Silicon ingot casting: Heat Exchange Method (HEM). Multi-wire slicing: Fixed Abrasive Slicing Technique (FAST). Phase 3 and phase 4: Silicon sheet growth development for the large area sheet task of the low-cost solar array project

Several areas of silicon sheet growth development are addressed including: silicon ingot casting, heat exchanger method, multiwire slicing, and fixed abrasive slicing technique

Silicon ingot casting: Heat exchanger method. Multi-wire slicing: Fixed abrasive slicing technique, phase 3

In the area of ingot casting the proof of concept of heat exchanger method (HEM) was established. It was also established that HEM cast silicon yielded solar cell performance comparable to Czochralski grown material. Solar cells with conversion efficiencies of up to 15% were fabricated. It was shown that square cross-section ingots can be cast. In the area of crystal slicing, it was established that silicon can be sliced efficiently with the fixed abrasive slicing technique approach. This concept was carried forward to 10 cm diameter workpiece

Wire blade development for Fixed Abrasive Slicing Technique (FAST) slicing

A low cost, effective slicing method is essential to make ingot technology viable for photovoltaics in terrestrial applications. The fixed abrasive slicing technique (FAST) combines the advantages of the three commercially developed techniques. In its development stage FAST demonstrated cutting effectiveness of 10 cm and 15 cm diameter workpieces. Wire blade development is still the critical element for commercialization of FAST technology. Both impregnated and electroplated wire blades have been developed; techniques have been developed to fix diamonds only in the cutting edge of the wire. Electroplated wires show the most near term promise and this approach is emphasized. With plated wires it has been possible to control the size and shape of the electroplating, it is expected that this feature reduces kerf and prolongs the life of the wirepack

Overview of a new slicing method: Fixed Abrasive Slicing Technique (FAST)

The fixed abrasive slicing technique (FAST) was developed to slice silicon ingots more effectively. It was demonstrated that 25 wafers/cm can be sliced from 10 cm diameter and 19 wafers/cm from 15 cm diameter ingots. This was achieved with a combination of machine development and wire-blade development programs. Correlation was established between cutting effectiveness and high surface speeds. A high speed slicer was designed and fabricated for FAST slicing. Wirepack life of slicing three 10 cm diameter ingots was established. Electroforming techniques were developed to control widths and prolong life of wire-blades. Economic analysis indicates that the projected add-on price of FAST slicing is compatible with the DOE price allocation to meet the 1986 cost goals

Effect of alternative protein sources on growth performance, plasma mineral concentration, bone mineralisation and mineral digestibility in broiler chickens

An experiment was conducted to investigate the effect of rapeseed meal (RSM), sunflower meal (SFM), canola meal (CM) and guar meal (GM) respectively at 50, 60, 100 and 50g/kg in a maize soyabean based diet on growth performance, plasma mineral concentration, bone mineralisation and mineral digestibility in broiler chickens. The control diet had soya bean meal (SBM; 320g/kg). Day old Hubbard broilers were allocated to five treatments each with 4 replicates and 10 birds. Partial replacement of SBM with other protein sources resulted in heavier (P<0.05) birds compared to control. Bone mineralisation was not affected (P>0.05) by diets. Plasma Ca concentration was higher (P<0.05) in birds fed GM compared to all other treatments. Retention of P, Mg, Na, Cu was increased and Ca retention was decreased in birds fed control diet whereas, no differences (P>0.05) were observed between treatments in K, Fe and Mn retention values. In conclusion, alternative protein sources improved growth but had variable effects on mineral utilisation

Effect of alternative protein sources on growth performance, plasma mineral concentration, bone mineralisation and mineral digestibility in broiler chickens

An experiment was conducted to investigate the effect of rapeseed meal (RSM), sunflower meal (SFM), canola meal (CM) and guar meal (GM) respectively at 50, 60, 100 and 50g/kg in a maize soyabean based diet on growth performance, plasma mineral concentration, bone mineralisation and mineral digestibility in broiler chickens. The control diet had soya bean meal (SBM; 320g/kg). Day old Hubbard broilers were allocated to five treatments each with 4 replicates and 10 birds. Partial replacement of SBM with other protein sources resulted in heavier (P<0.05) birds compared to control. Bone mineralisation was not affected (P>0.05) by diets. Plasma Ca concentration was higher (P<0.05) in birds fed GM compared to all other treatments. Retention of P, Mg, Na, Cu was increased and Ca retention was decreased in birds fed control diet whereas, no differences (P>0.05) were observed between treatments in K, Fe and Mn retention values. In conclusion, alternative protein sources improved growth but had variable effects on mineral utilisation