soil deformation under the wheel was also measured using PIV (Particle Image Velocimetry). Both measures were then analyzed and the characteristics of soil deformation clarified. The mathematical model for the soil displacement at the ground contact surface showed good agreement with the measured values, except for at high slip.
A strawberry harvesting robot consisting of a four DOF manipulator, an end-effector with suction pad, a three camera vision system and a rail type traveling device was developed as a trial to conduct experiments in a tabletop culture greenhouse. In order to harvest the strawberries with curved or inclined peduncles, a wrist joint which can rotate 15 degrees to the left or right from its base position was added. On the algorithm side, peduncle inclination angle was measured by the center camera. Harvesting experiments show that it was possible to precisely harvest more than 75% of fruits which were not occluded by other fruits with the developed robot. Experimental data also show that peduncle length, color and inclination pattern change with the seasons. Complex situations often exist in the real field conditions such as limited visibility of back end strawberries, occluded fruits, obstructions and complex peduncle patterns. Further studies are desirable to automate the harvesting task using a robot.
Harvested rice (cv. Koshihikari) was microwave-radiated up to 60, 70 and 80°C and kept heat-treated for 0, 1 and 3 min, dried and then stored at 40°C for 6 months. A pronounced change in chemical properties of control rice during storage was observed such as increase in fat acidity, soluble sugars, total amylose and insoluble amylose content, while a decrease was founded in total starch content, and soluble amylose content. The above changes also occurred in heat shock treated rice, but with certain extent of delay. The heat shock treatment (HST) delayed the increasing rate of fat acidity. The HSTs at 60 and 70°C were effective in keeping the values of total amylose and insoluble amylose content low. The results showed that HST would benefit rice quality maintenance during storage.
To develop a practical and fast analysis tool for interaction studies of soil-wheel system, the algorithm of our two-dimensional discrete element method (DEM) program was modified, and a simple parallelization method, either cyclic division or block-cyclic division, was introduced at the elemental loop. The developed parallel DEM program was found to be sufficiently accurate. The application of the cyclic division method was not effective when executed on a clustered 4-CPU system with the current number of DEs. Both divisions were found to be effective when executed on a PC with multi-core CPUs with shared L2 cache memory, and the possible range of block width in the block-cyclic division method was from 1 to 8.