The primary goal of this research was to evaluate the effects of light on soymilk, including the oil component. Soybean oil with added chlorophyll a (0, 1, and 2μg/ml), a photosensitizer, was exposed to light (no light [control], broad-spectrum light) and narrow-band wavelengths (430nm, 450nm, and 660nm] for 4h. Chlorophyll completely degraded under broad-spectrum light and 430nm treatments; 64% degradation occurred at 660nm. Oil with chlorophyll addition resulted in significantly higher peroxide values and malondialdehyde concentrations with light exposure to broad spectrum and 430nm wavelengths. Light at 430 and 660 nm degraded chlorophyll and increased risk of oxidation in soybean oil. Soymilk contains low concentrations of chlorophyll, the photosensitizer riboflavin, as well as highly susceptible oxidizable substrates from the soy oil. Soymilk (1% fat from soybean oil) was packaged under a positive flow hood into 5 high density polyethylene (HDPE) packages and stored for 36 days at 4°C under fluorescent lighting (1122 lux ± 439 lux). Control packaging had no light protective additive (LPA; positive (foil-wrapped) and negative control) and the experimental packaging treatments had three levels of LPA (low, medium, high). Chemical and sensory analyses to measure oxidation changes were completed on the product at days, 1, 4, 8, 15, 22, 29, and 36. HDPE packages with high LPA protected the sensory quality of the product as well as the positive control (foil-wrapped) packages for a minimum of 15 days. High-LPA HDPE protected soymilk for 29 days from degradation of riboflavin and limited development of aldehyde end-products associated with photooxidation. Soymilk was treated with food grade TiO2 at levels of 0, 0.5, and 1.0% by weight. TiO2 significantly whitened the product as demonstrated by L* values. TiO2-treated soymilks resulted in significantly improved hedonic scores for appearance, smell, taste, mouthfeel, and aftertaste compared to control soymilk. However, in a second experiment, overall acceptability of TiO2-treated soymilk, at additions of 0.1%, 0.3%, and 0.5% TiO2, was not higher than control soy milk. / Ph. D.

Electricity is the fastest-growing type of end-use energy consumption in the world, and its generation and usage trends are changing. Hence, the power electronics that control the flow and conversion of electrical energy are an important research area. Advanced power electronics with improved efficiency, power density, reliability, and functionality are critical in data center, transportation, motor drive, renewable energy, and grid applications, among others. Wide-bandgap power semiconductors are enabling power electronics to meet these growing demands, and have thus begun appearing in commercial products, such as traction and solar inverters. Looking ahead, even greater strides can be made in medium-voltage systems due to the development of silicon carbide power devices with voltage ratings exceeding 10 kV. The ability of these devices to switch higher voltages faster and with lower losses than existing semiconductor technologies will drastically reduce the size, weight, and complexity of medium-voltage systems. However, these devices also bring new challenges for designers. This dissertation will present a package for 10 kV silicon carbide power MOSFETs that addresses the enhanced electric fields, greater electromagnetic interference, worsened dynamic imbalance, and higher heat flux issues associated with the packaging of these unique devices. Specifically, due to the low and balanced parasitic inductances, the power module prototype is able to switch at record speeds of tens of nanoseconds with negligible ringing and voltage overshoot. An integrated common-mode current screen contains the current that is generated by these fast voltage transients within the power module, rather than flowing to the system ground. This screen connection simultaneously increases the partial discharge inception voltage by reducing the electric field strength at the triple point of the insulating ceramic substrate. Further, field-grading plates are used in the bus bar to reduce the electric field strength at the module terminations. The heat flux is addressed by employing direct-substrate, jet-impingement cooling. The cooler is integrated into the module housing for increased power density. / Ph. D. / Electricity is the fastest-growing type of end-use energy consumption in the world, and its generation and usage trends are changing. Hence, the power electronics that control the flow and conversion of electrical energy are an important research area. Advanced power electronics with improved efficiency, power density, reliability, and functionality are critical in data center, transportation, motor drive, renewable energy, and grid applications, among others. Wide-bandgap power semiconductors are enabling power electronics to meet these growing demands, and have thus begun appearing in commercial products, such as traction and solar inverters. Looking ahead, even greater strides can be made in medium-voltage systems due to the development of silicon carbide power devices with voltage ratings exceeding 10 kV. The ability of these devices to switch higher voltages faster and with lower losses than existing semiconductor technologies will drastically reduce the size, weight, and complexity of medium-voltage systems. However, these devices also bring new challenges for designers. This dissertation will present a package for 10 kV silicon carbide power MOSFETs that addresses the enhanced electric fields, greater electromagnetic interference, worsened dynamic imbalance, and higher heat flux issues associated with the packaging of these unique devices. Specifically, due to the low and balanced parasitic inductances, the power module prototype is able to switch at record speeds of tens of nanoseconds with negligible ringing and voltage overshoot. An integrated common-mode current screen contains the current that is generated by these fast voltage transients within the power module, rather than flowing to the system ground. This screen connection simultaneously increases the partial discharge inception voltage by reducing the electric field strength at the triple point of the insulating ceramic substrate. Further, field-grading plates are used in the bus bar to reduce the electric field strength at the module terminations. The heat flux is addressed by employing direct-substrate, jet-impingement cooling. The cooler is integrated into the module housing for increased power density.

