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This thesis deals with the global aspects of plasmaconvection in the magnetosphere as measured by the low-altitudepolar orbiting Astrid-2 and FAST satellites. The major focus ison the electric field measurements, but they are alsocomplemented by magnetic field, ion and electron particle data,which is fundamental for the understanding of theelectrodynamics of the high-latitude auroral ovals and polarcap, which are the regions analysed here. The essential subjectof this thesis is the so-called magnetic reconnection processthat drives plasma convection in the Earth's magnetosphere. Itis shown that the ionospheric convection, being intimatelycoupled to the magnetospheric convection, responds in about15-25 min depending on geomagnetic activity after the arrivalof the solar wind at the magnetopause. It also responds on alonger time scale, around 55-75 min, which is interpreted asthe unloading of solar wind energy previously stored in thelarge-scale current system of the magnetotail. These resultshave been found previously using ionospheric parameters such asthe auroral electrojet AL index. What is new is that these sameresults are reproduced by using a discrete set of cross-polarpotential measurements. Using an extensive set of electric andmagnetic field data combined with particle precipitation datafrom the FAST satellite, it is shown that the reconnectionprocess can also be applied to explain features of sunwardplasma convection in the polar cap with a likely antiparallelmerging site in the lobe magnetopause region. The lobereconnection is found to depend strongly on IMF Byand to coexist with dayside subsolar merging.Finally, a comparison is performed between the Weimer electricfield model and Astrid-2 electric field data. Empiricalelectric field models are important in understanding thecomplete convection pattern at any one time, something, whichcannot be provided by measurements from single satellites. <b>Keywords:</b>Satellite measurements, electric fields,magnetosphere, magneticreconnection, plasma convection, lobecell convection, empirical electric field models.

Poultry slaughtering encompasses a series of processing steps with the objective of harvesting the consumable meat. The scalding process consists of the submersion of carcasses in hot water tanks to facilitate the removal of feathers during slaughter. However, the use of a common scalding tank increases the likelihood of carcass cross contamination considering that dirt, fecal material and even digestive and intestinal contents carrying pathogens and other bacteria are widely spread during this operation. Similar cross contamination occurs in the process of chilling carcasses, which also requires submersion of broilers in communal tanks filled with ice and cold water. A plausible approach to reduce contamination in scalders or chillers is the use of Pulsed Electric Fields (PEF) to decontaminate scalder/ chiller water. PEF uses electricity to kill bacteria suspended in liquid media and could be utilized in poultry scalders and chillers to reduce bacterial contamination on carcasses and reduce the potential risk of pathogens reaching the final consumer. A pilot scale system was assembled by the use of a pulse electric field generator (Model SF-700, Simmons. Eng. Co., Dallas, GA) coupled with a commercial scalding tank (Dunkmaster®, Knase Company Inc, MI). C. coli and C. jejuni along with marker strains of Novobiocin and Nalidixic acid resistant S. typhimurium and S. enteritidis strains were used in challenge studies evaluating the effects of the PEF on carcasses, scalder and chiller water contamination. The system was evaluated with 0, 0.5, and 1% sodium chloride in the water with 40 volts of electric current and 0.54 of amperage. Samples were collected at 0, 40, 80, 160, 200 s of treatment with a 10 s on, 5 s off cyclical pulses. The use of PEF in regular scalder/chiller water showed little effect on Salmonella and Campylobacter reductions. However, with the addition of 0.5% NaCl caused a significant (P<0.5) log CFU/ml reduction of Salmonella and Campylobacter within the scalder/chiller water at 40, 80, and 160 seconds respectively.

<p>This thesis deals with the global aspects of plasmaconvection in the magnetosphere as measured by the low-altitudepolar orbiting Astrid-2 and FAST satellites. The major focus ison the electric field measurements, but they are alsocomplemented by magnetic field, ion and electron particle data,which is fundamental for the understanding of theelectrodynamics of the high-latitude auroral ovals and polarcap, which are the regions analysed here. The essential subjectof this thesis is the so-called magnetic reconnection processthat drives plasma convection in the Earth's magnetosphere. Itis shown that the ionospheric convection, being intimatelycoupled to the magnetospheric convection, responds in about15-25 min depending on geomagnetic activity after the arrivalof the solar wind at the magnetopause. It also responds on alonger time scale, around 55-75 min, which is interpreted asthe unloading of solar wind energy previously stored in thelarge-scale current system of the magnetotail. These resultshave been found previously using ionospheric parameters such asthe auroral electrojet AL index. What is new is that these sameresults are reproduced by using a discrete set of cross-polarpotential measurements. Using an extensive set of electric andmagnetic field data combined with particle precipitation datafrom the FAST satellite, it is shown that the reconnectionprocess can also be applied to explain features of sunwardplasma convection in the polar cap with a likely antiparallelmerging site in the lobe magnetopause region. The lobereconnection is found to depend strongly on IMF B_yand to coexist with dayside subsolar merging.Finally, a comparison is performed between the Weimer electricfield model and Astrid-2 electric field data. Empiricalelectric field models are important in understanding thecomplete convection pattern at any one time, something, whichcannot be provided by measurements from single satellites.</p><p><b>Keywords:</b>Satellite measurements, electric fields,magnetosphere, magneticreconnection, plasma convection, lobecell convection, empirical electric field models.</p>

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 105-112).

