The principles of Design for Manufacturing and Assembly (DFMA) were applied to the redesign of a manual shredding machine used to harvest breadfruit in the Republic of Haiti. The DFMA methodology examined each function of the shredder assembly to determine if a part could be eliminated or combined with another part and if there were simpler ways to meet the performance criteria without sacrificing quality. A breadfruit shredder designed by a previous senior design group that met the customer and engineering specifications was subjected to the DFMA process resulting in a machine that was easier to build in a developing country, used materials that were more commonly available, had a reduced number of parts, was more robust, was easier to clean and keep sanitary, and cost less to make.

In an effort to establish the optimum conditions for depositing high-quality diamond films at high deposition rates using a plasma torch, modelling work has been focused on developing a realistic model for determining temperature, velocity and particle density distributions in the plasma jet. To enhance molecular decomposition, which favourably improves diamond synthesis, high-speed gas is passed through a supersonic anode nozzle. In the subsequent low-pressure chamber, the chemical reactions cannot follow the fast macroscopic translation, resulting in distributions of dissociated precursors that are far from chemical equilibrium. To simulate the finite rate chemistry, a generalized implicit multi-component algorithm is introduced and examined in the context of a two-dimensional computational model of a chemically reacting Ar- supersonic plasma jet. The scheme can be adapted to other plasma flows in which chemical non-equilibrium is encountered.

A chart relating temperature and velocity to the drying time of single layered shredded breadfruit, Artocarpus altilis, is presented. Breadfruit, which can be dried and ground into gluten-free flour, was placed on screens in a controlled drying chamber. A design of experiment based on the independent variables of temperature (21, 40, 558C), absolute humidity (0.01, 0.01125, 0.0125 kg/kg dry air), and air velocity (2.5, 4, 6 m/s) was executed. The data suggested that the moisture ratio is exponentially related to the time spent drying, thus the Page model was used to analyze a response surface that identified the key factors that influence drying. An analysis of the response surface indicated that temperature, velocity, and initial moisture content are the critical drying factors. To enable drying predictions, two variable quadratic equations and a chart relating drying time to temperature and velocity, based on 10% moisture content as dry, are given. Practical applicationsBreadfruit, Artocarpus altilis, is a fruit that grows in the tropical regions of the world. Drying breadfruit is a cost effective means of preserving this resource which can be ground into a gluten-free flour. Processing breadfruit flour into nutritious products is an opportunity to overcome hunger, increase food security, and contribute to sustainable development on many island nations. Equations based on temperature and velocity and a chart relating these factors to an adequate drying time are presented. This original work provides new understandings of these variables and the chart relating drying time to air temperatures and velocities would be useful in post-harvest economic trade-off charts and system scaling. K E Y W O R D Sbreadfruit flour, fruits and vegetable drying, thin-layer drying

Experiments to determine the optimal size shred of breadfruit for sun drying in the Caribbean were conducted and verified. To determine optimal shred size, ease of shredding and handling as well as the drying characteristics were considered. Additional experiments compared the drying characteristics of breadfruit to several types of produce more readily available for use in the laboratory and examined the effect of alternative bases or backgrounds for sun drying. An optimal surface area to volume ratio is recommended and found to dry breadfruit under average Caribbean conditions (27-30 ˚C, 60-65% RH, ~800 W/m2 solar radiation and 1.5-2.0 m/s prevailing winds) in about three hours.

No abstract