Pallets are the foundation of unit loads and supply chains. They provide a way to store and transport products in an efficient manner. The load capacity of pallets greatly depends on the type of packages carried by the pallet; however, current pallet design methods do not consider the effect of packages on the load carrying capacity of the pallet. This results in excessive use of materials which reduces the sustainability of unit loads, drives costs up, and creates issues for people in the supply chain. The objective of this study was to investigate the effect of a corrugated box's size and head space on pallet deflection and stress distribution on the top of the pallet as a function of pallet stiffness across multiple pallet support conditions. Data analysis identified that box size had a significant effect on the deflection of the pallet. This effect was only significant for warehouse racking across the width and length support conditions. As much as a 53% reduction in pallet deflection was observed for high stiffness pallets supporting corrugated boxes with 25.4 mm headspace when the size was increased from small to large. Meanwhile, no significant effect of box size was found for other supports. The effect of headspace was significant in some scenarios but inconsistent thus more investigation with a larger sample size is recommended. In addition, redistribution of vertical compression stresses towards the supports was observed as a function of the increasing box size. The increased concentration of compression stresses on top of the supports and the resulting lower pallet deflection could significantly increase the actual load carrying capacity of some pallet designs. / Master of Science / Pallets are the foundation of unit loads and supply chains. They provide a way to store and transport products in an efficient manner. The load capacity of pallets greatly depends on the type of packages carried by the pallet; however, current pallet design methods do not consider the effect of packages on the load carrying capacity of the pallet. This results in excessive use of materials which reduces the sustainability of unit loads, drives costs up, and creates issues for people in the supply chain. The objective of this study was to investigate the effect of a corrugated box’s size and head space on pallet deflection and stress distribution on the top of the pallet as a function of pallet stiffness across multiple pallet support conditions. The data from the study identified that box size does have an effect on the deflection of the pallet but, it was only found to be significant for the warehouse racking supports. The highest reduction in pallet deflection was 53% on the high stiffness pallets carrying corrugated boxes with 25.4 mm of headspace as the boxes increased in size. The other support conditions showed no significant effect of the box size. Headspace showed some significant effect in some conditions but was found inconsistent, therefore an investigation with a larger sample size is recommended. In addition, the redistribution of vertical compression stresses towards the supports was observed as a function of increasing box size. This increase in stress on the supports resulted in lower pallet deflection that could significantly increase the actual load carrying capacity of some pallet designs.

No description available.

Yes / This paper isolates litter as a physical incivility in a film-based experiment, demonstrating the impact of litter on participants' anticipation of a wide range of both physical and social incivilities, and on their perceptions of crime prevalence. Such relationships have not previously been examined, partly because litter has rarely been the focus of earlier studies on incivilities. This paper also tests for possible interaction effects in these relationships involving gender (finding no significant interaction), as well as examining whether there is a difference in the anticipation of incivilities and perceptions of crime prevalence between participants exposed to branded as opposed to unbranded litter (finding no difference between the two groups). Litter is often viewed as a tolerable nuisance and not always treated as a priority. This study suggests prioritising funds towards more targeted interventions to reduce litter might result in some ‘quick wins’ – most notably, reducing perceptions of crime prevalence. / The full text will be available at the end of the publishers embargo: 1st March 2018.

