This study was conducted to determine the effects of compression on pressure drops in non-metallic flexible duct. Duct sizes of 12”, 14” and 16” diameters were tested at a five different compression ratios (maximum stretch, 4%, 15%, 30% and 45%) following the draw through methodology in ASHRAE Standard 120 -1999 – Methods of Testing to Determine Flow Resistance of Air Ducts and Fittings. With the pressure drop data gathered, equations were developed to approximate the pressure loss at a given air flow rate for a given duct size. The data gathered showed general agreement with previous studies showing an increase in compression ratio leads to an increase in static pressure loss through the duct. It was determined that pressure losses for compression ratios greater than 4% were over four times greater than maximum stretched flexible duct of corresponding duct size. The increased static pressure losses can lead to decreased performance in HVAC systems. The findings of this study add to the existing ASHRAE and industry data for flexible duct with varying compression ratios.

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The traditional way of processing milk is the application of heat to destroy undesirable microorganisms. Though heat is an effective means of doing the job, it is associated with several limitations. High pressure (HP) processing has the potential for eliminating microorganisms without affecting the natural quality of the raw material. As a result, it has become a promising technique in recent years. Many factors are reported to influence HP destruction of microorganisms, the most important ones include food composition (i.e., lipid, carbohydrate and protein contents), water activity, process temperature, and mode of pressure treatment. Therefore, the objectives of this research were to: (a) evaluate the effect of milk composition on destruction of E. coli by HP, (b) evaluate kinetic models for spoilage and pathogenic microorganism in milk and the effect of different pressure mode (pulse and static) on the destruction rates; and (c) to evaluate the effect of milk type (UHT and raw milk) and temperate on destruction of microorganism.

Human newborns' response to decreased sound pressure level (SPL) was investigated with a localized headturning habituation procedure. Following criterion orientation (three headturns toward the sound out of four consecutive trials) and habituation (three consecutive trials with no headturns or headturns away from the sound), study 1 and 2 assessed newborn female infants' (M age = 41 hrs.) responses to lower-volume sounds immediately following habituation and following a 55-sec delay, respectively. Generalization of habituation to decreased volume following delay with recovery immediately following habituation was observed. Immediate recovery to decreased SPL contradicts a selective receptor adaptation view because a lower-intensity stimulus does not engage a separate set of receptor cells. It is proposed that generalization of habituation following delay involves recognition of the sound as familiar despite variations in volume.

Two classes of parameters are important in product quality control and process design: thermo-physical and rheological properties. Reliable estimates of thermal properties (thermal conductivity, diffusivity, density, specific heat, and glass transition temperature) are needed to model the rate of heat transfer during food processing. Measurements of rheological parameters like viscosity and elasticity have been recognized as important tools to provide fundamental insights on structural organization of the food. Small amplitude oscillatory testing is useful in evaluation of gel characteristics and texture development in different food products. Proper design of industrial plants, modeling and automation in food process industry require data on these properties for better quality control and improve the shelf life. Thermal processing has been a traditionally accepted method for developing safe and shelf-stable products. However, a disadvantage of thermal treatment is the reduced sensory and nutritional qualities. High pressure (HP) treatment, a novel non-thermal preservation technique, is used for producing high quality products. HP processing can also be used to achieve products with better textural properties and improved nutrition when supplemented with proteins. / This research was carried out in two parts. In first part, experiments with mango pulp were carried out at four temperatures (20, 40, 60 and 80°C) and total soluble solids concentrations (15, 20, 30 and 40°Brix) and their rheological and thermo-physical properties were evaluated and modeled. Thermal properties of mango puree were primarily dependent on the moisture content of the sample, and increased with temperature and decreased with concentration. Density showed a reverse trend. Glass transition temperatures increased with an increase in concentration indicating better stability. Separate models were developed for each thermal property as a function of temperature and concentration (R2 >0.90). Mango puree exhibited pseudoplaticity during steady shear measurements, and the power law model well described their flow behavior. Consistency coefficient increased with concentration and decreased with temperature. The flow behavior index decreased with concentration and generally increased with temperature beyond 40°C. Dynamic oscillation shear measurements revealed that mango puree behaved like a weak gel and demonstrated visco-elastic properties. / In the second part, experiments were divided in to two parts. In first part, the original soluble solids in mango puree (28°Brix) was lowered to 20, 23 and 26°Brix and each was supplemented with 2, 5 and 8% of whey protein. Effect of HP treatment at 425, 500, and 575 MPa with 0, 3 and 6 min holding times on rheological properties were evaluated. Pressure treatment resulted in a positive effect on elastic (G') and viscous modulii (G") as well as complex viscosity (eta*). Values of G' were higher than G" demonstrating the product to behave more and more like a gel. The changes in rheological parameters at 500 MPa were modeled based on soluble solids and protein content. In the second part of the experiments, the protein (P) and soluble solids concentrations (S) were simultaneously varied maintaining a total solids content at 28% (same as in the original mango puree) and their combined influence (P/S: 2/26, 3/25, 5/23, 7/21 and 8/20) on the rheology of the product after selected HP treatments (425-575 MPa, 0-6 min) were evaluated. The effects of holding time and pressure level were similar to those observed previously in first part of this study. However, the positive effect of added protein was over dominated by negative effect of the simultaneous decrease in the soluble solids concentration, resulting in an overall decreasing effect as protein content increased (with a same magnitude decrease in soluble solids content). Developed models well predicted the combined influence of protein and soluble solids concentration on rheological parameters (R2>0.85). / Sensory evaluation of mango puree supplemented with protein (2, 5 and 8%) was performed before and after high pressure treatment (500MPa/3min) using a nine point hedonic scale. The quality parameters chosen were color, sweetness, mouthfeel, flavor and acceptability. Sensory evaluation results indicated that protein enrichment up to 5% level did not adversely affect the sensory qualities.

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