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The investment casting process offers great freedom of design with the economic advantage of near net shape production and has been widely used to process TiAl alloys. An investigation was undertaken to develop stable and cheap refractory slurry systems, suitable for use as a face coat in the investment casting of titanium aluminides. A TiO2–Al2O3 (TiAlO) based face coat slurry was investigated and compared with a traditional yttria based face coat slurry. After sintering, the chemical inertness of the manufactured shells in contact with molten TiAl alloys was tested by simulating the casting process using a flash re-melting test, in which sample shells were in contact with titanium aluminides at given temperatures for varying time durations and subsequently re-solidified. Compared with yttria, the TiAlO face coat had relatively lower chemical inertness against molten alloys, forming a thick hardened layer at the metal/shell interface with massive interaction products along grain boundaries. The reaction also changed the wetting behaviour of the TiAl on the TiAlO face coat with the contact angle decreasing as a function of interaction time.

The application of Melt Conditioner (MC) for production of high-quality DC billets and slabs at semisolid state is examined. In this technique, liquid metal is continuously fed into a twin-screw melt conditioning device, where the liquid metal or semisolid slurry is subjected to high shear rate, and then delivered continuously into a DC caster. In this paper, the feasibility of MCDC of a wrought aluminium alloy in the semi solid state has been investigated and the possibility of DC casting by MC technique below the liquidus temperature as a novel idea was explored. This idea may challenge the conventional DC casting which is normally performed above liquidus temperature.

A prototype, mechanically ventilated, livestock transport vehicle (for pigs, sheep or cattle) is described. The design complies with current legislation and meets the ‘higher standard’ ventilation requirement for vehicles which are to be used to transport animals for over 8 h. Extraction fans are located at regions of low external pressure on the moving vehicle to optimize performance in transit and provide a controlled variable throughput of air. The system provides air movement over all the animals and is independent of vehicle movement. The design of this prototype system has enabled detailed measurements of heat and moisture production of the animals. Preliminary assessment of the system has been effected during two commercial journeys moving pigs from farms to an abattoir. The variability in heat loss from the animals ranged between 1·4 and 1·9 W kg-1liveweight but in both cases the split between sensible (45%) and latent (65%) heat loss was comparable. These initial data, when augmented with further studies over a wider range of ambient conditions, can be used as the basis for guidelines for the development of improved forced ventilation systems. Such systems will be an essential component in vehicles which are being designed to improve animal welfare in transit.

Most bell pepper fruits are green at the unripe stages, and they become red as they ripen. However, the fruits of new varieties may be white, yellow, orange, red, purple, brown, or black. Ascorbic acid, provitamin A carotenoids, proximate composition, and 11 mineral elements were evaluated in these unusually colored bell peppers ( Capsicum annuum L. ). Over a 2-year period, peppers were grown at the same location following current recommendations for bell pepper production. The fruits were harvested at the unripe and fully colored stages. For each variety, total ascorbic acid and provitamin A contents were determined on two independent samples by microfluorometry and HPLC, respectively. Minerals and proximate composition were determined by AOAC methods. Ascorbic acid ( P P P P R 2 = 0.96), but fat or moisture was not ( P > 0.05). Ascorbic acid increased as color developed in some cultivars, but remained unchanged or decreased in others. Black, purple, and white peppers contained lower ascorbic acid levels compared to the green, yellow, red, brown, or orange peppers. Provitamin A increased as color developed in most cultivars except for yellow varieties. Brown peppers had the highest provitamin A activity compared to other colored peppers.

One of the major stressors associated with the transport of livestock is the thermal microenvironmentin close proximity to the animals. The main determinants of these conditions arethe heat and moisture generated by the animals which needs to be removed from the vehicle tomaintain acceptable conditions that do not compromise the thermoregulatory capability of theanimals. Modern designs of livestock transport vehicles now incorporate mechanical ventilationto control the on-board thermal micro-environment and it is important that there is sufficient fancapacity to match the heat and moisture generated. There has been a paucity of data on the heatand moisture generated by livestock under transport conditions, where avenues for heatexchange are often compromised because of the constraints imposed by the transport processe.g. stocking density. To address this imbalance, a fully commercial livestock transporter (38tonne) has been equipped with controlled ventilation and the associated instrumentation toenable it to operate as a mobile calorimeter enabling the quantification of the heat and moisturegenerated by animals on routine journeys under TRUE transport conditions. The system canoperate on the moving or stationary vehicle. Data have been collected for slaughter weight pigs(100 kg) which show typical maximal heat outputs of about 200 W per pig with an associatedwater production of 0.0502 g/s per pig. These values are markedly elevated during loadingwhen the pigs are more active and also during periods when the lorry is held stationary such asduring mandatory drivers breaks or while awaiting unloading. Such data can form the scientificbasis for design guidelines for improved ventilation systems for animals during transport.