Unter dem Motto „Herausforderung Komplexität” wurden die immer dynamischeren Randbedingungen der Branche und vor allem die technologischen Konsequenzen im Verarbeitungs- und Verpackungsmaschinenbau diskutiert. Schwerpunkte bildeten dabei Innovative Maschinenkonzepte + Bewegungstechnik/Robotik, Biogene Verarbeitungsgüter und kreislauffähigen Packstoffe als Herausforderung, Assistenzsysteme als Brücke zwischen Komplexität und Fachkräftemangel, Resiliente Verarbeitungs- und Verpackungsprozesse und Ressourcenschonende Reinigungsprozesse. Nach Keynote-Beiträgen von Herrn Richard Clemens (VDMA Fachverband Nahrungsmittelmaschinen und Verpackungsmaschinen), Herrn Jürgen Dornheim (Procter & Gamble Service GmbH) und Herrn Dr. Ernst Simon (Flexible Packaging Europe) sowie einer gemeinsamen Podiumsdiskussion starteten die zwei wissenschaftlichen Sessions. Das Anwenderforum im Rahmen der Industrieausstellung wurde von Frau Judith Binzer (VDMA Fachverband Nahrungsmittelmaschinen und Verpackungsmaschinen) moderiert. Hier bestand die Möglichkeit, sich über interessante Umsetzungsbeispiele und Technologieträger aus dem Automatisierungsbereich zu informieren, mit Start-ups ins Gespräch zu kommen und sich nicht zuletzt zum Thema Fachkräftenachwuchs auszutauschen.:A: Bewegungstechnik/Robotik B: Hygienegerechte Produktion in der Lebensmittel- und Pharmaherstellung C: Verarbeitung biogener und faserbasierter Packstoffe D: Resilienz von Verarbeitungs- und Verpackungsprozessen E: Innovative Verpackungs-, Maschinen- und Anlagenkonzepte F: Assistenz- und Schulungssysteme gegen Fachkräftemangel

Three types of dried milk (whole, nonfat, and buttermilk) were packaged in a modified atmosphere with a novel palladium-based oxygen removing catalyst and stored for eight weeks at 50°C. Powders stored in air with no catalyst and powders stored with the catalyst in an atmosphere modified to contain 5.7% hydrogen in nitrogen were evaluated by instrumental, chemical, and sensory methods. Hexanal concentrations were measured weekly using solid phase microextraction (SPME) and gas chromatography (GC) to compare the degrees of oxidation in the powders stored with the catalyst to those stored without it. Color changes were also monitored weekly using Hunter's L-, a-, and b-values. At the end of the eight-week period, a paired comparison sensory test was used to ascertain if the catalyst had an effect on odor. Anisidine values were also measured at this point to determine levels of oxidation in the powders. No significant difference was found in levels of oxidation between samples packaged with and without the catalyst in the modified atmosphere. At the end of eight weeks, the average hexanal concentration in the whole milk powder stored with the oxygen scavenger was 1.19 ± 0.20 ppm, while the average hexanal concentration in the air-packed whole milk powder was 1.06 ± 0.08 ppm. The average hexanal concentrations for the buttermilk stored with the catalyst and without were 0.84 ± 0.18 and 0.79 ± 0.15 ppm, respectively. In the nonfat milk powder, the sample stored with the catalyst had an average hexanal concentration of 0.91 ± 0.14 ppm and the sample stored in air without the catalyst had an average hexanal concentration of 0.83 ±0.20 ppm. Difference testing by volunteer sensory panelists also revealed no significant differences. It was expected that the milk powders stored with the catalyst in the modified atmosphere would have lower levels of oxidation and off-odors at the end of the eight weeks. However, the treatment ultimately resulted in no chemical or sensory differences. Thus, the catalyst proved ineffective in the given conditions. This could be due to a loss of the hydrogen required for the catalyst to function as time progressed or a lack of significant oxidation under the conditions employed. / Master of Science in Life Sciences

