Hisashi Horio

Development of Fluidics for Driving and Steering Unit of Orchard Sprinkler Boat: Drag Coefficient of the Boat and Fluidics Thrust?

Abstract Small boat with no screw or rudder has been used for showering the canopies of orchards in Thailand. During the showering operation, the boat moves forward by a reaction force of two flat nozzles used for showering. This study discusses the drag coefficient of the boat and the feasibility of using fluidics as a driving and steering unit of the boat in place of conventional flat nozzles. A one-fifth scale model of the boat and a fluidics were built to determine its drag coefficient, the thrust imparted by the fluidics and boat traveling speed. The drag coefficient of the model was found to be inversely proportional to the Froude number and effective in predicting the traveling speed of a boat.

Fine-crushing of Wood-cellulosic Material Modified for its Hydrolysis for Bioethanol Production

Abstract A prototype of a fine-crusher (grinder) of wood-cellulosic materials has been constructed with flail-knives and a rotary sieve rotating independently of each other. Pieces of bamboo in batches were fed into the fine-crusher, the crushed material was then treated with pressurized hot water (sub-critical water) to modify its structure and then hydrolyzed into glucose. With an increase in the diameter of the pores of the rotary sieve, the specific energy requirement for fine-crushing decreased remarkably from 500 to 250 kJ/kg, while the estimated glucose yield at 200°C decreased negligibly from 38% to 35%. The best rotational speed of the rotor and the diameter of the sieve pores were 1500 rpm and 4 mm, respectively.

Optimizing Energy Requirement for Fine-Crushing Wood-Cellulosic Material and its Glucose Yield for Bioethanol Production

Mechanical fine-crushing (grinding), is prerequisite for hydrolysis i.e. saccharification process for bioethanol production from wood-cellulosic materials. Yet, questions remains whether the finer the ground materials the higher the yield of the hydrolysis, or the energy requirement for the fine-crushing process is justifiable among the whole process of the bioethanol production. In particular, recent innovations on enzymatic hydrolysis and yeast fermentation prefer preprocessing of the feedstock material without acid or alkali treatment, to which mechanical fine-crushing of the material should adopt. A prototype of a fine-crusher of wood-cellulosic materials constructed with flail-knives and a rotary sieve has been evaluated in terms of specific energy requirement for fine-crushing and glucose yield of the crushed material. Dry bamboo in batches were fed into the fine-crusher, and the crushed material was then treated with pressurized hot water to modify its structure, followed by enzymatic hydrolysis into glucose. With an increase in the diameter of the pores of the rotary sieve from 3 to 8 mm, the specific energy decreased remarkably from 130 to 50 kJ/kg, while the estimated enzymatic glucose yield also decreased from 25% to 20%.