Ribeye steaks (Longissimus muscle) and ground beef from 15 Angus or Angus × Hereford steers slaughtered at weights of 480–500 kg were evaluated for proximate composition, color, β-carotene content and consumer preference. Three groups of five animals were finished on annual ryegrass pasture (Lolium multiflorum), ryegrass and ‘Coastal’ bermu-dagrass hay (Cynodon hybrid), or a feedlot diet.β-carotene content of ribeye steaks and ground beef was higher (p < 0.05) for the forage finished animals than those finished in the feedlot. There was no difference in scores from consumer panels (n = 80) for steaks from feedlot or pasture finished animals, but scores for ground beef from cattle finished on the feedlot diet were higher than other treatments (p < 0.05).

Al7SiMg alloy vertically cast test bars were produced in dry sand moulds by top filling (TF), turbulent bottom filling (TBF) and turbulence-free bottom filling (TFBF) with filtered metal. The test bars were heat treated prior to tensile testing. Scanning electron microscopy examination of polished sections showed that all the test bars contained tangled networks of oxide films which are seen to constitute cracks within the metal. They are more prevalent in the TF and TBF castings. A large number of anomalous features are observed on all fracture surfaces. These are oxide films produced during filling and entrained in the casting. The best description of the skewed distributions of tensile strengths of each set of castings was obtained with the Weibull distribution. Weibull slopes of 11, 20 and 38 were obtained for the TF, TBF and TFBF castings respectively.

Vitamin C (VC) levels (mg/l00 g FW) were determined in 10 varieties of colored bell pepper grown under different field conditions. VC was determined by the microfluorometric method. `Orobelle' (169 mg), `King Arthur' (143 mg), `Valencia' (141 mg), and `Chocolate Bell' (134 mg) had significantly higher VC levels than `Dove' (109 mg), `Ivory' (106 mg), `Blue Jay' (93 mg), `Canary' (90 mg), and `Black Bird' (65 mg). The largest variability (53 mg) in VC levels were observed for varieties that had the highest VC content. Mean VC levels were 143a, 143a, 141a, 136a, 108ab, 93bc, and 63c for the yellow, red, orange, brown, white, purple, and black colors, respectively. Since the Recommended Daily Allowance (RDA) for VC is 60 mg per day, these results suggested that a 100-g serving of fresh bell pepper or less would supply 100% RDA of VC. Therefore, after selecting a color, growers still have the freedom to grow a variety that performs well in their area to produce peppers of high VC contents.

Field performance, ear characteristics and sensory ratings were determined for `Even Sweeter,' `Fantasia', `Silver Queen', `Silverado', `Snow Belle', `Snow White', `Starshine', and `Treasure' sweet corn varieties. Yield (P = 0.60), ears per hectare (P = 0.77), and ear fill (P = 0.22) were not significantly affected by variety, whereas ear set height (P < 0.01), ear length (P < 0.01) and diameter (P < 0.01), tip cover (P < 0.01), eye appeal (P < 0.01), as well as sensory ratings of appearance (P < 0.01), sweetness (P < 0.01), and flavor (P < 0.01) after cooking were. None of the selected varieties was rated unacceptable. However, because mean separation tests at the 5% and 10% levels did not provide clear groupings and because all attributes have to be considered together in variety evaluation, a global performance index (GPI) was developed by adding the ranks of each variety for each attribute. GPI ranged between 28 for `Treasure' and 59 for `Snow White' on a 10 (best) to 80 (worse) scale. `Treasure', `Silver Queen', and `Even Sweeter' were above average. These varieties may be considered best performers for white sweet corn production in central Alabama.