Crab meat is important to the economy of coastal Virginia. The objectives of this study were to complete a shelf-life study on two different packaging styles of fresh crab meat and to test the inhibition capabilities of Carnobacterium piscicola against the pathogen, Listeria monocytogenes. In a shelf-life study, a 12 ounce food grade polyethylene traditional snap-lid container of fresh crab meat was compared to an 8 ounce SimpleStep® trays with Cryovac™ film of equally fresh crab meat sealed with 10,000 cc/m2/24hr oxygen transmission rate (OTR) film. Eleven g samples were used for the microbial shelf-life study conducted at 4°C for 12 days. Aerobic plate counts of crab meat indicated microbial growth from the SimpleStep® trays with Cryovac™ film in 10,000 cc/m2/24hr OTR versus the polyethylene snap-lid was not significant (P>0.05). In objective two, 25 g samples of fresh and pasteurized blue crab (Callinectes sapidus) meat were inoculated with 0.1ml of each, C. piscicola and L. monocytogenes. Three different concentrations of the inoculation levels were studied on select days at both 4°C and 10°C. Microbial spoilage was defined as 107 CFU/g. In fresh crab meat, at both 4°C and 10°C, crab meat spoilage occurred at 7 days or less. In the pasteurized crab meat, at 4°C and 10°C, spoilage did not occur prior to 26 days, and studies were terminated at 28 days of storage. The growth of the two organisms in fresh crab meat was found to be significant for the differing concentration levels and sampling days (P<0.05). The growth of the two organisms in pasteurized crab meat was significant for different concentration levels, sampling days and temperature (P<0.05). In both fresh and pasteurized crab meat, regardless of the inoculation ratios, the L. monocytogenes and C.piscicola followed similar growth trends, but L. monocytogenes was higher in the 2:2 CFU/g concentration and lower at the 6:2 CFU/g concentration level. Although C. piscicola did not completely inhibit L. monocytogenes growth at any concentration ratio, some inhibition was observed. / Master of Science

This work details a computer-based modeling tool for predicting temperatures in three-dimensional multilayer microelectronic packages. It is capable of modeling surface connections (e.g., wire bonds and pins), edge connections (e.g., leads), and thermal vias. A three-dimensional control-volume finite difference method is used, permitting transient as well as steady solutions. Numerical behavior is examined with respect to the device geometry and external environment. The features of this tool are demonstrated on a sample multilayer package. The effects of the modeling scheme are discussed. An alternate version of the program removes a layer from the numerical model to simplify the solution of the problem. To compensate for the removal of the layer a contact resistance is added. This replaces the thermal resistance the removed layer provided in the z-direction. The x-y conductivity of the adjacent layers are modified based on the removed layer thickness and conductivity. This measure imitates the spreading resistance or conductance that the removed layer provided. The effect of removing a layer in the model is studied, documenting the relationship between layer thickness and conductivity and the error introduced by removing the layer. A simple relationship is sought which can indicate the instances in which the computer model can be simplified. The results are applicable to any method including finite element and series-analytical methods. / Master of Science

Numerous food-borne outbreaks of Escherichia coli O157:H7 have been linked to leafy greens in recent years. An overwhelming amount of lettuce and spinach on the market is sold in modified atmosphere packaging as ready to eat salad mixes. The objectives of this study were to determine the effects of modified atmosphere, storage temperature, and inoculum size on survival of E. coli O157:H7 on cut and whole leaf lettuce and spinach. E. coli O157:H7 H1730 was inoculated onto cut and whole leaves of leaf lettuce and spinach. Samples were held under normal atmospheric conditions or in a modified atmosphere package at either 4ºC or 10ºC to simulate display and abuse temperatures. Leaves were sampled at Days 0, 1 and every other day until visual spoilage occurred (7 days for lettuce, 9 days for spinach). E. coli O157:H7 was able to survive at 4° and 10°C regardless of atmosphere and inoculum size for 7 days on cut and whole lettuce and 9 days on cut and whole spinach. Overall, numbers of E. coli O157:H7 increased (1 log) throughout the storage period on spinach, and decreased on lettuce (1-1.5 log). Significantly higher (P < 0.05) numbers of E. coli O157:H7 were found on lettuce and spinach stored at 10ºC than when stored at 4ºC. There were no significant differences (P > 0.05) in Numbers of E. coli O157:H7 with respect to atmosphere, leaf type or inoculum size. If contamination of lettuce or spinach with E. coli O157:H7 occurred, the pathogen may survive well under typical packaging and storage conditions. / Master of Science in Life Sciences