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Committee Chair: A. Rahman Zaghloul ; Committee Members: W. Russell Callen and Doug Yoder. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 154-161).

Cheese ripening is a costly and lengthy process. Increasing the enzyme pool in the cheese curd has been shown to accelerate the cheese ageing process, enhance flavour and texture. The characteristics of two lactic acid bacteria attenuated by pulsed electric fields were studied in a milk system and in cheese slurry. The potential of accelerating cheese ripening via the addition of starter cultures attenuated by pulsed electric fields (PEF) was studied. / Pulsed electric field treatment was performed in a static treatment chamber using bi-polar waveform with a field intensity of 20 kV and 2 mus pulse width. The number of pulses ranged from 10 to 500. Evaluation of the starter cultures was assessed through the analysis of acidifying abilities, survival fractions, enzymatic activities and proteolysis (RP-HPLC and Cd-ninhydrin) in water soluble nitrogen extracts following the different attenuation treatments. / Pulsed electric fields significantly affected the general viability of the cells through a delayed acidification and an inhibition of enzymatic activity. A study in cheese slurry systems showed that the cultures under investigation were not able to provide an increased proteolysis levels following PEF treatment. The results of this study also suggest that optimal PEF treatment varies for each LAB strain and that the Lactococcus strains do not possess high enough proteinase and peptidase activities to be beneficial for the acceleration of cheese ripening.

Birds nest under electric and magnetic fields (EMFs) generated by transmission liners which may affect their reproductive success and/or melatonin governing their circadian and circannual cycles. Over two years, captive kestrels were used to determine whether EMFs affect their plasma melatonin concentrations and their reproductive success. EMFs were equivalent to that which wild kestrels are exposed to while nesting under 735 kV transmission fines, and daily exposure used in the captive study (88--98% time budget) was potentially equivalent to that of wild kestrels (90% X, 80% X). Captive kestrels were housed in control or EMF conditions to determine short-term (one season; S-EMF) and longer-term EMF (two seasons; L-EMF) effects. / Plasma melatonin in adult EMF males was suppressed at 42 d and elevated at 70 d of EMF exposure compared to controls. Melatonin levels in EMF males at mid-season were similar to controls at season's end, suggesting a seasonal phase-shift. Melatonin was suppressed in L-EMF fledgling birds but not in adult females or nudes (1995) at 70 d. Plasm melatonin, higher in adult males than females at 70 d post-pairing, was not directly associated with body mass changes in kestrels. / Captive EMF birds were more active and alert but groomed less often than controls. EMF exposure affected reproductive success of kestrels. Fertility and fledging success were higher, and hatching success lower in S-EMF clutches. Hatching success was higher, but fledging success lower in L-EMF clutches. In S-EMF clutches, mean egg volume and mass were greater, eggs had slightly more albumen but thinner eggshells, and embryos were larger than controls. L-EMF hatchlings were heavier than controls. / The melatonin results for male kestrels indicate that kestrels perceive EMFs as light, thus altering their photoperiod. Photoperiodic manipulations advance molt onset, which is associated with increased body mass in male kestrels. S-EMF males were heavier at 56 d of exposure when molt began, but this was unlikely related to feed intake winch was unchanged. EMF exposure had no effect on body mass and pectoral muscle scores of reproducing females. The sexually-dimorphic response in body mass and melatonin concentrations suggests that male kestrels may be more sensitive to EMF exposure than females.

The application of pulsed electric fields (PEF) in food processing is a novel technique that requires careful study. In addition, improved understanding of the effect of PEF parameters on both physical and qualitative attributes of agrifood products is a requirement for the application and control of this emerging technology. PEF parameters investigated were pulse widths of 100, 200, and 300 mus, with electric field strengths of 0.75 and 1.5 kV/cm. The amount of pulses used for apples was up to 60, whereas up to 120 pulses were used for potatoes. Initially, apple and potato slices were exposed to various combinations of PEF parameters in order to evaluate the change in their electrical conductivities as an indicator of the disruption of the cell membrane. Subsequently, the impact of PEF on color and texture attributes was studied. In the final set of experiments, PEF was applied as a pre-treatment in order to accelerate the diffusion of moisture in a convective air-drying process at 70°C. / Results regarding the electrical conductivity and the changes in color revealed the similar effect of applying pulses with 100, 200 and 300 mus of duration. Increasing the number of pulses and/or the electric field strength resulted in increased electrical conductivity and discoloration rates of samples. PEF reduced the compressive strength of apple tissues between 21 to 47%. However, the compressive strength of potato tissues did not seem to be affected by the application of PEF. When PEF was applied as a pre-treatment, it caused an increase of up to 30% in the moisture diffusion coefficients of potatoes. In the case of apples, PEF pre-treated samples did not show any increase in drying rates.